1 files changed, 57 insertions, 0 deletions
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 5c00e0164c..1dc267de46 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1009,6 +1009,63 @@ static inline uint64_t pmu_counter_mask(CPUARMState *env)
   return (1 << 31) | ((1 << pmu_num_counters(env)) - 1);
 }
 
+typedef struct pm_event {
+    uint16_t number; /* PMEVTYPER.evtCount is 16 bits wide */
+    /* If the event is supported on this CPU (used to generate PMCEID[01]) */
+    bool (*supported)(CPUARMState *);
+    /*
+     * Retrieve the current count of the underlying event. The programmed
+     * counters hold a difference from the return value from this function
+     */
+    uint64_t (*get_count)(CPUARMState *);
+} pm_event;
+
+static const pm_event pm_events[] = {
+};
+
+/*
+ * Note: Before increasing MAX_EVENT_ID beyond 0x3f into the 0x40xx range of
+ * events (i.e. the statistical profiling extension), this implementation
+ * should first be updated to something sparse instead of the current
+ * supported_event_map[] array.
+ */
+#define MAX_EVENT_ID 0x0
+#define UNSUPPORTED_EVENT UINT16_MAX
+static uint16_t supported_event_map[MAX_EVENT_ID + 1];
+
+/*
+ * Called upon initialization to build PMCEID0_EL0 or PMCEID1_EL0 (indicated by
+ * 'which'). We also use it to build a map of ARM event numbers to indices in
+ * our pm_events array.
+ *
+ * Note: Events in the 0x40XX range are not currently supported.
+ */
+uint64_t get_pmceid(CPUARMState *env, unsigned which)
+{
+    uint64_t pmceid = 0;
+    unsigned int i;
+
+    assert(which <= 1);
+
+    for (i = 0; i < ARRAY_SIZE(supported_event_map); i++) {
+        supported_event_map[i] = UNSUPPORTED_EVENT;
+    }
+
+    for (i = 0; i < ARRAY_SIZE(pm_events); i++) {
+        const pm_event *cnt = &pm_events[i];
+        assert(cnt->number <= MAX_EVENT_ID);
+        /* We do not currently support events in the 0x40xx range */
+        assert(cnt->number <= 0x3f);
+
+        if ((cnt->number & 0x20) == (which << 6) &&
+                cnt->supported(env)) {
+            pmceid |= (1 << (cnt->number & 0x1f));
+            supported_event_map[cnt->number] = i;
+        }
+    }
+    return pmceid;
+}
+
 static CPAccessResult pmreg_access(CPUARMState *env, const ARMCPRegInfo *ri,
                                    bool isread)
 {