gnu/dist/gdb6/gdb/sparc64obsd-tdep.c

   1 /* Target-dependent code for OpenBSD/sparc64.
   2
   3    Copyright (C) 2004, 2005, 2006 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
 206 /* Threads support.  */
 207
 208 /* Offset wthin the thread structure where we can find %fp and %i7.  */
 209 #define SPARC64OBSD_UTHREAD_FP_OFFSET   232
 210 #define SPARC64OBSD_UTHREAD_PC_OFFSET   240
 211
 212 static void
 213 sparc64obsd_supply_uthread (struct regcache *regcache,
 214                             int regnum, CORE_ADDR addr)
 215 {
 216   CORE_ADDR fp, fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 217   gdb_byte buf[8];
 218
 219   gdb_assert (regnum >= -1);
 220
 221   fp = read_memory_unsigned_integer (fp_addr, 8);
 222   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 223     {
 224       store_unsigned_integer (buf, 8, fp);
 225       regcache_raw_supply (regcache, SPARC_SP_REGNUM, buf);
 226
 227       if (regnum == SPARC_SP_REGNUM)
 228         return;
 229     }
 230
 231   if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM
 232       || regnum == -1)
 233     {
 234       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 235
 236       i7 = read_memory_unsigned_integer (i7_addr, 8);
 237       if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 238         {
 239           store_unsigned_integer (buf, 8, i7 + 8);
 240           regcache_raw_supply (regcache, SPARC64_PC_REGNUM, buf);
 241         }
 242       if (regnum == SPARC64_NPC_REGNUM || regnum == -1)
 243         {
 244           store_unsigned_integer (buf, 8, i7 + 12);
 245           regcache_raw_supply (regcache, SPARC64_NPC_REGNUM, buf);
 246         }
 247
 248       if (regnum == SPARC64_PC_REGNUM || regnum == SPARC64_NPC_REGNUM)
 249         return;
 250     }
 251
 252   sparc_supply_rwindow (regcache, fp, regnum);
 253 }
 254
 255 static void
 256 sparc64obsd_collect_uthread(const struct regcache *regcache,
 257                             int regnum, CORE_ADDR addr)
 258 {
 259   CORE_ADDR sp;
 260   gdb_byte buf[8];
 261
 262   gdb_assert (regnum >= -1);
 263
 264   if (regnum == SPARC_SP_REGNUM || regnum == -1)
 265     {
 266       CORE_ADDR fp_addr = addr + SPARC64OBSD_UTHREAD_FP_OFFSET;
 267
 268       regcache_raw_collect (regcache, SPARC_SP_REGNUM, buf);
 269       write_memory (fp_addr,buf, 8);
 270     }
 271
 272   if (regnum == SPARC64_PC_REGNUM || regnum == -1)
 273     {
 274       CORE_ADDR i7, i7_addr = addr + SPARC64OBSD_UTHREAD_PC_OFFSET;
 275
 276       regcache_raw_collect (regcache, SPARC64_PC_REGNUM, buf);
 277       i7 = extract_unsigned_integer (buf, 8) - 8;
 278       write_memory_unsigned_integer (i7_addr, 8, i7);
 279
 280       if (regnum == SPARC64_PC_REGNUM)
 281         return;
 282     }
 283
 284   regcache_raw_collect (regcache, SPARC_SP_REGNUM, buf);
 285   sp = extract_unsigned_integer (buf, 8);
 286   sparc_collect_rwindow (regcache, sp, regnum);
 287 }
 288 \f
 289
 290 static void
 291 sparc64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 292 {
 293   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 294
 295   tdep->gregset = regset_alloc (gdbarch, sparc64obsd_supply_gregset, NULL);
 296   tdep->sizeof_gregset = 832;
 297
 298   /* Make sure we can single-step "new" syscalls.  */
 299   tdep->step_trap = sparcnbsd_step_trap;
 300
 301   frame_unwind_append_sniffer (gdbarch, sparc64obsd_sigtramp_frame_sniffer);
 302
 303   sparc64_init_abi (info, gdbarch);
 304
 305   /* OpenBSD/sparc64 has SVR4-style shared libraries.  */
 306   set_solib_svr4_fetch_link_map_offsets
 307     (gdbarch, svr4_lp64_fetch_link_map_offsets);
 308   set_gdbarch_skip_solib_resolver (gdbarch, obsd_skip_solib_resolver);
 309
 310   /* OpenBSD provides a user-level threads implementation.  */
 311   bsd_uthread_set_supply_uthread (gdbarch, sparc64obsd_supply_uthread);
 312   bsd_uthread_set_collect_uthread (gdbarch, sparc64obsd_collect_uthread);
 313 }
 314 \f
 315
 316 /* Provide a prototype to silence -Wmissing-prototypes.  */
 317 void _initialize_sparc64obsd_tdep (void);
 318
 319 void
 320 _initialize_sparc64obsd_tdep (void)
 321 {
 322   gdbarch_register_osabi (bfd_arch_sparc, bfd_mach_sparc_v9,
 323                           GDB_OSABI_OPENBSD_ELF, sparc64obsd_init_abi);
 324 }