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

   1 /* Copyright (C) 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
   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 Libr    \ary; 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 #define __NR_futex              221
  28 #define FUTEX_WAIT              0
  29 #define FUTEX_WAKE              1
  30
  31 /* Initializer for compatibility lock.  */
  32 #define LLL_MUTEX_LOCK_INITIALIZER (0)
  33
  34 #define lll_futex_wait(futexp, val) \
  35   ({                                                                          \
  36     INTERNAL_SYSCALL_DECL (__err);                                            \
  37     long int __ret;                                                           \
  38                                                                               \
  39     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  40                               (futexp), FUTEX_WAIT, (val), 0);                \
  41     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0;                       \
  42   })
  43
  44 #define lll_futex_timed_wait(futexp, val, timespec) \
  45   ({                                                                          \
  46     INTERNAL_SYSCALL_DECL (__err);                                            \
  47     long int __ret;                                                           \
  48                                                                               \
  49     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  50                               (futexp), FUTEX_WAIT, (val), (timespec));       \
  51     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0;                       \
  52   })
  53
  54 #define lll_futex_wake(futexp, nr) \
  55   ({                                                                          \
  56     INTERNAL_SYSCALL_DECL (__err);                                            \
  57     long int __ret;                                                           \
  58                                                                               \
  59     __ret = INTERNAL_SYSCALL (futex, __err, 4,                                \
  60                               (futexp), FUTEX_WAKE, (nr), 0);                 \
  61     INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0;                       \
  62   })
  63
  64 #ifdef UP
  65 # define __lll_acq_instr        ""
  66 # define __lll_rel_instr        ""
  67 #else
  68 # define __lll_acq_instr        "isync"
  69 # define __lll_rel_instr        "sync"
  70 #endif
  71
  72 /* Set *futex to 1 if it is 0, atomically.  Returns the old value */
  73 #define __lll_trylock(futex) \
  74   ({ int __val;                                                               \
  75      __asm __volatile ("1:      lwarx   %0,0,%2\n"                            \
  76                        "        cmpwi   0,%0,0\n"                             \
  77                        "        bne     2f\n"                                 \
  78                        "        stwcx.  %3,0,%2\n"                            \
  79                        "        bne-    1b\n"                                 \
  80                        "2:      " __lll_acq_instr                             \
  81                        : "=&r" (__val), "=m" (*futex)                         \
  82                        : "r" (futex), "r" (1), "1" (*futex)                   \
  83                        : "cr0", "memory");                                    \
  84      __val;                                                                   \
  85   })
  86
  87 #define lll_mutex_trylock(lock) __lll_trylock(&(lock))
  88
  89 /* Add inc to *futex atomically and return the old value. */
  90 #define __lll_add(futex, inc) \
  91   ({ int __val, __tmp;                                                        \
  92      __asm __volatile ("1:      lwarx   %0,0,%3\n"                            \
  93                        "        addi    %1,%0,%4\n"                           \
  94                        "        stwcx.  %1,0,%3\n"                            \
  95                        "        bne-    1b"                                   \
  96                        : "=&b" (__val), "=&r" (__tmp), "=m" (*futex)          \
  97                        : "r" (futex), "I" (inc), "2" (*futex)                 \
  98                        : "cr0");                                              \
  99      __val;                                                                   \
 100   })
 101
 102 extern void __lll_lock_wait (int *futex, int val) attribute_hidden;
 103
 104 #define lll_mutex_lock(lock) \
 105   (void) ({                                                                   \
 106     int *__futex = &(lock);                                                   \
 107     int __val = __lll_add (__futex, 1);                                       \
 108     __asm __volatile (__lll_acq_instr ::: "memory");                          \
 109     if (__builtin_expect (__val != 0, 0))                                     \
 110       __lll_lock_wait (__futex, __val);                                       \
 111   })
 112
 113 extern int __lll_timedlock_wait
 114         (int *futex, int val, const struct timespec *) attribute_hidden;
 115
 116 #define lll_mutex_timedlock(lock, abstime) \
 117   ({ int *__futex = &(lock);                                                  \
 118      int __val = __lll_add (__futex, 1);                                      \
 119      __asm __volatile (__lll_acq_instr ::: "memory");                         \
 120      if (__builtin_expect (__val != 0, 0))                                    \
 121        __val = __lll_timedlock_wait (__futex, __val, (abstime));              \
 122      __val;                                                                   \
 123   })
 124
 125 #define lll_mutex_unlock(lock) \
 126   (void) ({                                                                   \
 127     int *__futex = &(lock);                                                   \
 128      __asm __volatile (__lll_rel_instr ::: "memory");                         \
 129     int __val = __lll_add (__futex, -1);                                      \
 130     if (__builtin_expect (__val != 1, 0))                                     \
 131       {                                                                       \
 132         *__futex = 0;                                                         \
 133         lll_futex_wake (__futex, 1);                                          \
 134       }                                                                       \
 135   })
 136
 137 #define lll_mutex_islocked(futex) \
 138   (futex != 0)
 139
 140
 141 /* Our internal lock implementation is identical to the binary-compatible
 142    mutex implementation. */
 143
 144 /* Type for lock object.  */
 145 typedef int lll_lock_t;
 146
 147 /* Initializers for lock.  */
 148 #define LLL_LOCK_INITIALIZER            (0)
 149 #define LLL_LOCK_INITIALIZER_LOCKED     (1)
 150
 151 extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
 152
 153 /* The states of a lock are:
 154     0  -  untaken
 155     1  -  taken by one user
 156    >1  -  taken by more users */
 157
 158 #define lll_trylock(lock)       lll_mutex_trylock (lock)
 159 #define lll_lock(lock)          lll_mutex_lock (lock)
 160 #define lll_unlock(lock)        lll_mutex_unlock (lock)
 161 #define lll_islocked(lock)      lll_mutex_islocked (lock)
 162
 163 /* The kernel notifies a process which uses CLONE_CLEARTID via futex
 164    wakeup when the clone terminates.  The memory location contains the
 165    thread ID while the clone is running and is reset to zero
 166    afterwards.  */
 167 #define lll_wait_tid(tid) \
 168   do {                                                                        \
 169     __typeof (tid) __tid;                                                     \
 170     while ((__tid = (tid)) != 0)                                              \
 171       lll_futex_wait (&(tid), __tid);                                         \
 172   } while (0)
 173
 174 extern int __lll_timedwait_tid (int *, const struct timespec *)
 175      attribute_hidden;
 176
 177 #define lll_timedwait_tid(tid, abstime) \
 178   ({                                                                          \
 179     int __res = 0;                                                            \
 180     if ((tid) != 0)                                                           \
 181       __res = __lll_timedwait_tid (&(tid), (abstime));                        \
 182     __res;                                                                    \
 183   })
 184
 185
 186 /* Decrement *futex if it is > 0, and return the old value */
 187 #define __lll_dec_if_positive(futex) \
 188   ({ int __val, __tmp;                                                        \
 189      __asm __volatile ("1:      lwarx   %0,0,%3\n"                            \
 190                        "        cmpwi   0,%0,0\n"                             \
 191                        "        addi    %1,%0,-1\n"                           \
 192                        "        ble     2f\n"                                 \
 193                        "        stwcx.  %1,0,%3\n"                            \
 194                        "        bne-    1b\n"                                 \
 195                        "2:      " __lll_acq_instr                             \
 196                        : "=&b" (__val), "=&r" (__tmp), "=m" (*futex)          \
 197                        : "r" (futex), "2" (*futex)                            \
 198                        : "cr0");                                              \
 199      __val;                                                                   \
 200   })
 201
 202
 203 /* Conditional variable handling.  */
 204
 205 extern void __lll_cond_wait (pthread_cond_t *cond)
 206      attribute_hidden;
 207 extern int __lll_cond_timedwait (pthread_cond_t *cond,
 208                                  const struct timespec *abstime)
 209      attribute_hidden;
 210 extern void __lll_cond_wake (pthread_cond_t *cond)
 211      attribute_hidden;
 212 extern void __lll_cond_broadcast (pthread_cond_t *cond)
 213      attribute_hidden;
 214
 215 #define lll_cond_wait(cond) \
 216   __lll_cond_wait (cond)
 217 #define lll_cond_timedwait(cond, abstime) \
 218   __lll_cond_timedwait (cond, abstime)
 219 #define lll_cond_wake(cond) \
 220   __lll_cond_wake (cond)
 221 #define lll_cond_broadcast(cond) \
 222   __lll_cond_broadcast (cond)
 223
 224 #endif  /* lowlevellock.h */