gdb/m68kbsd-tdep.c

   1 /* Target-dependent code for Motorola 68000 BSD's.
   2
   3    Copyright (C) 2004, 2005, 2007, 2008 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 "arch-utils.h"
  22 #include "frame.h"
  23 #include "osabi.h"
  24 #include "regcache.h"
  25 #include "regset.h"
  26 #include "trad-frame.h"
  27 #include "tramp-frame.h"
  28 #include "gdbtypes.h"
  29
  30 #include "gdb_assert.h"
  31 #include "gdb_string.h"
  32
  33 #include "m68k-tdep.h"
  34 #include "solib-svr4.h"
  35
  36 /* Core file support.  */
  37
  38 /* Sizeof `struct reg' in <machine/reg.h>.  */
  39 #define M68KBSD_SIZEOF_GREGS    (18 * 4)
  40
  41 /* Sizeof `struct fpreg' in <machine/reg.h.  */
  42 #define M68KBSD_SIZEOF_FPREGS   (((8 * 3) + 3) * 4)
  43
  44 int
  45 m68kbsd_fpreg_offset (int regnum)
  46 {
  47   int fp_len = TYPE_LENGTH (gdbarch_register_type (current_gdbarch, regnum));
  48
  49   if (regnum >= M68K_FPC_REGNUM)
  50     return 8 * fp_len + (regnum - M68K_FPC_REGNUM) * 4;
  51
  52   return (regnum - M68K_FP0_REGNUM) * fp_len;
  53 }
  54
  55 /* Supply register REGNUM from the buffer specified by FPREGS and LEN
  56    in the floating-point register set REGSET to register cache
  57    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */
  58
  59 static void
  60 m68kbsd_supply_fpregset (const struct regset *regset,
  61                          struct regcache *regcache,
  62                          int regnum, const void *fpregs, size_t len)
  63 {
  64   const gdb_byte *regs = fpregs;
  65   int i;
  66
  67   gdb_assert (len >= M68KBSD_SIZEOF_FPREGS);
  68
  69   for (i = M68K_FP0_REGNUM; i <= M68K_PC_REGNUM; i++)
  70     {
  71       if (regnum == i || regnum == -1)
  72         regcache_raw_supply (regcache, i, regs + m68kbsd_fpreg_offset (i));
  73     }
  74 }
  75
  76 /* Supply register REGNUM from the buffer specified by GREGS and LEN
  77    in the general-purpose register set REGSET to register cache
  78    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */
  79
  80 static void
  81 m68kbsd_supply_gregset (const struct regset *regset,
  82                         struct regcache *regcache,
  83                         int regnum, const void *gregs, size_t len)
  84 {
  85   const gdb_byte *regs = gregs;
  86   int i;
  87
  88   gdb_assert (len >= M68KBSD_SIZEOF_GREGS);
  89
  90   for (i = M68K_D0_REGNUM; i <= M68K_PC_REGNUM; i++)
  91     {
  92       if (regnum == i || regnum == -1)
  93         regcache_raw_supply (regcache, i, regs + i * 4);
  94     }
  95
  96   if (len >= M68KBSD_SIZEOF_GREGS + M68KBSD_SIZEOF_FPREGS)
  97     {
  98       regs += M68KBSD_SIZEOF_GREGS;
  99       len -= M68KBSD_SIZEOF_GREGS;
 100       m68kbsd_supply_fpregset (regset, regcache, regnum, regs, len);
 101     }
 102 }
 103
 104 /* Motorola 68000 register sets.  */
 105
 106 static struct regset m68kbsd_gregset =
 107 {
 108   NULL,
 109   m68kbsd_supply_gregset
 110 };
 111
 112 static struct regset m68kbsd_fpregset =
 113 {
 114   NULL,
 115   m68kbsd_supply_fpregset
 116 };
 117
 118 /* Return the appropriate register set for the core section identified
 119    by SECT_NAME and SECT_SIZE.  */
 120
 121 static const struct regset *
 122 m68kbsd_regset_from_core_section (struct gdbarch *gdbarch,
 123                                   const char *sect_name, size_t sect_size)
 124 {
 125   if (strcmp (sect_name, ".reg") == 0 && sect_size >= M68KBSD_SIZEOF_GREGS)
 126     return &m68kbsd_gregset;
 127
 128   if (strcmp (sect_name, ".reg2") == 0 && sect_size >= M68KBSD_SIZEOF_FPREGS)
 129     return &m68kbsd_fpregset;
 130
 131   return NULL;
 132 }
 133 \f
 134
 135 /* Signal trampolines.  */
 136
 137 static void
 138 m68kobsd_sigtramp_cache_init (const struct tramp_frame *self,
 139                               struct frame_info *next_frame,
 140                               struct trad_frame_cache *this_cache,
 141                               CORE_ADDR func)
 142 {
 143   CORE_ADDR addr, base, pc;
 144   int regnum;
 145
 146   base = frame_unwind_register_unsigned (next_frame, M68K_SP_REGNUM);
 147
 148   /* The 'addql #4,%sp' instruction at offset 8 adjusts the stack
 149      pointer.  Adjust the frame base accordingly.  */
 150   pc = frame_unwind_register_unsigned (next_frame, M68K_PC_REGNUM);
 151   if ((pc - func) > 8)
 152     base -= 4;
 153
 154   /* Get frame pointer, stack pointer, program counter and processor
 155      state from `struct sigcontext'.  */
 156   addr = get_frame_memory_unsigned (next_frame, base + 8, 4);
 157   trad_frame_set_reg_addr (this_cache, M68K_FP_REGNUM, addr + 8);
 158   trad_frame_set_reg_addr (this_cache, M68K_SP_REGNUM, addr + 12);
 159   trad_frame_set_reg_addr (this_cache, M68K_PC_REGNUM, addr + 20);
 160   trad_frame_set_reg_addr (this_cache, M68K_PS_REGNUM, addr + 24);
 161
 162   /* The sc_ap member of `struct sigcontext' points to additional
 163      hardware state.  Here we find the missing registers.  */
 164   addr = get_frame_memory_unsigned (next_frame, addr + 16, 4) + 4;
 165   for (regnum = M68K_D0_REGNUM; regnum < M68K_FP_REGNUM; regnum++, addr += 4)
 166     trad_frame_set_reg_addr (this_cache, regnum, addr);
 167
 168   /* Construct the frame ID using the function start.  */
 169   trad_frame_set_id (this_cache, frame_id_build (base, func));
 170 }
 171
 172 static const struct tramp_frame m68kobsd_sigtramp = {
 173   SIGTRAMP_FRAME,
 174   2,
 175   {
 176     { 0x206f, -1 }, { 0x000c, -1},      /* moveal %sp@(12),%a0 */
 177     { 0x4e90, -1 },                     /* jsr %a0@ */
 178     { 0x588f, -1 },                     /* addql #4,%sp */
 179     { 0x4e41, -1 },                     /* trap #1 */
 180     { 0x2f40, -1 }, { 0x0004, -1 },     /* moveal %d0,%sp@(4) */
 181     { 0x7001, -1 },                     /* moveq #SYS_exit,%d0 */
 182     { 0x4e40, -1 },                     /* trap #0 */
 183     { TRAMP_SENTINEL_INSN, -1 }
 184   },
 185   m68kobsd_sigtramp_cache_init
 186 };
 187 \f
 188
 189 static void
 190 m68kbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 191 {
 192   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 193
 194   tdep->jb_pc = 5;
 195   tdep->jb_elt_size = 4;
 196
 197   set_gdbarch_decr_pc_after_break (gdbarch, 2);
 198
 199   set_gdbarch_regset_from_core_section
 200     (gdbarch, m68kbsd_regset_from_core_section);
 201 }
 202
 203 /* OpenBSD and NetBSD a.out.  */
 204
 205 static void
 206 m68kbsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 207 {
 208   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 209
 210   m68kbsd_init_abi (info, gdbarch);
 211
 212   tdep->struct_return = reg_struct_return;
 213
 214   tramp_frame_prepend_unwinder (gdbarch, &m68kobsd_sigtramp);
 215 }
 216
 217 /* NetBSD ELF.  */
 218
 219 static void
 220 m68kbsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 221 {
 222   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 223
 224   m68kbsd_init_abi (info, gdbarch);
 225
 226   /* NetBSD ELF uses the SVR4 ABI.  */
 227   m68k_svr4_init_abi (info, gdbarch);
 228   tdep->struct_return = pcc_struct_return;
 229
 230   /* NetBSD ELF uses SVR4-style shared libraries.  */
 231   set_solib_svr4_fetch_link_map_offsets
 232     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 233 }
 234 \f
 235
 236 static enum gdb_osabi
 237 m68kbsd_aout_osabi_sniffer (bfd *abfd)
 238 {
 239   if (strcmp (bfd_get_target (abfd), "a.out-m68k-netbsd") == 0
 240       || strcmp (bfd_get_target (abfd), "a.out-m68k4k-netbsd") == 0)
 241     return GDB_OSABI_NETBSD_AOUT;
 242
 243   return GDB_OSABI_UNKNOWN;
 244 }
 245
 246 static enum gdb_osabi
 247 m68kbsd_core_osabi_sniffer (bfd *abfd)
 248 {
 249   if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
 250     return GDB_OSABI_NETBSD_AOUT;
 251
 252   return GDB_OSABI_UNKNOWN;
 253 }
 254 \f
 255
 256 /* Provide a prototype to silence -Wmissing-prototypes.  */
 257 void _initialize_m68kbsd_tdep (void);
 258
 259 void
 260 _initialize_m68kbsd_tdep (void)
 261 {
 262   gdbarch_register_osabi_sniffer (bfd_arch_m68k, bfd_target_aout_flavour,
 263                                   m68kbsd_aout_osabi_sniffer);
 264
 265   /* BFD doesn't set a flavour for NetBSD style a.out core files.  */
 266   gdbarch_register_osabi_sniffer (bfd_arch_m68k, bfd_target_unknown_flavour,
 267                                   m68kbsd_core_osabi_sniffer);
 268
 269   gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_NETBSD_AOUT,
 270                           m68kbsd_aout_init_abi);
 271   gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_NETBSD_ELF,
 272                           m68kbsd_elf_init_abi);
 273 }