gdb-7.11/gdb/arch/arm-linux.c

/* Common target dependent code for GNU/Linux on ARM systems.

   Copyright (C) 1999-2016 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "common-defs.h"
#include "arch/arm.h"
#include "arm-linux.h"

/* Calculate the offset from stack pointer of the pc register on the stack
   in the case of a sigreturn or sigreturn_rt syscall.  */
int
arm_linux_sigreturn_next_pc_offset (unsigned long sp,
				    unsigned long sp_data,
				    unsigned long svc_number,
				    int is_sigreturn)
{
  /* Offset of R0 register.  */
  int r0_offset = 0;
  /* Offset of PC register.  */
  int pc_offset = 0;

  if (is_sigreturn)
    {
      if (sp_data == ARM_NEW_SIGFRAME_MAGIC)
	r0_offset = ARM_UCONTEXT_SIGCONTEXT + ARM_SIGCONTEXT_R0;
      else
	r0_offset = ARM_SIGCONTEXT_R0;
    }
  else
    {
      if (sp_data == sp + ARM_OLD_RT_SIGFRAME_SIGINFO)
	r0_offset = ARM_OLD_RT_SIGFRAME_UCONTEXT;
      else
	r0_offset = ARM_NEW_RT_SIGFRAME_UCONTEXT;

      r0_offset += ARM_UCONTEXT_SIGCONTEXT + ARM_SIGCONTEXT_R0;
    }

  pc_offset = r0_offset + INT_REGISTER_SIZE * ARM_PC_REGNUM;

  return pc_offset;
}