| 1 | /* Target-dependent code for GNU/Linux running on i386's, for GDB. |
| 2 | |
| 3 | Copyright 2000, 2001, 2002 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 "gdbcore.h" |
| 24 | #include "frame.h" |
| 25 | #include "value.h" |
| 26 | #include "regcache.h" |
| 27 | #include "inferior.h" |
| 28 | |
| 29 | /* For i386_linux_skip_solib_resolver. */ |
| 30 | #include "symtab.h" |
| 31 | #include "symfile.h" |
| 32 | #include "objfiles.h" |
| 33 | |
| 34 | #include "solib-svr4.h" /* For struct link_map_offsets. */ |
| 35 | |
| 36 | #include "i386-tdep.h" |
| 37 | #include "i386-linux-tdep.h" |
| 38 | |
| 39 | /* Return the name of register REG. */ |
| 40 | |
| 41 | static const char * |
| 42 | i386_linux_register_name (int reg) |
| 43 | { |
| 44 | /* Deal with the extra "orig_eax" pseudo register. */ |
| 45 | if (reg == I386_LINUX_ORIG_EAX_REGNUM) |
| 46 | return "orig_eax"; |
| 47 | |
| 48 | return i386_register_name (reg); |
| 49 | } |
| 50 | |
| 51 | static int |
| 52 | i386_linux_register_byte (int reg) |
| 53 | { |
| 54 | /* Deal with the extra "orig_eax" pseudo register. */ |
| 55 | if (reg == I386_LINUX_ORIG_EAX_REGNUM) |
| 56 | return (i386_register_byte (I386_LINUX_ORIG_EAX_REGNUM - 1) |
| 57 | + i386_register_raw_size (I386_LINUX_ORIG_EAX_REGNUM - 1)); |
| 58 | |
| 59 | return i386_register_byte (reg); |
| 60 | } |
| 61 | |
| 62 | static int |
| 63 | i386_linux_register_raw_size (int reg) |
| 64 | { |
| 65 | /* Deal with the extra "orig_eax" pseudo register. */ |
| 66 | if (reg == I386_LINUX_ORIG_EAX_REGNUM) |
| 67 | return 4; |
| 68 | |
| 69 | return i386_register_raw_size (reg); |
| 70 | } |
| 71 | \f |
| 72 | /* Recognizing signal handler frames. */ |
| 73 | |
| 74 | /* GNU/Linux has two flavors of signals. Normal signal handlers, and |
| 75 | "realtime" (RT) signals. The RT signals can provide additional |
| 76 | information to the signal handler if the SA_SIGINFO flag is set |
| 77 | when establishing a signal handler using `sigaction'. It is not |
| 78 | unlikely that future versions of GNU/Linux will support SA_SIGINFO |
| 79 | for normal signals too. */ |
| 80 | |
| 81 | /* When the i386 Linux kernel calls a signal handler and the |
| 82 | SA_RESTORER flag isn't set, the return address points to a bit of |
| 83 | code on the stack. This function returns whether the PC appears to |
| 84 | be within this bit of code. |
| 85 | |
| 86 | The instruction sequence for normal signals is |
| 87 | pop %eax |
| 88 | mov $0x77,%eax |
| 89 | int $0x80 |
| 90 | or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80. |
| 91 | |
| 92 | Checking for the code sequence should be somewhat reliable, because |
| 93 | the effect is to call the system call sigreturn. This is unlikely |
| 94 | to occur anywhere other than a signal trampoline. |
| 95 | |
| 96 | It kind of sucks that we have to read memory from the process in |
| 97 | order to identify a signal trampoline, but there doesn't seem to be |
| 98 | any other way. The PC_IN_SIGTRAMP macro in tm-linux.h arranges to |
| 99 | only call us if no function name could be identified, which should |
| 100 | be the case since the code is on the stack. |
| 101 | |
| 102 | Detection of signal trampolines for handlers that set the |
| 103 | SA_RESTORER flag is in general not possible. Unfortunately this is |
| 104 | what the GNU C Library has been doing for quite some time now. |
| 105 | However, as of version 2.1.2, the GNU C Library uses signal |
| 106 | trampolines (named __restore and __restore_rt) that are identical |
| 107 | to the ones used by the kernel. Therefore, these trampolines are |
| 108 | supported too. */ |
| 109 | |
| 110 | #define LINUX_SIGTRAMP_INSN0 (0x58) /* pop %eax */ |
| 111 | #define LINUX_SIGTRAMP_OFFSET0 (0) |
| 112 | #define LINUX_SIGTRAMP_INSN1 (0xb8) /* mov $NNNN,%eax */ |
| 113 | #define LINUX_SIGTRAMP_OFFSET1 (1) |
| 114 | #define LINUX_SIGTRAMP_INSN2 (0xcd) /* int */ |
| 115 | #define LINUX_SIGTRAMP_OFFSET2 (6) |
| 116 | |
| 117 | static const unsigned char linux_sigtramp_code[] = |
| 118 | { |
| 119 | LINUX_SIGTRAMP_INSN0, /* pop %eax */ |
| 120 | LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77,%eax */ |
| 121 | LINUX_SIGTRAMP_INSN2, 0x80 /* int $0x80 */ |
| 122 | }; |
| 123 | |
| 124 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) |
| 125 | |
| 126 | /* If PC is in a sigtramp routine, return the address of the start of |
| 127 | the routine. Otherwise, return 0. */ |
| 128 | |
| 129 | static CORE_ADDR |
| 130 | i386_linux_sigtramp_start (CORE_ADDR pc) |
| 131 | { |
| 132 | unsigned char buf[LINUX_SIGTRAMP_LEN]; |
| 133 | |
| 134 | /* We only recognize a signal trampoline if PC is at the start of |
| 135 | one of the three instructions. We optimize for finding the PC at |
| 136 | the start, as will be the case when the trampoline is not the |
| 137 | first frame on the stack. We assume that in the case where the |
| 138 | PC is not at the start of the instruction sequence, there will be |
| 139 | a few trailing readable bytes on the stack. */ |
| 140 | |
| 141 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 142 | return 0; |
| 143 | |
| 144 | if (buf[0] != LINUX_SIGTRAMP_INSN0) |
| 145 | { |
| 146 | int adjust; |
| 147 | |
| 148 | switch (buf[0]) |
| 149 | { |
| 150 | case LINUX_SIGTRAMP_INSN1: |
| 151 | adjust = LINUX_SIGTRAMP_OFFSET1; |
| 152 | break; |
| 153 | case LINUX_SIGTRAMP_INSN2: |
| 154 | adjust = LINUX_SIGTRAMP_OFFSET2; |
| 155 | break; |
| 156 | default: |
| 157 | return 0; |
| 158 | } |
| 159 | |
| 160 | pc -= adjust; |
| 161 | |
| 162 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 163 | return 0; |
| 164 | } |
| 165 | |
| 166 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) |
| 167 | return 0; |
| 168 | |
| 169 | return pc; |
| 170 | } |
| 171 | |
| 172 | /* This function does the same for RT signals. Here the instruction |
| 173 | sequence is |
| 174 | mov $0xad,%eax |
| 175 | int $0x80 |
| 176 | or 0xb8 0xad 0x00 0x00 0x00 0xcd 0x80. |
| 177 | |
| 178 | The effect is to call the system call rt_sigreturn. */ |
| 179 | |
| 180 | #define LINUX_RT_SIGTRAMP_INSN0 (0xb8) /* mov $NNNN,%eax */ |
| 181 | #define LINUX_RT_SIGTRAMP_OFFSET0 (0) |
| 182 | #define LINUX_RT_SIGTRAMP_INSN1 (0xcd) /* int */ |
| 183 | #define LINUX_RT_SIGTRAMP_OFFSET1 (5) |
| 184 | |
| 185 | static const unsigned char linux_rt_sigtramp_code[] = |
| 186 | { |
| 187 | LINUX_RT_SIGTRAMP_INSN0, 0xad, 0x00, 0x00, 0x00, /* mov $0xad,%eax */ |
| 188 | LINUX_RT_SIGTRAMP_INSN1, 0x80 /* int $0x80 */ |
| 189 | }; |
| 190 | |
| 191 | #define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code) |
| 192 | |
| 193 | /* If PC is in a RT sigtramp routine, return the address of the start |
| 194 | of the routine. Otherwise, return 0. */ |
| 195 | |
| 196 | static CORE_ADDR |
| 197 | i386_linux_rt_sigtramp_start (CORE_ADDR pc) |
| 198 | { |
| 199 | unsigned char buf[LINUX_RT_SIGTRAMP_LEN]; |
| 200 | |
| 201 | /* We only recognize a signal trampoline if PC is at the start of |
| 202 | one of the two instructions. We optimize for finding the PC at |
| 203 | the start, as will be the case when the trampoline is not the |
| 204 | first frame on the stack. We assume that in the case where the |
| 205 | PC is not at the start of the instruction sequence, there will be |
| 206 | a few trailing readable bytes on the stack. */ |
| 207 | |
| 208 | if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) |
| 209 | return 0; |
| 210 | |
| 211 | if (buf[0] != LINUX_RT_SIGTRAMP_INSN0) |
| 212 | { |
| 213 | if (buf[0] != LINUX_RT_SIGTRAMP_INSN1) |
| 214 | return 0; |
| 215 | |
| 216 | pc -= LINUX_RT_SIGTRAMP_OFFSET1; |
| 217 | |
| 218 | if (read_memory_nobpt (pc, (char *) buf, LINUX_RT_SIGTRAMP_LEN) != 0) |
| 219 | return 0; |
| 220 | } |
| 221 | |
| 222 | if (memcmp (buf, linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN) != 0) |
| 223 | return 0; |
| 224 | |
| 225 | return pc; |
| 226 | } |
| 227 | |
| 228 | /* Return whether PC is in a GNU/Linux sigtramp routine. */ |
| 229 | |
| 230 | static int |
| 231 | i386_linux_pc_in_sigtramp (CORE_ADDR pc, char *name) |
| 232 | { |
| 233 | if (name) |
| 234 | return STREQ ("__restore", name) || STREQ ("__restore_rt", name); |
| 235 | |
| 236 | return (i386_linux_sigtramp_start (pc) != 0 |
| 237 | || i386_linux_rt_sigtramp_start (pc) != 0); |
| 238 | } |
| 239 | |
| 240 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
| 241 | address of the associated sigcontext structure. */ |
| 242 | |
| 243 | CORE_ADDR |
| 244 | i386_linux_sigcontext_addr (struct frame_info *frame) |
| 245 | { |
| 246 | CORE_ADDR pc; |
| 247 | |
| 248 | pc = i386_linux_sigtramp_start (frame->pc); |
| 249 | if (pc) |
| 250 | { |
| 251 | CORE_ADDR sp; |
| 252 | |
| 253 | if (frame->next) |
| 254 | /* If this isn't the top frame, the next frame must be for the |
| 255 | signal handler itself. The sigcontext structure lives on |
| 256 | the stack, right after the signum argument. */ |
| 257 | return frame->next->frame + 12; |
| 258 | |
| 259 | /* This is the top frame. We'll have to find the address of the |
| 260 | sigcontext structure by looking at the stack pointer. Keep |
| 261 | in mind that the first instruction of the sigtramp code is |
| 262 | "pop %eax". If the PC is at this instruction, adjust the |
| 263 | returned value accordingly. */ |
| 264 | sp = read_register (SP_REGNUM); |
| 265 | if (pc == frame->pc) |
| 266 | return sp + 4; |
| 267 | return sp; |
| 268 | } |
| 269 | |
| 270 | pc = i386_linux_rt_sigtramp_start (frame->pc); |
| 271 | if (pc) |
| 272 | { |
| 273 | if (frame->next) |
| 274 | /* If this isn't the top frame, the next frame must be for the |
| 275 | signal handler itself. The sigcontext structure is part of |
| 276 | the user context. A pointer to the user context is passed |
| 277 | as the third argument to the signal handler. */ |
| 278 | return read_memory_integer (frame->next->frame + 16, 4) + 20; |
| 279 | |
| 280 | /* This is the top frame. Again, use the stack pointer to find |
| 281 | the address of the sigcontext structure. */ |
| 282 | return read_memory_integer (read_register (SP_REGNUM) + 8, 4) + 20; |
| 283 | } |
| 284 | |
| 285 | error ("Couldn't recognize signal trampoline."); |
| 286 | return 0; |
| 287 | } |
| 288 | |
| 289 | /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ |
| 290 | #define LINUX_SIGCONTEXT_PC_OFFSET (56) |
| 291 | |
| 292 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
| 293 | saved program counter. */ |
| 294 | |
| 295 | static CORE_ADDR |
| 296 | i386_linux_sigtramp_saved_pc (struct frame_info *frame) |
| 297 | { |
| 298 | CORE_ADDR addr; |
| 299 | addr = i386_linux_sigcontext_addr (frame); |
| 300 | return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 4); |
| 301 | } |
| 302 | |
| 303 | /* Offset to saved SP in sigcontext, from <asm/sigcontext.h>. */ |
| 304 | #define LINUX_SIGCONTEXT_SP_OFFSET (28) |
| 305 | |
| 306 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
| 307 | saved stack pointer. */ |
| 308 | |
| 309 | static CORE_ADDR |
| 310 | i386_linux_sigtramp_saved_sp (struct frame_info *frame) |
| 311 | { |
| 312 | CORE_ADDR addr; |
| 313 | addr = i386_linux_sigcontext_addr (frame); |
| 314 | return read_memory_integer (addr + LINUX_SIGCONTEXT_SP_OFFSET, 4); |
| 315 | } |
| 316 | |
| 317 | /* Signal trampolines don't have a meaningful frame. As in |
| 318 | "i386/tm-i386.h", the frame pointer value we use is actually the |
| 319 | frame pointer of the calling frame -- that is, the frame which was |
| 320 | in progress when the signal trampoline was entered. GDB mostly |
| 321 | treats this frame pointer value as a magic cookie. We detect the |
| 322 | case of a signal trampoline by looking at the SIGNAL_HANDLER_CALLER |
| 323 | field, which is set based on PC_IN_SIGTRAMP. |
| 324 | |
| 325 | When a signal trampoline is invoked from a frameless function, we |
| 326 | essentially have two frameless functions in a row. In this case, |
| 327 | we use the same magic cookie for three frames in a row. We detect |
| 328 | this case by seeing whether the next frame has |
| 329 | SIGNAL_HANDLER_CALLER set, and, if it does, checking whether the |
| 330 | current frame is actually frameless. In this case, we need to get |
| 331 | the PC by looking at the SP register value stored in the signal |
| 332 | context. |
| 333 | |
| 334 | This should work in most cases except in horrible situations where |
| 335 | a signal occurs just as we enter a function but before the frame |
| 336 | has been set up. */ |
| 337 | |
| 338 | #define FRAMELESS_SIGNAL(frame) \ |
| 339 | ((frame)->next != NULL \ |
| 340 | && (frame)->next->signal_handler_caller \ |
| 341 | && frameless_look_for_prologue (frame)) |
| 342 | |
| 343 | CORE_ADDR |
| 344 | i386_linux_frame_chain (struct frame_info *frame) |
| 345 | { |
| 346 | if (frame->signal_handler_caller || FRAMELESS_SIGNAL (frame)) |
| 347 | return frame->frame; |
| 348 | |
| 349 | if (! inside_entry_file (frame->pc)) |
| 350 | return read_memory_unsigned_integer (frame->frame, 4); |
| 351 | |
| 352 | return 0; |
| 353 | } |
| 354 | |
| 355 | /* Return the saved program counter for FRAME. */ |
| 356 | |
| 357 | CORE_ADDR |
| 358 | i386_linux_frame_saved_pc (struct frame_info *frame) |
| 359 | { |
| 360 | if (frame->signal_handler_caller) |
| 361 | return i386_linux_sigtramp_saved_pc (frame); |
| 362 | |
| 363 | if (FRAMELESS_SIGNAL (frame)) |
| 364 | { |
| 365 | CORE_ADDR sp = i386_linux_sigtramp_saved_sp (frame->next); |
| 366 | return read_memory_unsigned_integer (sp, 4); |
| 367 | } |
| 368 | |
| 369 | return read_memory_unsigned_integer (frame->frame + 4, 4); |
| 370 | } |
| 371 | |
| 372 | /* Immediately after a function call, return the saved pc. */ |
| 373 | |
| 374 | CORE_ADDR |
| 375 | i386_linux_saved_pc_after_call (struct frame_info *frame) |
| 376 | { |
| 377 | if (frame->signal_handler_caller) |
| 378 | return i386_linux_sigtramp_saved_pc (frame); |
| 379 | |
| 380 | return read_memory_unsigned_integer (read_register (SP_REGNUM), 4); |
| 381 | } |
| 382 | |
| 383 | /* Set the program counter for process PTID to PC. */ |
| 384 | |
| 385 | static void |
| 386 | i386_linux_write_pc (CORE_ADDR pc, ptid_t ptid) |
| 387 | { |
| 388 | write_register_pid (PC_REGNUM, pc, ptid); |
| 389 | |
| 390 | /* We must be careful with modifying the program counter. If we |
| 391 | just interrupted a system call, the kernel might try to restart |
| 392 | it when we resume the inferior. On restarting the system call, |
| 393 | the kernel will try backing up the program counter even though it |
| 394 | no longer points at the system call. This typically results in a |
| 395 | SIGSEGV or SIGILL. We can prevent this by writing `-1' in the |
| 396 | "orig_eax" pseudo-register. |
| 397 | |
| 398 | Note that "orig_eax" is saved when setting up a dummy call frame. |
| 399 | This means that it is properly restored when that frame is |
| 400 | popped, and that the interrupted system call will be restarted |
| 401 | when we resume the inferior on return from a function call from |
| 402 | within GDB. In all other cases the system call will not be |
| 403 | restarted. */ |
| 404 | write_register_pid (I386_LINUX_ORIG_EAX_REGNUM, -1, ptid); |
| 405 | } |
| 406 | \f |
| 407 | /* Calling functions in shared libraries. */ |
| 408 | |
| 409 | /* Find the minimal symbol named NAME, and return both the minsym |
| 410 | struct and its objfile. This probably ought to be in minsym.c, but |
| 411 | everything there is trying to deal with things like C++ and |
| 412 | SOFUN_ADDRESS_MAYBE_TURQUOISE, ... Since this is so simple, it may |
| 413 | be considered too special-purpose for general consumption. */ |
| 414 | |
| 415 | static struct minimal_symbol * |
| 416 | find_minsym_and_objfile (char *name, struct objfile **objfile_p) |
| 417 | { |
| 418 | struct objfile *objfile; |
| 419 | |
| 420 | ALL_OBJFILES (objfile) |
| 421 | { |
| 422 | struct minimal_symbol *msym; |
| 423 | |
| 424 | ALL_OBJFILE_MSYMBOLS (objfile, msym) |
| 425 | { |
| 426 | if (SYMBOL_NAME (msym) |
| 427 | && STREQ (SYMBOL_NAME (msym), name)) |
| 428 | { |
| 429 | *objfile_p = objfile; |
| 430 | return msym; |
| 431 | } |
| 432 | } |
| 433 | } |
| 434 | |
| 435 | return 0; |
| 436 | } |
| 437 | |
| 438 | static CORE_ADDR |
| 439 | skip_hurd_resolver (CORE_ADDR pc) |
| 440 | { |
| 441 | /* The HURD dynamic linker is part of the GNU C library, so many |
| 442 | GNU/Linux distributions use it. (All ELF versions, as far as I |
| 443 | know.) An unresolved PLT entry points to "_dl_runtime_resolve", |
| 444 | which calls "fixup" to patch the PLT, and then passes control to |
| 445 | the function. |
| 446 | |
| 447 | We look for the symbol `_dl_runtime_resolve', and find `fixup' in |
| 448 | the same objfile. If we are at the entry point of `fixup', then |
| 449 | we set a breakpoint at the return address (at the top of the |
| 450 | stack), and continue. |
| 451 | |
| 452 | It's kind of gross to do all these checks every time we're |
| 453 | called, since they don't change once the executable has gotten |
| 454 | started. But this is only a temporary hack --- upcoming versions |
| 455 | of GNU/Linux will provide a portable, efficient interface for |
| 456 | debugging programs that use shared libraries. */ |
| 457 | |
| 458 | struct objfile *objfile; |
| 459 | struct minimal_symbol *resolver |
| 460 | = find_minsym_and_objfile ("_dl_runtime_resolve", &objfile); |
| 461 | |
| 462 | if (resolver) |
| 463 | { |
| 464 | struct minimal_symbol *fixup |
| 465 | = lookup_minimal_symbol ("fixup", NULL, objfile); |
| 466 | |
| 467 | if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc) |
| 468 | return (SAVED_PC_AFTER_CALL (get_current_frame ())); |
| 469 | } |
| 470 | |
| 471 | return 0; |
| 472 | } |
| 473 | |
| 474 | /* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c. |
| 475 | This function: |
| 476 | 1) decides whether a PLT has sent us into the linker to resolve |
| 477 | a function reference, and |
| 478 | 2) if so, tells us where to set a temporary breakpoint that will |
| 479 | trigger when the dynamic linker is done. */ |
| 480 | |
| 481 | CORE_ADDR |
| 482 | i386_linux_skip_solib_resolver (CORE_ADDR pc) |
| 483 | { |
| 484 | CORE_ADDR result; |
| 485 | |
| 486 | /* Plug in functions for other kinds of resolvers here. */ |
| 487 | result = skip_hurd_resolver (pc); |
| 488 | if (result) |
| 489 | return result; |
| 490 | |
| 491 | return 0; |
| 492 | } |
| 493 | |
| 494 | /* Fetch (and possibly build) an appropriate link_map_offsets |
| 495 | structure for native GNU/Linux x86 targets using the struct offsets |
| 496 | defined in link.h (but without actual reference to that file). |
| 497 | |
| 498 | This makes it possible to access GNU/Linux x86 shared libraries |
| 499 | from a GDB that was not built on an GNU/Linux x86 host (for cross |
| 500 | debugging). */ |
| 501 | |
| 502 | static struct link_map_offsets * |
| 503 | i386_linux_svr4_fetch_link_map_offsets (void) |
| 504 | { |
| 505 | static struct link_map_offsets lmo; |
| 506 | static struct link_map_offsets *lmp = NULL; |
| 507 | |
| 508 | if (lmp == NULL) |
| 509 | { |
| 510 | lmp = &lmo; |
| 511 | |
| 512 | lmo.r_debug_size = 8; /* The actual size is 20 bytes, but |
| 513 | this is all we need. */ |
| 514 | lmo.r_map_offset = 4; |
| 515 | lmo.r_map_size = 4; |
| 516 | |
| 517 | lmo.link_map_size = 20; /* The actual size is 552 bytes, but |
| 518 | this is all we need. */ |
| 519 | lmo.l_addr_offset = 0; |
| 520 | lmo.l_addr_size = 4; |
| 521 | |
| 522 | lmo.l_name_offset = 4; |
| 523 | lmo.l_name_size = 4; |
| 524 | |
| 525 | lmo.l_next_offset = 12; |
| 526 | lmo.l_next_size = 4; |
| 527 | |
| 528 | lmo.l_prev_offset = 16; |
| 529 | lmo.l_prev_size = 4; |
| 530 | } |
| 531 | |
| 532 | return lmp; |
| 533 | } |
| 534 | \f |
| 535 | |
| 536 | static void |
| 537 | i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 538 | { |
| 539 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 540 | |
| 541 | /* GNU/Linux uses ELF. */ |
| 542 | i386_elf_init_abi (info, gdbarch); |
| 543 | |
| 544 | /* We support the SSE registers on GNU/Linux. */ |
| 545 | tdep->num_xmm_regs = I386_NUM_XREGS - 1; |
| 546 | /* set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS); */ |
| 547 | |
| 548 | /* Since we have the extra "orig_eax" register on GNU/Linux, we have |
| 549 | to adjust a few things. */ |
| 550 | |
| 551 | set_gdbarch_write_pc (gdbarch, i386_linux_write_pc); |
| 552 | set_gdbarch_num_regs (gdbarch, I386_SSE_NUM_REGS + 1); |
| 553 | set_gdbarch_register_name (gdbarch, i386_linux_register_name); |
| 554 | set_gdbarch_register_bytes (gdbarch, I386_SSE_SIZEOF_REGS + 4); |
| 555 | set_gdbarch_register_byte (gdbarch, i386_linux_register_byte); |
| 556 | set_gdbarch_register_raw_size (gdbarch, i386_linux_register_raw_size); |
| 557 | |
| 558 | tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */ |
| 559 | |
| 560 | /* When the i386 Linux kernel calls a signal handler, the return |
| 561 | address points to a bit of code on the stack. These definitions |
| 562 | are used to identify this bit of code as a signal trampoline in |
| 563 | order to support backtracing through calls to signal handlers. */ |
| 564 | |
| 565 | set_gdbarch_pc_in_sigtramp (gdbarch, i386_linux_pc_in_sigtramp); |
| 566 | set_gdbarch_frame_chain (gdbarch, i386_linux_frame_chain); |
| 567 | set_gdbarch_frame_saved_pc (gdbarch, i386_linux_frame_saved_pc); |
| 568 | set_gdbarch_saved_pc_after_call (gdbarch, i386_linux_saved_pc_after_call); |
| 569 | |
| 570 | set_solib_svr4_fetch_link_map_offsets (gdbarch, |
| 571 | i386_linux_svr4_fetch_link_map_offsets); |
| 572 | } |
| 573 | |
| 574 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 575 | extern void _initialize_i386_linux_tdep (void); |
| 576 | |
| 577 | void |
| 578 | _initialize_i386_linux_tdep (void) |
| 579 | { |
| 580 | gdbarch_register_osabi (bfd_arch_i386, GDB_OSABI_LINUX, |
| 581 | i386_linux_init_abi); |
| 582 | } |