powerpc/64s: Add EX_SIZE definition for paca exception save areas

Rather than open-coding it 4 times.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move __ASSEMBLY__ guards into head-64.h where they're really needed]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 33473cb..9f7f9be 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -36,6 +36,7 @@
  */
 #include <asm/head-64.h>
 
+/* PACA save area offsets (exgen, exmc, etc) */
 #define EX_R9		0
 #define EX_R10		8
 #define EX_R11		16
@@ -51,6 +52,8 @@
 #define EX_PPR		88	/* SMT thread status register (priority) */
 #define EX_CTR		96
 
+#define EX_SIZE		13	/* size in u64 units */
+
 #ifdef CONFIG_RELOCATABLE
 #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h)			\
 	mfspr	r11,SPRN_##h##SRR0;	/* save SRR0 */			\