Commit 7cbba630 authored by Michael Ellerman's avatar Michael Ellerman Committed by Benjamin Herrenschmidt
Browse files

powerpc/perf: Avoid mutating event in power8_get_constraint() 



We only need to mask the EBB bit out of the event for the check of the
special PMC 5 & 6 events. So use a local to do it just for that code,
rather than changing the event value for the life of the function.

While we're there move the set of mask and value after all the checks.

Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent fb568d76

arch/powerpc/perf/power8-pmu.c

+8 −6
Original line number Diff line number Diff line
@@ -270,18 +270,20 @@ static int power8_get_constraint(u64 event, unsigned long *maskp, unsigned long 
	cache = (event >> EVENT_CACHE_SEL_SHIFT)  & EVENT_CACHE_SEL_MASK;

	ebb   = (event >> EVENT_EBB_SHIFT)        & EVENT_EBB_MASK;



	/* Clear the EBB bit in the event, so event checks work below */

	event &= ~(EVENT_EBB_MASK << EVENT_EBB_SHIFT);



	if (pmc) {

		u64 base_event;



		if (pmc > 6)

			return -1;



		mask  |= CNST_PMC_MASK(pmc);

		value |= CNST_PMC_VAL(pmc);

		/* Ignore Linux defined bits when checking event below */

		base_event = event & ~(EVENT_EBB_MASK << EVENT_EBB_SHIFT);



		if (pmc >= 5 && event != 0x500fa && event != 0x600f4)

		if (pmc >= 5 && base_event != 0x500fa && base_event != 0x600f4)

			return -1;



		mask  |= CNST_PMC_MASK(pmc);

		value |= CNST_PMC_VAL(pmc);

	}



	if (pmc <= 4) {