| 1 | /* Target-dependent code for MIPS systems running NetBSD. |
| 2 | Copyright 2002 Free Software Foundation, Inc. |
| 3 | Contributed by Wasabi Systems, 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 "gdbcore.h" |
| 24 | #include "regcache.h" |
| 25 | #include "target.h" |
| 26 | #include "value.h" |
| 27 | #include "osabi.h" |
| 28 | |
| 29 | #include "mipsnbsd-tdep.h" |
| 30 | |
| 31 | #include "solib-svr4.h" |
| 32 | |
| 33 | /* Conveniently, GDB uses the same register numbering as the |
| 34 | ptrace register structure used by NetBSD/mips. */ |
| 35 | |
| 36 | void |
| 37 | mipsnbsd_supply_reg (char *regs, int regno) |
| 38 | { |
| 39 | int i; |
| 40 | |
| 41 | for (i = 0; i <= PC_REGNUM; i++) |
| 42 | { |
| 43 | if (regno == i || regno == -1) |
| 44 | { |
| 45 | if (CANNOT_FETCH_REGISTER (i)) |
| 46 | supply_register (i, NULL); |
| 47 | else |
| 48 | supply_register (i, regs + (i * MIPS_REGSIZE)); |
| 49 | } |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | void |
| 54 | mipsnbsd_fill_reg (char *regs, int regno) |
| 55 | { |
| 56 | int i; |
| 57 | |
| 58 | for (i = 0; i <= PC_REGNUM; i++) |
| 59 | if ((regno == i || regno == -1) && ! CANNOT_STORE_REGISTER (i)) |
| 60 | regcache_collect (i, regs + (i * MIPS_REGSIZE)); |
| 61 | } |
| 62 | |
| 63 | void |
| 64 | mipsnbsd_supply_fpreg (char *fpregs, int regno) |
| 65 | { |
| 66 | int i; |
| 67 | |
| 68 | for (i = FP0_REGNUM; i <= FCRIR_REGNUM; i++) |
| 69 | { |
| 70 | if (regno == i || regno == -1) |
| 71 | { |
| 72 | if (CANNOT_FETCH_REGISTER (i)) |
| 73 | supply_register (i, NULL); |
| 74 | else |
| 75 | supply_register (i, fpregs + ((i - FP0_REGNUM) * MIPS_REGSIZE)); |
| 76 | } |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | void |
| 81 | mipsnbsd_fill_fpreg (char *fpregs, int regno) |
| 82 | { |
| 83 | int i; |
| 84 | |
| 85 | for (i = FP0_REGNUM; i <= FCRCS_REGNUM; i++) |
| 86 | if ((regno == i || regno == -1) && ! CANNOT_STORE_REGISTER (i)) |
| 87 | regcache_collect (i, fpregs + ((i - FP0_REGNUM) * MIPS_REGSIZE)); |
| 88 | } |
| 89 | |
| 90 | static void |
| 91 | fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which, |
| 92 | CORE_ADDR ignore) |
| 93 | { |
| 94 | char *regs, *fpregs; |
| 95 | |
| 96 | /* We get everything from one section. */ |
| 97 | if (which != 0) |
| 98 | return; |
| 99 | |
| 100 | regs = core_reg_sect; |
| 101 | fpregs = core_reg_sect + SIZEOF_STRUCT_REG; |
| 102 | |
| 103 | /* Integer registers. */ |
| 104 | mipsnbsd_supply_reg (regs, -1); |
| 105 | |
| 106 | /* Floating point registers. */ |
| 107 | mipsnbsd_supply_fpreg (regs, -1); |
| 108 | } |
| 109 | |
| 110 | static void |
| 111 | fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size, int which, |
| 112 | CORE_ADDR ignore) |
| 113 | { |
| 114 | switch (which) |
| 115 | { |
| 116 | case 0: /* Integer registers. */ |
| 117 | if (core_reg_size != SIZEOF_STRUCT_REG) |
| 118 | warning ("Wrong size register set in core file."); |
| 119 | else |
| 120 | mipsnbsd_supply_reg (core_reg_sect, -1); |
| 121 | break; |
| 122 | |
| 123 | case 2: /* Floating point registers. */ |
| 124 | if (core_reg_size != SIZEOF_STRUCT_FPREG) |
| 125 | warning ("Wrong size register set in core file."); |
| 126 | else |
| 127 | mipsnbsd_supply_fpreg (core_reg_sect, -1); |
| 128 | break; |
| 129 | |
| 130 | default: |
| 131 | /* Don't know what kind of register request this is; just ignore it. */ |
| 132 | break; |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | static struct core_fns mipsnbsd_core_fns = |
| 137 | { |
| 138 | bfd_target_unknown_flavour, /* core_flavour */ |
| 139 | default_check_format, /* check_format */ |
| 140 | default_core_sniffer, /* core_sniffer */ |
| 141 | fetch_core_registers, /* core_read_registers */ |
| 142 | NULL /* next */ |
| 143 | }; |
| 144 | |
| 145 | static struct core_fns mipsnbsd_elfcore_fns = |
| 146 | { |
| 147 | bfd_target_elf_flavour, /* core_flavour */ |
| 148 | default_check_format, /* check_format */ |
| 149 | default_core_sniffer, /* core_sniffer */ |
| 150 | fetch_elfcore_registers, /* core_read_registers */ |
| 151 | NULL /* next */ |
| 152 | }; |
| 153 | |
| 154 | /* Under NetBSD/mips, signal handler invocations can be identified by the |
| 155 | designated code sequence that is used to return from a signal handler. |
| 156 | In particular, the return address of a signal handler points to the |
| 157 | following code sequence: |
| 158 | |
| 159 | addu a0, sp, 16 |
| 160 | li v0, 295 # __sigreturn14 |
| 161 | syscall |
| 162 | |
| 163 | Each instruction has a unique encoding, so we simply attempt to match |
| 164 | the instruction the PC is pointing to with any of the above instructions. |
| 165 | If there is a hit, we know the offset to the start of the designated |
| 166 | sequence and can then check whether we really are executing in the |
| 167 | signal trampoline. If not, -1 is returned, otherwise the offset from the |
| 168 | start of the return sequence is returned. */ |
| 169 | |
| 170 | #define RETCODE_NWORDS 3 |
| 171 | #define RETCODE_SIZE (RETCODE_NWORDS * 4) |
| 172 | |
| 173 | static const unsigned char sigtramp_retcode_mipsel[RETCODE_SIZE] = |
| 174 | { |
| 175 | 0x10, 0x00, 0xa4, 0x27, /* addu a0, sp, 16 */ |
| 176 | 0x27, 0x01, 0x02, 0x24, /* li v0, 295 */ |
| 177 | 0x0c, 0x00, 0x00, 0x00, /* syscall */ |
| 178 | }; |
| 179 | |
| 180 | static const unsigned char sigtramp_retcode_mipseb[RETCODE_SIZE] = |
| 181 | { |
| 182 | 0x27, 0xa4, 0x00, 0x10, /* addu a0, sp, 16 */ |
| 183 | 0x24, 0x02, 0x01, 0x27, /* li v0, 295 */ |
| 184 | 0x00, 0x00, 0x00, 0x0c, /* syscall */ |
| 185 | }; |
| 186 | |
| 187 | static LONGEST |
| 188 | mipsnbsd_sigtramp_offset (CORE_ADDR pc) |
| 189 | { |
| 190 | const char *retcode = TARGET_BYTE_ORDER == BFD_ENDIAN_BIG |
| 191 | ? sigtramp_retcode_mipseb : sigtramp_retcode_mipsel; |
| 192 | unsigned char ret[RETCODE_SIZE], w[4]; |
| 193 | LONGEST off; |
| 194 | int i; |
| 195 | |
| 196 | if (read_memory_nobpt (pc, (char *) w, sizeof (w)) != 0) |
| 197 | return -1; |
| 198 | |
| 199 | for (i = 0; i < RETCODE_NWORDS; i++) |
| 200 | { |
| 201 | if (memcmp (w, retcode + (i * 4), 4) == 0) |
| 202 | break; |
| 203 | } |
| 204 | if (i == RETCODE_NWORDS) |
| 205 | return -1; |
| 206 | |
| 207 | off = i * 4; |
| 208 | pc -= off; |
| 209 | |
| 210 | if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0) |
| 211 | return -1; |
| 212 | |
| 213 | if (memcmp (ret, retcode, RETCODE_SIZE) == 0) |
| 214 | return off; |
| 215 | |
| 216 | return -1; |
| 217 | } |
| 218 | |
| 219 | static int |
| 220 | mipsnbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name) |
| 221 | { |
| 222 | return (mipsnbsd_sigtramp_offset (pc) >= 0); |
| 223 | } |
| 224 | |
| 225 | /* Figure out where the longjmp will land. We expect that we have |
| 226 | just entered longjmp and haven't yet setup the stack frame, so |
| 227 | the args are still in the argument regs. A0_REGNUM points at the |
| 228 | jmp_buf structure from which we extract the PC that we will land |
| 229 | at. The PC is copied into *pc. This routine returns true on |
| 230 | success. */ |
| 231 | |
| 232 | #define NBSD_MIPS_JB_PC (2 * 4) |
| 233 | #define NBSD_MIPS_JB_ELEMENT_SIZE MIPS_REGSIZE |
| 234 | #define NBSD_MIPS_JB_OFFSET (NBSD_MIPS_JB_PC * \ |
| 235 | NBSD_MIPS_JB_ELEMENT_SIZE) |
| 236 | |
| 237 | static int |
| 238 | mipsnbsd_get_longjmp_target (CORE_ADDR *pc) |
| 239 | { |
| 240 | CORE_ADDR jb_addr; |
| 241 | char *buf; |
| 242 | |
| 243 | buf = alloca (NBSD_MIPS_JB_ELEMENT_SIZE); |
| 244 | |
| 245 | jb_addr = read_register (A0_REGNUM); |
| 246 | |
| 247 | if (target_read_memory (jb_addr + NBSD_MIPS_JB_OFFSET, buf, |
| 248 | NBSD_MIPS_JB_ELEMENT_SIZE)) |
| 249 | return 0; |
| 250 | |
| 251 | *pc = extract_address (buf, NBSD_MIPS_JB_ELEMENT_SIZE); |
| 252 | |
| 253 | return 1; |
| 254 | } |
| 255 | |
| 256 | static int |
| 257 | mipsnbsd_cannot_fetch_register (int regno) |
| 258 | { |
| 259 | return (regno >= FP_REGNUM |
| 260 | || regno == ZERO_REGNUM |
| 261 | || regno == FCRIR_REGNUM); |
| 262 | } |
| 263 | |
| 264 | static int |
| 265 | mipsnbsd_cannot_store_register (int regno) |
| 266 | { |
| 267 | return (regno >= FP_REGNUM |
| 268 | || regno == ZERO_REGNUM |
| 269 | || regno == FCRIR_REGNUM); |
| 270 | } |
| 271 | |
| 272 | /* NetBSD/mips uses a slightly different link_map structure from the |
| 273 | other NetBSD platforms. */ |
| 274 | static struct link_map_offsets * |
| 275 | mipsnbsd_ilp32_solib_svr4_fetch_link_map_offsets (void) |
| 276 | { |
| 277 | static struct link_map_offsets lmo; |
| 278 | static struct link_map_offsets *lmp = NULL; |
| 279 | |
| 280 | if (lmp == NULL) |
| 281 | { |
| 282 | lmp = &lmo; |
| 283 | |
| 284 | lmo.r_debug_size = 16; |
| 285 | |
| 286 | lmo.r_map_offset = 4; |
| 287 | lmo.r_map_size = 4; |
| 288 | |
| 289 | lmo.link_map_size = 24; |
| 290 | |
| 291 | lmo.l_addr_offset = 0; |
| 292 | lmo.l_addr_size = 4; |
| 293 | |
| 294 | lmo.l_name_offset = 8; |
| 295 | lmo.l_name_size = 4; |
| 296 | |
| 297 | lmo.l_next_offset = 16; |
| 298 | lmo.l_next_size = 4; |
| 299 | |
| 300 | lmo.l_prev_offset = 20; |
| 301 | lmo.l_prev_size = 4; |
| 302 | } |
| 303 | |
| 304 | return lmp; |
| 305 | } |
| 306 | |
| 307 | static struct link_map_offsets * |
| 308 | mipsnbsd_lp64_solib_svr4_fetch_link_map_offsets (void) |
| 309 | { |
| 310 | static struct link_map_offsets lmo; |
| 311 | static struct link_map_offsets *lmp = NULL; |
| 312 | |
| 313 | if (lmp == NULL) |
| 314 | { |
| 315 | lmp = &lmo; |
| 316 | |
| 317 | lmo.r_debug_size = 32; |
| 318 | |
| 319 | lmo.r_map_offset = 8; |
| 320 | lmo.r_map_size = 8; |
| 321 | |
| 322 | lmo.link_map_size = 48; |
| 323 | |
| 324 | lmo.l_addr_offset = 0; |
| 325 | lmo.l_addr_size = 8; |
| 326 | |
| 327 | lmo.l_name_offset = 16; |
| 328 | lmo.l_name_size = 8; |
| 329 | |
| 330 | lmo.l_next_offset = 32; |
| 331 | lmo.l_next_size = 8; |
| 332 | |
| 333 | lmo.l_prev_offset = 40; |
| 334 | lmo.l_prev_size = 8; |
| 335 | } |
| 336 | |
| 337 | return lmp; |
| 338 | } |
| 339 | |
| 340 | static void |
| 341 | mipsnbsd_init_abi (struct gdbarch_info info, |
| 342 | struct gdbarch *gdbarch) |
| 343 | { |
| 344 | set_gdbarch_pc_in_sigtramp (gdbarch, mipsnbsd_pc_in_sigtramp); |
| 345 | |
| 346 | set_gdbarch_get_longjmp_target (gdbarch, mipsnbsd_get_longjmp_target); |
| 347 | |
| 348 | set_gdbarch_cannot_fetch_register (gdbarch, mipsnbsd_cannot_fetch_register); |
| 349 | set_gdbarch_cannot_store_register (gdbarch, mipsnbsd_cannot_store_register); |
| 350 | |
| 351 | set_gdbarch_software_single_step (gdbarch, mips_software_single_step); |
| 352 | |
| 353 | set_solib_svr4_fetch_link_map_offsets (gdbarch, |
| 354 | gdbarch_ptr_bit (gdbarch) == 32 ? |
| 355 | mipsnbsd_ilp32_solib_svr4_fetch_link_map_offsets : |
| 356 | mipsnbsd_lp64_solib_svr4_fetch_link_map_offsets); |
| 357 | } |
| 358 | |
| 359 | void |
| 360 | _initialize_mipsnbsd_tdep (void) |
| 361 | { |
| 362 | gdbarch_register_osabi (bfd_arch_mips, GDB_OSABI_NETBSD_ELF, |
| 363 | mipsnbsd_init_abi); |
| 364 | |
| 365 | add_core_fns (&mipsnbsd_core_fns); |
| 366 | add_core_fns (&mipsnbsd_elfcore_fns); |
| 367 | } |