gdb/i386-nto-tdep.c

   1 /* Target-dependent code for QNX Neutrino x86.
   2
   3    Copyright 2003, 2004 Free Software Foundation, Inc.
   4
   5    Contributed by QNX Software Systems Ltd.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330,
  22    Boston, MA 02111-1307, USA.  */
  23
  24 #include "defs.h"
  25 #include "frame.h"
  26 #include "osabi.h"
  27 #include "regcache.h"
  28 #include "target.h"
  29
  30 #include "gdb_assert.h"
  31 #include "gdb_string.h"
  32
  33 #include "i386-tdep.h"
  34 #include "i387-tdep.h"
  35 #include "nto-tdep.h"
  36 #include "solib-svr4.h"
  37
  38 #ifndef X86_CPU_FXSR
  39 #define X86_CPU_FXSR (1L << 12)
  40 #endif
  41
  42 /* Why 13?  Look in our /usr/include/x86/context.h header at the
  43    x86_cpu_registers structure and you'll see an 'exx' junk register
  44    that is just filler.  Don't ask me, ask the kernel guys.  */
  45 #define NUM_GPREGS 13
  46
  47 /* Map a GDB register number to an offset in the reg structure.  */
  48 static int regmap[] = {
  49   (7 * 4),                      /* eax */
  50   (6 * 4),                      /* ecx */
  51   (5 * 4),                      /* edx */
  52   (4 * 4),                      /* ebx */
  53   (11 * 4),                     /* esp */
  54   (2 * 4),                      /* epb */
  55   (1 * 4),                      /* esi */
  56   (0 * 4),                      /* edi */
  57   (8 * 4),                      /* eip */
  58   (10 * 4),                     /* eflags */
  59   (9 * 4),                      /* cs */
  60   (12 * 4),                     /* ss */
  61   (-1 * 4)                      /* filler */
  62 };
  63
  64 static struct nto_target_ops i386_nto_target;
  65
  66 /* Given a gdb regno, return the offset into Neutrino's register structure
  67    or -1 if register is unknown.  */
  68 static int
  69 nto_reg_offset (int regno)
  70 {
  71   return (regno >= 0 && regno < NUM_GPREGS) ? regmap[regno] : -1;
  72 }
  73
  74 static void
  75 i386nto_supply_gregset (char *gpregs)
  76 {
  77   unsigned regno;
  78   int empty = 0;
  79
  80   for (regno = 0; regno < I386_NUM_GREGS; regno++)
  81     {
  82       int offset = nto_reg_offset (regno);
  83       if (offset == -1)
  84         regcache_raw_supply (current_regcache, regno, (char *) &empty);
  85       else
  86         regcache_raw_supply (current_regcache, regno, gpregs + offset);
  87     }
  88 }
  89
  90 static void
  91 i386nto_supply_fpregset (char *fpregs)
  92 {
  93   if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
  94     i387_supply_fxsave (current_regcache, -1, fpregs);
  95   else
  96     i387_supply_fsave (current_regcache, -1, fpregs);
  97 }
  98
  99 static void
 100 i386nto_supply_regset (int regset, char *data)
 101 {
 102   switch (regset)
 103     {
 104     case NTO_REG_GENERAL:       /* QNX has different ordering of GP regs than GDB.  */
 105       i386nto_supply_gregset (data);
 106       break;
 107     case NTO_REG_FLOAT:
 108       i386nto_supply_fpregset (data);
 109       break;
 110     }
 111 }
 112
 113 static int
 114 i386nto_regset_id (int regno)
 115 {
 116   if (regno == -1)
 117     return NTO_REG_END;
 118   else if (regno < I386_NUM_GREGS)
 119     return NTO_REG_GENERAL;
 120   else if (regno < I386_NUM_GREGS + I386_NUM_FREGS)
 121     return NTO_REG_FLOAT;
 122
 123   return -1;                    /* Error.  */
 124 }
 125
 126 static int
 127 i386nto_register_area (int regno, int regset, unsigned *off)
 128 {
 129   int len;
 130
 131   *off = 0;
 132   if (regset == NTO_REG_GENERAL)
 133     {
 134       if (regno == -1)
 135         return NUM_GPREGS * 4;
 136
 137       *off = nto_reg_offset (regno);
 138       if (*off == -1)
 139         return 0;
 140       return 4;
 141     }
 142   else if (regset == NTO_REG_FLOAT)
 143     {
 144       unsigned off_adjust, regsize, regset_size;
 145
 146       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 147         {
 148           off_adjust = 32;
 149           regsize = 16;
 150           regset_size = 512;
 151         }
 152       else
 153         {
 154           off_adjust = 28;
 155           regsize = 10;
 156           regset_size = 128;
 157         }
 158
 159       if (regno == -1)
 160         return regset_size;
 161
 162       *off = (regno - FP0_REGNUM) * regsize + off_adjust;
 163       return 10;
 164       /* Why 10 instead of regsize?  GDB only stores 10 bytes per FP
 165          register so if we're sending a register back to the target,
 166          we only want pdebug to write 10 bytes so as not to clobber
 167          the reserved 6 bytes in the fxsave structure.  */
 168     }
 169   return -1;
 170 }
 171
 172 static int
 173 i386nto_regset_fill (int regset, char *data)
 174 {
 175   if (regset == NTO_REG_GENERAL)
 176     {
 177       int regno;
 178
 179       for (regno = 0; regno < NUM_GPREGS; regno++)
 180         {
 181           int offset = nto_reg_offset (regno);
 182           if (offset != -1)
 183             regcache_raw_collect (current_regcache, regno, data + offset);
 184         }
 185     }
 186   else if (regset == NTO_REG_FLOAT)
 187     {
 188       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 189         i387_fill_fxsave (data, -1);
 190       else
 191         i387_fill_fsave (data, -1);
 192     }
 193   else
 194     return -1;
 195
 196   return 0;
 197 }
 198
 199 /* Return whether the frame preceding NEXT_FRAME corresponds to a QNX
 200    Neutrino sigtramp routine.  */
 201
 202 static int
 203 i386nto_sigtramp_p (struct frame_info *next_frame)
 204 {
 205   CORE_ADDR pc = frame_pc_unwind (next_frame);
 206   char *name;
 207
 208   find_pc_partial_function (pc, &name, NULL, NULL);
 209   return name && strcmp ("__signalstub", name) == 0;
 210 }
 211
 212 #define I386_NTO_SIGCONTEXT_OFFSET 136
 213
 214 /* Assuming NEXT_FRAME is a frame following a QNX Neutrino sigtramp
 215    routine, return the address of the associated sigcontext structure.  */
 216
 217 static CORE_ADDR
 218 i386nto_sigcontext_addr (struct frame_info *next_frame)
 219 {
 220   char buf[4];
 221   CORE_ADDR sp;
 222
 223   frame_unwind_register (next_frame, I386_ESP_REGNUM, buf);
 224   sp = extract_unsigned_integer (buf, 4);
 225
 226   return sp + I386_NTO_SIGCONTEXT_OFFSET;
 227 }
 228
 229 static void
 230 init_i386nto_ops (void)
 231 {
 232   i386_nto_target.regset_id = i386nto_regset_id;
 233   i386_nto_target.supply_gregset = i386nto_supply_gregset;
 234   i386_nto_target.supply_fpregset = i386nto_supply_fpregset;
 235   i386_nto_target.supply_altregset = nto_dummy_supply_regset;
 236   i386_nto_target.supply_regset = i386nto_supply_regset;
 237   i386_nto_target.register_area = i386nto_register_area;
 238   i386_nto_target.regset_fill = i386nto_regset_fill;
 239   i386_nto_target.fetch_link_map_offsets =
 240     svr4_ilp32_fetch_link_map_offsets;
 241 }
 242
 243 static void
 244 i386nto_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 245 {
 246   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 247
 248   /* Deal with our strange signals.  */
 249   nto_initialize_signals ();
 250
 251   /* NTO uses ELF.  */
 252   i386_elf_init_abi (info, gdbarch);
 253
 254   /* Neutrino rewinds to look more normal.  Need to override the i386
 255      default which is [unfortunately] to decrement the PC.  */
 256   set_gdbarch_decr_pc_after_break (gdbarch, 0);
 257
 258   /* NTO has shared libraries.  */
 259   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 260
 261   tdep->sigtramp_p = i386nto_sigtramp_p;
 262   tdep->sigcontext_addr = i386nto_sigcontext_addr;
 263   tdep->sc_pc_offset = 56;
 264   tdep->sc_sp_offset = 68;
 265
 266   /* Setjmp()'s return PC saved in EDX (5).  */
 267   tdep->jb_pc_offset = 20;      /* 5x32 bit ints in.  */
 268
 269   set_solib_svr4_fetch_link_map_offsets
 270     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 271
 272   /* Our loader handles solib relocations slightly differently than svr4.  */
 273   TARGET_SO_RELOCATE_SECTION_ADDRESSES = nto_relocate_section_addresses;
 274
 275   /* Supply a nice function to find our solibs.  */
 276   TARGET_SO_FIND_AND_OPEN_SOLIB = nto_find_and_open_solib;
 277
 278   /* Our linker code is in libc.  */
 279   TARGET_SO_IN_DYNSYM_RESOLVE_CODE = nto_in_dynsym_resolve_code;
 280
 281   nto_set_target (&i386_nto_target);
 282 }
 283
 284 void
 285 _initialize_i386nto_tdep (void)
 286 {
 287   init_i386nto_ops ();
 288   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_QNXNTO,
 289                           i386nto_init_abi);
 290   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour,
 291                                   nto_elf_osabi_sniffer);
 292 }