| 1 | /* Target-dependent code for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 1986, 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, |
| 4 | 1997, 2000, 2001, 2002, 2003 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "frame.h" |
| 25 | #include "inferior.h" |
| 26 | #include "symtab.h" |
| 27 | #include "target.h" |
| 28 | #include "gdbcore.h" |
| 29 | #include "gdbcmd.h" |
| 30 | #include "symfile.h" |
| 31 | #include "objfiles.h" |
| 32 | #include "regcache.h" |
| 33 | #include "value.h" |
| 34 | #include "osabi.h" |
| 35 | |
| 36 | #include "solib-svr4.h" |
| 37 | #include "ppc-tdep.h" |
| 38 | |
| 39 | /* The following instructions are used in the signal trampoline code |
| 40 | on GNU/Linux PPC. The kernel used to use magic syscalls 0x6666 and |
| 41 | 0x7777 but now uses the sigreturn syscalls. We check for both. */ |
| 42 | #define INSTR_LI_R0_0x6666 0x38006666 |
| 43 | #define INSTR_LI_R0_0x7777 0x38007777 |
| 44 | #define INSTR_LI_R0_NR_sigreturn 0x38000077 |
| 45 | #define INSTR_LI_R0_NR_rt_sigreturn 0x380000AC |
| 46 | |
| 47 | #define INSTR_SC 0x44000002 |
| 48 | |
| 49 | /* Since the *-tdep.c files are platform independent (i.e, they may be |
| 50 | used to build cross platform debuggers), we can't include system |
| 51 | headers. Therefore, details concerning the sigcontext structure |
| 52 | must be painstakingly rerecorded. What's worse, if these details |
| 53 | ever change in the header files, they'll have to be changed here |
| 54 | as well. */ |
| 55 | |
| 56 | /* __SIGNAL_FRAMESIZE from <asm/ptrace.h> */ |
| 57 | #define PPC_LINUX_SIGNAL_FRAMESIZE 64 |
| 58 | |
| 59 | /* From <asm/sigcontext.h>, offsetof(struct sigcontext_struct, regs) == 0x1c */ |
| 60 | #define PPC_LINUX_REGS_PTR_OFFSET (PPC_LINUX_SIGNAL_FRAMESIZE + 0x1c) |
| 61 | |
| 62 | /* From <asm/sigcontext.h>, |
| 63 | offsetof(struct sigcontext_struct, handler) == 0x14 */ |
| 64 | #define PPC_LINUX_HANDLER_PTR_OFFSET (PPC_LINUX_SIGNAL_FRAMESIZE + 0x14) |
| 65 | |
| 66 | /* From <asm/ptrace.h>, values for PT_NIP, PT_R1, and PT_LNK */ |
| 67 | #define PPC_LINUX_PT_R0 0 |
| 68 | #define PPC_LINUX_PT_R1 1 |
| 69 | #define PPC_LINUX_PT_R2 2 |
| 70 | #define PPC_LINUX_PT_R3 3 |
| 71 | #define PPC_LINUX_PT_R4 4 |
| 72 | #define PPC_LINUX_PT_R5 5 |
| 73 | #define PPC_LINUX_PT_R6 6 |
| 74 | #define PPC_LINUX_PT_R7 7 |
| 75 | #define PPC_LINUX_PT_R8 8 |
| 76 | #define PPC_LINUX_PT_R9 9 |
| 77 | #define PPC_LINUX_PT_R10 10 |
| 78 | #define PPC_LINUX_PT_R11 11 |
| 79 | #define PPC_LINUX_PT_R12 12 |
| 80 | #define PPC_LINUX_PT_R13 13 |
| 81 | #define PPC_LINUX_PT_R14 14 |
| 82 | #define PPC_LINUX_PT_R15 15 |
| 83 | #define PPC_LINUX_PT_R16 16 |
| 84 | #define PPC_LINUX_PT_R17 17 |
| 85 | #define PPC_LINUX_PT_R18 18 |
| 86 | #define PPC_LINUX_PT_R19 19 |
| 87 | #define PPC_LINUX_PT_R20 20 |
| 88 | #define PPC_LINUX_PT_R21 21 |
| 89 | #define PPC_LINUX_PT_R22 22 |
| 90 | #define PPC_LINUX_PT_R23 23 |
| 91 | #define PPC_LINUX_PT_R24 24 |
| 92 | #define PPC_LINUX_PT_R25 25 |
| 93 | #define PPC_LINUX_PT_R26 26 |
| 94 | #define PPC_LINUX_PT_R27 27 |
| 95 | #define PPC_LINUX_PT_R28 28 |
| 96 | #define PPC_LINUX_PT_R29 29 |
| 97 | #define PPC_LINUX_PT_R30 30 |
| 98 | #define PPC_LINUX_PT_R31 31 |
| 99 | #define PPC_LINUX_PT_NIP 32 |
| 100 | #define PPC_LINUX_PT_MSR 33 |
| 101 | #define PPC_LINUX_PT_CTR 35 |
| 102 | #define PPC_LINUX_PT_LNK 36 |
| 103 | #define PPC_LINUX_PT_XER 37 |
| 104 | #define PPC_LINUX_PT_CCR 38 |
| 105 | #define PPC_LINUX_PT_MQ 39 |
| 106 | #define PPC_LINUX_PT_FPR0 48 /* each FP reg occupies 2 slots in this space */ |
| 107 | #define PPC_LINUX_PT_FPR31 (PPC_LINUX_PT_FPR0 + 2*31) |
| 108 | #define PPC_LINUX_PT_FPSCR (PPC_LINUX_PT_FPR0 + 2*32 + 1) |
| 109 | |
| 110 | static int ppc_linux_at_sigtramp_return_path (CORE_ADDR pc); |
| 111 | |
| 112 | /* Determine if pc is in a signal trampoline... |
| 113 | |
| 114 | Ha! That's not what this does at all. wait_for_inferior in |
| 115 | infrun.c calls PC_IN_SIGTRAMP in order to detect entry into a |
| 116 | signal trampoline just after delivery of a signal. But on |
| 117 | GNU/Linux, signal trampolines are used for the return path only. |
| 118 | The kernel sets things up so that the signal handler is called |
| 119 | directly. |
| 120 | |
| 121 | If we use in_sigtramp2() in place of in_sigtramp() (see below) |
| 122 | we'll (often) end up with stop_pc in the trampoline and prev_pc in |
| 123 | the (now exited) handler. The code there will cause a temporary |
| 124 | breakpoint to be set on prev_pc which is not very likely to get hit |
| 125 | again. |
| 126 | |
| 127 | If this is confusing, think of it this way... the code in |
| 128 | wait_for_inferior() needs to be able to detect entry into a signal |
| 129 | trampoline just after a signal is delivered, not after the handler |
| 130 | has been run. |
| 131 | |
| 132 | So, we define in_sigtramp() below to return 1 if the following is |
| 133 | true: |
| 134 | |
| 135 | 1) The previous frame is a real signal trampoline. |
| 136 | |
| 137 | - and - |
| 138 | |
| 139 | 2) pc is at the first or second instruction of the corresponding |
| 140 | handler. |
| 141 | |
| 142 | Why the second instruction? It seems that wait_for_inferior() |
| 143 | never sees the first instruction when single stepping. When a |
| 144 | signal is delivered while stepping, the next instruction that |
| 145 | would've been stepped over isn't, instead a signal is delivered and |
| 146 | the first instruction of the handler is stepped over instead. That |
| 147 | puts us on the second instruction. (I added the test for the |
| 148 | first instruction long after the fact, just in case the observed |
| 149 | behavior is ever fixed.) |
| 150 | |
| 151 | PC_IN_SIGTRAMP is called from blockframe.c as well in order to set |
| 152 | the frame's type (if a SIGTRAMP_FRAME). Because of our strange |
| 153 | definition of in_sigtramp below, we can't rely on the frame's type |
| 154 | getting set correctly from within blockframe.c. This is why we |
| 155 | take pains to set it in init_extra_frame_info(). |
| 156 | |
| 157 | NOTE: cagney/2002-11-10: I suspect the real problem here is that |
| 158 | the get_prev_frame() only initializes the frame's type after the |
| 159 | call to INIT_FRAME_INFO. get_prev_frame() should be fixed, this |
| 160 | code shouldn't be working its way around a bug :-(. */ |
| 161 | |
| 162 | int |
| 163 | ppc_linux_in_sigtramp (CORE_ADDR pc, char *func_name) |
| 164 | { |
| 165 | CORE_ADDR lr; |
| 166 | CORE_ADDR sp; |
| 167 | CORE_ADDR tramp_sp; |
| 168 | char buf[4]; |
| 169 | CORE_ADDR handler; |
| 170 | |
| 171 | lr = read_register (gdbarch_tdep (current_gdbarch)->ppc_lr_regnum); |
| 172 | if (!ppc_linux_at_sigtramp_return_path (lr)) |
| 173 | return 0; |
| 174 | |
| 175 | sp = read_register (SP_REGNUM); |
| 176 | |
| 177 | if (target_read_memory (sp, buf, sizeof (buf)) != 0) |
| 178 | return 0; |
| 179 | |
| 180 | tramp_sp = extract_unsigned_integer (buf, 4); |
| 181 | |
| 182 | if (target_read_memory (tramp_sp + PPC_LINUX_HANDLER_PTR_OFFSET, buf, |
| 183 | sizeof (buf)) != 0) |
| 184 | return 0; |
| 185 | |
| 186 | handler = extract_unsigned_integer (buf, 4); |
| 187 | |
| 188 | return (pc == handler || pc == handler + 4); |
| 189 | } |
| 190 | |
| 191 | static int |
| 192 | insn_is_sigreturn (unsigned long pcinsn) |
| 193 | { |
| 194 | switch(pcinsn) |
| 195 | { |
| 196 | case INSTR_LI_R0_0x6666: |
| 197 | case INSTR_LI_R0_0x7777: |
| 198 | case INSTR_LI_R0_NR_sigreturn: |
| 199 | case INSTR_LI_R0_NR_rt_sigreturn: |
| 200 | return 1; |
| 201 | default: |
| 202 | return 0; |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | /* |
| 207 | * The signal handler trampoline is on the stack and consists of exactly |
| 208 | * two instructions. The easiest and most accurate way of determining |
| 209 | * whether the pc is in one of these trampolines is by inspecting the |
| 210 | * instructions. It'd be faster though if we could find a way to do this |
| 211 | * via some simple address comparisons. |
| 212 | */ |
| 213 | static int |
| 214 | ppc_linux_at_sigtramp_return_path (CORE_ADDR pc) |
| 215 | { |
| 216 | char buf[12]; |
| 217 | unsigned long pcinsn; |
| 218 | if (target_read_memory (pc - 4, buf, sizeof (buf)) != 0) |
| 219 | return 0; |
| 220 | |
| 221 | /* extract the instruction at the pc */ |
| 222 | pcinsn = extract_unsigned_integer (buf + 4, 4); |
| 223 | |
| 224 | return ( |
| 225 | (insn_is_sigreturn (pcinsn) |
| 226 | && extract_unsigned_integer (buf + 8, 4) == INSTR_SC) |
| 227 | || |
| 228 | (pcinsn == INSTR_SC |
| 229 | && insn_is_sigreturn (extract_unsigned_integer (buf, 4)))); |
| 230 | } |
| 231 | |
| 232 | static CORE_ADDR |
| 233 | ppc_linux_skip_trampoline_code (CORE_ADDR pc) |
| 234 | { |
| 235 | char buf[4]; |
| 236 | struct obj_section *sect; |
| 237 | struct objfile *objfile; |
| 238 | unsigned long insn; |
| 239 | CORE_ADDR plt_start = 0; |
| 240 | CORE_ADDR symtab = 0; |
| 241 | CORE_ADDR strtab = 0; |
| 242 | int num_slots = -1; |
| 243 | int reloc_index = -1; |
| 244 | CORE_ADDR plt_table; |
| 245 | CORE_ADDR reloc; |
| 246 | CORE_ADDR sym; |
| 247 | long symidx; |
| 248 | char symname[1024]; |
| 249 | struct minimal_symbol *msymbol; |
| 250 | |
| 251 | /* Find the section pc is in; return if not in .plt */ |
| 252 | sect = find_pc_section (pc); |
| 253 | if (!sect || strcmp (sect->the_bfd_section->name, ".plt") != 0) |
| 254 | return 0; |
| 255 | |
| 256 | objfile = sect->objfile; |
| 257 | |
| 258 | /* Pick up the instruction at pc. It had better be of the |
| 259 | form |
| 260 | li r11, IDX |
| 261 | |
| 262 | where IDX is an index into the plt_table. */ |
| 263 | |
| 264 | if (target_read_memory (pc, buf, 4) != 0) |
| 265 | return 0; |
| 266 | insn = extract_unsigned_integer (buf, 4); |
| 267 | |
| 268 | if ((insn & 0xffff0000) != 0x39600000 /* li r11, VAL */ ) |
| 269 | return 0; |
| 270 | |
| 271 | reloc_index = (insn << 16) >> 16; |
| 272 | |
| 273 | /* Find the objfile that pc is in and obtain the information |
| 274 | necessary for finding the symbol name. */ |
| 275 | for (sect = objfile->sections; sect < objfile->sections_end; ++sect) |
| 276 | { |
| 277 | const char *secname = sect->the_bfd_section->name; |
| 278 | if (strcmp (secname, ".plt") == 0) |
| 279 | plt_start = sect->addr; |
| 280 | else if (strcmp (secname, ".rela.plt") == 0) |
| 281 | num_slots = ((int) sect->endaddr - (int) sect->addr) / 12; |
| 282 | else if (strcmp (secname, ".dynsym") == 0) |
| 283 | symtab = sect->addr; |
| 284 | else if (strcmp (secname, ".dynstr") == 0) |
| 285 | strtab = sect->addr; |
| 286 | } |
| 287 | |
| 288 | /* Make sure we have all the information we need. */ |
| 289 | if (plt_start == 0 || num_slots == -1 || symtab == 0 || strtab == 0) |
| 290 | return 0; |
| 291 | |
| 292 | /* Compute the value of the plt table */ |
| 293 | plt_table = plt_start + 72 + 8 * num_slots; |
| 294 | |
| 295 | /* Get address of the relocation entry (Elf32_Rela) */ |
| 296 | if (target_read_memory (plt_table + reloc_index, buf, 4) != 0) |
| 297 | return 0; |
| 298 | reloc = extract_unsigned_integer (buf, 4); |
| 299 | |
| 300 | sect = find_pc_section (reloc); |
| 301 | if (!sect) |
| 302 | return 0; |
| 303 | |
| 304 | if (strcmp (sect->the_bfd_section->name, ".text") == 0) |
| 305 | return reloc; |
| 306 | |
| 307 | /* Now get the r_info field which is the relocation type and symbol |
| 308 | index. */ |
| 309 | if (target_read_memory (reloc + 4, buf, 4) != 0) |
| 310 | return 0; |
| 311 | symidx = extract_unsigned_integer (buf, 4); |
| 312 | |
| 313 | /* Shift out the relocation type leaving just the symbol index */ |
| 314 | /* symidx = ELF32_R_SYM(symidx); */ |
| 315 | symidx = symidx >> 8; |
| 316 | |
| 317 | /* compute the address of the symbol */ |
| 318 | sym = symtab + symidx * 4; |
| 319 | |
| 320 | /* Fetch the string table index */ |
| 321 | if (target_read_memory (sym, buf, 4) != 0) |
| 322 | return 0; |
| 323 | symidx = extract_unsigned_integer (buf, 4); |
| 324 | |
| 325 | /* Fetch the string; we don't know how long it is. Is it possible |
| 326 | that the following will fail because we're trying to fetch too |
| 327 | much? */ |
| 328 | if (target_read_memory (strtab + symidx, symname, sizeof (symname)) != 0) |
| 329 | return 0; |
| 330 | |
| 331 | /* This might not work right if we have multiple symbols with the |
| 332 | same name; the only way to really get it right is to perform |
| 333 | the same sort of lookup as the dynamic linker. */ |
| 334 | msymbol = lookup_minimal_symbol_text (symname, NULL); |
| 335 | if (!msymbol) |
| 336 | return 0; |
| 337 | |
| 338 | return SYMBOL_VALUE_ADDRESS (msymbol); |
| 339 | } |
| 340 | |
| 341 | /* The rs6000 version of FRAME_SAVED_PC will almost work for us. The |
| 342 | signal handler details are different, so we'll handle those here |
| 343 | and call the rs6000 version to do the rest. */ |
| 344 | CORE_ADDR |
| 345 | ppc_linux_frame_saved_pc (struct frame_info *fi) |
| 346 | { |
| 347 | if ((get_frame_type (fi) == SIGTRAMP_FRAME)) |
| 348 | { |
| 349 | CORE_ADDR regs_addr = |
| 350 | read_memory_integer (get_frame_base (fi) |
| 351 | + PPC_LINUX_REGS_PTR_OFFSET, 4); |
| 352 | /* return the NIP in the regs array */ |
| 353 | return read_memory_integer (regs_addr + 4 * PPC_LINUX_PT_NIP, 4); |
| 354 | } |
| 355 | else if (get_next_frame (fi) |
| 356 | && (get_frame_type (get_next_frame (fi)) == SIGTRAMP_FRAME)) |
| 357 | { |
| 358 | CORE_ADDR regs_addr = |
| 359 | read_memory_integer (get_frame_base (get_next_frame (fi)) |
| 360 | + PPC_LINUX_REGS_PTR_OFFSET, 4); |
| 361 | /* return LNK in the regs array */ |
| 362 | return read_memory_integer (regs_addr + 4 * PPC_LINUX_PT_LNK, 4); |
| 363 | } |
| 364 | else |
| 365 | return rs6000_frame_saved_pc (fi); |
| 366 | } |
| 367 | |
| 368 | void |
| 369 | ppc_linux_init_extra_frame_info (int fromleaf, struct frame_info *fi) |
| 370 | { |
| 371 | rs6000_init_extra_frame_info (fromleaf, fi); |
| 372 | |
| 373 | if (get_next_frame (fi) != 0) |
| 374 | { |
| 375 | /* We're called from get_prev_frame_info; check to see if |
| 376 | this is a signal frame by looking to see if the pc points |
| 377 | at trampoline code */ |
| 378 | if (ppc_linux_at_sigtramp_return_path (get_frame_pc (fi))) |
| 379 | deprecated_set_frame_type (fi, SIGTRAMP_FRAME); |
| 380 | else |
| 381 | /* FIXME: cagney/2002-11-10: Is this double bogus? What |
| 382 | happens if the frame has previously been marked as a dummy? */ |
| 383 | deprecated_set_frame_type (fi, NORMAL_FRAME); |
| 384 | } |
| 385 | } |
| 386 | |
| 387 | int |
| 388 | ppc_linux_frameless_function_invocation (struct frame_info *fi) |
| 389 | { |
| 390 | /* We'll find the wrong thing if we let |
| 391 | rs6000_frameless_function_invocation () search for a signal trampoline */ |
| 392 | if (ppc_linux_at_sigtramp_return_path (get_frame_pc (fi))) |
| 393 | return 0; |
| 394 | else |
| 395 | return rs6000_frameless_function_invocation (fi); |
| 396 | } |
| 397 | |
| 398 | void |
| 399 | ppc_linux_frame_init_saved_regs (struct frame_info *fi) |
| 400 | { |
| 401 | if ((get_frame_type (fi) == SIGTRAMP_FRAME)) |
| 402 | { |
| 403 | CORE_ADDR regs_addr; |
| 404 | int i; |
| 405 | if (deprecated_get_frame_saved_regs (fi)) |
| 406 | return; |
| 407 | |
| 408 | frame_saved_regs_zalloc (fi); |
| 409 | |
| 410 | regs_addr = |
| 411 | read_memory_integer (get_frame_base (fi) |
| 412 | + PPC_LINUX_REGS_PTR_OFFSET, 4); |
| 413 | deprecated_get_frame_saved_regs (fi)[PC_REGNUM] = regs_addr + 4 * PPC_LINUX_PT_NIP; |
| 414 | deprecated_get_frame_saved_regs (fi)[gdbarch_tdep (current_gdbarch)->ppc_ps_regnum] = |
| 415 | regs_addr + 4 * PPC_LINUX_PT_MSR; |
| 416 | deprecated_get_frame_saved_regs (fi)[gdbarch_tdep (current_gdbarch)->ppc_cr_regnum] = |
| 417 | regs_addr + 4 * PPC_LINUX_PT_CCR; |
| 418 | deprecated_get_frame_saved_regs (fi)[gdbarch_tdep (current_gdbarch)->ppc_lr_regnum] = |
| 419 | regs_addr + 4 * PPC_LINUX_PT_LNK; |
| 420 | deprecated_get_frame_saved_regs (fi)[gdbarch_tdep (current_gdbarch)->ppc_ctr_regnum] = |
| 421 | regs_addr + 4 * PPC_LINUX_PT_CTR; |
| 422 | deprecated_get_frame_saved_regs (fi)[gdbarch_tdep (current_gdbarch)->ppc_xer_regnum] = |
| 423 | regs_addr + 4 * PPC_LINUX_PT_XER; |
| 424 | deprecated_get_frame_saved_regs (fi)[gdbarch_tdep (current_gdbarch)->ppc_mq_regnum] = |
| 425 | regs_addr + 4 * PPC_LINUX_PT_MQ; |
| 426 | for (i = 0; i < 32; i++) |
| 427 | deprecated_get_frame_saved_regs (fi)[gdbarch_tdep (current_gdbarch)->ppc_gp0_regnum + i] = |
| 428 | regs_addr + 4 * PPC_LINUX_PT_R0 + 4 * i; |
| 429 | for (i = 0; i < 32; i++) |
| 430 | deprecated_get_frame_saved_regs (fi)[FP0_REGNUM + i] = regs_addr + 4 * PPC_LINUX_PT_FPR0 + 8 * i; |
| 431 | } |
| 432 | else |
| 433 | rs6000_frame_init_saved_regs (fi); |
| 434 | } |
| 435 | |
| 436 | CORE_ADDR |
| 437 | ppc_linux_frame_chain (struct frame_info *thisframe) |
| 438 | { |
| 439 | /* Kernel properly constructs the frame chain for the handler */ |
| 440 | if ((get_frame_type (thisframe) == SIGTRAMP_FRAME)) |
| 441 | return read_memory_integer (get_frame_base (thisframe), 4); |
| 442 | else |
| 443 | return rs6000_frame_chain (thisframe); |
| 444 | } |
| 445 | |
| 446 | /* ppc_linux_memory_remove_breakpoints attempts to remove a breakpoint |
| 447 | in much the same fashion as memory_remove_breakpoint in mem-break.c, |
| 448 | but is careful not to write back the previous contents if the code |
| 449 | in question has changed in between inserting the breakpoint and |
| 450 | removing it. |
| 451 | |
| 452 | Here is the problem that we're trying to solve... |
| 453 | |
| 454 | Once upon a time, before introducing this function to remove |
| 455 | breakpoints from the inferior, setting a breakpoint on a shared |
| 456 | library function prior to running the program would not work |
| 457 | properly. In order to understand the problem, it is first |
| 458 | necessary to understand a little bit about dynamic linking on |
| 459 | this platform. |
| 460 | |
| 461 | A call to a shared library function is accomplished via a bl |
| 462 | (branch-and-link) instruction whose branch target is an entry |
| 463 | in the procedure linkage table (PLT). The PLT in the object |
| 464 | file is uninitialized. To gdb, prior to running the program, the |
| 465 | entries in the PLT are all zeros. |
| 466 | |
| 467 | Once the program starts running, the shared libraries are loaded |
| 468 | and the procedure linkage table is initialized, but the entries in |
| 469 | the table are not (necessarily) resolved. Once a function is |
| 470 | actually called, the code in the PLT is hit and the function is |
| 471 | resolved. In order to better illustrate this, an example is in |
| 472 | order; the following example is from the gdb testsuite. |
| 473 | |
| 474 | We start the program shmain. |
| 475 | |
| 476 | [kev@arroyo testsuite]$ ../gdb gdb.base/shmain |
| 477 | [...] |
| 478 | |
| 479 | We place two breakpoints, one on shr1 and the other on main. |
| 480 | |
| 481 | (gdb) b shr1 |
| 482 | Breakpoint 1 at 0x100409d4 |
| 483 | (gdb) b main |
| 484 | Breakpoint 2 at 0x100006a0: file gdb.base/shmain.c, line 44. |
| 485 | |
| 486 | Examine the instruction (and the immediatly following instruction) |
| 487 | upon which the breakpoint was placed. Note that the PLT entry |
| 488 | for shr1 contains zeros. |
| 489 | |
| 490 | (gdb) x/2i 0x100409d4 |
| 491 | 0x100409d4 <shr1>: .long 0x0 |
| 492 | 0x100409d8 <shr1+4>: .long 0x0 |
| 493 | |
| 494 | Now run 'til main. |
| 495 | |
| 496 | (gdb) r |
| 497 | Starting program: gdb.base/shmain |
| 498 | Breakpoint 1 at 0xffaf790: file gdb.base/shr1.c, line 19. |
| 499 | |
| 500 | Breakpoint 2, main () |
| 501 | at gdb.base/shmain.c:44 |
| 502 | 44 g = 1; |
| 503 | |
| 504 | Examine the PLT again. Note that the loading of the shared |
| 505 | library has initialized the PLT to code which loads a constant |
| 506 | (which I think is an index into the GOT) into r11 and then |
| 507 | branchs a short distance to the code which actually does the |
| 508 | resolving. |
| 509 | |
| 510 | (gdb) x/2i 0x100409d4 |
| 511 | 0x100409d4 <shr1>: li r11,4 |
| 512 | 0x100409d8 <shr1+4>: b 0x10040984 <sg+4> |
| 513 | (gdb) c |
| 514 | Continuing. |
| 515 | |
| 516 | Breakpoint 1, shr1 (x=1) |
| 517 | at gdb.base/shr1.c:19 |
| 518 | 19 l = 1; |
| 519 | |
| 520 | Now we've hit the breakpoint at shr1. (The breakpoint was |
| 521 | reset from the PLT entry to the actual shr1 function after the |
| 522 | shared library was loaded.) Note that the PLT entry has been |
| 523 | resolved to contain a branch that takes us directly to shr1. |
| 524 | (The real one, not the PLT entry.) |
| 525 | |
| 526 | (gdb) x/2i 0x100409d4 |
| 527 | 0x100409d4 <shr1>: b 0xffaf76c <shr1> |
| 528 | 0x100409d8 <shr1+4>: b 0x10040984 <sg+4> |
| 529 | |
| 530 | The thing to note here is that the PLT entry for shr1 has been |
| 531 | changed twice. |
| 532 | |
| 533 | Now the problem should be obvious. GDB places a breakpoint (a |
| 534 | trap instruction) on the zero value of the PLT entry for shr1. |
| 535 | Later on, after the shared library had been loaded and the PLT |
| 536 | initialized, GDB gets a signal indicating this fact and attempts |
| 537 | (as it always does when it stops) to remove all the breakpoints. |
| 538 | |
| 539 | The breakpoint removal was causing the former contents (a zero |
| 540 | word) to be written back to the now initialized PLT entry thus |
| 541 | destroying a portion of the initialization that had occurred only a |
| 542 | short time ago. When execution continued, the zero word would be |
| 543 | executed as an instruction an an illegal instruction trap was |
| 544 | generated instead. (0 is not a legal instruction.) |
| 545 | |
| 546 | The fix for this problem was fairly straightforward. The function |
| 547 | memory_remove_breakpoint from mem-break.c was copied to this file, |
| 548 | modified slightly, and renamed to ppc_linux_memory_remove_breakpoint. |
| 549 | In tm-linux.h, MEMORY_REMOVE_BREAKPOINT is defined to call this new |
| 550 | function. |
| 551 | |
| 552 | The differences between ppc_linux_memory_remove_breakpoint () and |
| 553 | memory_remove_breakpoint () are minor. All that the former does |
| 554 | that the latter does not is check to make sure that the breakpoint |
| 555 | location actually contains a breakpoint (trap instruction) prior |
| 556 | to attempting to write back the old contents. If it does contain |
| 557 | a trap instruction, we allow the old contents to be written back. |
| 558 | Otherwise, we silently do nothing. |
| 559 | |
| 560 | The big question is whether memory_remove_breakpoint () should be |
| 561 | changed to have the same functionality. The downside is that more |
| 562 | traffic is generated for remote targets since we'll have an extra |
| 563 | fetch of a memory word each time a breakpoint is removed. |
| 564 | |
| 565 | For the time being, we'll leave this self-modifying-code-friendly |
| 566 | version in ppc-linux-tdep.c, but it ought to be migrated somewhere |
| 567 | else in the event that some other platform has similar needs with |
| 568 | regard to removing breakpoints in some potentially self modifying |
| 569 | code. */ |
| 570 | int |
| 571 | ppc_linux_memory_remove_breakpoint (CORE_ADDR addr, char *contents_cache) |
| 572 | { |
| 573 | const unsigned char *bp; |
| 574 | int val; |
| 575 | int bplen; |
| 576 | char old_contents[BREAKPOINT_MAX]; |
| 577 | |
| 578 | /* Determine appropriate breakpoint contents and size for this address. */ |
| 579 | bp = BREAKPOINT_FROM_PC (&addr, &bplen); |
| 580 | if (bp == NULL) |
| 581 | error ("Software breakpoints not implemented for this target."); |
| 582 | |
| 583 | val = target_read_memory (addr, old_contents, bplen); |
| 584 | |
| 585 | /* If our breakpoint is no longer at the address, this means that the |
| 586 | program modified the code on us, so it is wrong to put back the |
| 587 | old value */ |
| 588 | if (val == 0 && memcmp (bp, old_contents, bplen) == 0) |
| 589 | val = target_write_memory (addr, contents_cache, bplen); |
| 590 | |
| 591 | return val; |
| 592 | } |
| 593 | |
| 594 | /* For historic reasons, PPC 32 GNU/Linux follows PowerOpen rather |
| 595 | than the 32 bit SYSV R4 ABI structure return convention - all |
| 596 | structures, no matter their size, are put in memory. Vectors, |
| 597 | which were added later, do get returned in a register though. */ |
| 598 | |
| 599 | static int |
| 600 | ppc_linux_use_struct_convention (int gcc_p, struct type *value_type) |
| 601 | { |
| 602 | if ((TYPE_LENGTH (value_type) == 16 || TYPE_LENGTH (value_type) == 8) |
| 603 | && TYPE_VECTOR (value_type)) |
| 604 | return 0; |
| 605 | return 1; |
| 606 | } |
| 607 | |
| 608 | /* Fetch (and possibly build) an appropriate link_map_offsets |
| 609 | structure for GNU/Linux PPC targets using the struct offsets |
| 610 | defined in link.h (but without actual reference to that file). |
| 611 | |
| 612 | This makes it possible to access GNU/Linux PPC shared libraries |
| 613 | from a GDB that was not built on an GNU/Linux PPC host (for cross |
| 614 | debugging). */ |
| 615 | |
| 616 | struct link_map_offsets * |
| 617 | ppc_linux_svr4_fetch_link_map_offsets (void) |
| 618 | { |
| 619 | static struct link_map_offsets lmo; |
| 620 | static struct link_map_offsets *lmp = NULL; |
| 621 | |
| 622 | if (lmp == NULL) |
| 623 | { |
| 624 | lmp = &lmo; |
| 625 | |
| 626 | lmo.r_debug_size = 8; /* The actual size is 20 bytes, but |
| 627 | this is all we need. */ |
| 628 | lmo.r_map_offset = 4; |
| 629 | lmo.r_map_size = 4; |
| 630 | |
| 631 | lmo.link_map_size = 20; /* The actual size is 560 bytes, but |
| 632 | this is all we need. */ |
| 633 | lmo.l_addr_offset = 0; |
| 634 | lmo.l_addr_size = 4; |
| 635 | |
| 636 | lmo.l_name_offset = 4; |
| 637 | lmo.l_name_size = 4; |
| 638 | |
| 639 | lmo.l_next_offset = 12; |
| 640 | lmo.l_next_size = 4; |
| 641 | |
| 642 | lmo.l_prev_offset = 16; |
| 643 | lmo.l_prev_size = 4; |
| 644 | } |
| 645 | |
| 646 | return lmp; |
| 647 | } |
| 648 | |
| 649 | |
| 650 | /* Macros for matching instructions. Note that, since all the |
| 651 | operands are masked off before they're or-ed into the instruction, |
| 652 | you can use -1 to make masks. */ |
| 653 | |
| 654 | #define insn_d(opcd, rts, ra, d) \ |
| 655 | ((((opcd) & 0x3f) << 26) \ |
| 656 | | (((rts) & 0x1f) << 21) \ |
| 657 | | (((ra) & 0x1f) << 16) \ |
| 658 | | ((d) & 0xffff)) |
| 659 | |
| 660 | #define insn_ds(opcd, rts, ra, d, xo) \ |
| 661 | ((((opcd) & 0x3f) << 26) \ |
| 662 | | (((rts) & 0x1f) << 21) \ |
| 663 | | (((ra) & 0x1f) << 16) \ |
| 664 | | ((d) & 0xfffc) \ |
| 665 | | ((xo) & 0x3)) |
| 666 | |
| 667 | #define insn_xfx(opcd, rts, spr, xo) \ |
| 668 | ((((opcd) & 0x3f) << 26) \ |
| 669 | | (((rts) & 0x1f) << 21) \ |
| 670 | | (((spr) & 0x1f) << 16) \ |
| 671 | | (((spr) & 0x3e0) << 6) \ |
| 672 | | (((xo) & 0x3ff) << 1)) |
| 673 | |
| 674 | /* Read a PPC instruction from memory. PPC instructions are always |
| 675 | big-endian, no matter what endianness the program is running in, so |
| 676 | we can't use read_memory_integer or one of its friends here. */ |
| 677 | static unsigned int |
| 678 | read_insn (CORE_ADDR pc) |
| 679 | { |
| 680 | unsigned char buf[4]; |
| 681 | |
| 682 | read_memory (pc, buf, 4); |
| 683 | return (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]; |
| 684 | } |
| 685 | |
| 686 | |
| 687 | /* An instruction to match. */ |
| 688 | struct insn_pattern |
| 689 | { |
| 690 | unsigned int mask; /* mask the insn with this... */ |
| 691 | unsigned int data; /* ...and see if it matches this. */ |
| 692 | int optional; /* If non-zero, this insn may be absent. */ |
| 693 | }; |
| 694 | |
| 695 | /* Return non-zero if the instructions at PC match the series |
| 696 | described in PATTERN, or zero otherwise. PATTERN is an array of |
| 697 | 'struct insn_pattern' objects, terminated by an entry whose mask is |
| 698 | zero. |
| 699 | |
| 700 | When the match is successful, fill INSN[i] with what PATTERN[i] |
| 701 | matched. If PATTERN[i] is optional, and the instruction wasn't |
| 702 | present, set INSN[i] to 0 (which is not a valid PPC instruction). |
| 703 | INSN should have as many elements as PATTERN. Note that, if |
| 704 | PATTERN contains optional instructions which aren't present in |
| 705 | memory, then INSN will have holes, so INSN[i] isn't necessarily the |
| 706 | i'th instruction in memory. */ |
| 707 | static int |
| 708 | insns_match_pattern (CORE_ADDR pc, |
| 709 | struct insn_pattern *pattern, |
| 710 | unsigned int *insn) |
| 711 | { |
| 712 | int i; |
| 713 | |
| 714 | for (i = 0; pattern[i].mask; i++) |
| 715 | { |
| 716 | insn[i] = read_insn (pc); |
| 717 | if ((insn[i] & pattern[i].mask) == pattern[i].data) |
| 718 | pc += 4; |
| 719 | else if (pattern[i].optional) |
| 720 | insn[i] = 0; |
| 721 | else |
| 722 | return 0; |
| 723 | } |
| 724 | |
| 725 | return 1; |
| 726 | } |
| 727 | |
| 728 | |
| 729 | /* Return the 'd' field of the d-form instruction INSN, properly |
| 730 | sign-extended. */ |
| 731 | static CORE_ADDR |
| 732 | insn_d_field (unsigned int insn) |
| 733 | { |
| 734 | return ((((CORE_ADDR) insn & 0xffff) ^ 0x8000) - 0x8000); |
| 735 | } |
| 736 | |
| 737 | |
| 738 | /* Return the 'ds' field of the ds-form instruction INSN, with the two |
| 739 | zero bits concatenated at the right, and properly |
| 740 | sign-extended. */ |
| 741 | static CORE_ADDR |
| 742 | insn_ds_field (unsigned int insn) |
| 743 | { |
| 744 | return ((((CORE_ADDR) insn & 0xfffc) ^ 0x8000) - 0x8000); |
| 745 | } |
| 746 | |
| 747 | |
| 748 | /* If DESC is the address of a 64-bit PowerPC GNU/Linux function |
| 749 | descriptor, return the descriptor's entry point. */ |
| 750 | static CORE_ADDR |
| 751 | ppc64_desc_entry_point (CORE_ADDR desc) |
| 752 | { |
| 753 | /* The first word of the descriptor is the entry point. */ |
| 754 | return (CORE_ADDR) read_memory_unsigned_integer (desc, 8); |
| 755 | } |
| 756 | |
| 757 | |
| 758 | /* Pattern for the standard linkage function. These are built by |
| 759 | build_plt_stub in elf64-ppc.c, whose GLINK argument is always |
| 760 | zero. */ |
| 761 | static struct insn_pattern ppc64_standard_linkage[] = |
| 762 | { |
| 763 | /* addis r12, r2, <any> */ |
| 764 | { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 }, |
| 765 | |
| 766 | /* std r2, 40(r1) */ |
| 767 | { -1, insn_ds (62, 2, 1, 40, 0), 0 }, |
| 768 | |
| 769 | /* ld r11, <any>(r12) */ |
| 770 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, |
| 771 | |
| 772 | /* addis r12, r12, 1 <optional> */ |
| 773 | { insn_d (-1, -1, -1, -1), insn_d (15, 12, 2, 1), 1 }, |
| 774 | |
| 775 | /* ld r2, <any>(r12) */ |
| 776 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 }, |
| 777 | |
| 778 | /* addis r12, r12, 1 <optional> */ |
| 779 | { insn_d (-1, -1, -1, -1), insn_d (15, 12, 2, 1), 1 }, |
| 780 | |
| 781 | /* mtctr r11 */ |
| 782 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), |
| 783 | 0 }, |
| 784 | |
| 785 | /* ld r11, <any>(r12) */ |
| 786 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, |
| 787 | |
| 788 | /* bctr */ |
| 789 | { -1, 0x4e800420, 0 }, |
| 790 | |
| 791 | { 0, 0, 0 } |
| 792 | }; |
| 793 | #define PPC64_STANDARD_LINKAGE_LEN \ |
| 794 | (sizeof (ppc64_standard_linkage) / sizeof (ppc64_standard_linkage[0])) |
| 795 | |
| 796 | |
| 797 | /* Recognize a 64-bit PowerPC GNU/Linux linkage function --- what GDB |
| 798 | calls a "solib trampoline". */ |
| 799 | static int |
| 800 | ppc64_in_solib_call_trampoline (CORE_ADDR pc, char *name) |
| 801 | { |
| 802 | /* Detecting solib call trampolines on PPC64 GNU/Linux is a pain. |
| 803 | |
| 804 | It's not specifically solib call trampolines that are the issue. |
| 805 | Any call from one function to another function that uses a |
| 806 | different TOC requires a trampoline, to save the caller's TOC |
| 807 | pointer and then load the callee's TOC. An executable or shared |
| 808 | library may have more than one TOC, so even intra-object calls |
| 809 | may require a trampoline. Since executable and shared libraries |
| 810 | will all have their own distinct TOCs, every inter-object call is |
| 811 | also an inter-TOC call, and requires a trampoline --- so "solib |
| 812 | call trampolines" are just a special case. |
| 813 | |
| 814 | The 64-bit PowerPC GNU/Linux ABI calls these call trampolines |
| 815 | "linkage functions". Since they need to be near the functions |
| 816 | that call them, they all appear in .text, not in any special |
| 817 | section. The .plt section just contains an array of function |
| 818 | descriptors, from which the linkage functions load the callee's |
| 819 | entry point, TOC value, and environment pointer. So |
| 820 | in_plt_section is useless. The linkage functions don't have any |
| 821 | special linker symbols to name them, either. |
| 822 | |
| 823 | The only way I can see to recognize them is to actually look at |
| 824 | their code. They're generated by ppc_build_one_stub and some |
| 825 | other functions in bfd/elf64-ppc.c, so that should show us all |
| 826 | the instruction sequences we need to recognize. */ |
| 827 | unsigned int insn[PPC64_STANDARD_LINKAGE_LEN]; |
| 828 | |
| 829 | return insns_match_pattern (pc, ppc64_standard_linkage, insn); |
| 830 | } |
| 831 | |
| 832 | |
| 833 | /* When the dynamic linker is doing lazy symbol resolution, the first |
| 834 | call to a function in another object will go like this: |
| 835 | |
| 836 | - The user's function calls the linkage function: |
| 837 | |
| 838 | 100007c4: 4b ff fc d5 bl 10000498 |
| 839 | 100007c8: e8 41 00 28 ld r2,40(r1) |
| 840 | |
| 841 | - The linkage function loads the entry point (and other stuff) from |
| 842 | the function descriptor in the PLT, and jumps to it: |
| 843 | |
| 844 | 10000498: 3d 82 00 00 addis r12,r2,0 |
| 845 | 1000049c: f8 41 00 28 std r2,40(r1) |
| 846 | 100004a0: e9 6c 80 98 ld r11,-32616(r12) |
| 847 | 100004a4: e8 4c 80 a0 ld r2,-32608(r12) |
| 848 | 100004a8: 7d 69 03 a6 mtctr r11 |
| 849 | 100004ac: e9 6c 80 a8 ld r11,-32600(r12) |
| 850 | 100004b0: 4e 80 04 20 bctr |
| 851 | |
| 852 | - But since this is the first time that PLT entry has been used, it |
| 853 | sends control to its glink entry. That loads the number of the |
| 854 | PLT entry and jumps to the common glink0 code: |
| 855 | |
| 856 | 10000c98: 38 00 00 00 li r0,0 |
| 857 | 10000c9c: 4b ff ff dc b 10000c78 |
| 858 | |
| 859 | - The common glink0 code then transfers control to the dynamic |
| 860 | linker's fixup code: |
| 861 | |
| 862 | 10000c78: e8 41 00 28 ld r2,40(r1) |
| 863 | 10000c7c: 3d 82 00 00 addis r12,r2,0 |
| 864 | 10000c80: e9 6c 80 80 ld r11,-32640(r12) |
| 865 | 10000c84: e8 4c 80 88 ld r2,-32632(r12) |
| 866 | 10000c88: 7d 69 03 a6 mtctr r11 |
| 867 | 10000c8c: e9 6c 80 90 ld r11,-32624(r12) |
| 868 | 10000c90: 4e 80 04 20 bctr |
| 869 | |
| 870 | Eventually, this code will figure out how to skip all of this, |
| 871 | including the dynamic linker. At the moment, we just get through |
| 872 | the linkage function. */ |
| 873 | |
| 874 | /* If the current thread is about to execute a series of instructions |
| 875 | at PC matching the ppc64_standard_linkage pattern, and INSN is the result |
| 876 | from that pattern match, return the code address to which the |
| 877 | standard linkage function will send them. (This doesn't deal with |
| 878 | dynamic linker lazy symbol resolution stubs.) */ |
| 879 | static CORE_ADDR |
| 880 | ppc64_standard_linkage_target (CORE_ADDR pc, unsigned int *insn) |
| 881 | { |
| 882 | struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); |
| 883 | |
| 884 | /* The address of the function descriptor this linkage function |
| 885 | references. */ |
| 886 | CORE_ADDR desc |
| 887 | = ((CORE_ADDR) read_register (tdep->ppc_gp0_regnum + 2) |
| 888 | + (insn_d_field (insn[0]) << 16) |
| 889 | + insn_ds_field (insn[2])); |
| 890 | |
| 891 | /* The first word of the descriptor is the entry point. Return that. */ |
| 892 | return ppc64_desc_entry_point (desc); |
| 893 | } |
| 894 | |
| 895 | |
| 896 | /* Given that we've begun executing a call trampoline at PC, return |
| 897 | the entry point of the function the trampoline will go to. */ |
| 898 | static CORE_ADDR |
| 899 | ppc64_skip_trampoline_code (CORE_ADDR pc) |
| 900 | { |
| 901 | unsigned int ppc64_standard_linkage_insn[PPC64_STANDARD_LINKAGE_LEN]; |
| 902 | |
| 903 | if (insns_match_pattern (pc, ppc64_standard_linkage, |
| 904 | ppc64_standard_linkage_insn)) |
| 905 | return ppc64_standard_linkage_target (pc, ppc64_standard_linkage_insn); |
| 906 | else |
| 907 | return 0; |
| 908 | } |
| 909 | |
| 910 | |
| 911 | /* Support for CONVERT_FROM_FUNC_PTR_ADDR (ARCH, ADDR, TARG) on PPC64 |
| 912 | GNU/Linux. |
| 913 | |
| 914 | Usually a function pointer's representation is simply the address |
| 915 | of the function. On GNU/Linux on the 64-bit PowerPC however, a |
| 916 | function pointer is represented by a pointer to a TOC entry. This |
| 917 | TOC entry contains three words, the first word is the address of |
| 918 | the function, the second word is the TOC pointer (r2), and the |
| 919 | third word is the static chain value. Throughout GDB it is |
| 920 | currently assumed that a function pointer contains the address of |
| 921 | the function, which is not easy to fix. In addition, the |
| 922 | conversion of a function address to a function pointer would |
| 923 | require allocation of a TOC entry in the inferior's memory space, |
| 924 | with all its drawbacks. To be able to call C++ virtual methods in |
| 925 | the inferior (which are called via function pointers), |
| 926 | find_function_addr uses this function to get the function address |
| 927 | from a function pointer. */ |
| 928 | |
| 929 | /* If ADDR points at what is clearly a function descriptor, transform |
| 930 | it into the address of the corresponding function. Be |
| 931 | conservative, otherwize GDB will do the transformation on any |
| 932 | random addresses such as occures when there is no symbol table. */ |
| 933 | |
| 934 | static CORE_ADDR |
| 935 | ppc64_linux_convert_from_func_ptr_addr (struct gdbarch *gdbarch, |
| 936 | CORE_ADDR addr, |
| 937 | struct target_ops *targ) |
| 938 | { |
| 939 | struct section_table *s = target_section_by_addr (targ, addr); |
| 940 | |
| 941 | /* Check if ADDR points to a function descriptor. */ |
| 942 | if (s && strcmp (s->the_bfd_section->name, ".opd") == 0) |
| 943 | return get_target_memory_unsigned (targ, addr, 8); |
| 944 | |
| 945 | return addr; |
| 946 | } |
| 947 | |
| 948 | |
| 949 | enum { |
| 950 | ELF_NGREG = 48, |
| 951 | ELF_NFPREG = 33, |
| 952 | ELF_NVRREG = 33 |
| 953 | }; |
| 954 | |
| 955 | enum { |
| 956 | ELF_GREGSET_SIZE = (ELF_NGREG * 4), |
| 957 | ELF_FPREGSET_SIZE = (ELF_NFPREG * 8) |
| 958 | }; |
| 959 | |
| 960 | void |
| 961 | ppc_linux_supply_gregset (char *buf) |
| 962 | { |
| 963 | int regi; |
| 964 | struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); |
| 965 | |
| 966 | for (regi = 0; regi < 32; regi++) |
| 967 | supply_register (regi, buf + 4 * regi); |
| 968 | |
| 969 | supply_register (PC_REGNUM, buf + 4 * PPC_LINUX_PT_NIP); |
| 970 | supply_register (tdep->ppc_lr_regnum, buf + 4 * PPC_LINUX_PT_LNK); |
| 971 | supply_register (tdep->ppc_cr_regnum, buf + 4 * PPC_LINUX_PT_CCR); |
| 972 | supply_register (tdep->ppc_xer_regnum, buf + 4 * PPC_LINUX_PT_XER); |
| 973 | supply_register (tdep->ppc_ctr_regnum, buf + 4 * PPC_LINUX_PT_CTR); |
| 974 | if (tdep->ppc_mq_regnum != -1) |
| 975 | supply_register (tdep->ppc_mq_regnum, buf + 4 * PPC_LINUX_PT_MQ); |
| 976 | supply_register (tdep->ppc_ps_regnum, buf + 4 * PPC_LINUX_PT_MSR); |
| 977 | } |
| 978 | |
| 979 | void |
| 980 | ppc_linux_supply_fpregset (char *buf) |
| 981 | { |
| 982 | int regi; |
| 983 | struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch); |
| 984 | |
| 985 | for (regi = 0; regi < 32; regi++) |
| 986 | supply_register (FP0_REGNUM + regi, buf + 8 * regi); |
| 987 | |
| 988 | /* The FPSCR is stored in the low order word of the last doubleword in the |
| 989 | fpregset. */ |
| 990 | supply_register (tdep->ppc_fpscr_regnum, buf + 8 * 32 + 4); |
| 991 | } |
| 992 | |
| 993 | /* |
| 994 | Use a local version of this function to get the correct types for regsets. |
| 995 | */ |
| 996 | |
| 997 | static void |
| 998 | fetch_core_registers (char *core_reg_sect, |
| 999 | unsigned core_reg_size, |
| 1000 | int which, |
| 1001 | CORE_ADDR reg_addr) |
| 1002 | { |
| 1003 | if (which == 0) |
| 1004 | { |
| 1005 | if (core_reg_size == ELF_GREGSET_SIZE) |
| 1006 | ppc_linux_supply_gregset (core_reg_sect); |
| 1007 | else |
| 1008 | warning ("wrong size gregset struct in core file"); |
| 1009 | } |
| 1010 | else if (which == 2) |
| 1011 | { |
| 1012 | if (core_reg_size == ELF_FPREGSET_SIZE) |
| 1013 | ppc_linux_supply_fpregset (core_reg_sect); |
| 1014 | else |
| 1015 | warning ("wrong size fpregset struct in core file"); |
| 1016 | } |
| 1017 | } |
| 1018 | |
| 1019 | /* Register that we are able to handle ELF file formats using standard |
| 1020 | procfs "regset" structures. */ |
| 1021 | |
| 1022 | static struct core_fns ppc_linux_regset_core_fns = |
| 1023 | { |
| 1024 | bfd_target_elf_flavour, /* core_flavour */ |
| 1025 | default_check_format, /* check_format */ |
| 1026 | default_core_sniffer, /* core_sniffer */ |
| 1027 | fetch_core_registers, /* core_read_registers */ |
| 1028 | NULL /* next */ |
| 1029 | }; |
| 1030 | |
| 1031 | static void |
| 1032 | ppc_linux_init_abi (struct gdbarch_info info, |
| 1033 | struct gdbarch *gdbarch) |
| 1034 | { |
| 1035 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 1036 | |
| 1037 | if (tdep->wordsize == 4) |
| 1038 | { |
| 1039 | /* Until November 2001, gcc did not comply with the 32 bit SysV |
| 1040 | R4 ABI requirement that structures less than or equal to 8 |
| 1041 | bytes should be returned in registers. Instead GCC was using |
| 1042 | the the AIX/PowerOpen ABI - everything returned in memory |
| 1043 | (well ignoring vectors that is). When this was corrected, it |
| 1044 | wasn't fixed for GNU/Linux native platform. Use the |
| 1045 | PowerOpen struct convention. */ |
| 1046 | set_gdbarch_use_struct_convention (gdbarch, ppc_linux_use_struct_convention); |
| 1047 | |
| 1048 | /* Note: kevinb/2002-04-12: See note in rs6000_gdbarch_init regarding |
| 1049 | *_push_arguments(). The same remarks hold for the methods below. */ |
| 1050 | set_gdbarch_frameless_function_invocation (gdbarch, |
| 1051 | ppc_linux_frameless_function_invocation); |
| 1052 | set_gdbarch_deprecated_frame_chain (gdbarch, ppc_linux_frame_chain); |
| 1053 | set_gdbarch_deprecated_frame_saved_pc (gdbarch, ppc_linux_frame_saved_pc); |
| 1054 | |
| 1055 | set_gdbarch_deprecated_frame_init_saved_regs (gdbarch, |
| 1056 | ppc_linux_frame_init_saved_regs); |
| 1057 | set_gdbarch_deprecated_init_extra_frame_info (gdbarch, |
| 1058 | ppc_linux_init_extra_frame_info); |
| 1059 | |
| 1060 | set_gdbarch_memory_remove_breakpoint (gdbarch, |
| 1061 | ppc_linux_memory_remove_breakpoint); |
| 1062 | /* Shared library handling. */ |
| 1063 | set_gdbarch_in_solib_call_trampoline (gdbarch, in_plt_section); |
| 1064 | set_gdbarch_skip_trampoline_code (gdbarch, |
| 1065 | ppc_linux_skip_trampoline_code); |
| 1066 | set_solib_svr4_fetch_link_map_offsets |
| 1067 | (gdbarch, ppc_linux_svr4_fetch_link_map_offsets); |
| 1068 | } |
| 1069 | |
| 1070 | if (tdep->wordsize == 8) |
| 1071 | { |
| 1072 | /* Handle PPC64 GNU/Linux function pointers (which are really |
| 1073 | function descriptors). */ |
| 1074 | set_gdbarch_convert_from_func_ptr_addr |
| 1075 | (gdbarch, ppc64_linux_convert_from_func_ptr_addr); |
| 1076 | |
| 1077 | set_gdbarch_in_solib_call_trampoline |
| 1078 | (gdbarch, ppc64_in_solib_call_trampoline); |
| 1079 | set_gdbarch_skip_trampoline_code (gdbarch, ppc64_skip_trampoline_code); |
| 1080 | } |
| 1081 | } |
| 1082 | |
| 1083 | void |
| 1084 | _initialize_ppc_linux_tdep (void) |
| 1085 | { |
| 1086 | gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_LINUX, |
| 1087 | ppc_linux_init_abi); |
| 1088 | add_core_fns (&ppc_linux_regset_core_fns); |
| 1089 | } |