livepatch: Fix crash when access the global variable in hook

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8MGE6


CVE: NA

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Livepatch allows users to call hook functions to perform some customized
operations when insmod the .ko. During the test, it is found that in the
ARM64 architecture, if accesses the global variables defined by other ko in
hook functions, a crash occurs.

Since relocation is performed during the livepatch insertion, instructions
in the icache should be invalid. If the instructions in the icache are
directly obtained, incorrect addresses may be obtained, caseing crash.
Therefore, flush the icache before calling the hook functions.

Signed-off-by: Ye Weihua <yeweihua4@huawei.com>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>