| 1 | /* Target-dependent code for GNU/Linux running on PA-RISC, for GDB. |
| 2 | |
| 3 | Copyright (C) 2004, 2006 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., 51 Franklin Street, Fifth Floor, |
| 20 | Boston, MA 02110-1301, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "gdbcore.h" |
| 24 | #include "osabi.h" |
| 25 | #include "target.h" |
| 26 | #include "objfiles.h" |
| 27 | #include "solib-svr4.h" |
| 28 | #include "glibc-tdep.h" |
| 29 | #include "frame-unwind.h" |
| 30 | #include "trad-frame.h" |
| 31 | #include "dwarf2-frame.h" |
| 32 | #include "value.h" |
| 33 | #include "hppa-tdep.h" |
| 34 | |
| 35 | #include "elf/common.h" |
| 36 | |
| 37 | #if 0 |
| 38 | /* Convert DWARF register number REG to the appropriate register |
| 39 | number used by GDB. */ |
| 40 | static int |
| 41 | hppa_dwarf_reg_to_regnum (int reg) |
| 42 | { |
| 43 | /* registers 0 - 31 are the same in both sets */ |
| 44 | if (reg < 32) |
| 45 | return reg; |
| 46 | |
| 47 | /* dwarf regs 32 to 85 are fpregs 4 - 31 */ |
| 48 | if (reg >= 32 && reg <= 85) |
| 49 | return HPPA_FP4_REGNUM + (reg - 32); |
| 50 | |
| 51 | warning (_("Unmapped DWARF Register #%d encountered."), reg); |
| 52 | return -1; |
| 53 | } |
| 54 | #endif |
| 55 | |
| 56 | static void |
| 57 | hppa_linux_target_write_pc (CORE_ADDR v, ptid_t ptid) |
| 58 | { |
| 59 | /* Probably this should be done by the kernel, but it isn't. */ |
| 60 | write_register_pid (HPPA_PCOQ_HEAD_REGNUM, v | 0x3, ptid); |
| 61 | write_register_pid (HPPA_PCOQ_TAIL_REGNUM, (v + 4) | 0x3, ptid); |
| 62 | } |
| 63 | |
| 64 | /* An instruction to match. */ |
| 65 | struct insn_pattern |
| 66 | { |
| 67 | unsigned int data; /* See if it matches this.... */ |
| 68 | unsigned int mask; /* ... with this mask. */ |
| 69 | }; |
| 70 | |
| 71 | static struct insn_pattern hppa_sigtramp[] = { |
| 72 | /* ldi 0, %r25 or ldi 1, %r25 */ |
| 73 | { 0x34190000, 0xfffffffd }, |
| 74 | /* ldi __NR_rt_sigreturn, %r20 */ |
| 75 | { 0x3414015a, 0xffffffff }, |
| 76 | /* be,l 0x100(%sr2, %r0), %sr0, %r31 */ |
| 77 | { 0xe4008200, 0xffffffff }, |
| 78 | /* nop */ |
| 79 | { 0x08000240, 0xffffffff }, |
| 80 | { 0, 0 } |
| 81 | }; |
| 82 | |
| 83 | #define HPPA_MAX_INSN_PATTERN_LEN (4) |
| 84 | |
| 85 | /* Return non-zero if the instructions at PC match the series |
| 86 | described in PATTERN, or zero otherwise. PATTERN is an array of |
| 87 | 'struct insn_pattern' objects, terminated by an entry whose mask is |
| 88 | zero. |
| 89 | |
| 90 | When the match is successful, fill INSN[i] with what PATTERN[i] |
| 91 | matched. */ |
| 92 | static int |
| 93 | insns_match_pattern (CORE_ADDR pc, |
| 94 | struct insn_pattern *pattern, |
| 95 | unsigned int *insn) |
| 96 | { |
| 97 | int i; |
| 98 | CORE_ADDR npc = pc; |
| 99 | |
| 100 | for (i = 0; pattern[i].mask; i++) |
| 101 | { |
| 102 | char buf[4]; |
| 103 | |
| 104 | deprecated_read_memory_nobpt (npc, buf, 4); |
| 105 | insn[i] = extract_unsigned_integer (buf, 4); |
| 106 | if ((insn[i] & pattern[i].mask) == pattern[i].data) |
| 107 | npc += 4; |
| 108 | else |
| 109 | return 0; |
| 110 | } |
| 111 | return 1; |
| 112 | } |
| 113 | |
| 114 | /* Signal frames. */ |
| 115 | |
| 116 | /* (This is derived from MD_FALLBACK_FRAME_STATE_FOR in gcc.) |
| 117 | |
| 118 | Unfortunately, because of various bugs and changes to the kernel, |
| 119 | we have several cases to deal with. |
| 120 | |
| 121 | In 2.4, the signal trampoline is 4 bytes, and pc should point directly at |
| 122 | the beginning of the trampoline and struct rt_sigframe. |
| 123 | |
| 124 | In <= 2.6.5-rc2-pa3, the signal trampoline is 9 bytes, and pc points at |
| 125 | the 4th word in the trampoline structure. This is wrong, it should point |
| 126 | at the 5th word. This is fixed in 2.6.5-rc2-pa4. |
| 127 | |
| 128 | To detect these cases, we first take pc, align it to 64-bytes |
| 129 | to get the beginning of the signal frame, and then check offsets 0, 4 |
| 130 | and 5 to see if we found the beginning of the trampoline. This will |
| 131 | tell us how to locate the sigcontext structure. |
| 132 | |
| 133 | Note that with a 2.4 64-bit kernel, the signal context is not properly |
| 134 | passed back to userspace so the unwind will not work correctly. */ |
| 135 | static CORE_ADDR |
| 136 | hppa_linux_sigtramp_find_sigcontext (CORE_ADDR pc) |
| 137 | { |
| 138 | unsigned int dummy[HPPA_MAX_INSN_PATTERN_LEN]; |
| 139 | int offs = 0; |
| 140 | int try; |
| 141 | /* offsets to try to find the trampoline */ |
| 142 | static int pcoffs[] = { 0, 4*4, 5*4 }; |
| 143 | /* offsets to the rt_sigframe structure */ |
| 144 | static int sfoffs[] = { 4*4, 10*4, 10*4 }; |
| 145 | CORE_ADDR sp; |
| 146 | |
| 147 | /* Most of the time, this will be correct. The one case when this will |
| 148 | fail is if the user defined an alternate stack, in which case the |
| 149 | beginning of the stack will not be align_down (pc, 64). */ |
| 150 | sp = align_down (pc, 64); |
| 151 | |
| 152 | /* rt_sigreturn trampoline: |
| 153 | 3419000x ldi 0, %r25 or ldi 1, %r25 (x = 0 or 2) |
| 154 | 3414015a ldi __NR_rt_sigreturn, %r20 |
| 155 | e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31 |
| 156 | 08000240 nop */ |
| 157 | |
| 158 | for (try = 0; try < ARRAY_SIZE (pcoffs); try++) |
| 159 | { |
| 160 | if (insns_match_pattern (sp + pcoffs[try], hppa_sigtramp, dummy)) |
| 161 | { |
| 162 | offs = sfoffs[try]; |
| 163 | break; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | if (offs == 0) |
| 168 | { |
| 169 | if (insns_match_pattern (pc, hppa_sigtramp, dummy)) |
| 170 | { |
| 171 | /* sigaltstack case: we have no way of knowing which offset to |
| 172 | use in this case; default to new kernel handling. If this is |
| 173 | wrong the unwinding will fail. */ |
| 174 | try = 2; |
| 175 | sp = pc - pcoffs[try]; |
| 176 | } |
| 177 | else |
| 178 | { |
| 179 | return 0; |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | /* sp + sfoffs[try] points to a struct rt_sigframe, which contains |
| 184 | a struct siginfo and a struct ucontext. struct ucontext contains |
| 185 | a struct sigcontext. Return an offset to this sigcontext here. Too |
| 186 | bad we cannot include system specific headers :-(. |
| 187 | sizeof(struct siginfo) == 128 |
| 188 | offsetof(struct ucontext, uc_mcontext) == 24. */ |
| 189 | return sp + sfoffs[try] + 128 + 24; |
| 190 | } |
| 191 | |
| 192 | struct hppa_linux_sigtramp_unwind_cache |
| 193 | { |
| 194 | CORE_ADDR base; |
| 195 | struct trad_frame_saved_reg *saved_regs; |
| 196 | }; |
| 197 | |
| 198 | static struct hppa_linux_sigtramp_unwind_cache * |
| 199 | hppa_linux_sigtramp_frame_unwind_cache (struct frame_info *next_frame, |
| 200 | void **this_cache) |
| 201 | { |
| 202 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
| 203 | struct hppa_linux_sigtramp_unwind_cache *info; |
| 204 | CORE_ADDR pc, scptr; |
| 205 | int i; |
| 206 | |
| 207 | if (*this_cache) |
| 208 | return *this_cache; |
| 209 | |
| 210 | info = FRAME_OBSTACK_ZALLOC (struct hppa_linux_sigtramp_unwind_cache); |
| 211 | *this_cache = info; |
| 212 | info->saved_regs = trad_frame_alloc_saved_regs (next_frame); |
| 213 | |
| 214 | pc = frame_pc_unwind (next_frame); |
| 215 | scptr = hppa_linux_sigtramp_find_sigcontext (pc); |
| 216 | |
| 217 | /* structure of struct sigcontext: |
| 218 | |
| 219 | struct sigcontext { |
| 220 | unsigned long sc_flags; |
| 221 | unsigned long sc_gr[32]; |
| 222 | unsigned long long sc_fr[32]; |
| 223 | unsigned long sc_iasq[2]; |
| 224 | unsigned long sc_iaoq[2]; |
| 225 | unsigned long sc_sar; */ |
| 226 | |
| 227 | /* Skip sc_flags. */ |
| 228 | scptr += 4; |
| 229 | |
| 230 | /* GR[0] is the psw, we don't restore that. */ |
| 231 | scptr += 4; |
| 232 | |
| 233 | /* General registers. */ |
| 234 | for (i = 1; i < 32; i++) |
| 235 | { |
| 236 | info->saved_regs[HPPA_R0_REGNUM + i].addr = scptr; |
| 237 | scptr += 4; |
| 238 | } |
| 239 | |
| 240 | /* Pad. */ |
| 241 | scptr += 4; |
| 242 | |
| 243 | /* FP regs; FP0-3 are not restored. */ |
| 244 | scptr += (8 * 4); |
| 245 | |
| 246 | for (i = 4; i < 32; i++) |
| 247 | { |
| 248 | info->saved_regs[HPPA_FP0_REGNUM + (i * 2)].addr = scptr; |
| 249 | scptr += 4; |
| 250 | info->saved_regs[HPPA_FP0_REGNUM + (i * 2) + 1].addr = scptr; |
| 251 | scptr += 4; |
| 252 | } |
| 253 | |
| 254 | /* IASQ/IAOQ. */ |
| 255 | info->saved_regs[HPPA_PCSQ_HEAD_REGNUM].addr = scptr; |
| 256 | scptr += 4; |
| 257 | info->saved_regs[HPPA_PCSQ_TAIL_REGNUM].addr = scptr; |
| 258 | scptr += 4; |
| 259 | |
| 260 | info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].addr = scptr; |
| 261 | scptr += 4; |
| 262 | info->saved_regs[HPPA_PCOQ_TAIL_REGNUM].addr = scptr; |
| 263 | scptr += 4; |
| 264 | |
| 265 | info->base = frame_unwind_register_unsigned (next_frame, HPPA_SP_REGNUM); |
| 266 | |
| 267 | return info; |
| 268 | } |
| 269 | |
| 270 | static void |
| 271 | hppa_linux_sigtramp_frame_this_id (struct frame_info *next_frame, |
| 272 | void **this_prologue_cache, |
| 273 | struct frame_id *this_id) |
| 274 | { |
| 275 | struct hppa_linux_sigtramp_unwind_cache *info |
| 276 | = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache); |
| 277 | *this_id = frame_id_build (info->base, frame_pc_unwind (next_frame)); |
| 278 | } |
| 279 | |
| 280 | static void |
| 281 | hppa_linux_sigtramp_frame_prev_register (struct frame_info *next_frame, |
| 282 | void **this_prologue_cache, |
| 283 | int regnum, int *optimizedp, |
| 284 | enum lval_type *lvalp, |
| 285 | CORE_ADDR *addrp, |
| 286 | int *realnump, gdb_byte *valuep) |
| 287 | { |
| 288 | struct hppa_linux_sigtramp_unwind_cache *info |
| 289 | = hppa_linux_sigtramp_frame_unwind_cache (next_frame, this_prologue_cache); |
| 290 | hppa_frame_prev_register_helper (next_frame, info->saved_regs, regnum, |
| 291 | optimizedp, lvalp, addrp, realnump, valuep); |
| 292 | } |
| 293 | |
| 294 | static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = { |
| 295 | SIGTRAMP_FRAME, |
| 296 | hppa_linux_sigtramp_frame_this_id, |
| 297 | hppa_linux_sigtramp_frame_prev_register |
| 298 | }; |
| 299 | |
| 300 | /* hppa-linux always uses "new-style" rt-signals. The signal handler's return |
| 301 | address should point to a signal trampoline on the stack. The signal |
| 302 | trampoline is embedded in a rt_sigframe structure that is aligned on |
| 303 | the stack. We take advantage of the fact that sp must be 64-byte aligned, |
| 304 | and the trampoline is small, so by rounding down the trampoline address |
| 305 | we can find the beginning of the struct rt_sigframe. */ |
| 306 | static const struct frame_unwind * |
| 307 | hppa_linux_sigtramp_unwind_sniffer (struct frame_info *next_frame) |
| 308 | { |
| 309 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
| 310 | |
| 311 | if (hppa_linux_sigtramp_find_sigcontext (pc)) |
| 312 | return &hppa_linux_sigtramp_frame_unwind; |
| 313 | |
| 314 | return NULL; |
| 315 | } |
| 316 | |
| 317 | /* Attempt to find (and return) the global pointer for the given |
| 318 | function. |
| 319 | |
| 320 | This is a rather nasty bit of code searchs for the .dynamic section |
| 321 | in the objfile corresponding to the pc of the function we're trying |
| 322 | to call. Once it finds the addresses at which the .dynamic section |
| 323 | lives in the child process, it scans the Elf32_Dyn entries for a |
| 324 | DT_PLTGOT tag. If it finds one of these, the corresponding |
| 325 | d_un.d_ptr value is the global pointer. */ |
| 326 | |
| 327 | static CORE_ADDR |
| 328 | hppa_linux_find_global_pointer (struct value *function) |
| 329 | { |
| 330 | struct obj_section *faddr_sect; |
| 331 | CORE_ADDR faddr; |
| 332 | |
| 333 | faddr = value_as_address (function); |
| 334 | |
| 335 | /* Is this a plabel? If so, dereference it to get the gp value. */ |
| 336 | if (faddr & 2) |
| 337 | { |
| 338 | int status; |
| 339 | char buf[4]; |
| 340 | |
| 341 | faddr &= ~3; |
| 342 | |
| 343 | status = target_read_memory (faddr + 4, buf, sizeof (buf)); |
| 344 | if (status == 0) |
| 345 | return extract_unsigned_integer (buf, sizeof (buf)); |
| 346 | } |
| 347 | |
| 348 | /* If the address is in the plt section, then the real function hasn't |
| 349 | yet been fixed up by the linker so we cannot determine the gp of |
| 350 | that function. */ |
| 351 | if (in_plt_section (faddr, NULL)) |
| 352 | return 0; |
| 353 | |
| 354 | faddr_sect = find_pc_section (faddr); |
| 355 | if (faddr_sect != NULL) |
| 356 | { |
| 357 | struct obj_section *osect; |
| 358 | |
| 359 | ALL_OBJFILE_OSECTIONS (faddr_sect->objfile, osect) |
| 360 | { |
| 361 | if (strcmp (osect->the_bfd_section->name, ".dynamic") == 0) |
| 362 | break; |
| 363 | } |
| 364 | |
| 365 | if (osect < faddr_sect->objfile->sections_end) |
| 366 | { |
| 367 | CORE_ADDR addr; |
| 368 | |
| 369 | addr = osect->addr; |
| 370 | while (addr < osect->endaddr) |
| 371 | { |
| 372 | int status; |
| 373 | LONGEST tag; |
| 374 | char buf[4]; |
| 375 | |
| 376 | status = target_read_memory (addr, buf, sizeof (buf)); |
| 377 | if (status != 0) |
| 378 | break; |
| 379 | tag = extract_signed_integer (buf, sizeof (buf)); |
| 380 | |
| 381 | if (tag == DT_PLTGOT) |
| 382 | { |
| 383 | CORE_ADDR global_pointer; |
| 384 | |
| 385 | status = target_read_memory (addr + 4, buf, sizeof (buf)); |
| 386 | if (status != 0) |
| 387 | break; |
| 388 | global_pointer = extract_unsigned_integer (buf, sizeof (buf)); |
| 389 | |
| 390 | /* The payoff... */ |
| 391 | return global_pointer; |
| 392 | } |
| 393 | |
| 394 | if (tag == DT_NULL) |
| 395 | break; |
| 396 | |
| 397 | addr += 8; |
| 398 | } |
| 399 | } |
| 400 | } |
| 401 | return 0; |
| 402 | } |
| 403 | |
| 404 | /* Forward declarations. */ |
| 405 | extern initialize_file_ftype _initialize_hppa_linux_tdep; |
| 406 | |
| 407 | static void |
| 408 | hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 409 | { |
| 410 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 411 | |
| 412 | /* GNU/Linux is always ELF. */ |
| 413 | tdep->is_elf = 1; |
| 414 | |
| 415 | tdep->find_global_pointer = hppa_linux_find_global_pointer; |
| 416 | |
| 417 | set_gdbarch_write_pc (gdbarch, hppa_linux_target_write_pc); |
| 418 | |
| 419 | frame_unwind_append_sniffer (gdbarch, hppa_linux_sigtramp_unwind_sniffer); |
| 420 | |
| 421 | /* GNU/Linux uses SVR4-style shared libraries. */ |
| 422 | set_solib_svr4_fetch_link_map_offsets |
| 423 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
| 424 | |
| 425 | tdep->in_solib_call_trampoline = hppa_in_solib_call_trampoline; |
| 426 | set_gdbarch_skip_trampoline_code (gdbarch, hppa_skip_trampoline_code); |
| 427 | |
| 428 | /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ |
| 429 | set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); |
| 430 | |
| 431 | /* On hppa-linux, currently, sizeof(long double) == 8. There has been |
| 432 | some discussions to support 128-bit long double, but it requires some |
| 433 | more work in gcc and glibc first. */ |
| 434 | set_gdbarch_long_double_bit (gdbarch, 64); |
| 435 | |
| 436 | #if 0 |
| 437 | /* Dwarf-2 unwinding support. Not yet working. */ |
| 438 | set_gdbarch_dwarf_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum); |
| 439 | set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum); |
| 440 | frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer); |
| 441 | frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer); |
| 442 | #endif |
| 443 | |
| 444 | /* Enable TLS support. */ |
| 445 | set_gdbarch_fetch_tls_load_module_address (gdbarch, |
| 446 | svr4_fetch_objfile_link_map); |
| 447 | } |
| 448 | |
| 449 | void |
| 450 | _initialize_hppa_linux_tdep (void) |
| 451 | { |
| 452 | gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX, hppa_linux_init_abi); |
| 453 | } |