gdb/amd64obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/amd64.
   2
   3    Copyright 2003, 2004 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 2 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, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "frame.h"
  24 #include "gdbcore.h"
  25 #include "osabi.h"
  26 #include "target.h"
  27
  28 #include "gdb_assert.h"
  29 #include "gdb_string.h"
  30
  31 #include "x86-64-tdep.h"
  32
  33 /* Support for signal handlers.  */
  34
  35 static const int amd64obsd_page_size = 4096;
  36
  37 static int
  38 amd64obsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
  39 {
  40   CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
  41   const char sigreturn[] =
  42   {
  43     0x48, 0xc7, 0xc0,
  44     0x67, 0x00, 0x00, 0x00,     /* movq $SYS_sigreturn, %rax */
  45     0x0f, 0x05                  /* syscall */
  46   };
  47   char *buf;
  48
  49   if (name)
  50     return 0;
  51
  52   /* If we can't read the instructions at START_PC, return zero.  */
  53   buf = alloca (sizeof sigreturn);
  54   if (target_read_memory (start_pc + 0x7, buf, sizeof sigreturn))
  55     return 0;
  56
  57   /* Check for sigreturn(2).  */
  58   if (memcmp (buf, sigreturn, sizeof sigreturn))
  59     return 0;
  60
  61   return 1;
  62 }
  63
  64 /* Assuming NEXT_FRAME is for a frame following a BSD sigtramp
  65    routine, return the address of the associated sigcontext structure.  */
  66
  67 static CORE_ADDR
  68 amd64obsd_sigcontext_addr (struct frame_info *next_frame)
  69 {
  70   /* The %rsp register points at `struct sigcontext' upon entry of a
  71      signal trampoline.  */
  72   return frame_unwind_register_unsigned (next_frame, X86_64_RSP_REGNUM);
  73 }
  74 \f
  75 /* OpenBSD 3.5 or later.  */
  76
  77 /* Mapping between the general-purpose registers in `struct reg'
  78    format and GDB's register cache layout.  */
  79
  80 /* From <machine/reg.h>.  Used for ptrace(2), but not for core dumps.  */
  81 int amd64obsd_r_reg_offset[] =
  82 {
  83   14 * 8,                       /* %rax */
  84   13 * 8,                       /* %rbx */
  85   3 * 8,                        /* %rcx */
  86   2 * 8,                        /* %rdx */
  87   1 * 8,                        /* %rsi */
  88   0 * 8,                        /* %rdi */
  89   12 * 8,                       /* %rbp */
  90   15 * 8,                       /* %rsp */
  91   4 * 8,                        /* %r8 .. */
  92   5 * 8,
  93   6 * 8,
  94   7 * 8,
  95   8 * 8,
  96   9 * 8,
  97   10 * 8,
  98   11 * 8,                       /* ... %r15 */
  99   16 * 8,                       /* %rip */
 100   17 * 8,                       /* %eflags */
 101   18 * 8,                       /* %cs */
 102   19 * 8,                       /* %ss */
 103   20 * 8,                       /* %ds */
 104   21 * 8,                       /* %es */
 105   22 * 8,                       /* %fs */
 106   23 * 8                        /* %gs */
 107 };
 108
 109 /* From <machine/signal.h>.  Also used for core dumps.  */
 110 static int amd64obsd_sc_reg_offset[] =
 111 {
 112   14 * 8,                       /* %rax */
 113   13 * 8,                       /* %rbx */
 114   3 * 8,                        /* %rcx */
 115   2 * 8,                        /* %rdx */
 116   1 * 8,                        /* %rsi */
 117   0 * 8,                        /* %rdi */
 118   12 * 8,                       /* %rbp */
 119   24 * 8,                       /* %rsp */
 120   4 * 8,                        /* %r8 ... */
 121   5 * 8,
 122   6 * 8,
 123   7 * 8,
 124   8 * 8,
 125   9 * 8,
 126   10 * 8,
 127   11 * 8,                       /* ... %r15 */
 128   21 * 8,                       /* %rip */
 129   23 * 8,                       /* %eflags */
 130   22 * 8,                       /* %cs */
 131   25 * 8,                       /* %ss */
 132   18 * 8,                       /* %ds */
 133   17 * 8,                       /* %es */
 134   16 * 8,                       /* %fs */
 135   15 * 8                        /* %gs */
 136 };
 137
 138 static void
 139 amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 140 {
 141   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 142
 143   /* Initialize general-purpose register set details first.  */
 144   tdep->gregset_reg_offset = amd64obsd_sc_reg_offset;
 145   tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);
 146   tdep->sizeof_gregset = 26 * 8;
 147
 148   x86_64_init_abi (info, gdbarch);
 149
 150   tdep->jb_pc_offset = 7 * 8;
 151
 152   set_gdbarch_pc_in_sigtramp (gdbarch, amd64obsd_pc_in_sigtramp);
 153   tdep->sigcontext_addr = amd64obsd_sigcontext_addr;
 154   tdep->sc_reg_offset = amd64obsd_sc_reg_offset;
 155   tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);
 156 }
 157 \f
 158
 159 /* Provide a prototype to silence -Wmissing-prototypes.  */
 160 void _initialize_amd64obsd_tdep (void);
 161
 162 void
 163 _initialize_amd64obsd_ndep (void)
 164 {
 165   /* The OpenBSD/amd64 native dependent code makes this assumption.  */
 166   gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == X86_64_NUM_GREGS);
 167
 168   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
 169                           GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi);
 170 }