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glibc/backport-0002-nptl-Add-clockid-parameter-to-futex-timed-wait-calls.patch
xuhuijie 41e37c0975 pthread_cond_clockwait: add pre-patch to prevent adaptions 
(cherry picked from commit f56ebf8358af3a352d6a7bf1eae27eae9ccebcbe)
2021-05-14 08:50:25 +08:00

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From 99d01ffcc386d1bfb681fb0684fcf6a6a996beb3 Mon Sep 17 00:00:00 2001
From: Mike Crowe <mac@mcrowe.com>
Date: Fri, 21 Jun 2019 14:53:40 +0000
Subject: [PATCH] nptl: Add clockid parameter to futex timed wait calls
Conflict:NA
Reference:https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=99d01ffcc386d1bfb681fb0684fcf6a6a996beb3
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>
---
ChangeLog | 33 ++++++++++++++++++++
nptl/pthread_cond_wait.c | 32 ++++---------------
nptl/pthread_mutex_timedlock.c | 4 +--
nptl/pthread_rwlock_common.c | 8 ++---
nptl/sem_waitcommon.c | 6 ++--
sysdeps/nptl/futex-internal.h | 9 +++++-
sysdeps/nptl/lowlevellock-futex.h | 13 ++++++---
sysdeps/unix/sysv/linux/futex-internal.h | 24 ++++++++++----
sysdeps/unix/sysv/linux/lowlevellock-futex.h | 32 +++++++++++++++----
9 files changed, 110 insertions(+), 51 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 24a97096..1f8cf24f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,36 @@
+2019-07-12 Mike Crowe <mac@mcrowe.com>
+
+ nptl: Add clockid parameter to futex timed wait calls
+ * 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
+
2019-03-05 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl/nptl-init.c (__have_futex_clock_realtime,
diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
index 3e110541..3294fa3a 100644
--- a/nptl/pthread_cond_wait.c
+++ b/nptl/pthread_cond_wait.c
@@ -509,35 +509,15 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
values despite them being valid. */
if (__glibc_unlikely (abstime->tv_sec < 0))
err = ETIMEDOUT;
-
- else if ((flags & __PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0)
- {
- /* CLOCK_MONOTONIC is requested. */
- struct timespec rt;
- if (__clock_gettime (CLOCK_MONOTONIC, &rt) != 0)
- __libc_fatal ("clock_gettime does not support "
- "CLOCK_MONOTONIC");
- /* Convert the absolute timeout value to a relative
- timeout. */
- rt.tv_sec = abstime->tv_sec - rt.tv_sec;
- rt.tv_nsec = abstime->tv_nsec - rt.tv_nsec;
- if (rt.tv_nsec < 0)
- {
- rt.tv_nsec += 1000000000;
- --rt.tv_sec;
- }
- /* Did we already time out? */
- if (__glibc_unlikely (rt.tv_sec < 0))
- err = ETIMEDOUT;
- else
- err = futex_reltimed_wait_cancelable
- (cond->__data.__g_signals + g, 0, &rt, private);
- }
else
{
- /* Use CLOCK_REALTIME. */
+ const clockid_t clockid =
+ ((flags & __PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0) ?
+ CLOCK_MONOTONIC : CLOCK_REALTIME;
+
err = futex_abstimed_wait_cancelable
- (cond->__data.__g_signals + g, 0, abstime, private);
+ (cond->__data.__g_signals + g, 0, clockid, abstime,
+ private);
}
}
diff --git a/nptl/pthread_mutex_timedlock.c b/nptl/pthread_mutex_timedlock.c
index 888c12fe..46fcf8d8 100644
--- a/nptl/pthread_mutex_timedlock.c
+++ b/nptl/pthread_mutex_timedlock.c
@@ -292,8 +292,8 @@ __pthread_mutex_timedlock (pthread_mutex_t *mutex,
assume_other_futex_waiters |= FUTEX_WAITERS;
/* Block using the futex. */
- int err = lll_futex_timed_wait_bitset (&mutex->__data.__lock,
- oldval, abstime, FUTEX_CLOCK_REALTIME,
+ int err = lll_futex_clock_wait_bitset (&mutex->__data.__lock,
+ oldval, CLOCK_REALTIME, abstime,
PTHREAD_ROBUST_MUTEX_PSHARED (mutex));
/* The futex call timed out. */
if (err == -ETIMEDOUT)
diff --git a/nptl/pthread_rwlock_common.c b/nptl/pthread_rwlock_common.c
index 597a8532..1918f7c9 100644
--- a/nptl/pthread_rwlock_common.c
+++ b/nptl/pthread_rwlock_common.c
@@ -319,7 +319,7 @@ __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
{
int private = __pthread_rwlock_get_private (rwlock);
int err = futex_abstimed_wait (&rwlock->__data.__readers,
- r, abstime, private);
+ r, CLOCK_REALTIME, abstime, private);
/* We ignore EAGAIN and EINTR. On time-outs, we can just
return because we don't need to clean up anything. */
if (err == ETIMEDOUT)
@@ -444,7 +444,7 @@ __pthread_rwlock_rdlock_full (pthread_rwlock_t *rwlock,
&wpf, wpf | PTHREAD_RWLOCK_FUTEX_USED))
continue;
int err = futex_abstimed_wait (&rwlock->__data.__wrphase_futex,
- 1 | PTHREAD_RWLOCK_FUTEX_USED, abstime, private);
+ 1 | PTHREAD_RWLOCK_FUTEX_USED, CLOCK_REALTIME, abstime, private);
if (err == ETIMEDOUT)
{
/* If we timed out, we need to unregister. If no read phase
@@ -704,7 +704,7 @@ __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
in this group. */
may_share_futex_used_flag = true;
int err = futex_abstimed_wait (&rwlock->__data.__writers_futex,
- 1 | PTHREAD_RWLOCK_FUTEX_USED, abstime, private);
+ 1 | PTHREAD_RWLOCK_FUTEX_USED, CLOCK_REALTIME, abstime, private);
if (err == ETIMEDOUT)
{
if (prefer_writer)
@@ -801,7 +801,7 @@ __pthread_rwlock_wrlock_full (pthread_rwlock_t *rwlock,
PTHREAD_RWLOCK_FUTEX_USED))
continue;
int err = futex_abstimed_wait (&rwlock->__data.__wrphase_futex,
- PTHREAD_RWLOCK_FUTEX_USED, abstime, private);
+ PTHREAD_RWLOCK_FUTEX_USED, CLOCK_REALTIME, abstime, private);
if (err == ETIMEDOUT)
{
if (rwlock->__data.__flags
diff --git a/nptl/sem_waitcommon.c b/nptl/sem_waitcommon.c
index 30984be2..1811a32c 100644
--- a/nptl/sem_waitcommon.c
+++ b/nptl/sem_waitcommon.c
@@ -109,11 +109,13 @@ do_futex_wait (struct new_sem *sem, const struct timespec *abstime)
#if __HAVE_64B_ATOMICS
err = futex_abstimed_wait_cancelable (
- (unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0, abstime,
+ (unsigned int *) &sem->data + SEM_VALUE_OFFSET, 0,
+ CLOCK_REALTIME, abstime,
sem->private);
#else
err = futex_abstimed_wait_cancelable (&sem->value, SEM_NWAITERS_MASK,
- abstime, sem->private);
+ CLOCK_REALTIME, abstime,
+ sem->private);
#endif
return err;
diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h
index 1a562478..353fdfb9 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 27b81b83..68ce7516 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. */
diff --git a/sysdeps/unix/sysv/linux/futex-internal.h b/sysdeps/unix/sysv/linux/futex-internal.h
index 96a07b05..8023cb85 100644
--- a/sysdeps/unix/sysv/linux/futex-internal.h
+++ b/sysdeps/unix/sysv/linux/futex-internal.h
@@ -160,17 +160,26 @@ futex_reltimed_wait_cancelable (unsigned int *futex_word,
}
}
+/* See sysdeps/nptl/futex-internal.h for details. */
+static __always_inline int
+futex_abstimed_supported_clockid (clockid_t clockid)
+{
+ return lll_futex_supported_clockid (clockid);
+}
+
/* See sysdeps/nptl/futex-internal.h for details. */
static __always_inline int
futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
+ clockid_t clockid,
const struct timespec *abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
despite them being valid. */
if (__glibc_unlikely ((abstime != NULL) && (abstime->tv_sec < 0)))
return ETIMEDOUT;
- int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
- FUTEX_CLOCK_REALTIME, private);
+ int err = lll_futex_clock_wait_bitset (futex_word, expected,
+ clockid, abstime,
+ private);
switch (err)
{
case 0:
@@ -180,8 +189,9 @@ futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
- case -EINVAL: /* Either due to wrong alignment or due to the timeout not
- being normalized. Must have been caused by a glibc or
+ case -EINVAL: /* Either due to wrong alignment, unsupported
+ clockid or due to the timeout not being
+ normalized. Must have been caused by a glibc or
application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
@@ -194,6 +204,7 @@ futex_abstimed_wait (unsigned int *futex_word, unsigned int expected,
static __always_inline int
futex_abstimed_wait_cancelable (unsigned int *futex_word,
unsigned int expected,
+ clockid_t clockid,
const struct timespec *abstime, int private)
{
/* Work around the fact that the kernel rejects negative timeout values
@@ -202,8 +213,9 @@ futex_abstimed_wait_cancelable (unsigned int *futex_word,
return ETIMEDOUT;
int oldtype;
oldtype = __pthread_enable_asynccancel ();
- int err = lll_futex_timed_wait_bitset (futex_word, expected, abstime,
- FUTEX_CLOCK_REALTIME, private);
+ int err = lll_futex_clock_wait_bitset (futex_word, expected,
+ clockid, abstime,
+ private);
__pthread_disable_asynccancel (oldtype);
switch (err)
{
diff --git a/sysdeps/unix/sysv/linux/lowlevellock-futex.h b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
index fc834ed1..337faf1e 100644
--- a/sysdeps/unix/sysv/linux/lowlevellock-futex.h
+++ b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
@@ -82,12 +82,32 @@
__lll_private_flag (FUTEX_WAIT, private), \
val, timeout)
-#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
- lll_futex_syscall (6, futexp, \
- __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \
- private), \
- val, timeout, NULL /* Unused. */, \
- FUTEX_BITSET_MATCH_ANY)
+/* Verify whether the supplied clockid is supported by
+ lll_futex_clock_wait_bitset. */
+#define lll_futex_supported_clockid(clockid) \
+ ((clockid) == CLOCK_REALTIME || (clockid) == CLOCK_MONOTONIC)
+
+/* The kernel currently only supports CLOCK_MONOTONIC or
+ CLOCK_REALTIME timeouts for FUTEX_WAIT_BITSET. We could attempt to
+ convert others here but currently do not. */
+#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
+ ({ \
+ long int __ret; \
+ if (lll_futex_supported_clockid (clockid)) \
+ { \
+ const unsigned int clockbit = \
+ (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0; \
+ const int op = \
+ __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private); \
+ \
+ __ret = lll_futex_syscall (6, futexp, op, val, \
+ timeout, NULL /* Unused. */, \
+ FUTEX_BITSET_MATCH_ANY); \
+ } \
+ else \
+ __ret = -EINVAL; \
+ __ret; \
+ })
#define lll_futex_wake(futexp, nr, private) \
lll_futex_syscall (4, futexp, \
--
2.23.0
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