diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 2b03a09..bb845ee 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -319,7 +319,6 @@
 label##_pSeries:					\
 	HMT_MEDIUM;					\
 	mtspr	SPRN_SPRG1,r13;		/* save r13 */	\
-	RUNLATCH_ON(r13);				\
 	EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common)
 
 #define STD_EXCEPTION_ISERIES(n, label, area)		\
@@ -327,7 +326,6 @@
 label##_iSeries:					\
 	HMT_MEDIUM;					\
 	mtspr	SPRN_SPRG1,r13;		/* save r13 */	\
-	RUNLATCH_ON(r13);				\
 	EXCEPTION_PROLOG_ISERIES_1(area);		\
 	EXCEPTION_PROLOG_ISERIES_2;			\
 	b	label##_common
@@ -337,7 +335,6 @@
 label##_iSeries:							\
 	HMT_MEDIUM;							\
 	mtspr	SPRN_SPRG1,r13;		/* save r13 */			\
-	RUNLATCH_ON(r13);						\
 	EXCEPTION_PROLOG_ISERIES_1(PACA_EXGEN);				\
 	lbz	r10,PACAPROCENABLED(r13);				\
 	cmpwi	0,r10,0;						\
@@ -390,6 +387,7 @@
 label##_common:						\
 	EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);	\
 	DISABLE_INTS;					\
+	bl	.ppc64_runlatch_on;			\
 	addi	r3,r1,STACK_FRAME_OVERHEAD;		\
 	bl	hdlr;					\
 	b	.ret_from_except_lite
@@ -407,7 +405,6 @@
 _machine_check_pSeries:
 	HMT_MEDIUM
 	mtspr	SPRN_SPRG1,r13		/* save r13 */
-	RUNLATCH_ON(r13)
 	EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
 
 	. = 0x300
@@ -434,7 +431,6 @@
 data_access_slb_pSeries:
 	HMT_MEDIUM
 	mtspr	SPRN_SPRG1,r13
-	RUNLATCH_ON(r13)
 	mfspr	r13,SPRN_SPRG3		/* get paca address into r13 */
 	std	r3,PACA_EXSLB+EX_R3(r13)
 	mfspr	r3,SPRN_DAR
@@ -460,7 +456,6 @@
 instruction_access_slb_pSeries:
 	HMT_MEDIUM
 	mtspr	SPRN_SPRG1,r13
-	RUNLATCH_ON(r13)
 	mfspr	r13,SPRN_SPRG3		/* get paca address into r13 */
 	std	r3,PACA_EXSLB+EX_R3(r13)
 	mfspr	r3,SPRN_SRR0		/* SRR0 is faulting address */
@@ -491,7 +486,6 @@
 	.globl	system_call_pSeries
 system_call_pSeries:
 	HMT_MEDIUM
-	RUNLATCH_ON(r9)
 	mr	r9,r13
 	mfmsr	r10
 	mfspr	r13,SPRN_SPRG3
@@ -575,7 +569,6 @@
 system_reset_fwnmi:
 	HMT_MEDIUM
 	mtspr	SPRN_SPRG1,r13		/* save r13 */
-	RUNLATCH_ON(r13)
 	EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common)
 
 	.globl machine_check_fwnmi
@@ -583,7 +576,6 @@
 machine_check_fwnmi:
 	HMT_MEDIUM
 	mtspr	SPRN_SPRG1,r13		/* save r13 */
-	RUNLATCH_ON(r13)
 	EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
 
 #ifdef CONFIG_PPC_ISERIES
@@ -894,7 +886,6 @@
 	.align	7
 	.globl data_access_common
 data_access_common:
-	RUNLATCH_ON(r10)		/* It wont fit in the 0x300 handler */
 	mfspr	r10,SPRN_DAR
 	std	r10,PACA_EXGEN+EX_DAR(r13)
 	mfspr	r10,SPRN_DSISR
@@ -1042,6 +1033,7 @@
 	EXCEPTION_PROLOG_COMMON(0x500, PACA_EXGEN)
 hardware_interrupt_entry:
 	DISABLE_INTS
+	bl	.ppc64_runlatch_on
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	.do_IRQ
 	b	.ret_from_except_lite
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 5770399..c225cf1 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -888,3 +888,35 @@
 	show_stack(current, NULL);
 }
 EXPORT_SYMBOL(dump_stack);
+
+#ifdef CONFIG_PPC64
+void ppc64_runlatch_on(void)
+{
+	unsigned long ctrl;
+
+	if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
+		HMT_medium();
+
+		ctrl = mfspr(SPRN_CTRLF);
+		ctrl |= CTRL_RUNLATCH;
+		mtspr(SPRN_CTRLT, ctrl);
+
+		set_thread_flag(TIF_RUNLATCH);
+	}
+}
+
+void ppc64_runlatch_off(void)
+{
+	unsigned long ctrl;
+
+	if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) {
+		HMT_medium();
+
+		clear_thread_flag(TIF_RUNLATCH);
+
+		ctrl = mfspr(SPRN_CTRLF);
+		ctrl &= ~CTRL_RUNLATCH;
+		mtspr(SPRN_CTRLT, ctrl);
+	}
+}
+#endif
diff --git a/arch/powerpc/platforms/iseries/setup.c b/arch/powerpc/platforms/iseries/setup.c
index 3f87901..3ecc4a6 100644
--- a/arch/powerpc/platforms/iseries/setup.c
+++ b/arch/powerpc/platforms/iseries/setup.c
@@ -648,6 +648,7 @@
 	 * here and let the timer_interrupt code sort out the actual time.
 	 */
 	get_lppaca()->int_dword.fields.decr_int = 1;
+	ppc64_runlatch_on();
 	process_iSeries_events();
 }
 
diff --git a/include/asm-powerpc/reg.h b/include/asm-powerpc/reg.h
index 12ecc9b..72bfe3a 100644
--- a/include/asm-powerpc/reg.h
+++ b/include/asm-powerpc/reg.h
@@ -615,27 +615,9 @@
 #define proc_trap()	asm volatile("trap")
 
 #ifdef CONFIG_PPC64
-static inline void ppc64_runlatch_on(void)
-{
-	unsigned long ctrl;
 
-	if (cpu_has_feature(CPU_FTR_CTRL)) {
-		ctrl = mfspr(SPRN_CTRLF);
-		ctrl |= CTRL_RUNLATCH;
-		mtspr(SPRN_CTRLT, ctrl);
-	}
-}
-
-static inline void ppc64_runlatch_off(void)
-{
-	unsigned long ctrl;
-
-	if (cpu_has_feature(CPU_FTR_CTRL)) {
-		ctrl = mfspr(SPRN_CTRLF);
-		ctrl &= ~CTRL_RUNLATCH;
-		mtspr(SPRN_CTRLT, ctrl);
-	}
-}
+extern void ppc64_runlatch_on(void);
+extern void ppc64_runlatch_off(void);
 
 extern unsigned long scom970_read(unsigned int address);
 extern void scom970_write(unsigned int address, unsigned long value);
@@ -645,15 +627,6 @@
 #define __get_SP()	({unsigned long sp; \
 			asm volatile("mr %0,1": "=r" (sp)); sp;})
 
-#else /* __ASSEMBLY__ */
-
-#define RUNLATCH_ON(REG)			\
-BEGIN_FTR_SECTION				\
-	mfspr	(REG),SPRN_CTRLF;		\
-	ori	(REG),(REG),CTRL_RUNLATCH;	\
-	mtspr	SPRN_CTRLT,(REG);		\
-END_FTR_SECTION_IFSET(CPU_FTR_CTRL)
-
 #endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_REG_H */
diff --git a/include/asm-powerpc/thread_info.h b/include/asm-powerpc/thread_info.h
index c044ec1..237fc2b 100644
--- a/include/asm-powerpc/thread_info.h
+++ b/include/asm-powerpc/thread_info.h
@@ -113,7 +113,7 @@
 #define TIF_POLLING_NRFLAG	4	/* true if poll_idle() is polling
 					   TIF_NEED_RESCHED */
 #define TIF_32BIT		5	/* 32 bit binary */
-/* #define SPARE		6 */
+#define TIF_RUNLATCH		6	/* Is the runlatch enabled? */
 #define TIF_ABI_PENDING		7	/* 32/64 bit switch needed */
 #define TIF_SYSCALL_AUDIT	8	/* syscall auditing active */
 #define TIF_SINGLESTEP		9	/* singlestepping active */
@@ -131,7 +131,7 @@
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 #define _TIF_32BIT		(1<<TIF_32BIT)
-/* #define _SPARE		(1<<SPARE) */
+#define _TIF_RUNLATCH		(1<<TIF_RUNLATCH)
 #define _TIF_ABI_PENDING	(1<<TIF_ABI_PENDING)
 #define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
 #define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)