| xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame^] | 1 | /* Copyright (C) 2005-2016 Free Software Foundation, Inc. |
| 2 | |
| 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 Lesser General Public License as |
| 7 | published by the Free Software Foundation; either version 2.1 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 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include <stdio.h> |
| 20 | #include <string.h> |
| 21 | #include <sysdep.h> |
| 22 | #include <signal.h> |
| 23 | #include <execinfo.h> |
| 24 | |
| 25 | extern int |
| 26 | _identify_sighandler (unsigned long fp, unsigned long pc, |
| 27 | unsigned long *pprev_fp, unsigned long *pprev_pc, |
| 28 | unsigned long *retaddr); |
| 29 | |
| 30 | inline long |
| 31 | get_frame_size (unsigned long instr) |
| 32 | { |
| 33 | return abs ((short signed) (instr & 0xFFFF)); |
| 34 | } |
| 35 | |
| 36 | static unsigned long * |
| 37 | find_frame_creation (unsigned long *pc) |
| 38 | { |
| 39 | int i; |
| 40 | |
| 41 | /* NOTE: Distance to search is arbitrary. |
| 42 | 250 works well for most things, |
| 43 | 750 picks up things like tcp_recvmsg, |
| 44 | 1000 needed for fat_fill_super. */ |
| 45 | for (i = 0; i < 1000; i++, pc--) |
| 46 | { |
| 47 | unsigned long instr; |
| 48 | unsigned long frame_size; |
| 49 | |
| 50 | instr = *pc; |
| 51 | |
| 52 | /* Is the instruction of the form |
| 53 | addik r1, r1, foo ? */ |
| 54 | if ((instr & 0xFFFF0000) != 0x30210000) |
| 55 | continue; |
| 56 | |
| 57 | frame_size = get_frame_size (instr); |
| 58 | |
| 59 | if ((frame_size < 8) || (frame_size & 3)) |
| 60 | return NULL; |
| 61 | |
| 62 | return pc; |
| 63 | } |
| 64 | return NULL; |
| 65 | } |
| 66 | |
| 67 | static int |
| 68 | lookup_prev_stack_frame (unsigned long fp, unsigned long pc, |
| 69 | unsigned long *pprev_fp, unsigned long *pprev_pc, |
| 70 | unsigned long *retaddr) |
| 71 | { |
| 72 | unsigned long *prologue = NULL; |
| 73 | |
| 74 | int is_signalhandler = _identify_sighandler (fp, pc, pprev_fp, |
| 75 | pprev_pc, retaddr); |
| 76 | |
| 77 | if (!is_signalhandler) |
| 78 | { |
| 79 | prologue = find_frame_creation ((unsigned long *) pc); |
| 80 | |
| 81 | if (prologue) |
| 82 | { |
| 83 | long frame_size = get_frame_size (*prologue); |
| 84 | *pprev_fp = fp + frame_size; |
| 85 | if (*retaddr != 0) |
| 86 | *pprev_pc = *retaddr; |
| 87 | else |
| 88 | *pprev_pc = *(unsigned long *) fp; |
| 89 | |
| 90 | *retaddr = 0; |
| 91 | if (!*pprev_pc || (*pprev_pc & 3)) |
| 92 | prologue=0; |
| 93 | } |
| 94 | else |
| 95 | { |
| 96 | *pprev_pc = 0; |
| 97 | *pprev_fp = fp; |
| 98 | *retaddr = 0; |
| 99 | } |
| 100 | } |
| 101 | return (!*pprev_pc || (*pprev_pc & 3)) ? -1 : 0; |
| 102 | } |
| 103 | |
| 104 | int |
| 105 | __backtrace (void **array, int size) |
| 106 | { |
| 107 | unsigned long pc, fp; |
| 108 | unsigned long ppc, pfp; |
| 109 | /* Return address(r15) is required in the signal handler case, since the |
| 110 | return address of the function which causes the signal may not be |
| 111 | recorded in the stack. */ |
| 112 | unsigned long retaddr; |
| 113 | |
| 114 | int count; |
| 115 | int rc = 0; |
| 116 | |
| 117 | if (size <= 0) |
| 118 | return 0; |
| 119 | |
| 120 | __asm__ __volatile__ ("mfs %0, rpc" |
| 121 | : "=r"(pc)); |
| 122 | |
| 123 | __asm__ __volatile__ ("add %0, r1, r0" |
| 124 | : "=r"(fp)); |
| 125 | |
| 126 | array[0] = (void *) pc; |
| 127 | retaddr = 0; |
| 128 | for (count = 1; count < size; count++) |
| 129 | { |
| 130 | rc = lookup_prev_stack_frame (fp, pc, &pfp, &ppc, &retaddr); |
| 131 | |
| 132 | fp = pfp; |
| 133 | pc = ppc; |
| 134 | array[count] = (void *) pc; |
| 135 | if (rc) |
| 136 | return count; |
| 137 | } |
| 138 | return count; |
| 139 | } |
| 140 | |
| 141 | weak_alias (__backtrace, backtrace) |
| 142 | libc_hidden_def (__backtrace) |