gdb/i386nbsd-tdep.c

   1 /* Target-dependent code for NetBSD/i386, for GDB.
   2    Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, 2003
   3    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 "gdbtypes.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26 #include "arch-utils.h"
  27 #include "osabi.h"
  28
  29 #include "i386-tdep.h"
  30 #include "i387-tdep.h"
  31 #include "nbsd-tdep.h"
  32
  33 #include "solib-svr4.h"
  34
  35 /* Map a GDB register number to an offset in the reg structure.  */
  36 static int regmap[] =
  37 {
  38   ( 0 * 4),             /* %eax */
  39   ( 1 * 4),             /* %ecx */
  40   ( 2 * 4),             /* %edx */
  41   ( 3 * 4),             /* %ebx */
  42   ( 4 * 4),             /* %esp */
  43   ( 5 * 4),             /* %epb */
  44   ( 6 * 4),             /* %esi */
  45   ( 7 * 4),             /* %edi */
  46   ( 8 * 4),             /* %eip */
  47   ( 9 * 4),             /* %eflags */
  48   (10 * 4),             /* %cs */
  49   (11 * 4),             /* %ss */
  50   (12 * 4),             /* %ds */
  51   (13 * 4),             /* %es */
  52   (14 * 4),             /* %fs */
  53   (15 * 4),             /* %gs */
  54 };
  55
  56 #define SIZEOF_STRUCT_REG       (16 * 4)
  57
  58 static void
  59 i386nbsd_supply_reg (char *regs, int regno)
  60 {
  61   int i;
  62
  63   for (i = 0; i <= 15; i++)
  64     if (regno == i || regno == -1)
  65       supply_register (i, regs + regmap[i]);
  66 }
  67
  68 static void
  69 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
  70                       CORE_ADDR ignore)
  71 {
  72   char *regs, *fsave;
  73
  74   /* We get everything from one section.  */
  75   if (which != 0)
  76     return;
  77
  78   if (core_reg_size < (SIZEOF_STRUCT_REG + 108))
  79     {
  80       warning ("Wrong size register set in core file.");
  81       return;
  82     }
  83
  84   regs = core_reg_sect;
  85   fsave = core_reg_sect + SIZEOF_STRUCT_REG;
  86
  87   /* Integer registers.  */
  88   i386nbsd_supply_reg (regs, -1);
  89
  90   /* Floating point registers.  */
  91   i387_supply_fsave (fsave);
  92 }
  93
  94 static void
  95 fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size,
  96                          int which, CORE_ADDR ignore)
  97 {
  98   switch (which)
  99     {
 100     case 0:  /* Integer registers.  */
 101       if (core_reg_size != SIZEOF_STRUCT_REG)
 102         warning ("Wrong size register set in core file.");
 103       else
 104         i386nbsd_supply_reg (core_reg_sect, -1);
 105       break;
 106
 107     case 2:  /* Floating point registers.  */
 108       if (core_reg_size != 108)
 109         warning ("Wrong size FP register set in core file.");
 110       else
 111         i387_supply_fsave (core_reg_sect);
 112       break;
 113
 114     case 3:  /* "Extended" floating point registers.  This is gdb-speak
 115                 for SSE/SSE2. */
 116       if (core_reg_size != 512)
 117         warning ("Wrong size XMM register set in core file.");
 118       else
 119         i387_supply_fxsave (core_reg_sect);
 120       break;
 121
 122     default:
 123       /* Don't know what kind of register request this is; just ignore it.  */
 124       break;
 125     }
 126 }
 127
 128 static struct core_fns i386nbsd_core_fns =
 129 {
 130   bfd_target_unknown_flavour,           /* core_flavour */
 131   default_check_format,                 /* check_format */
 132   default_core_sniffer,                 /* core_sniffer */
 133   fetch_core_registers,                 /* core_read_registers */
 134   NULL                                  /* next */
 135 };
 136
 137 static struct core_fns i386nbsd_elfcore_fns =
 138 {
 139   bfd_target_elf_flavour,               /* core_flavour */
 140   default_check_format,                 /* check_format */
 141   default_core_sniffer,                 /* core_sniffer */
 142   fetch_elfcore_registers,              /* core_read_registers */
 143   NULL                                  /* next */
 144 };
 145
 146 /* Under NetBSD/i386, signal handler invocations can be identified by the
 147    designated code sequence that is used to return from a signal handler.
 148    In particular, the return address of a signal handler points to the
 149    following code sequence:
 150
 151         leal    0x10(%esp), %eax
 152         pushl   %eax
 153         pushl   %eax
 154         movl    $0x127, %eax            # __sigreturn14
 155         int     $0x80
 156
 157    Each instruction has a unique encoding, so we simply attempt to match
 158    the instruction the PC is pointing to with any of the above instructions.
 159    If there is a hit, we know the offset to the start of the designated
 160    sequence and can then check whether we really are executing in the
 161    signal trampoline.  If not, -1 is returned, otherwise the offset from the
 162    start of the return sequence is returned.  */
 163 #define RETCODE_INSN1           0x8d
 164 #define RETCODE_INSN2           0x50
 165 #define RETCODE_INSN3           0x50
 166 #define RETCODE_INSN4           0xb8
 167 #define RETCODE_INSN5           0xcd
 168
 169 #define RETCODE_INSN2_OFF       4
 170 #define RETCODE_INSN3_OFF       5
 171 #define RETCODE_INSN4_OFF       6
 172 #define RETCODE_INSN5_OFF       11
 173
 174 static const unsigned char sigtramp_retcode[] =
 175 {
 176   RETCODE_INSN1, 0x44, 0x24, 0x10,
 177   RETCODE_INSN2,
 178   RETCODE_INSN3,
 179   RETCODE_INSN4, 0x27, 0x01, 0x00, 0x00,
 180   RETCODE_INSN5, 0x80,
 181 };
 182
 183 static LONGEST
 184 i386nbsd_sigtramp_offset (CORE_ADDR pc)
 185 {
 186   unsigned char ret[sizeof(sigtramp_retcode)], insn;
 187   LONGEST off;
 188   int i;
 189
 190   if (read_memory_nobpt (pc, &insn, 1) != 0)
 191     return -1;
 192
 193   switch (insn)
 194     {
 195     case RETCODE_INSN1:
 196       off = 0;
 197       break;
 198
 199     case RETCODE_INSN2:
 200       /* INSN2 and INSN3 are the same.  Read at the location of PC+1
 201          to determine if we're actually looking at INSN2 or INSN3.  */
 202       if (read_memory_nobpt (pc + 1, &insn, 1) != 0)
 203         return -1;
 204
 205       if (insn == RETCODE_INSN3)
 206         off = RETCODE_INSN2_OFF;
 207       else
 208         off = RETCODE_INSN3_OFF;
 209       break;
 210
 211     case RETCODE_INSN4:
 212       off = RETCODE_INSN4_OFF;
 213       break;
 214
 215     case RETCODE_INSN5:
 216       off = RETCODE_INSN5_OFF;
 217       break;
 218
 219     default:
 220       return -1;
 221     }
 222
 223   pc -= off;
 224
 225   if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0)
 226     return -1;
 227
 228   if (memcmp (ret, sigtramp_retcode, sizeof (ret)) == 0)
 229     return off;
 230
 231   return -1;
 232 }
 233
 234 static int
 235 i386nbsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
 236 {
 237   return (nbsd_pc_in_sigtramp (pc, name)
 238           || i386nbsd_sigtramp_offset (pc) >= 0);
 239 }
 240
 241 /* From <machine/signal.h>.  */
 242 int i386nbsd_sc_pc_offset = 44;
 243 int i386nbsd_sc_sp_offset = 56;
 244
 245 static void
 246 i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 247 {
 248   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 249
 250   /* Obviously NetBSD is BSD-based.  */
 251   i386bsd_init_abi (info, gdbarch);
 252
 253   /* NetBSD has different signal trampoline conventions.  */
 254   set_gdbarch_pc_in_sigtramp (gdbarch, i386nbsd_pc_in_sigtramp);
 255   /* FIXME: kettenis/20020906: We should probably provide
 256      NetBSD-specific versions of these functions if we want to
 257      recognize signal trampolines that live on the stack.  */
 258   set_gdbarch_sigtramp_start (gdbarch, NULL);
 259   set_gdbarch_sigtramp_end (gdbarch, NULL);
 260
 261   /* NetBSD uses -freg-struct-return by default.  */
 262   tdep->struct_return = reg_struct_return;
 263
 264   /* NetBSD has a `struct sigcontext' that's different from the
 265      origional 4.3 BSD.  */
 266   tdep->sc_pc_offset = i386nbsd_sc_pc_offset;
 267   tdep->sc_sp_offset = i386nbsd_sc_sp_offset;
 268 }
 269
 270 /* NetBSD ELF.  */
 271 static void
 272 i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 273 {
 274   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 275
 276   /* It's still NetBSD.  */
 277   i386nbsd_init_abi (info, gdbarch);
 278
 279   /* But ELF-based.  */
 280   i386_elf_init_abi (info, gdbarch);
 281
 282   /* NetBSD ELF uses SVR4-style shared libraries.  */
 283   set_gdbarch_in_solib_call_trampoline (gdbarch,
 284                                         generic_in_solib_call_trampoline);
 285   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 286                                  nbsd_ilp32_solib_svr4_fetch_link_map_offsets);
 287
 288   /* NetBSD ELF uses -fpcc-struct-return by default.  */
 289   tdep->struct_return = pcc_struct_return;
 290
 291   /* We support the SSE registers on NetBSD ELF.  */
 292   tdep->num_xmm_regs = I386_NUM_XREGS - 1;
 293   set_gdbarch_num_regs (gdbarch, I386_NUM_GREGS + I386_NUM_FREGS
 294                         + I386_NUM_XREGS);
 295 }
 296
 297 void
 298 _initialize_i386nbsd_tdep (void)
 299 {
 300   add_core_fns (&i386nbsd_core_fns);
 301   add_core_fns (&i386nbsd_elfcore_fns);
 302
 303   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_AOUT,
 304                           i386nbsd_init_abi);
 305   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_ELF,
 306                           i386nbsdelf_init_abi);
 307 }