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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Infrastructure for profiling code inserted by 'gcc -pg'.
  *
  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
  *
  * Originally ported from the -rt patch by:
  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
  *
  * Based on code in the latency_tracer, that is:
  *
  *  Copyright (C) 2004-2006 Ingo Molnar
  *  Copyright (C) 2004 Nadia Yvette Chambers
  */
 
 #include <linux/stop_machine.h>
 #include <linux/clocksource.h>
 #include <linux/sched/task.h>
 #include <linux/kallsyms.h>
 #include <linux/security.h>
 #include <linux/seq_file.h>
 #include <linux/tracefs.h>
 #include <linux/hardirq.h>
 #include <linux/kthread.h>
 #include <linux/uaccess.h>
 #include <linux/bsearch.h>
 #include <linux/module.h>
 #include <linux/ftrace.h>
 #include <linux/sysctl.h>
 #include <linux/slab.h>
 #include <linux/ctype.h>
 #include <linux/sort.h>
 #include <linux/list.h>
 #include <linux/hash.h>
 #include <linux/rcupdate.h>
 #include <linux/kprobes.h>
 
 #include <trace/events/sched.h>
 
 #include <asm/sections.h>
 #include <asm/setup.h>
 
 #include "ftrace_internal.h"
 #include "trace_output.h"
 #include "trace_stat.h"
 
 #define FTRACE_INVALID_FUNCTION     "__ftrace_invalid_address__"
 
 #define FTRACE_WARN_ON(cond)            \
     ({                  \
         int ___r = cond;        \
         if (WARN_ON(___r))      \
             ftrace_kill();      \
         ___r;               \
     })
 
 #define FTRACE_WARN_ON_ONCE(cond)       \
     ({                  \
         int ___r = cond;        \
         if (WARN_ON_ONCE(___r))     \
             ftrace_kill();      \
         ___r;               \
     })
 
 /* hash bits for specific function selection */
 #define FTRACE_HASH_DEFAULT_BITS 10
 #define FTRACE_HASH_MAX_BITS 12
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 #define INIT_OPS_HASH(opsname)  \
     .func_hash      = &opsname.local_hash,          \
     .local_hash.regex_lock  = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
 #else
 #define INIT_OPS_HASH(opsname)
 #endif
 
 enum {
     FTRACE_MODIFY_ENABLE_FL     = (1 << 0),
     FTRACE_MODIFY_MAY_SLEEP_FL  = (1 << 1),
 };
 
 struct ftrace_ops ftrace_list_end __read_mostly = {
     .func       = ftrace_stub,
     .flags      = FTRACE_OPS_FL_STUB,
     INIT_OPS_HASH(ftrace_list_end)
 };
 
 /* ftrace_enabled is a method to turn ftrace on or off */
 int ftrace_enabled __read_mostly;
 static int __maybe_unused last_ftrace_enabled;
 
 /* Current function tracing op */
 struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
 /* What to set function_trace_op to */
 static struct ftrace_ops *set_function_trace_op;
 
 static bool ftrace_pids_enabled(struct ftrace_ops *ops)
 {
     struct trace_array *tr;
 
     if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
         return false;
 
     tr = ops->private;
 
     return tr->function_pids != NULL || tr->function_no_pids != NULL;
 }
 
 static void ftrace_update_trampoline(struct ftrace_ops *ops);
 
 /*
  * ftrace_disabled is set when an anomaly is discovered.
  * ftrace_disabled is much stronger than ftrace_enabled.
  */
 static int ftrace_disabled __read_mostly;
 
 DEFINE_MUTEX(ftrace_lock);
 
 struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 struct ftrace_ops global_ops;
 
 /* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
 void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
               struct ftrace_ops *op, struct ftrace_regs *fregs);
 
 static inline void ftrace_ops_init(struct ftrace_ops *ops)
 {
 #ifdef CONFIG_DYNAMIC_FTRACE
     if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
         mutex_init(&ops->local_hash.regex_lock);
         ops->func_hash = &ops->local_hash;
         ops->flags |= FTRACE_OPS_FL_INITIALIZED;
     }
 #endif
 }
 
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
                 struct ftrace_ops *op, struct ftrace_regs *fregs)
 {
     struct trace_array *tr = op->private;
     int pid;
 
     if (tr) {
         pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
         if (pid == FTRACE_PID_IGNORE)
             return;
         if (pid != FTRACE_PID_TRACE &&
             pid != current->pid)
             return;
     }
 
     op->saved_func(ip, parent_ip, op, fregs);
 }
 
 static void ftrace_sync_ipi(void *data)
 {
     /* Probably not needed, but do it anyway */
     smp_rmb();
 }
 
 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 {
     /*
      * If this is a dynamic, RCU, or per CPU ops, or we force list func,
      * then it needs to call the list anyway.
      */
     if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
         FTRACE_FORCE_LIST_FUNC)
         return ftrace_ops_list_func;
 
     return ftrace_ops_get_func(ops);
 }
 
 static void update_ftrace_function(void)
 {
     ftrace_func_t func;
 
     /*
      * Prepare the ftrace_ops that the arch callback will use.
      * If there's only one ftrace_ops registered, the ftrace_ops_list
      * will point to the ops we want.
      */
     set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
                         lockdep_is_held(&ftrace_lock));
 
     /* If there's no ftrace_ops registered, just call the stub function */
     if (set_function_trace_op == &ftrace_list_end) {
         func = ftrace_stub;
 
     /*
      * If we are at the end of the list and this ops is
      * recursion safe and not dynamic and the arch supports passing ops,
      * then have the mcount trampoline call the function directly.
      */
     } else if (rcu_dereference_protected(ftrace_ops_list->next,
             lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
         func = ftrace_ops_get_list_func(ftrace_ops_list);
 
     } else {
         /* Just use the default ftrace_ops */
         set_function_trace_op = &ftrace_list_end;
         func = ftrace_ops_list_func;
     }
 
     update_function_graph_func();
 
     /* If there's no change, then do nothing more here */
     if (ftrace_trace_function == func)
         return;
 
     /*
      * If we are using the list function, it doesn't care
      * about the function_trace_ops.
      */
     if (func == ftrace_ops_list_func) {
         ftrace_trace_function = func;
         /*
          * Don't even bother setting function_trace_ops,
          * it would be racy to do so anyway.
          */
         return;
     }
 
 #ifndef CONFIG_DYNAMIC_FTRACE
     /*
      * For static tracing, we need to be a bit more careful.
      * The function change takes affect immediately. Thus,
      * we need to coordinate the setting of the function_trace_ops
      * with the setting of the ftrace_trace_function.
      *
      * Set the function to the list ops, which will call the
      * function we want, albeit indirectly, but it handles the
      * ftrace_ops and doesn't depend on function_trace_op.
      */
     ftrace_trace_function = ftrace_ops_list_func;
     /*
      * Make sure all CPUs see this. Yes this is slow, but static
      * tracing is slow and nasty to have enabled.
      */
     synchronize_rcu_tasks_rude();
     /* Now all cpus are using the list ops. */
     function_trace_op = set_function_trace_op;
     /* Make sure the function_trace_op is visible on all CPUs */
     smp_wmb();
     /* Nasty way to force a rmb on all cpus */
     smp_call_function(ftrace_sync_ipi, NULL, 1);
     /* OK, we are all set to update the ftrace_trace_function now! */
 #endif /* !CONFIG_DYNAMIC_FTRACE */
 
     ftrace_trace_function = func;
 }
 
 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
                struct ftrace_ops *ops)
 {
     rcu_assign_pointer(ops->next, *list);
 
     /*
      * We are entering ops into the list but another
      * CPU might be walking that list. We need to make sure
      * the ops->next pointer is valid before another CPU sees
      * the ops pointer included into the list.
      */
     rcu_assign_pointer(*list, ops);
 }
 
 static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
                  struct ftrace_ops *ops)
 {
     struct ftrace_ops **p;
 
     /*
      * If we are removing the last function, then simply point
      * to the ftrace_stub.
      */
     if (rcu_dereference_protected(*list,
             lockdep_is_held(&ftrace_lock)) == ops &&
         rcu_dereference_protected(ops->next,
             lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
         *list = &ftrace_list_end;
         return 0;
     }
 
     for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
         if (*p == ops)
             break;
 
     if (*p != ops)
         return -1;
 
     *p = (*p)->next;
     return 0;
 }
 
 static void ftrace_update_trampoline(struct ftrace_ops *ops);
 
 int __register_ftrace_function(struct ftrace_ops *ops)
 {
     if (ops->flags & FTRACE_OPS_FL_DELETED)
         return -EINVAL;
 
     if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
         return -EBUSY;
 
 #ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
     /*
      * If the ftrace_ops specifies SAVE_REGS, then it only can be used
      * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
      * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
      */
     if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
         !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
         return -EINVAL;
 
     if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
         ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
 #endif
     if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
         return -EBUSY;
 
     if (!is_kernel_core_data((unsigned long)ops))
         ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 
     add_ftrace_ops(&ftrace_ops_list, ops);
 
     /* Always save the function, and reset at unregistering */
     ops->saved_func = ops->func;
 
     if (ftrace_pids_enabled(ops))
         ops->func = ftrace_pid_func;
 
     ftrace_update_trampoline(ops);
 
     if (ftrace_enabled)
         update_ftrace_function();
 
     return 0;
 }
 
 int __unregister_ftrace_function(struct ftrace_ops *ops)
 {
     int ret;
 
     if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
         return -EBUSY;
 
     ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 
     if (ret < 0)
         return ret;
 
     if (ftrace_enabled)
         update_ftrace_function();
 
     ops->func = ops->saved_func;
 
     return 0;
 }
 
 static void ftrace_update_pid_func(void)
 {
     struct ftrace_ops *op;
 
     /* Only do something if we are tracing something */
     if (ftrace_trace_function == ftrace_stub)
         return;
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
         if (op->flags & FTRACE_OPS_FL_PID) {
             op->func = ftrace_pids_enabled(op) ?
                 ftrace_pid_func : op->saved_func;
             ftrace_update_trampoline(op);
         }
     } while_for_each_ftrace_op(op);
 
     update_ftrace_function();
 }
 
 #ifdef CONFIG_FUNCTION_PROFILER
 struct ftrace_profile {
     struct hlist_node       node;
     unsigned long           ip;
     unsigned long           counter;
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
     unsigned long long      time;
     unsigned long long      time_squared;
 #endif
 };
 
 struct ftrace_profile_page {
     struct ftrace_profile_page  *next;
     unsigned long           index;
     struct ftrace_profile       records[];
 };
 
 struct ftrace_profile_stat {
     atomic_t            disabled;
     struct hlist_head       *hash;
     struct ftrace_profile_page  *pages;
     struct ftrace_profile_page  *start;
     struct tracer_stat      stat;
 };
 
 #define PROFILE_RECORDS_SIZE                        \
     (PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 
 #define PROFILES_PER_PAGE                   \
     (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 
 static int ftrace_profile_enabled __read_mostly;
 
 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 static DEFINE_MUTEX(ftrace_profile_lock);
 
 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 
 #define FTRACE_PROFILE_HASH_BITS 10
 #define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
 
 static void *
 function_stat_next(void *v, int idx)
 {
     struct ftrace_profile *rec = v;
     struct ftrace_profile_page *pg;
 
     pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 
  again:
     if (idx != 0)
         rec++;
 
     if ((void *)rec >= (void *)&pg->records[pg->index]) {
         pg = pg->next;
         if (!pg)
             return NULL;
         rec = &pg->records[0];
         if (!rec->counter)
             goto again;
     }
 
     return rec;
 }
 
 static void *function_stat_start(struct tracer_stat *trace)
 {
     struct ftrace_profile_stat *stat =
         container_of(trace, struct ftrace_profile_stat, stat);
 
     if (!stat || !stat->start)
         return NULL;
 
     return function_stat_next(&stat->start->records[0], 0);
 }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 /* function graph compares on total time */
 static int function_stat_cmp(const void *p1, const void *p2)
 {
     const struct ftrace_profile *a = p1;
     const struct ftrace_profile *b = p2;
 
     if (a->time < b->time)
         return -1;
     if (a->time > b->time)
         return 1;
     else
         return 0;
 }
 #else
 /* not function graph compares against hits */
 static int function_stat_cmp(const void *p1, const void *p2)
 {
     const struct ftrace_profile *a = p1;
     const struct ftrace_profile *b = p2;
 
     if (a->counter < b->counter)
         return -1;
     if (a->counter > b->counter)
         return 1;
     else
         return 0;
 }
 #endif
 
 static int function_stat_headers(struct seq_file *m)
 {
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
     seq_puts(m, "  Function                               "
          "Hit    Time            Avg             s^2\n"
             "  --------                               "
          "---    ----            ---             ---\n");
 #else
     seq_puts(m, "  Function                               Hit\n"
             "  --------                               ---\n");
 #endif
     return 0;
 }
 
 static int function_stat_show(struct seq_file *m, void *v)
 {
     struct ftrace_profile *rec = v;
     char str[KSYM_SYMBOL_LEN];
     int ret = 0;
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
     static struct trace_seq s;
     unsigned long long avg;
     unsigned long long stddev;
 #endif
     mutex_lock(&ftrace_profile_lock);
 
     /* we raced with function_profile_reset() */
     if (unlikely(rec->counter == 0)) {
         ret = -EBUSY;
         goto out;
     }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
     avg = div64_ul(rec->time, rec->counter);
     if (tracing_thresh && (avg < tracing_thresh))
         goto out;
 #endif
 
     kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
     seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
     seq_puts(m, "    ");
 
     /* Sample standard deviation (s^2) */
     if (rec->counter <= 1)
         stddev = 0;
     else {
         /*
          * Apply Welford's method:
          * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
          */
         stddev = rec->counter * rec->time_squared -
              rec->time * rec->time;
 
         /*
          * Divide only 1000 for ns^2 -> us^2 conversion.
          * trace_print_graph_duration will divide 1000 again.
          */
         stddev = div64_ul(stddev,
                   rec->counter * (rec->counter - 1) * 1000);
     }
 
     trace_seq_init(&s);
     trace_print_graph_duration(rec->time, &s);
     trace_seq_puts(&s, "    ");
     trace_print_graph_duration(avg, &s);
     trace_seq_puts(&s, "    ");
     trace_print_graph_duration(stddev, &s);
     trace_print_seq(m, &s);
 #endif
     seq_putc(m, '\n');
 out:
     mutex_unlock(&ftrace_profile_lock);
 
     return ret;
 }
 
 static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 {
     struct ftrace_profile_page *pg;
 
     pg = stat->pages = stat->start;
 
     while (pg) {
         memset(pg->records, 0, PROFILE_RECORDS_SIZE);
         pg->index = 0;
         pg = pg->next;
     }
 
     memset(stat->hash, 0,
            FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 }
 
 static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 {
     struct ftrace_profile_page *pg;
     int functions;
     int pages;
     int i;
 
     /* If we already allocated, do nothing */
     if (stat->pages)
         return 0;
 
     stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
     if (!stat->pages)
         return -ENOMEM;
 
 #ifdef CONFIG_DYNAMIC_FTRACE
     functions = ftrace_update_tot_cnt;
 #else
     /*
      * We do not know the number of functions that exist because
      * dynamic tracing is what counts them. With past experience
      * we have around 20K functions. That should be more than enough.
      * It is highly unlikely we will execute every function in
      * the kernel.
      */
     functions = 20000;
 #endif
 
     pg = stat->start = stat->pages;
 
     pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 
     for (i = 1; i < pages; i++) {
         pg->next = (void *)get_zeroed_page(GFP_KERNEL);
         if (!pg->next)
             goto out_free;
         pg = pg->next;
     }
 
     return 0;
 
  out_free:
     pg = stat->start;
     while (pg) {
         unsigned long tmp = (unsigned long)pg;
 
         pg = pg->next;
         free_page(tmp);
     }
 
     stat->pages = NULL;
     stat->start = NULL;
 
     return -ENOMEM;
 }
 
 static int ftrace_profile_init_cpu(int cpu)
 {
     struct ftrace_profile_stat *stat;
     int size;
 
     stat = &per_cpu(ftrace_profile_stats, cpu);
 
     if (stat->hash) {
         /* If the profile is already created, simply reset it */
         ftrace_profile_reset(stat);
         return 0;
     }
 
     /*
      * We are profiling all functions, but usually only a few thousand
      * functions are hit. We'll make a hash of 1024 items.
      */
     size = FTRACE_PROFILE_HASH_SIZE;
 
     stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
 
     if (!stat->hash)
         return -ENOMEM;
 
     /* Preallocate the function profiling pages */
     if (ftrace_profile_pages_init(stat) < 0) {
         kfree(stat->hash);
         stat->hash = NULL;
         return -ENOMEM;
     }
 
     return 0;
 }
 
 static int ftrace_profile_init(void)
 {
     int cpu;
     int ret = 0;
 
     for_each_possible_cpu(cpu) {
         ret = ftrace_profile_init_cpu(cpu);
         if (ret)
             break;
     }
 
     return ret;
 }
 
 /* interrupts must be disabled */
 static struct ftrace_profile *
 ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 {
     struct ftrace_profile *rec;
     struct hlist_head *hhd;
     unsigned long key;
 
     key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
     hhd = &stat->hash[key];
 
     if (hlist_empty(hhd))
         return NULL;
 
     hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
         if (rec->ip == ip)
             return rec;
     }
 
     return NULL;
 }
 
 static void ftrace_add_profile(struct ftrace_profile_stat *stat,
                    struct ftrace_profile *rec)
 {
     unsigned long key;
 
     key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
     hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 }
 
 /*
  * The memory is already allocated, this simply finds a new record to use.
  */
 static struct ftrace_profile *
 ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 {
     struct ftrace_profile *rec = NULL;
 
     /* prevent recursion (from NMIs) */
     if (atomic_inc_return(&stat->disabled) != 1)
         goto out;
 
     /*
      * Try to find the function again since an NMI
      * could have added it
      */
     rec = ftrace_find_profiled_func(stat, ip);
     if (rec)
         goto out;
 
     if (stat->pages->index == PROFILES_PER_PAGE) {
         if (!stat->pages->next)
             goto out;
         stat->pages = stat->pages->next;
     }
 
     rec = &stat->pages->records[stat->pages->index++];
     rec->ip = ip;
     ftrace_add_profile(stat, rec);
 
  out:
     atomic_dec(&stat->disabled);
 
     return rec;
 }
 
 static void
 function_profile_call(unsigned long ip, unsigned long parent_ip,
               struct ftrace_ops *ops, struct ftrace_regs *fregs)
 {
     struct ftrace_profile_stat *stat;
     struct ftrace_profile *rec;
     unsigned long flags;
 
     if (!ftrace_profile_enabled)
         return;
 
     local_irq_save(flags);
 
     stat = this_cpu_ptr(&ftrace_profile_stats);
     if (!stat->hash || !ftrace_profile_enabled)
         goto out;
 
     rec = ftrace_find_profiled_func(stat, ip);
     if (!rec) {
         rec = ftrace_profile_alloc(stat, ip);
         if (!rec)
             goto out;
     }
 
     rec->counter++;
  out:
     local_irq_restore(flags);
 }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static bool fgraph_graph_time = true;
 
 void ftrace_graph_graph_time_control(bool enable)
 {
     fgraph_graph_time = enable;
 }
 
 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 {
     struct ftrace_ret_stack *ret_stack;
 
     function_profile_call(trace->func, 0, NULL, NULL);
 
     /* If function graph is shutting down, ret_stack can be NULL */
     if (!current->ret_stack)
         return 0;
 
     ret_stack = ftrace_graph_get_ret_stack(current, 0);
     if (ret_stack)
         ret_stack->subtime = 0;
 
     return 1;
 }
 
 static void profile_graph_return(struct ftrace_graph_ret *trace)
 {
     struct ftrace_ret_stack *ret_stack;
     struct ftrace_profile_stat *stat;
     unsigned long long calltime;
     struct ftrace_profile *rec;
     unsigned long flags;
 
     local_irq_save(flags);
     stat = this_cpu_ptr(&ftrace_profile_stats);
     if (!stat->hash || !ftrace_profile_enabled)
         goto out;
 
     /* If the calltime was zero'd ignore it */
     if (!trace->calltime)
         goto out;
 
     calltime = trace->rettime - trace->calltime;
 
     if (!fgraph_graph_time) {
 
         /* Append this call time to the parent time to subtract */
         ret_stack = ftrace_graph_get_ret_stack(current, 1);
         if (ret_stack)
             ret_stack->subtime += calltime;
 
         ret_stack = ftrace_graph_get_ret_stack(current, 0);
         if (ret_stack && ret_stack->subtime < calltime)
             calltime -= ret_stack->subtime;
         else
             calltime = 0;
     }
 
     rec = ftrace_find_profiled_func(stat, trace->func);
     if (rec) {
         rec->time += calltime;
         rec->time_squared += calltime * calltime;
     }
 
  out:
     local_irq_restore(flags);
 }
 
 static struct fgraph_ops fprofiler_ops = {
     .entryfunc = &profile_graph_entry,
     .retfunc = &profile_graph_return,
 };
 
 static int register_ftrace_profiler(void)
 {
     return register_ftrace_graph(&fprofiler_ops);
 }
 
 static void unregister_ftrace_profiler(void)
 {
     unregister_ftrace_graph(&fprofiler_ops);
 }
 #else
 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
     .func       = function_profile_call,
     .flags      = FTRACE_OPS_FL_INITIALIZED,
     INIT_OPS_HASH(ftrace_profile_ops)
 };
 
 static int register_ftrace_profiler(void)
 {
     return register_ftrace_function(&ftrace_profile_ops);
 }
 
 static void unregister_ftrace_profiler(void)
 {
     unregister_ftrace_function(&ftrace_profile_ops);
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 static ssize_t
 ftrace_profile_write(struct file *filp, const char __user *ubuf,
              size_t cnt, loff_t *ppos)
 {
     unsigned long val;
     int ret;
 
     ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
     if (ret)
         return ret;
 
     val = !!val;
 
     mutex_lock(&ftrace_profile_lock);
     if (ftrace_profile_enabled ^ val) {
         if (val) {
             ret = ftrace_profile_init();
             if (ret < 0) {
                 cnt = ret;
                 goto out;
             }
 
             ret = register_ftrace_profiler();
             if (ret < 0) {
                 cnt = ret;
                 goto out;
             }
             ftrace_profile_enabled = 1;
         } else {
             ftrace_profile_enabled = 0;
             /*
              * unregister_ftrace_profiler calls stop_machine
              * so this acts like an synchronize_rcu.
              */
             unregister_ftrace_profiler();
         }
     }
  out:
     mutex_unlock(&ftrace_profile_lock);
 
     *ppos += cnt;
 
     return cnt;
 }
 
 static ssize_t
 ftrace_profile_read(struct file *filp, char __user *ubuf,
              size_t cnt, loff_t *ppos)
 {
     char buf[64];       /* big enough to hold a number */
     int r;
 
     r = sprintf(buf, "%u\n", ftrace_profile_enabled);
     return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
 static const struct file_operations ftrace_profile_fops = {
     .open       = tracing_open_generic,
     .read       = ftrace_profile_read,
     .write      = ftrace_profile_write,
     .llseek     = default_llseek,
 };
 
 /* used to initialize the real stat files */
 static struct tracer_stat function_stats __initdata = {
     .name       = "functions",
     .stat_start = function_stat_start,
     .stat_next  = function_stat_next,
     .stat_cmp   = function_stat_cmp,
     .stat_headers   = function_stat_headers,
     .stat_show  = function_stat_show
 };
 
 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 {
     struct ftrace_profile_stat *stat;
     char *name;
     int ret;
     int cpu;
 
     for_each_possible_cpu(cpu) {
         stat = &per_cpu(ftrace_profile_stats, cpu);
 
         name = kasprintf(GFP_KERNEL, "function%d", cpu);
         if (!name) {
             /*
              * The files created are permanent, if something happens
              * we still do not free memory.
              */
             WARN(1,
                  "Could not allocate stat file for cpu %d\n",
                  cpu);
             return;
         }
         stat->stat = function_stats;
         stat->stat.name = name;
         ret = register_stat_tracer(&stat->stat);
         if (ret) {
             WARN(1,
                  "Could not register function stat for cpu %d\n",
                  cpu);
             kfree(name);
             return;
         }
     }
 
     trace_create_file("function_profile_enabled",
               TRACE_MODE_WRITE, d_tracer, NULL,
               &ftrace_profile_fops);
 }
 
 #else /* CONFIG_FUNCTION_PROFILER */
 static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 {
 }
 #endif /* CONFIG_FUNCTION_PROFILER */
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 static struct ftrace_ops *removed_ops;
 
 /*
  * Set when doing a global update, like enabling all recs or disabling them.
  * It is not set when just updating a single ftrace_ops.
  */
 static bool update_all_ops;
 
 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 # error Dynamic ftrace depends on MCOUNT_RECORD
 #endif
 
 struct ftrace_func_probe {
     struct ftrace_probe_ops *probe_ops;
     struct ftrace_ops   ops;
     struct trace_array  *tr;
     struct list_head    list;
     void            *data;
     int         ref;
 };
 
 /*
  * We make these constant because no one should touch them,
  * but they are used as the default "empty hash", to avoid allocating
  * it all the time. These are in a read only section such that if
  * anyone does try to modify it, it will cause an exception.
  */
 static const struct hlist_head empty_buckets[1];
 static const struct ftrace_hash empty_hash = {
     .buckets = (struct hlist_head *)empty_buckets,
 };
 #define EMPTY_HASH  ((struct ftrace_hash *)&empty_hash)
 
 struct ftrace_ops global_ops = {
     .func               = ftrace_stub,
     .local_hash.notrace_hash    = EMPTY_HASH,
     .local_hash.filter_hash     = EMPTY_HASH,
     INIT_OPS_HASH(global_ops)
     .flags              = FTRACE_OPS_FL_INITIALIZED |
                       FTRACE_OPS_FL_PID,
 };
 
 /*
  * Used by the stack unwinder to know about dynamic ftrace trampolines.
  */
 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
 {
     struct ftrace_ops *op = NULL;
 
     /*
      * Some of the ops may be dynamically allocated,
      * they are freed after a synchronize_rcu().
      */
     preempt_disable_notrace();
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
         /*
          * This is to check for dynamically allocated trampolines.
          * Trampolines that are in kernel text will have
          * core_kernel_text() return true.
          */
         if (op->trampoline && op->trampoline_size)
             if (addr >= op->trampoline &&
                 addr < op->trampoline + op->trampoline_size) {
                 preempt_enable_notrace();
                 return op;
             }
     } while_for_each_ftrace_op(op);
     preempt_enable_notrace();
 
     return NULL;
 }
 
 /*
  * This is used by __kernel_text_address() to return true if the
  * address is on a dynamically allocated trampoline that would
  * not return true for either core_kernel_text() or
  * is_module_text_address().
  */
 bool is_ftrace_trampoline(unsigned long addr)
 {
     return ftrace_ops_trampoline(addr) != NULL;
 }
 
 struct ftrace_page {
     struct ftrace_page  *next;
     struct dyn_ftrace   *records;
     int         index;
     int         order;
 };
 
 #define ENTRY_SIZE sizeof(struct dyn_ftrace)
 #define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
 
 static struct ftrace_page   *ftrace_pages_start;
 static struct ftrace_page   *ftrace_pages;
 
 static __always_inline unsigned long
 ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
 {
     if (hash->size_bits > 0)
         return hash_long(ip, hash->size_bits);
 
     return 0;
 }
 
 /* Only use this function if ftrace_hash_empty() has already been tested */
 static __always_inline struct ftrace_func_entry *
 __ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
 {
     unsigned long key;
     struct ftrace_func_entry *entry;
     struct hlist_head *hhd;
 
     key = ftrace_hash_key(hash, ip);
     hhd = &hash->buckets[key];
 
     hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
         if (entry->ip == ip)
             return entry;
     }
     return NULL;
 }
 
 /**
  * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
  * @hash: The hash to look at
  * @ip: The instruction pointer to test
  *
  * Search a given @hash to see if a given instruction pointer (@ip)
  * exists in it.
  *
  * Returns the entry that holds the @ip if found. NULL otherwise.
  */
 struct ftrace_func_entry *
 ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
 {
     if (ftrace_hash_empty(hash))
         return NULL;
 
     return __ftrace_lookup_ip(hash, ip);
 }
 
 static void __add_hash_entry(struct ftrace_hash *hash,
                  struct ftrace_func_entry *entry)
 {
     struct hlist_head *hhd;
     unsigned long key;
 
     key = ftrace_hash_key(hash, entry->ip);
     hhd = &hash->buckets[key];
     hlist_add_head(&entry->hlist, hhd);
     hash->count++;
 }
 
 static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
 {
     struct ftrace_func_entry *entry;
 
     entry = kmalloc(sizeof(*entry), GFP_KERNEL);
     if (!entry)
         return -ENOMEM;
 
     entry->ip = ip;
     __add_hash_entry(hash, entry);
 
     return 0;
 }
 
 static void
 free_hash_entry(struct ftrace_hash *hash,
           struct ftrace_func_entry *entry)
 {
     hlist_del(&entry->hlist);
     kfree(entry);
     hash->count--;
 }
 
 static void
 remove_hash_entry(struct ftrace_hash *hash,
           struct ftrace_func_entry *entry)
 {
     hlist_del_rcu(&entry->hlist);
     hash->count--;
 }
 
 static void ftrace_hash_clear(struct ftrace_hash *hash)
 {
     struct hlist_head *hhd;
     struct hlist_node *tn;
     struct ftrace_func_entry *entry;
     int size = 1 << hash->size_bits;
     int i;
 
     if (!hash->count)
         return;
 
     for (i = 0; i < size; i++) {
         hhd = &hash->buckets[i];
         hlist_for_each_entry_safe(entry, tn, hhd, hlist)
             free_hash_entry(hash, entry);
     }
     FTRACE_WARN_ON(hash->count);
 }
 
 static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
 {
     list_del(&ftrace_mod->list);
     kfree(ftrace_mod->module);
     kfree(ftrace_mod->func);
     kfree(ftrace_mod);
 }
 
 static void clear_ftrace_mod_list(struct list_head *head)
 {
     struct ftrace_mod_load *p, *n;
 
     /* stack tracer isn't supported yet */
     if (!head)
         return;
 
     mutex_lock(&ftrace_lock);
     list_for_each_entry_safe(p, n, head, list)
         free_ftrace_mod(p);
     mutex_unlock(&ftrace_lock);
 }
 
 static void free_ftrace_hash(struct ftrace_hash *hash)
 {
     if (!hash || hash == EMPTY_HASH)
         return;
     ftrace_hash_clear(hash);
     kfree(hash->buckets);
     kfree(hash);
 }
 
 static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
 {
     struct ftrace_hash *hash;
 
     hash = container_of(rcu, struct ftrace_hash, rcu);
     free_ftrace_hash(hash);
 }
 
 static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
 {
     if (!hash || hash == EMPTY_HASH)
         return;
     call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
 }
 
 void ftrace_free_filter(struct ftrace_ops *ops)
 {
     ftrace_ops_init(ops);
     free_ftrace_hash(ops->func_hash->filter_hash);
     free_ftrace_hash(ops->func_hash->notrace_hash);
 }
 
 static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
 {
     struct ftrace_hash *hash;
     int size;
 
     hash = kzalloc(sizeof(*hash), GFP_KERNEL);
     if (!hash)
         return NULL;
 
     size = 1 << size_bits;
     hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
 
     if (!hash->buckets) {
         kfree(hash);
         return NULL;
     }
 
     hash->size_bits = size_bits;
 
     return hash;
 }
 
 
 static int ftrace_add_mod(struct trace_array *tr,
               const char *func, const char *module,
               int enable)
 {
     struct ftrace_mod_load *ftrace_mod;
     struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
 
     ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
     if (!ftrace_mod)
         return -ENOMEM;
 
     ftrace_mod->func = kstrdup(func, GFP_KERNEL);
     ftrace_mod->module = kstrdup(module, GFP_KERNEL);
     ftrace_mod->enable = enable;
 
     if (!ftrace_mod->func || !ftrace_mod->module)
         goto out_free;
 
     list_add(&ftrace_mod->list, mod_head);
 
     return 0;
 
  out_free:
     free_ftrace_mod(ftrace_mod);
 
     return -ENOMEM;
 }
 
 static struct ftrace_hash *
 alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_hash *new_hash;
     int size;
     int ret;
     int i;
 
     new_hash = alloc_ftrace_hash(size_bits);
     if (!new_hash)
         return NULL;
 
     if (hash)
         new_hash->flags = hash->flags;
 
     /* Empty hash? */
     if (ftrace_hash_empty(hash))
         return new_hash;
 
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             ret = add_hash_entry(new_hash, entry->ip);
             if (ret < 0)
                 goto free_hash;
         }
     }
 
     FTRACE_WARN_ON(new_hash->count != hash->count);
 
     return new_hash;
 
  free_hash:
     free_ftrace_hash(new_hash);
     return NULL;
 }
 
 static void
 ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
 static void
 ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
 
 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
                        struct ftrace_hash *new_hash);
 
 static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_hash *new_hash;
     struct hlist_head *hhd;
     struct hlist_node *tn;
     int bits = 0;
     int i;
 
     /*
      * Use around half the size (max bit of it), but
      * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
      */
     bits = fls(size / 2);
 
     /* Don't allocate too much */
     if (bits > FTRACE_HASH_MAX_BITS)
         bits = FTRACE_HASH_MAX_BITS;
 
     new_hash = alloc_ftrace_hash(bits);
     if (!new_hash)
         return NULL;
 
     new_hash->flags = src->flags;
 
     size = 1 << src->size_bits;
     for (i = 0; i < size; i++) {
         hhd = &src->buckets[i];
         hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
             remove_hash_entry(src, entry);
             __add_hash_entry(new_hash, entry);
         }
     }
     return new_hash;
 }
 
 static struct ftrace_hash *
 __ftrace_hash_move(struct ftrace_hash *src)
 {
     int size = src->count;
 
     /*
      * If the new source is empty, just return the empty_hash.
      */
     if (ftrace_hash_empty(src))
         return EMPTY_HASH;
 
     return dup_hash(src, size);
 }
 
 static int
 ftrace_hash_move(struct ftrace_ops *ops, int enable,
          struct ftrace_hash **dst, struct ftrace_hash *src)
 {
     struct ftrace_hash *new_hash;
     int ret;
 
     /* Reject setting notrace hash on IPMODIFY ftrace_ops */
     if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
         return -EINVAL;
 
     new_hash = __ftrace_hash_move(src);
     if (!new_hash)
         return -ENOMEM;
 
     /* Make sure this can be applied if it is IPMODIFY ftrace_ops */
     if (enable) {
         /* IPMODIFY should be updated only when filter_hash updating */
         ret = ftrace_hash_ipmodify_update(ops, new_hash);
         if (ret < 0) {
             free_ftrace_hash(new_hash);
             return ret;
         }
     }
 
     /*
      * Remove the current set, update the hash and add
      * them back.
      */
     ftrace_hash_rec_disable_modify(ops, enable);
 
     rcu_assign_pointer(*dst, new_hash);
 
     ftrace_hash_rec_enable_modify(ops, enable);
 
     return 0;
 }
 
 static bool hash_contains_ip(unsigned long ip,
                  struct ftrace_ops_hash *hash)
 {
     /*
      * The function record is a match if it exists in the filter
      * hash and not in the notrace hash. Note, an empty hash is
      * considered a match for the filter hash, but an empty
      * notrace hash is considered not in the notrace hash.
      */
     return (ftrace_hash_empty(hash->filter_hash) ||
         __ftrace_lookup_ip(hash->filter_hash, ip)) &&
         (ftrace_hash_empty(hash->notrace_hash) ||
          !__ftrace_lookup_ip(hash->notrace_hash, ip));
 }
 
 /*
  * Test the hashes for this ops to see if we want to call
  * the ops->func or not.
  *
  * It's a match if the ip is in the ops->filter_hash or
  * the filter_hash does not exist or is empty,
  *  AND
  * the ip is not in the ops->notrace_hash.
  *
  * This needs to be called with preemption disabled as
  * the hashes are freed with call_rcu().
  */
 int
 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
     struct ftrace_ops_hash hash;
     int ret;
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
     /*
      * There's a small race when adding ops that the ftrace handler
      * that wants regs, may be called without them. We can not
      * allow that handler to be called if regs is NULL.
      */
     if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
         return 0;
 #endif
 
     rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
     rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
 
     if (hash_contains_ip(ip, &hash))
         ret = 1;
     else
         ret = 0;
 
     return ret;
 }
 
 /*
  * This is a double for. Do not use 'break' to break out of the loop,
  * you must use a goto.
  */
 #define do_for_each_ftrace_rec(pg, rec)                 \
     for (pg = ftrace_pages_start; pg; pg = pg->next) {      \
         int _____i;                     \
         for (_____i = 0; _____i < pg->index; _____i++) {    \
             rec = &pg->records[_____i];
 
 #define while_for_each_ftrace_rec()     \
         }               \
     }
 
 
 static int ftrace_cmp_recs(const void *a, const void *b)
 {
     const struct dyn_ftrace *key = a;
     const struct dyn_ftrace *rec = b;
 
     if (key->flags < rec->ip)
         return -1;
     if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
         return 1;
     return 0;
 }
 
 static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
 {
     struct ftrace_page *pg;
     struct dyn_ftrace *rec = NULL;
     struct dyn_ftrace key;
 
     key.ip = start;
     key.flags = end;    /* overload flags, as it is unsigned long */
 
     for (pg = ftrace_pages_start; pg; pg = pg->next) {
         if (end < pg->records[0].ip ||
             start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
             continue;
         rec = bsearch(&key, pg->records, pg->index,
                   sizeof(struct dyn_ftrace),
                   ftrace_cmp_recs);
         if (rec)
             break;
     }
     return rec;
 }
 
 /**
  * ftrace_location_range - return the first address of a traced location
  *  if it touches the given ip range
  * @start: start of range to search.
  * @end: end of range to search (inclusive). @end points to the last byte
  *  to check.
  *
  * Returns rec->ip if the related ftrace location is a least partly within
  * the given address range. That is, the first address of the instruction
  * that is either a NOP or call to the function tracer. It checks the ftrace
  * internal tables to determine if the address belongs or not.
  */
 unsigned long ftrace_location_range(unsigned long start, unsigned long end)
 {
     struct dyn_ftrace *rec;
 
     rec = lookup_rec(start, end);
     if (rec)
         return rec->ip;
 
     return 0;
 }
 
 /**
  * ftrace_location - return the ftrace location
  * @ip: the instruction pointer to check
  *
  * If @ip matches the ftrace location, return @ip.
  * If @ip matches sym+0, return sym's ftrace location.
  * Otherwise, return 0.
  */
 unsigned long ftrace_location(unsigned long ip)
 {
     struct dyn_ftrace *rec;
     unsigned long offset;
     unsigned long size;
 
     rec = lookup_rec(ip, ip);
     if (!rec) {
         if (!kallsyms_lookup_size_offset(ip, &size, &offset))
             goto out;
 
         /* map sym+0 to __fentry__ */
         if (!offset)
             rec = lookup_rec(ip, ip + size - 1);
     }
 
     if (rec)
         return rec->ip;
 
 out:
     return 0;
 }
 
 /**
  * ftrace_text_reserved - return true if range contains an ftrace location
  * @start: start of range to search
  * @end: end of range to search (inclusive). @end points to the last byte to check.
  *
  * Returns 1 if @start and @end contains a ftrace location.
  * That is, the instruction that is either a NOP or call to
  * the function tracer. It checks the ftrace internal tables to
  * determine if the address belongs or not.
  */
 int ftrace_text_reserved(const void *start, const void *end)
 {
     unsigned long ret;
 
     ret = ftrace_location_range((unsigned long)start,
                     (unsigned long)end);
 
     return (int)!!ret;
 }
 
 /* Test if ops registered to this rec needs regs */
 static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
 {
     struct ftrace_ops *ops;
     bool keep_regs = false;
 
     for (ops = ftrace_ops_list;
          ops != &ftrace_list_end; ops = ops->next) {
         /* pass rec in as regs to have non-NULL val */
         if (ftrace_ops_test(ops, rec->ip, rec)) {
             if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
                 keep_regs = true;
                 break;
             }
         }
     }
 
     return  keep_regs;
 }
 
 static struct ftrace_ops *
 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
 static struct ftrace_ops *
 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
 static struct ftrace_ops *
 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
 
 static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
                      int filter_hash,
                      bool inc)
 {
     struct ftrace_hash *hash;
     struct ftrace_hash *other_hash;
     struct ftrace_page *pg;
     struct dyn_ftrace *rec;
     bool update = false;
     int count = 0;
     int all = false;
 
     /* Only update if the ops has been registered */
     if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
         return false;
 
     /*
      * In the filter_hash case:
      *   If the count is zero, we update all records.
      *   Otherwise we just update the items in the hash.
      *
      * In the notrace_hash case:
      *   We enable the update in the hash.
      *   As disabling notrace means enabling the tracing,
      *   and enabling notrace means disabling, the inc variable
      *   gets inversed.
      */
     if (filter_hash) {
         hash = ops->func_hash->filter_hash;
         other_hash = ops->func_hash->notrace_hash;
         if (ftrace_hash_empty(hash))
             all = true;
     } else {
         inc = !inc;
         hash = ops->func_hash->notrace_hash;
         other_hash = ops->func_hash->filter_hash;
         /*
          * If the notrace hash has no items,
          * then there's nothing to do.
          */
         if (ftrace_hash_empty(hash))
             return false;
     }
 
     do_for_each_ftrace_rec(pg, rec) {
         int in_other_hash = 0;
         int in_hash = 0;
         int match = 0;
 
         if (rec->flags & FTRACE_FL_DISABLED)
             continue;
 
         if (all) {
             /*
              * Only the filter_hash affects all records.
              * Update if the record is not in the notrace hash.
              */
             if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
                 match = 1;
         } else {
             in_hash = !!ftrace_lookup_ip(hash, rec->ip);
             in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
 
             /*
              * If filter_hash is set, we want to match all functions
              * that are in the hash but not in the other hash.
              *
              * If filter_hash is not set, then we are decrementing.
              * That means we match anything that is in the hash
              * and also in the other_hash. That is, we need to turn
              * off functions in the other hash because they are disabled
              * by this hash.
              */
             if (filter_hash && in_hash && !in_other_hash)
                 match = 1;
             else if (!filter_hash && in_hash &&
                  (in_other_hash || ftrace_hash_empty(other_hash)))
                 match = 1;
         }
         if (!match)
             continue;
 
         if (inc) {
             rec->flags++;
             if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
                 return false;
 
             if (ops->flags & FTRACE_OPS_FL_DIRECT)
                 rec->flags |= FTRACE_FL_DIRECT;
 
             /*
              * If there's only a single callback registered to a
              * function, and the ops has a trampoline registered
              * for it, then we can call it directly.
              */
             if (ftrace_rec_count(rec) == 1 && ops->trampoline)
                 rec->flags |= FTRACE_FL_TRAMP;
             else
                 /*
                  * If we are adding another function callback
                  * to this function, and the previous had a
                  * custom trampoline in use, then we need to go
                  * back to the default trampoline.
                  */
                 rec->flags &= ~FTRACE_FL_TRAMP;
 
             /*
              * If any ops wants regs saved for this function
              * then all ops will get saved regs.
              */
             if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
                 rec->flags |= FTRACE_FL_REGS;
         } else {
             if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
                 return false;
             rec->flags--;
 
             /*
              * Only the internal direct_ops should have the
              * DIRECT flag set. Thus, if it is removing a
              * function, then that function should no longer
              * be direct.
              */
             if (ops->flags & FTRACE_OPS_FL_DIRECT)
                 rec->flags &= ~FTRACE_FL_DIRECT;
 
             /*
              * If the rec had REGS enabled and the ops that is
              * being removed had REGS set, then see if there is
              * still any ops for this record that wants regs.
              * If not, we can stop recording them.
              */
             if (ftrace_rec_count(rec) > 0 &&
                 rec->flags & FTRACE_FL_REGS &&
                 ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
                 if (!test_rec_ops_needs_regs(rec))
                     rec->flags &= ~FTRACE_FL_REGS;
             }
 
             /*
              * The TRAMP needs to be set only if rec count
              * is decremented to one, and the ops that is
              * left has a trampoline. As TRAMP can only be
              * enabled if there is only a single ops attached
              * to it.
              */
             if (ftrace_rec_count(rec) == 1 &&
                 ftrace_find_tramp_ops_any_other(rec, ops))
                 rec->flags |= FTRACE_FL_TRAMP;
             else
                 rec->flags &= ~FTRACE_FL_TRAMP;
 
             /*
              * flags will be cleared in ftrace_check_record()
              * if rec count is zero.
              */
         }
         count++;
 
         /* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
         update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
 
         /* Shortcut, if we handled all records, we are done. */
         if (!all && count == hash->count)
             return update;
     } while_for_each_ftrace_rec();
 
     return update;
 }
 
 static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
                     int filter_hash)
 {
     return __ftrace_hash_rec_update(ops, filter_hash, 0);
 }
 
 static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
                    int filter_hash)
 {
     return __ftrace_hash_rec_update(ops, filter_hash, 1);
 }
 
 static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
                       int filter_hash, int inc)
 {
     struct ftrace_ops *op;
 
     __ftrace_hash_rec_update(ops, filter_hash, inc);
 
     if (ops->func_hash != &global_ops.local_hash)
         return;
 
     /*
      * If the ops shares the global_ops hash, then we need to update
      * all ops that are enabled and use this hash.
      */
     do_for_each_ftrace_op(op, ftrace_ops_list) {
         /* Already done */
         if (op == ops)
             continue;
         if (op->func_hash == &global_ops.local_hash)
             __ftrace_hash_rec_update(op, filter_hash, inc);
     } while_for_each_ftrace_op(op);
 }
 
 static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
                        int filter_hash)
 {
     ftrace_hash_rec_update_modify(ops, filter_hash, 0);
 }
 
 static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
                       int filter_hash)
 {
     ftrace_hash_rec_update_modify(ops, filter_hash, 1);
 }
 
 /*
  * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
  * or no-needed to update, -EBUSY if it detects a conflict of the flag
  * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
  * Note that old_hash and new_hash has below meanings
  *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
  *  - If the hash is EMPTY_HASH, it hits nothing
  *  - Anything else hits the recs which match the hash entries.
  *
  * DIRECT ops does not have IPMODIFY flag, but we still need to check it
  * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
  * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
  * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
  * the return value to the caller and eventually to the owner of the DIRECT
  * ops.
  */
 static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
                      struct ftrace_hash *old_hash,
                      struct ftrace_hash *new_hash)
 {
     struct ftrace_page *pg;
     struct dyn_ftrace *rec, *end = NULL;
     int in_old, in_new;
     bool is_ipmodify, is_direct;
 
     /* Only update if the ops has been registered */
     if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
         return 0;
 
     is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
     is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
 
     /* neither IPMODIFY nor DIRECT, skip */
     if (!is_ipmodify && !is_direct)
         return 0;
 
     if (WARN_ON_ONCE(is_ipmodify && is_direct))
         return 0;
 
     /*
      * Since the IPMODIFY and DIRECT are very address sensitive
      * actions, we do not allow ftrace_ops to set all functions to new
      * hash.
      */
     if (!new_hash || !old_hash)
         return -EINVAL;
 
     /* Update rec->flags */
     do_for_each_ftrace_rec(pg, rec) {
 
         if (rec->flags & FTRACE_FL_DISABLED)
             continue;
 
         /* We need to update only differences of filter_hash */
         in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
         in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
         if (in_old == in_new)
             continue;
 
         if (in_new) {
             if (rec->flags & FTRACE_FL_IPMODIFY) {
                 int ret;
 
                 /* Cannot have two ipmodify on same rec */
                 if (is_ipmodify)
                     goto rollback;
 
                 FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
 
                 /*
                  * Another ops with IPMODIFY is already
                  * attached. We are now attaching a direct
                  * ops. Run SHARE_IPMODIFY_SELF, to check
                  * whether sharing is supported.
                  */
                 if (!ops->ops_func)
                     return -EBUSY;
                 ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
                 if (ret)
                     return ret;
             } else if (is_ipmodify) {
                 rec->flags |= FTRACE_FL_IPMODIFY;
             }
         } else if (is_ipmodify) {
             rec->flags &= ~FTRACE_FL_IPMODIFY;
         }
     } while_for_each_ftrace_rec();
 
     return 0;
 
 rollback:
     end = rec;
 
     /* Roll back what we did above */
     do_for_each_ftrace_rec(pg, rec) {
 
         if (rec->flags & FTRACE_FL_DISABLED)
             continue;
 
         if (rec == end)
             goto err_out;
 
         in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
         in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
         if (in_old == in_new)
             continue;
 
         if (in_new)
             rec->flags &= ~FTRACE_FL_IPMODIFY;
         else
             rec->flags |= FTRACE_FL_IPMODIFY;
     } while_for_each_ftrace_rec();
 
 err_out:
     return -EBUSY;
 }
 
 static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
 {
     struct ftrace_hash *hash = ops->func_hash->filter_hash;
 
     if (ftrace_hash_empty(hash))
         hash = NULL;
 
     return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
 }
 
 /* Disabling always succeeds */
 static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
 {
     struct ftrace_hash *hash = ops->func_hash->filter_hash;
 
     if (ftrace_hash_empty(hash))
         hash = NULL;
 
     __ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
 }
 
 static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
                        struct ftrace_hash *new_hash)
 {
     struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
 
     if (ftrace_hash_empty(old_hash))
         old_hash = NULL;
 
     if (ftrace_hash_empty(new_hash))
         new_hash = NULL;
 
     return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
 }
 
 static void print_ip_ins(const char *fmt, const unsigned char *p)
 {
     char ins[MCOUNT_INSN_SIZE];
     int i;
 
     if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
         printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
         return;
     }
 
     printk(KERN_CONT "%s", fmt);
 
     for (i = 0; i < MCOUNT_INSN_SIZE; i++)
         printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]);
 }
 
 enum ftrace_bug_type ftrace_bug_type;
 const void *ftrace_expected;
 
 static void print_bug_type(void)
 {
     switch (ftrace_bug_type) {
     case FTRACE_BUG_UNKNOWN:
         break;
     case FTRACE_BUG_INIT:
         pr_info("Initializing ftrace call sites\n");
         break;
     case FTRACE_BUG_NOP:
         pr_info("Setting ftrace call site to NOP\n");
         break;
     case FTRACE_BUG_CALL:
         pr_info("Setting ftrace call site to call ftrace function\n");
         break;
     case FTRACE_BUG_UPDATE:
         pr_info("Updating ftrace call site to call a different ftrace function\n");
         break;
     }
 }
 
 /**
  * ftrace_bug - report and shutdown function tracer
  * @failed: The failed type (EFAULT, EINVAL, EPERM)
  * @rec: The record that failed
  *
  * The arch code that enables or disables the function tracing
  * can call ftrace_bug() when it has detected a problem in
  * modifying the code. @failed should be one of either:
  * EFAULT - if the problem happens on reading the @ip address
  * EINVAL - if what is read at @ip is not what was expected
  * EPERM - if the problem happens on writing to the @ip address
  */
 void ftrace_bug(int failed, struct dyn_ftrace *rec)
 {
     unsigned long ip = rec ? rec->ip : 0;
 
     pr_info("------------[ ftrace bug ]------------\n");
 
     switch (failed) {
     case -EFAULT:
         pr_info("ftrace faulted on modifying ");
         print_ip_sym(KERN_INFO, ip);
         break;
     case -EINVAL:
         pr_info("ftrace failed to modify ");
         print_ip_sym(KERN_INFO, ip);
         print_ip_ins(" actual:   ", (unsigned char *)ip);
         pr_cont("\n");
         if (ftrace_expected) {
             print_ip_ins(" expected: ", ftrace_expected);
             pr_cont("\n");
         }
         break;
     case -EPERM:
         pr_info("ftrace faulted on writing ");
         print_ip_sym(KERN_INFO, ip);
         break;
     default:
         pr_info("ftrace faulted on unknown error ");
         print_ip_sym(KERN_INFO, ip);
     }
     print_bug_type();
     if (rec) {
         struct ftrace_ops *ops = NULL;
 
         pr_info("ftrace record flags: %lx\n", rec->flags);
         pr_cont(" (%ld)%s", ftrace_rec_count(rec),
             rec->flags & FTRACE_FL_REGS ? " R" : "  ");
         if (rec->flags & FTRACE_FL_TRAMP_EN) {
             ops = ftrace_find_tramp_ops_any(rec);
             if (ops) {
                 do {
                     pr_cont("\ttramp: %pS (%pS)",
                         (void *)ops->trampoline,
                         (void *)ops->func);
                     ops = ftrace_find_tramp_ops_next(rec, ops);
                 } while (ops);
             } else
                 pr_cont("\ttramp: ERROR!");
 
         }
         ip = ftrace_get_addr_curr(rec);
         pr_cont("\n expected tramp: %lx\n", ip);
     }
 
     FTRACE_WARN_ON_ONCE(1);
 }
 
 static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
 {
     unsigned long flag = 0UL;
 
     ftrace_bug_type = FTRACE_BUG_UNKNOWN;
 
     if (rec->flags & FTRACE_FL_DISABLED)
         return FTRACE_UPDATE_IGNORE;
 
     /*
      * If we are updating calls:
      *
      *   If the record has a ref count, then we need to enable it
      *   because someone is using it.
      *
      *   Otherwise we make sure its disabled.
      *
      * If we are disabling calls, then disable all records that
      * are enabled.
      */
     if (enable && ftrace_rec_count(rec))
         flag = FTRACE_FL_ENABLED;
 
     /*
      * If enabling and the REGS flag does not match the REGS_EN, or
      * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
      * this record. Set flags to fail the compare against ENABLED.
      * Same for direct calls.
      */
     if (flag) {
         if (!(rec->flags & FTRACE_FL_REGS) !=
             !(rec->flags & FTRACE_FL_REGS_EN))
             flag |= FTRACE_FL_REGS;
 
         if (!(rec->flags & FTRACE_FL_TRAMP) !=
             !(rec->flags & FTRACE_FL_TRAMP_EN))
             flag |= FTRACE_FL_TRAMP;
 
         /*
          * Direct calls are special, as count matters.
          * We must test the record for direct, if the
          * DIRECT and DIRECT_EN do not match, but only
          * if the count is 1. That's because, if the
          * count is something other than one, we do not
          * want the direct enabled (it will be done via the
          * direct helper). But if DIRECT_EN is set, and
          * the count is not one, we need to clear it.
          */
         if (ftrace_rec_count(rec) == 1) {
             if (!(rec->flags & FTRACE_FL_DIRECT) !=
                 !(rec->flags & FTRACE_FL_DIRECT_EN))
                 flag |= FTRACE_FL_DIRECT;
         } else if (rec->flags & FTRACE_FL_DIRECT_EN) {
             flag |= FTRACE_FL_DIRECT;
         }
     }
 
     /* If the state of this record hasn't changed, then do nothing */
     if ((rec->flags & FTRACE_FL_ENABLED) == flag)
         return FTRACE_UPDATE_IGNORE;
 
     if (flag) {
         /* Save off if rec is being enabled (for return value) */
         flag ^= rec->flags & FTRACE_FL_ENABLED;
 
         if (update) {
             rec->flags |= FTRACE_FL_ENABLED;
             if (flag & FTRACE_FL_REGS) {
                 if (rec->flags & FTRACE_FL_REGS)
                     rec->flags |= FTRACE_FL_REGS_EN;
                 else
                     rec->flags &= ~FTRACE_FL_REGS_EN;
             }
             if (flag & FTRACE_FL_TRAMP) {
                 if (rec->flags & FTRACE_FL_TRAMP)
                     rec->flags |= FTRACE_FL_TRAMP_EN;
                 else
                     rec->flags &= ~FTRACE_FL_TRAMP_EN;
             }
 
             if (flag & FTRACE_FL_DIRECT) {
                 /*
                  * If there's only one user (direct_ops helper)
                  * then we can call the direct function
                  * directly (no ftrace trampoline).
                  */
                 if (ftrace_rec_count(rec) == 1) {
                     if (rec->flags & FTRACE_FL_DIRECT)
                         rec->flags |= FTRACE_FL_DIRECT_EN;
                     else
                         rec->flags &= ~FTRACE_FL_DIRECT_EN;
                 } else {
                     /*
                      * Can only call directly if there's
                      * only one callback to the function.
                      */
                     rec->flags &= ~FTRACE_FL_DIRECT_EN;
                 }
             }
         }
 
         /*
          * If this record is being updated from a nop, then
          *   return UPDATE_MAKE_CALL.
          * Otherwise,
          *   return UPDATE_MODIFY_CALL to tell the caller to convert
          *   from the save regs, to a non-save regs function or
          *   vice versa, or from a trampoline call.
          */
         if (flag & FTRACE_FL_ENABLED) {
             ftrace_bug_type = FTRACE_BUG_CALL;
             return FTRACE_UPDATE_MAKE_CALL;
         }
 
         ftrace_bug_type = FTRACE_BUG_UPDATE;
         return FTRACE_UPDATE_MODIFY_CALL;
     }
 
     if (update) {
         /* If there's no more users, clear all flags */
         if (!ftrace_rec_count(rec))
             rec->flags = 0;
         else
             /*
              * Just disable the record, but keep the ops TRAMP
              * and REGS states. The _EN flags must be disabled though.
              */
             rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
                     FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
     }
 
     ftrace_bug_type = FTRACE_BUG_NOP;
     return FTRACE_UPDATE_MAKE_NOP;
 }
 
 /**
  * ftrace_update_record - set a record that now is tracing or not
  * @rec: the record to update
  * @enable: set to true if the record is tracing, false to force disable
  *
  * The records that represent all functions that can be traced need
  * to be updated when tracing has been enabled.
  */
 int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
 {
     return ftrace_check_record(rec, enable, true);
 }
 
 /**
  * ftrace_test_record - check if the record has been enabled or not
  * @rec: the record to test
  * @enable: set to true to check if enabled, false if it is disabled
  *
  * The arch code may need to test if a record is already set to
  * tracing to determine how to modify the function code that it
  * represents.
  */
 int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
 {
     return ftrace_check_record(rec, enable, false);
 }
 
 static struct ftrace_ops *
 ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
 {
     struct ftrace_ops *op;
     unsigned long ip = rec->ip;
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
 
         if (!op->trampoline)
             continue;
 
         if (hash_contains_ip(ip, op->func_hash))
             return op;
     } while_for_each_ftrace_op(op);
 
     return NULL;
 }
 
 static struct ftrace_ops *
 ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
 {
     struct ftrace_ops *op;
     unsigned long ip = rec->ip;
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
 
         if (op == op_exclude || !op->trampoline)
             continue;
 
         if (hash_contains_ip(ip, op->func_hash))
             return op;
     } while_for_each_ftrace_op(op);
 
     return NULL;
 }
 
 static struct ftrace_ops *
 ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
                struct ftrace_ops *op)
 {
     unsigned long ip = rec->ip;
 
     while_for_each_ftrace_op(op) {
 
         if (!op->trampoline)
             continue;
 
         if (hash_contains_ip(ip, op->func_hash))
             return op;
     }
 
     return NULL;
 }
 
 static struct ftrace_ops *
 ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
 {
     struct ftrace_ops *op;
     unsigned long ip = rec->ip;
 
     /*
      * Need to check removed ops first.
      * If they are being removed, and this rec has a tramp,
      * and this rec is in the ops list, then it would be the
      * one with the tramp.
      */
     if (removed_ops) {
         if (hash_contains_ip(ip, &removed_ops->old_hash))
             return removed_ops;
     }
 
     /*
      * Need to find the current trampoline for a rec.
      * Now, a trampoline is only attached to a rec if there
      * was a single 'ops' attached to it. But this can be called
      * when we are adding another op to the rec or removing the
      * current one. Thus, if the op is being added, we can
      * ignore it because it hasn't attached itself to the rec
      * yet.
      *
      * If an ops is being modified (hooking to different functions)
      * then we don't care about the new functions that are being
      * added, just the old ones (that are probably being removed).
      *
      * If we are adding an ops to a function that already is using
      * a trampoline, it needs to be removed (trampolines are only
      * for single ops connected), then an ops that is not being
      * modified also needs to be checked.
      */
     do_for_each_ftrace_op(op, ftrace_ops_list) {
 
         if (!op->trampoline)
             continue;
 
         /*
          * If the ops is being added, it hasn't gotten to
          * the point to be removed from this tree yet.
          */
         if (op->flags & FTRACE_OPS_FL_ADDING)
             continue;
 
 
         /*
          * If the ops is being modified and is in the old
          * hash, then it is probably being removed from this
          * function.
          */
         if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
             hash_contains_ip(ip, &op->old_hash))
             return op;
         /*
          * If the ops is not being added or modified, and it's
          * in its normal filter hash, then this must be the one
          * we want!
          */
         if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
             hash_contains_ip(ip, op->func_hash))
             return op;
 
     } while_for_each_ftrace_op(op);
 
     return NULL;
 }
 
 static struct ftrace_ops *
 ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
 {
     struct ftrace_ops *op;
     unsigned long ip = rec->ip;
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
         /* pass rec in as regs to have non-NULL val */
         if (hash_contains_ip(ip, op->func_hash))
             return op;
     } while_for_each_ftrace_op(op);
 
     return NULL;
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 /* Protected by rcu_tasks for reading, and direct_mutex for writing */
 static struct ftrace_hash *direct_functions = EMPTY_HASH;
 static DEFINE_MUTEX(direct_mutex);
 int ftrace_direct_func_count;
 
 /*
  * Search the direct_functions hash to see if the given instruction pointer
  * has a direct caller attached to it.
  */
 unsigned long ftrace_find_rec_direct(unsigned long ip)
 {
     struct ftrace_func_entry *entry;
 
     entry = __ftrace_lookup_ip(direct_functions, ip);
     if (!entry)
         return 0;
 
     return entry->direct;
 }
 
 static struct ftrace_func_entry*
 ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
               struct ftrace_hash **free_hash)
 {
     struct ftrace_func_entry *entry;
 
     if (ftrace_hash_empty(direct_functions) ||
         direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
         struct ftrace_hash *new_hash;
         int size = ftrace_hash_empty(direct_functions) ? 0 :
             direct_functions->count + 1;
 
         if (size < 32)
             size = 32;
 
         new_hash = dup_hash(direct_functions, size);
         if (!new_hash)
             return NULL;
 
         *free_hash = direct_functions;
         direct_functions = new_hash;
     }
 
     entry = kmalloc(sizeof(*entry), GFP_KERNEL);
     if (!entry)
         return NULL;
 
     entry->ip = ip;
     entry->direct = addr;
     __add_hash_entry(direct_functions, entry);
     return entry;
 }
 
 static void call_direct_funcs(unsigned long ip, unsigned long pip,
                   struct ftrace_ops *ops, struct ftrace_regs *fregs)
 {
     struct pt_regs *regs = ftrace_get_regs(fregs);
     unsigned long addr;
 
     addr = ftrace_find_rec_direct(ip);
     if (!addr)
         return;
 
     arch_ftrace_set_direct_caller(regs, addr);
 }
 
 struct ftrace_ops direct_ops = {
     .func       = call_direct_funcs,
     .flags      = FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
               | FTRACE_OPS_FL_PERMANENT,
     /*
      * By declaring the main trampoline as this trampoline
      * it will never have one allocated for it. Allocated
      * trampolines should not call direct functions.
      * The direct_ops should only be called by the builtin
      * ftrace_regs_caller trampoline.
      */
     .trampoline = FTRACE_REGS_ADDR,
 };
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 /**
  * ftrace_get_addr_new - Get the call address to set to
  * @rec:  The ftrace record descriptor
  *
  * If the record has the FTRACE_FL_REGS set, that means that it
  * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
  * is not set, then it wants to convert to the normal callback.
  *
  * Returns the address of the trampoline to set to
  */
 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
 {
     struct ftrace_ops *ops;
     unsigned long addr;
 
     if ((rec->flags & FTRACE_FL_DIRECT) &&
         (ftrace_rec_count(rec) == 1)) {
         addr = ftrace_find_rec_direct(rec->ip);
         if (addr)
             return addr;
         WARN_ON_ONCE(1);
     }
 
     /* Trampolines take precedence over regs */
     if (rec->flags & FTRACE_FL_TRAMP) {
         ops = ftrace_find_tramp_ops_new(rec);
         if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
             pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
                 (void *)rec->ip, (void *)rec->ip, rec->flags);
             /* Ftrace is shutting down, return anything */
             return (unsigned long)FTRACE_ADDR;
         }
         return ops->trampoline;
     }
 
     if (rec->flags & FTRACE_FL_REGS)
         return (unsigned long)FTRACE_REGS_ADDR;
     else
         return (unsigned long)FTRACE_ADDR;
 }
 
 /**
  * ftrace_get_addr_curr - Get the call address that is already there
  * @rec:  The ftrace record descriptor
  *
  * The FTRACE_FL_REGS_EN is set when the record already points to
  * a function that saves all the regs. Basically the '_EN' version
  * represents the current state of the function.
  *
  * Returns the address of the trampoline that is currently being called
  */
 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
 {
     struct ftrace_ops *ops;
     unsigned long addr;
 
     /* Direct calls take precedence over trampolines */
     if (rec->flags & FTRACE_FL_DIRECT_EN) {
         addr = ftrace_find_rec_direct(rec->ip);
         if (addr)
             return addr;
         WARN_ON_ONCE(1);
     }
 
     /* Trampolines take precedence over regs */
     if (rec->flags & FTRACE_FL_TRAMP_EN) {
         ops = ftrace_find_tramp_ops_curr(rec);
         if (FTRACE_WARN_ON(!ops)) {
             pr_warn("Bad trampoline accounting at: %p (%pS)\n",
                 (void *)rec->ip, (void *)rec->ip);
             /* Ftrace is shutting down, return anything */
             return (unsigned long)FTRACE_ADDR;
         }
         return ops->trampoline;
     }
 
     if (rec->flags & FTRACE_FL_REGS_EN)
         return (unsigned long)FTRACE_REGS_ADDR;
     else
         return (unsigned long)FTRACE_ADDR;
 }
 
 static int
 __ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
 {
     unsigned long ftrace_old_addr;
     unsigned long ftrace_addr;
     int ret;
 
     ftrace_addr = ftrace_get_addr_new(rec);
 
     /* This needs to be done before we call ftrace_update_record */
     ftrace_old_addr = ftrace_get_addr_curr(rec);
 
     ret = ftrace_update_record(rec, enable);
 
     ftrace_bug_type = FTRACE_BUG_UNKNOWN;
 
     switch (ret) {
     case FTRACE_UPDATE_IGNORE:
         return 0;
 
     case FTRACE_UPDATE_MAKE_CALL:
         ftrace_bug_type = FTRACE_BUG_CALL;
         return ftrace_make_call(rec, ftrace_addr);
 
     case FTRACE_UPDATE_MAKE_NOP:
         ftrace_bug_type = FTRACE_BUG_NOP;
         return ftrace_make_nop(NULL, rec, ftrace_old_addr);
 
     case FTRACE_UPDATE_MODIFY_CALL:
         ftrace_bug_type = FTRACE_BUG_UPDATE;
         return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
     }
 
     return -1; /* unknown ftrace bug */
 }
 
 void __weak ftrace_replace_code(int mod_flags)
 {
     struct dyn_ftrace *rec;
     struct ftrace_page *pg;
     bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
     int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
     int failed;
 
     if (unlikely(ftrace_disabled))
         return;
 
     do_for_each_ftrace_rec(pg, rec) {
 
         if (rec->flags & FTRACE_FL_DISABLED)
             continue;
 
         failed = __ftrace_replace_code(rec, enable);
         if (failed) {
             ftrace_bug(failed, rec);
             /* Stop processing */
             return;
         }
         if (schedulable)
             cond_resched();
     } while_for_each_ftrace_rec();
 }
 
 struct ftrace_rec_iter {
     struct ftrace_page  *pg;
     int         index;
 };
 
 /**
  * ftrace_rec_iter_start - start up iterating over traced functions
  *
  * Returns an iterator handle that is used to iterate over all
  * the records that represent address locations where functions
  * are traced.
  *
  * May return NULL if no records are available.
  */
 struct ftrace_rec_iter *ftrace_rec_iter_start(void)
 {
     /*
      * We only use a single iterator.
      * Protected by the ftrace_lock mutex.
      */
     static struct ftrace_rec_iter ftrace_rec_iter;
     struct ftrace_rec_iter *iter = &ftrace_rec_iter;
 
     iter->pg = ftrace_pages_start;
     iter->index = 0;
 
     /* Could have empty pages */
     while (iter->pg && !iter->pg->index)
         iter->pg = iter->pg->next;
 
     if (!iter->pg)
         return NULL;
 
     return iter;
 }
 
 /**
  * ftrace_rec_iter_next - get the next record to process.
  * @iter: The handle to the iterator.
  *
  * Returns the next iterator after the given iterator @iter.
  */
 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
 {
     iter->index++;
 
     if (iter->index >= iter->pg->index) {
         iter->pg = iter->pg->next;
         iter->index = 0;
 
         /* Could have empty pages */
         while (iter->pg && !iter->pg->index)
             iter->pg = iter->pg->next;
     }
 
     if (!iter->pg)
         return NULL;
 
     return iter;
 }
 
 /**
  * ftrace_rec_iter_record - get the record at the iterator location
  * @iter: The current iterator location
  *
  * Returns the record that the current @iter is at.
  */
 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
 {
     return &iter->pg->records[iter->index];
 }
 
 static int
 ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
 {
     int ret;
 
     if (unlikely(ftrace_disabled))
         return 0;
 
     ret = ftrace_init_nop(mod, rec);
     if (ret) {
         ftrace_bug_type = FTRACE_BUG_INIT;
         ftrace_bug(ret, rec);
         return 0;
     }
     return 1;
 }
 
 /*
  * archs can override this function if they must do something
  * before the modifying code is performed.
  */
 void __weak ftrace_arch_code_modify_prepare(void)
 {
 }
 
 /*
  * archs can override this function if they must do something
  * after the modifying code is performed.
  */
 void __weak ftrace_arch_code_modify_post_process(void)
 {
 }
 
 void ftrace_modify_all_code(int command)
 {
     int update = command & FTRACE_UPDATE_TRACE_FUNC;
     int mod_flags = 0;
     int err = 0;
 
     if (command & FTRACE_MAY_SLEEP)
         mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
 
     /*
      * If the ftrace_caller calls a ftrace_ops func directly,
      * we need to make sure that it only traces functions it
      * expects to trace. When doing the switch of functions,
      * we need to update to the ftrace_ops_list_func first
      * before the transition between old and new calls are set,
      * as the ftrace_ops_list_func will check the ops hashes
      * to make sure the ops are having the right functions
      * traced.
      */
     if (update) {
         err = ftrace_update_ftrace_func(ftrace_ops_list_func);
         if (FTRACE_WARN_ON(err))
             return;
     }
 
     if (command & FTRACE_UPDATE_CALLS)
         ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
     else if (command & FTRACE_DISABLE_CALLS)
         ftrace_replace_code(mod_flags);
 
     if (update && ftrace_trace_function != ftrace_ops_list_func) {
         function_trace_op = set_function_trace_op;
         smp_wmb();
         /* If irqs are disabled, we are in stop machine */
         if (!irqs_disabled())
             smp_call_function(ftrace_sync_ipi, NULL, 1);
         err = ftrace_update_ftrace_func(ftrace_trace_function);
         if (FTRACE_WARN_ON(err))
             return;
     }
 
     if (command & FTRACE_START_FUNC_RET)
         err = ftrace_enable_ftrace_graph_caller();
     else if (command & FTRACE_STOP_FUNC_RET)
         err = ftrace_disable_ftrace_graph_caller();
     FTRACE_WARN_ON(err);
 }
 
 static int __ftrace_modify_code(void *data)
 {
     int *command = data;
 
     ftrace_modify_all_code(*command);
 
     return 0;
 }
 
 /**
  * ftrace_run_stop_machine - go back to the stop machine method
  * @command: The command to tell ftrace what to do
  *
  * If an arch needs to fall back to the stop machine method, the
  * it can call this function.
  */
 void ftrace_run_stop_machine(int command)
 {
     stop_machine(__ftrace_modify_code, &command, NULL);
 }
 
 /**
  * arch_ftrace_update_code - modify the code to trace or not trace
  * @command: The command that needs to be done
  *
  * Archs can override this function if it does not need to
  * run stop_machine() to modify code.
  */
 void __weak arch_ftrace_update_code(int command)
 {
     ftrace_run_stop_machine(command);
 }
 
 static void ftrace_run_update_code(int command)
 {
     ftrace_arch_code_modify_prepare();
 
     /*
      * By default we use stop_machine() to modify the code.
      * But archs can do what ever they want as long as it
      * is safe. The stop_machine() is the safest, but also
      * produces the most overhead.
      */
     arch_ftrace_update_code(command);
 
     ftrace_arch_code_modify_post_process();
 }
 
 static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
                    struct ftrace_ops_hash *old_hash)
 {
     ops->flags |= FTRACE_OPS_FL_MODIFYING;
     ops->old_hash.filter_hash = old_hash->filter_hash;
     ops->old_hash.notrace_hash = old_hash->notrace_hash;
     ftrace_run_update_code(command);
     ops->old_hash.filter_hash = NULL;
     ops->old_hash.notrace_hash = NULL;
     ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
 }
 
 static ftrace_func_t saved_ftrace_func;
 static int ftrace_start_up;
 
 void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
 {
 }
 
 /* List of trace_ops that have allocated trampolines */
 static LIST_HEAD(ftrace_ops_trampoline_list);
 
 static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
 {
     lockdep_assert_held(&ftrace_lock);
     list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
 }
 
 static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
 {
     lockdep_assert_held(&ftrace_lock);
     list_del_rcu(&ops->list);
     synchronize_rcu();
 }
 
 /*
  * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
  * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
  * not a module.
  */
 #define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
 #define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
 
 static void ftrace_trampoline_free(struct ftrace_ops *ops)
 {
     if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
         ops->trampoline) {
         /*
          * Record the text poke event before the ksymbol unregister
          * event.
          */
         perf_event_text_poke((void *)ops->trampoline,
                      (void *)ops->trampoline,
                      ops->trampoline_size, NULL, 0);
         perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
                    ops->trampoline, ops->trampoline_size,
                    true, FTRACE_TRAMPOLINE_SYM);
         /* Remove from kallsyms after the perf events */
         ftrace_remove_trampoline_from_kallsyms(ops);
     }
 
     arch_ftrace_trampoline_free(ops);
 }
 
 static void ftrace_startup_enable(int command)
 {
     if (saved_ftrace_func != ftrace_trace_function) {
         saved_ftrace_func = ftrace_trace_function;
         command |= FTRACE_UPDATE_TRACE_FUNC;
     }
 
     if (!command || !ftrace_enabled)
         return;
 
     ftrace_run_update_code(command);
 }
 
 static void ftrace_startup_all(int command)
 {
     update_all_ops = true;
     ftrace_startup_enable(command);
     update_all_ops = false;
 }
 
 int ftrace_startup(struct ftrace_ops *ops, int command)
 {
     int ret;
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     ret = __register_ftrace_function(ops);
     if (ret)
         return ret;
 
     ftrace_start_up++;
 
     /*
      * Note that ftrace probes uses this to start up
      * and modify functions it will probe. But we still
      * set the ADDING flag for modification, as probes
      * do not have trampolines. If they add them in the
      * future, then the probes will need to distinguish
      * between adding and updating probes.
      */
     ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
 
     ret = ftrace_hash_ipmodify_enable(ops);
     if (ret < 0) {
         /* Rollback registration process */
         __unregister_ftrace_function(ops);
         ftrace_start_up--;
         ops->flags &= ~FTRACE_OPS_FL_ENABLED;
         if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
             ftrace_trampoline_free(ops);
         return ret;
     }
 
     if (ftrace_hash_rec_enable(ops, 1))
         command |= FTRACE_UPDATE_CALLS;
 
     ftrace_startup_enable(command);
 
     /*
      * If ftrace is in an undefined state, we just remove ops from list
      * to prevent the NULL pointer, instead of totally rolling it back and
      * free trampoline, because those actions could cause further damage.
      */
     if (unlikely(ftrace_disabled)) {
         __unregister_ftrace_function(ops);
         return -ENODEV;
     }
 
     ops->flags &= ~FTRACE_OPS_FL_ADDING;
 
     return 0;
 }
 
 int ftrace_shutdown(struct ftrace_ops *ops, int command)
 {
     int ret;
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     ret = __unregister_ftrace_function(ops);
     if (ret)
         return ret;
 
     ftrace_start_up--;
     /*
      * Just warn in case of unbalance, no need to kill ftrace, it's not
      * critical but the ftrace_call callers may be never nopped again after
      * further ftrace uses.
      */
     WARN_ON_ONCE(ftrace_start_up < 0);
 
     /* Disabling ipmodify never fails */
     ftrace_hash_ipmodify_disable(ops);
 
     if (ftrace_hash_rec_disable(ops, 1))
         command |= FTRACE_UPDATE_CALLS;
 
     ops->flags &= ~FTRACE_OPS_FL_ENABLED;
 
     if (saved_ftrace_func != ftrace_trace_function) {
         saved_ftrace_func = ftrace_trace_function;
         command |= FTRACE_UPDATE_TRACE_FUNC;
     }
 
     if (!command || !ftrace_enabled) {
         /*
          * If these are dynamic or per_cpu ops, they still
          * need their data freed. Since, function tracing is
          * not currently active, we can just free them
          * without synchronizing all CPUs.
          */
         if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
             goto free_ops;
 
         return 0;
     }
 
     /*
      * If the ops uses a trampoline, then it needs to be
      * tested first on update.
      */
     ops->flags |= FTRACE_OPS_FL_REMOVING;
     removed_ops = ops;
 
     /* The trampoline logic checks the old hashes */
     ops->old_hash.filter_hash = ops->func_hash->filter_hash;
     ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
 
     ftrace_run_update_code(command);
 
     /*
      * If there's no more ops registered with ftrace, run a
      * sanity check to make sure all rec flags are cleared.
      */
     if (rcu_dereference_protected(ftrace_ops_list,
             lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
         struct ftrace_page *pg;
         struct dyn_ftrace *rec;
 
         do_for_each_ftrace_rec(pg, rec) {
             if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
                 pr_warn("  %pS flags:%lx\n",
                     (void *)rec->ip, rec->flags);
         } while_for_each_ftrace_rec();
     }
 
     ops->old_hash.filter_hash = NULL;
     ops->old_hash.notrace_hash = NULL;
 
     removed_ops = NULL;
     ops->flags &= ~FTRACE_OPS_FL_REMOVING;
 
     /*
      * Dynamic ops may be freed, we must make sure that all
      * callers are done before leaving this function.
      * The same goes for freeing the per_cpu data of the per_cpu
      * ops.
      */
     if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
         /*
          * We need to do a hard force of sched synchronization.
          * This is because we use preempt_disable() to do RCU, but
          * the function tracers can be called where RCU is not watching
          * (like before user_exit()). We can not rely on the RCU
          * infrastructure to do the synchronization, thus we must do it
          * ourselves.
          */
         synchronize_rcu_tasks_rude();
 
         /*
          * When the kernel is preemptive, tasks can be preempted
          * while on a ftrace trampoline. Just scheduling a task on
          * a CPU is not good enough to flush them. Calling
          * synchronize_rcu_tasks() will wait for those tasks to
          * execute and either schedule voluntarily or enter user space.
          */
         if (IS_ENABLED(CONFIG_PREEMPTION))
             synchronize_rcu_tasks();
 
  free_ops:
         ftrace_trampoline_free(ops);
     }
 
     return 0;
 }
 
 static u64      ftrace_update_time;
 unsigned long       ftrace_update_tot_cnt;
 unsigned long       ftrace_number_of_pages;
 unsigned long       ftrace_number_of_groups;
 
 static inline int ops_traces_mod(struct ftrace_ops *ops)
 {
     /*
      * Filter_hash being empty will default to trace module.
      * But notrace hash requires a test of individual module functions.
      */
     return ftrace_hash_empty(ops->func_hash->filter_hash) &&
         ftrace_hash_empty(ops->func_hash->notrace_hash);
 }
 
 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
 {
     bool init_nop = ftrace_need_init_nop();
     struct ftrace_page *pg;
     struct dyn_ftrace *p;
     u64 start, stop;
     unsigned long update_cnt = 0;
     unsigned long rec_flags = 0;
     int i;
 
     start = ftrace_now(raw_smp_processor_id());
 
     /*
      * When a module is loaded, this function is called to convert
      * the calls to mcount in its text to nops, and also to create
      * an entry in the ftrace data. Now, if ftrace is activated
      * after this call, but before the module sets its text to
      * read-only, the modification of enabling ftrace can fail if
      * the read-only is done while ftrace is converting the calls.
      * To prevent this, the module's records are set as disabled
      * and will be enabled after the call to set the module's text
      * to read-only.
      */
     if (mod)
         rec_flags |= FTRACE_FL_DISABLED;
 
     for (pg = new_pgs; pg; pg = pg->next) {
 
         for (i = 0; i < pg->index; i++) {
 
             /* If something went wrong, bail without enabling anything */
             if (unlikely(ftrace_disabled))
                 return -1;
 
             p = &pg->records[i];
             p->flags = rec_flags;
 
             /*
              * Do the initial record conversion from mcount jump
              * to the NOP instructions.
              */
             if (init_nop && !ftrace_nop_initialize(mod, p))
                 break;
 
             update_cnt++;
         }
     }
 
     stop = ftrace_now(raw_smp_processor_id());
     ftrace_update_time = stop - start;
     ftrace_update_tot_cnt += update_cnt;
 
     return 0;
 }
 
 static int ftrace_allocate_records(struct ftrace_page *pg, int count)
 {
     int order;
     int pages;
     int cnt;
 
     if (WARN_ON(!count))
         return -EINVAL;
 
     /* We want to fill as much as possible, with no empty pages */
     pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
     order = fls(pages) - 1;
 
  again:
     pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
 
     if (!pg->records) {
         /* if we can't allocate this size, try something smaller */
         if (!order)
             return -ENOMEM;
         order >>= 1;
         goto again;
     }
 
     ftrace_number_of_pages += 1 << order;
     ftrace_number_of_groups++;
 
     cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
     pg->order = order;
 
     if (cnt > count)
         cnt = count;
 
     return cnt;
 }
 
 static struct ftrace_page *
 ftrace_allocate_pages(unsigned long num_to_init)
 {
     struct ftrace_page *start_pg;
     struct ftrace_page *pg;
     int cnt;
 
     if (!num_to_init)
         return NULL;
 
     start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
     if (!pg)
         return NULL;
 
     /*
      * Try to allocate as much as possible in one continues
      * location that fills in all of the space. We want to
      * waste as little space as possible.
      */
     for (;;) {
         cnt = ftrace_allocate_records(pg, num_to_init);
         if (cnt < 0)
             goto free_pages;
 
         num_to_init -= cnt;
         if (!num_to_init)
             break;
 
         pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
         if (!pg->next)
             goto free_pages;
 
         pg = pg->next;
     }
 
     return start_pg;
 
  free_pages:
     pg = start_pg;
     while (pg) {
         if (pg->records) {
             free_pages((unsigned long)pg->records, pg->order);
             ftrace_number_of_pages -= 1 << pg->order;
         }
         start_pg = pg->next;
         kfree(pg);
         pg = start_pg;
         ftrace_number_of_groups--;
     }
     pr_info("ftrace: FAILED to allocate memory for functions\n");
     return NULL;
 }
 
 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 
 struct ftrace_iterator {
     loff_t              pos;
     loff_t              func_pos;
     loff_t              mod_pos;
     struct ftrace_page      *pg;
     struct dyn_ftrace       *func;
     struct ftrace_func_probe    *probe;
     struct ftrace_func_entry    *probe_entry;
     struct trace_parser     parser;
     struct ftrace_hash      *hash;
     struct ftrace_ops       *ops;
     struct trace_array      *tr;
     struct list_head        *mod_list;
     int             pidx;
     int             idx;
     unsigned            flags;
 };
 
 static void *
 t_probe_next(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_iterator *iter = m->private;
     struct trace_array *tr = iter->ops->private;
     struct list_head *func_probes;
     struct ftrace_hash *hash;
     struct list_head *next;
     struct hlist_node *hnd = NULL;
     struct hlist_head *hhd;
     int size;
 
     (*pos)++;
     iter->pos = *pos;
 
     if (!tr)
         return NULL;
 
     func_probes = &tr->func_probes;
     if (list_empty(func_probes))
         return NULL;
 
     if (!iter->probe) {
         next = func_probes->next;
         iter->probe = list_entry(next, struct ftrace_func_probe, list);
     }
 
     if (iter->probe_entry)
         hnd = &iter->probe_entry->hlist;
 
     hash = iter->probe->ops.func_hash->filter_hash;
 
     /*
      * A probe being registered may temporarily have an empty hash
      * and it's at the end of the func_probes list.
      */
     if (!hash || hash == EMPTY_HASH)
         return NULL;
 
     size = 1 << hash->size_bits;
 
  retry:
     if (iter->pidx >= size) {
         if (iter->probe->list.next == func_probes)
             return NULL;
         next = iter->probe->list.next;
         iter->probe = list_entry(next, struct ftrace_func_probe, list);
         hash = iter->probe->ops.func_hash->filter_hash;
         size = 1 << hash->size_bits;
         iter->pidx = 0;
     }
 
     hhd = &hash->buckets[iter->pidx];
 
     if (hlist_empty(hhd)) {
         iter->pidx++;
         hnd = NULL;
         goto retry;
     }
 
     if (!hnd)
         hnd = hhd->first;
     else {
         hnd = hnd->next;
         if (!hnd) {
             iter->pidx++;
             goto retry;
         }
     }
 
     if (WARN_ON_ONCE(!hnd))
         return NULL;
 
     iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
 
     return iter;
 }
 
 static void *t_probe_start(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_iterator *iter = m->private;
     void *p = NULL;
     loff_t l;
 
     if (!(iter->flags & FTRACE_ITER_DO_PROBES))
         return NULL;
 
     if (iter->mod_pos > *pos)
         return NULL;
 
     iter->probe = NULL;
     iter->probe_entry = NULL;
     iter->pidx = 0;
     for (l = 0; l <= (*pos - iter->mod_pos); ) {
         p = t_probe_next(m, &l);
         if (!p)
             break;
     }
     if (!p)
         return NULL;
 
     /* Only set this if we have an item */
     iter->flags |= FTRACE_ITER_PROBE;
 
     return iter;
 }
 
 static int
 t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
 {
     struct ftrace_func_entry *probe_entry;
     struct ftrace_probe_ops *probe_ops;
     struct ftrace_func_probe *probe;
 
     probe = iter->probe;
     probe_entry = iter->probe_entry;
 
     if (WARN_ON_ONCE(!probe || !probe_entry))
         return -EIO;
 
     probe_ops = probe->probe_ops;
 
     if (probe_ops->print)
         return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
 
     seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
            (void *)probe_ops->func);
 
     return 0;
 }
 
 static void *
 t_mod_next(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_iterator *iter = m->private;
     struct trace_array *tr = iter->tr;
 
     (*pos)++;
     iter->pos = *pos;
 
     iter->mod_list = iter->mod_list->next;
 
     if (iter->mod_list == &tr->mod_trace ||
         iter->mod_list == &tr->mod_notrace) {
         iter->flags &= ~FTRACE_ITER_MOD;
         return NULL;
     }
 
     iter->mod_pos = *pos;
 
     return iter;
 }
 
 static void *t_mod_start(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_iterator *iter = m->private;
     void *p = NULL;
     loff_t l;
 
     if (iter->func_pos > *pos)
         return NULL;
 
     iter->mod_pos = iter->func_pos;
 
     /* probes are only available if tr is set */
     if (!iter->tr)
         return NULL;
 
     for (l = 0; l <= (*pos - iter->func_pos); ) {
         p = t_mod_next(m, &l);
         if (!p)
             break;
     }
     if (!p) {
         iter->flags &= ~FTRACE_ITER_MOD;
         return t_probe_start(m, pos);
     }
 
     /* Only set this if we have an item */
     iter->flags |= FTRACE_ITER_MOD;
 
     return iter;
 }
 
 static int
 t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
 {
     struct ftrace_mod_load *ftrace_mod;
     struct trace_array *tr = iter->tr;
 
     if (WARN_ON_ONCE(!iter->mod_list) ||
              iter->mod_list == &tr->mod_trace ||
              iter->mod_list == &tr->mod_notrace)
         return -EIO;
 
     ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
 
     if (ftrace_mod->func)
         seq_printf(m, "%s", ftrace_mod->func);
     else
         seq_putc(m, '*');
 
     seq_printf(m, ":mod:%s\n", ftrace_mod->module);
 
     return 0;
 }
 
 static void *
 t_func_next(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_iterator *iter = m->private;
     struct dyn_ftrace *rec = NULL;
 
     (*pos)++;
 
  retry:
     if (iter->idx >= iter->pg->index) {
         if (iter->pg->next) {
             iter->pg = iter->pg->next;
             iter->idx = 0;
             goto retry;
         }
     } else {
         rec = &iter->pg->records[iter->idx++];
         if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
              !ftrace_lookup_ip(iter->hash, rec->ip)) ||
 
             ((iter->flags & FTRACE_ITER_ENABLED) &&
              !(rec->flags & FTRACE_FL_ENABLED))) {
 
             rec = NULL;
             goto retry;
         }
     }
 
     if (!rec)
         return NULL;
 
     iter->pos = iter->func_pos = *pos;
     iter->func = rec;
 
     return iter;
 }
 
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
     struct ftrace_iterator *iter = m->private;
     loff_t l = *pos; /* t_probe_start() must use original pos */
     void *ret;
 
     if (unlikely(ftrace_disabled))
         return NULL;
 
     if (iter->flags & FTRACE_ITER_PROBE)
         return t_probe_next(m, pos);
 
     if (iter->flags & FTRACE_ITER_MOD)
         return t_mod_next(m, pos);
 
     if (iter->flags & FTRACE_ITER_PRINTALL) {
         /* next must increment pos, and t_probe_start does not */
         (*pos)++;
         return t_mod_start(m, &l);
     }
 
     ret = t_func_next(m, pos);
 
     if (!ret)
         return t_mod_start(m, &l);
 
     return ret;
 }
 
 static void reset_iter_read(struct ftrace_iterator *iter)
 {
     iter->pos = 0;
     iter->func_pos = 0;
     iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_iterator *iter = m->private;
     void *p = NULL;
     loff_t l;
 
     mutex_lock(&ftrace_lock);
 
     if (unlikely(ftrace_disabled))
         return NULL;
 
     /*
      * If an lseek was done, then reset and start from beginning.
      */
     if (*pos < iter->pos)
         reset_iter_read(iter);
 
     /*
      * For set_ftrace_filter reading, if we have the filter
      * off, we can short cut and just print out that all
      * functions are enabled.
      */
     if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
         ftrace_hash_empty(iter->hash)) {
         iter->func_pos = 1; /* Account for the message */
         if (*pos > 0)
             return t_mod_start(m, pos);
         iter->flags |= FTRACE_ITER_PRINTALL;
         /* reset in case of seek/pread */
         iter->flags &= ~FTRACE_ITER_PROBE;
         return iter;
     }
 
     if (iter->flags & FTRACE_ITER_MOD)
         return t_mod_start(m, pos);
 
     /*
      * Unfortunately, we need to restart at ftrace_pages_start
      * every time we let go of the ftrace_mutex. This is because
      * those pointers can change without the lock.
      */
     iter->pg = ftrace_pages_start;
     iter->idx = 0;
     for (l = 0; l <= *pos; ) {
         p = t_func_next(m, &l);
         if (!p)
             break;
     }
 
     if (!p)
         return t_mod_start(m, pos);
 
     return iter;
 }
 
 static void t_stop(struct seq_file *m, void *p)
 {
     mutex_unlock(&ftrace_lock);
 }
 
 void * __weak
 arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
 {
     return NULL;
 }
 
 static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
                 struct dyn_ftrace *rec)
 {
     void *ptr;
 
     ptr = arch_ftrace_trampoline_func(ops, rec);
     if (ptr)
         seq_printf(m, " ->%pS", ptr);
 }
 
 #ifdef FTRACE_MCOUNT_MAX_OFFSET
 /*
  * Weak functions can still have an mcount/fentry that is saved in
  * the __mcount_loc section. These can be detected by having a
  * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
  * symbol found by kallsyms is not the function that the mcount/fentry
  * is part of. The offset is much greater in these cases.
  *
  * Test the record to make sure that the ip points to a valid kallsyms
  * and if not, mark it disabled.
  */
 static int test_for_valid_rec(struct dyn_ftrace *rec)
 {
     char str[KSYM_SYMBOL_LEN];
     unsigned long offset;
     const char *ret;
 
     ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
 
     /* Weak functions can cause invalid addresses */
     if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
         rec->flags |= FTRACE_FL_DISABLED;
         return 0;
     }
     return 1;
 }
 
 static struct workqueue_struct *ftrace_check_wq __initdata;
 static struct work_struct ftrace_check_work __initdata;
 
 /*
  * Scan all the mcount/fentry entries to make sure they are valid.
  */
 static __init void ftrace_check_work_func(struct work_struct *work)
 {
     struct ftrace_page *pg;
     struct dyn_ftrace *rec;
 
     mutex_lock(&ftrace_lock);
     do_for_each_ftrace_rec(pg, rec) {
         test_for_valid_rec(rec);
     } while_for_each_ftrace_rec();
     mutex_unlock(&ftrace_lock);
 }
 
 static int __init ftrace_check_for_weak_functions(void)
 {
     INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
 
     ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
 
     queue_work(ftrace_check_wq, &ftrace_check_work);
     return 0;
 }
 
 static int __init ftrace_check_sync(void)
 {
     /* Make sure the ftrace_check updates are finished */
     if (ftrace_check_wq)
         destroy_workqueue(ftrace_check_wq);
     return 0;
 }
 
 late_initcall_sync(ftrace_check_sync);
 subsys_initcall(ftrace_check_for_weak_functions);
 
 static int print_rec(struct seq_file *m, unsigned long ip)
 {
     unsigned long offset;
     char str[KSYM_SYMBOL_LEN];
     char *modname;
     const char *ret;
 
     ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
     /* Weak functions can cause invalid addresses */
     if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
         snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
              FTRACE_INVALID_FUNCTION, offset);
         ret = NULL;
     }
 
     seq_puts(m, str);
     if (modname)
         seq_printf(m, " [%s]", modname);
     return ret == NULL ? -1 : 0;
 }
 #else
 static inline int test_for_valid_rec(struct dyn_ftrace *rec)
 {
     return 1;
 }
 
 static inline int print_rec(struct seq_file *m, unsigned long ip)
 {
     seq_printf(m, "%ps", (void *)ip);
     return 0;
 }
 #endif
 
 static int t_show(struct seq_file *m, void *v)
 {
     struct ftrace_iterator *iter = m->private;
     struct dyn_ftrace *rec;
 
     if (iter->flags & FTRACE_ITER_PROBE)
         return t_probe_show(m, iter);
 
     if (iter->flags & FTRACE_ITER_MOD)
         return t_mod_show(m, iter);
 
     if (iter->flags & FTRACE_ITER_PRINTALL) {
         if (iter->flags & FTRACE_ITER_NOTRACE)
             seq_puts(m, "#### no functions disabled ####\n");
         else
             seq_puts(m, "#### all functions enabled ####\n");
         return 0;
     }
 
     rec = iter->func;
 
     if (!rec)
         return 0;
 
     if (print_rec(m, rec->ip)) {
         /* This should only happen when a rec is disabled */
         WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
         seq_putc(m, '\n');
         return 0;
     }
 
     if (iter->flags & FTRACE_ITER_ENABLED) {
         struct ftrace_ops *ops;
 
         seq_printf(m, " (%ld)%s%s%s",
                ftrace_rec_count(rec),
                rec->flags & FTRACE_FL_REGS ? " R" : "  ",
                rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
                rec->flags & FTRACE_FL_DIRECT ? " D" : "  ");
         if (rec->flags & FTRACE_FL_TRAMP_EN) {
             ops = ftrace_find_tramp_ops_any(rec);
             if (ops) {
                 do {
                     seq_printf(m, "\ttramp: %pS (%pS)",
                            (void *)ops->trampoline,
                            (void *)ops->func);
                     add_trampoline_func(m, ops, rec);
                     ops = ftrace_find_tramp_ops_next(rec, ops);
                 } while (ops);
             } else
                 seq_puts(m, "\ttramp: ERROR!");
         } else {
             add_trampoline_func(m, NULL, rec);
         }
         if (rec->flags & FTRACE_FL_DIRECT) {
             unsigned long direct;
 
             direct = ftrace_find_rec_direct(rec->ip);
             if (direct)
                 seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
         }
     }
 
     seq_putc(m, '\n');
 
     return 0;
 }
 
 static const struct seq_operations show_ftrace_seq_ops = {
     .start = t_start,
     .next = t_next,
     .stop = t_stop,
     .show = t_show,
 };
 
 static int
 ftrace_avail_open(struct inode *inode, struct file *file)
 {
     struct ftrace_iterator *iter;
     int ret;
 
     ret = security_locked_down(LOCKDOWN_TRACEFS);
     if (ret)
         return ret;
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
     if (!iter)
         return -ENOMEM;
 
     iter->pg = ftrace_pages_start;
     iter->ops = &global_ops;
 
     return 0;
 }
 
 static int
 ftrace_enabled_open(struct inode *inode, struct file *file)
 {
     struct ftrace_iterator *iter;
 
     /*
      * This shows us what functions are currently being
      * traced and by what. Not sure if we want lockdown
      * to hide such critical information for an admin.
      * Although, perhaps it can show information we don't
      * want people to see, but if something is tracing
      * something, we probably want to know about it.
      */
 
     iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
     if (!iter)
         return -ENOMEM;
 
     iter->pg = ftrace_pages_start;
     iter->flags = FTRACE_ITER_ENABLED;
     iter->ops = &global_ops;
 
     return 0;
 }
 
 /**
  * ftrace_regex_open - initialize function tracer filter files
  * @ops: The ftrace_ops that hold the hash filters
  * @flag: The type of filter to process
  * @inode: The inode, usually passed in to your open routine
  * @file: The file, usually passed in to your open routine
  *
  * ftrace_regex_open() initializes the filter files for the
  * @ops. Depending on @flag it may process the filter hash or
  * the notrace hash of @ops. With this called from the open
  * routine, you can use ftrace_filter_write() for the write
  * routine if @flag has FTRACE_ITER_FILTER set, or
  * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
  * tracing_lseek() should be used as the lseek routine, and
  * release must call ftrace_regex_release().
  */
 int
 ftrace_regex_open(struct ftrace_ops *ops, int flag,
           struct inode *inode, struct file *file)
 {
     struct ftrace_iterator *iter;
     struct ftrace_hash *hash;
     struct list_head *mod_head;
     struct trace_array *tr = ops->private;
     int ret = -ENOMEM;
 
     ftrace_ops_init(ops);
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     if (tracing_check_open_get_tr(tr))
         return -ENODEV;
 
     iter = kzalloc(sizeof(*iter), GFP_KERNEL);
     if (!iter)
         goto out;
 
     if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
         goto out;
 
     iter->ops = ops;
     iter->flags = flag;
     iter->tr = tr;
 
     mutex_lock(&ops->func_hash->regex_lock);
 
     if (flag & FTRACE_ITER_NOTRACE) {
         hash = ops->func_hash->notrace_hash;
         mod_head = tr ? &tr->mod_notrace : NULL;
     } else {
         hash = ops->func_hash->filter_hash;
         mod_head = tr ? &tr->mod_trace : NULL;
     }
 
     iter->mod_list = mod_head;
 
     if (file->f_mode & FMODE_WRITE) {
         const int size_bits = FTRACE_HASH_DEFAULT_BITS;
 
         if (file->f_flags & O_TRUNC) {
             iter->hash = alloc_ftrace_hash(size_bits);
             clear_ftrace_mod_list(mod_head);
             } else {
             iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
         }
 
         if (!iter->hash) {
             trace_parser_put(&iter->parser);
             goto out_unlock;
         }
     } else
         iter->hash = hash;
 
     ret = 0;
 
     if (file->f_mode & FMODE_READ) {
         iter->pg = ftrace_pages_start;
 
         ret = seq_open(file, &show_ftrace_seq_ops);
         if (!ret) {
             struct seq_file *m = file->private_data;
             m->private = iter;
         } else {
             /* Failed */
             free_ftrace_hash(iter->hash);
             trace_parser_put(&iter->parser);
         }
     } else
         file->private_data = iter;
 
  out_unlock:
     mutex_unlock(&ops->func_hash->regex_lock);
 
  out:
     if (ret) {
         kfree(iter);
         if (tr)
             trace_array_put(tr);
     }
 
     return ret;
 }
 
 static int
 ftrace_filter_open(struct inode *inode, struct file *file)
 {
     struct ftrace_ops *ops = inode->i_private;
 
     /* Checks for tracefs lockdown */
     return ftrace_regex_open(ops,
             FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
             inode, file);
 }
 
 static int
 ftrace_notrace_open(struct inode *inode, struct file *file)
 {
     struct ftrace_ops *ops = inode->i_private;
 
     /* Checks for tracefs lockdown */
     return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
                  inode, file);
 }
 
 /* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
 struct ftrace_glob {
     char *search;
     unsigned len;
     int type;
 };
 
 /*
  * If symbols in an architecture don't correspond exactly to the user-visible
  * name of what they represent, it is possible to define this function to
  * perform the necessary adjustments.
 */
 char * __weak arch_ftrace_match_adjust(char *str, const char *search)
 {
     return str;
 }
 
 static int ftrace_match(char *str, struct ftrace_glob *g)
 {
     int matched = 0;
     int slen;
 
     str = arch_ftrace_match_adjust(str, g->search);
 
     switch (g->type) {
     case MATCH_FULL:
         if (strcmp(str, g->search) == 0)
             matched = 1;
         break;
     case MATCH_FRONT_ONLY:
         if (strncmp(str, g->search, g->len) == 0)
             matched = 1;
         break;
     case MATCH_MIDDLE_ONLY:
         if (strstr(str, g->search))
             matched = 1;
         break;
     case MATCH_END_ONLY:
         slen = strlen(str);
         if (slen >= g->len &&
             memcmp(str + slen - g->len, g->search, g->len) == 0)
             matched = 1;
         break;
     case MATCH_GLOB:
         if (glob_match(g->search, str))
             matched = 1;
         break;
     }
 
     return matched;
 }
 
 static int
 enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
 {
     struct ftrace_func_entry *entry;
     int ret = 0;
 
     entry = ftrace_lookup_ip(hash, rec->ip);
     if (clear_filter) {
         /* Do nothing if it doesn't exist */
         if (!entry)
             return 0;
 
         free_hash_entry(hash, entry);
     } else {
         /* Do nothing if it exists */
         if (entry)
             return 0;
 
         ret = add_hash_entry(hash, rec->ip);
     }
     return ret;
 }
 
 static int
 add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
          int clear_filter)
 {
     long index = simple_strtoul(func_g->search, NULL, 0);
     struct ftrace_page *pg;
     struct dyn_ftrace *rec;
 
     /* The index starts at 1 */
     if (--index < 0)
         return 0;
 
     do_for_each_ftrace_rec(pg, rec) {
         if (pg->index <= index) {
             index -= pg->index;
             /* this is a double loop, break goes to the next page */
             break;
         }
         rec = &pg->records[index];
         enter_record(hash, rec, clear_filter);
         return 1;
     } while_for_each_ftrace_rec();
     return 0;
 }
 
 #ifdef FTRACE_MCOUNT_MAX_OFFSET
 static int lookup_ip(unsigned long ip, char **modname, char *str)
 {
     unsigned long offset;
 
     kallsyms_lookup(ip, NULL, &offset, modname, str);
     if (offset > FTRACE_MCOUNT_MAX_OFFSET)
         return -1;
     return 0;
 }
 #else
 static int lookup_ip(unsigned long ip, char **modname, char *str)
 {
     kallsyms_lookup(ip, NULL, NULL, modname, str);
     return 0;
 }
 #endif
 
 static int
 ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
         struct ftrace_glob *mod_g, int exclude_mod)
 {
     char str[KSYM_SYMBOL_LEN];
     char *modname;
 
     if (lookup_ip(rec->ip, &modname, str)) {
         /* This should only happen when a rec is disabled */
         WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
                  !(rec->flags & FTRACE_FL_DISABLED));
         return 0;
     }
 
     if (mod_g) {
         int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
 
         /* blank module name to match all modules */
         if (!mod_g->len) {
             /* blank module globbing: modname xor exclude_mod */
             if (!exclude_mod != !modname)
                 goto func_match;
             return 0;
         }
 
         /*
          * exclude_mod is set to trace everything but the given
          * module. If it is set and the module matches, then
          * return 0. If it is not set, and the module doesn't match
          * also return 0. Otherwise, check the function to see if
          * that matches.
          */
         if (!mod_matches == !exclude_mod)
             return 0;
 func_match:
         /* blank search means to match all funcs in the mod */
         if (!func_g->len)
             return 1;
     }
 
     return ftrace_match(str, func_g);
 }
 
 static int
 match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
 {
     struct ftrace_page *pg;
     struct dyn_ftrace *rec;
     struct ftrace_glob func_g = { .type = MATCH_FULL };
     struct ftrace_glob mod_g = { .type = MATCH_FULL };
     struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
     int exclude_mod = 0;
     int found = 0;
     int ret;
     int clear_filter = 0;
 
     if (func) {
         func_g.type = filter_parse_regex(func, len, &func_g.search,
                          &clear_filter);
         func_g.len = strlen(func_g.search);
     }
 
     if (mod) {
         mod_g.type = filter_parse_regex(mod, strlen(mod),
                 &mod_g.search, &exclude_mod);
         mod_g.len = strlen(mod_g.search);
     }
 
     mutex_lock(&ftrace_lock);
 
     if (unlikely(ftrace_disabled))
         goto out_unlock;
 
     if (func_g.type == MATCH_INDEX) {
         found = add_rec_by_index(hash, &func_g, clear_filter);
         goto out_unlock;
     }
 
     do_for_each_ftrace_rec(pg, rec) {
 
         if (rec->flags & FTRACE_FL_DISABLED)
             continue;
 
         if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
             ret = enter_record(hash, rec, clear_filter);
             if (ret < 0) {
                 found = ret;
                 goto out_unlock;
             }
             found = 1;
         }
     } while_for_each_ftrace_rec();
  out_unlock:
     mutex_unlock(&ftrace_lock);
 
     return found;
 }
 
 static int
 ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
 {
     return match_records(hash, buff, len, NULL);
 }
 
 static void ftrace_ops_update_code(struct ftrace_ops *ops,
                    struct ftrace_ops_hash *old_hash)
 {
     struct ftrace_ops *op;
 
     if (!ftrace_enabled)
         return;
 
     if (ops->flags & FTRACE_OPS_FL_ENABLED) {
         ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
         return;
     }
 
     /*
      * If this is the shared global_ops filter, then we need to
      * check if there is another ops that shares it, is enabled.
      * If so, we still need to run the modify code.
      */
     if (ops->func_hash != &global_ops.local_hash)
         return;
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
         if (op->func_hash == &global_ops.local_hash &&
             op->flags & FTRACE_OPS_FL_ENABLED) {
             ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
             /* Only need to do this once */
             return;
         }
     } while_for_each_ftrace_op(op);
 }
 
 static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
                        struct ftrace_hash **orig_hash,
                        struct ftrace_hash *hash,
                        int enable)
 {
     struct ftrace_ops_hash old_hash_ops;
     struct ftrace_hash *old_hash;
     int ret;
 
     old_hash = *orig_hash;
     old_hash_ops.filter_hash = ops->func_hash->filter_hash;
     old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
     ret = ftrace_hash_move(ops, enable, orig_hash, hash);
     if (!ret) {
         ftrace_ops_update_code(ops, &old_hash_ops);
         free_ftrace_hash_rcu(old_hash);
     }
     return ret;
 }
 
 static bool module_exists(const char *module)
 {
     /* All modules have the symbol __this_module */
     static const char this_mod[] = "__this_module";
     char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
     unsigned long val;
     int n;
 
     n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
 
     if (n > sizeof(modname) - 1)
         return false;
 
     val = module_kallsyms_lookup_name(modname);
     return val != 0;
 }
 
 static int cache_mod(struct trace_array *tr,
              const char *func, char *module, int enable)
 {
     struct ftrace_mod_load *ftrace_mod, *n;
     struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
     int ret;
 
     mutex_lock(&ftrace_lock);
 
     /* We do not cache inverse filters */
     if (func[0] == '!') {
         func++;
         ret = -EINVAL;
 
         /* Look to remove this hash */
         list_for_each_entry_safe(ftrace_mod, n, head, list) {
             if (strcmp(ftrace_mod->module, module) != 0)
                 continue;
 
             /* no func matches all */
             if (strcmp(func, "*") == 0 ||
                 (ftrace_mod->func &&
                  strcmp(ftrace_mod->func, func) == 0)) {
                 ret = 0;
                 free_ftrace_mod(ftrace_mod);
                 continue;
             }
         }
         goto out;
     }
 
     ret = -EINVAL;
     /* We only care about modules that have not been loaded yet */
     if (module_exists(module))
         goto out;
 
     /* Save this string off, and execute it when the module is loaded */
     ret = ftrace_add_mod(tr, func, module, enable);
  out:
     mutex_unlock(&ftrace_lock);
 
     return ret;
 }
 
 static int
 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
          int reset, int enable);
 
 #ifdef CONFIG_MODULES
 static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
                  char *mod, bool enable)
 {
     struct ftrace_mod_load *ftrace_mod, *n;
     struct ftrace_hash **orig_hash, *new_hash;
     LIST_HEAD(process_mods);
     char *func;
 
     mutex_lock(&ops->func_hash->regex_lock);
 
     if (enable)
         orig_hash = &ops->func_hash->filter_hash;
     else
         orig_hash = &ops->func_hash->notrace_hash;
 
     new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
                           *orig_hash);
     if (!new_hash)
         goto out; /* warn? */
 
     mutex_lock(&ftrace_lock);
 
     list_for_each_entry_safe(ftrace_mod, n, head, list) {
 
         if (strcmp(ftrace_mod->module, mod) != 0)
             continue;
 
         if (ftrace_mod->func)
             func = kstrdup(ftrace_mod->func, GFP_KERNEL);
         else
             func = kstrdup("*", GFP_KERNEL);
 
         if (!func) /* warn? */
             continue;
 
         list_move(&ftrace_mod->list, &process_mods);
 
         /* Use the newly allocated func, as it may be "*" */
         kfree(ftrace_mod->func);
         ftrace_mod->func = func;
     }
 
     mutex_unlock(&ftrace_lock);
 
     list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
 
         func = ftrace_mod->func;
 
         /* Grabs ftrace_lock, which is why we have this extra step */
         match_records(new_hash, func, strlen(func), mod);
         free_ftrace_mod(ftrace_mod);
     }
 
     if (enable && list_empty(head))
         new_hash->flags &= ~FTRACE_HASH_FL_MOD;
 
     mutex_lock(&ftrace_lock);
 
     ftrace_hash_move_and_update_ops(ops, orig_hash,
                           new_hash, enable);
     mutex_unlock(&ftrace_lock);
 
  out:
     mutex_unlock(&ops->func_hash->regex_lock);
 
     free_ftrace_hash(new_hash);
 }
 
 static void process_cached_mods(const char *mod_name)
 {
     struct trace_array *tr;
     char *mod;
 
     mod = kstrdup(mod_name, GFP_KERNEL);
     if (!mod)
         return;
 
     mutex_lock(&trace_types_lock);
     list_for_each_entry(tr, &ftrace_trace_arrays, list) {
         if (!list_empty(&tr->mod_trace))
             process_mod_list(&tr->mod_trace, tr->ops, mod, true);
         if (!list_empty(&tr->mod_notrace))
             process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
     }
     mutex_unlock(&trace_types_lock);
 
     kfree(mod);
 }
 #endif
 
 /*
  * We register the module command as a template to show others how
  * to register the a command as well.
  */
 
 static int
 ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
             char *func_orig, char *cmd, char *module, int enable)
 {
     char *func;
     int ret;
 
     /* match_records() modifies func, and we need the original */
     func = kstrdup(func_orig, GFP_KERNEL);
     if (!func)
         return -ENOMEM;
 
     /*
      * cmd == 'mod' because we only registered this func
      * for the 'mod' ftrace_func_command.
      * But if you register one func with multiple commands,
      * you can tell which command was used by the cmd
      * parameter.
      */
     ret = match_records(hash, func, strlen(func), module);
     kfree(func);
 
     if (!ret)
         return cache_mod(tr, func_orig, module, enable);
     if (ret < 0)
         return ret;
     return 0;
 }
 
 static struct ftrace_func_command ftrace_mod_cmd = {
     .name           = "mod",
     .func           = ftrace_mod_callback,
 };
 
 static int __init ftrace_mod_cmd_init(void)
 {
     return register_ftrace_command(&ftrace_mod_cmd);
 }
 core_initcall(ftrace_mod_cmd_init);
 
 static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
                       struct ftrace_ops *op, struct ftrace_regs *fregs)
 {
     struct ftrace_probe_ops *probe_ops;
     struct ftrace_func_probe *probe;
 
     probe = container_of(op, struct ftrace_func_probe, ops);
     probe_ops = probe->probe_ops;
 
     /*
      * Disable preemption for these calls to prevent a RCU grace
      * period. This syncs the hash iteration and freeing of items
      * on the hash. rcu_read_lock is too dangerous here.
      */
     preempt_disable_notrace();
     probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
     preempt_enable_notrace();
 }
 
 struct ftrace_func_map {
     struct ftrace_func_entry    entry;
     void                *data;
 };
 
 struct ftrace_func_mapper {
     struct ftrace_hash      hash;
 };
 
 /**
  * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
  *
  * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
  */
 struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
 {
     struct ftrace_hash *hash;
 
     /*
      * The mapper is simply a ftrace_hash, but since the entries
      * in the hash are not ftrace_func_entry type, we define it
      * as a separate structure.
      */
     hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
     return (struct ftrace_func_mapper *)hash;
 }
 
 /**
  * ftrace_func_mapper_find_ip - Find some data mapped to an ip
  * @mapper: The mapper that has the ip maps
  * @ip: the instruction pointer to find the data for
  *
  * Returns the data mapped to @ip if found otherwise NULL. The return
  * is actually the address of the mapper data pointer. The address is
  * returned for use cases where the data is no bigger than a long, and
  * the user can use the data pointer as its data instead of having to
  * allocate more memory for the reference.
  */
 void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
                   unsigned long ip)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_func_map *map;
 
     entry = ftrace_lookup_ip(&mapper->hash, ip);
     if (!entry)
         return NULL;
 
     map = (struct ftrace_func_map *)entry;
     return &map->data;
 }
 
 /**
  * ftrace_func_mapper_add_ip - Map some data to an ip
  * @mapper: The mapper that has the ip maps
  * @ip: The instruction pointer address to map @data to
  * @data: The data to map to @ip
  *
  * Returns 0 on success otherwise an error.
  */
 int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
                   unsigned long ip, void *data)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_func_map *map;
 
     entry = ftrace_lookup_ip(&mapper->hash, ip);
     if (entry)
         return -EBUSY;
 
     map = kmalloc(sizeof(*map), GFP_KERNEL);
     if (!map)
         return -ENOMEM;
 
     map->entry.ip = ip;
     map->data = data;
 
     __add_hash_entry(&mapper->hash, &map->entry);
 
     return 0;
 }
 
 /**
  * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
  * @mapper: The mapper that has the ip maps
  * @ip: The instruction pointer address to remove the data from
  *
  * Returns the data if it is found, otherwise NULL.
  * Note, if the data pointer is used as the data itself, (see
  * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
  * if the data pointer was set to zero.
  */
 void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
                    unsigned long ip)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_func_map *map;
     void *data;
 
     entry = ftrace_lookup_ip(&mapper->hash, ip);
     if (!entry)
         return NULL;
 
     map = (struct ftrace_func_map *)entry;
     data = map->data;
 
     remove_hash_entry(&mapper->hash, entry);
     kfree(entry);
 
     return data;
 }
 
 /**
  * free_ftrace_func_mapper - free a mapping of ips and data
  * @mapper: The mapper that has the ip maps
  * @free_func: A function to be called on each data item.
  *
  * This is used to free the function mapper. The @free_func is optional
  * and can be used if the data needs to be freed as well.
  */
 void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
                  ftrace_mapper_func free_func)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_func_map *map;
     struct hlist_head *hhd;
     int size, i;
 
     if (!mapper)
         return;
 
     if (free_func && mapper->hash.count) {
         size = 1 << mapper->hash.size_bits;
         for (i = 0; i < size; i++) {
             hhd = &mapper->hash.buckets[i];
             hlist_for_each_entry(entry, hhd, hlist) {
                 map = (struct ftrace_func_map *)entry;
                 free_func(map);
             }
         }
     }
     free_ftrace_hash(&mapper->hash);
 }
 
 static void release_probe(struct ftrace_func_probe *probe)
 {
     struct ftrace_probe_ops *probe_ops;
 
     mutex_lock(&ftrace_lock);
 
     WARN_ON(probe->ref <= 0);
 
     /* Subtract the ref that was used to protect this instance */
     probe->ref--;
 
     if (!probe->ref) {
         probe_ops = probe->probe_ops;
         /*
          * Sending zero as ip tells probe_ops to free
          * the probe->data itself
          */
         if (probe_ops->free)
             probe_ops->free(probe_ops, probe->tr, 0, probe->data);
         list_del(&probe->list);
         kfree(probe);
     }
     mutex_unlock(&ftrace_lock);
 }
 
 static void acquire_probe_locked(struct ftrace_func_probe *probe)
 {
     /*
      * Add one ref to keep it from being freed when releasing the
      * ftrace_lock mutex.
      */
     probe->ref++;
 }
 
 int
 register_ftrace_function_probe(char *glob, struct trace_array *tr,
                    struct ftrace_probe_ops *probe_ops,
                    void *data)
 {
     struct ftrace_func_probe *probe = NULL, *iter;
     struct ftrace_func_entry *entry;
     struct ftrace_hash **orig_hash;
     struct ftrace_hash *old_hash;
     struct ftrace_hash *hash;
     int count = 0;
     int size;
     int ret;
     int i;
 
     if (WARN_ON(!tr))
         return -EINVAL;
 
     /* We do not support '!' for function probes */
     if (WARN_ON(glob[0] == '!'))
         return -EINVAL;
 
 
     mutex_lock(&ftrace_lock);
     /* Check if the probe_ops is already registered */
     list_for_each_entry(iter, &tr->func_probes, list) {
         if (iter->probe_ops == probe_ops) {
             probe = iter;
             break;
         }
     }
     if (!probe) {
         probe = kzalloc(sizeof(*probe), GFP_KERNEL);
         if (!probe) {
             mutex_unlock(&ftrace_lock);
             return -ENOMEM;
         }
         probe->probe_ops = probe_ops;
         probe->ops.func = function_trace_probe_call;
         probe->tr = tr;
         ftrace_ops_init(&probe->ops);
         list_add(&probe->list, &tr->func_probes);
     }
 
     acquire_probe_locked(probe);
 
     mutex_unlock(&ftrace_lock);
 
     /*
      * Note, there's a small window here that the func_hash->filter_hash
      * may be NULL or empty. Need to be careful when reading the loop.
      */
     mutex_lock(&probe->ops.func_hash->regex_lock);
 
     orig_hash = &probe->ops.func_hash->filter_hash;
     old_hash = *orig_hash;
     hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
 
     if (!hash) {
         ret = -ENOMEM;
         goto out;
     }
 
     ret = ftrace_match_records(hash, glob, strlen(glob));
 
     /* Nothing found? */
     if (!ret)
         ret = -EINVAL;
 
     if (ret < 0)
         goto out;
 
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             if (ftrace_lookup_ip(old_hash, entry->ip))
                 continue;
             /*
              * The caller might want to do something special
              * for each function we find. We call the callback
              * to give the caller an opportunity to do so.
              */
             if (probe_ops->init) {
                 ret = probe_ops->init(probe_ops, tr,
                               entry->ip, data,
                               &probe->data);
                 if (ret < 0) {
                     if (probe_ops->free && count)
                         probe_ops->free(probe_ops, tr,
                                 0, probe->data);
                     probe->data = NULL;
                     goto out;
                 }
             }
             count++;
         }
     }
 
     mutex_lock(&ftrace_lock);
 
     if (!count) {
         /* Nothing was added? */
         ret = -EINVAL;
         goto out_unlock;
     }
 
     ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
                           hash, 1);
     if (ret < 0)
         goto err_unlock;
 
     /* One ref for each new function traced */
     probe->ref += count;
 
     if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
         ret = ftrace_startup(&probe->ops, 0);
 
  out_unlock:
     mutex_unlock(&ftrace_lock);
 
     if (!ret)
         ret = count;
  out:
     mutex_unlock(&probe->ops.func_hash->regex_lock);
     free_ftrace_hash(hash);
 
     release_probe(probe);
 
     return ret;
 
  err_unlock:
     if (!probe_ops->free || !count)
         goto out_unlock;
 
     /* Failed to do the move, need to call the free functions */
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             if (ftrace_lookup_ip(old_hash, entry->ip))
                 continue;
             probe_ops->free(probe_ops, tr, entry->ip, probe->data);
         }
     }
     goto out_unlock;
 }
 
 int
 unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
                       struct ftrace_probe_ops *probe_ops)
 {
     struct ftrace_func_probe *probe = NULL, *iter;
     struct ftrace_ops_hash old_hash_ops;
     struct ftrace_func_entry *entry;
     struct ftrace_glob func_g;
     struct ftrace_hash **orig_hash;
     struct ftrace_hash *old_hash;
     struct ftrace_hash *hash = NULL;
     struct hlist_node *tmp;
     struct hlist_head hhd;
     char str[KSYM_SYMBOL_LEN];
     int count = 0;
     int i, ret = -ENODEV;
     int size;
 
     if (!glob || !strlen(glob) || !strcmp(glob, "*"))
         func_g.search = NULL;
     else {
         int not;
 
         func_g.type = filter_parse_regex(glob, strlen(glob),
                          &func_g.search, &not);
         func_g.len = strlen(func_g.search);
 
         /* we do not support '!' for function probes */
         if (WARN_ON(not))
             return -EINVAL;
     }
 
     mutex_lock(&ftrace_lock);
     /* Check if the probe_ops is already registered */
     list_for_each_entry(iter, &tr->func_probes, list) {
         if (iter->probe_ops == probe_ops) {
             probe = iter;
             break;
         }
     }
     if (!probe)
         goto err_unlock_ftrace;
 
     ret = -EINVAL;
     if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
         goto err_unlock_ftrace;
 
     acquire_probe_locked(probe);
 
     mutex_unlock(&ftrace_lock);
 
     mutex_lock(&probe->ops.func_hash->regex_lock);
 
     orig_hash = &probe->ops.func_hash->filter_hash;
     old_hash = *orig_hash;
 
     if (ftrace_hash_empty(old_hash))
         goto out_unlock;
 
     old_hash_ops.filter_hash = old_hash;
     /* Probes only have filters */
     old_hash_ops.notrace_hash = NULL;
 
     ret = -ENOMEM;
     hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
     if (!hash)
         goto out_unlock;
 
     INIT_HLIST_HEAD(&hhd);
 
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
 
             if (func_g.search) {
                 kallsyms_lookup(entry->ip, NULL, NULL,
                         NULL, str);
                 if (!ftrace_match(str, &func_g))
                     continue;
             }
             count++;
             remove_hash_entry(hash, entry);
             hlist_add_head(&entry->hlist, &hhd);
         }
     }
 
     /* Nothing found? */
     if (!count) {
         ret = -EINVAL;
         goto out_unlock;
     }
 
     mutex_lock(&ftrace_lock);
 
     WARN_ON(probe->ref < count);
 
     probe->ref -= count;
 
     if (ftrace_hash_empty(hash))
         ftrace_shutdown(&probe->ops, 0);
 
     ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
                           hash, 1);
 
     /* still need to update the function call sites */
     if (ftrace_enabled && !ftrace_hash_empty(hash))
         ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
                        &old_hash_ops);
     synchronize_rcu();
 
     hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
         hlist_del(&entry->hlist);
         if (probe_ops->free)
             probe_ops->free(probe_ops, tr, entry->ip, probe->data);
         kfree(entry);
     }
     mutex_unlock(&ftrace_lock);
 
  out_unlock:
     mutex_unlock(&probe->ops.func_hash->regex_lock);
     free_ftrace_hash(hash);
 
     release_probe(probe);
 
     return ret;
 
  err_unlock_ftrace:
     mutex_unlock(&ftrace_lock);
     return ret;
 }
 
 void clear_ftrace_function_probes(struct trace_array *tr)
 {
     struct ftrace_func_probe *probe, *n;
 
     list_for_each_entry_safe(probe, n, &tr->func_probes, list)
         unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
 }
 
 static LIST_HEAD(ftrace_commands);
 static DEFINE_MUTEX(ftrace_cmd_mutex);
 
 /*
  * Currently we only register ftrace commands from __init, so mark this
  * __init too.
  */
 __init int register_ftrace_command(struct ftrace_func_command *cmd)
 {
     struct ftrace_func_command *p;
     int ret = 0;
 
     mutex_lock(&ftrace_cmd_mutex);
     list_for_each_entry(p, &ftrace_commands, list) {
         if (strcmp(cmd->name, p->name) == 0) {
             ret = -EBUSY;
             goto out_unlock;
         }
     }
     list_add(&cmd->list, &ftrace_commands);
  out_unlock:
     mutex_unlock(&ftrace_cmd_mutex);
 
     return ret;
 }
 
 /*
  * Currently we only unregister ftrace commands from __init, so mark
  * this __init too.
  */
 __init int unregister_ftrace_command(struct ftrace_func_command *cmd)
 {
     struct ftrace_func_command *p, *n;
     int ret = -ENODEV;
 
     mutex_lock(&ftrace_cmd_mutex);
     list_for_each_entry_safe(p, n, &ftrace_commands, list) {
         if (strcmp(cmd->name, p->name) == 0) {
             ret = 0;
             list_del_init(&p->list);
             goto out_unlock;
         }
     }
  out_unlock:
     mutex_unlock(&ftrace_cmd_mutex);
 
     return ret;
 }
 
 static int ftrace_process_regex(struct ftrace_iterator *iter,
                 char *buff, int len, int enable)
 {
     struct ftrace_hash *hash = iter->hash;
     struct trace_array *tr = iter->ops->private;
     char *func, *command, *next = buff;
     struct ftrace_func_command *p;
     int ret = -EINVAL;
 
     func = strsep(&next, ":");
 
     if (!next) {
         ret = ftrace_match_records(hash, func, len);
         if (!ret)
             ret = -EINVAL;
         if (ret < 0)
             return ret;
         return 0;
     }
 
     /* command found */
 
     command = strsep(&next, ":");
 
     mutex_lock(&ftrace_cmd_mutex);
     list_for_each_entry(p, &ftrace_commands, list) {
         if (strcmp(p->name, command) == 0) {
             ret = p->func(tr, hash, func, command, next, enable);
             goto out_unlock;
         }
     }
  out_unlock:
     mutex_unlock(&ftrace_cmd_mutex);
 
     return ret;
 }
 
 static ssize_t
 ftrace_regex_write(struct file *file, const char __user *ubuf,
            size_t cnt, loff_t *ppos, int enable)
 {
     struct ftrace_iterator *iter;
     struct trace_parser *parser;
     ssize_t ret, read;
 
     if (!cnt)
         return 0;
 
     if (file->f_mode & FMODE_READ) {
         struct seq_file *m = file->private_data;
         iter = m->private;
     } else
         iter = file->private_data;
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     /* iter->hash is a local copy, so we don't need regex_lock */
 
     parser = &iter->parser;
     read = trace_get_user(parser, ubuf, cnt, ppos);
 
     if (read >= 0 && trace_parser_loaded(parser) &&
         !trace_parser_cont(parser)) {
         ret = ftrace_process_regex(iter, parser->buffer,
                        parser->idx, enable);
         trace_parser_clear(parser);
         if (ret < 0)
             goto out;
     }
 
     ret = read;
  out:
     return ret;
 }
 
 ssize_t
 ftrace_filter_write(struct file *file, const char __user *ubuf,
             size_t cnt, loff_t *ppos)
 {
     return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
 }
 
 ssize_t
 ftrace_notrace_write(struct file *file, const char __user *ubuf,
              size_t cnt, loff_t *ppos)
 {
     return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
 }
 
 static int
 __ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
 {
     struct ftrace_func_entry *entry;
 
     ip = ftrace_location(ip);
     if (!ip)
         return -EINVAL;
 
     if (remove) {
         entry = ftrace_lookup_ip(hash, ip);
         if (!entry)
             return -ENOENT;
         free_hash_entry(hash, entry);
         return 0;
     }
 
     return add_hash_entry(hash, ip);
 }
 
 static int
 ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
           unsigned int cnt, int remove)
 {
     unsigned int i;
     int err;
 
     for (i = 0; i < cnt; i++) {
         err = __ftrace_match_addr(hash, ips[i], remove);
         if (err) {
             /*
              * This expects the @hash is a temporary hash and if this
              * fails the caller must free the @hash.
              */
             return err;
         }
     }
     return 0;
 }
 
 static int
 ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
         unsigned long *ips, unsigned int cnt,
         int remove, int reset, int enable)
 {
     struct ftrace_hash **orig_hash;
     struct ftrace_hash *hash;
     int ret;
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     mutex_lock(&ops->func_hash->regex_lock);
 
     if (enable)
         orig_hash = &ops->func_hash->filter_hash;
     else
         orig_hash = &ops->func_hash->notrace_hash;
 
     if (reset)
         hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
     else
         hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
 
     if (!hash) {
         ret = -ENOMEM;
         goto out_regex_unlock;
     }
 
     if (buf && !ftrace_match_records(hash, buf, len)) {
         ret = -EINVAL;
         goto out_regex_unlock;
     }
     if (ips) {
         ret = ftrace_match_addr(hash, ips, cnt, remove);
         if (ret < 0)
             goto out_regex_unlock;
     }
 
     mutex_lock(&ftrace_lock);
     ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
     mutex_unlock(&ftrace_lock);
 
  out_regex_unlock:
     mutex_unlock(&ops->func_hash->regex_lock);
 
     free_ftrace_hash(hash);
     return ret;
 }
 
 static int
 ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
         int remove, int reset, int enable)
 {
     return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 
 struct ftrace_direct_func {
     struct list_head    next;
     unsigned long       addr;
     int         count;
 };
 
 static LIST_HEAD(ftrace_direct_funcs);
 
 /**
  * ftrace_find_direct_func - test an address if it is a registered direct caller
  * @addr: The address of a registered direct caller
  *
  * This searches to see if a ftrace direct caller has been registered
  * at a specific address, and if so, it returns a descriptor for it.
  *
  * This can be used by architecture code to see if an address is
  * a direct caller (trampoline) attached to a fentry/mcount location.
  * This is useful for the function_graph tracer, as it may need to
  * do adjustments if it traced a location that also has a direct
  * trampoline attached to it.
  */
 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
 {
     struct ftrace_direct_func *entry;
     bool found = false;
 
     /* May be called by fgraph trampoline (protected by rcu tasks) */
     list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
         if (entry->addr == addr) {
             found = true;
             break;
         }
     }
     if (found)
         return entry;
 
     return NULL;
 }
 
 static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
 {
     struct ftrace_direct_func *direct;
 
     direct = kmalloc(sizeof(*direct), GFP_KERNEL);
     if (!direct)
         return NULL;
     direct->addr = addr;
     direct->count = 0;
     list_add_rcu(&direct->next, &ftrace_direct_funcs);
     ftrace_direct_func_count++;
     return direct;
 }
 
 static int register_ftrace_function_nolock(struct ftrace_ops *ops);
 
 /**
  * register_ftrace_direct - Call a custom trampoline directly
  * @ip: The address of the nop at the beginning of a function
  * @addr: The address of the trampoline to call at @ip
  *
  * This is used to connect a direct call from the nop location (@ip)
  * at the start of ftrace traced functions. The location that it calls
  * (@addr) must be able to handle a direct call, and save the parameters
  * of the function being traced, and restore them (or inject new ones
  * if needed), before returning.
  *
  * Returns:
  *  0 on success
  *  -EBUSY - Another direct function is already attached (there can be only one)
  *  -ENODEV - @ip does not point to a ftrace nop location (or not supported)
  *  -ENOMEM - There was an allocation failure.
  */
 int register_ftrace_direct(unsigned long ip, unsigned long addr)
 {
     struct ftrace_direct_func *direct;
     struct ftrace_func_entry *entry;
     struct ftrace_hash *free_hash = NULL;
     struct dyn_ftrace *rec;
     int ret = -ENODEV;
 
     mutex_lock(&direct_mutex);
 
     ip = ftrace_location(ip);
     if (!ip)
         goto out_unlock;
 
     /* See if there's a direct function at @ip already */
     ret = -EBUSY;
     if (ftrace_find_rec_direct(ip))
         goto out_unlock;
 
     ret = -ENODEV;
     rec = lookup_rec(ip, ip);
     if (!rec)
         goto out_unlock;
 
     /*
      * Check if the rec says it has a direct call but we didn't
      * find one earlier?
      */
     if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
         goto out_unlock;
 
     /* Make sure the ip points to the exact record */
     if (ip != rec->ip) {
         ip = rec->ip;
         /* Need to check this ip for a direct. */
         if (ftrace_find_rec_direct(ip))
             goto out_unlock;
     }
 
     ret = -ENOMEM;
     direct = ftrace_find_direct_func(addr);
     if (!direct) {
         direct = ftrace_alloc_direct_func(addr);
         if (!direct)
             goto out_unlock;
     }
 
     entry = ftrace_add_rec_direct(ip, addr, &free_hash);
     if (!entry)
         goto out_unlock;
 
     ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
 
     if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
         ret = register_ftrace_function_nolock(&direct_ops);
         if (ret)
             ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
     }
 
     if (ret) {
         remove_hash_entry(direct_functions, entry);
         kfree(entry);
         if (!direct->count) {
             list_del_rcu(&direct->next);
             synchronize_rcu_tasks();
             kfree(direct);
             if (free_hash)
                 free_ftrace_hash(free_hash);
             free_hash = NULL;
             ftrace_direct_func_count--;
         }
     } else {
         direct->count++;
     }
  out_unlock:
     mutex_unlock(&direct_mutex);
 
     if (free_hash) {
         synchronize_rcu_tasks();
         free_ftrace_hash(free_hash);
     }
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(register_ftrace_direct);
 
 static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
                            struct dyn_ftrace **recp)
 {
     struct ftrace_func_entry *entry;
     struct dyn_ftrace *rec;
 
     rec = lookup_rec(*ip, *ip);
     if (!rec)
         return NULL;
 
     entry = __ftrace_lookup_ip(direct_functions, rec->ip);
     if (!entry) {
         WARN_ON(rec->flags & FTRACE_FL_DIRECT);
         return NULL;
     }
 
     WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
 
     /* Passed in ip just needs to be on the call site */
     *ip = rec->ip;
 
     if (recp)
         *recp = rec;
 
     return entry;
 }
 
 int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
 {
     struct ftrace_direct_func *direct;
     struct ftrace_func_entry *entry;
     struct ftrace_hash *hash;
     int ret = -ENODEV;
 
     mutex_lock(&direct_mutex);
 
     ip = ftrace_location(ip);
     if (!ip)
         goto out_unlock;
 
     entry = find_direct_entry(&ip, NULL);
     if (!entry)
         goto out_unlock;
 
     hash = direct_ops.func_hash->filter_hash;
     if (hash->count == 1)
         unregister_ftrace_function(&direct_ops);
 
     ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
 
     WARN_ON(ret);
 
     remove_hash_entry(direct_functions, entry);
 
     direct = ftrace_find_direct_func(addr);
     if (!WARN_ON(!direct)) {
         /* This is the good path (see the ! before WARN) */
         direct->count--;
         WARN_ON(direct->count < 0);
         if (!direct->count) {
             list_del_rcu(&direct->next);
             synchronize_rcu_tasks();
             kfree(direct);
             kfree(entry);
             ftrace_direct_func_count--;
         }
     }
  out_unlock:
     mutex_unlock(&direct_mutex);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
 
 static struct ftrace_ops stub_ops = {
     .func       = ftrace_stub,
 };
 
 /**
  * ftrace_modify_direct_caller - modify ftrace nop directly
  * @entry: The ftrace hash entry of the direct helper for @rec
  * @rec: The record representing the function site to patch
  * @old_addr: The location that the site at @rec->ip currently calls
  * @new_addr: The location that the site at @rec->ip should call
  *
  * An architecture may overwrite this function to optimize the
  * changing of the direct callback on an ftrace nop location.
  * This is called with the ftrace_lock mutex held, and no other
  * ftrace callbacks are on the associated record (@rec). Thus,
  * it is safe to modify the ftrace record, where it should be
  * currently calling @old_addr directly, to call @new_addr.
  *
  * Safety checks should be made to make sure that the code at
  * @rec->ip is currently calling @old_addr. And this must
  * also update entry->direct to @new_addr.
  */
 int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
                        struct dyn_ftrace *rec,
                        unsigned long old_addr,
                        unsigned long new_addr)
 {
     unsigned long ip = rec->ip;
     int ret;
 
     /*
      * The ftrace_lock was used to determine if the record
      * had more than one registered user to it. If it did,
      * we needed to prevent that from changing to do the quick
      * switch. But if it did not (only a direct caller was attached)
      * then this function is called. But this function can deal
      * with attached callers to the rec that we care about, and
      * since this function uses standard ftrace calls that take
      * the ftrace_lock mutex, we need to release it.
      */
     mutex_unlock(&ftrace_lock);
 
     /*
      * By setting a stub function at the same address, we force
      * the code to call the iterator and the direct_ops helper.
      * This means that @ip does not call the direct call, and
      * we can simply modify it.
      */
     ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
     if (ret)
         goto out_lock;
 
     ret = register_ftrace_function(&stub_ops);
     if (ret) {
         ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
         goto out_lock;
     }
 
     entry->direct = new_addr;
 
     /*
      * By removing the stub, we put back the direct call, calling
      * the @new_addr.
      */
     unregister_ftrace_function(&stub_ops);
     ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
 
  out_lock:
     mutex_lock(&ftrace_lock);
 
     return ret;
 }
 
 /**
  * modify_ftrace_direct - Modify an existing direct call to call something else
  * @ip: The instruction pointer to modify
  * @old_addr: The address that the current @ip calls directly
  * @new_addr: The address that the @ip should call
  *
  * This modifies a ftrace direct caller at an instruction pointer without
  * having to disable it first. The direct call will switch over to the
  * @new_addr without missing anything.
  *
  * Returns: zero on success. Non zero on error, which includes:
  *  -ENODEV : the @ip given has no direct caller attached
  *  -EINVAL : the @old_addr does not match the current direct caller
  */
 int modify_ftrace_direct(unsigned long ip,
              unsigned long old_addr, unsigned long new_addr)
 {
     struct ftrace_direct_func *direct, *new_direct = NULL;
     struct ftrace_func_entry *entry;
     struct dyn_ftrace *rec;
     int ret = -ENODEV;
 
     mutex_lock(&direct_mutex);
 
     mutex_lock(&ftrace_lock);
 
     ip = ftrace_location(ip);
     if (!ip)
         goto out_unlock;
 
     entry = find_direct_entry(&ip, &rec);
     if (!entry)
         goto out_unlock;
 
     ret = -EINVAL;
     if (entry->direct != old_addr)
         goto out_unlock;
 
     direct = ftrace_find_direct_func(old_addr);
     if (WARN_ON(!direct))
         goto out_unlock;
     if (direct->count > 1) {
         ret = -ENOMEM;
         new_direct = ftrace_alloc_direct_func(new_addr);
         if (!new_direct)
             goto out_unlock;
         direct->count--;
         new_direct->count++;
     } else {
         direct->addr = new_addr;
     }
 
     /*
      * If there's no other ftrace callback on the rec->ip location,
      * then it can be changed directly by the architecture.
      * If there is another caller, then we just need to change the
      * direct caller helper to point to @new_addr.
      */
     if (ftrace_rec_count(rec) == 1) {
         ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
     } else {
         entry->direct = new_addr;
         ret = 0;
     }
 
     if (unlikely(ret && new_direct)) {
         direct->count++;
         list_del_rcu(&new_direct->next);
         synchronize_rcu_tasks();
         kfree(new_direct);
         ftrace_direct_func_count--;
     }
 
  out_unlock:
     mutex_unlock(&ftrace_lock);
     mutex_unlock(&direct_mutex);
     return ret;
 }
 EXPORT_SYMBOL_GPL(modify_ftrace_direct);
 
 #define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
 
 static int check_direct_multi(struct ftrace_ops *ops)
 {
     if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
         return -EINVAL;
     if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
         return -EINVAL;
     return 0;
 }
 
 static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
 {
     struct ftrace_func_entry *entry, *del;
     int size, i;
 
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             del = __ftrace_lookup_ip(direct_functions, entry->ip);
             if (del && del->direct == addr) {
                 remove_hash_entry(direct_functions, del);
                 kfree(del);
             }
         }
     }
 }
 
 /**
  * register_ftrace_direct_multi - Call a custom trampoline directly
  * for multiple functions registered in @ops
  * @ops: The address of the struct ftrace_ops object
  * @addr: The address of the trampoline to call at @ops functions
  *
  * This is used to connect a direct calls to @addr from the nop locations
  * of the functions registered in @ops (with by ftrace_set_filter_ip
  * function).
  *
  * The location that it calls (@addr) must be able to handle a direct call,
  * and save the parameters of the function being traced, and restore them
  * (or inject new ones if needed), before returning.
  *
  * Returns:
  *  0 on success
  *  -EINVAL  - The @ops object was already registered with this call or
  *             when there are no functions in @ops object.
  *  -EBUSY   - Another direct function is already attached (there can be only one)
  *  -ENODEV  - @ip does not point to a ftrace nop location (or not supported)
  *  -ENOMEM  - There was an allocation failure.
  */
 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
     struct ftrace_hash *hash, *free_hash = NULL;
     struct ftrace_func_entry *entry, *new;
     int err = -EBUSY, size, i;
 
     if (ops->func || ops->trampoline)
         return -EINVAL;
     if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
         return -EINVAL;
     if (ops->flags & FTRACE_OPS_FL_ENABLED)
         return -EINVAL;
 
     hash = ops->func_hash->filter_hash;
     if (ftrace_hash_empty(hash))
         return -EINVAL;
 
     mutex_lock(&direct_mutex);
 
     /* Make sure requested entries are not already registered.. */
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             if (ftrace_find_rec_direct(entry->ip))
                 goto out_unlock;
         }
     }
 
     /* ... and insert them to direct_functions hash. */
     err = -ENOMEM;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
             if (!new)
                 goto out_remove;
             entry->direct = addr;
         }
     }
 
     ops->func = call_direct_funcs;
     ops->flags = MULTI_FLAGS;
     ops->trampoline = FTRACE_REGS_ADDR;
 
     err = register_ftrace_function_nolock(ops);
 
  out_remove:
     if (err)
         remove_direct_functions_hash(hash, addr);
 
  out_unlock:
     mutex_unlock(&direct_mutex);
 
     if (free_hash) {
         synchronize_rcu_tasks();
         free_ftrace_hash(free_hash);
     }
     return err;
 }
 EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
 
 /**
  * unregister_ftrace_direct_multi - Remove calls to custom trampoline
  * previously registered by register_ftrace_direct_multi for @ops object.
  * @ops: The address of the struct ftrace_ops object
  *
  * This is used to remove a direct calls to @addr from the nop locations
  * of the functions registered in @ops (with by ftrace_set_filter_ip
  * function).
  *
  * Returns:
  *  0 on success
  *  -EINVAL - The @ops object was not properly registered.
  */
 int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
     struct ftrace_hash *hash = ops->func_hash->filter_hash;
     int err;
 
     if (check_direct_multi(ops))
         return -EINVAL;
     if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
         return -EINVAL;
 
     mutex_lock(&direct_mutex);
     err = unregister_ftrace_function(ops);
     remove_direct_functions_hash(hash, addr);
     mutex_unlock(&direct_mutex);
 
     /* cleanup for possible another register call */
     ops->func = NULL;
     ops->trampoline = 0;
     return err;
 }
 EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
 
 static int
 __modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
     struct ftrace_hash *hash;
     struct ftrace_func_entry *entry, *iter;
     static struct ftrace_ops tmp_ops = {
         .func       = ftrace_stub,
         .flags      = FTRACE_OPS_FL_STUB,
     };
     int i, size;
     int err;
 
     lockdep_assert_held_once(&direct_mutex);
 
     /* Enable the tmp_ops to have the same functions as the direct ops */
     ftrace_ops_init(&tmp_ops);
     tmp_ops.func_hash = ops->func_hash;
 
     err = register_ftrace_function_nolock(&tmp_ops);
     if (err)
         return err;
 
     /*
      * Now the ftrace_ops_list_func() is called to do the direct callers.
      * We can safely change the direct functions attached to each entry.
      */
     mutex_lock(&ftrace_lock);
 
     hash = ops->func_hash->filter_hash;
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
             entry = __ftrace_lookup_ip(direct_functions, iter->ip);
             if (!entry)
                 continue;
             entry->direct = addr;
         }
     }
 
     mutex_unlock(&ftrace_lock);
 
     /* Removing the tmp_ops will add the updated direct callers to the functions */
     unregister_ftrace_function(&tmp_ops);
 
     return err;
 }
 
 /**
  * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
  * to call something else
  * @ops: The address of the struct ftrace_ops object
  * @addr: The address of the new trampoline to call at @ops functions
  *
  * This is used to unregister currently registered direct caller and
  * register new one @addr on functions registered in @ops object.
  *
  * Note there's window between ftrace_shutdown and ftrace_startup calls
  * where there will be no callbacks called.
  *
  * Caller should already have direct_mutex locked, so we don't lock
  * direct_mutex here.
  *
  * Returns: zero on success. Non zero on error, which includes:
  *  -EINVAL - The @ops object was not properly registered.
  */
 int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
 {
     if (check_direct_multi(ops))
         return -EINVAL;
     if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
         return -EINVAL;
 
     return __modify_ftrace_direct_multi(ops, addr);
 }
 EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
 
 /**
  * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
  * to call something else
  * @ops: The address of the struct ftrace_ops object
  * @addr: The address of the new trampoline to call at @ops functions
  *
  * This is used to unregister currently registered direct caller and
  * register new one @addr on functions registered in @ops object.
  *
  * Note there's window between ftrace_shutdown and ftrace_startup calls
  * where there will be no callbacks called.
  *
  * Returns: zero on success. Non zero on error, which includes:
  *  -EINVAL - The @ops object was not properly registered.
  */
 int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
     int err;
 
     if (check_direct_multi(ops))
         return -EINVAL;
     if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
         return -EINVAL;
 
     mutex_lock(&direct_mutex);
     err = __modify_ftrace_direct_multi(ops, addr);
     mutex_unlock(&direct_mutex);
     return err;
 }
 EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 /**
  * ftrace_set_filter_ip - set a function to filter on in ftrace by address
  * @ops - the ops to set the filter with
  * @ip - the address to add to or remove from the filter.
  * @remove - non zero to remove the ip from the filter
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Filters denote which functions should be enabled when tracing is enabled
  * If @ip is NULL, it fails to update filter.
  */
 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
              int remove, int reset)
 {
     ftrace_ops_init(ops);
     return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
 
 /**
  * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
  * @ops - the ops to set the filter with
  * @ips - the array of addresses to add to or remove from the filter.
  * @cnt - the number of addresses in @ips
  * @remove - non zero to remove ips from the filter
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Filters denote which functions should be enabled when tracing is enabled
  * If @ips array or any ip specified within is NULL , it fails to update filter.
  */
 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
               unsigned int cnt, int remove, int reset)
 {
     ftrace_ops_init(ops);
     return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
 
 /**
  * ftrace_ops_set_global_filter - setup ops to use global filters
  * @ops - the ops which will use the global filters
  *
  * ftrace users who need global function trace filtering should call this.
  * It can set the global filter only if ops were not initialized before.
  */
 void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
 {
     if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
         return;
 
     ftrace_ops_init(ops);
     ops->func_hash = &global_ops.local_hash;
 }
 EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
 
 static int
 ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
          int reset, int enable)
 {
     return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
 }
 
 /**
  * ftrace_set_filter - set a function to filter on in ftrace
  * @ops - the ops to set the filter with
  * @buf - the string that holds the function filter text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Filters denote which functions should be enabled when tracing is enabled.
  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
  */
 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
                int len, int reset)
 {
     ftrace_ops_init(ops);
     return ftrace_set_regex(ops, buf, len, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter);
 
 /**
  * ftrace_set_notrace - set a function to not trace in ftrace
  * @ops - the ops to set the notrace filter with
  * @buf - the string that holds the function notrace text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Notrace Filters denote which functions should not be enabled when tracing
  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
  * for tracing.
  */
 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
             int len, int reset)
 {
     ftrace_ops_init(ops);
     return ftrace_set_regex(ops, buf, len, reset, 0);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
 /**
  * ftrace_set_global_filter - set a function to filter on with global tracers
  * @buf - the string that holds the function filter text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Filters denote which functions should be enabled when tracing is enabled.
  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
  */
 void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
 {
     ftrace_set_regex(&global_ops, buf, len, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
 
 /**
  * ftrace_set_global_notrace - set a function to not trace with global tracers
  * @buf - the string that holds the function notrace text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Notrace Filters denote which functions should not be enabled when tracing
  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
  * for tracing.
  */
 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
 {
     ftrace_set_regex(&global_ops, buf, len, reset, 0);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
 
 /*
  * command line interface to allow users to set filters on boot up.
  */
 #define FTRACE_FILTER_SIZE      COMMAND_LINE_SIZE
 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
 
 /* Used by function selftest to not test if filter is set */
 bool ftrace_filter_param __initdata;
 
 static int __init set_ftrace_notrace(char *str)
 {
     ftrace_filter_param = true;
     strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
     return 1;
 }
 __setup("ftrace_notrace=", set_ftrace_notrace);
 
 static int __init set_ftrace_filter(char *str)
 {
     ftrace_filter_param = true;
     strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
     return 1;
 }
 __setup("ftrace_filter=", set_ftrace_filter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
 static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
 static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
 
 static int __init set_graph_function(char *str)
 {
     strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
     return 1;
 }
 __setup("ftrace_graph_filter=", set_graph_function);
 
 static int __init set_graph_notrace_function(char *str)
 {
     strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
     return 1;
 }
 __setup("ftrace_graph_notrace=", set_graph_notrace_function);
 
 static int __init set_graph_max_depth_function(char *str)
 {
     if (!str)
         return 0;
     fgraph_max_depth = simple_strtoul(str, NULL, 0);
     return 1;
 }
 __setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
 
 static void __init set_ftrace_early_graph(char *buf, int enable)
 {
     int ret;
     char *func;
     struct ftrace_hash *hash;
 
     hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
     if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
         return;
 
     while (buf) {
         func = strsep(&buf, ",");
         /* we allow only one expression at a time */
         ret = ftrace_graph_set_hash(hash, func);
         if (ret)
             printk(KERN_DEBUG "ftrace: function %s not "
                       "traceable\n", func);
     }
 
     if (enable)
         ftrace_graph_hash = hash;
     else
         ftrace_graph_notrace_hash = hash;
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 void __init
 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
 {
     char *func;
 
     ftrace_ops_init(ops);
 
     while (buf) {
         func = strsep(&buf, ",");
         ftrace_set_regex(ops, func, strlen(func), 0, enable);
     }
 }
 
 static void __init set_ftrace_early_filters(void)
 {
     if (ftrace_filter_buf[0])
         ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
     if (ftrace_notrace_buf[0])
         ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
     if (ftrace_graph_buf[0])
         set_ftrace_early_graph(ftrace_graph_buf, 1);
     if (ftrace_graph_notrace_buf[0])
         set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 }
 
 int ftrace_regex_release(struct inode *inode, struct file *file)
 {
     struct seq_file *m = (struct seq_file *)file->private_data;
     struct ftrace_iterator *iter;
     struct ftrace_hash **orig_hash;
     struct trace_parser *parser;
     int filter_hash;
 
     if (file->f_mode & FMODE_READ) {
         iter = m->private;
         seq_release(inode, file);
     } else
         iter = file->private_data;
 
     parser = &iter->parser;
     if (trace_parser_loaded(parser)) {
         int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
 
         ftrace_process_regex(iter, parser->buffer,
                      parser->idx, enable);
     }
 
     trace_parser_put(parser);
 
     mutex_lock(&iter->ops->func_hash->regex_lock);
 
     if (file->f_mode & FMODE_WRITE) {
         filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
 
         if (filter_hash) {
             orig_hash = &iter->ops->func_hash->filter_hash;
             if (iter->tr && !list_empty(&iter->tr->mod_trace))
                 iter->hash->flags |= FTRACE_HASH_FL_MOD;
         } else
             orig_hash = &iter->ops->func_hash->notrace_hash;
 
         mutex_lock(&ftrace_lock);
         ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
                               iter->hash, filter_hash);
         mutex_unlock(&ftrace_lock);
     } else {
         /* For read only, the hash is the ops hash */
         iter->hash = NULL;
     }
 
     mutex_unlock(&iter->ops->func_hash->regex_lock);
     free_ftrace_hash(iter->hash);
     if (iter->tr)
         trace_array_put(iter->tr);
     kfree(iter);
 
     return 0;
 }
 
 static const struct file_operations ftrace_avail_fops = {
     .open = ftrace_avail_open,
     .read = seq_read,
     .llseek = seq_lseek,
     .release = seq_release_private,
 };
 
 static const struct file_operations ftrace_enabled_fops = {
     .open = ftrace_enabled_open,
     .read = seq_read,
     .llseek = seq_lseek,
     .release = seq_release_private,
 };
 
 static const struct file_operations ftrace_filter_fops = {
     .open = ftrace_filter_open,
     .read = seq_read,
     .write = ftrace_filter_write,
     .llseek = tracing_lseek,
     .release = ftrace_regex_release,
 };
 
 static const struct file_operations ftrace_notrace_fops = {
     .open = ftrace_notrace_open,
     .read = seq_read,
     .write = ftrace_notrace_write,
     .llseek = tracing_lseek,
     .release = ftrace_regex_release,
 };
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 static DEFINE_MUTEX(graph_lock);
 
 struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
 struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
 
 enum graph_filter_type {
     GRAPH_FILTER_NOTRACE    = 0,
     GRAPH_FILTER_FUNCTION,
 };
 
 #define FTRACE_GRAPH_EMPTY  ((void *)1)
 
 struct ftrace_graph_data {
     struct ftrace_hash      *hash;
     struct ftrace_func_entry    *entry;
     int             idx;   /* for hash table iteration */
     enum graph_filter_type      type;
     struct ftrace_hash      *new_hash;
     const struct seq_operations *seq_ops;
     struct trace_parser     parser;
 };
 
 static void *
 __g_next(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_graph_data *fgd = m->private;
     struct ftrace_func_entry *entry = fgd->entry;
     struct hlist_head *head;
     int i, idx = fgd->idx;
 
     if (*pos >= fgd->hash->count)
         return NULL;
 
     if (entry) {
         hlist_for_each_entry_continue(entry, hlist) {
             fgd->entry = entry;
             return entry;
         }
 
         idx++;
     }
 
     for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
         head = &fgd->hash->buckets[i];
         hlist_for_each_entry(entry, head, hlist) {
             fgd->entry = entry;
             fgd->idx = i;
             return entry;
         }
     }
     return NULL;
 }
 
 static void *
 g_next(struct seq_file *m, void *v, loff_t *pos)
 {
     (*pos)++;
     return __g_next(m, pos);
 }
 
 static void *g_start(struct seq_file *m, loff_t *pos)
 {
     struct ftrace_graph_data *fgd = m->private;
 
     mutex_lock(&graph_lock);
 
     if (fgd->type == GRAPH_FILTER_FUNCTION)
         fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
                     lockdep_is_held(&graph_lock));
     else
         fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
                     lockdep_is_held(&graph_lock));
 
     /* Nothing, tell g_show to print all functions are enabled */
     if (ftrace_hash_empty(fgd->hash) && !*pos)
         return FTRACE_GRAPH_EMPTY;
 
     fgd->idx = 0;
     fgd->entry = NULL;
     return __g_next(m, pos);
 }
 
 static void g_stop(struct seq_file *m, void *p)
 {
     mutex_unlock(&graph_lock);
 }
 
 static int g_show(struct seq_file *m, void *v)
 {
     struct ftrace_func_entry *entry = v;
 
     if (!entry)
         return 0;
 
     if (entry == FTRACE_GRAPH_EMPTY) {
         struct ftrace_graph_data *fgd = m->private;
 
         if (fgd->type == GRAPH_FILTER_FUNCTION)
             seq_puts(m, "#### all functions enabled ####\n");
         else
             seq_puts(m, "#### no functions disabled ####\n");
         return 0;
     }
 
     seq_printf(m, "%ps\n", (void *)entry->ip);
 
     return 0;
 }
 
 static const struct seq_operations ftrace_graph_seq_ops = {
     .start = g_start,
     .next = g_next,
     .stop = g_stop,
     .show = g_show,
 };
 
 static int
 __ftrace_graph_open(struct inode *inode, struct file *file,
             struct ftrace_graph_data *fgd)
 {
     int ret;
     struct ftrace_hash *new_hash = NULL;
 
     ret = security_locked_down(LOCKDOWN_TRACEFS);
     if (ret)
         return ret;
 
     if (file->f_mode & FMODE_WRITE) {
         const int size_bits = FTRACE_HASH_DEFAULT_BITS;
 
         if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
             return -ENOMEM;
 
         if (file->f_flags & O_TRUNC)
             new_hash = alloc_ftrace_hash(size_bits);
         else
             new_hash = alloc_and_copy_ftrace_hash(size_bits,
                                   fgd->hash);
         if (!new_hash) {
             ret = -ENOMEM;
             goto out;
         }
     }
 
     if (file->f_mode & FMODE_READ) {
         ret = seq_open(file, &ftrace_graph_seq_ops);
         if (!ret) {
             struct seq_file *m = file->private_data;
             m->private = fgd;
         } else {
             /* Failed */
             free_ftrace_hash(new_hash);
             new_hash = NULL;
         }
     } else
         file->private_data = fgd;
 
 out:
     if (ret < 0 && file->f_mode & FMODE_WRITE)
         trace_parser_put(&fgd->parser);
 
     fgd->new_hash = new_hash;
 
     /*
      * All uses of fgd->hash must be taken with the graph_lock
      * held. The graph_lock is going to be released, so force
      * fgd->hash to be reinitialized when it is taken again.
      */
     fgd->hash = NULL;
 
     return ret;
 }
 
 static int
 ftrace_graph_open(struct inode *inode, struct file *file)
 {
     struct ftrace_graph_data *fgd;
     int ret;
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
     if (fgd == NULL)
         return -ENOMEM;
 
     mutex_lock(&graph_lock);
 
     fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
                     lockdep_is_held(&graph_lock));
     fgd->type = GRAPH_FILTER_FUNCTION;
     fgd->seq_ops = &ftrace_graph_seq_ops;
 
     ret = __ftrace_graph_open(inode, file, fgd);
     if (ret < 0)
         kfree(fgd);
 
     mutex_unlock(&graph_lock);
     return ret;
 }
 
 static int
 ftrace_graph_notrace_open(struct inode *inode, struct file *file)
 {
     struct ftrace_graph_data *fgd;
     int ret;
 
     if (unlikely(ftrace_disabled))
         return -ENODEV;
 
     fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
     if (fgd == NULL)
         return -ENOMEM;
 
     mutex_lock(&graph_lock);
 
     fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
                     lockdep_is_held(&graph_lock));
     fgd->type = GRAPH_FILTER_NOTRACE;
     fgd->seq_ops = &ftrace_graph_seq_ops;
 
     ret = __ftrace_graph_open(inode, file, fgd);
     if (ret < 0)
         kfree(fgd);
 
     mutex_unlock(&graph_lock);
     return ret;
 }
 
 static int
 ftrace_graph_release(struct inode *inode, struct file *file)
 {
     struct ftrace_graph_data *fgd;
     struct ftrace_hash *old_hash, *new_hash;
     struct trace_parser *parser;
     int ret = 0;
 
     if (file->f_mode & FMODE_READ) {
         struct seq_file *m = file->private_data;
 
         fgd = m->private;
         seq_release(inode, file);
     } else {
         fgd = file->private_data;
     }
 
 
     if (file->f_mode & FMODE_WRITE) {
 
         parser = &fgd->parser;
 
         if (trace_parser_loaded((parser))) {
             ret = ftrace_graph_set_hash(fgd->new_hash,
                             parser->buffer);
         }
 
         trace_parser_put(parser);
 
         new_hash = __ftrace_hash_move(fgd->new_hash);
         if (!new_hash) {
             ret = -ENOMEM;
             goto out;
         }
 
         mutex_lock(&graph_lock);
 
         if (fgd->type == GRAPH_FILTER_FUNCTION) {
             old_hash = rcu_dereference_protected(ftrace_graph_hash,
                     lockdep_is_held(&graph_lock));
             rcu_assign_pointer(ftrace_graph_hash, new_hash);
         } else {
             old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
                     lockdep_is_held(&graph_lock));
             rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
         }
 
         mutex_unlock(&graph_lock);
 
         /*
          * We need to do a hard force of sched synchronization.
          * This is because we use preempt_disable() to do RCU, but
          * the function tracers can be called where RCU is not watching
          * (like before user_exit()). We can not rely on the RCU
          * infrastructure to do the synchronization, thus we must do it
          * ourselves.
          */
         if (old_hash != EMPTY_HASH)
             synchronize_rcu_tasks_rude();
 
         free_ftrace_hash(old_hash);
     }
 
  out:
     free_ftrace_hash(fgd->new_hash);
     kfree(fgd);
 
     return ret;
 }
 
 static int
 ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
 {
     struct ftrace_glob func_g;
     struct dyn_ftrace *rec;
     struct ftrace_page *pg;
     struct ftrace_func_entry *entry;
     int fail = 1;
     int not;
 
     /* decode regex */
     func_g.type = filter_parse_regex(buffer, strlen(buffer),
                      &func_g.search, &not);
 
     func_g.len = strlen(func_g.search);
 
     mutex_lock(&ftrace_lock);
 
     if (unlikely(ftrace_disabled)) {
         mutex_unlock(&ftrace_lock);
         return -ENODEV;
     }
 
     do_for_each_ftrace_rec(pg, rec) {
 
         if (rec->flags & FTRACE_FL_DISABLED)
             continue;
 
         if (ftrace_match_record(rec, &func_g, NULL, 0)) {
             entry = ftrace_lookup_ip(hash, rec->ip);
 
             if (!not) {
                 fail = 0;
 
                 if (entry)
                     continue;
                 if (add_hash_entry(hash, rec->ip) < 0)
                     goto out;
             } else {
                 if (entry) {
                     free_hash_entry(hash, entry);
                     fail = 0;
                 }
             }
         }
     } while_for_each_ftrace_rec();
 out:
     mutex_unlock(&ftrace_lock);
 
     if (fail)
         return -EINVAL;
 
     return 0;
 }
 
 static ssize_t
 ftrace_graph_write(struct file *file, const char __user *ubuf,
            size_t cnt, loff_t *ppos)
 {
     ssize_t read, ret = 0;
     struct ftrace_graph_data *fgd = file->private_data;
     struct trace_parser *parser;
 
     if (!cnt)
         return 0;
 
     /* Read mode uses seq functions */
     if (file->f_mode & FMODE_READ) {
         struct seq_file *m = file->private_data;
         fgd = m->private;
     }
 
     parser = &fgd->parser;
 
     read = trace_get_user(parser, ubuf, cnt, ppos);
 
     if (read >= 0 && trace_parser_loaded(parser) &&
         !trace_parser_cont(parser)) {
 
         ret = ftrace_graph_set_hash(fgd->new_hash,
                         parser->buffer);
         trace_parser_clear(parser);
     }
 
     if (!ret)
         ret = read;
 
     return ret;
 }
 
 static const struct file_operations ftrace_graph_fops = {
     .open       = ftrace_graph_open,
     .read       = seq_read,
     .write      = ftrace_graph_write,
     .llseek     = tracing_lseek,
     .release    = ftrace_graph_release,
 };
 
 static const struct file_operations ftrace_graph_notrace_fops = {
     .open       = ftrace_graph_notrace_open,
     .read       = seq_read,
     .write      = ftrace_graph_write,
     .llseek     = tracing_lseek,
     .release    = ftrace_graph_release,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 void ftrace_create_filter_files(struct ftrace_ops *ops,
                 struct dentry *parent)
 {
 
     trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
               ops, &ftrace_filter_fops);
 
     trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
               ops, &ftrace_notrace_fops);
 }
 
 /*
  * The name "destroy_filter_files" is really a misnomer. Although
  * in the future, it may actually delete the files, but this is
  * really intended to make sure the ops passed in are disabled
  * and that when this function returns, the caller is free to
  * free the ops.
  *
  * The "destroy" name is only to match the "create" name that this
  * should be paired with.
  */
 void ftrace_destroy_filter_files(struct ftrace_ops *ops)
 {
     mutex_lock(&ftrace_lock);
     if (ops->flags & FTRACE_OPS_FL_ENABLED)
         ftrace_shutdown(ops, 0);
     ops->flags |= FTRACE_OPS_FL_DELETED;
     ftrace_free_filter(ops);
     mutex_unlock(&ftrace_lock);
 }
 
 static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
 {
 
     trace_create_file("available_filter_functions", TRACE_MODE_READ,
             d_tracer, NULL, &ftrace_avail_fops);
 
     trace_create_file("enabled_functions", TRACE_MODE_READ,
             d_tracer, NULL, &ftrace_enabled_fops);
 
     ftrace_create_filter_files(&global_ops, d_tracer);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
     trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
                     NULL,
                     &ftrace_graph_fops);
     trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
                     NULL,
                     &ftrace_graph_notrace_fops);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
     return 0;
 }
 
 static int ftrace_cmp_ips(const void *a, const void *b)
 {
     const unsigned long *ipa = a;
     const unsigned long *ipb = b;
 
     if (*ipa > *ipb)
         return 1;
     if (*ipa < *ipb)
         return -1;
     return 0;
 }
 
 #ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
 static void test_is_sorted(unsigned long *start, unsigned long count)
 {
     int i;
 
     for (i = 1; i < count; i++) {
         if (WARN(start[i - 1] > start[i],
              "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
              (void *)start[i - 1], start[i - 1],
              (void *)start[i], start[i]))
             break;
     }
     if (i == count)
         pr_info("ftrace section at %px sorted properly\n", start);
 }
 #else
 static void test_is_sorted(unsigned long *start, unsigned long count)
 {
 }
 #endif
 
 static int ftrace_process_locs(struct module *mod,
                    unsigned long *start,
                    unsigned long *end)
 {
     struct ftrace_page *start_pg;
     struct ftrace_page *pg;
     struct dyn_ftrace *rec;
     unsigned long count;
     unsigned long *p;
     unsigned long addr;
     unsigned long flags = 0; /* Shut up gcc */
     int ret = -ENOMEM;
 
     count = end - start;
 
     if (!count)
         return 0;
 
     /*
      * Sorting mcount in vmlinux at build time depend on
      * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
      * modules can not be sorted at build time.
      */
     if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
         sort(start, count, sizeof(*start),
              ftrace_cmp_ips, NULL);
     } else {
         test_is_sorted(start, count);
     }
 
     start_pg = ftrace_allocate_pages(count);
     if (!start_pg)
         return -ENOMEM;
 
     mutex_lock(&ftrace_lock);
 
     /*
      * Core and each module needs their own pages, as
      * modules will free them when they are removed.
      * Force a new page to be allocated for modules.
      */
     if (!mod) {
         WARN_ON(ftrace_pages || ftrace_pages_start);
         /* First initialization */
         ftrace_pages = ftrace_pages_start = start_pg;
     } else {
         if (!ftrace_pages)
             goto out;
 
         if (WARN_ON(ftrace_pages->next)) {
             /* Hmm, we have free pages? */
             while (ftrace_pages->next)
                 ftrace_pages = ftrace_pages->next;
         }
 
         ftrace_pages->next = start_pg;
     }
 
     p = start;
     pg = start_pg;
     while (p < end) {
         unsigned long end_offset;
         addr = ftrace_call_adjust(*p++);
         /*
          * Some architecture linkers will pad between
          * the different mcount_loc sections of different
          * object files to satisfy alignments.
          * Skip any NULL pointers.
          */
         if (!addr)
             continue;
 
         end_offset = (pg->index+1) * sizeof(pg->records[0]);
         if (end_offset > PAGE_SIZE << pg->order) {
             /* We should have allocated enough */
             if (WARN_ON(!pg->next))
                 break;
             pg = pg->next;
         }
 
         rec = &pg->records[pg->index++];
         rec->ip = addr;
     }
 
     /* We should have used all pages */
     WARN_ON(pg->next);
 
     /* Assign the last page to ftrace_pages */
     ftrace_pages = pg;
 
     /*
      * We only need to disable interrupts on start up
      * because we are modifying code that an interrupt
      * may execute, and the modification is not atomic.
      * But for modules, nothing runs the code we modify
      * until we are finished with it, and there's no
      * reason to cause large interrupt latencies while we do it.
      */
     if (!mod)
         local_irq_save(flags);
     ftrace_update_code(mod, start_pg);
     if (!mod)
         local_irq_restore(flags);
     ret = 0;
  out:
     mutex_unlock(&ftrace_lock);
 
     return ret;
 }
 
 struct ftrace_mod_func {
     struct list_head    list;
     char            *name;
     unsigned long       ip;
     unsigned int        size;
 };
 
 struct ftrace_mod_map {
     struct rcu_head     rcu;
     struct list_head    list;
     struct module       *mod;
     unsigned long       start_addr;
     unsigned long       end_addr;
     struct list_head    funcs;
     unsigned int        num_funcs;
 };
 
 static int ftrace_get_trampoline_kallsym(unsigned int symnum,
                      unsigned long *value, char *type,
                      char *name, char *module_name,
                      int *exported)
 {
     struct ftrace_ops *op;
 
     list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
         if (!op->trampoline || symnum--)
             continue;
         *value = op->trampoline;
         *type = 't';
         strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
         strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
         *exported = 0;
         return 0;
     }
 
     return -ERANGE;
 }
 
 #if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
 /*
  * Check if the current ops references the given ip.
  *
  * If the ops traces all functions, then it was already accounted for.
  * If the ops does not trace the current record function, skip it.
  * If the ops ignores the function via notrace filter, skip it.
  */
 static bool
 ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
 {
     /* If ops isn't enabled, ignore it */
     if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
         return false;
 
     /* If ops traces all then it includes this function */
     if (ops_traces_mod(ops))
         return true;
 
     /* The function must be in the filter */
     if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
         !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
         return false;
 
     /* If in notrace hash, we ignore it too */
     if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
         return false;
 
     return true;
 }
 #endif
 
 #ifdef CONFIG_MODULES
 
 #define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
 
 static LIST_HEAD(ftrace_mod_maps);
 
 static int referenced_filters(struct dyn_ftrace *rec)
 {
     struct ftrace_ops *ops;
     int cnt = 0;
 
     for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
         if (ops_references_ip(ops, rec->ip)) {
             if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
                 continue;
             if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
                 continue;
             cnt++;
             if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
                 rec->flags |= FTRACE_FL_REGS;
             if (cnt == 1 && ops->trampoline)
                 rec->flags |= FTRACE_FL_TRAMP;
             else
                 rec->flags &= ~FTRACE_FL_TRAMP;
         }
     }
 
     return cnt;
 }
 
 static void
 clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
 {
     struct ftrace_func_entry *entry;
     struct dyn_ftrace *rec;
     int i;
 
     if (ftrace_hash_empty(hash))
         return;
 
     for (i = 0; i < pg->index; i++) {
         rec = &pg->records[i];
         entry = __ftrace_lookup_ip(hash, rec->ip);
         /*
          * Do not allow this rec to match again.
          * Yeah, it may waste some memory, but will be removed
          * if/when the hash is modified again.
          */
         if (entry)
             entry->ip = 0;
     }
 }
 
 /* Clear any records from hashes */
 static void clear_mod_from_hashes(struct ftrace_page *pg)
 {
     struct trace_array *tr;
 
     mutex_lock(&trace_types_lock);
     list_for_each_entry(tr, &ftrace_trace_arrays, list) {
         if (!tr->ops || !tr->ops->func_hash)
             continue;
         mutex_lock(&tr->ops->func_hash->regex_lock);
         clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
         clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
         mutex_unlock(&tr->ops->func_hash->regex_lock);
     }
     mutex_unlock(&trace_types_lock);
 }
 
 static void ftrace_free_mod_map(struct rcu_head *rcu)
 {
     struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
     struct ftrace_mod_func *mod_func;
     struct ftrace_mod_func *n;
 
     /* All the contents of mod_map are now not visible to readers */
     list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
         kfree(mod_func->name);
         list_del(&mod_func->list);
         kfree(mod_func);
     }
 
     kfree(mod_map);
 }
 
 void ftrace_release_mod(struct module *mod)
 {
     struct ftrace_mod_map *mod_map;
     struct ftrace_mod_map *n;
     struct dyn_ftrace *rec;
     struct ftrace_page **last_pg;
     struct ftrace_page *tmp_page = NULL;
     struct ftrace_page *pg;
 
     mutex_lock(&ftrace_lock);
 
     if (ftrace_disabled)
         goto out_unlock;
 
     list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
         if (mod_map->mod == mod) {
             list_del_rcu(&mod_map->list);
             call_rcu(&mod_map->rcu, ftrace_free_mod_map);
             break;
         }
     }
 
     /*
      * Each module has its own ftrace_pages, remove
      * them from the list.
      */
     last_pg = &ftrace_pages_start;
     for (pg = ftrace_pages_start; pg; pg = *last_pg) {
         rec = &pg->records[0];
         if (within_module_core(rec->ip, mod) ||
             within_module_init(rec->ip, mod)) {
             /*
              * As core pages are first, the first
              * page should never be a module page.
              */
             if (WARN_ON(pg == ftrace_pages_start))
                 goto out_unlock;
 
             /* Check if we are deleting the last page */
             if (pg == ftrace_pages)
                 ftrace_pages = next_to_ftrace_page(last_pg);
 
             ftrace_update_tot_cnt -= pg->index;
             *last_pg = pg->next;
 
             pg->next = tmp_page;
             tmp_page = pg;
         } else
             last_pg = &pg->next;
     }
  out_unlock:
     mutex_unlock(&ftrace_lock);
 
     for (pg = tmp_page; pg; pg = tmp_page) {
 
         /* Needs to be called outside of ftrace_lock */
         clear_mod_from_hashes(pg);
 
         if (pg->records) {
             free_pages((unsigned long)pg->records, pg->order);
             ftrace_number_of_pages -= 1 << pg->order;
         }
         tmp_page = pg->next;
         kfree(pg);
         ftrace_number_of_groups--;
     }
 }
 
 void ftrace_module_enable(struct module *mod)
 {
     struct dyn_ftrace *rec;
     struct ftrace_page *pg;
 
     mutex_lock(&ftrace_lock);
 
     if (ftrace_disabled)
         goto out_unlock;
 
     /*
      * If the tracing is enabled, go ahead and enable the record.
      *
      * The reason not to enable the record immediately is the
      * inherent check of ftrace_make_nop/ftrace_make_call for
      * correct previous instructions.  Making first the NOP
      * conversion puts the module to the correct state, thus
      * passing the ftrace_make_call check.
      *
      * We also delay this to after the module code already set the
      * text to read-only, as we now need to set it back to read-write
      * so that we can modify the text.
      */
     if (ftrace_start_up)
         ftrace_arch_code_modify_prepare();
 
     do_for_each_ftrace_rec(pg, rec) {
         int cnt;
         /*
          * do_for_each_ftrace_rec() is a double loop.
          * module text shares the pg. If a record is
          * not part of this module, then skip this pg,
          * which the "break" will do.
          */
         if (!within_module_core(rec->ip, mod) &&
             !within_module_init(rec->ip, mod))
             break;
 
         /* Weak functions should still be ignored */
         if (!test_for_valid_rec(rec)) {
             /* Clear all other flags. Should not be enabled anyway */
             rec->flags = FTRACE_FL_DISABLED;
             continue;
         }
 
         cnt = 0;
 
         /*
          * When adding a module, we need to check if tracers are
          * currently enabled and if they are, and can trace this record,
          * we need to enable the module functions as well as update the
          * reference counts for those function records.
          */
         if (ftrace_start_up)
             cnt += referenced_filters(rec);
 
         rec->flags &= ~FTRACE_FL_DISABLED;
         rec->flags += cnt;
 
         if (ftrace_start_up && cnt) {
             int failed = __ftrace_replace_code(rec, 1);
             if (failed) {
                 ftrace_bug(failed, rec);
                 goto out_loop;
             }
         }
 
     } while_for_each_ftrace_rec();
 
  out_loop:
     if (ftrace_start_up)
         ftrace_arch_code_modify_post_process();
 
  out_unlock:
     mutex_unlock(&ftrace_lock);
 
     process_cached_mods(mod->name);
 }
 
 void ftrace_module_init(struct module *mod)
 {
     int ret;
 
     if (ftrace_disabled || !mod->num_ftrace_callsites)
         return;
 
     ret = ftrace_process_locs(mod, mod->ftrace_callsites,
                   mod->ftrace_callsites + mod->num_ftrace_callsites);
     if (ret)
         pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
             mod->name);
 }
 
 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
                 struct dyn_ftrace *rec)
 {
     struct ftrace_mod_func *mod_func;
     unsigned long symsize;
     unsigned long offset;
     char str[KSYM_SYMBOL_LEN];
     char *modname;
     const char *ret;
 
     ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
     if (!ret)
         return;
 
     mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
     if (!mod_func)
         return;
 
     mod_func->name = kstrdup(str, GFP_KERNEL);
     if (!mod_func->name) {
         kfree(mod_func);
         return;
     }
 
     mod_func->ip = rec->ip - offset;
     mod_func->size = symsize;
 
     mod_map->num_funcs++;
 
     list_add_rcu(&mod_func->list, &mod_map->funcs);
 }
 
 static struct ftrace_mod_map *
 allocate_ftrace_mod_map(struct module *mod,
             unsigned long start, unsigned long end)
 {
     struct ftrace_mod_map *mod_map;
 
     mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
     if (!mod_map)
         return NULL;
 
     mod_map->mod = mod;
     mod_map->start_addr = start;
     mod_map->end_addr = end;
     mod_map->num_funcs = 0;
 
     INIT_LIST_HEAD_RCU(&mod_map->funcs);
 
     list_add_rcu(&mod_map->list, &ftrace_mod_maps);
 
     return mod_map;
 }
 
 static const char *
 ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
                unsigned long addr, unsigned long *size,
                unsigned long *off, char *sym)
 {
     struct ftrace_mod_func *found_func =  NULL;
     struct ftrace_mod_func *mod_func;
 
     list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
         if (addr >= mod_func->ip &&
             addr < mod_func->ip + mod_func->size) {
             found_func = mod_func;
             break;
         }
     }
 
     if (found_func) {
         if (size)
             *size = found_func->size;
         if (off)
             *off = addr - found_func->ip;
         if (sym)
             strlcpy(sym, found_func->name, KSYM_NAME_LEN);
 
         return found_func->name;
     }
 
     return NULL;
 }
 
 const char *
 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
            unsigned long *off, char **modname, char *sym)
 {
     struct ftrace_mod_map *mod_map;
     const char *ret = NULL;
 
     /* mod_map is freed via call_rcu() */
     preempt_disable();
     list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
         ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
         if (ret) {
             if (modname)
                 *modname = mod_map->mod->name;
             break;
         }
     }
     preempt_enable();
 
     return ret;
 }
 
 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
                char *type, char *name,
                char *module_name, int *exported)
 {
     struct ftrace_mod_map *mod_map;
     struct ftrace_mod_func *mod_func;
     int ret;
 
     preempt_disable();
     list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
 
         if (symnum >= mod_map->num_funcs) {
             symnum -= mod_map->num_funcs;
             continue;
         }
 
         list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
             if (symnum > 1) {
                 symnum--;
                 continue;
             }
 
             *value = mod_func->ip;
             *type = 'T';
             strlcpy(name, mod_func->name, KSYM_NAME_LEN);
             strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
             *exported = 1;
             preempt_enable();
             return 0;
         }
         WARN_ON(1);
         break;
     }
     ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
                         module_name, exported);
     preempt_enable();
     return ret;
 }
 
 #else
 static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
                 struct dyn_ftrace *rec) { }
 static inline struct ftrace_mod_map *
 allocate_ftrace_mod_map(struct module *mod,
             unsigned long start, unsigned long end)
 {
     return NULL;
 }
 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
                char *type, char *name, char *module_name,
                int *exported)
 {
     int ret;
 
     preempt_disable();
     ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
                         module_name, exported);
     preempt_enable();
     return ret;
 }
 #endif /* CONFIG_MODULES */
 
 struct ftrace_init_func {
     struct list_head list;
     unsigned long ip;
 };
 
 /* Clear any init ips from hashes */
 static void
 clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
 {
     struct ftrace_func_entry *entry;
 
     entry = ftrace_lookup_ip(hash, func->ip);
     /*
      * Do not allow this rec to match again.
      * Yeah, it may waste some memory, but will be removed
      * if/when the hash is modified again.
      */
     if (entry)
         entry->ip = 0;
 }
 
 static void
 clear_func_from_hashes(struct ftrace_init_func *func)
 {
     struct trace_array *tr;
 
     mutex_lock(&trace_types_lock);
     list_for_each_entry(tr, &ftrace_trace_arrays, list) {
         if (!tr->ops || !tr->ops->func_hash)
             continue;
         mutex_lock(&tr->ops->func_hash->regex_lock);
         clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
         clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
         mutex_unlock(&tr->ops->func_hash->regex_lock);
     }
     mutex_unlock(&trace_types_lock);
 }
 
 static void add_to_clear_hash_list(struct list_head *clear_list,
                    struct dyn_ftrace *rec)
 {
     struct ftrace_init_func *func;
 
     func = kmalloc(sizeof(*func), GFP_KERNEL);
     if (!func) {
         MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
         return;
     }
 
     func->ip = rec->ip;
     list_add(&func->list, clear_list);
 }
 
 void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
 {
     unsigned long start = (unsigned long)(start_ptr);
     unsigned long end = (unsigned long)(end_ptr);
     struct ftrace_page **last_pg = &ftrace_pages_start;
     struct ftrace_page *pg;
     struct dyn_ftrace *rec;
     struct dyn_ftrace key;
     struct ftrace_mod_map *mod_map = NULL;
     struct ftrace_init_func *func, *func_next;
     struct list_head clear_hash;
 
     INIT_LIST_HEAD(&clear_hash);
 
     key.ip = start;
     key.flags = end;    /* overload flags, as it is unsigned long */
 
     mutex_lock(&ftrace_lock);
 
     /*
      * If we are freeing module init memory, then check if
      * any tracer is active. If so, we need to save a mapping of
      * the module functions being freed with the address.
      */
     if (mod && ftrace_ops_list != &ftrace_list_end)
         mod_map = allocate_ftrace_mod_map(mod, start, end);
 
     for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
         if (end < pg->records[0].ip ||
             start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
             continue;
  again:
         rec = bsearch(&key, pg->records, pg->index,
                   sizeof(struct dyn_ftrace),
                   ftrace_cmp_recs);
         if (!rec)
             continue;
 
         /* rec will be cleared from hashes after ftrace_lock unlock */
         add_to_clear_hash_list(&clear_hash, rec);
 
         if (mod_map)
             save_ftrace_mod_rec(mod_map, rec);
 
         pg->index--;
         ftrace_update_tot_cnt--;
         if (!pg->index) {
             *last_pg = pg->next;
             if (pg->records) {
                 free_pages((unsigned long)pg->records, pg->order);
                 ftrace_number_of_pages -= 1 << pg->order;
             }
             ftrace_number_of_groups--;
             kfree(pg);
             pg = container_of(last_pg, struct ftrace_page, next);
             if (!(*last_pg))
                 ftrace_pages = pg;
             continue;
         }
         memmove(rec, rec + 1,
             (pg->index - (rec - pg->records)) * sizeof(*rec));
         /* More than one function may be in this block */
         goto again;
     }
     mutex_unlock(&ftrace_lock);
 
     list_for_each_entry_safe(func, func_next, &clear_hash, list) {
         clear_func_from_hashes(func);
         kfree(func);
     }
 }
 
 void __init ftrace_free_init_mem(void)
 {
     void *start = (void *)(&__init_begin);
     void *end = (void *)(&__init_end);
 
     ftrace_boot_snapshot();
 
     ftrace_free_mem(NULL, start, end);
 }
 
 int __init __weak ftrace_dyn_arch_init(void)
 {
     return 0;
 }
 
 void __init ftrace_init(void)
 {
     extern unsigned long __start_mcount_loc[];
     extern unsigned long __stop_mcount_loc[];
     unsigned long count, flags;
     int ret;
 
     local_irq_save(flags);
     ret = ftrace_dyn_arch_init();
     local_irq_restore(flags);
     if (ret)
         goto failed;
 
     count = __stop_mcount_loc - __start_mcount_loc;
     if (!count) {
         pr_info("ftrace: No functions to be traced?\n");
         goto failed;
     }
 
     pr_info("ftrace: allocating %ld entries in %ld pages\n",
         count, count / ENTRIES_PER_PAGE + 1);
 
     ret = ftrace_process_locs(NULL,
                   __start_mcount_loc,
                   __stop_mcount_loc);
     if (ret) {
         pr_warn("ftrace: failed to allocate entries for functions\n");
         goto failed;
     }
 
     pr_info("ftrace: allocated %ld pages with %ld groups\n",
         ftrace_number_of_pages, ftrace_number_of_groups);
 
     last_ftrace_enabled = ftrace_enabled = 1;
 
     set_ftrace_early_filters();
 
     return;
  failed:
     ftrace_disabled = 1;
 }
 
 /* Do nothing if arch does not support this */
 void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
 {
 }
 
 static void ftrace_update_trampoline(struct ftrace_ops *ops)
 {
     unsigned long trampoline = ops->trampoline;
 
     arch_ftrace_update_trampoline(ops);
     if (ops->trampoline && ops->trampoline != trampoline &&
         (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
         /* Add to kallsyms before the perf events */
         ftrace_add_trampoline_to_kallsyms(ops);
         perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
                    ops->trampoline, ops->trampoline_size, false,
                    FTRACE_TRAMPOLINE_SYM);
         /*
          * Record the perf text poke event after the ksymbol register
          * event.
          */
         perf_event_text_poke((void *)ops->trampoline, NULL, 0,
                      (void *)ops->trampoline,
                      ops->trampoline_size);
     }
 }
 
 void ftrace_init_trace_array(struct trace_array *tr)
 {
     INIT_LIST_HEAD(&tr->func_probes);
     INIT_LIST_HEAD(&tr->mod_trace);
     INIT_LIST_HEAD(&tr->mod_notrace);
 }
 #else
 
 struct ftrace_ops global_ops = {
     .func           = ftrace_stub,
     .flags          = FTRACE_OPS_FL_INITIALIZED |
                   FTRACE_OPS_FL_PID,
 };
 
 static int __init ftrace_nodyn_init(void)
 {
     ftrace_enabled = 1;
     return 0;
 }
 core_initcall(ftrace_nodyn_init);
 
 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
 static inline void ftrace_startup_all(int command) { }
 
 static void ftrace_update_trampoline(struct ftrace_ops *ops)
 {
 }
 
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 __init void ftrace_init_global_array_ops(struct trace_array *tr)
 {
     tr->ops = &global_ops;
     tr->ops->private = tr;
     ftrace_init_trace_array(tr);
 }
 
 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
 {
     /* If we filter on pids, update to use the pid function */
     if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
         if (WARN_ON(tr->ops->func != ftrace_stub))
             printk("ftrace ops had %pS for function\n",
                    tr->ops->func);
     }
     tr->ops->func = func;
     tr->ops->private = tr;
 }
 
 void ftrace_reset_array_ops(struct trace_array *tr)
 {
     tr->ops->func = ftrace_stub;
 }
 
 static nokprobe_inline void
 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
                struct ftrace_ops *ignored, struct ftrace_regs *fregs)
 {
     struct pt_regs *regs = ftrace_get_regs(fregs);
     struct ftrace_ops *op;
     int bit;
 
     /*
      * The ftrace_test_and_set_recursion() will disable preemption,
      * which is required since some of the ops may be dynamically
      * allocated, they must be freed after a synchronize_rcu().
      */
     bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
     if (bit < 0)
         return;
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
         /* Stub functions don't need to be called nor tested */
         if (op->flags & FTRACE_OPS_FL_STUB)
             continue;
         /*
          * Check the following for each ops before calling their func:
          *  if RCU flag is set, then rcu_is_watching() must be true
          *  if PER_CPU is set, then ftrace_function_local_disable()
          *                          must be false
          *  Otherwise test if the ip matches the ops filter
          *
          * If any of the above fails then the op->func() is not executed.
          */
         if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
             ftrace_ops_test(op, ip, regs)) {
             if (FTRACE_WARN_ON(!op->func)) {
                 pr_warn("op=%p %pS\n", op, op);
                 goto out;
             }
             op->func(ip, parent_ip, op, fregs);
         }
     } while_for_each_ftrace_op(op);
 out:
     trace_clear_recursion(bit);
 }
 
 /*
  * Some archs only support passing ip and parent_ip. Even though
  * the list function ignores the op parameter, we do not want any
  * C side effects, where a function is called without the caller
  * sending a third parameter.
  * Archs are to support both the regs and ftrace_ops at the same time.
  * If they support ftrace_ops, it is assumed they support regs.
  * If call backs want to use regs, they must either check for regs
  * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
  * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
  * An architecture can pass partial regs with ftrace_ops and still
  * set the ARCH_SUPPORTS_FTRACE_OPS.
  *
  * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
  * arch_ftrace_ops_list_func.
  */
 #if ARCH_SUPPORTS_FTRACE_OPS
 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
                    struct ftrace_ops *op, struct ftrace_regs *fregs)
 {
     __ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
 }
 #else
 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
 {
     __ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
 }
 #endif
 NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
 
 /*
  * If there's only one function registered but it does not support
  * recursion, needs RCU protection and/or requires per cpu handling, then
  * this function will be called by the mcount trampoline.
  */
 static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
                    struct ftrace_ops *op, struct ftrace_regs *fregs)
 {
     int bit;
 
     bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
     if (bit < 0)
         return;
 
     if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
         op->func(ip, parent_ip, op, fregs);
 
     trace_clear_recursion(bit);
 }
 NOKPROBE_SYMBOL(ftrace_ops_assist_func);
 
 /**
  * ftrace_ops_get_func - get the function a trampoline should call
  * @ops: the ops to get the function for
  *
  * Normally the mcount trampoline will call the ops->func, but there
  * are times that it should not. For example, if the ops does not
  * have its own recursion protection, then it should call the
  * ftrace_ops_assist_func() instead.
  *
  * Returns the function that the trampoline should call for @ops.
  */
 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
 {
     /*
      * If the function does not handle recursion or needs to be RCU safe,
      * then we need to call the assist handler.
      */
     if (ops->flags & (FTRACE_OPS_FL_RECURSION |
               FTRACE_OPS_FL_RCU))
         return ftrace_ops_assist_func;
 
     return ops->func;
 }
 
 static void
 ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
                      struct task_struct *prev,
                      struct task_struct *next,
                      unsigned int prev_state)
 {
     struct trace_array *tr = data;
     struct trace_pid_list *pid_list;
     struct trace_pid_list *no_pid_list;
 
     pid_list = rcu_dereference_sched(tr->function_pids);
     no_pid_list = rcu_dereference_sched(tr->function_no_pids);
 
     if (trace_ignore_this_task(pid_list, no_pid_list, next))
         this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
                    FTRACE_PID_IGNORE);
     else
         this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
                    next->pid);
 }
 
 static void
 ftrace_pid_follow_sched_process_fork(void *data,
                      struct task_struct *self,
                      struct task_struct *task)
 {
     struct trace_pid_list *pid_list;
     struct trace_array *tr = data;
 
     pid_list = rcu_dereference_sched(tr->function_pids);
     trace_filter_add_remove_task(pid_list, self, task);
 
     pid_list = rcu_dereference_sched(tr->function_no_pids);
     trace_filter_add_remove_task(pid_list, self, task);
 }
 
 static void
 ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
 {
     struct trace_pid_list *pid_list;
     struct trace_array *tr = data;
 
     pid_list = rcu_dereference_sched(tr->function_pids);
     trace_filter_add_remove_task(pid_list, NULL, task);
 
     pid_list = rcu_dereference_sched(tr->function_no_pids);
     trace_filter_add_remove_task(pid_list, NULL, task);
 }
 
 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
 {
     if (enable) {
         register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
                           tr);
         register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
                           tr);
     } else {
         unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
                             tr);
         unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
                             tr);
     }
 }
 
 static void clear_ftrace_pids(struct trace_array *tr, int type)
 {
     struct trace_pid_list *pid_list;
     struct trace_pid_list *no_pid_list;
     int cpu;
 
     pid_list = rcu_dereference_protected(tr->function_pids,
                          lockdep_is_held(&ftrace_lock));
     no_pid_list = rcu_dereference_protected(tr->function_no_pids,
                         lockdep_is_held(&ftrace_lock));
 
     /* Make sure there's something to do */
     if (!pid_type_enabled(type, pid_list, no_pid_list))
         return;
 
     /* See if the pids still need to be checked after this */
     if (!still_need_pid_events(type, pid_list, no_pid_list)) {
         unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
         for_each_possible_cpu(cpu)
             per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
     }
 
     if (type & TRACE_PIDS)
         rcu_assign_pointer(tr->function_pids, NULL);
 
     if (type & TRACE_NO_PIDS)
         rcu_assign_pointer(tr->function_no_pids, NULL);
 
     /* Wait till all users are no longer using pid filtering */
     synchronize_rcu();
 
     if ((type & TRACE_PIDS) && pid_list)
         trace_pid_list_free(pid_list);
 
     if ((type & TRACE_NO_PIDS) && no_pid_list)
         trace_pid_list_free(no_pid_list);
 }
 
 void ftrace_clear_pids(struct trace_array *tr)
 {
     mutex_lock(&ftrace_lock);
 
     clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
 
     mutex_unlock(&ftrace_lock);
 }
 
 static void ftrace_pid_reset(struct trace_array *tr, int type)
 {
     mutex_lock(&ftrace_lock);
     clear_ftrace_pids(tr, type);
 
     ftrace_update_pid_func();
     ftrace_startup_all(0);
 
     mutex_unlock(&ftrace_lock);
 }
 
 /* Greater than any max PID */
 #define FTRACE_NO_PIDS      (void *)(PID_MAX_LIMIT + 1)
 
 static void *fpid_start(struct seq_file *m, loff_t *pos)
     __acquires(RCU)
 {
     struct trace_pid_list *pid_list;
     struct trace_array *tr = m->private;
 
     mutex_lock(&ftrace_lock);
     rcu_read_lock_sched();
 
     pid_list = rcu_dereference_sched(tr->function_pids);
 
     if (!pid_list)
         return !(*pos) ? FTRACE_NO_PIDS : NULL;
 
     return trace_pid_start(pid_list, pos);
 }
 
 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
 {
     struct trace_array *tr = m->private;
     struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
 
     if (v == FTRACE_NO_PIDS) {
         (*pos)++;
         return NULL;
     }
     return trace_pid_next(pid_list, v, pos);
 }
 
 static void fpid_stop(struct seq_file *m, void *p)
     __releases(RCU)
 {
     rcu_read_unlock_sched();
     mutex_unlock(&ftrace_lock);
 }
 
 static int fpid_show(struct seq_file *m, void *v)
 {
     if (v == FTRACE_NO_PIDS) {
         seq_puts(m, "no pid\n");
         return 0;
     }
 
     return trace_pid_show(m, v);
 }
 
 static const struct seq_operations ftrace_pid_sops = {
     .start = fpid_start,
     .next = fpid_next,
     .stop = fpid_stop,
     .show = fpid_show,
 };
 
 static void *fnpid_start(struct seq_file *m, loff_t *pos)
     __acquires(RCU)
 {
     struct trace_pid_list *pid_list;
     struct trace_array *tr = m->private;
 
     mutex_lock(&ftrace_lock);
     rcu_read_lock_sched();
 
     pid_list = rcu_dereference_sched(tr->function_no_pids);
 
     if (!pid_list)
         return !(*pos) ? FTRACE_NO_PIDS : NULL;
 
     return trace_pid_start(pid_list, pos);
 }
 
 static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
 {
     struct trace_array *tr = m->private;
     struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
 
     if (v == FTRACE_NO_PIDS) {
         (*pos)++;
         return NULL;
     }
     return trace_pid_next(pid_list, v, pos);
 }
 
 static const struct seq_operations ftrace_no_pid_sops = {
     .start = fnpid_start,
     .next = fnpid_next,
     .stop = fpid_stop,
     .show = fpid_show,
 };
 
 static int pid_open(struct inode *inode, struct file *file, int type)
 {
     const struct seq_operations *seq_ops;
     struct trace_array *tr = inode->i_private;
     struct seq_file *m;
     int ret = 0;
 
     ret = tracing_check_open_get_tr(tr);
     if (ret)
         return ret;
 
     if ((file->f_mode & FMODE_WRITE) &&
         (file->f_flags & O_TRUNC))
         ftrace_pid_reset(tr, type);
 
     switch (type) {
     case TRACE_PIDS:
         seq_ops = &ftrace_pid_sops;
         break;
     case TRACE_NO_PIDS:
         seq_ops = &ftrace_no_pid_sops;
         break;
     default:
         trace_array_put(tr);
         WARN_ON_ONCE(1);
         return -EINVAL;
     }
 
     ret = seq_open(file, seq_ops);
     if (ret < 0) {
         trace_array_put(tr);
     } else {
         m = file->private_data;
         /* copy tr over to seq ops */
         m->private = tr;
     }
 
     return ret;
 }
 
 static int
 ftrace_pid_open(struct inode *inode, struct file *file)
 {
     return pid_open(inode, file, TRACE_PIDS);
 }
 
 static int
 ftrace_no_pid_open(struct inode *inode, struct file *file)
 {
     return pid_open(inode, file, TRACE_NO_PIDS);
 }
 
 static void ignore_task_cpu(void *data)
 {
     struct trace_array *tr = data;
     struct trace_pid_list *pid_list;
     struct trace_pid_list *no_pid_list;
 
     /*
      * This function is called by on_each_cpu() while the
      * event_mutex is held.
      */
     pid_list = rcu_dereference_protected(tr->function_pids,
                          mutex_is_locked(&ftrace_lock));
     no_pid_list = rcu_dereference_protected(tr->function_no_pids,
                         mutex_is_locked(&ftrace_lock));
 
     if (trace_ignore_this_task(pid_list, no_pid_list, current))
         this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
                    FTRACE_PID_IGNORE);
     else
         this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
                    current->pid);
 }
 
 static ssize_t
 pid_write(struct file *filp, const char __user *ubuf,
       size_t cnt, loff_t *ppos, int type)
 {
     struct seq_file *m = filp->private_data;
     struct trace_array *tr = m->private;
     struct trace_pid_list *filtered_pids;
     struct trace_pid_list *other_pids;
     struct trace_pid_list *pid_list;
     ssize_t ret;
 
     if (!cnt)
         return 0;
 
     mutex_lock(&ftrace_lock);
 
     switch (type) {
     case TRACE_PIDS:
         filtered_pids = rcu_dereference_protected(tr->function_pids,
                          lockdep_is_held(&ftrace_lock));
         other_pids = rcu_dereference_protected(tr->function_no_pids,
                          lockdep_is_held(&ftrace_lock));
         break;
     case TRACE_NO_PIDS:
         filtered_pids = rcu_dereference_protected(tr->function_no_pids,
                          lockdep_is_held(&ftrace_lock));
         other_pids = rcu_dereference_protected(tr->function_pids,
                          lockdep_is_held(&ftrace_lock));
         break;
     default:
         ret = -EINVAL;
         WARN_ON_ONCE(1);
         goto out;
     }
 
     ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
     if (ret < 0)
         goto out;
 
     switch (type) {
     case TRACE_PIDS:
         rcu_assign_pointer(tr->function_pids, pid_list);
         break;
     case TRACE_NO_PIDS:
         rcu_assign_pointer(tr->function_no_pids, pid_list);
         break;
     }
 
 
     if (filtered_pids) {
         synchronize_rcu();
         trace_pid_list_free(filtered_pids);
     } else if (pid_list && !other_pids) {
         /* Register a probe to set whether to ignore the tracing of a task */
         register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
     }
 
     /*
      * Ignoring of pids is done at task switch. But we have to
      * check for those tasks that are currently running.
      * Always do this in case a pid was appended or removed.
      */
     on_each_cpu(ignore_task_cpu, tr, 1);
 
     ftrace_update_pid_func();
     ftrace_startup_all(0);
  out:
     mutex_unlock(&ftrace_lock);
 
     if (ret > 0)
         *ppos += ret;
 
     return ret;
 }
 
 static ssize_t
 ftrace_pid_write(struct file *filp, const char __user *ubuf,
          size_t cnt, loff_t *ppos)
 {
     return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
 }
 
 static ssize_t
 ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
             size_t cnt, loff_t *ppos)
 {
     return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
 }
 
 static int
 ftrace_pid_release(struct inode *inode, struct file *file)
 {
     struct trace_array *tr = inode->i_private;
 
     trace_array_put(tr);
 
     return seq_release(inode, file);
 }
 
 static const struct file_operations ftrace_pid_fops = {
     .open       = ftrace_pid_open,
     .write      = ftrace_pid_write,
     .read       = seq_read,
     .llseek     = tracing_lseek,
     .release    = ftrace_pid_release,
 };
 
 static const struct file_operations ftrace_no_pid_fops = {
     .open       = ftrace_no_pid_open,
     .write      = ftrace_no_pid_write,
     .read       = seq_read,
     .llseek     = tracing_lseek,
     .release    = ftrace_pid_release,
 };
 
 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 {
     trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
                 tr, &ftrace_pid_fops);
     trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
               d_tracer, tr, &ftrace_no_pid_fops);
 }
 
 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
                      struct dentry *d_tracer)
 {
     /* Only the top level directory has the dyn_tracefs and profile */
     WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
 
     ftrace_init_dyn_tracefs(d_tracer);
     ftrace_profile_tracefs(d_tracer);
 }
 
 /**
  * ftrace_kill - kill ftrace
  *
  * This function should be used by panic code. It stops ftrace
  * but in a not so nice way. If you need to simply kill ftrace
  * from a non-atomic section, use ftrace_kill.
  */
 void ftrace_kill(void)
 {
     ftrace_disabled = 1;
     ftrace_enabled = 0;
     ftrace_trace_function = ftrace_stub;
 }
 
 /**
  * ftrace_is_dead - Test if ftrace is dead or not.
  *
  * Returns 1 if ftrace is "dead", zero otherwise.
  */
 int ftrace_is_dead(void)
 {
     return ftrace_disabled;
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 /*
  * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
  * it doesn't conflict with any direct ftrace_ops. If there is existing
  * direct ftrace_ops on a kernel function being patched, call
  * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
  *
  * @ops:     ftrace_ops being registered.
  *
  * Returns:
  *         0 on success;
  *         Negative on failure.
  */
 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_hash *hash;
     struct ftrace_ops *op;
     int size, i, ret;
 
     lockdep_assert_held_once(&direct_mutex);
 
     if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
         return 0;
 
     hash = ops->func_hash->filter_hash;
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             unsigned long ip = entry->ip;
             bool found_op = false;
 
             mutex_lock(&ftrace_lock);
             do_for_each_ftrace_op(op, ftrace_ops_list) {
                 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
                     continue;
                 if (ops_references_ip(op, ip)) {
                     found_op = true;
                     break;
                 }
             } while_for_each_ftrace_op(op);
             mutex_unlock(&ftrace_lock);
 
             if (found_op) {
                 if (!op->ops_func)
                     return -EBUSY;
 
                 ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
                 if (ret)
                     return ret;
             }
         }
     }
 
     return 0;
 }
 
 /*
  * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
  * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
  * ops.
  */
 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
 {
     struct ftrace_func_entry *entry;
     struct ftrace_hash *hash;
     struct ftrace_ops *op;
     int size, i;
 
     if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
         return;
 
     mutex_lock(&direct_mutex);
 
     hash = ops->func_hash->filter_hash;
     size = 1 << hash->size_bits;
     for (i = 0; i < size; i++) {
         hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
             unsigned long ip = entry->ip;
             bool found_op = false;
 
             mutex_lock(&ftrace_lock);
             do_for_each_ftrace_op(op, ftrace_ops_list) {
                 if (!(op->flags & FTRACE_OPS_FL_DIRECT))
                     continue;
                 if (ops_references_ip(op, ip)) {
                     found_op = true;
                     break;
                 }
             } while_for_each_ftrace_op(op);
             mutex_unlock(&ftrace_lock);
 
             /* The cleanup is optional, ignore any errors */
             if (found_op && op->ops_func)
                 op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
         }
     }
     mutex_unlock(&direct_mutex);
 }
 
 #define lock_direct_mutex() mutex_lock(&direct_mutex)
 #define unlock_direct_mutex()   mutex_unlock(&direct_mutex)
 
 #else  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
 {
     return 0;
 }
 
 static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
 {
 }
 
 #define lock_direct_mutex() do { } while (0)
 #define unlock_direct_mutex()   do { } while (0)
 
 #endif  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 /*
  * Similar to register_ftrace_function, except we don't lock direct_mutex.
  */
 static int register_ftrace_function_nolock(struct ftrace_ops *ops)
 {
     int ret;
 
     ftrace_ops_init(ops);
 
     mutex_lock(&ftrace_lock);
 
     ret = ftrace_startup(ops, 0);
 
     mutex_unlock(&ftrace_lock);
 
     return ret;
 }
 
 /**
  * register_ftrace_function - register a function for profiling
  * @ops:    ops structure that holds the function for profiling.
  *
  * Register a function to be called by all functions in the
  * kernel.
  *
  * Note: @ops->func and all the functions it calls must be labeled
  *       with "notrace", otherwise it will go into a
  *       recursive loop.
  */
 int register_ftrace_function(struct ftrace_ops *ops)
 {
     int ret;
 
     lock_direct_mutex();
     ret = prepare_direct_functions_for_ipmodify(ops);
     if (ret < 0)
         goto out_unlock;
 
     ret = register_ftrace_function_nolock(ops);
 
 out_unlock:
     unlock_direct_mutex();
     return ret;
 }
 EXPORT_SYMBOL_GPL(register_ftrace_function);
 
 /**
  * unregister_ftrace_function - unregister a function for profiling.
  * @ops:    ops structure that holds the function to unregister
  *
  * Unregister a function that was added to be called by ftrace profiling.
  */
 int unregister_ftrace_function(struct ftrace_ops *ops)
 {
     int ret;
 
     mutex_lock(&ftrace_lock);
     ret = ftrace_shutdown(ops, 0);
     mutex_unlock(&ftrace_lock);
 
     cleanup_direct_functions_after_ipmodify(ops);
     return ret;
 }
 EXPORT_SYMBOL_GPL(unregister_ftrace_function);
 
 static int symbols_cmp(const void *a, const void *b)
 {
     const char **str_a = (const char **) a;
     const char **str_b = (const char **) b;
 
     return strcmp(*str_a, *str_b);
 }
 
 struct kallsyms_data {
     unsigned long *addrs;
     const char **syms;
     size_t cnt;
     size_t found;
 };
 
 static int kallsyms_callback(void *data, const char *name,
                  struct module *mod, unsigned long addr)
 {
     struct kallsyms_data *args = data;
     const char **sym;
     int idx;
 
     sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
     if (!sym)
         return 0;
 
     idx = sym - args->syms;
     if (args->addrs[idx])
         return 0;
 
     addr = ftrace_location(addr);
     if (!addr)
         return 0;
 
     args->addrs[idx] = addr;
     args->found++;
     return args->found == args->cnt ? 1 : 0;
 }
 
 /**
  * ftrace_lookup_symbols - Lookup addresses for array of symbols
  *
  * @sorted_syms: array of symbols pointers symbols to resolve,
  * must be alphabetically sorted
  * @cnt: number of symbols/addresses in @syms/@addrs arrays
  * @addrs: array for storing resulting addresses
  *
  * This function looks up addresses for array of symbols provided in
  * @syms array (must be alphabetically sorted) and stores them in
  * @addrs array, which needs to be big enough to store at least @cnt
  * addresses.
  *
  * This function returns 0 if all provided symbols are found,
  * -ESRCH otherwise.
  */
 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
 {
     struct kallsyms_data args;
     int err;
 
     memset(addrs, 0, sizeof(*addrs) * cnt);
     args.addrs = addrs;
     args.syms = sorted_syms;
     args.cnt = cnt;
     args.found = 0;
     err = kallsyms_on_each_symbol(kallsyms_callback, &args);
     if (err < 0)
         return err;
     return args.found == args.cnt ? 0 : -ESRCH;
 }
 
 #ifdef CONFIG_SYSCTL
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 static void ftrace_startup_sysctl(void)
 {
     int command;
 
     if (unlikely(ftrace_disabled))
         return;
 
     /* Force update next time */
     saved_ftrace_func = NULL;
     /* ftrace_start_up is true if we want ftrace running */
     if (ftrace_start_up) {
         command = FTRACE_UPDATE_CALLS;
         if (ftrace_graph_active)
             command |= FTRACE_START_FUNC_RET;
         ftrace_startup_enable(command);
     }
 }
 
 static void ftrace_shutdown_sysctl(void)
 {
     int command;
 
     if (unlikely(ftrace_disabled))
         return;
 
     /* ftrace_start_up is true if ftrace is running */
     if (ftrace_start_up) {
         command = FTRACE_DISABLE_CALLS;
         if (ftrace_graph_active)
             command |= FTRACE_STOP_FUNC_RET;
         ftrace_run_update_code(command);
     }
 }
 #else
 # define ftrace_startup_sysctl()       do { } while (0)
 # define ftrace_shutdown_sysctl()      do { } while (0)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 static bool is_permanent_ops_registered(void)
 {
     struct ftrace_ops *op;
 
     do_for_each_ftrace_op(op, ftrace_ops_list) {
         if (op->flags & FTRACE_OPS_FL_PERMANENT)
             return true;
     } while_for_each_ftrace_op(op);
 
     return false;
 }
 
 static int
 ftrace_enable_sysctl(struct ctl_table *table, int write,
              void *buffer, size_t *lenp, loff_t *ppos)
 {
     int ret = -ENODEV;
 
     mutex_lock(&ftrace_lock);
 
     if (unlikely(ftrace_disabled))
         goto out;
 
     ret = proc_dointvec(table, write, buffer, lenp, ppos);
 
     if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
         goto out;
 
     if (ftrace_enabled) {
 
         /* we are starting ftrace again */
         if (rcu_dereference_protected(ftrace_ops_list,
             lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
             update_ftrace_function();
 
         ftrace_startup_sysctl();
 
     } else {
         if (is_permanent_ops_registered()) {
             ftrace_enabled = true;
             ret = -EBUSY;
             goto out;
         }
 
         /* stopping ftrace calls (just send to ftrace_stub) */
         ftrace_trace_function = ftrace_stub;
 
         ftrace_shutdown_sysctl();
     }
 
     last_ftrace_enabled = !!ftrace_enabled;
  out:
     mutex_unlock(&ftrace_lock);
     return ret;
 }
 
 static struct ctl_table ftrace_sysctls[] = {
     {
         .procname       = "ftrace_enabled",
         .data           = &ftrace_enabled,
         .maxlen         = sizeof(int),
         .mode           = 0644,
         .proc_handler   = ftrace_enable_sysctl,
     },
     {}
 };
 
 static int __init ftrace_sysctl_init(void)
 {
     register_sysctl_init("kernel", ftrace_sysctls);
     return 0;
 }
 late_initcall(ftrace_sysctl_init);
 #endif