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 /* Map DWARF DBX register numbers to GDB register numbers.  */
  38 static int
  39 hppa_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
  40 {
  41   /* The general registers and the sar are the same in both sets.  */
  42   if (reg <= 32)
  43     return reg;
  44
  45   /* fr4-fr31 (left and right halves) are mapped from 72.  */
  46   if (reg >= 72 && reg <= 72 + 28 * 2)
  47     return HPPA_FP4_REGNUM + (reg - 72);
  48
  49   warning (_("Unmapped DWARF DBX Register #%d encountered."), reg);
  50   return -1;
  51 }
  52
  53 static void
  54 hppa_linux_target_write_pc (struct regcache *regcache, CORE_ADDR v)
  55 {
  56   /* Probably this should be done by the kernel, but it isn't.  */
  57   regcache_cooked_write_unsigned (regcache, HPPA_PCOQ_HEAD_REGNUM, v | 0x3);
  58   regcache_cooked_write_unsigned (regcache, HPPA_PCOQ_TAIL_REGNUM, (v + 4) | 0x3);
  59 }
  60
  61 /* An instruction to match.  */
  62 struct insn_pattern
  63 {
  64   unsigned int data;            /* See if it matches this....  */
  65   unsigned int mask;            /* ... with this mask.  */
  66 };
  67
  68 static struct insn_pattern hppa_sigtramp[] = {
  69   /* ldi 0, %r25 or ldi 1, %r25 */
  70   { 0x34190000, 0xfffffffd },
  71   /* ldi __NR_rt_sigreturn, %r20 */
  72   { 0x3414015a, 0xffffffff },
  73   /* be,l 0x100(%sr2, %r0), %sr0, %r31 */
  74   { 0xe4008200, 0xffffffff },
  75   /* nop */
  76   { 0x08000240, 0xffffffff },
  77   { 0, 0 }
  78 };
  79
  80 #define HPPA_MAX_INSN_PATTERN_LEN (4)
  81
  82 /* Return non-zero if the instructions at PC match the series
  83    described in PATTERN, or zero otherwise.  PATTERN is an array of
  84    'struct insn_pattern' objects, terminated by an entry whose mask is
  85    zero.
  86
  87    When the match is successful, fill INSN[i] with what PATTERN[i]
  88    matched.  */
  89 static int
  90 insns_match_pattern (CORE_ADDR pc,
  91                      struct insn_pattern *pattern,
  92                      unsigned int *insn)
  93 {
  94   int i;
  95   CORE_ADDR npc = pc;
  96
  97   for (i = 0; pattern[i].mask; i++)
  98     {
  99       char buf[4];
 100
 101       target_read_memory (npc, buf, 4);
 102       insn[i] = extract_unsigned_integer (buf, 4);
 103       if ((insn[i] & pattern[i].mask) == pattern[i].data)
 104         npc += 4;
 105       else
 106         return 0;
 107     }
 108   return 1;
 109 }
 110
 111 /* Signal frames.  */
 112
 113 /* (This is derived from MD_FALLBACK_FRAME_STATE_FOR in gcc.)
 114
 115    Unfortunately, because of various bugs and changes to the kernel,
 116    we have several cases to deal with.
 117
 118    In 2.4, the signal trampoline is 4 bytes, and pc should point directly at
 119    the beginning of the trampoline and struct rt_sigframe.
 120
 121    In <= 2.6.5-rc2-pa3, the signal trampoline is 9 bytes, and pc points at
 122    the 4th word in the trampoline structure.  This is wrong, it should point
 123    at the 5th word.  This is fixed in 2.6.5-rc2-pa4.
 124
 125    To detect these cases, we first take pc, align it to 64-bytes
 126    to get the beginning of the signal frame, and then check offsets 0, 4
 127    and 5 to see if we found the beginning of the trampoline.  This will
 128    tell us how to locate the sigcontext structure.
 129
 130    Note that with a 2.4 64-bit kernel, the signal context is not properly
 131    passed back to userspace so the unwind will not work correctly.  */
 132 static CORE_ADDR
 133 hppa_linux_sigtramp_find_sigcontext (CORE_ADDR pc)
 134 {
 135   unsigned int dummy[HPPA_MAX_INSN_PATTERN_LEN];
 136   int offs = 0;
 137   int try;
 138   /* offsets to try to find the trampoline */
 139   static int pcoffs[] = { 0, 4*4, 5*4 };
 140   /* offsets to the rt_sigframe structure */
 141   static int sfoffs[] = { 4*4, 10*4, 10*4 };
 142   CORE_ADDR sp;
 143
 144   /* Most of the time, this will be correct.  The one case when this will
 145      fail is if the user defined an alternate stack, in which case the
 146      beginning of the stack will not be align_down (pc, 64).  */
 147   sp = align_down (pc, 64);
 148
 149   /* rt_sigreturn trampoline:
 150      3419000x ldi 0, %r25 or ldi 1, %r25   (x = 0 or 2)
 151      3414015a ldi __NR_rt_sigreturn, %r20
 152      e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31
 153      08000240 nop  */
 154
 155   for (try = 0; try < ARRAY_SIZE (pcoffs); try++)
 156     {
 157       if (insns_match_pattern (sp + pcoffs[try], hppa_sigtramp, dummy))
 158         {
 159           offs = sfoffs[try];
 160           break;
 161         }
 162     }
 163
 164   if (offs == 0)
 165     {
 166       if (insns_match_pattern (pc, hppa_sigtramp, dummy))
 167         {
 168           /* sigaltstack case: we have no way of knowing which offset to
 169              use in this case; default to new kernel handling. If this is
 170              wrong the unwinding will fail.  */
 171           try = 2;
 172           sp = pc - pcoffs[try];
 173         }
 174       else
 175       {
 176         return 0;
 177       }
 178     }
 179
 180   /* sp + sfoffs[try] points to a struct rt_sigframe, which contains
 181      a struct siginfo and a struct ucontext.  struct ucontext contains
 182      a struct sigcontext. Return an offset to this sigcontext here.  Too
 183      bad we cannot include system specific headers :-(.
 184      sizeof(struct siginfo) == 128
 185      offsetof(struct ucontext, uc_mcontext) == 24.  */
 186   return sp + sfoffs[try] + 128 + 24;
 187 }
 188
 189 struct hppa_linux_sigtramp_unwind_cache
 190 {
 191   CORE_ADDR base;
 192   struct trad_frame_saved_reg *saved_regs;
 193 };
 194
 195 static struct hppa_linux_sigtramp_unwind_cache *
 196 hppa_linux_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
 197                                         void **this_cache)
 198 {
 199   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 200   struct hppa_linux_sigtramp_unwind_cache *info;
 201   CORE_ADDR pc, scptr;
 202   int i;
 203
 204   if (*this_cache)
 205     return *this_cache;
 206
 207   info = FRAME_OBSTACK_ZALLOC (struct hppa_linux_sigtramp_unwind_cache);
 208   *this_cache = info;
 209   info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
 210
 211   pc = get_frame_pc (this_frame);
 212   scptr = hppa_linux_sigtramp_find_sigcontext (pc);
 213
 214   /* structure of struct sigcontext:
 215
 216      struct sigcontext {
 217         unsigned long sc_flags;
 218         unsigned long sc_gr[32];
 219         unsigned long long sc_fr[32];
 220         unsigned long sc_iasq[2];
 221         unsigned long sc_iaoq[2];
 222         unsigned long sc_sar;           */
 223
 224   /* Skip sc_flags.  */
 225   scptr += 4;
 226
 227   /* GR[0] is the psw, we don't restore that.  */
 228   scptr += 4;
 229
 230   /* General registers.  */
 231   for (i = 1; i < 32; i++)
 232     {
 233       info->saved_regs[HPPA_R0_REGNUM + i].addr = scptr;
 234       scptr += 4;
 235     }
 236
 237   /* Pad.  */
 238   scptr += 4;
 239
 240   /* FP regs; FP0-3 are not restored.  */
 241   scptr += (8 * 4);
 242
 243   for (i = 4; i < 32; i++)
 244     {
 245       info->saved_regs[HPPA_FP0_REGNUM + (i * 2)].addr = scptr;
 246       scptr += 4;
 247       info->saved_regs[HPPA_FP0_REGNUM + (i * 2) + 1].addr = scptr;
 248       scptr += 4;
 249     }
 250
 251   /* IASQ/IAOQ. */
 252   info->saved_regs[HPPA_PCSQ_HEAD_REGNUM].addr = scptr;
 253   scptr += 4;
 254   info->saved_regs[HPPA_PCSQ_TAIL_REGNUM].addr = scptr;
 255   scptr += 4;
 256
 257   info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].addr = scptr;
 258   scptr += 4;
 259   info->saved_regs[HPPA_PCOQ_TAIL_REGNUM].addr = scptr;
 260   scptr += 4;
 261
 262   info->base = get_frame_register_unsigned (this_frame, HPPA_SP_REGNUM);
 263
 264   return info;
 265 }
 266
 267 static void
 268 hppa_linux_sigtramp_frame_this_id (struct frame_info *this_frame,
 269                                    void **this_prologue_cache,
 270                                    struct frame_id *this_id)
 271 {
 272   struct hppa_linux_sigtramp_unwind_cache *info
 273     = hppa_linux_sigtramp_frame_unwind_cache (this_frame, this_prologue_cache);
 274   *this_id = frame_id_build (info->base, get_frame_pc (this_frame));
 275 }
 276
 277 static struct value *
 278 hppa_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
 279                                          void **this_prologue_cache,
 280                                          int regnum)
 281 {
 282   struct hppa_linux_sigtramp_unwind_cache *info
 283     = hppa_linux_sigtramp_frame_unwind_cache (this_frame, this_prologue_cache);
 284   return hppa_frame_prev_register_helper (this_frame,
 285                                           info->saved_regs, regnum);
 286 }
 287
 288 /* hppa-linux always uses "new-style" rt-signals.  The signal handler's return
 289    address should point to a signal trampoline on the stack.  The signal
 290    trampoline is embedded in a rt_sigframe structure that is aligned on
 291    the stack.  We take advantage of the fact that sp must be 64-byte aligned,
 292    and the trampoline is small, so by rounding down the trampoline address
 293    we can find the beginning of the struct rt_sigframe.  */
 294 static int
 295 hppa_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 296                                    struct frame_info *this_frame,
 297                                    void **this_prologue_cache)
 298 {
 299   CORE_ADDR pc = get_frame_pc (this_frame);
 300
 301   if (hppa_linux_sigtramp_find_sigcontext (pc))
 302     return 1;
 303
 304   return 0;
 305 }
 306
 307 static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = {
 308   SIGTRAMP_FRAME,
 309   hppa_linux_sigtramp_frame_this_id,
 310   hppa_linux_sigtramp_frame_prev_register,
 311   NULL,
 312   hppa_linux_sigtramp_frame_sniffer
 313 };
 314
 315 /* Attempt to find (and return) the global pointer for the given
 316    function.
 317
 318    This is a rather nasty bit of code searchs for the .dynamic section
 319    in the objfile corresponding to the pc of the function we're trying
 320    to call.  Once it finds the addresses at which the .dynamic section
 321    lives in the child process, it scans the Elf32_Dyn entries for a
 322    DT_PLTGOT tag.  If it finds one of these, the corresponding
 323    d_un.d_ptr value is the global pointer.  */
 324
 325 static CORE_ADDR
 326 hppa_linux_find_global_pointer (struct gdbarch *gdbarch, struct value *function)
 327 {
 328   struct obj_section *faddr_sect;
 329   CORE_ADDR faddr;
 330
 331   faddr = value_as_address (function);
 332
 333   /* Is this a plabel? If so, dereference it to get the gp value.  */
 334   if (faddr & 2)
 335     {
 336       int status;
 337       char buf[4];
 338
 339       faddr &= ~3;
 340
 341       status = target_read_memory (faddr + 4, buf, sizeof (buf));
 342       if (status == 0)
 343         return extract_unsigned_integer (buf, sizeof (buf));
 344     }
 345
 346   /* If the address is in the plt section, then the real function hasn't
 347      yet been fixed up by the linker so we cannot determine the gp of
 348      that function.  */
 349   if (in_plt_section (faddr, NULL))
 350     return 0;
 351
 352   faddr_sect = find_pc_section (faddr);
 353   if (faddr_sect != NULL)
 354     {
 355       struct obj_section *osect;
 356
 357       ALL_OBJFILE_OSECTIONS (faddr_sect->objfile, osect)
 358         {
 359           if (strcmp (osect->the_bfd_section->name, ".dynamic") == 0)
 360             break;
 361         }
 362
 363       if (osect < faddr_sect->objfile->sections_end)
 364         {
 365           CORE_ADDR addr, endaddr;
 366
 367           addr = obj_section_addr (osect);
 368           endaddr = obj_section_endaddr (osect);
 369
 370           while (addr < 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 < 64; 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 += 4;
 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_unwinder (gdbarch, &hppa_linux_sigtramp_frame_unwind);
 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   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
 546
 547   /* Enable TLS support.  */
 548   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 549                                              svr4_fetch_objfile_link_map);
 550 }
 551
 552 void
 553 _initialize_hppa_linux_tdep (void)
 554 {
 555   gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX, hppa_linux_init_abi);
 556   gdbarch_register_osabi (bfd_arch_hppa, bfd_mach_hppa20w, GDB_OSABI_LINUX, hppa_linux_init_abi);
 557 }