1 files changed, 164 insertions, 2 deletions

diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c
index 527c8b98e97e..9f9dfda9ed2c 100644
--- a/arch/powerpc/perf/hv-24x7.c
+++ b/arch/powerpc/perf/hv-24x7.c
@@ -142,6 +142,15 @@ static struct attribute_group event_long_desc_group = {
 
 static struct kmem_cache *hv_page_cache;
 
+DEFINE_PER_CPU(int, hv_24x7_txn_flags);
+DEFINE_PER_CPU(int, hv_24x7_txn_err);
+
+struct hv_24x7_hw {
+	struct perf_event *events[255];
+};
+
+DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw);
+
 /*
  * request_buffer and result_buffer are not required to be 4k aligned,
  * but are not allowed to cross any 4k boundary. Aligning them to 4k is
@@ -1231,9 +1240,48 @@ static void update_event_count(struct perf_event *event, u64 now)
 static void h_24x7_event_read(struct perf_event *event)
 {
 	u64 now;
+	struct hv_24x7_request_buffer *request_buffer;
+	struct hv_24x7_hw *h24x7hw;
+	int txn_flags;
+
+	txn_flags = __this_cpu_read(hv_24x7_txn_flags);
+
+	/*
+	 * If in a READ transaction, add this counter to the list of
+	 * counters to read during the next HCALL (i.e commit_txn()).
+	 * If not in a READ transaction, go ahead and make the HCALL
+	 * to read this counter by itself.
+	 */
+
+	if (txn_flags & PERF_PMU_TXN_READ) {
+		int i;
+		int ret;
 
-	now = h_24x7_get_value(event);
-	update_event_count(event, now);
+		if (__this_cpu_read(hv_24x7_txn_err))
+			return;
+
+		request_buffer = (void *)get_cpu_var(hv_24x7_reqb);
+
+		ret = add_event_to_24x7_request(event, request_buffer);
+		if (ret) {
+			__this_cpu_write(hv_24x7_txn_err, ret);
+		} else {
+			/*
+			 * Assoicate the event with the HCALL request index,
+			 * so ->commit_txn() can quickly find/update count.
+			 */
+			i = request_buffer->num_requests - 1;
+
+			h24x7hw = &get_cpu_var(hv_24x7_hw);
+			h24x7hw->events[i] = event;
+			put_cpu_var(h24x7hw);
+		}
+
+		put_cpu_var(hv_24x7_reqb);
+	} else {
+		now = h_24x7_get_value(event);
+		update_event_count(event, now);
+	}
 }
 
 static void h_24x7_event_start(struct perf_event *event, int flags)
@@ -1255,6 +1303,117 @@ static int h_24x7_event_add(struct perf_event *event, int flags)
 	return 0;
 }
 
+/*
+ * 24x7 counters only support READ transactions. They are
+ * always counting and dont need/support ADD transactions.
+ * Cache the flags, but otherwise ignore transactions that
+ * are not PERF_PMU_TXN_READ.
+ */
+static void h_24x7_event_start_txn(struct pmu *pmu, unsigned int flags)
+{
+	struct hv_24x7_request_buffer *request_buffer;
+	struct hv_24x7_data_result_buffer *result_buffer;
+
+	/* We should not be called if we are already in a txn */
+	WARN_ON_ONCE(__this_cpu_read(hv_24x7_txn_flags));
+
+	__this_cpu_write(hv_24x7_txn_flags, flags);
+	if (flags & ~PERF_PMU_TXN_READ)
+		return;
+
+	request_buffer = (void *)get_cpu_var(hv_24x7_reqb);
+	result_buffer = (void *)get_cpu_var(hv_24x7_resb);
+
+	init_24x7_request(request_buffer, result_buffer);
+
+	put_cpu_var(hv_24x7_resb);
+	put_cpu_var(hv_24x7_reqb);
+}
+
+/*
+ * Clean up transaction state.
+ *
+ * NOTE: Ignore state of request and result buffers for now.
+ *	 We will initialize them during the next read/txn.
+ */
+static void reset_txn(void)
+{
+	__this_cpu_write(hv_24x7_txn_flags, 0);
+	__this_cpu_write(hv_24x7_txn_err, 0);
+}
+
+/*
+ * 24x7 counters only support READ transactions. They are always counting
+ * and dont need/support ADD transactions. Clear ->txn_flags but otherwise
+ * ignore transactions that are not of type PERF_PMU_TXN_READ.
+ *
+ * For READ transactions, submit all pending 24x7 requests (i.e requests
+ * that were queued by h_24x7_event_read()), to the hypervisor and update
+ * the event counts.
+ */
+static int h_24x7_event_commit_txn(struct pmu *pmu)
+{
+	struct hv_24x7_request_buffer *request_buffer;
+	struct hv_24x7_data_result_buffer *result_buffer;
+	struct hv_24x7_result *resb;
+	struct perf_event *event;
+	u64 count;
+	int i, ret, txn_flags;
+	struct hv_24x7_hw *h24x7hw;
+
+	txn_flags = __this_cpu_read(hv_24x7_txn_flags);
+	WARN_ON_ONCE(!txn_flags);
+
+	ret = 0;
+	if (txn_flags & ~PERF_PMU_TXN_READ)
+		goto out;
+
+	ret = __this_cpu_read(hv_24x7_txn_err);
+	if (ret)
+		goto out;
+
+	request_buffer = (void *)get_cpu_var(hv_24x7_reqb);
+	result_buffer = (void *)get_cpu_var(hv_24x7_resb);
+
+	ret = make_24x7_request(request_buffer, result_buffer);
+	if (ret) {
+		log_24x7_hcall(request_buffer, result_buffer, ret);
+		goto put_reqb;
+	}
+
+	h24x7hw = &get_cpu_var(hv_24x7_hw);
+
+	/* Update event counts from hcall */
+	for (i = 0; i < request_buffer->num_requests; i++) {
+		resb = &result_buffer->results[i];
+		count = be64_to_cpu(resb->elements[0].element_data[0]);
+		event = h24x7hw->events[i];
+		h24x7hw->events[i] = NULL;
+		update_event_count(event, count);
+	}
+
+	put_cpu_var(hv_24x7_hw);
+
+put_reqb:
+	put_cpu_var(hv_24x7_resb);
+	put_cpu_var(hv_24x7_reqb);
+out:
+	reset_txn();
+	return ret;
+}
+
+/*
+ * 24x7 counters only support READ transactions. They are always counting
+ * and dont need/support ADD transactions. However, regardless of type
+ * of transaction, all we need to do is cleanup, so we don't have to check
+ * the type of transaction.
+ */
+static void h_24x7_event_cancel_txn(struct pmu *pmu)
+{
+	WARN_ON_ONCE(!__this_cpu_read(hv_24x7_txn_flags));
+	reset_txn();
+}
+
 static struct pmu h_24x7_pmu = {
 	.task_ctx_nr = perf_invalid_context,
 
@@ -1266,6 +1425,9 @@ static struct pmu h_24x7_pmu = {
 	.start       = h_24x7_event_start,
 	.stop        = h_24x7_event_stop,
 	.read        = h_24x7_event_read,
+	.start_txn   = h_24x7_event_start_txn,
+	.commit_txn  = h_24x7_event_commit_txn,
+	.cancel_txn  = h_24x7_event_cancel_txn,
 };
 
 static int hv_24x7_init(void)