gdb/sparc64-obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/sparc64.
   2
   3    Copyright (C) 2004-2022 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 #include "inferior.h"
  31
  32 #include "obsd-tdep.h"
  33 #include "sparc64-tdep.h"
  34 #include "solib-svr4.h"
  35 #include "bsd-uthread.h"
  36
  37 /* Older OpenBSD versions used the traditional NetBSD core file
  38    format, even for ports that use ELF.  These core files don't use
  39    multiple register sets.  Instead, the general-purpose and
  40    floating-point registers are lumped together in a single section.
  41    Unlike on NetBSD, OpenBSD uses a different layout for its
  42    general-purpose registers than the layout used for ptrace(2).
  43
  44    Newer OpenBSD versions use ELF core files.  Here the register sets
  45    match the ptrace(2) layout.  */
  46
  47 /* From <machine/reg.h>.  */
  48 const struct sparc_gregmap sparc64obsd_gregmap =
  49 {
  50   0 * 8,                        /* "tstate" */
  51   1 * 8,                        /* %pc */
  52   2 * 8,                        /* %npc */
  53   3 * 8,                        /* %y */
  54   -1,                           /* %fprs */
  55   -1,
  56   5 * 8,                        /* %g1 */
  57   20 * 8,                       /* %l0 */
  58   4                             /* sizeof (%y) */
  59 };
  60
  61 const struct sparc_gregmap sparc64obsd_core_gregmap =
  62 {
  63   0 * 8,                        /* "tstate" */
  64   1 * 8,                        /* %pc */
  65   2 * 8,                        /* %npc */
  66   3 * 8,                        /* %y */
  67   -1,                           /* %fprs */
  68   -1,
  69   7 * 8,                        /* %g1 */
  70   22 * 8,                       /* %l0 */
  71   4                             /* sizeof (%y) */
  72 };
  73
  74 static void
  75 sparc64obsd_supply_gregset (const struct regset *regset,
  76                             struct regcache *regcache,
  77                             int regnum, const void *gregs, size_t len)
  78 {
  79   const void *fpregs = (char *)gregs + 288;
  80
  81   if (len < 832)
  82     {
  83       sparc64_supply_gregset (&sparc64obsd_gregmap, regcache, regnum, gregs);
  84       return;
  85     }
  86
  87   sparc64_supply_gregset (&sparc64obsd_core_gregmap, regcache, regnum, gregs);
  88   sparc64_supply_fpregset (&sparc64_bsd_fpregmap, regcache, regnum, fpregs);
  89 }
  90
  91 static void
  92 sparc64obsd_supply_fpregset (const struct regset *regset,
  93                              struct regcache *regcache,
  94                              int regnum, const void *fpregs, size_t len)
  95 {
  96   sparc64_supply_fpregset (&sparc64_bsd_fpregmap, regcache, regnum, fpregs);
  97 }
  98 \f
  99
 100 /* Signal trampolines.  */
 101
 102 /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
 103    in virtual memory.  The randomness makes it somewhat tricky to
 104    detect it, but fortunately we can rely on the fact that the start
 105    of the sigtramp routine is page-aligned.  We recognize the
 106    trampoline by looking for the code that invokes the sigreturn
 107    system call.  The offset where we can find that code varies from
 108    release to release.
 109
 110    By the way, the mapping mentioned above is read-only, so you cannot
 111    place a breakpoint in the signal trampoline.  */
 112
 113 /* Default page size.  */
 114 static const int sparc64obsd_page_size = 8192;
 115
 116 /* Offset for sigreturn(2).  */
 117 static const int sparc64obsd_sigreturn_offset[] = {
 118   0xf0,                         /* OpenBSD 3.8 */
 119   0xec,                         /* OpenBSD 3.6 */
 120   0xe8,                         /* OpenBSD 3.2 */
 121   -1
 122 };
 123
 124 static int
 125 sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, const char *name)
 126 {
 127   CORE_ADDR start_pc = (pc & ~(sparc64obsd_page_size - 1));
 128   unsigned long insn;
 129   const int *offset;
 130
 131   if (name)
 132     return 0;
 133
 134   for (offset = sparc64obsd_sigreturn_offset; *offset != -1; offset++)
 135     {
 136       /* Check for "restore %g0, SYS_sigreturn, %g1".  */
 137       insn = sparc_fetch_instruction (start_pc + *offset);
 138       if (insn != 0x83e82067)
 139         continue;
 140
 141       /* Check for "t ST_SYSCALL".  */
 142       insn = sparc_fetch_instruction (start_pc + *offset + 8);
 143       if (insn != 0x91d02000)
 144         continue;
 145
 146       return 1;
 147     }
 148
 149   return 0;
 150 }
 151
 152 static struct sparc_frame_cache *
 153 sparc64obsd_frame_cache (struct frame_info *this_frame, void **this_cache)
 154 {
 155   struct sparc_frame_cache *cache;
 156   CORE_ADDR addr;
 157
 158   if (*this_cache)
 159     return (struct sparc_frame_cache *) *this_cache;
 160
 161   cache = sparc_frame_cache (this_frame, this_cache);
 162   gdb_assert (cache == *this_cache);
 163
 164   /* If we couldn't find the frame's function, we're probably dealing
 165      with an on-stack signal trampoline.  */
 166   if (cache->pc == 0)
 167     {
 168       cache->pc = get_frame_pc (this_frame);
 169       cache->pc &= ~(sparc64obsd_page_size - 1);
 170
 171       /* Since we couldn't find the frame's function, the cache was
 172          initialized under the assumption that we're frameless.  */
 173       sparc_record_save_insn (cache);
 174       addr = get_frame_register_unsigned (this_frame, SPARC_FP_REGNUM);
 175       if (addr & 1)
 176         addr += BIAS;
 177       cache->base = addr;
 178     }
 179
 180   /* We find the appropriate instance of `struct sigcontext' at a
 181      fixed offset in the signal frame.  */
 182   addr = cache->base + 128 + 16;
 183   cache->saved_regs = sparc64nbsd_sigcontext_saved_regs (addr, this_frame);
 184
 185   return cache;
 186 }
 187
 188 static void
 189 sparc64obsd_frame_this_id (struct frame_info *this_frame, void **this_cache,
 190                            struct frame_id *this_id)
 191 {
 192   struct sparc_frame_cache *cache =
 193     sparc64obsd_frame_cache (this_frame, this_cache);
 194
 195   (*this_id) = frame_id_build (cache->base, cache->pc);
 196 }
 197
 198 static struct value *
 199 sparc64obsd_frame_prev_register (struct frame_info *this_frame,
 200                                  void **this_cache, int regnum)
 201 {
 202   struct sparc_frame_cache *cache =
 203     sparc64obsd_frame_cache (this_frame, this_cache);
 204
 205   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
 206 }
 207
 208 static int
 209 sparc64obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 210                                     struct frame_info *this_frame,
 211                                     void **this_cache)
 212 {
 213   CORE_ADDR pc = get_frame_pc (this_frame);
 214   const char *name;
 215
 216   find_pc_partial_function (pc, &name, NULL, NULL);
 217   if (sparc64obsd_pc_in_sigtramp (pc, name))
 218     return 1;
 219
 220   return 0;
 221 }
 222
 223 static const struct frame_unwind sparc64obsd_frame_unwind =
 224 {
 225   "sparc64 openbsd sigtramp",
 226   SIGTRAMP_FRAME,
 227   default_frame_unwind_stop_reason,
 228   sparc64obsd_frame_this_id,
 229   sparc64obsd_frame_prev_register,
 230   NULL,
 231   sparc64obsd_sigtramp_frame_sniffer
 232 };
 233 \f
 234 /* Kernel debugging support.  */
 235
 236 static struct sparc_frame_cache *
 237 sparc64obsd_trapframe_cache (struct frame_info *this_frame, void **this_cache)
 238 {
 239   struct sparc_frame_cache *cache;
 240   CORE_ADDR sp, trapframe_addr;
 241   int regnum;
 242
 243   if (*this_cache)
 244     return (struct sparc_frame_cache *) *this_cache;
 245
 246   cache = sparc_frame_cache (this_frame, this_cache);
 247   gdb_assert (cache == *this_cache);
 248
 249   sp = get_frame_register_unsigned (this_frame, SPARC_SP_REGNUM);
 250   trapframe_addr = sp + BIAS + 176;
 251
 252   cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
 253
 254   cache->saved_regs[SPARC64_STATE_REGNUM].set_addr (trapframe_addr);
 255   cache->saved_regs[SPARC64_PC_REGNUM].set_addr (trapframe_addr + 8);
 256   cache->saved_regs[SPARC64_NPC_REGNUM].set_addr (trapframe_addr + 16);
 257
 258   for (regnum = SPARC_G0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
 259     cache->saved_regs[regnum].set_addr (trapframe_addr + 48
 260                                         + (regnum - SPARC_G0_REGNUM) * 8);
 261
 262   return cache;
 263 }
 264
 265 static void
 266 sparc64obsd_trapframe_this_id (struct frame_info *this_frame,
 267                                void **this_cache, struct frame_id *this_id)
 268 {
 269   struct sparc_frame_cache *cache =
 270     sparc64obsd_trapframe_cache (this_frame, this_cache);
 271
 272   (*this_id) = frame_id_build (cache->base, cache->pc);
 273 }
 274
 275 static struct value *
 276 sparc64obsd_trapframe_prev_register (struct frame_info *this_frame,
 277                                      void **this_cache, int regnum)
 278 {
 279   struct sparc_frame_cache *cache =
 280     sparc64obsd_trapframe_cache (this_frame, this_cache);
 281
 282   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
 283 }
 284
 285 static int
 286 sparc64obsd_trapframe_sniffer (const struct frame_unwind *self,
 287                                struct frame_info *this_frame,
 288                                void **this_cache)
 289 {
 290   CORE_ADDR pc;
 291   ULONGEST pstate;
 292   const char *name;
 293
 294   /* Check whether we are in privileged mode, and bail out if we're not.  */
 295   pstate = get_frame_register_unsigned (this_frame, SPARC64_PSTATE_REGNUM);
 296   if ((pstate & SPARC64_PSTATE_PRIV) == 0)
 297     return 0;
 298
 299   pc = get_frame_address_in_block (this_frame);
 300   find_pc_partial_function (pc, &name, NULL, NULL);
 301   if (name && strcmp (name, "Lslowtrap_reenter") == 0)
 302     return 1;
 303
 304   return 0;
 305 }
 306
 307 static const struct frame_unwind sparc64obsd_trapframe_unwind =
 308 {
 309   "sparc64 openbsd trap",
 310   NORMAL_FRAME,
 311   default_frame_unwind_stop_reason,
 312   sparc64obsd_trapframe_this_id,
 313   sparc64obsd_trapframe_prev_register,
 314   NULL,
 315   sparc64obsd_trapframe_sniffer
 316 };
 317 \f
 318
 319 /* Threads support.  */
 320
 321 /* Offset wthin the thread structure where we can find %fp and %i7.  */
 322 #define SPARC64OBSD_UTHREAD_FP_OFFSET   232
 323 #define SPARC64OBSD_UTHREAD_PC_OFFSET   240
 324
 325 static void
 326 sparc64obsd_supply_uthread (struct regcache *regcache,
 327                             int regnum, CORE_ADDR addr)
 328 {
 329   struct gdbarch *gdbarch = regcache->arch ();
 330   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 331   CORE_ADDR fp, fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 332   gdb_byte buf[8];
 333
 334   /* This function calls functions that depend on the global current thread.  */
 335   gdb_assert (regcache->ptid () == inferior_ptid);
 336
 337   gdb_assert (regnum >= -1);
 338
 339   fp = read_memory_unsigned_integer (fp_addr, 8, byte_order);
 340   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 341     {
 342       store_unsigned_integer (buf, 8, byte_order, fp);
 343       regcache->raw_supply (SPARC_SP_REGNUM, buf);
 344
 345       if (regnum == SPARC_SP_REGNUM)
 346         return;
 347     }
 348
 349   if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM
 350       || regnum == -1)
 351     {
 352       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 353
 354       i7 = read_memory_unsigned_integer (i7_addr, 8, byte_order);
 355       if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 356         {
 357           store_unsigned_integer (buf, 8, byte_order, i7 + 8);
 358           regcache->raw_supply (SPARC64_PC_REGNUM, buf);
 359         }
 360       if (regnum == SPARC64_NPC_REGNUM || regnum == -1)
 361         {
 362           store_unsigned_integer (buf, 8, byte_order, i7 + 12);
 363           regcache->raw_supply (SPARC64_NPC_REGNUM, buf);
 364         }
 365
 366       if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM)
 367         return;
 368     }
 369
 370   sparc_supply_rwindow (regcache, fp, regnum);
 371 }
 372
 373 static void
 374 sparc64obsd_collect_uthread(const struct regcache *regcache,
 375                             int regnum, CORE_ADDR addr)
 376 {
 377   struct gdbarch *gdbarch = regcache->arch ();
 378   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 379   CORE_ADDR sp;
 380   gdb_byte buf[8];
 381
 382   /* This function calls functions that depend on the global current thread.  */
 383   gdb_assert (regcache->ptid () == inferior_ptid);
 384
 385   gdb_assert (regnum >= -1);
 386
 387   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 388     {
 389       CORE_ADDR fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 390
 391       regcache->raw_collect (SPARC_SP_REGNUM, buf);
 392       write_memory (fp_addr,buf, 8);
 393     }
 394
 395   if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 396     {
 397       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 398
 399       regcache->raw_collect (SPARC64_PC_REGNUM, buf);
 400       i7 = extract_unsigned_integer (buf, 8, byte_order) - 8;
 401       write_memory_unsigned_integer (i7_addr, 8, byte_order, i7);
 402
 403       if (regnum == SPARC64_PC_REGNUM)
 404         return;
 405     }
 406
 407   regcache->raw_collect (SPARC_SP_REGNUM, buf);
 408   sp = extract_unsigned_integer (buf, 8, byte_order);
 409   sparc_collect_rwindow (regcache, sp, regnum);
 410 }
 411 \f
 412
 413 static const struct regset sparc64obsd_gregset =
 414   {
 415     NULL, sparc64obsd_supply_gregset, NULL
 416   };
 417
 418 static const struct regset sparc64obsd_fpregset =
 419   {
 420     NULL, sparc64obsd_supply_fpregset, NULL
 421   };
 422
 423 static void
 424 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 425 {
 426   sparc_gdbarch_tdep *tdep = gdbarch_tdep<sparc_gdbarch_tdep> (gdbarch);
 427
 428   tdep->gregset = &sparc64obsd_gregset;
 429   tdep->sizeof_gregset = 288;
 430   tdep->fpregset = &sparc64obsd_fpregset;
 431   tdep->sizeof_fpregset = 272;
 432
 433   /* Make sure we can single-step "new" syscalls.  */
 434   tdep->step_trap = sparcnbsd_step_trap;
 435
 436   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_frame_unwind);
 437   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_trapframe_unwind);
 438
 439   sparc64_init_abi (info, gdbarch);
 440   obsd_init_abi (info, gdbarch);
 441
 442   /* OpenBSD/sparc64 has SVR4-style shared libraries.  */
 443   set_solib_svr4_fetch_link_map_offsets
 444     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 445   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
 446
 447   /* OpenBSD provides a user-level threads implementation.  */
 448   bsd_uthread_set_supply_uthread (gdbarch, sparc64obsd_supply_uthread);
 449   bsd_uthread_set_collect_uthread (gdbarch, sparc64obsd_collect_uthread);
 450 }
 451
 452 void _initialize_sparc64obsd_tdep ();
 453 void
 454 _initialize_sparc64obsd_tdep ()
 455 {
 456   gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
 457                           GDB_OSABI_OPENBSD, sparc64obsd_init_abi);
 458 }