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Commit 60a11774 authored by Steven Rostedt's avatar Steven Rostedt Committed by Thomas Gleixner
Browse files

ftrace: add self-tests 



Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent e1c08bdd

kernel/trace/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -105,3 +105,16 @@ config DYNAMIC_FTRACE 
	 wakes up once a second and checks to see if any ftrace calls

	 were made. If so, it runs stop_machine (stops all CPUS)

	 and modifies the code to jump over the call to ftrace.



config FTRACE_SELFTEST

	bool



config FTRACE_STARTUP_TEST

	bool "Perform a startup test on ftrace"

	depends on TRACING

	select FTRACE_SELFTEST

	help

	  This option performs a series of startup tests on ftrace. On bootup

	  a series of tests are made to verify that the tracer is

	  functioning properly. It will do tests on all the configured

	  tracers of ftrace.

kernel/trace/trace.c

+61 −2
Original line number Diff line number Diff line
@@ -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 @@ int register_tracer(struct tracer *type) 
		}

	}



#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 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 
{

	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 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 


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 @@ static int show_traces_open(struct inode *inode, struct file *file) 
{

	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 @@ struct dentry *tracing_init_dentry(void) 
	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 @@ __init static int tracer_alloc_buffers(void) 
	void *array;

	struct page *page;

	int pages = 0;

	int ret = -ENOMEM;

	int i;



	/* Allocate the first page for all buffers */
@@ -1650,6 +1706,9 @@ __init static int tracer_alloc_buffers(void) 
	register_tracer(&no_tracer);

	current_trace = &no_tracer;



	/* All seems OK, enable tracing */

	tracing_disabled = 0;



	return 0;



 free_buffers:
@@ -1678,7 +1737,7 @@ __init static int tracer_alloc_buffers(void) 
		}

#endif

	}

	return -ENOMEM;

	return ret;

}



device_initcall(tracer_alloc_buffers);
 
fs_initcall(tracer_alloc_buffers);

kernel/trace/trace.h

+31 −0
Original line number Diff line number Diff line
@@ -99,6 +99,10 @@ struct tracer { 
	void			(*start)(struct trace_iterator *iter);

	void			(*stop)(struct trace_iterator *iter);

	void			(*ctrl_update)(struct trace_array *tr);

#ifdef CONFIG_FTRACE_STARTUP_TEST

	int			(*selftest)(struct tracer *trace,

					    struct trace_array *tr);

#endif

	struct tracer		*next;

	int			print_max;

};
@@ -185,4 +189,31 @@ extern int unregister_tracer_switch(struct tracer_switch_ops *ops); 
extern unsigned long ftrace_update_tot_cnt;

#endif



#ifdef CONFIG_FTRACE_STARTUP_TEST

#ifdef CONFIG_FTRACE

extern int trace_selftest_startup_function(struct tracer *trace,

					   struct trace_array *tr);

#endif

#ifdef CONFIG_IRQSOFF_TRACER

extern int trace_selftest_startup_irqsoff(struct tracer *trace,

					  struct trace_array *tr);

#endif

#ifdef CONFIG_PREEMPT_TRACER

extern int trace_selftest_startup_preemptoff(struct tracer *trace,

					     struct trace_array *tr);

#endif

#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)

extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,

						 struct trace_array *tr);

#endif

#ifdef CONFIG_SCHED_TRACER

extern int trace_selftest_startup_wakeup(struct tracer *trace,

					 struct trace_array *tr);

#endif

#ifdef CONFIG_CONTEXT_SWITCH_TRACER

extern int trace_selftest_startup_sched_switch(struct tracer *trace,

					       struct trace_array *tr);

#endif

#endif /* CONFIG_FTRACE_STARTUP_TEST */



#endif /* _LINUX_KERNEL_TRACE_H */

kernel/trace/trace_functions.c

+3 −0
Original line number Diff line number Diff line
@@ -63,6 +63,9 @@ static struct tracer function_trace __read_mostly = 
	.init	     = function_trace_init,

	.reset	     = function_trace_reset,

	.ctrl_update = function_trace_ctrl_update,

#ifdef CONFIG_FTRACE_SELFTEST

	.selftest    = trace_selftest_startup_function,

#endif

};



static __init int init_function_trace(void)

kernel/trace/trace_irqsoff.c

+9 −0
Original line number Diff line number Diff line
@@ -432,6 +432,9 @@ static struct tracer irqsoff_tracer __read_mostly = 
	.close		= irqsoff_tracer_close,

	.ctrl_update	= irqsoff_tracer_ctrl_update,

	.print_max	= 1,

#ifdef CONFIG_FTRACE_SELFTEST

	.selftest    = trace_selftest_startup_irqsoff,

#endif

};

# define register_irqsoff(trace) register_tracer(&trace)

#else
@@ -455,6 +458,9 @@ static struct tracer preemptoff_tracer __read_mostly = 
	.close		= irqsoff_tracer_close,

	.ctrl_update	= irqsoff_tracer_ctrl_update,

	.print_max	= 1,

#ifdef CONFIG_FTRACE_SELFTEST

	.selftest    = trace_selftest_startup_preemptoff,

#endif

};

# define register_preemptoff(trace) register_tracer(&trace)

#else
@@ -480,6 +486,9 @@ static struct tracer preemptirqsoff_tracer __read_mostly = 
	.close		= irqsoff_tracer_close,

	.ctrl_update	= irqsoff_tracer_ctrl_update,

	.print_max	= 1,

#ifdef CONFIG_FTRACE_SELFTEST

	.selftest    = trace_selftest_startup_preemptirqsoff,

#endif

};



# define register_preemptirqsoff(trace) register_tracer(&trace)