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Commit a53b27b3 authored by Michael Ellerman's avatar Michael Ellerman Committed by Benjamin Herrenschmidt
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powerpc/perf: Fix handling of FAB events 



Commit 4df48999 "Add power8 EBB support" included a bug in the handling
of the FAB_CRESP_MATCH and FAB_TYPE_MATCH fields.

These values are pulled out of the event code using EVENT_THR_CTL_SHIFT,
however we were then or'ing that value directly into MMCR1.

This meant we were failing to set the FAB fields correctly, and also
potentially corrupting the value for PMC4SEL. Leading to no counts for
the FAB events and incorrect counts for PMC4.

The fix is simply to shift left the FAB value correctly before or'ing it
with MMCR1.

Reported-by: default avatarSooraj Ravindran Nair <soonair3@in.ibm.com>
Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent e82b89a6

arch/powerpc/perf/power8-pmu.c

+3 −2
Original line number Diff line number Diff line
@@ -199,6 +199,7 @@ 
#define MMCR1_UNIT_SHIFT(pmc)		(60 - (4 * ((pmc) - 1)))

#define MMCR1_COMBINE_SHIFT(pmc)	(35 - ((pmc) - 1))

#define MMCR1_PMCSEL_SHIFT(pmc)		(24 - (((pmc) - 1)) * 8)

#define MMCR1_FAB_SHIFT			36

#define MMCR1_DC_QUAL_SHIFT		47

#define MMCR1_IC_QUAL_SHIFT		46
@@ -388,8 +389,8 @@ static int power8_compute_mmcr(u64 event[], int n_ev, 
		 * the threshold bits are used for the match value.

		 */

		if (event_is_fab_match(event[i])) {

			mmcr1 |= (event[i] >> EVENT_THR_CTL_SHIFT) &

				  EVENT_THR_CTL_MASK;

			mmcr1 |= ((event[i] >> EVENT_THR_CTL_SHIFT) &

				  EVENT_THR_CTL_MASK) << MMCR1_FAB_SHIFT;

		} else {

			val = (event[i] >> EVENT_THR_CTL_SHIFT) & EVENT_THR_CTL_MASK;

			mmcra |= val << MMCRA_THR_CTL_SHIFT;