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, 2009, 2010
   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 target_ops *ops,
 134                                   struct regcache *regcache, 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 (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 (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 (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 (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 (struct target_ops *ops,
 185                                   struct regcache *regcache, int regnum)
 186 {
 187   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 188     {
 189       struct reg regs;
 190
 191       if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 192                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 193         perror_with_name (_("Couldn't get registers"));
 194
 195       i386bsd_collect_gregset (regcache, &regs, regnum);
 196
 197       if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 198                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 199         perror_with_name (_("Couldn't write registers"));
 200
 201       if (regnum != -1)
 202         return;
 203     }
 204
 205   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 206     {
 207       struct fpreg fpregs;
 208 #ifdef HAVE_PT_GETXMMREGS
 209       char xmmregs[512];
 210
 211       if (have_ptrace_xmmregs != 0
 212           && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid),
 213                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 214         {
 215           have_ptrace_xmmregs = 1;
 216
 217           i387_collect_fxsave (regcache, regnum, xmmregs);
 218
 219           if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid),
 220                       (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
 221             perror_with_name (_("Couldn't write XMM registers"));
 222         }
 223       else
 224         {
 225           have_ptrace_xmmregs = 0;
 226 #endif
 227           if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 228                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 229             perror_with_name (_("Couldn't get floating point status"));
 230
 231           i387_collect_fsave (regcache, regnum, &fpregs);
 232
 233           if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 234                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 235             perror_with_name (_("Couldn't write floating point status"));
 236 #ifdef HAVE_PT_GETXMMREGS
 237         }
 238 #endif
 239     }
 240 }
 241
 242 /* Create a prototype *BSD/i386 target.  The client can override it
 243    with local methods.  */
 244
 245 struct target_ops *
 246 i386bsd_target (void)
 247 {
 248   struct target_ops *t;
 249
 250   t = inf_ptrace_target ();
 251   t->to_fetch_registers = i386bsd_fetch_inferior_registers;
 252   t->to_store_registers = i386bsd_store_inferior_registers;
 253   return t;
 254 }
 255 \f
 256
 257 /* Support for debug registers.  */
 258
 259 #ifdef HAVE_PT_GETDBREGS
 260
 261 /* Not all versions of FreeBSD/i386 that support the debug registers
 262    have this macro.  */
 263 #ifndef DBREG_DRX
 264 #define DBREG_DRX(d, x) ((&d->dr0)[x])
 265 #endif
 266
 267 static void
 268 i386bsd_dr_set (int regnum, unsigned int value)
 269 {
 270   struct dbreg dbregs;
 271
 272   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 273               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 274     perror_with_name (_("Couldn't get debug registers"));
 275
 276   /* For some mysterious reason, some of the reserved bits in the
 277      debug control register get set.  Mask these off, otherwise the
 278      ptrace call below will fail.  */
 279   DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
 280
 281   DBREG_DRX ((&dbregs), regnum) = value;
 282
 283   if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
 284               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 285     perror_with_name (_("Couldn't write debug registers"));
 286 }
 287
 288 void
 289 i386bsd_dr_set_control (unsigned long control)
 290 {
 291   i386bsd_dr_set (7, control);
 292 }
 293
 294 void
 295 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 296 {
 297   gdb_assert (regnum >= 0 && regnum <= 4);
 298
 299   i386bsd_dr_set (regnum, addr);
 300 }
 301
 302 void
 303 i386bsd_dr_reset_addr (int regnum)
 304 {
 305   gdb_assert (regnum >= 0 && regnum <= 4);
 306
 307   i386bsd_dr_set (regnum, 0);
 308 }
 309
 310 unsigned long
 311 i386bsd_dr_get_status (void)
 312 {
 313   struct dbreg dbregs;
 314
 315   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
 316      ptrace call fails breaks debugging remote targets.  The correct
 317      way to fix this is to add the hardware breakpoint and watchpoint
 318      stuff to the target vector.  For now, just return zero if the
 319      ptrace call fails.  */
 320   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 321               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 322 #if 0
 323     perror_with_name (_("Couldn't read debug registers"));
 324 #else
 325     return 0;
 326 #endif
 327
 328   return DBREG_DRX ((&dbregs), 6);
 329 }
 330
 331 #endif /* PT_GETDBREGS */
 332 \f
 333
 334 void
 335 _initialize_i386bsd_nat (void)
 336 {
 337   int offset;
 338
 339   /* To support the recognition of signal handlers, i386bsd-tdep.c
 340      hardcodes some constants.  Inclusion of this file means that we
 341      are compiling a native debugger, which means that we can use the
 342      system header files and sysctl(3) to get at the relevant
 343      information.  */
 344
 345 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 346 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 347 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 348 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 349 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 350 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 351 #elif defined (OpenBSD)
 352 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 353 #endif
 354
 355 #ifdef SC_REG_OFFSET
 356
 357   /* We only check the program counter, stack pointer and frame
 358      pointer since these members of `struct sigcontext' are essential
 359      for providing backtraces.  More checks could be added, but would
 360      involve adding configure checks for the appropriate structure
 361      members, since older BSD's don't provide all of them.  */
 362
 363 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 364 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 365 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 366
 367   /* Override the default value for the offset of the program counter
 368      in the sigcontext structure.  */
 369   offset = offsetof (struct sigcontext, sc_pc);
 370
 371   if (SC_PC_OFFSET != offset)
 372     {
 373       warning (_("\
 374 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 375 Please report this to <bug-gdb@gnu.org>."),
 376                offset, SC_PC_OFFSET);
 377     }
 378
 379   SC_PC_OFFSET = offset;
 380
 381   /* Likewise for the stack pointer.  */
 382   offset = offsetof (struct sigcontext, sc_sp);
 383
 384   if (SC_SP_OFFSET != offset)
 385     {
 386       warning (_("\
 387 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 388 Please report this to <bug-gdb@gnu.org>."),
 389                offset, SC_SP_OFFSET);
 390     }
 391
 392   SC_SP_OFFSET = offset;
 393
 394   /* And the frame pointer.  */
 395   offset = offsetof (struct sigcontext, sc_fp);
 396
 397   if (SC_FP_OFFSET != offset)
 398     {
 399       warning (_("\
 400 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 401 Please report this to <bug-gdb@gnu.org>."),
 402                offset, SC_FP_OFFSET);
 403     }
 404
 405   SC_FP_OFFSET = offset;
 406
 407 #endif /* SC_REG_OFFSET */
 408 }