gdb/sparc64obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/sparc64.
   2
   3    Copyright (C) 2004, 2005, 2006, 2007 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 2 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, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "defs.h"
  23 #include "frame.h"
  24 #include "frame-unwind.h"
  25 #include "gdbcore.h"
  26 #include "osabi.h"
  27 #include "regcache.h"
  28 #include "regset.h"
  29 #include "symtab.h"
  30 #include "objfiles.h"
  31 #include "trad-frame.h"
  32
  33 #include "gdb_assert.h"
  34
  35 #include "obsd-tdep.h"
  36 #include "sparc64-tdep.h"
  37 #include "solib-svr4.h"
  38 #include "bsd-uthread.h"
  39
  40 /* OpenBSD uses the traditional NetBSD core file format, even for
  41    ports that use ELF.  The core files don't use multiple register
  42    sets.  Instead, the general-purpose and floating-point registers
  43    are lumped together in a single section.  Unlike on NetBSD, OpenBSD
  44    uses a different layout for its general-purpose registers than the
  45    layout used for ptrace(2).  */
  46
  47 /* From <machine/reg.h>.  */
  48 const struct sparc_gregset sparc64obsd_core_gregset =
  49 {
  50   0 * 8,                        /* "tstate" */
  51   1 * 8,                        /* %pc */
  52   2 * 8,                        /* %npc */
  53   3 * 8,                        /* %y */
  54   -1,                           /* %fprs */
  55   -1,
  56   7 * 8,                        /* %g1 */
  57   22 * 8,                       /* %l0 */
  58   4                             /* sizeof (%y) */
  59 };
  60
  61 static void
  62 sparc64obsd_supply_gregset (const struct regset *regset,
  63                             struct regcache *regcache,
  64                             int regnum, const void *gregs, size_t len)
  65 {
  66   const char *regs = gregs;
  67
  68   sparc64_supply_gregset (&sparc64obsd_core_gregset, regcache, regnum, regs);
  69   sparc64_supply_fpregset (regcache, regnum, regs + 288);
  70 }
  71 \f
  72
  73 /* Signal trampolines.  */
  74
  75 /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
  76    in virtual memory.  The randomness makes it somewhat tricky to
  77    detect it, but fortunately we can rely on the fact that the start
  78    of the sigtramp routine is page-aligned.  We recognize the
  79    trampoline by looking for the code that invokes the sigreturn
  80    system call.  The offset where we can find that code varies from
  81    release to release.
  82
  83    By the way, the mapping mentioned above is read-only, so you cannot
  84    place a breakpoint in the signal trampoline.  */
  85
  86 /* Default page size.  */
  87 static const int sparc64obsd_page_size = 8192;
  88
  89 /* Offset for sigreturn(2).  */
  90 static const int sparc64obsd_sigreturn_offset[] = {
  91   0xf0,                         /* OpenBSD 3.8 */
  92   0xec,                         /* OpenBSD 3.6 */
  93   0xe8,                         /* OpenBSD 3.2 */
  94   -1
  95 };
  96
  97 static int
  98 sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, char *name)
  99 {
 100   CORE_ADDR start_pc = (pc & ~(sparc64obsd_page_size - 1));
 101   unsigned long insn;
 102   const int *offset;
 103
 104   if (name)
 105     return 0;
 106
 107   for (offset = sparc64obsd_sigreturn_offset; *offset != -1; offset++)
 108     {
 109       /* Check for "restore %g0, SYS_sigreturn, %g1".  */
 110       insn = sparc_fetch_instruction (start_pc + *offset);
 111       if (insn != 0x83e82067)
 112         continue;
 113
 114       /* Check for "t ST_SYSCALL".  */
 115       insn = sparc_fetch_instruction (start_pc + *offset + 8);
 116       if (insn != 0x91d02000)
 117         continue;
 118
 119       return 1;
 120     }
 121
 122   return 0;
 123 }
 124
 125 static struct sparc_frame_cache *
 126 sparc64obsd_frame_cache (struct frame_info *next_frame, void **this_cache)
 127 {
 128   struct sparc_frame_cache *cache;
 129   CORE_ADDR addr;
 130
 131   if (*this_cache)
 132     return *this_cache;
 133
 134   cache = sparc_frame_cache (next_frame, this_cache);
 135   gdb_assert (cache == *this_cache);
 136
 137   /* If we couldn't find the frame's function, we're probably dealing
 138      with an on-stack signal trampoline.  */
 139   if (cache->pc == 0)
 140     {
 141       cache->pc = frame_pc_unwind (next_frame);
 142       cache->pc &= ~(sparc64obsd_page_size - 1);
 143
 144       /* Since we couldn't find the frame's function, the cache was
 145          initialized under the assumption that we're frameless.  */
 146       cache->frameless_p = 0;
 147       addr = frame_unwind_register_unsigned (next_frame, SPARC_FP_REGNUM);
 148       if (addr & 1)
 149         addr += BIAS;
 150       cache->base = addr;
 151     }
 152
 153   /* We find the appropriate instance of `struct sigcontext' at a
 154      fixed offset in the signal frame.  */
 155   addr = cache->base + 128 + 16;
 156   cache->saved_regs = sparc64nbsd_sigcontext_saved_regs (addr, next_frame);
 157
 158   return cache;
 159 }
 160
 161 static void
 162 sparc64obsd_frame_this_id (struct frame_info *next_frame, void **this_cache,
 163                            struct frame_id *this_id)
 164 {
 165   struct sparc_frame_cache *cache =
 166     sparc64obsd_frame_cache (next_frame, this_cache);
 167
 168   (*this_id) = frame_id_build (cache->base, cache->pc);
 169 }
 170
 171 static void
 172 sparc64obsd_frame_prev_register (struct frame_info *next_frame,
 173                                  void **this_cache,
 174                                  int regnum, int *optimizedp,
 175                                  enum lval_type *lvalp, CORE_ADDR *addrp,
 176                                  int *realnump, gdb_byte *valuep)
 177 {
 178   struct sparc_frame_cache *cache =
 179     sparc64obsd_frame_cache (next_frame, this_cache);
 180
 181   trad_frame_get_prev_register (next_frame, cache->saved_regs, regnum,
 182                                 optimizedp, lvalp, addrp, realnump, valuep);
 183 }
 184
 185 static const struct frame_unwind sparc64obsd_frame_unwind =
 186 {
 187   SIGTRAMP_FRAME,
 188   sparc64obsd_frame_this_id,
 189   sparc64obsd_frame_prev_register
 190 };
 191
 192 static const struct frame_unwind *
 193 sparc64obsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
 194 {
 195   CORE_ADDR pc = frame_pc_unwind (next_frame);
 196   char *name;
 197
 198   find_pc_partial_function (pc, &name, NULL, NULL);
 199   if (sparc64obsd_pc_in_sigtramp (pc, name))
 200     return &sparc64obsd_frame_unwind;
 201
 202   return NULL;
 203 }
 204 \f
 205 /* Kernel debugging support.  */
 206
 207 static struct sparc_frame_cache *
 208 sparc64obsd_trapframe_cache(struct frame_info *next_frame, void **this_cache)
 209 {
 210   struct sparc_frame_cache *cache;
 211   CORE_ADDR sp, trapframe_addr;
 212   int regnum;
 213
 214   if (*this_cache)
 215     return *this_cache;
 216
 217   cache = sparc_frame_cache (next_frame, this_cache);
 218   gdb_assert (cache == *this_cache);
 219
 220   sp = frame_unwind_register_unsigned (next_frame, SPARC_SP_REGNUM);
 221   trapframe_addr = sp + BIAS + 176;
 222
 223   cache->saved_regs = trad_frame_alloc_saved_regs (next_frame);
 224
 225   cache->saved_regs[SPARC64_STATE_REGNUM].addr = trapframe_addr;
 226   cache->saved_regs[SPARC64_PC_REGNUM].addr = trapframe_addr + 8;
 227   cache->saved_regs[SPARC64_NPC_REGNUM].addr = trapframe_addr + 16;
 228
 229   for (regnum = SPARC_G0_REGNUM; regnum <= SPARC_I7_REGNUM; regnum++)
 230     cache->saved_regs[regnum].addr =
 231       trapframe_addr + 48 + (regnum - SPARC_G0_REGNUM) * 8;
 232
 233   return cache;
 234 }
 235
 236 static void
 237 sparc64obsd_trapframe_this_id (struct frame_info *next_frame,
 238                                void **this_cache, struct frame_id *this_id)
 239 {
 240   struct sparc_frame_cache *cache =
 241     sparc64obsd_trapframe_cache (next_frame, this_cache);
 242
 243   (*this_id) = frame_id_build (cache->base, cache->pc);
 244 }
 245
 246 static void
 247 sparc64obsd_trapframe_prev_register (struct frame_info *next_frame,
 248                                      void **this_cache,
 249                                      int regnum, int *optimizedp,
 250                                      enum lval_type *lvalp, CORE_ADDR *addrp,
 251                                      int *realnump, gdb_byte *valuep)
 252 {
 253   struct sparc_frame_cache *cache =
 254     sparc64obsd_trapframe_cache (next_frame, this_cache);
 255
 256   trad_frame_get_prev_register (next_frame, cache->saved_regs, regnum,
 257                                 optimizedp, lvalp, addrp, realnump, valuep);
 258 }
 259
 260 static const struct frame_unwind sparc64obsd_trapframe_unwind =
 261 {
 262   NORMAL_FRAME,
 263   sparc64obsd_trapframe_this_id,
 264   sparc64obsd_trapframe_prev_register
 265 };
 266
 267 static const struct frame_unwind *
 268 sparc64obsd_trapframe_sniffer (struct frame_info *next_frame)
 269 {
 270   ULONGEST pstate;
 271   char *name;
 272
 273   /* Check whether we are in privileged mode, and bail out if we're not.  */
 274   pstate = frame_unwind_register_unsigned(next_frame, SPARC64_PSTATE_REGNUM);
 275   if ((pstate & SPARC64_PSTATE_PRIV) == 0)
 276     return NULL;
 277
 278   find_pc_partial_function (frame_pc_unwind (next_frame), &name, NULL, NULL);
 279   if (name && strcmp (name, "Lslowtrap_reenter") == 0)
 280     return &sparc64obsd_trapframe_unwind;
 281
 282   return NULL;
 283 }
 284 \f
 285
 286 /* Threads support.  */
 287
 288 /* Offset wthin the thread structure where we can find %fp and %i7.  */
 289 #define SPARC64OBSD_UTHREAD_FP_OFFSET   232
 290 #define SPARC64OBSD_UTHREAD_PC_OFFSET   240
 291
 292 static void
 293 sparc64obsd_supply_uthread (struct regcache *regcache,
 294                             int regnum, CORE_ADDR addr)
 295 {
 296   CORE_ADDR fp, fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 297   gdb_byte buf[8];
 298
 299   gdb_assert (regnum >= -1);
 300
 301   fp = read_memory_unsigned_integer (fp_addr, 8);
 302   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 303     {
 304       store_unsigned_integer (buf, 8, fp);
 305       regcache_raw_supply (regcache, SPARC_SP_REGNUM, buf);
 306
 307       if (regnum == SPARC_SP_REGNUM)
 308         return;
 309     }
 310
 311   if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM
 312       || regnum == -1)
 313     {
 314       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 315
 316       i7 = read_memory_unsigned_integer (i7_addr, 8);
 317       if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 318         {
 319           store_unsigned_integer (buf, 8, i7 + 8);
 320           regcache_raw_supply (regcache, SPARC64_PC_REGNUM, buf);
 321         }
 322       if (regnum == SPARC64_NPC_REGNUM || regnum == -1)
 323         {
 324           store_unsigned_integer (buf, 8, i7 + 12);
 325           regcache_raw_supply (regcache, SPARC64_NPC_REGNUM, buf);
 326         }
 327
 328       if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM)
 329         return;
 330     }
 331
 332   sparc_supply_rwindow (regcache, fp, regnum);
 333 }
 334
 335 static void
 336 sparc64obsd_collect_uthread(const struct regcache *regcache,
 337                             int regnum, CORE_ADDR addr)
 338 {
 339   CORE_ADDR sp;
 340   gdb_byte buf[8];
 341
 342   gdb_assert (regnum >= -1);
 343
 344   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 345     {
 346       CORE_ADDR fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 347
 348       regcache_raw_collect (regcache, SPARC_SP_REGNUM, buf);
 349       write_memory (fp_addr,buf, 8);
 350     }
 351
 352   if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 353     {
 354       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 355
 356       regcache_raw_collect (regcache, SPARC64_PC_REGNUM, buf);
 357       i7 = extract_unsigned_integer (buf, 8) - 8;
 358       write_memory_unsigned_integer (i7_addr, 8, i7);
 359
 360       if (regnum == SPARC64_PC_REGNUM)
 361         return;
 362     }
 363
 364   regcache_raw_collect (regcache, SPARC_SP_REGNUM, buf);
 365   sp = extract_unsigned_integer (buf, 8);
 366   sparc_collect_rwindow (regcache, sp, regnum);
 367 }
 368 \f
 369
 370 static void
 371 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 372 {
 373   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 374
 375   tdep->gregset = regset_alloc (gdbarch, sparc64obsd_supply_gregset, NULL);
 376   tdep->sizeof_gregset = 832;
 377
 378   /* Make sure we can single-step "new" syscalls.  */
 379   tdep->step_trap = sparcnbsd_step_trap;
 380
 381   frame_unwind_append_sniffer (gdbarch, sparc64obsd_sigtramp_frame_sniffer);
 382   frame_unwind_append_sniffer (gdbarch, sparc64obsd_trapframe_sniffer);
 383
 384   sparc64_init_abi (info, gdbarch);
 385
 386   /* OpenBSD/sparc64 has SVR4-style shared libraries.  */
 387   set_solib_svr4_fetch_link_map_offsets
 388     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 389   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
 390
 391   /* OpenBSD provides a user-level threads implementation.  */
 392   bsd_uthread_set_supply_uthread (gdbarch, sparc64obsd_supply_uthread);
 393   bsd_uthread_set_collect_uthread (gdbarch, sparc64obsd_collect_uthread);
 394 }
 395 \f
 396
 397 /* Provide a prototype to silence -Wmissing-prototypes.  */
 398 void _initialize_sparc64obsd_tdep (void);
 399
 400 void
 401 _initialize_sparc64obsd_tdep (void)
 402 {
 403   gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
 404                           GDB_OSABI_OPENBSD_ELF, sparc64obsd_init_abi);
 405 }