timer_settime

arm/disarm and fetch state of POSIX per-process timer

sys_timer_settime(timer_t timer_id, int flags, const struct __kernel_itimerspec *new_setting, struct __kernel_itimerspec *old_setting)

register	value
`r0`	241, the syscall number
`r3`	timer_t timer_id
`r4`	int flags
`r5`	const struct __kernel_itimerspec *new_setting
`r6`	struct __kernel_itimerspec *old_setting
`r3`	the return value

Then run sc to enter the kernel.

Same syscall on other architectures