nptl/sysdeps/i386/tls.h

   1 /* Definition for thread-local data handling.  nptl/i386 version.
   2    Copyright (C) 2002-2007, 2009 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 # include <sysdep.h>
  31 # include <kernel-features.h>
  32
  33
  34 /* Type for the dtv.  */
  35 typedef union dtv
  36 {
  37   size_t counter;
  38   struct
  39   {
  40     void *val;
  41     bool is_static;
  42   } pointer;
  43 } dtv_t;
  44
  45
  46 typedef struct
  47 {
  48   void *tcb;            /* Pointer to the TCB.  Not necessarily the
  49                            thread descriptor used by libpthread.  */
  50   dtv_t *dtv;
  51   void *self;           /* Pointer to the thread descriptor.  */
  52   int multiple_threads;
  53   uintptr_t sysinfo;
  54   uintptr_t stack_guard;
  55   uintptr_t pointer_guard;
  56   int gscope_flag;
  57 #ifndef __ASSUME_PRIVATE_FUTEX
  58   int private_futex;
  59 #else
  60   int __unused1;
  61 #endif
  62   /* Reservation of some values for the TM ABI.  */
  63   void *__private_tm[5];
  64 } tcbhead_t;
  65
  66 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  67
  68 #else /* __ASSEMBLER__ */
  69 # include <tcb-offsets.h>
  70 #endif
  71
  72
  73 /* We require TLS support in the tools.  */
  74 #ifndef HAVE_TLS_SUPPORT
  75 # error "TLS support is required."
  76 #endif
  77
  78 /* Alignment requirement for the stack.  For IA-32 this is governed by
  79    the SSE memory functions.  */
  80 #define STACK_ALIGN     16
  81
  82 #ifndef __ASSEMBLER__
  83 /* Get system call information.  */
  84 # include <sysdep.h>
  85
  86 /* The old way: using LDT.  */
  87
  88 /* Structure passed to `modify_ldt', 'set_thread_area', and 'clone' calls.  */
  89 struct user_desc
  90 {
  91   unsigned int entry_number;
  92   unsigned long int base_addr;
  93   unsigned int limit;
  94   unsigned int seg_32bit:1;
  95   unsigned int contents:2;
  96   unsigned int read_exec_only:1;
  97   unsigned int limit_in_pages:1;
  98   unsigned int seg_not_present:1;
  99   unsigned int useable:1;
 100   unsigned int empty:25;
 101 };
 102
 103 /* Initializing bit fields is slow.  We speed it up by using a union.  */
 104 union user_desc_init
 105 {
 106   struct user_desc desc;
 107   unsigned int vals[4];
 108 };
 109
 110
 111 /* Get the thread descriptor definition.  */
 112 # include <nptl/descr.h>
 113
 114 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
 115    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
 116    struct pthread even when not linked with -lpthread.  */
 117 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
 118
 119 /* Alignment requirements for the initial TCB.  */
 120 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 121
 122 /* This is the size of the TCB.  */
 123 # define TLS_TCB_SIZE sizeof (struct pthread)
 124
 125 /* Alignment requirements for the TCB.  */
 126 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 127
 128 /* The TCB can have any size and the memory following the address the
 129    thread pointer points to is unspecified.  Allocate the TCB there.  */
 130 # define TLS_TCB_AT_TP  1
 131
 132
 133 /* Install the dtv pointer.  The pointer passed is to the element with
 134    index -1 which contain the length.  */
 135 # define INSTALL_DTV(descr, dtvp) \
 136   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 137
 138 /* Install new dtv for current thread.  */
 139 # define INSTALL_NEW_DTV(dtvp) \
 140   ({ struct pthread *__pd;                                                    \
 141      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 142
 143 /* Return dtv of given thread descriptor.  */
 144 # define GET_DTV(descr) \
 145   (((tcbhead_t *) (descr))->dtv)
 146
 147 #define THREAD_SELF_SYSINFO     THREAD_GETMEM (THREAD_SELF, header.sysinfo)
 148 #define THREAD_SYSINFO(pd)      ((pd)->header.sysinfo)
 149
 150 /* Macros to load from and store into segment registers.  */
 151 # ifndef TLS_GET_GS
 152 #  define TLS_GET_GS() \
 153   ({ int __seg; __asm ("movw %%gs, %w0" : "=q" (__seg)); __seg & 0xffff; })
 154 # endif
 155 # ifndef TLS_SET_GS
 156 #  define TLS_SET_GS(val) \
 157   __asm ("movw %w0, %%gs" :: "q" (val))
 158 # endif
 159
 160
 161 # ifndef __NR_set_thread_area
 162 #  define __NR_set_thread_area 243
 163 # endif
 164 # ifndef TLS_FLAG_WRITABLE
 165 #  define TLS_FLAG_WRITABLE             0x00000001
 166 # endif
 167
 168 // XXX Enable for the real world.
 169 #if 0
 170 # ifndef __ASSUME_SET_THREAD_AREA
 171 #  error "we need set_thread_area"
 172 # endif
 173 #endif
 174
 175 # ifdef __PIC__
 176 #  define TLS_EBX_ARG "r"
 177 #  define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
 178 # else
 179 #  define TLS_EBX_ARG "b"
 180 #  define TLS_LOAD_EBX
 181 # endif
 182
 183 #if defined NEED_DL_SYSINFO
 184 # define INIT_SYSINFO \
 185   _head->sysinfo = GLRO(dl_sysinfo)
 186 #else
 187 # define INIT_SYSINFO
 188 #endif
 189
 190 #ifndef LOCK_PREFIX
 191 # ifdef UP
 192 #  define LOCK_PREFIX  /* nothing */
 193 # else
 194 #  define LOCK_PREFIX "lock;"
 195 # endif
 196 #endif
 197
 198 /* Code to initially initialize the thread pointer.  This might need
 199    special attention since 'errno' is not yet available and if the
 200    operation can cause a failure 'errno' must not be touched.  */
 201 # define TLS_INIT_TP(thrdescr, secondcall) \
 202   ({ void *_thrdescr = (thrdescr);                                            \
 203      tcbhead_t *_head = _thrdescr;                                            \
 204      union user_desc_init _segdescr;                                          \
 205      int _result;                                                             \
 206                                                                               \
 207      _head->tcb = _thrdescr;                                                  \
 208      /* For now the thread descriptor is at the same address.  */             \
 209      _head->self = _thrdescr;                                                 \
 210      /* New syscall handling support.  */                                     \
 211      INIT_SYSINFO;                                                            \
 212                                                                               \
 213      /* The 'entry_number' field.  Let the kernel pick a value.  */           \
 214      if (secondcall)                                                          \
 215        _segdescr.vals[0] = TLS_GET_GS () >> 3;                                \
 216      else                                                                     \
 217        _segdescr.vals[0] = -1;                                                \
 218      /* The 'base_addr' field.  Pointer to the TCB.  */                       \
 219      _segdescr.vals[1] = (unsigned long int) _thrdescr;                       \
 220      /* The 'limit' field.  We use 4GB which is 0xfffff pages.  */            \
 221      _segdescr.vals[2] = 0xfffff;                                             \
 222      /* Collapsed value of the bitfield:                                      \
 223           .seg_32bit = 1                                                      \
 224           .contents = 0                                                       \
 225           .read_exec_only = 0                                                 \
 226           .limit_in_pages = 1                                                 \
 227           .seg_not_present = 0                                                \
 228           .useable = 1 */                                                     \
 229      _segdescr.vals[3] = 0x51;                                                \
 230                                                                               \
 231      /* Install the TLS.  */                                                  \
 232      asm volatile (TLS_LOAD_EBX                                               \
 233                    "int $0x80\n\t"                                            \
 234                    TLS_LOAD_EBX                                               \
 235                    : "=a" (_result), "=m" (_segdescr.desc.entry_number)       \
 236                    : "0" (__NR_set_thread_area),                              \
 237                      TLS_EBX_ARG (&_segdescr.desc), "m" (_segdescr.desc));    \
 238                                                                               \
 239      if (_result == 0)                                                        \
 240        /* We know the index in the GDT, now load the segment register.        \
 241           The use of the GDT is described by the value 3 in the lower         \
 242           three bits of the segment descriptor value.                         \
 243                                                                               \
 244           Note that we have to do this even if the numeric value of           \
 245           the descriptor does not change.  Loading the segment register       \
 246           causes the segment information from the GDT to be loaded            \
 247           which is necessary since we have changed it.   */                   \
 248        TLS_SET_GS (_segdescr.desc.entry_number * 8 + 3);                      \
 249                                                                               \
 250      _result == 0 ? NULL                                                      \
 251      : "set_thread_area failed when setting up thread-local storage\n"; })
 252
 253
 254 /* Return the address of the dtv for the current thread.  */
 255 # define THREAD_DTV() \
 256   ({ struct pthread *__pd;                                                    \
 257      THREAD_GETMEM (__pd, header.dtv); })
 258
 259
 260 /* Return the thread descriptor for the current thread.
 261
 262    The contained asm must *not* be marked volatile since otherwise
 263    assignments like
 264         pthread_descr self = thread_self();
 265    do not get optimized away.  */
 266 # define THREAD_SELF \
 267   ({ struct pthread *__self;                                                  \
 268      asm ("movl %%gs:%c1,%0" : "=r" (__self)                                  \
 269           : "i" (offsetof (struct pthread, header.self)));                    \
 270      __self;})
 271
 272 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 273 # define DB_THREAD_SELF \
 274   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 275   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 276
 277
 278 /* Read member of the thread descriptor directly.  */
 279 # define THREAD_GETMEM(descr, member) \
 280   ({ __typeof (descr->member) __value;                                        \
 281      if (sizeof (__value) == 1)                                               \
 282        asm volatile ("movb %%gs:%P2,%b0"                                      \
 283                      : "=q" (__value)                                         \
 284                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 285      else if (sizeof (__value) == 4)                                          \
 286        asm volatile ("movl %%gs:%P1,%0"                                       \
 287                      : "=r" (__value)                                         \
 288                      : "i" (offsetof (struct pthread, member)));              \
 289      else                                                                     \
 290        {                                                                      \
 291          if (sizeof (__value) != 8)                                           \
 292            /* There should not be any value with a size other than 1,         \
 293               4 or 8.  */                                                     \
 294            abort ();                                                          \
 295                                                                               \
 296          asm volatile ("movl %%gs:%P1,%%eax\n\t"                              \
 297                        "movl %%gs:%P2,%%edx"                                  \
 298                        : "=A" (__value)                                       \
 299                        : "i" (offsetof (struct pthread, member)),             \
 300                          "i" (offsetof (struct pthread, member) + 4));        \
 301        }                                                                      \
 302      __value; })
 303
 304
 305 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 306 # define THREAD_GETMEM_NC(descr, member, idx) \
 307   ({ __typeof (descr->member[0]) __value;                                     \
 308      if (sizeof (__value) == 1)                                               \
 309        asm volatile ("movb %%gs:%P2(%3),%b0"                                  \
 310                      : "=q" (__value)                                         \
 311                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 312                      "r" (idx));                                              \
 313      else if (sizeof (__value) == 4)                                          \
 314        asm volatile ("movl %%gs:%P1(,%2,4),%0"                                \
 315                      : "=r" (__value)                                         \
 316                      : "i" (offsetof (struct pthread, member[0])),            \
 317                        "r" (idx));                                            \
 318      else                                                                     \
 319        {                                                                      \
 320          if (sizeof (__value) != 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 %%gs:%P1(,%2,8),%%eax\n\t"                      \
 326                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 327                         : "=&A" (__value)                                     \
 328                         : "i" (offsetof (struct pthread, member[0])),         \
 329                           "r" (idx));                                         \
 330        }                                                                      \
 331      __value; })
 332
 333
 334 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 335 # define THREAD_SETMEM(descr, member, value) \
 336   ({ if (sizeof (descr->member) == 1)                                         \
 337        asm volatile ("movb %b0,%%gs:%P1" :                                    \
 338                      : "iq" (value),                                          \
 339                        "i" (offsetof (struct pthread, member)));              \
 340      else if (sizeof (descr->member) == 4)                                    \
 341        asm volatile ("movl %0,%%gs:%P1" :                                     \
 342                      : "ir" (value),                                          \
 343                        "i" (offsetof (struct pthread, member)));              \
 344      else                                                                     \
 345        {                                                                      \
 346          if (sizeof (descr->member) != 8)                                     \
 347            /* There should not be any value with a size other than 1,         \
 348               4 or 8.  */                                                     \
 349            abort ();                                                          \
 350                                                                               \
 351          asm volatile ("movl %%eax,%%gs:%P1\n\t"                              \
 352                        "movl %%edx,%%gs:%P2" :                                \
 353                        : "A" (value),                                         \
 354                          "i" (offsetof (struct pthread, member)),             \
 355                          "i" (offsetof (struct pthread, member) + 4));        \
 356        }})
 357
 358
 359 /* Set member of the thread descriptor directly.  */
 360 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 361   ({ if (sizeof (descr->member[0]) == 1)                                      \
 362        asm volatile ("movb %b0,%%gs:%P1(%2)" :                                \
 363                      : "iq" (value),                                          \
 364                        "i" (offsetof (struct pthread, member)),               \
 365                        "r" (idx));                                            \
 366      else if (sizeof (descr->member[0]) == 4)                                 \
 367        asm volatile ("movl %0,%%gs:%P1(,%2,4)" :                              \
 368                      : "ir" (value),                                          \
 369                        "i" (offsetof (struct pthread, member)),               \
 370                        "r" (idx));                                            \
 371      else                                                                     \
 372        {                                                                      \
 373          if (sizeof (descr->member[0]) != 8)                                  \
 374            /* There should not be any value with a size other than 1,         \
 375               4 or 8.  */                                                     \
 376            abort ();                                                          \
 377                                                                               \
 378          asm volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                       \
 379                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 380                        : "A" (value),                                         \
 381                          "i" (offsetof (struct pthread, member)),             \
 382                          "r" (idx));                                          \
 383        }})
 384
 385
 386 /* Atomic compare and exchange on TLS, returning old value.  */
 387 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 388   ({ __typeof (descr->member) __ret;                                          \
 389      __typeof (oldval) __old = (oldval);                                      \
 390      if (sizeof (descr->member) == 4)                                         \
 391        asm volatile (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                      \
 392                      : "=a" (__ret)                                           \
 393                      : "0" (__old), "r" (newval),                             \
 394                        "i" (offsetof (struct pthread, member)));              \
 395      else                                                                     \
 396        /* Not necessary for other sizes in the moment.  */                    \
 397        abort ();                                                              \
 398      __ret; })
 399
 400
 401 /* Atomic logical and.  */
 402 #define THREAD_ATOMIC_AND(descr, member, val) \
 403   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 404               asm volatile (LOCK_PREFIX "andl %1, %%gs:%P0"                   \
 405                             :: "i" (offsetof (struct pthread, member)),       \
 406                                "ir" (val));                                   \
 407             else                                                              \
 408               /* Not necessary for other sizes in the moment.  */             \
 409               abort (); })
 410
 411
 412 /* Atomic set bit.  */
 413 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 414   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 415               asm volatile (LOCK_PREFIX "orl %1, %%gs:%P0"                    \
 416                             :: "i" (offsetof (struct pthread, member)),       \
 417                                "ir" (1 << (bit)));                            \
 418             else                                                              \
 419               /* Not necessary for other sizes in the moment.  */             \
 420               abort (); })
 421
 422
 423 /* Call the user-provided thread function.  */
 424 #define CALL_THREAD_FCT(descr) \
 425   ({ void *__res;                                                             \
 426      int __ignore1, __ignore2;                                                \
 427      asm volatile ("pushl %%eax\n\t"                                          \
 428                    "pushl %%eax\n\t"                                          \
 429                    "pushl %%eax\n\t"                                          \
 430                    "pushl %%gs:%P4\n\t"                                       \
 431                    "call *%%gs:%P3\n\t"                                       \
 432                    "addl $16, %%esp"                                          \
 433                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 434                    : "i" (offsetof (struct pthread, start_routine)),          \
 435                      "i" (offsetof (struct pthread, arg)));                   \
 436      __res; })
 437
 438
 439 /* Set the stack guard field in TCB head.  */
 440 #define THREAD_SET_STACK_GUARD(value) \
 441   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 442 #define THREAD_COPY_STACK_GUARD(descr) \
 443   ((descr)->header.stack_guard                                                \
 444    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 445
 446
 447 /* Set the pointer guard field in the TCB head.  */
 448 #define THREAD_SET_POINTER_GUARD(value) \
 449   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 450 #define THREAD_COPY_POINTER_GUARD(descr) \
 451   ((descr)->header.pointer_guard                                              \
 452    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 453
 454
 455 /* Get and set the global scope generation counter in the TCB head.  */
 456 #define THREAD_GSCOPE_FLAG_UNUSED 0
 457 #define THREAD_GSCOPE_FLAG_USED   1
 458 #define THREAD_GSCOPE_FLAG_WAIT   2
 459 #define THREAD_GSCOPE_RESET_FLAG() \
 460   do                                                                          \
 461     { int __res;                                                              \
 462       asm volatile ("xchgl %0, %%gs:%P1"                                      \
 463                     : "=r" (__res)                                            \
 464                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 465                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 466       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 467         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
 468     }                                                                         \
 469   while (0)
 470 #define THREAD_GSCOPE_SET_FLAG() \
 471   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 472 #define THREAD_GSCOPE_WAIT() \
 473   GL(dl_wait_lookup_done) ()
 474
 475 #endif /* __ASSEMBLER__ */
 476
 477 #endif  /* tls.h */