/* libunwind - a platform-independent unwind library
   Copyright (C) 2008 CodeSourcery
   Copyright 2011 Linaro Limited

This file is part of libunwind.

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */

#include <stdio.h>
#include "unwind_i.h"

#define __linux__
#ifdef __linux__
#define ARM_NR_sigreturn 119
#define ARM_NR_rt_sigreturn 173
#define ARM_NR_OABI_SYSCALL_BASE 0x900000

/* ARM EABI sigreturn (the syscall number is loaded into r7) */
#define MOV_R7_SIGRETURN (0xe3a07000UL | ARM_NR_sigreturn)
#define MOV_R7_RT_SIGRETURN (0xe3a07000UL | ARM_NR_rt_sigreturn)

/* ARM OABI sigreturn (using SWI) */
#define ARM_SIGRETURN \
  (0xef000000UL | ARM_NR_sigreturn | ARM_NR_OABI_SYSCALL_BASE)
#define ARM_RT_SIGRETURN \
  (0xef000000UL | ARM_NR_rt_sigreturn | ARM_NR_OABI_SYSCALL_BASE)

/* Thumb sigreturn (two insns, syscall number is loaded into r7) */
#define THUMB_SIGRETURN (0xdf00UL << 16 | 0x2700 | ARM_NR_sigreturn)
#define THUMB_RT_SIGRETURN (0xdf00UL << 16 | 0x2700 | ARM_NR_rt_sigreturn)
#endif /* __linux__ */

/* Returns 1 in case of a non-RT signal frame and 2 in case of a RT signal
   frame. */
PROTECTED int
unw_is_signal_frame (unw_cursor_t *cursor)
{
#ifdef __linux__
  struct cursor *c = (struct cursor *) cursor;
  unw_word_t w0, ip;
  unw_addr_space_t as;
  unw_accessors_t *a;
  void *arg;
  int ret;

  as = c->dwarf.as;
  a = unw_get_accessors (as);
  arg = c->dwarf.as_arg;

  ip = c->dwarf.ip;

  if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0)
    return ret;

  /* Return 1 if the IP points to a non-RT sigreturn sequence.  */
  if (w0 == MOV_R7_SIGRETURN || w0 == ARM_SIGRETURN || w0 == THUMB_SIGRETURN)
    return 1;
  /* Return 2 if the IP points to a RT sigreturn sequence.  */
  else if (w0 == MOV_R7_RT_SIGRETURN || w0 == ARM_RT_SIGRETURN
           || w0 == THUMB_RT_SIGRETURN)
    return 2;

  return 0;
#else
  printf ("%s: implement me\n", __FUNCTION__);
  return -UNW_ENOINFO;
#endif
}
