gdb/i386-nto-tdep.c

   1 /* Target-dependent code for QNX Neutrino x86.
   2
   3    Copyright (C) 2003-2004, 2007-2012 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 #ifndef X86_CPU_FXSR
  38 #define X86_CPU_FXSR (1L << 12)
  39 #endif
  40
  41 /* Why 13?  Look in our /usr/include/x86/context.h header at the
  42    x86_cpu_registers structure and you'll see an 'exx' junk register
  43    that is just filler.  Don't ask me, ask the kernel guys.  */
  44 #define NUM_GPREGS 13
  45
  46 /* Mapping between the general-purpose registers in `struct xxx'
  47    format and GDB's register cache layout.  */
  48
  49 /* From <x86/context.h>.  */
  50 static int i386nto_gregset_reg_offset[] =
  51 {
  52   7 * 4,                        /* %eax */
  53   6 * 4,                        /* %ecx */
  54   5 * 4,                        /* %edx */
  55   4 * 4,                        /* %ebx */
  56   11 * 4,                       /* %esp */
  57   2 * 4,                        /* %epb */
  58   1 * 4,                        /* %esi */
  59   0 * 4,                        /* %edi */
  60   8 * 4,                        /* %eip */
  61   10 * 4,                       /* %eflags */
  62   9 * 4,                        /* %cs */
  63   12 * 4,                       /* %ss */
  64   -1                            /* filler */
  65 };
  66
  67 /* Given a GDB register number REGNUM, return the offset into
  68    Neutrino's register structure or -1 if the register is unknown.  */
  69
  70 static int
  71 nto_reg_offset (int regnum)
  72 {
  73   if (regnum >= 0 && regnum < ARRAY_SIZE (i386nto_gregset_reg_offset))
  74     return i386nto_gregset_reg_offset[regnum];
  75
  76   return -1;
  77 }
  78
  79 static void
  80 i386nto_supply_gregset (struct regcache *regcache, char *gpregs)
  81 {
  82   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  83   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  84
  85   if(tdep->gregset == NULL)
  86     tdep->gregset = regset_alloc (gdbarch, i386_supply_gregset,
  87                                   i386_collect_gregset);
  88
  89   gdb_assert (tdep->gregset_reg_offset == i386nto_gregset_reg_offset);
  90   tdep->gregset->supply_regset (tdep->gregset, regcache, -1,
  91                                 gpregs, NUM_GPREGS * 4);
  92 }
  93
  94 static void
  95 i386nto_supply_fpregset (struct regcache *regcache, char *fpregs)
  96 {
  97   if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
  98     i387_supply_fxsave (regcache, -1, fpregs);
  99   else
 100     i387_supply_fsave (regcache, -1, fpregs);
 101 }
 102
 103 static void
 104 i386nto_supply_regset (struct regcache *regcache, int regset, char *data)
 105 {
 106   switch (regset)
 107     {
 108     case NTO_REG_GENERAL:
 109       i386nto_supply_gregset (regcache, data);
 110       break;
 111     case NTO_REG_FLOAT:
 112       i386nto_supply_fpregset (regcache, data);
 113       break;
 114     }
 115 }
 116
 117 static int
 118 i386nto_regset_id (int regno)
 119 {
 120   if (regno == -1)
 121     return NTO_REG_END;
 122   else if (regno < I386_NUM_GREGS)
 123     return NTO_REG_GENERAL;
 124   else if (regno < I386_NUM_GREGS + I387_NUM_REGS)
 125     return NTO_REG_FLOAT;
 126   else if (regno < I386_SSE_NUM_REGS)
 127     return NTO_REG_FLOAT; /* We store xmm registers in fxsave_area.  */
 128
 129   return -1;                    /* Error.  */
 130 }
 131
 132 static int
 133 i386nto_register_area (struct gdbarch *gdbarch,
 134                        int regno, int regset, unsigned *off)
 135 {
 136   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 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, regno_base;
 152       /* The following are flags indicating number in our fxsave_area.  */
 153       int first_four = (regno >= I387_FCTRL_REGNUM (tdep)
 154                         && regno <= I387_FISEG_REGNUM (tdep));
 155       int second_four = (regno > I387_FISEG_REGNUM (tdep)
 156                          && regno <= I387_FOP_REGNUM (tdep));
 157       int st_reg = (regno >= I387_ST0_REGNUM (tdep)
 158                     && regno < I387_ST0_REGNUM (tdep) + 8);
 159       int xmm_reg = (regno >= I387_XMM0_REGNUM (tdep)
 160                      && regno < I387_MXCSR_REGNUM (tdep));
 161
 162       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 163         {
 164           off_adjust = 32;
 165           regsize = 16;
 166           regset_size = 512;
 167           /* fxsave_area structure.  */
 168           if (first_four)
 169             {
 170               /* fpu_control_word, fpu_status_word, fpu_tag_word, fpu_operand
 171                  registers.  */
 172               regsize = 2; /* Two bytes each.  */
 173               off_adjust = 0;
 174               regno_base = I387_FCTRL_REGNUM (tdep);
 175             }
 176           else if (second_four)
 177             {
 178               /* fpu_ip, fpu_cs, fpu_op, fpu_ds registers.  */
 179               regsize = 4;
 180               off_adjust = 8;
 181               regno_base = I387_FISEG_REGNUM (tdep) + 1;
 182             }
 183           else if (st_reg)
 184             {
 185               /* ST registers.  */
 186               regsize = 16;
 187               off_adjust = 32;
 188               regno_base = I387_ST0_REGNUM (tdep);
 189             }
 190           else if (xmm_reg)
 191             {
 192               /* XMM registers.  */
 193               regsize = 16;
 194               off_adjust = 160;
 195               regno_base = I387_XMM0_REGNUM (tdep);
 196             }
 197           else if (regno == I387_MXCSR_REGNUM (tdep))
 198             {
 199               regsize = 4;
 200               off_adjust = 24;
 201               regno_base = I387_MXCSR_REGNUM (tdep);
 202             }
 203           else
 204             {
 205               /* Whole regset.  */
 206               gdb_assert (regno == -1);
 207               off_adjust = 0;
 208               regno_base = 0;
 209               regsize = regset_size;
 210             }
 211         }
 212       else
 213         {
 214           regset_size = 108;
 215           /* fsave_area structure.  */
 216           if (first_four || second_four)
 217             {
 218               /* fpu_control_word, ... , fpu_ds registers.  */
 219               regsize = 4;
 220               off_adjust = 0;
 221               regno_base = I387_FCTRL_REGNUM (tdep);
 222             }
 223           else if (st_reg)
 224             {
 225               /* One of ST registers.  */
 226               regsize = 10;
 227               off_adjust = 7 * 4;
 228               regno_base = I387_ST0_REGNUM (tdep);
 229             }
 230           else
 231             {
 232               /* Whole regset.  */
 233               gdb_assert (regno == -1);
 234               off_adjust = 0;
 235               regno_base = 0;
 236               regsize = regset_size;
 237             }
 238         }
 239
 240       if (regno != -1)
 241         *off = off_adjust + (regno - regno_base) * regsize;
 242       else
 243         *off = 0;
 244       return regsize;
 245     }
 246   return -1;
 247 }
 248
 249 static int
 250 i386nto_regset_fill (const struct regcache *regcache, int regset, char *data)
 251 {
 252   if (regset == NTO_REG_GENERAL)
 253     {
 254       int regno;
 255
 256       for (regno = 0; regno < NUM_GPREGS; regno++)
 257         {
 258           int offset = nto_reg_offset (regno);
 259           if (offset != -1)
 260             regcache_raw_collect (regcache, regno, data + offset);
 261         }
 262     }
 263   else if (regset == NTO_REG_FLOAT)
 264     {
 265       if (nto_cpuinfo_valid && nto_cpuinfo_flags | X86_CPU_FXSR)
 266         i387_collect_fxsave (regcache, -1, data);
 267       else
 268         i387_collect_fsave (regcache, -1, data);
 269     }
 270   else
 271     return -1;
 272
 273   return 0;
 274 }
 275
 276 /* Return whether THIS_FRAME corresponds to a QNX Neutrino sigtramp
 277    routine.  */
 278
 279 static int
 280 i386nto_sigtramp_p (struct frame_info *this_frame)
 281 {
 282   CORE_ADDR pc = get_frame_pc (this_frame);
 283   const char *name;
 284
 285   find_pc_partial_function (pc, &name, NULL, NULL);
 286   return name && strcmp ("__signalstub", name) == 0;
 287 }
 288
 289 /* Assuming THIS_FRAME is a QNX Neutrino sigtramp routine, return the
 290    address of the associated sigcontext structure.  */
 291
 292 static CORE_ADDR
 293 i386nto_sigcontext_addr (struct frame_info *this_frame)
 294 {
 295   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 296   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 297   char buf[4];
 298   CORE_ADDR ptrctx;
 299
 300   /* We store __ucontext_t addr in EDI register.  */
 301   get_frame_register (this_frame, I386_EDI_REGNUM, buf);
 302   ptrctx = extract_unsigned_integer (buf, 4, byte_order);
 303   ptrctx += 24 /* Context pointer is at this offset.  */;
 304
 305   return ptrctx;
 306 }
 307
 308 static void
 309 init_i386nto_ops (void)
 310 {
 311   nto_regset_id = i386nto_regset_id;
 312   nto_supply_gregset = i386nto_supply_gregset;
 313   nto_supply_fpregset = i386nto_supply_fpregset;
 314   nto_supply_altregset = nto_dummy_supply_regset;
 315   nto_supply_regset = i386nto_supply_regset;
 316   nto_register_area = i386nto_register_area;
 317   nto_regset_fill = i386nto_regset_fill;
 318   nto_fetch_link_map_offsets =
 319     svr4_ilp32_fetch_link_map_offsets;
 320 }
 321
 322 static void
 323 i386nto_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 324 {
 325   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 326   static struct target_so_ops nto_svr4_so_ops;
 327
 328   /* Deal with our strange signals.  */
 329   nto_initialize_signals ();
 330
 331   /* NTO uses ELF.  */
 332   i386_elf_init_abi (info, gdbarch);
 333
 334   /* Neutrino rewinds to look more normal.  Need to override the i386
 335      default which is [unfortunately] to decrement the PC.  */
 336   set_gdbarch_decr_pc_after_break (gdbarch, 0);
 337
 338   tdep->gregset_reg_offset = i386nto_gregset_reg_offset;
 339   tdep->gregset_num_regs = ARRAY_SIZE (i386nto_gregset_reg_offset);
 340   tdep->sizeof_gregset = NUM_GPREGS * 4;
 341
 342   tdep->sigtramp_p = i386nto_sigtramp_p;
 343   tdep->sigcontext_addr = i386nto_sigcontext_addr;
 344   tdep->sc_reg_offset = i386nto_gregset_reg_offset;
 345   tdep->sc_num_regs = ARRAY_SIZE (i386nto_gregset_reg_offset);
 346
 347   /* Setjmp()'s return PC saved in EDX (5).  */
 348   tdep->jb_pc_offset = 20;      /* 5x32 bit ints in.  */
 349
 350   set_solib_svr4_fetch_link_map_offsets
 351     (gdbarch, svr4_ilp32_fetch_link_map_offsets);
 352
 353   /* Initialize this lazily, to avoid an initialization order
 354      dependency on solib-svr4.c's _initialize routine.  */
 355   if (nto_svr4_so_ops.in_dynsym_resolve_code == NULL)
 356     {
 357       nto_svr4_so_ops = svr4_so_ops;
 358
 359       /* Our loader handles solib relocations differently than svr4.  */
 360       nto_svr4_so_ops.relocate_section_addresses
 361         = nto_relocate_section_addresses;
 362
 363       /* Supply a nice function to find our solibs.  */
 364       nto_svr4_so_ops.find_and_open_solib
 365         = nto_find_and_open_solib;
 366
 367       /* Our linker code is in libc.  */
 368       nto_svr4_so_ops.in_dynsym_resolve_code
 369         = nto_in_dynsym_resolve_code;
 370     }
 371   set_solib_ops (gdbarch, &nto_svr4_so_ops);
 372 }
 373
 374 /* Provide a prototype to silence -Wmissing-prototypes.  */
 375 extern initialize_file_ftype _initialize_i386nto_tdep;
 376
 377 void
 378 _initialize_i386nto_tdep (void)
 379 {
 380   init_i386nto_ops ();
 381   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_QNXNTO,
 382                           i386nto_init_abi);
 383   gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_elf_flavour,
 384                                   nto_elf_osabi_sniffer);
 385 }