[PATCH v1 1/1] perf/smmuv3: Don't cast parameter in bit operations

From: Andy Shevchenko
Date: Wed Feb 09 2022 - 13:53:03 EST


While in this particular case it would not be a (critical) issue,
the pattern itself is bad and error prone in case somebody blindly
copies to their code.

Don't cast parameter to unsigned long pointer in the bit operations.
Instead copy to a local variable on stack of a proper type and use.

Note, new compilers might warn on this line for potential outbound access.

Fixes: 7d839b4b9e00 ("perf/smmuv3: Add arm64 smmuv3 pmu driver")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/perf/arm_smmuv3_pmu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
index c49108a72865..00d4c45a8017 100644
--- a/drivers/perf/arm_smmuv3_pmu.c
+++ b/drivers/perf/arm_smmuv3_pmu.c
@@ -654,6 +654,7 @@ static int smmu_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
static irqreturn_t smmu_pmu_handle_irq(int irq_num, void *data)
{
struct smmu_pmu *smmu_pmu = data;
+ DECLARE_BITMAP(ovs, BITS_PER_TYPE(u64));
u64 ovsr;
unsigned int idx;

@@ -663,7 +664,8 @@ static irqreturn_t smmu_pmu_handle_irq(int irq_num, void *data)

writeq(ovsr, smmu_pmu->reloc_base + SMMU_PMCG_OVSCLR0);

- for_each_set_bit(idx, (unsigned long *)&ovsr, smmu_pmu->num_counters) {
+ bitmap_from_u64(ovs, ovsr);
+ for_each_set_bit(idx, ovs, smmu_pmu->num_counters) {
struct perf_event *event = smmu_pmu->events[idx];
struct hw_perf_event *hwc;

--
2.34.1