!353 [openEuler-22.09] machine check safe review issue modification

Merge Pull Request from: @Tong-Tiangen 
 
https://gitee.com/openeuler/kernel/issues/I6AQE8 
 
Link:https://gitee.com/openeuler/kernel/pulls/353 

Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> 
Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com> 
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> 
Acked-by: Zheng Zengkai <zhengzengkai@huawei.com> 

arch/arm64/include/asm/string.h

@@ -36,8 +36,8 @@ extern void *memcpy(void *, const void *, __kernel_size_t);
 extern void *__memcpy(void *, const void *, __kernel_size_t);
 
 #define __HAVE_ARCH_MEMCPY_MC
-extern unsigned long *memcpy_mcs(void *, const void *, __kernel_size_t);
-extern unsigned long *__memcpy_mcs(void *, const void *, __kernel_size_t);
+extern unsigned long memcpy_mcs(void *, const void *, __kernel_size_t);
+extern unsigned long __memcpy_mcs(void *, const void *, __kernel_size_t);
 
 #define __HAVE_ARCH_MEMMOVE
 extern void *memmove(void *, const void *, __kernel_size_t);

mm/kasan/common.c

@@ -109,6 +109,18 @@ void *memcpy(void *dest, const void *src, size_t len)
 	return __memcpy(dest, src, len);
 }
 
+#ifdef __HAVE_ARCH_MEMCPY_MC
+#undef memcpy_mcs
+unsigned long memcpy_mcs(void *dest, const void *src, size_t len)
+{
+	if (!check_memory_region((unsigned long)src, len, false, _RET_IP_) ||
+	    !check_memory_region((unsigned long)dest, len, true, _RET_IP_))
+		return (unsigned long)len;
+
+	return __memcpy_mcs(dest, src, len);
+}
+#endif
+
 /*
  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
  * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.