sysdeps/sparc/backtrace.c

   1 /* Return backtrace of current program state.
   2    Copyright (C) 2013-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If
  17    not, see <https://www.gnu.org/licenses/>.  */
  18
  19 #include <execinfo.h>
  20 #include <stddef.h>
  21 #include <sysdep.h>
  22 #include <sys/trap.h>
  23 #include <backtrace.h>
  24 #include <unwind-link.h>
  25
  26 struct layout
  27 {
  28   unsigned long locals[8];
  29   unsigned long ins[6];
  30   unsigned long next;
  31   void *return_address;
  32 };
  33
  34 struct trace_arg
  35 {
  36   void **array;
  37   struct unwind_link *unwind_link;
  38   _Unwind_Word cfa;
  39   int cnt;
  40   int size;
  41 };
  42
  43 static _Unwind_Reason_Code
  44 backtrace_helper (struct _Unwind_Context *ctx, void *a)
  45 {
  46   struct trace_arg *arg = a;
  47   _Unwind_Ptr ip;
  48
  49   /* We are first called with address in the __backtrace function.
  50      Skip it.  */
  51   if (arg->cnt != -1)
  52     {
  53       ip = UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetIP) (ctx);
  54       arg->array[arg->cnt] = (void *) ip;
  55
  56       /* Check whether we make any progress.  */
  57       _Unwind_Word cfa
  58         = UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetCFA) (ctx);
  59
  60       if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt]
  61          && cfa == arg->cfa)
  62        return _URC_END_OF_STACK;
  63       arg->cfa = cfa;
  64     }
  65   if (++arg->cnt == arg->size)
  66     return _URC_END_OF_STACK;
  67   return _URC_NO_REASON;
  68 }
  69
  70 int
  71 __backtrace (void **array, int size)
  72 {
  73   int count;
  74   struct trace_arg arg =
  75     {
  76      .array = array,
  77      .unwind_link = __libc_unwind_link_get (),
  78      .size = size,
  79      .cnt = -1,
  80     };
  81
  82   if (size <= 0)
  83     return 0;
  84
  85   if (arg.unwind_link == NULL)
  86     {
  87       struct layout *current;
  88       unsigned long fp, i7;
  89
  90       asm volatile ("mov %%fp, %0" : "=r"(fp));
  91       asm volatile ("mov %%i7, %0" : "=r"(i7));
  92       current = (struct layout *) (fp + BACKTRACE_STACK_BIAS);
  93
  94       array[0] = (void *) i7;
  95
  96       if (size == 1)
  97         return 1;
  98
  99       backtrace_flush_register_windows();
 100       for (count = 1; count < size; count++)
 101         {
 102           array[count] = current->return_address;
 103           if (!current->next)
 104             break;
 105           current = (struct layout *) (current->next + BACKTRACE_STACK_BIAS);
 106         }
 107     }
 108   else
 109     {
 110       UNWIND_LINK_PTR (arg.unwind_link, _Unwind_Backtrace)
 111         (backtrace_helper, &arg);
 112
 113       /* _Unwind_Backtrace seems to put NULL address above
 114          _start.  Fix it up here.  */
 115       if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
 116         --arg.cnt;
 117       count = arg.cnt != -1 ? arg.cnt : 0;
 118     }
 119   return count;
 120 }
 121 weak_alias (__backtrace, backtrace)
 122 libc_hidden_def (__backtrace)