gdb/arch/arm-linux.h

   1 /* Common target dependent code for GNU/Linux on ARM systems.
   2
   3    Copyright (C) 1999-2021 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 ARCH_ARM_LINUX_H
  21 #define ARCH_ARM_LINUX_H
  22
  23 /* The index to access CSPR in user_regs defined in GLIBC.  */
  24 #define ARM_CPSR_GREGNUM 16
  25
  26 /* There are a couple of different possible stack layouts that
  27    we need to support.
  28
  29    Before version 2.6.18, the kernel used completely independent
  30    layouts for non-RT and RT signals.  For non-RT signals the stack
  31    began directly with a struct sigcontext.  For RT signals the stack
  32    began with two redundant pointers (to the siginfo and ucontext),
  33    and then the siginfo and ucontext.
  34
  35    As of version 2.6.18, the non-RT signal frame layout starts with
  36    a ucontext and the RT signal frame starts with a siginfo and then
  37    a ucontext.  Also, the ucontext now has a designated save area
  38    for coprocessor registers.
  39
  40    For RT signals, it's easy to tell the difference: we look for
  41    pinfo, the pointer to the siginfo.  If it has the expected
  42    value, we have an old layout.  If it doesn't, we have the new
  43    layout.
  44
  45    For non-RT signals, it's a bit harder.  We need something in one
  46    layout or the other with a recognizable offset and value.  We can't
  47    use the return trampoline, because ARM usually uses SA_RESTORER,
  48    in which case the stack return trampoline is not filled in.
  49    We can't use the saved stack pointer, because sigaltstack might
  50    be in use.  So for now we guess the new layout...  */
  51
  52 /* There are three words (trap_no, error_code, oldmask) in
  53    struct sigcontext before r0.  */
  54 #define ARM_SIGCONTEXT_R0 0xc
  55
  56 /* There are five words (uc_flags, uc_link, and three for uc_stack)
  57    in the ucontext_t before the sigcontext.  */
  58 #define ARM_UCONTEXT_SIGCONTEXT 0x14
  59
  60 /* There are three elements in an rt_sigframe before the ucontext:
  61    pinfo, puc, and info.  The first two are pointers and the third
  62    is a struct siginfo, with size 128 bytes.  We could follow puc
  63    to the ucontext, but it's simpler to skip the whole thing.  */
  64 #define ARM_OLD_RT_SIGFRAME_SIGINFO 0x8
  65 #define ARM_OLD_RT_SIGFRAME_UCONTEXT 0x88
  66
  67 #define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80
  68
  69 #define ARM_NEW_SIGFRAME_MAGIC 0x5ac3c35a
  70
  71 int
  72 arm_linux_sigreturn_next_pc_offset (unsigned long sp,
  73                                     unsigned long sp_data,
  74                                     unsigned long svc_number,
  75                                     int is_sigreturn);
  76
  77 struct arm_get_next_pcs;
  78
  79 CORE_ADDR arm_linux_get_next_pcs_fixup (struct arm_get_next_pcs *self,
  80                                         CORE_ADDR pc);
  81
  82 #endif /* ARCH_ARM_LINUX_H */