sysdeps/s390/s390-64/backtrace.c

   1 /* Return backtrace of current program state.  64 bit S/390 version.
   2    Copyright (C) 2001 Free Software Foundation, Inc.
   3    Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <execinfo.h>
  22 #include <stddef.h>
  23
  24
  25 /* This is a global variable set at program start time.  It marks the
  26    highest used stack address.  */
  27 extern void *__libc_stack_end;
  28
  29
  30 /* This is the stack layout we see for every non-leaf function.
  31            size                    offset
  32     %r15 ->    +------------------+
  33              8 | back chain       |   0
  34              8 | end of stack     |   8
  35             32 | scratch          |  16
  36             80 | save area r6-r15 |  48
  37             16 | save area f4,f6  | 128
  38             16 | empty            | 144
  39                +------------------+
  40    r14 in the save area holds the return address.
  41 */
  42
  43 struct layout
  44 {
  45   long back_chain;
  46   long end_of_stack;
  47   long scratch[4];
  48   long save_grps[10];
  49   long save_fp[2];
  50   long empty[2];
  51 };
  52
  53 int
  54 __backtrace (array, size)
  55      void **array;
  56      int size;
  57 {
  58   /* We assume that all the code is generated with frame pointers set.  */
  59   struct layout *stack;
  60   int cnt = 0;
  61
  62   asm ("LGR  %0,%%r15" : "=d" (stack) );
  63   /* We skip the call to this function, it makes no sense to record it.  */
  64   stack = (struct layout *) stack->back_chain;
  65   while (cnt < size)
  66     {
  67       if (stack == NULL || (void *) stack > __libc_stack_end)
  68         /* This means the address is out of range.  Note that for the
  69            toplevel we see a frame pointer with value NULL which clearly is
  70            out of range.  */
  71         break;
  72
  73       array[cnt++] = stack->save_grps[8];
  74
  75       stack = (struct layout *) stack->back_chain;
  76     }
  77
  78   return cnt;
  79 }
  80 weak_alias (__backtrace, backtrace)