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Commit d9ada91a authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 9424fabf

arch/powerpc/include/asm/exception-64s.h

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/powerpc/include/asm/hw_irq.h

+2 −2
Original line number Diff line number Diff line
@@ -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()			\

arch/powerpc/kernel/entry_64.S

+5 −9
Original line number Diff line number Diff line
@@ -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
@@ -625,7 +623,7 @@ 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

	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

arch/powerpc/kernel/exceptions-64s.S

+2 −3
Original line number Diff line number Diff line
@@ -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