perf: arm_spe: Prevent overflow in PERF_IDX2OFF()

[ Upstream commit a29fea30dd93da16652930162b177941abd8c75e ]

Cast nr_pages to unsigned long to avoid overflow when handling large
AUX buffer sizes (>= 2 GiB).

Fixes: d5d9696 ("drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ulrich Hecht <uli@kernel.org>

Author: Leo-Yan

drivers/perf/arm_spe_pmu.c

@@ -85,7 +85,8 @@ struct arm_spe_pmu {
 #define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))
 
 /* Convert a free-running index from perf into an SPE buffer offset */
-#define PERF_IDX2OFF(idx, buf)	((idx) % ((buf)->nr_pages << PAGE_SHIFT))
+#define PERF_IDX2OFF(idx, buf) \
+	((idx) % ((unsigned long)(buf)->nr_pages << PAGE_SHIFT))
 
 /* Keep track of our dynamic hotplug state */
 static enum cpuhp_state arm_spe_pmu_online;