gdb/sparc64-obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/sparc64.
   2
   3    Copyright (C) 2004-2020 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 "frame.h"
  22 #include "frame-unwind.h"
  23 #include "gdbcore.h"
  24 #include "osabi.h"
  25 #include "regcache.h"
  26 #include "regset.h"
  27 #include "symtab.h"
  28 #include "objfiles.h"
  29 #include "trad-frame.h"
  30
  31 #include "obsd-tdep.h"
  32 #include "sparc64-tdep.h"
  33 #include "solib-svr4.h"
  34 #include "bsd-uthread.h"
  35
  36 /* Older OpenBSD versions used the traditional NetBSD core file
  37    format, even for ports that use ELF.  These core files don't use
  38    multiple register sets.  Instead, the general-purpose and
  39    floating-point registers are lumped together in a single section.
  40    Unlike on NetBSD, OpenBSD uses a different layout for its
  41    general-purpose registers than the layout used for ptrace(2).
  42
  43    Newer OpenBSD versions use ELF core files.  Here the register sets
  44    match the ptrace(2) layout.  */
  45
  46 /* From <machine/reg.h>.  */
  47 const struct sparc_gregmap sparc64obsd_gregmap =
  48 {
  49   0 * 8,                        /* "tstate" */
  50   1 * 8,                        /* %pc */
  51   2 * 8,                        /* %npc */
  52   3 * 8,                        /* %y */
  53   -1,                           /* %fprs */
  54   -1,
  55   5 * 8,                        /* %g1 */
  56   20 * 8,                       /* %l0 */
  57   4                             /* sizeof (%y) */
  58 };
  59
  60 const struct sparc_gregmap sparc64obsd_core_gregmap =
  61 {
  62   0 * 8,                        /* "tstate" */
  63   1 * 8,                        /* %pc */
  64   2 * 8,                        /* %npc */
  65   3 * 8,                        /* %y */
  66   -1,                           /* %fprs */
  67   -1,
  68   7 * 8,                        /* %g1 */
  69   22 * 8,                       /* %l0 */
  70   4                             /* sizeof (%y) */
  71 };
  72
  73 static void
  74 sparc64obsd_supply_gregset (const struct regset *regset,
  75                             struct regcache *regcache,
  76                             int regnum, const void *gregs, size_t len)
  77 {
  78   const void *fpregs = (char *)gregs + 288;
  79
  80   if (len < 832)
  81     {
  82       sparc64_supply_gregset (&sparc64obsd_gregmap, regcache, regnum, gregs);
  83       return;
  84     }
  85
  86   sparc64_supply_gregset (&sparc64obsd_core_gregmap, regcache, regnum, gregs);
  87   sparc64_supply_fpregset (&sparc64_bsd_fpregmap, regcache, regnum, fpregs);
  88 }
  89
  90 static void
  91 sparc64obsd_supply_fpregset (const struct regset *regset,
  92                              struct regcache *regcache,
  93                              int regnum, const void *fpregs, size_t len)
  94 {
  95   sparc64_supply_fpregset (&sparc64_bsd_fpregmap, regcache, regnum, fpregs);
  96 }
  97 \f
  98
  99 /* Signal trampolines.  */
 100
 101 /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
 102    in virtual memory.  The randomness makes it somewhat tricky to
 103    detect it, but fortunately we can rely on the fact that the start
 104    of the sigtramp routine is page-aligned.  We recognize the
 105    trampoline by looking for the code that invokes the sigreturn
 106    system call.  The offset where we can find that code varies from
 107    release to release.
 108
 109    By the way, the mapping mentioned above is read-only, so you cannot
 110    place a breakpoint in the signal trampoline.  */
 111
 112 /* Default page size.  */
 113 static const int sparc64obsd_page_size = 8192;
 114
 115 /* Offset for sigreturn(2).  */
 116 static const int sparc64obsd_sigreturn_offset[] = {
 117   0xf0,                         /* OpenBSD 3.8 */
 118   0xec,                         /* OpenBSD 3.6 */
 119   0xe8,                         /* OpenBSD 3.2 */
 120   -1
 121 };
 122
 123 static int
 124 sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, const char *name)
 125 {
 126   CORE_ADDR start_pc = (pc & ~(sparc64obsd_page_size - 1));
 127   unsigned long insn;
 128   const int *offset;
 129
 130   if (name)
 131     return 0;
 132
 133   for (offset = sparc64obsd_sigreturn_offset; *offset != -1; offset++)
 134     {
 135       /* Check for "restore %g0, SYS_sigreturn, %g1".  */
 136       insn = sparc_fetch_instruction (start_pc + *offset);
 137       if (insn != 0x83e82067)
 138         continue;
 139
 140       /* Check for "t ST_SYSCALL".  */
 141       insn = sparc_fetch_instruction (start_pc + *offset + 8);
 142       if (insn != 0x91d02000)
 143         continue;
 144
 145       return 1;
 146     }
 147
 148   return 0;
 149 }
 150
 151 static struct sparc_frame_cache *
 152 sparc64obsd_frame_cache (struct frame_info *this_frame, void **this_cache)
 153 {
 154   struct sparc_frame_cache *cache;
 155   CORE_ADDR addr;
 156
 157   if (*this_cache)
 158     return (struct sparc_frame_cache *) *this_cache;
 159
 160   cache = sparc_frame_cache (this_frame, this_cache);
 161   gdb_assert (cache == *this_cache);
 162
 163   /* If we couldn't find the frame's function, we're probably dealing
 164      with an on-stack signal trampoline.  */
 165   if (cache->pc == 0)
 166     {
 167       cache->pc = get_frame_pc (this_frame);
 168       cache->pc &= ~(sparc64obsd_page_size - 1);
 169
 170       /* Since we couldn't find the frame's function, the cache was
 171          initialized under the assumption that we're frameless.  */
 172       sparc_record_save_insn (cache);
 173       addr = get_frame_register_unsigned (this_frame, SPARC_FP_REGNUM);
 174       if (addr & 1)
 175         addr += BIAS;
 176       cache->base = addr;
 177     }
 178
 179   /* We find the appropriate instance of `struct sigcontext' at a
 180      fixed offset in the signal frame.  */
 181   addr = cache->base + 128 + 16;
 182   cache->saved_regs = sparc64nbsd_sigcontext_saved_regs (addr, this_frame);
 183
 184   return cache;
 185 }
 186
 187 static void
 188 sparc64obsd_frame_this_id (struct frame_info *this_frame, void **this_cache,
 189                            struct frame_id *this_id)
 190 {
 191   struct sparc_frame_cache *cache =
 192     sparc64obsd_frame_cache (this_frame, this_cache);
 193
 194   (*this_id) = frame_id_build (cache->base, cache->pc);
 195 }
 196
 197 static struct value *
 198 sparc64obsd_frame_prev_register (struct frame_info *this_frame,
 199                                  void **this_cache, int regnum)
 200 {
 201   struct sparc_frame_cache *cache =
 202     sparc64obsd_frame_cache (this_frame, this_cache);
 203
 204   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
 205 }
 206
 207 static int
 208 sparc64obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 209                                     struct frame_info *this_frame,
 210                                     void **this_cache)
 211 {
 212   CORE_ADDR pc = get_frame_pc (this_frame);
 213   const char *name;
 214
 215   find_pc_partial_function (pc, &name, NULL, NULL);
 216   if (sparc64obsd_pc_in_sigtramp (pc, name))
 217     return 1;
 218
 219   return 0;
 220 }
 221
 222 static const struct frame_unwind sparc64obsd_frame_unwind =
 223 {
 224   SIGTRAMP_FRAME,
 225   default_frame_unwind_stop_reason,
 226   sparc64obsd_frame_this_id,
 227   sparc64obsd_frame_prev_register,
 228   NULL,
 229   sparc64obsd_sigtramp_frame_sniffer
 230 };
 231 \f
 232 /* Kernel debugging support.  */
 233
 234 static struct sparc_frame_cache *
 235 sparc64obsd_trapframe_cache (struct frame_info *this_frame, void **this_cache)
 236 {
 237   struct sparc_frame_cache *cache;
 238   CORE_ADDR sp, trapframe_addr;
 239   int regnum;
 240
 241   if (*this_cache)
 242     return (struct sparc_frame_cache *) *this_cache;
 243
 244   cache = sparc_frame_cache (this_frame, this_cache);
 245   gdb_assert (cache == *this_cache);
 246
 247   sp = get_frame_register_unsigned (this_frame, SPARC_SP_REGNUM);
 248   trapframe_addr = sp + BIAS + 176;
 249
 250   cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
 251
 252   cache->saved_regs[SPARC64_STATE_REGNUM].addr = trapframe_addr;
 253   cache->saved_regs[SPARC64_PC_REGNUM].addr = trapframe_addr + 8;
 254   cache->saved_regs[SPARC64_NPC_REGNUM].addr = trapframe_addr + 16;
 255
 256   for (regnum = SPARC_G0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
 257     cache->saved_regs[regnum].addr =
 258       trapframe_addr + 48 + (regnum - SPARC_G0_REGNUM) * 8;
 259
 260   return cache;
 261 }
 262
 263 static void
 264 sparc64obsd_trapframe_this_id (struct frame_info *this_frame,
 265                                void **this_cache, struct frame_id *this_id)
 266 {
 267   struct sparc_frame_cache *cache =
 268     sparc64obsd_trapframe_cache (this_frame, this_cache);
 269
 270   (*this_id) = frame_id_build (cache->base, cache->pc);
 271 }
 272
 273 static struct value *
 274 sparc64obsd_trapframe_prev_register (struct frame_info *this_frame,
 275                                      void **this_cache, int regnum)
 276 {
 277   struct sparc_frame_cache *cache =
 278     sparc64obsd_trapframe_cache (this_frame, this_cache);
 279
 280   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
 281 }
 282
 283 static int
 284 sparc64obsd_trapframe_sniffer (const struct frame_unwind *self,
 285                                struct frame_info *this_frame,
 286                                void **this_cache)
 287 {
 288   CORE_ADDR pc;
 289   ULONGEST pstate;
 290   const char *name;
 291
 292   /* Check whether we are in privileged mode, and bail out if we're not.  */
 293   pstate = get_frame_register_unsigned (this_frame, SPARC64_PSTATE_REGNUM);
 294   if ((pstate & SPARC64_PSTATE_PRIV) == 0)
 295     return 0;
 296
 297   pc = get_frame_address_in_block (this_frame);
 298   find_pc_partial_function (pc, &name, NULL, NULL);
 299   if (name && strcmp (name, "Lslowtrap_reenter") == 0)
 300     return 1;
 301
 302   return 0;
 303 }
 304
 305 static const struct frame_unwind sparc64obsd_trapframe_unwind =
 306 {
 307   NORMAL_FRAME,
 308   default_frame_unwind_stop_reason,
 309   sparc64obsd_trapframe_this_id,
 310   sparc64obsd_trapframe_prev_register,
 311   NULL,
 312   sparc64obsd_trapframe_sniffer
 313 };
 314 \f
 315
 316 /* Threads support.  */
 317
 318 /* Offset wthin the thread structure where we can find %fp and %i7.  */
 319 #define SPARC64OBSD_UTHREAD_FP_OFFSET   232
 320 #define SPARC64OBSD_UTHREAD_PC_OFFSET   240
 321
 322 static void
 323 sparc64obsd_supply_uthread (struct regcache *regcache,
 324                             int regnum, CORE_ADDR addr)
 325 {
 326   struct gdbarch *gdbarch = regcache->arch ();
 327   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 328   CORE_ADDR fp, fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 329   gdb_byte buf[8];
 330
 331   gdb_assert (regnum >= -1);
 332
 333   fp = read_memory_unsigned_integer (fp_addr, 8, byte_order);
 334   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 335     {
 336       store_unsigned_integer (buf, 8, byte_order, fp);
 337       regcache->raw_supply (SPARC_SP_REGNUM, buf);
 338
 339       if (regnum == SPARC_SP_REGNUM)
 340         return;
 341     }
 342
 343   if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM
 344       || regnum == -1)
 345     {
 346       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 347
 348       i7 = read_memory_unsigned_integer (i7_addr, 8, byte_order);
 349       if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 350         {
 351           store_unsigned_integer (buf, 8, byte_order, i7 + 8);
 352           regcache->raw_supply (SPARC64_PC_REGNUM, buf);
 353         }
 354       if (regnum == SPARC64_NPC_REGNUM || regnum == -1)
 355         {
 356           store_unsigned_integer (buf, 8, byte_order, i7 + 12);
 357           regcache->raw_supply (SPARC64_NPC_REGNUM, buf);
 358         }
 359
 360       if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM)
 361         return;
 362     }
 363
 364   sparc_supply_rwindow (regcache, fp, regnum);
 365 }
 366
 367 static void
 368 sparc64obsd_collect_uthread(const struct regcache *regcache,
 369                             int regnum, CORE_ADDR addr)
 370 {
 371   struct gdbarch *gdbarch = regcache->arch ();
 372   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 373   CORE_ADDR sp;
 374   gdb_byte buf[8];
 375
 376   gdb_assert (regnum >= -1);
 377
 378   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 379     {
 380       CORE_ADDR fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 381
 382       regcache->raw_collect (SPARC_SP_REGNUM, buf);
 383       write_memory (fp_addr,buf, 8);
 384     }
 385
 386   if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 387     {
 388       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 389
 390       regcache->raw_collect (SPARC64_PC_REGNUM, buf);
 391       i7 = extract_unsigned_integer (buf, 8, byte_order) - 8;
 392       write_memory_unsigned_integer (i7_addr, 8, byte_order, i7);
 393
 394       if (regnum == SPARC64_PC_REGNUM)
 395         return;
 396     }
 397
 398   regcache->raw_collect (SPARC_SP_REGNUM, buf);
 399   sp = extract_unsigned_integer (buf, 8, byte_order);
 400   sparc_collect_rwindow (regcache, sp, regnum);
 401 }
 402 \f
 403
 404 static const struct regset sparc64obsd_gregset =
 405   {
 406     NULL, sparc64obsd_supply_gregset, NULL
 407   };
 408
 409 static const struct regset sparc64obsd_fpregset =
 410   {
 411     NULL, sparc64obsd_supply_fpregset, NULL
 412   };
 413
 414 static void
 415 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 416 {
 417   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 418
 419   tdep->gregset = &sparc64obsd_gregset;
 420   tdep->sizeof_gregset = 288;
 421   tdep->fpregset = &sparc64obsd_fpregset;
 422   tdep->sizeof_fpregset = 272;
 423
 424   /* Make sure we can single-step "new" syscalls.  */
 425   tdep->step_trap = sparcnbsd_step_trap;
 426
 427   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_frame_unwind);
 428   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_trapframe_unwind);
 429
 430   sparc64_init_abi (info, gdbarch);
 431   obsd_init_abi (info, gdbarch);
 432
 433   /* OpenBSD/sparc64 has SVR4-style shared libraries.  */
 434   set_solib_svr4_fetch_link_map_offsets
 435     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 436   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
 437
 438   /* OpenBSD provides a user-level threads implementation.  */
 439   bsd_uthread_set_supply_uthread (gdbarch, sparc64obsd_supply_uthread);
 440   bsd_uthread_set_collect_uthread (gdbarch, sparc64obsd_collect_uthread);
 441 }
 442
 443 void _initialize_sparc64obsd_tdep ();
 444 void
 445 _initialize_sparc64obsd_tdep ()
 446 {
 447   gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
 448                           GDB_OSABI_OPENBSD, sparc64obsd_init_abi);
 449 }