2 files changed, 34 insertions, 10 deletions

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 2b03a09fe5e9..bb845eed0e98 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -319,7 +319,6 @@ exception_marker:
 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##_pSeries:					\
 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:					\
 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:						\
 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 @@ __start_interrupts:
 _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 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SLB)
 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 @@ data_access_slb_pSeries:
 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 @@ instruction_access_slb_pSeries:
         .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 @@ slb_miss_user_pseries:
 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 @@ system_reset_fwnmi:
 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 @@ unrecov_fer:
         .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 @@ hardware_interrupt_common:
         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 57703994a063..c225cf154bfe 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -888,3 +888,35 @@ void dump_stack(void)
         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