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author | Lukasz Majewski <lukma@denx.de> | 2020-09-18 20:54:13 +0200 |
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committer | Lukasz Majewski <lukma@denx.de> | 2020-10-15 09:35:43 +0200 |
commit | 29e9874a048f47e2d46c40253036c8d2de921548 (patch) | |
tree | 89bf596e3db06ad009bca5ba0b5ee947732d8f68 /sysdeps/nptl | |
parent | 9ebaabeaac1a96b0d91f52902ce1dbf4f5a562dd (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.c | 53 | ||||
-rw-r--r-- | sysdeps/nptl/futex-internal.h | 72 |
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 */ |