| 1 | /* Copyright (C) 2005-2022 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 | <https://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 <sys/syscall.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 | } |
|---|
| 60 | |
|---|
