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Commit 00fcb147 authored by Kumar Gala's avatar Kumar Gala Committed by Benjamin Herrenschmidt
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powerpc/mm: Remove unused register usage in SW TLB miss handling 



Long ago we had some code that actually used the CTR in the SW TLB
miss handlers (603/e300).  Since we don't use it no reason to waste
cycles saving it off and restoring it (we actually didn't restore it
in the fast path case).

Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 4ae0ff60

arch/powerpc/kernel/head_32.S

+3 −8
Original line number Diff line number Diff line
@@ -475,12 +475,11 @@ SystemCall: 
	. = 0x1000

InstructionTLBMiss:

/*

 * r0:	stored ctr

 * r0:	scratch

 * r1:	linux style pte ( later becomes ppc hardware pte )

 * r2:	ptr to linux-style pte

 * r3:	scratch

 */

	mfctr	r0

	/* Get PTE (linux-style) and check access */

	mfspr	r3,SPRN_IMISS

	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
@@ -531,7 +530,6 @@ InstructionAddressInvalid: 


	addis	r1,r1,0x2000

	mtspr	SPRN_DSISR,r1	/* (shouldn't be needed) */

	mtctr	r0		/* Restore CTR */

	andi.	r2,r3,0xFFFF	/* Clear upper bits of SRR1 */

	or	r2,r2,r1

	mtspr	SPRN_SRR1,r2
@@ -552,12 +550,11 @@ InstructionAddressInvalid: 
	. = 0x1100

DataLoadTLBMiss:

/*

 * r0:	stored ctr

 * r0:	scratch

 * r1:	linux style pte ( later becomes ppc hardware pte )

 * r2:	ptr to linux-style pte

 * r3:	scratch

 */

	mfctr	r0

	/* Get PTE (linux-style) and check access */

	mfspr	r3,SPRN_DMISS

	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
@@ -607,7 +604,6 @@ DataAddressInvalid: 
	rlwinm	r1,r3,9,6,6	/* Get load/store bit */

	addis	r1,r1,0x2000

	mtspr	SPRN_DSISR,r1

	mtctr	r0		/* Restore CTR */

	andi.	r2,r3,0xFFFF	/* Clear upper bits of SRR1 */

	mtspr	SPRN_SRR1,r2

	mfspr	r1,SPRN_DMISS	/* Get failing address */
@@ -627,12 +623,11 @@ DataAddressInvalid: 
	. = 0x1200

DataStoreTLBMiss:

/*

 * r0:	stored ctr

 * r0:	scratch

 * r1:	linux style pte ( later becomes ppc hardware pte )

 * r2:	ptr to linux-style pte

 * r3:	scratch

 */

	mfctr	r0

	/* Get PTE (linux-style) and check access */

	mfspr	r3,SPRN_DMISS

	lis	r1,PAGE_OFFSET@h		/* check if kernel address */