nptl: Replace non cancellable pause/nanosleep with futex

To help y2038 work avoid duplicate all the logic of nanosleep on
non cancellable version, the patch replace it with a new futex
operation, lll_timedwait.  The changes are:

  - Add a expected value for __lll_clocklock_wait, so it can be used
    to wait for generic values.

  - Remove its internal atomic operation and move the logic to
    __lll_clocklock.  It makes __lll_clocklock_wait even more generic
    and __lll_clocklock slight faster on fast-path (since it won't
    require a function call anymore).

  - Add lll_timedwait, which uses __lll_clocklock_wait, to replace both
    __pause_nocancel and __nanosleep_nocancel.

It also allows remove the sparc32 __lll_clocklock_wait implementation
(since it is similar to the generic one).

Checked on x86_64-linux-gnu, sparcv9-linux-gnu, and i686-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 4 insertions, 16 deletions

diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
index d6f0d9e31a..76b93bddc6 100644
--- a/nptl/pthread_mutex_timedlock.c
+++ b/nptl/pthread_mutex_timedlock.c
@@ -401,22 +401,10 @@ __pthread_mutex_clocklock_common (pthread_mutex_t *mutex,
 
 		    /* Delay the thread until the timeout is reached.
 		       Then return ETIMEDOUT.  */
-		    struct timespec reltime;
-		    struct timespec now;
-
-		    INTERNAL_SYSCALL (clock_gettime, __err, 2, clockid,
-				      &now);
-		    reltime.tv_sec = abstime->tv_sec - now.tv_sec;
-		    reltime.tv_nsec = abstime->tv_nsec - now.tv_nsec;
-		    if (reltime.tv_nsec < 0)
-		      {
-			reltime.tv_nsec += 1000000000;
-			--reltime.tv_sec;
-		      }
-		    if (reltime.tv_sec >= 0)
-		      while (__nanosleep_nocancel (&reltime, &reltime) != 0)
-			continue;
-
+		    do
+		      e = lll_timedwait (&(int){0}, 0, clockid, abstime,
+					 private);
+		    while (e != ETIMEDOUT);
 		    return ETIMEDOUT;
 		  }