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1/* Copyright (C) 2005-2019 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
25extern int
26_identify_sighandler (unsigned long fp, unsigned long pc,
27 unsigned long *pprev_fp, unsigned long *pprev_pc,
28 unsigned long *retaddr);
29
30static inline long
31get_frame_size (unsigned long instr)
32{
33 return abs ((short signed) (instr & 0xFFFF));
34}
35
36static unsigned long *
37find_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
67static int
68lookup_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
104int
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
141weak_alias (__backtrace, backtrace)
142libc_hidden_def (__backtrace)
143

Warning: That file was not part of the compilation database. It may have many parsing errors.