ftrace: add self-tests
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 9bad237..f6d026f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -32,6 +32,8 @@
unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX;
unsigned long __read_mostly tracing_thresh;
+static int tracing_disabled = 1;
+
static long notrace
ns2usecs(cycle_t nsec)
{
@@ -217,11 +219,48 @@
}
}
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+ if (type->selftest) {
+ struct tracer *saved_tracer = current_trace;
+ struct trace_array_cpu *data;
+ struct trace_array *tr = &global_trace;
+ int saved_ctrl = tr->ctrl;
+ int i;
+ /*
+ * Run a selftest on this tracer.
+ * Here we reset the trace buffer, and set the current
+ * tracer to be this tracer. The tracer can then run some
+ * internal tracing to verify that everything is in order.
+ * If we fail, we do not register this tracer.
+ */
+ for_each_possible_cpu(i) {
+ if (!data->trace)
+ continue;
+ data = tr->data[i];
+ tracing_reset(data);
+ }
+ current_trace = type;
+ tr->ctrl = 0;
+ /* the test is responsible for initializing and enabling */
+ pr_info("Testing tracer %s: ", type->name);
+ ret = type->selftest(type, tr);
+ /* the test is responsible for resetting too */
+ current_trace = saved_tracer;
+ tr->ctrl = saved_ctrl;
+ if (ret) {
+ printk(KERN_CONT "FAILED!\n");
+ goto out;
+ }
+ printk(KERN_CONT "PASSED\n");
+ }
+#endif
+
type->next = trace_types;
trace_types = type;
len = strlen(type->name);
if (len > max_tracer_type_len)
max_tracer_type_len = len;
+
out:
mutex_unlock(&trace_types_lock);
@@ -985,6 +1024,11 @@
{
struct trace_iterator *iter;
+ if (tracing_disabled) {
+ *ret = -ENODEV;
+ return NULL;
+ }
+
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter) {
*ret = -ENOMEM;
@@ -1023,6 +1067,9 @@
int tracing_open_generic(struct inode *inode, struct file *filp)
{
+ if (tracing_disabled)
+ return -ENODEV;
+
filp->private_data = inode->i_private;
return 0;
}
@@ -1128,6 +1175,9 @@
{
int ret;
+ if (tracing_disabled)
+ return -ENODEV;
+
ret = seq_open(file, &show_traces_seq_ops);
if (!ret) {
struct seq_file *m = file->private_data;
@@ -1452,6 +1502,11 @@
return d_tracer;
}
+#ifdef CONFIG_FTRACE_SELFTEST
+/* Let selftest have access to static functions in this file */
+#include "trace_selftest.c"
+#endif
+
static __init void tracer_init_debugfs(void)
{
struct dentry *d_tracer;
@@ -1585,6 +1640,7 @@
void *array;
struct page *page;
int pages = 0;
+ int ret = -ENOMEM;
int i;
/* Allocate the first page for all buffers */
@@ -1650,6 +1706,9 @@
register_tracer(&no_tracer);
current_trace = &no_tracer;
+ /* All seems OK, enable tracing */
+ tracing_disabled = 0;
+
return 0;
free_buffers:
@@ -1678,7 +1737,7 @@
}
#endif
}
- return -ENOMEM;
+ return ret;
}
-device_initcall(tracer_alloc_buffers);
+fs_initcall(tracer_alloc_buffers);