file.c 37.4 KB
Newer Older
1
// SPDX-License-Identifier: GPL-2.0
2 3 4 5 6 7 8
/*
 *  file.c - part of debugfs, a tiny little debug file system
 *
 *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
 *  Copyright (C) 2004 IBM Inc.
 *
 *  debugfs is for people to use instead of /proc or /sys.
9
 *  See Documentation/filesystems/ for more details.
10 11 12 13 14 15 16 17 18 19 20
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/debugfs.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/device.h>
21
#include <linux/poll.h>
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

#include "internal.h"

struct poll_table_struct;

static ssize_t default_read_file(struct file *file, char __user *buf,
				 size_t count, loff_t *ppos)
{
	return 0;
}

static ssize_t default_write_file(struct file *file, const char __user *buf,
				   size_t count, loff_t *ppos)
{
	return count;
}

const struct file_operations debugfs_noop_file_operations = {
	.read =		default_read_file,
	.write =	default_write_file,
	.open =		simple_open,
	.llseek =	noop_llseek,
};

46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
#define F_DENTRY(filp) ((filp)->f_path.dentry)

const struct file_operations *debugfs_real_fops(const struct file *filp)
{
	struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;

	if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) {
		/*
		 * Urgh, we've been called w/o a protecting
		 * debugfs_file_get().
		 */
		WARN_ON(1);
		return NULL;
	}

	return fsd->real_fops;
}
EXPORT_SYMBOL_GPL(debugfs_real_fops);

65
/**
66
 * debugfs_file_get - mark the beginning of file data access
67 68
 * @dentry: the dentry object whose data is being accessed.
 *
69 70 71
 * Up to a matching call to debugfs_file_put(), any successive call
 * into the file removing functions debugfs_remove() and
 * debugfs_remove_recursive() will block. Since associated private
72 73
 * file data may only get freed after a successful return of any of
 * the removal functions, you may safely access it after a successful
74
 * call to debugfs_file_get() without worrying about lifetime issues.
75 76 77 78 79
 *
 * If -%EIO is returned, the file has already been removed and thus,
 * it is not safe to access any of its data. If, on the other hand,
 * it is allowed to access the file data, zero is returned.
 */
80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110
int debugfs_file_get(struct dentry *dentry)
{
	struct debugfs_fsdata *fsd;
	void *d_fsd;

	d_fsd = READ_ONCE(dentry->d_fsdata);
	if (!((unsigned long)d_fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) {
		fsd = d_fsd;
	} else {
		fsd = kmalloc(sizeof(*fsd), GFP_KERNEL);
		if (!fsd)
			return -ENOMEM;

		fsd->real_fops = (void *)((unsigned long)d_fsd &
					~DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
		refcount_set(&fsd->active_users, 1);
		init_completion(&fsd->active_users_drained);
		if (cmpxchg(&dentry->d_fsdata, d_fsd, fsd) != d_fsd) {
			kfree(fsd);
			fsd = READ_ONCE(dentry->d_fsdata);
		}
	}

	/*
	 * In case of a successful cmpxchg() above, this check is
	 * strictly necessary and must follow it, see the comment in
	 * __debugfs_remove_file().
	 * OTOH, if the cmpxchg() hasn't been executed or wasn't
	 * successful, this serves the purpose of not starving
	 * removers.
	 */
111 112
	if (d_unlinked(dentry))
		return -EIO;
113 114 115 116

	if (!refcount_inc_not_zero(&fsd->active_users))
		return -EIO;

117 118
	return 0;
}
119
EXPORT_SYMBOL_GPL(debugfs_file_get);
120 121

/**
122 123 124
 * debugfs_file_put - mark the end of file data access
 * @dentry: the dentry object formerly passed to
 *          debugfs_file_get().
125 126 127
 *
 * Allow any ongoing concurrent call into debugfs_remove() or
 * debugfs_remove_recursive() blocked by a former call to
128
 * debugfs_file_get() to proceed and return to its caller.
129
 */
130
void debugfs_file_put(struct dentry *dentry)
131
{
132
	struct debugfs_fsdata *fsd = READ_ONCE(dentry->d_fsdata);
133

134 135 136 137
	if (refcount_dec_and_test(&fsd->active_users))
		complete(&fsd->active_users_drained);
}
EXPORT_SYMBOL_GPL(debugfs_file_put);
138 139 140

static int open_proxy_open(struct inode *inode, struct file *filp)
{
141
	struct dentry *dentry = F_DENTRY(filp);
142
	const struct file_operations *real_fops = NULL;
143
	int r;
144

145 146 147
	r = debugfs_file_get(dentry);
	if (r)
		return r == -EIO ? -ENOENT : r;
148

149
	real_fops = debugfs_real_fops(filp);
150 151 152 153 154 155 156 157 158 159 160 161 162 163
	real_fops = fops_get(real_fops);
	if (!real_fops) {
		/* Huh? Module did not clean up after itself at exit? */
		WARN(1, "debugfs file owner did not clean up at exit: %pd",
			dentry);
		r = -ENXIO;
		goto out;
	}
	replace_fops(filp, real_fops);

	if (real_fops->open)
		r = real_fops->open(inode, filp);

out:
164
	debugfs_file_put(dentry);
165 166 167 168 169 170 171 172 173 174 175 176 177
	return r;
}

const struct file_operations debugfs_open_proxy_file_operations = {
	.open = open_proxy_open,
};

#define PROTO(args...) args
#define ARGS(args...) args

#define FULL_PROXY_FUNC(name, ret_type, filp, proto, args)		\
static ret_type full_proxy_ ## name(proto)				\
{									\
178 179
	struct dentry *dentry = F_DENTRY(filp);			\
	const struct file_operations *real_fops;			\
180 181
	ret_type r;							\
									\
182 183 184 185 186 187
	r = debugfs_file_get(dentry);					\
	if (unlikely(r))						\
		return r;						\
	real_fops = debugfs_real_fops(filp);				\
	r = real_fops->name(args);					\
	debugfs_file_put(dentry);					\
188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208
	return r;							\
}

FULL_PROXY_FUNC(llseek, loff_t, filp,
		PROTO(struct file *filp, loff_t offset, int whence),
		ARGS(filp, offset, whence));

FULL_PROXY_FUNC(read, ssize_t, filp,
		PROTO(struct file *filp, char __user *buf, size_t size,
			loff_t *ppos),
		ARGS(filp, buf, size, ppos));

FULL_PROXY_FUNC(write, ssize_t, filp,
		PROTO(struct file *filp, const char __user *buf, size_t size,
			loff_t *ppos),
		ARGS(filp, buf, size, ppos));

FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
		PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
		ARGS(filp, cmd, arg));

209
static __poll_t full_proxy_poll(struct file *filp,
210 211
				struct poll_table_struct *wait)
{
212
	struct dentry *dentry = F_DENTRY(filp);
213
	__poll_t r = 0;
214
	const struct file_operations *real_fops;
215

216
	if (debugfs_file_get(dentry))
217
		return EPOLLHUP;
218

219
	real_fops = debugfs_real_fops(filp);
220
	r = real_fops->poll(filp, wait);
221
	debugfs_file_put(dentry);
222 223 224 225 226 227
	return r;
}

static int full_proxy_release(struct inode *inode, struct file *filp)
{
	const struct dentry *dentry = F_DENTRY(filp);
228
	const struct file_operations *real_fops = debugfs_real_fops(filp);
229 230 231 232 233 234 235 236 237 238 239 240 241 242 243
	const struct file_operations *proxy_fops = filp->f_op;
	int r = 0;

	/*
	 * We must not protect this against removal races here: the
	 * original releaser should be called unconditionally in order
	 * not to leak any resources. Releasers must not assume that
	 * ->i_private is still being meaningful here.
	 */
	if (real_fops->release)
		r = real_fops->release(inode, filp);

	replace_fops(filp, d_inode(dentry)->i_fop);
	kfree((void *)proxy_fops);
	fops_put(real_fops);
244
	return r;
245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264
}

static void __full_proxy_fops_init(struct file_operations *proxy_fops,
				const struct file_operations *real_fops)
{
	proxy_fops->release = full_proxy_release;
	if (real_fops->llseek)
		proxy_fops->llseek = full_proxy_llseek;
	if (real_fops->read)
		proxy_fops->read = full_proxy_read;
	if (real_fops->write)
		proxy_fops->write = full_proxy_write;
	if (real_fops->poll)
		proxy_fops->poll = full_proxy_poll;
	if (real_fops->unlocked_ioctl)
		proxy_fops->unlocked_ioctl = full_proxy_unlocked_ioctl;
}

static int full_proxy_open(struct inode *inode, struct file *filp)
{
265
	struct dentry *dentry = F_DENTRY(filp);
266 267
	const struct file_operations *real_fops = NULL;
	struct file_operations *proxy_fops = NULL;
268
	int r;
269

270 271 272
	r = debugfs_file_get(dentry);
	if (r)
		return r == -EIO ? -ENOENT : r;
273

274
	real_fops = debugfs_real_fops(filp);
275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309
	real_fops = fops_get(real_fops);
	if (!real_fops) {
		/* Huh? Module did not cleanup after itself at exit? */
		WARN(1, "debugfs file owner did not clean up at exit: %pd",
			dentry);
		r = -ENXIO;
		goto out;
	}

	proxy_fops = kzalloc(sizeof(*proxy_fops), GFP_KERNEL);
	if (!proxy_fops) {
		r = -ENOMEM;
		goto free_proxy;
	}
	__full_proxy_fops_init(proxy_fops, real_fops);
	replace_fops(filp, proxy_fops);

	if (real_fops->open) {
		r = real_fops->open(inode, filp);
		if (r) {
			replace_fops(filp, d_inode(dentry)->i_fop);
			goto free_proxy;
		} else if (filp->f_op != proxy_fops) {
			/* No protection against file removal anymore. */
			WARN(1, "debugfs file owner replaced proxy fops: %pd",
				dentry);
			goto free_proxy;
		}
	}

	goto out;
free_proxy:
	kfree(proxy_fops);
	fops_put(real_fops);
out:
310
	debugfs_file_put(dentry);
311 312 313 314 315 316 317 318 319 320
	return r;
}

const struct file_operations debugfs_full_proxy_file_operations = {
	.open = full_proxy_open,
};

ssize_t debugfs_attr_read(struct file *file, char __user *buf,
			size_t len, loff_t *ppos)
{
321
	struct dentry *dentry = F_DENTRY(file);
322 323
	ssize_t ret;

324 325 326 327 328
	ret = debugfs_file_get(dentry);
	if (unlikely(ret))
		return ret;
	ret = simple_attr_read(file, buf, len, ppos);
	debugfs_file_put(dentry);
329 330 331 332 333 334 335
	return ret;
}
EXPORT_SYMBOL_GPL(debugfs_attr_read);

ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
			 size_t len, loff_t *ppos)
{
336
	struct dentry *dentry = F_DENTRY(file);
337 338
	ssize_t ret;

339 340 341 342 343
	ret = debugfs_file_get(dentry);
	if (unlikely(ret))
		return ret;
	ret = simple_attr_write(file, buf, len, ppos);
	debugfs_file_put(dentry);
344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396
	return ret;
}
EXPORT_SYMBOL_GPL(debugfs_attr_write);

static struct dentry *debugfs_create_mode_unsafe(const char *name, umode_t mode,
					struct dentry *parent, void *value,
					const struct file_operations *fops,
					const struct file_operations *fops_ro,
					const struct file_operations *fops_wo)
{
	/* if there are no write bits set, make read only */
	if (!(mode & S_IWUGO))
		return debugfs_create_file_unsafe(name, mode, parent, value,
						fops_ro);
	/* if there are no read bits set, make write only */
	if (!(mode & S_IRUGO))
		return debugfs_create_file_unsafe(name, mode, parent, value,
						fops_wo);

	return debugfs_create_file_unsafe(name, mode, parent, value, fops);
}

static int debugfs_u8_set(void *data, u64 val)
{
	*(u8 *)data = val;
	return 0;
}
static int debugfs_u8_get(void *data, u64 *val)
{
	*val = *(u8 *)data;
	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");

/**
 * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 *
 * This function creates a file in debugfs with the given name that
 * contains the value of the variable @value.  If the @mode variable is so
 * set, it can be read from, and written to.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
397 398
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
399
 *
400 401
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441
 */
struct dentry *debugfs_create_u8(const char *name, umode_t mode,
				 struct dentry *parent, u8 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u8,
				   &fops_u8_ro, &fops_u8_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u8);

static int debugfs_u16_set(void *data, u64 val)
{
	*(u16 *)data = val;
	return 0;
}
static int debugfs_u16_get(void *data, u64 *val)
{
	*val = *(u16 *)data;
	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");

/**
 * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 *
 * This function creates a file in debugfs with the given name that
 * contains the value of the variable @value.  If the @mode variable is so
 * set, it can be read from, and written to.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
442 443
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
444
 *
445 446
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486
 */
struct dentry *debugfs_create_u16(const char *name, umode_t mode,
				  struct dentry *parent, u16 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u16,
				   &fops_u16_ro, &fops_u16_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u16);

static int debugfs_u32_set(void *data, u64 val)
{
	*(u32 *)data = val;
	return 0;
}
static int debugfs_u32_get(void *data, u64 *val)
{
	*val = *(u32 *)data;
	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");

/**
 * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 *
 * This function creates a file in debugfs with the given name that
 * contains the value of the variable @value.  If the @mode variable is so
 * set, it can be read from, and written to.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
487 488
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
489
 *
490 491
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532
 */
struct dentry *debugfs_create_u32(const char *name, umode_t mode,
				 struct dentry *parent, u32 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u32,
				   &fops_u32_ro, &fops_u32_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u32);

static int debugfs_u64_set(void *data, u64 val)
{
	*(u64 *)data = val;
	return 0;
}

static int debugfs_u64_get(void *data, u64 *val)
{
	*val = *(u64 *)data;
	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");

/**
 * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 *
 * This function creates a file in debugfs with the given name that
 * contains the value of the variable @value.  If the @mode variable is so
 * set, it can be read from, and written to.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
533 534
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
535
 *
536 537
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580
 */
struct dentry *debugfs_create_u64(const char *name, umode_t mode,
				 struct dentry *parent, u64 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_u64,
				   &fops_u64_ro, &fops_u64_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_u64);

static int debugfs_ulong_set(void *data, u64 val)
{
	*(unsigned long *)data = val;
	return 0;
}

static int debugfs_ulong_get(void *data, u64 *val)
{
	*val = *(unsigned long *)data;
	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong, debugfs_ulong_get, debugfs_ulong_set,
			"%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_ro, debugfs_ulong_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_ulong_wo, NULL, debugfs_ulong_set, "%llu\n");

/**
 * debugfs_create_ulong - create a debugfs file that is used to read and write
 * an unsigned long value.
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 *
 * This function creates a file in debugfs with the given name that
 * contains the value of the variable @value.  If the @mode variable is so
 * set, it can be read from, and written to.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
581 582
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
583
 *
584 585
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771
 */
struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
				    struct dentry *parent, unsigned long *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value,
					&fops_ulong, &fops_ulong_ro,
					&fops_ulong_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_ulong);

DEFINE_DEBUGFS_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");

DEFINE_DEBUGFS_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set,
			"0x%04llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");

DEFINE_DEBUGFS_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set,
			"0x%08llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");

DEFINE_DEBUGFS_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set,
			"0x%016llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_ro, debugfs_u64_get, NULL, "0x%016llx\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_x64_wo, NULL, debugfs_u64_set, "0x%016llx\n");

/*
 * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
 *
 * These functions are exactly the same as the above functions (but use a hex
 * output for the decimal challenged). For details look at the above unsigned
 * decimal functions.
 */

/**
 * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_x8(const char *name, umode_t mode,
				 struct dentry *parent, u8 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x8,
				   &fops_x8_ro, &fops_x8_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x8);

/**
 * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_x16(const char *name, umode_t mode,
				 struct dentry *parent, u16 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x16,
				   &fops_x16_ro, &fops_x16_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x16);

/**
 * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_x32(const char *name, umode_t mode,
				 struct dentry *parent, u32 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x32,
				   &fops_x32_ro, &fops_x32_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x32);

/**
 * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_x64(const char *name, umode_t mode,
				 struct dentry *parent, u64 *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_x64,
				   &fops_x64_ro, &fops_x64_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_x64);


static int debugfs_size_t_set(void *data, u64 val)
{
	*(size_t *)data = val;
	return 0;
}
static int debugfs_size_t_get(void *data, u64 *val)
{
	*val = *(size_t *)data;
	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
			"%llu\n"); /* %llu and %zu are more or less the same */
DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_ro, debugfs_size_t_get, NULL, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_size_t_wo, NULL, debugfs_size_t_set, "%llu\n");

/**
 * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
				     struct dentry *parent, size_t *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value,
					&fops_size_t, &fops_size_t_ro,
					&fops_size_t_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_size_t);

static int debugfs_atomic_t_set(void *data, u64 val)
{
	atomic_set((atomic_t *)data, val);
	return 0;
}
static int debugfs_atomic_t_get(void *data, u64 *val)
{
	*val = atomic_read((atomic_t *)data);
	return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
			debugfs_atomic_t_set, "%lld\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_ro, debugfs_atomic_t_get, NULL,
			"%lld\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_atomic_t_wo, NULL, debugfs_atomic_t_set,
			"%lld\n");

/**
 * debugfs_create_atomic_t - create a debugfs file that is used to read and
 * write an atomic_t value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 */
struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
				 struct dentry *parent, atomic_t *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value,
					&fops_atomic_t, &fops_atomic_t_ro,
					&fops_atomic_t_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_atomic_t);

ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
			       size_t count, loff_t *ppos)
{
	char buf[3];
	bool val;
772 773
	int r;
	struct dentry *dentry = F_DENTRY(file);
774

775 776
	r = debugfs_file_get(dentry);
	if (unlikely(r))
777
		return r;
778 779
	val = *(bool *)file->private_data;
	debugfs_file_put(dentry);
780 781 782 783 784 785 786 787 788 789 790 791 792 793 794

	if (val)
		buf[0] = 'Y';
	else
		buf[0] = 'N';
	buf[1] = '\n';
	buf[2] = 0x00;
	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}
EXPORT_SYMBOL_GPL(debugfs_read_file_bool);

ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
				size_t count, loff_t *ppos)
{
	bool bv;
795
	int r;
796
	bool *val = file->private_data;
797
	struct dentry *dentry = F_DENTRY(file);
798

799 800
	r = kstrtobool_from_user(user_buf, count, &bv);
	if (!r) {
801 802
		r = debugfs_file_get(dentry);
		if (unlikely(r))
803
			return r;
804 805
		*val = bv;
		debugfs_file_put(dentry);
806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847
	}

	return count;
}
EXPORT_SYMBOL_GPL(debugfs_write_file_bool);

static const struct file_operations fops_bool = {
	.read =		debugfs_read_file_bool,
	.write =	debugfs_write_file_bool,
	.open =		simple_open,
	.llseek =	default_llseek,
};

static const struct file_operations fops_bool_ro = {
	.read =		debugfs_read_file_bool,
	.open =		simple_open,
	.llseek =	default_llseek,
};

static const struct file_operations fops_bool_wo = {
	.write =	debugfs_write_file_bool,
	.open =		simple_open,
	.llseek =	default_llseek,
};

/**
 * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @value: a pointer to the variable that the file should read to and write
 *         from.
 *
 * This function creates a file in debugfs with the given name that
 * contains the value of the variable @value.  If the @mode variable is so
 * set, it can be read from, and written to.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
848 849
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
850
 *
851 852
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
853 854 855 856 857 858 859 860 861 862 863 864 865
 */
struct dentry *debugfs_create_bool(const char *name, umode_t mode,
				   struct dentry *parent, bool *value)
{
	return debugfs_create_mode_unsafe(name, mode, parent, value, &fops_bool,
				   &fops_bool_ro, &fops_bool_wo);
}
EXPORT_SYMBOL_GPL(debugfs_create_bool);

static ssize_t read_file_blob(struct file *file, char __user *user_buf,
			      size_t count, loff_t *ppos)
{
	struct debugfs_blob_wrapper *blob = file->private_data;
866
	struct dentry *dentry = F_DENTRY(file);
867 868
	ssize_t r;

869 870 871 872 873 874
	r = debugfs_file_get(dentry);
	if (unlikely(r))
		return r;
	r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
				blob->size);
	debugfs_file_put(dentry);
875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900
	return r;
}

static const struct file_operations fops_blob = {
	.read =		read_file_blob,
	.open =		simple_open,
	.llseek =	default_llseek,
};

/**
 * debugfs_create_blob - create a debugfs file that is used to read a binary blob
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
 *        to the blob data and the size of the data.
 *
 * This function creates a file in debugfs with the given name that exports
 * @blob->data as a binary blob. If the @mode variable is so set it can be
 * read from. Writing is not supported.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
901 902
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
903
 *
904 905
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000
 */
struct dentry *debugfs_create_blob(const char *name, umode_t mode,
				   struct dentry *parent,
				   struct debugfs_blob_wrapper *blob)
{
	return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob);
}
EXPORT_SYMBOL_GPL(debugfs_create_blob);

struct array_data {
	void *array;
	u32 elements;
};

static size_t u32_format_array(char *buf, size_t bufsize,
			       u32 *array, int array_size)
{
	size_t ret = 0;

	while (--array_size >= 0) {
		size_t len;
		char term = array_size ? ' ' : '\n';

		len = snprintf(buf, bufsize, "%u%c", *array++, term);
		ret += len;

		buf += len;
		bufsize -= len;
	}
	return ret;
}

static int u32_array_open(struct inode *inode, struct file *file)
{
	struct array_data *data = inode->i_private;
	int size, elements = data->elements;
	char *buf;

	/*
	 * Max size:
	 *  - 10 digits + ' '/'\n' = 11 bytes per number
	 *  - terminating NUL character
	 */
	size = elements*11;
	buf = kmalloc(size+1, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	buf[size] = 0;

	file->private_data = buf;
	u32_format_array(buf, size, data->array, data->elements);

	return nonseekable_open(inode, file);
}

static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
			      loff_t *ppos)
{
	size_t size = strlen(file->private_data);

	return simple_read_from_buffer(buf, len, ppos,
					file->private_data, size);
}

static int u32_array_release(struct inode *inode, struct file *file)
{
	kfree(file->private_data);

	return 0;
}

static const struct file_operations u32_array_fops = {
	.owner	 = THIS_MODULE,
	.open	 = u32_array_open,
	.release = u32_array_release,
	.read	 = u32_array_read,
	.llseek  = no_llseek,
};

/**
 * debugfs_create_u32_array - create a debugfs file that is used to read u32
 * array.
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have.
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @array: u32 array that provides data.
 * @elements: total number of elements in the array.
 *
 * This function creates a file in debugfs with the given name that exports
 * @array as data. If the @mode variable is so set it can be read from.
 * Writing is not supported. Seek within the file is also not supported.
 * Once array is created its size can not be changed.
 */
1001 1002
void debugfs_create_u32_array(const char *name, umode_t mode,
			      struct dentry *parent, u32 *array, u32 elements)
1003 1004 1005 1006
{
	struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);

	if (data == NULL)
1007
		return;
1008 1009 1010 1011

	data->array = array;
	data->elements = elements;

1012
	debugfs_create_file_unsafe(name, mode, parent, data, &u32_array_fops);
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092
}
EXPORT_SYMBOL_GPL(debugfs_create_u32_array);

#ifdef CONFIG_HAS_IOMEM

/*
 * The regset32 stuff is used to print 32-bit registers using the
 * seq_file utilities. We offer printing a register set in an already-opened
 * sequential file or create a debugfs file that only prints a regset32.
 */

/**
 * debugfs_print_regs32 - use seq_print to describe a set of registers
 * @s: the seq_file structure being used to generate output
 * @regs: an array if struct debugfs_reg32 structures
 * @nregs: the length of the above array
 * @base: the base address to be used in reading the registers
 * @prefix: a string to be prefixed to every output line
 *
 * This function outputs a text block describing the current values of
 * some 32-bit hardware registers. It is meant to be used within debugfs
 * files based on seq_file that need to show registers, intermixed with other
 * information. The prefix argument may be used to specify a leading string,
 * because some peripherals have several blocks of identical registers,
 * for example configuration of dma channels
 */
void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
			  int nregs, void __iomem *base, char *prefix)
{
	int i;

	for (i = 0; i < nregs; i++, regs++) {
		if (prefix)
			seq_printf(s, "%s", prefix);
		seq_printf(s, "%s = 0x%08x\n", regs->name,
			   readl(base + regs->offset));
		if (seq_has_overflowed(s))
			break;
	}
}
EXPORT_SYMBOL_GPL(debugfs_print_regs32);

static int debugfs_show_regset32(struct seq_file *s, void *data)
{
	struct debugfs_regset32 *regset = s->private;

	debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
	return 0;
}

static int debugfs_open_regset32(struct inode *inode, struct file *file)
{
	return single_open(file, debugfs_show_regset32, inode->i_private);
}

static const struct file_operations fops_regset32 = {
	.open =		debugfs_open_regset32,
	.read =		seq_read,
	.llseek =	seq_lseek,
	.release =	single_release,
};

/**
 * debugfs_create_regset32 - create a debugfs file that returns register values
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @regset: a pointer to a struct debugfs_regset32, which contains a pointer
 *          to an array of register definitions, the array size and the base
 *          address where the register bank is to be found.
 *
 * This function creates a file in debugfs with the given name that reports
 * the names and values of a set of 32-bit registers. If the @mode variable
 * is so set it can be read from. Writing is not supported.
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
1093 1094
 * you are responsible here.)  If an error occurs, %ERR_PTR(-ERROR) will be
 * returned.
1095
 *
1096 1097
 * If debugfs is not enabled in the kernel, the value %ERR_PTR(-ENODEV) will
 * be returned.
1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160
 */
struct dentry *debugfs_create_regset32(const char *name, umode_t mode,
				       struct dentry *parent,
				       struct debugfs_regset32 *regset)
{
	return debugfs_create_file(name, mode, parent, regset, &fops_regset32);
}
EXPORT_SYMBOL_GPL(debugfs_create_regset32);

#endif /* CONFIG_HAS_IOMEM */

struct debugfs_devm_entry {
	int (*read)(struct seq_file *seq, void *data);
	struct device *dev;
};

static int debugfs_devm_entry_open(struct inode *inode, struct file *f)
{
	struct debugfs_devm_entry *entry = inode->i_private;

	return single_open(f, entry->read, entry->dev);
}

static const struct file_operations debugfs_devm_entry_ops = {
	.owner = THIS_MODULE,
	.open = debugfs_devm_entry_open,
	.release = single_release,
	.read = seq_read,
	.llseek = seq_lseek
};

/**
 * debugfs_create_devm_seqfile - create a debugfs file that is bound to device.
 *
 * @dev: device related to this debugfs file.
 * @name: name of the debugfs file.
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *	directory dentry if set.  If this parameter is %NULL, then the
 *	file will be created in the root of the debugfs filesystem.
 * @read_fn: function pointer called to print the seq_file content.
 */
struct dentry *debugfs_create_devm_seqfile(struct device *dev, const char *name,
					   struct dentry *parent,
					   int (*read_fn)(struct seq_file *s,
							  void *data))
{
	struct debugfs_devm_entry *entry;

	if (IS_ERR(parent))
		return ERR_PTR(-ENOENT);

	entry = devm_kzalloc(dev, sizeof(*entry), GFP_KERNEL);
	if (!entry)
		return ERR_PTR(-ENOMEM);

	entry->read = read_fn;
	entry->dev = dev;

	return debugfs_create_file(name, S_IRUGO, parent, entry,
				   &debugfs_devm_entry_ops);
}
EXPORT_SYMBOL_GPL(debugfs_create_devm_seqfile);