sysdeps/unix/sysv/linux/hppa/nptl/lowlevellock.c

   1 /* low level locking for pthread library.  Generic futex-using version.
   2    Copyright (C) 2003, 2007 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <errno.h>
  22 #include <sysdep.h>
  23 #include <lowlevellock.h>
  24 #include <sys/time.h>
  25
  26 void
  27 __lll_lock_wait (lll_lock_t *futex, int private)
  28 {
  29   do
  30     {
  31       int oldval = atomic_compare_and_exchange_val_acq (futex, 2, 1);
  32       if (oldval != 0)
  33         lll_futex_wait (futex, 2, private);
  34     }
  35   while (atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0);
  36 }
  37
  38 void
  39 __lll_lock_wait_private (lll_lock_t *futex)
  40 {
  41   do
  42     {
  43       int oldval = atomic_compare_and_exchange_val_acq (futex, 2, 1);
  44       if (oldval != 0)
  45         lll_futex_wait (futex, 2, LLL_PRIVATE);
  46     }
  47   while (atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0);
  48 }
  49
  50 int
  51 __lll_timedlock_wait (lll_lock_t *futex, const struct timespec *abstime, int private)
  52 {
  53   /* Reject invalid timeouts.  */
  54   if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
  55     return EINVAL;
  56
  57   do
  58     {
  59       struct timeval tv;
  60       struct timespec rt;
  61
  62       /* Get the current time.  */
  63       (void) __gettimeofday (&tv, NULL);
  64
  65       /* Compute relative timeout.  */
  66       rt.tv_sec = abstime->tv_sec - tv.tv_sec;
  67       rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
  68       if (rt.tv_nsec < 0)
  69         {
  70           rt.tv_nsec += 1000000000;
  71           --rt.tv_sec;
  72         }
  73
  74       /* Already timed out?  */
  75       if (rt.tv_sec < 0)
  76         return ETIMEDOUT;
  77
  78       /* Wait.  */
  79       int oldval = atomic_compare_and_exchange_val_acq (futex, 2, 1);
  80       if (oldval != 0)
  81         lll_futex_timed_wait (futex, 2, &rt, private);
  82     }
  83   while (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0);
  84   return 0;
  85 }
  86
  87
  88 /* These don't get included in libc.so  */
  89 #ifdef IS_IN_libpthread
  90 int
  91 lll_unlock_wake_cb (lll_lock_t *futex)
  92 {
  93   int val = atomic_exchange_rel (futex, 0);
  94
  95   if (__builtin_expect (val > 1, 0))
  96     lll_private_futex_wake (futex, 1);
  97   return 0;
  98 }
  99
 100
 101 int
 102 __lll_timedwait_tid (int *tidp, const struct timespec *abstime)
 103 {
 104   int tid;
 105
 106   if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
 107     return EINVAL;
 108
 109   /* Repeat until thread terminated.  */
 110   while ((tid = *tidp) != 0)
 111     {
 112       struct timeval tv;
 113       struct timespec rt;
 114
 115       /* Get the current time.  */
 116       (void) __gettimeofday (&tv, NULL);
 117
 118       /* Compute relative timeout.  */
 119       rt.tv_sec = abstime->tv_sec - tv.tv_sec;
 120       rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
 121       if (rt.tv_nsec < 0)
 122         {
 123           rt.tv_nsec += 1000000000;
 124           --rt.tv_sec;
 125         }
 126
 127       /* Already timed out?  */
 128       if (rt.tv_sec < 0)
 129         return ETIMEDOUT;
 130
 131       /* Wait until thread terminates.  */
 132       if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
 133         return ETIMEDOUT;
 134     }
 135
 136   return 0;
 137 }
 138
 139 #endif
 140