gdb/i386-bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2
   3    Copyright (C) 2000-2019 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 "x86-bsd-nat.h"
  33 #include "i386-bsd-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 (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 (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 void
 131 i386bsd_fetch_inferior_registers (struct regcache *regcache, int regnum)
 132 {
 133   pid_t pid = get_ptrace_pid (regcache->ptid ());
 134
 135   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 136     {
 137       struct reg regs;
 138
 139       if (ptrace (PT_GETREGS, pid, (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, pid,
 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, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 172         {
 173           have_ptrace_xmmregs = 1;
 174           i387_supply_fxsave (regcache, -1, xmmregs);
 175         }
 176       else
 177         {
 178           have_ptrace_xmmregs = 0;
 179 #endif
 180           if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 181             perror_with_name (_("Couldn't get floating point status"));
 182
 183           i387_supply_fsave (regcache, -1, &fpregs);
 184 #ifdef HAVE_PT_GETXMMREGS
 185         }
 186 #endif
 187     }
 188 }
 189
 190 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 191    this for all registers (including the floating point registers).  */
 192
 193 void
 194 i386bsd_store_inferior_registers (struct regcache *regcache, int regnum)
 195 {
 196   pid_t pid = get_ptrace_pid (regcache->ptid ());
 197
 198   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 199     {
 200       struct reg regs;
 201
 202       if (ptrace (PT_GETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 203         perror_with_name (_("Couldn't get registers"));
 204
 205       i386bsd_collect_gregset (regcache, &regs, regnum);
 206
 207       if (ptrace (PT_SETREGS, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 208         perror_with_name (_("Couldn't write registers"));
 209
 210       if (regnum != -1)
 211         return;
 212     }
 213
 214   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 215     {
 216       struct fpreg fpregs;
 217 #ifdef HAVE_PT_GETXMMREGS
 218       char xmmregs[512];
 219 #endif
 220
 221 #ifdef PT_GETXSTATE_INFO
 222       if (x86bsd_xsave_len != 0)
 223         {
 224           void *xstateregs;
 225
 226           xstateregs = alloca (x86bsd_xsave_len);
 227           if (ptrace (PT_GETXSTATE, pid,
 228                       (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 229             perror_with_name (_("Couldn't get extended state status"));
 230
 231           i387_collect_xsave (regcache, -1, xstateregs, 0);
 232
 233           if (ptrace (PT_SETXSTATE, pid,
 234                       (PTRACE_TYPE_ARG3) xstateregs, x86bsd_xsave_len) == -1)
 235             perror_with_name (_("Couldn't write extended state status"));
 236           return;
 237         }
 238 #endif
 239
 240 #ifdef HAVE_PT_GETXMMREGS
 241       if (have_ptrace_xmmregs != 0
 242           && ptrace(PT_GETXMMREGS, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 243         {
 244           have_ptrace_xmmregs = 1;
 245
 246           i387_collect_fxsave (regcache, regnum, xmmregs);
 247
 248           if (ptrace (PT_SETXMMREGS, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
 249             perror_with_name (_("Couldn't write XMM registers"));
 250         }
 251       else
 252         {
 253           have_ptrace_xmmregs = 0;
 254 #endif
 255           if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 256             perror_with_name (_("Couldn't get floating point status"));
 257
 258           i387_collect_fsave (regcache, regnum, &fpregs);
 259
 260           if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 261             perror_with_name (_("Couldn't write floating point status"));
 262 #ifdef HAVE_PT_GETXMMREGS
 263         }
 264 #endif
 265     }
 266 }
 267
 268 void
 269 _initialize_i386bsd_nat (void)
 270 {
 271   int offset;
 272
 273   /* To support the recognition of signal handlers, i386-bsd-tdep.c
 274      hardcodes some constants.  Inclusion of this file means that we
 275      are compiling a native debugger, which means that we can use the
 276      system header files and sysctl(3) to get at the relevant
 277      information.  */
 278
 279 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 280 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 281 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 282 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 283 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 284 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 285 #elif defined (OpenBSD)
 286 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 287 #endif
 288
 289 #ifdef SC_REG_OFFSET
 290
 291   /* We only check the program counter, stack pointer and frame
 292      pointer since these members of `struct sigcontext' are essential
 293      for providing backtraces.  More checks could be added, but would
 294      involve adding configure checks for the appropriate structure
 295      members, since older BSD's don't provide all of them.  */
 296
 297 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 298 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 299 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 300
 301   /* Override the default value for the offset of the program counter
 302      in the sigcontext structure.  */
 303   offset = offsetof (struct sigcontext, sc_pc);
 304
 305   if (SC_PC_OFFSET != offset)
 306     {
 307       warning (_("\
 308 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 309 Please report this to <bug-gdb@gnu.org>."),
 310                offset, SC_PC_OFFSET);
 311     }
 312
 313   SC_PC_OFFSET = offset;
 314
 315   /* Likewise for the stack pointer.  */
 316   offset = offsetof (struct sigcontext, sc_sp);
 317
 318   if (SC_SP_OFFSET != offset)
 319     {
 320       warning (_("\
 321 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 322 Please report this to <bug-gdb@gnu.org>."),
 323                offset, SC_SP_OFFSET);
 324     }
 325
 326   SC_SP_OFFSET = offset;
 327
 328   /* And the frame pointer.  */
 329   offset = offsetof (struct sigcontext, sc_fp);
 330
 331   if (SC_FP_OFFSET != offset)
 332     {
 333       warning (_("\
 334 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 335 Please report this to <bug-gdb@gnu.org>."),
 336                offset, SC_FP_OFFSET);
 337     }
 338
 339   SC_FP_OFFSET = offset;
 340
 341 #endif /* SC_REG_OFFSET */
 342 }