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, 2009, 2010, 2011
   4    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 3 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, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdbcore.h"
  23 #include "osabi.h"
  24 #include "target.h"
  25 #include "objfiles.h"
  26 #include "solib-svr4.h"
  27 #include "glibc-tdep.h"
  28 #include "frame-unwind.h"
  29 #include "trad-frame.h"
  30 #include "dwarf2-frame.h"
  31 #include "value.h"
  32 #include "regset.h"
  33 #include "regcache.h"
  34 #include "hppa-tdep.h"
  35 #include "linux-tdep.h"
  36 #include "elf/common.h"
  37
  38 /* Map DWARF DBX register numbers to GDB register numbers.  */
  39 static int
  40 hppa_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
  41 {
  42   /* The general registers and the sar are the same in both sets.  */
  43   if (reg <= 32)
  44     return reg;
  45
  46   /* fr4-fr31 (left and right halves) are mapped from 72.  */
  47   if (reg >= 72 && reg <= 72 + 28 * 2)
  48     return HPPA_FP4_REGNUM + (reg - 72);
  49
  50   warning (_("Unmapped DWARF DBX Register #%d encountered."), reg);
  51   return -1;
  52 }
  53
  54 static void
  55 hppa_linux_target_write_pc (struct regcache *regcache, CORE_ADDR v)
  56 {
  57   /* Probably this should be done by the kernel, but it isn't.  */
  58   regcache_cooked_write_unsigned (regcache, HPPA_PCOQ_HEAD_REGNUM, v | 0x3);
  59   regcache_cooked_write_unsigned (regcache,
  60                                   HPPA_PCOQ_TAIL_REGNUM, (v + 4) | 0x3);
  61 }
  62
  63 /* An instruction to match.  */
  64 struct insn_pattern
  65 {
  66   unsigned int data;            /* See if it matches this....  */
  67   unsigned int mask;            /* ... with this mask.  */
  68 };
  69
  70 static struct insn_pattern hppa_sigtramp[] = {
  71   /* ldi 0, %r25 or ldi 1, %r25 */
  72   { 0x34190000, 0xfffffffd },
  73   /* ldi __NR_rt_sigreturn, %r20 */
  74   { 0x3414015a, 0xffffffff },
  75   /* be,l 0x100(%sr2, %r0), %sr0, %r31 */
  76   { 0xe4008200, 0xffffffff },
  77   /* nop */
  78   { 0x08000240, 0xffffffff },
  79   { 0, 0 }
  80 };
  81
  82 #define HPPA_MAX_INSN_PATTERN_LEN (4)
  83
  84 /* Return non-zero if the instructions at PC match the series
  85    described in PATTERN, or zero otherwise.  PATTERN is an array of
  86    'struct insn_pattern' objects, terminated by an entry whose mask is
  87    zero.
  88
  89    When the match is successful, fill INSN[i] with what PATTERN[i]
  90    matched.  */
  91 static int
  92 insns_match_pattern (struct gdbarch *gdbarch, CORE_ADDR pc,
  93                      struct insn_pattern *pattern,
  94                      unsigned int *insn)
  95 {
  96   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  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, byte_order);
 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 (struct gdbarch *gdbarch, 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 (gdbarch, sp + pcoffs[try],
 161                                hppa_sigtramp, dummy))
 162         {
 163           offs = sfoffs[try];
 164           break;
 165         }
 166     }
 167
 168   if (offs == 0)
 169     {
 170       if (insns_match_pattern (gdbarch, pc, hppa_sigtramp, dummy))
 171         {
 172           /* sigaltstack case: we have no way of knowing which offset to
 173              use in this case; default to new kernel handling.  If this is
 174              wrong the unwinding will fail.  */
 175           try = 2;
 176           sp = pc - pcoffs[try];
 177         }
 178       else
 179       {
 180         return 0;
 181       }
 182     }
 183
 184   /* sp + sfoffs[try] points to a struct rt_sigframe, which contains
 185      a struct siginfo and a struct ucontext.  struct ucontext contains
 186      a struct sigcontext.  Return an offset to this sigcontext here.  Too
 187      bad we cannot include system specific headers :-(.
 188      sizeof(struct siginfo) == 128
 189      offsetof(struct ucontext, uc_mcontext) == 24.  */
 190   return sp + sfoffs[try] + 128 + 24;
 191 }
 192
 193 struct hppa_linux_sigtramp_unwind_cache
 194 {
 195   CORE_ADDR base;
 196   struct trad_frame_saved_reg *saved_regs;
 197 };
 198
 199 static struct hppa_linux_sigtramp_unwind_cache *
 200 hppa_linux_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
 201                                         void **this_cache)
 202 {
 203   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 204   struct hppa_linux_sigtramp_unwind_cache *info;
 205   CORE_ADDR pc, scptr;
 206   int i;
 207
 208   if (*this_cache)
 209     return *this_cache;
 210
 211   info = FRAME_OBSTACK_ZALLOC (struct hppa_linux_sigtramp_unwind_cache);
 212   *this_cache = info;
 213   info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
 214
 215   pc = get_frame_pc (this_frame);
 216   scptr = hppa_linux_sigtramp_find_sigcontext (gdbarch, pc);
 217
 218   /* structure of struct sigcontext:
 219
 220      struct sigcontext {
 221         unsigned long sc_flags;
 222         unsigned long sc_gr[32];
 223         unsigned long long sc_fr[32];
 224         unsigned long sc_iasq[2];
 225         unsigned long sc_iaoq[2];
 226         unsigned long sc_sar;           */
 227
 228   /* Skip sc_flags.  */
 229   scptr += 4;
 230
 231   /* GR[0] is the psw.  */
 232   info->saved_regs[HPPA_IPSW_REGNUM].addr = scptr;
 233   scptr += 4;
 234
 235   /* General registers.  */
 236   for (i = 1; i < 32; i++)
 237     {
 238       info->saved_regs[HPPA_R0_REGNUM + i].addr = scptr;
 239       scptr += 4;
 240     }
 241
 242   /* Pad to long long boundary.  */
 243   scptr += 4;
 244
 245   /* FP regs; FP0-3 are not restored.  */
 246   scptr += (8 * 4);
 247
 248   for (i = 4; i < 32; i++)
 249     {
 250       info->saved_regs[HPPA_FP0_REGNUM + (i * 2)].addr = scptr;
 251       scptr += 4;
 252       info->saved_regs[HPPA_FP0_REGNUM + (i * 2) + 1].addr = scptr;
 253       scptr += 4;
 254     }
 255
 256   /* IASQ/IAOQ.  */
 257   info->saved_regs[HPPA_PCSQ_HEAD_REGNUM].addr = scptr;
 258   scptr += 4;
 259   info->saved_regs[HPPA_PCSQ_TAIL_REGNUM].addr = scptr;
 260   scptr += 4;
 261
 262   info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].addr = scptr;
 263   scptr += 4;
 264   info->saved_regs[HPPA_PCOQ_TAIL_REGNUM].addr = scptr;
 265   scptr += 4;
 266
 267   info->saved_regs[HPPA_SAR_REGNUM].addr = scptr;
 268
 269   info->base = get_frame_register_unsigned (this_frame, HPPA_SP_REGNUM);
 270
 271   return info;
 272 }
 273
 274 static void
 275 hppa_linux_sigtramp_frame_this_id (struct frame_info *this_frame,
 276                                    void **this_prologue_cache,
 277                                    struct frame_id *this_id)
 278 {
 279   struct hppa_linux_sigtramp_unwind_cache *info
 280     = hppa_linux_sigtramp_frame_unwind_cache (this_frame, this_prologue_cache);
 281   *this_id = frame_id_build (info->base, get_frame_pc (this_frame));
 282 }
 283
 284 static struct value *
 285 hppa_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
 286                                          void **this_prologue_cache,
 287                                          int regnum)
 288 {
 289   struct hppa_linux_sigtramp_unwind_cache *info
 290     = hppa_linux_sigtramp_frame_unwind_cache (this_frame, this_prologue_cache);
 291   return hppa_frame_prev_register_helper (this_frame,
 292                                           info->saved_regs, regnum);
 293 }
 294
 295 /* hppa-linux always uses "new-style" rt-signals.  The signal handler's return
 296    address should point to a signal trampoline on the stack.  The signal
 297    trampoline is embedded in a rt_sigframe structure that is aligned on
 298    the stack.  We take advantage of the fact that sp must be 64-byte aligned,
 299    and the trampoline is small, so by rounding down the trampoline address
 300    we can find the beginning of the struct rt_sigframe.  */
 301 static int
 302 hppa_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 303                                    struct frame_info *this_frame,
 304                                    void **this_prologue_cache)
 305 {
 306   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 307   CORE_ADDR pc = get_frame_pc (this_frame);
 308
 309   if (hppa_linux_sigtramp_find_sigcontext (gdbarch, pc))
 310     return 1;
 311
 312   return 0;
 313 }
 314
 315 static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = {
 316   SIGTRAMP_FRAME,
 317   hppa_linux_sigtramp_frame_this_id,
 318   hppa_linux_sigtramp_frame_prev_register,
 319   NULL,
 320   hppa_linux_sigtramp_frame_sniffer
 321 };
 322
 323 /* Attempt to find (and return) the global pointer for the given
 324    function.
 325
 326    This is a rather nasty bit of code searchs for the .dynamic section
 327    in the objfile corresponding to the pc of the function we're trying
 328    to call.  Once it finds the addresses at which the .dynamic section
 329    lives in the child process, it scans the Elf32_Dyn entries for a
 330    DT_PLTGOT tag.  If it finds one of these, the corresponding
 331    d_un.d_ptr value is the global pointer.  */
 332
 333 static CORE_ADDR
 334 hppa_linux_find_global_pointer (struct gdbarch *gdbarch,
 335                                 struct value *function)
 336 {
 337   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 338   struct obj_section *faddr_sect;
 339   CORE_ADDR faddr;
 340
 341   faddr = value_as_address (function);
 342
 343   /* Is this a plabel? If so, dereference it to get the gp value.  */
 344   if (faddr & 2)
 345     {
 346       int status;
 347       char buf[4];
 348
 349       faddr &= ~3;
 350
 351       status = target_read_memory (faddr + 4, buf, sizeof (buf));
 352       if (status == 0)
 353         return extract_unsigned_integer (buf, sizeof (buf), byte_order);
 354     }
 355
 356   /* If the address is in the plt section, then the real function hasn't
 357      yet been fixed up by the linker so we cannot determine the gp of
 358      that function.  */
 359   if (in_plt_section (faddr, NULL))
 360     return 0;
 361
 362   faddr_sect = find_pc_section (faddr);
 363   if (faddr_sect != NULL)
 364     {
 365       struct obj_section *osect;
 366
 367       ALL_OBJFILE_OSECTIONS (faddr_sect->objfile, osect)
 368         {
 369           if (strcmp (osect->the_bfd_section->name, ".dynamic") == 0)
 370             break;
 371         }
 372
 373       if (osect < faddr_sect->objfile->sections_end)
 374         {
 375           CORE_ADDR addr, endaddr;
 376
 377           addr = obj_section_addr (osect);
 378           endaddr = obj_section_endaddr (osect);
 379
 380           while (addr < endaddr)
 381             {
 382               int status;
 383               LONGEST tag;
 384               char buf[4];
 385
 386               status = target_read_memory (addr, buf, sizeof (buf));
 387               if (status != 0)
 388                 break;
 389               tag = extract_signed_integer (buf, sizeof (buf), byte_order);
 390
 391               if (tag == DT_PLTGOT)
 392                 {
 393                   CORE_ADDR global_pointer;
 394
 395                   status = target_read_memory (addr + 4, buf, sizeof (buf));
 396                   if (status != 0)
 397                     break;
 398                   global_pointer = extract_unsigned_integer (buf, sizeof (buf),
 399                                                              byte_order);
 400                   /* The payoff...  */
 401                   return global_pointer;
 402                 }
 403
 404               if (tag == DT_NULL)
 405                 break;
 406
 407               addr += 8;
 408             }
 409         }
 410     }
 411   return 0;
 412 }
 413 \f
 414 /*
 415  * Registers saved in a coredump:
 416  * gr0..gr31
 417  * sr0..sr7
 418  * iaoq0..iaoq1
 419  * iasq0..iasq1
 420  * sar, iir, isr, ior, ipsw
 421  * cr0, cr24..cr31
 422  * cr8,9,12,13
 423  * cr10, cr15
 424  */
 425
 426 #define GR_REGNUM(_n)   (HPPA_R0_REGNUM+_n)
 427 #define TR_REGNUM(_n)   (HPPA_TR0_REGNUM+_n)
 428 static const int greg_map[] =
 429   {
 430     GR_REGNUM(0), GR_REGNUM(1), GR_REGNUM(2), GR_REGNUM(3),
 431     GR_REGNUM(4), GR_REGNUM(5), GR_REGNUM(6), GR_REGNUM(7),
 432     GR_REGNUM(8), GR_REGNUM(9), GR_REGNUM(10), GR_REGNUM(11),
 433     GR_REGNUM(12), GR_REGNUM(13), GR_REGNUM(14), GR_REGNUM(15),
 434     GR_REGNUM(16), GR_REGNUM(17), GR_REGNUM(18), GR_REGNUM(19),
 435     GR_REGNUM(20), GR_REGNUM(21), GR_REGNUM(22), GR_REGNUM(23),
 436     GR_REGNUM(24), GR_REGNUM(25), GR_REGNUM(26), GR_REGNUM(27),
 437     GR_REGNUM(28), GR_REGNUM(29), GR_REGNUM(30), GR_REGNUM(31),
 438
 439     HPPA_SR4_REGNUM+1, HPPA_SR4_REGNUM+2, HPPA_SR4_REGNUM+3, HPPA_SR4_REGNUM+4,
 440     HPPA_SR4_REGNUM, HPPA_SR4_REGNUM+5, HPPA_SR4_REGNUM+6, HPPA_SR4_REGNUM+7,
 441
 442     HPPA_PCOQ_HEAD_REGNUM, HPPA_PCOQ_TAIL_REGNUM,
 443     HPPA_PCSQ_HEAD_REGNUM, HPPA_PCSQ_TAIL_REGNUM,
 444
 445     HPPA_SAR_REGNUM, HPPA_IIR_REGNUM, HPPA_ISR_REGNUM, HPPA_IOR_REGNUM,
 446     HPPA_IPSW_REGNUM, HPPA_RCR_REGNUM,
 447
 448     TR_REGNUM(0), TR_REGNUM(1), TR_REGNUM(2), TR_REGNUM(3),
 449     TR_REGNUM(4), TR_REGNUM(5), TR_REGNUM(6), TR_REGNUM(7),
 450
 451     HPPA_PID0_REGNUM, HPPA_PID1_REGNUM, HPPA_PID2_REGNUM, HPPA_PID3_REGNUM,
 452     HPPA_CCR_REGNUM, HPPA_EIEM_REGNUM,
 453   };
 454
 455 static void
 456 hppa_linux_supply_regset (const struct regset *regset,
 457                           struct regcache *regcache,
 458                           int regnum, const void *regs, size_t len)
 459 {
 460   struct gdbarch *arch = get_regcache_arch (regcache);
 461   struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
 462   const char *buf = regs;
 463   int i, offset;
 464
 465   offset = 0;
 466   for (i = 0; i < ARRAY_SIZE (greg_map); i++)
 467     {
 468       if (regnum == greg_map[i] || regnum == -1)
 469         regcache_raw_supply (regcache, greg_map[i], buf + offset);
 470
 471       offset += tdep->bytes_per_address;
 472     }
 473 }
 474
 475 static void
 476 hppa_linux_supply_fpregset (const struct regset *regset,
 477                             struct regcache *regcache,
 478                             int regnum, const void *regs, size_t len)
 479 {
 480   const char *buf = regs;
 481   int i, offset;
 482
 483   offset = 0;
 484   for (i = 0; i < 64; i++)
 485     {
 486       if (regnum == HPPA_FP0_REGNUM + i || regnum == -1)
 487         regcache_raw_supply (regcache, HPPA_FP0_REGNUM + i,
 488                              buf + offset);
 489       offset += 4;
 490     }
 491 }
 492
 493 /* HPPA Linux kernel register set.  */
 494 static struct regset hppa_linux_regset =
 495 {
 496   NULL,
 497   hppa_linux_supply_regset
 498 };
 499
 500 static struct regset hppa_linux_fpregset =
 501 {
 502   NULL,
 503   hppa_linux_supply_fpregset
 504 };
 505
 506 static const struct regset *
 507 hppa_linux_regset_from_core_section (struct gdbarch *gdbarch,
 508                                      const char *sect_name,
 509                                      size_t sect_size)
 510 {
 511   if (strcmp (sect_name, ".reg") == 0)
 512     return &hppa_linux_regset;
 513   else if (strcmp (sect_name, ".reg2") == 0)
 514     return &hppa_linux_fpregset;
 515
 516   return NULL;
 517 }
 518 \f
 519
 520 /* Forward declarations.  */
 521 extern initialize_file_ftype _initialize_hppa_linux_tdep;
 522
 523 static void
 524 hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 525 {
 526   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 527
 528   linux_init_abi (info, gdbarch);
 529
 530   /* GNU/Linux is always ELF.  */
 531   tdep->is_elf = 1;
 532
 533   tdep->find_global_pointer = hppa_linux_find_global_pointer;
 534
 535   set_gdbarch_write_pc (gdbarch, hppa_linux_target_write_pc);
 536
 537   frame_unwind_append_unwinder (gdbarch, &hppa_linux_sigtramp_frame_unwind);
 538
 539   /* GNU/Linux uses SVR4-style shared libraries.  */
 540   set_solib_svr4_fetch_link_map_offsets
 541     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 542
 543   tdep->in_solib_call_trampoline = hppa_in_solib_call_trampoline;
 544   set_gdbarch_skip_trampoline_code (gdbarch, hppa_skip_trampoline_code);
 545
 546   /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
 547   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 548
 549   /* On hppa-linux, currently, sizeof(long double) == 8.  There has been
 550      some discussions to support 128-bit long double, but it requires some
 551      more work in gcc and glibc first.  */
 552   set_gdbarch_long_double_bit (gdbarch, 64);
 553
 554   set_gdbarch_regset_from_core_section
 555     (gdbarch, hppa_linux_regset_from_core_section);
 556
 557   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
 558
 559   /* Enable TLS support.  */
 560   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 561                                              svr4_fetch_objfile_link_map);
 562 }
 563
 564 void
 565 _initialize_hppa_linux_tdep (void)
 566 {
 567   gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX,
 568                           hppa_linux_init_abi);
 569   gdbarch_register_osabi (bfd_arch_hppa, bfd_mach_hppa20w,
 570                           GDB_OSABI_LINUX, hppa_linux_init_abi);
 571 }