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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2012-03-02 11:33:52 +1100
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2012-03-09 10:55:20 +1100
commitd9ada91ae2969ae6b6dc3574fd08a6ebda5df766 (patch)
treea4509657892acb0b853760d6d26729a913a5fc2b /arch/powerpc
parent9424fabf8617c15e18a5ffd29bc3bcfa36620473 (diff)
downloadlinaro-lsk-d9ada91ae2969ae6b6dc3574fd08a6ebda5df766.tar.gz
powerpc: Replace mfmsr instructions with load from PACA kernel_msr field
On 64-bit, the mfmsr instruction can be quite slow, slower than loading a field from the cache-hot PACA, which happens to already contain the value we want in most cases. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/exception-64s.h2
-rw-r--r--arch/powerpc/include/asm/hw_irq.h4
-rw-r--r--arch/powerpc/kernel/entry_64.S14
-rw-r--r--arch/powerpc/kernel/exceptions-64s.S5
4 files changed, 10 insertions, 15 deletions
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 7f4718c4f04..70354af0740 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -298,7 +298,7 @@ label##_hv: \
/* Exception addition: Keep interrupt state */
#define ENABLE_INTS \
- mfmsr r11; \
+ ld r11,PACAKMSR(r13); \
ld r12,_MSR(r1); \
rlwimi r11,r12,0,MSR_EE; \
mtmsrd r11,1
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 531ba00fcba..6c6fa955baa 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -68,8 +68,8 @@ static inline bool arch_irqs_disabled(void)
#define __hard_irq_enable() asm volatile("wrteei 1" : : : "memory");
#define __hard_irq_disable() asm volatile("wrteei 0" : : : "memory");
#else
-#define __hard_irq_enable() __mtmsrd(mfmsr() | MSR_EE, 1)
-#define __hard_irq_disable() __mtmsrd(mfmsr() & ~MSR_EE, 1)
+#define __hard_irq_enable() __mtmsrd(local_paca->kernel_msr | MSR_EE, 1)
+#define __hard_irq_disable() __mtmsrd(local_paca->kernel_msr, 1)
#endif
#define hard_irq_disable() \
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index cc030b73174..c513beb78b3 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -557,10 +557,8 @@ _GLOBAL(ret_from_except_lite)
#ifdef CONFIG_PPC_BOOK3E
wrteei 0
#else
- mfmsr r10 /* Get current interrupt state */
- rldicl r9,r10,48,1 /* clear MSR_EE */
- rotldi r9,r9,16
- mtmsrd r9,1 /* Update machine state */
+ ld r10,PACAKMSR(r13) /* Get kernel MSR without EE */
+ mtmsrd r10,1 /* Update machine state */
#endif /* CONFIG_PPC_BOOK3E */
#ifdef CONFIG_PREEMPT
@@ -625,8 +623,8 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
* userspace and we take an exception after restoring r13,
* we end up corrupting the userspace r13 value.
*/
- mfmsr r4
- andc r4,r4,r0 /* r0 contains MSR_RI here */
+ ld r4,PACAKMSR(r13) /* Get kernel MSR without EE */
+ andc r4,r4,r0 /* r0 contains MSR_RI here */
mtmsrd r4,1
/*
@@ -686,9 +684,7 @@ do_work:
#ifdef CONFIG_PPC_BOOK3E
wrteei 0
#else
- mfmsr r10
- rldicl r10,r10,48,1
- rotldi r10,r10,16
+ ld r10,PACAKMSR(r13) /* Get kernel MSR without EE */
mtmsrd r10,1
#endif /* CONFIG_PPC_BOOK3E */
li r0,0
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 0fb42ae2169..02448ea58ad 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -848,9 +848,8 @@ fast_exception_return:
REST_GPR(0, r1)
REST_8GPRS(2, r1)
- mfmsr r10
- rldicl r10,r10,48,1 /* clear EE */
- rldicr r10,r10,16,61 /* clear RI (LE is 0 already) */
+ ld r10,PACAKMSR(r13)
+ clrrdi r10,r10,2 /* clear RI */
mtmsrd r10,1
mtspr SPRN_SRR1,r12