gdb/m68kbsd-tdep.c

   1 /* Target-dependent code for Motorola 68000 BSD's.
   2
   3    Copyright (C) 2004-2016 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 "m68k-tdep.h"
  31 #include "solib-svr4.h"
  32
  33 /* Core file support.  */
  34
  35 /* Sizeof `struct reg' in <machine/reg.h>.  */
  36 #define M68KBSD_SIZEOF_GREGS    (18 * 4)
  37
  38 /* Sizeof `struct fpreg' in <machine/reg.h.  */
  39 #define M68KBSD_SIZEOF_FPREGS   (((8 * 3) + 3) * 4)
  40
  41 int
  42 m68kbsd_fpreg_offset (struct gdbarch *gdbarch, int regnum)
  43 {
  44   int fp_len = TYPE_LENGTH (gdbarch_register_type (gdbarch, regnum));
  45
  46   if (regnum >= M68K_FPC_REGNUM)
  47     return 8 * fp_len + (regnum - M68K_FPC_REGNUM) * 4;
  48
  49   return (regnum - M68K_FP0_REGNUM) * fp_len;
  50 }
  51
  52 /* Supply register REGNUM from the buffer specified by FPREGS and LEN
  53    in the floating-point register set REGSET to register cache
  54    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */
  55
  56 static void
  57 m68kbsd_supply_fpregset (const struct regset *regset,
  58                          struct regcache *regcache,
  59                          int regnum, const void *fpregs, size_t len)
  60 {
  61   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  62   const gdb_byte *regs = (const gdb_byte *) fpregs;
  63   int i;
  64
  65   gdb_assert (len >= M68KBSD_SIZEOF_FPREGS);
  66
  67   for (i = M68K_FP0_REGNUM; i <= M68K_PC_REGNUM; i++)
  68     {
  69       if (regnum == i || regnum == -1)
  70         regcache_raw_supply (regcache, i,
  71                              regs + m68kbsd_fpreg_offset (gdbarch, i));
  72     }
  73 }
  74
  75 /* Supply register REGNUM from the buffer specified by GREGS and LEN
  76    in the general-purpose register set REGSET to register cache
  77    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */
  78
  79 static void
  80 m68kbsd_supply_gregset (const struct regset *regset,
  81                         struct regcache *regcache,
  82                         int regnum, const void *gregs, size_t len)
  83 {
  84   const gdb_byte *regs = (const gdb_byte *) gregs;
  85   int i;
  86
  87   gdb_assert (len >= M68KBSD_SIZEOF_GREGS);
  88
  89   for (i = M68K_D0_REGNUM; i <= M68K_PC_REGNUM; i++)
  90     {
  91       if (regnum == i || regnum == -1)
  92         regcache_raw_supply (regcache, i, regs + i * 4);
  93     }
  94
  95   if (len >= M68KBSD_SIZEOF_GREGS + M68KBSD_SIZEOF_FPREGS)
  96     {
  97       regs += M68KBSD_SIZEOF_GREGS;
  98       len -= M68KBSD_SIZEOF_GREGS;
  99       m68kbsd_supply_fpregset (regset, regcache, regnum, regs, len);
 100     }
 101 }
 102
 103 /* Motorola 68000 register sets.  */
 104
 105 static const struct regset m68kbsd_gregset =
 106 {
 107   NULL,
 108   m68kbsd_supply_gregset,
 109   NULL,
 110   REGSET_VARIABLE_SIZE
 111 };
 112
 113 static const struct regset m68kbsd_fpregset =
 114 {
 115   NULL,
 116   m68kbsd_supply_fpregset
 117 };
 118
 119 /* Iterate over core file register note sections.  */
 120
 121 static void
 122 m68kbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
 123                                       iterate_over_regset_sections_cb *cb,
 124                                       void *cb_data,
 125                                       const struct regcache *regcache)
 126 {
 127   cb (".reg", M68KBSD_SIZEOF_GREGS, &m68kbsd_gregset, NULL, cb_data);
 128   cb (".reg2", M68KBSD_SIZEOF_FPREGS, &m68kbsd_fpregset, NULL, cb_data);
 129 }
 130 \f
 131
 132 /* Signal trampolines.  */
 133
 134 static void
 135 m68kobsd_sigtramp_cache_init (const struct tramp_frame *self,
 136                               struct frame_info *this_frame,
 137                               struct trad_frame_cache *this_cache,
 138                               CORE_ADDR func)
 139 {
 140   CORE_ADDR addr, base, pc;
 141   int regnum;
 142
 143   base = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM);
 144
 145   /* The 'addql #4,%sp' instruction at offset 8 adjusts the stack
 146      pointer.  Adjust the frame base accordingly.  */
 147   pc = get_frame_register_unsigned (this_frame, M68K_PC_REGNUM);
 148   if ((pc - func) > 8)
 149     base -= 4;
 150
 151   /* Get frame pointer, stack pointer, program counter and processor
 152      state from `struct sigcontext'.  */
 153   addr = get_frame_memory_unsigned (this_frame, base + 8, 4);
 154   trad_frame_set_reg_addr (this_cache, M68K_FP_REGNUM, addr + 8);
 155   trad_frame_set_reg_addr (this_cache, M68K_SP_REGNUM, addr + 12);
 156   trad_frame_set_reg_addr (this_cache, M68K_PC_REGNUM, addr + 20);
 157   trad_frame_set_reg_addr (this_cache, M68K_PS_REGNUM, addr + 24);
 158
 159   /* The sc_ap member of `struct sigcontext' points to additional
 160      hardware state.  Here we find the missing registers.  */
 161   addr = get_frame_memory_unsigned (this_frame, addr + 16, 4) + 4;
 162   for (regnum = M68K_D0_REGNUM; regnum < M68K_FP_REGNUM; regnum++, addr += 4)
 163     trad_frame_set_reg_addr (this_cache, regnum, addr);
 164
 165   /* Construct the frame ID using the function start.  */
 166   trad_frame_set_id (this_cache, frame_id_build (base, func));
 167 }
 168
 169 static const struct tramp_frame m68kobsd_sigtramp = {
 170   SIGTRAMP_FRAME,
 171   2,
 172   {
 173     { 0x206f, -1 }, { 0x000c, -1},      /* moveal %sp@(12),%a0 */
 174     { 0x4e90, -1 },                     /* jsr %a0@ */
 175     { 0x588f, -1 },                     /* addql #4,%sp */
 176     { 0x4e41, -1 },                     /* trap #1 */
 177     { 0x2f40, -1 }, { 0x0004, -1 },     /* moveal %d0,%sp@(4) */
 178     { 0x7001, -1 },                     /* moveq #SYS_exit,%d0 */
 179     { 0x4e40, -1 },                     /* trap #0 */
 180     { TRAMP_SENTINEL_INSN, -1 }
 181   },
 182   m68kobsd_sigtramp_cache_init
 183 };
 184 \f
 185
 186 static void
 187 m68kbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 188 {
 189   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 190
 191   tdep->jb_pc = 5;
 192   tdep->jb_elt_size = 4;
 193
 194   set_gdbarch_decr_pc_after_break (gdbarch, 2);
 195
 196   set_gdbarch_iterate_over_regset_sections
 197     (gdbarch, m68kbsd_iterate_over_regset_sections);
 198 }
 199
 200 /* OpenBSD and NetBSD a.out.  */
 201
 202 static void
 203 m68kbsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 204 {
 205   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 206
 207   m68kbsd_init_abi (info, gdbarch);
 208
 209   tdep->struct_return = reg_struct_return;
 210
 211   tramp_frame_prepend_unwinder (gdbarch, &m68kobsd_sigtramp);
 212 }
 213
 214 /* NetBSD ELF.  */
 215
 216 static void
 217 m68kbsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 218 {
 219   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 220
 221   m68kbsd_init_abi (info, gdbarch);
 222
 223   /* NetBSD ELF uses the SVR4 ABI.  */
 224   m68k_svr4_init_abi (info, gdbarch);
 225   tdep->struct_return = pcc_struct_return;
 226
 227   /* NetBSD ELF uses SVR4-style shared libraries.  */
 228   set_solib_svr4_fetch_link_map_offsets
 229     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 230 }
 231 \f
 232
 233 static enum gdb_osabi
 234 m68kbsd_aout_osabi_sniffer (bfd *abfd)
 235 {
 236   if (strcmp (bfd_get_target (abfd), "a.out-m68k-netbsd") == 0
 237       || strcmp (bfd_get_target (abfd), "a.out-m68k4k-netbsd") == 0)
 238     return GDB_OSABI_NETBSD_AOUT;
 239
 240   return GDB_OSABI_UNKNOWN;
 241 }
 242
 243 static enum gdb_osabi
 244 m68kbsd_core_osabi_sniffer (bfd *abfd)
 245 {
 246   if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
 247     return GDB_OSABI_NETBSD_AOUT;
 248
 249   return GDB_OSABI_UNKNOWN;
 250 }
 251 \f
 252
 253 /* Provide a prototype to silence -Wmissing-prototypes.  */
 254 void _initialize_m68kbsd_tdep (void);
 255
 256 void
 257 _initialize_m68kbsd_tdep (void)
 258 {
 259   gdbarch_register_osabi_sniffer (bfd_arch_m68k, bfd_target_aout_flavour,
 260                                   m68kbsd_aout_osabi_sniffer);
 261
 262   /* BFD doesn't set a flavour for NetBSD style a.out core files.  */
 263   gdbarch_register_osabi_sniffer (bfd_arch_m68k, bfd_target_unknown_flavour,
 264                                   m68kbsd_core_osabi_sniffer);
 265
 266   gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_NETBSD_AOUT,
 267                           m68kbsd_aout_init_abi);
 268   gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_NETBSD_ELF,
 269                           m68kbsd_elf_init_abi);
 270 }