gdb/i386nbsd-tdep.c

   1 /* Target-dependent code for NetBSD/i386.
   2
   3    Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, 2003
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "gdbtypes.h"
  25 #include "gdbcore.h"
  26 #include "regcache.h"
  27 #include "arch-utils.h"
  28 #include "osabi.h"
  29
  30 #include "i386-tdep.h"
  31 #include "i387-tdep.h"
  32 #include "nbsd-tdep.h"
  33
  34 #include "solib-svr4.h"
  35
  36 /* Map a GDB register number to an offset in the reg structure.  */
  37 static int regmap[] =
  38 {
  39   ( 0 * 4),             /* %eax */
  40   ( 1 * 4),             /* %ecx */
  41   ( 2 * 4),             /* %edx */
  42   ( 3 * 4),             /* %ebx */
  43   ( 4 * 4),             /* %esp */
  44   ( 5 * 4),             /* %epb */
  45   ( 6 * 4),             /* %esi */
  46   ( 7 * 4),             /* %edi */
  47   ( 8 * 4),             /* %eip */
  48   ( 9 * 4),             /* %eflags */
  49   (10 * 4),             /* %cs */
  50   (11 * 4),             /* %ss */
  51   (12 * 4),             /* %ds */
  52   (13 * 4),             /* %es */
  53   (14 * 4),             /* %fs */
  54   (15 * 4),             /* %gs */
  55 };
  56
  57 #define SIZEOF_STRUCT_REG       (16 * 4)
  58
  59 static void
  60 i386nbsd_supply_reg (char *regs, int regno)
  61 {
  62   int i;
  63
  64   for (i = 0; i <= 15; i++)
  65     if (regno == i || regno == -1)
  66       supply_register (i, regs + regmap[i]);
  67 }
  68
  69 static void
  70 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
  71                       CORE_ADDR ignore)
  72 {
  73   char *regs, *fsave;
  74
  75   /* We get everything from one section.  */
  76   if (which != 0)
  77     return;
  78
  79   if (core_reg_size < (SIZEOF_STRUCT_REG + 108))
  80     {
  81       warning ("Wrong size register set in core file.");
  82       return;
  83     }
  84
  85   regs = core_reg_sect;
  86   fsave = core_reg_sect + SIZEOF_STRUCT_REG;
  87
  88   /* Integer registers.  */
  89   i386nbsd_supply_reg (regs, -1);
  90
  91   /* Floating point registers.  */
  92   i387_supply_fsave (current_regcache, -1, fsave);
  93 }
  94
  95 static void
  96 fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size,
  97                          int which, CORE_ADDR ignore)
  98 {
  99   switch (which)
 100     {
 101     case 0:  /* Integer registers.  */
 102       if (core_reg_size != SIZEOF_STRUCT_REG)
 103         warning ("Wrong size register set in core file.");
 104       else
 105         i386nbsd_supply_reg (core_reg_sect, -1);
 106       break;
 107
 108     case 2:  /* Floating point registers.  */
 109       if (core_reg_size != 108)
 110         warning ("Wrong size FP register set in core file.");
 111       else
 112         i387_supply_fsave (current_regcache, -1, core_reg_sect);
 113       break;
 114
 115     case 3:  /* "Extended" floating point registers.  This is gdb-speak
 116                 for SSE/SSE2. */
 117       if (core_reg_size != 512)
 118         warning ("Wrong size XMM register set in core file.");
 119       else
 120         i387_supply_fxsave (current_regcache, -1, core_reg_sect);
 121       break;
 122
 123     default:
 124       /* Don't know what kind of register request this is; just ignore it.  */
 125       break;
 126     }
 127 }
 128
 129 static struct core_fns i386nbsd_core_fns =
 130 {
 131   bfd_target_unknown_flavour,           /* core_flavour */
 132   default_check_format,                 /* check_format */
 133   default_core_sniffer,                 /* core_sniffer */
 134   fetch_core_registers,                 /* core_read_registers */
 135   NULL                                  /* next */
 136 };
 137
 138 static struct core_fns i386nbsd_elfcore_fns =
 139 {
 140   bfd_target_elf_flavour,               /* core_flavour */
 141   default_check_format,                 /* check_format */
 142   default_core_sniffer,                 /* core_sniffer */
 143   fetch_elfcore_registers,              /* core_read_registers */
 144   NULL                                  /* next */
 145 };
 146
 147 /* Under NetBSD/i386, signal handler invocations can be identified by the
 148    designated code sequence that is used to return from a signal handler.
 149    In particular, the return address of a signal handler points to the
 150    following code sequence:
 151
 152         leal    0x10(%esp), %eax
 153         pushl   %eax
 154         pushl   %eax
 155         movl    $0x127, %eax            # __sigreturn14
 156         int     $0x80
 157
 158    Each instruction has a unique encoding, so we simply attempt to match
 159    the instruction the PC is pointing to with any of the above instructions.
 160    If there is a hit, we know the offset to the start of the designated
 161    sequence and can then check whether we really are executing in the
 162    signal trampoline.  If not, -1 is returned, otherwise the offset from the
 163    start of the return sequence is returned.  */
 164 #define RETCODE_INSN1           0x8d
 165 #define RETCODE_INSN2           0x50
 166 #define RETCODE_INSN3           0x50
 167 #define RETCODE_INSN4           0xb8
 168 #define RETCODE_INSN5           0xcd
 169
 170 #define RETCODE_INSN2_OFF       4
 171 #define RETCODE_INSN3_OFF       5
 172 #define RETCODE_INSN4_OFF       6
 173 #define RETCODE_INSN5_OFF       11
 174
 175 static const unsigned char sigtramp_retcode[] =
 176 {
 177   RETCODE_INSN1, 0x44, 0x24, 0x10,
 178   RETCODE_INSN2,
 179   RETCODE_INSN3,
 180   RETCODE_INSN4, 0x27, 0x01, 0x00, 0x00,
 181   RETCODE_INSN5, 0x80,
 182 };
 183
 184 static LONGEST
 185 i386nbsd_sigtramp_offset (CORE_ADDR pc)
 186 {
 187   unsigned char ret[sizeof(sigtramp_retcode)], insn;
 188   LONGEST off;
 189   int i;
 190
 191   if (read_memory_nobpt (pc, &insn, 1) != 0)
 192     return -1;
 193
 194   switch (insn)
 195     {
 196     case RETCODE_INSN1:
 197       off = 0;
 198       break;
 199
 200     case RETCODE_INSN2:
 201       /* INSN2 and INSN3 are the same.  Read at the location of PC+1
 202          to determine if we're actually looking at INSN2 or INSN3.  */
 203       if (read_memory_nobpt (pc + 1, &insn, 1) != 0)
 204         return -1;
 205
 206       if (insn == RETCODE_INSN3)
 207         off = RETCODE_INSN2_OFF;
 208       else
 209         off = RETCODE_INSN3_OFF;
 210       break;
 211
 212     case RETCODE_INSN4:
 213       off = RETCODE_INSN4_OFF;
 214       break;
 215
 216     case RETCODE_INSN5:
 217       off = RETCODE_INSN5_OFF;
 218       break;
 219
 220     default:
 221       return -1;
 222     }
 223
 224   pc -= off;
 225
 226   if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0)
 227     return -1;
 228
 229   if (memcmp (ret, sigtramp_retcode, sizeof (ret)) == 0)
 230     return off;
 231
 232   return -1;
 233 }
 234
 235 static int
 236 i386nbsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
 237 {
 238   return (nbsd_pc_in_sigtramp (pc, name)
 239           || i386nbsd_sigtramp_offset (pc) >= 0);
 240 }
 241
 242 /* From <machine/signal.h>.  */
 243 int i386nbsd_sc_reg_offset[I386_NUM_GREGS] =
 244 {
 245   10 * 4,                       /* %eax */
 246   9 * 4,                        /* %ecx */
 247   8 * 4,                        /* %edx */
 248   7 * 4,                        /* %ebx */
 249   14 * 4,                       /* %esp */
 250   6 * 4,                        /* %ebp */
 251   5 * 4,                        /* %esi */
 252   4 * 4,                        /* %edi */
 253   11 * 4,                       /* %eip */
 254   13 * 4,                       /* %eflags */
 255   12 * 4,                       /* %cs */
 256   15 * 4,                       /* %ss */
 257   3 * 4,                        /* %ds */
 258   2 * 4,                        /* %es */
 259   1 * 4,                        /* %fs */
 260   0 * 4                         /* %gs */
 261 };
 262
 263 static void
 264 i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 265 {
 266   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 267
 268   /* Obviously NetBSD is BSD-based.  */
 269   i386bsd_init_abi (info, gdbarch);
 270
 271   /* NetBSD has different signal trampoline conventions.  */
 272   set_gdbarch_pc_in_sigtramp (gdbarch, i386nbsd_pc_in_sigtramp);
 273   /* FIXME: kettenis/20020906: We should probably provide
 274      NetBSD-specific versions of these functions if we want to
 275      recognize signal trampolines that live on the stack.  */
 276   set_gdbarch_sigtramp_start (gdbarch, NULL);
 277   set_gdbarch_sigtramp_end (gdbarch, NULL);
 278
 279   /* NetBSD uses -freg-struct-return by default.  */
 280   tdep->struct_return = reg_struct_return;
 281
 282   /* NetBSD has a `struct sigcontext' that's different from the
 283      origional 4.3 BSD.  */
 284   tdep->sc_reg_offset = i386nbsd_sc_reg_offset;
 285   tdep->sc_num_regs = I386_NUM_GREGS;
 286 }
 287
 288 /* NetBSD ELF.  */
 289 static void
 290 i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 291 {
 292   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 293
 294   /* It's still NetBSD.  */
 295   i386nbsd_init_abi (info, gdbarch);
 296
 297   /* But ELF-based.  */
 298   i386_elf_init_abi (info, gdbarch);
 299
 300   /* NetBSD ELF uses SVR4-style shared libraries.  */
 301   set_gdbarch_in_solib_call_trampoline (gdbarch,
 302                                         generic_in_solib_call_trampoline);
 303   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 304                                  nbsd_ilp32_solib_svr4_fetch_link_map_offsets);
 305
 306   /* NetBSD ELF uses -fpcc-struct-return by default.  */
 307   tdep->struct_return = pcc_struct_return;
 308
 309   /* We support the SSE registers on NetBSD ELF.  */
 310   tdep->num_xmm_regs = I386_NUM_XREGS - 1;
 311   set_gdbarch_num_regs (gdbarch, I386_NUM_GREGS + I386_NUM_FREGS
 312                         + I386_NUM_XREGS);
 313 }
 314
 315 void
 316 _initialize_i386nbsd_tdep (void)
 317 {
 318   add_core_fns (&i386nbsd_core_fns);
 319   add_core_fns (&i386nbsd_elfcore_fns);
 320
 321   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_AOUT,
 322                           i386nbsd_init_abi);
 323   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_ELF,
 324                           i386nbsdelf_init_abi);
 325 }