gdb/amd64-linux-nat.c

   1 /* Native-dependent code for GNU/Linux x86-64.
   2
   3    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
   4    Free Software Foundation, Inc.
   5    Contributed by Jiri Smid, SuSE Labs.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26 #include "linux-nat.h"
  27 #include "amd64-linux-tdep.h"
  28
  29 #include "gdb_assert.h"
  30 #include "gdb_string.h"
  31 #include <sys/ptrace.h>
  32 #include <sys/debugreg.h>
  33 #include <sys/syscall.h>
  34 #include <sys/procfs.h>
  35 #include <asm/prctl.h>
  36 /* FIXME ezannoni-2003-07-09: we need <sys/reg.h> to be included after
  37    <asm/ptrace.h> because the latter redefines FS and GS for no apparent
  38    reason, and those definitions don't match the ones that libpthread_db
  39    uses, which come from <sys/reg.h>.  */
  40 /* ezannoni-2003-07-09: I think this is fixed. The extraneous defs have
  41    been removed from ptrace.h in the kernel.  However, better safe than
  42    sorry.  */
  43 #include <asm/ptrace.h>
  44 #include <sys/reg.h>
  45 #include "gdb_proc_service.h"
  46
  47 /* Prototypes for supply_gregset etc.  */
  48 #include "gregset.h"
  49
  50 #include "amd64-tdep.h"
  51 #include "i386-linux-tdep.h"
  52 #include "amd64-nat.h"
  53
  54 /* Mapping between the general-purpose registers in GNU/Linux x86-64
  55    `struct user' format and GDB's register cache layout.  */
  56
  57 static int amd64_linux_gregset64_reg_offset[] =
  58 {
  59   RAX * 8, RBX * 8,             /* %rax, %rbx */
  60   RCX * 8, RDX * 8,             /* %rcx, %rdx */
  61   RSI * 8, RDI * 8,             /* %rsi, %rdi */
  62   RBP * 8, RSP * 8,             /* %rbp, %rsp */
  63   R8 * 8, R9 * 8,               /* %r8 ... */
  64   R10 * 8, R11 * 8,
  65   R12 * 8, R13 * 8,
  66   R14 * 8, R15 * 8,             /* ... %r15 */
  67   RIP * 8, EFLAGS * 8,          /* %rip, %eflags */
  68   CS * 8, SS * 8,               /* %cs, %ss */
  69   DS * 8, ES * 8,               /* %ds, %es */
  70   FS * 8, GS * 8,               /* %fs, %gs */
  71   -1, -1, -1, -1, -1, -1, -1, -1,
  72   -1, -1, -1, -1, -1, -1, -1, -1,
  73   -1, -1, -1, -1, -1, -1, -1, -1,
  74   -1, -1, -1, -1, -1, -1, -1, -1, -1,
  75   ORIG_RAX * 8
  76 };
  77 \f
  78
  79 /* Mapping between the general-purpose registers in GNU/Linux x86-64
  80    `struct user' format and GDB's register cache layout for GNU/Linux
  81    i386.
  82
  83    Note that most GNU/Linux x86-64 registers are 64-bit, while the
  84    GNU/Linux i386 registers are all 32-bit, but since we're
  85    little-endian we get away with that.  */
  86
  87 /* From <sys/reg.h> on GNU/Linux i386.  */
  88 static int amd64_linux_gregset32_reg_offset[] =
  89 {
  90   RAX * 8, RCX * 8,             /* %eax, %ecx */
  91   RDX * 8, RBX * 8,             /* %edx, %ebx */
  92   RSP * 8, RBP * 8,             /* %esp, %ebp */
  93   RSI * 8, RDI * 8,             /* %esi, %edi */
  94   RIP * 8, EFLAGS * 8,          /* %eip, %eflags */
  95   CS * 8, SS * 8,               /* %cs, %ss */
  96   DS * 8, ES * 8,               /* %ds, %es */
  97   FS * 8, GS * 8,               /* %fs, %gs */
  98   -1, -1, -1, -1, -1, -1, -1, -1,
  99   -1, -1, -1, -1, -1, -1, -1, -1,
 100   -1, -1, -1, -1, -1, -1, -1, -1, -1,
 101   ORIG_RAX * 8                  /* "orig_eax" */
 102 };
 103 \f
 104
 105 /* Transfering the general-purpose registers between GDB, inferiors
 106    and core files.  */
 107
 108 /* Fill GDB's register cache with the general-purpose register values
 109    in *GREGSETP.  */
 110
 111 void
 112 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 113 {
 114   amd64_supply_native_gregset (regcache, gregsetp, -1);
 115 }
 116
 117 /* Fill register REGNUM (if it is a general-purpose register) in
 118    *GREGSETP with the value in GDB's register cache.  If REGNUM is -1,
 119    do this for all registers.  */
 120
 121 void
 122 fill_gregset (const struct regcache *regcache,
 123               elf_gregset_t *gregsetp, int regnum)
 124 {
 125   amd64_collect_native_gregset (regcache, gregsetp, regnum);
 126 }
 127
 128 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 129
 130 /* Fill GDB's register cache with the floating-point and SSE register
 131    values in *FPREGSETP.  */
 132
 133 void
 134 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 135 {
 136   amd64_supply_fxsave (regcache, -1, fpregsetp);
 137 }
 138
 139 /* Fill register REGNUM (if it is a floating-point or SSE register) in
 140    *FPREGSETP with the value in GDB's register cache.  If REGNUM is
 141    -1, do this for all registers.  */
 142
 143 void
 144 fill_fpregset (const struct regcache *regcache,
 145                elf_fpregset_t *fpregsetp, int regnum)
 146 {
 147   amd64_collect_fxsave (regcache, regnum, fpregsetp);
 148 }
 149 \f
 150
 151 /* Transferring arbitrary registers between GDB and inferior.  */
 152
 153 /* Fetch register REGNUM from the child process.  If REGNUM is -1, do
 154    this for all registers (including the floating point and SSE
 155    registers).  */
 156
 157 static void
 158 amd64_linux_fetch_inferior_registers (struct regcache *regcache, int regnum)
 159 {
 160   int tid;
 161
 162   /* GNU/Linux LWP ID's are process ID's.  */
 163   tid = TIDGET (inferior_ptid);
 164   if (tid == 0)
 165     tid = PIDGET (inferior_ptid); /* Not a threaded program.  */
 166
 167   if (regnum == -1 || amd64_native_gregset_supplies_p (regnum))
 168     {
 169       elf_gregset_t regs;
 170
 171       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 172         perror_with_name (_("Couldn't get registers"));
 173
 174       amd64_supply_native_gregset (regcache, &regs, -1);
 175       if (regnum != -1)
 176         return;
 177     }
 178
 179   if (regnum == -1 || !amd64_native_gregset_supplies_p (regnum))
 180     {
 181       elf_fpregset_t fpregs;
 182
 183       if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 184         perror_with_name (_("Couldn't get floating point status"));
 185
 186       amd64_supply_fxsave (regcache, -1, &fpregs);
 187     }
 188 }
 189
 190 /* Store register REGNUM back into the child process.  If REGNUM is
 191    -1, do this for all registers (including the floating-point and SSE
 192    registers).  */
 193
 194 static void
 195 amd64_linux_store_inferior_registers (struct regcache *regcache, int regnum)
 196 {
 197   int tid;
 198
 199   /* GNU/Linux LWP ID's are process ID's.  */
 200   tid = TIDGET (inferior_ptid);
 201   if (tid == 0)
 202     tid = PIDGET (inferior_ptid); /* Not a threaded program.  */
 203
 204   if (regnum == -1 || amd64_native_gregset_supplies_p (regnum))
 205     {
 206       elf_gregset_t regs;
 207
 208       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 209         perror_with_name (_("Couldn't get registers"));
 210
 211       amd64_collect_native_gregset (regcache, &regs, regnum);
 212
 213       if (ptrace (PTRACE_SETREGS, tid, 0, (long) &regs) < 0)
 214         perror_with_name (_("Couldn't write registers"));
 215
 216       if (regnum != -1)
 217         return;
 218     }
 219
 220   if (regnum == -1 || !amd64_native_gregset_supplies_p (regnum))
 221     {
 222       elf_fpregset_t fpregs;
 223
 224       if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 225         perror_with_name (_("Couldn't get floating point status"));
 226
 227       amd64_collect_fxsave (regcache, regnum, &fpregs);
 228
 229       if (ptrace (PTRACE_SETFPREGS, tid, 0, (long) &fpregs) < 0)
 230         perror_with_name (_("Couldn't write floating point status"));
 231
 232       return;
 233     }
 234 }
 235 \f
 236
 237 static unsigned long
 238 amd64_linux_dr_get (int regnum)
 239 {
 240   int tid;
 241   unsigned long value;
 242
 243   /* FIXME: kettenis/2001-01-29: It's not clear what we should do with
 244      multi-threaded processes here.  For now, pretend there is just
 245      one thread.  */
 246   tid = PIDGET (inferior_ptid);
 247
 248   /* FIXME: kettenis/2001-03-27: Calling perror_with_name if the
 249      ptrace call fails breaks debugging remote targets.  The correct
 250      way to fix this is to add the hardware breakpoint and watchpoint
 251      stuff to the target vectore.  For now, just return zero if the
 252      ptrace call fails.  */
 253   errno = 0;
 254   value = ptrace (PT_READ_U, tid,
 255                   offsetof (struct user, u_debugreg[regnum]), 0);
 256   if (errno != 0)
 257 #if 0
 258     perror_with_name (_("Couldn't read debug register"));
 259 #else
 260     return 0;
 261 #endif
 262
 263   return value;
 264 }
 265
 266 static void
 267 amd64_linux_dr_set (int regnum, unsigned long value)
 268 {
 269   int tid;
 270
 271   /* FIXME: kettenis/2001-01-29: It's not clear what we should do with
 272      multi-threaded processes here.  For now, pretend there is just
 273      one thread.  */
 274   tid = PIDGET (inferior_ptid);
 275
 276   errno = 0;
 277   ptrace (PT_WRITE_U, tid, offsetof (struct user, u_debugreg[regnum]), value);
 278   if (errno != 0)
 279     perror_with_name (_("Couldn't write debug register"));
 280 }
 281
 282 void
 283 amd64_linux_dr_set_control (unsigned long control)
 284 {
 285   amd64_linux_dr_set (DR_CONTROL, control);
 286 }
 287
 288 void
 289 amd64_linux_dr_set_addr (int regnum, CORE_ADDR addr)
 290 {
 291   gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
 292
 293   amd64_linux_dr_set (DR_FIRSTADDR + regnum, addr);
 294 }
 295
 296 void
 297 amd64_linux_dr_reset_addr (int regnum)
 298 {
 299   gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
 300
 301   amd64_linux_dr_set (DR_FIRSTADDR + regnum, 0L);
 302 }
 303
 304 unsigned long
 305 amd64_linux_dr_get_status (void)
 306 {
 307   return amd64_linux_dr_get (DR_STATUS);
 308 }
 309 \f
 310
 311 /* This function is called by libthread_db as part of its handling of
 312    a request for a thread's local storage address.  */
 313
 314 ps_err_e
 315 ps_get_thread_area (const struct ps_prochandle *ph,
 316                     lwpid_t lwpid, int idx, void **base)
 317 {
 318   if (gdbarch_ptr_bit (current_gdbarch) == 32)
 319     {
 320       /* The full structure is found in <asm-i386/ldt.h>.  The second
 321          integer is the LDT's base_address and that is used to locate
 322          the thread's local storage.  See i386-linux-nat.c more
 323          info.  */
 324       unsigned int desc[4];
 325
 326       /* This code assumes that "int" is 32 bits and that
 327          GET_THREAD_AREA returns no more than 4 int values.  */
 328       gdb_assert (sizeof (int) == 4);
 329 #ifndef PTRACE_GET_THREAD_AREA
 330 #define PTRACE_GET_THREAD_AREA 25
 331 #endif
 332       if  (ptrace (PTRACE_GET_THREAD_AREA,
 333                    lwpid, (void *) (long) idx, (unsigned long) &desc) < 0)
 334         return PS_ERR;
 335
 336       /* Extend the value to 64 bits.  Here it's assumed that a "long"
 337          and a "void *" are the same.  */
 338       (*base) = (void *) (long) desc[1];
 339       return PS_OK;
 340     }
 341   else
 342     {
 343       /* This definition comes from prctl.h, but some kernels may not
 344          have it.  */
 345 #ifndef PTRACE_ARCH_PRCTL
 346 #define PTRACE_ARCH_PRCTL      30
 347 #endif
 348       /* FIXME: ezannoni-2003-07-09 see comment above about include
 349          file order.  We could be getting bogus values for these two.  */
 350       gdb_assert (FS < ELF_NGREG);
 351       gdb_assert (GS < ELF_NGREG);
 352       switch (idx)
 353         {
 354         case FS:
 355           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
 356             return PS_OK;
 357           break;
 358         case GS:
 359           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
 360             return PS_OK;
 361           break;
 362         default:                   /* Should not happen.  */
 363           return PS_BADADDR;
 364         }
 365     }
 366   return PS_ERR;               /* ptrace failed.  */
 367 }
 368 \f
 369
 370 static void (*super_post_startup_inferior) (ptid_t ptid);
 371
 372 static void
 373 amd64_linux_child_post_startup_inferior (ptid_t ptid)
 374 {
 375   i386_cleanup_dregs ();
 376   super_post_startup_inferior (ptid);
 377 }
 378 \f
 379
 380 /* Provide a prototype to silence -Wmissing-prototypes.  */
 381 void _initialize_amd64_linux_nat (void);
 382
 383 void
 384 _initialize_amd64_linux_nat (void)
 385 {
 386   struct target_ops *t;
 387
 388   amd64_native_gregset32_reg_offset = amd64_linux_gregset32_reg_offset;
 389   amd64_native_gregset32_num_regs = I386_LINUX_NUM_REGS;
 390   amd64_native_gregset64_reg_offset = amd64_linux_gregset64_reg_offset;
 391   amd64_native_gregset64_num_regs = AMD64_LINUX_NUM_REGS;
 392
 393   gdb_assert (ARRAY_SIZE (amd64_linux_gregset32_reg_offset)
 394               == amd64_native_gregset32_num_regs);
 395   gdb_assert (ARRAY_SIZE (amd64_linux_gregset64_reg_offset)
 396               == amd64_native_gregset64_num_regs);
 397
 398   /* Fill in the generic GNU/Linux methods.  */
 399   t = linux_target ();
 400
 401   /* Override the GNU/Linux inferior startup hook.  */
 402   super_post_startup_inferior = t->to_post_startup_inferior;
 403   t->to_post_startup_inferior = amd64_linux_child_post_startup_inferior;
 404
 405   /* Add our register access methods.  */
 406   t->to_fetch_registers = amd64_linux_fetch_inferior_registers;
 407   t->to_store_registers = amd64_linux_store_inferior_registers;
 408
 409   /* Register the target.  */
 410   linux_nat_add_target (t);
 411 }