gdb/sparc64-obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/sparc64.
   2
   3    Copyright (C) 2004-2021 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   SIGTRAMP_FRAME,
 226   default_frame_unwind_stop_reason,
 227   sparc64obsd_frame_this_id,
 228   sparc64obsd_frame_prev_register,
 229   NULL,
 230   sparc64obsd_sigtramp_frame_sniffer
 231 };
 232 \f
 233 /* Kernel debugging support.  */
 234
 235 static struct sparc_frame_cache *
 236 sparc64obsd_trapframe_cache (struct frame_info *this_frame, void **this_cache)
 237 {
 238   struct sparc_frame_cache *cache;
 239   CORE_ADDR sp, trapframe_addr;
 240   int regnum;
 241
 242   if (*this_cache)
 243     return (struct sparc_frame_cache *) *this_cache;
 244
 245   cache = sparc_frame_cache (this_frame, this_cache);
 246   gdb_assert (cache == *this_cache);
 247
 248   sp = get_frame_register_unsigned (this_frame, SPARC_SP_REGNUM);
 249   trapframe_addr = sp + BIAS + 176;
 250
 251   cache->saved_regs = trad_frame_alloc_saved_regs (this_frame);
 252
 253   cache->saved_regs[SPARC64_STATE_REGNUM].set_addr (trapframe_addr);
 254   cache->saved_regs[SPARC64_PC_REGNUM].set_addr (trapframe_addr + 8);
 255   cache->saved_regs[SPARC64_NPC_REGNUM].set_addr (trapframe_addr + 16);
 256
 257   for (regnum = SPARC_G0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
 258     cache->saved_regs[regnum].set_addr (trapframe_addr + 48
 259                                         + (regnum - SPARC_G0_REGNUM) * 8);
 260
 261   return cache;
 262 }
 263
 264 static void
 265 sparc64obsd_trapframe_this_id (struct frame_info *this_frame,
 266                                void **this_cache, struct frame_id *this_id)
 267 {
 268   struct sparc_frame_cache *cache =
 269     sparc64obsd_trapframe_cache (this_frame, this_cache);
 270
 271   (*this_id) = frame_id_build (cache->base, cache->pc);
 272 }
 273
 274 static struct value *
 275 sparc64obsd_trapframe_prev_register (struct frame_info *this_frame,
 276                                      void **this_cache, int regnum)
 277 {
 278   struct sparc_frame_cache *cache =
 279     sparc64obsd_trapframe_cache (this_frame, this_cache);
 280
 281   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
 282 }
 283
 284 static int
 285 sparc64obsd_trapframe_sniffer (const struct frame_unwind *self,
 286                                struct frame_info *this_frame,
 287                                void **this_cache)
 288 {
 289   CORE_ADDR pc;
 290   ULONGEST pstate;
 291   const char *name;
 292
 293   /* Check whether we are in privileged mode, and bail out if we're not.  */
 294   pstate = get_frame_register_unsigned (this_frame, SPARC64_PSTATE_REGNUM);
 295   if ((pstate & SPARC64_PSTATE_PRIV) == 0)
 296     return 0;
 297
 298   pc = get_frame_address_in_block (this_frame);
 299   find_pc_partial_function (pc, &name, NULL, NULL);
 300   if (name && strcmp (name, "Lslowtrap_reenter") == 0)
 301     return 1;
 302
 303   return 0;
 304 }
 305
 306 static const struct frame_unwind sparc64obsd_trapframe_unwind =
 307 {
 308   NORMAL_FRAME,
 309   default_frame_unwind_stop_reason,
 310   sparc64obsd_trapframe_this_id,
 311   sparc64obsd_trapframe_prev_register,
 312   NULL,
 313   sparc64obsd_trapframe_sniffer
 314 };
 315 \f
 316
 317 /* Threads support.  */
 318
 319 /* Offset wthin the thread structure where we can find %fp and %i7.  */
 320 #define SPARC64OBSD_UTHREAD_FP_OFFSET   232
 321 #define SPARC64OBSD_UTHREAD_PC_OFFSET   240
 322
 323 static void
 324 sparc64obsd_supply_uthread (struct regcache *regcache,
 325                             int regnum, CORE_ADDR addr)
 326 {
 327   struct gdbarch *gdbarch = regcache->arch ();
 328   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 329   CORE_ADDR fp, fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 330   gdb_byte buf[8];
 331
 332   /* This function calls functions that depend on the global current thread.  */
 333   gdb_assert (regcache->ptid () == inferior_ptid);
 334
 335   gdb_assert (regnum >= -1);
 336
 337   fp = read_memory_unsigned_integer (fp_addr, 8, byte_order);
 338   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 339     {
 340       store_unsigned_integer (buf, 8, byte_order, fp);
 341       regcache->raw_supply (SPARC_SP_REGNUM, buf);
 342
 343       if (regnum == SPARC_SP_REGNUM)
 344         return;
 345     }
 346
 347   if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM
 348       || regnum == -1)
 349     {
 350       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 351
 352       i7 = read_memory_unsigned_integer (i7_addr, 8, byte_order);
 353       if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 354         {
 355           store_unsigned_integer (buf, 8, byte_order, i7 + 8);
 356           regcache->raw_supply (SPARC64_PC_REGNUM, buf);
 357         }
 358       if (regnum == SPARC64_NPC_REGNUM || regnum == -1)
 359         {
 360           store_unsigned_integer (buf, 8, byte_order, i7 + 12);
 361           regcache->raw_supply (SPARC64_NPC_REGNUM, buf);
 362         }
 363
 364       if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM)
 365         return;
 366     }
 367
 368   sparc_supply_rwindow (regcache, fp, regnum);
 369 }
 370
 371 static void
 372 sparc64obsd_collect_uthread(const struct regcache *regcache,
 373                             int regnum, CORE_ADDR addr)
 374 {
 375   struct gdbarch *gdbarch = regcache->arch ();
 376   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 377   CORE_ADDR sp;
 378   gdb_byte buf[8];
 379
 380   /* This function calls functions that depend on the global current thread.  */
 381   gdb_assert (regcache->ptid () == inferior_ptid);
 382
 383   gdb_assert (regnum >= -1);
 384
 385   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 386     {
 387       CORE_ADDR fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 388
 389       regcache->raw_collect (SPARC_SP_REGNUM, buf);
 390       write_memory (fp_addr,buf, 8);
 391     }
 392
 393   if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 394     {
 395       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 396
 397       regcache->raw_collect (SPARC64_PC_REGNUM, buf);
 398       i7 = extract_unsigned_integer (buf, 8, byte_order) - 8;
 399       write_memory_unsigned_integer (i7_addr, 8, byte_order, i7);
 400
 401       if (regnum == SPARC64_PC_REGNUM)
 402         return;
 403     }
 404
 405   regcache->raw_collect (SPARC_SP_REGNUM, buf);
 406   sp = extract_unsigned_integer (buf, 8, byte_order);
 407   sparc_collect_rwindow (regcache, sp, regnum);
 408 }
 409 \f
 410
 411 static const struct regset sparc64obsd_gregset =
 412   {
 413     NULL, sparc64obsd_supply_gregset, NULL
 414   };
 415
 416 static const struct regset sparc64obsd_fpregset =
 417   {
 418     NULL, sparc64obsd_supply_fpregset, NULL
 419   };
 420
 421 static void
 422 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 423 {
 424   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 425
 426   tdep->gregset = &sparc64obsd_gregset;
 427   tdep->sizeof_gregset = 288;
 428   tdep->fpregset = &sparc64obsd_fpregset;
 429   tdep->sizeof_fpregset = 272;
 430
 431   /* Make sure we can single-step "new" syscalls.  */
 432   tdep->step_trap = sparcnbsd_step_trap;
 433
 434   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_frame_unwind);
 435   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_trapframe_unwind);
 436
 437   sparc64_init_abi (info, gdbarch);
 438   obsd_init_abi (info, gdbarch);
 439
 440   /* OpenBSD/sparc64 has SVR4-style shared libraries.  */
 441   set_solib_svr4_fetch_link_map_offsets
 442     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 443   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
 444
 445   /* OpenBSD provides a user-level threads implementation.  */
 446   bsd_uthread_set_supply_uthread (gdbarch, sparc64obsd_supply_uthread);
 447   bsd_uthread_set_collect_uthread (gdbarch, sparc64obsd_collect_uthread);
 448 }
 449
 450 void _initialize_sparc64obsd_tdep ();
 451 void
 452 _initialize_sparc64obsd_tdep ()
 453 {
 454   gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
 455                           GDB_OSABI_OPENBSD, sparc64obsd_init_abi);
 456 }