gdb/sparc64obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/sparc64.
   2
   3    Copyright (C) 2004-2014 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 "gdb_assert.h"
  32
  33 #include "obsd-tdep.h"
  34 #include "sparc64-tdep.h"
  35 #include "solib-svr4.h"
  36 #include "bsd-uthread.h"
  37
  38 /* Older OpenBSD versions used the traditional NetBSD core file
  39    format, even for ports that use ELF.  These core files don't use
  40    multiple register sets.  Instead, the general-purpose and
  41    floating-point registers are lumped together in a single section.
  42    Unlike on NetBSD, OpenBSD uses a different layout for its
  43    general-purpose registers than the layout used for ptrace(2).
  44
  45    Newer OpenBSD versions use ELF core files.  Here the register sets
  46    match the ptrace(2) layout.  */
  47
  48 /* From <machine/reg.h>.  */
  49 const struct sparc_gregset sparc64obsd_gregset =
  50 {
  51   0 * 8,                        /* "tstate" */
  52   1 * 8,                        /* %pc */
  53   2 * 8,                        /* %npc */
  54   3 * 8,                        /* %y */
  55   -1,                           /* %fprs */
  56   -1,
  57   5 * 8,                        /* %g1 */
  58   20 * 8,                       /* %l0 */
  59   4                             /* sizeof (%y) */
  60 };
  61
  62 const struct sparc_gregset sparc64obsd_core_gregset =
  63 {
  64   0 * 8,                        /* "tstate" */
  65   1 * 8,                        /* %pc */
  66   2 * 8,                        /* %npc */
  67   3 * 8,                        /* %y */
  68   -1,                           /* %fprs */
  69   -1,
  70   7 * 8,                        /* %g1 */
  71   22 * 8,                       /* %l0 */
  72   4                             /* sizeof (%y) */
  73 };
  74
  75 static void
  76 sparc64obsd_supply_gregset (const struct regset *regset,
  77                             struct regcache *regcache,
  78                             int regnum, const void *gregs, size_t len)
  79 {
  80   const void *fpregs = (char *)gregs + 288;
  81
  82   if (len < 832)
  83     {
  84       sparc64_supply_gregset (&sparc64obsd_gregset, regcache, regnum, gregs);
  85       return;
  86     }
  87
  88   sparc64_supply_gregset (&sparc64obsd_core_gregset, regcache, regnum, gregs);
  89   sparc64_supply_fpregset (&sparc64_bsd_fpregset, regcache, regnum, fpregs);
  90 }
  91
  92 static void
  93 sparc64obsd_supply_fpregset (const struct regset *regset,
  94                              struct regcache *regcache,
  95                              int regnum, const void *fpregs, size_t len)
  96 {
  97   sparc64_supply_fpregset (&sparc64_bsd_fpregset, regcache, regnum, fpregs);
  98 }
  99 \f
 100
 101 /* Signal trampolines.  */
 102
 103 /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
 104    in virtual memory.  The randomness makes it somewhat tricky to
 105    detect it, but fortunately we can rely on the fact that the start
 106    of the sigtramp routine is page-aligned.  We recognize the
 107    trampoline by looking for the code that invokes the sigreturn
 108    system call.  The offset where we can find that code varies from
 109    release to release.
 110
 111    By the way, the mapping mentioned above is read-only, so you cannot
 112    place a breakpoint in the signal trampoline.  */
 113
 114 /* Default page size.  */
 115 static const int sparc64obsd_page_size = 8192;
 116
 117 /* Offset for sigreturn(2).  */
 118 static const int sparc64obsd_sigreturn_offset[] = {
 119   0xf0,                         /* OpenBSD 3.8 */
 120   0xec,                         /* OpenBSD 3.6 */
 121   0xe8,                         /* OpenBSD 3.2 */
 122   -1
 123 };
 124
 125 static int
 126 sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, const char *name)
 127 {
 128   CORE_ADDR start_pc = (pc & ~(sparc64obsd_page_size - 1));
 129   unsigned long insn;
 130   const int *offset;
 131
 132   if (name)
 133     return 0;
 134
 135   for (offset = sparc64obsd_sigreturn_offset; *offset != -1; offset++)
 136     {
 137       /* Check for "restore %g0, SYS_sigreturn, %g1".  */
 138       insn = sparc_fetch_instruction (start_pc + *offset);
 139       if (insn != 0x83e82067)
 140         continue;
 141
 142       /* Check for "t ST_SYSCALL".  */
 143       insn = sparc_fetch_instruction (start_pc + *offset + 8);
 144       if (insn != 0x91d02000)
 145         continue;
 146
 147       return 1;
 148     }
 149
 150   return 0;
 151 }
 152
 153 static struct sparc_frame_cache *
 154 sparc64obsd_frame_cache (struct frame_info *this_frame, void **this_cache)
 155 {
 156   struct sparc_frame_cache *cache;
 157   CORE_ADDR addr;
 158
 159   if (*this_cache)
 160     return *this_cache;
 161
 162   cache = sparc_frame_cache (this_frame, this_cache);
 163   gdb_assert (cache == *this_cache);
 164
 165   /* If we couldn't find the frame's function, we're probably dealing
 166      with an on-stack signal trampoline.  */
 167   if (cache->pc == 0)
 168     {
 169       cache->pc = get_frame_pc (this_frame);
 170       cache->pc &= ~(sparc64obsd_page_size - 1);
 171
 172       /* Since we couldn't find the frame's function, the cache was
 173          initialized under the assumption that we're frameless.  */
 174       sparc_record_save_insn (cache);
 175       addr = get_frame_register_unsigned (this_frame, SPARC_FP_REGNUM);
 176       if (addr & 1)
 177         addr += BIAS;
 178       cache->base = addr;
 179     }
 180
 181   /* We find the appropriate instance of `struct sigcontext' at a
 182      fixed offset in the signal frame.  */
 183   addr = cache->base + 128 + 16;
 184   cache->saved_regs = sparc64nbsd_sigcontext_saved_regs (addr, this_frame);
 185
 186   return cache;
 187 }
 188
 189 static void
 190 sparc64obsd_frame_this_id (struct frame_info *this_frame, void **this_cache,
 191                            struct frame_id *this_id)
 192 {
 193   struct sparc_frame_cache *cache =
 194     sparc64obsd_frame_cache (this_frame, this_cache);
 195
 196   (*this_id) = frame_id_build (cache->base, cache->pc);
 197 }
 198
 199 static struct value *
 200 sparc64obsd_frame_prev_register (struct frame_info *this_frame,
 201                                  void **this_cache, int regnum)
 202 {
 203   struct sparc_frame_cache *cache =
 204     sparc64obsd_frame_cache (this_frame, this_cache);
 205
 206   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
 207 }
 208
 209 static int
 210 sparc64obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 211                                     struct frame_info *this_frame,
 212                                     void **this_cache)
 213 {
 214   CORE_ADDR pc = get_frame_pc (this_frame);
 215   const char *name;
 216
 217   find_pc_partial_function (pc, &name, NULL, NULL);
 218   if (sparc64obsd_pc_in_sigtramp (pc, name))
 219     return 1;
 220
 221   return 0;
 222 }
 223
 224 static const struct frame_unwind sparc64obsd_frame_unwind =
 225 {
 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 *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].addr = trapframe_addr;
 255   cache->saved_regs[SPARC64_PC_REGNUM].addr = trapframe_addr + 8;
 256   cache->saved_regs[SPARC64_NPC_REGNUM].addr = trapframe_addr + 16;
 257
 258   for (regnum = SPARC_G0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
 259     cache->saved_regs[regnum].addr =
 260       trapframe_addr + 48 + (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   NORMAL_FRAME,
 310   default_frame_unwind_stop_reason,
 311   sparc64obsd_trapframe_this_id,
 312   sparc64obsd_trapframe_prev_register,
 313   NULL,
 314   sparc64obsd_trapframe_sniffer
 315 };
 316 \f
 317
 318 /* Threads support.  */
 319
 320 /* Offset wthin the thread structure where we can find %fp and %i7.  */
 321 #define SPARC64OBSD_UTHREAD_FP_OFFSET   232
 322 #define SPARC64OBSD_UTHREAD_PC_OFFSET   240
 323
 324 static void
 325 sparc64obsd_supply_uthread (struct regcache *regcache,
 326                             int regnum, CORE_ADDR addr)
 327 {
 328   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 329   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 330   CORE_ADDR fp, fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 331   gdb_byte buf[8];
 332
 333   gdb_assert (regnum >= -1);
 334
 335   fp = read_memory_unsigned_integer (fp_addr, 8, byte_order);
 336   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 337     {
 338       store_unsigned_integer (buf, 8, byte_order, fp);
 339       regcache_raw_supply (regcache, SPARC_SP_REGNUM, buf);
 340
 341       if (regnum == SPARC_SP_REGNUM)
 342         return;
 343     }
 344
 345   if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM
 346       || regnum == -1)
 347     {
 348       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 349
 350       i7 = read_memory_unsigned_integer (i7_addr, 8, byte_order);
 351       if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 352         {
 353           store_unsigned_integer (buf, 8, byte_order, i7 + 8);
 354           regcache_raw_supply (regcache, SPARC64_PC_REGNUM, buf);
 355         }
 356       if (regnum == SPARC64_NPC_REGNUM || regnum == -1)
 357         {
 358           store_unsigned_integer (buf, 8, byte_order, i7 + 12);
 359           regcache_raw_supply (regcache, SPARC64_NPC_REGNUM, buf);
 360         }
 361
 362       if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM)
 363         return;
 364     }
 365
 366   sparc_supply_rwindow (regcache, fp, regnum);
 367 }
 368
 369 static void
 370 sparc64obsd_collect_uthread(const struct regcache *regcache,
 371                             int regnum, CORE_ADDR addr)
 372 {
 373   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 374   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 375   CORE_ADDR sp;
 376   gdb_byte buf[8];
 377
 378   gdb_assert (regnum >= -1);
 379
 380   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 381     {
 382       CORE_ADDR fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 383
 384       regcache_raw_collect (regcache, SPARC_SP_REGNUM, buf);
 385       write_memory (fp_addr,buf, 8);
 386     }
 387
 388   if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 389     {
 390       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 391
 392       regcache_raw_collect (regcache, SPARC64_PC_REGNUM, buf);
 393       i7 = extract_unsigned_integer (buf, 8, byte_order) - 8;
 394       write_memory_unsigned_integer (i7_addr, 8, byte_order, i7);
 395
 396       if (regnum == SPARC64_PC_REGNUM)
 397         return;
 398     }
 399
 400   regcache_raw_collect (regcache, SPARC_SP_REGNUM, buf);
 401   sp = extract_unsigned_integer (buf, 8, byte_order);
 402   sparc_collect_rwindow (regcache, sp, regnum);
 403 }
 404 \f
 405
 406 static void
 407 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 408 {
 409   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 410
 411   tdep->gregset = regset_alloc (gdbarch, sparc64obsd_supply_gregset, NULL);
 412   tdep->sizeof_gregset = 288;
 413
 414   tdep->fpregset = regset_alloc (gdbarch, sparc64obsd_supply_fpregset, NULL);
 415   tdep->sizeof_fpregset = 272;
 416
 417   /* Make sure we can single-step "new" syscalls.  */
 418   tdep->step_trap = sparcnbsd_step_trap;
 419
 420   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_frame_unwind);
 421   frame_unwind_append_unwinder (gdbarch, &sparc64obsd_trapframe_unwind);
 422
 423   sparc64_init_abi (info, gdbarch);
 424   obsd_init_abi (info, gdbarch);
 425
 426   /* OpenBSD/sparc64 has SVR4-style shared libraries.  */
 427   set_solib_svr4_fetch_link_map_offsets
 428     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 429   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
 430
 431   /* OpenBSD provides a user-level threads implementation.  */
 432   bsd_uthread_set_supply_uthread (gdbarch, sparc64obsd_supply_uthread);
 433   bsd_uthread_set_collect_uthread (gdbarch, sparc64obsd_collect_uthread);
 434 }
 435 \f
 436
 437 /* Provide a prototype to silence -Wmissing-prototypes.  */
 438 void _initialize_sparc64obsd_tdep (void);
 439
 440 void
 441 _initialize_sparc64obsd_tdep (void)
 442 {
 443   gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
 444                           GDB_OSABI_OPENBSD_ELF, sparc64obsd_init_abi);
 445 }