gdb/i386-bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2
   3    Copyright (C) 2000-2018 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 (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   pid_t pid = get_ptrace_pid (regcache_get_ptid (regcache));
 135
 136   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 137     {
 138       struct reg regs;
 139
 140       if (ptrace (PT_GETREGS, pid, (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 #endif
 154
 155 #ifdef PT_GETXSTATE_INFO
 156       if (x86bsd_xsave_len != 0)
 157         {
 158           void *xstateregs;
 159
 160           xstateregs = alloca (x86bsd_xsave_len);
 161           if (ptrace (PT_GETXSTATE, pid,
 162                       (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 163             perror_with_name (_("Couldn't get extended state status"));
 164
 165           i387_supply_xsave (regcache, -1, xstateregs);
 166           return;
 167         }
 168 #endif
 169
 170 #ifdef HAVE_PT_GETXMMREGS
 171       if (have_ptrace_xmmregs != 0
 172           && ptrace(PT_GETXMMREGS, pid, (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, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 182             perror_with_name (_("Couldn't get floating point status"));
 183
 184           i387_supply_fsave (regcache, -1, &fpregs);
 185 #ifdef HAVE_PT_GETXMMREGS
 186         }
 187 #endif
 188     }
 189 }
 190
 191 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 192    this for all registers (including the floating point registers).  */
 193
 194 static void
 195 i386bsd_store_inferior_registers (struct target_ops *ops,
 196                                   struct regcache *regcache, int regnum)
 197 {
 198   pid_t pid = get_ptrace_pid (regcache_get_ptid (regcache));
 199
 200   if (regnum == -1 || GETREGS_SUPPLIES (regnum))
 201     {
 202       struct reg regs;
 203
 204       if (ptrace (PT_GETREGS, pid, (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, pid, (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 210         perror_with_name (_("Couldn't write registers"));
 211
 212       if (regnum != -1)
 213         return;
 214     }
 215
 216   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
 217     {
 218       struct fpreg fpregs;
 219 #ifdef HAVE_PT_GETXMMREGS
 220       char xmmregs[512];
 221 #endif
 222
 223 #ifdef PT_GETXSTATE_INFO
 224       if (x86bsd_xsave_len != 0)
 225         {
 226           void *xstateregs;
 227
 228           xstateregs = alloca (x86bsd_xsave_len);
 229           if (ptrace (PT_GETXSTATE, pid,
 230                       (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 231             perror_with_name (_("Couldn't get extended state status"));
 232
 233           i387_collect_xsave (regcache, -1, xstateregs, 0);
 234
 235           if (ptrace (PT_SETXSTATE, pid,
 236                       (PTRACE_TYPE_ARG3) xstateregs, x86bsd_xsave_len) == -1)
 237             perror_with_name (_("Couldn't write extended state status"));
 238           return;
 239         }
 240 #endif
 241
 242 #ifdef HAVE_PT_GETXMMREGS
 243       if (have_ptrace_xmmregs != 0
 244           && ptrace(PT_GETXMMREGS, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 245         {
 246           have_ptrace_xmmregs = 1;
 247
 248           i387_collect_fxsave (regcache, regnum, xmmregs);
 249
 250           if (ptrace (PT_SETXMMREGS, pid, (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
 251             perror_with_name (_("Couldn't write XMM registers"));
 252         }
 253       else
 254         {
 255           have_ptrace_xmmregs = 0;
 256 #endif
 257           if (ptrace (PT_GETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 258             perror_with_name (_("Couldn't get floating point status"));
 259
 260           i387_collect_fsave (regcache, regnum, &fpregs);
 261
 262           if (ptrace (PT_SETFPREGS, pid, (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 263             perror_with_name (_("Couldn't write floating point status"));
 264 #ifdef HAVE_PT_GETXMMREGS
 265         }
 266 #endif
 267     }
 268 }
 269
 270 /* Create a prototype *BSD/i386 target.  The client can override it
 271    with local methods.  */
 272
 273 struct target_ops *
 274 i386bsd_target (void)
 275 {
 276   struct target_ops *t;
 277
 278   t = x86bsd_target ();
 279   t->to_fetch_registers = i386bsd_fetch_inferior_registers;
 280   t->to_store_registers = i386bsd_store_inferior_registers;
 281   return t;
 282 }
 283
 284 void
 285 _initialize_i386bsd_nat (void)
 286 {
 287   int offset;
 288
 289   /* To support the recognition of signal handlers, i386-bsd-tdep.c
 290      hardcodes some constants.  Inclusion of this file means that we
 291      are compiling a native debugger, which means that we can use the
 292      system header files and sysctl(3) to get at the relevant
 293      information.  */
 294
 295 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011
 296 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset
 297 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005
 298 #define SC_REG_OFFSET i386fbsd_sc_reg_offset
 299 #elif defined (NetBSD) || defined (__NetBSD_Version__)
 300 #define SC_REG_OFFSET i386nbsd_sc_reg_offset
 301 #elif defined (OpenBSD)
 302 #define SC_REG_OFFSET i386obsd_sc_reg_offset
 303 #endif
 304
 305 #ifdef SC_REG_OFFSET
 306
 307   /* We only check the program counter, stack pointer and frame
 308      pointer since these members of `struct sigcontext' are essential
 309      for providing backtraces.  More checks could be added, but would
 310      involve adding configure checks for the appropriate structure
 311      members, since older BSD's don't provide all of them.  */
 312
 313 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM]
 314 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM]
 315 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM]
 316
 317   /* Override the default value for the offset of the program counter
 318      in the sigcontext structure.  */
 319   offset = offsetof (struct sigcontext, sc_pc);
 320
 321   if (SC_PC_OFFSET != offset)
 322     {
 323       warning (_("\
 324 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\
 325 Please report this to <bug-gdb@gnu.org>."),
 326                offset, SC_PC_OFFSET);
 327     }
 328
 329   SC_PC_OFFSET = offset;
 330
 331   /* Likewise for the stack pointer.  */
 332   offset = offsetof (struct sigcontext, sc_sp);
 333
 334   if (SC_SP_OFFSET != offset)
 335     {
 336       warning (_("\
 337 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\
 338 Please report this to <bug-gdb@gnu.org>."),
 339                offset, SC_SP_OFFSET);
 340     }
 341
 342   SC_SP_OFFSET = offset;
 343
 344   /* And the frame pointer.  */
 345   offset = offsetof (struct sigcontext, sc_fp);
 346
 347   if (SC_FP_OFFSET != offset)
 348     {
 349       warning (_("\
 350 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\
 351 Please report this to <bug-gdb@gnu.org>."),
 352                offset, SC_FP_OFFSET);
 353     }
 354
 355   SC_FP_OFFSET = offset;
 356
 357 #endif /* SC_REG_OFFSET */
 358 }