nptl/sysdeps/i386/tls.h

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