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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-06-25 10:11:00 +0200 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-10-01 08:09:13 -0300 |
commit | 8352b6df371f1d08f86b4600a7725a5181e021ee (patch) | |
tree | 39a3bed73cdf1ec4908fccb4401a83295b74b81c /nptl/futex-internal.c | |
parent | dd5adb515c105e4ad1619825babe85d75a7a755c (diff) | |
download | glibc-8352b6df371f1d08f86b4600a7725a5181e021ee.tar.gz glibc-8352b6df371f1d08f86b4600a7725a5181e021ee.tar.xz glibc-8352b6df371f1d08f86b4600a7725a5181e021ee.zip |
nptl: Use FUTEX_LOCK_PI2 when available
This patch uses the new futex PI operation provided by Linux v5.14 when it is required. The futex_lock_pi64() is moved to futex-internal.c (since it used on two different places and its code size might be large depending of the kernel configuration) and clockid is added as an argument. Co-authored-by: Kurt Kanzenbach <kurt@linutronix.de>
Diffstat (limited to 'nptl/futex-internal.c')
-rw-r--r-- | nptl/futex-internal.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/nptl/futex-internal.c b/nptl/futex-internal.c index e74647a9d4..58605b2fca 100644 --- a/nptl/futex-internal.c +++ b/nptl/futex-internal.c @@ -140,3 +140,66 @@ __futex_abstimed_wait_cancelable64 (unsigned int* futex_word, abstime, private, true); } libc_hidden_def (__futex_abstimed_wait_cancelable64) + +int +__futex_lock_pi64 (int *futex_word, clockid_t clockid, + const struct __timespec64 *abstime, int private) +{ + int err; + + unsigned int clockbit = clockid == CLOCK_REALTIME + ? FUTEX_CLOCK_REALTIME : 0; + int op_pi2 = __lll_private_flag (FUTEX_LOCK_PI2 | clockbit, private); +#if __ASSUME_FUTEX_LOCK_PI2 + /* Assume __ASSUME_TIME64_SYSCALLS since FUTEX_LOCK_PI2 was added later. */ + err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi2, 0, abstime); +#else + /* FUTEX_LOCK_PI does not support clock selection, so for CLOCK_MONOTONIC + the only option is to use FUTEX_LOCK_PI2. */ + int op_pi1 = __lll_private_flag (FUTEX_LOCK_PI, private); + int op_pi = abstime != NULL && clockid != CLOCK_REALTIME ? op_pi2 : op_pi1; + +# ifdef __ASSUME_TIME64_SYSCALLS + err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi, 0, abstime); +# else + bool need_time64 = abstime != NULL && !in_time_t_range (abstime->tv_sec); + if (need_time64) + err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi, 0, abstime); + else + { + struct timespec ts32, *pts32 = NULL; + if (abstime != NULL) + { + ts32 = valid_timespec64_to_timespec (*abstime); + pts32 = &ts32; + } + err = INTERNAL_SYSCALL_CALL (futex, futex_word, op_pi, 0, pts32); + } +# endif /* __ASSUME_TIME64_SYSCALLS */ + /* FUTEX_LOCK_PI2 is not available on this kernel. */ + if (err == -ENOSYS) + err = -EINVAL; +#endif /* __ASSUME_FUTEX_LOCK_PI2 */ + + 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 (); + } +} |