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 "gdb_string.h"
  28
  29 #include "i386-tdep.h"
  30
  31 /* Support for signal handlers.  */
  32
  33 /* Return whether PC is in a BSD sigtramp routine.  */
  34
  35 static int
  36 i386bsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
  37 {
  38   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
  39
  40   return (pc >= tdep->sigtramp_start && pc < tdep->sigtramp_end);
  41 }
  42
  43 /* Assuming FRAME is for a BSD sigtramp routine, return the address of
  44    the associated sigcontext structure.
  45
  46    Note: This function is used for Solaris 2 too, so don't make it
  47    static.  */
  48
  49 CORE_ADDR
  50 i386bsd_sigcontext_addr (struct frame_info *frame)
  51 {
  52   if (frame->next)
  53     /* If this isn't the top frame, the next frame must be for the
  54        signal handler itself.  A pointer to the sigcontext structure
  55        is passed as the third argument to the signal handler.  */
  56     return read_memory_unsigned_integer (frame->next->frame + 16, 4);
  57
  58   /* This is the top frame.  We'll have to find the address of the
  59      sigcontext structure by looking at the stack pointer.  */
  60   return read_memory_unsigned_integer (read_register (SP_REGNUM) + 8, 4);
  61 }
  62
  63 /* Return the start address of the sigtramp routine.  */
  64
  65 CORE_ADDR
  66 i386bsd_sigtramp_start (CORE_ADDR pc)
  67 {
  68   return gdbarch_tdep (current_gdbarch)->sigtramp_start;
  69 }
  70
  71 /* Return the end address of the sigtramp routine.  */
  72
  73 CORE_ADDR
  74 i386bsd_sigtramp_end (CORE_ADDR pc)
  75 {
  76   return gdbarch_tdep (current_gdbarch)->sigtramp_end;
  77 }
  78 \f
  79
  80 /* Support for shared libraries.  */
  81
  82 /* Return non-zero if we are in a shared library trampoline code stub.  */
  83
  84 int
  85 i386bsd_aout_in_solib_call_trampoline (CORE_ADDR pc, char *name)
  86 {
  87   return (name && !strcmp (name, "_DYNAMIC"));
  88 }
  89
  90 /* Traditional BSD (4.3 BSD, still used for BSDI and 386BSD).  */
  91
  92 /* From <machine/signal.h>.  */
  93 int i386bsd_sc_pc_offset = 20;
  94 int i386bsd_sc_sp_offset = 8;
  95
  96 void
  97 i386bsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
  98 {
  99   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 100
 101   set_gdbarch_pc_in_sigtramp (gdbarch, i386bsd_pc_in_sigtramp);
 102
 103   /* Allow the recognition of sigtramps as a function named <sigtramp>.  */
 104   set_gdbarch_sigtramp_start (gdbarch, i386bsd_sigtramp_start);
 105   set_gdbarch_sigtramp_end (gdbarch, i386bsd_sigtramp_end);
 106
 107   /* Assume SunOS-style shared libraries.  */
 108   set_gdbarch_in_solib_call_trampoline (gdbarch,
 109                                         i386bsd_aout_in_solib_call_trampoline);
 110
 111   tdep->jb_pc_offset = 0;
 112
 113   tdep->sigtramp_start = 0xfdbfdfc0;
 114   tdep->sigtramp_end = 0xfdbfe000;
 115   tdep->sigcontext_addr = i386bsd_sigcontext_addr;
 116   tdep->sc_pc_offset = i386bsd_sc_pc_offset;
 117   tdep->sc_sp_offset = i386bsd_sc_sp_offset;
 118 }
 119
 120 /* FreeBSD 3.0-RELEASE or later.  */
 121
 122 CORE_ADDR i386fbsd_sigtramp_start = 0xbfbfdf20;
 123 CORE_ADDR i386fbsd_sigtramp_end = 0xbfbfdff0;
 124
 125 static void
 126 i386fbsdaout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 127 {
 128   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 129
 130   /* Obviously FreeBSD is BSD-based.  */
 131   i386bsd_init_abi (info, gdbarch);
 132
 133   /* FreeBSD uses -freg-struct-return by default.  */
 134   tdep->struct_return = reg_struct_return;
 135
 136   /* FreeBSD uses a different memory layout.  */
 137   tdep->sigtramp_start = i386fbsd_sigtramp_start;
 138   tdep->sigtramp_end = i386fbsd_sigtramp_end;
 139 }
 140
 141 static void
 142 i386fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 143 {
 144   /* It's almost identical to FreeBSD a.out.  */
 145   i386fbsdaout_init_abi (info, gdbarch);
 146
 147   /* Except that it uses ELF.  */
 148   i386_elf_init_abi (info, gdbarch);
 149
 150   /* FreeBSD ELF uses SVR4-style shared libraries.  */
 151   set_gdbarch_in_solib_call_trampoline (gdbarch,
 152                                         generic_in_solib_call_trampoline);
 153 }
 154
 155 /* FreeBSD 4.0-RELEASE or later.  */
 156
 157 /* From <machine/signal.h>.  */
 158 int i386fbsd4_sc_pc_offset = 76;
 159 int i386fbsd4_sc_sp_offset = 88;
 160
 161 static void
 162 i386fbsd4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 163 {
 164   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 165
 166   /* Inherit stuff from older releases.  We assume that FreeBSD
 167      4.0-RELEASE always uses ELF.  */
 168   i386fbsd_init_abi (info, gdbarch);
 169
 170   /* FreeBSD 4.0 introduced a new `struct sigcontext'.  */
 171   tdep->sc_pc_offset = i386fbsd4_sc_pc_offset;
 172   tdep->sc_sp_offset = i386fbsd4_sc_sp_offset;
 173 }
 174
 175 \f
 176 static enum gdb_osabi
 177 i386bsd_aout_osabi_sniffer (bfd *abfd)
 178 {
 179   if (strcmp (bfd_get_target (abfd), "a.out-i386-netbsd") == 0)
 180     return GDB_OSABI_NETBSD_AOUT;
 181
 182   if (strcmp (bfd_get_target (abfd), "a.out-i386-freebsd") == 0)
 183     return GDB_OSABI_FREEBSD_AOUT;
 184
 185   return GDB_OSABI_UNKNOWN;
 186 }
 187
 188 \f
 189 /* Provide a prototype to silence -Wmissing-prototypes.  */
 190 void _initialize_i386bsd_tdep (void);
 191
 192 void
 193 _initialize_i386bsd_tdep (void)
 194 {
 195   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_aout_flavour,
 196                                   i386bsd_aout_osabi_sniffer);
 197
 198   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD_AOUT,
 199                           i386fbsdaout_init_abi);
 200   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD_ELF,
 201                           i386fbsd4_init_abi);
 202 }