/* Copyright (C) 2005-2018 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

   <http://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;

}