gdb/i386-nto-tdep.c

   1 /* i386-nto-tdep.c - i386 specific functionality for QNX Neutrino.
   2
   3    Copyright 2003 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 "gdb_string.h"
  25 #include "gdb_assert.h"
  26 #include "defs.h"
  27 #include "frame.h"
  28 #include "target.h"
  29 #include "regcache.h"
  30 #include "solib-svr4.h"
  31 #include "i386-tdep.h"
  32 #include "nto-tdep.h"
  33 #include "osabi.h"
  34 #include "i387-tdep.h"
  35
  36 #ifndef X86_CPU_FXSR
  37 #define X86_CPU_FXSR (1L << 12)
  38 #endif
  39
  40 /* Why 13?  Look in our /usr/include/x86/context.h header at the
  41    x86_cpu_registers structure and you'll see an 'exx' junk register
  42    that is just filler.  Don't ask me, ask the kernel guys.  */
  43 #define NUM_GPREGS 13
  44
  45 /* Map a GDB register number to an offset in the reg structure.  */
  46 static int regmap[] = {
  47   (7 * 4),                      /* eax */
  48   (6 * 4),                      /* ecx */
  49   (5 * 4),                      /* edx */
  50   (4 * 4),                      /* ebx */
  51   (11 * 4),                     /* esp */
  52   (2 * 4),                      /* epb */
  53   (1 * 4),                      /* esi */
  54   (0 * 4),                      /* edi */
  55   (8 * 4),                      /* eip */
  56   (10 * 4),                     /* eflags */
  57   (9 * 4),                      /* cs */
  58   (12 * 4),                     /* ss */
  59   (-1 * 4)                      /* filler */
  60 };
  61
  62 /* Given a gdb regno, return the offset into Neutrino's register structure
  63    or -1 if register is unknown.  */
  64 static int
  65 nto_reg_offset (int regno)
  66 {
  67   return (regno >= 0 && regno < NUM_GPREGS) ? regmap[regno] : -1;
  68 }
  69
  70 static void
  71 i386nto_supply_gregset (char *gpregs)
  72 {
  73   unsigned regno;
  74   int empty = 0;
  75
  76   for (regno = 0; regno < FP0_REGNUM; regno++)
  77     {
  78       int offset = nto_reg_offset (regno);
  79       if (offset == -1)
  80         supply_register (regno, (char *) &empty);
  81       else
  82         supply_register (regno, gpregs + offset);
  83     }
  84 }
  85
  86 static void
  87 i386nto_supply_fpregset (char *fpregs)
  88 {
  89   if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
  90     i387_supply_fxsave (current_regcache, -1, fpregs);
  91   else
  92     i387_supply_fsave (current_regcache, -1, fpregs);
  93 }
  94
  95 static void
  96 i386nto_supply_regset (int regset, char *data)
  97 {
  98   switch (regset)
  99     {
 100     case NTO_REG_GENERAL:       /* QNX has different ordering of GP regs than GDB.  */
 101       i386nto_supply_gregset (data);
 102       break;
 103     case NTO_REG_FLOAT:
 104       i386nto_supply_fpregset (data);
 105       break;
 106     }
 107 }
 108
 109 static int
 110 i386nto_regset_id (int regno)
 111 {
 112   if (regno == -1)
 113     return NTO_REG_END;
 114   else if (regno < FP0_REGNUM)
 115     return NTO_REG_GENERAL;
 116   else if (regno < FPC_REGNUM)
 117     return NTO_REG_FLOAT;
 118
 119   return -1;                    /* Error.  */
 120 }
 121
 122 static int
 123 i386nto_register_area (int regno, int regset, unsigned *off)
 124 {
 125   int len;
 126
 127   *off = 0;
 128   if (regset == NTO_REG_GENERAL)
 129     {
 130       if (regno == -1)
 131         return NUM_GPREGS * 4;
 132
 133       *off = nto_reg_offset (regno);
 134       if (*off == -1)
 135         return 0;
 136       return 4;
 137     }
 138   else if (regset == NTO_REG_FLOAT)
 139     {
 140       unsigned off_adjust, regsize, regset_size;
 141
 142       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 143         {
 144           off_adjust = 32;
 145           regsize = 16;
 146           regset_size = 512;
 147         }
 148       else
 149         {
 150           off_adjust = 28;
 151           regsize = 10;
 152           regset_size = 128;
 153         }
 154
 155       if (regno == -1)
 156         return regset_size;
 157
 158       *off = (regno - FP0_REGNUM) * regsize + off_adjust;
 159       return 10;
 160       /* Why 10 instead of regsize?  GDB only stores 10 bytes per FP
 161          register so if we're sending a register back to the target,
 162          we only want pdebug to write 10 bytes so as not to clobber
 163          the reserved 6 bytes in the fxsave structure.  */
 164     }
 165   return -1;
 166 }
 167
 168 static int
 169 i386nto_regset_fill (int regset, char *data)
 170 {
 171   if (regset == NTO_REG_GENERAL)
 172     {
 173       int regno;
 174
 175       for (regno = 0; regno < NUM_GPREGS; regno++)
 176         {
 177           int offset = nto_reg_offset (regno);
 178           if (offset != -1)
 179             regcache_collect (regno, data + offset);
 180         }
 181     }
 182   else if (regset == NTO_REG_FLOAT)
 183     {
 184       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 185         i387_fill_fxsave (data, -1);
 186       else
 187         i387_fill_fsave (data, -1);
 188     }
 189   else
 190     return -1;
 191
 192   return 0;
 193 }
 194
 195 static struct link_map_offsets *
 196 i386nto_svr4_fetch_link_map_offsets (void)
 197 {
 198   static struct link_map_offsets lmo;
 199   static struct link_map_offsets *lmp = NULL;
 200
 201   if (lmp == NULL)
 202     {
 203       lmp = &lmo;
 204
 205       lmo.r_debug_size = 8;     /* The actual size is 20 bytes, but
 206                                    only 8 bytes are used.  */
 207       lmo.r_map_offset = 4;
 208       lmo.r_map_size = 4;
 209
 210       lmo.link_map_size = 20;   /* The actual size is 552 bytes, but
 211                                    only 20 bytes are used.  */
 212       lmo.l_addr_offset = 0;
 213       lmo.l_addr_size = 4;
 214
 215       lmo.l_name_offset = 4;
 216       lmo.l_name_size = 4;
 217
 218       lmo.l_next_offset = 12;
 219       lmo.l_next_size = 4;
 220
 221       lmo.l_prev_offset = 16;
 222       lmo.l_prev_size = 4;
 223     }
 224
 225   return lmp;
 226 }
 227
 228 static int
 229 i386nto_pc_in_sigtramp (CORE_ADDR pc, char *name)
 230 {
 231   return name && strcmp ("__signalstub", name) == 0;
 232 }
 233
 234 #define I386_NTO_SIGCONTEXT_OFFSET 136
 235
 236 /* Assuming NEXT_FRAME is a frame following a QNX Neutrino sigtramp
 237    routine, return the address of the associated sigcontext structure.  */
 238
 239 static CORE_ADDR
 240 i386nto_sigcontext_addr (struct frame_info *next_frame)
 241 {
 242   char buf[4];
 243   CORE_ADDR sp;
 244
 245   frame_unwind_register (next_frame, SP_REGNUM, buf);
 246   sp = extract_unsigned_integer (buf, 4);
 247
 248   return sp + I386_NTO_SIGCONTEXT_OFFSET;
 249 }
 250
 251 static void
 252 init_i386nto_ops (void)
 253 {
 254   current_nto_target.nto_regset_id = i386nto_regset_id;
 255   current_nto_target.nto_supply_gregset = i386nto_supply_gregset;
 256   current_nto_target.nto_supply_fpregset = i386nto_supply_fpregset;
 257   current_nto_target.nto_supply_altregset = nto_dummy_supply_regset;
 258   current_nto_target.nto_supply_regset = i386nto_supply_regset;
 259   current_nto_target.nto_register_area = i386nto_register_area;
 260   current_nto_target.nto_regset_fill = i386nto_regset_fill;
 261   current_nto_target.nto_fetch_link_map_offsets =
 262     i386nto_svr4_fetch_link_map_offsets;
 263 }
 264
 265 static void
 266 i386nto_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 267 {
 268   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 269
 270   /* NTO uses ELF.  */
 271   i386_elf_init_abi (info, gdbarch);
 272
 273   /* Neutrino rewinds to look more normal.  Need to override the i386
 274      default which is [unfortunately] to decrement the PC.  */
 275   set_gdbarch_decr_pc_after_break (gdbarch, 0);
 276
 277   /* NTO has shared libraries.  */
 278   set_gdbarch_in_solib_call_trampoline (gdbarch, in_plt_section);
 279   set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
 280
 281   set_gdbarch_pc_in_sigtramp (gdbarch, i386nto_pc_in_sigtramp);
 282   tdep->sigcontext_addr = i386nto_sigcontext_addr;
 283   tdep->sc_pc_offset = 56;
 284   tdep->sc_sp_offset = 68;
 285
 286   /* Setjmp()'s return PC saved in EDX (5).  */
 287   tdep->jb_pc_offset = 20;      /* 5x32 bit ints in.  */
 288
 289   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 290                                          i386nto_svr4_fetch_link_map_offsets);
 291
 292   /* Our loader handles solib relocations slightly differently than svr4.  */
 293   TARGET_SO_RELOCATE_SECTION_ADDRESSES = nto_relocate_section_addresses;
 294
 295   /* Supply a nice function to find our solibs.  */
 296   TARGET_SO_FIND_AND_OPEN_SOLIB = nto_find_and_open_solib;
 297
 298   init_i386nto_ops ();
 299 }
 300
 301 void
 302 _initialize_i386nto_tdep (void)
 303 {
 304   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_QNXNTO,
 305                           i386nto_init_abi);
 306 }