gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2    Copyright 2000, 2001, 2002 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 \f
  47
  48 /* In older BSD versions we cannot get at some of the segment
  49    registers.  FreeBSD for example didn't support the %fs and %gs
  50    registers until the 3.0 release.  We have autoconf checks for their
  51    presence, and deal gracefully with their absence.  */
  52
  53 /* Registers we shouldn't try to fetch.  */
  54 #if !defined (CANNOT_FETCH_REGISTER)
  55 #define CANNOT_FETCH_REGISTER(regno) cannot_fetch_register (regno)
  56 #endif
  57
  58 /* Registers we shouldn't try to store.  */
  59 #if !defined (CANNOT_STORE_REGISTER)
  60 #define CANNOT_STORE_REGISTER(regno) cannot_fetch_register (regno)
  61 #endif
  62
  63 /* Offset to the gregset_t location where REG is stored.  */
  64 #define REG_OFFSET(reg) offsetof (gregset_t, reg)
  65
  66 /* At reg_offset[REGNO] you'll find the offset to the gregset_t
  67    location where the GDB register REGNO is stored.  Unsupported
  68    registers are marked with `-1'.  */
  69 static int reg_offset[] =
  70 {
  71   REG_OFFSET (r_eax),
  72   REG_OFFSET (r_ecx),
  73   REG_OFFSET (r_edx),
  74   REG_OFFSET (r_ebx),
  75   REG_OFFSET (r_esp),
  76   REG_OFFSET (r_ebp),
  77   REG_OFFSET (r_esi),
  78   REG_OFFSET (r_edi),
  79   REG_OFFSET (r_eip),
  80   REG_OFFSET (r_eflags),
  81   REG_OFFSET (r_cs),
  82   REG_OFFSET (r_ss),
  83   REG_OFFSET (r_ds),
  84   REG_OFFSET (r_es),
  85 #ifdef HAVE_STRUCT_REG_R_FS
  86   REG_OFFSET (r_fs),
  87 #else
  88   -1,
  89 #endif
  90 #ifdef HAVE_STRUCT_REG_R_GS
  91   REG_OFFSET (r_gs)
  92 #else
  93   -1
  94 #endif
  95 };
  96
  97 #define REG_ADDR(regset, regno) ((char *) (regset) + reg_offset[regno])
  98
  99 /* Macro to determine if a register is fetched with PT_GETREGS.  */
 100 #define GETREGS_SUPPLIES(regno) \
 101   ((0 <= (regno) && (regno) <= 15))
 102
 103 #ifdef HAVE_PT_GETXMMREGS
 104 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
 105    so that we try PT_GETXMMREGS the first time around.  */
 106 static int have_ptrace_xmmregs = -1;
 107 #endif
 108
 109 /* Return nonzero if we shouldn't try to fetch register REGNO.  */
 110
 111 static int
 112 cannot_fetch_register (int regno)
 113 {
 114   return (reg_offset[regno] == -1);
 115 }
 116 \f
 117
 118 /* Transfering the registers between GDB, inferiors and core files.  */
 119
 120 /* Fill GDB's register array with the general-purpose register values
 121    in *GREGSETP.  */
 122
 123 void
 124 supply_gregset (gregset_t *gregsetp)
 125 {
 126   int i;
 127
 128   for (i = 0; i < NUM_GREGS; i++)
 129     {
 130       if (CANNOT_FETCH_REGISTER (i))
 131         supply_register (i, NULL);
 132       else
 133         supply_register (i, REG_ADDR (gregsetp, i));
 134     }
 135 }
 136
 137 /* Fill register REGNO (if it is a general-purpose register) in
 138    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 139    do this for all registers.  */
 140
 141 void
 142 fill_gregset (gregset_t *gregsetp, int regno)
 143 {
 144   int i;
 145
 146   for (i = 0; i < NUM_GREGS; i++)
 147     if ((regno == -1 || regno == i) && ! CANNOT_STORE_REGISTER (i))
 148       regcache_collect (i, REG_ADDR (gregsetp, i));
 149 }
 150
 151 #include "i387-tdep.h"
 152
 153 /* Fill GDB's register array with the floating-point register values
 154    in *FPREGSETP.  */
 155
 156 void
 157 supply_fpregset (fpregset_t *fpregsetp)
 158 {
 159   i387_supply_fsave ((char *) fpregsetp);
 160 }
 161
 162 /* Fill register REGNO (if it is a floating-point register) in
 163    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 164    do this for all registers.  */
 165
 166 void
 167 fill_fpregset (fpregset_t *fpregsetp, int regno)
 168 {
 169   i387_fill_fsave ((char *) fpregsetp, regno);
 170 }
 171
 172 /* Fetch register REGNO from the inferior.  If REGNO is -1, do this
 173    for all registers (including the floating point registers).  */
 174
 175 void
 176 fetch_inferior_registers (int regno)
 177 {
 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);
 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           supply_fpregset (&fpregs);
 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       supply_fpregset (&fpregs);
 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
 230   if (regno == -1 || GETREGS_SUPPLIES (regno))
 231     {
 232       gregset_t gregs;
 233
 234       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 235                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 236         perror_with_name ("Couldn't get registers");
 237
 238       fill_gregset (&gregs, regno);
 239
 240       if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 241                   (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 242         perror_with_name ("Couldn't write registers");
 243
 244       if (regno != -1)
 245         return;
 246     }
 247
 248   if (regno == -1 || regno >= FP0_REGNUM)
 249     {
 250       fpregset_t fpregs;
 251 #ifdef HAVE_PT_GETXMMREGS
 252       char xmmregs[512];
 253
 254       if (have_ptrace_xmmregs != 0 &&
 255           ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 256                  (PTRACE_ARG3_TYPE) xmmregs, 0) == 0)
 257         {
 258           have_ptrace_xmmregs = 1;
 259
 260           i387_fill_fxsave (xmmregs, regno);
 261
 262           if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
 263                       (PTRACE_ARG3_TYPE) xmmregs, 0) == -1)
 264             perror_with_name ("Couldn't write XMM registers");
 265         }
 266       else
 267         {
 268           have_ptrace_xmmregs = 0;
 269 #endif
 270           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 271                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 272             perror_with_name ("Couldn't get floating point status");
 273
 274           fill_fpregset (&fpregs, regno);
 275
 276           if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 277                       (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 278             perror_with_name ("Couldn't write floating point status");
 279 #ifdef HAVE_PT_GETXMMREGS
 280         }
 281 #endif
 282     }
 283 }
 284 \f
 285
 286 /* Support for debug registers.  */
 287
 288 #ifdef HAVE_PT_GETDBREGS
 289
 290 /* Not all versions of FreeBSD/i386 that support the debug registers
 291    have this macro.  */
 292 #ifndef DBREG_DRX
 293 #define DBREG_DRX(d, x) ((&d->dr0)[x])
 294 #endif
 295
 296 static void
 297 i386bsd_dr_set (int regnum, unsigned int value)
 298 {
 299   struct dbreg dbregs;
 300
 301   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 302               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 303     perror_with_name ("Couldn't get debug registers");
 304
 305   /* For some mysterious reason, some of the reserved bits in the
 306      debug control register get set.  Mask these off, otherwise the
 307      ptrace call below will fail.  */
 308   dbregs.dr7 &= ~(0x0000fc00);
 309
 310   DBREG_DRX ((&dbregs), regnum) = value;
 311
 312   if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
 313               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 314     perror_with_name ("Couldn't write debug registers");
 315 }
 316
 317 void
 318 i386bsd_dr_set_control (unsigned long control)
 319 {
 320   i386bsd_dr_set (7, control);
 321 }
 322
 323 void
 324 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 325 {
 326   gdb_assert (regnum >= 0 && regnum <= 4);
 327
 328   i386bsd_dr_set (regnum, addr);
 329 }
 330
 331 void
 332 i386bsd_dr_reset_addr (int regnum)
 333 {
 334   gdb_assert (regnum >= 0 && regnum <= 4);
 335
 336   i386bsd_dr_set (regnum, 0);
 337 }
 338
 339 unsigned long
 340 i386bsd_dr_get_status (void)
 341 {
 342   struct dbreg dbregs;
 343
 344   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
 345      ptrace call fails breaks debugging remote targets.  The correct
 346      way to fix this is to add the hardware breakpoint and watchpoint
 347      stuff to the target vector.  For now, just return zero if the
 348      ptrace call fails.  */
 349   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 350               (PTRACE_ARG3_TYPE) & dbregs, 0) == -1)
 351 #if 0
 352     perror_with_name ("Couldn't read debug registers");
 353 #else
 354     return 0;
 355 #endif
 356
 357   return dbregs.dr6;
 358 }
 359
 360 #endif /* PT_GETDBREGS */
 361 \f
 362
 363 /* Support for the user struct.  */
 364
 365 /* Return the address register REGNO.  BLOCKEND is the value of
 366    u.u_ar0, which should point to the registers.  */
 367
 368 CORE_ADDR
 369 register_u_addr (CORE_ADDR blockend, int regno)
 370 {
 371   return (CORE_ADDR) REG_ADDR (blockend, regno);
 372 }
 373
 374 #include <sys/param.h>
 375 #include <sys/user.h>
 376
 377 /* Return the size of the user struct.  */
 378
 379 int
 380 kernel_u_size (void)
 381 {
 382   return (sizeof (struct user));
 383 }
 384 \f
 385 /* See i386bsd-tdep.c.  */
 386 extern int i386bsd_sigcontext_pc_offset;
 387
 388 void
 389 _initialize_i386bsd_nat (void)
 390 {
 391   /* To support the recognition of signal handlers, i386bsd-tdep.c
 392      hardcodes some constants.  Inclusion of this file means that we
 393      are compiling a native debugger, which means that we can use the
 394      system header files and sysctl(3) to get at the relevant
 395      information.  */
 396
 397   /* Override the default value for the offset of the program counter
 398      in the sigcontext structure.  */
 399   i386bsd_sigcontext_pc_offset = offsetof (struct sigcontext, sc_pc);
 400 }