livepatch: checks only if the replaced instruction is on the stack

hulk inclusion
category: feature
bugzilla: 119440 https://gitee.com/openeuler/kernel/issues/I4DDEL



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When the CONFIG_LIVEPATCH_STOP_MACHINE_CONSISTENCY macro is turned
on, the system checks whether the function to patch is on the stack
under the stop_machine. If the function is on the stack, the livepatch
cannot be patched and returns a busy signal.

Hotspot functions are easily on the stack under the stop_machine
condition. As a result, the livpatch success rate is low when the
patch includes a hot function.

For the repalced function, only the first seceral instructions are
rewritten, and the rest of the instructions are the same as the
original ones. Therefore, if the force flag is KLP_STACK_OPTIMIZE,
only need to check whether the replaced instructions are on the
stack.

Signed-off-by: Ye Weihua <yeweihua4@huawei.com>
Reviewed-by: Kuohai Xu <xukuohai@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>