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 <stddef.h>
  27 #include <sys/types.h>
  28 #include <sys/ptrace.h>
  29 #include <machine/reg.h>
  30 #include <machine/frame.h>
  31
  32 #include "i386-tdep.h"
  33 #include "i387-tdep.h"
  34 #include "i386bsd-nat.h"
  35 #include "inf-ptrace.h"
  36 \f
  37
  38 /* In older BSD versions we cannot get at some of the segment
  39    registers.  FreeBSD for example didn't support the %fs and %gs
  40    registers until the 3.0 release.  We have autoconf checks for their
  41    presence, and deal gracefully with their absence.  */
  42
  43 /* Offset in `struct reg' where MEMBER is stored.  */
  44 #define REG_OFFSET(member) offsetof (struct reg, member)
  45
  46 /* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct
  47    reg' where the GDB register REGNUM is stored.  Unsupported
  48    registers are marked with `-1'.  */
  49 static int i386bsd_r_reg_offset[] =
  50 {
  51   REG_OFFSET (r_eax),
  52   REG_OFFSET (r_ecx),
  53   REG_OFFSET (r_edx),
  54   REG_OFFSET (r_ebx),
  55   REG_OFFSET (r_esp),
  56   REG_OFFSET (r_ebp),
  57   REG_OFFSET (r_esi),
  58   REG_OFFSET (r_edi),
  59   REG_OFFSET (r_eip),
  60   REG_OFFSET (r_eflags),
  61   REG_OFFSET (r_cs),
  62   REG_OFFSET (r_ss),
  63   REG_OFFSET (r_ds),
  64   REG_OFFSET (r_es),
  65 #ifdef HAVE_STRUCT_REG_R_FS
  66   REG_OFFSET (r_fs),
  67 #else
  68   -1,
  69 #endif
  70 #ifdef HAVE_STRUCT_REG_R_GS
  71   REG_OFFSET (r_gs)
  72 #else
  73   -1
  74 #endif
  75 };
  76
  77 /* Macro to determine if a register is fetched with PT_GETREGS.  */
  78 #define GETREGS_SUPPLIES(regnum) \
  79   ((0 <= (regnum) && (regnum) <= 15))
  80
  81 #ifdef HAVE_PT_GETXMMREGS
  82 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
  83    so that we try PT_GETXMMREGS the first time around.  */
  84 static int have_ptrace_xmmregs = -1;
  85 #endif
  86 \f
  87
  88 /* Supply the general-purpose registers in GREGS, to REGCACHE.  */
  89
  90 static void
  91 i386bsd_supply_gregset (struct regcache *regcache, const void *gregs)
  92 {
  93   const char *regs = gregs;
  94   int regnum;
  95
  96   for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++)
  97     {
  98       int offset = i386bsd_r_reg_offset[regnum];
  99
 100       if (offset != -1)
 101         regcache_raw_supply (regcache, regnum, regs + offset);
 102     }
 103 }
 104
 105 /* Collect register REGNUM from REGCACHE and store its contents in
 106    GREGS.  If REGNUM is -1, collect and store all appropriate
 107    registers.  */
 108
 109 static void
 110 i386bsd_collect_gregset (const struct regcache *regcache,
 111                          void *gregs, int regnum)
 112 {
 113   char *regs = gregs;
 114   int i;
 115
 116   for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++)
 117     {
 118       if (regnum == -1 || regnum == i)
 119         {
 120           int offset = i386bsd_r_reg_offset[i];
 121
 122           if (offset != -1)
 123             regcache_raw_collect (regcache, i, regs + offset);
 124         }
 125     }
 126 }
 127
 128 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
 129    for all registers (including the floating point registers).  */
 130
 131 static void
 132 i386bsd_fetch_inferior_registers (struct target_ops *ops,
 133                                   struct regcache *regcache, int regnum)
 134 {
 135   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 136     {
 137       struct reg regs;
 138
 139       if (ptrace (PT_GETREGS, ptid_get_pid (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, ptid_get_pid (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, ptid_get_pid (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, ptid_get_pid (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 target_ops *ops,
 184                                   struct regcache *regcache, int regnum)
 185 {
 186   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 187     {
 188       struct reg regs;
 189
 190       if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
 191                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 192         perror_with_name (_("Couldn't get registers"));
 193
 194       i386bsd_collect_gregset (regcache, &regs, regnum);
 195
 196       if (ptrace (PT_SETREGS, ptid_get_pid (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, ptid_get_pid (inferior_ptid),
 212                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 213         {
 214           have_ptrace_xmmregs = 1;
 215
 216           i387_collect_fxsave (regcache, regnum, xmmregs);
 217
 218           if (ptrace (PT_SETXMMREGS, ptid_get_pid (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, ptid_get_pid (inferior_ptid),
 227                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 228             perror_with_name (_("Couldn't get floating point status"));
 229
 230           i387_collect_fsave (regcache, regnum, &fpregs);
 231
 232           if (ptrace (PT_SETFPREGS, ptid_get_pid (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 unsigned long
 267 i386bsd_dr_get (ptid_t ptid, int regnum)
 268 {
 269   struct dbreg dbregs;
 270
 271   if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
 272               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 273     perror_with_name (_("Couldn't read debug registers"));
 274
 275   return DBREG_DRX ((&dbregs), regnum);
 276 }
 277
 278 static void
 279 i386bsd_dr_set (int regnum, unsigned int value)
 280 {
 281   struct dbreg dbregs;
 282
 283   if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
 284               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 285     perror_with_name (_("Couldn't get debug registers"));
 286
 287   /* For some mysterious reason, some of the reserved bits in the
 288      debug control register get set.  Mask these off, otherwise the
 289      ptrace call below will fail.  */
 290   DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00);
 291
 292   DBREG_DRX ((&dbregs), regnum) = value;
 293
 294   if (ptrace (PT_SETDBREGS, ptid_get_pid (inferior_ptid),
 295               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
 296     perror_with_name (_("Couldn't write debug registers"));
 297 }
 298
 299 void
 300 i386bsd_dr_set_control (unsigned long control)
 301 {
 302   i386bsd_dr_set (7, control);
 303 }
 304
 305 void
 306 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 307 {
 308   gdb_assert (regnum >= 0 && regnum <= 4);
 309
 310   i386bsd_dr_set (regnum, addr);
 311 }
 312
 313 CORE_ADDR
 314 i386bsd_dr_get_addr (int regnum)
 315 {
 316   return i386bsd_dr_get (inferior_ptid, regnum);
 317 }
 318
 319 unsigned long
 320 i386bsd_dr_get_status (void)
 321 {
 322   return i386bsd_dr_get (inferior_ptid, 6);
 323 }
 324
 325 unsigned long
 326 i386bsd_dr_get_control (void)
 327 {
 328   return i386bsd_dr_get (inferior_ptid, 7);
 329 }
 330
 331 #endif /* PT_GETDBREGS */
 332 \f
 333
 334 /* Provide a prototype to silence -Wmissing-prototypes.  */
 335 void _initialize_i386bsd_nat (void);
 336
 337 void
 338 _initialize_i386bsd_nat (void)
 339 {
 340   int offset;
 341
 342   /* To support the recognition of signal handlers, i386bsd-tdep.c
 343      hardcodes some constants.  Inclusion of this file means that we
 344      are compiling a native debugger, which means that we can use the
 345      system header files and sysctl(3) to get at the relevant
 346      information.  */
 347
 348 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 349 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 350 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 351 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 352 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 353 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 354 #elif defined (OpenBSD)
 355 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 356 #endif
 357
 358 #ifdef SC_REG_OFFSET
 359
 360   /* We only check the program counter, stack pointer and frame
 361      pointer since these members of `struct sigcontext' are essential
 362      for providing backtraces.  More checks could be added, but would
 363      involve adding configure checks for the appropriate structure
 364      members, since older BSD's don't provide all of them.  */
 365
 366 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 367 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 368 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 369
 370   /* Override the default value for the offset of the program counter
 371      in the sigcontext structure.  */
 372   offset = offsetof (struct sigcontext, sc_pc);
 373
 374   if (SC_PC_OFFSET != offset)
 375     {
 376       warning (_("\
 377 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 378 Please report this to <bug-gdb@gnu.org>."),
 379                offset, SC_PC_OFFSET);
 380     }
 381
 382   SC_PC_OFFSET = offset;
 383
 384   /* Likewise for the stack pointer.  */
 385   offset = offsetof (struct sigcontext, sc_sp);
 386
 387   if (SC_SP_OFFSET != offset)
 388     {
 389       warning (_("\
 390 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 391 Please report this to <bug-gdb@gnu.org>."),
 392                offset, SC_SP_OFFSET);
 393     }
 394
 395   SC_SP_OFFSET = offset;
 396
 397   /* And the frame pointer.  */
 398   offset = offsetof (struct sigcontext, sc_fp);
 399
 400   if (SC_FP_OFFSET != offset)
 401     {
 402       warning (_("\
 403 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 404 Please report this to <bug-gdb@gnu.org>."),
 405                offset, SC_FP_OFFSET);
 406     }
 407
 408   SC_FP_OFFSET = offset;
 409
 410 #endif /* SC_REG_OFFSET */
 411 }