gdb/m68klinux-tdep.c

   1 /* Motorola m68k target-dependent support for GNU/Linux.
   2
   3    Copyright 1996, 1998, 2000, 2001, 2002, 2003 Free Software Foundation,
   4    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., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, 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 \f
  37 /* Offsets (in target ints) into jmp_buf.  */
  38
  39 #define M68K_LINUX_JB_ELEMENT_SIZE 4
  40 #define M68K_LINUX_JB_PC 7
  41
  42 /* Check whether insn1 and insn2 are parts of a signal trampoline.  */
  43
  44 #define IS_SIGTRAMP(insn1, insn2)                                       \
  45   (/* addaw #20,sp; moveq #119,d0; trap #0 */                           \
  46    (insn1 == 0xdefc0014 && insn2 == 0x70774e40)                         \
  47    /* moveq #119,d0; trap #0 */                                         \
  48    || insn1 == 0x70774e40)
  49
  50 #define IS_RT_SIGTRAMP(insn1, insn2)                                    \
  51   (/* movel #173,d0; trap #0 */                                         \
  52    (insn1 == 0x203c0000 && insn2 == 0x00ad4e40)                         \
  53    /* moveq #82,d0; notb d0; trap #0 */                                 \
  54    || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
  55
  56 /* Return non-zero if PC points into the signal trampoline.  For the
  57    sake of m68k_linux_get_sigtramp_info we also distinguish between
  58    non-RT and RT signal trampolines.  */
  59
  60 static int
  61 m68k_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)
  62 {
  63   CORE_ADDR sp;
  64   char buf[12];
  65   unsigned long insn0, insn1, insn2;
  66
  67   if (read_memory_nobpt (pc - 4, buf, sizeof (buf)))
  68     return 0;
  69   insn1 = extract_unsigned_integer (buf + 4, 4);
  70   insn2 = extract_unsigned_integer (buf + 8, 4);
  71   if (IS_SIGTRAMP (insn1, insn2))
  72     return 1;
  73   if (IS_RT_SIGTRAMP (insn1, insn2))
  74     return 2;
  75
  76   insn0 = extract_unsigned_integer (buf, 4);
  77   if (IS_SIGTRAMP (insn0, insn1))
  78     return 1;
  79   if (IS_RT_SIGTRAMP (insn0, insn1))
  80     return 2;
  81
  82   insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16);
  83   insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16);
  84   if (IS_SIGTRAMP (insn0, insn1))
  85     return 1;
  86   if (IS_RT_SIGTRAMP (insn0, insn1))
  87     return 2;
  88
  89   return 0;
  90 }
  91
  92 /* From <asm/sigcontext.h>.  */
  93 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =
  94 {
  95   2 * 4,                        /* %d0 */
  96   3 * 4,                        /* %d1 */
  97   -1,                           /* %d2 */
  98   -1,                           /* %d3 */
  99   -1,                           /* %d4 */
 100   -1,                           /* %d5 */
 101   -1,                           /* %d6 */
 102   -1,                           /* %d7 */
 103   4 * 4,                        /* %a0 */
 104   5 * 4,                        /* %a1 */
 105   -1,                           /* %a2 */
 106   -1,                           /* %a3 */
 107   -1,                           /* %a4 */
 108   -1,                           /* %a5 */
 109   -1,                           /* %fp */
 110   1 * 4,                        /* %sp */
 111   5 * 4 + 2,                    /* %sr */
 112   6 * 4 + 2,                    /* %pc */
 113   8 * 4,                        /* %fp0 */
 114   11 * 4,                       /* %fp1 */
 115   -1,                           /* %fp2 */
 116   -1,                           /* %fp3 */
 117   -1,                           /* %fp4 */
 118   -1,                           /* %fp5 */
 119   -1,                           /* %fp6 */
 120   -1,                           /* %fp7 */
 121   14 * 4,                       /* %fpcr */
 122   15 * 4,                       /* %fpsr */
 123   16 * 4                        /* %fpiaddr */
 124 };
 125
 126 /* From <asm/ucontext.h>.  */
 127 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =
 128 {
 129   6 * 4,                        /* %d0 */
 130   7 * 4,                        /* %d1 */
 131   8 * 4,                        /* %d2 */
 132   9 * 4,                        /* %d3 */
 133   10 * 4,                       /* %d4 */
 134   11 * 4,                       /* %d5 */
 135   12 * 4,                       /* %d6 */
 136   13 * 4,                       /* %d7 */
 137   14 * 4,                       /* %a0 */
 138   15 * 4,                       /* %a1 */
 139   16 * 4,                       /* %a2 */
 140   17 * 4,                       /* %a3 */
 141   18 * 4,                       /* %a4 */
 142   19 * 4,                       /* %a5 */
 143   20 * 4,                       /* %fp */
 144   21 * 4,                       /* %sp */
 145   23 * 4,                       /* %sr */
 146   22 * 4,                       /* %pc */
 147   27 * 4,                       /* %fp0 */
 148   30 * 4,                       /* %fp1 */
 149   33 * 4,                       /* %fp2 */
 150   36 * 4,                       /* %fp3 */
 151   39 * 4,                       /* %fp4 */
 152   42 * 4,                       /* %fp5 */
 153   45 * 4,                       /* %fp6 */
 154   48 * 4,                       /* %fp7 */
 155   24 * 4,                       /* %fpcr */
 156   25 * 4,                       /* %fpsr */
 157   26 * 4                        /* %fpiaddr */
 158 };
 159
 160
 161 /* Get info about saved registers in sigtramp.  */
 162
 163 static struct m68k_sigtramp_info
 164 m68k_linux_get_sigtramp_info (struct frame_info *next_frame)
 165 {
 166   CORE_ADDR sp;
 167   char buf[4];
 168   struct m68k_sigtramp_info info;
 169
 170   frame_unwind_register (next_frame, M68K_SP_REGNUM, buf);
 171   sp = extract_unsigned_integer (buf, 4);
 172
 173   /* Get sigcontext address, it is the third parameter on the stack.  */
 174   info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4);
 175
 176   if (m68k_linux_pc_in_sigtramp (frame_pc_unwind (next_frame), 0) == 2)
 177     info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
 178   else
 179     info.sc_reg_offset = m68k_linux_sigcontext_reg_offset;
 180   return info;
 181 }
 182
 183 /* Extract from an array REGBUF containing the (raw) register state, a
 184    function return value of TYPE, and copy that, in virtual format,
 185    into VALBUF.  */
 186
 187 static void
 188 m68k_linux_extract_return_value (struct type *type, struct regcache *regcache,
 189                                  void *valbuf)
 190 {
 191   int len = TYPE_LENGTH (type);
 192   char buf[M68K_MAX_REGISTER_SIZE];
 193
 194   if (TYPE_CODE (type) == TYPE_CODE_STRUCT
 195       && TYPE_NFIELDS (type) == 1)
 196     {
 197       m68k_linux_extract_return_value (TYPE_FIELD_TYPE (type, 0), regcache,
 198                                        valbuf);
 199       return;
 200     }
 201
 202   if (TYPE_CODE (type) == TYPE_CODE_FLT)
 203     {
 204       regcache_raw_read (regcache, M68K_FP0_REGNUM, buf);
 205       convert_typed_floating (buf, builtin_type_m68881_ext, valbuf, type);
 206     }
 207   else if (TYPE_CODE (type) == TYPE_CODE_PTR)
 208     regcache_raw_read (regcache, M68K_A0_REGNUM, valbuf);
 209   else
 210     {
 211       if (len <= 4)
 212         {
 213           regcache_raw_read (regcache, M68K_D0_REGNUM, buf);
 214           memcpy (valbuf, buf + (4 - len), len);
 215         }
 216       else if (len <= 8)
 217         {
 218           regcache_raw_read (regcache, M68K_D0_REGNUM, buf);
 219           memcpy (valbuf, buf + (8 - len), len - 4);
 220           regcache_raw_read (regcache, M68K_D1_REGNUM,
 221                              (char *) valbuf + (len - 4));
 222         }
 223       else
 224         internal_error (__FILE__, __LINE__,
 225                         "Cannot extract return value of %d bytes long.", len);
 226     }
 227 }
 228
 229 /* Write into the appropriate registers a function return value stored
 230    in VALBUF of type TYPE, given in virtual format.  */
 231
 232 static void
 233 m68k_linux_store_return_value (struct type *type, struct regcache *regcache,
 234                                const void *valbuf)
 235 {
 236   int len = TYPE_LENGTH (type);
 237
 238   if (TYPE_CODE (type) == TYPE_CODE_STRUCT
 239       && TYPE_NFIELDS (type) == 1)
 240     {
 241       m68k_linux_store_return_value (TYPE_FIELD_TYPE (type, 0), regcache,
 242                                      valbuf);
 243       return;
 244     }
 245
 246   if (TYPE_CODE (type) == TYPE_CODE_FLT)
 247     {
 248       char buf[M68K_MAX_REGISTER_SIZE];
 249       convert_typed_floating (valbuf, type, buf, builtin_type_m68881_ext);
 250       regcache_raw_write (regcache, M68K_FP0_REGNUM, buf);
 251     }
 252   else if (TYPE_CODE (type) == TYPE_CODE_PTR)
 253     regcache_raw_write (regcache, M68K_A0_REGNUM, valbuf);
 254   else
 255     {
 256       if (len <= 4)
 257         regcache_raw_write_part (regcache, M68K_D0_REGNUM,
 258                                  4 - len, len, valbuf);
 259       else if (len <= 8)
 260         {
 261           regcache_raw_write_part (regcache, M68K_D1_REGNUM, 8 - len,
 262                                    len - 4, valbuf);
 263           regcache_raw_write (regcache, M68K_D0_REGNUM,
 264                               (char *) valbuf + (len - 4));
 265         }
 266       else
 267         internal_error (__FILE__, __LINE__,
 268                         "Cannot store return value of %d bytes long.", len);
 269     }
 270 }
 271
 272 /* Extract from an array REGBUF containing the (raw) register state
 273    the address in which a function should return its structure value,
 274    as a CORE_ADDR.  */
 275
 276 static CORE_ADDR
 277 m68k_linux_extract_struct_value_address (struct regcache *regcache)
 278 {
 279   char buf[4];
 280
 281   regcache_cooked_read (regcache, M68K_A0_REGNUM, buf);
 282   return extract_unsigned_integer (buf, 4);
 283 }
 284
 285 static void
 286 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 287 {
 288   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 289
 290   tdep->jb_pc = M68K_LINUX_JB_PC;
 291   tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
 292   tdep->get_sigtramp_info = m68k_linux_get_sigtramp_info;
 293   tdep->struct_return = reg_struct_return;
 294
 295   set_gdbarch_extract_return_value (gdbarch, m68k_linux_extract_return_value);
 296   set_gdbarch_store_return_value (gdbarch, m68k_linux_store_return_value);
 297   set_gdbarch_extract_struct_value_address (gdbarch,
 298                                             m68k_linux_extract_struct_value_address);
 299
 300   set_gdbarch_pc_in_sigtramp (gdbarch, m68k_linux_pc_in_sigtramp);
 301
 302   /* Shared library handling.  */
 303   set_gdbarch_in_solib_call_trampoline (gdbarch, in_plt_section);
 304   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 305 }
 306
 307 void
 308 _initialize_m68k_linux_tdep (void)
 309 {
 310   gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
 311                           m68k_linux_init_abi);
 312 }