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
`r20`	177, the syscall number
`r26`	const sigset_t *uthese
`r25`	siginfo_t *uinfo
`r24`	const struct old_timespec32 *uts
`r23`	size_t sigsetsize
`r28`	the return value

Then run ble 0x100(%sr2, %r0) to enter the kernel.

Same syscall on other architectures