nptl/sysdeps/i386/tls.h

   1 /* Definition for thread-local data handling.  nptl/i386 version.
   2    Copyright (C) 2002,2003,2004,2005,2006,2007 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 # 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 #endif
  60 } tcbhead_t;
  61
  62 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  63
  64 #else /* __ASSEMBLER__ */
  65 # include <tcb-offsets.h>
  66 #endif
  67
  68
  69 /* We require TLS support in the tools.  */
  70 #ifndef HAVE_TLS_SUPPORT
  71 # error "TLS support is required."
  72 #endif
  73
  74 /* Alignment requirement for the stack.  For IA-32 this is governed by
  75    the SSE memory functions.  */
  76 #define STACK_ALIGN     16
  77
  78 #ifndef __ASSEMBLER__
  79 /* Get system call information.  */
  80 # include <sysdep.h>
  81
  82 /* The old way: using LDT.  */
  83
  84 /* Structure passed to `modify_ldt', 'set_thread_area', and 'clone' calls.  */
  85 struct user_desc
  86 {
  87   unsigned int entry_number;
  88   unsigned long int base_addr;
  89   unsigned int limit;
  90   unsigned int seg_32bit:1;
  91   unsigned int contents:2;
  92   unsigned int read_exec_only:1;
  93   unsigned int limit_in_pages:1;
  94   unsigned int seg_not_present:1;
  95   unsigned int useable:1;
  96   unsigned int empty:25;
  97 };
  98
  99 /* Initializing bit fields is slow.  We speed it up by using a union.  */
 100 union user_desc_init
 101 {
 102   struct user_desc desc;
 103   unsigned int vals[4];
 104 };
 105
 106
 107 /* Get the thread descriptor definition.  */
 108 # include <nptl/descr.h>
 109
 110 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
 111    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
 112    struct pthread even when not linked with -lpthread.  */
 113 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
 114
 115 /* Alignment requirements for the initial TCB.  */
 116 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 117
 118 /* This is the size of the TCB.  */
 119 # define TLS_TCB_SIZE sizeof (struct pthread)
 120
 121 /* Alignment requirements for the TCB.  */
 122 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 123
 124 /* The TCB can have any size and the memory following the address the
 125    thread pointer points to is unspecified.  Allocate the TCB there.  */
 126 # define TLS_TCB_AT_TP  1
 127
 128
 129 /* Install the dtv pointer.  The pointer passed is to the element with
 130    index -1 which contain the length.  */
 131 # define INSTALL_DTV(descr, dtvp) \
 132   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 133
 134 /* Install new dtv for current thread.  */
 135 # define INSTALL_NEW_DTV(dtvp) \
 136   ({ struct pthread *__pd;                                                    \
 137      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 138
 139 /* Return dtv of given thread descriptor.  */
 140 # define GET_DTV(descr) \
 141   (((tcbhead_t *) (descr))->dtv)
 142
 143 #define THREAD_SELF_SYSINFO     THREAD_GETMEM (THREAD_SELF, header.sysinfo)
 144 #define THREAD_SYSINFO(pd)      ((pd)->header.sysinfo)
 145
 146 /* Macros to load from and store into segment registers.  */
 147 # ifndef TLS_GET_GS
 148 #  define TLS_GET_GS() \
 149   ({ int __seg; __asm ("movw %%gs, %w0" : "=q" (__seg)); __seg & 0xffff; })
 150 # endif
 151 # ifndef TLS_SET_GS
 152 #  define TLS_SET_GS(val) \
 153   __asm ("movw %w0, %%gs" :: "q" (val))
 154 # endif
 155
 156
 157 # ifndef __NR_set_thread_area
 158 #  define __NR_set_thread_area 243
 159 # endif
 160 # ifndef TLS_FLAG_WRITABLE
 161 #  define TLS_FLAG_WRITABLE             0x00000001
 162 # endif
 163
 164 // XXX Enable for the real world.
 165 #if 0
 166 # ifndef __ASSUME_SET_THREAD_AREA
 167 #  error "we need set_thread_area"
 168 # endif
 169 #endif
 170
 171 # ifdef __PIC__
 172 #  define TLS_EBX_ARG "r"
 173 #  define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
 174 # else
 175 #  define TLS_EBX_ARG "b"
 176 #  define TLS_LOAD_EBX
 177 # endif
 178
 179 #if defined NEED_DL_SYSINFO
 180 # define INIT_SYSINFO \
 181   _head->sysinfo = GLRO(dl_sysinfo)
 182 #else
 183 # define INIT_SYSINFO
 184 #endif
 185
 186 #ifndef LOCK_PREFIX
 187 # ifdef UP
 188 #  define LOCK_PREFIX  /* nothing */
 189 # else
 190 #  define LOCK_PREFIX "lock;"
 191 # endif
 192 #endif
 193
 194 #include <nacl_syscalls.h>
 195
 196 /* Code to initially initialize the thread pointer.  This might need
 197    special attention since 'errno' is not yet available and if the
 198    operation can cause a failure 'errno' must not be touched.  */
 199 # define TLS_INIT_TP(thrdescr, secondcall) \
 200   ({ void *_thrdescr = (thrdescr);                                            \
 201      tcbhead_t *_head = _thrdescr;                                            \
 202      int _result;                                                             \
 203                                                                               \
 204      _head->tcb = _thrdescr;                                                  \
 205      /* For now the thread descriptor is at the same address.  */             \
 206      _head->self = _thrdescr;                                                 \
 207      /* New syscall handling support.  */                                     \
 208      INIT_SYSINFO;                                                            \
 209      static int (*nacl_tls_init)(void const *buf, size_t size) =              \
 210        NACL_SYSCALL_ADDR(NACL_sys_tls_init);                                  \
 211      _result = nacl_tls_init (_thrdescr, 0x1000);                             \
 212      _result == 0 ? NULL                                                      \
 213      : "tls_init failed when setting up thread-local storage\n"; })
 214
 215
 216 /* Return the address of the dtv for the current thread.  */
 217 # define THREAD_DTV() \
 218   ({ struct pthread *__pd;                                                    \
 219      THREAD_GETMEM (__pd, header.dtv); })
 220
 221
 222 /* Return the thread descriptor for the current thread.
 223
 224    The contained asm must *not* be marked volatile since otherwise
 225    assignments like
 226         pthread_descr self = thread_self();
 227    do not get optimized away.  */
 228 # define THREAD_SELF \
 229   ({ struct pthread *__self;                                                  \
 230      asm ("movl %%gs:%c1,%0" : "=r" (__self)                                  \
 231           : "i" (offsetof (struct pthread, header.self)));                    \
 232      __self;})
 233
 234 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 235 # define DB_THREAD_SELF \
 236   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 237   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 238
 239
 240 /* Read member of the thread descriptor directly.  */
 241 # define THREAD_GETMEM(descr, member) \
 242   ({ __typeof (descr->member) __value;                                        \
 243      if (sizeof (__value) == 1)                                               \
 244        asm volatile ("movb %%gs:%P2,%b0"                                      \
 245                      : "=q" (__value)                                         \
 246                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 247      else if (sizeof (__value) == 4)                                          \
 248        asm volatile ("movl %%gs:%P1,%0"                                       \
 249                      : "=r" (__value)                                         \
 250                      : "i" (offsetof (struct pthread, member)));              \
 251      else                                                                     \
 252        {                                                                      \
 253          if (sizeof (__value) != 8)                                           \
 254            /* There should not be any value with a size other than 1,         \
 255               4 or 8.  */                                                     \
 256            abort ();                                                          \
 257                                                                               \
 258          asm volatile ("movl %%gs:%P1,%%eax\n\t"                              \
 259                        "movl %%gs:%P2,%%edx"                                  \
 260                        : "=A" (__value)                                       \
 261                        : "i" (offsetof (struct pthread, member)),             \
 262                          "i" (offsetof (struct pthread, member) + 4));        \
 263        }                                                                      \
 264      __value; })
 265
 266
 267 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 268 # define THREAD_GETMEM_NC(descr, member, idx) \
 269   ({ __typeof (descr->member[0]) __value;                                     \
 270      if (sizeof (__value) == 1)                                               \
 271        asm volatile ("movb %%gs:%P2(%3),%b0"                                  \
 272                      : "=q" (__value)                                         \
 273                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 274                      "r" (idx));                                              \
 275      else if (sizeof (__value) == 4)                                          \
 276        asm volatile ("movl %%gs:%P1(,%2,4),%0"                                \
 277                      : "=r" (__value)                                         \
 278                      : "i" (offsetof (struct pthread, member[0])),            \
 279                        "r" (idx));                                            \
 280      else                                                                     \
 281        {                                                                      \
 282          if (sizeof (__value) != 8)                                           \
 283            /* There should not be any value with a size other than 1,         \
 284               4 or 8.  */                                                     \
 285            abort ();                                                          \
 286                                                                               \
 287          asm volatile  ("movl %%gs:%P1(,%2,8),%%eax\n\t"                      \
 288                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 289                         : "=&A" (__value)                                     \
 290                         : "i" (offsetof (struct pthread, member[0])),         \
 291                           "r" (idx));                                         \
 292        }                                                                      \
 293      __value; })
 294
 295
 296 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 297 # define THREAD_SETMEM(descr, member, value) \
 298   ({ if (sizeof (descr->member) == 1)                                         \
 299        asm volatile ("movb %b0,%%gs:%P1" :                                    \
 300                      : "iq" (value),                                          \
 301                        "i" (offsetof (struct pthread, member)));              \
 302      else if (sizeof (descr->member) == 4)                                    \
 303        asm volatile ("movl %0,%%gs:%P1" :                                     \
 304                      : "ir" (value),                                          \
 305                        "i" (offsetof (struct pthread, member)));              \
 306      else                                                                     \
 307        {                                                                      \
 308          if (sizeof (descr->member) != 8)                                     \
 309            /* There should not be any value with a size other than 1,         \
 310               4 or 8.  */                                                     \
 311            abort ();                                                          \
 312                                                                               \
 313          asm volatile ("movl %%eax,%%gs:%P1\n\t"                              \
 314                        "movl %%edx,%%gs:%P2" :                                \
 315                        : "A" (value),                                         \
 316                          "i" (offsetof (struct pthread, member)),             \
 317                          "i" (offsetof (struct pthread, member) + 4));        \
 318        }})
 319
 320
 321 /* Set member of the thread descriptor directly.  */
 322 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 323   ({ if (sizeof (descr->member[0]) == 1)                                      \
 324        asm volatile ("movb %b0,%%gs:%P1(%2)" :                                \
 325                      : "iq" (value),                                          \
 326                        "i" (offsetof (struct pthread, member)),               \
 327                        "r" (idx));                                            \
 328      else if (sizeof (descr->member[0]) == 4)                                 \
 329        asm volatile ("movl %0,%%gs:%P1(,%2,4)" :                              \
 330                      : "ir" (value),                                          \
 331                        "i" (offsetof (struct pthread, member)),               \
 332                        "r" (idx));                                            \
 333      else                                                                     \
 334        {                                                                      \
 335          if (sizeof (descr->member[0]) != 8)                                  \
 336            /* There should not be any value with a size other than 1,         \
 337               4 or 8.  */                                                     \
 338            abort ();                                                          \
 339                                                                               \
 340          asm volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                       \
 341                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 342                        : "A" (value),                                         \
 343                          "i" (offsetof (struct pthread, member)),             \
 344                          "r" (idx));                                          \
 345        }})
 346
 347
 348 /* Atomic compare and exchange on TLS, returning old value.  */
 349 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 350   ({ __typeof (descr->member) __ret;                                          \
 351      __typeof (oldval) __old = (oldval);                                      \
 352      if (sizeof (descr->member) == 4)                                         \
 353        asm volatile (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                      \
 354                      : "=a" (__ret)                                           \
 355                      : "0" (__old), "r" (newval),                             \
 356                        "i" (offsetof (struct pthread, member)));              \
 357      else                                                                     \
 358        /* Not necessary for other sizes in the moment.  */                    \
 359        abort ();                                                              \
 360      __ret; })
 361
 362
 363 /* Atomic set bit.  */
 364 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 365   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 366               asm volatile (LOCK_PREFIX "orl %1, %%gs:%P0"                    \
 367                             :: "i" (offsetof (struct pthread, member)),       \
 368                                "ir" (1 << (bit)));                            \
 369             else                                                              \
 370               /* Not necessary for other sizes in the moment.  */             \
 371               abort (); })
 372
 373
 374 /* Call the user-provided thread function.  */
 375 #define CALL_THREAD_FCT(descr) \
 376   ({ void *__res;                                                             \
 377      int __ignore1, __ignore2;                                                \
 378      asm volatile ("pushl %%eax\n\t"                                          \
 379                    "pushl %%eax\n\t"                                          \
 380                    "pushl %%eax\n\t"                                          \
 381                    "pushl %%gs:%P4\n\t"                                       \
 382                    "call *%%gs:%P3\n\t"                                       \
 383                    "addl $16, %%esp"                                          \
 384                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 385                    : "i" (offsetof (struct pthread, start_routine)),          \
 386                      "i" (offsetof (struct pthread, arg)));                   \
 387      __res; })
 388
 389
 390 /* Set the stack guard field in TCB head.  */
 391 #define THREAD_SET_STACK_GUARD(value) \
 392   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 393 #define THREAD_COPY_STACK_GUARD(descr) \
 394   ((descr)->header.stack_guard                                                \
 395    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 396
 397
 398 /* Set the pointer guard field in the TCB head.  */
 399 #define THREAD_SET_POINTER_GUARD(value) \
 400   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 401 #define THREAD_COPY_POINTER_GUARD(descr) \
 402   ((descr)->header.pointer_guard                                              \
 403    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 404
 405
 406 /* Get and set the global scope generation counter in the TCB head.  */
 407 #define THREAD_GSCOPE_FLAG_UNUSED 0
 408 #define THREAD_GSCOPE_FLAG_USED   1
 409 #define THREAD_GSCOPE_FLAG_WAIT   2
 410 #define THREAD_GSCOPE_RESET_FLAG() \
 411   do                                                                          \
 412     { int __res;                                                              \
 413       asm volatile ("xchgl %0, %%gs:%P1"                                      \
 414                     : "=r" (__res)                                            \
 415                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 416                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 417       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 418         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
 419     }                                                                         \
 420   while (0)
 421 #define THREAD_GSCOPE_SET_FLAG() \
 422   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 423 #define THREAD_GSCOPE_WAIT() \
 424   GL(dl_wait_lookup_done) ()
 425
 426 #endif /* __ASSEMBLER__ */
 427
 428 #endif  /* tls.h */