rt_sigtimedwait

synchronously wait for queued signals

sys_rt_sigtimedwait_time32(const sigset_t *uthese, siginfo_t *uinfo, const struct old_timespec32 *uts, size_t sigsetsize)

register	value
`v0`	4197, the syscall number
`a0`	const sigset_t *uthese
`a1`	siginfo_t *uinfo
`a2`	const struct old_timespec32 *uts
`a3`	size_t sigsetsize
`v0`	the return value

Then run syscall to enter the kernel.

Same syscall on other architectures