gdb/arch/arm-linux.h

   1 /* Common target dependent code for GNU/Linux on ARM systems.
   2
   3    Copyright (C) 1999-2015 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef ARM_LINUX_H
  21 #define ARM_LINUX_H
  22
  23 /* There are a couple of different possible stack layouts that
  24    we need to support.
  25
  26    Before version 2.6.18, the kernel used completely independent
  27    layouts for non-RT and RT signals.  For non-RT signals the stack
  28    began directly with a struct sigcontext.  For RT signals the stack
  29    began with two redundant pointers (to the siginfo and ucontext),
  30    and then the siginfo and ucontext.
  31
  32    As of version 2.6.18, the non-RT signal frame layout starts with
  33    a ucontext and the RT signal frame starts with a siginfo and then
  34    a ucontext.  Also, the ucontext now has a designated save area
  35    for coprocessor registers.
  36
  37    For RT signals, it's easy to tell the difference: we look for
  38    pinfo, the pointer to the siginfo.  If it has the expected
  39    value, we have an old layout.  If it doesn't, we have the new
  40    layout.
  41
  42    For non-RT signals, it's a bit harder.  We need something in one
  43    layout or the other with a recognizable offset and value.  We can't
  44    use the return trampoline, because ARM usually uses SA_RESTORER,
  45    in which case the stack return trampoline is not filled in.
  46    We can't use the saved stack pointer, because sigaltstack might
  47    be in use.  So for now we guess the new layout...  */
  48
  49 /* There are three words (trap_no, error_code, oldmask) in
  50    struct sigcontext before r0.  */
  51 #define ARM_SIGCONTEXT_R0 0xc
  52
  53 /* There are five words (uc_flags, uc_link, and three for uc_stack)
  54    in the ucontext_t before the sigcontext.  */
  55 #define ARM_UCONTEXT_SIGCONTEXT 0x14
  56
  57 /* There are three elements in an rt_sigframe before the ucontext:
  58    pinfo, puc, and info.  The first two are pointers and the third
  59    is a struct siginfo, with size 128 bytes.  We could follow puc
  60    to the ucontext, but it's simpler to skip the whole thing.  */
  61 #define ARM_OLD_RT_SIGFRAME_SIGINFO 0x8
  62 #define ARM_OLD_RT_SIGFRAME_UCONTEXT 0x88
  63
  64 #define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80
  65
  66 #define ARM_NEW_SIGFRAME_MAGIC 0x5ac3c35a
  67
  68 int
  69 arm_linux_sigreturn_next_pc_offset (unsigned long sp,
  70                                     unsigned long sp_data,
  71                                     unsigned long svc_number,
  72                                     int is_sigreturn);
  73
  74 #endif /* ARM_LINUX_H */