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04277e02 | 1 | /* Copyright (C) 2005-2019 Free Software Foundation, Inc. |
7756ba9d DH |
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 <stddef.h> | |
20 | #include <asm/sigcontext.h> | |
21 | #include <linux/signal.h> | |
22 | #include <asm-generic/ucontext.h> | |
23 | #include <asm/unistd.h> | |
24 | ||
25 | 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 | unsigned long *tramp = 0; | |
31 | struct ucontext *uc; | |
32 | ||
33 | if (*retaddr == 0) | |
34 | { | |
35 | /* Kernel inserts the tramp between the signal handler frame and the | |
36 | caller frame in signal handling. */ | |
37 | tramp = (unsigned long *) pc; | |
38 | tramp += 2; | |
39 | if ((*tramp == (0x31800000 | __NR_rt_sigreturn)) | |
40 | && (*(tramp+1) == 0xb9cc0008)) | |
41 | { | |
42 | /* Signal handler function argument are: | |
43 | int sig_num, siginfo_t * info, void * ucontext | |
44 | therefore ucontext is the 3rd argument. */ | |
45 | unsigned long ucptr = ((unsigned long) tramp | |
46 | - sizeof (struct ucontext)); | |
47 | uc = (struct ucontext *) ucptr; | |
48 | *pprev_pc = uc->uc_mcontext.regs.pc; | |
49 | /* Need to record the return address since the return address of the | |
50 | function which causes this signal may not be recorded in the | |
51 | stack. */ | |
52 | *pprev_fp = uc->uc_mcontext.regs.r1; | |
53 | *retaddr = uc->uc_mcontext.regs.r15; | |
54 | /* It is a signal handler. */ | |
55 | return 1; | |
56 | } | |
57 | } | |
58 | return 0; | |
59 | } |