1 files changed, 21 insertions, 19 deletions

diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
index 2ce24e74f879..8aec462d90fb 100644
--- a/arch/arc/kernel/perf_event.c
+++ b/arch/arc/kernel/perf_event.c
@@ -336,15 +336,12 @@ static int arc_pmu_add(struct perf_event *event, int flags)
         struct hw_perf_event *hwc = &event->hw;
         int idx = hwc->idx;
 
-        if (__test_and_set_bit(idx, pmu_cpu->used_mask)) {
-                idx = find_first_zero_bit(pmu_cpu->used_mask,
-                                          arc_pmu->n_counters);
-                if (idx == arc_pmu->n_counters)
-                        return -EAGAIN;
-
-                __set_bit(idx, pmu_cpu->used_mask);
-                hwc->idx = idx;
-        }
+        idx = ffz(pmu_cpu->used_mask[0]);
+        if (idx == arc_pmu->n_counters)
+                return -EAGAIN;
+
+        __set_bit(idx, pmu_cpu->used_mask);
+        hwc->idx = idx;
 
         write_aux_reg(ARC_REG_PCT_INDEX, idx);
 
@@ -377,21 +374,22 @@ static irqreturn_t arc_pmu_intr(int irq, void *dev)
         struct perf_sample_data data;
         struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu);
         struct pt_regs *regs;
-        int active_ints;
+        unsigned int active_ints;
         int idx;
 
         arc_pmu_disable(&arc_pmu->pmu);
 
         active_ints = read_aux_reg(ARC_REG_PCT_INT_ACT);
+        if (!active_ints)
+                goto done;
 
         regs = get_irq_regs();
 
-        for (idx = 0; idx < arc_pmu->n_counters; idx++) {
-                struct perf_event *event = pmu_cpu->act_counter[idx];
+        do {
+                struct perf_event *event;
                 struct hw_perf_event *hwc;
 
-                if (!(active_ints & (1 << idx)))
-                        continue;
+                idx = __ffs(active_ints);
 
                 /* Reset interrupt flag by writing of 1 */
                 write_aux_reg(ARC_REG_PCT_INT_ACT, 1 << idx);
@@ -404,19 +402,22 @@ static irqreturn_t arc_pmu_intr(int irq, void *dev)
                 write_aux_reg(ARC_REG_PCT_INT_CTRL,
                         read_aux_reg(ARC_REG_PCT_INT_CTRL) | (1 << idx));
 
+                event = pmu_cpu->act_counter[idx];
                 hwc = &event->hw;
 
                 WARN_ON_ONCE(hwc->idx != idx);
 
                 arc_perf_event_update(event, &event->hw, event->hw.idx);
                 perf_sample_data_init(&data, 0, hwc->last_period);
-                if (!arc_pmu_event_set_period(event))
-                        continue;
+                if (arc_pmu_event_set_period(event)) {
+                        if (perf_event_overflow(event, &data, regs))
+                                arc_pmu_stop(event, 0);
+                }
 
-                if (perf_event_overflow(event, &data, regs))
-                        arc_pmu_stop(event, 0);
-        }
+                active_ints &= ~(1U << idx);
+        } while (active_ints);
 
+done:
         arc_pmu_enable(&arc_pmu->pmu);
 
         return IRQ_HANDLED;
@@ -461,6 +462,7 @@ static int arc_pmu_device_probe(struct platform_device *pdev)
                 pr_err("This core does not have performance counters!\n");
                 return -ENODEV;
         }
+        BUILD_BUG_ON(ARC_PERF_MAX_COUNTERS > 32);
         BUG_ON(pct_bcr.c > ARC_PERF_MAX_COUNTERS);
 
         READ_BCR(ARC_REG_CC_BUILD, cc_bcr);