Florian Bezdeka authored May 07, 2021 and Jan Kiszka committed May 09, 2021

On systems using 32 bit for time_t the sem_timedwait syscall was broken
because the function used for copying the timeout value from userspace
to kernel (=sem_fetch_timeout()) was always copying
sizeof(struct timespec64).

A 32 bit application (or more specific an application with 4 byte
time_t) would only provide sizeof(struct old_timespec32).

Notable changes:
  - The copy operation from userspace to kernel is now already done in
    the syscall handler. So it is always done and might fail. Reporting
    a failure is delayed until the timeout is being validated.

  - Validation: Switched to timespec64_valid() instead of our own
    check.

Signed-off-by: Florian Bezdeka <florian.bezdeka@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>