path: root/kernel/trace/trace_selftest.c

// SPDX-License-Identifier: GPL-2.0
/* Include in trace.c */

#include <uapi/linux/sched/types.h>
#include <linux/stringify.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/slab.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_STACK:
	case TRACE_PRINT:
	case TRACE_BRANCH:
	case TRACE_GRAPH_ENT:
	case TRACE_GRAPH_RETADDR_ENT:
	case TRACE_GRAPH_RET:
		return 1;
	}
	return 0;
}

static int trace_test_buffer_cpu(struct array_buffer *buf, int cpu)
{
	struct ring_buffer_event *event;
	struct trace_entry *entry;
	unsigned int loops = 0;

	while ((event = ring_buffer_consume(buf->buffer, cpu, NULL, 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 __maybe_unused trace_test_buffer(struct array_buffer *buf, unsigned long *count)
{
	unsigned long flags, cnt = 0;
	int cpu, ret = 0;

	/* Don't allow flipping of max traces now */
	local_irq_save(flags);
	arch_spin_lock(&buf->tr->max_lock);

	cnt = ring_buffer_entries(buf->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(buf, cpu);
		if (ret)
			break;
	}
	tracing_on();
	arch_spin_unlock(&buf->tr->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

static int trace_selftest_test_probe1_cnt;
static void trace_selftest_test_probe1_func(unsigned long ip,
					    unsigned long pip,
					    struct ftrace_ops *op,
					    struct ftrace_regs *fregs)
{
	trace_selftest_test_probe1_cnt++;
}

static int trace_selftest_test_probe2_cnt;
static void trace_selftest_test_probe2_func(unsigned long ip,
					    unsigned long pip,
					    struct ftrace_ops *op,
					    struct ftrace_regs *fregs)
{
	trace_selftest_test_probe2_cnt++;
}

static int trace_selftest_test_probe3_cnt;
static void trace_selftest_test_probe3_func(unsigned long ip,
					    unsigned long pip,
					    struct ftrace_ops *op,
					    struct ftrace_regs *fregs)
{
	trace_selftest_test_probe3_cnt++;
}

static int trace_selftest_test_global_cnt;
static void trace_selftest_test_global_func(unsigned long ip,
					    unsigned long pip,
					    struct ftrace_ops *op,
					    struct ftrace_regs *fregs)
{
	trace_selftest_test_global_cnt++;
}

static int trace_selftest_test_dyn_cnt;
static void trace_selftest_test_dyn_func(unsigned long ip,
					 unsigned long pip,
					 struct ftrace_ops *op,
					 struct ftrace_regs *fregs)
{
	trace_selftest_test_dyn_cnt++;
}

static struct ftrace_ops test_probe1 = {
	.func			= trace_selftest_test_probe1_func,
};

static struct ftrace_ops test_probe2 = {
	.func			= trace_selftest_test_probe2_func,
};

static struct ftrace_ops test_probe3 = {
	.func			= trace_selftest_test_probe3_func,
};

static void print_counts(void)
{
	printk("(%d %d %d %d %d) ",
	       trace_selftest_test_probe1_cnt,
	       trace_selftest_test_probe2_cnt,
	       trace_selftest_test_probe3_cnt,
	       trace_selftest_test_global_cnt,
	       trace_selftest_test_dyn_cnt);
}

static void reset_counts(void)
{
	trace_selftest_test_probe1_cnt = 0;
	trace_selftest_test_probe2_cnt = 0;
	trace_selftest_test_probe3_cnt = 0;
	trace_selftest_test_global_cnt = 0;
	trace_selftest_test_dyn_cnt = 0;
}

static int trace_selftest_ops(struct trace_array *tr, int cnt)
{
	int save_ftrace_enabled = ftrace_enabled;
	struct ftrace_ops *dyn_ops;
	char *func1_name;
	char *func2_name;
	int len1;
	int len2;
	int ret = -1;

	printk(KERN_CONT "PASSED\n");
	pr_info("Testing dynamic ftrace ops #%d: ", cnt);

	ftrace_enabled = 1;
	reset_counts();

	/* Handle PPC64 '.' name */
	func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
	func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2);
	len1 = strlen(func1_name);
	len2 = strlen(func2_name);

	/*
	 * Probe 1 will trace function 1.
	 * Probe 2 will trace function 2.
	 * Probe 3 will trace functions 1 and 2.
	 */
	ftrace_set_filter(&test_probe1, func1_name, len1, 1);
	ftrace_set_filter(&test_probe2, func2_name, len2, 1);
	ftrace_set_filter(&test_probe3, func1_name, len1, 1);
	ftrace_set_filter(&test_probe3, func2_name, len2, 0);

	register_ftrace_function(&test_probe1);
	register_ftrace_function(&test_probe2);
	register_ftrace_function(&test_probe3);
	/* First time we are running with main function */
	if (cnt > 1) {
		ftrace_init_array_ops(tr, trace_selftest_test_global_func);
		register_ftrace_function(tr->ops);
	}

	DYN_FTRACE_TEST_NAME();

	print_counts();

	if (trace_selftest_test_probe1_cnt != 1)
		goto out;
	if (trace_selftest_test_probe2_cnt != 0)
		goto out;
	if (trace_selftest_test_probe3_cnt != 1)
		goto out;
	if (cnt > 1) {
		if (trace_selftest_test_global_cnt == 0)
			goto out;
	}

	DYN_FTRACE_TEST_NAME2();

	print_counts();

	if (trace_selftest_test_probe1_cnt != 1)
		goto out;
	if (trace_selftest_test_probe2_cnt != 1)
		goto out;
	if (trace_selftest_test_probe3_cnt != 2)
		goto out;

	/* Add a dynamic probe */
	dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL);
	if (!dyn_ops) {
		printk("MEMORY ERROR ");
		goto out;
	}

	dyn_ops->func = trace_selftest_test_dyn_func;

	register_ftrace_function(dyn_ops);

	trace_selftest_test_global_cnt = 0;

	DYN_FTRACE_TEST_NAME();

	print_counts();

	if (trace_selftest_test_probe1_cnt != 2)
		goto out_free;
	if (trace_selftest_test_probe2_cnt != 1)
		goto out_free;
	if (trace_selftest_test_probe3_cnt != 3)
		goto out_free;
	if (cnt > 1) {
		if (