| 1 | /* Target-dependent code for NetBSD/mips. |
| 2 | |
| 3 | Copyright (C) 2002, 2003, 2004, 2006, 2007, 2008 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | Contributed by Wasabi Systems, Inc. |
| 7 | |
| 8 | This file is part of GDB. |
| 9 | |
| 10 | This program is free software; you can redistribute it and/or modify |
| 11 | it under the terms of the GNU General Public License as published by |
| 12 | the Free Software Foundation; either version 3 of the License, or |
| 13 | (at your option) any later version. |
| 14 | |
| 15 | This program is distributed in the hope that it will be useful, |
| 16 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | GNU General Public License for more details. |
| 19 | |
| 20 | You should have received a copy of the GNU General Public License |
| 21 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "gdbcore.h" |
| 25 | #include "regcache.h" |
| 26 | #include "regset.h" |
| 27 | #include "target.h" |
| 28 | #include "value.h" |
| 29 | #include "osabi.h" |
| 30 | |
| 31 | #include "gdb_assert.h" |
| 32 | #include "gdb_string.h" |
| 33 | |
| 34 | #include "nbsd-tdep.h" |
| 35 | #include "mipsnbsd-tdep.h" |
| 36 | #include "mips-tdep.h" |
| 37 | |
| 38 | #include "solib-svr4.h" |
| 39 | |
| 40 | /* Shorthand for some register numbers used below. */ |
| 41 | #define MIPS_PC_REGNUM MIPS_EMBED_PC_REGNUM |
| 42 | #define MIPS_FP0_REGNUM MIPS_EMBED_FP0_REGNUM |
| 43 | #define MIPS_FSR_REGNUM MIPS_EMBED_FP0_REGNUM + 32 |
| 44 | |
| 45 | /* Core file support. */ |
| 46 | |
| 47 | /* Number of registers in `struct reg' from <machine/reg.h>. */ |
| 48 | #define MIPSNBSD_NUM_GREGS 38 |
| 49 | |
| 50 | /* Number of registers in `struct fpreg' from <machine/reg.h>. */ |
| 51 | #define MIPSNBSD_NUM_FPREGS 33 |
| 52 | |
| 53 | /* Supply register REGNUM from the buffer specified by FPREGS and LEN |
| 54 | in the floating-point register set REGSET to register cache |
| 55 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 56 | |
| 57 | static void |
| 58 | mipsnbsd_supply_fpregset (const struct regset *regset, |
| 59 | struct regcache *regcache, |
| 60 | int regnum, const void *fpregs, size_t len) |
| 61 | { |
| 62 | size_t regsize = mips_isa_regsize (get_regcache_arch (regcache)); |
| 63 | const char *regs = fpregs; |
| 64 | int i; |
| 65 | |
| 66 | gdb_assert (len >= MIPSNBSD_NUM_FPREGS * regsize); |
| 67 | |
| 68 | for (i = MIPS_FP0_REGNUM; i <= MIPS_FSR_REGNUM; i++) |
| 69 | { |
| 70 | if (regnum == i || regnum == -1) |
| 71 | regcache_raw_supply (regcache, i, |
| 72 | regs + (i - MIPS_FP0_REGNUM) * regsize); |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | /* Supply register REGNUM from the buffer specified by GREGS and LEN |
| 77 | in the general-purpose register set REGSET to register cache |
| 78 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 79 | |
| 80 | static void |
| 81 | mipsnbsd_supply_gregset (const struct regset *regset, |
| 82 | struct regcache *regcache, int regnum, |
| 83 | const void *gregs, size_t len) |
| 84 | { |
| 85 | size_t regsize = mips_isa_regsize (get_regcache_arch (regcache)); |
| 86 | const char *regs = gregs; |
| 87 | int i; |
| 88 | |
| 89 | gdb_assert (len >= MIPSNBSD_NUM_GREGS * regsize); |
| 90 | |
| 91 | for (i = 0; i <= MIPS_PC_REGNUM; i++) |
| 92 | { |
| 93 | if (regnum == i || regnum == -1) |
| 94 | regcache_raw_supply (regcache, i, regs + i * regsize); |
| 95 | } |
| 96 | |
| 97 | if (len >= (MIPSNBSD_NUM_GREGS + MIPSNBSD_NUM_FPREGS) * regsize) |
| 98 | { |
| 99 | regs += MIPSNBSD_NUM_GREGS * regsize; |
| 100 | len -= MIPSNBSD_NUM_GREGS * regsize; |
| 101 | mipsnbsd_supply_fpregset (regset, regcache, regnum, regs, len); |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | /* NetBSD/mips register sets. */ |
| 106 | |
| 107 | static struct regset mipsnbsd_gregset = |
| 108 | { |
| 109 | NULL, |
| 110 | mipsnbsd_supply_gregset |
| 111 | }; |
| 112 | |
| 113 | static struct regset mipsnbsd_fpregset = |
| 114 | { |
| 115 | NULL, |
| 116 | mipsnbsd_supply_fpregset |
| 117 | }; |
| 118 | |
| 119 | /* Return the appropriate register set for the core section identified |
| 120 | by SECT_NAME and SECT_SIZE. */ |
| 121 | |
| 122 | static const struct regset * |
| 123 | mipsnbsd_regset_from_core_section (struct gdbarch *gdbarch, |
| 124 | const char *sect_name, size_t sect_size) |
| 125 | { |
| 126 | size_t regsize = mips_isa_regsize (gdbarch); |
| 127 | |
| 128 | if (strcmp (sect_name, ".reg") == 0 |
| 129 | && sect_size >= MIPSNBSD_NUM_GREGS * regsize) |
| 130 | return &mipsnbsd_gregset; |
| 131 | |
| 132 | if (strcmp (sect_name, ".reg2") == 0 |
| 133 | && sect_size >= MIPSNBSD_NUM_FPREGS * regsize) |
| 134 | return &mipsnbsd_fpregset; |
| 135 | |
| 136 | return NULL; |
| 137 | } |
| 138 | \f |
| 139 | |
| 140 | /* Conveniently, GDB uses the same register numbering as the |
| 141 | ptrace register structure used by NetBSD/mips. */ |
| 142 | |
| 143 | void |
| 144 | mipsnbsd_supply_reg (struct regcache *regcache, const char *regs, int regno) |
| 145 | { |
| 146 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 147 | int i; |
| 148 | |
| 149 | for (i = 0; i <= gdbarch_pc_regnum (gdbarch); i++) |
| 150 | { |
| 151 | if (regno == i || regno == -1) |
| 152 | { |
| 153 | if (gdbarch_cannot_fetch_register (gdbarch, i)) |
| 154 | regcache_raw_supply (regcache, i, NULL); |
| 155 | else |
| 156 | regcache_raw_supply (regcache, i, |
| 157 | regs + (i * mips_isa_regsize (gdbarch))); |
| 158 | } |
| 159 | } |
| 160 | } |
| 161 | |
| 162 | void |
| 163 | mipsnbsd_fill_reg (const struct regcache *regcache, char *regs, int regno) |
| 164 | { |
| 165 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 166 | int i; |
| 167 | |
| 168 | for (i = 0; i <= gdbarch_pc_regnum (gdbarch); i++) |
| 169 | if ((regno == i || regno == -1) |
| 170 | && ! gdbarch_cannot_store_register (gdbarch, i)) |
| 171 | regcache_raw_collect (regcache, i, |
| 172 | regs + (i * mips_isa_regsize (gdbarch))); |
| 173 | } |
| 174 | |
| 175 | void |
| 176 | mipsnbsd_supply_fpreg (struct regcache *regcache, const char *fpregs, int regno) |
| 177 | { |
| 178 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 179 | int i; |
| 180 | |
| 181 | for (i = gdbarch_fp0_regnum (gdbarch); |
| 182 | i <= mips_regnum (gdbarch)->fp_implementation_revision; |
| 183 | i++) |
| 184 | { |
| 185 | if (regno == i || regno == -1) |
| 186 | { |
| 187 | if (gdbarch_cannot_fetch_register (gdbarch, i)) |
| 188 | regcache_raw_supply (regcache, i, NULL); |
| 189 | else |
| 190 | regcache_raw_supply (regcache, i, |
| 191 | fpregs |
| 192 | + ((i - gdbarch_fp0_regnum (gdbarch)) |
| 193 | * mips_isa_regsize (gdbarch))); |
| 194 | } |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | void |
| 199 | mipsnbsd_fill_fpreg (const struct regcache *regcache, char *fpregs, int regno) |
| 200 | { |
| 201 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 202 | int i; |
| 203 | |
| 204 | for (i = gdbarch_fp0_regnum (gdbarch); |
| 205 | i <= mips_regnum (gdbarch)->fp_control_status; |
| 206 | i++) |
| 207 | if ((regno == i || regno == -1) |
| 208 | && ! gdbarch_cannot_store_register (gdbarch, i)) |
| 209 | regcache_raw_collect (regcache, i, |
| 210 | fpregs + ((i - gdbarch_fp0_regnum (gdbarch)) |
| 211 | * mips_isa_regsize (gdbarch))); |
| 212 | } |
| 213 | |
| 214 | /* Under NetBSD/mips, signal handler invocations can be identified by the |
| 215 | designated code sequence that is used to return from a signal handler. |
| 216 | In particular, the return address of a signal handler points to the |
| 217 | following code sequence: |
| 218 | |
| 219 | addu a0, sp, 16 |
| 220 | li v0, 295 # __sigreturn14 |
| 221 | syscall |
| 222 | |
| 223 | Each instruction has a unique encoding, so we simply attempt to match |
| 224 | the instruction the PC is pointing to with any of the above instructions. |
| 225 | If there is a hit, we know the offset to the start of the designated |
| 226 | sequence and can then check whether we really are executing in the |
| 227 | signal trampoline. If not, -1 is returned, otherwise the offset from the |
| 228 | start of the return sequence is returned. */ |
| 229 | |
| 230 | #define RETCODE_NWORDS 3 |
| 231 | #define RETCODE_SIZE (RETCODE_NWORDS * 4) |
| 232 | |
| 233 | static const unsigned char sigtramp_retcode_mipsel[RETCODE_SIZE] = |
| 234 | { |
| 235 | 0x10, 0x00, 0xa4, 0x27, /* addu a0, sp, 16 */ |
| 236 | 0x27, 0x01, 0x02, 0x24, /* li v0, 295 */ |
| 237 | 0x0c, 0x00, 0x00, 0x00, /* syscall */ |
| 238 | }; |
| 239 | |
| 240 | static const unsigned char sigtramp_retcode_mipseb[RETCODE_SIZE] = |
| 241 | { |
| 242 | 0x27, 0xa4, 0x00, 0x10, /* addu a0, sp, 16 */ |
| 243 | 0x24, 0x02, 0x01, 0x27, /* li v0, 295 */ |
| 244 | 0x00, 0x00, 0x00, 0x0c, /* syscall */ |
| 245 | }; |
| 246 | |
| 247 | static LONGEST |
| 248 | mipsnbsd_sigtramp_offset (struct frame_info *this_frame) |
| 249 | { |
| 250 | CORE_ADDR pc = get_frame_pc (this_frame); |
| 251 | const char *retcode = gdbarch_byte_order (get_frame_arch (this_frame)) |
| 252 | == BFD_ENDIAN_BIG ? sigtramp_retcode_mipseb : |
| 253 | sigtramp_retcode_mipsel; |
| 254 | unsigned char ret[RETCODE_SIZE], w[4]; |
| 255 | LONGEST off; |
| 256 | int i; |
| 257 | |
| 258 | if (!safe_frame_unwind_memory (this_frame, pc, w, sizeof (w))) |
| 259 | return -1; |
| 260 | |
| 261 | for (i = 0; i < RETCODE_NWORDS; i++) |
| 262 | { |
| 263 | if (memcmp (w, retcode + (i * 4), 4) == 0) |
| 264 | break; |
| 265 | } |
| 266 | if (i == RETCODE_NWORDS) |
| 267 | return -1; |
| 268 | |
| 269 | off = i * 4; |
| 270 | pc -= off; |
| 271 | |
| 272 | if (!safe_frame_unwind_memory (this_frame, pc, ret, sizeof (ret))) |
| 273 | return -1; |
| 274 | |
| 275 | if (memcmp (ret, retcode, RETCODE_SIZE) == 0) |
| 276 | return off; |
| 277 | |
| 278 | return -1; |
| 279 | } |
| 280 | |
| 281 | /* Figure out where the longjmp will land. We expect that we have |
| 282 | just entered longjmp and haven't yet setup the stack frame, so the |
| 283 | args are still in the argument regs. MIPS_A0_REGNUM points at the |
| 284 | jmp_buf structure from which we extract the PC that we will land |
| 285 | at. The PC is copied into *pc. This routine returns true on |
| 286 | success. */ |
| 287 | |
| 288 | #define NBSD_MIPS_JB_PC (2 * 4) |
| 289 | #define NBSD_MIPS_JB_ELEMENT_SIZE mips_isa_regsize (current_gdbarch) |
| 290 | #define NBSD_MIPS_JB_OFFSET (NBSD_MIPS_JB_PC * \ |
| 291 | NBSD_MIPS_JB_ELEMENT_SIZE) |
| 292 | |
| 293 | static int |
| 294 | mipsnbsd_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc) |
| 295 | { |
| 296 | CORE_ADDR jb_addr; |
| 297 | char *buf; |
| 298 | |
| 299 | buf = alloca (NBSD_MIPS_JB_ELEMENT_SIZE); |
| 300 | |
| 301 | jb_addr = get_frame_register_unsigned (frame, MIPS_A0_REGNUM); |
| 302 | |
| 303 | if (target_read_memory (jb_addr + NBSD_MIPS_JB_OFFSET, buf, |
| 304 | NBSD_MIPS_JB_ELEMENT_SIZE)) |
| 305 | return 0; |
| 306 | |
| 307 | *pc = extract_unsigned_integer (buf, NBSD_MIPS_JB_ELEMENT_SIZE); |
| 308 | |
| 309 | return 1; |
| 310 | } |
| 311 | |
| 312 | static int |
| 313 | mipsnbsd_cannot_fetch_register (struct gdbarch *gdbarch, int regno) |
| 314 | { |
| 315 | return (regno == MIPS_ZERO_REGNUM |
| 316 | || regno == mips_regnum (gdbarch)->fp_implementation_revision); |
| 317 | } |
| 318 | |
| 319 | static int |
| 320 | mipsnbsd_cannot_store_register (struct gdbarch *gdbarch, int regno) |
| 321 | { |
| 322 | return (regno == MIPS_ZERO_REGNUM |
| 323 | || regno == mips_regnum (gdbarch)->fp_implementation_revision); |
| 324 | } |
| 325 | |
| 326 | /* Shared library support. */ |
| 327 | |
| 328 | /* NetBSD/mips uses a slightly different `struct link_map' than the |
| 329 | other NetBSD platforms. */ |
| 330 | |
| 331 | static struct link_map_offsets * |
| 332 | mipsnbsd_ilp32_fetch_link_map_offsets (void) |
| 333 | { |
| 334 | static struct link_map_offsets lmo; |
| 335 | static struct link_map_offsets *lmp = NULL; |
| 336 | |
| 337 | if (lmp == NULL) |
| 338 | { |
| 339 | lmp = &lmo; |
| 340 | |
| 341 | lmo.r_version_offset = 0; |
| 342 | lmo.r_version_size = 4; |
| 343 | lmo.r_map_offset = 4; |
| 344 | lmo.r_brk_offset = 8; |
| 345 | lmo.r_ldsomap_offset = -1; |
| 346 | |
| 347 | /* Everything we need is in the first 24 bytes. */ |
| 348 | lmo.link_map_size = 24; |
| 349 | lmo.l_addr_offset = 4; |
| 350 | lmo.l_name_offset = 8; |
| 351 | lmo.l_ld_offset = 12; |
| 352 | lmo.l_next_offset = 16; |
| 353 | lmo.l_prev_offset = 20; |
| 354 | } |
| 355 | |
| 356 | return lmp; |
| 357 | } |
| 358 | |
| 359 | static struct link_map_offsets * |
| 360 | mipsnbsd_lp64_fetch_link_map_offsets (void) |
| 361 | { |
| 362 | static struct link_map_offsets lmo; |
| 363 | static struct link_map_offsets *lmp = NULL; |
| 364 | |
| 365 | if (lmp == NULL) |
| 366 | { |
| 367 | lmp = &lmo; |
| 368 | |
| 369 | lmo.r_version_offset = 0; |
| 370 | lmo.r_version_size = 4; |
| 371 | lmo.r_map_offset = 8; |
| 372 | lmo.r_brk_offset = 16; |
| 373 | lmo.r_ldsomap_offset = -1; |
| 374 | |
| 375 | /* Everything we need is in the first 40 bytes. */ |
| 376 | lmo.link_map_size = 48; |
| 377 | lmo.l_addr_offset = 0; |
| 378 | lmo.l_name_offset = 16; |
| 379 | lmo.l_ld_offset = 24; |
| 380 | lmo.l_next_offset = 32; |
| 381 | lmo.l_prev_offset = 40; |
| 382 | } |
| 383 | |
| 384 | return lmp; |
| 385 | } |
| 386 | \f |
| 387 | |
| 388 | static void |
| 389 | mipsnbsd_init_abi (struct gdbarch_info info, |
| 390 | struct gdbarch *gdbarch) |
| 391 | { |
| 392 | set_gdbarch_regset_from_core_section |
| 393 | (gdbarch, mipsnbsd_regset_from_core_section); |
| 394 | |
| 395 | set_gdbarch_get_longjmp_target (gdbarch, mipsnbsd_get_longjmp_target); |
| 396 | |
| 397 | set_gdbarch_cannot_fetch_register (gdbarch, mipsnbsd_cannot_fetch_register); |
| 398 | set_gdbarch_cannot_store_register (gdbarch, mipsnbsd_cannot_store_register); |
| 399 | |
| 400 | set_gdbarch_software_single_step (gdbarch, mips_software_single_step); |
| 401 | |
| 402 | /* NetBSD/mips has SVR4-style shared libraries. */ |
| 403 | set_solib_svr4_fetch_link_map_offsets |
| 404 | (gdbarch, (gdbarch_ptr_bit (gdbarch) == 32 ? |
| 405 | mipsnbsd_ilp32_fetch_link_map_offsets : |
| 406 | mipsnbsd_lp64_fetch_link_map_offsets)); |
| 407 | } |
| 408 | \f |
| 409 | |
| 410 | static enum gdb_osabi |
| 411 | mipsnbsd_core_osabi_sniffer (bfd *abfd) |
| 412 | { |
| 413 | if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0) |
| 414 | return GDB_OSABI_NETBSD_ELF; |
| 415 | |
| 416 | return GDB_OSABI_UNKNOWN; |
| 417 | } |
| 418 | |
| 419 | void |
| 420 | _initialize_mipsnbsd_tdep (void) |
| 421 | { |
| 422 | gdbarch_register_osabi (bfd_arch_mips, 0, GDB_OSABI_NETBSD_ELF, |
| 423 | mipsnbsd_init_abi); |
| 424 | } |