| 1 | /* Target-dependent code for NetBSD/i386. |
| 2 | |
| 3 | Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, |
| 4 | 2003, 2004 |
| 5 | Free Software Foundation, Inc. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 2 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program; if not, write to the Free Software |
| 21 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 22 | Boston, MA 02111-1307, USA. */ |
| 23 | |
| 24 | #include "defs.h" |
| 25 | #include "arch-utils.h" |
| 26 | #include "frame.h" |
| 27 | #include "gdbcore.h" |
| 28 | #include "regcache.h" |
| 29 | #include "regset.h" |
| 30 | #include "osabi.h" |
| 31 | #include "symtab.h" |
| 32 | |
| 33 | #include "gdb_assert.h" |
| 34 | #include "gdb_string.h" |
| 35 | |
| 36 | #include "i386-tdep.h" |
| 37 | #include "i387-tdep.h" |
| 38 | #include "nbsd-tdep.h" |
| 39 | #include "solib-svr4.h" |
| 40 | |
| 41 | /* From <machine/reg.h>. */ |
| 42 | static int i386nbsd_r_reg_offset[] = |
| 43 | { |
| 44 | 0 * 4, /* %eax */ |
| 45 | 1 * 4, /* %ecx */ |
| 46 | 2 * 4, /* %edx */ |
| 47 | 3 * 4, /* %ebx */ |
| 48 | 4 * 4, /* %esp */ |
| 49 | 5 * 4, /* %ebp */ |
| 50 | 6 * 4, /* %esi */ |
| 51 | 7 * 4, /* %edi */ |
| 52 | 8 * 4, /* %eip */ |
| 53 | 9 * 4, /* %eflags */ |
| 54 | 10 * 4, /* %cs */ |
| 55 | 11 * 4, /* %ss */ |
| 56 | 12 * 4, /* %ds */ |
| 57 | 13 * 4, /* %es */ |
| 58 | 14 * 4, /* %fs */ |
| 59 | 15 * 4 /* %gs */ |
| 60 | }; |
| 61 | |
| 62 | static void |
| 63 | i386nbsd_aout_supply_regset (const struct regset *regset, |
| 64 | struct regcache *regcache, int regnum, |
| 65 | const void *regs, size_t len) |
| 66 | { |
| 67 | const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch); |
| 68 | |
| 69 | gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE); |
| 70 | |
| 71 | i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset); |
| 72 | i387_supply_fsave (regcache, regnum, (char *) regs + tdep->sizeof_gregset); |
| 73 | } |
| 74 | |
| 75 | static const struct regset * |
| 76 | i386nbsd_aout_regset_from_core_section (struct gdbarch *gdbarch, |
| 77 | const char *sect_name, |
| 78 | size_t sect_size) |
| 79 | { |
| 80 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 81 | |
| 82 | /* NetBSD a.out core dumps don't use seperate register sets for the |
| 83 | general-purpose and floating-point registers. */ |
| 84 | |
| 85 | if (strcmp (sect_name, ".reg") == 0 |
| 86 | && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE) |
| 87 | { |
| 88 | if (tdep->gregset == NULL) |
| 89 | tdep->gregset = |
| 90 | regset_alloc (gdbarch, i386nbsd_aout_supply_regset, NULL); |
| 91 | return tdep->gregset; |
| 92 | } |
| 93 | |
| 94 | return NULL; |
| 95 | } |
| 96 | |
| 97 | /* Under NetBSD/i386, signal handler invocations can be identified by the |
| 98 | designated code sequence that is used to return from a signal handler. |
| 99 | In particular, the return address of a signal handler points to the |
| 100 | following code sequence: |
| 101 | |
| 102 | leal 0x10(%esp), %eax |
| 103 | pushl %eax |
| 104 | pushl %eax |
| 105 | movl $0x127, %eax # __sigreturn14 |
| 106 | int $0x80 |
| 107 | |
| 108 | Each instruction has a unique encoding, so we simply attempt to match |
| 109 | the instruction the PC is pointing to with any of the above instructions. |
| 110 | If there is a hit, we know the offset to the start of the designated |
| 111 | sequence and can then check whether we really are executing in the |
| 112 | signal trampoline. If not, -1 is returned, otherwise the offset from the |
| 113 | start of the return sequence is returned. */ |
| 114 | #define RETCODE_INSN1 0x8d |
| 115 | #define RETCODE_INSN2 0x50 |
| 116 | #define RETCODE_INSN3 0x50 |
| 117 | #define RETCODE_INSN4 0xb8 |
| 118 | #define RETCODE_INSN5 0xcd |
| 119 | |
| 120 | #define RETCODE_INSN2_OFF 4 |
| 121 | #define RETCODE_INSN3_OFF 5 |
| 122 | #define RETCODE_INSN4_OFF 6 |
| 123 | #define RETCODE_INSN5_OFF 11 |
| 124 | |
| 125 | static const unsigned char sigtramp_retcode[] = |
| 126 | { |
| 127 | RETCODE_INSN1, 0x44, 0x24, 0x10, |
| 128 | RETCODE_INSN2, |
| 129 | RETCODE_INSN3, |
| 130 | RETCODE_INSN4, 0x27, 0x01, 0x00, 0x00, |
| 131 | RETCODE_INSN5, 0x80, |
| 132 | }; |
| 133 | |
| 134 | static LONGEST |
| 135 | i386nbsd_sigtramp_offset (struct frame_info *next_frame) |
| 136 | { |
| 137 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
| 138 | unsigned char ret[sizeof(sigtramp_retcode)], insn; |
| 139 | LONGEST off; |
| 140 | int i; |
| 141 | |
| 142 | if (!safe_frame_unwind_memory (next_frame, pc, &insn, 1)) |
| 143 | return -1; |
| 144 | |
| 145 | switch (insn) |
| 146 | { |
| 147 | case RETCODE_INSN1: |
| 148 | off = 0; |
| 149 | break; |
| 150 | |
| 151 | case RETCODE_INSN2: |
| 152 | /* INSN2 and INSN3 are the same. Read at the location of PC+1 |
| 153 | to determine if we're actually looking at INSN2 or INSN3. */ |
| 154 | if (!safe_frame_unwind_memory (next_frame, pc + 1, &insn, 1)) |
| 155 | return -1; |
| 156 | |
| 157 | if (insn == RETCODE_INSN3) |
| 158 | off = RETCODE_INSN2_OFF; |
| 159 | else |
| 160 | off = RETCODE_INSN3_OFF; |
| 161 | break; |
| 162 | |
| 163 | case RETCODE_INSN4: |
| 164 | off = RETCODE_INSN4_OFF; |
| 165 | break; |
| 166 | |
| 167 | case RETCODE_INSN5: |
| 168 | off = RETCODE_INSN5_OFF; |
| 169 | break; |
| 170 | |
| 171 | default: |
| 172 | return -1; |
| 173 | } |
| 174 | |
| 175 | pc -= off; |
| 176 | |
| 177 | if (!safe_frame_unwind_memory (next_frame, pc, ret, sizeof (ret))) |
| 178 | return -1; |
| 179 | |
| 180 | if (memcmp (ret, sigtramp_retcode, sizeof (ret)) == 0) |
| 181 | return off; |
| 182 | |
| 183 | return -1; |
| 184 | } |
| 185 | |
| 186 | /* Return whether the frame preceding NEXT_FRAME corresponds to a |
| 187 | NetBSD sigtramp routine. */ |
| 188 | |
| 189 | static int |
| 190 | i386nbsd_sigtramp_p (struct frame_info *next_frame) |
| 191 | { |
| 192 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
| 193 | char *name; |
| 194 | |
| 195 | find_pc_partial_function (pc, &name, NULL, NULL); |
| 196 | return (nbsd_pc_in_sigtramp (pc, name) |
| 197 | || i386nbsd_sigtramp_offset (next_frame) >= 0); |
| 198 | } |
| 199 | |
| 200 | /* From <machine/signal.h>. */ |
| 201 | int i386nbsd_sc_reg_offset[] = |
| 202 | { |
| 203 | 10 * 4, /* %eax */ |
| 204 | 9 * 4, /* %ecx */ |
| 205 | 8 * 4, /* %edx */ |
| 206 | 7 * 4, /* %ebx */ |
| 207 | 14 * 4, /* %esp */ |
| 208 | 6 * 4, /* %ebp */ |
| 209 | 5 * 4, /* %esi */ |
| 210 | 4 * 4, /* %edi */ |
| 211 | 11 * 4, /* %eip */ |
| 212 | 13 * 4, /* %eflags */ |
| 213 | 12 * 4, /* %cs */ |
| 214 | 15 * 4, /* %ss */ |
| 215 | 3 * 4, /* %ds */ |
| 216 | 2 * 4, /* %es */ |
| 217 | 1 * 4, /* %fs */ |
| 218 | 0 * 4 /* %gs */ |
| 219 | }; |
| 220 | |
| 221 | static void |
| 222 | i386nbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 223 | { |
| 224 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 225 | |
| 226 | /* Obviously NetBSD is BSD-based. */ |
| 227 | i386bsd_init_abi (info, gdbarch); |
| 228 | |
| 229 | /* NetBSD has a different `struct reg'. */ |
| 230 | tdep->gregset_reg_offset = i386nbsd_r_reg_offset; |
| 231 | tdep->gregset_num_regs = ARRAY_SIZE (i386nbsd_r_reg_offset); |
| 232 | tdep->sizeof_gregset = 16 * 4; |
| 233 | |
| 234 | /* NetBSD has different signal trampoline conventions. */ |
| 235 | tdep->sigtramp_start = 0; |
| 236 | tdep->sigtramp_end = 0; |
| 237 | tdep->sigtramp_p = i386nbsd_sigtramp_p; |
| 238 | |
| 239 | /* NetBSD uses -freg-struct-return by default. */ |
| 240 | tdep->struct_return = reg_struct_return; |
| 241 | |
| 242 | /* NetBSD has a `struct sigcontext' that's different from the |
| 243 | original 4.3 BSD. */ |
| 244 | tdep->sc_reg_offset = i386nbsd_sc_reg_offset; |
| 245 | tdep->sc_num_regs = ARRAY_SIZE (i386nbsd_sc_reg_offset); |
| 246 | } |
| 247 | |
| 248 | /* NetBSD a.out. */ |
| 249 | |
| 250 | static void |
| 251 | i386nbsdaout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 252 | { |
| 253 | i386nbsd_init_abi (info, gdbarch); |
| 254 | |
| 255 | /* NetBSD a.out has a single register set. */ |
| 256 | set_gdbarch_regset_from_core_section |
| 257 | (gdbarch, i386nbsd_aout_regset_from_core_section); |
| 258 | } |
| 259 | |
| 260 | /* NetBSD ELF. */ |
| 261 | |
| 262 | static void |
| 263 | i386nbsdelf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 264 | { |
| 265 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 266 | |
| 267 | /* It's still NetBSD. */ |
| 268 | i386nbsd_init_abi (info, gdbarch); |
| 269 | |
| 270 | /* But ELF-based. */ |
| 271 | i386_elf_init_abi (info, gdbarch); |
| 272 | |
| 273 | /* NetBSD ELF uses SVR4-style shared libraries. */ |
| 274 | set_solib_svr4_fetch_link_map_offsets |
| 275 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
| 276 | |
| 277 | /* NetBSD ELF uses -fpcc-struct-return by default. */ |
| 278 | tdep->struct_return = pcc_struct_return; |
| 279 | } |
| 280 | |
| 281 | void |
| 282 | _initialize_i386nbsd_tdep (void) |
| 283 | { |
| 284 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_AOUT, |
| 285 | i386nbsdaout_init_abi); |
| 286 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_NETBSD_ELF, |
| 287 | i386nbsdelf_init_abi); |
| 288 | } |