powerpc: In HV mode, use HSPRG0 for PACA

When running in Hypervisor mode (arch 2.06 or later), we store the PACA
in HSPRG0 instead of SPRG1. The architecture specifies that SPRGs may be
lost during a "nap" power management operation (though they aren't
currently on POWER7) and this enables use of SPRG1 by KVM guests.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 7778d6f..337b6fa 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -56,8 +56,8 @@
 #define LOAD_HANDLER(reg, label)					\
 	addi	reg,reg,(label)-_stext;	/* virt addr of handler ... */
 
-#define EXCEPTION_PROLOG_1(area)				\
-	mfspr	r13,SPRN_SPRG_PACA;	/* get paca address into r13 */	\
+#define EXCEPTION_PROLOG_1(area)					\
+	GET_PACA(r13);							\
 	std	r9,area+EX_R9(r13);	/* save r9 - r12 */		\
 	std	r10,area+EX_R10(r13);					\
 	std	r11,area+EX_R11(r13);					\
@@ -174,7 +174,7 @@
 	HMT_MEDIUM;							\
 	DO_KVM	n;							\
 	mtspr	SPRN_SPRG_SCRATCH0,r13;	/* save r13 */			\
-	mfspr	r13,SPRN_SPRG_PACA;	/* get paca address into r13 */	\
+	GET_PACA(r13);							\
 	std	r9,PACA_EXGEN+EX_R9(r13);	/* save r9, r10 */	\
 	std	r10,PACA_EXGEN+EX_R10(r13);				\
 	lbz	r10,PACASOFTIRQEN(r13);					\