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linux-2.6/kernel/trace/trace_selftest.c

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/* Include in trace.c */
#include <linux/kthread.h>
static inline int trace_valid_entry(struct trace_entry *entry)
{
switch (entry->type) {
case TRACE_FN:
case TRACE_CTX:
return 1;
}
return 0;
}
static int
trace_test_buffer_cpu(struct trace_array *tr, struct trace_array_cpu *data)
{
struct page *page;
struct trace_entry *entries;
int idx = 0;
int i;
page = list_entry(data->trace_pages.next, struct page, lru);
entries = page_address(page);
if (data->trace != entries)
goto failed;
/*
* The starting trace buffer always has valid elements,
* if any element exits.
*/
entries = data->trace;
for (i = 0; i < tr->entries; i++) {
if (i < data->trace_idx &&
!trace_valid_entry(&entries[idx])) {
printk(KERN_CONT ".. invalid entry %d ", entries[idx].type);
goto failed;
}
idx++;
if (idx >= ENTRIES_PER_PAGE) {
page = virt_to_page(entries);
if (page->lru.next == &data->trace_pages) {
if (i != tr->entries - 1) {
printk(KERN_CONT ".. entries buffer mismatch");
goto failed;
}
} else {
page = list_entry(page->lru.next, struct page, lru);
entries = page_address(page);
}
idx = 0;
}
}
page = virt_to_page(entries);
if (page->lru.next != &data->trace_pages) {
printk(KERN_CONT ".. too many entries");
goto failed;
}
return 0;
failed:
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 cnt = 0;
int cpu;
int ret = 0;
for_each_possible_cpu(cpu) {
if (!tr->data[cpu]->trace)
continue;
cnt += tr->data[cpu]->trace_idx;
printk("%d: count = %ld\n", cpu, cnt);
ret = trace_test_buffer_cpu(tr, tr->data[cpu]);
if (ret)
break;
}
if (count)
*count = cnt;
return ret;
}
#ifdef CONFIG_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)
{
unsigned long count;
int ret;
/* make sure functions have been recorded */
ret = ftrace_force_update();
if (ret) {
printk(KERN_CONT ".. ftraced failed .. ");
return ret;
}
/* start the tracing */
tr->ctrl = 1;
trace->init(tr);
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
tr->ctrl = 0;
trace->ctrl_update(tr);
/* check the trace buffer */
ret = trace_test_buffer(tr, &count);
trace->reset(tr);
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
}
return ret;
}
#endif /* CONFIG_FTRACE */
#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 */
tr->ctrl = 1;
trace->init(tr);
/* reset the max latency */
tracing_max_latency = 0;
/* disable interrupts for a bit */
local_irq_disable();
udelay(100);
local_irq_enable();
/* stop the tracing. */
tr->ctrl = 0;
trace->ctrl_update(tr);
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (!ret)
ret = trace_test_buffer(&max_tr, &count);
trace->reset(tr);
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;
/* start the tracing */
tr->ctrl = 1;
trace->init(tr);
/* reset the max latency */
tracing_max_latency = 0;
/* disable preemption for a bit */
preempt_disable();
udelay(100);
preempt_enable();
/* stop the tracing. */
tr->ctrl = 0;
trace->ctrl_update(tr);
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (!ret)
ret = trace_test_buffer(&max_tr, &count);
trace->reset(tr);
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;
/* start the tracing */
tr->ctrl = 1;
trace->init(tr);
/* 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. */
tr->ctrl = 0;
trace->ctrl_update(tr);
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (ret)
goto out;
ret = trace_test_buffer(&max_tr, &count);
if (ret)
goto out;
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
goto out;
}
/* do the test by disabling interrupts first this time */
tracing_max_latency = 0;
tr->ctrl = 1;
trace->ctrl_update(tr);
preempt_disable();
local_irq_disable();
udelay(100);
preempt_enable();
/* reverse the order of preempt vs irqs */
local_irq_enable();
/* stop the tracing. */
tr->ctrl = 0;
trace->ctrl_update(tr);
/* 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_max_latency = save_max;
return ret;
}
#endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
#ifdef CONFIG_SCHED_TRACER
static int trace_wakeup_test_thread(void *data)
{
struct completion *x = data;
/* Make this a RT thread, doesn't need to be too high */
rt_mutex_setprio(current, MAX_RT_PRIO - 5);
/* 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 */
tr->ctrl = 1;
trace->init(tr);
/* 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);
/* stop the tracing. */
tr->ctrl = 0;
trace->ctrl_update(tr);
/* check both trace buffers */
ret = trace_test_buffer(tr, NULL);
if (!ret)
ret = trace_test_buffer(&max_tr, &count);
trace->reset(tr);
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 */
tr->ctrl = 1;
trace->init(tr);
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
tr->ctrl = 0;
trace->ctrl_update(tr);
/* check the trace buffer */
ret = trace_test_buffer(tr, &count);
trace->reset(tr);
if (!ret && !count) {
printk(KERN_CONT ".. no entries found ..");
ret = -1;
}
return ret;
}
#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
#ifdef CONFIG_DYNAMIC_FTRACE
#endif /* CONFIG_DYNAMIC_FTRACE */