sysdeps/i386/nptl/tls.h

   1 /* Definition for thread-local data handling.  nptl/i386 version.
   2    Copyright (C) 2002-2016 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 #include <dl-sysdep.h>
  23 #ifndef __ASSEMBLER__
  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 # include <dl-dtv.h>
  32
  33 typedef struct
  34 {
  35   void *tcb;            /* Pointer to the TCB.  Not necessarily the
  36                            thread descriptor used by libpthread.  */
  37   dtv_t *dtv;
  38   void *self;           /* Pointer to the thread descriptor.  */
  39   int multiple_threads;
  40   uintptr_t sysinfo;
  41   uintptr_t stack_guard;
  42   uintptr_t pointer_guard;
  43   int gscope_flag;
  44 #ifndef __ASSUME_PRIVATE_FUTEX
  45   int private_futex;
  46 #else
  47   int __glibc_reserved1;
  48 #endif
  49   /* Reservation of some values for the TM ABI.  */
  50   void *__private_tm[4];
  51   /* GCC split stack support.  */
  52   void *__private_ss;
  53 } tcbhead_t;
  54
  55 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  56
  57 #else /* __ASSEMBLER__ */
  58 # include <tcb-offsets.h>
  59 #endif
  60
  61
  62 /* Alignment requirement for the stack.  For IA-32 this is governed by
  63    the SSE memory functions.  */
  64 #define STACK_ALIGN     16
  65
  66 #ifndef __ASSEMBLER__
  67 /* Get system call information.  */
  68 # include <sysdep.h>
  69
  70 /* The old way: using LDT.  */
  71
  72 /* Structure passed to `modify_ldt', 'set_thread_area', and 'clone' calls.  */
  73 struct user_desc
  74 {
  75   unsigned int entry_number;
  76   unsigned long int base_addr;
  77   unsigned int limit;
  78   unsigned int seg_32bit:1;
  79   unsigned int contents:2;
  80   unsigned int read_exec_only:1;
  81   unsigned int limit_in_pages:1;
  82   unsigned int seg_not_present:1;
  83   unsigned int useable:1;
  84   unsigned int empty:25;
  85 };
  86
  87 /* Initializing bit fields is slow.  We speed it up by using a union.  */
  88 union user_desc_init
  89 {
  90   struct user_desc desc;
  91   unsigned int vals[4];
  92 };
  93
  94
  95 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
  96    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
  97    struct pthread even when not linked with -lpthread.  */
  98 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
  99
 100 /* Alignment requirements for the initial TCB.  */
 101 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 102
 103 /* This is the size of the TCB.  */
 104 # define TLS_TCB_SIZE sizeof (struct pthread)
 105
 106 /* Alignment requirements for the TCB.  */
 107 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 108
 109 /* The TCB can have any size and the memory following the address the
 110    thread pointer points to is unspecified.  Allocate the TCB there.  */
 111 # define TLS_TCB_AT_TP  1
 112 # define TLS_DTV_AT_TP  0
 113
 114 /* Get the thread descriptor definition.  */
 115 # include <nptl/descr.h>
 116
 117
 118 /* Install the dtv pointer.  The pointer passed is to the element with
 119    index -1 which contain the length.  */
 120 # define INSTALL_DTV(descr, dtvp) \
 121   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 122
 123 /* Install new dtv for current thread.  */
 124 # define INSTALL_NEW_DTV(dtvp) \
 125   ({ struct pthread *__pd;                                                    \
 126      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 127
 128 /* Return dtv of given thread descriptor.  */
 129 # define GET_DTV(descr) \
 130   (((tcbhead_t *) (descr))->dtv)
 131
 132 /* Macros to load from and store into segment registers.  */
 133 # ifndef TLS_GET_GS
 134 #  define TLS_GET_GS() \
 135   ({ int __seg; __asm ("movw %%gs, %w0" : "=q" (__seg)); __seg & 0xffff; })
 136 # endif
 137 # ifndef TLS_SET_GS
 138 #  define TLS_SET_GS(val) \
 139   __asm ("movw %w0, %%gs" :: "q" (val))
 140 # endif
 141
 142 #ifdef NEED_DL_SYSINFO
 143 # define INIT_SYSINFO \
 144   _head->sysinfo = GLRO(dl_sysinfo)
 145 # define SETUP_THREAD_SYSINFO(pd) \
 146   ((pd)->header.sysinfo = THREAD_GETMEM (THREAD_SELF, header.sysinfo))
 147 # define CHECK_THREAD_SYSINFO(pd) \
 148   assert ((pd)->header.sysinfo == THREAD_GETMEM (THREAD_SELF, header.sysinfo))
 149 #else
 150 # define INIT_SYSINFO
 151 #endif
 152
 153 #ifndef LOCK_PREFIX
 154 # ifdef UP
 155 #  define LOCK_PREFIX  /* nothing */
 156 # else
 157 #  define LOCK_PREFIX "lock;"
 158 # endif
 159 #endif
 160
 161 static inline void __attribute__ ((unused, always_inline))
 162 tls_fill_user_desc (union user_desc_init *desc,
 163                     unsigned int entry_number,
 164                     void *pd)
 165 {
 166   desc->vals[0] = entry_number;
 167   /* The 'base_addr' field.  Pointer to the TCB.  */
 168   desc->vals[1] = (unsigned long int) pd;
 169   /* The 'limit' field.  We use 4GB which is 0xfffff pages.  */
 170   desc->vals[2] = 0xfffff;
 171   /* Collapsed value of the bitfield:
 172      .seg_32bit = 1
 173      .contents = 0
 174      .read_exec_only = 0
 175      .limit_in_pages = 1
 176      .seg_not_present = 0
 177      .useable = 1 */
 178   desc->vals[3] = 0x51;
 179 }
 180
 181 /* Code to initially initialize the thread pointer.  This might need
 182    special attention since 'errno' is not yet available and if the
 183    operation can cause a failure 'errno' must not be touched.  */
 184 # define TLS_INIT_TP(thrdescr) \
 185   ({ void *_thrdescr = (thrdescr);                                            \
 186      tcbhead_t *_head = _thrdescr;                                            \
 187      union user_desc_init _segdescr;                                          \
 188      int _result;                                                             \
 189                                                                               \
 190      _head->tcb = _thrdescr;                                                  \
 191      /* For now the thread descriptor is at the same address.  */             \
 192      _head->self = _thrdescr;                                                 \
 193      /* New syscall handling support.  */                                     \
 194      INIT_SYSINFO;                                                            \
 195                                                                               \
 196      /* Let the kernel pick a value for the 'entry_number' field.  */         \
 197      tls_fill_user_desc (&_segdescr, -1, _thrdescr);                          \
 198                                                                               \
 199      /* Install the TLS.  */                                                  \
 200      INTERNAL_SYSCALL_DECL (err);                                             \
 201      _result = INTERNAL_SYSCALL (set_thread_area, err, 1, &_segdescr.desc);   \
 202                                                                               \
 203      if (_result == 0)                                                        \
 204        /* We know the index in the GDT, now load the segment register.        \
 205           The use of the GDT is described by the value 3 in the lower         \
 206           three bits of the segment descriptor value.                         \
 207                                                                               \
 208           Note that we have to do this even if the numeric value of           \
 209           the descriptor does not change.  Loading the segment register       \
 210           causes the segment information from the GDT to be loaded            \
 211           which is necessary since we have changed it.   */                   \
 212        TLS_SET_GS (_segdescr.desc.entry_number * 8 + 3);                      \
 213                                                                               \
 214      _result == 0 ? NULL                                                      \
 215      : "set_thread_area failed when setting up thread-local storage\n"; })
 216
 217 # define TLS_DEFINE_INIT_TP(tp, pd)                                           \
 218   union user_desc_init _segdescr;                                             \
 219   /* Find the 'entry_number' field that the kernel selected in TLS_INIT_TP.   \
 220      The first three bits of the segment register value select the GDT,       \
 221      ignore them.  We get the index from the value of the %gs register in     \
 222      the current thread.  */                                                  \
 223   tls_fill_user_desc (&_segdescr, TLS_GET_GS () >> 3, pd);                    \
 224   const struct user_desc *tp = &_segdescr.desc
 225
 226
 227 /* Return the address of the dtv for the current thread.  */
 228 # define THREAD_DTV() \
 229   ({ struct pthread *__pd;                                                    \
 230      THREAD_GETMEM (__pd, header.dtv); })
 231
 232
 233 /* Return the thread descriptor for the current thread.
 234
 235    The contained asm must *not* be marked volatile since otherwise
 236    assignments like
 237         pthread_descr self = thread_self();
 238    do not get optimized away.  */
 239 # define THREAD_SELF \
 240   ({ struct pthread *__self;                                                  \
 241      asm ("movl %%gs:%c1,%0" : "=r" (__self)                                  \
 242           : "i" (offsetof (struct pthread, header.self)));                    \
 243      __self;})
 244
 245 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 246 # define DB_THREAD_SELF \
 247   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 248   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 249
 250
 251 /* Read member of the thread descriptor directly.  */
 252 # define THREAD_GETMEM(descr, member) \
 253   ({ __typeof (descr->member) __value;                                        \
 254      if (sizeof (__value) == 1)                                               \
 255        asm volatile ("movb %%gs:%P2,%b0"                                      \
 256                      : "=q" (__value)                                         \
 257                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 258      else if (sizeof (__value) == 4)                                          \
 259        asm volatile ("movl %%gs:%P1,%0"                                       \
 260                      : "=r" (__value)                                         \
 261                      : "i" (offsetof (struct pthread, member)));              \
 262      else                                                                     \
 263        {                                                                      \
 264          if (sizeof (__value) != 8)                                           \
 265            /* There should not be any value with a size other than 1,         \
 266               4 or 8.  */                                                     \
 267            abort ();                                                          \
 268                                                                               \
 269          asm volatile ("movl %%gs:%P1,%%eax\n\t"                              \
 270                        "movl %%gs:%P2,%%edx"                                  \
 271                        : "=A" (__value)                                       \
 272                        : "i" (offsetof (struct pthread, member)),             \
 273                          "i" (offsetof (struct pthread, member) + 4));        \
 274        }                                                                      \
 275      __value; })
 276
 277
 278 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 279 # define THREAD_GETMEM_NC(descr, member, idx) \
 280   ({ __typeof (descr->member[0]) __value;                                     \
 281      if (sizeof (__value) == 1)                                               \
 282        asm volatile ("movb %%gs:%P2(%3),%b0"                                  \
 283                      : "=q" (__value)                                         \
 284                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 285                      "r" (idx));                                              \
 286      else if (sizeof (__value) == 4)                                          \
 287        asm volatile ("movl %%gs:%P1(,%2,4),%0"                                \
 288                      : "=r" (__value)                                         \
 289                      : "i" (offsetof (struct pthread, member[0])),            \
 290                        "r" (idx));                                            \
 291      else                                                                     \
 292        {                                                                      \
 293          if (sizeof (__value) != 8)                                           \
 294            /* There should not be any value with a size other than 1,         \
 295               4 or 8.  */                                                     \
 296            abort ();                                                          \
 297                                                                               \
 298          asm volatile  ("movl %%gs:%P1(,%2,8),%%eax\n\t"                      \
 299                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 300                         : "=&A" (__value)                                     \
 301                         : "i" (offsetof (struct pthread, member[0])),         \
 302                           "r" (idx));                                         \
 303        }                                                                      \
 304      __value; })
 305
 306
 307
 308 /* Set member of the thread descriptor directly.  */
 309 # define THREAD_SETMEM(descr, member, value) \
 310   ({ if (sizeof (descr->member) == 1)                                         \
 311        asm volatile ("movb %b0,%%gs:%P1" :                                    \
 312                      : "iq" (value),                                          \
 313                        "i" (offsetof (struct pthread, member)));              \
 314      else if (sizeof (descr->member) == 4)                                    \
 315        asm volatile ("movl %0,%%gs:%P1" :                                     \
 316                      : "ir" (value),                                          \
 317                        "i" (offsetof (struct pthread, member)));              \
 318      else                                                                     \
 319        {                                                                      \
 320          if (sizeof (descr->member) != 8)                                     \
 321            /* There should not be any value with a size other than 1,         \
 322               4 or 8.  */                                                     \
 323            abort ();                                                          \
 324                                                                               \
 325          asm volatile ("movl %%eax,%%gs:%P1\n\t"                              \
 326                        "movl %%edx,%%gs:%P2" :                                \
 327                        : "A" ((uint64_t) cast_to_integer (value)),            \
 328                          "i" (offsetof (struct pthread, member)),             \
 329                          "i" (offsetof (struct pthread, member) + 4));        \
 330        }})
 331
 332
 333 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 334 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 335   ({ if (sizeof (descr->member[0]) == 1)                                      \
 336        asm volatile ("movb %b0,%%gs:%P1(%2)" :                                \
 337                      : "iq" (value),                                          \
 338                        "i" (offsetof (struct pthread, member)),               \
 339                        "r" (idx));                                            \
 340      else if (sizeof (descr->member[0]) == 4)                                 \
 341        asm volatile ("movl %0,%%gs:%P1(,%2,4)" :                              \
 342                      : "ir" (value),                                          \
 343                        "i" (offsetof (struct pthread, member)),               \
 344                        "r" (idx));                                            \
 345      else                                                                     \
 346        {                                                                      \
 347          if (sizeof (descr->member[0]) != 8)                                  \
 348            /* There should not be any value with a size other than 1,         \
 349               4 or 8.  */                                                     \
 350            abort ();                                                          \
 351                                                                               \
 352          asm volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                       \
 353                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 354                        : "A" ((uint64_t) cast_to_integer (value)),            \
 355                          "i" (offsetof (struct pthread, member)),             \
 356                          "r" (idx));                                          \
 357        }})
 358
 359
 360 /* Atomic compare and exchange on TLS, returning old value.  */
 361 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 362   ({ __typeof (descr->member) __ret;                                          \
 363      __typeof (oldval) __old = (oldval);                                      \
 364      if (sizeof (descr->member) == 4)                                         \
 365        asm volatile (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                      \
 366                      : "=a" (__ret)                                           \
 367                      : "0" (__old), "r" (newval),                             \
 368                        "i" (offsetof (struct pthread, member)));              \
 369      else                                                                     \
 370        /* Not necessary for other sizes in the moment.  */                    \
 371        abort ();                                                              \
 372      __ret; })
 373
 374
 375 /* Atomic logical and.  */
 376 #define THREAD_ATOMIC_AND(descr, member, val) \
 377   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 378               asm volatile (LOCK_PREFIX "andl %1, %%gs:%P0"                   \
 379                             :: "i" (offsetof (struct pthread, member)),       \
 380                                "ir" (val));                                   \
 381             else                                                              \
 382               /* Not necessary for other sizes in the moment.  */             \
 383               abort (); })
 384
 385
 386 /* Atomic set bit.  */
 387 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 388   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 389               asm volatile (LOCK_PREFIX "orl %1, %%gs:%P0"                    \
 390                             :: "i" (offsetof (struct pthread, member)),       \
 391                                "ir" (1 << (bit)));                            \
 392             else                                                              \
 393               /* Not necessary for other sizes in the moment.  */             \
 394               abort (); })
 395
 396
 397 /* Call the user-provided thread function.  */
 398 #define CALL_THREAD_FCT(descr) \
 399   ({ void *__res;                                                             \
 400      int __ignore1, __ignore2;                                                \
 401      asm volatile ("pushl %%eax\n\t"                                          \
 402                    "pushl %%eax\n\t"                                          \
 403                    "pushl %%eax\n\t"                                          \
 404                    "pushl %%gs:%P4\n\t"                                       \
 405                    "call *%%gs:%P3\n\t"                                       \
 406                    "addl $16, %%esp"                                          \
 407                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 408                    : "i" (offsetof (struct pthread, start_routine)),          \
 409                      "i" (offsetof (struct pthread, arg)));                   \
 410      __res; })
 411
 412
 413 /* Set the stack guard field in TCB head.  */
 414 #define THREAD_SET_STACK_GUARD(value) \
 415   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 416 #define THREAD_COPY_STACK_GUARD(descr) \
 417   ((descr)->header.stack_guard                                                \
 418    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 419
 420
 421 /* Set the pointer guard field in the TCB head.  */
 422 #define THREAD_SET_POINTER_GUARD(value) \
 423   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 424 #define THREAD_COPY_POINTER_GUARD(descr) \
 425   ((descr)->header.pointer_guard                                              \
 426    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 427
 428
 429 /* Get and set the global scope generation counter in the TCB head.  */
 430 #define THREAD_GSCOPE_FLAG_UNUSED 0
 431 #define THREAD_GSCOPE_FLAG_USED   1
 432 #define THREAD_GSCOPE_FLAG_WAIT   2
 433 #define THREAD_GSCOPE_RESET_FLAG() \
 434   do                                                                          \
 435     { int __res;                                                              \
 436       asm volatile ("xchgl %0, %%gs:%P1"                                      \
 437                     : "=r" (__res)                                            \
 438                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 439                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 440       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 441         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
 442     }                                                                         \
 443   while (0)
 444 #define THREAD_GSCOPE_SET_FLAG() \
 445   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 446 #define THREAD_GSCOPE_WAIT() \
 447   GL(dl_wait_lookup_done) ()
 448
 449 #endif /* __ASSEMBLER__ */
 450
 451 #endif  /* tls.h */