gdb/alphanbsd-tdep.c

   1 /* Target-dependent code for NetBSD/Alpha.
   2
   3    Copyright 2002, 2003, 2004 Free Software Foundation, Inc.
   4    Contributed by Wasabi Systems, 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 "frame.h"
  26 #include "regcache.h"
  27 #include "value.h"
  28 #include "osabi.h"
  29
  30 #include "gdb_string.h"
  31
  32 #include "alpha-tdep.h"
  33 #include "alphabsd-tdep.h"
  34 #include "nbsd-tdep.h"
  35 #include "solib-svr4.h"
  36
  37 static void
  38 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which,
  39                       CORE_ADDR ignore)
  40 {
  41   char *regs, *fpregs;
  42   int regno;
  43
  44   /* Table to map a gdb register number to a trapframe register index.  */
  45   static const int regmap[] =
  46   {
  47      0,   1,   2,   3,
  48      4,   5,   6,   7,
  49      8,   9,  10,  11,
  50     12,  13,  14,  15,
  51     30,  31,  32,  16,
  52     17,  18,  19,  20,
  53     21,  22,  23,  24,
  54     25,  29,  26
  55   };
  56 #define SIZEOF_TRAPFRAME (33 * 8)
  57
  58   /* We get everything from one section.  */
  59   if (which != 0)
  60     return;
  61
  62   regs = core_reg_sect;
  63   fpregs = core_reg_sect + SIZEOF_TRAPFRAME;
  64
  65   if (core_reg_size < (SIZEOF_TRAPFRAME + SIZEOF_STRUCT_FPREG))
  66     {
  67       warning ("Wrong size register set in core file.");
  68       return;
  69     }
  70
  71   /* Integer registers.  */
  72   for (regno = 0; regno < ALPHA_ZERO_REGNUM; regno++)
  73     regcache_raw_supply (current_regcache, regno, regs + (regmap[regno] * 8));
  74   regcache_raw_supply (current_regcache, ALPHA_ZERO_REGNUM, NULL);
  75   regcache_raw_supply (current_regcache, PC_REGNUM, regs + (28 * 8));
  76
  77   /* Floating point registers.  */
  78   alphabsd_supply_fpreg (fpregs, -1);
  79 }
  80
  81 static void
  82 fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size, int which,
  83                          CORE_ADDR ignore)
  84 {
  85   switch (which)
  86     {
  87     case 0:  /* Integer registers.  */
  88       if (core_reg_size != SIZEOF_STRUCT_REG)
  89         warning ("Wrong size register set in core file.");
  90       else
  91         alphabsd_supply_reg (core_reg_sect, -1);
  92       break;
  93
  94     case 2:  /* Floating point registers.  */
  95       if (core_reg_size != SIZEOF_STRUCT_FPREG)
  96         warning ("Wrong size FP register set in core file.");
  97       else
  98         alphabsd_supply_fpreg (core_reg_sect, -1);
  99       break;
 100
 101     default:
 102       /* Don't know what kind of register request this is; just ignore it.  */
 103       break;
 104     }
 105 }
 106
 107 static struct core_fns alphanbsd_core_fns =
 108 {
 109   bfd_target_unknown_flavour,           /* core_flavour */
 110   default_check_format,                 /* check_format */
 111   default_core_sniffer,                 /* core_sniffer */
 112   fetch_core_registers,                 /* core_read_registers */
 113   NULL                                  /* next */
 114 };
 115
 116 static struct core_fns alphanbsd_elfcore_fns =
 117 {
 118   bfd_target_elf_flavour,               /* core_flavour */
 119   default_check_format,                 /* check_format */
 120   default_core_sniffer,                 /* core_sniffer */
 121   fetch_elfcore_registers,              /* core_read_registers */
 122   NULL                                  /* next */
 123 };
 124
 125 /* Under NetBSD/alpha, signal handler invocations can be identified by the
 126    designated code sequence that is used to return from a signal handler.
 127    In particular, the return address of a signal handler points to the
 128    following code sequence:
 129
 130         ldq     a0, 0(sp)
 131         lda     sp, 16(sp)
 132         lda     v0, 295(zero)   # __sigreturn14
 133         call_pal callsys
 134
 135    Each instruction has a unique encoding, so we simply attempt to match
 136    the instruction the PC is pointing to with any of the above instructions.
 137    If there is a hit, we know the offset to the start of the designated
 138    sequence and can then check whether we really are executing in the
 139    signal trampoline.  If not, -1 is returned, otherwise the offset from the
 140    start of the return sequence is returned.  */
 141 static const unsigned char sigtramp_retcode[] =
 142 {
 143   0x00, 0x00, 0x1e, 0xa6,       /* ldq a0, 0(sp) */
 144   0x10, 0x00, 0xde, 0x23,       /* lda sp, 16(sp) */
 145   0x27, 0x01, 0x1f, 0x20,       /* lda v0, 295(zero) */
 146   0x83, 0x00, 0x00, 0x00,       /* call_pal callsys */
 147 };
 148 #define RETCODE_NWORDS          4
 149 #define RETCODE_SIZE            (RETCODE_NWORDS * 4)
 150
 151 LONGEST
 152 alphanbsd_sigtramp_offset (CORE_ADDR pc)
 153 {
 154   unsigned char ret[RETCODE_SIZE], w[4];
 155   LONGEST off;
 156   int i;
 157
 158   if (deprecated_read_memory_nobpt (pc, (char *) w, 4) != 0)
 159     return -1;
 160
 161   for (i = 0; i < RETCODE_NWORDS; i++)
 162     {
 163       if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0)
 164         break;
 165     }
 166   if (i == RETCODE_NWORDS)
 167     return (-1);
 168
 169   off = i * 4;
 170   pc -= off;
 171
 172   if (deprecated_read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0)
 173     return -1;
 174
 175   if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0)
 176     return off;
 177
 178   return -1;
 179 }
 180
 181 static int
 182 alphanbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name)
 183 {
 184   return (nbsd_pc_in_sigtramp (pc, func_name)
 185           || alphanbsd_sigtramp_offset (pc) >= 0);
 186 }
 187
 188 static CORE_ADDR
 189 alphanbsd_sigcontext_addr (struct frame_info *frame)
 190 {
 191   /* FIXME: This is not correct for all versions of NetBSD/alpha.
 192      We will probably need to disassemble the trampoline to figure
 193      out which trampoline frame type we have.  */
 194   return get_frame_base (frame);
 195 }
 196
 197 static void
 198 alphanbsd_init_abi (struct gdbarch_info info,
 199                     struct gdbarch *gdbarch)
 200 {
 201   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 202
 203   /* Hook into the DWARF CFI frame unwinder.  */
 204   alpha_dwarf2_init_abi (info, gdbarch);
 205
 206   /* Hook into the MDEBUG frame unwinder.  */
 207   alpha_mdebug_init_abi (info, gdbarch);
 208
 209   /* NetBSD/alpha does not provide single step support via ptrace(2); we
 210      must use software single-stepping.  */
 211   set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);
 212
 213   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 214                                  nbsd_lp64_solib_svr4_fetch_link_map_offsets);
 215
 216   tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;
 217   tdep->pc_in_sigtramp = alphanbsd_pc_in_sigtramp;
 218   tdep->sigcontext_addr = alphanbsd_sigcontext_addr;
 219
 220   tdep->jb_pc = 2;
 221   tdep->jb_elt_size = 8;
 222 }
 223
 224 void
 225 _initialize_alphanbsd_tdep (void)
 226 {
 227   gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_NETBSD_ELF,
 228                           alphanbsd_init_abi);
 229   gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_OPENBSD_ELF,
 230                           alphanbsd_init_abi);
 231
 232   deprecated_add_core_fns (&alphanbsd_core_fns);
 233   deprecated_add_core_fns (&alphanbsd_elfcore_fns);
 234 }