gdb/i386bsd-tdep.c

   1 /* Target-dependent code for i386 BSD's.
   2    Copyright 2001, 2002 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "arch-utils.h"
  23 #include "frame.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26
  27 #include "i386-tdep.h"
  28
  29 /* Support for signal handlers.  */
  30
  31 /* Return whether PC is in a BSD sigtramp routine.  */
  32
  33 static int
  34 i386bsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
  35 {
  36   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
  37
  38   return (pc >= tdep->sigtramp_start && pc < tdep->sigtramp_end);
  39 }
  40
  41 /* Assuming FRAME is for a BSD sigtramp routine, return the address of
  42    the associated sigcontext structure.  */
  43
  44 static CORE_ADDR
  45 i386bsd_sigcontext_addr (struct frame_info *frame)
  46 {
  47   if (frame->next)
  48     /* If this isn't the top frame, the next frame must be for the
  49        signal handler itself.  A pointer to the sigcontext structure
  50        is passed as the third argument to the signal handler.  */
  51     return read_memory_unsigned_integer (frame->next->frame + 16, 4);
  52
  53   /* This is the top frame.  We'll have to find the address of the
  54      sigcontext structure by looking at the stack pointer.  */
  55   return read_memory_unsigned_integer (read_register (SP_REGNUM) + 8, 4);
  56 }
  57
  58 /* Assuming FRAME is for a BSD sigtramp routine, return the saved
  59    program counter.
  60
  61    Note: This function is used for Solaris 2 too, so don't make it
  62    static.  */
  63
  64 CORE_ADDR
  65 i386bsd_sigtramp_saved_pc (struct frame_info *frame)
  66 {
  67   int sc_pc_offset = gdbarch_tdep (current_gdbarch)->sc_pc_offset;
  68   CORE_ADDR addr;
  69
  70   addr = i386bsd_sigcontext_addr (frame);
  71   return read_memory_unsigned_integer (addr + sc_pc_offset, 4);
  72 }
  73
  74 /* Return the saved program counter for FRAME.  */
  75
  76 static CORE_ADDR
  77 i386bsd_frame_saved_pc (struct frame_info *frame)
  78 {
  79   if (frame->signal_handler_caller)
  80     return i386bsd_sigtramp_saved_pc (frame);
  81
  82   return read_memory_unsigned_integer (frame->frame + 4, 4);
  83 }
  84
  85 /* Return the start address of the sigtramp routine.  */
  86
  87 CORE_ADDR
  88 i386bsd_sigtramp_start (CORE_ADDR pc)
  89 {
  90   return gdbarch_tdep (current_gdbarch)->sigtramp_start;
  91 }
  92
  93 /* Return the end address of the sigtramp routine.  */
  94
  95 CORE_ADDR
  96 i386bsd_sigtramp_end (CORE_ADDR pc)
  97 {
  98   return gdbarch_tdep (current_gdbarch)->sigtramp_end;
  99 }
 100 \f
 101
 102 /* Support for shared libraries.  */
 103
 104 /* Return non-zero if we are in a shared library trampoline code stub.  */
 105
 106 int
 107 i386bsd_aout_in_solib_call_trampoline (CORE_ADDR pc, char *name)
 108 {
 109   return (name && !strcmp (name, "_DYNAMIC"));
 110 }
 111
 112 /* Traditional BSD (4.3 BSD, still used for BSDI and 386BSD).  */
 113
 114 /* From <machine/signal.h>.  */
 115 int i386bsd_sc_pc_offset = 20;
 116
 117 static void
 118 i386bsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 119 {
 120   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 121
 122   set_gdbarch_pc_in_sigtramp (gdbarch, i386bsd_pc_in_sigtramp);
 123
 124   /* Assume SunOS-style shared libraries.  */
 125   set_gdbarch_in_solib_call_trampoline (gdbarch,
 126                                         i386bsd_aout_in_solib_call_trampoline);
 127
 128   tdep->jb_pc_offset = 0;
 129
 130   tdep->sigtramp_saved_pc = i386bsd_sigtramp_saved_pc;
 131   tdep->sigtramp_start = 0xfdbfdfc0;
 132   tdep->sigtramp_end = 0xfdbfe000;
 133   tdep->sc_pc_offset = i386bsd_sc_pc_offset;
 134 }
 135
 136 /* NetBSD 1.0 or later.  */
 137
 138 /* From <machine/signal.h>.  */
 139 int i386nbsd_sc_pc_offset = 44;
 140
 141 static void
 142 i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 143 {
 144   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 145
 146   /* Obviously NetBSD is BSD-based.  */
 147   i386bsd_init_abi (info, gdbarch);
 148
 149   /* NetBSD uses -freg-struct-return by default.  */
 150   tdep->struct_return = reg_struct_return;
 151
 152   /* NetBSD uses a different memory layout.  */
 153   tdep->sigtramp_start = 0xbfbfdf20;
 154   tdep->sigtramp_end = 0xbfbfdff0;
 155
 156   /* NetBSD has a `struct sigcontext' that's different from the
 157      origional 4.3 BSD.  */
 158   tdep->sc_pc_offset = i386nbsd_sc_pc_offset;
 159 }
 160
 161 /* NetBSD ELF.  */
 162 static void
 163 i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 164 {
 165   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 166
 167   /* It's still NetBSD.  */
 168   i386nbsd_init_abi (info, gdbarch);
 169
 170   /* But ELF-based.  */
 171   i386_elf_init_abi (info, gdbarch);
 172
 173   /* NetBSD ELF uses SVR4-style shared libraries.  */
 174   set_gdbarch_in_solib_call_trampoline (gdbarch,
 175                                         generic_in_solib_call_trampoline);
 176
 177   /* NetBSD ELF uses -fpcc-struct-return by default.  */
 178   tdep->struct_return = pcc_struct_return;
 179
 180   /* We support the SSE registers on NetBSD ELF.  */
 181   tdep->num_xmm_regs = I386_NUM_XREGS - 1;
 182   set_gdbarch_num_regs (gdbarch, I386_NUM_GREGS + I386_NUM_FREGS
 183                         + I386_NUM_XREGS);
 184 }
 185
 186 /* FreeBSD 3.0-RELEASE or later.  */
 187
 188 CORE_ADDR i386fbsd_sigtramp_start = 0xbfbfdf20;
 189 CORE_ADDR i386fbsd_sigtramp_end = 0xbfbfdff0;
 190
 191 static void
 192 i386fbsdaout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 193 {
 194   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 195
 196   /* Obviously FreeBSD is BSD-based.  */
 197   i386bsd_init_abi (info, gdbarch);
 198
 199   /* FreeBSD uses -freg-struct-return by default.  */
 200   tdep->struct_return = reg_struct_return;
 201
 202   /* FreeBSD uses a different memory layout.  */
 203   tdep->sigtramp_start = i386fbsd_sigtramp_start;
 204   tdep->sigtramp_end = i386fbsd_sigtramp_end;
 205 }
 206
 207 static void
 208 i386fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 209 {
 210   /* It's almost identical to FreeBSD a.out.  */
 211   i386fbsdaout_init_abi (info, gdbarch);
 212
 213   /* Except that it uses ELF.  */
 214   i386_elf_init_abi (info, gdbarch);
 215
 216   /* FreeBSD ELF uses SVR4-style shared libraries.  */
 217   set_gdbarch_in_solib_call_trampoline (gdbarch,
 218                                         generic_in_solib_call_trampoline);
 219 }
 220
 221 /* FreeBSD 4.0-RELEASE or later.  */
 222
 223 /* From <machine/signal.h>.  */
 224 int i386fbsd4_sc_pc_offset = 76;
 225
 226 static void
 227 i386fbsd4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 228 {
 229   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 230
 231   /* Inherit stuff from older releases.  We assume that FreeBSD
 232      4.0-RELEASE always uses ELF.  */
 233   i386fbsd_init_abi (info, gdbarch);
 234
 235   /* FreeBSD 4.0 introduced a new `struct sigcontext'.  */
 236   tdep->sc_pc_offset = i386fbsd4_sc_pc_offset;
 237 }
 238
 239 \f
 240 static enum gdb_osabi
 241 i386bsd_aout_osabi_sniffer (bfd *abfd)
 242 {
 243   if (strcmp (bfd_get_target (abfd), "a.out-i386-netbsd") == 0)
 244     return GDB_OSABI_NETBSD_AOUT;
 245
 246   if (strcmp (bfd_get_target (abfd), "a.out-i386-freebsd") == 0)
 247     return GDB_OSABI_FREEBSD_AOUT;
 248
 249   return GDB_OSABI_UNKNOWN;
 250 }
 251
 252 \f
 253 /* Provide a prototype to silence -Wmissing-prototypes.  */
 254 void _initialize_i386bsd_tdep (void);
 255
 256 void
 257 _initialize_i386bsd_tdep (void)
 258 {
 259   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_aout_flavour,
 260                                   i386bsd_aout_osabi_sniffer);
 261
 262   gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_NETBSD_AOUT,
 263                           i386nbsd_init_abi);
 264   gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_NETBSD_ELF,
 265                           i386nbsdelf_init_abi);
 266   gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_FREEBSD_AOUT,
 267                           i386fbsdaout_init_abi);
 268   gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_FREEBSD_ELF,
 269                           i386fbsd4_init_abi);
 270 }