arm64: Change kernel stack size to 16K

commit 845ad05e upstream.

Written by Catalin Marinas, tested by APM on storm platform. This is needed
because of the failures encountered when running SpecWeb benchmark test.
Signed-off-by: Feng Kan <fkan@apm.com>
Acked-by: Kumar Sankaran <ksankaran@apm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/arm64/include/asm/thread_info.h

@@ -24,10 +24,10 @@
 #include <linux/compiler.h>
 
 #ifndef CONFIG_ARM64_64K_PAGES
-#define THREAD_SIZE_ORDER	1
+#define THREAD_SIZE_ORDER	2
 #endif
 
-#define THREAD_SIZE		8192
+#define THREAD_SIZE		16384
 #define THREAD_START_SP		(THREAD_SIZE - 16)
 
 #ifndef __ASSEMBLY__

arch/arm64/kernel/entry.S

@@ -121,7 +121,7 @@
 
 	.macro	get_thread_info, rd
 	mov	\rd, sp
-	and	\rd, \rd, #~((1 << 13) - 1)	// top of 8K stack
+	and	\rd, \rd, #~(THREAD_SIZE - 1)	// top of stack
 	.endm
 
 /*