gdb/m68klinux-tdep.c

   1 /* Motorola m68k target-dependent support for GNU/Linux.
   2
   3    Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2007
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "defs.h"
  24 #include "gdbcore.h"
  25 #include "doublest.h"
  26 #include "floatformat.h"
  27 #include "frame.h"
  28 #include "target.h"
  29 #include "gdb_string.h"
  30 #include "gdbtypes.h"
  31 #include "osabi.h"
  32 #include "regcache.h"
  33 #include "objfiles.h"
  34 #include "symtab.h"
  35 #include "m68k-tdep.h"
  36 #include "trad-frame.h"
  37 #include "frame-unwind.h"
  38 #include "glibc-tdep.h"
  39 #include "solib-svr4.h"
  40 \f
  41 /* Offsets (in target ints) into jmp_buf.  */
  42
  43 #define M68K_LINUX_JB_ELEMENT_SIZE 4
  44 #define M68K_LINUX_JB_PC 7
  45
  46 /* Check whether insn1 and insn2 are parts of a signal trampoline.  */
  47
  48 #define IS_SIGTRAMP(insn1, insn2)                                       \
  49   (/* addaw #20,sp; moveq #119,d0; trap #0 */                           \
  50    (insn1 == 0xdefc0014 && insn2 == 0x70774e40)                         \
  51    /* moveq #119,d0; trap #0 */                                         \
  52    || insn1 == 0x70774e40)
  53
  54 #define IS_RT_SIGTRAMP(insn1, insn2)                                    \
  55   (/* movel #173,d0; trap #0 */                                         \
  56    (insn1 == 0x203c0000 && insn2 == 0x00ad4e40)                         \
  57    /* moveq #82,d0; notb d0; trap #0 */                                 \
  58    || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
  59
  60 /* Return non-zero if PC points into the signal trampoline.  For the
  61    sake of m68k_linux_get_sigtramp_info we also distinguish between
  62    non-RT and RT signal trampolines.  */
  63
  64 static int
  65 m68k_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)
  66 {
  67   CORE_ADDR sp;
  68   char buf[12];
  69   unsigned long insn0, insn1, insn2;
  70
  71   if (read_memory_nobpt (pc - 4, buf, sizeof (buf)))
  72     return 0;
  73   insn1 = extract_unsigned_integer (buf + 4, 4);
  74   insn2 = extract_unsigned_integer (buf + 8, 4);
  75   if (IS_SIGTRAMP (insn1, insn2))
  76     return 1;
  77   if (IS_RT_SIGTRAMP (insn1, insn2))
  78     return 2;
  79
  80   insn0 = extract_unsigned_integer (buf, 4);
  81   if (IS_SIGTRAMP (insn0, insn1))
  82     return 1;
  83   if (IS_RT_SIGTRAMP (insn0, insn1))
  84     return 2;
  85
  86   insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16);
  87   insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16);
  88   if (IS_SIGTRAMP (insn0, insn1))
  89     return 1;
  90   if (IS_RT_SIGTRAMP (insn0, insn1))
  91     return 2;
  92
  93   return 0;
  94 }
  95
  96 /* From <asm/sigcontext.h>.  */
  97 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =
  98 {
  99   2 * 4,                        /* %d0 */
 100   3 * 4,                        /* %d1 */
 101   -1,                           /* %d2 */
 102   -1,                           /* %d3 */
 103   -1,                           /* %d4 */
 104   -1,                           /* %d5 */
 105   -1,                           /* %d6 */
 106   -1,                           /* %d7 */
 107   4 * 4,                        /* %a0 */
 108   5 * 4,                        /* %a1 */
 109   -1,                           /* %a2 */
 110   -1,                           /* %a3 */
 111   -1,                           /* %a4 */
 112   -1,                           /* %a5 */
 113   -1,                           /* %fp */
 114   1 * 4,                        /* %sp */
 115   5 * 4 + 2,                    /* %sr */
 116   6 * 4 + 2,                    /* %pc */
 117   8 * 4,                        /* %fp0 */
 118   11 * 4,                       /* %fp1 */
 119   -1,                           /* %fp2 */
 120   -1,                           /* %fp3 */
 121   -1,                           /* %fp4 */
 122   -1,                           /* %fp5 */
 123   -1,                           /* %fp6 */
 124   -1,                           /* %fp7 */
 125   14 * 4,                       /* %fpcr */
 126   15 * 4,                       /* %fpsr */
 127   16 * 4                        /* %fpiaddr */
 128 };
 129
 130 /* From <asm/ucontext.h>.  */
 131 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =
 132 {
 133   6 * 4,                        /* %d0 */
 134   7 * 4,                        /* %d1 */
 135   8 * 4,                        /* %d2 */
 136   9 * 4,                        /* %d3 */
 137   10 * 4,                       /* %d4 */
 138   11 * 4,                       /* %d5 */
 139   12 * 4,                       /* %d6 */
 140   13 * 4,                       /* %d7 */
 141   14 * 4,                       /* %a0 */
 142   15 * 4,                       /* %a1 */
 143   16 * 4,                       /* %a2 */
 144   17 * 4,                       /* %a3 */
 145   18 * 4,                       /* %a4 */
 146   19 * 4,                       /* %a5 */
 147   20 * 4,                       /* %fp */
 148   21 * 4,                       /* %sp */
 149   23 * 4,                       /* %sr */
 150   22 * 4,                       /* %pc */
 151   27 * 4,                       /* %fp0 */
 152   30 * 4,                       /* %fp1 */
 153   33 * 4,                       /* %fp2 */
 154   36 * 4,                       /* %fp3 */
 155   39 * 4,                       /* %fp4 */
 156   42 * 4,                       /* %fp5 */
 157   45 * 4,                       /* %fp6 */
 158   48 * 4,                       /* %fp7 */
 159   24 * 4,                       /* %fpcr */
 160   25 * 4,                       /* %fpsr */
 161   26 * 4                        /* %fpiaddr */
 162 };
 163
 164
 165 /* Get info about saved registers in sigtramp.  */
 166
 167 struct m68k_linux_sigtramp_info
 168 {
 169   /* Address of sigcontext.  */
 170   CORE_ADDR sigcontext_addr;
 171
 172   /* Offset of registers in `struct sigcontext'.  */
 173   int *sc_reg_offset;
 174 };
 175
 176 static struct m68k_linux_sigtramp_info
 177 m68k_linux_get_sigtramp_info (struct frame_info *next_frame)
 178 {
 179   CORE_ADDR sp;
 180   char buf[4];
 181   struct m68k_linux_sigtramp_info info;
 182
 183   frame_unwind_register (next_frame, M68K_SP_REGNUM, buf);
 184   sp = extract_unsigned_integer (buf, 4);
 185
 186   /* Get sigcontext address, it is the third parameter on the stack.  */
 187   info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4);
 188
 189   if (m68k_linux_pc_in_sigtramp (frame_pc_unwind (next_frame), 0) == 2)
 190     info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
 191   else
 192     info.sc_reg_offset = m68k_linux_sigcontext_reg_offset;
 193   return info;
 194 }
 195
 196 /* Signal trampolines.  */
 197
 198 static struct trad_frame_cache *
 199 m68k_linux_sigtramp_frame_cache (struct frame_info *next_frame,
 200                                  void **this_cache)
 201 {
 202   struct frame_id this_id;
 203   struct trad_frame_cache *cache;
 204   struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
 205   struct m68k_linux_sigtramp_info info;
 206   char buf[4];
 207   int i;
 208
 209   if (*this_cache)
 210     return *this_cache;
 211
 212   cache = trad_frame_cache_zalloc (next_frame);
 213
 214   /* FIXME: cagney/2004-05-01: This is is long standing broken code.
 215      The frame ID's code address should be the start-address of the
 216      signal trampoline and not the current PC within that
 217      trampoline.  */
 218   frame_unwind_register (next_frame, M68K_SP_REGNUM, buf);
 219   /* See the end of m68k_push_dummy_call.  */
 220   this_id = frame_id_build (extract_unsigned_integer (buf, 4) - 4 + 8,
 221                             frame_pc_unwind (next_frame));
 222   trad_frame_set_id (cache, this_id);
 223
 224   info = m68k_linux_get_sigtramp_info (next_frame);
 225
 226   for (i = 0; i < M68K_NUM_REGS; i++)
 227     if (info.sc_reg_offset[i] != -1)
 228       trad_frame_set_reg_addr (cache, i,
 229                                info.sigcontext_addr + info.sc_reg_offset[i]);
 230
 231   *this_cache = cache;
 232   return cache;
 233 }
 234
 235 static void
 236 m68k_linux_sigtramp_frame_this_id (struct frame_info *next_frame,
 237                                    void **this_cache,
 238                                    struct frame_id *this_id)
 239 {
 240   struct trad_frame_cache *cache =
 241     m68k_linux_sigtramp_frame_cache (next_frame, this_cache);
 242   trad_frame_get_id (cache, this_id);
 243 }
 244
 245 static void
 246 m68k_linux_sigtramp_frame_prev_register (struct frame_info *next_frame,
 247                                          void **this_cache,
 248                                          int regnum, int *optimizedp,
 249                                          enum lval_type *lvalp,
 250                                          CORE_ADDR *addrp,
 251                                          int *realnump, gdb_byte *valuep)
 252 {
 253   /* Make sure we've initialized the cache.  */
 254   struct trad_frame_cache *cache =
 255     m68k_linux_sigtramp_frame_cache (next_frame, this_cache);
 256   trad_frame_get_register (cache, next_frame, regnum, optimizedp, lvalp,
 257                            addrp, realnump, valuep);
 258 }
 259
 260 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
 261 {
 262   SIGTRAMP_FRAME,
 263   m68k_linux_sigtramp_frame_this_id,
 264   m68k_linux_sigtramp_frame_prev_register
 265 };
 266
 267 static const struct frame_unwind *
 268 m68k_linux_sigtramp_frame_sniffer (struct frame_info *next_frame)
 269 {
 270   CORE_ADDR pc = frame_pc_unwind (next_frame);
 271   char *name;
 272
 273   find_pc_partial_function (pc, &name, NULL, NULL);
 274   if (m68k_linux_pc_in_sigtramp (pc, name))
 275     return &m68k_linux_sigtramp_frame_unwind;
 276
 277   return NULL;
 278 }
 279
 280 static void
 281 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 282 {
 283   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 284
 285   tdep->jb_pc = M68K_LINUX_JB_PC;
 286   tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
 287
 288   /* GNU/Linux uses a calling convention that's similar to SVR4.  It
 289      returns integer values in %d0/%d1, pointer values in %a0 and
 290      floating values in %fp0, just like SVR4, but uses %a1 to pass the
 291      address to store a structure value.  It also returns small
 292      structures in registers instead of memory.  */
 293   m68k_svr4_init_abi (info, gdbarch);
 294   tdep->struct_value_regnum = M68K_A1_REGNUM;
 295   tdep->struct_return = reg_struct_return;
 296
 297   frame_unwind_append_sniffer (gdbarch, m68k_linux_sigtramp_frame_sniffer);
 298
 299   /* Shared library handling.  */
 300
 301   /* GNU/Linux uses SVR4-style shared libraries.  */
 302   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 303                                          svr4_ilp32_fetch_link_map_offsets);
 304
 305   /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
 306   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
 307
 308   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 309
 310   /* Enable TLS support.  */
 311   set_gdbarch_fetch_tls_load_module_address (gdbarch,
 312                                              svr4_fetch_objfile_link_map);
 313 }
 314
 315 void
 316 _initialize_m68k_linux_tdep (void)
 317 {
 318   gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
 319                           m68k_linux_init_abi);
 320 }