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/* Copyright (C) 2005-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <stddef.h>
#include <asm/sigcontext.h>
#include <linux/signal.h>
#include <asm-generic/ucontext.h>
#include <asm/unistd.h>
int
_identify_sighandler (unsigned long fp, unsigned long pc,
unsigned long *pprev_fp, unsigned long *pprev_pc,
unsigned long *retaddr)
{
unsigned long *tramp = 0;
struct ucontext *uc;
if (*retaddr == 0)
{
/* Kernel inserts the tramp between the signal handler frame and the
caller frame in signal handling. */
tramp = (unsigned long *) pc;
tramp += 2;
if ((*tramp == (0x31800000 | __NR_rt_sigreturn))
&& (*(tramp+1) == 0xb9cc0008))
{
/* Signal handler function argument are:
int sig_num, siginfo_t * info, void * ucontext
therefore ucontext is the 3rd argument. */
unsigned long ucptr = ((unsigned long) tramp
- sizeof (struct ucontext));
uc = (struct ucontext *) ucptr;
*pprev_pc = uc->uc_mcontext.regs.pc;
/* Need to record the return address since the return address of the
function which causes this signal may not be recorded in the
stack. */
*pprev_fp = uc->uc_mcontext.regs.r1;
*retaddr = uc->uc_mcontext.regs.r15;
/* It is a signal handler. */
return 1;
}
}
return 0;
}
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