[PATCH 11/12] powerpc: Replace mfmsr instructions with load from PACA kernel_msr field
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STALE5337d
SUPERSEDED
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2012-03-02 09:36:17
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Revision v1 of 2 in this series.
Revisions (2)
- v1 current
- v2 [diff vs current]
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> --- arch/powerpc/include/asm/exception-64s.h | 2 +- arch/powerpc/include/asm/hw_irq.h | 4 ++-- arch/powerpc/kernel/entry_64.S | 14 +++++--------- arch/powerpc/kernel/exceptions-64s.S | 5 ++--- 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 7f4718c..70354af 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 531ba00..6c6fa95 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 cc030b7..c513beb 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 bd7130c..880f360 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S@@ -850,9 +850,8 @@ 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
--
1.7.9