kexec_load

load a new kernel for later execution

sys_kexec_load(unsigned long entry, unsigned long nr_segments, struct kexec_segment *segments, unsigned long flags)

register	value
`r6`	104, the syscall number
`r0`	unsigned long entry
`r1`	unsigned long nr_segments
`r2`	struct kexec_segment *segments
`r3`	unsigned long flags
`r0`	the return value

Then run trap0(#1) to enter the kernel.

Same syscall on other architectures