From: Cheng Jian cj.chengjian@huawei.com
hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I3OX0C CVE: NA
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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 Reviewed-by: Xie XiuQi xiexiuqi@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/arm64/lib/clear_user.S | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S index 9ebc5d84e6154..410768a8d4166 100644 --- a/arch/arm64/lib/clear_user.S +++ b/arch/arm64/lib/clear_user.S @@ -20,7 +20,7 @@ #include <asm/asm-uaccess.h>
.text - .align 6 + /* Prototype: int __arch_clear_user(void *addr, size_t sz) * Purpose : clear some user memory * Params : addr - user memory address to clear @@ -34,6 +34,9 @@ ENTRY(__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