x86, hw-branch-tracer: add selftest

Add a selftest for the hw-branch-tracer.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
LKML-Reference: <20090313105027.A30183@sedona.ch.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 59 insertions, 1 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 56ce34d90b03..e7fbc826f1e9 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -576,6 +576,8 @@ extern int trace_selftest_startup_sysprof(struct tracer *trace,
                                                struct trace_array *tr);
 extern int trace_selftest_startup_branch(struct tracer *trace,
                                          struct trace_array *tr);
+extern int trace_selftest_startup_hw_branches(struct tracer *trace,
+                                              struct trace_array *tr);
 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 
 extern void *head_page(struct trace_array_cpu *data);
diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
index a99a04c5e9cd..4ca82700c04e 100644
--- a/kernel/trace/trace_hw_branches.c
+++ b/kernel/trace/trace_hw_branches.c
@@ -342,7 +342,10 @@ struct tracer bts_tracer __read_mostly =
         .start          = bts_trace_start,
         .stop           = bts_trace_stop,
         .open           = trace_bts_prepare,
-        .close          = trace_bts_close
+        .close          = trace_bts_close,
+#ifdef CONFIG_FTRACE_SELFTEST
+        .selftest       = trace_selftest_startup_hw_branches,
+#endif /* CONFIG_FTRACE_SELFTEST */
 };
 
 __init static int init_bts_trace(void)
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index f907a2b29028..3c7b797d0d28 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -16,6 +16,7 @@ static inline int trace_valid_entry(struct trace_entry *entry)
         case TRACE_BRANCH:
         case TRACE_GRAPH_ENT:
         case TRACE_GRAPH_RET:
+        case TRACE_HW_BRANCHES:
                 return 1;
         }
         return 0;
@@ -691,3 +692,55 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
         return ret;
 }
 #endif /* CONFIG_BRANCH_TRACER */
+
+#ifdef CONFIG_HW_BRANCH_TRACER
+int
+trace_selftest_startup_hw_branches(struct tracer *trace,
+                                   struct trace_array *tr)
+{
+        unsigned long count;
+        int ret;
+        struct trace_iterator iter;
+        struct tracer tracer;
+
+        if (!trace->open) {
+                printk(KERN_CONT "missing open function...");
+                return -1;
+        }
+
+        ret = tracer_init(trace, tr);
+        if (ret) {
+                warn_failed_init_tracer(trace, ret);
+                return ret;
+        }
+
+        /*
+         * The hw-branch tracer needs to collect the trace from the various
+         * cpu trace buffers - before tracing is stopped.
+         */
+        memset(&iter, 0, sizeof(iter));
+        memcpy(&tracer, trace, sizeof(tracer));
+
+        iter.trace = &tracer;
+        iter.tr = tr;
+        iter.pos = -1;
+        mutex_init(&iter.mutex);
+
+        trace->open(&iter);
+
+        mutex_destroy(&iter.mutex);
+
+        tracing_stop();
+
+        ret = trace_test_buffer(tr, &count);
+        trace->reset(tr);
+        tracing_start();
+
+        if (!ret && !count) {
+                printk(KERN_CONT "no entries found..");
+                ret = -1;
+        }
+
+        return ret;
+}
+#endif /* CONFIG_HW_BRANCH_TRACER */