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authorLukasz Majewski <lukma@denx.de>2020-09-18 20:54:13 +0200
committerLukasz Majewski <lukma@denx.de>2020-10-15 09:35:43 +0200
commit29e9874a048f47e2d46c40253036c8d2de921548 (patch)
tree89bf596e3db06ad009bca5ba0b5ee947732d8f68 /sysdeps/nptl
parent9ebaabeaac1a96b0d91f52902ce1dbf4f5a562dd (diff)
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y2038: nptl: Convert pthread_mutex_{clock|timed}lock to support 64 bit
The pthread_mutex_clocklock and pthread_mutex_timedlock have been converted to support 64 bit time. This change uses: - New __futex_clocklock_wait64 (instead of lll_timedwait) from ./sysdeps/nptl/futex-helpers.c and - New __futex_clocklock64 function (instead of lll_clocklock) - New futex_lock_pi64 defined in sysdeps/nptl/futex-internal.h The pthread_mutex_{clock|timed}lock only accepts absolute time. Moreover, there is no need to check for NULL passed as *abstime pointer to the syscalls as those calls have exported symbols marked with __nonull attribute for abstime. Some architectures - namely x86, powerpc and s390 - do support lock elision. For those - adjustments have been made in arch specific elision-*.c files to use __futex_clocklock64 instead of lll_clocklock. The __lll_lock_elision (aliased to __lll_clocklock_elision in e.g. sysdeps/unix/sysv/linux/s390/elision-timed.c) just uses, in this patch provided, __futex_clocklock64. For systems with __TIMESIZE != 64 && __WORDSIZE == 32: - Conversions between 64 bit time to 32 bit are necessary - Redirection to pthread_mutex_{clock|timed}lock will provide support for 64 bit time Build tests: ./src/scripts/build-many-glibcs.py glibcs Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/nptl')
-rw-r--r--sysdeps/nptl/futex-internal.c53
-rw-r--r--sysdeps/nptl/futex-internal.h72
2 files changed, 123 insertions, 2 deletions
diff --git a/sysdeps/nptl/futex-internal.c b/sysdeps/nptl/futex-internal.c
index f418ed2dbb..2e1919f056 100644
--- a/sysdeps/nptl/futex-internal.c
+++ b/sysdeps/nptl/futex-internal.c
@@ -169,3 +169,56 @@ __futex_abstimed_wait64 (unsigned int* futex_word, unsigned int expected,
futex_fatal_error ();
}
}
+
+int
+__futex_clocklock_wait64 (int *futex, int val, clockid_t clockid,
+ const struct __timespec64 *abstime, int private)
+{
+ struct __timespec64 ts, *tsp = NULL;
+
+ if (abstime != NULL)
+ {
+ /* Reject invalid timeouts. */
+ if (! valid_nanoseconds (abstime->tv_nsec))
+ return EINVAL;
+
+ /* Get the current time. This can only fail if clockid is not valid. */
+ if (__glibc_unlikely (__clock_gettime64 (clockid, &ts) != 0))
+ return EINVAL;
+
+ /* Compute relative timeout. */
+ ts.tv_sec = abstime->tv_sec - ts.tv_sec;
+ ts.tv_nsec = abstime->tv_nsec - ts.tv_nsec;
+ if (ts.tv_nsec < 0)
+ {
+ ts.tv_nsec += 1000000000;
+ --ts.tv_sec;
+ }
+
+ if (ts.tv_sec < 0)
+ return ETIMEDOUT;
+
+ tsp = &ts;
+ }
+
+ int err = INTERNAL_SYSCALL_CALL (futex_time64, futex,
+ __lll_private_flag (FUTEX_WAIT, private),
+ val, tsp);
+#ifndef __ASSUME_TIME64_SYSCALLS
+ if (err == -ENOSYS)
+ {
+ if (tsp != NULL && ! in_time_t_range (tsp->tv_sec))
+ return EOVERFLOW;
+
+ struct timespec ts32;
+ if (tsp != NULL)
+ ts32 = valid_timespec64_to_timespec (*tsp);
+
+ err = INTERNAL_SYSCALL_CALL (futex, futex,
+ __lll_private_flag (FUTEX_WAIT, private),
+ val, tsp != NULL ? &ts32 : NULL);
+ }
+#endif
+
+ return -err;
+}
diff --git a/sysdeps/nptl/futex-internal.h b/sysdeps/nptl/futex-internal.h
index 1ba0d61938..8a5f62768f 100644
--- a/sysdeps/nptl/futex-internal.h
+++ b/sysdeps/nptl/futex-internal.h
@@ -437,6 +437,51 @@ futex_lock_pi (unsigned int *futex_word, const struct timespec *abstime,
}
}
+static __always_inline int
+futex_lock_pi64 (int *futex_word, const struct __timespec64 *abstime,
+ int private)
+{
+ int err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
+ __lll_private_flag
+ (FUTEX_LOCK_PI, private), 0, abstime);
+#ifndef __ASSUME_TIME64_SYSCALLS
+ if (err == -ENOSYS)
+ {
+ if (abstime != NULL && ! in_time_t_range (abstime->tv_sec))
+ return EOVERFLOW;
+
+ struct timespec ts32;
+ if (abstime != NULL)
+ ts32 = valid_timespec64_to_timespec (*abstime);
+
+ err = INTERNAL_SYSCALL_CALL (futex, futex_word, __lll_private_flag
+ (FUTEX_LOCK_PI, private), 0,
+ abstime != NULL ? &ts32 : NULL);
+ }
+#endif
+ switch (err)
+ {
+ case 0:
+ case -EAGAIN:
+ case -EINTR:
+ case -ETIMEDOUT:
+ case -ESRCH:
+ case -EDEADLK:
+ case -EINVAL: /* This indicates either state corruption or that the kernel
+ found a waiter on futex address which is waiting via
+ FUTEX_WAIT or FUTEX_WAIT_BITSET. This is reported on
+ some futex_lock_pi usage (pthread_mutex_timedlock for
+ instance). */
+ return -err;
+
+ case -EFAULT: /* 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. */
+ default:
+ futex_fatal_error ();
+ }
+}
+
/* Wakes the top priority waiter that called a futex_lock_pi operation on
the futex.
@@ -476,8 +521,8 @@ futex_timed_wait_cancel64 (pid_t *tidp, pid_t tid,
const struct __timespec64 *timeout, int private)
{
int err = INTERNAL_SYSCALL_CANCEL (futex_time64, tidp,
- __lll_private_flag
- (FUTEX_WAIT, private), tid, timeout);
+ __lll_private_flag (FUTEX_WAIT, private),
+ tid, timeout);
#ifndef __ASSUME_TIME64_SYSCALLS
if (err == -ENOSYS)
{
@@ -535,4 +580,27 @@ __futex_abstimed_wait64 (unsigned int* futex_word, unsigned int expected,
const struct __timespec64* abstime,
int private) attribute_hidden;
+int
+__futex_clocklock_wait64 (int *futex, int val, clockid_t clockid,
+ const struct __timespec64 *abstime,
+ int private) attribute_hidden;
+
+static __always_inline int
+__futex_clocklock64 (int *futex, clockid_t clockid,
+ const struct __timespec64 *abstime, int private)
+{
+ int err = 0;
+
+ if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 1, 0)))
+ {
+ while (atomic_exchange_acq (futex, 2) != 0)
+ {
+ err = __futex_clocklock_wait64 (futex, 2, clockid, abstime, private);
+ if (err == EINVAL || err == ETIMEDOUT || err == EOVERFLOW)
+ break;
+ }
+ }
+ return err;
+}
+
#endif /* futex-internal.h */