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Commit 8cfe4f52 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/8xx: Move SW perf counters in first 32kb of memory 



In order to simplify time critical exceptions handling 8xx
specific SW perf counters, this patch moves the counters into
the beginning of memory. This is possible because .text is readable
and the counters are never modified outside of the handlers.

By doing this, we avoid having to set a second register with
the upper part of the address of the counters.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 32bff4b9

arch/powerpc/kernel/head_8xx.S

+28 −30
Original line number Diff line number Diff line
@@ -106,6 +106,23 @@ turn_on_mmu: 
	mtspr	SPRN_SRR0,r0

	rfi				/* enables MMU */





#ifdef CONFIG_PERF_EVENTS

	.align	4



	.globl	itlb_miss_counter

itlb_miss_counter:

	.space	4



	.globl	dtlb_miss_counter

dtlb_miss_counter:

	.space	4



	.globl	instruction_counter

instruction_counter:

	.space	4

#endif



/*

 * Exception entry code.  This code runs with address translation

 * turned off, i.e. using physical addresses.
@@ -384,17 +401,16 @@ InstructionTLBMiss: 


#ifdef CONFIG_PERF_EVENTS

	patch_site	0f, patch__itlbmiss_perf

0:	lis	r10, (itlb_miss_counter - PAGE_OFFSET)@ha

	lwz	r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10)

	addi	r11, r11, 1

	stw	r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10)

#endif

0:	lwz	r10, (itlb_miss_counter - PAGE_OFFSET)@l(0)

	addi	r10, r10, 1

	stw	r10, (itlb_miss_counter - PAGE_OFFSET)@l(0)

	mfspr	r10, SPRN_SPRG_SCRATCH0

	mfspr	r11, SPRN_SPRG_SCRATCH1

#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE)

	mfspr	r12, SPRN_SPRG_SCRATCH2

#endif

	rfi

#endif



#ifdef CONFIG_HUGETLB_PAGE

10:	/* 8M pages */
@@ -509,15 +525,14 @@ DataStoreTLBMiss: 


#ifdef CONFIG_PERF_EVENTS

	patch_site	0f, patch__dtlbmiss_perf

0:	lis	r10, (dtlb_miss_counter - PAGE_OFFSET)@ha

	lwz	r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10)

	addi	r11, r11, 1

	stw	r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10)

#endif

0:	lwz	r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0)

	addi	r10, r10, 1

	stw	r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0)

	mfspr	r10, SPRN_SPRG_SCRATCH0

	mfspr	r11, SPRN_SPRG_SCRATCH1

	mfspr	r12, SPRN_SPRG_SCRATCH2

	rfi

#endif



#ifdef CONFIG_HUGETLB_PAGE

10:	/* 8M pages */
@@ -625,16 +640,13 @@ DataBreakpoint: 
	. = 0x1d00

InstructionBreakpoint:

	mtspr	SPRN_SPRG_SCRATCH0, r10

	mtspr	SPRN_SPRG_SCRATCH1, r11

	lis	r10, (instruction_counter - PAGE_OFFSET)@ha

	lwz	r11, (instruction_counter - PAGE_OFFSET)@l(r10)

	addi	r11, r11, -1

	stw	r11, (instruction_counter - PAGE_OFFSET)@l(r10)

	lwz	r10, (instruction_counter - PAGE_OFFSET)@l(0)

	addi	r10, r10, -1

	stw	r10, (instruction_counter - PAGE_OFFSET)@l(0)

	lis	r10, 0xffff

	ori	r10, r10, 0x01

	mtspr	SPRN_COUNTA, r10

	mfspr	r10, SPRN_SPRG_SCRATCH0

	mfspr	r11, SPRN_SPRG_SCRATCH1

	rfi

#else

	EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_EE)
@@ -1065,17 +1077,3 @@ swapper_pg_dir: 
 */

abatron_pteptrs:

	.space	8
 


#ifdef CONFIG_PERF_EVENTS

	.globl	itlb_miss_counter

itlb_miss_counter:

	.space	4



	.globl	dtlb_miss_counter

dtlb_miss_counter:

	.space	4



	.globl	instruction_counter

instruction_counter:

	.space	4

#endif