gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2    Copyright 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "inferior.h"
  23 #include "regcache.h"
  24
  25 #include "gdb_assert.h"
  26 #include <signal.h>
  27 #include <stddef.h>
  28 #include <sys/types.h>
  29 #include <sys/ptrace.h>
  30 #include <machine/reg.h>
  31 #include <machine/frame.h>
  32
  33 #ifdef HAVE_SYS_PROCFS_H
  34 #include <sys/procfs.h>
  35 #endif
  36
  37 #ifndef HAVE_GREGSET_T
  38 typedef struct reg gregset_t;
  39 #endif
  40
  41 #ifndef HAVE_FPREGSET_T
  42 typedef struct fpreg fpregset_t;
  43 #endif
  44
  45 #include "gregset.h"
  46 #include "i386-tdep.h"
  47 \f
  48
  49 /* In older BSD versions we cannot get at some of the segment
  50    registers.  FreeBSD for example didn't support the %fs and %gs
  51    registers until the 3.0 release.  We have autoconf checks for their
  52    presence, and deal gracefully with their absence.  */
  53
  54 /* Registers we shouldn't try to fetch.  */
  55 #if !defined (CANNOT_FETCH_REGISTER)
  56 #define CANNOT_FETCH_REGISTER(regno) cannot_fetch_register (regno)
  57 #endif
  58
  59 /* Registers we shouldn't try to store.  */
  60 #if !defined (CANNOT_STORE_REGISTER)
  61 #define CANNOT_STORE_REGISTER(regno) cannot_fetch_register (regno)
  62 #endif
  63
  64 /* Offset to the gregset_t location where REG is stored.  */
  65 #define REG_OFFSET(reg) offsetof (gregset_t, reg)
  66
  67 /* At reg_offset[REGNO] you'll find the offset to the gregset_t
  68    location where the GDB register REGNO is stored.  Unsupported
  69    registers are marked with `-1'.  */
  70 static int reg_offset[] =
  71 {
  72   REG_OFFSET (r_eax),
  73   REG_OFFSET (r_ecx),
  74   REG_OFFSET (r_edx),
  75   REG_OFFSET (r_ebx),
  76   REG_OFFSET (r_esp),
  77   REG_OFFSET (r_ebp),
  78   REG_OFFSET (r_esi),
  79   REG_OFFSET (r_edi),
  80   REG_OFFSET (r_eip),
  81   REG_OFFSET (r_eflags),
  82   REG_OFFSET (r_cs),
  83   REG_OFFSET (r_ss),
  84   REG_OFFSET (r_ds),
  85   REG_OFFSET (r_es),
  86 #ifdef HAVE_STRUCT_REG_R_FS
  87   REG_OFFSET (r_fs),
  88 #else
  89   -1,
  90 #endif
  91 #ifdef HAVE_STRUCT_REG_R_GS
  92   REG_OFFSET (r_gs)
  93 #else
  94   -1
  95 #endif
  96 };
  97
  98 #define REG_ADDR(regset, regno) ((char *) (regset) + reg_offset[regno])
  99
 100 /* Macro to determine if a register is fetched with PT_GETREGS.  */
 101 #define GETREGS_SUPPLIES(regno) \
 102   ((0 <= (regno) && (regno) <= 15))
 103
 104 #ifdef HAVE_PT_GETXMMREGS
 105 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
 106    so that we try PT_GETXMMREGS the first time around.  */
 107 static int have_ptrace_xmmregs = -1;
 108 #endif
 109
 110 /* Return nonzero if we shouldn't try to fetch register REGNO.  */
 111
 112 static int
 113 cannot_fetch_register (int regno)
 114 {
 115   return (reg_offset[regno] == -1);
 116 }
 117 \f
 118
 119 /* Transfering the registers between GDB, inferiors and core files.  */
 120
 121 /* Fill GDB's register array with the general-purpose register values
 122    in *GREGSETP.  */
 123
 124 void
 125 supply_gregset (gregset_t *gregsetp)
 126 {
 127   int i;
 128
 129   for (i = 0; i < I386_NUM_GREGS; i++)
 130     {
 131       if (CANNOT_FETCH_REGISTER (i))
 132         supply_register (i, NULL);
 133       else
 134         supply_register (i, REG_ADDR (gregsetp, i));
 135     }
 136 }
 137
 138 /* Fill register REGNO (if it is a general-purpose register) in
 139    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 140    do this for all registers.  */
 141
 142 void
 143 fill_gregset (gregset_t *gregsetp, int regno)
 144 {
 145   int i;
 146
 147   for (i = 0; i < I386_NUM_GREGS; i++)
 148     if ((regno == -1 || regno == i) && ! CANNOT_STORE_REGISTER (i))
 149       regcache_collect (i, REG_ADDR (gregsetp, i));
 150 }
 151
 152 #include "i387-tdep.h"
 153
 154 /* Fill GDB's register array with the floating-point register values
 155    in *FPREGSETP.  */
 156
 157 void
 158 supply_fpregset (fpregset_t *fpregsetp)
 159 {
 160   i387_supply_fsave ((const char *) fpregsetp, -1);
 161 }
 162
 163 /* Fill register REGNO (if it is a floating-point register) in
 164    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 165    do this for all registers.  */
 166
 167 void
 168 fill_fpregset (fpregset_t *fpregsetp, int regno)
 169 {
 170   i387_fill_fsave ((char *) fpregsetp, regno);
 171 }
 172
 173 /* Fetch register REGNO from the inferior.  If REGNO is -1, do this
 174    for all registers (including the floating point registers).  */
 175
 176 void
 177 fetch_inferior_registers (int regno)
 178 {
 179   if (regno == -1 || GETREGS_SUPPLIES (regno))
 180     {
 181       gregset_t gregs;
 182
 183       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 184                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 185         perror_with_name ("Couldn't get registers");
 186
 187       supply_gregset (&gregs);
 188       if (regno != -1)
 189         return;
 190     }
 191
 192   if (regno == -1 || regno >= FP0_REGNUM)
 193     {
 194       fpregset_t fpregs;
 195 #ifdef HAVE_PT_GETXMMREGS
 196       char xmmregs[512];
 197
 198       if (have_ptrace_xmmregs != 0
 199           && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 200                     (PTRACE_ARG3_TYPE) xmmregs, 0) == 0)
 201         {
 202           have_ptrace_xmmregs = 1;
 203           i387_supply_fxsave (xmmregs, -1);
 204         }
 205       else
 206         {
 207           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 208                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 209             perror_with_name ("Couldn't get floating point status");
 210
 211           i387_supply_fsave ((const char *) &fpregs, -1);
 212         }
 213 #else
 214       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 215                   (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 216         perror_with_name ("Couldn't get floating point status");
 217
 218       i387_supply_fsave ((const char *) &fpregs, -1);
 219 #endif
 220     }
 221 }
 222
 223 /* Store register REGNO back into the inferior.  If REGNO is -1, do
 224    this for all registers (including the floating point registers).  */
 225
 226 void
 227 store_inferior_registers (int regno)
 228 {
 229   if (regno == -1 || GETREGS_SUPPLIES (regno))
 230     {
 231       gregset_t gregs;
 232
 233       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 234                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 235         perror_with_name ("Couldn't get registers");
 236
 237       fill_gregset (&gregs, regno);
 238
 239       if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 240                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 241         perror_with_name ("Couldn't write registers");
 242
 243       if (regno != -1)
 244         return;
 245     }
 246
 247   if (regno == -1 || regno >= FP0_REGNUM)
 248     {
 249       fpregset_t fpregs;
 250 #ifdef HAVE_PT_GETXMMREGS
 251       char xmmregs[512];
 252
 253       if (have_ptrace_xmmregs != 0
 254           && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 255                     (PTRACE_ARG3_TYPE) xmmregs, 0) == 0)
 256         {
 257           have_ptrace_xmmregs = 1;
 258
 259           i387_fill_fxsave (xmmregs, regno);
 260
 261           if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
 262                       (PTRACE_ARG3_TYPE) xmmregs, 0) == -1)
 263             perror_with_name ("Couldn't write XMM registers");
 264         }
 265       else
 266         {
 267           have_ptrace_xmmregs = 0;
 268 #endif
 269           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 270                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 271             perror_with_name ("Couldn't get floating point status");
 272
 273           i387_fill_fsave ((char *) &fpregs, regno);
 274
 275           if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 276                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 277             perror_with_name ("Couldn't write floating point status");
 278 #ifdef HAVE_PT_GETXMMREGS
 279         }
 280 #endif
 281     }
 282 }
 283 \f
 284
 285 /* Support for debug registers.  */
 286
 287 #ifdef HAVE_PT_GETDBREGS
 288
 289 /* Not all versions of FreeBSD/i386 that support the debug registers
 290    have this macro.  */
 291 #ifndef DBREG_DRX
 292 #define DBREG_DRX(d, x) ((&d->dr0)[x])
 293 #endif
 294
 295 static void
 296 i386bsd_dr_set (int regnum, unsigned int value)
 297 {
 298   struct dbreg dbregs;
 299
 300   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 301               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 302     perror_with_name ("Couldn't get debug registers");
 303
 304   /* For some mysterious reason, some of the reserved bits in the
 305      debug control register get set.  Mask these off, otherwise the
 306      ptrace call below will fail.  */
 307   DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
 308
 309   DBREG_DRX ((&dbregs), regnum) = value;
 310
 311   if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
 312               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 313     perror_with_name ("Couldn't write debug registers");
 314 }
 315
 316 void
 317 i386bsd_dr_set_control (unsigned long control)
 318 {
 319   i386bsd_dr_set (7, control);
 320 }
 321
 322 void
 323 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 324 {
 325   gdb_assert (regnum >= 0 && regnum <= 4);
 326
 327   i386bsd_dr_set (regnum, addr);
 328 }
 329
 330 void
 331 i386bsd_dr_reset_addr (int regnum)
 332 {
 333   gdb_assert (regnum >= 0 && regnum <= 4);
 334
 335   i386bsd_dr_set (regnum, 0);
 336 }
 337
 338 unsigned long
 339 i386bsd_dr_get_status (void)
 340 {
 341   struct dbreg dbregs;
 342
 343   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
 344      ptrace call fails breaks debugging remote targets.  The correct
 345      way to fix this is to add the hardware breakpoint and watchpoint
 346      stuff to the target vector.  For now, just return zero if the
 347      ptrace call fails.  */
 348   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 349               (PTRACE_ARG3_TYPE) & dbregs, 0) == -1)
 350 #if 0
 351     perror_with_name ("Couldn't read debug registers");
 352 #else
 353     return 0;
 354 #endif
 355
 356   return DBREG_DRX ((&dbregs), 6);
 357 }
 358
 359 #endif /* PT_GETDBREGS */
 360 \f
 361
 362 /* Support for the user struct.  */
 363
 364 /* Return the address register REGNO.  BLOCKEND is the value of
 365    u.u_ar0, which should point to the registers.  */
 366
 367 CORE_ADDR
 368 register_u_addr (CORE_ADDR blockend, int regno)
 369 {
 370   return (CORE_ADDR) REG_ADDR (blockend, regno);
 371 }
 372
 373 #include <sys/param.h>
 374 #include <sys/user.h>
 375
 376 /* Return the size of the user struct.  */
 377
 378 int
 379 kernel_u_size (void)
 380 {
 381   return (sizeof (struct user));
 382 }
 383 \f
 384 void
 385 _initialize_i386bsd_nat (void)
 386 {
 387   int offset;
 388
 389   /* To support the recognition of signal handlers, i386bsd-tdep.c
 390      hardcodes some constants.  Inclusion of this file means that we
 391      are compiling a native debugger, which means that we can use the
 392      system header files and sysctl(3) to get at the relevant
 393      information.  */
 394
 395 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 396 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 397 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 398 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 399 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 400 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 401 #elif defined (OpenBSD)
 402 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 403 #else
 404 #define SC_REG_OFFSET i386bsd_sc_reg_offset
 405 #endif
 406
 407   /* We only check the program counter, stack pointer and frame
 408      pointer since these members of `struct sigcontext' are essential
 409      for providing backtraces.  More checks could be added, but would
 410      involve adding configure checks for the appropriate structure
 411      members, since older BSD's don't provide all of them.  */
 412
 413 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 414 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 415 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 416
 417   /* Override the default value for the offset of the program counter
 418      in the sigcontext structure.  */
 419   offset = offsetof (struct sigcontext, sc_pc);
 420
 421   if (SC_PC_OFFSET != offset)
 422     {
 423       warning ("\
 424 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 425 Please report this to <bug-gdb@gnu.org>.",
 426                offset, SC_PC_OFFSET);
 427     }
 428
 429   SC_PC_OFFSET = offset;
 430
 431   /* Likewise for the stack pointer.  */
 432   offset = offsetof (struct sigcontext, sc_sp);
 433
 434   if (SC_SP_OFFSET != offset)
 435     {
 436       warning ("\
 437 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 438 Please report this to <bug-gdb@gnu.org>.",
 439                offset, SC_SP_OFFSET);
 440     }
 441
 442   SC_SP_OFFSET = offset;
 443
 444   /* And the frame pointer.  */
 445   offset = offsetof (struct sigcontext, sc_fp);
 446
 447   if (SC_FP_OFFSET != offset)
 448     {
 449       warning ("\
 450 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 451 Please report this to <bug-gdb@gnu.org>.",
 452                offset, SC_FP_OFFSET);
 453     }
 454
 455   SC_FP_OFFSET = offset;
 456 }