sysdeps/x86_64/nptl/tls.h

   1 /* Definition for thread-local data handling.  nptl/x86_64 version.
   2    Copyright (C) 2002-2015 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _TLS_H
  20 #define _TLS_H  1
  21
  22 #ifndef __ASSEMBLER__
  23 # include <asm/prctl.h> /* For ARCH_SET_FS.  */
  24 # include <stdbool.h>
  25 # include <stddef.h>
  26 # include <stdint.h>
  27 # include <stdlib.h>
  28 # include <sysdep.h>
  29 # include <libc-internal.h>
  30 # include <kernel-features.h>
  31
  32 /* Replacement type for __m128 since this file is included by ld.so,
  33    which is compiled with -mno-sse.  It must not change the alignment
  34    of rtld_savespace_sse.  */
  35 typedef struct
  36 {
  37   int i[4];
  38 } __128bits;
  39
  40
  41 /* Type for the dtv.  */
  42 typedef union dtv
  43 {
  44   size_t counter;
  45   struct
  46   {
  47     void *val;
  48     bool is_static;
  49   } pointer;
  50 } dtv_t;
  51
  52
  53 typedef struct
  54 {
  55   void *tcb;            /* Pointer to the TCB.  Not necessarily the
  56                            thread descriptor used by libpthread.  */
  57   dtv_t *dtv;
  58   void *self;           /* Pointer to the thread descriptor.  */
  59   int multiple_threads;
  60   int gscope_flag;
  61   uintptr_t sysinfo;
  62   uintptr_t stack_guard;
  63   uintptr_t pointer_guard;
  64   unsigned long int vgetcpu_cache[2];
  65 # ifndef __ASSUME_PRIVATE_FUTEX
  66   int private_futex;
  67 # else
  68   int __glibc_reserved1;
  69 # endif
  70   int rtld_must_xmm_save;
  71   /* Reservation of some values for the TM ABI.  */
  72   void *__private_tm[4];
  73   /* GCC split stack support.  */
  74   void *__private_ss;
  75   long int __glibc_reserved2;
  76   /* Have space for the post-AVX register size.  */
  77   __128bits rtld_savespace_sse[8][4] __attribute__ ((aligned (32)));
  78
  79   void *__padding[8];
  80 } tcbhead_t;
  81
  82 #else /* __ASSEMBLER__ */
  83 # include <tcb-offsets.h>
  84 #endif
  85
  86
  87 /* Alignment requirement for the stack.  */
  88 #define STACK_ALIGN     16
  89
  90
  91 #ifndef __ASSEMBLER__
  92 /* Get system call information.  */
  93 # include <sysdep.h>
  94
  95 #ifndef LOCK_PREFIX
  96 # ifdef UP
  97 #  define LOCK_PREFIX   /* nothing */
  98 # else
  99 #  define LOCK_PREFIX   "lock;"
 100 # endif
 101 #endif
 102
 103 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
 104    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
 105    struct pthread even when not linked with -lpthread.  */
 106 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
 107
 108 /* Alignment requirements for the initial TCB.  */
 109 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 110
 111 /* This is the size of the TCB.  */
 112 # define TLS_TCB_SIZE sizeof (struct pthread)
 113
 114 /* Alignment requirements for the TCB.  */
 115 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 116
 117 /* The TCB can have any size and the memory following the address the
 118    thread pointer points to is unspecified.  Allocate the TCB there.  */
 119 # define TLS_TCB_AT_TP  1
 120 # define TLS_DTV_AT_TP  0
 121
 122 /* Get the thread descriptor definition.  */
 123 # include <nptl/descr.h>
 124
 125
 126 /* Install the dtv pointer.  The pointer passed is to the element with
 127    index -1 which contain the length.  */
 128 # define INSTALL_DTV(descr, dtvp) \
 129   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 130
 131 /* Install new dtv for current thread.  */
 132 # define INSTALL_NEW_DTV(dtvp) \
 133   ({ struct pthread *__pd;                                                    \
 134      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 135
 136 /* Return dtv of given thread descriptor.  */
 137 # define GET_DTV(descr) \
 138   (((tcbhead_t *) (descr))->dtv)
 139
 140
 141 /* Code to initially initialize the thread pointer.  This might need
 142    special attention since 'errno' is not yet available and if the
 143    operation can cause a failure 'errno' must not be touched.
 144
 145    We have to make the syscall for both uses of the macro since the
 146    address might be (and probably is) different.  */
 147 # define TLS_INIT_TP(thrdescr) \
 148   ({ void *_thrdescr = (thrdescr);                                            \
 149      tcbhead_t *_head = _thrdescr;                                            \
 150      int _result;                                                             \
 151                                                                               \
 152      _head->tcb = _thrdescr;                                                  \
 153      /* For now the thread descriptor is at the same address.  */             \
 154      _head->self = _thrdescr;                                                 \
 155                                                                               \
 156      /* It is a simple syscall to set the %fs value for the thread.  */       \
 157      asm volatile ("syscall"                                                  \
 158                    : "=a" (_result)                                           \
 159                    : "0" ((unsigned long int) __NR_arch_prctl),               \
 160                      "D" ((unsigned long int) ARCH_SET_FS),                   \
 161                      "S" (_thrdescr)                                          \
 162                    : "memory", "cc", "r11", "cx");                            \
 163                                                                               \
 164     _result ? "cannot set %fs base address for thread-local storage" : 0;     \
 165   })
 166
 167 # define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd)
 168
 169
 170 /* Return the address of the dtv for the current thread.  */
 171 # define THREAD_DTV() \
 172   ({ struct pthread *__pd;                                                    \
 173      THREAD_GETMEM (__pd, header.dtv); })
 174
 175
 176 /* Return the thread descriptor for the current thread.
 177
 178    The contained asm must *not* be marked volatile since otherwise
 179    assignments like
 180         pthread_descr self = thread_self();
 181    do not get optimized away.  */
 182 # define THREAD_SELF \
 183   ({ struct pthread *__self;                                                  \
 184      asm ("mov %%fs:%c1,%0" : "=r" (__self)                                   \
 185           : "i" (offsetof (struct pthread, header.self)));                    \
 186      __self;})
 187
 188 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 189 # define DB_THREAD_SELF_INCLUDE  <sys/reg.h> /* For the FS constant.  */
 190 # define DB_THREAD_SELF CONST_THREAD_AREA (64, FS)
 191
 192 /* Read member of the thread descriptor directly.  */
 193 # define THREAD_GETMEM(descr, member) \
 194   ({ __typeof (descr->member) __value;                                        \
 195      if (sizeof (__value) == 1)                                               \
 196        asm volatile ("movb %%fs:%P2,%b0"                                      \
 197                      : "=q" (__value)                                         \
 198                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 199      else if (sizeof (__value) == 4)                                          \
 200        asm volatile ("movl %%fs:%P1,%0"                                       \
 201                      : "=r" (__value)                                         \
 202                      : "i" (offsetof (struct pthread, member)));              \
 203      else                                                                     \
 204        {                                                                      \
 205          if (sizeof (__value) != 8)                                           \
 206            /* There should not be any value with a size other than 1,         \
 207               4 or 8.  */                                                     \
 208            abort ();                                                          \
 209                                                                               \
 210          asm volatile ("movq %%fs:%P1,%q0"                                    \
 211                        : "=r" (__value)                                       \
 212                        : "i" (offsetof (struct pthread, member)));            \
 213        }                                                                      \
 214      __value; })
 215
 216
 217 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 218 # define THREAD_GETMEM_NC(descr, member, idx) \
 219   ({ __typeof (descr->member[0]) __value;                                     \
 220      if (sizeof (__value) == 1)                                               \
 221        asm volatile ("movb %%fs:%P2(%q3),%b0"                                 \
 222                      : "=q" (__value)                                         \
 223                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 224                        "r" (idx));                                            \
 225      else if (sizeof (__value) == 4)                                          \
 226        asm volatile ("movl %%fs:%P1(,%q2,4),%0"                               \
 227                      : "=r" (__value)                                         \
 228                      : "i" (offsetof (struct pthread, member[0])), "r" (idx));\
 229      else                                                                     \
 230        {                                                                      \
 231          if (sizeof (__value) != 8)                                           \
 232            /* There should not be any value with a size other than 1,         \
 233               4 or 8.  */                                                     \
 234            abort ();                                                          \
 235                                                                               \
 236          asm volatile ("movq %%fs:%P1(,%q2,8),%q0"                            \
 237                        : "=r" (__value)                                       \
 238                        : "i" (offsetof (struct pthread, member[0])),          \
 239                          "r" (idx));                                          \
 240        }                                                                      \
 241      __value; })
 242
 243
 244 /* Loading addresses of objects on x86-64 needs to be treated special
 245    when generating PIC code.  */
 246 #ifdef __pic__
 247 # define IMM_MODE "nr"
 248 #else
 249 # define IMM_MODE "ir"
 250 #endif
 251
 252
 253 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 254 # define THREAD_SETMEM(descr, member, value) \
 255   ({ if (sizeof (descr->member) == 1)                                         \
 256        asm volatile ("movb %b0,%%fs:%P1" :                                    \
 257                      : "iq" (value),                                          \
 258                        "i" (offsetof (struct pthread, member)));              \
 259      else if (sizeof (descr->member) == 4)                                    \
 260        asm volatile ("movl %0,%%fs:%P1" :                                     \
 261                      : IMM_MODE (value),                                      \
 262                        "i" (offsetof (struct pthread, member)));              \
 263      else                                                                     \
 264        {                                                                      \
 265          if (sizeof (descr->member) != 8)                                     \
 266            /* There should not be any value with a size other than 1,         \
 267               4 or 8.  */                                                     \
 268            abort ();                                                          \
 269                                                                               \
 270          asm volatile ("movq %q0,%%fs:%P1" :                                  \
 271                        : IMM_MODE ((uint64_t) cast_to_integer (value)),       \
 272                          "i" (offsetof (struct pthread, member)));            \
 273        }})
 274
 275
 276 /* Set member of the thread descriptor directly.  */
 277 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 278   ({ if (sizeof (descr->member[0]) == 1)                                      \
 279        asm volatile ("movb %b0,%%fs:%P1(%q2)" :                               \
 280                      : "iq" (value),                                          \
 281                        "i" (offsetof (struct pthread, member[0])),            \
 282                        "r" (idx));                                            \
 283      else if (sizeof (descr->member[0]) == 4)                                 \
 284        asm volatile ("movl %0,%%fs:%P1(,%q2,4)" :                             \
 285                      : IMM_MODE (value),                                      \
 286                        "i" (offsetof (struct pthread, member[0])),            \
 287                        "r" (idx));                                            \
 288      else                                                                     \
 289        {                                                                      \
 290          if (sizeof (descr->member[0]) != 8)                                  \
 291            /* There should not be any value with a size other than 1,         \
 292               4 or 8.  */                                                     \
 293            abort ();                                                          \
 294                                                                               \
 295          asm volatile ("movq %q0,%%fs:%P1(,%q2,8)" :                          \
 296                        : IMM_MODE ((uint64_t) cast_to_integer (value)),       \
 297                          "i" (offsetof (struct pthread, member[0])),          \
 298                          "r" (idx));                                          \
 299        }})
 300
 301
 302 /* Atomic compare and exchange on TLS, returning old value.  */
 303 # define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 304   ({ __typeof (descr->member) __ret;                                          \
 305      __typeof (oldval) __old = (oldval);                                      \
 306      if (sizeof (descr->member) == 4)                                         \
 307        asm volatile (LOCK_PREFIX "cmpxchgl %2, %%fs:%P3"                      \
 308                      : "=a" (__ret)                                           \
 309                      : "0" (__old), "r" (newval),                             \
 310                        "i" (offsetof (struct pthread, member)));              \
 311      else                                                                     \
 312        /* Not necessary for other sizes in the moment.  */                    \
 313        abort ();                                                              \
 314      __ret; })
 315
 316
 317 /* Atomic logical and.  */
 318 # define THREAD_ATOMIC_AND(descr, member, val) \
 319   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 320               asm volatile (LOCK_PREFIX "andl %1, %%fs:%P0"                   \
 321                             :: "i" (offsetof (struct pthread, member)),       \
 322                                "ir" (val));                                   \
 323             else                                                              \
 324               /* Not necessary for other sizes in the moment.  */             \
 325               abort (); })
 326
 327
 328 /* Atomic set bit.  */
 329 # define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 330   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 331               asm volatile (LOCK_PREFIX "orl %1, %%fs:%P0"                    \
 332                             :: "i" (offsetof (struct pthread, member)),       \
 333                                "ir" (1 << (bit)));                            \
 334             else                                                              \
 335               /* Not necessary for other sizes in the moment.  */             \
 336               abort (); })
 337
 338
 339 # define CALL_THREAD_FCT(descr) \
 340   ({ void *__res;                                                             \
 341      asm volatile ("movq %%fs:%P2, %%rdi\n\t"                                 \
 342                    "callq *%%fs:%P1"                                          \
 343                    : "=a" (__res)                                             \
 344                    : "i" (offsetof (struct pthread, start_routine)),          \
 345                      "i" (offsetof (struct pthread, arg))                     \
 346                    : "di", "si", "cx", "dx", "r8", "r9", "r10", "r11",        \
 347                      "memory", "cc");                                         \
 348      __res; })
 349
 350
 351 /* Set the stack guard field in TCB head.  */
 352 # define THREAD_SET_STACK_GUARD(value) \
 353     THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 354 # define THREAD_COPY_STACK_GUARD(descr) \
 355     ((descr)->header.stack_guard                                              \
 356      = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 357
 358
 359 /* Set the pointer guard field in the TCB head.  */
 360 # define THREAD_SET_POINTER_GUARD(value) \
 361   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 362 # define THREAD_COPY_POINTER_GUARD(descr) \
 363   ((descr)->header.pointer_guard                                              \
 364    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 365
 366
 367 /* Get and set the global scope generation counter in the TCB head.  */
 368 # define THREAD_GSCOPE_FLAG_UNUSED 0
 369 # define THREAD_GSCOPE_FLAG_USED   1
 370 # define THREAD_GSCOPE_FLAG_WAIT   2
 371 # define THREAD_GSCOPE_RESET_FLAG() \
 372   do                                                                          \
 373     { int __res;                                                              \
 374       asm volatile ("xchgl %0, %%fs:%P1"                                      \
 375                     : "=r" (__res)                                            \
 376                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 377                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 378       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 379         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
 380     }                                                                         \
 381   while (0)
 382 # define THREAD_GSCOPE_SET_FLAG() \
 383   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 384 # define THREAD_GSCOPE_WAIT() \
 385   GL(dl_wait_lookup_done) ()
 386
 387
 388 # ifdef SHARED
 389 /* Defined in dl-trampoline.S.  */
 390 extern void _dl_x86_64_save_sse (void);
 391 extern void _dl_x86_64_restore_sse (void);
 392
 393 # define RTLD_CHECK_FOREIGN_CALL \
 394   (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save) != 0)
 395
 396 /* NB: Don't use the xchg operation because that would imply a lock
 397    prefix which is expensive and unnecessary.  The cache line is also
 398    not contested at all.  */
 399 #  define RTLD_ENABLE_FOREIGN_CALL \
 400   int old_rtld_must_xmm_save = THREAD_GETMEM (THREAD_SELF,                    \
 401                                               header.rtld_must_xmm_save);     \
 402   THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, 1)
 403
 404 #  define RTLD_PREPARE_FOREIGN_CALL \
 405   do if (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save))              \
 406     {                                                                         \
 407       _dl_x86_64_save_sse ();                                                 \
 408       THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save, 0);              \
 409     }                                                                         \
 410   while (0)
 411
 412 #  define RTLD_FINALIZE_FOREIGN_CALL \
 413   do {                                                                        \
 414     if (THREAD_GETMEM (THREAD_SELF, header.rtld_must_xmm_save) == 0)          \
 415       _dl_x86_64_restore_sse ();                                              \
 416     THREAD_SETMEM (THREAD_SELF, header.rtld_must_xmm_save,                    \
 417                    old_rtld_must_xmm_save);                                   \
 418   } while (0)
 419 # endif
 420
 421
 422 #endif /* __ASSEMBLER__ */
 423
 424 #endif  /* tls.h */