[PATCH] ppc64: Turn runlatch on in exception entry
Enable the runlatch at the start of each exception. Unfortunately we are out
of space in the 0x300 handler, so I added it a bit later.
The SPR write is fairly expensive, perhaps we should cache the runlatch state
in the paca and avoid the write when possible.
We don't need to turn the runlatch off, we do that in the idle loop. Better
to take the hit in the idle loop than for each exception exit.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/ppc64/kernel/head.S b/arch/ppc64/kernel/head.S
index 675c270..93ebcac0 100644
--- a/arch/ppc64/kernel/head.S
+++ b/arch/ppc64/kernel/head.S
@@ -308,6 +308,7 @@
label##_pSeries: \
HMT_MEDIUM; \
mtspr SPRG1,r13; /* save r13 */ \
+ RUNLATCH_ON(r13); \
EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common)
#define STD_EXCEPTION_ISERIES(n, label, area) \
@@ -315,6 +316,7 @@
label##_iSeries: \
HMT_MEDIUM; \
mtspr SPRG1,r13; /* save r13 */ \
+ RUNLATCH_ON(r13); \
EXCEPTION_PROLOG_ISERIES_1(area); \
EXCEPTION_PROLOG_ISERIES_2; \
b label##_common
@@ -324,6 +326,7 @@
label##_iSeries: \
HMT_MEDIUM; \
mtspr SPRG1,r13; /* save r13 */ \
+ RUNLATCH_ON(r13); \
EXCEPTION_PROLOG_ISERIES_1(PACA_EXGEN); \
lbz r10,PACAPROCENABLED(r13); \
cmpwi 0,r10,0; \
@@ -393,6 +396,7 @@
_machine_check_pSeries:
HMT_MEDIUM
mtspr SPRG1,r13 /* save r13 */
+ RUNLATCH_ON(r13)
EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
. = 0x300
@@ -419,6 +423,7 @@
data_access_slb_pSeries:
HMT_MEDIUM
mtspr SPRG1,r13
+ RUNLATCH_ON(r13)
mfspr r13,SPRG3 /* get paca address into r13 */
std r9,PACA_EXSLB+EX_R9(r13) /* save r9 - r12 */
std r10,PACA_EXSLB+EX_R10(r13)
@@ -439,6 +444,7 @@
instruction_access_slb_pSeries:
HMT_MEDIUM
mtspr SPRG1,r13
+ RUNLATCH_ON(r13)
mfspr r13,SPRG3 /* get paca address into r13 */
std r9,PACA_EXSLB+EX_R9(r13) /* save r9 - r12 */
std r10,PACA_EXSLB+EX_R10(r13)
@@ -464,6 +470,7 @@
.globl system_call_pSeries
system_call_pSeries:
HMT_MEDIUM
+ RUNLATCH_ON(r9)
mr r9,r13
mfmsr r10
mfspr r13,SPRG3
@@ -707,11 +714,13 @@
system_reset_fwnmi:
HMT_MEDIUM
mtspr SPRG1,r13 /* save r13 */
+ RUNLATCH_ON(r13)
EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common)
.globl machine_check_fwnmi
machine_check_fwnmi:
HMT_MEDIUM
mtspr SPRG1,r13 /* save r13 */
+ RUNLATCH_ON(r13)
EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common)
/*
@@ -848,6 +857,7 @@
.align 7
.globl data_access_common
data_access_common:
+ RUNLATCH_ON(r10) /* It wont fit in the 0x300 handler */
mfspr r10,DAR
std r10,PACA_EXGEN+EX_DAR(r13)
mfspr r10,DSISR
diff --git a/include/asm-ppc64/processor.h b/include/asm-ppc64/processor.h
index 06aa07c..352306c 100644
--- a/include/asm-ppc64/processor.h
+++ b/include/asm-ppc64/processor.h
@@ -524,6 +524,15 @@
#endif /* __ASSEMBLY__ */
+#ifdef __KERNEL__
+#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
+
/*
* Number of entries in the SLB. If this ever changes we should handle
* it with a use a cpu feature fixup.