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Commit c7305645 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
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powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL 



In the SLB miss handler we may be returning to user or kernel. We need
to add a check early on and save the result in the cr4 register, and
then we bifurcate the return path based on that.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent a08f828c

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

+28 −1
Original line number Diff line number Diff line
@@ -598,6 +598,9 @@ EXC_COMMON_BEGIN(slb_miss_common) 
	stw	r9,PACA_EXSLB+EX_CCR(r13)	/* save CR in exc. frame */

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



	andi.	r9,r11,MSR_PR	// Check for exception from userspace

	cmpdi	cr4,r9,MSR_PR	// And save the result in CR4 for later



	/*

	 * Test MSR_RI before calling slb_allocate_realmode, because the

	 * MSR in r11 gets clobbered. However we still want to allocate
@@ -624,9 +627,32 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) 


	/* All done -- return from exception. */



	bne	cr4,1f		/* returning to kernel */



.machine	push

.machine	"power4"

	mtcrf	0x80,r9

	mtcrf	0x08,r9		/* MSR[PR] indication is in cr4 */

	mtcrf	0x04,r9		/* MSR[RI] indication is in cr5 */

	mtcrf	0x02,r9		/* I/D indication is in cr6 */

	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */

.machine	pop



	RESTORE_CTR(r9, PACA_EXSLB)

	RESTORE_PPR_PACA(PACA_EXSLB, r9)

	mr	r3,r12

	ld	r9,PACA_EXSLB+EX_R9(r13)

	ld	r10,PACA_EXSLB+EX_R10(r13)

	ld	r11,PACA_EXSLB+EX_R11(r13)

	ld	r12,PACA_EXSLB+EX_R12(r13)

	ld	r13,PACA_EXSLB+EX_R13(r13)

	RFI_TO_USER

	b	.	/* prevent speculative execution */

1:

.machine	push

.machine	"power4"

	mtcrf	0x80,r9

	mtcrf	0x08,r9		/* MSR[PR] indication is in cr4 */

	mtcrf	0x04,r9		/* MSR[RI] indication is in cr5 */

	mtcrf	0x02,r9		/* I/D indication is in cr6 */

	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */
@@ -640,9 +666,10 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX) 
	ld	r11,PACA_EXSLB+EX_R11(r13)

	ld	r12,PACA_EXSLB+EX_R12(r13)

	ld	r13,PACA_EXSLB+EX_R13(r13)

	rfid

	RFI_TO_KERNEL

	b	.	/* prevent speculative execution */





2:	std     r3,PACA_EXSLB+EX_DAR(r13)

	mr	r3,r12

	mfspr	r11,SPRN_SRR0