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linux: Only use 64-bit syscall if required for internal futex
For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall if the provided timeout fits in a 32-bit one. The 64-bit usage should be rare since the timeout is a relative one. Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel (with and without --enable-kernel=5.1) and on x86_64-linux-gnu. Reviewed-by: Lukasz Majewski <lukma@denx.de>
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@ -32,9 +32,6 @@ __futex_abstimed_wait_common32 (unsigned int* futex_word,
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struct timespec ts32, *pts32 = NULL;
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if (abstime != NULL)
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{
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if (! in_time_t_range (abstime->tv_sec))
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return -EOVERFLOW;
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ts32 = valid_timespec64_to_timespec (*abstime);
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pts32 = &ts32;
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}
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@ -52,12 +49,28 @@ __futex_abstimed_wait_common32 (unsigned int* futex_word,
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static int
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__futex_abstimed_wait_common64 (unsigned int* futex_word,
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unsigned int expected, clockid_t clockid,
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unsigned int expected, int op,
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const struct __timespec64* abstime,
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int private, bool cancel)
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{
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unsigned int clockbit;
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if (cancel)
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return INTERNAL_SYSCALL_CANCEL (futex_time64, futex_word, op, expected,
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abstime, NULL /* Unused. */,
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FUTEX_BITSET_MATCH_ANY);
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else
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return INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op, expected,
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abstime, NULL /* Ununsed. */,
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FUTEX_BITSET_MATCH_ANY);
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}
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static int
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__futex_abstimed_wait_common (unsigned int* futex_word,
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unsigned int expected, clockid_t clockid,
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const struct __timespec64* abstime,
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int private, bool cancel)
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{
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int err;
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unsigned int clockbit;
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/* Work around the fact that the kernel rejects negative timeout values
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despite them being valid. */
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@ -70,16 +83,19 @@ __futex_abstimed_wait_common64 (unsigned int* futex_word,
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clockbit = (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0;
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int op = __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private);
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if (cancel)
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err = INTERNAL_SYSCALL_CANCEL (futex_time64, futex_word, op, expected,
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abstime, NULL /* Unused. */,
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FUTEX_BITSET_MATCH_ANY);
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#ifdef __ASSUME_TIME64_SYSCALLS
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err = __futex_abstimed_wait_common64 (futex_word, expected, op, abstime,
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private, cancel);
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#else
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bool need_time64 = abstime != NULL && !in_time_t_range (abstime->tv_sec);
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if (need_time64)
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{
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err = __futex_abstimed_wait_common64 (futex_word, expected, op, abstime,
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private, cancel);
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if (err == -ENOSYS)
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err = -EOVERFLOW;
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}
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else
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err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op, expected,
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abstime, NULL /* Ununsed. */,
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FUTEX_BITSET_MATCH_ANY);
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#ifndef __ASSUME_TIME64_SYSCALLS
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if (err == -ENOSYS)
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err = __futex_abstimed_wait_common32 (futex_word, expected, op, abstime,
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private, cancel);
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#endif
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@ -109,8 +125,8 @@ __futex_abstimed_wait64 (unsigned int* futex_word, unsigned int expected,
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clockid_t clockid,
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const struct __timespec64* abstime, int private)
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{
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return __futex_abstimed_wait_common64 (futex_word, expected, clockid,
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abstime, private, false);
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return __futex_abstimed_wait_common (futex_word, expected, clockid,
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abstime, private, false);
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}
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libc_hidden_def (__futex_abstimed_wait64)
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@ -120,7 +136,7 @@ __futex_abstimed_wait_cancelable64 (unsigned int* futex_word,
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const struct __timespec64* abstime,
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int private)
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{
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return __futex_abstimed_wait_common64 (futex_word, expected, clockid,
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abstime, private, true);
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return __futex_abstimed_wait_common (futex_word, expected, clockid,
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abstime, private, true);
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}
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libc_hidden_def (__futex_abstimed_wait_cancelable64)
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@ -254,15 +254,23 @@ static __always_inline int
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futex_lock_pi64 (int *futex_word, const struct __timespec64 *abstime,
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int private)
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{
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int err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
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__lll_private_flag
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(FUTEX_LOCK_PI, private), 0, abstime);
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#ifndef __ASSUME_TIME64_SYSCALLS
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if (err == -ENOSYS)
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int err;
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#ifdef __ASSUME_TIME64_SYSCALLS
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err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
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__lll_private_flag (FUTEX_LOCK_PI, private), 0,
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abstime);
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#else
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bool need_time64 = abstime != NULL && !in_time_t_range (abstime->tv_sec);
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if (need_time64)
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{
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err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word,
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__lll_private_flag (FUTEX_LOCK_PI, private),
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0, abstime);
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if (err == -ENOSYS)
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err = -EOVERFLOW;
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}
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else
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{
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if (abstime != NULL && ! in_time_t_range (abstime->tv_sec))
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return EOVERFLOW;
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struct timespec ts32;
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if (abstime != NULL)
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ts32 = valid_timespec64_to_timespec (*abstime);
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