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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

 /*
  * Kernel Debugger Architecture Independent Support Functions
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  * Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
  * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
  * 03/02/13    added new 2.5 kallsyms <xavier.bru@bull.net>
  */
 
 #include <linux/types.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/kallsyms.h>
 #include <linux/stddef.h>
 #include <linux/vmalloc.h>
 #include <linux/ptrace.h>
 #include <linux/highmem.h>
 #include <linux/hardirq.h>
 #include <linux/delay.h>
 #include <linux/uaccess.h>
 #include <linux/kdb.h>
 #include <linux/slab.h>
 #include <linux/ctype.h>
 #include "kdb_private.h"
 
 /*
  * kdbgetsymval - Return the address of the given symbol.
  *
  * Parameters:
  *  symname Character string containing symbol name
  *      symtab  Structure to receive results
  * Returns:
  *  0   Symbol not found, symtab zero filled
  *  1   Symbol mapped to module/symbol/section, data in symtab
  */
 int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
 {
     kdb_dbg_printf(AR, "symname=%s, symtab=%px\n", symname, symtab);
     memset(symtab, 0, sizeof(*symtab));
     symtab->sym_start = kallsyms_lookup_name(symname);
     if (symtab->sym_start) {
         kdb_dbg_printf(AR, "returns 1, symtab->sym_start=0x%lx\n",
                    symtab->sym_start);
         return 1;
     }
     kdb_dbg_printf(AR, "returns 0\n");
     return 0;
 }
 EXPORT_SYMBOL(kdbgetsymval);
 
 /**
  * kdbnearsym() - Return the name of the symbol with the nearest address
  *                less than @addr.
  * @addr: Address to check for near symbol
  * @symtab: Structure to receive results
  *
  * WARNING: This function may return a pointer to a single statically
  * allocated buffer (namebuf). kdb's unusual calling context (single
  * threaded, all other CPUs halted) provides us sufficient locking for
  * this to be safe. The only constraint imposed by the static buffer is
  * that the caller must consume any previous reply prior to another call
  * to lookup a new symbol.
  *
  * Note that, strictly speaking, some architectures may re-enter the kdb
  * trap if the system turns out to be very badly damaged and this breaks
  * the single-threaded assumption above. In these circumstances successful
  * continuation and exit from the inner trap is unlikely to work and any
  * user attempting this receives a prominent warning before being allowed
  * to progress. In these circumstances we remain memory safe because
  * namebuf[KSYM_NAME_LEN-1] will never change from '\0' although we do
  * tolerate the possibility of garbled symbol display from the outer kdb
  * trap.
  *
  * Return:
  * * 0 - No sections contain this address, symtab zero filled
  * * 1 - Address mapped to module/symbol/section, data in symtab
  */
 int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
 {
     int ret = 0;
     unsigned long symbolsize = 0;
     unsigned long offset = 0;
     static char namebuf[KSYM_NAME_LEN];
 
     kdb_dbg_printf(AR, "addr=0x%lx, symtab=%px\n", addr, symtab);
     memset(symtab, 0, sizeof(*symtab));
 
     if (addr < 4096)
         goto out;
 
     symtab->sym_name = kallsyms_lookup(addr, &symbolsize , &offset,
                 (char **)(&symtab->mod_name), namebuf);
     if (offset > 8*1024*1024) {
         symtab->sym_name = NULL;
         addr = offset = symbolsize = 0;
     }
     symtab->sym_start = addr - offset;
     symtab->sym_end = symtab->sym_start + symbolsize;
     ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0';
 
     if (symtab->mod_name == NULL)
         symtab->mod_name = "kernel";
     kdb_dbg_printf(AR, "returns %d symtab->sym_start=0x%lx, symtab->mod_name=%px, symtab->sym_name=%px (%s)\n",
                ret, symtab->sym_start, symtab->mod_name, symtab->sym_name, symtab->sym_name);
 out:
     return ret;
 }
 
 static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1];
 
 /*
  * kallsyms_symbol_complete
  *
  * Parameters:
  *  prefix_name prefix of a symbol name to lookup
  *  max_len     maximum length that can be returned
  * Returns:
  *  Number of symbols which match the given prefix.
  * Notes:
  *  prefix_name is changed to contain the longest unique prefix that
  *  starts with this prefix (tab completion).
  */
 int kallsyms_symbol_complete(char *prefix_name, int max_len)
 {
     loff_t pos = 0;
     int prefix_len = strlen(prefix_name), prev_len = 0;
     int i, number = 0;
     const char *name;
 
     while ((name = kdb_walk_kallsyms(&pos))) {
         if (strncmp(name, prefix_name, prefix_len) == 0) {
             strscpy(ks_namebuf, name, sizeof(ks_namebuf));
             /* Work out the longest name that matches the prefix */
             if (++number == 1) {
                 prev_len = min_t(int, max_len-1,
                          strlen(ks_namebuf));
                 memcpy(ks_namebuf_prev, ks_namebuf, prev_len);
                 ks_namebuf_prev[prev_len] = '\0';
                 continue;
             }
             for (i = 0; i < prev_len; i++) {
                 if (ks_namebuf[i] != ks_namebuf_prev[i]) {
                     prev_len = i;
                     ks_namebuf_prev[i] = '\0';
                     break;
                 }
             }
         }
     }
     if (prev_len > prefix_len)
         memcpy(prefix_name, ks_namebuf_prev, prev_len+1);
     return number;
 }
 
 /*
  * kallsyms_symbol_next
  *
  * Parameters:
  *  prefix_name prefix of a symbol name to lookup
  *  flag    0 means search from the head, 1 means continue search.
  *  buf_size    maximum length that can be written to prefix_name
  *          buffer
  * Returns:
  *  1 if a symbol matches the given prefix.
  *  0 if no string found
  */
 int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size)
 {
     int prefix_len = strlen(prefix_name);
     static loff_t pos;
     const char *name;
 
     if (!flag)
         pos = 0;
 
     while ((name = kdb_walk_kallsyms(&pos))) {
         if (!strncmp(name, prefix_name, prefix_len))
             return strscpy(prefix_name, name, buf_size);
     }
     return 0;
 }
 
 /*
  * kdb_symbol_print - Standard method for printing a symbol name and offset.
  * Inputs:
  *  addr    Address to be printed.
  *  symtab  Address of symbol data, if NULL this routine does its
  *      own lookup.
  *  punc    Punctuation for string, bit field.
  * Remarks:
  *  The string and its punctuation is only printed if the address
  *  is inside the kernel, except that the value is always printed
  *  when requested.
  */
 void kdb_symbol_print(unsigned long addr, const kdb_symtab_t *symtab_p,
               unsigned int punc)
 {
     kdb_symtab_t symtab, *symtab_p2;
     if (symtab_p) {
         symtab_p2 = (kdb_symtab_t *)symtab_p;
     } else {
         symtab_p2 = &symtab;
         kdbnearsym(addr, symtab_p2);
     }
     if (!(symtab_p2->sym_name || (punc & KDB_SP_VALUE)))
         return;
     if (punc & KDB_SP_SPACEB)
         kdb_printf(" ");
     if (punc & KDB_SP_VALUE)
         kdb_printf(kdb_machreg_fmt0, addr);
     if (symtab_p2->sym_name) {
         if (punc & KDB_SP_VALUE)
             kdb_printf(" ");
         if (punc & KDB_SP_PAREN)
             kdb_printf("(");
         if (strcmp(symtab_p2->mod_name, "kernel"))
             kdb_printf("[%s]", symtab_p2->mod_name);
         kdb_printf("%s", symtab_p2->sym_name);
         if (addr != symtab_p2->sym_start)
             kdb_printf("+0x%lx", addr - symtab_p2->sym_start);
         if (punc & KDB_SP_SYMSIZE)
             kdb_printf("/0x%lx",
                    symtab_p2->sym_end - symtab_p2->sym_start);
         if (punc & KDB_SP_PAREN)
             kdb_printf(")");
     }
     if (punc & KDB_SP_SPACEA)
         kdb_printf(" ");
     if (punc & KDB_SP_NEWLINE)
         kdb_printf("\n");
 }
 
 /*
  * kdb_strdup - kdb equivalent of strdup, for disasm code.
  * Inputs:
  *  str The string to duplicate.
  *  type    Flags to kmalloc for the new string.
  * Returns:
  *  Address of the new string, NULL if storage could not be allocated.
  * Remarks:
  *  This is not in lib/string.c because it uses kmalloc which is not
  *  available when string.o is used in boot loaders.
  */
 char *kdb_strdup(const char *str, gfp_t type)
 {
     int n = strlen(str)+1;
     char *s = kmalloc(n, type);
     if (!s)
         return NULL;
     return strcpy(s, str);
 }
 
 /*
  * kdb_getarea_size - Read an area of data.  The kdb equivalent of
  *  copy_from_user, with kdb messages for invalid addresses.
  * Inputs:
  *  res Pointer to the area to receive the result.
  *  addr    Address of the area to copy.
  *  size    Size of the area.
  * Returns:
  *  0 for success, < 0 for error.
  */
 int kdb_getarea_size(void *res, unsigned long addr, size_t size)
 {
     int ret = copy_from_kernel_nofault((char *)res, (char *)addr, size);
     if (ret) {
         if (!KDB_STATE(SUPPRESS)) {
             kdb_func_printf("Bad address 0x%lx\n", addr);
             KDB_STATE_SET(SUPPRESS);
         }
         ret = KDB_BADADDR;
     } else {
         KDB_STATE_CLEAR(SUPPRESS);
     }
     return ret;
 }
 
 /*
  * kdb_putarea_size - Write an area of data.  The kdb equivalent of
  *  copy_to_user, with kdb messages for invalid addresses.
  * Inputs:
  *  addr    Address of the area to write to.
  *  res Pointer to the area holding the data.
  *  size    Size of the area.
  * Returns:
  *  0 for success, < 0 for error.
  */
 int kdb_putarea_size(unsigned long addr, void *res, size_t size)
 {
     int ret = copy_to_kernel_nofault((char *)addr, (char *)res, size);
     if (ret) {
         if (!KDB_STATE(SUPPRESS)) {
             kdb_func_printf("Bad address 0x%lx\n", addr);
             KDB_STATE_SET(SUPPRESS);
         }
         ret = KDB_BADADDR;
     } else {
         KDB_STATE_CLEAR(SUPPRESS);
     }
     return ret;
 }
 
 /*
  * kdb_getphys - Read data from a physical address. Validate the
  *  address is in range, use kmap_atomic() to get data
  *  similar to kdb_getarea() - but for phys addresses
  * Inputs:
  *  res Pointer to the word to receive the result
  *  addr    Physical address of the area to copy
  *  size    Size of the area
  * Returns:
  *  0 for success, < 0 for error.
  */
 static int kdb_getphys(void *res, unsigned long addr, size_t size)
 {
     unsigned long pfn;
     void *vaddr;
     struct page *page;
 
     pfn = (addr >> PAGE_SHIFT);
     if (!pfn_valid(pfn))
         return 1;
     page = pfn_to_page(pfn);
     vaddr = kmap_atomic(page);
     memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size);
     kunmap_atomic(vaddr);
 
     return 0;
 }
 
 /*
  * kdb_getphysword
  * Inputs:
  *  word    Pointer to the word to receive the result.
  *  addr    Address of the area to copy.
  *  size    Size of the area.
  * Returns:
  *  0 for success, < 0 for error.
  */
 int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
 {
     int diag;
     __u8  w1;
     __u16 w2;
     __u32 w4;
     __u64 w8;
     *word = 0;  /* Default value if addr or size is invalid */
 
     switch (size) {
     case 1:
         diag = kdb_getphys(&w1, addr, sizeof(w1));
         if (!diag)
             *word = w1;
         break;
     case 2:
         diag = kdb_getphys(&w2, addr, sizeof(w2));
         if (!diag)
             *word = w2;
         break;
     case 4:
         diag = kdb_getphys(&w4, addr, sizeof(w4));
         if (!diag)
             *word = w4;
         break;
     case 8:
         if (size <= sizeof(*word)) {
             diag = kdb_getphys(&w8, addr, sizeof(w8));
             if (!diag)
                 *word = w8;
             break;
         }
         fallthrough;
     default:
         diag = KDB_BADWIDTH;
         kdb_func_printf("bad width %zu\n", size);
     }
     return diag;
 }
 
 /*
  * kdb_getword - Read a binary value.  Unlike kdb_getarea, this treats
  *  data as numbers.
  * Inputs:
  *  word    Pointer to the word to receive the result.
  *  addr    Address of the area to copy.
  *  size    Size of the area.
  * Returns:
  *  0 for success, < 0 for error.
  */
 int kdb_getword(unsigned long *word, unsigned long addr, size_t size)
 {
     int diag;
     __u8  w1;
     __u16 w2;
     __u32 w4;
     __u64 w8;
     *word = 0;  /* Default value if addr or size is invalid */
     switch (size) {
     case 1:
         diag = kdb_getarea(w1, addr);
         if (!diag)
             *word = w1;
         break;
     case 2:
         diag = kdb_getarea(w2, addr);
         if (!diag)
             *word = w2;
         break;
     case 4:
         diag = kdb_getarea(w4, addr);
         if (!diag)
             *word = w4;
         break;
     case 8:
         if (size <= sizeof(*word)) {
             diag = kdb_getarea(w8, addr);
             if (!diag)
                 *word = w8;
             break;
         }
         fallthrough;
     default:
         diag = KDB_BADWIDTH;
         kdb_func_printf("bad width %zu\n", size);
     }
     return diag;
 }
 
 /*
  * kdb_putword - Write a binary value.  Unlike kdb_putarea, this
  *  treats data as numbers.
  * Inputs:
  *  addr    Address of the area to write to..
  *  word    The value to set.
  *  size    Size of the area.
  * Returns:
  *  0 for success, < 0 for error.
  */
 int kdb_putword(unsigned long addr, unsigned long word, size_t size)
 {
     int diag;
     __u8  w1;
     __u16 w2;
     __u32 w4;
     __u64 w8;
     switch (size) {
     case 1:
         w1 = word;
         diag = kdb_putarea(addr, w1);
         break;
     case 2:
         w2 = word;
         diag = kdb_putarea(addr, w2);
         break;
     case 4:
         w4 = word;
         diag = kdb_putarea(addr, w4);
         break;
     case 8:
         if (size <= sizeof(word)) {
             w8 = word;
             diag = kdb_putarea(addr, w8);
             break;
         }
         fallthrough;
     default:
         diag = KDB_BADWIDTH;
         kdb_func_printf("bad width %zu\n", size);
     }
     return diag;
 }
 
 
 
 /*
  * kdb_task_state_char - Return the character that represents the task state.
  * Inputs:
  *  p   struct task for the process
  * Returns:
  *  One character to represent the task state.
  */
 char kdb_task_state_char (const struct task_struct *p)
 {
     unsigned long tmp;
     char state;
     int cpu;
 
     if (!p ||
         copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
         return 'E';
 
     state = task_state_to_char((struct task_struct *) p);
 
     if (is_idle_task(p)) {
         /* Idle task.  Is it really idle, apart from the kdb
          * interrupt? */
         cpu = kdb_process_cpu(p);
         if (!kdb_task_has_cpu(p) || kgdb_info[cpu].irq_depth == 1) {
             if (cpu != kdb_initial_cpu)
                 state = '-';    /* idle task */
         }
     } else if (!p->mm && strchr("IMS", state)) {
         state = tolower(state);     /* sleeping system daemon */
     }
     return state;
 }
 
 /*
  * kdb_task_state - Return true if a process has the desired state
  *  given by the mask.
  * Inputs:
  *  p   struct task for the process
  *  mask    set of characters used to select processes; both NULL
  *          and the empty string mean adopt a default filter, which
  *          is to suppress sleeping system daemons and the idle tasks
  * Returns:
  *  True if the process matches at least one criteria defined by the mask.
  */
 bool kdb_task_state(const struct task_struct *p, const char *mask)
 {
     char state = kdb_task_state_char(p);
 
     /* If there is no mask, then we will filter code that runs when the
      * scheduler is idling and any system daemons that are currently
      * sleeping.
      */
     if (!mask || mask[0] == '\0')
         return !strchr("-ims", state);
 
     /* A is a special case that matches all states */
     if (strchr(mask, 'A'))
         return true;
 
     return strchr(mask, state);
 }
 
 /* Maintain a small stack of kdb_flags to allow recursion without disturbing
  * the global kdb state.
  */
 
 static int kdb_flags_stack[4], kdb_flags_index;
 
 void kdb_save_flags(void)
 {
     BUG_ON(kdb_flags_index >= ARRAY_SIZE(kdb_flags_stack));
     kdb_flags_stack[kdb_flags_index++] = kdb_flags;
 }
 
 void kdb_restore_flags(void)
 {
     BUG_ON(kdb_flags_index <= 0);
     kdb_flags = kdb_flags_stack[--kdb_flags_index];
 }

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