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linux: Only use 64-bit syscall if required for sigtimedwait

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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>
This commit is contained in:
Adhemerval Zanella
2021-06-16 09:58:29 -03:00
parent 1faff27011
commit dafab287b4
3 changed files with 36 additions and 9 deletions
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25
sysdeps/unix/sysv/linux/sigtimedwait.c
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@@ -25,20 +25,27 @@ __sigtimedwait64 (const sigset_t *set, siginfo_t *info,
#ifndef __NR_rt_sigtimedwait_time64
# define __NR_rt_sigtimedwait_time64 __NR_rt_sigtimedwait
#endif
int result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
__NSIG_BYTES);
#ifndef __ASSUME_TIME64_SYSCALLS
if (result != 0 && errno == ENOSYS)
int result;
#ifdef __ASSUME_TIME64_SYSCALLS
result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
__NSIG_BYTES);
#else
bool need_time64 = timeout != NULL && !in_time_t_range (timeout->tv_sec);
if (need_time64)
{
result = SYSCALL_CANCEL (rt_sigtimedwait_time64, set, info, timeout,
__NSIG_BYTES);
if (result == 0 || errno != ENOSYS)
return result;
__set_errno (EOVERFLOW);
return -1;
}
else
{
struct timespec ts32, *pts32 = NULL;
if (timeout != NULL)
{
if (! in_time_t_range (timeout->tv_sec))
{
__set_errno (EINVAL);
return -1;
}
ts32 = valid_timespec64_to_timespec (*timeout);
pts32 = &ts32;
}