[linux-block.git] / kernel / kcsan / debugfs.c

// SPDX-License-Identifier: GPL-2.0

#include <linux/atomic.h>
#include <linux/bsearch.h>
#include <linux/bug.h>
#include <linux/debugfs.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/string.h>
#include <linux/uaccess.h>

#include "kcsan.h"

/*
 * Statistics counters.
 */
static atomic_long_t counters[KCSAN_COUNTER_COUNT];

/*
 * Addresses for filtering functions from reporting. This list can be used as a
 * whitelist or blacklist.
 */
static struct {
	unsigned long	*addrs;		/* array of addresses */
	size_t		size;		/* current size */
	int		used;		/* number of elements used */
	bool		sorted;		/* if elements are sorted */
	bool		whitelist;	/* if list is a blacklist or whitelist */
} report_filterlist = {
	.addrs		= NULL,
	.size		= 8,		/* small initial size */
	.used		= 0,
	.sorted		= false,
	.whitelist	= false,	/* default is blacklist */
};
static DEFINE_SPINLOCK(report_filterlist_lock);

static const char *counter_to_name(enum kcsan_counter_id id)
{
	switch (id) {
	case KCSAN_COUNTER_USED_WATCHPOINTS:		return "used_watchpoints";
	case KCSAN_COUNTER_SETUP_WATCHPOINTS:		return "setup_watchpoints";
	case KCSAN_COUNTER_DATA_RACES:			return "data_races";
	case KCSAN_COUNTER_ASSERT_FAILURES:		return "assert_failures";
	case KCSAN_COUNTER_NO_CAPACITY:			return "no_capacity";
	case KCSAN_COUNTER_REPORT_RACES:		return "report_races";
	case KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN:	return "races_unknown_origin";
	case KCSAN_COUNTER_UNENCODABLE_ACCESSES:	return "unencodable_accesses";
	case KCSAN_COUNTER_ENCODING_FALSE_POSITIVES:	return "encoding_false_positives";
	case KCSAN_COUNTER_COUNT:
		BUG();
	}
	return NULL;
}

void kcsan_counter_inc(enum kcsan_counter_id id)
{
	atomic_long_inc(&counters[id]);
}

void kcsan_counter_dec(enum kcsan_counter_id id)
{
	atomic_long_dec(&counters[id]);
}

/*
 * The microbenchmark allows benchmarking KCSAN core runtime only. To run
 * multiple threads, pipe 'microbench=<iters>' from multiple tasks into the
 * debugfs file. This will not generate any conflicts, and tests fast-path only.
 */
static noinline void microbenchmark(unsigned long iters)
{
	cycles_t cycles;

	pr_info("KCSAN: %s begin | iters: %lu\n", __func__, iters);

	cycles = get_cycles();
	while (iters--) {
		/*
		 * We can run this benchmark from multiple tasks; this address
		 * calculation increases likelyhood of some accesses
		 * overlapping. Make the access type an atomic read, to never
		 * set up watchpoints and test the fast-path only.
		 */
		unsigned long addr =
			iters % (CONFIG_KCSAN_NUM_WATCHPOINTS * PAGE_SIZE);
		__kcsan_check_access((void *)addr, sizeof(long), KCSAN_ACCESS_ATOMIC);
	}
	cycles = get_cycles() - cycles;

	pr_info("KCSAN: %s end   | cycles: %llu\n", __func__, cycles);
}

/*
 * Simple test to create conflicting accesses. Write 'test=<iters>' to KCSAN's
 * debugfs file from multiple tasks to generate real conflicts and show reports.
 */
static long test_dummy;
static long test_flags;
static noinline void test_thread(unsigned long iters)
{
	const long CHANGE_BITS = 0xff00ff00ff00ff00L;
	const struct kcsan_ctx ctx_save = current->kcsan_ctx;
	cycles_t cycles;

	/* We may have been called from an atomic region; reset context. */
	memset(&current->kcsan_ctx, 0, sizeof(current->kcsan_ctx));

	pr_info("KCSAN: %s begin | iters: %lu\n", __func__, iters);
	pr_info("test_dummy@%px, test_flags@%px\n", &test_dummy, &test_flags);

	cycles = get_cycles();
	while (iters--) {
		/* These all should generate reports. */
		__kcsan_check_read(&test_dummy, sizeof(test_dummy));
		ASSERT_EXCLUSIVE_WRITER(test_dummy);
		ASSERT_EXCLUSIVE_ACCESS(test_dummy);

		ASSERT_EXCLUSIVE_BITS(test_flags, ~CHANGE_BITS); /* no report */
		__kcsan_check_read(&test_flags, sizeof(test_flags)); /* no report */

		ASSERT_EXCLUSIVE_BITS(test_flags, CHANGE_BITS); /* report */
		__kcsan_check_read(&test_flags, sizeof(test_flags)); /* no report */

		/* not actually instrumented */
		WRITE_ONCE(test_dummy, iters);  /* to observe value-change */
		__kcsan_check_write(&test_dummy, sizeof(test_dummy));

		test_flags ^= CHANGE_BITS; /* generate value-change */
		__kcsan_check_write(&test_flags, sizeof(test_flags));
	}
	cycles = get_cycles() - cycles;

	pr_info("KCSAN: %s end   | cycles: %llu\n", __func__, cycles);

	/* restore context */
	current->kcsan_ctx = ctx_save;
}

static int cmp_filterlist_addrs(const void *rhs, const void *lhs)
{
	const unsigned long a = *(const unsigned long *)rhs;
	const unsigned long b = *(const unsigned long *)lhs;

	return a < b ? -1 : a == b ? 0 : 1;
}

bool kcsan_skip_report_debugfs(unsigned long func_addr)
{
	unsigned long symbolsize, offset;
	unsigned long flags;
	bool ret = false;

	if (!kallsyms_lookup_size_offset(func_addr, &symbolsize, &offset))
		return false;
	func_addr -= offset; /* Get function start */

	spin_lock_irqsave(&report_filterlist_lock, flags);
	if (report_filterlist.used == 0)
		goto out;

	/* Sort array if it is unsorted, and then do a binary search. */
	if (!report_filterlist.sorted) {
		sort(report_filterlist.addrs, report_filterlist.used,
		     sizeof(unsigned long), cmp_filterlist_addrs, NULL);
		report_filterlist.sorted = true;
	}
	ret = !!bsearch(&func_addr, report_filterlist.addrs,
			report_filterlist.used, sizeof(unsigned long),
			cmp_filterlist_addrs);
	if (report_filterlist.whitelist)
		ret = !ret;

out:
	spin_unlock_irqrestore(&report_filterlist_lock, flags);
	return ret;
}

static void set_report_filterlist_whitelist(bool whitelist)
{
	unsigned long flags;

	spin_lock_irqsave(&report_filterlist_lock, flags);
	report_filterlist.whitelist = whitelist;
	spin_unlock_irqrestore(&report_filterlist_lock, flags);
}

/* Returns 0 on success, error-code otherwise. */
static ssize_t insert_report_filterlist(const char *func)
{
	unsigned long flags;
	unsigned long addr = kallsyms_lookup_name(func);
	ssize_t ret = 0;

	if (!addr) {
		pr_err("KCSAN: could not find function: '%s'\n", func);
		return -ENOENT;
	}

	spin_lock_irqsave(&report_filterlist_lock, flags);

	if (report_filterlist.addrs == NULL) {
		/* initial allocation */
		report_filterlist.addrs =
			kmalloc_array(report_filterlist.size,
				      sizeof(unsigned long), GFP_KERNEL);
		if (report_filterlist.addrs == NULL) {
			ret = -ENOMEM;
			goto out;
		}
	} else if (report_filterlist.used == report_filterlist.size) {
		/* resize filterlist */
		size_t new_size = report_filterlist.size * 2;
		unsigned long *new_addrs =
			krealloc(report_filterlist.addrs,
				 new_size * sizeof(unsigned long), GFP_KERNEL);

		if (new_addrs == NULL) {
			/* leave filterlist itself untouched */
			ret = -ENOMEM;
			goto out;
		}

		report_filterlist.size = new_size;
		report_filterlist.addrs = new_addrs;
	}

	/* Note: deduplicating should be done in userspace. */
	report_filterlist.addrs[report_filterlist.used++] =
		kallsyms_lookup_name(func);
	report_filterlist.sorted = false;

out:
	spin_unlock_irqrestore(&report_filterlist_lock, flags);

	return ret;
}

static int show_info(struct seq_file *file, void *v)
{
	int i;
	unsigned long flags;

	/* show stats */
	seq_printf(file, "enabled: %i\n", READ_ONCE(kcsan_enabled));
	for (i = 0; i < KCSAN_COUNTER_COUNT; ++i)
		seq_printf(file, "%s: %ld\n", counter_to_name(i),
			   atomic_long_read(&counters[i]));

	/* show filter functions, and filter type */
	spin_lock_irqsave(&report_filterlist_lock, flags);
	seq_printf(file, "\n%s functions: %s\n",
		   report_filterlist.whitelist ? "whitelisted" : "blacklisted",
		   report_filterlist.used == 0 ? "none" : "");
	for (i = 0; i < report_filterlist.used; ++i)
		seq_printf(file, " %ps\n", (void *)report_filterlist.addrs[i]);
	spin_unlock_irqrestore(&report_filterlist_lock, flags);

	return 0;
}

static int debugfs_open(struct inode *inode, struct file *file)
{
	return single_open(file, show_info, NULL);
}

static ssize_t
debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *off)
{
	char kbuf[KSYM_NAME_LEN];
	char *arg;
	int read_len = count < (sizeof(kbuf) - 1) ? count : (sizeof(kbuf) - 1);

	if (copy_from_user(kbuf, buf, read_len))
		return -EFAULT;
	kbuf[read_len] = '\0';
	arg = strstrip(kbuf);

	if (!strcmp(arg, "on")) {
		WRITE_ONCE(kcsan_enabled, true);
	} else if (!strcmp(arg, "off")) {
		WRITE_ONCE(kcsan_enabled, false);
	} else if (!strncmp(arg, "microbench=", sizeof("microbench=") - 1)) {
		unsigned long iters;

		if (kstrtoul(&arg[sizeof("microbench=") - 1], 0, &iters))
			return -EINVAL;
		microbenchmark(iters);
	} else if (!strncmp(arg, "test=", sizeof("test=") - 1)) {
		unsigned long iters;

		if (kstrtoul(&arg[sizeof("test=") - 1], 0, &iters))
			return -EINVAL;
		test_thread(iters);
	} else if (!strcmp(arg, "whitelist")) {
		set_report_filterlist_whitelist(true);
	} else if (!strcmp(arg, "blacklist")) {
		set_report_filterlist_whitelist(false);
	} else if (arg[0] == '!') {
		ssize_t ret = insert_report_filterlist(&arg[1]);

		if (ret < 0)
			return ret;
	} else {
		return -EINVAL;
	}

	return count;
}

static const struct file_operations debugfs_ops =
{
	.read	 = seq_read,
	.open	 = debugfs_open,
	.write	 = debugfs_write,
	.release = single_release
};

void __init kcsan_debugfs_init(void)
{
	debugfs_create_file("kcsan", 0644, NULL, NULL, &debugfs_ops);
}
Commit	Line	Data
dfd402a4 ME	1	// SPDX-License-Identifier: GPL-2.0
	2
	3	#include <linux/atomic.h>
	4	#include <linux/bsearch.h>
	5	#include <linux/bug.h>
	6	#include <linux/debugfs.h>
	7	#include <linux/init.h>
	8	#include <linux/kallsyms.h>
a3120135	9	#include <linux/sched.h>
dfd402a4 ME	10	#include <linux/seq_file.h>
	11	#include <linux/slab.h>
	12	#include <linux/sort.h>
	13	#include <linux/string.h>
	14	#include <linux/uaccess.h>
	15
	16	#include "kcsan.h"
	17
	18	/*
	19	* Statistics counters.
	20	*/
	21	static atomic_long_t counters[KCSAN_COUNTER_COUNT];
	22
	23	/*
	24	* Addresses for filtering functions from reporting. This list can be used as a
	25	* whitelist or blacklist.
	26	*/
	27	static struct {
5cbaefe9 IM	28	unsigned long addrs; / array of addresses */
	29	size_t size; /* current size */
	30	int used; /* number of elements used */
	31	bool sorted; /* if elements are sorted */
	32	bool whitelist; /* if list is a blacklist or whitelist */
dfd402a4	33	} report_filterlist = {
5cbaefe9 IM	34	.addrs = NULL,
	35	.size = 8, /* small initial size */
	36	.used = 0,
	37	.sorted = false,
	38	.whitelist = false, /* default is blacklist */
dfd402a4 ME	39	};
	40	static DEFINE_SPINLOCK(report_filterlist_lock);
	41
	42	static const char *counter_to_name(enum kcsan_counter_id id)
	43	{
	44	switch (id) {
5cbaefe9 IM	45	case KCSAN_COUNTER_USED_WATCHPOINTS: return "used_watchpoints";
	46	case KCSAN_COUNTER_SETUP_WATCHPOINTS: return "setup_watchpoints";
	47	case KCSAN_COUNTER_DATA_RACES: return "data_races";
d591ec3d	48	case KCSAN_COUNTER_ASSERT_FAILURES: return "assert_failures";
5cbaefe9 IM	49	case KCSAN_COUNTER_NO_CAPACITY: return "no_capacity";
	50	case KCSAN_COUNTER_REPORT_RACES: return "report_races";
	51	case KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN: return "races_unknown_origin";
	52	case KCSAN_COUNTER_UNENCODABLE_ACCESSES: return "unencodable_accesses";
	53	case KCSAN_COUNTER_ENCODING_FALSE_POSITIVES: return "encoding_false_positives";
dfd402a4 ME	54	case KCSAN_COUNTER_COUNT:
	55	BUG();
	56	}
	57	return NULL;
	58	}
	59
	60	void kcsan_counter_inc(enum kcsan_counter_id id)
	61	{
	62	atomic_long_inc(&counters[id]);
	63	}
	64
	65	void kcsan_counter_dec(enum kcsan_counter_id id)
	66	{
	67	atomic_long_dec(&counters[id]);
	68	}
	69
	70	/*
	71	* The microbenchmark allows benchmarking KCSAN core runtime only. To run
	72	* multiple threads, pipe 'microbench=<iters>' from multiple tasks into the
a3120135	73	* debugfs file. This will not generate any conflicts, and tests fast-path only.
dfd402a4	74	*/
a3120135	75	static noinline void microbenchmark(unsigned long iters)
dfd402a4 ME	76	{
	77	cycles_t cycles;
	78
	79	pr_info("KCSAN: %s begin \| iters: %lu\n", __func__, iters);
	80
	81	cycles = get_cycles();
	82	while (iters--) {
	83	/*
	84	* We can run this benchmark from multiple tasks; this address
a3120135 ME	85	* calculation increases likelyhood of some accesses
	86	* overlapping. Make the access type an atomic read, to never
	87	* set up watchpoints and test the fast-path only.
dfd402a4 ME	88	*/
	89	unsigned long addr =
	90	iters % (CONFIG_KCSAN_NUM_WATCHPOINTS * PAGE_SIZE);
a3120135	91	__kcsan_check_access((void *)addr, sizeof(long), KCSAN_ACCESS_ATOMIC);
dfd402a4 ME	92	}
	93	cycles = get_cycles() - cycles;
	94
	95	pr_info("KCSAN: %s end \| cycles: %llu\n", __func__, cycles);
	96	}
	97
a3120135 ME	98	/*
	99	* Simple test to create conflicting accesses. Write 'test=<iters>' to KCSAN's
	100	* debugfs file from multiple tasks to generate real conflicts and show reports.
	101	*/
	102	static long test_dummy;
703b3215	103	static long test_flags;
a3120135 ME	104	static noinline void test_thread(unsigned long iters)
a3120135 ME	105	{
703b3215	106	const long CHANGE_BITS = 0xff00ff00ff00ff00L;
a3120135 ME	107	const struct kcsan_ctx ctx_save = current->kcsan_ctx;
	108	cycles_t cycles;
	109
	110	/* We may have been called from an atomic region; reset context. */
	111	memset(&current->kcsan_ctx, 0, sizeof(current->kcsan_ctx));
	112
	113	pr_info("KCSAN: %s begin \| iters: %lu\n", __func__, iters);
703b3215	114	pr_info("test_dummy@%px, test_flags@%px\n", &test_dummy, &test_flags);
a3120135 ME	115
	116	cycles = get_cycles();
	117	while (iters--) {
703b3215	118	/* These all should generate reports. */
a3120135	119	__kcsan_check_read(&test_dummy, sizeof(test_dummy));
a3120135 ME	120	ASSERT_EXCLUSIVE_WRITER(test_dummy);
	121	ASSERT_EXCLUSIVE_ACCESS(test_dummy);
	122
703b3215 ME	123	ASSERT_EXCLUSIVE_BITS(test_flags, ~CHANGE_BITS); /* no report */
	124	__kcsan_check_read(&test_flags, sizeof(test_flags)); /* no report */
	125
	126	ASSERT_EXCLUSIVE_BITS(test_flags, CHANGE_BITS); /* report */
	127	__kcsan_check_read(&test_flags, sizeof(test_flags)); /* no report */
	128
a3120135 ME	129	/* not actually instrumented */
a3120135 ME	130	WRITE_ONCE(test_dummy, iters); /* to observe value-change */
703b3215 ME	131	__kcsan_check_write(&test_dummy, sizeof(test_dummy));
	132
	133	test_flags ^= CHANGE_BITS; /* generate value-change */
	134	__kcsan_check_write(&test_flags, sizeof(test_flags));
a3120135 ME	135	}
	136	cycles = get_cycles() - cycles;
	137
	138	pr_info("KCSAN: %s end \| cycles: %llu\n", __func__, cycles);
	139
	140	/* restore context */
	141	current->kcsan_ctx = ctx_save;
	142	}
	143
dfd402a4 ME	144	static int cmp_filterlist_addrs(const void rhs, const void lhs)
	145	{
	146	const unsigned long a = (const unsigned long )rhs;
	147	const unsigned long b = (const unsigned long )lhs;
	148
	149	return a < b ? -1 : a == b ? 0 : 1;
	150	}
	151
	152	bool kcsan_skip_report_debugfs(unsigned long func_addr)
	153	{
	154	unsigned long symbolsize, offset;
	155	unsigned long flags;
	156	bool ret = false;
	157
	158	if (!kallsyms_lookup_size_offset(func_addr, &symbolsize, &offset))
	159	return false;
5cbaefe9	160	func_addr -= offset; /* Get function start */
dfd402a4 ME	161
	162	spin_lock_irqsave(&report_filterlist_lock, flags);
	163	if (report_filterlist.used == 0)
	164	goto out;
	165
	166	/* Sort array if it is unsorted, and then do a binary search. */
	167	if (!report_filterlist.sorted) {
	168	sort(report_filterlist.addrs, report_filterlist.used,
	169	sizeof(unsigned long), cmp_filterlist_addrs, NULL);
	170	report_filterlist.sorted = true;
	171	}
	172	ret = !!bsearch(&func_addr, report_filterlist.addrs,
	173	report_filterlist.used, sizeof(unsigned long),
	174	cmp_filterlist_addrs);
	175	if (report_filterlist.whitelist)
	176	ret = !ret;
	177
	178	out:
	179	spin_unlock_irqrestore(&report_filterlist_lock, flags);
	180	return ret;
	181	}
	182
	183	static void set_report_filterlist_whitelist(bool whitelist)
	184	{
	185	unsigned long flags;
	186
	187	spin_lock_irqsave(&report_filterlist_lock, flags);
	188	report_filterlist.whitelist = whitelist;
	189	spin_unlock_irqrestore(&report_filterlist_lock, flags);
	190	}
	191
	192	/* Returns 0 on success, error-code otherwise. */
	193	static ssize_t insert_report_filterlist(const char *func)
	194	{
	195	unsigned long flags;
	196	unsigned long addr = kallsyms_lookup_name(func);
	197	ssize_t ret = 0;
	198
	199	if (!addr) {
	200	pr_err("KCSAN: could not find function: '%s'\n", func);
	201	return -ENOENT;
	202	}
	203
	204	spin_lock_irqsave(&report_filterlist_lock, flags);
	205
	206	if (report_filterlist.addrs == NULL) {
	207	/* initial allocation */
	208	report_filterlist.addrs =
	209	kmalloc_array(report_filterlist.size,
	210	sizeof(unsigned long), GFP_KERNEL);
	211	if (report_filterlist.addrs == NULL) {
	212	ret = -ENOMEM;
	213	goto out;
	214	}
	215	} else if (report_filterlist.used == report_filterlist.size) {
	216	/* resize filterlist */
	217	size_t new_size = report_filterlist.size * 2;
	218	unsigned long *new_addrs =
	219	krealloc(report_filterlist.addrs,
	220	new_size * sizeof(unsigned long), GFP_KERNEL);
	221
	222	if (new_addrs == NULL) {
	223	/* leave filterlist itself untouched */
	224	ret = -ENOMEM;
225	goto out;
226	}
227
228	report_filterlist.size = new_size;
229	report_filterlist.addrs = new_addrs;
230	}
231
232	/* Note: deduplicating should be done in userspace. */
233	report_filterlist.addrs[report_filterlist.used++] =
234	kallsyms_lookup_name(func);
235	report_filterlist.sorted = false;
236
237	out:
238	spin_unlock_irqrestore(&report_filterlist_lock, flags);
5cbaefe9	239
dfd402a4 ME	240	return ret;
	241	}
	242
	243	static int show_info(struct seq_file file, void v)
	244	{
	245	int i;
	246	unsigned long flags;
	247
	248	/* show stats */
	249	seq_printf(file, "enabled: %i\n", READ_ONCE(kcsan_enabled));
	250	for (i = 0; i < KCSAN_COUNTER_COUNT; ++i)
	251	seq_printf(file, "%s: %ld\n", counter_to_name(i),
	252	atomic_long_read(&counters[i]));
	253
	254	/* show filter functions, and filter type */
	255	spin_lock_irqsave(&report_filterlist_lock, flags);
	256	seq_printf(file, "\n%s functions: %s\n",
	257	report_filterlist.whitelist ? "whitelisted" : "blacklisted",
	258	report_filterlist.used == 0 ? "none" : "");
	259	for (i = 0; i < report_filterlist.used; ++i)
	260	seq_printf(file, " %ps\n", (void *)report_filterlist.addrs[i]);
	261	spin_unlock_irqrestore(&report_filterlist_lock, flags);
	262
	263	return 0;
	264	}
	265
	266	static int debugfs_open(struct inode inode, struct file file)
	267	{
	268	return single_open(file, show_info, NULL);
	269	}
	270
5cbaefe9 IM	271	static ssize_t
5cbaefe9 IM	272	debugfs_write(struct file file, const char __user buf, size_t count, loff_t *off)
dfd402a4 ME	273	{
	274	char kbuf[KSYM_NAME_LEN];
	275	char *arg;
	276	int read_len = count < (sizeof(kbuf) - 1) ? count : (sizeof(kbuf) - 1);
	277
	278	if (copy_from_user(kbuf, buf, read_len))
	279	return -EFAULT;
	280	kbuf[read_len] = '\0';
	281	arg = strstrip(kbuf);
	282
	283	if (!strcmp(arg, "on")) {
	284	WRITE_ONCE(kcsan_enabled, true);
	285	} else if (!strcmp(arg, "off")) {
	286	WRITE_ONCE(kcsan_enabled, false);
	287	} else if (!strncmp(arg, "microbench=", sizeof("microbench=") - 1)) {
	288	unsigned long iters;
	289
	290	if (kstrtoul(&arg[sizeof("microbench=") - 1], 0, &iters))
	291	return -EINVAL;
	292	microbenchmark(iters);
a3120135 ME	293	} else if (!strncmp(arg, "test=", sizeof("test=") - 1)) {
	294	unsigned long iters;
	295
	296	if (kstrtoul(&arg[sizeof("test=") - 1], 0, &iters))
	297	return -EINVAL;
	298	test_thread(iters);
dfd402a4 ME	299	} else if (!strcmp(arg, "whitelist")) {
	300	set_report_filterlist_whitelist(true);
	301	} else if (!strcmp(arg, "blacklist")) {
	302	set_report_filterlist_whitelist(false);
	303	} else if (arg[0] == '!') {
	304	ssize_t ret = insert_report_filterlist(&arg[1]);
	305
	306	if (ret < 0)
	307	return ret;
	308	} else {
	309	return -EINVAL;
	310	}
	311
	312	return count;
	313	}
	314
5cbaefe9 IM	315	static const struct file_operations debugfs_ops =
	316	{
	317	.read = seq_read,
	318	.open = debugfs_open,
	319	.write = debugfs_write,
	320	.release = single_release
	321	};
dfd402a4 ME	322
	323	void __init kcsan_debugfs_init(void)
	324	{
	325	debugfs_create_file("kcsan", 0644, NULL, NULL, &debugfs_ops);
	326	}