nptl: Add clockid parameter to futex timed wait calls

In preparation for adding POSIX clockwait variants of timedwait functions,
add a clockid_t parameter to futex_abstimed_wait functions and pass
CLOCK_REALTIME from all callers for the time being.

Replace lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset
which takes a clockid_t parameter rather than the magic clockbit.

	* sysdeps/nptl/lowlevellock-futex.h,
	sysdeps/unix/sysv/linux/lowlevellock-futex.h: Replace
	lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset that
	takes a clockid rather than a special clockbit.
	* sysdeps/nptl/lowlevellock-futex.h: Add
	lll_futex_supported_clockid so that client functions can check
	whether their clockid parameter is valid even if they don't
	ultimately end up calling lll_futex_clock_wait_bitset.
	* sysdeps/nptl/futex-internal.h,
	sysdeps/unix/sysv/linux/futex-internal.h
	(futex_abstimed_wait, futex_abstimed_wait_cancelable): Add
	clockid_t parameter to indicate which clock the absolute time
	passed should be measured against. Pass that clockid onto
	lll_futex_clock_wait_bitset. Add invalid clock as reason for
	returning -EINVAL.
	* sysdeps/nptl/futex-internal.h,
	sysdeps/unix/sysv/linux/futex-internal.h: Introduce
	futex_abstimed_supported_clockid so that client functions can check
	whether their clockid parameter is valid even if they don't
	ultimately end up calling futex_abstimed_wait.
	* nptl/pthread_cond_wait.c (__pthread_cond_wait_common): Remove
	code to calculate relative timeout for
	__PTHREAD_COND_CLOCK_MONOTONIC_MASK and just pass CLOCK_MONOTONIC
	or CLOCK_REALTIME as required to futex_abstimed_wait_cancelable.
	* nptl/pthread_rwlock_common (__pthread_rwlock_rdlock_full)
	(__pthread_wrlock_full), nptl/sem_waitcommon (do_futex_wait): Pass
	additional CLOCK_REALTIME to futex_abstimed_wait_cancelable.
	* nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock):
	Switch to lll_futex_clock_wait_bitset and pass CLOCK_REALTIME

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

2 files changed, 17 insertions, 5 deletions

diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h
index 86a0818072..f29d6d48b2 100644
--- a/sysdeps/nptl/futex-internal.h
+++ b/sysdeps/nptl/futex-internal.h
@@ -49,7 +49,7 @@
    futex word.
 
    Both absolute and relative timeouts can be used.  An absolute timeout
-   expires when the given specific point in time on the CLOCK_REALTIME clock
+   expires when the given specific point in time on the specified clock
    passes, or when it already has passed.  A relative timeout expires when
    the given duration of time on the CLOCK_MONOTONIC clock passes.  Relative
    timeouts may be imprecise (see futex_supports_exact_relative_timeouts).
@@ -159,16 +159,23 @@ futex_reltimed_wait_cancelable (unsigned int* futex_word,
 				unsigned int expected,
 			        const struct timespec* reltime, int private);
 
+/* Check whether the specified clockid is supported by
+   futex_abstimed_wait and futex_abstimed_wait_cancelable.  */
+static __always_inline int
+futex_abstimed_supported_clockid (clockid_t clockid);
+
 /* Like futex_reltimed_wait, but the provided timeout (ABSTIME) is an
    absolute point in time; a call will time out after this point in time.  */
 static __always_inline int
 futex_abstimed_wait (unsigned int* futex_word, unsigned int expected,
+		     clockid_t clockid,
 		     const struct timespec* abstime, int private);
 
 /* Like futex_reltimed_wait but is a POSIX cancellation point.  */
 static __always_inline int
 futex_abstimed_wait_cancelable (unsigned int* futex_word,
 				unsigned int expected,
+				clockid_t clockid,
 			        const struct timespec* abstime, int private);
 
 /* Atomically wrt other futex operations on the same futex, this unblocks the
diff --git a/sysdeps/nptl/lowlevellock-futex.h b/sysdeps/nptl/lowlevellock-futex.h
index 63d917d8da..53fd53d1d4 100644
--- a/sysdeps/nptl/lowlevellock-futex.h
+++ b/sysdeps/nptl/lowlevellock-futex.h
@@ -43,10 +43,15 @@
 #define lll_futex_timed_wait(futexp, val, timeout, private)             \
   -ENOSYS
 
-/* If CLOCKBIT is zero, this is identical to lll_futex_timed_wait.
-   If CLOCKBIT has FUTEX_CLOCK_REALTIME set, then it's the same but
-   TIMEOUT is counted by CLOCK_REALTIME rather than CLOCK_MONOTONIC.  */
-#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
+/* Verify whether the supplied clockid is supported by
+   lll_futex_clock_wait_bitset.  */
+#define lll_futex_supported_clockid(clockid)				\
+  (0)
+
+/* Wait until a lll_futex_wake call on FUTEXP, or the absolute TIMEOUT
+   measured against CLOCKID elapses. CLOCKID may be CLOCK_REALTIME or
+   CLOCK_MONOTONIC.  */
+#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
   -ENOSYS
 
 /* Wake up up to NR waiters on FUTEXP.  */