Commit d2e00603 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/32: Use SPRN_SPRG_SCRATCH2 in exception prologs 



Use SPRN_SPRG_SCRATCH2 as a third scratch register in
exception prologs in order to simplify them and avoid
data going back and forth from/to CR.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6f5c8a7faa8cc54acb89c55c20aa579a2f30a4e9.1606285014.git.christophe.leroy@csgroup.eu
parent de1cd079

arch/powerpc/kernel/head_32.h

+7 −15
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ 


.macro EXCEPTION_PROLOG_1 for_rtas=0

#ifdef CONFIG_VMAP_STACK

	mr	r11, r1

	mtspr	SPRN_SPRG_SCRATCH2,r1

	subi	r1, r1, INT_FRAME_SIZE		/* use r1 if kernel */

	beq	1f

	mfspr	r1,SPRN_SPRG_THREAD
@@ -61,15 +61,10 @@ 


.macro EXCEPTION_PROLOG_2 handle_dar_dsisr=0

#ifdef CONFIG_VMAP_STACK

	mtcr	r10

	li	r10, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */

	mtmsr	r10

	li	r11, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */

	mtmsr	r11

	isync

#else

	stw	r10,_CCR(r11)		/* save registers */

#endif

	mfspr	r10, SPRN_SPRG_SCRATCH0

#ifdef CONFIG_VMAP_STACK

	mfspr	r11, SPRN_SPRG_SCRATCH2

	stw	r11,GPR1(r1)

	stw	r11,0(r1)

	mr	r11, r1
@@ -78,14 +73,12 @@ 
	stw	r1,0(r11)

	tovirt(r1, r11)		/* set new kernel sp */

#endif

	stw	r10,_CCR(r11)		/* save registers */

	stw	r12,GPR12(r11)

	stw	r9,GPR9(r11)

	stw	r10,GPR10(r11)

#ifdef CONFIG_VMAP_STACK

	mfcr	r10

	stw	r10, _CCR(r11)

#endif

	mfspr	r10,SPRN_SPRG_SCRATCH0

	mfspr	r12,SPRN_SPRG_SCRATCH1

	stw	r10,GPR10(r11)

	stw	r12,GPR11(r11)

	mflr	r10

	stw	r10,_LINK(r11)
@@ -99,7 +92,6 @@ 
	stw	r10, _DSISR(r11)

	.endif

	lwz	r9, SRR1(r12)

	andi.	r10, r9, MSR_PR

	lwz	r12, SRR0(r12)

#else

	mfspr	r12,SPRN_SRR0