nptl/sysdeps/i386/tls.h

   1 /* Definition for thread-local data handling.  nptl/i386 version.
   2    Copyright (C) 2002-2014 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 #include <dl-sysdep.h>
  23 #ifndef __ASSEMBLER__
  24 # include <stdbool.h>
  25 # include <stddef.h>
  26 # include <stdint.h>
  27 # include <stdlib.h>
  28 # include <sysdep.h>
  29 # include <libc-internal.h>
  30 # include <kernel-features.h>
  31
  32
  33 /* Type for the dtv.  */
  34 typedef union dtv
  35 {
  36   size_t counter;
  37   struct
  38   {
  39     void *val;
  40     bool is_static;
  41   } pointer;
  42 } dtv_t;
  43
  44
  45 typedef struct
  46 {
  47   void *tcb;            /* Pointer to the TCB.  Not necessarily the
  48                            thread descriptor used by libpthread.  */
  49   dtv_t *dtv;
  50   void *self;           /* Pointer to the thread descriptor.  */
  51   int multiple_threads;
  52   uintptr_t sysinfo;
  53   uintptr_t stack_guard;
  54   uintptr_t pointer_guard;
  55   int gscope_flag;
  56 #ifndef __ASSUME_PRIVATE_FUTEX
  57   int private_futex;
  58 #else
  59   int __glibc_reserved1;
  60 #endif
  61   /* Reservation of some values for the TM ABI.  */
  62   void *__private_tm[4];
  63   /* GCC split stack support.  */
  64   void *__private_ss;
  65 } tcbhead_t;
  66
  67 # define TLS_MULTIPLE_THREADS_IN_TCB 1
  68
  69 #else /* __ASSEMBLER__ */
  70 # include <tcb-offsets.h>
  71 #endif
  72
  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 /* Code to initially initialize the thread pointer.  This might need
 195    special attention since 'errno' is not yet available and if the
 196    operation can cause a failure 'errno' must not be touched.  */
 197 # define TLS_INIT_TP(thrdescr, secondcall) \
 198   ({ void *_thrdescr = (thrdescr);                                            \
 199      tcbhead_t *_head = _thrdescr;                                            \
 200      union user_desc_init _segdescr;                                          \
 201      int _result;                                                             \
 202                                                                               \
 203      _head->tcb = _thrdescr;                                                  \
 204      /* For now the thread descriptor is at the same address.  */             \
 205      _head->self = _thrdescr;                                                 \
 206      /* New syscall handling support.  */                                     \
 207      INIT_SYSINFO;                                                            \
 208                                                                               \
 209      /* The 'entry_number' field.  Let the kernel pick a value.  */           \
 210      if (secondcall)                                                          \
 211        _segdescr.vals[0] = TLS_GET_GS () >> 3;                                \
 212      else                                                                     \
 213        _segdescr.vals[0] = -1;                                                \
 214      /* The 'base_addr' field.  Pointer to the TCB.  */                       \
 215      _segdescr.vals[1] = (unsigned long int) _thrdescr;                       \
 216      /* The 'limit' field.  We use 4GB which is 0xfffff pages.  */            \
 217      _segdescr.vals[2] = 0xfffff;                                             \
 218      /* Collapsed value of the bitfield:                                      \
 219           .seg_32bit = 1                                                      \
 220           .contents = 0                                                       \
 221           .read_exec_only = 0                                                 \
 222           .limit_in_pages = 1                                                 \
 223           .seg_not_present = 0                                                \
 224           .useable = 1 */                                                     \
 225      _segdescr.vals[3] = 0x51;                                                \
 226                                                                               \
 227      /* Install the TLS.  */                                                  \
 228      asm volatile (TLS_LOAD_EBX                                               \
 229                    "int $0x80\n\t"                                            \
 230                    TLS_LOAD_EBX                                               \
 231                    : "=a" (_result), "=m" (_segdescr.desc.entry_number)       \
 232                    : "0" (__NR_set_thread_area),                              \
 233                      TLS_EBX_ARG (&_segdescr.desc), "m" (_segdescr.desc));    \
 234                                                                               \
 235      if (_result == 0)                                                        \
 236        /* We know the index in the GDT, now load the segment register.        \
 237           The use of the GDT is described by the value 3 in the lower         \
 238           three bits of the segment descriptor value.                         \
 239                                                                               \
 240           Note that we have to do this even if the numeric value of           \
 241           the descriptor does not change.  Loading the segment register       \
 242           causes the segment information from the GDT to be loaded            \
 243           which is necessary since we have changed it.   */                   \
 244        TLS_SET_GS (_segdescr.desc.entry_number * 8 + 3);                      \
 245                                                                               \
 246      _result == 0 ? NULL                                                      \
 247      : "set_thread_area failed when setting up thread-local storage\n"; })
 248
 249
 250 /* Return the address of the dtv for the current thread.  */
 251 # define THREAD_DTV() \
 252   ({ struct pthread *__pd;                                                    \
 253      THREAD_GETMEM (__pd, header.dtv); })
 254
 255
 256 /* Return the thread descriptor for the current thread.
 257
 258    The contained asm must *not* be marked volatile since otherwise
 259    assignments like
 260         pthread_descr self = thread_self();
 261    do not get optimized away.  */
 262 # define THREAD_SELF \
 263   ({ struct pthread *__self;                                                  \
 264      asm ("movl %%gs:%c1,%0" : "=r" (__self)                                  \
 265           : "i" (offsetof (struct pthread, header.self)));                    \
 266      __self;})
 267
 268 /* Magic for libthread_db to know how to do THREAD_SELF.  */
 269 # define DB_THREAD_SELF \
 270   REGISTER_THREAD_AREA (32, offsetof (struct user_regs_struct, xgs), 3) \
 271   REGISTER_THREAD_AREA (64, 26 * 8, 3) /* x86-64's user_regs_struct->gs */
 272
 273
 274 /* Read member of the thread descriptor directly.  */
 275 # define THREAD_GETMEM(descr, member) \
 276   ({ __typeof (descr->member) __value;                                        \
 277      if (sizeof (__value) == 1)                                               \
 278        asm volatile ("movb %%gs:%P2,%b0"                                      \
 279                      : "=q" (__value)                                         \
 280                      : "0" (0), "i" (offsetof (struct pthread, member)));     \
 281      else if (sizeof (__value) == 4)                                          \
 282        asm volatile ("movl %%gs:%P1,%0"                                       \
 283                      : "=r" (__value)                                         \
 284                      : "i" (offsetof (struct pthread, member)));              \
 285      else                                                                     \
 286        {                                                                      \
 287          if (sizeof (__value) != 8)                                           \
 288            /* There should not be any value with a size other than 1,         \
 289               4 or 8.  */                                                     \
 290            abort ();                                                          \
 291                                                                               \
 292          asm volatile ("movl %%gs:%P1,%%eax\n\t"                              \
 293                        "movl %%gs:%P2,%%edx"                                  \
 294                        : "=A" (__value)                                       \
 295                        : "i" (offsetof (struct pthread, member)),             \
 296                          "i" (offsetof (struct pthread, member) + 4));        \
 297        }                                                                      \
 298      __value; })
 299
 300
 301 /* Same as THREAD_GETMEM, but the member offset can be non-constant.  */
 302 # define THREAD_GETMEM_NC(descr, member, idx) \
 303   ({ __typeof (descr->member[0]) __value;                                     \
 304      if (sizeof (__value) == 1)                                               \
 305        asm volatile ("movb %%gs:%P2(%3),%b0"                                  \
 306                      : "=q" (__value)                                         \
 307                      : "0" (0), "i" (offsetof (struct pthread, member[0])),   \
 308                      "r" (idx));                                              \
 309      else if (sizeof (__value) == 4)                                          \
 310        asm volatile ("movl %%gs:%P1(,%2,4),%0"                                \
 311                      : "=r" (__value)                                         \
 312                      : "i" (offsetof (struct pthread, member[0])),            \
 313                        "r" (idx));                                            \
 314      else                                                                     \
 315        {                                                                      \
 316          if (sizeof (__value) != 8)                                           \
 317            /* There should not be any value with a size other than 1,         \
 318               4 or 8.  */                                                     \
 319            abort ();                                                          \
 320                                                                               \
 321          asm volatile  ("movl %%gs:%P1(,%2,8),%%eax\n\t"                      \
 322                         "movl %%gs:4+%P1(,%2,8),%%edx"                        \
 323                         : "=&A" (__value)                                     \
 324                         : "i" (offsetof (struct pthread, member[0])),         \
 325                           "r" (idx));                                         \
 326        }                                                                      \
 327      __value; })
 328
 329
 330 /* Same as THREAD_SETMEM, but the member offset can be non-constant.  */
 331 # define THREAD_SETMEM(descr, member, value) \
 332   ({ if (sizeof (descr->member) == 1)                                         \
 333        asm volatile ("movb %b0,%%gs:%P1" :                                    \
 334                      : "iq" (value),                                          \
 335                        "i" (offsetof (struct pthread, member)));              \
 336      else if (sizeof (descr->member) == 4)                                    \
 337        asm volatile ("movl %0,%%gs:%P1" :                                     \
 338                      : "ir" (value),                                          \
 339                        "i" (offsetof (struct pthread, member)));              \
 340      else                                                                     \
 341        {                                                                      \
 342          if (sizeof (descr->member) != 8)                                     \
 343            /* There should not be any value with a size other than 1,         \
 344               4 or 8.  */                                                     \
 345            abort ();                                                          \
 346                                                                               \
 347          asm volatile ("movl %%eax,%%gs:%P1\n\t"                              \
 348                        "movl %%edx,%%gs:%P2" :                                \
 349                        : "A" ((uint64_t) cast_to_integer (value)),            \
 350                          "i" (offsetof (struct pthread, member)),             \
 351                          "i" (offsetof (struct pthread, member) + 4));        \
 352        }})
 353
 354
 355 /* Set member of the thread descriptor directly.  */
 356 # define THREAD_SETMEM_NC(descr, member, idx, value) \
 357   ({ if (sizeof (descr->member[0]) == 1)                                      \
 358        asm volatile ("movb %b0,%%gs:%P1(%2)" :                                \
 359                      : "iq" (value),                                          \
 360                        "i" (offsetof (struct pthread, member)),               \
 361                        "r" (idx));                                            \
 362      else if (sizeof (descr->member[0]) == 4)                                 \
 363        asm volatile ("movl %0,%%gs:%P1(,%2,4)" :                              \
 364                      : "ir" (value),                                          \
 365                        "i" (offsetof (struct pthread, member)),               \
 366                        "r" (idx));                                            \
 367      else                                                                     \
 368        {                                                                      \
 369          if (sizeof (descr->member[0]) != 8)                                  \
 370            /* There should not be any value with a size other than 1,         \
 371               4 or 8.  */                                                     \
 372            abort ();                                                          \
 373                                                                               \
 374          asm volatile ("movl %%eax,%%gs:%P1(,%2,8)\n\t"                       \
 375                        "movl %%edx,%%gs:4+%P1(,%2,8)" :                       \
 376                        : "A" ((uint64_t) cast_to_integer (value)),            \
 377                          "i" (offsetof (struct pthread, member)),             \
 378                          "r" (idx));                                          \
 379        }})
 380
 381
 382 /* Atomic compare and exchange on TLS, returning old value.  */
 383 #define THREAD_ATOMIC_CMPXCHG_VAL(descr, member, newval, oldval) \
 384   ({ __typeof (descr->member) __ret;                                          \
 385      __typeof (oldval) __old = (oldval);                                      \
 386      if (sizeof (descr->member) == 4)                                         \
 387        asm volatile (LOCK_PREFIX "cmpxchgl %2, %%gs:%P3"                      \
 388                      : "=a" (__ret)                                           \
 389                      : "0" (__old), "r" (newval),                             \
 390                        "i" (offsetof (struct pthread, member)));              \
 391      else                                                                     \
 392        /* Not necessary for other sizes in the moment.  */                    \
 393        abort ();                                                              \
 394      __ret; })
 395
 396
 397 /* Atomic logical and.  */
 398 #define THREAD_ATOMIC_AND(descr, member, val) \
 399   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 400               asm volatile (LOCK_PREFIX "andl %1, %%gs:%P0"                   \
 401                             :: "i" (offsetof (struct pthread, member)),       \
 402                                "ir" (val));                                   \
 403             else                                                              \
 404               /* Not necessary for other sizes in the moment.  */             \
 405               abort (); })
 406
 407
 408 /* Atomic set bit.  */
 409 #define THREAD_ATOMIC_BIT_SET(descr, member, bit) \
 410   (void) ({ if (sizeof ((descr)->member) == 4)                                \
 411               asm volatile (LOCK_PREFIX "orl %1, %%gs:%P0"                    \
 412                             :: "i" (offsetof (struct pthread, member)),       \
 413                                "ir" (1 << (bit)));                            \
 414             else                                                              \
 415               /* Not necessary for other sizes in the moment.  */             \
 416               abort (); })
 417
 418
 419 /* Call the user-provided thread function.  */
 420 #define CALL_THREAD_FCT(descr) \
 421   ({ void *__res;                                                             \
 422      int __ignore1, __ignore2;                                                \
 423      asm volatile ("pushl %%eax\n\t"                                          \
 424                    "pushl %%eax\n\t"                                          \
 425                    "pushl %%eax\n\t"                                          \
 426                    "pushl %%gs:%P4\n\t"                                       \
 427                    "call *%%gs:%P3\n\t"                                       \
 428                    "addl $16, %%esp"                                          \
 429                    : "=a" (__res), "=c" (__ignore1), "=d" (__ignore2)         \
 430                    : "i" (offsetof (struct pthread, start_routine)),          \
 431                      "i" (offsetof (struct pthread, arg)));                   \
 432      __res; })
 433
 434
 435 /* Set the stack guard field in TCB head.  */
 436 #define THREAD_SET_STACK_GUARD(value) \
 437   THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
 438 #define THREAD_COPY_STACK_GUARD(descr) \
 439   ((descr)->header.stack_guard                                                \
 440    = THREAD_GETMEM (THREAD_SELF, header.stack_guard))
 441
 442
 443 /* Set the pointer guard field in the TCB head.  */
 444 #define THREAD_SET_POINTER_GUARD(value) \
 445   THREAD_SETMEM (THREAD_SELF, header.pointer_guard, value)
 446 #define THREAD_COPY_POINTER_GUARD(descr) \
 447   ((descr)->header.pointer_guard                                              \
 448    = THREAD_GETMEM (THREAD_SELF, header.pointer_guard))
 449
 450
 451 /* Get and set the global scope generation counter in the TCB head.  */
 452 #define THREAD_GSCOPE_FLAG_UNUSED 0
 453 #define THREAD_GSCOPE_FLAG_USED   1
 454 #define THREAD_GSCOPE_FLAG_WAIT   2
 455 #define THREAD_GSCOPE_RESET_FLAG() \
 456   do                                                                          \
 457     { int __res;                                                              \
 458       asm volatile ("xchgl %0, %%gs:%P1"                                      \
 459                     : "=r" (__res)                                            \
 460                     : "i" (offsetof (struct pthread, header.gscope_flag)),    \
 461                       "0" (THREAD_GSCOPE_FLAG_UNUSED));                       \
 462       if (__res == THREAD_GSCOPE_FLAG_WAIT)                                   \
 463         lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE);    \
 464     }                                                                         \
 465   while (0)
 466 #define THREAD_GSCOPE_SET_FLAG() \
 467   THREAD_SETMEM (THREAD_SELF, header.gscope_flag, THREAD_GSCOPE_FLAG_USED)
 468 #define THREAD_GSCOPE_WAIT() \
 469   GL(dl_wait_lookup_done) ()
 470
 471 #endif /* __ASSEMBLER__ */
 472
 473 #endif  /* tls.h */