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Commit 090b9284 authored by Michael Neuling's avatar Michael Neuling Committed by Benjamin Herrenschmidt
Browse files

powerpc/tm: Clear MSR RI in non-recoverable TM code 



When we treclaim and trecheckpoint there's an unavoidable period when r1
will not be a valid kernel stack pointer.

This patch clears the MSR recoverable interrupt (RI) bit over these
regions to indicate we have an invalid kernel stack pointer.

For treclaim, the region over which we clear MSR RI is larger than
required to avoid the need for an extra costly mtmsrd.

Thanks to Paulus for suggesting this change.

Signed-off-by: default avatarMichael Neuling <mikey@neuling.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 80aa0fb4

arch/powerpc/kernel/tm.S

+16 −2
Original line number Diff line number Diff line
@@ -112,9 +112,18 @@ _GLOBAL(tm_reclaim) 
	std	r3, STACK_PARAM(0)(r1)

	SAVE_NVGPRS(r1)



	/* We need to setup MSR for VSX register save instructions.  Here we

	 * also clear the MSR RI since when we do the treclaim, we won't have a

	 * valid kernel pointer for a while.  We clear RI here as it avoids

	 * adding another mtmsr closer to the treclaim.  This makes the region

	 * maked as non-recoverable wider than it needs to be but it saves on

	 * inserting another mtmsrd later.

	 */

	mfmsr	r14

	mr	r15, r14

	ori	r15, r15, MSR_FP

	li	r16, MSR_RI

	andc	r15, r15, r16

	oris	r15, r15, MSR_VEC@h

#ifdef CONFIG_VSX

	BEGIN_FTR_SECTION
@@ -349,9 +358,10 @@ restore_gprs: 
	mtcr	r5

	mtxer	r6



	/* MSR and flags:  We don't change CRs, and we don't need to alter

	 * MSR.

	/* Clear the MSR RI since we are about to change R1.  EE is already off

	 */

	li	r4, 0

	mtmsrd	r4, 1



	REST_4GPRS(0, r7)			/* GPR0-3 */

	REST_GPR(4, r7)				/* GPR4-6 */
@@ -377,6 +387,10 @@ restore_gprs: 
	GET_PACA(r13)

	GET_SCRATCH0(r1)



	/* R1 is restored, so we are recoverable again.  EE is still off */

	li	r4, MSR_RI

	mtmsrd	r4, 1



	REST_NVGPRS(r1)



	addi    r1, r1, TM_FRAME_SIZE