1 /* Target-dependent code for OpenBSD/amd64. 2 3 Copyright 2003, 2004, 2005 Free Software Foundation, 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 "frame.h" 24 #include "frame-unwind.h" 25 #include "gdbcore.h" 26 #include "symtab.h" 27 #include "objfiles.h" 28 #include "osabi.h" 29 #include "regcache.h" 30 #include "regset.h" 31 #include "target.h" 32 #include "trad-frame.h" 33 34 #include "gdb_assert.h" 35 #include "gdb_string.h" 36 37 #include "amd64-tdep.h" 38 #include "i387-tdep.h" 39 #include "solib-svr4.h" 40 #include "bsd-uthread.h" 41 42 /* Support for core dumps. */ 43 44 static void 45 amd64obsd_supply_regset (const struct regset *regset, 46 struct regcache *regcache, int regnum, 47 const void *regs, size_t len) 48 { 49 const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch); 50 51 gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE); 52 53 i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset); 54 amd64_supply_fxsave (regcache, regnum, (char *)regs + tdep->sizeof_gregset); 55 } 56 57 static const struct regset * 58 amd64obsd_regset_from_core_section (struct gdbarch *gdbarch, 59 const char *sect_name, size_t sect_size) 60 { 61 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 62 63 /* OpenBSD core dumps don't use seperate register sets for the 64 general-purpose and floating-point registers. */ 65 66 if (strcmp (sect_name, ".reg") == 0 67 && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE) 68 { 69 if (tdep->gregset == NULL) 70 tdep->gregset = regset_alloc (gdbarch, amd64obsd_supply_regset, NULL); 71 return tdep->gregset; 72 } 73 74 return NULL; 75 } 76 77 78 /* Support for signal handlers. */ 79 80 /* Default page size. */ 81 static const int amd64obsd_page_size = 4096; 82 83 /* Return whether the frame preceding NEXT_FRAME corresponds to an 84 OpenBSD sigtramp routine. */ 85 86 static int 87 amd64obsd_sigtramp_p (struct frame_info *next_frame) 88 { 89 CORE_ADDR pc = frame_pc_unwind (next_frame); 90 CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1)); 91 const char sigreturn[] = 92 { 93 0x48, 0xc7, 0xc0, 94 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */ 95 0xcd, 0x80 /* int $0x80 */ 96 }; 97 size_t buflen = (sizeof sigreturn) + 1; 98 char *name, *buf; 99 100 /* If the function has a valid symbol name, it isn't a 101 trampoline. */ 102 find_pc_partial_function (pc, &name, NULL, NULL); 103 if (name != NULL) 104 return 0; 105 106 /* If the function lives in a valid section (even without a starting 107 point) it isn't a trampoline. */ 108 if (find_pc_section (pc) != NULL) 109 return 0; 110 111 /* If we can't read the instructions at START_PC, return zero. */ 112 buf = alloca ((sizeof sigreturn) + 1); 113 if (!safe_frame_unwind_memory (next_frame, start_pc + 6, buf, buflen)) 114 return 0; 115 116 /* Check for sigreturn(2). Depending on how the assembler encoded 117 the `movq %rsp, %rdi' instruction, the code starts at offset 6 or 118 7. */ 119 if (memcmp (buf, sigreturn, sizeof sigreturn) 120 && memcpy (buf + 1, sigreturn, sizeof sigreturn)) 121 return 0; 122 123 return 1; 124 } 125 126 /* Assuming NEXT_FRAME is for a frame following a BSD sigtramp 127 routine, return the address of the associated sigcontext structure. */ 128 129 static CORE_ADDR 130 amd64obsd_sigcontext_addr (struct frame_info *next_frame) 131 { 132 CORE_ADDR pc = frame_pc_unwind (next_frame); 133 ULONGEST offset = (pc & (amd64obsd_page_size - 1)); 134 135 /* The %rsp register points at `struct sigcontext' upon entry of a 136 signal trampoline. The relevant part of the trampoline is 137 138 call *%rax 139 movq %rsp, %rdi 140 pushq %rdi 141 movq $SYS_sigreturn,%rax 142 int $0x80 143 144 (see /usr/src/sys/arch/amd64/amd64/locore.S). The `pushq' 145 instruction clobbers %rsp, but its value is saved in `%rdi'. */ 146 147 if (offset > 5) 148 return frame_unwind_register_unsigned (next_frame, AMD64_RDI_REGNUM); 149 else 150 return frame_unwind_register_unsigned (next_frame, AMD64_RSP_REGNUM); 151 } 152 153 /* OpenBSD 3.5 or later. */ 154 155 /* Mapping between the general-purpose registers in `struct reg' 156 format and GDB's register cache layout. */ 157 158 /* From <machine/reg.h>. */ 159 int amd64obsd_r_reg_offset[] = 160 { 161 14 * 8, /* %rax */ 162 13 * 8, /* %rbx */ 163 3 * 8, /* %rcx */ 164 2 * 8, /* %rdx */ 165 1 * 8, /* %rsi */ 166 0 * 8, /* %rdi */ 167 12 * 8, /* %rbp */ 168 15 * 8, /* %rsp */ 169 4 * 8, /* %r8 .. */ 170 5 * 8, 171 6 * 8, 172 7 * 8, 173 8 * 8, 174 9 * 8, 175 10 * 8, 176 11 * 8, /* ... %r15 */ 177 16 * 8, /* %rip */ 178 17 * 8, /* %eflags */ 179 18 * 8, /* %cs */ 180 19 * 8, /* %ss */ 181 20 * 8, /* %ds */ 182 21 * 8, /* %es */ 183 22 * 8, /* %fs */ 184 23 * 8 /* %gs */ 185 }; 186 187 /* From <machine/signal.h>. */ 188 static int amd64obsd_sc_reg_offset[] = 189 { 190 14 * 8, /* %rax */ 191 13 * 8, /* %rbx */ 192 3 * 8, /* %rcx */ 193 2 * 8, /* %rdx */ 194 1 * 8, /* %rsi */ 195 0 * 8, /* %rdi */ 196 12 * 8, /* %rbp */ 197 24 * 8, /* %rsp */ 198 4 * 8, /* %r8 ... */ 199 5 * 8, 200 6 * 8, 201 7 * 8, 202 8 * 8, 203 9 * 8, 204 10 * 8, 205 11 * 8, /* ... %r15 */ 206 21 * 8, /* %rip */ 207 23 * 8, /* %eflags */ 208 22 * 8, /* %cs */ 209 25 * 8, /* %ss */ 210 18 * 8, /* %ds */ 211 17 * 8, /* %es */ 212 16 * 8, /* %fs */ 213 15 * 8 /* %gs */ 214 }; 215 216 /* From /usr/src/lib/libpthread/arch/amd64/uthread_machdep.c. */ 217 static int amd64obsd_uthread_reg_offset[] = 218 { 219 19 * 8, /* %rax */ 220 16 * 8, /* %rbx */ 221 18 * 8, /* %rcx */ 222 17 * 8, /* %rdx */ 223 14 * 8, /* %rsi */ 224 13 * 8, /* %rdi */ 225 15 * 8, /* %rbp */ 226 -1, /* %rsp */ 227 12 * 8, /* %r8 ... */ 228 11 * 8, 229 10 * 8, 230 9 * 8, 231 8 * 8, 232 7 * 8, 233 6 * 8, 234 5 * 8, /* ... %r15 */ 235 20 * 8, /* %rip */ 236 4 * 8, /* %eflags */ 237 21 * 8, /* %cs */ 238 -1, /* %ss */ 239 3 * 8, /* %ds */ 240 2 * 8, /* %es */ 241 1 * 8, /* %fs */ 242 0 * 8 /* %gs */ 243 }; 244 245 /* Offset within the thread structure where we can find the saved 246 stack pointer (%esp). */ 247 #define AMD64OBSD_UTHREAD_RSP_OFFSET 400 248 249 static void 250 amd64obsd_supply_uthread (struct regcache *regcache, 251 int regnum, CORE_ADDR addr) 252 { 253 CORE_ADDR sp_addr = addr + AMD64OBSD_UTHREAD_RSP_OFFSET; 254 CORE_ADDR sp = 0; 255 char buf[8]; 256 int i; 257 258 gdb_assert (regnum >= -1); 259 260 if (regnum == -1 || regnum == AMD64_RSP_REGNUM) 261 { 262 int offset; 263 264 /* Fetch stack pointer from thread structure. */ 265 sp = read_memory_unsigned_integer (sp_addr, 8); 266 267 /* Adjust the stack pointer such that it looks as if we just 268 returned from _thread_machdep_switch. */ 269 offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8; 270 store_unsigned_integer (buf, 8, sp + offset); 271 regcache_raw_supply (regcache, AMD64_RSP_REGNUM, buf); 272 } 273 274 for (i = 0; i < ARRAY_SIZE (amd64obsd_uthread_reg_offset); i++) 275 { 276 if (amd64obsd_uthread_reg_offset[i] != -1 277 && (regnum == -1 || regnum == i)) 278 { 279 /* Fetch stack pointer from thread structure (if we didn't 280 do so already). */ 281 if (sp == 0) 282 sp = read_memory_unsigned_integer (sp_addr, 8); 283 284 /* Read the saved register from the stack frame. */ 285 read_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8); 286 regcache_raw_supply (regcache, i, buf); 287 } 288 } 289 } 290 291 static void 292 amd64obsd_collect_uthread (const struct regcache *regcache, 293 int regnum, CORE_ADDR addr) 294 { 295 CORE_ADDR sp_addr = addr + AMD64OBSD_UTHREAD_RSP_OFFSET; 296 CORE_ADDR sp = 0; 297 char buf[8]; 298 int i; 299 300 gdb_assert (regnum >= -1); 301 302 if (regnum == -1 || regnum == AMD64_RSP_REGNUM) 303 { 304 int offset; 305 306 /* Calculate the stack pointer (frame pointer) that will be 307 stored into the thread structure. */ 308 offset = amd64obsd_uthread_reg_offset[AMD64_RIP_REGNUM] + 8; 309 regcache_raw_collect (regcache, AMD64_RSP_REGNUM, buf); 310 sp = extract_unsigned_integer (buf, 8) - offset; 311 312 /* Store the stack pointer. */ 313 write_memory_unsigned_integer (sp_addr, 8, sp); 314 315 /* The stack pointer was (potentially) modified. Make sure we 316 build a proper stack frame. */ 317 regnum = -1; 318 } 319 320 for (i = 0; i < ARRAY_SIZE (amd64obsd_uthread_reg_offset); i++) 321 { 322 if (amd64obsd_uthread_reg_offset[i] != -1 323 && (regnum == -1 || regnum == i)) 324 { 325 /* Fetch stack pointer from thread structure (if we didn't 326 calculate it already). */ 327 if (sp == 0) 328 sp = read_memory_unsigned_integer (sp_addr, 8); 329 330 /* Write the register into the stack frame. */ 331 regcache_raw_collect (regcache, i, buf); 332 write_memory (sp + amd64obsd_uthread_reg_offset[i], buf, 8); 333 } 334 } 335 } 336 337 338 /* Kernel debugging support. */ 339 340 /* From <machine/frame.h>. Easy since `struct trapframe' matches 341 `struct sigcontext'. */ 342 #define amd64obsd_tf_reg_offset amd64obsd_sc_reg_offset 343 344 static struct trad_frame_cache * 345 amd64obsd_trapframe_cache(struct frame_info *next_frame, void **this_cache) 346 { 347 struct trad_frame_cache *cache; 348 CORE_ADDR func, sp, addr; 349 ULONGEST cs; 350 char *name; 351 int i; 352 353 if (*this_cache) 354 return *this_cache; 355 356 cache = trad_frame_cache_zalloc (next_frame); 357 *this_cache = cache; 358 359 func = frame_func_unwind (next_frame); 360 sp = frame_unwind_register_unsigned (next_frame, AMD64_RSP_REGNUM); 361 362 find_pc_partial_function (func, &name, NULL, NULL); 363 if (name && strncmp(name, "Xintr", 5) == 0) 364 addr = sp + 8; /* It's an interrupt frame. */ 365 else 366 addr = sp; 367 368 for (i = 0; i < ARRAY_SIZE (amd64obsd_tf_reg_offset); i++) 369 if (amd64obsd_tf_reg_offset[i] != -1) 370 trad_frame_set_reg_addr (cache, i, addr + amd64obsd_tf_reg_offset[i]); 371 372 /* Read %cs from trap frame. */ 373 addr += amd64obsd_tf_reg_offset[AMD64_CS_REGNUM]; 374 cs = read_memory_unsigned_integer (addr, 8); 375 if ((cs & I386_SEL_RPL) == I386_SEL_UPL) 376 { 377 /* Trap from use space; terminate backtrace. */ 378 trad_frame_set_id (cache, null_frame_id); 379 } 380 else 381 { 382 /* Construct the frame ID using the function start. */ 383 trad_frame_set_id (cache, frame_id_build (sp + 16, func)); 384 } 385 386 return cache; 387 } 388 389 static void 390 amd64obsd_trapframe_this_id (struct frame_info *next_frame, 391 void **this_cache, struct frame_id *this_id) 392 { 393 struct trad_frame_cache *cache = 394 amd64obsd_trapframe_cache (next_frame, this_cache); 395 396 trad_frame_get_id (cache, this_id); 397 } 398 399 static void 400 amd64obsd_trapframe_prev_register (struct frame_info *next_frame, 401 void **this_cache, int regnum, 402 int *optimizedp, enum lval_type *lvalp, 403 CORE_ADDR *addrp, int *realnump, 404 void *valuep) 405 { 406 struct trad_frame_cache *cache = 407 amd64obsd_trapframe_cache (next_frame, this_cache); 408 409 trad_frame_get_register (cache, next_frame, regnum, 410 optimizedp, lvalp, addrp, realnump, valuep); 411 } 412 413 static int 414 amd64obsd_trapframe_sniffer (const struct frame_unwind *self, 415 struct frame_info *next_frame, 416 void **this_prologue_cache) 417 { 418 ULONGEST cs; 419 char *name; 420 421 cs = frame_unwind_register_unsigned (next_frame, AMD64_CS_REGNUM); 422 if ((cs & I386_SEL_RPL) == I386_SEL_UPL) 423 return 0; 424 425 find_pc_partial_function (frame_pc_unwind (next_frame), &name, NULL, NULL); 426 return (name && ((strcmp (name, "calltrap") == 0) 427 || (strcmp (name, "osyscall1") == 0) 428 || (strcmp (name, "Xsyscall") == 0) 429 || (strncmp (name, "Xintr", 5) == 0))); 430 } 431 432 static const struct frame_unwind amd64obsd_trapframe_unwind = { 433 /* FIXME: kettenis/20051219: This really is more like an interrupt 434 frame, but SIGTRAMP_FRAME would print <signal handler called>, 435 which really is not what we want here. */ 436 NORMAL_FRAME, 437 amd64obsd_trapframe_this_id, 438 amd64obsd_trapframe_prev_register, 439 NULL, 440 amd64obsd_trapframe_sniffer 441 }; 442 443 444 static void 445 amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 446 { 447 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 448 449 amd64_init_abi (info, gdbarch); 450 451 /* Initialize general-purpose register set details. */ 452 tdep->gregset_reg_offset = amd64obsd_r_reg_offset; 453 tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset); 454 tdep->sizeof_gregset = 24 * 8; 455 456 tdep->jb_pc_offset = 7 * 8; 457 458 tdep->sigtramp_p = amd64obsd_sigtramp_p; 459 tdep->sigcontext_addr = amd64obsd_sigcontext_addr; 460 tdep->sc_reg_offset = amd64obsd_sc_reg_offset; 461 tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset); 462 463 /* OpenBSD provides a user-level threads implementation. */ 464 bsd_uthread_set_supply_uthread (gdbarch, amd64obsd_supply_uthread); 465 bsd_uthread_set_collect_uthread (gdbarch, amd64obsd_collect_uthread); 466 467 /* OpenBSD uses SVR4-style shared libraries. */ 468 set_solib_svr4_fetch_link_map_offsets 469 (gdbarch, svr4_lp64_fetch_link_map_offsets); 470 471 /* Unwind kernel trap frames correctly. */ 472 frame_unwind_prepend_unwinder (gdbarch, &amd64obsd_trapframe_unwind); 473 } 474 475 /* Traditional (a.out) NetBSD-style core dumps. */ 476 477 static void 478 amd64obsd_core_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 479 { 480 amd64obsd_init_abi (info, gdbarch); 481 482 set_gdbarch_regset_from_core_section 483 (gdbarch, amd64obsd_regset_from_core_section); 484 } 485 486 487 /* Provide a prototype to silence -Wmissing-prototypes. */ 488 void _initialize_amd64obsd_tdep (void); 489 490 void 491 _initialize_amd64obsd_tdep (void) 492 { 493 /* The OpenBSD/amd64 native dependent code makes this assumption. */ 494 gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == AMD64_NUM_GREGS); 495 496 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, 497 GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi); 498 499 /* OpenBSD uses traditional (a.out) NetBSD-style core dumps. */ 500 gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, 501 GDB_OSABI_NETBSD_AOUT, amd64obsd_core_init_abi); 502 } 503