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 "regset.h"
  27 #include "target.h"
  28
  29 #include "gdb_assert.h"
  30 #include "gdb_string.h"
  31
  32 #include "x86-64-tdep.h"
  33 #include "i387-tdep.h"
  34
  35 /* Support for core dumps.  */
  36
  37 static void
  38 amd64obsd_supply_regset (const struct regset *regset,
  39                          struct regcache *regcache, int regnum,
  40                          const void *regs, size_t len)
  41 {
  42   const struct gdbarch_tdep *tdep = regset->descr;
  43
  44   gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE);
  45
  46   i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
  47   x86_64_supply_fxsave (regcache, regnum, (char *)regs + tdep->sizeof_gregset);
  48 }
  49
  50 static const struct regset *
  51 amd64obsd_regset_from_core_section (struct gdbarch *gdbarch,
  52                                     const char *sect_name, size_t sect_size)
  53 {
  54   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  55
  56   /* OpenBSD core dumps don't use seperate register sets for the
  57      general-purpose and floating-point registers.  */
  58
  59   if (strcmp (sect_name, ".reg") == 0
  60       && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE)
  61     {
  62       if (tdep->gregset == NULL)
  63         {
  64           tdep->gregset = XMALLOC (struct regset);
  65           tdep->gregset->descr = tdep;
  66           tdep->gregset->supply_regset = amd64obsd_supply_regset;
  67         }
  68       return tdep->gregset;
  69     }
  70
  71   return NULL;
  72 }
  73 \f
  74
  75 /* Support for signal handlers.  */
  76
  77 static const int amd64obsd_page_size = 4096;
  78
  79 static int
  80 amd64obsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
  81 {
  82   CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
  83   const char sigreturn[] =
  84   {
  85     0x48, 0xc7, 0xc0,
  86     0x67, 0x00, 0x00, 0x00,     /* movq $SYS_sigreturn, %rax */
  87     0x0f, 0x05                  /* syscall */
  88   };
  89   char *buf;
  90
  91   if (name)
  92     return 0;
  93
  94   /* If we can't read the instructions at START_PC, return zero.  */
  95   buf = alloca (sizeof sigreturn);
  96   if (target_read_memory (start_pc + 0x7, buf, sizeof sigreturn))
  97     return 0;
  98
  99   /* Check for sigreturn(2).  */
 100   if (memcmp (buf, sigreturn, sizeof sigreturn))
 101     return 0;
 102
 103   return 1;
 104 }
 105
 106 /* Assuming NEXT_FRAME is for a frame following a BSD sigtramp
 107    routine, return the address of the associated sigcontext structure.  */
 108
 109 static CORE_ADDR
 110 amd64obsd_sigcontext_addr (struct frame_info *next_frame)
 111 {
 112   /* The %rsp register points at `struct sigcontext' upon entry of a
 113      signal trampoline.  */
 114   return frame_unwind_register_unsigned (next_frame, X86_64_RSP_REGNUM);
 115 }
 116 \f
 117 /* OpenBSD 3.5 or later.  */
 118
 119 /* Mapping between the general-purpose registers in `struct reg'
 120    format and GDB's register cache layout.  */
 121
 122 /* From <machine/reg.h>.  */
 123 int amd64obsd_r_reg_offset[] =
 124 {
 125   14 * 8,                       /* %rax */
 126   13 * 8,                       /* %rbx */
 127   3 * 8,                        /* %rcx */
 128   2 * 8,                        /* %rdx */
 129   1 * 8,                        /* %rsi */
 130   0 * 8,                        /* %rdi */
 131   12 * 8,                       /* %rbp */
 132   15 * 8,                       /* %rsp */
 133   4 * 8,                        /* %r8 .. */
 134   5 * 8,
 135   6 * 8,
 136   7 * 8,
 137   8 * 8,
 138   9 * 8,
 139   10 * 8,
 140   11 * 8,                       /* ... %r15 */
 141   16 * 8,                       /* %rip */
 142   17 * 8,                       /* %eflags */
 143   18 * 8,                       /* %cs */
 144   19 * 8,                       /* %ss */
 145   20 * 8,                       /* %ds */
 146   21 * 8,                       /* %es */
 147   22 * 8,                       /* %fs */
 148   23 * 8                        /* %gs */
 149 };
 150
 151 /* From <machine/signal.h>.  */
 152 static int amd64obsd_sc_reg_offset[] =
 153 {
 154   14 * 8,                       /* %rax */
 155   13 * 8,                       /* %rbx */
 156   3 * 8,                        /* %rcx */
 157   2 * 8,                        /* %rdx */
 158   1 * 8,                        /* %rsi */
 159   0 * 8,                        /* %rdi */
 160   12 * 8,                       /* %rbp */
 161   24 * 8,                       /* %rsp */
 162   4 * 8,                        /* %r8 ... */
 163   5 * 8,
 164   6 * 8,
 165   7 * 8,
 166   8 * 8,
 167   9 * 8,
 168   10 * 8,
 169   11 * 8,                       /* ... %r15 */
 170   21 * 8,                       /* %rip */
 171   23 * 8,                       /* %eflags */
 172   22 * 8,                       /* %cs */
 173   25 * 8,                       /* %ss */
 174   18 * 8,                       /* %ds */
 175   17 * 8,                       /* %es */
 176   16 * 8,                       /* %fs */
 177   15 * 8                        /* %gs */
 178 };
 179
 180 static void
 181 amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 182 {
 183   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 184
 185   x86_64_init_abi (info, gdbarch);
 186
 187   /* Initialize general-purpose register set details.  */
 188   tdep->gregset_reg_offset = amd64obsd_r_reg_offset;
 189   tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset);
 190   tdep->sizeof_gregset = 24 * 8;
 191
 192   set_gdbarch_regset_from_core_section (gdbarch,
 193                                         amd64obsd_regset_from_core_section);
 194
 195   tdep->jb_pc_offset = 7 * 8;
 196
 197   set_gdbarch_pc_in_sigtramp (gdbarch, amd64obsd_pc_in_sigtramp);
 198   tdep->sigcontext_addr = amd64obsd_sigcontext_addr;
 199   tdep->sc_reg_offset = amd64obsd_sc_reg_offset;
 200   tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);
 201 }
 202 \f
 203
 204 /* Provide a prototype to silence -Wmissing-prototypes.  */
 205 void _initialize_amd64obsd_tdep (void);
 206
 207 void
 208 _initialize_amd64obsd_tdep (void)
 209 {
 210   /* The OpenBSD/amd64 native dependent code makes this assumption.  */
 211   gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == X86_64_NUM_GREGS);
 212
 213   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
 214                           GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi);
 215
 216   /* OpenBSD uses traditional (a.out) NetBSD-style core dumps.  */
 217   gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
 218                           GDB_OSABI_NETBSD_AOUT, amd64obsd_init_abi);
 219 }