gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2
   3    Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  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 #include "i386-tdep.h"
  34 #include "i387-tdep.h"
  35 #include "i386bsd-nat.h"
  36 #include "inf-ptrace.h"
  37 \f
  38
  39 /* In older BSD versions we cannot get at some of the segment
  40    registers.  FreeBSD for example didn't support the %fs and %gs
  41    registers until the 3.0 release.  We have autoconf checks for their
  42    presence, and deal gracefully with their absence.  */
  43
  44 /* Offset in `struct reg' where MEMBER is stored.  */
  45 #define REG_OFFSET(member) offsetof (struct reg, member)
  46
  47 /* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct
  48    reg' where the GDB register REGNUM is stored.  Unsupported
  49    registers are marked with `-1'.  */
  50 static int i386bsd_r_reg_offset[] =
  51 {
  52   REG_OFFSET (r_eax),
  53   REG_OFFSET (r_ecx),
  54   REG_OFFSET (r_edx),
  55   REG_OFFSET (r_ebx),
  56   REG_OFFSET (r_esp),
  57   REG_OFFSET (r_ebp),
  58   REG_OFFSET (r_esi),
  59   REG_OFFSET (r_edi),
  60   REG_OFFSET (r_eip),
  61   REG_OFFSET (r_eflags),
  62   REG_OFFSET (r_cs),
  63   REG_OFFSET (r_ss),
  64   REG_OFFSET (r_ds),
  65   REG_OFFSET (r_es),
  66 #ifdef HAVE_STRUCT_REG_R_FS
  67   REG_OFFSET (r_fs),
  68 #else
  69   -1,
  70 #endif
  71 #ifdef HAVE_STRUCT_REG_R_GS
  72   REG_OFFSET (r_gs)
  73 #else
  74   -1
  75 #endif
  76 };
  77
  78 /* Macro to determine if a register is fetched with PT_GETREGS.  */
  79 #define GETREGS_SUPPLIES(regnum) \
  80   ((0 <= (regnum) && (regnum) <= 15))
  81
  82 #ifdef HAVE_PT_GETXMMREGS
  83 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
  84    so that we try PT_GETXMMREGS the first time around.  */
  85 static int have_ptrace_xmmregs = -1;
  86 #endif
  87 \f
  88
  89 /* Supply the general-purpose registers in GREGS, to REGCACHE.  */
  90
  91 static void
  92 i386bsd_supply_gregset (struct regcache *regcache, const void *gregs)
  93 {
  94   const char *regs = gregs;
  95   int regnum;
  96
  97   for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++)
  98     {
  99       int offset = i386bsd_r_reg_offset[regnum];
 100
 101       if (offset != -1)
 102         regcache_raw_supply (regcache, regnum, regs + offset);
 103     }
 104 }
 105
 106 /* Collect register REGNUM from REGCACHE and store its contents in
 107    GREGS.  If REGNUM is -1, collect and store all appropriate
 108    registers.  */
 109
 110 static void
 111 i386bsd_collect_gregset (const struct regcache *regcache,
 112                          void *gregs, int regnum)
 113 {
 114   char *regs = gregs;
 115   int i;
 116
 117   for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++)
 118     {
 119       if (regnum == -1 || regnum == i)
 120         {
 121           int offset = i386bsd_r_reg_offset[i];
 122
 123           if (offset != -1)
 124             regcache_raw_collect (regcache, i, regs + offset);
 125         }
 126     }
 127 }
 128
 129 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 130    for all registers (including the floating point registers).  */
 131
 132 static void
 133 i386bsd_fetch_inferior_registers (struct regcache *regcache, int regnum)
 134 {
 135   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 136     {
 137       struct reg regs;
 138
 139       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 140                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 141         perror_with_name (_("Couldn't get registers"));
 142
 143       i386bsd_supply_gregset (regcache, &regs);
 144       if (regnum != -1)
 145         return;
 146     }
 147
 148   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 149     {
 150       struct fpreg fpregs;
 151 #ifdef HAVE_PT_GETXMMREGS
 152       char xmmregs[512];
 153
 154       if (have_ptrace_xmmregs != 0
 155           && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 156                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 157         {
 158           have_ptrace_xmmregs = 1;
 159           i387_supply_fxsave (regcache, -1, xmmregs);
 160         }
 161       else
 162         {
 163           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 164                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 165             perror_with_name (_("Couldn't get floating point status"));
 166
 167           i387_supply_fsave (regcache, -1, &fpregs);
 168         }
 169 #else
 170       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 171                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 172         perror_with_name (_("Couldn't get floating point status"));
 173
 174       i387_supply_fsave (regcache, -1, &fpregs);
 175 #endif
 176     }
 177 }
 178
 179 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 180    this for all registers (including the floating point registers).  */
 181
 182 static void
 183 i386bsd_store_inferior_registers (struct regcache *regcache, int regnum)
 184 {
 185   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 186     {
 187       struct reg regs;
 188
 189       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 190                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 191         perror_with_name (_("Couldn't get registers"));
 192
 193       i386bsd_collect_gregset (regcache, &regs, regnum);
 194
 195       if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 196                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 197         perror_with_name (_("Couldn't write registers"));
 198
 199       if (regnum != -1)
 200         return;
 201     }
 202
 203   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 204     {
 205       struct fpreg fpregs;
 206 #ifdef HAVE_PT_GETXMMREGS
 207       char xmmregs[512];
 208
 209       if (have_ptrace_xmmregs != 0
 210           && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 211                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 212         {
 213           have_ptrace_xmmregs = 1;
 214
 215           i387_collect_fxsave (regcache, regnum, xmmregs);
 216
 217           if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
 218                       (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
 219             perror_with_name (_("Couldn't write XMM registers"));
 220         }
 221       else
 222         {
 223           have_ptrace_xmmregs = 0;
 224 #endif
 225           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 226                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 227             perror_with_name (_("Couldn't get floating point status"));
 228
 229           i387_collect_fsave (regcache, regnum, &fpregs);
 230
 231           if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 232                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 233             perror_with_name (_("Couldn't write floating point status"));
 234 #ifdef HAVE_PT_GETXMMREGS
 235         }
 236 #endif
 237     }
 238 }
 239
 240 /* Create a prototype *BSD/i386 target.  The client can override it
 241    with local methods.  */
 242
 243 struct target_ops *
 244 i386bsd_target (void)
 245 {
 246   struct target_ops *t;
 247
 248   t = inf_ptrace_target ();
 249   t->to_fetch_registers = i386bsd_fetch_inferior_registers;
 250   t->to_store_registers = i386bsd_store_inferior_registers;
 251   return t;
 252 }
 253 \f
 254
 255 /* Support for debug registers.  */
 256
 257 #ifdef HAVE_PT_GETDBREGS
 258
 259 /* Not all versions of FreeBSD/i386 that support the debug registers
 260    have this macro.  */
 261 #ifndef DBREG_DRX
 262 #define DBREG_DRX(d, x) ((&d->dr0)[x])
 263 #endif
 264
 265 static void
 266 i386bsd_dr_set (int regnum, unsigned int value)
 267 {
 268   struct dbreg dbregs;
 269
 270   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 271               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 272     perror_with_name (_("Couldn't get debug registers"));
 273
 274   /* For some mysterious reason, some of the reserved bits in the
 275      debug control register get set.  Mask these off, otherwise the
 276      ptrace call below will fail.  */
 277   DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
 278
 279   DBREG_DRX ((&dbregs), regnum) = value;
 280
 281   if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
 282               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 283     perror_with_name (_("Couldn't write debug registers"));
 284 }
 285
 286 void
 287 i386bsd_dr_set_control (unsigned long control)
 288 {
 289   i386bsd_dr_set (7, control);
 290 }
 291
 292 void
 293 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 294 {
 295   gdb_assert (regnum >= 0 && regnum <= 4);
 296
 297   i386bsd_dr_set (regnum, addr);
 298 }
 299
 300 void
 301 i386bsd_dr_reset_addr (int regnum)
 302 {
 303   gdb_assert (regnum >= 0 && regnum <= 4);
 304
 305   i386bsd_dr_set (regnum, 0);
 306 }
 307
 308 unsigned long
 309 i386bsd_dr_get_status (void)
 310 {
 311   struct dbreg dbregs;
 312
 313   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
 314      ptrace call fails breaks debugging remote targets.  The correct
 315      way to fix this is to add the hardware breakpoint and watchpoint
 316      stuff to the target vector.  For now, just return zero if the
 317      ptrace call fails.  */
 318   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 319               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 320 #if 0
 321     perror_with_name (_("Couldn't read debug registers"));
 322 #else
 323     return 0;
 324 #endif
 325
 326   return DBREG_DRX ((&dbregs), 6);
 327 }
 328
 329 #endif /* PT_GETDBREGS */
 330 \f
 331
 332 void
 333 _initialize_i386bsd_nat (void)
 334 {
 335   int offset;
 336
 337   /* To support the recognition of signal handlers, i386bsd-tdep.c
 338      hardcodes some constants.  Inclusion of this file means that we
 339      are compiling a native debugger, which means that we can use the
 340      system header files and sysctl(3) to get at the relevant
 341      information.  */
 342
 343 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 344 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 345 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 346 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 347 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 348 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 349 #elif defined (OpenBSD)
 350 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 351 #endif
 352
 353 #ifdef SC_REG_OFFSET
 354
 355   /* We only check the program counter, stack pointer and frame
 356      pointer since these members of `struct sigcontext' are essential
 357      for providing backtraces.  More checks could be added, but would
 358      involve adding configure checks for the appropriate structure
 359      members, since older BSD's don't provide all of them.  */
 360
 361 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 362 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 363 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 364
 365   /* Override the default value for the offset of the program counter
 366      in the sigcontext structure.  */
 367   offset = offsetof (struct sigcontext, sc_pc);
 368
 369   if (SC_PC_OFFSET != offset)
 370     {
 371       warning (_("\
 372 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 373 Please report this to <bug-gdb@gnu.org>."),
 374                offset, SC_PC_OFFSET);
 375     }
 376
 377   SC_PC_OFFSET = offset;
 378
 379   /* Likewise for the stack pointer.  */
 380   offset = offsetof (struct sigcontext, sc_sp);
 381
 382   if (SC_SP_OFFSET != offset)
 383     {
 384       warning (_("\
 385 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 386 Please report this to <bug-gdb@gnu.org>."),
 387                offset, SC_SP_OFFSET);
 388     }
 389
 390   SC_SP_OFFSET = offset;
 391
 392   /* And the frame pointer.  */
 393   offset = offsetof (struct sigcontext, sc_fp);
 394
 395   if (SC_FP_OFFSET != offset)
 396     {
 397       warning (_("\
 398 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 399 Please report this to <bug-gdb@gnu.org>."),
 400                offset, SC_FP_OFFSET);
 401     }
 402
 403   SC_FP_OFFSET = offset;
 404
 405 #endif /* SC_REG_OFFSET */
 406 }