gdb/hppa-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux running on PA-RISC, for GDB.
   2
   3    Copyright (C) 2004, 2006, 2007, 2008 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 3 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, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "gdbcore.h"
  22 #include "osabi.h"
  23 #include "target.h"
  24 #include "objfiles.h"
  25 #include "solib-svr4.h"
  26 #include "glibc-tdep.h"
  27 #include "frame-unwind.h"
  28 #include "trad-frame.h"
  29 #include "dwarf2-frame.h"
  30 #include "value.h"
  31 #include "regset.h"
  32 #include "regcache.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 (struct regcache *regcache, CORE_ADDR v)
  58 {
  59   /* Probably this should be done by the kernel, but it isn't.  */
  60   regcache_cooked_write_unsigned (regcache, HPPA_PCOQ_HEAD_REGNUM, v | 0x3);
  61   regcache_cooked_write_unsigned (regcache, HPPA_PCOQ_TAIL_REGNUM, (v + 4) | 0x3);
  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       target_read_memory (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 gdbarch *gdbarch, 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 \f
 404 /*
 405  * Registers saved in a coredump:
 406  * gr0..gr31
 407  * sr0..sr7
 408  * iaoq0..iaoq1
 409  * iasq0..iasq1
 410  * sar, iir, isr, ior, ipsw
 411  * cr0, cr24..cr31
 412  * cr8,9,12,13
 413  * cr10, cr15
 414  */
 415
 416 #define GR_REGNUM(_n)   (HPPA_R0_REGNUM+_n)
 417 #define TR_REGNUM(_n)   (HPPA_TR0_REGNUM+_n)
 418 static const int greg_map[] =
 419   {
 420     GR_REGNUM(0), GR_REGNUM(1), GR_REGNUM(2), GR_REGNUM(3),
 421     GR_REGNUM(4), GR_REGNUM(5), GR_REGNUM(6), GR_REGNUM(7),
 422     GR_REGNUM(8), GR_REGNUM(9), GR_REGNUM(10), GR_REGNUM(11),
 423     GR_REGNUM(12), GR_REGNUM(13), GR_REGNUM(14), GR_REGNUM(15),
 424     GR_REGNUM(16), GR_REGNUM(17), GR_REGNUM(18), GR_REGNUM(19),
 425     GR_REGNUM(20), GR_REGNUM(21), GR_REGNUM(22), GR_REGNUM(23),
 426     GR_REGNUM(24), GR_REGNUM(25), GR_REGNUM(26), GR_REGNUM(27),
 427     GR_REGNUM(28), GR_REGNUM(29), GR_REGNUM(30), GR_REGNUM(31),
 428
 429     HPPA_SR4_REGNUM+1, HPPA_SR4_REGNUM+2, HPPA_SR4_REGNUM+3, HPPA_SR4_REGNUM+4,
 430     HPPA_SR4_REGNUM, HPPA_SR4_REGNUM+5, HPPA_SR4_REGNUM+6, HPPA_SR4_REGNUM+7,
 431
 432     HPPA_PCOQ_HEAD_REGNUM, HPPA_PCOQ_TAIL_REGNUM,
 433     HPPA_PCSQ_HEAD_REGNUM, HPPA_PCSQ_TAIL_REGNUM,
 434
 435     HPPA_SAR_REGNUM, HPPA_IIR_REGNUM, HPPA_ISR_REGNUM, HPPA_IOR_REGNUM,
 436     HPPA_IPSW_REGNUM, HPPA_RCR_REGNUM,
 437
 438     TR_REGNUM(0), TR_REGNUM(1), TR_REGNUM(2), TR_REGNUM(3),
 439     TR_REGNUM(4), TR_REGNUM(5), TR_REGNUM(6), TR_REGNUM(7),
 440
 441     HPPA_PID0_REGNUM, HPPA_PID1_REGNUM, HPPA_PID2_REGNUM, HPPA_PID3_REGNUM,
 442     HPPA_CCR_REGNUM, HPPA_EIEM_REGNUM,
 443   };
 444
 445 static void
 446 hppa_linux_supply_regset (const struct regset *regset,
 447                           struct regcache *regcache,
 448                           int regnum, const void *regs, size_t len)
 449 {
 450   struct gdbarch *arch = get_regcache_arch (regcache);
 451   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
 452   const char *buf = regs;
 453   int i, offset;
 454
 455   offset = 0;
 456   for (i = 0; i < ARRAY_SIZE (greg_map); i++)
 457     {
 458       if (regnum == greg_map[i] || regnum == -1)
 459         regcache_raw_supply (regcache, greg_map[i], buf + offset);
 460
 461       offset += tdep->bytes_per_address;
 462     }
 463 }
 464
 465 static void
 466 hppa_linux_supply_fpregset (const struct regset *regset,
 467                             struct regcache *regcache,
 468                             int regnum, const void *regs, size_t len)
 469 {
 470   const char *buf = regs;
 471   int i, offset;
 472
 473   offset = 0;
 474   for (i = 0; i < 31; i++)
 475     {
 476       if (regnum == HPPA_FP0_REGNUM + i || regnum == -1)
 477         regcache_raw_supply (regcache, HPPA_FP0_REGNUM + i,
 478                              buf + offset);
 479       offset += 8;
 480     }
 481 }
 482
 483 /* HPPA Linux kernel register set.  */
 484 static struct regset hppa_linux_regset =
 485 {
 486   NULL,
 487   hppa_linux_supply_regset
 488 };
 489
 490 static struct regset hppa_linux_fpregset =
 491 {
 492   NULL,
 493   hppa_linux_supply_fpregset
 494 };
 495
 496 static const struct regset *
 497 hppa_linux_regset_from_core_section (struct gdbarch *gdbarch,
 498                                      const char *sect_name,
 499                                      size_t sect_size)
 500 {
 501   if (strcmp (sect_name, ".reg") == 0)
 502     return &hppa_linux_regset;
 503   else if (strcmp (sect_name, ".reg2") == 0)
 504     return &hppa_linux_fpregset;
 505
 506   return NULL;
 507 }
 508 \f
 509
 510 /* Forward declarations.  */
 511 extern initialize_file_ftype _initialize_hppa_linux_tdep;
 512
 513 static void
 514 hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 515 {
 516   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 517
 518   /* GNU/Linux is always ELF.  */
 519   tdep->is_elf = 1;
 520
 521   tdep->find_global_pointer = hppa_linux_find_global_pointer;
 522
 523   set_gdbarch_write_pc (gdbarch, hppa_linux_target_write_pc);
 524
 525   frame_unwind_append_sniffer (gdbarch, hppa_linux_sigtramp_unwind_sniffer);
 526
 527   /* GNU/Linux uses SVR4-style shared libraries.  */
 528   set_solib_svr4_fetch_link_map_offsets
 529     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 530
 531   tdep->in_solib_call_trampoline = hppa_in_solib_call_trampoline;
 532   set_gdbarch_skip_trampoline_code (gdbarch, hppa_skip_trampoline_code);
 533
 534   /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
 535   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 536
 537   /* On hppa-linux, currently, sizeof(long double) == 8.  There has been
 538      some discussions to support 128-bit long double, but it requires some
 539      more work in gcc and glibc first.  */
 540   set_gdbarch_long_double_bit (gdbarch, 64);
 541
 542   set_gdbarch_regset_from_core_section
 543     (gdbarch, hppa_linux_regset_from_core_section);
 544
 545 #if 0
 546   /* Dwarf-2 unwinding support.  Not yet working.  */
 547   set_gdbarch_dwarf_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
 548   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
 549   frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
 550   frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer);
 551 #endif
 552
 553   /* Enable TLS support.  */
 554   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 555                                              svr4_fetch_objfile_link_map);
 556 }
 557
 558 void
 559 _initialize_hppa_linux_tdep (void)
 560 {
 561   gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX, hppa_linux_init_abi);
 562   gdbarch_register_osabi (bfd_arch_hppa, bfd_mach_hppa20w, GDB_OSABI_LINUX, hppa_linux_init_abi);
 563 }