/* Include in trace.c */
#include <linux/kthread.h>
#include <linux/delay.h>
static inline int trace_valid_entry(struct trace_entry *entry)
{
switch (entry->type) {
case TRACE_FN:
case TRACE_CTX:
case TRACE_WAKE:
case TRACE_CONT:
case TRACE_STACK:
case TRACE_PRINT:
case TRACE_SPECIAL:
case TRACE_BRANCH:
return 1;
}
return 0;
}
static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
{
struct ring_buffer_event *event;
struct trace_entry *entry;
unsigned int loops = 0;
while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) {
entry = ring_buffer_event_data(event);
/*
* The ring buffer is a size of trace_buf_size, if
* we loop more than the size, there's something wrong
* with the ring buffer.
*/
if (loops++ > trace_buf_size) {
printk(KERN_CONT ".. bad ring buffer ");
goto failed;
}
if (!trace_valid_entry(entry)) {
printk(KERN_CONT ".. invalid entry %d ",
entry->type);
goto failed;
}
}
return 0;
failed:
/* disable tracing */
tracing_disabled = 1;
printk(KERN_CONT ".. corrupted trace buffer .. ");
return -1;
}
/*
* Test the trace buffer to see if all the elements
* are still sane.
*/
static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
{
unsigned long flags, cnt = 0;
int cpu, ret = 0;
/* Don't allow flipping of max traces now */
local_irq_save(flags);
__raw_spin_lock(&ftrace_max_lock);
cnt = ring_buffer_entries(tr->buffer);
/*
* The trace_test_buffer_cpu runs a while loop to consume all data.
* If the calling tracer is broken, and is constantly filling
* the buffer, this will run forever, and hard lock the box.
* We disable the ring buffer while we do this test to prevent
* a hard lock up.
*/
tracing_off();
for_each_possible_cpu(cpu) {
ret = trace_test_buffer_cpu(tr, cpu);
if (ret)
break;
}
tracing_on();
__raw_spin_unlock(&ftrace_max_lock);
local_irq_restore(flags);
if (count)
*count = cnt;
return ret;
}
static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
{
printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n",
trace->name, init_ret);
}
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
#define __STR(x) #x
#define STR(x) __STR(x)
/* Test dynamic code modification and ftrace filters */
int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
struct trace_array *tr,
int (*func)(void))
{
int save_ftrace_enabled = ftrace_enabled;
int save_tracer_enabled = tracer_enabled;
unsigned long count;
char *func_name;
int ret;
/* The ftrace test PASSED */
printk(KERN_CONT "PASSED\n");
pr_info("Testing dynamic ftrace: ");
/* enable tracing, and record the filter function */
ftrace_enabled = 1;
tracer_enabled = 1;
/* passed in by parameter to fool gcc from optimizing */
func();
/*
* Some archs *cough*PowerPC*cough* add charachters to the
* start of the function names. We simply put a '*' to
* accomodate them.
*/
func_name = "*" STR(DYN_FTRACE_TEST_NAME);
/* filter only on our function */
ftrace_set_filter(func_name, strlen(func_name), 1);
/* enable tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
goto out;
}
/* Sleep for a 1/10 of a second */
msleep(100);
/* we should have nothing in the buffer */
ret = trace_test_buffer(tr, &count);
if (ret)
goto out;
if (count) {
ret = -1;
printk(KERN_CONT ".. filter did not filter .. ");
goto out;
}
/* call our function again */
func();
/* sleep again */
msleep(100);
/* stop the tracing. */
tracing_stop();
ftrace_enabled = 0;
/* check the trace buffer */
ret = trace_test_buffer(tr, &count);
trace->reset(tr);
tracing_start();
/* we should only have one item */
if (!ret && count != 1) {
printk(KERN_CONT ".. filter failed count=%ld ..", count);
ret = -1;
goto out;
}
out:
ftrace_enabled = save_ftrace_enabled;
tracer_enabled = save_tracer_enabled;
/* Enable tracing on all functions again */
ftrace_set_filter(NULL, 0, 1);
return ret;
}
#else
# define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
#endif /* CONFIG_DYNAMIC_FTRACE */
/*
* Simple verification test of ftrace function tracer.
* Enable ftrace, sleep 1/10 second, and then read the trace
* buffer to see if all is in order.
*/
int
trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
{
int save_ftrace_enabled = ftrace_enabled;
int save_tracer_enabled = tracer_enabled;
unsigned long count;
int ret;
/* make sure msleep has been recorded */
msleep(1);
/* start the tracing */
ftrace_enabled = 1;
tracer_enabled = 1;
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
goto out;
}
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
tracing_stop();
ftrace_enabled = 0;
/* check the trace buffer */
ret = trace_test_buffer(tr, &count);
trace->reset(tr);
tracing_start();
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
goto out;
}
ret = trace_selftest_startup_dynamic_tracing(trace, tr,
DYN_FTRACE_TEST_NAME);
out:
ftrace_enabled = save_ftrace_enabled;
tracer_enabled = save_tracer_enabled;
/* kill ftrace totally if we failed */
if (ret)
ftrace_kill();
return ret;
}
#endif /* CONFIG_FUNCTION_TRACER */
#ifdef CONFIG_IRQSOFF_TRACER
int
trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
{
unsigned long save_max = tracing_max_latency;
unsigned long count;
int ret;
/* start the tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
return ret;
}
/* reset the max latency */
tracing_max_latency = 0;
/* disable interrupts for a bit */
local_irq_disable();
udelay(100);
local_irq_enable();
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (!ret)
ret = trace_test_buffer(&max_tr, &count);
trace->reset(tr);
tracing_start();
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
}
tracing_max_latency = save_max;
return ret;
}
#endif /* CONFIG_IRQSOFF_TRACER */
#ifdef CONFIG_PREEMPT_TRACER
int
trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
{
unsigned long save_max = tracing_max_latency;
unsigned long count;
int ret;
/*
* Now that the big kernel lock is no longer preemptable,
* and this is called with the BKL held, it will always
* fail. If preemption is already disabled, simply
* pass the test. When the BKL is removed, or becomes
* preemptible again, we will once again test this,
* so keep it in.
*/
if (preempt_count()) {
printk(KERN_CONT "can not test ... force ");
return 0;
}
/* start the tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
return ret;
}
/* reset the max latency */
tracing_max_latency = 0;
/* disable preemption for a bit */
preempt_disable();
udelay(100);
preempt_enable();
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (!ret)
ret = trace_test_buffer(&max_tr, &count);
trace->reset(tr);
tracing_start();
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
}
tracing_max_latency = save_max;
return ret;
}
#endif /* CONFIG_PREEMPT_TRACER */
#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
int
trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
{
unsigned long save_max = tracing_max_latency;
unsigned long count;
int ret;
/*
* Now that the big kernel lock is no longer preemptable,
* and this is called with the BKL held, it will always
* fail. If preemption is already disabled, simply
* pass the test. When the BKL is removed, or becomes
* preemptible again, we will once again test this,
* so keep it in.
*/
if (preempt_count()) {
printk(KERN_CONT "can not test ... force ");
return 0;
}
/* start the tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
goto out;
}
/* reset the max latency */
tracing_max_latency = 0;
/* disable preemption and interrupts for a bit */
preempt_disable();
local_irq_disable();
udelay(100);
preempt_enable();
/* reverse the order of preempt vs irqs */
local_irq_enable();
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (ret) {
tracing_start();
goto out;
}
ret = trace_test_buffer(&max_tr, &count);
if (ret) {
tracing_start();
goto out;
}
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
tracing_start();
goto out;
}
/* do the test by disabling interrupts first this time */
tracing_max_latency = 0;
tracing_start();
preempt_disable();
local_irq_disable();
udelay(100);
preempt_enable();
/* reverse the order of preempt vs irqs */
local_irq_enable();
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (ret)
goto out;
ret = trace_test_buffer(&max_tr, &count);
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
goto out;
}
out:
trace->reset(tr);
tracing_start();
tracing_max_latency = save_max;
return ret;
}
#endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
#ifdef CONFIG_NOP_TRACER
int
trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
{
/* What could possibly go wrong? */
return 0;
}
#endif
#ifdef CONFIG_SCHED_TRACER
static int trace_wakeup_test_thread(void *data)
{
/* Make this a RT thread, doesn't need to be too high */
struct sched_param param = { .sched_priority = 5 };
struct completion *x = data;
sched_setscheduler(current, SCHED_FIFO, ¶m);
/* Make it know we have a new prio */
complete(x);
/* now go to sleep and let the test wake us up */
set_current_state(TASK_INTERRUPTIBLE);
schedule();
/* we are awake, now wait to disappear */
while (!kthread_should_stop()) {
/*
* This is an RT task, do short sleeps to let
* others run.
*/
msleep(100);
}
return 0;
}
int
trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
{
unsigned long save_max = tracing_max_latency;
struct task_struct *p;
struct completion isrt;
unsigned long count;
int ret;
init_completion(&isrt);
/* create a high prio thread */
p = kthread_run(trace_wakeup_test_thread, &isrt, "ftrace-test");
if (IS_ERR(p)) {
printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
return -1;
}
/* make sure the thread is running at an RT prio */
wait_for_completion(&isrt);
/* start the tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
return ret;
}
/* reset the max latency */
tracing_max_latency = 0;
/* sleep to let the RT thread sleep too */
msleep(100);
/*
* Yes this is slightly racy. It is possible that for some
* strange reason that the RT thread we created, did not
* call schedule for 100ms after doing the completion,
* and we do a wakeup on a task that already is awake.
* But that is extremely unlikely, and the worst thing that
* happens in such a case, is that we disable tracing.
* Honestly, if this race does happen something is horrible
* wrong with the system.
*/
wake_up_process(p);
/* give a little time to let the thread wake up */
msleep(100);
/* stop the tracing. */
tracing_stop();
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (!ret)
ret = trace_test_buffer(&max_tr, &count);
trace->reset(tr);
tracing_start();
tracing_max_latency = save_max;
/* kill the thread */
kthread_stop(p);
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
}
return ret;
}
#endif /* CONFIG_SCHED_TRACER */
#ifdef CONFIG_CONTEXT_SWITCH_TRACER
int
trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr)
{
unsigned long count;
int ret;
/* start the tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
return ret;
}
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
tracing_stop();
/* check the trace buffer */
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_CONTEXT_SWITCH_TRACER */
#ifdef CONFIG_SYSPROF_TRACER
int
trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
{
unsigned long count;
int ret;
/* start the tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
return 0;
}
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
tracing_stop();
/* check the trace buffer */
ret = trace_test_buffer(tr, &count);
trace->reset(tr);
tracing_start();
return ret;
}
#endif /* CONFIG_SYSPROF_TRACER */
#ifdef CONFIG_BRANCH_TRACER
int
trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
{
unsigned long count;
int ret;
/* start the tracing */
ret = trace->init(tr);
if (ret) {
warn_failed_init_tracer(trace, ret);
return ret;
}
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
tracing_stop();
/* check the trace buffer */
ret = trace_test_buffer(tr, &count);
trace->reset(tr);
tracing_start();
return ret;
}
#endif /* CONFIG_BRANCH_TRACER */
