gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2
   3    Copyright (C) 2000-2014 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 3 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, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "inferior.h"
  22 #include "regcache.h"
  23
  24 #include "gdb_assert.h"
  25 #include <signal.h>
  26 #include <sys/types.h>
  27 #include <sys/ptrace.h>
  28 #include <machine/reg.h>
  29 #include <machine/frame.h>
  30
  31 #include "i386-tdep.h"
  32 #include "i387-tdep.h"
  33 #include "i386bsd-nat.h"
  34 #include "inf-ptrace.h"
  35 \f
  36
  37 /* In older BSD versions we cannot get at some of the segment
  38    registers.  FreeBSD for example didn't support the %fs and %gs
  39    registers until the 3.0 release.  We have autoconf checks for their
  40    presence, and deal gracefully with their absence.  */
  41
  42 /* Offset in `struct reg' where MEMBER is stored.  */
  43 #define REG_OFFSET(member) offsetof (struct reg, member)
  44
  45 /* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct
  46    reg' where the GDB register REGNUM is stored.  Unsupported
  47    registers are marked with `-1'.  */
  48 static int i386bsd_r_reg_offset[] =
  49 {
  50   REG_OFFSET (r_eax),
  51   REG_OFFSET (r_ecx),
  52   REG_OFFSET (r_edx),
  53   REG_OFFSET (r_ebx),
  54   REG_OFFSET (r_esp),
  55   REG_OFFSET (r_ebp),
  56   REG_OFFSET (r_esi),
  57   REG_OFFSET (r_edi),
  58   REG_OFFSET (r_eip),
  59   REG_OFFSET (r_eflags),
  60   REG_OFFSET (r_cs),
  61   REG_OFFSET (r_ss),
  62   REG_OFFSET (r_ds),
  63   REG_OFFSET (r_es),
  64 #ifdef HAVE_STRUCT_REG_R_FS
  65   REG_OFFSET (r_fs),
  66 #else
  67   -1,
  68 #endif
  69 #ifdef HAVE_STRUCT_REG_R_GS
  70   REG_OFFSET (r_gs)
  71 #else
  72   -1
  73 #endif
  74 };
  75
  76 /* Macro to determine if a register is fetched with PT_GETREGS.  */
  77 #define GETREGS_SUPPLIES(regnum) \
  78   ((0 <= (regnum) && (regnum) <= 15))
  79
  80 #ifdef HAVE_PT_GETXMMREGS
  81 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
  82    so that we try PT_GETXMMREGS the first time around.  */
  83 static int have_ptrace_xmmregs = -1;
  84 #endif
  85 \f
  86
  87 /* Supply the general-purpose registers in GREGS, to REGCACHE.  */
  88
  89 static void
  90 i386bsd_supply_gregset (struct regcache *regcache, const void *gregs)
  91 {
  92   const char *regs = gregs;
  93   int regnum;
  94
  95   for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++)
  96     {
  97       int offset = i386bsd_r_reg_offset[regnum];
  98
  99       if (offset != -1)
 100         regcache_raw_supply (regcache, regnum, regs + offset);
 101     }
 102 }
 103
 104 /* Collect register REGNUM from REGCACHE and store its contents in
 105    GREGS.  If REGNUM is -1, collect and store all appropriate
 106    registers.  */
 107
 108 static void
 109 i386bsd_collect_gregset (const struct regcache *regcache,
 110                          void *gregs, int regnum)
 111 {
 112   char *regs = gregs;
 113   int i;
 114
 115   for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++)
 116     {
 117       if (regnum == -1 || regnum == i)
 118         {
 119           int offset = i386bsd_r_reg_offset[i];
 120
 121           if (offset != -1)
 122             regcache_raw_collect (regcache, i, regs + offset);
 123         }
 124     }
 125 }
 126
 127 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 128    for all registers (including the floating point registers).  */
 129
 130 static void
 131 i386bsd_fetch_inferior_registers (struct target_ops *ops,
 132                                   struct regcache *regcache, int regnum)
 133 {
 134   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 135     {
 136       struct reg regs;
 137
 138       if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
 139                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 140         perror_with_name (_("Couldn't get registers"));
 141
 142       i386bsd_supply_gregset (regcache, &regs);
 143       if (regnum != -1)
 144         return;
 145     }
 146
 147   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 148     {
 149       struct fpreg fpregs;
 150 #ifdef HAVE_PT_GETXMMREGS
 151       char xmmregs[512];
 152
 153       if (have_ptrace_xmmregs != 0
 154           && ptrace(PT_GETXMMREGS, ptid_get_pid (inferior_ptid),
 155                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 156         {
 157           have_ptrace_xmmregs = 1;
 158           i387_supply_fxsave (regcache, -1, xmmregs);
 159         }
 160       else
 161         {
 162           if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
 163                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 164             perror_with_name (_("Couldn't get floating point status"));
 165
 166           i387_supply_fsave (regcache, -1, &fpregs);
 167         }
 168 #else
 169       if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
 170                   (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 171         perror_with_name (_("Couldn't get floating point status"));
 172
 173       i387_supply_fsave (regcache, -1, &fpregs);
 174 #endif
 175     }
 176 }
 177
 178 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 179    this for all registers (including the floating point registers).  */
 180
 181 static void
 182 i386bsd_store_inferior_registers (struct target_ops *ops,
 183                                   struct regcache *regcache, int regnum)
 184 {
 185   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 186     {
 187       struct reg regs;
 188
 189       if (ptrace (PT_GETREGS, ptid_get_pid (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, ptid_get_pid (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, ptid_get_pid (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, ptid_get_pid (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, ptid_get_pid (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, ptid_get_pid (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 unsigned long
 266 i386bsd_dr_get (ptid_t ptid, int regnum)
 267 {
 268   struct dbreg dbregs;
 269
 270   if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
 271               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 272     perror_with_name (_("Couldn't read debug registers"));
 273
 274   return DBREG_DRX ((&dbregs), regnum);
 275 }
 276
 277 static void
 278 i386bsd_dr_set (int regnum, unsigned int value)
 279 {
 280   struct dbreg dbregs;
 281
 282   if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
 283               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 284     perror_with_name (_("Couldn't get debug registers"));
 285
 286   /* For some mysterious reason, some of the reserved bits in the
 287      debug control register get set.  Mask these off, otherwise the
 288      ptrace call below will fail.  */
 289   DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
 290
 291   DBREG_DRX ((&dbregs), regnum) = value;
 292
 293   if (ptrace (PT_SETDBREGS, ptid_get_pid (inferior_ptid),
 294               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 295     perror_with_name (_("Couldn't write debug registers"));
 296 }
 297
 298 void
 299 i386bsd_dr_set_control (unsigned long control)
 300 {
 301   i386bsd_dr_set (7, control);
 302 }
 303
 304 void
 305 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 306 {
 307   gdb_assert (regnum >= 0 && regnum <= 4);
 308
 309   i386bsd_dr_set (regnum, addr);
 310 }
 311
 312 CORE_ADDR
 313 i386bsd_dr_get_addr (int regnum)
 314 {
 315   return i386bsd_dr_get (inferior_ptid, regnum);
 316 }
 317
 318 unsigned long
 319 i386bsd_dr_get_status (void)
 320 {
 321   return i386bsd_dr_get (inferior_ptid, 6);
 322 }
 323
 324 unsigned long
 325 i386bsd_dr_get_control (void)
 326 {
 327   return i386bsd_dr_get (inferior_ptid, 7);
 328 }
 329
 330 #endif /* PT_GETDBREGS */
 331 \f
 332
 333 /* Provide a prototype to silence -Wmissing-prototypes.  */
 334 void _initialize_i386bsd_nat (void);
 335
 336 void
 337 _initialize_i386bsd_nat (void)
 338 {
 339   int offset;
 340
 341   /* To support the recognition of signal handlers, i386bsd-tdep.c
 342      hardcodes some constants.  Inclusion of this file means that we
 343      are compiling a native debugger, which means that we can use the
 344      system header files and sysctl(3) to get at the relevant
 345      information.  */
 346
 347 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 348 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 349 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 350 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 351 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 352 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 353 #elif defined (OpenBSD)
 354 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 355 #endif
 356
 357 #ifdef SC_REG_OFFSET
 358
 359   /* We only check the program counter, stack pointer and frame
 360      pointer since these members of `struct sigcontext' are essential
 361      for providing backtraces.  More checks could be added, but would
 362      involve adding configure checks for the appropriate structure
 363      members, since older BSD's don't provide all of them.  */
 364
 365 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 366 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 367 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 368
 369   /* Override the default value for the offset of the program counter
 370      in the sigcontext structure.  */
 371   offset = offsetof (struct sigcontext, sc_pc);
 372
 373   if (SC_PC_OFFSET != offset)
 374     {
 375       warning (_("\
 376 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 377 Please report this to <bug-gdb@gnu.org>."),
 378                offset, SC_PC_OFFSET);
 379     }
 380
 381   SC_PC_OFFSET = offset;
 382
 383   /* Likewise for the stack pointer.  */
 384   offset = offsetof (struct sigcontext, sc_sp);
 385
 386   if (SC_SP_OFFSET != offset)
 387     {
 388       warning (_("\
 389 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 390 Please report this to <bug-gdb@gnu.org>."),
 391                offset, SC_SP_OFFSET);
 392     }
 393
 394   SC_SP_OFFSET = offset;
 395
 396   /* And the frame pointer.  */
 397   offset = offsetof (struct sigcontext, sc_fp);
 398
 399   if (SC_FP_OFFSET != offset)
 400     {
 401       warning (_("\
 402 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 403 Please report this to <bug-gdb@gnu.org>."),
 404                offset, SC_FP_OFFSET);
 405     }
 406
 407   SC_FP_OFFSET = offset;
 408
 409 #endif /* SC_REG_OFFSET */
 410 }