gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2
   3    Copyright 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "regcache.h"
  25
  26 #include "gdb_assert.h"
  27 #include <signal.h>
  28 #include <stddef.h>
  29 #include <sys/types.h>
  30 #include <sys/ptrace.h>
  31 #include <machine/reg.h>
  32 #include <machine/frame.h>
  33
  34 #include "i386-tdep.h"
  35 #include "i387-tdep.h"
  36 #include "i386bsd-nat.h"
  37 #include "inf-ptrace.h"
  38 \f
  39
  40 /* In older BSD versions we cannot get at some of the segment
  41    registers.  FreeBSD for example didn't support the %fs and %gs
  42    registers until the 3.0 release.  We have autoconf checks for their
  43    presence, and deal gracefully with their absence.  */
  44
  45 /* Offset in `struct reg' where MEMBER is stored.  */
  46 #define REG_OFFSET(member) offsetof (struct reg, member)
  47
  48 /* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct
  49    reg' where the GDB register REGNUM is stored.  Unsupported
  50    registers are marked with `-1'.  */
  51 static int i386bsd_r_reg_offset[] =
  52 {
  53   REG_OFFSET (r_eax),
  54   REG_OFFSET (r_ecx),
  55   REG_OFFSET (r_edx),
  56   REG_OFFSET (r_ebx),
  57   REG_OFFSET (r_esp),
  58   REG_OFFSET (r_ebp),
  59   REG_OFFSET (r_esi),
  60   REG_OFFSET (r_edi),
  61   REG_OFFSET (r_eip),
  62   REG_OFFSET (r_eflags),
  63   REG_OFFSET (r_cs),
  64   REG_OFFSET (r_ss),
  65   REG_OFFSET (r_ds),
  66   REG_OFFSET (r_es),
  67 #ifdef HAVE_STRUCT_REG_R_FS
  68   REG_OFFSET (r_fs),
  69 #else
  70   -1,
  71 #endif
  72 #ifdef HAVE_STRUCT_REG_R_GS
  73   REG_OFFSET (r_gs)
  74 #else
  75   -1
  76 #endif
  77 };
  78
  79 /* Macro to determine if a register is fetched with PT_GETREGS.  */
  80 #define GETREGS_SUPPLIES(regnum) \
  81   ((0 <= (regnum) && (regnum) <= 15))
  82
  83 #ifdef HAVE_PT_GETXMMREGS
  84 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
  85    so that we try PT_GETXMMREGS the first time around.  */
  86 static int have_ptrace_xmmregs = -1;
  87 #endif
  88 \f
  89
  90 /* Supply the general-purpose registers in GREGS, to REGCACHE.  */
  91
  92 static void
  93 i386bsd_supply_gregset (struct regcache *regcache, const void *gregs)
  94 {
  95   const char *regs = gregs;
  96   int regnum;
  97
  98   for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++)
  99     {
 100       int offset = i386bsd_r_reg_offset[regnum];
 101
 102       if (offset != -1)
 103         regcache_raw_supply (regcache, regnum, regs + offset);
 104     }
 105 }
 106
 107 /* Collect register REGNUM from REGCACHE and store its contents in
 108    GREGS.  If REGNUM is -1, collect and store all appropriate
 109    registers.  */
 110
 111 static void
 112 i386bsd_collect_gregset (const struct regcache *regcache,
 113                          void *gregs, int regnum)
 114 {
 115   char *regs = gregs;
 116   int i;
 117
 118   for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++)
 119     {
 120       if (regnum == -1 || regnum == i)
 121         {
 122           int offset = i386bsd_r_reg_offset[i];
 123
 124           if (offset != -1)
 125             regcache_raw_collect (regcache, i, regs + offset);
 126         }
 127     }
 128 }
 129
 130 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 131    for all registers (including the floating point registers).  */
 132
 133 static void
 134 i386bsd_fetch_inferior_registers (int regnum)
 135 {
 136   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 137     {
 138       struct reg regs;
 139
 140       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 141                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 142         perror_with_name ("Couldn't get registers");
 143
 144       i386bsd_supply_gregset (current_regcache, &regs);
 145       if (regnum != -1)
 146         return;
 147     }
 148
 149   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 150     {
 151       struct fpreg fpregs;
 152 #ifdef HAVE_PT_GETXMMREGS
 153       char xmmregs[512];
 154
 155       if (have_ptrace_xmmregs != 0
 156           && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 157                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 158         {
 159           have_ptrace_xmmregs = 1;
 160           i387_supply_fxsave (current_regcache, -1, xmmregs);
 161         }
 162       else
 163         {
 164           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 165                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 166             perror_with_name ("Couldn't get floating point status");
 167
 168           i387_supply_fsave (current_regcache, -1, &fpregs);
 169         }
 170 #else
 171       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 172                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 173         perror_with_name ("Couldn't get floating point status");
 174
 175       i387_supply_fsave (current_regcache, -1, &fpregs);
 176 #endif
 177     }
 178 }
 179
 180 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 181    this for all registers (including the floating point registers).  */
 182
 183 static void
 184 i386bsd_store_inferior_registers (int regnum)
 185 {
 186   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 187     {
 188       struct reg regs;
 189
 190       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 191                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 192         perror_with_name ("Couldn't get registers");
 193
 194       i386bsd_collect_gregset (current_regcache, &regs, regnum);
 195
 196       if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 197                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 198         perror_with_name ("Couldn't write registers");
 199
 200       if (regnum != -1)
 201         return;
 202     }
 203
 204   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 205     {
 206       struct fpreg fpregs;
 207 #ifdef HAVE_PT_GETXMMREGS
 208       char xmmregs[512];
 209
 210       if (have_ptrace_xmmregs != 0
 211           && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 212                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 213         {
 214           have_ptrace_xmmregs = 1;
 215
 216           i387_collect_fxsave (current_regcache, regnum, xmmregs);
 217
 218           if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
 219                       (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
 220             perror_with_name ("Couldn't write XMM registers");
 221         }
 222       else
 223         {
 224           have_ptrace_xmmregs = 0;
 225 #endif
 226           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 227                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 228             perror_with_name ("Couldn't get floating point status");
 229
 230           i387_collect_fsave (current_regcache, regnum, &fpregs);
 231
 232           if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 233                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 234             perror_with_name ("Couldn't write floating point status");
 235 #ifdef HAVE_PT_GETXMMREGS
 236         }
 237 #endif
 238     }
 239 }
 240
 241 /* Create a prototype *BSD/i386 target.  The client can override it
 242    with local methods.  */
 243
 244 struct target_ops *
 245 i386bsd_target (void)
 246 {
 247   struct target_ops *t;
 248
 249   t = inf_ptrace_target ();
 250   t->to_fetch_registers = i386bsd_fetch_inferior_registers;
 251   t->to_store_registers = i386bsd_store_inferior_registers;
 252   return t;
 253 }
 254 \f
 255
 256 /* Support for debug registers.  */
 257
 258 #ifdef HAVE_PT_GETDBREGS
 259
 260 /* Not all versions of FreeBSD/i386 that support the debug registers
 261    have this macro.  */
 262 #ifndef DBREG_DRX
 263 #define DBREG_DRX(d, x) ((&d->dr0)[x])
 264 #endif
 265
 266 static void
 267 i386bsd_dr_set (int regnum, unsigned int value)
 268 {
 269   struct dbreg dbregs;
 270
 271   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 272               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 273     perror_with_name ("Couldn't get debug registers");
 274
 275   /* For some mysterious reason, some of the reserved bits in the
 276      debug control register get set.  Mask these off, otherwise the
 277      ptrace call below will fail.  */
 278   DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
 279
 280   DBREG_DRX ((&dbregs), regnum) = value;
 281
 282   if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
 283               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 284     perror_with_name ("Couldn't write debug registers");
 285 }
 286
 287 void
 288 i386bsd_dr_set_control (unsigned long control)
 289 {
 290   i386bsd_dr_set (7, control);
 291 }
 292
 293 void
 294 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 295 {
 296   gdb_assert (regnum >= 0 && regnum <= 4);
 297
 298   i386bsd_dr_set (regnum, addr);
 299 }
 300
 301 void
 302 i386bsd_dr_reset_addr (int regnum)
 303 {
 304   gdb_assert (regnum >= 0 && regnum <= 4);
 305
 306   i386bsd_dr_set (regnum, 0);
 307 }
 308
 309 unsigned long
 310 i386bsd_dr_get_status (void)
 311 {
 312   struct dbreg dbregs;
 313
 314   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
 315      ptrace call fails breaks debugging remote targets.  The correct
 316      way to fix this is to add the hardware breakpoint and watchpoint
 317      stuff to the target vector.  For now, just return zero if the
 318      ptrace call fails.  */
 319   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 320               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 321 #if 0
 322     perror_with_name ("Couldn't read debug registers");
 323 #else
 324     return 0;
 325 #endif
 326
 327   return DBREG_DRX ((&dbregs), 6);
 328 }
 329
 330 #endif /* PT_GETDBREGS */
 331 \f
 332
 333 /* Support for the user struct.  */
 334
 335 /* Return the address register REGNUM.  BLOCKEND is the value of
 336    u.u_ar0, which should point to the registers.  */
 337
 338 CORE_ADDR
 339 register_u_addr (CORE_ADDR blockend, int regnum)
 340 {
 341   gdb_assert (regnum >= 0 && regnum < ARRAY_SIZE (i386bsd_r_reg_offset));
 342
 343   return blockend + i386bsd_r_reg_offset[regnum];
 344 }
 345
 346 #include <sys/param.h>
 347 #include <sys/user.h>
 348
 349 /* Return the size of the user struct.  */
 350
 351 int
 352 kernel_u_size (void)
 353 {
 354   return (sizeof (struct user));
 355 }
 356 \f
 357 void
 358 _initialize_i386bsd_nat (void)
 359 {
 360   int offset;
 361
 362   /* To support the recognition of signal handlers, i386bsd-tdep.c
 363      hardcodes some constants.  Inclusion of this file means that we
 364      are compiling a native debugger, which means that we can use the
 365      system header files and sysctl(3) to get at the relevant
 366      information.  */
 367
 368 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 369 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 370 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 371 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 372 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 373 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 374 #elif defined (OpenBSD)
 375 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 376 #endif
 377
 378 #ifdef SC_REG_OFFSET
 379
 380   /* We only check the program counter, stack pointer and frame
 381      pointer since these members of `struct sigcontext' are essential
 382      for providing backtraces.  More checks could be added, but would
 383      involve adding configure checks for the appropriate structure
 384      members, since older BSD's don't provide all of them.  */
 385
 386 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 387 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 388 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 389
 390   /* Override the default value for the offset of the program counter
 391      in the sigcontext structure.  */
 392   offset = offsetof (struct sigcontext, sc_pc);
 393
 394   if (SC_PC_OFFSET != offset)
 395     {
 396       warning ("\
 397 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 398 Please report this to <bug-gdb@gnu.org>.",
 399                offset, SC_PC_OFFSET);
 400     }
 401
 402   SC_PC_OFFSET = offset;
 403
 404   /* Likewise for the stack pointer.  */
 405   offset = offsetof (struct sigcontext, sc_sp);
 406
 407   if (SC_SP_OFFSET != offset)
 408     {
 409       warning ("\
 410 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 411 Please report this to <bug-gdb@gnu.org>.",
 412                offset, SC_SP_OFFSET);
 413     }
 414
 415   SC_SP_OFFSET = offset;
 416
 417   /* And the frame pointer.  */
 418   offset = offsetof (struct sigcontext, sc_fp);
 419
 420   if (SC_FP_OFFSET != offset)
 421     {
 422       warning ("\
 423 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 424 Please report this to <bug-gdb@gnu.org>.",
 425                offset, SC_FP_OFFSET);
 426     }
 427
 428   SC_FP_OFFSET = offset;
 429
 430 #endif /* SC_REG_OFFSET */
 431 }