since xcpt always point to the stack after the below change:
commit 7b9978883c46569068ba5dac5755f998fbd237b2
Author: chao.an <anchao@xiaomi.com>
Date: Tue Mar 1 01:06:24 2022 +0800
arch/arm: optimize context switch speed
The current context save implementation saves registers of each task
to xcp context, which is unnecessary because most of the arm registers are
already saved in the task stack, this commit replace the xcp context with
stack context to improve context switching performance and reduce the tcb
space occupation of tcb instance.
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
9ae0dcd4a2