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Commit 7c28f048 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
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powerpc/64s: Avoid saving faulting address into EX_DAR in SLB miss 



The EX_DAR save area is only used in exceptional cases. With r3 no
longer clobbered by slb_allocate_realmode, saving faulting address to
EX_DAR can be deferred to those cases.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent d59afffd

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

+8 −5
Original line number Diff line number Diff line
@@ -631,7 +631,6 @@ EXC_COMMON_BEGIN(slb_miss_realmode) 


	stw	r9,PACA_EXSLB+EX_CCR(r13)	/* save CR in exc. frame */

	std	r10,PACA_EXSLB+EX_LR(r13)	/* save LR */

	std	r3,PACA_EXSLB+EX_DAR(r13)



	crset	4*cr0+eq

#ifdef CONFIG_PPC_STD_MMU_64
@@ -641,11 +640,10 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) 
#endif



	ld	r10,PACA_EXSLB+EX_LR(r13)

	ld	r3,PACA_EXSLB+EX_R3(r13)

	lwz	r9,PACA_EXSLB+EX_CCR(r13)	/* get saved CR */

	mtlr	r10



	beq	8f		/* if bad address, make full stack frame */

	beq-	8f		/* if bad address, make full stack frame */



	andi.	r10,r12,MSR_RI	/* check for unrecoverable exception */

	beq-	2f
@@ -660,6 +658,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) 
.machine	pop



	RESTORE_PPR_PACA(PACA_EXSLB, r9)

	ld	r3,PACA_EXSLB+EX_R3(r13)

	ld	r9,PACA_EXSLB+EX_R9(r13)

	ld	r10,PACA_EXSLB+EX_R10(r13)

	ld	r11,PACA_EXSLB+EX_R11(r13)
@@ -668,7 +667,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) 
	rfid

	b	.	/* prevent speculative execution */



2:	mfspr	r11,SPRN_SRR0

2:	std     r3,PACA_EXSLB+EX_DAR(r13)

	ld	r3,PACA_EXSLB+EX_R3(r13)

	mfspr	r11,SPRN_SRR0

	LOAD_HANDLER(r10,unrecov_slb)

	mtspr	SPRN_SRR0,r10

	ld	r10,PACAKMSR(r13)
@@ -676,7 +677,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) 
	rfid

	b	.



8:	mfspr	r11,SPRN_SRR0

8:	std     r3,PACA_EXSLB+EX_DAR(r13)

	ld	r3,PACA_EXSLB+EX_R3(r13)

	mfspr	r11,SPRN_SRR0

	LOAD_HANDLER(r10,bad_addr_slb)

	mtspr	SPRN_SRR0,r10

	ld	r10,PACAKMSR(r13)