unify and overhaul timed futex waits

new features:

- FUTEX_WAIT_BITSET op will be used for timed waits if available. this
  saves a call to clock_gettime.

- error checking for the timespec struct is now inside __timedwait so
  it doesn't need to be duplicated everywhere. cond_timedwait still
  needs to duplicate it to avoid unlocking the mutex, though.

- pushing and popping the cancellation handler is delegated to
  __timedwait, and cancellable/non-cancellable waits are unified.

2 files changed, 4 insertions, 2 deletions

diff --git a/src/internal/futex.h b/src/internal/futex.h
index c0453822..d7bf2b7d 100644
--- a/src/internal/futex.h
+++ b/src/internal/futex.h
@@ -10,6 +10,9 @@
 #define FUTEX_LOCK_PI		6
 #define FUTEX_UNLOCK_PI		7
 #define FUTEX_TRYLOCK_PI	8
+#define FUTEX_WAIT_BITSET	9
+
+#define FUTEX_CLOCK_REALTIME 256
 
 int __futex(volatile int *, int, int, void *);
 
diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 03af4c12..c11840d6 100644
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -95,8 +95,7 @@ int __libc_sigprocmask(int, const sigset_t *, sigset_t *);
 void __lock(volatile int *);
 void __unmapself(void *, size_t);
 
-int __timedwait(volatile int *, int, clockid_t, const struct timespec *, int);
-int __timedwait_cp(volatile int *, int, clockid_t, const struct timespec *, int);
+int __timedwait(volatile int *, int, clockid_t, const struct timespec *, void (*)(void *), void *, int);
 void __wait(volatile int *, volatile int *, int, int);
 void __wake(volatile int *, int, int);