nptl/sysdeps/i386/tls.h

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