gdb/i386-nto-tdep.c

   1 /* Target-dependent code for QNX Neutrino x86.
   2
   3    Copyright (C) 2003, 2004, 2007, 2008 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 3 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, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "frame.h"
  24 #include "osabi.h"
  25 #include "regcache.h"
  26 #include "target.h"
  27
  28 #include "gdb_assert.h"
  29 #include "gdb_string.h"
  30
  31 #include "i386-tdep.h"
  32 #include "i387-tdep.h"
  33 #include "nto-tdep.h"
  34 #include "solib.h"
  35 #include "solib-svr4.h"
  36
  37 /* Target vector for QNX NTO x86.  */
  38 static struct nto_target_ops i386_nto_target;
  39
  40 #ifndef X86_CPU_FXSR
  41 #define X86_CPU_FXSR (1L << 12)
  42 #endif
  43
  44 /* Why 13?  Look in our /usr/include/x86/context.h header at the
  45    x86_cpu_registers structure and you'll see an 'exx' junk register
  46    that is just filler.  Don't ask me, ask the kernel guys.  */
  47 #define NUM_GPREGS 13
  48
  49 /* Mapping between the general-purpose registers in `struct xxx'
  50    format and GDB's register cache layout.  */
  51
  52 /* From <x86/context.h>.  */
  53 static int i386nto_gregset_reg_offset[] =
  54 {
  55   7 * 4,                        /* %eax */
  56   6 * 4,                        /* %ecx */
  57   5 * 4,                        /* %edx */
  58   4 * 4,                        /* %ebx */
  59   11 * 4,                       /* %esp */
  60   2 * 4,                        /* %epb */
  61   1 * 4,                        /* %esi */
  62   0 * 4,                        /* %edi */
  63   8 * 4,                        /* %eip */
  64   10 * 4,                       /* %eflags */
  65   9 * 4,                        /* %cs */
  66   12 * 4,                       /* %ss */
  67   -1                            /* filler */
  68 };
  69
  70 /* Given a GDB register number REGNUM, return the offset into
  71    Neutrino's register structure or -1 if the register is unknown.  */
  72
  73 static int
  74 nto_reg_offset (int regnum)
  75 {
  76   if (regnum >= 0 && regnum < ARRAY_SIZE (i386nto_gregset_reg_offset))
  77     return i386nto_gregset_reg_offset[regnum];
  78
  79   return -1;
  80 }
  81
  82 static void
  83 i386nto_supply_gregset (struct regcache *regcache, char *gpregs)
  84 {
  85   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  86   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  87
  88   if(tdep->gregset == NULL)
  89     tdep->gregset = regset_alloc (gdbarch, i386_supply_gregset,
  90                                   i386_collect_gregset);
  91
  92   gdb_assert (tdep->gregset_reg_offset == i386nto_gregset_reg_offset);
  93   tdep->gregset->supply_regset (tdep->gregset, regcache, -1,
  94                                 gpregs, NUM_GPREGS * 4);
  95 }
  96
  97 static void
  98 i386nto_supply_fpregset (struct regcache *regcache, char *fpregs)
  99 {
 100   if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 101     i387_supply_fxsave (regcache, -1, fpregs);
 102   else
 103     i387_supply_fsave (regcache, -1, fpregs);
 104 }
 105
 106 static void
 107 i386nto_supply_regset (struct regcache *regcache, int regset, char *data)
 108 {
 109   switch (regset)
 110     {
 111     case NTO_REG_GENERAL:
 112       i386nto_supply_gregset (regcache, data);
 113       break;
 114     case NTO_REG_FLOAT:
 115       i386nto_supply_fpregset (regcache, data);
 116       break;
 117     }
 118 }
 119
 120 static int
 121 i386nto_regset_id (int regno)
 122 {
 123   if (regno == -1)
 124     return NTO_REG_END;
 125   else if (regno < I386_NUM_GREGS)
 126     return NTO_REG_GENERAL;
 127   else if (regno < I386_NUM_GREGS + I386_NUM_FREGS)
 128     return NTO_REG_FLOAT;
 129
 130   return -1;                    /* Error.  */
 131 }
 132
 133 static int
 134 i386nto_register_area (int regno, int regset, unsigned *off)
 135 {
 136   int len;
 137
 138   *off = 0;
 139   if (regset == NTO_REG_GENERAL)
 140     {
 141       if (regno == -1)
 142         return NUM_GPREGS * 4;
 143
 144       *off = nto_reg_offset (regno);
 145       if (*off == -1)
 146         return 0;
 147       return 4;
 148     }
 149   else if (regset == NTO_REG_FLOAT)
 150     {
 151       unsigned off_adjust, regsize, regset_size;
 152
 153       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 154         {
 155           off_adjust = 32;
 156           regsize = 16;
 157           regset_size = 512;
 158         }
 159       else
 160         {
 161           off_adjust = 28;
 162           regsize = 10;
 163           regset_size = 128;
 164         }
 165
 166       if (regno == -1)
 167         return regset_size;
 168
 169       *off = (regno - gdbarch_fp0_regnum (current_gdbarch))
 170              * regsize + off_adjust;
 171       return 10;
 172       /* Why 10 instead of regsize?  GDB only stores 10 bytes per FP
 173          register so if we're sending a register back to the target,
 174          we only want pdebug to write 10 bytes so as not to clobber
 175          the reserved 6 bytes in the fxsave structure.  */
 176     }
 177   return -1;
 178 }
 179
 180 static int
 181 i386nto_regset_fill (const struct regcache *regcache, int regset, char *data)
 182 {
 183   if (regset == NTO_REG_GENERAL)
 184     {
 185       int regno;
 186
 187       for (regno = 0; regno < NUM_GPREGS; regno++)
 188         {
 189           int offset = nto_reg_offset (regno);
 190           if (offset != -1)
 191             regcache_raw_collect (regcache, regno, data + offset);
 192         }
 193     }
 194   else if (regset == NTO_REG_FLOAT)
 195     {
 196       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 197         i387_collect_fxsave (regcache, -1, data);
 198       else
 199         i387_collect_fsave (regcache, -1, data);
 200     }
 201   else
 202     return -1;
 203
 204   return 0;
 205 }
 206
 207 /* Return whether the frame preceding NEXT_FRAME corresponds to a QNX
 208    Neutrino sigtramp routine.  */
 209
 210 static int
 211 i386nto_sigtramp_p (struct frame_info *next_frame)
 212 {
 213   CORE_ADDR pc = frame_pc_unwind (next_frame);
 214   char *name;
 215
 216   find_pc_partial_function (pc, &name, NULL, NULL);
 217   return name && strcmp ("__signalstub", name) == 0;
 218 }
 219
 220 #define I386_NTO_SIGCONTEXT_OFFSET 136
 221
 222 /* Assuming NEXT_FRAME is a frame following a QNX Neutrino sigtramp
 223    routine, return the address of the associated sigcontext structure.  */
 224
 225 static CORE_ADDR
 226 i386nto_sigcontext_addr (struct frame_info *next_frame)
 227 {
 228   char buf[4];
 229   CORE_ADDR sp;
 230
 231   frame_unwind_register (next_frame, I386_ESP_REGNUM, buf);
 232   sp = extract_unsigned_integer (buf, 4);
 233
 234   return sp + I386_NTO_SIGCONTEXT_OFFSET;
 235 }
 236
 237 static void
 238 init_i386nto_ops (void)
 239 {
 240   i386_nto_target.regset_id = i386nto_regset_id;
 241   i386_nto_target.supply_gregset = i386nto_supply_gregset;
 242   i386_nto_target.supply_fpregset = i386nto_supply_fpregset;
 243   i386_nto_target.supply_altregset = nto_dummy_supply_regset;
 244   i386_nto_target.supply_regset = i386nto_supply_regset;
 245   i386_nto_target.register_area = i386nto_register_area;
 246   i386_nto_target.regset_fill = i386nto_regset_fill;
 247   i386_nto_target.fetch_link_map_offsets =
 248     svr4_ilp32_fetch_link_map_offsets;
 249 }
 250
 251 static void
 252 i386nto_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 253 {
 254   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 255   static struct target_so_ops nto_svr4_so_ops;
 256
 257   /* Deal with our strange signals.  */
 258   nto_initialize_signals ();
 259
 260   /* NTO uses ELF.  */
 261   i386_elf_init_abi (info, gdbarch);
 262
 263   /* Neutrino rewinds to look more normal.  Need to override the i386
 264      default which is [unfortunately] to decrement the PC.  */
 265   set_gdbarch_decr_pc_after_break (gdbarch, 0);
 266
 267   tdep->gregset_reg_offset = i386nto_gregset_reg_offset;
 268   tdep->gregset_num_regs = ARRAY_SIZE (i386nto_gregset_reg_offset);
 269   tdep->sizeof_gregset = NUM_GPREGS * 4;
 270
 271   tdep->sigtramp_p = i386nto_sigtramp_p;
 272   tdep->sigcontext_addr = i386nto_sigcontext_addr;
 273   tdep->sc_pc_offset = 56;
 274   tdep->sc_sp_offset = 68;
 275
 276   /* Setjmp()'s return PC saved in EDX (5).  */
 277   tdep->jb_pc_offset = 20;      /* 5x32 bit ints in.  */
 278
 279   set_solib_svr4_fetch_link_map_offsets
 280     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 281
 282   /* Initialize this lazily, to avoid an initialization order
 283      dependency on solib-svr4.c's _initialize routine.  */
 284   if (nto_svr4_so_ops.in_dynsym_resolve_code == NULL)
 285     {
 286       nto_svr4_so_ops = svr4_so_ops;
 287
 288       /* Our loader handles solib relocations differently than svr4.  */
 289       nto_svr4_so_ops.relocate_section_addresses
 290         = nto_relocate_section_addresses;
 291
 292       /* Supply a nice function to find our solibs.  */
 293       nto_svr4_so_ops.find_and_open_solib
 294         = nto_find_and_open_solib;
 295
 296       /* Our linker code is in libc.  */
 297       nto_svr4_so_ops.in_dynsym_resolve_code
 298         = nto_in_dynsym_resolve_code;
 299     }
 300   set_solib_ops (gdbarch, &nto_svr4_so_ops);
 301
 302   nto_set_target (&i386_nto_target);
 303 }
 304
 305 void
 306 _initialize_i386nto_tdep (void)
 307 {
 308   init_i386nto_ops ();
 309   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_QNXNTO,
 310                           i386nto_init_abi);
 311   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour,
 312                                   nto_elf_osabi_sniffer);
 313 }