From: Cheng Jian <cj.chengjian@huawei.com> hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4K6CJ CVE: NA -------------------------------- We must ensure that the following four instructions are cache-aligned. Otherwise, it will cause problems with the performance of libMicro pread. 1: # uao_user_alternative 9f, str, sttr, xzr, x0, 8 str xzr, [x0], #8 nop subs x1, x1, #8 b.pl 1b with this patch: prc thr usecs/call samples errors cnt/samp size pread_z100 1 1 5.88400 807 0 1 102400 The result of pread can range from 5 to 9 depending on the alignment performance of this function. Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- arch/arm64/lib/clear_user.S | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S index 48a3a26eff66..db74e9ff1e20 100644 --- a/arch/arm64/lib/clear_user.S +++ b/arch/arm64/lib/clear_user.S @@ -23,6 +23,9 @@ SYM_FUNC_START(__arch_clear_user) mov x2, x1 // save the size for fixup return subs x1, x1, #8 b.mi 2f +#ifdef CONFIG_ARCH_HISI + .align 5 +#endif 1: uao_user_alternative 9f, str, sttr, xzr, x0, 8 subs x1, x1, #8 -- 2.20.1