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 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Ftrace header.  For implementation details beyond the random comments
  * scattered below, see: Documentation/trace/ftrace-design.rst
  */
 
 #ifndef _LINUX_FTRACE_H
 #define _LINUX_FTRACE_H
 
 #include <linux/trace_recursion.h>
 #include <linux/trace_clock.h>
 #include <linux/jump_label.h>
 #include <linux/kallsyms.h>
 #include <linux/linkage.h>
 #include <linux/bitops.h>
 #include <linux/ptrace.h>
 #include <linux/ktime.h>
 #include <linux/sched.h>
 #include <linux/types.h>
 #include <linux/init.h>
 #include <linux/fs.h>
 
 #include <asm/ftrace.h>
 
 /*
  * If the arch supports passing the variable contents of
  * function_trace_op as the third parameter back from the
  * mcount call, then the arch should define this as 1.
  */
 #ifndef ARCH_SUPPORTS_FTRACE_OPS
 #define ARCH_SUPPORTS_FTRACE_OPS 0
 #endif
 
 #ifdef CONFIG_TRACING
 extern void ftrace_boot_snapshot(void);
 #else
 static inline void ftrace_boot_snapshot(void) { }
 #endif
 
 #ifdef CONFIG_FUNCTION_TRACER
 struct ftrace_ops;
 struct ftrace_regs;
 /*
  * If the arch's mcount caller does not support all of ftrace's
  * features, then it must call an indirect function that
  * does. Or at least does enough to prevent any unwelcome side effects.
  *
  * Also define the function prototype that these architectures use
  * to call the ftrace_ops_list_func().
  */
 #if !ARCH_SUPPORTS_FTRACE_OPS
 # define FTRACE_FORCE_LIST_FUNC 1
 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
 #else
 # define FTRACE_FORCE_LIST_FUNC 0
 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
                    struct ftrace_ops *op, struct ftrace_regs *fregs);
 #endif
 #endif /* CONFIG_FUNCTION_TRACER */
 
 /* Main tracing buffer and events set up */
 #ifdef CONFIG_TRACING
 void trace_init(void);
 void early_trace_init(void);
 #else
 static inline void trace_init(void) { }
 static inline void early_trace_init(void) { }
 #endif
 
 struct module;
 struct ftrace_hash;
 struct ftrace_direct_func;
 
 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
     defined(CONFIG_DYNAMIC_FTRACE)
 const char *
 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
            unsigned long *off, char **modname, char *sym);
 #else
 static inline const char *
 ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
            unsigned long *off, char **modname, char *sym)
 {
     return NULL;
 }
 #endif
 
 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
 int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
                char *type, char *name,
                char *module_name, int *exported);
 #else
 static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
                      char *type, char *name,
                      char *module_name, int *exported)
 {
     return -1;
 }
 #endif
 
 #ifdef CONFIG_FUNCTION_TRACER
 
 extern int ftrace_enabled;
 
 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
 
 struct ftrace_regs {
     struct pt_regs      regs;
 };
 #define arch_ftrace_get_regs(fregs) (&(fregs)->regs)
 
 /*
  * ftrace_instruction_pointer_set() is to be defined by the architecture
  * if to allow setting of the instruction pointer from the ftrace_regs
  * when HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports
  * live kernel patching.
  */
 #define ftrace_instruction_pointer_set(fregs, ip) do { } while (0)
 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */
 
 static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs)
 {
     if (!fregs)
         return NULL;
 
     return arch_ftrace_get_regs(fregs);
 }
 
 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
                   struct ftrace_ops *op, struct ftrace_regs *fregs);
 
 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
 
 /*
  * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are
  * set in the flags member.
  * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and
  * IPMODIFY are a kind of attribute flags which can be set only before
  * registering the ftrace_ops, and can not be modified while registered.
  * Changing those attribute flags after registering ftrace_ops will
  * cause unexpected results.
  *
  * ENABLED - set/unset when ftrace_ops is registered/unregistered
  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  *           allocated ftrace_ops which need special care
  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  *            and passed to the callback. If this flag is set, but the
  *            architecture does not support passing regs
  *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  *            ftrace_ops will fail to register, unless the next flag
  *            is set.
  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
  *            handler can handle an arch that does not save regs
  *            (the handler tests if regs == NULL), then it can set
  *            this flag instead. It will not fail registering the ftrace_ops
  *            but, the regs field will be NULL if the arch does not support
  *            passing regs to the handler.
  *            Note, if this flag is set, the SAVE_REGS flag will automatically
  *            get set upon registering the ftrace_ops, if the arch supports it.
  * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure
  *            that the call back needs recursion protection. If it does
  *            not set this, then the ftrace infrastructure will assume
  *            that the callback can handle recursion on its own.
  * STUB   - The ftrace_ops is just a place holder.
  * INITIALIZED - The ftrace_ops has already been initialized (first use time
  *            register_ftrace_function() is called, it will initialized the ops)
  * DELETED - The ops are being deleted, do not let them be registered again.
  * ADDING  - The ops is in the process of being added.
  * REMOVING - The ops is in the process of being removed.
  * MODIFYING - The ops is in the process of changing its filter functions.
  * ALLOC_TRAMP - A dynamic trampoline was allocated by the core code.
  *            The arch specific code sets this flag when it allocated a
  *            trampoline. This lets the arch know that it can update the
  *            trampoline in case the callback function changes.
  *            The ftrace_ops trampoline can be set by the ftrace users, and
  *            in such cases the arch must not modify it. Only the arch ftrace
  *            core code should set this flag.
  * IPMODIFY - The ops can modify the IP register. This can only be set with
  *            SAVE_REGS. If another ops with this flag set is already registered
  *            for any of the functions that this ops will be registered for, then
  *            this ops will fail to register or set_filter_ip.
  * PID     - Is affected by set_ftrace_pid (allows filtering on those pids)
  * RCU     - Set when the ops can only be called when RCU is watching.
  * TRACE_ARRAY - The ops->private points to a trace_array descriptor.
  * PERMANENT - Set when the ops is permanent and should not be affected by
  *             ftrace_enabled.
  * DIRECT - Used by the direct ftrace_ops helper for direct functions
  *            (internal ftrace only, should not be used by others)
  */
 enum {
     FTRACE_OPS_FL_ENABLED           = BIT(0),
     FTRACE_OPS_FL_DYNAMIC           = BIT(1),
     FTRACE_OPS_FL_SAVE_REGS         = BIT(2),
     FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED    = BIT(3),
     FTRACE_OPS_FL_RECURSION         = BIT(4),
     FTRACE_OPS_FL_STUB          = BIT(5),
     FTRACE_OPS_FL_INITIALIZED       = BIT(6),
     FTRACE_OPS_FL_DELETED           = BIT(7),
     FTRACE_OPS_FL_ADDING            = BIT(8),
     FTRACE_OPS_FL_REMOVING          = BIT(9),
     FTRACE_OPS_FL_MODIFYING         = BIT(10),
     FTRACE_OPS_FL_ALLOC_TRAMP       = BIT(11),
     FTRACE_OPS_FL_IPMODIFY          = BIT(12),
     FTRACE_OPS_FL_PID           = BIT(13),
     FTRACE_OPS_FL_RCU           = BIT(14),
     FTRACE_OPS_FL_TRACE_ARRAY       = BIT(15),
     FTRACE_OPS_FL_PERMANENT                 = BIT(16),
     FTRACE_OPS_FL_DIRECT            = BIT(17),
 };
 
 /*
  * FTRACE_OPS_CMD_* commands allow the ftrace core logic to request changes
  * to a ftrace_ops. Note, the requests may fail.
  *
  * ENABLE_SHARE_IPMODIFY_SELF - enable a DIRECT ops to work on the same
  *                              function as an ops with IPMODIFY. Called
  *                              when the DIRECT ops is being registered.
  *                              This is called with both direct_mutex and
  *                              ftrace_lock are locked.
  *
  * ENABLE_SHARE_IPMODIFY_PEER - enable a DIRECT ops to work on the same
  *                              function as an ops with IPMODIFY. Called
  *                              when the other ops (the one with IPMODIFY)
  *                              is being registered.
  *                              This is called with direct_mutex locked.
  *
  * DISABLE_SHARE_IPMODIFY_PEER - disable a DIRECT ops to work on the same
  *                               function as an ops with IPMODIFY. Called
  *                               when the other ops (the one with IPMODIFY)
  *                               is being unregistered.
  *                               This is called with direct_mutex locked.
  */
 enum ftrace_ops_cmd {
     FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF,
     FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER,
     FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER,
 };
 
 /*
  * For most ftrace_ops_cmd,
  * Returns:
  *        0 - Success.
  *        Negative on failure. The return value is dependent on the
  *        callback.
  */
 typedef int (*ftrace_ops_func_t)(struct ftrace_ops *op, enum ftrace_ops_cmd cmd);
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 /* The hash used to know what functions callbacks trace */
 struct ftrace_ops_hash {
     struct ftrace_hash __rcu    *notrace_hash;
     struct ftrace_hash __rcu    *filter_hash;
     struct mutex            regex_lock;
 };
 
 void ftrace_free_init_mem(void);
 void ftrace_free_mem(struct module *mod, void *start, void *end);
 #else
 static inline void ftrace_free_init_mem(void)
 {
     ftrace_boot_snapshot();
 }
 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
 #endif
 
 /*
  * Note, ftrace_ops can be referenced outside of RCU protection, unless
  * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
  * core data, the unregistering of it will perform a scheduling on all CPUs
  * to make sure that there are no more users. Depending on the load of the
  * system that may take a bit of time.
  *
  * Any private data added must also take care not to be freed and if private
  * data is added to a ftrace_ops that is in core code, the user of the
  * ftrace_ops must perform a schedule_on_each_cpu() before freeing it.
  */
 struct ftrace_ops {
     ftrace_func_t           func;
     struct ftrace_ops __rcu     *next;
     unsigned long           flags;
     void                *private;
     ftrace_func_t           saved_func;
 #ifdef CONFIG_DYNAMIC_FTRACE
     struct ftrace_ops_hash      local_hash;
     struct ftrace_ops_hash      *func_hash;
     struct ftrace_ops_hash      old_hash;
     unsigned long           trampoline;
     unsigned long           trampoline_size;
     struct list_head        list;
     ftrace_ops_func_t       ops_func;
 #endif
 };
 
 extern struct ftrace_ops __rcu *ftrace_ops_list;
 extern struct ftrace_ops ftrace_list_end;
 
 /*
  * Traverse the ftrace_ops_list, invoking all entries.  The reason that we
  * can use rcu_dereference_raw_check() is that elements removed from this list
  * are simply leaked, so there is no need to interact with a grace-period
  * mechanism.  The rcu_dereference_raw_check() calls are needed to handle
  * concurrent insertions into the ftrace_ops_list.
  *
  * Silly Alpha and silly pointer-speculation compiler optimizations!
  */
 #define do_for_each_ftrace_op(op, list)         \
     op = rcu_dereference_raw_check(list);           \
     do
 
 /*
  * Optimized for just a single item in the list (as that is the normal case).
  */
 #define while_for_each_ftrace_op(op)                \
     while (likely(op = rcu_dereference_raw_check((op)->next)) &&    \
            unlikely((op) != &ftrace_list_end))
 
 /*
  * Type of the current tracing.
  */
 enum ftrace_tracing_type_t {
     FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
     FTRACE_TYPE_RETURN, /* Hook the return of the function */
 };
 
 /* Current tracing type, default is FTRACE_TYPE_ENTER */
 extern enum ftrace_tracing_type_t ftrace_tracing_type;
 
 /*
  * The ftrace_ops must be a static and should also
  * be read_mostly.  These functions do modify read_mostly variables
  * so use them sparely. Never free an ftrace_op or modify the
  * next pointer after it has been registered. Even after unregistering
  * it, the next pointer may still be used internally.
  */
 int register_ftrace_function(struct ftrace_ops *ops);
 int unregister_ftrace_function(struct ftrace_ops *ops);
 
 extern void ftrace_stub(unsigned long a0, unsigned long a1,
             struct ftrace_ops *op, struct ftrace_regs *fregs);
 
 
 int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs);
 #else /* !CONFIG_FUNCTION_TRACER */
 /*
  * (un)register_ftrace_function must be a macro since the ops parameter
  * must not be evaluated.
  */
 #define register_ftrace_function(ops) ({ 0; })
 #define unregister_ftrace_function(ops) ({ 0; })
 static inline void ftrace_kill(void) { }
 static inline void ftrace_free_init_mem(void) { }
 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
 static inline int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
 {
     return -EOPNOTSUPP;
 }
 #endif /* CONFIG_FUNCTION_TRACER */
 
 struct ftrace_func_entry {
     struct hlist_node hlist;
     unsigned long ip;
     unsigned long direct; /* for direct lookup only */
 };
 
 struct dyn_ftrace;
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 extern int ftrace_direct_func_count;
 int register_ftrace_direct(unsigned long ip, unsigned long addr);
 int unregister_ftrace_direct(unsigned long ip, unsigned long addr);
 int modify_ftrace_direct(unsigned long ip, unsigned long old_addr, unsigned long new_addr);
 struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr);
 int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
                 struct dyn_ftrace *rec,
                 unsigned long old_addr,
                 unsigned long new_addr);
 unsigned long ftrace_find_rec_direct(unsigned long ip);
 int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
 int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
 int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr);
 int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr);
 
 #else
 struct ftrace_ops;
 # define ftrace_direct_func_count 0
 static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
 {
     return -ENOTSUPP;
 }
 static inline int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
 {
     return -ENOTSUPP;
 }
 static inline int modify_ftrace_direct(unsigned long ip,
                        unsigned long old_addr, unsigned long new_addr)
 {
     return -ENOTSUPP;
 }
 static inline struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
 {
     return NULL;
 }
 static inline int ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
                           struct dyn_ftrace *rec,
                           unsigned long old_addr,
                           unsigned long new_addr)
 {
     return -ENODEV;
 }
 static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
 {
     return 0;
 }
 static inline int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
     return -ENODEV;
 }
 static inline int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
     return -ENODEV;
 }
 static inline int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
 {
     return -ENODEV;
 }
 static inline int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
 {
     return -ENODEV;
 }
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 /*
  * This must be implemented by the architecture.
  * It is the way the ftrace direct_ops helper, when called
  * via ftrace (because there's other callbacks besides the
  * direct call), can inform the architecture's trampoline that this
  * routine has a direct caller, and what the caller is.
  *
  * For example, in x86, it returns the direct caller
  * callback function via the regs->orig_ax parameter.
  * Then in the ftrace trampoline, if this is set, it makes
  * the return from the trampoline jump to the direct caller
  * instead of going back to the function it just traced.
  */
 static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs,
                          unsigned long addr) { }
 #endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
 
 #ifdef CONFIG_STACK_TRACER
 
 extern int stack_tracer_enabled;
 
 int stack_trace_sysctl(struct ctl_table *table, int write, void *buffer,
                size_t *lenp, loff_t *ppos);
 
 /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */
 DECLARE_PER_CPU(int, disable_stack_tracer);
 
 /**
  * stack_tracer_disable - temporarily disable the stack tracer
  *
  * There's a few locations (namely in RCU) where stack tracing
  * cannot be executed. This function is used to disable stack
  * tracing during those critical sections.
  *
  * This function must be called with preemption or interrupts
  * disabled and stack_tracer_enable() must be called shortly after
  * while preemption or interrupts are still disabled.
  */
 static inline void stack_tracer_disable(void)
 {
     /* Preemption or interrupts must be disabled */
     if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
         WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
     this_cpu_inc(disable_stack_tracer);
 }
 
 /**
  * stack_tracer_enable - re-enable the stack tracer
  *
  * After stack_tracer_disable() is called, stack_tracer_enable()
  * must be called shortly afterward.
  */
 static inline void stack_tracer_enable(void)
 {
     if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
         WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
     this_cpu_dec(disable_stack_tracer);
 }
 #else
 static inline void stack_tracer_disable(void) { }
 static inline void stack_tracer_enable(void) { }
 #endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 void ftrace_arch_code_modify_prepare(void);
 void ftrace_arch_code_modify_post_process(void);
 
 enum ftrace_bug_type {
     FTRACE_BUG_UNKNOWN,
     FTRACE_BUG_INIT,
     FTRACE_BUG_NOP,
     FTRACE_BUG_CALL,
     FTRACE_BUG_UPDATE,
 };
 extern enum ftrace_bug_type ftrace_bug_type;
 
 /*
  * Archs can set this to point to a variable that holds the value that was
  * expected at the call site before calling ftrace_bug().
  */
 extern const void *ftrace_expected;
 
 void ftrace_bug(int err, struct dyn_ftrace *rec);
 
 struct seq_file;
 
 extern int ftrace_text_reserved(const void *start, const void *end);
 
 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
 
 bool is_ftrace_trampoline(unsigned long addr);
 
 /*
  * The dyn_ftrace record's flags field is split into two parts.
  * the first part which is '0-FTRACE_REF_MAX' is a counter of
  * the number of callbacks that have registered the function that
  * the dyn_ftrace descriptor represents.
  *
  * The second part is a mask:
  *  ENABLED - the function is being traced
  *  REGS    - the record wants the function to save regs
  *  REGS_EN - the function is set up to save regs.
  *  IPMODIFY - the record allows for the IP address to be changed.
  *  DISABLED - the record is not ready to be touched yet
  *  DIRECT   - there is a direct function to call
  *
  * When a new ftrace_ops is registered and wants a function to save
  * pt_regs, the rec->flags REGS is set. When the function has been
  * set up to save regs, the REG_EN flag is set. Once a function
  * starts saving regs it will do so until all ftrace_ops are removed
  * from tracing that function.
  */
 enum {
     FTRACE_FL_ENABLED   = (1UL << 31),
     FTRACE_FL_REGS      = (1UL << 30),
     FTRACE_FL_REGS_EN   = (1UL << 29),
     FTRACE_FL_TRAMP     = (1UL << 28),
     FTRACE_FL_TRAMP_EN  = (1UL << 27),
     FTRACE_FL_IPMODIFY  = (1UL << 26),
     FTRACE_FL_DISABLED  = (1UL << 25),
     FTRACE_FL_DIRECT    = (1UL << 24),
     FTRACE_FL_DIRECT_EN = (1UL << 23),
 };
 
 #define FTRACE_REF_MAX_SHIFT    23
 #define FTRACE_REF_MAX      ((1UL << FTRACE_REF_MAX_SHIFT) - 1)
 
 #define ftrace_rec_count(rec)   ((rec)->flags & FTRACE_REF_MAX)
 
 struct dyn_ftrace {
     unsigned long       ip; /* address of mcount call-site */
     unsigned long       flags;
     struct dyn_arch_ftrace  arch;
 };
 
 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
              int remove, int reset);
 int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
               unsigned int cnt, int remove, int reset);
 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
                int len, int reset);
 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
             int len, int reset);
 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 void ftrace_free_filter(struct ftrace_ops *ops);
 void ftrace_ops_set_global_filter(struct ftrace_ops *ops);
 
 enum {
     FTRACE_UPDATE_CALLS     = (1 << 0),
     FTRACE_DISABLE_CALLS        = (1 << 1),
     FTRACE_UPDATE_TRACE_FUNC    = (1 << 2),
     FTRACE_START_FUNC_RET       = (1 << 3),
     FTRACE_STOP_FUNC_RET        = (1 << 4),
     FTRACE_MAY_SLEEP        = (1 << 5),
 };
 
 /*
  * The FTRACE_UPDATE_* enum is used to pass information back
  * from the ftrace_update_record() and ftrace_test_record()
  * functions. These are called by the code update routines
  * to find out what is to be done for a given function.
  *
  *  IGNORE           - The function is already what we want it to be
  *  MAKE_CALL        - Start tracing the function
  *  MODIFY_CALL      - Stop saving regs for the function
  *  MAKE_NOP         - Stop tracing the function
  */
 enum {
     FTRACE_UPDATE_IGNORE,
     FTRACE_UPDATE_MAKE_CALL,
     FTRACE_UPDATE_MODIFY_CALL,
     FTRACE_UPDATE_MAKE_NOP,
 };
 
 enum {
     FTRACE_ITER_FILTER  = (1 << 0),
     FTRACE_ITER_NOTRACE = (1 << 1),
     FTRACE_ITER_PRINTALL    = (1 << 2),
     FTRACE_ITER_DO_PROBES   = (1 << 3),
     FTRACE_ITER_PROBE   = (1 << 4),
     FTRACE_ITER_MOD     = (1 << 5),
     FTRACE_ITER_ENABLED = (1 << 6),
 };
 
 void arch_ftrace_update_code(int command);
 void arch_ftrace_update_trampoline(struct ftrace_ops *ops);
 void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec);
 void arch_ftrace_trampoline_free(struct ftrace_ops *ops);
 
 struct ftrace_rec_iter;
 
 struct ftrace_rec_iter *ftrace_rec_iter_start(void);
 struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
 struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
 
 #define for_ftrace_rec_iter(iter)       \
     for (iter = ftrace_rec_iter_start();    \
          iter;              \
          iter = ftrace_rec_iter_next(iter))
 
 
 int ftrace_update_record(struct dyn_ftrace *rec, bool enable);
 int ftrace_test_record(struct dyn_ftrace *rec, bool enable);
 void ftrace_run_stop_machine(int command);
 unsigned long ftrace_location(unsigned long ip);
 unsigned long ftrace_location_range(unsigned long start, unsigned long end);
 unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
 unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
 
 extern ftrace_func_t ftrace_trace_function;
 
 int ftrace_regex_open(struct ftrace_ops *ops, int flag,
           struct inode *inode, struct file *file);
 ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
                 size_t cnt, loff_t *ppos);
 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
                  size_t cnt, loff_t *ppos);
 int ftrace_regex_release(struct inode *inode, struct file *file);
 
 void __init
 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 
 /* defined in arch */
 extern int ftrace_ip_converted(unsigned long ip);
 extern int ftrace_dyn_arch_init(void);
 extern void ftrace_replace_code(int enable);
 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 extern void ftrace_caller(void);
 extern void ftrace_regs_caller(void);
 extern void ftrace_call(void);
 extern void ftrace_regs_call(void);
 extern void mcount_call(void);
 
 void ftrace_modify_all_code(int command);
 
 #ifndef FTRACE_ADDR
 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 #endif
 
 #ifndef FTRACE_GRAPH_ADDR
 #define FTRACE_GRAPH_ADDR ((unsigned long)ftrace_graph_caller)
 #endif
 
 #ifndef FTRACE_REGS_ADDR
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 #else
 # define FTRACE_REGS_ADDR FTRACE_ADDR
 #endif
 #endif
 
 /*
  * If an arch would like functions that are only traced
  * by the function graph tracer to jump directly to its own
  * trampoline, then they can define FTRACE_GRAPH_TRAMP_ADDR
  * to be that address to jump to.
  */
 #ifndef FTRACE_GRAPH_TRAMP_ADDR
 #define FTRACE_GRAPH_TRAMP_ADDR ((unsigned long) 0)
 #endif
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 extern void ftrace_graph_caller(void);
 extern int ftrace_enable_ftrace_graph_caller(void);
 extern int ftrace_disable_ftrace_graph_caller(void);
 #else
 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 #endif
 
 /**
  * ftrace_make_nop - convert code into nop
  * @mod: module structure if called by module load initialization
  * @rec: the call site record (e.g. mcount/fentry)
  * @addr: the address that the call site should be calling
  *
  * This is a very sensitive operation and great care needs
  * to be taken by the arch.  The operation should carefully
  * read the location, check to see if what is read is indeed
  * what we expect it to be, and then on success of the compare,
  * it should write to the location.
  *
  * The code segment at @rec->ip should be a caller to @addr
  *
  * Return must be:
  *  0 on success
  *  -EFAULT on error reading the location
  *  -EINVAL on a failed compare of the contents
  *  -EPERM  on error writing to the location
  * Any other value will be considered a failure.
  */
 extern int ftrace_make_nop(struct module *mod,
                struct dyn_ftrace *rec, unsigned long addr);
 
 /**
  * ftrace_need_init_nop - return whether nop call sites should be initialized
  *
  * Normally the compiler's -mnop-mcount generates suitable nops, so we don't
  * need to call ftrace_init_nop() if the code is built with that flag.
  * Architectures where this is not always the case may define their own
  * condition.
  *
  * Return must be:
  *  0       if ftrace_init_nop() should be called
  *  Nonzero if ftrace_init_nop() should not be called
  */
 
 #ifndef ftrace_need_init_nop
 #define ftrace_need_init_nop() (!__is_defined(CC_USING_NOP_MCOUNT))
 #endif
 
 /**
  * ftrace_init_nop - initialize a nop call site
  * @mod: module structure if called by module load initialization
  * @rec: the call site record (e.g. mcount/fentry)
  *
  * This is a very sensitive operation and great care needs
  * to be taken by the arch.  The operation should carefully
  * read the location, check to see if what is read is indeed
  * what we expect it to be, and then on success of the compare,
  * it should write to the location.
  *
  * The code segment at @rec->ip should contain the contents created by
  * the compiler
  *
  * Return must be:
  *  0 on success
  *  -EFAULT on error reading the location
  *  -EINVAL on a failed compare of the contents
  *  -EPERM  on error writing to the location
  * Any other value will be considered a failure.
  */
 #ifndef ftrace_init_nop
 static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
 {
     return ftrace_make_nop(mod, rec, MCOUNT_ADDR);
 }
 #endif
 
 /**
  * ftrace_make_call - convert a nop call site into a call to addr
  * @rec: the call site record (e.g. mcount/fentry)
  * @addr: the address that the call site should call
  *
  * This is a very sensitive operation and great care needs
  * to be taken by the arch.  The operation should carefully
  * read the location, check to see if what is read is indeed
  * what we expect it to be, and then on success of the compare,
  * it should write to the location.
  *
  * The code segment at @rec->ip should be a nop
  *
  * Return must be:
  *  0 on success
  *  -EFAULT on error reading the location
  *  -EINVAL on a failed compare of the contents
  *  -EPERM  on error writing to the location
  * Any other value will be considered a failure.
  */
 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 /**
  * ftrace_modify_call - convert from one addr to another (no nop)
  * @rec: the call site record (e.g. mcount/fentry)
  * @old_addr: the address expected to be currently called to
  * @addr: the address to change to
  *
  * This is a very sensitive operation and great care needs
  * to be taken by the arch.  The operation should carefully
  * read the location, check to see if what is read is indeed
  * what we expect it to be, and then on success of the compare,
  * it should write to the location.
  *
  * The code segment at @rec->ip should be a caller to @old_addr
  *
  * Return must be:
  *  0 on success
  *  -EFAULT on error reading the location
  *  -EINVAL on a failed compare of the contents
  *  -EPERM  on error writing to the location
  * Any other value will be considered a failure.
  */
 extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
                   unsigned long addr);
 #else
 /* Should never be called */
 static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
                      unsigned long addr)
 {
     return -EINVAL;
 }
 #endif
 
 /* May be defined in arch */
 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 
 extern int skip_trace(unsigned long ip);
 extern void ftrace_module_init(struct module *mod);
 extern void ftrace_module_enable(struct module *mod);
 extern void ftrace_release_mod(struct module *mod);
 
 extern void ftrace_disable_daemon(void);
 extern void ftrace_enable_daemon(void);
 #else /* CONFIG_DYNAMIC_FTRACE */
 static inline int skip_trace(unsigned long ip) { return 0; }
 static inline void ftrace_disable_daemon(void) { }
 static inline void ftrace_enable_daemon(void) { }
 static inline void ftrace_module_init(struct module *mod) { }
 static inline void ftrace_module_enable(struct module *mod) { }
 static inline void ftrace_release_mod(struct module *mod) { }
 static inline int ftrace_text_reserved(const void *start, const void *end)
 {
     return 0;
 }
 static inline unsigned long ftrace_location(unsigned long ip)
 {
     return 0;
 }
 
 /*
  * Again users of functions that have ftrace_ops may not
  * have them defined when ftrace is not enabled, but these
  * functions may still be called. Use a macro instead of inline.
  */
 #define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
 #define ftrace_set_early_filter(ops, buf, enable) do { } while (0)
 #define ftrace_set_filter_ip(ops, ip, remove, reset) ({ -ENODEV; })
 #define ftrace_set_filter_ips(ops, ips, cnt, remove, reset) ({ -ENODEV; })
 #define ftrace_set_filter(ops, buf, len, reset) ({ -ENODEV; })
 #define ftrace_set_notrace(ops, buf, len, reset) ({ -ENODEV; })
 #define ftrace_free_filter(ops) do { } while (0)
 #define ftrace_ops_set_global_filter(ops) do { } while (0)
 
 static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
                 size_t cnt, loff_t *ppos) { return -ENODEV; }
 static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
                  size_t cnt, loff_t *ppos) { return -ENODEV; }
 static inline int
 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 
 static inline bool is_ftrace_trampoline(unsigned long addr)
 {
     return false;
 }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 #ifndef ftrace_graph_func
 #define ftrace_graph_func ftrace_stub
 #define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB
 #else
 #define FTRACE_OPS_GRAPH_STUB 0
 #endif
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 /* totally disable ftrace - can not re-enable after this */
 void ftrace_kill(void);
 
 static inline void tracer_disable(void)
 {
 #ifdef CONFIG_FUNCTION_TRACER
     ftrace_enabled = 0;
 #endif
 }
 
 /*
  * Ftrace disable/restore without lock. Some synchronization mechanism
  * must be used to prevent ftrace_enabled to be changed between
  * disable/restore.
  */
 static inline int __ftrace_enabled_save(void)
 {
 #ifdef CONFIG_FUNCTION_TRACER
     int saved_ftrace_enabled = ftrace_enabled;
     ftrace_enabled = 0;
     return saved_ftrace_enabled;
 #else
     return 0;
 #endif
 }
 
 static inline void __ftrace_enabled_restore(int enabled)
 {
 #ifdef CONFIG_FUNCTION_TRACER
     ftrace_enabled = enabled;
 #endif
 }
 
 /* All archs should have this, but we define it for consistency */
 #ifndef ftrace_return_address0
 # define ftrace_return_address0 __builtin_return_address(0)
 #endif
 
 /* Archs may use other ways for ADDR1 and beyond */
 #ifndef ftrace_return_address
 # ifdef CONFIG_FRAME_POINTER
 #  define ftrace_return_address(n) __builtin_return_address(n)
 # else
 #  define ftrace_return_address(n) 0UL
 # endif
 #endif
 
 #define CALLER_ADDR0 ((unsigned long)ftrace_return_address0)
 #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
 #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
 #define CALLER_ADDR3 ((unsigned long)ftrace_return_address(3))
 #define CALLER_ADDR4 ((unsigned long)ftrace_return_address(4))
 #define CALLER_ADDR5 ((unsigned long)ftrace_return_address(5))
 #define CALLER_ADDR6 ((unsigned long)ftrace_return_address(6))
 
 static inline unsigned long get_lock_parent_ip(void)
 {
     unsigned long addr = CALLER_ADDR0;
 
     if (!in_lock_functions(addr))
         return addr;
     addr = CALLER_ADDR1;
     if (!in_lock_functions(addr))
         return addr;
     return CALLER_ADDR2;
 }
 
 #ifdef CONFIG_TRACE_PREEMPT_TOGGLE
   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 #else
 /*
  * Use defines instead of static inlines because some arches will make code out
  * of the CALLER_ADDR, when we really want these to be a real nop.
  */
 # define trace_preempt_on(a0, a1) do { } while (0)
 # define trace_preempt_off(a0, a1) do { } while (0)
 #endif
 
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 extern void ftrace_init(void);
 #ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
 #define FTRACE_CALLSITE_SECTION "__patchable_function_entries"
 #else
 #define FTRACE_CALLSITE_SECTION "__mcount_loc"
 #endif
 #else
 static inline void ftrace_init(void) { }
 #endif
 
 /*
  * Structure that defines an entry function trace.
  * It's already packed but the attribute "packed" is needed
  * to remove extra padding at the end.
  */
 struct ftrace_graph_ent {
     unsigned long func; /* Current function */
     int depth;
 } __packed;
 
 /*
  * Structure that defines a return function trace.
  * It's already packed but the attribute "packed" is needed
  * to remove extra padding at the end.
  */
 struct ftrace_graph_ret {
     unsigned long func; /* Current function */
     int depth;
     /* Number of functions that overran the depth limit for current task */
     unsigned int overrun;
     unsigned long long calltime;
     unsigned long long rettime;
 } __packed;
 
 /* Type of the callback handlers for tracing function graph*/
 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 
 extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 struct fgraph_ops {
     trace_func_graph_ent_t      entryfunc;
     trace_func_graph_ret_t      retfunc;
 };
 
 /*
  * Stack of return addresses for functions
  * of a thread.
  * Used in struct thread_info
  */
 struct ftrace_ret_stack {
     unsigned long ret;
     unsigned long func;
     unsigned long long calltime;
 #ifdef CONFIG_FUNCTION_PROFILER
     unsigned long long subtime;
 #endif
 #ifdef HAVE_FUNCTION_GRAPH_FP_TEST
     unsigned long fp;
 #endif
 #ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
     unsigned long *retp;
 #endif
 };
 
 /*
  * Primary handler of a function return.
  * It relays on ftrace_return_to_handler.
  * Defined in entry_32/64.S
  */
 extern void return_to_handler(void);
 
 extern int
 function_graph_enter(unsigned long ret, unsigned long func,
              unsigned long frame_pointer, unsigned long *retp);
 
 struct ftrace_ret_stack *
 ftrace_graph_get_ret_stack(struct task_struct *task, int idx);
 
 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
                     unsigned long ret, unsigned long *retp);
 
 /*
  * Sometimes we don't want to trace a function with the function
  * graph tracer but we want them to keep traced by the usual function
  * tracer if the function graph tracer is not configured.
  */
 #define __notrace_funcgraph     notrace
 
 #define FTRACE_RETFUNC_DEPTH 50
 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 
 extern int register_ftrace_graph(struct fgraph_ops *ops);
 extern void unregister_ftrace_graph(struct fgraph_ops *ops);
 
 /**
  * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
  *
  * ftrace_graph_stop() is called when a severe error is detected in
  * the function graph tracing. This function is called by the critical
  * paths of function graph to keep those paths from doing any more harm.
  */
 DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph);
 
 static inline bool ftrace_graph_is_dead(void)
 {
     return static_branch_unlikely(&kill_ftrace_graph);
 }
 
 extern void ftrace_graph_stop(void);
 
 /* The current handlers in use */
 extern trace_func_graph_ret_t ftrace_graph_return;
 extern trace_func_graph_ent_t ftrace_graph_entry;
 
 extern void ftrace_graph_init_task(struct task_struct *t);
 extern void ftrace_graph_exit_task(struct task_struct *t);
 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 
 static inline void pause_graph_tracing(void)
 {
     atomic_inc(&current->tracing_graph_pause);
 }
 
 static inline void unpause_graph_tracing(void)
 {
     atomic_dec(&current->tracing_graph_pause);
 }
 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 
 #define __notrace_funcgraph
 
 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 
 /* Define as macros as fgraph_ops may not be defined */
 #define register_ftrace_graph(ops) ({ -1; })
 #define unregister_ftrace_graph(ops) do { } while (0)
 
 static inline unsigned long
 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
               unsigned long *retp)
 {
     return ret;
 }
 
 static inline void pause_graph_tracing(void) { }
 static inline void unpause_graph_tracing(void) { }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 #ifdef CONFIG_TRACING
 
 /* flags for current->trace */
 enum {
     TSK_TRACE_FL_TRACE_BIT  = 0,
     TSK_TRACE_FL_GRAPH_BIT  = 1,
 };
 enum {
     TSK_TRACE_FL_TRACE  = 1 << TSK_TRACE_FL_TRACE_BIT,
     TSK_TRACE_FL_GRAPH  = 1 << TSK_TRACE_FL_GRAPH_BIT,
 };
 
 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 {
     set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 }
 
 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 {
     clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 }
 
 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 {
     return tsk->trace & TSK_TRACE_FL_TRACE;
 }
 
 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 {
     set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 }
 
 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 {
     clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 }
 
 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 {
     return tsk->trace & TSK_TRACE_FL_GRAPH;
 }
 
 enum ftrace_dump_mode;
 
 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 extern int tracepoint_printk;
 
 extern void disable_trace_on_warning(void);
 extern int __disable_trace_on_warning;
 
 int tracepoint_printk_sysctl(struct ctl_table *table, int write,
                  void *buffer, size_t *lenp, loff_t *ppos);
 
 #else /* CONFIG_TRACING */
 static inline void  disable_trace_on_warning(void) { }
 #endif /* CONFIG_TRACING */
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 
 unsigned long arch_syscall_addr(int nr);
 
 #endif /* CONFIG_FTRACE_SYSCALLS */
 
 #endif /* _LINUX_FTRACE_H */

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