nptl/sysdeps/unix/sysv/linux/i386/lowlevellock.h

   1 /* Copyright (C) 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   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 _LOWLEVELLOCK_H
  21 #define _LOWLEVELLOCK_H 1
  22
  23 #include <time.h>
  24 #include <sys/param.h>
  25 #include <bits/pthreadtypes.h>
  26
  27 #ifndef LOCK_INSTR
  28 # ifdef UP
  29 #  define LOCK_INSTR    /* nothing */
  30 # else
  31 #  define LOCK_INSTR "lock;"
  32 # endif
  33 #endif
  34
  35 #define SYS_futex               240
  36 #define FUTEX_WAIT              0
  37 #define FUTEX_WAKE              1
  38
  39
  40 /* Initializer for compatibility lock.  */
  41 #define LLL_MUTEX_LOCK_INITIALIZER (0)
  42
  43
  44 /* Does not preserve %eax and %ecx.  */
  45 extern int __lll_mutex_lock_wait (int val, int *__futex)
  46      __attribute ((regparm (2))) attribute_hidden;
  47 /* Does not preserver %eax, %ecx, and %edx.  */
  48 extern int __lll_mutex_timedlock_wait (int val, int *__futex,
  49                                  const struct timespec *abstime)
  50      __attribute ((regparm (3))) attribute_hidden;
  51 /* Preserves all registers but %eax.  */
  52 extern int __lll_mutex_unlock_wait (int *__futex)
  53      __attribute ((regparm (1))) attribute_hidden;
  54
  55
  56 #define lll_mutex_trylock(futex) \
  57   ({ unsigned char ret;                                                       \
  58      __asm __volatile (LOCK_INSTR "cmpxchgl %2, %1; setne %0"                 \
  59                        : "=a" (ret), "=m" (futex)                             \
  60                        : "r" (1), "1" (futex), "0" (0)                        \
  61                        : "memory");                                           \
  62      ret; })
  63
  64
  65 #define lll_mutex_lock(futex) \
  66   (void) ({ int ignore1, ignore2;                                             \
  67             __asm __volatile (LOCK_INSTR "xaddl %0, %2\n\t"                   \
  68                               "testl %0, %0\n\t"                              \
  69                               "jne 1f\n\t"                                    \
  70                               ".subsection 1\n"                               \
  71                               "1:\tleal %2, %%ecx\n\t"                        \
  72                               "call __lll_mutex_lock_wait\n\t"                \
  73                               "jmp 2f\n\t"                                    \
  74                               ".previous\n"                                   \
  75                               "2:"                                            \
  76                               : "=a" (ignore1), "=&c" (ignore2), "=m" (futex) \
  77                               : "0" (1), "2" (futex)                          \
  78                               : "memory"); })
  79
  80
  81 #define lll_mutex_timedlock(futex, timeout) \
  82   ({ int result, ignore1, ignore2;                                            \
  83      __asm __volatile (LOCK_INSTR "xaddl %0, %3\n\t"                          \
  84                        "testl %0, %0\n\t"                                     \
  85                        "jne 1f\n\t"                                           \
  86                        ".subsection 1\n"                                      \
  87                        "1:\tleal %3, %%ecx\n\t"                               \
  88                        "movl %6, %%edx\n\t"                                   \
  89                        "call __lll_mutex_timedlock_wait\n\t"                  \
  90                        "jmp 2f\n\t"                                           \
  91                        ".previous\n"                                          \
  92                        "2:"                                                   \
  93                        : "=a" (result), "=&c" (ignore1), "=&d" (ignore2),     \
  94                          "=m" (futex)                                         \
  95                        : "0" (1), "3" (futex), "m" (timeout)                  \
  96                        : "memory");                                           \
  97      result; })
  98
  99
 100 #define lll_mutex_unlock(futex) \
 101   (void) ({ int ignore;                                                       \
 102             __asm __volatile (LOCK_INSTR "decl %0\n\t"                        \
 103                               "jne 1f\n\t"                                    \
 104                               ".subsection 1\n"                               \
 105                               "1:\tleal %0, %%eax\n\t"                        \
 106                               "call __lll_mutex_unlock_wake\n\t"              \
 107                               "jmp 2f\n\t"                                    \
 108                               ".previous\n"                                   \
 109                               "2:"                                            \
 110                               : "=m" (futex), "=&a" (ignore)                  \
 111                               : "0" (futex)                                   \
 112                               : "memory"); })
 113
 114
 115 #define lll_mutex_islocked(futex) \
 116   (futex != 0)
 117
 118
 119 /* We have a separate internal lock implementation which is not tied
 120    to binary compatibility.  */
 121
 122 /* Type for lock object.  */
 123 typedef int lll_lock_t;
 124
 125 /* Initializers for lock.  */
 126 #define LLL_LOCK_INITIALIZER            (1)
 127 #define LLL_LOCK_INITIALIZER_LOCKED     (0)
 128
 129
 130 extern int __lll_lock_wait (int val, int *__futex)
 131      __attribute ((regparm (2))) attribute_hidden;
 132 extern int __lll_unlock_wake (int *__futex)
 133      __attribute ((regparm (1))) attribute_hidden;
 134 extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
 135
 136
 137 /* The states of a lock are:
 138     1  -  untaken
 139     0  -  taken by one user
 140    <0  -  taken by more users */
 141
 142
 143 #if defined NOT_IN_libc || defined UP
 144 # define lll_trylock(futex) \
 145   ({ unsigned char ret;                                                       \
 146      __asm __volatile (LOCK_INSTR "cmpxchgl %2, %1; setne %0"                 \
 147                        : "=a" (ret), "=m" (futex)                             \
 148                        : "r" (0), "1" (futex), "0" (1)                        \
 149                        : "memory");                                           \
 150      ret; })
 151
 152
 153 # define lll_lock(futex) \
 154   (void) ({ int ignore1, ignore2;                                             \
 155             __asm __volatile (LOCK_INSTR "xaddl %0, %2\n\t"                   \
 156                               "jne 1f\n\t"                                    \
 157                               ".subsection 1\n"                               \
 158                               "1:\tleal %2, %%ecx\n\t"                        \
 159                               "call __lll_lock_wait\n\t"                      \
 160                               "jmp 2f\n\t"                                    \
 161                               ".previous\n"                                   \
 162                               "2:"                                            \
 163                               : "=a" (ignore1), "=&c" (ignore2), "=m" (futex) \
 164                               : "0" (-1), "2" (futex)                         \
 165                               : "memory"); })
 166
 167
 168 # define lll_unlock(futex) \
 169   (void) ({ int ignore;                                                       \
 170             __asm __volatile (LOCK_INSTR "incl %0\n\t"                        \
 171                               "jng 1f\n\t"                                    \
 172                               ".subsection 1\n"                               \
 173                               "1:\tleal %0, %%eax\n\t"                        \
 174                               "call __lll_unlock_wake\n\t"                    \
 175                               "jmp 2f\n\t"                                    \
 176                               ".previous\n"                                   \
 177                               "2:"                                            \
 178                               : "=m" (futex), "=&a" (ignore)                  \
 179                               : "0" (futex)                                   \
 180                               : "memory"); })
 181 #else
 182 /* Special versions of the macros for use in libc itself.  They avoid
 183    the lock prefix when the thread library is not used.
 184
 185    XXX In future we might even want to avoid it on UP machines.  */
 186 # include <tls.h>
 187
 188 /* Nonzero if locking is needed.  */
 189 extern int __libc_locking_needed attribute_hidden;
 190
 191 # define lll_trylock(futex) \
 192   ({ unsigned char ret;                                                       \
 193      __asm __volatile ("cmpl $0, %%gs:%P5\n\t"                                \
 194                        "je,pt 0f\n\t"                                         \
 195                        "lock\n"                                               \
 196                        "0:\tcmpxchgl %2, %1; setne %0"                        \
 197                        : "=a" (ret), "=m" (futex)                             \
 198                        : "r" (0), "1" (futex), "0" (1),                       \
 199                          "i" (offsetof (tcbhead_t, multiple_threads))         \
 200                        : "memory");                                           \
 201      ret; })
 202
 203
 204 # define lll_lock(futex) \
 205   (void) ({ int ignore1, ignore2;                                             \
 206             __asm __volatile ("cmpl $0, %%gs:%P5\n\t"                         \
 207                               "je,pt 0f\n\t"                                  \
 208                               "lock\n"                                        \
 209                               "0:\txaddl %0, %2\n\t"                          \
 210                               "jne 1f\n\t"                                    \
 211                               ".subsection 1\n"                               \
 212                               "1:\tleal %2, %%ecx\n\t"                        \
 213                               "call __lll_lock_wait\n\t"                      \
 214                               "jmp 2f\n\t"                                    \
 215                               ".previous\n"                                   \
 216                               "2:"                                            \
 217                               : "=a" (ignore1), "=&c" (ignore2), "=m" (futex) \
 218                               : "0" (-1), "2" (futex),                        \
 219                                 "i" (offsetof (tcbhead_t, multiple_threads))  \
 220                               : "memory"); })
 221
 222
 223 # define lll_unlock(futex) \
 224   (void) ({ int ignore;                                                       \
 225             __asm __volatile ("cmpl $0, %%gs:%P3\n\t"                         \
 226                               "je,pt 0f\n\t"                                  \
 227                               "lock\n"                                        \
 228                               "0:\tincl %0\n\t"                               \
 229                               "jng 1f\n\t"                                    \
 230                               ".subsection 1\n"                               \
 231                               "1:\tleal %0, %%eax\n\t"                        \
 232                               "call __lll_unlock_wake\n\t"                    \
 233                               "jmp 2f\n\t"                                    \
 234                               ".previous\n"                                   \
 235                               "2:"                                            \
 236                               : "=m" (futex), "=&a" (ignore)                  \
 237                               : "0" (futex),                                  \
 238                                 "i" (offsetof (tcbhead_t, multiple_threads))  \
 239                               : "memory"); })
 240 #endif
 241
 242
 243 #define lll_islocked(futex) \
 244   (futex != 0)
 245
 246
 247 /* The kernel notifies a process with uses CLONE_CLEARTID via futex
 248    wakeup when the clone terminates.  The memory location contains the
 249    thread ID while the clone is running and is reset to zero
 250    afterwards.
 251
 252    The macro parameter must not have any side effect.  */
 253 #ifdef PIC
 254 # define LLL_TID_EBX_LOAD       "xchgl %2, %%ebx\n"
 255 # define LLL_TID_EBX_REG        "D"
 256 #else
 257 # define LLL_TID_EBX_LOAD
 258 # define LLL_TID_EBX_REG        "b"
 259 #endif
 260 #define lll_wait_tid(tid) \
 261   do {                                                                        \
 262     int __ignore;                                                             \
 263     register __typeof (tid) _tid asm ("edx") = (tid);                         \
 264     if (_tid != 0)                                                            \
 265       __asm __volatile (LLL_TID_EBX_LOAD                                      \
 266                         "1:\tmovl %1, %%eax\n\t"                              \
 267                         "int $0x80\n\t"                                       \
 268                         "cmpl $0, (%%ebx)\n\t"                                \
 269                         "jne,pn 1b\n\t"                                       \
 270                         LLL_TID_EBX_LOAD                                      \
 271                         : "=&a" (__ignore)                                    \
 272                         : "i" (SYS_futex), LLL_TID_EBX_REG (&tid), "S" (0),   \
 273                           "c" (FUTEX_WAIT), "d" (_tid));                      \
 274   } while (0)
 275
 276 extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime)
 277      __attribute__ ((regparm (2))) attribute_hidden;
 278 #define lll_timedwait_tid(tid, abstime) \
 279   ({                                                                          \
 280     int __result = 0;                                                         \
 281     if (tid != 0)                                                             \
 282       {                                                                       \
 283         if (abstime == NULL || abstime->tv_nsec >= 1000000000)                \
 284           __result = EINVAL;                                                  \
 285         else                                                                  \
 286           __result = __lll_timedwait_tid (&tid, abstime);                     \
 287       }                                                                       \
 288     __result; })
 289
 290
 291 #define lll_wake_tid(tid) \
 292   do {                                                                        \
 293     int __ignore;                                                             \
 294     (tid) = 0;                                                                \
 295     __asm __volatile (LLL_TID_EBX_LOAD                                        \
 296                       "\tint $0x80\n\t"                                       \
 297                       LLL_TID_EBX_LOAD                                        \
 298                       : "=a" (__ignore)                                       \
 299                       : "0" (SYS_futex), LLL_TID_EBX_REG (&(tid)), "S" (0),   \
 300                         "c" (FUTEX_WAKE), "d" (0x7fffffff));                  \
 301   } while (0)
 302
 303
 304 /* Conditional variable handling.  */
 305
 306 extern void __lll_cond_wait (pthread_cond_t *cond)
 307      __attribute ((regparm (1))) attribute_hidden;
 308 extern int __lll_cond_timedwait (pthread_cond_t *cond,
 309                                  const struct timespec *abstime)
 310      __attribute ((regparm (2))) attribute_hidden;
 311 extern void __lll_cond_wake (pthread_cond_t *cond)
 312      __attribute ((regparm (1))) attribute_hidden;
 313 extern void __lll_cond_broadcast (pthread_cond_t *cond)
 314      __attribute ((regparm (1))) attribute_hidden;
 315
 316
 317 #define lll_cond_wait(cond) \
 318   __lll_cond_wait (cond)
 319 #define lll_cond_timedwait(cond, abstime) \
 320   __lll_cond_timedwait (cond, abstime)
 321 #define lll_cond_wake(cond) \
 322   __lll_cond_wake (cond)
 323 #define lll_cond_broadcast(cond) \
 324   __lll_cond_broadcast (cond)
 325
 326
 327 #endif  /* lowlevellock.h */