gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2
   3    Copyright (C) 2000-2016 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 <signal.h>
  25 #include <sys/types.h>
  26 #include <sys/ptrace.h>
  27 #include <machine/reg.h>
  28 #include <machine/frame.h>
  29
  30 #include "i386-tdep.h"
  31 #include "i387-tdep.h"
  32 #include "x86bsd-nat.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 = (const char *) 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 = (char *) 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, get_ptrace_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 #endif
 153
 154 #ifdef PT_GETXSTATE_INFO
 155       if (x86bsd_xsave_len != 0)
 156         {
 157           void *xstateregs;
 158
 159           xstateregs = alloca (x86bsd_xsave_len);
 160           if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 161                       (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 162             perror_with_name (_("Couldn't get extended state status"));
 163
 164           i387_supply_xsave (regcache, -1, xstateregs);
 165           return;
 166         }
 167 #endif
 168
 169 #ifdef HAVE_PT_GETXMMREGS
 170       if (have_ptrace_xmmregs != 0
 171           && ptrace(PT_GETXMMREGS, get_ptrace_pid (inferior_ptid),
 172                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 173         {
 174           have_ptrace_xmmregs = 1;
 175           i387_supply_fxsave (regcache, -1, xmmregs);
 176         }
 177       else
 178         {
 179           have_ptrace_xmmregs = 0;
 180 #endif
 181           if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 182                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 183             perror_with_name (_("Couldn't get floating point status"));
 184
 185           i387_supply_fsave (regcache, -1, &fpregs);
 186 #ifdef HAVE_PT_GETXMMREGS
 187         }
 188 #endif
 189     }
 190 }
 191
 192 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 193    this for all registers (including the floating point registers).  */
 194
 195 static void
 196 i386bsd_store_inferior_registers (struct target_ops *ops,
 197                                   struct regcache *regcache, int regnum)
 198 {
 199   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 200     {
 201       struct reg regs;
 202
 203       if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
 204                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 205         perror_with_name (_("Couldn't get registers"));
 206
 207       i386bsd_collect_gregset (regcache, &regs, regnum);
 208
 209       if (ptrace (PT_SETREGS, get_ptrace_pid (inferior_ptid),
 210                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 211         perror_with_name (_("Couldn't write registers"));
 212
 213       if (regnum != -1)
 214         return;
 215     }
 216
 217   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 218     {
 219       struct fpreg fpregs;
 220 #ifdef HAVE_PT_GETXMMREGS
 221       char xmmregs[512];
 222 #endif
 223
 224 #ifdef PT_GETXSTATE_INFO
 225       if (x86bsd_xsave_len != 0)
 226         {
 227           void *xstateregs;
 228
 229           xstateregs = alloca (x86bsd_xsave_len);
 230           if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 231                       (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 232             perror_with_name (_("Couldn't get extended state status"));
 233
 234           i387_collect_xsave (regcache, -1, xstateregs, 0);
 235
 236           if (ptrace (PT_SETXSTATE, get_ptrace_pid (inferior_ptid),
 237                       (PTRACE_TYPE_ARG3) xstateregs, x86bsd_xsave_len) == -1)
 238             perror_with_name (_("Couldn't write extended state status"));
 239           return;
 240         }
 241 #endif
 242
 243 #ifdef HAVE_PT_GETXMMREGS
 244       if (have_ptrace_xmmregs != 0
 245           && ptrace(PT_GETXMMREGS, get_ptrace_pid (inferior_ptid),
 246                     (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 247         {
 248           have_ptrace_xmmregs = 1;
 249
 250           i387_collect_fxsave (regcache, regnum, xmmregs);
 251
 252           if (ptrace (PT_SETXMMREGS, get_ptrace_pid (inferior_ptid),
 253                       (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
 254             perror_with_name (_("Couldn't write XMM registers"));
 255         }
 256       else
 257         {
 258           have_ptrace_xmmregs = 0;
 259 #endif
 260           if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 261                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 262             perror_with_name (_("Couldn't get floating point status"));
 263
 264           i387_collect_fsave (regcache, regnum, &fpregs);
 265
 266           if (ptrace (PT_SETFPREGS, get_ptrace_pid (inferior_ptid),
 267                       (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 268             perror_with_name (_("Couldn't write floating point status"));
 269 #ifdef HAVE_PT_GETXMMREGS
 270         }
 271 #endif
 272     }
 273 }
 274
 275 /* Create a prototype *BSD/i386 target.  The client can override it
 276    with local methods.  */
 277
 278 struct target_ops *
 279 i386bsd_target (void)
 280 {
 281   struct target_ops *t;
 282
 283   t = x86bsd_target ();
 284   t->to_fetch_registers = i386bsd_fetch_inferior_registers;
 285   t->to_store_registers = i386bsd_store_inferior_registers;
 286   return t;
 287 }
 288 \f
 289
 290 /* Provide a prototype to silence -Wmissing-prototypes.  */
 291 void _initialize_i386bsd_nat (void);
 292
 293 void
 294 _initialize_i386bsd_nat (void)
 295 {
 296   int offset;
 297
 298   /* To support the recognition of signal handlers, i386bsd-tdep.c
 299      hardcodes some constants.  Inclusion of this file means that we
 300      are compiling a native debugger, which means that we can use the
 301      system header files and sysctl(3) to get at the relevant
 302      information.  */
 303
 304 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 305 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 306 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 307 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 308 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 309 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 310 #elif defined (OpenBSD)
 311 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 312 #endif
 313
 314 #ifdef SC_REG_OFFSET
 315
 316   /* We only check the program counter, stack pointer and frame
 317      pointer since these members of `struct sigcontext' are essential
 318      for providing backtraces.  More checks could be added, but would
 319      involve adding configure checks for the appropriate structure
 320      members, since older BSD's don't provide all of them.  */
 321
 322 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 323 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 324 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 325
 326   /* Override the default value for the offset of the program counter
 327      in the sigcontext structure.  */
 328   offset = offsetof (struct sigcontext, sc_pc);
 329
 330   if (SC_PC_OFFSET != offset)
 331     {
 332       warning (_("\
 333 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 334 Please report this to <bug-gdb@gnu.org>."),
 335                offset, SC_PC_OFFSET);
 336     }
 337
 338   SC_PC_OFFSET = offset;
 339
 340   /* Likewise for the stack pointer.  */
 341   offset = offsetof (struct sigcontext, sc_sp);
 342
 343   if (SC_SP_OFFSET != offset)
 344     {
 345       warning (_("\
 346 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 347 Please report this to <bug-gdb@gnu.org>."),
 348                offset, SC_SP_OFFSET);
 349     }
 350
 351   SC_SP_OFFSET = offset;
 352
 353   /* And the frame pointer.  */
 354   offset = offsetof (struct sigcontext, sc_fp);
 355
 356   if (SC_FP_OFFSET != offset)
 357     {
 358       warning (_("\
 359 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 360 Please report this to <bug-gdb@gnu.org>."),
 361                offset, SC_FP_OFFSET);
 362     }
 363
 364   SC_FP_OFFSET = offset;
 365
 366 #endif /* SC_REG_OFFSET */
 367 }