s390/diag: add tracepoint for diagnose calls

To be able to analyse problems in regard to hypervisor overhead
add a tracepoing for diagnose calls. It reports the number of
the diagnose issued, e.g.

            sshd-1385  [002] ....    42.701431: diagnose: nr=0x9c
          <idle>-0     [001] ..s.    43.587528: diagnose: nr=0x9c

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/arch/s390/kernel/trace.c b/arch/s390/kernel/trace.c
new file mode 100644
index 000000000000..73239bb576c4
--- /dev/null
+++ b/arch/s390/kernel/trace.c
@@ -0,0 +1,29 @@
+/*
+ * Tracepoint definitions for s390
+ *
+ * Copyright IBM Corp. 2015
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/percpu.h>
+#define CREATE_TRACE_POINTS
+#include <asm/trace/diag.h>
+
+EXPORT_TRACEPOINT_SYMBOL(diagnose);
+
+static DEFINE_PER_CPU(unsigned int, diagnose_trace_depth);
+
+void trace_diagnose_norecursion(int diag_nr)
+{
+	unsigned long flags;
+	unsigned int *depth;
+
+	local_irq_save(flags);
+	depth = this_cpu_ptr(&diagnose_trace_depth);
+	if (*depth == 0) {
+		(*depth)++;
+		trace_diagnose(diag_nr);
+		(*depth)--;
+	}
+	local_irq_restore(flags);
+}