gdb/amd64-linux-nat.c

   1 /* Native-dependent code for GNU/Linux x86-64.
   2
   3    Copyright (C) 2001-2017 Free Software Foundation, Inc.
   4    Contributed by Jiri Smid, SuSE Labs.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "inferior.h"
  23 #include "regcache.h"
  24 #include "elf/common.h"
  25 #include <sys/uio.h>
  26 #include "nat/gdb_ptrace.h"
  27 #include <asm/prctl.h>
  28 #include <sys/reg.h>
  29 #include "gregset.h"
  30 #include "gdb_proc_service.h"
  31
  32 #include "amd64-nat.h"
  33 #include "linux-nat.h"
  34 #include "amd64-tdep.h"
  35 #include "amd64-linux-tdep.h"
  36 #include "i386-linux-tdep.h"
  37 #include "x86-xstate.h"
  38
  39 #include "x86-linux-nat.h"
  40 #include "nat/linux-ptrace.h"
  41 #include "nat/amd64-linux-siginfo.h"
  42
  43 /* This definition comes from prctl.h.  Kernels older than 2.5.64
  44    do not have it.  */
  45 #ifndef PTRACE_ARCH_PRCTL
  46 #define PTRACE_ARCH_PRCTL      30
  47 #endif
  48
  49 /* Mapping between the general-purpose registers in GNU/Linux x86-64
  50    `struct user' format and GDB's register cache layout for GNU/Linux
  51    i386.
  52
  53    Note that most GNU/Linux x86-64 registers are 64-bit, while the
  54    GNU/Linux i386 registers are all 32-bit, but since we're
  55    little-endian we get away with that.  */
  56
  57 /* From <sys/reg.h> on GNU/Linux i386.  */
  58 static int amd64_linux_gregset32_reg_offset[] =
  59 {
  60   RAX * 8, RCX * 8,             /* %eax, %ecx */
  61   RDX * 8, RBX * 8,             /* %edx, %ebx */
  62   RSP * 8, RBP * 8,             /* %esp, %ebp */
  63   RSI * 8, RDI * 8,             /* %esi, %edi */
  64   RIP * 8, EFLAGS * 8,          /* %eip, %eflags */
  65   CS * 8, SS * 8,               /* %cs, %ss */
  66   DS * 8, ES * 8,               /* %ds, %es */
  67   FS * 8, GS * 8,               /* %fs, %gs */
  68   -1, -1, -1, -1, -1, -1, -1, -1,
  69   -1, -1, -1, -1, -1, -1, -1, -1,
  70   -1, -1, -1, -1, -1, -1, -1, -1, -1,
  71   -1, -1, -1, -1, -1, -1, -1, -1,
  72   -1, -1, -1, -1,                 /* MPX registers BND0 ... BND3.  */
  73   -1, -1,                         /* MPX registers BNDCFGU, BNDSTATUS.  */
  74   -1, -1, -1, -1, -1, -1, -1, -1, /* k0 ... k7 (AVX512)  */
  75   -1, -1, -1, -1, -1, -1, -1, -1, /* zmm0 ... zmm7 (AVX512)  */
  76   -1,                             /* PKEYS register PKRU  */
  77   ORIG_RAX * 8                    /* "orig_eax"  */
  78 };
  79 \f
  80
  81 /* Transfering the general-purpose registers between GDB, inferiors
  82    and core files.  */
  83
  84 /* Fill GDB's register cache with the general-purpose register values
  85    in *GREGSETP.  */
  86
  87 void
  88 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
  89 {
  90   amd64_supply_native_gregset (regcache, gregsetp, -1);
  91 }
  92
  93 /* Fill register REGNUM (if it is a general-purpose register) in
  94    *GREGSETP with the value in GDB's register cache.  If REGNUM is -1,
  95    do this for all registers.  */
  96
  97 void
  98 fill_gregset (const struct regcache *regcache,
  99               elf_gregset_t *gregsetp, int regnum)
 100 {
 101   amd64_collect_native_gregset (regcache, gregsetp, regnum);
 102 }
 103
 104 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 105
 106 /* Fill GDB's register cache with the floating-point and SSE register
 107    values in *FPREGSETP.  */
 108
 109 void
 110 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 111 {
 112   amd64_supply_fxsave (regcache, -1, fpregsetp);
 113 }
 114
 115 /* Fill register REGNUM (if it is a floating-point or SSE register) in
 116    *FPREGSETP with the value in GDB's register cache.  If REGNUM is
 117    -1, do this for all registers.  */
 118
 119 void
 120 fill_fpregset (const struct regcache *regcache,
 121                elf_fpregset_t *fpregsetp, int regnum)
 122 {
 123   amd64_collect_fxsave (regcache, regnum, fpregsetp);
 124 }
 125 \f
 126
 127 /* Transferring arbitrary registers between GDB and inferior.  */
 128
 129 /* Fetch register REGNUM from the child process.  If REGNUM is -1, do
 130    this for all registers (including the floating point and SSE
 131    registers).  */
 132
 133 static void
 134 amd64_linux_fetch_inferior_registers (struct target_ops *ops,
 135                                       struct regcache *regcache, int regnum)
 136 {
 137   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 138   int tid;
 139
 140   /* GNU/Linux LWP ID's are process ID's.  */
 141   tid = ptid_get_lwp (inferior_ptid);
 142   if (tid == 0)
 143     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 144
 145   if (regnum == -1 || amd64_native_gregset_supplies_p (gdbarch, regnum))
 146     {
 147       elf_gregset_t regs;
 148
 149       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 150         perror_with_name (_("Couldn't get registers"));
 151
 152       amd64_supply_native_gregset (regcache, &regs, -1);
 153       if (regnum != -1)
 154         return;
 155     }
 156
 157   if (regnum == -1 || !amd64_native_gregset_supplies_p (gdbarch, regnum))
 158     {
 159       elf_fpregset_t fpregs;
 160
 161       if (have_ptrace_getregset == TRIBOOL_TRUE)
 162         {
 163           char xstateregs[X86_XSTATE_MAX_SIZE];
 164           struct iovec iov;
 165
 166           iov.iov_base = xstateregs;
 167           iov.iov_len = sizeof (xstateregs);
 168           if (ptrace (PTRACE_GETREGSET, tid,
 169                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 170             perror_with_name (_("Couldn't get extended state status"));
 171
 172           amd64_supply_xsave (regcache, -1, xstateregs);
 173         }
 174       else
 175         {
 176           if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 177             perror_with_name (_("Couldn't get floating point status"));
 178
 179           amd64_supply_fxsave (regcache, -1, &fpregs);
 180         }
 181 #ifndef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
 182       {
 183         /* PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the
 184            fs_base and gs_base fields of user_regs_struct can be
 185            used directly.  */
 186         unsigned long base;
 187
 188         if (regnum == -1 || regnum == AMD64_FSBASE_REGNUM)
 189           {
 190             if (ptrace (PTRACE_ARCH_PRCTL, tid, &base, ARCH_GET_FS) < 0)
 191               perror_with_name (_("Couldn't get segment register fs_base"));
 192
 193             regcache_raw_supply (regcache, AMD64_FSBASE_REGNUM, &base);
 194           }
 195
 196         if (regnum == -1 || regnum == AMD64_GSBASE_REGNUM)
 197           {
 198             if (ptrace (PTRACE_ARCH_PRCTL, tid, &base, ARCH_GET_GS) < 0)
 199               perror_with_name (_("Couldn't get segment register gs_base"));
 200
 201             regcache_raw_supply (regcache, AMD64_GSBASE_REGNUM, &base);
 202           }
 203       }
 204 #endif
 205     }
 206 }
 207
 208 /* Store register REGNUM back into the child process.  If REGNUM is
 209    -1, do this for all registers (including the floating-point and SSE
 210    registers).  */
 211
 212 static void
 213 amd64_linux_store_inferior_registers (struct target_ops *ops,
 214                                       struct regcache *regcache, int regnum)
 215 {
 216   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 217   int tid;
 218
 219   /* GNU/Linux LWP ID's are process ID's.  */
 220   tid = ptid_get_lwp (inferior_ptid);
 221   if (tid == 0)
 222     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 223
 224   if (regnum == -1 || amd64_native_gregset_supplies_p (gdbarch, regnum))
 225     {
 226       elf_gregset_t regs;
 227
 228       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 229         perror_with_name (_("Couldn't get registers"));
 230
 231       amd64_collect_native_gregset (regcache, &regs, regnum);
 232
 233       if (ptrace (PTRACE_SETREGS, tid, 0, (long) &regs) < 0)
 234         perror_with_name (_("Couldn't write registers"));
 235
 236       if (regnum != -1)
 237         return;
 238     }
 239
 240   if (regnum == -1 || !amd64_native_gregset_supplies_p (gdbarch, regnum))
 241     {
 242       elf_fpregset_t fpregs;
 243
 244       if (have_ptrace_getregset == TRIBOOL_TRUE)
 245         {
 246           char xstateregs[X86_XSTATE_MAX_SIZE];
 247           struct iovec iov;
 248
 249           iov.iov_base = xstateregs;
 250           iov.iov_len = sizeof (xstateregs);
 251           if (ptrace (PTRACE_GETREGSET, tid,
 252                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 253             perror_with_name (_("Couldn't get extended state status"));
 254
 255           amd64_collect_xsave (regcache, regnum, xstateregs, 0);
 256
 257           if (ptrace (PTRACE_SETREGSET, tid,
 258                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 259             perror_with_name (_("Couldn't write extended state status"));
 260         }
 261       else
 262         {
 263           if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 264             perror_with_name (_("Couldn't get floating point status"));
 265
 266           amd64_collect_fxsave (regcache, regnum, &fpregs);
 267
 268           if (ptrace (PTRACE_SETFPREGS, tid, 0, (long) &fpregs) < 0)
 269             perror_with_name (_("Couldn't write floating point status"));
 270         }
 271
 272 #ifndef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
 273       {
 274         /* PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the
 275            fs_base and gs_base fields of user_regs_struct can be
 276            used directly.  */
 277         void *base;
 278
 279         if (regnum == -1 || regnum == AMD64_FSBASE_REGNUM)
 280           {
 281             regcache_raw_collect (regcache, AMD64_FSBASE_REGNUM, &base);
 282
 283             if (ptrace (PTRACE_ARCH_PRCTL, tid, base, ARCH_SET_FS) < 0)
 284               perror_with_name (_("Couldn't write segment register fs_base"));
 285           }
 286         if (regnum == -1 || regnum == AMD64_GSBASE_REGNUM)
 287           {
 288
 289             regcache_raw_collect (regcache, AMD64_GSBASE_REGNUM, &base);
 290             if (ptrace (PTRACE_ARCH_PRCTL, tid, base, ARCH_SET_GS) < 0)
 291               perror_with_name (_("Couldn't write segment register gs_base"));
 292           }
 293       }
 294 #endif
 295     }
 296 }
 297 \f
 298
 299 /* This function is called by libthread_db as part of its handling of
 300    a request for a thread's local storage address.  */
 301
 302 ps_err_e
 303 ps_get_thread_area (struct ps_prochandle *ph,
 304                     lwpid_t lwpid, int idx, void **base)
 305 {
 306   if (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 32)
 307     {
 308       unsigned int base_addr;
 309       ps_err_e result;
 310
 311       result = x86_linux_get_thread_area (lwpid, (void *) (long) idx,
 312                                           &base_addr);
 313       if (result == PS_OK)
 314         {
 315           /* Extend the value to 64 bits.  Here it's assumed that
 316              a "long" and a "void *" are the same.  */
 317           (*base) = (void *) (long) base_addr;
 318         }
 319       return result;
 320     }
 321   else
 322     {
 323
 324       /* FIXME: ezannoni-2003-07-09 see comment above about include
 325          file order.  We could be getting bogus values for these two.  */
 326       gdb_assert (FS < ELF_NGREG);
 327       gdb_assert (GS < ELF_NGREG);
 328       switch (idx)
 329         {
 330         case FS:
 331 #ifdef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
 332             {
 333               /* PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the
 334                  fs_base and gs_base fields of user_regs_struct can be
 335                  used directly.  */
 336               unsigned long fs;
 337               errno = 0;
 338               fs = ptrace (PTRACE_PEEKUSER, lwpid,
 339                            offsetof (struct user_regs_struct, fs_base), 0);
 340               if (errno == 0)
 341                 {
 342                   *base = (void *) fs;
 343                   return PS_OK;
 344                 }
 345             }
 346 #endif
 347           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
 348             return PS_OK;
 349           break;
 350         case GS:
 351 #ifdef HAVE_STRUCT_USER_REGS_STRUCT_GS_BASE
 352             {
 353               unsigned long gs;
 354               errno = 0;
 355               gs = ptrace (PTRACE_PEEKUSER, lwpid,
 356                            offsetof (struct user_regs_struct, gs_base), 0);
 357               if (errno == 0)
 358                 {
 359                   *base = (void *) gs;
 360                   return PS_OK;
 361                 }
 362             }
 363 #endif
 364           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
 365             return PS_OK;
 366           break;
 367         default:                   /* Should not happen.  */
 368           return PS_BADADDR;
 369         }
 370     }
 371   return PS_ERR;               /* ptrace failed.  */
 372 }
 373 \f
 374
 375 /* Convert a ptrace/host siginfo object, into/from the siginfo in the
 376    layout of the inferiors' architecture.  Returns true if any
 377    conversion was done; false otherwise.  If DIRECTION is 1, then copy
 378    from INF to PTRACE.  If DIRECTION is 0, copy from PTRACE to
 379    INF.  */
 380
 381 static int
 382 amd64_linux_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
 383 {
 384   struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
 385
 386   /* Is the inferior 32-bit?  If so, then do fixup the siginfo
 387      object.  */
 388   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 389       return amd64_linux_siginfo_fixup_common (ptrace, inf, direction,
 390                                                FIXUP_32);
 391   /* No fixup for native x32 GDB.  */
 392   else if (gdbarch_addr_bit (gdbarch) == 32 && sizeof (void *) == 8)
 393       return amd64_linux_siginfo_fixup_common (ptrace, inf, direction,
 394                                                FIXUP_X32);
 395   else
 396     return 0;
 397 }
 398
 399 /* Provide a prototype to silence -Wmissing-prototypes.  */
 400 void _initialize_amd64_linux_nat (void);
 401
 402 void
 403 _initialize_amd64_linux_nat (void)
 404 {
 405   struct target_ops *t;
 406
 407   amd64_native_gregset32_reg_offset = amd64_linux_gregset32_reg_offset;
 408   amd64_native_gregset32_num_regs = I386_LINUX_NUM_REGS;
 409   amd64_native_gregset64_reg_offset = amd64_linux_gregset_reg_offset;
 410   amd64_native_gregset64_num_regs = AMD64_LINUX_NUM_REGS;
 411
 412   gdb_assert (ARRAY_SIZE (amd64_linux_gregset32_reg_offset)
 413               == amd64_native_gregset32_num_regs);
 414
 415   /* Create a generic x86 GNU/Linux target.  */
 416   t = x86_linux_create_target ();
 417
 418   /* Add our register access methods.  */
 419   t->to_fetch_registers = amd64_linux_fetch_inferior_registers;
 420   t->to_store_registers = amd64_linux_store_inferior_registers;
 421
 422   /* Add the target.  */
 423   x86_linux_add_target (t);
 424
 425   /* Add our siginfo layout converter.  */
 426   linux_nat_set_siginfo_fixup (t, amd64_linux_siginfo_fixup);
 427 }