arm64: Implement support for read-mostly sections

As putting data which is read mostly together, we can avoid
unnecessary cache line bouncing.

Other architectures, such as ARM and x86, adopted the same idea.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NJungseok Lee <jungseoklee85@gmail.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/include/asm/cache.h

@@ -32,6 +32,8 @@
 
 #ifndef __ASSEMBLY__
 
+#define __read_mostly __attribute__((__section__(".data..read_mostly")))
+
 static inline int cache_line_size(void)
 {
 	u32 cwg = cache_type_cwg();