gdb/hppa-linux-tdep.c

   1 /* Target-dependent code for GNU/Linux running on PA-RISC, for GDB.
   2
   3    Copyright (C) 2004-2024 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 "extract-store-integer.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 #include "linux-tdep.h"
  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 >= 0 && 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   return -1;
  50 }
  51
  52 static void
  53 hppa_linux_target_write_pc (struct regcache *regcache, CORE_ADDR v)
  54 {
  55   /* Probably this should be done by the kernel, but it isn't.  */
  56   regcache_cooked_write_unsigned (regcache, HPPA_PCOQ_HEAD_REGNUM, v | 0x3);
  57   regcache_cooked_write_unsigned (regcache,
  58                                   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 (struct gdbarch *gdbarch, CORE_ADDR pc,
  91                      struct insn_pattern *pattern,
  92                      unsigned int *insn)
  93 {
  94   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  95   int i;
  96   CORE_ADDR npc = pc;
  97
  98   for (i = 0; pattern[i].mask; i++)
  99     {
 100       gdb_byte buf[4];
 101
 102       target_read_memory (npc, buf, 4);
 103       insn[i] = extract_unsigned_integer (buf, 4, byte_order);
 104       if ((insn[i] & pattern[i].mask) == pattern[i].data)
 105         npc += 4;
 106       else
 107         return 0;
 108     }
 109   return 1;
 110 }
 111
 112 /* Signal frames.  */
 113
 114 /* (This is derived from MD_FALLBACK_FRAME_STATE_FOR in gcc.)
 115
 116    Unfortunately, because of various bugs and changes to the kernel,
 117    we have several cases to deal with.
 118
 119    In 2.4, the signal trampoline is 4 bytes, and pc should point directly at
 120    the beginning of the trampoline and struct rt_sigframe.
 121
 122    In <= 2.6.5-rc2-pa3, the signal trampoline is 9 bytes, and pc points at
 123    the 4th word in the trampoline structure.  This is wrong, it should point
 124    at the 5th word.  This is fixed in 2.6.5-rc2-pa4.
 125
 126    To detect these cases, we first take pc, align it to 64-bytes
 127    to get the beginning of the signal frame, and then check offsets 0, 4
 128    and 5 to see if we found the beginning of the trampoline.  This will
 129    tell us how to locate the sigcontext structure.
 130
 131    Note that with a 2.4 64-bit kernel, the signal context is not properly
 132    passed back to userspace so the unwind will not work correctly.  */
 133 static CORE_ADDR
 134 hppa_linux_sigtramp_find_sigcontext (struct gdbarch *gdbarch, CORE_ADDR pc)
 135 {
 136   unsigned int dummy[HPPA_MAX_INSN_PATTERN_LEN];
 137   int offs = 0;
 138   int attempt;
 139   /* offsets to try to find the trampoline */
 140   static int pcoffs[] = { 0, 4*4, 5*4 };
 141   /* offsets to the rt_sigframe structure */
 142   static int sfoffs[] = { 4*4, 10*4, 10*4 };
 143   CORE_ADDR sp;
 144
 145   /* Most of the time, this will be correct.  The one case when this will
 146      fail is if the user defined an alternate stack, in which case the
 147      beginning of the stack will not be align_down (pc, 64).  */
 148   sp = align_down (pc, 64);
 149
 150   /* rt_sigreturn trampoline:
 151      3419000x ldi 0, %r25 or ldi 1, %r25   (x = 0 or 2)
 152      3414015a ldi __NR_rt_sigreturn, %r20
 153      e4008200 be,l 0x100(%sr2, %r0), %sr0, %r31
 154      08000240 nop  */
 155
 156   for (attempt = 0; attempt < ARRAY_SIZE (pcoffs); attempt++)
 157     {
 158       if (insns_match_pattern (gdbarch, sp + pcoffs[attempt],
 159                                hppa_sigtramp, dummy))
 160         {
 161           offs = sfoffs[attempt];
 162           break;
 163         }
 164     }
 165
 166   if (offs == 0)
 167     {
 168       if (insns_match_pattern (gdbarch, pc, hppa_sigtramp, dummy))
 169         {
 170           /* sigaltstack case: we have no way of knowing which offset to
 171              use in this case; default to new kernel handling.  If this is
 172              wrong the unwinding will fail.  */
 173           attempt = 2;
 174           sp = pc - pcoffs[attempt];
 175         }
 176       else
 177         return 0;
 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[attempt] + 128 + 24;
 187 }
 188
 189 struct hppa_linux_sigtramp_unwind_cache
 190 {
 191   CORE_ADDR base;
 192   trad_frame_saved_reg *saved_regs;
 193 };
 194
 195 static struct hppa_linux_sigtramp_unwind_cache *
 196 hppa_linux_sigtramp_frame_unwind_cache (const frame_info_ptr &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 (struct hppa_linux_sigtramp_unwind_cache *) *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 (gdbarch, 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.  */
 228   info->saved_regs[HPPA_IPSW_REGNUM].set_addr (scptr);
 229   scptr += 4;
 230
 231   /* General registers.  */
 232   for (i = 1; i < 32; i++)
 233     {
 234       info->saved_regs[HPPA_R0_REGNUM + i].set_addr (scptr);
 235       scptr += 4;
 236     }
 237
 238   /* Pad to long long boundary.  */
 239   scptr += 4;
 240
 241   /* FP regs; FP0-3 are not restored.  */
 242   scptr += (8 * 4);
 243
 244   for (i = 4; i < 32; i++)
 245     {
 246       info->saved_regs[HPPA_FP0_REGNUM + (i * 2)].set_addr (scptr);
 247       scptr += 4;
 248       info->saved_regs[HPPA_FP0_REGNUM + (i * 2) + 1].set_addr (scptr);
 249       scptr += 4;
 250     }
 251
 252   /* IASQ/IAOQ.  */
 253   info->saved_regs[HPPA_PCSQ_HEAD_REGNUM].set_addr (scptr);
 254   scptr += 4;
 255   info->saved_regs[HPPA_PCSQ_TAIL_REGNUM].set_addr (scptr);
 256   scptr += 4;
 257
 258   info->saved_regs[HPPA_PCOQ_HEAD_REGNUM].set_addr (scptr);
 259   scptr += 4;
 260   info->saved_regs[HPPA_PCOQ_TAIL_REGNUM].set_addr (scptr);
 261   scptr += 4;
 262
 263   info->saved_regs[HPPA_SAR_REGNUM].set_addr (scptr);
 264
 265   info->base = get_frame_register_unsigned (this_frame, HPPA_SP_REGNUM);
 266
 267   return info;
 268 }
 269
 270 static void
 271 hppa_linux_sigtramp_frame_this_id (const frame_info_ptr &this_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 (this_frame, this_prologue_cache);
 277   *this_id = frame_id_build (info->base, get_frame_pc (this_frame));
 278 }
 279
 280 static struct value *
 281 hppa_linux_sigtramp_frame_prev_register (const frame_info_ptr &this_frame,
 282                                          void **this_prologue_cache,
 283                                          int regnum)
 284 {
 285   struct hppa_linux_sigtramp_unwind_cache *info
 286     = hppa_linux_sigtramp_frame_unwind_cache (this_frame, this_prologue_cache);
 287   return hppa_frame_prev_register_helper (this_frame,
 288                                           info->saved_regs, regnum);
 289 }
 290
 291 /* hppa-linux always uses "new-style" rt-signals.  The signal handler's return
 292    address should point to a signal trampoline on the stack.  The signal
 293    trampoline is embedded in a rt_sigframe structure that is aligned on
 294    the stack.  We take advantage of the fact that sp must be 64-byte aligned,
 295    and the trampoline is small, so by rounding down the trampoline address
 296    we can find the beginning of the struct rt_sigframe.  */
 297 static int
 298 hppa_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
 299                                    const frame_info_ptr &this_frame,
 300                                    void **this_prologue_cache)
 301 {
 302   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 303   CORE_ADDR pc = get_frame_pc (this_frame);
 304
 305   if (hppa_linux_sigtramp_find_sigcontext (gdbarch, pc))
 306     return 1;
 307
 308   return 0;
 309 }
 310
 311 static const struct frame_unwind_legacy hppa_linux_sigtramp_frame_unwind (
 312   "hppa linux sigtramp",
 313   SIGTRAMP_FRAME,
 314   FRAME_UNWIND_ARCH,
 315   default_frame_unwind_stop_reason,
 316   hppa_linux_sigtramp_frame_this_id,
 317   hppa_linux_sigtramp_frame_prev_register,
 318   NULL,
 319   hppa_linux_sigtramp_frame_sniffer
 320 );
 321
 322 /* Attempt to find (and return) the global pointer for the given
 323    function.
 324
 325    This is a rather nasty bit of code searchs for the .dynamic section
 326    in the objfile corresponding to the pc of the function we're trying
 327    to call.  Once it finds the addresses at which the .dynamic section
 328    lives in the child process, it scans the Elf32_Dyn entries for a
 329    DT_PLTGOT tag.  If it finds one of these, the corresponding
 330    d_un.d_ptr value is the global pointer.  */
 331
 332 static CORE_ADDR
 333 hppa_linux_find_global_pointer (struct gdbarch *gdbarch,
 334                                 struct value *function)
 335 {
 336   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 337   struct obj_section *faddr_sect;
 338   CORE_ADDR faddr;
 339
 340   faddr = value_as_address (function);
 341
 342   /* Is this a plabel? If so, dereference it to get the gp value.  */
 343   if (faddr & 2)
 344     {
 345       int status;
 346       gdb_byte buf[4];
 347
 348       faddr &= ~3;
 349
 350       status = target_read_memory (faddr + 4, buf, sizeof (buf));
 351       if (status == 0)
 352         return extract_unsigned_integer (buf, sizeof (buf), byte_order);
 353     }
 354
 355   /* If the address is in the plt section, then the real function hasn't
 356      yet been fixed up by the linker so we cannot determine the gp of
 357      that function.  */
 358   if (in_plt_section (faddr))
 359     return 0;
 360
 361   faddr_sect = find_pc_section (faddr);
 362   if (faddr_sect != NULL)
 363     {
 364       for (obj_section *osect : faddr_sect->objfile->sections ())
 365         {
 366           if (strcmp (osect->the_bfd_section->name, ".dynamic") == 0)
 367             {
 368               CORE_ADDR addr, endaddr;
 369
 370               addr = osect->addr ();
 371               endaddr = osect->endaddr ();
 372
 373               while (addr < endaddr)
 374                 {
 375                   int status;
 376                   LONGEST tag;
 377                   gdb_byte buf[4];
 378
 379                   status = target_read_memory (addr, buf, sizeof (buf));
 380                   if (status != 0)
 381                     break;
 382                   tag = extract_signed_integer (buf, byte_order);
 383
 384                   if (tag == DT_PLTGOT)
 385                     {
 386                       CORE_ADDR global_pointer;
 387
 388                       status = target_read_memory (addr + 4, buf,
 389                                                    sizeof (buf));
 390                       if (status != 0)
 391                         break;
 392                       global_pointer
 393                         = extract_unsigned_integer (buf, sizeof (buf),
 394                                                     byte_order);
 395                       /* The payoff...  */
 396                       return global_pointer;
 397                     }
 398
 399                   if (tag == DT_NULL)
 400                     break;
 401
 402                   addr += 8;
 403                 }
 404               break;
 405             }
 406         }
 407     }
 408   return 0;
 409 }
 410 \f
 411 /*
 412  * Registers saved in a coredump:
 413  * gr0..gr31
 414  * sr0..sr7
 415  * iaoq0..iaoq1
 416  * iasq0..iasq1
 417  * sar, iir, isr, ior, ipsw
 418  * cr0, cr24..cr31
 419  * cr8,9,12,13
 420  * cr10, cr15
 421  */
 422
 423 static const struct regcache_map_entry hppa_linux_gregmap[] =
 424   {
 425     { 32, HPPA_R0_REGNUM },
 426     { 1, HPPA_SR4_REGNUM+1 },
 427     { 1, HPPA_SR4_REGNUM+2 },
 428     { 1, HPPA_SR4_REGNUM+3 },
 429     { 1, HPPA_SR4_REGNUM+4 },
 430     { 1, HPPA_SR4_REGNUM },
 431     { 1, HPPA_SR4_REGNUM+5 },
 432     { 1, HPPA_SR4_REGNUM+6 },
 433     { 1, HPPA_SR4_REGNUM+7 },
 434     { 1, HPPA_PCOQ_HEAD_REGNUM },
 435     { 1, HPPA_PCOQ_TAIL_REGNUM },
 436     { 1, HPPA_PCSQ_HEAD_REGNUM },
 437     { 1, HPPA_PCSQ_TAIL_REGNUM },
 438     { 1, HPPA_SAR_REGNUM },
 439     { 1, HPPA_IIR_REGNUM },
 440     { 1, HPPA_ISR_REGNUM },
 441     { 1, HPPA_IOR_REGNUM },
 442     { 1, HPPA_IPSW_REGNUM },
 443     { 1, HPPA_RCR_REGNUM },
 444     { 8, HPPA_TR0_REGNUM },
 445     { 4, HPPA_PID0_REGNUM },
 446     { 1, HPPA_CCR_REGNUM },
 447     { 1, HPPA_EIEM_REGNUM },
 448     { 0 }
 449   };
 450
 451 static const struct regcache_map_entry hppa_linux_fpregmap[] =
 452   {
 453     /* FIXME: Only works for 32-bit mode.  In 64-bit mode there should
 454        be 32 fpregs, 8 bytes each.  */
 455     { 64, HPPA_FP0_REGNUM, 4 },
 456     { 0 }
 457   };
 458
 459 /* HPPA Linux kernel register set.  */
 460 static const struct regset hppa_linux_regset =
 461 {
 462   hppa_linux_gregmap,
 463   regcache_supply_regset, regcache_collect_regset
 464 };
 465
 466 static const struct regset hppa_linux_fpregset =
 467 {
 468   hppa_linux_fpregmap,
 469   regcache_supply_regset, regcache_collect_regset
 470 };
 471
 472 static void
 473 hppa_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
 474                                          iterate_over_regset_sections_cb *cb,
 475                                          void *cb_data,
 476                                          const struct regcache *regcache)
 477 {
 478   hppa_gdbarch_tdep *tdep = gdbarch_tdep<hppa_gdbarch_tdep> (gdbarch);
 479
 480   cb (".reg", 80 * tdep->bytes_per_address, 80 * tdep->bytes_per_address,
 481       &hppa_linux_regset, NULL, cb_data);
 482   cb (".reg2", 64 * 4, 64 * 4, &hppa_linux_fpregset, NULL, cb_data);
 483 }
 484
 485 static void
 486 hppa_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 487 {
 488   hppa_gdbarch_tdep *tdep = gdbarch_tdep<hppa_gdbarch_tdep> (gdbarch);
 489
 490   linux_init_abi (info, gdbarch, 0);
 491
 492   /* GNU/Linux is always ELF.  */
 493   tdep->is_elf = 1;
 494
 495   tdep->find_global_pointer = hppa_linux_find_global_pointer;
 496
 497   set_gdbarch_write_pc (gdbarch, hppa_linux_target_write_pc);
 498
 499   frame_unwind_append_unwinder (gdbarch, &hppa_linux_sigtramp_frame_unwind);
 500
 501   /* GNU/Linux uses SVR4-style shared libraries.  */
 502   set_solib_svr4_fetch_link_map_offsets
 503     (gdbarch, linux_ilp32_fetch_link_map_offsets);
 504
 505   tdep->in_solib_call_trampoline = hppa_in_solib_call_trampoline;
 506   set_gdbarch_skip_trampoline_code (gdbarch, hppa_skip_trampoline_code);
 507
 508   /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
 509   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 510
 511   /* On hppa-linux, currently, sizeof(long double) == 8.  There has been
 512      some discussions to support 128-bit long double, but it requires some
 513      more work in gcc and glibc first.  */
 514   set_gdbarch_long_double_bit (gdbarch, 64);
 515   set_gdbarch_long_double_format (gdbarch, floatformats_ieee_double);
 516
 517   set_gdbarch_iterate_over_regset_sections
 518     (gdbarch, hppa_linux_iterate_over_regset_sections);
 519
 520   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, hppa_dwarf_reg_to_regnum);
 521
 522   /* Enable TLS support.  */
 523   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 524                                              svr4_fetch_objfile_link_map);
 525 }
 526
 527 void _initialize_hppa_linux_tdep ();
 528 void
 529 _initialize_hppa_linux_tdep ()
 530 {
 531   gdbarch_register_osabi (bfd_arch_hppa, 0, GDB_OSABI_LINUX,
 532                           hppa_linux_init_abi);
 533   gdbarch_register_osabi (bfd_arch_hppa, bfd_mach_hppa20w,
 534                           GDB_OSABI_LINUX, hppa_linux_init_abi);
 535 }