nptl/sysdeps/i386/tls.h

   1 /* Definition for thread-local data handling.  nptl/i386 version.
   2    Copyright (C) 2002,2003,2004,2005,2007 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _TLS_H
  21 #define _TLS_H  1
  22
  23 #include <dl-sysdep.h>
  24 #ifndef __ASSEMBLER__
  25 # include <stdbool.h>
  26 # include <stddef.h>
  27 # include <stdint.h>
  28 # include <stdlib.h>
  29 # include <list.h>
  30
  31
  32 /* Type for the dtv.  */
  33 typedef union dtv
  34 {
  35   size_t counter;
  36   struct
  37   {
  38     void *val;
  39     bool is_static;
  40   } pointer;
  41 } dtv_t;
  42
  43
  44 typedef struct
  45 {
  46   void *tcb;            /* Pointer to the TCB.  Not necessarily the
  47                            thread descriptor used by libpthread.  */
  48   dtv_t *dtv;
  49   void *self;           /* Pointer to the thread descriptor.  */
  50   int multiple_threads;
  51   uintptr_t sysinfo;
  52   uintptr_t stack_guard;
  53   uintptr_t pointer_guard;
  54   int gscope_flag;
  55 } tcbhead_t;
  56
  57 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  58
  59 #else /* __ASSEMBLER__ */
  60 # include <tcb-offsets.h>
  61 #endif
  62
  63
  64 /* We require TLS support in the tools.  */
  65 #ifndef HAVE_TLS_SUPPORT
  66 # error "TLS support is required."
  67 #endif
  68
  69 /* Signal that TLS support is available.  */
  70 #define USE_TLS 1
  71
  72 /* Alignment requirement for the stack.  For IA-32 this is governed by
  73    the SSE memory functions.  */
  74 #define STACK_ALIGN     16
  75
  76 #ifndef __ASSEMBLER__
  77 /* Get system call information.  */
  78 # include <sysdep.h>
  79
  80 /* The old way: using LDT.  */
  81
  82 /* Structure passed to `modify_ldt', 'set_thread_area', and 'clone' calls.  */
  83 struct user_desc
  84 {
  85   unsigned int entry_number;
  86   unsigned long int base_addr;
  87   unsigned int limit;
  88   unsigned int seg_32bit:1;
  89   unsigned int contents:2;
  90   unsigned int read_exec_only:1;
  91   unsigned int limit_in_pages:1;
  92   unsigned int seg_not_present:1;
  93   unsigned int useable:1;
  94   unsigned int empty:25;
  95 };
  96
  97 /* Initializing bit fields is slow.  We speed it up by using a union.  */
  98 union user_desc_init
  99 {
 100   struct user_desc desc;
 101   unsigned int vals[4];
 102 };
 103
 104
 105 /* Get the thread descriptor definition.  */
 106 # include <nptl/descr.h>
 107
 108 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
 109    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
 110    struct pthread even when not linked with -lpthread.  */
 111 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
 112
 113 /* Alignment requirements for the initial TCB.  */
 114 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 115
 116 /* This is the size of the TCB.  */
 117 # define TLS_TCB_SIZE sizeof (struct pthread)
 118
 119 /* Alignment requirements for the TCB.  */
 120 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 121
 122 /* The TCB can have any size and the memory following the address the
 123    thread pointer points to is unspecified.  Allocate the TCB there.  */
 124 # define TLS_TCB_AT_TP  1
 125
 126
 127 /* Install the dtv pointer.  The pointer passed is to the element with
 128    index -1 which contain the length.  */
 129 # define INSTALL_DTV(descr, dtvp) \
 130   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 131
 132 /* Install new dtv for current thread.  */
 133 # define INSTALL_NEW_DTV(dtvp) \
 134   ({ struct pthread *__pd;                                                    \
 135      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 136
 137 /* Return dtv of given thread descriptor.  */
 138 # define GET_DTV(descr) \
 139   (((tcbhead_t *) (descr))->dtv)
 140
 141 #define THREAD_SELF_SYSINFO     THREAD_GETMEM (THREAD_SELF, header.sysinfo)
 142 #define THREAD_SYSINFO(pd)      ((pd)->header.sysinfo)
 143
 144 /* Macros to load from and store into segment registers.  */
 145 # ifndef TLS_GET_GS
 146 #  define TLS_GET_GS() \
 147   ({ int __seg; __asm ("movw %%gs, %w0" : "=q" (__seg)); __seg & 0xffff; })
 148 # endif
 149 # ifndef TLS_SET_GS
 150 #  define TLS_SET_GS(val) \
 151   __asm ("movw %w0, %%gs" :: "q" (val))
 152 # endif
 153
 154
 155 # ifndef __NR_set_thread_area
 156 #  define __NR_set_thread_area 243
 157 # endif
 158 # ifndef TLS_FLAG_WRITABLE
 159 #  define TLS_FLAG_WRITABLE             0x00000001
 160 # endif
 161
 162 // XXX Enable for the real world.
 163 #if 0
 164 # ifndef __ASSUME_SET_THREAD_AREA
 165 #  error "we need set_thread_area"
 166 # endif
 167 #endif
 168
 169 # ifdef __PIC__
 170 #  define TLS_EBX_ARG "r"
 171 #  define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
 172 # else
 173 #  define TLS_EBX_ARG "b"
 174 #  define TLS_LOAD_EBX
 175 # endif
 176
 177 #if defined NEED_DL_SYSINFO
 178 # define INIT_SYSINFO \
 179   _head->sysinfo = GLRO(dl_sysinfo)
 180 #else
 181 # define INIT_SYSINFO
 182 #endif
 183
 184 #ifndef LOCK_PREFIX
 185 # ifdef UP
 186 #  define LOCK_PREFIX  /* nothing */
 187 # else
 188 #  define LOCK_PREFIX "lock;"
 189 # endif
 190 #endif
 191
 192 /* Code to initially initialize the thread pointer.  This might need
 193    special attention since 'errno' is not yet available and if the
 194    operation can cause a failure 'errno' must not be touched.  */
 195 # define TLS_INIT_TP(thrdescr, secondcall) \
 196   ({ void *_thrdescr = (thrdescr);                                            \
 197      tcbhead_t *_head = _thrdescr;                                            \
 198      union user_desc_init _segdescr;                                          \
 199      int _result;                                                             \
 200                                                                               \
 201      _head->tcb = _thrdescr;                                                  \
 202      /* For now the thread descriptor is at the same address.  */             \
 203      _head->self = _thrdescr;                                                 \
 204      /* New syscall handling support.  */                                     \
 205      INIT_SYSINFO;                                                            \
 206                                                                               \
 207      /* The 'entry_number' field.  Let the kernel pick a value.  */           \
 208      if (secondcall)                                                          \
 209        _segdescr.vals[0] = TLS_GET_GS () >> 3;                                \
 210      else                                                                     \
 211        _segdescr.vals[0] = -1;                                                \
 212      /* The 'base_addr' field.  Pointer to the TCB.  */                       \
 213      _segdescr.vals[1] = (unsigned long int) _thrdescr;                       \
 214      /* The 'limit' field.  We use 4GB which is 0xfffff pages.  */            \
 215      _segdescr.vals[2] = 0xfffff;                                             \
 216      /* Collapsed value of the bitfield:                                      \
 217           .seg_32bit = 1                                                      \
 218           .contents = 0                                                       \
 219           .read_exec_only = 0                                                 \
 220           .limit_in_pages = 1                                                 \
 221           .seg_not_present = 0                                                \
 222           .useable = 1 */                                                     \
 223      _segdescr.vals[3] = 0x51;                                                \
 224                                                                               \
 225      /* Install the TLS.  */                                                  \
 226      asm volatile (TLS_LOAD_EBX                                               \
 227                    "int $0x80\n\t"                                            \
 228                    TLS_LOAD_EBX                                               \
 229                    : "=a" (_result), "=m" (_segdescr.desc.entry_number)       \
 230                    : "0" (__NR_set_thread_area),                              \
 231                      TLS_EBX_ARG (&_segdescr.desc), "m" (_segdescr.desc));    \
 232                                                                               \
 233      if (_result == 0)                                                        \
 234        /* We know the index in the GDT, now load the segment register.        \
 235           The use of the GDT is described by the value 3 in the lower         \
 236           three bits of the segment descriptor value.                         \
 237                                                                               \
 238           Note that we have to do this even if the numeric value of           \
 239           the descriptor does not change.  Loading the segment register       \
 240           causes the segment information from the GDT to be loaded            \
 241           which is necessary since we have changed it.   */                   \
 242        TLS_SET_GS (_segdescr.desc.entry_number * 8 + 3);                      \
 243                                                                               \
 244      _result == 0 ? NULL                                                      \
 245      : "set_thread_area failed when setting up thread-local storage\n"; })
 246
 247
 248 /* Return the address of the dtv for the current thread.  */
 249 # define THREAD_DTV() \
 250   ({ struct pthread *__pd;                                                    \
 251      THREAD_GETMEM (__pd, header.dtv); })
 252
 253
 254 /* Return the thread descriptor for the current thread.
 255
 256    The contained asm must *not* be marked volatile since otherwise
 257    assignments like
 258         pthread_descr self = thread_self();
 259    do not get optimized away.  */
 260 # define THREAD_SELF \
 261   ({ struct pthread *__self;                                                  \
 262      asm ("movl %%gs:%c1,%0" : "=r" (__self)                                  \
 263           : "i" (offsetof (struct pthread, header.self)));                    \
 264      __self;})
 265
 266 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 267 # define DB_THREAD_SELF \
 268   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 269   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 270
 271
 272 /* Read member of the thread descriptor directly.  */
 273 # define THREAD_GETMEM(descr, member) \
 274   ({ __typeof (descr->member) __value;                                        \
 275      if (sizeof (__value) == 1)                                               \
 276        asm volatile ("movb %%gs:%P2,%b0"                                      \
 277                      : "=q" (__value)                                         \
 278                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 279      else if (sizeof (__value) == 4)                                          \
 280        asm volatile ("movl %%gs:%P1,%0"                                       \
 281                      : "=r" (__value)                                         \
 282                      : "i" (offsetof (struct pthread, member)));              \
 283      else                                                                     \
 284        {                                                                      \
 285          if (sizeof (__value) != 8)                                           \
 286            /* There should not be any value with a size other than 1,         \
 287               4 or 8.  */                                                     \
 288            abort ();                                                          \
 289                                                                               \
 290          asm volatile ("movl %%gs:%P1,%%eax\n\t"                              \
 291                        "movl %%gs:%P2,%%edx"                                  \
 292                        : "=A" (__value)                                       \
 293                        : "i" (offsetof (struct pthread, member)),             \
 294                          "i" (offsetof (struct pthread, member) + 4));        \
 295        }                                                                      \
 296      __value; })
 297
 298
 299 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 300 # define THREAD_GETMEM_NC(descr, member, idx) \
 301   ({ __typeof (descr->member[0]) __value;                                     \
 302      if (sizeof (__value) == 1)                                               \
 303        asm volatile ("movb %%gs:%P2(%3),%b0"                                  \
 304                      : "=q" (__value)                                         \
 305                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 306                      "r" (idx));                                              \
 307      else if (sizeof (__value) == 4)                                          \
 308        asm volatile ("movl %%gs:%P1(,%2,4),%0"                                \
 309                      : "=r" (__value)                                         \
 310                      : "i" (offsetof (struct pthread, member[0])),            \
 311                        "r" (idx));                                            \
 312      else                                                                     \
 313        {                                                                      \
 314          if (sizeof (__value) != 8)                                           \
 315            /* There should not be any value with a size other than 1,         \
 316               4 or 8.  */                                                     \
 317            abort ();                                                          \
 318                                                                               \
 319          asm volatile  ("movl %%gs:%P1(,%2,8),%%eax\n\t"                      \
 320                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 321                         : "=&A" (__value)                                     \
 322                         : "i" (offsetof (struct pthread, member[0])),         \
 323                           "r" (idx));                                         \
 324        }                                                                      \
 325      __value; })
 326
 327
 328 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 329 # define THREAD_SETMEM(descr, member, value) \
 330   ({ if (sizeof (descr->member) == 1)                                         \
 331        asm volatile ("movb %b0,%%gs:%P1" :                                    \
 332                      : "iq" (value),                                          \
 333                        "i" (offsetof (struct pthread, member)));              \
 334      else if (sizeof (descr->member) == 4)                                    \
 335        asm volatile ("movl %0,%%gs:%P1" :                                     \
 336                      : "ir" (value),                                          \
 337                        "i" (offsetof (struct pthread, member)));              \
 338      else                                                                     \
 339        {                                                                      \
 340          if (sizeof (descr->member) != 8)                                     \
 341            /* There should not be any value with a size other than 1,         \
 342               4 or 8.  */                                                     \
 343            abort ();                                                          \
 344                                                                               \
 345          asm volatile ("movl %%eax,%%gs:%P1\n\t"                              \
 346                        "movl %%edx,%%gs:%P2" :                                \
 347                        : "A" (value),                                         \
 348                          "i" (offsetof (struct pthread, member)),             \
 349                          "i" (offsetof (struct pthread, member) + 4));        \
 350        }})
 351
 352
 353 /* Set member of the thread descriptor directly.  */
 354 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 355   ({ if (sizeof (descr->member[0]) == 1)                                      \
 356        asm volatile ("movb %b0,%%gs:%P1(%2)" :                                \
 357                      : "iq" (value),                                          \
 358                        "i" (offsetof (struct pthread, member)),               \
 359                        "r" (idx));                                            \
 360      else if (sizeof (descr->member[0]) == 4)                                 \
 361        asm volatile ("movl %0,%%gs:%P1(,%2,4)" :                              \
 362                      : "ir" (value),                                          \
 363                        "i" (offsetof (struct pthread, member)),               \
 364                        "r" (idx));                                            \
 365      else                                                                     \
 366        {                                                                      \
 367          if (sizeof (descr->member[0]) != 8)                                  \
 368            /* There should not be any value with a size other than 1,         \
 369               4 or 8.  */                                                     \
 370            abort ();                                                          \
 371                                                                               \
 372          asm volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                       \
 373                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 374                        : "A" (value),                                         \
 375                          "i" (offsetof (struct pthread, member)),             \
 376                          "r" (idx));                                          \
 377        }})
 378
 379
 380 /* Atomic compare and exchange on TLS, returning old value.  */
 381 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 382   ({ __typeof (descr->member) __ret;                                          \
 383      __typeof (oldval) __old = (oldval);                                      \
 384      if (sizeof (descr->member) == 4)                                         \
 385        asm volatile (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                      \
 386                      : "=a" (__ret)                                           \
 387                      : "0" (__old), "r" (newval),                             \
 388                        "i" (offsetof (struct pthread, member)));              \
 389      else                                                                     \
 390        /* Not necessary for other sizes in the moment.  */                    \
 391        abort ();                                                              \
 392      __ret; })
 393
 394
 395 /* Atomic set bit.  */
 396 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 397   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 398               asm volatile (LOCK_PREFIX "orl %1, %%gs:%P0"                    \
 399                             :: "i" (offsetof (struct pthread, member)),       \
 400                                "ir" (1 << (bit)));                            \
 401             else                                                              \
 402               /* Not necessary for other sizes in the moment.  */             \
 403               abort (); })
 404
 405
 406 /* Call the user-provided thread function.  */
 407 #define CALL_THREAD_FCT(descr) \
 408   ({ void *__res;                                                             \
 409      int __ignore1, __ignore2;                                                \
 410      asm volatile ("pushl %%eax\n\t"                                          \
 411                    "pushl %%eax\n\t"                                          \
 412                    "pushl %%eax\n\t"                                          \
 413                    "pushl %%gs:%P4\n\t"                                       \
 414                    "call *%%gs:%P3\n\t"                                       \
 415                    "addl $16, %%esp"                                          \
 416                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 417                    : "i" (offsetof (struct pthread, start_routine)),          \
 418                      "i" (offsetof (struct pthread, arg)));                   \
 419      __res; })
 420
 421
 422 /* Set the stack guard field in TCB head.  */
 423 #define THREAD_SET_STACK_GUARD(value) \
 424   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 425 #define THREAD_COPY_STACK_GUARD(descr) \
 426   ((descr)->header.stack_guard                                                \
 427    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 428
 429
 430 /* Set the pointer guard field in the TCB head.  */
 431 #define THREAD_SET_POINTER_GUARD(value) \
 432   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 433 #define THREAD_COPY_POINTER_GUARD(descr) \
 434   ((descr)->header.pointer_guard                                              \
 435    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 436
 437
 438 /* Get and set the global scope generation counter in the TCB head.  */
 439 #define THREAD_GSCOPE_FLAG_UNUSED 0
 440 #define THREAD_GSCOPE_FLAG_USED   1
 441 #define THREAD_GSCOPE_FLAG_WAIT   2
 442 #define THREAD_GSCOPE_RESET_FLAG() \
 443   do                                                                          \
 444     { int __res;                                                              \
 445       asm volatile ("xchgl %0, %%gs:%P1"                                      \
 446                     : "=r" (__res)                                            \
 447                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 448                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 449       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 450         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1);                 \
 451     }                                                                         \
 452   while (0)
 453 #define THREAD_GSCOPE_SET_FLAG() \
 454   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 455 #define THREAD_GSCOPE_WAIT() \
 456   GL(dl_wait_lookup_done) ()
 457
 458 #endif /* __ASSEMBLER__ */
 459
 460 #endif  /* tls.h */