Re: [PATCH V2] drivers: CCI: fix used_mask init in validate_group()

From: Suzuki K. Poulose
Date: Wed Apr 15 2015 - 08:50:33 EST


On 15/04/15 12:58, Will Deacon wrote:
On Wed, Apr 15, 2015 at 11:44:06AM +0100, Suzuki K. Poulose wrote:
On 09/04/15 15:57, Mark Salter wrote:
Currently in validate_group(), there is a static initializer
for fake_pmu.used_mask which is based on CPU_BITS_NONE but
the used_mask array size is based on CCI_PMU_MAX_HW_EVENTS.
CCI_PMU_MAX_HW_EVENTS is not based on NR_CPUS, so CPU_BITS_NONE
is not correct and will cause a build failure if NR_CPUS
is set high enough to make CPU_BITS_NONE larger than used_mask.

Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
---
drivers/bus/arm-cci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 84fd660..759e41c 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -684,7 +684,7 @@ validate_group(struct perf_event *event)
* Initialise the fake PMU. We only need to populate the
* used_mask for the purposes of validation.
*/
- .used_mask = CPU_BITS_NONE,
+ .used_mask = { 0 },
};

if (!validate_event(&fake_pmu, leader))

I have a series of patches to add CCI-500 PMU, targeting 4.2, which
changes the used_mask to a pointer and changes it to depend on the
number of counters available on the CCI PMU. I will post it in very
soon here, which could make this patch obsolete. Let me know if you
don't mind getting this sorted out through my series. I am fine either way.

I'd rather have the fix in for 4.1 and then have your CCI-500 patches based
on that.

Will

OK, will rebase my patches on top of this one.

Thanks
Suzuki

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