Patchwork powerpc/perf: Fix handling of L3 events with bank == 1

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Submitter Michael Ellerman
Date March 13, 2014, 8:30 a.m.
Message ID <1394699434-31985-1-git-send-email-mpe@ellerman.id.au>
Download mbox | patch
Permalink /patch/329803/
State Accepted
Commit e9aaac1ac39f58a897e9b71e153317c8c216cb21
Delegated to: Michael Ellerman
Headers show

Comments

Michael Ellerman - March 13, 2014, 8:30 a.m.
Currently we reject events which have the L3 bank == 1, such as
0x000084918F, because the cache field is non-zero.

However that is incorrect, because although the bank is non-zero, the
value we would write into MMCRC is zero, and so we can count the event.

So fix the check to ignore the bank selector when checking whether the
cache selector is non-zero.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/perf/power8-pmu.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Patch

diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c
index 3ad363d..fe2763b 100644
--- a/arch/powerpc/perf/power8-pmu.c
+++ b/arch/powerpc/perf/power8-pmu.c
@@ -325,9 +325,10 @@  static int power8_get_constraint(u64 event, unsigned long *maskp, unsigned long
 		 * HV writable, and there is no API for guest kernels to modify
 		 * it. The solution is for the hypervisor to initialise the
 		 * field to zeroes, and for us to only ever allow events that
-		 * have a cache selector of zero.
+		 * have a cache selector of zero. The bank selector (bit 3) is
+		 * irrelevant, as long as the rest of the value is 0.
 		 */
-		if (cache)
+		if (cache & 0x7)
 			return -1;
 
 	} else if (event & EVENT_IS_L1) {