l4/pkg/uclibc/lib/contrib/uclibc/libpthread/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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _TLS_H
  20 #define _TLS_H  1
  21
  22 #ifndef __ASSEMBLER__
  23 # include <stdbool.h>
  24 # include <stddef.h>
  25 # include <stdint.h>
  26 # include <stdlib.h>
  27 # include <list.h>
  28 # include <sysdep.h>
  29 # include <bits/kernel-features.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 #ifndef __ASSUME_PRIVATE_FUTEX
  56   int private_futex;
  57 #else
  58   int __unused1;
  59 #endif
  60   /* Reservation of some values for the TM ABI.  */
  61   void *__private_tm[5];
  62 } tcbhead_t;
  63
  64 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  65
  66 #else /* __ASSEMBLER__ */
  67 # include <tcb-offsets.h>
  68 #endif
  69
  70
  71 /* We require TLS support in the tools.  */
  72 #define HAVE_TLS_SUPPORT
  73 #define HAVE___THREAD 1
  74 #define HAVE_TLS_MODEL_ATTRIBUTE 1
  75
  76 /* Signal that TLS support is available.  */
  77 #define USE_TLS        1
  78
  79
  80 /* Alignment requirement for the stack.  For IA-32 this is governed by
  81    the SSE memory functions.  */
  82 #define STACK_ALIGN     16
  83
  84 #ifndef __ASSEMBLER__
  85 /* Get system call information.  */
  86 # include <sysdep.h>
  87
  88 /* The old way: using LDT.  */
  89
  90 /* Structure passed to `modify_ldt', 'set_thread_area', and 'clone' calls.  */
  91 struct user_desc
  92 {
  93   unsigned int entry_number;
  94   unsigned long int base_addr;
  95   unsigned int limit;
  96   unsigned int seg_32bit:1;
  97   unsigned int contents:2;
  98   unsigned int read_exec_only:1;
  99   unsigned int limit_in_pages:1;
 100   unsigned int seg_not_present:1;
 101   unsigned int useable:1;
 102   unsigned int empty:25;
 103 };
 104
 105 /* Initializing bit fields is slow.  We speed it up by using a union.  */
 106 union user_desc_init
 107 {
 108   struct user_desc desc;
 109   unsigned int vals[4];
 110 };
 111
 112
 113 /* Get the thread descriptor definition.  */
 114 # include <descr.h>
 115
 116 /* This is the size of the initial TCB.  Can't be just sizeof (tcbhead_t),
 117    because NPTL getpid, __libc_alloca_cutoff etc. need (almost) the whole
 118    struct pthread even when not linked with -lpthread.  */
 119 # define TLS_INIT_TCB_SIZE sizeof (struct pthread)
 120
 121 /* Alignment requirements for the initial TCB.  */
 122 # define TLS_INIT_TCB_ALIGN __alignof__ (struct pthread)
 123
 124 /* This is the size of the TCB.  */
 125 # define TLS_TCB_SIZE sizeof (struct pthread)
 126
 127 /* Alignment requirements for the TCB.  */
 128 # define TLS_TCB_ALIGN __alignof__ (struct pthread)
 129
 130 /* The TCB can have any size and the memory following the address the
 131    thread pointer points to is unspecified.  Allocate the TCB there.  */
 132 # define TLS_TCB_AT_TP  1
 133
 134
 135 /* Install the dtv pointer.  The pointer passed is to the element with
 136    index -1 which contain the length.  */
 137 # define INSTALL_DTV(descr, dtvp) \
 138   ((tcbhead_t *) (descr))->dtv = (dtvp) + 1
 139
 140 /* Install new dtv for current thread.  */
 141 # define INSTALL_NEW_DTV(dtvp) \
 142   ({ struct pthread *__pd;                                                    \
 143      THREAD_SETMEM (__pd, header.dtv, (dtvp)); })
 144
 145 /* Return dtv of given thread descriptor.  */
 146 # define GET_DTV(descr) \
 147   (((tcbhead_t *) (descr))->dtv)
 148
 149 #define THREAD_SELF_SYSINFO     THREAD_GETMEM (THREAD_SELF, header.sysinfo)
 150 #define THREAD_SYSINFO(pd)      ((pd)->header.sysinfo)
 151
 152 /* Macros to load from and store into segment registers.  */
 153 # ifndef TLS_GET_GS
 154 #  define TLS_GET_GS() \
 155   ({ int __seg; __asm__ ("movw %%gs, %w0" : "=q" (__seg)); __seg & 0xffff; })
 156 # endif
 157 # ifndef TLS_SET_GS
 158 #  define TLS_SET_GS(val) \
 159   __asm__ ("movw %w0, %%gs" :: "q" (val))
 160 # endif
 161
 162
 163 # ifndef __NR_set_thread_area
 164 #  define __NR_set_thread_area 243
 165 # endif
 166 # ifndef TLS_FLAG_WRITABLE
 167 #  define TLS_FLAG_WRITABLE             0x00000001
 168 # endif
 169
 170 // XXX Enable for the real world.
 171 #if 0
 172 # ifndef __ASSUME_SET_THREAD_AREA
 173 #  error "we need set_thread_area"
 174 # endif
 175 #endif
 176
 177 # ifdef __PIC__
 178 #  define TLS_EBX_ARG "r"
 179 #  define TLS_LOAD_EBX "xchgl %3, %%ebx\n\t"
 180 # else
 181 #  define TLS_EBX_ARG "b"
 182 #  define TLS_LOAD_EBX
 183 # endif
 184
 185 #if defined NEED_DL_SYSINFO
 186 # define INIT_SYSINFO \
 187   _head->sysinfo = GLRO(dl_sysinfo)
 188 #else
 189 # define INIT_SYSINFO
 190 #endif
 191
 192 #ifndef LOCK_PREFIX
 193 # ifdef UP
 194 #  define LOCK_PREFIX  /* nothing */
 195 # else
 196 #  define LOCK_PREFIX "lock;"
 197 # endif
 198 #endif
 199
 200 /* Code to initially initialize the thread pointer.  This might need
 201    special attention since 'errno' is not yet available and if the
 202    operation can cause a failure 'errno' must not be touched.  */
 203 # define TLS_INIT_TP(thrdescr, secondcall) \
 204   ({ void *_thrdescr = (thrdescr);                                            \
 205      tcbhead_t *_head = _thrdescr;                                            \
 206      union user_desc_init _segdescr;                                          \
 207      int _result;                                                             \
 208                                                                               \
 209      _head->tcb = _thrdescr;                                                  \
 210      /* For now the thread descriptor is at the same address.  */             \
 211      _head->self = _thrdescr;                                                 \
 212      /* New syscall handling support.  */                                     \
 213      INIT_SYSINFO;                                                            \
 214                                                                               \
 215      /* The 'entry_number' field.  Let the kernel pick a value.  */           \
 216      if (secondcall)                                                          \
 217        _segdescr.vals[0] = TLS_GET_GS () >> 3;                                \
 218      else                                                                     \
 219        _segdescr.vals[0] = -1;                                                \
 220      /* The 'base_addr' field.  Pointer to the TCB.  */                       \
 221      _segdescr.vals[1] = (unsigned long int) _thrdescr;                       \
 222      /* The 'limit' field.  We use 4GB which is 0xfffff pages.  */            \
 223      _segdescr.vals[2] = 0xfffff;                                             \
 224      /* Collapsed value of the bitfield:                                      \
 225           .seg_32bit = 1                                                      \
 226           .contents = 0                                                       \
 227           .read_exec_only = 0                                                 \
 228           .limit_in_pages = 1                                                 \
 229           .seg_not_present = 0                                                \
 230           .useable = 1 */                                                     \
 231      _segdescr.vals[3] = 0x51;                                                \
 232                                                                               \
 233      /* Install the TLS.  */                                                  \
 234      __asm__ __volatile__ (TLS_LOAD_EBX                                           \
 235                    "int $0x80\n\t"                                            \
 236                    TLS_LOAD_EBX                                               \
 237                    : "=a" (_result), "=m" (_segdescr.desc.entry_number)       \
 238                    : "0" (__NR_set_thread_area),                              \
 239                      TLS_EBX_ARG (&_segdescr.desc), "m" (_segdescr.desc));    \
 240                                                                               \
 241      if (_result == 0)                                                        \
 242        /* We know the index in the GDT, now load the segment register.        \
 243           The use of the GDT is described by the value 3 in the lower         \
 244           three bits of the segment descriptor value.                         \
 245                                                                               \
 246           Note that we have to do this even if the numeric value of           \
 247           the descriptor does not change.  Loading the segment register       \
 248           causes the segment information from the GDT to be loaded            \
 249           which is necessary since we have changed it.   */                   \
 250        TLS_SET_GS (_segdescr.desc.entry_number * 8 + 3);                      \
 251                                                                               \
 252      _result == 0 ? NULL                                                      \
 253      : "set_thread_area failed when setting up thread-local storage\n"; })
 254
 255
 256 /* Return the address of the dtv for the current thread.  */
 257 # define THREAD_DTV() \
 258   ({ struct pthread *__pd;                                                    \
 259      THREAD_GETMEM (__pd, header.dtv); })
 260
 261
 262 /* Return the thread descriptor for the current thread.
 263
 264    The contained asm must *not* be marked __volatile__ since otherwise
 265    assignments like
 266         pthread_descr self = thread_self();
 267    do not get optimized away.  */
 268 # define THREAD_SELF \
 269   ({ struct pthread *__self;                                                  \
 270      __asm__ ("movl %%gs:%c1,%0" : "=r" (__self)                                    \
 271           : "i" (offsetof (struct pthread, header.self)));                    \
 272      __self;})
 273
 274 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 275 # define DB_THREAD_SELF \
 276   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 277   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 278
 279
 280 /* Read member of the thread descriptor directly.  */
 281 # define THREAD_GETMEM(descr, member) \
 282   ({ __typeof (descr->member) __value;                                        \
 283      if (sizeof (__value) == 1)                                               \
 284        __asm__ __volatile__ ("movb %%gs:%P2,%b0"                                    \
 285                      : "=q" (__value)                                         \
 286                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 287      else if (sizeof (__value) == 4)                                          \
 288        __asm__ __volatile__ ("movl %%gs:%P1,%0"                                     \
 289                      : "=r" (__value)                                         \
 290                      : "i" (offsetof (struct pthread, member)));              \
 291      else                                                                     \
 292        {                                                                      \
 293          if (sizeof (__value) != 8)                                           \
 294            /* There should not be any value with a size other than 1,         \
 295               4 or 8.  */                                                     \
 296            abort ();                                                          \
 297                                                                               \
 298          __asm__ __volatile__ ("movl %%gs:%P1,%%eax\n\t"                              \
 299                        "movl %%gs:%P2,%%edx"                                  \
 300                        : "=A" (__value)                                       \
 301                        : "i" (offsetof (struct pthread, member)),             \
 302                          "i" (offsetof (struct pthread, member) + 4));        \
 303        }                                                                      \
 304      __value; })
 305
 306
 307 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 308 # define THREAD_GETMEM_NC(descr, member, idx) \
 309   ({ __typeof (descr->member[0]) __value;                                     \
 310      if (sizeof (__value) == 1)                                               \
 311        __asm__ __volatile__ ("movb %%gs:%P2(%3),%b0"                                  \
 312                      : "=q" (__value)                                         \
 313                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 314                      "r" (idx));                                              \
 315      else if (sizeof (__value) == 4)                                          \
 316        __asm__ __volatile__ ("movl %%gs:%P1(,%2,4),%0"                                \
 317                      : "=r" (__value)                                         \
 318                      : "i" (offsetof (struct pthread, member[0])),            \
 319                        "r" (idx));                                            \
 320      else                                                                     \
 321        {                                                                      \
 322          if (sizeof (__value) != 8)                                           \
 323            /* There should not be any value with a size other than 1,         \
 324               4 or 8.  */                                                     \
 325            abort ();                                                          \
 326                                                                               \
 327          __asm__ __volatile__  ("movl %%gs:%P1(,%2,8),%%eax\n\t"                      \
 328                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 329                         : "=&A" (__value)                                     \
 330                         : "i" (offsetof (struct pthread, member[0])),         \
 331                           "r" (idx));                                         \
 332        }                                                                      \
 333      __value; })
 334
 335
 336 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 337 # define THREAD_SETMEM(descr, member, value) \
 338   ({ if (sizeof (descr->member) == 1)                                         \
 339        __asm__ __volatile__ ("movb %b0,%%gs:%P1" :                                    \
 340                      : "iq" (value),                                          \
 341                        "i" (offsetof (struct pthread, member)));              \
 342      else if (sizeof (descr->member) == 4)                                    \
 343        __asm__ __volatile__ ("movl %0,%%gs:%P1" :                                     \
 344                      : "ir" (value),                                          \
 345                        "i" (offsetof (struct pthread, member)));              \
 346      else                                                                     \
 347        {                                                                      \
 348          if (sizeof (descr->member) != 8)                                     \
 349            /* There should not be any value with a size other than 1,         \
 350               4 or 8.  */                                                     \
 351            abort ();                                                          \
 352                                                                               \
 353          __asm__ __volatile__ ("movl %%eax,%%gs:%P1\n\t"                              \
 354                        "movl %%edx,%%gs:%P2" :                                \
 355                        : "A" (value),                                         \
 356                          "i" (offsetof (struct pthread, member)),             \
 357                          "i" (offsetof (struct pthread, member) + 4));        \
 358        }})
 359
 360
 361 /* Set member of the thread descriptor directly.  */
 362 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 363   ({ if (sizeof (descr->member[0]) == 1)                                      \
 364        __asm__ __volatile__ ("movb %b0,%%gs:%P1(%2)" :                                \
 365                      : "iq" (value),                                          \
 366                        "i" (offsetof (struct pthread, member)),               \
 367                        "r" (idx));                                            \
 368      else if (sizeof (descr->member[0]) == 4)                                 \
 369        __asm__ __volatile__ ("movl %0,%%gs:%P1(,%2,4)" :                              \
 370                      : "ir" (value),                                          \
 371                        "i" (offsetof (struct pthread, member)),               \
 372                        "r" (idx));                                            \
 373      else                                                                     \
 374        {                                                                      \
 375          if (sizeof (descr->member[0]) != 8)                                  \
 376            /* There should not be any value with a size other than 1,         \
 377               4 or 8.  */                                                     \
 378            abort ();                                                          \
 379                                                                               \
 380          __asm__ __volatile__ ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                       \
 381                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 382                        : "A" (value),                                         \
 383                          "i" (offsetof (struct pthread, member)),             \
 384                          "r" (idx));                                          \
 385        }})
 386
 387
 388 /* Atomic compare and exchange on TLS, returning old value.  */
 389 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 390   ({ __typeof (descr->member) __ret;                                          \
 391      __typeof (oldval) __old = (oldval);                                      \
 392      if (sizeof (descr->member) == 4)                                         \
 393        __asm__ __volatile__ (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                      \
 394                      : "=a" (__ret)                                           \
 395                      : "0" (__old), "r" (newval),                             \
 396                        "i" (offsetof (struct pthread, member)));              \
 397      else                                                                     \
 398        /* Not necessary for other sizes in the moment.  */                    \
 399        abort ();                                                              \
 400      __ret; })
 401
 402
 403 /* Atomic logical and.  */
 404 #define THREAD_ATOMIC_AND(descr, member, val) \
 405   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 406               __asm__ __volatile__ (LOCK_PREFIX "andl %1, %%gs:%P0"                   \
 407                             :: "i" (offsetof (struct pthread, member)),       \
 408                                "ir" (val));                                   \
 409             else                                                              \
 410               /* Not necessary for other sizes in the moment.  */             \
 411               abort (); })
 412
 413
 414 /* Atomic set bit.  */
 415 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 416   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 417               __asm__ __volatile__ (LOCK_PREFIX "orl %1, %%gs:%P0"                    \
 418                             :: "i" (offsetof (struct pthread, member)),       \
 419                                "ir" (1 << (bit)));                            \
 420             else                                                              \
 421               /* Not necessary for other sizes in the moment.  */             \
 422               abort (); })
 423
 424
 425 /* Call the user-provided thread function.  */
 426 #define CALL_THREAD_FCT(descr) \
 427   ({ void *__res;                                                             \
 428      int __ignore1, __ignore2;                                                \
 429      __asm__ __volatile__ ("pushl %%eax\n\t"                                          \
 430                    "pushl %%eax\n\t"                                          \
 431                    "pushl %%eax\n\t"                                          \
 432                    "pushl %%gs:%P4\n\t"                                       \
 433                    "call *%%gs:%P3\n\t"                                       \
 434                    "addl $16, %%esp"                                          \
 435                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 436                    : "i" (offsetof (struct pthread, start_routine)),          \
 437                      "i" (offsetof (struct pthread, arg)));                   \
 438      __res; })
 439
 440
 441 /* Set the stack guard field in TCB head.  */
 442 #define THREAD_SET_STACK_GUARD(value) \
 443   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 444 #define THREAD_COPY_STACK_GUARD(descr) \
 445   ((descr)->header.stack_guard                                                \
 446    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 447
 448
 449 /* Set the pointer guard field in the TCB head.  */
 450 #define THREAD_SET_POINTER_GUARD(value) \
 451   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 452 #define THREAD_COPY_POINTER_GUARD(descr) \
 453   ((descr)->header.pointer_guard                                              \
 454    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 455
 456
 457 /* Get and set the global scope generation counter in the TCB head.  */
 458 #define THREAD_GSCOPE_FLAG_UNUSED 0
 459 #define THREAD_GSCOPE_FLAG_USED   1
 460 #define THREAD_GSCOPE_FLAG_WAIT   2
 461 #define THREAD_GSCOPE_RESET_FLAG() \
 462   do                                                                          \
 463     { int __res;                                                              \
 464       __asm__ __volatile__ ("xchgl %0, %%gs:%P1"                                      \
 465                     : "=r" (__res)                                            \
 466                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 467                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 468       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 469         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
 470     }                                                                         \
 471   while (0)
 472 #define THREAD_GSCOPE_SET_FLAG() \
 473   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 474 #define THREAD_GSCOPE_WAIT() \
 475   GL(dl_wait_lookup_done) ()
 476
 477 #endif /* __ASSEMBLER__ */
 478
 479 #endif  /* tls.h */