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   ORIG_RAX * 8                    /* "orig_eax"  */
  77 };
  78 \f
  79
  80 /* Transfering the general-purpose registers between GDB, inferiors
  81    and core files.  */
  82
  83 /* Fill GDB's register cache with the general-purpose register values
  84    in *GREGSETP.  */
  85
  86 void
  87 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
  88 {
  89   amd64_supply_native_gregset (regcache, gregsetp, -1);
  90 }
  91
  92 /* Fill register REGNUM (if it is a general-purpose register) in
  93    *GREGSETP with the value in GDB's register cache.  If REGNUM is -1,
  94    do this for all registers.  */
  95
  96 void
  97 fill_gregset (const struct regcache *regcache,
  98               elf_gregset_t *gregsetp, int regnum)
  99 {
 100   amd64_collect_native_gregset (regcache, gregsetp, regnum);
 101 }
 102
 103 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 104
 105 /* Fill GDB's register cache with the floating-point and SSE register
 106    values in *FPREGSETP.  */
 107
 108 void
 109 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 110 {
 111   amd64_supply_fxsave (regcache, -1, fpregsetp);
 112 }
 113
 114 /* Fill register REGNUM (if it is a floating-point or SSE register) in
 115    *FPREGSETP with the value in GDB's register cache.  If REGNUM is
 116    -1, do this for all registers.  */
 117
 118 void
 119 fill_fpregset (const struct regcache *regcache,
 120                elf_fpregset_t *fpregsetp, int regnum)
 121 {
 122   amd64_collect_fxsave (regcache, regnum, fpregsetp);
 123 }
 124 \f
 125
 126 /* Transferring arbitrary registers between GDB and inferior.  */
 127
 128 /* Fetch register REGNUM from the child process.  If REGNUM is -1, do
 129    this for all registers (including the floating point and SSE
 130    registers).  */
 131
 132 static void
 133 amd64_linux_fetch_inferior_registers (struct target_ops *ops,
 134                                       struct regcache *regcache, int regnum)
 135 {
 136   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 137   int tid;
 138
 139   /* GNU/Linux LWP ID's are process ID's.  */
 140   tid = ptid_get_lwp (inferior_ptid);
 141   if (tid == 0)
 142     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 143
 144   if (regnum == -1 || amd64_native_gregset_supplies_p (gdbarch, regnum))
 145     {
 146       elf_gregset_t regs;
 147
 148       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 149         perror_with_name (_("Couldn't get registers"));
 150
 151       amd64_supply_native_gregset (regcache, &regs, -1);
 152       if (regnum != -1)
 153         return;
 154     }
 155
 156   if (regnum == -1 || !amd64_native_gregset_supplies_p (gdbarch, regnum))
 157     {
 158       elf_fpregset_t fpregs;
 159
 160       if (have_ptrace_getregset == TRIBOOL_TRUE)
 161         {
 162           char xstateregs[X86_XSTATE_MAX_SIZE];
 163           struct iovec iov;
 164
 165           iov.iov_base = xstateregs;
 166           iov.iov_len = sizeof (xstateregs);
 167           if (ptrace (PTRACE_GETREGSET, tid,
 168                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 169             perror_with_name (_("Couldn't get extended state status"));
 170
 171           amd64_supply_xsave (regcache, -1, xstateregs);
 172         }
 173       else
 174         {
 175           if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 176             perror_with_name (_("Couldn't get floating point status"));
 177
 178           amd64_supply_fxsave (regcache, -1, &fpregs);
 179         }
 180 #ifndef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
 181       {
 182         /* PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the
 183            fs_base and gs_base fields of user_regs_struct can be
 184            used directly.  */
 185         unsigned long base;
 186
 187         if (regnum == -1 || regnum == AMD64_FSBASE_REGNUM)
 188           {
 189             if (ptrace (PTRACE_ARCH_PRCTL, tid, &base, ARCH_GET_FS) < 0)
 190               perror_with_name (_("Couldn't get segment register fs_base"));
 191
 192             regcache_raw_supply (regcache, AMD64_FSBASE_REGNUM, &base);
 193           }
 194
 195         if (regnum == -1 || regnum == AMD64_GSBASE_REGNUM)
 196           {
 197             if (ptrace (PTRACE_ARCH_PRCTL, tid, &base, ARCH_GET_GS) < 0)
 198               perror_with_name (_("Couldn't get segment register gs_base"));
 199
 200             regcache_raw_supply (regcache, AMD64_GSBASE_REGNUM, &base);
 201           }
 202       }
 203 #endif
 204     }
 205 }
 206
 207 /* Store register REGNUM back into the child process.  If REGNUM is
 208    -1, do this for all registers (including the floating-point and SSE
 209    registers).  */
 210
 211 static void
 212 amd64_linux_store_inferior_registers (struct target_ops *ops,
 213                                       struct regcache *regcache, int regnum)
 214 {
 215   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 216   int tid;
 217
 218   /* GNU/Linux LWP ID's are process ID's.  */
 219   tid = ptid_get_lwp (inferior_ptid);
 220   if (tid == 0)
 221     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 222
 223   if (regnum == -1 || amd64_native_gregset_supplies_p (gdbarch, regnum))
 224     {
 225       elf_gregset_t regs;
 226
 227       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 228         perror_with_name (_("Couldn't get registers"));
 229
 230       amd64_collect_native_gregset (regcache, &regs, regnum);
 231
 232       if (ptrace (PTRACE_SETREGS, tid, 0, (long) &regs) < 0)
 233         perror_with_name (_("Couldn't write registers"));
 234
 235       if (regnum != -1)
 236         return;
 237     }
 238
 239   if (regnum == -1 || !amd64_native_gregset_supplies_p (gdbarch, regnum))
 240     {
 241       elf_fpregset_t fpregs;
 242
 243       if (have_ptrace_getregset == TRIBOOL_TRUE)
 244         {
 245           char xstateregs[X86_XSTATE_MAX_SIZE];
 246           struct iovec iov;
 247
 248           iov.iov_base = xstateregs;
 249           iov.iov_len = sizeof (xstateregs);
 250           if (ptrace (PTRACE_GETREGSET, tid,
 251                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 252             perror_with_name (_("Couldn't get extended state status"));
 253
 254           amd64_collect_xsave (regcache, regnum, xstateregs, 0);
 255
 256           if (ptrace (PTRACE_SETREGSET, tid,
 257                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 258             perror_with_name (_("Couldn't write extended state status"));
 259         }
 260       else
 261         {
 262           if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 263             perror_with_name (_("Couldn't get floating point status"));
 264
 265           amd64_collect_fxsave (regcache, regnum, &fpregs);
 266
 267           if (ptrace (PTRACE_SETFPREGS, tid, 0, (long) &fpregs) < 0)
 268             perror_with_name (_("Couldn't write floating point status"));
 269         }
 270
 271 #ifndef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
 272       {
 273         /* PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the
 274            fs_base and gs_base fields of user_regs_struct can be
 275            used directly.  */
 276         void *base;
 277
 278         if (regnum == -1 || regnum == AMD64_FSBASE_REGNUM)
 279           {
 280             regcache_raw_collect (regcache, AMD64_FSBASE_REGNUM, &base);
 281
 282             if (ptrace (PTRACE_ARCH_PRCTL, tid, base, ARCH_SET_FS) < 0)
 283               perror_with_name (_("Couldn't write segment register fs_base"));
 284           }
 285         if (regnum == -1 || regnum == AMD64_GSBASE_REGNUM)
 286           {
 287
 288             regcache_raw_collect (regcache, AMD64_GSBASE_REGNUM, &base);
 289             if (ptrace (PTRACE_ARCH_PRCTL, tid, base, ARCH_SET_GS) < 0)
 290               perror_with_name (_("Couldn't write segment register gs_base"));
 291           }
 292       }
 293 #endif
 294     }
 295 }
 296 \f
 297
 298 /* This function is called by libthread_db as part of its handling of
 299    a request for a thread's local storage address.  */
 300
 301 ps_err_e
 302 ps_get_thread_area (struct ps_prochandle *ph,
 303                     lwpid_t lwpid, int idx, void **base)
 304 {
 305   if (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 32)
 306     {
 307       unsigned int base_addr;
 308       ps_err_e result;
 309
 310       result = x86_linux_get_thread_area (lwpid, (void *) (long) idx,
 311                                           &base_addr);
 312       if (result == PS_OK)
 313         {
 314           /* Extend the value to 64 bits.  Here it's assumed that
 315              a "long" and a "void *" are the same.  */
 316           (*base) = (void *) (long) base_addr;
 317         }
 318       return result;
 319     }
 320   else
 321     {
 322
 323       /* FIXME: ezannoni-2003-07-09 see comment above about include
 324          file order.  We could be getting bogus values for these two.  */
 325       gdb_assert (FS < ELF_NGREG);
 326       gdb_assert (GS < ELF_NGREG);
 327       switch (idx)
 328         {
 329         case FS:
 330 #ifdef HAVE_STRUCT_USER_REGS_STRUCT_FS_BASE
 331             {
 332               /* PTRACE_ARCH_PRCTL is obsolete since 2.6.25, where the
 333                  fs_base and gs_base fields of user_regs_struct can be
 334                  used directly.  */
 335               unsigned long fs;
 336               errno = 0;
 337               fs = ptrace (PTRACE_PEEKUSER, lwpid,
 338                            offsetof (struct user_regs_struct, fs_base), 0);
 339               if (errno == 0)
 340                 {
 341                   *base = (void *) fs;
 342                   return PS_OK;
 343                 }
 344             }
 345 #endif
 346           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
 347             return PS_OK;
 348           break;
 349         case GS:
 350 #ifdef HAVE_STRUCT_USER_REGS_STRUCT_GS_BASE
 351             {
 352               unsigned long gs;
 353               errno = 0;
 354               gs = ptrace (PTRACE_PEEKUSER, lwpid,
 355                            offsetof (struct user_regs_struct, gs_base), 0);
 356               if (errno == 0)
 357                 {
 358                   *base = (void *) gs;
 359                   return PS_OK;
 360                 }
 361             }
 362 #endif
 363           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
 364             return PS_OK;
 365           break;
 366         default:                   /* Should not happen.  */
 367           return PS_BADADDR;
 368         }
 369     }
 370   return PS_ERR;               /* ptrace failed.  */
 371 }
 372 \f
 373
 374 /* Convert a ptrace/host siginfo object, into/from the siginfo in the
 375    layout of the inferiors' architecture.  Returns true if any
 376    conversion was done; false otherwise.  If DIRECTION is 1, then copy
 377    from INF to PTRACE.  If DIRECTION is 0, copy from PTRACE to
 378    INF.  */
 379
 380 static int
 381 amd64_linux_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
 382 {
 383   struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
 384
 385   /* Is the inferior 32-bit?  If so, then do fixup the siginfo
 386      object.  */
 387   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 388       return amd64_linux_siginfo_fixup_common (ptrace, inf, direction,
 389                                                FIXUP_32);
 390   /* No fixup for native x32 GDB.  */
 391   else if (gdbarch_addr_bit (gdbarch) == 32 && sizeof (void *) == 8)
 392       return amd64_linux_siginfo_fixup_common (ptrace, inf, direction,
 393                                                FIXUP_X32);
 394   else
 395     return 0;
 396 }
 397
 398 /* Provide a prototype to silence -Wmissing-prototypes.  */
 399 void _initialize_amd64_linux_nat (void);
 400
 401 void
 402 _initialize_amd64_linux_nat (void)
 403 {
 404   struct target_ops *t;
 405
 406   amd64_native_gregset32_reg_offset = amd64_linux_gregset32_reg_offset;
 407   amd64_native_gregset32_num_regs = I386_LINUX_NUM_REGS;
 408   amd64_native_gregset64_reg_offset = amd64_linux_gregset_reg_offset;
 409   amd64_native_gregset64_num_regs = AMD64_LINUX_NUM_REGS;
 410
 411   gdb_assert (ARRAY_SIZE (amd64_linux_gregset32_reg_offset)
 412               == amd64_native_gregset32_num_regs);
 413
 414   /* Create a generic x86 GNU/Linux target.  */
 415   t = x86_linux_create_target ();
 416
 417   /* Add our register access methods.  */
 418   t->to_fetch_registers = amd64_linux_fetch_inferior_registers;
 419   t->to_store_registers = amd64_linux_store_inferior_registers;
 420
 421   /* Add the target.  */
 422   x86_linux_add_target (t);
 423
 424   /* Add our siginfo layout converter.  */
 425   linux_nat_set_siginfo_fixup (t, amd64_linux_siginfo_fixup);
 426 }