xref: /linux/kernel/sysctl.c (revision dbcedec3a31119d7594baacc743300d127c99c56)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * sysctl.c: General linux system control interface
4  *
5  * Begun 24 March 1995, Stephen Tweedie
6  * Added /proc support, Dec 1995
7  * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
8  * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
9  * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
10  * Dynamic registration fixes, Stephen Tweedie.
11  * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
12  * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
13  *  Horn.
14  * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
15  * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
16  * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
17  *  Wendling.
18  * The list_for_each() macro wasn't appropriate for the sysctl loop.
19  *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
20  */
21 
22 #include <linux/module.h>
23 #include <linux/mm.h>
24 #include <linux/swap.h>
25 #include <linux/slab.h>
26 #include <linux/sysctl.h>
27 #include <linux/bitmap.h>
28 #include <linux/signal.h>
29 #include <linux/panic.h>
30 #include <linux/printk.h>
31 #include <linux/proc_fs.h>
32 #include <linux/security.h>
33 #include <linux/ctype.h>
34 #include <linux/kmemleak.h>
35 #include <linux/filter.h>
36 #include <linux/fs.h>
37 #include <linux/init.h>
38 #include <linux/kernel.h>
39 #include <linux/kobject.h>
40 #include <linux/net.h>
41 #include <linux/sysrq.h>
42 #include <linux/highuid.h>
43 #include <linux/writeback.h>
44 #include <linux/ratelimit.h>
45 #include <linux/hugetlb.h>
46 #include <linux/initrd.h>
47 #include <linux/key.h>
48 #include <linux/times.h>
49 #include <linux/limits.h>
50 #include <linux/dcache.h>
51 #include <linux/syscalls.h>
52 #include <linux/vmstat.h>
53 #include <linux/nfs_fs.h>
54 #include <linux/acpi.h>
55 #include <linux/reboot.h>
56 #include <linux/ftrace.h>
57 #include <linux/perf_event.h>
58 #include <linux/oom.h>
59 #include <linux/kmod.h>
60 #include <linux/capability.h>
61 #include <linux/binfmts.h>
62 #include <linux/sched/sysctl.h>
63 #include <linux/mount.h>
64 #include <linux/userfaultfd_k.h>
65 #include <linux/pid.h>
66 
67 #include "../lib/kstrtox.h"
68 
69 #include <linux/uaccess.h>
70 #include <asm/processor.h>
71 
72 #ifdef CONFIG_X86
73 #include <asm/nmi.h>
74 #include <asm/stacktrace.h>
75 #include <asm/io.h>
76 #endif
77 #ifdef CONFIG_SPARC
78 #include <asm/setup.h>
79 #endif
80 #ifdef CONFIG_RT_MUTEXES
81 #include <linux/rtmutex.h>
82 #endif
83 
84 /* shared constants to be used in various sysctls */
85 const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 };
86 EXPORT_SYMBOL(sysctl_vals);
87 
88 const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX };
89 EXPORT_SYMBOL_GPL(sysctl_long_vals);
90 
91 #if defined(CONFIG_SYSCTL)
92 
93 /* Constants used for minimum and maximum */
94 
95 #ifdef CONFIG_PERF_EVENTS
96 static const int six_hundred_forty_kb = 640 * 1024;
97 #endif
98 
99 
100 static const int ngroups_max = NGROUPS_MAX;
101 static const int cap_last_cap = CAP_LAST_CAP;
102 
103 #ifdef CONFIG_PROC_SYSCTL
104 
105 /**
106  * enum sysctl_writes_mode - supported sysctl write modes
107  *
108  * @SYSCTL_WRITES_LEGACY: each write syscall must fully contain the sysctl value
109  *	to be written, and multiple writes on the same sysctl file descriptor
110  *	will rewrite the sysctl value, regardless of file position. No warning
111  *	is issued when the initial position is not 0.
112  * @SYSCTL_WRITES_WARN: same as above but warn when the initial file position is
113  *	not 0.
114  * @SYSCTL_WRITES_STRICT: writes to numeric sysctl entries must always be at
115  *	file position 0 and the value must be fully contained in the buffer
116  *	sent to the write syscall. If dealing with strings respect the file
117  *	position, but restrict this to the max length of the buffer, anything
118  *	passed the max length will be ignored. Multiple writes will append
119  *	to the buffer.
120  *
121  * These write modes control how current file position affects the behavior of
122  * updating sysctl values through the proc interface on each write.
123  */
124 enum sysctl_writes_mode {
125 	SYSCTL_WRITES_LEGACY		= -1,
126 	SYSCTL_WRITES_WARN		= 0,
127 	SYSCTL_WRITES_STRICT		= 1,
128 };
129 
130 static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
131 #endif /* CONFIG_PROC_SYSCTL */
132 
133 #if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
134     defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
135 int sysctl_legacy_va_layout;
136 #endif
137 
138 #endif /* CONFIG_SYSCTL */
139 
140 /*
141  * /proc/sys support
142  */
143 
144 #ifdef CONFIG_PROC_SYSCTL
145 
146 static int _proc_do_string(char *data, int maxlen, int write,
147 		char *buffer, size_t *lenp, loff_t *ppos)
148 {
149 	size_t len;
150 	char c, *p;
151 
152 	if (!data || !maxlen || !*lenp) {
153 		*lenp = 0;
154 		return 0;
155 	}
156 
157 	if (write) {
158 		if (sysctl_writes_strict == SYSCTL_WRITES_STRICT) {
159 			/* Only continue writes not past the end of buffer. */
160 			len = strlen(data);
161 			if (len > maxlen - 1)
162 				len = maxlen - 1;
163 
164 			if (*ppos > len)
165 				return 0;
166 			len = *ppos;
167 		} else {
168 			/* Start writing from beginning of buffer. */
169 			len = 0;
170 		}
171 
172 		*ppos += *lenp;
173 		p = buffer;
174 		while ((p - buffer) < *lenp && len < maxlen - 1) {
175 			c = *(p++);
176 			if (c == 0 || c == '\n')
177 				break;
178 			data[len++] = c;
179 		}
180 		data[len] = 0;
181 	} else {
182 		len = strlen(data);
183 		if (len > maxlen)
184 			len = maxlen;
185 
186 		if (*ppos > len) {
187 			*lenp = 0;
188 			return 0;
189 		}
190 
191 		data += *ppos;
192 		len  -= *ppos;
193 
194 		if (len > *lenp)
195 			len = *lenp;
196 		if (len)
197 			memcpy(buffer, data, len);
198 		if (len < *lenp) {
199 			buffer[len] = '\n';
200 			len++;
201 		}
202 		*lenp = len;
203 		*ppos += len;
204 	}
205 	return 0;
206 }
207 
208 static void warn_sysctl_write(struct ctl_table *table)
209 {
210 	pr_warn_once("%s wrote to %s when file position was not 0!\n"
211 		"This will not be supported in the future. To silence this\n"
212 		"warning, set kernel.sysctl_writes_strict = -1\n",
213 		current->comm, table->procname);
214 }
215 
216 /**
217  * proc_first_pos_non_zero_ignore - check if first position is allowed
218  * @ppos: file position
219  * @table: the sysctl table
220  *
221  * Returns true if the first position is non-zero and the sysctl_writes_strict
222  * mode indicates this is not allowed for numeric input types. String proc
223  * handlers can ignore the return value.
224  */
225 static bool proc_first_pos_non_zero_ignore(loff_t *ppos,
226 					   struct ctl_table *table)
227 {
228 	if (!*ppos)
229 		return false;
230 
231 	switch (sysctl_writes_strict) {
232 	case SYSCTL_WRITES_STRICT:
233 		return true;
234 	case SYSCTL_WRITES_WARN:
235 		warn_sysctl_write(table);
236 		return false;
237 	default:
238 		return false;
239 	}
240 }
241 
242 /**
243  * proc_dostring - read a string sysctl
244  * @table: the sysctl table
245  * @write: %TRUE if this is a write to the sysctl file
246  * @buffer: the user buffer
247  * @lenp: the size of the user buffer
248  * @ppos: file position
249  *
250  * Reads/writes a string from/to the user buffer. If the kernel
251  * buffer provided is not large enough to hold the string, the
252  * string is truncated. The copied string is %NULL-terminated.
253  * If the string is being read by the user process, it is copied
254  * and a newline '\n' is added. It is truncated if the buffer is
255  * not large enough.
256  *
257  * Returns 0 on success.
258  */
259 int proc_dostring(struct ctl_table *table, int write,
260 		  void *buffer, size_t *lenp, loff_t *ppos)
261 {
262 	if (write)
263 		proc_first_pos_non_zero_ignore(ppos, table);
264 
265 	return _proc_do_string(table->data, table->maxlen, write, buffer, lenp,
266 			ppos);
267 }
268 
269 static void proc_skip_spaces(char **buf, size_t *size)
270 {
271 	while (*size) {
272 		if (!isspace(**buf))
273 			break;
274 		(*size)--;
275 		(*buf)++;
276 	}
277 }
278 
279 static void proc_skip_char(char **buf, size_t *size, const char v)
280 {
281 	while (*size) {
282 		if (**buf != v)
283 			break;
284 		(*size)--;
285 		(*buf)++;
286 	}
287 }
288 
289 /**
290  * strtoul_lenient - parse an ASCII formatted integer from a buffer and only
291  *                   fail on overflow
292  *
293  * @cp: kernel buffer containing the string to parse
294  * @endp: pointer to store the trailing characters
295  * @base: the base to use
296  * @res: where the parsed integer will be stored
297  *
298  * In case of success 0 is returned and @res will contain the parsed integer,
299  * @endp will hold any trailing characters.
300  * This function will fail the parse on overflow. If there wasn't an overflow
301  * the function will defer the decision what characters count as invalid to the
302  * caller.
303  */
304 static int strtoul_lenient(const char *cp, char **endp, unsigned int base,
305 			   unsigned long *res)
306 {
307 	unsigned long long result;
308 	unsigned int rv;
309 
310 	cp = _parse_integer_fixup_radix(cp, &base);
311 	rv = _parse_integer(cp, base, &result);
312 	if ((rv & KSTRTOX_OVERFLOW) || (result != (unsigned long)result))
313 		return -ERANGE;
314 
315 	cp += rv;
316 
317 	if (endp)
318 		*endp = (char *)cp;
319 
320 	*res = (unsigned long)result;
321 	return 0;
322 }
323 
324 #define TMPBUFLEN 22
325 /**
326  * proc_get_long - reads an ASCII formatted integer from a user buffer
327  *
328  * @buf: a kernel buffer
329  * @size: size of the kernel buffer
330  * @val: this is where the number will be stored
331  * @neg: set to %TRUE if number is negative
332  * @perm_tr: a vector which contains the allowed trailers
333  * @perm_tr_len: size of the perm_tr vector
334  * @tr: pointer to store the trailer character
335  *
336  * In case of success %0 is returned and @buf and @size are updated with
337  * the amount of bytes read. If @tr is non-NULL and a trailing
338  * character exists (size is non-zero after returning from this
339  * function), @tr is updated with the trailing character.
340  */
341 static int proc_get_long(char **buf, size_t *size,
342 			  unsigned long *val, bool *neg,
343 			  const char *perm_tr, unsigned perm_tr_len, char *tr)
344 {
345 	char *p, tmp[TMPBUFLEN];
346 	ssize_t len = *size;
347 
348 	if (len <= 0)
349 		return -EINVAL;
350 
351 	if (len > TMPBUFLEN - 1)
352 		len = TMPBUFLEN - 1;
353 
354 	memcpy(tmp, *buf, len);
355 
356 	tmp[len] = 0;
357 	p = tmp;
358 	if (*p == '-' && *size > 1) {
359 		*neg = true;
360 		p++;
361 	} else
362 		*neg = false;
363 	if (!isdigit(*p))
364 		return -EINVAL;
365 
366 	if (strtoul_lenient(p, &p, 0, val))
367 		return -EINVAL;
368 
369 	len = p - tmp;
370 
371 	/* We don't know if the next char is whitespace thus we may accept
372 	 * invalid integers (e.g. 1234...a) or two integers instead of one
373 	 * (e.g. 123...1). So lets not allow such large numbers. */
374 	if (len == TMPBUFLEN - 1)
375 		return -EINVAL;
376 
377 	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
378 		return -EINVAL;
379 
380 	if (tr && (len < *size))
381 		*tr = *p;
382 
383 	*buf += len;
384 	*size -= len;
385 
386 	return 0;
387 }
388 
389 /**
390  * proc_put_long - converts an integer to a decimal ASCII formatted string
391  *
392  * @buf: the user buffer
393  * @size: the size of the user buffer
394  * @val: the integer to be converted
395  * @neg: sign of the number, %TRUE for negative
396  *
397  * In case of success @buf and @size are updated with the amount of bytes
398  * written.
399  */
400 static void proc_put_long(void **buf, size_t *size, unsigned long val, bool neg)
401 {
402 	int len;
403 	char tmp[TMPBUFLEN], *p = tmp;
404 
405 	sprintf(p, "%s%lu", neg ? "-" : "", val);
406 	len = strlen(tmp);
407 	if (len > *size)
408 		len = *size;
409 	memcpy(*buf, tmp, len);
410 	*size -= len;
411 	*buf += len;
412 }
413 #undef TMPBUFLEN
414 
415 static void proc_put_char(void **buf, size_t *size, char c)
416 {
417 	if (*size) {
418 		char **buffer = (char **)buf;
419 		**buffer = c;
420 
421 		(*size)--;
422 		(*buffer)++;
423 		*buf = *buffer;
424 	}
425 }
426 
427 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
428 				 int *valp,
429 				 int write, void *data)
430 {
431 	if (write) {
432 		if (*negp) {
433 			if (*lvalp > (unsigned long) INT_MAX + 1)
434 				return -EINVAL;
435 			WRITE_ONCE(*valp, -*lvalp);
436 		} else {
437 			if (*lvalp > (unsigned long) INT_MAX)
438 				return -EINVAL;
439 			WRITE_ONCE(*valp, *lvalp);
440 		}
441 	} else {
442 		int val = READ_ONCE(*valp);
443 		if (val < 0) {
444 			*negp = true;
445 			*lvalp = -(unsigned long)val;
446 		} else {
447 			*negp = false;
448 			*lvalp = (unsigned long)val;
449 		}
450 	}
451 	return 0;
452 }
453 
454 static int do_proc_douintvec_conv(unsigned long *lvalp,
455 				  unsigned int *valp,
456 				  int write, void *data)
457 {
458 	if (write) {
459 		if (*lvalp > UINT_MAX)
460 			return -EINVAL;
461 		WRITE_ONCE(*valp, *lvalp);
462 	} else {
463 		unsigned int val = READ_ONCE(*valp);
464 		*lvalp = (unsigned long)val;
465 	}
466 	return 0;
467 }
468 
469 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
470 
471 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
472 		  int write, void *buffer,
473 		  size_t *lenp, loff_t *ppos,
474 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
475 			      int write, void *data),
476 		  void *data)
477 {
478 	int *i, vleft, first = 1, err = 0;
479 	size_t left;
480 	char *p;
481 
482 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
483 		*lenp = 0;
484 		return 0;
485 	}
486 
487 	i = (int *) tbl_data;
488 	vleft = table->maxlen / sizeof(*i);
489 	left = *lenp;
490 
491 	if (!conv)
492 		conv = do_proc_dointvec_conv;
493 
494 	if (write) {
495 		if (proc_first_pos_non_zero_ignore(ppos, table))
496 			goto out;
497 
498 		if (left > PAGE_SIZE - 1)
499 			left = PAGE_SIZE - 1;
500 		p = buffer;
501 	}
502 
503 	for (; left && vleft--; i++, first=0) {
504 		unsigned long lval;
505 		bool neg;
506 
507 		if (write) {
508 			proc_skip_spaces(&p, &left);
509 
510 			if (!left)
511 				break;
512 			err = proc_get_long(&p, &left, &lval, &neg,
513 					     proc_wspace_sep,
514 					     sizeof(proc_wspace_sep), NULL);
515 			if (err)
516 				break;
517 			if (conv(&neg, &lval, i, 1, data)) {
518 				err = -EINVAL;
519 				break;
520 			}
521 		} else {
522 			if (conv(&neg, &lval, i, 0, data)) {
523 				err = -EINVAL;
524 				break;
525 			}
526 			if (!first)
527 				proc_put_char(&buffer, &left, '\t');
528 			proc_put_long(&buffer, &left, lval, neg);
529 		}
530 	}
531 
532 	if (!write && !first && left && !err)
533 		proc_put_char(&buffer, &left, '\n');
534 	if (write && !err && left)
535 		proc_skip_spaces(&p, &left);
536 	if (write && first)
537 		return err ? : -EINVAL;
538 	*lenp -= left;
539 out:
540 	*ppos += *lenp;
541 	return err;
542 }
543 
544 static int do_proc_dointvec(struct ctl_table *table, int write,
545 		  void *buffer, size_t *lenp, loff_t *ppos,
546 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
547 			      int write, void *data),
548 		  void *data)
549 {
550 	return __do_proc_dointvec(table->data, table, write,
551 			buffer, lenp, ppos, conv, data);
552 }
553 
554 static int do_proc_douintvec_w(unsigned int *tbl_data,
555 			       struct ctl_table *table,
556 			       void *buffer,
557 			       size_t *lenp, loff_t *ppos,
558 			       int (*conv)(unsigned long *lvalp,
559 					   unsigned int *valp,
560 					   int write, void *data),
561 			       void *data)
562 {
563 	unsigned long lval;
564 	int err = 0;
565 	size_t left;
566 	bool neg;
567 	char *p = buffer;
568 
569 	left = *lenp;
570 
571 	if (proc_first_pos_non_zero_ignore(ppos, table))
572 		goto bail_early;
573 
574 	if (left > PAGE_SIZE - 1)
575 		left = PAGE_SIZE - 1;
576 
577 	proc_skip_spaces(&p, &left);
578 	if (!left) {
579 		err = -EINVAL;
580 		goto out_free;
581 	}
582 
583 	err = proc_get_long(&p, &left, &lval, &neg,
584 			     proc_wspace_sep,
585 			     sizeof(proc_wspace_sep), NULL);
586 	if (err || neg) {
587 		err = -EINVAL;
588 		goto out_free;
589 	}
590 
591 	if (conv(&lval, tbl_data, 1, data)) {
592 		err = -EINVAL;
593 		goto out_free;
594 	}
595 
596 	if (!err && left)
597 		proc_skip_spaces(&p, &left);
598 
599 out_free:
600 	if (err)
601 		return -EINVAL;
602 
603 	return 0;
604 
605 	/* This is in keeping with old __do_proc_dointvec() */
606 bail_early:
607 	*ppos += *lenp;
608 	return err;
609 }
610 
611 static int do_proc_douintvec_r(unsigned int *tbl_data, void *buffer,
612 			       size_t *lenp, loff_t *ppos,
613 			       int (*conv)(unsigned long *lvalp,
614 					   unsigned int *valp,
615 					   int write, void *data),
616 			       void *data)
617 {
618 	unsigned long lval;
619 	int err = 0;
620 	size_t left;
621 
622 	left = *lenp;
623 
624 	if (conv(&lval, tbl_data, 0, data)) {
625 		err = -EINVAL;
626 		goto out;
627 	}
628 
629 	proc_put_long(&buffer, &left, lval, false);
630 	if (!left)
631 		goto out;
632 
633 	proc_put_char(&buffer, &left, '\n');
634 
635 out:
636 	*lenp -= left;
637 	*ppos += *lenp;
638 
639 	return err;
640 }
641 
642 static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table,
643 			       int write, void *buffer,
644 			       size_t *lenp, loff_t *ppos,
645 			       int (*conv)(unsigned long *lvalp,
646 					   unsigned int *valp,
647 					   int write, void *data),
648 			       void *data)
649 {
650 	unsigned int *i, vleft;
651 
652 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
653 		*lenp = 0;
654 		return 0;
655 	}
656 
657 	i = (unsigned int *) tbl_data;
658 	vleft = table->maxlen / sizeof(*i);
659 
660 	/*
661 	 * Arrays are not supported, keep this simple. *Do not* add
662 	 * support for them.
663 	 */
664 	if (vleft != 1) {
665 		*lenp = 0;
666 		return -EINVAL;
667 	}
668 
669 	if (!conv)
670 		conv = do_proc_douintvec_conv;
671 
672 	if (write)
673 		return do_proc_douintvec_w(i, table, buffer, lenp, ppos,
674 					   conv, data);
675 	return do_proc_douintvec_r(i, buffer, lenp, ppos, conv, data);
676 }
677 
678 int do_proc_douintvec(struct ctl_table *table, int write,
679 		      void *buffer, size_t *lenp, loff_t *ppos,
680 		      int (*conv)(unsigned long *lvalp,
681 				  unsigned int *valp,
682 				  int write, void *data),
683 		      void *data)
684 {
685 	return __do_proc_douintvec(table->data, table, write,
686 				   buffer, lenp, ppos, conv, data);
687 }
688 
689 /**
690  * proc_dobool - read/write a bool
691  * @table: the sysctl table
692  * @write: %TRUE if this is a write to the sysctl file
693  * @buffer: the user buffer
694  * @lenp: the size of the user buffer
695  * @ppos: file position
696  *
697  * Reads/writes one integer value from/to the user buffer,
698  * treated as an ASCII string.
699  *
700  * table->data must point to a bool variable and table->maxlen must
701  * be sizeof(bool).
702  *
703  * Returns 0 on success.
704  */
705 int proc_dobool(struct ctl_table *table, int write, void *buffer,
706 		size_t *lenp, loff_t *ppos)
707 {
708 	struct ctl_table tmp;
709 	bool *data = table->data;
710 	int res, val;
711 
712 	/* Do not support arrays yet. */
713 	if (table->maxlen != sizeof(bool))
714 		return -EINVAL;
715 
716 	tmp = *table;
717 	tmp.maxlen = sizeof(val);
718 	tmp.data = &val;
719 
720 	val = READ_ONCE(*data);
721 	res = proc_dointvec(&tmp, write, buffer, lenp, ppos);
722 	if (res)
723 		return res;
724 	if (write)
725 		WRITE_ONCE(*data, val);
726 	return 0;
727 }
728 
729 /**
730  * proc_dointvec - read a vector of integers
731  * @table: the sysctl table
732  * @write: %TRUE if this is a write to the sysctl file
733  * @buffer: the user buffer
734  * @lenp: the size of the user buffer
735  * @ppos: file position
736  *
737  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
738  * values from/to the user buffer, treated as an ASCII string.
739  *
740  * Returns 0 on success.
741  */
742 int proc_dointvec(struct ctl_table *table, int write, void *buffer,
743 		  size_t *lenp, loff_t *ppos)
744 {
745 	return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL);
746 }
747 
748 /**
749  * proc_douintvec - read a vector of unsigned integers
750  * @table: the sysctl table
751  * @write: %TRUE if this is a write to the sysctl file
752  * @buffer: the user buffer
753  * @lenp: the size of the user buffer
754  * @ppos: file position
755  *
756  * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
757  * values from/to the user buffer, treated as an ASCII string.
758  *
759  * Returns 0 on success.
760  */
761 int proc_douintvec(struct ctl_table *table, int write, void *buffer,
762 		size_t *lenp, loff_t *ppos)
763 {
764 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
765 				 do_proc_douintvec_conv, NULL);
766 }
767 
768 /*
769  * Taint values can only be increased
770  * This means we can safely use a temporary.
771  */
772 static int proc_taint(struct ctl_table *table, int write,
773 			       void *buffer, size_t *lenp, loff_t *ppos)
774 {
775 	struct ctl_table t;
776 	unsigned long tmptaint = get_taint();
777 	int err;
778 
779 	if (write && !capable(CAP_SYS_ADMIN))
780 		return -EPERM;
781 
782 	t = *table;
783 	t.data = &tmptaint;
784 	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
785 	if (err < 0)
786 		return err;
787 
788 	if (write) {
789 		int i;
790 
791 		/*
792 		 * If we are relying on panic_on_taint not producing
793 		 * false positives due to userspace input, bail out
794 		 * before setting the requested taint flags.
795 		 */
796 		if (panic_on_taint_nousertaint && (tmptaint & panic_on_taint))
797 			return -EINVAL;
798 
799 		/*
800 		 * Poor man's atomic or. Not worth adding a primitive
801 		 * to everyone's atomic.h for this
802 		 */
803 		for (i = 0; i < TAINT_FLAGS_COUNT; i++)
804 			if ((1UL << i) & tmptaint)
805 				add_taint(i, LOCKDEP_STILL_OK);
806 	}
807 
808 	return err;
809 }
810 
811 /**
812  * struct do_proc_dointvec_minmax_conv_param - proc_dointvec_minmax() range checking structure
813  * @min: pointer to minimum allowable value
814  * @max: pointer to maximum allowable value
815  *
816  * The do_proc_dointvec_minmax_conv_param structure provides the
817  * minimum and maximum values for doing range checking for those sysctl
818  * parameters that use the proc_dointvec_minmax() handler.
819  */
820 struct do_proc_dointvec_minmax_conv_param {
821 	int *min;
822 	int *max;
823 };
824 
825 static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
826 					int *valp,
827 					int write, void *data)
828 {
829 	int tmp, ret;
830 	struct do_proc_dointvec_minmax_conv_param *param = data;
831 	/*
832 	 * If writing, first do so via a temporary local int so we can
833 	 * bounds-check it before touching *valp.
834 	 */
835 	int *ip = write ? &tmp : valp;
836 
837 	ret = do_proc_dointvec_conv(negp, lvalp, ip, write, data);
838 	if (ret)
839 		return ret;
840 
841 	if (write) {
842 		if ((param->min && *param->min > tmp) ||
843 		    (param->max && *param->max < tmp))
844 			return -EINVAL;
845 		WRITE_ONCE(*valp, tmp);
846 	}
847 
848 	return 0;
849 }
850 
851 /**
852  * proc_dointvec_minmax - read a vector of integers with min/max values
853  * @table: the sysctl table
854  * @write: %TRUE if this is a write to the sysctl file
855  * @buffer: the user buffer
856  * @lenp: the size of the user buffer
857  * @ppos: file position
858  *
859  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
860  * values from/to the user buffer, treated as an ASCII string.
861  *
862  * This routine will ensure the values are within the range specified by
863  * table->extra1 (min) and table->extra2 (max).
864  *
865  * Returns 0 on success or -EINVAL on write when the range check fails.
866  */
867 int proc_dointvec_minmax(struct ctl_table *table, int write,
868 		  void *buffer, size_t *lenp, loff_t *ppos)
869 {
870 	struct do_proc_dointvec_minmax_conv_param param = {
871 		.min = (int *) table->extra1,
872 		.max = (int *) table->extra2,
873 	};
874 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
875 				do_proc_dointvec_minmax_conv, &param);
876 }
877 
878 /**
879  * struct do_proc_douintvec_minmax_conv_param - proc_douintvec_minmax() range checking structure
880  * @min: pointer to minimum allowable value
881  * @max: pointer to maximum allowable value
882  *
883  * The do_proc_douintvec_minmax_conv_param structure provides the
884  * minimum and maximum values for doing range checking for those sysctl
885  * parameters that use the proc_douintvec_minmax() handler.
886  */
887 struct do_proc_douintvec_minmax_conv_param {
888 	unsigned int *min;
889 	unsigned int *max;
890 };
891 
892 static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
893 					 unsigned int *valp,
894 					 int write, void *data)
895 {
896 	int ret;
897 	unsigned int tmp;
898 	struct do_proc_douintvec_minmax_conv_param *param = data;
899 	/* write via temporary local uint for bounds-checking */
900 	unsigned int *up = write ? &tmp : valp;
901 
902 	ret = do_proc_douintvec_conv(lvalp, up, write, data);
903 	if (ret)
904 		return ret;
905 
906 	if (write) {
907 		if ((param->min && *param->min > tmp) ||
908 		    (param->max && *param->max < tmp))
909 			return -ERANGE;
910 
911 		WRITE_ONCE(*valp, tmp);
912 	}
913 
914 	return 0;
915 }
916 
917 /**
918  * proc_douintvec_minmax - read a vector of unsigned ints with min/max values
919  * @table: the sysctl table
920  * @write: %TRUE if this is a write to the sysctl file
921  * @buffer: the user buffer
922  * @lenp: the size of the user buffer
923  * @ppos: file position
924  *
925  * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
926  * values from/to the user buffer, treated as an ASCII string. Negative
927  * strings are not allowed.
928  *
929  * This routine will ensure the values are within the range specified by
930  * table->extra1 (min) and table->extra2 (max). There is a final sanity
931  * check for UINT_MAX to avoid having to support wrap around uses from
932  * userspace.
933  *
934  * Returns 0 on success or -ERANGE on write when the range check fails.
935  */
936 int proc_douintvec_minmax(struct ctl_table *table, int write,
937 			  void *buffer, size_t *lenp, loff_t *ppos)
938 {
939 	struct do_proc_douintvec_minmax_conv_param param = {
940 		.min = (unsigned int *) table->extra1,
941 		.max = (unsigned int *) table->extra2,
942 	};
943 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
944 				 do_proc_douintvec_minmax_conv, &param);
945 }
946 
947 /**
948  * proc_dou8vec_minmax - read a vector of unsigned chars with min/max values
949  * @table: the sysctl table
950  * @write: %TRUE if this is a write to the sysctl file
951  * @buffer: the user buffer
952  * @lenp: the size of the user buffer
953  * @ppos: file position
954  *
955  * Reads/writes up to table->maxlen/sizeof(u8) unsigned chars
956  * values from/to the user buffer, treated as an ASCII string. Negative
957  * strings are not allowed.
958  *
959  * This routine will ensure the values are within the range specified by
960  * table->extra1 (min) and table->extra2 (max).
961  *
962  * Returns 0 on success or an error on write when the range check fails.
963  */
964 int proc_dou8vec_minmax(struct ctl_table *table, int write,
965 			void *buffer, size_t *lenp, loff_t *ppos)
966 {
967 	struct ctl_table tmp;
968 	unsigned int min = 0, max = 255U, val;
969 	u8 *data = table->data;
970 	struct do_proc_douintvec_minmax_conv_param param = {
971 		.min = &min,
972 		.max = &max,
973 	};
974 	int res;
975 
976 	/* Do not support arrays yet. */
977 	if (table->maxlen != sizeof(u8))
978 		return -EINVAL;
979 
980 	if (table->extra1) {
981 		min = *(unsigned int *) table->extra1;
982 		if (min > 255U)
983 			return -EINVAL;
984 	}
985 	if (table->extra2) {
986 		max = *(unsigned int *) table->extra2;
987 		if (max > 255U)
988 			return -EINVAL;
989 	}
990 
991 	tmp = *table;
992 
993 	tmp.maxlen = sizeof(val);
994 	tmp.data = &val;
995 	val = READ_ONCE(*data);
996 	res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
997 				do_proc_douintvec_minmax_conv, &param);
998 	if (res)
999 		return res;
1000 	if (write)
1001 		WRITE_ONCE(*data, val);
1002 	return 0;
1003 }
1004 EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
1005 
1006 #ifdef CONFIG_MAGIC_SYSRQ
1007 static int sysrq_sysctl_handler(struct ctl_table *table, int write,
1008 				void *buffer, size_t *lenp, loff_t *ppos)
1009 {
1010 	int tmp, ret;
1011 
1012 	tmp = sysrq_mask();
1013 
1014 	ret = __do_proc_dointvec(&tmp, table, write, buffer,
1015 			       lenp, ppos, NULL, NULL);
1016 	if (ret || !write)
1017 		return ret;
1018 
1019 	if (write)
1020 		sysrq_toggle_support(tmp);
1021 
1022 	return 0;
1023 }
1024 #endif
1025 
1026 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table,
1027 		int write, void *buffer, size_t *lenp, loff_t *ppos,
1028 		unsigned long convmul, unsigned long convdiv)
1029 {
1030 	unsigned long *i, *min, *max;
1031 	int vleft, first = 1, err = 0;
1032 	size_t left;
1033 	char *p;
1034 
1035 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
1036 		*lenp = 0;
1037 		return 0;
1038 	}
1039 
1040 	i = data;
1041 	min = table->extra1;
1042 	max = table->extra2;
1043 	vleft = table->maxlen / sizeof(unsigned long);
1044 	left = *lenp;
1045 
1046 	if (write) {
1047 		if (proc_first_pos_non_zero_ignore(ppos, table))
1048 			goto out;
1049 
1050 		if (left > PAGE_SIZE - 1)
1051 			left = PAGE_SIZE - 1;
1052 		p = buffer;
1053 	}
1054 
1055 	for (; left && vleft--; i++, first = 0) {
1056 		unsigned long val;
1057 
1058 		if (write) {
1059 			bool neg;
1060 
1061 			proc_skip_spaces(&p, &left);
1062 			if (!left)
1063 				break;
1064 
1065 			err = proc_get_long(&p, &left, &val, &neg,
1066 					     proc_wspace_sep,
1067 					     sizeof(proc_wspace_sep), NULL);
1068 			if (err || neg) {
1069 				err = -EINVAL;
1070 				break;
1071 			}
1072 
1073 			val = convmul * val / convdiv;
1074 			if ((min && val < *min) || (max && val > *max)) {
1075 				err = -EINVAL;
1076 				break;
1077 			}
1078 			WRITE_ONCE(*i, val);
1079 		} else {
1080 			val = convdiv * READ_ONCE(*i) / convmul;
1081 			if (!first)
1082 				proc_put_char(&buffer, &left, '\t');
1083 			proc_put_long(&buffer, &left, val, false);
1084 		}
1085 	}
1086 
1087 	if (!write && !first && left && !err)
1088 		proc_put_char(&buffer, &left, '\n');
1089 	if (write && !err)
1090 		proc_skip_spaces(&p, &left);
1091 	if (write && first)
1092 		return err ? : -EINVAL;
1093 	*lenp -= left;
1094 out:
1095 	*ppos += *lenp;
1096 	return err;
1097 }
1098 
1099 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
1100 		void *buffer, size_t *lenp, loff_t *ppos, unsigned long convmul,
1101 		unsigned long convdiv)
1102 {
1103 	return __do_proc_doulongvec_minmax(table->data, table, write,
1104 			buffer, lenp, ppos, convmul, convdiv);
1105 }
1106 
1107 /**
1108  * proc_doulongvec_minmax - read a vector of long integers with min/max values
1109  * @table: the sysctl table
1110  * @write: %TRUE if this is a write to the sysctl file
1111  * @buffer: the user buffer
1112  * @lenp: the size of the user buffer
1113  * @ppos: file position
1114  *
1115  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
1116  * values from/to the user buffer, treated as an ASCII string.
1117  *
1118  * This routine will ensure the values are within the range specified by
1119  * table->extra1 (min) and table->extra2 (max).
1120  *
1121  * Returns 0 on success.
1122  */
1123 int proc_doulongvec_minmax(struct ctl_table *table, int write,
1124 			   void *buffer, size_t *lenp, loff_t *ppos)
1125 {
1126     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
1127 }
1128 
1129 /**
1130  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
1131  * @table: the sysctl table
1132  * @write: %TRUE if this is a write to the sysctl file
1133  * @buffer: the user buffer
1134  * @lenp: the size of the user buffer
1135  * @ppos: file position
1136  *
1137  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
1138  * values from/to the user buffer, treated as an ASCII string. The values
1139  * are treated as milliseconds, and converted to jiffies when they are stored.
1140  *
1141  * This routine will ensure the values are within the range specified by
1142  * table->extra1 (min) and table->extra2 (max).
1143  *
1144  * Returns 0 on success.
1145  */
1146 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1147 				      void *buffer, size_t *lenp, loff_t *ppos)
1148 {
1149     return do_proc_doulongvec_minmax(table, write, buffer,
1150 				     lenp, ppos, HZ, 1000l);
1151 }
1152 
1153 
1154 static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
1155 					 int *valp,
1156 					 int write, void *data)
1157 {
1158 	if (write) {
1159 		if (*lvalp > INT_MAX / HZ)
1160 			return 1;
1161 		if (*negp)
1162 			WRITE_ONCE(*valp, -*lvalp * HZ);
1163 		else
1164 			WRITE_ONCE(*valp, *lvalp * HZ);
1165 	} else {
1166 		int val = READ_ONCE(*valp);
1167 		unsigned long lval;
1168 		if (val < 0) {
1169 			*negp = true;
1170 			lval = -(unsigned long)val;
1171 		} else {
1172 			*negp = false;
1173 			lval = (unsigned long)val;
1174 		}
1175 		*lvalp = lval / HZ;
1176 	}
1177 	return 0;
1178 }
1179 
1180 static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
1181 						int *valp,
1182 						int write, void *data)
1183 {
1184 	if (write) {
1185 		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
1186 			return 1;
1187 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
1188 	} else {
1189 		int val = *valp;
1190 		unsigned long lval;
1191 		if (val < 0) {
1192 			*negp = true;
1193 			lval = -(unsigned long)val;
1194 		} else {
1195 			*negp = false;
1196 			lval = (unsigned long)val;
1197 		}
1198 		*lvalp = jiffies_to_clock_t(lval);
1199 	}
1200 	return 0;
1201 }
1202 
1203 static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
1204 					    int *valp,
1205 					    int write, void *data)
1206 {
1207 	if (write) {
1208 		unsigned long jif = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
1209 
1210 		if (jif > INT_MAX)
1211 			return 1;
1212 		WRITE_ONCE(*valp, (int)jif);
1213 	} else {
1214 		int val = READ_ONCE(*valp);
1215 		unsigned long lval;
1216 		if (val < 0) {
1217 			*negp = true;
1218 			lval = -(unsigned long)val;
1219 		} else {
1220 			*negp = false;
1221 			lval = (unsigned long)val;
1222 		}
1223 		*lvalp = jiffies_to_msecs(lval);
1224 	}
1225 	return 0;
1226 }
1227 
1228 static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lvalp,
1229 						int *valp, int write, void *data)
1230 {
1231 	int tmp, ret;
1232 	struct do_proc_dointvec_minmax_conv_param *param = data;
1233 	/*
1234 	 * If writing, first do so via a temporary local int so we can
1235 	 * bounds-check it before touching *valp.
1236 	 */
1237 	int *ip = write ? &tmp : valp;
1238 
1239 	ret = do_proc_dointvec_ms_jiffies_conv(negp, lvalp, ip, write, data);
1240 	if (ret)
1241 		return ret;
1242 
1243 	if (write) {
1244 		if ((param->min && *param->min > tmp) ||
1245 				(param->max && *param->max < tmp))
1246 			return -EINVAL;
1247 		*valp = tmp;
1248 	}
1249 	return 0;
1250 }
1251 
1252 /**
1253  * proc_dointvec_jiffies - read a vector of integers as seconds
1254  * @table: the sysctl table
1255  * @write: %TRUE if this is a write to the sysctl file
1256  * @buffer: the user buffer
1257  * @lenp: the size of the user buffer
1258  * @ppos: file position
1259  *
1260  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1261  * values from/to the user buffer, treated as an ASCII string.
1262  * The values read are assumed to be in seconds, and are converted into
1263  * jiffies.
1264  *
1265  * Returns 0 on success.
1266  */
1267 int proc_dointvec_jiffies(struct ctl_table *table, int write,
1268 			  void *buffer, size_t *lenp, loff_t *ppos)
1269 {
1270     return do_proc_dointvec(table,write,buffer,lenp,ppos,
1271 		    	    do_proc_dointvec_jiffies_conv,NULL);
1272 }
1273 
1274 int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1275 			  void *buffer, size_t *lenp, loff_t *ppos)
1276 {
1277 	struct do_proc_dointvec_minmax_conv_param param = {
1278 		.min = (int *) table->extra1,
1279 		.max = (int *) table->extra2,
1280 	};
1281 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
1282 			do_proc_dointvec_ms_jiffies_minmax_conv, &param);
1283 }
1284 
1285 /**
1286  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
1287  * @table: the sysctl table
1288  * @write: %TRUE if this is a write to the sysctl file
1289  * @buffer: the user buffer
1290  * @lenp: the size of the user buffer
1291  * @ppos: pointer to the file position
1292  *
1293  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1294  * values from/to the user buffer, treated as an ASCII string.
1295  * The values read are assumed to be in 1/USER_HZ seconds, and
1296  * are converted into jiffies.
1297  *
1298  * Returns 0 on success.
1299  */
1300 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
1301 				 void *buffer, size_t *lenp, loff_t *ppos)
1302 {
1303 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
1304 				do_proc_dointvec_userhz_jiffies_conv, NULL);
1305 }
1306 
1307 /**
1308  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
1309  * @table: the sysctl table
1310  * @write: %TRUE if this is a write to the sysctl file
1311  * @buffer: the user buffer
1312  * @lenp: the size of the user buffer
1313  * @ppos: file position
1314  * @ppos: the current position in the file
1315  *
1316  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1317  * values from/to the user buffer, treated as an ASCII string.
1318  * The values read are assumed to be in 1/1000 seconds, and
1319  * are converted into jiffies.
1320  *
1321  * Returns 0 on success.
1322  */
1323 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, void *buffer,
1324 		size_t *lenp, loff_t *ppos)
1325 {
1326 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
1327 				do_proc_dointvec_ms_jiffies_conv, NULL);
1328 }
1329 
1330 static int proc_do_cad_pid(struct ctl_table *table, int write, void *buffer,
1331 		size_t *lenp, loff_t *ppos)
1332 {
1333 	struct pid *new_pid;
1334 	pid_t tmp;
1335 	int r;
1336 
1337 	tmp = pid_vnr(cad_pid);
1338 
1339 	r = __do_proc_dointvec(&tmp, table, write, buffer,
1340 			       lenp, ppos, NULL, NULL);
1341 	if (r || !write)
1342 		return r;
1343 
1344 	new_pid = find_get_pid(tmp);
1345 	if (!new_pid)
1346 		return -ESRCH;
1347 
1348 	put_pid(xchg(&cad_pid, new_pid));
1349 	return 0;
1350 }
1351 
1352 /**
1353  * proc_do_large_bitmap - read/write from/to a large bitmap
1354  * @table: the sysctl table
1355  * @write: %TRUE if this is a write to the sysctl file
1356  * @buffer: the user buffer
1357  * @lenp: the size of the user buffer
1358  * @ppos: file position
1359  *
1360  * The bitmap is stored at table->data and the bitmap length (in bits)
1361  * in table->maxlen.
1362  *
1363  * We use a range comma separated format (e.g. 1,3-4,10-10) so that
1364  * large bitmaps may be represented in a compact manner. Writing into
1365  * the file will clear the bitmap then update it with the given input.
1366  *
1367  * Returns 0 on success.
1368  */
1369 int proc_do_large_bitmap(struct ctl_table *table, int write,
1370 			 void *buffer, size_t *lenp, loff_t *ppos)
1371 {
1372 	int err = 0;
1373 	size_t left = *lenp;
1374 	unsigned long bitmap_len = table->maxlen;
1375 	unsigned long *bitmap = *(unsigned long **) table->data;
1376 	unsigned long *tmp_bitmap = NULL;
1377 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
1378 
1379 	if (!bitmap || !bitmap_len || !left || (*ppos && !write)) {
1380 		*lenp = 0;
1381 		return 0;
1382 	}
1383 
1384 	if (write) {
1385 		char *p = buffer;
1386 		size_t skipped = 0;
1387 
1388 		if (left > PAGE_SIZE - 1) {
1389 			left = PAGE_SIZE - 1;
1390 			/* How much of the buffer we'll skip this pass */
1391 			skipped = *lenp - left;
1392 		}
1393 
1394 		tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL);
1395 		if (!tmp_bitmap)
1396 			return -ENOMEM;
1397 		proc_skip_char(&p, &left, '\n');
1398 		while (!err && left) {
1399 			unsigned long val_a, val_b;
1400 			bool neg;
1401 			size_t saved_left;
1402 
1403 			/* In case we stop parsing mid-number, we can reset */
1404 			saved_left = left;
1405 			err = proc_get_long(&p, &left, &val_a, &neg, tr_a,
1406 					     sizeof(tr_a), &c);
1407 			/*
1408 			 * If we consumed the entirety of a truncated buffer or
1409 			 * only one char is left (may be a "-"), then stop here,
1410 			 * reset, & come back for more.
1411 			 */
1412 			if ((left <= 1) && skipped) {
1413 				left = saved_left;
1414 				break;
1415 			}
1416 
1417 			if (err)
1418 				break;
1419 			if (val_a >= bitmap_len || neg) {
1420 				err = -EINVAL;
1421 				break;
1422 			}
1423 
1424 			val_b = val_a;
1425 			if (left) {
1426 				p++;
1427 				left--;
1428 			}
1429 
1430 			if (c == '-') {
1431 				err = proc_get_long(&p, &left, &val_b,
1432 						     &neg, tr_b, sizeof(tr_b),
1433 						     &c);
1434 				/*
1435 				 * If we consumed all of a truncated buffer or
1436 				 * then stop here, reset, & come back for more.
1437 				 */
1438 				if (!left && skipped) {
1439 					left = saved_left;
1440 					break;
1441 				}
1442 
1443 				if (err)
1444 					break;
1445 				if (val_b >= bitmap_len || neg ||
1446 				    val_a > val_b) {
1447 					err = -EINVAL;
1448 					break;
1449 				}
1450 				if (left) {
1451 					p++;
1452 					left--;
1453 				}
1454 			}
1455 
1456 			bitmap_set(tmp_bitmap, val_a, val_b - val_a + 1);
1457 			proc_skip_char(&p, &left, '\n');
1458 		}
1459 		left += skipped;
1460 	} else {
1461 		unsigned long bit_a, bit_b = 0;
1462 		bool first = 1;
1463 
1464 		while (left) {
1465 			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
1466 			if (bit_a >= bitmap_len)
1467 				break;
1468 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
1469 						   bit_a + 1) - 1;
1470 
1471 			if (!first)
1472 				proc_put_char(&buffer, &left, ',');
1473 			proc_put_long(&buffer, &left, bit_a, false);
1474 			if (bit_a != bit_b) {
1475 				proc_put_char(&buffer, &left, '-');
1476 				proc_put_long(&buffer, &left, bit_b, false);
1477 			}
1478 
1479 			first = 0; bit_b++;
1480 		}
1481 		proc_put_char(&buffer, &left, '\n');
1482 	}
1483 
1484 	if (!err) {
1485 		if (write) {
1486 			if (*ppos)
1487 				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
1488 			else
1489 				bitmap_copy(bitmap, tmp_bitmap, bitmap_len);
1490 		}
1491 		*lenp -= left;
1492 		*ppos += *lenp;
1493 	}
1494 
1495 	bitmap_free(tmp_bitmap);
1496 	return err;
1497 }
1498 
1499 #else /* CONFIG_PROC_SYSCTL */
1500 
1501 int proc_dostring(struct ctl_table *table, int write,
1502 		  void *buffer, size_t *lenp, loff_t *ppos)
1503 {
1504 	return -ENOSYS;
1505 }
1506 
1507 int proc_dobool(struct ctl_table *table, int write,
1508 		void *buffer, size_t *lenp, loff_t *ppos)
1509 {
1510 	return -ENOSYS;
1511 }
1512 
1513 int proc_dointvec(struct ctl_table *table, int write,
1514 		  void *buffer, size_t *lenp, loff_t *ppos)
1515 {
1516 	return -ENOSYS;
1517 }
1518 
1519 int proc_douintvec(struct ctl_table *table, int write,
1520 		  void *buffer, size_t *lenp, loff_t *ppos)
1521 {
1522 	return -ENOSYS;
1523 }
1524 
1525 int proc_dointvec_minmax(struct ctl_table *table, int write,
1526 		    void *buffer, size_t *lenp, loff_t *ppos)
1527 {
1528 	return -ENOSYS;
1529 }
1530 
1531 int proc_douintvec_minmax(struct ctl_table *table, int write,
1532 			  void *buffer, size_t *lenp, loff_t *ppos)
1533 {
1534 	return -ENOSYS;
1535 }
1536 
1537 int proc_dou8vec_minmax(struct ctl_table *table, int write,
1538 			void *buffer, size_t *lenp, loff_t *ppos)
1539 {
1540 	return -ENOSYS;
1541 }
1542 
1543 int proc_dointvec_jiffies(struct ctl_table *table, int write,
1544 		    void *buffer, size_t *lenp, loff_t *ppos)
1545 {
1546 	return -ENOSYS;
1547 }
1548 
1549 int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1550 				    void *buffer, size_t *lenp, loff_t *ppos)
1551 {
1552 	return -ENOSYS;
1553 }
1554 
1555 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
1556 		    void *buffer, size_t *lenp, loff_t *ppos)
1557 {
1558 	return -ENOSYS;
1559 }
1560 
1561 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
1562 			     void *buffer, size_t *lenp, loff_t *ppos)
1563 {
1564 	return -ENOSYS;
1565 }
1566 
1567 int proc_doulongvec_minmax(struct ctl_table *table, int write,
1568 		    void *buffer, size_t *lenp, loff_t *ppos)
1569 {
1570 	return -ENOSYS;
1571 }
1572 
1573 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1574 				      void *buffer, size_t *lenp, loff_t *ppos)
1575 {
1576 	return -ENOSYS;
1577 }
1578 
1579 int proc_do_large_bitmap(struct ctl_table *table, int write,
1580 			 void *buffer, size_t *lenp, loff_t *ppos)
1581 {
1582 	return -ENOSYS;
1583 }
1584 
1585 #endif /* CONFIG_PROC_SYSCTL */
1586 
1587 #if defined(CONFIG_SYSCTL)
1588 int proc_do_static_key(struct ctl_table *table, int write,
1589 		       void *buffer, size_t *lenp, loff_t *ppos)
1590 {
1591 	struct static_key *key = (struct static_key *)table->data;
1592 	static DEFINE_MUTEX(static_key_mutex);
1593 	int val, ret;
1594 	struct ctl_table tmp = {
1595 		.data   = &val,
1596 		.maxlen = sizeof(val),
1597 		.mode   = table->mode,
1598 		.extra1 = SYSCTL_ZERO,
1599 		.extra2 = SYSCTL_ONE,
1600 	};
1601 
1602 	if (write && !capable(CAP_SYS_ADMIN))
1603 		return -EPERM;
1604 
1605 	mutex_lock(&static_key_mutex);
1606 	val = static_key_enabled(key);
1607 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
1608 	if (write && !ret) {
1609 		if (val)
1610 			static_key_enable(key);
1611 		else
1612 			static_key_disable(key);
1613 	}
1614 	mutex_unlock(&static_key_mutex);
1615 	return ret;
1616 }
1617 
1618 static struct ctl_table kern_table[] = {
1619 	{
1620 		.procname	= "panic",
1621 		.data		= &panic_timeout,
1622 		.maxlen		= sizeof(int),
1623 		.mode		= 0644,
1624 		.proc_handler	= proc_dointvec,
1625 	},
1626 #ifdef CONFIG_PROC_SYSCTL
1627 	{
1628 		.procname	= "tainted",
1629 		.maxlen 	= sizeof(long),
1630 		.mode		= 0644,
1631 		.proc_handler	= proc_taint,
1632 	},
1633 	{
1634 		.procname	= "sysctl_writes_strict",
1635 		.data		= &sysctl_writes_strict,
1636 		.maxlen		= sizeof(int),
1637 		.mode		= 0644,
1638 		.proc_handler	= proc_dointvec_minmax,
1639 		.extra1		= SYSCTL_NEG_ONE,
1640 		.extra2		= SYSCTL_ONE,
1641 	},
1642 #endif
1643 	{
1644 		.procname	= "print-fatal-signals",
1645 		.data		= &print_fatal_signals,
1646 		.maxlen		= sizeof(int),
1647 		.mode		= 0644,
1648 		.proc_handler	= proc_dointvec,
1649 	},
1650 #ifdef CONFIG_SPARC
1651 	{
1652 		.procname	= "reboot-cmd",
1653 		.data		= reboot_command,
1654 		.maxlen		= 256,
1655 		.mode		= 0644,
1656 		.proc_handler	= proc_dostring,
1657 	},
1658 	{
1659 		.procname	= "stop-a",
1660 		.data		= &stop_a_enabled,
1661 		.maxlen		= sizeof (int),
1662 		.mode		= 0644,
1663 		.proc_handler	= proc_dointvec,
1664 	},
1665 	{
1666 		.procname	= "scons-poweroff",
1667 		.data		= &scons_pwroff,
1668 		.maxlen		= sizeof (int),
1669 		.mode		= 0644,
1670 		.proc_handler	= proc_dointvec,
1671 	},
1672 #endif
1673 #ifdef CONFIG_SPARC64
1674 	{
1675 		.procname	= "tsb-ratio",
1676 		.data		= &sysctl_tsb_ratio,
1677 		.maxlen		= sizeof (int),
1678 		.mode		= 0644,
1679 		.proc_handler	= proc_dointvec,
1680 	},
1681 #endif
1682 #ifdef CONFIG_PARISC
1683 	{
1684 		.procname	= "soft-power",
1685 		.data		= &pwrsw_enabled,
1686 		.maxlen		= sizeof (int),
1687 		.mode		= 0644,
1688 		.proc_handler	= proc_dointvec,
1689 	},
1690 #endif
1691 #ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
1692 	{
1693 		.procname	= "unaligned-trap",
1694 		.data		= &unaligned_enabled,
1695 		.maxlen		= sizeof (int),
1696 		.mode		= 0644,
1697 		.proc_handler	= proc_dointvec,
1698 	},
1699 #endif
1700 #ifdef CONFIG_STACK_TRACER
1701 	{
1702 		.procname	= "stack_tracer_enabled",
1703 		.data		= &stack_tracer_enabled,
1704 		.maxlen		= sizeof(int),
1705 		.mode		= 0644,
1706 		.proc_handler	= stack_trace_sysctl,
1707 	},
1708 #endif
1709 #ifdef CONFIG_TRACING
1710 	{
1711 		.procname	= "ftrace_dump_on_oops",
1712 		.data		= &ftrace_dump_on_oops,
1713 		.maxlen		= MAX_TRACER_SIZE,
1714 		.mode		= 0644,
1715 		.proc_handler	= proc_dostring,
1716 	},
1717 	{
1718 		.procname	= "traceoff_on_warning",
1719 		.data		= &__disable_trace_on_warning,
1720 		.maxlen		= sizeof(__disable_trace_on_warning),
1721 		.mode		= 0644,
1722 		.proc_handler	= proc_dointvec,
1723 	},
1724 	{
1725 		.procname	= "tracepoint_printk",
1726 		.data		= &tracepoint_printk,
1727 		.maxlen		= sizeof(tracepoint_printk),
1728 		.mode		= 0644,
1729 		.proc_handler	= tracepoint_printk_sysctl,
1730 	},
1731 #endif
1732 #ifdef CONFIG_MODULES
1733 	{
1734 		.procname	= "modprobe",
1735 		.data		= &modprobe_path,
1736 		.maxlen		= KMOD_PATH_LEN,
1737 		.mode		= 0644,
1738 		.proc_handler	= proc_dostring,
1739 	},
1740 	{
1741 		.procname	= "modules_disabled",
1742 		.data		= &modules_disabled,
1743 		.maxlen		= sizeof(int),
1744 		.mode		= 0644,
1745 		/* only handle a transition from default "0" to "1" */
1746 		.proc_handler	= proc_dointvec_minmax,
1747 		.extra1		= SYSCTL_ONE,
1748 		.extra2		= SYSCTL_ONE,
1749 	},
1750 #endif
1751 #ifdef CONFIG_UEVENT_HELPER
1752 	{
1753 		.procname	= "hotplug",
1754 		.data		= &uevent_helper,
1755 		.maxlen		= UEVENT_HELPER_PATH_LEN,
1756 		.mode		= 0644,
1757 		.proc_handler	= proc_dostring,
1758 	},
1759 #endif
1760 #ifdef CONFIG_MAGIC_SYSRQ
1761 	{
1762 		.procname	= "sysrq",
1763 		.data		= NULL,
1764 		.maxlen		= sizeof (int),
1765 		.mode		= 0644,
1766 		.proc_handler	= sysrq_sysctl_handler,
1767 	},
1768 #endif
1769 #ifdef CONFIG_PROC_SYSCTL
1770 	{
1771 		.procname	= "cad_pid",
1772 		.data		= NULL,
1773 		.maxlen		= sizeof (int),
1774 		.mode		= 0600,
1775 		.proc_handler	= proc_do_cad_pid,
1776 	},
1777 #endif
1778 	{
1779 		.procname	= "threads-max",
1780 		.data		= NULL,
1781 		.maxlen		= sizeof(int),
1782 		.mode		= 0644,
1783 		.proc_handler	= sysctl_max_threads,
1784 	},
1785 	{
1786 		.procname	= "overflowuid",
1787 		.data		= &overflowuid,
1788 		.maxlen		= sizeof(int),
1789 		.mode		= 0644,
1790 		.proc_handler	= proc_dointvec_minmax,
1791 		.extra1		= SYSCTL_ZERO,
1792 		.extra2		= SYSCTL_MAXOLDUID,
1793 	},
1794 	{
1795 		.procname	= "overflowgid",
1796 		.data		= &overflowgid,
1797 		.maxlen		= sizeof(int),
1798 		.mode		= 0644,
1799 		.proc_handler	= proc_dointvec_minmax,
1800 		.extra1		= SYSCTL_ZERO,
1801 		.extra2		= SYSCTL_MAXOLDUID,
1802 	},
1803 #ifdef CONFIG_S390
1804 	{
1805 		.procname	= "userprocess_debug",
1806 		.data		= &show_unhandled_signals,
1807 		.maxlen		= sizeof(int),
1808 		.mode		= 0644,
1809 		.proc_handler	= proc_dointvec,
1810 	},
1811 #endif
1812 	{
1813 		.procname	= "pid_max",
1814 		.data		= &pid_max,
1815 		.maxlen		= sizeof (int),
1816 		.mode		= 0644,
1817 		.proc_handler	= proc_dointvec_minmax,
1818 		.extra1		= &pid_max_min,
1819 		.extra2		= &pid_max_max,
1820 	},
1821 	{
1822 		.procname	= "panic_on_oops",
1823 		.data		= &panic_on_oops,
1824 		.maxlen		= sizeof(int),
1825 		.mode		= 0644,
1826 		.proc_handler	= proc_dointvec,
1827 	},
1828 	{
1829 		.procname	= "panic_print",
1830 		.data		= &panic_print,
1831 		.maxlen		= sizeof(unsigned long),
1832 		.mode		= 0644,
1833 		.proc_handler	= proc_doulongvec_minmax,
1834 	},
1835 	{
1836 		.procname	= "ngroups_max",
1837 		.data		= (void *)&ngroups_max,
1838 		.maxlen		= sizeof (int),
1839 		.mode		= 0444,
1840 		.proc_handler	= proc_dointvec,
1841 	},
1842 	{
1843 		.procname	= "cap_last_cap",
1844 		.data		= (void *)&cap_last_cap,
1845 		.maxlen		= sizeof(int),
1846 		.mode		= 0444,
1847 		.proc_handler	= proc_dointvec,
1848 	},
1849 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
1850 	{
1851 		.procname       = "unknown_nmi_panic",
1852 		.data           = &unknown_nmi_panic,
1853 		.maxlen         = sizeof (int),
1854 		.mode           = 0644,
1855 		.proc_handler   = proc_dointvec,
1856 	},
1857 #endif
1858 
1859 #if (defined(CONFIG_X86_32) || defined(CONFIG_PARISC)) && \
1860 	defined(CONFIG_DEBUG_STACKOVERFLOW)
1861 	{
1862 		.procname	= "panic_on_stackoverflow",
1863 		.data		= &sysctl_panic_on_stackoverflow,
1864 		.maxlen		= sizeof(int),
1865 		.mode		= 0644,
1866 		.proc_handler	= proc_dointvec,
1867 	},
1868 #endif
1869 #if defined(CONFIG_X86)
1870 	{
1871 		.procname	= "panic_on_unrecovered_nmi",
1872 		.data		= &panic_on_unrecovered_nmi,
1873 		.maxlen		= sizeof(int),
1874 		.mode		= 0644,
1875 		.proc_handler	= proc_dointvec,
1876 	},
1877 	{
1878 		.procname	= "panic_on_io_nmi",
1879 		.data		= &panic_on_io_nmi,
1880 		.maxlen		= sizeof(int),
1881 		.mode		= 0644,
1882 		.proc_handler	= proc_dointvec,
1883 	},
1884 	{
1885 		.procname	= "bootloader_type",
1886 		.data		= &bootloader_type,
1887 		.maxlen		= sizeof (int),
1888 		.mode		= 0444,
1889 		.proc_handler	= proc_dointvec,
1890 	},
1891 	{
1892 		.procname	= "bootloader_version",
1893 		.data		= &bootloader_version,
1894 		.maxlen		= sizeof (int),
1895 		.mode		= 0444,
1896 		.proc_handler	= proc_dointvec,
1897 	},
1898 	{
1899 		.procname	= "io_delay_type",
1900 		.data		= &io_delay_type,
1901 		.maxlen		= sizeof(int),
1902 		.mode		= 0644,
1903 		.proc_handler	= proc_dointvec,
1904 	},
1905 #endif
1906 #if defined(CONFIG_MMU)
1907 	{
1908 		.procname	= "randomize_va_space",
1909 		.data		= &randomize_va_space,
1910 		.maxlen		= sizeof(int),
1911 		.mode		= 0644,
1912 		.proc_handler	= proc_dointvec,
1913 	},
1914 #endif
1915 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
1916 	{
1917 		.procname	= "spin_retry",
1918 		.data		= &spin_retry,
1919 		.maxlen		= sizeof (int),
1920 		.mode		= 0644,
1921 		.proc_handler	= proc_dointvec,
1922 	},
1923 #endif
1924 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
1925 	{
1926 		.procname	= "acpi_video_flags",
1927 		.data		= &acpi_realmode_flags,
1928 		.maxlen		= sizeof (unsigned long),
1929 		.mode		= 0644,
1930 		.proc_handler	= proc_doulongvec_minmax,
1931 	},
1932 #endif
1933 #ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
1934 	{
1935 		.procname	= "ignore-unaligned-usertrap",
1936 		.data		= &no_unaligned_warning,
1937 		.maxlen		= sizeof (int),
1938 		.mode		= 0644,
1939 		.proc_handler	= proc_dointvec,
1940 	},
1941 #endif
1942 #ifdef CONFIG_RT_MUTEXES
1943 	{
1944 		.procname	= "max_lock_depth",
1945 		.data		= &max_lock_depth,
1946 		.maxlen		= sizeof(int),
1947 		.mode		= 0644,
1948 		.proc_handler	= proc_dointvec,
1949 	},
1950 #endif
1951 #ifdef CONFIG_PERF_EVENTS
1952 	/*
1953 	 * User-space scripts rely on the existence of this file
1954 	 * as a feature check for perf_events being enabled.
1955 	 *
1956 	 * So it's an ABI, do not remove!
1957 	 */
1958 	{
1959 		.procname	= "perf_event_paranoid",
1960 		.data		= &sysctl_perf_event_paranoid,
1961 		.maxlen		= sizeof(sysctl_perf_event_paranoid),
1962 		.mode		= 0644,
1963 		.proc_handler	= proc_dointvec,
1964 	},
1965 	{
1966 		.procname	= "perf_event_mlock_kb",
1967 		.data		= &sysctl_perf_event_mlock,
1968 		.maxlen		= sizeof(sysctl_perf_event_mlock),
1969 		.mode		= 0644,
1970 		.proc_handler	= proc_dointvec,
1971 	},
1972 	{
1973 		.procname	= "perf_event_max_sample_rate",
1974 		.data		= &sysctl_perf_event_sample_rate,
1975 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
1976 		.mode		= 0644,
1977 		.proc_handler	= perf_event_max_sample_rate_handler,
1978 		.extra1		= SYSCTL_ONE,
1979 	},
1980 	{
1981 		.procname	= "perf_cpu_time_max_percent",
1982 		.data		= &sysctl_perf_cpu_time_max_percent,
1983 		.maxlen		= sizeof(sysctl_perf_cpu_time_max_percent),
1984 		.mode		= 0644,
1985 		.proc_handler	= perf_cpu_time_max_percent_handler,
1986 		.extra1		= SYSCTL_ZERO,
1987 		.extra2		= SYSCTL_ONE_HUNDRED,
1988 	},
1989 	{
1990 		.procname	= "perf_event_max_stack",
1991 		.data		= &sysctl_perf_event_max_stack,
1992 		.maxlen		= sizeof(sysctl_perf_event_max_stack),
1993 		.mode		= 0644,
1994 		.proc_handler	= perf_event_max_stack_handler,
1995 		.extra1		= SYSCTL_ZERO,
1996 		.extra2		= (void *)&six_hundred_forty_kb,
1997 	},
1998 	{
1999 		.procname	= "perf_event_max_contexts_per_stack",
2000 		.data		= &sysctl_perf_event_max_contexts_per_stack,
2001 		.maxlen		= sizeof(sysctl_perf_event_max_contexts_per_stack),
2002 		.mode		= 0644,
2003 		.proc_handler	= perf_event_max_stack_handler,
2004 		.extra1		= SYSCTL_ZERO,
2005 		.extra2		= SYSCTL_ONE_THOUSAND,
2006 	},
2007 #endif
2008 	{
2009 		.procname	= "panic_on_warn",
2010 		.data		= &panic_on_warn,
2011 		.maxlen		= sizeof(int),
2012 		.mode		= 0644,
2013 		.proc_handler	= proc_dointvec_minmax,
2014 		.extra1		= SYSCTL_ZERO,
2015 		.extra2		= SYSCTL_ONE,
2016 	},
2017 #ifdef CONFIG_TREE_RCU
2018 	{
2019 		.procname	= "panic_on_rcu_stall",
2020 		.data		= &sysctl_panic_on_rcu_stall,
2021 		.maxlen		= sizeof(sysctl_panic_on_rcu_stall),
2022 		.mode		= 0644,
2023 		.proc_handler	= proc_dointvec_minmax,
2024 		.extra1		= SYSCTL_ZERO,
2025 		.extra2		= SYSCTL_ONE,
2026 	},
2027 	{
2028 		.procname	= "max_rcu_stall_to_panic",
2029 		.data		= &sysctl_max_rcu_stall_to_panic,
2030 		.maxlen		= sizeof(sysctl_max_rcu_stall_to_panic),
2031 		.mode		= 0644,
2032 		.proc_handler	= proc_dointvec_minmax,
2033 		.extra1		= SYSCTL_ONE,
2034 		.extra2		= SYSCTL_INT_MAX,
2035 	},
2036 #endif
2037 	{ }
2038 };
2039 
2040 static struct ctl_table vm_table[] = {
2041 	{
2042 		.procname	= "overcommit_memory",
2043 		.data		= &sysctl_overcommit_memory,
2044 		.maxlen		= sizeof(sysctl_overcommit_memory),
2045 		.mode		= 0644,
2046 		.proc_handler	= overcommit_policy_handler,
2047 		.extra1		= SYSCTL_ZERO,
2048 		.extra2		= SYSCTL_TWO,
2049 	},
2050 	{
2051 		.procname	= "overcommit_ratio",
2052 		.data		= &sysctl_overcommit_ratio,
2053 		.maxlen		= sizeof(sysctl_overcommit_ratio),
2054 		.mode		= 0644,
2055 		.proc_handler	= overcommit_ratio_handler,
2056 	},
2057 	{
2058 		.procname	= "overcommit_kbytes",
2059 		.data		= &sysctl_overcommit_kbytes,
2060 		.maxlen		= sizeof(sysctl_overcommit_kbytes),
2061 		.mode		= 0644,
2062 		.proc_handler	= overcommit_kbytes_handler,
2063 	},
2064 	{
2065 		.procname	= "page-cluster",
2066 		.data		= &page_cluster,
2067 		.maxlen		= sizeof(int),
2068 		.mode		= 0644,
2069 		.proc_handler	= proc_dointvec_minmax,
2070 		.extra1		= SYSCTL_ZERO,
2071 		.extra2		= (void *)&page_cluster_max,
2072 	},
2073 	{
2074 		.procname	= "dirtytime_expire_seconds",
2075 		.data		= &dirtytime_expire_interval,
2076 		.maxlen		= sizeof(dirtytime_expire_interval),
2077 		.mode		= 0644,
2078 		.proc_handler	= dirtytime_interval_handler,
2079 		.extra1		= SYSCTL_ZERO,
2080 	},
2081 	{
2082 		.procname	= "swappiness",
2083 		.data		= &vm_swappiness,
2084 		.maxlen		= sizeof(vm_swappiness),
2085 		.mode		= 0644,
2086 		.proc_handler	= proc_dointvec_minmax,
2087 		.extra1		= SYSCTL_ZERO,
2088 		.extra2		= SYSCTL_TWO_HUNDRED,
2089 	},
2090 #ifdef CONFIG_NUMA
2091 	{
2092 		.procname	= "numa_stat",
2093 		.data		= &sysctl_vm_numa_stat,
2094 		.maxlen		= sizeof(int),
2095 		.mode		= 0644,
2096 		.proc_handler	= sysctl_vm_numa_stat_handler,
2097 		.extra1		= SYSCTL_ZERO,
2098 		.extra2		= SYSCTL_ONE,
2099 	},
2100 #endif
2101 	{
2102 		.procname	= "drop_caches",
2103 		.data		= &sysctl_drop_caches,
2104 		.maxlen		= sizeof(int),
2105 		.mode		= 0200,
2106 		.proc_handler	= drop_caches_sysctl_handler,
2107 		.extra1		= SYSCTL_ONE,
2108 		.extra2		= SYSCTL_FOUR,
2109 	},
2110 	{
2111 		.procname	= "page_lock_unfairness",
2112 		.data		= &sysctl_page_lock_unfairness,
2113 		.maxlen		= sizeof(sysctl_page_lock_unfairness),
2114 		.mode		= 0644,
2115 		.proc_handler	= proc_dointvec_minmax,
2116 		.extra1		= SYSCTL_ZERO,
2117 	},
2118 #ifdef CONFIG_MMU
2119 	{
2120 		.procname	= "max_map_count",
2121 		.data		= &sysctl_max_map_count,
2122 		.maxlen		= sizeof(sysctl_max_map_count),
2123 		.mode		= 0644,
2124 		.proc_handler	= proc_dointvec_minmax,
2125 		.extra1		= SYSCTL_ZERO,
2126 	},
2127 #else
2128 	{
2129 		.procname	= "nr_trim_pages",
2130 		.data		= &sysctl_nr_trim_pages,
2131 		.maxlen		= sizeof(sysctl_nr_trim_pages),
2132 		.mode		= 0644,
2133 		.proc_handler	= proc_dointvec_minmax,
2134 		.extra1		= SYSCTL_ZERO,
2135 	},
2136 #endif
2137 	{
2138 		.procname	= "vfs_cache_pressure",
2139 		.data		= &sysctl_vfs_cache_pressure,
2140 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
2141 		.mode		= 0644,
2142 		.proc_handler	= proc_dointvec_minmax,
2143 		.extra1		= SYSCTL_ZERO,
2144 	},
2145 #if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
2146     defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
2147 	{
2148 		.procname	= "legacy_va_layout",
2149 		.data		= &sysctl_legacy_va_layout,
2150 		.maxlen		= sizeof(sysctl_legacy_va_layout),
2151 		.mode		= 0644,
2152 		.proc_handler	= proc_dointvec_minmax,
2153 		.extra1		= SYSCTL_ZERO,
2154 	},
2155 #endif
2156 #ifdef CONFIG_NUMA
2157 	{
2158 		.procname	= "zone_reclaim_mode",
2159 		.data		= &node_reclaim_mode,
2160 		.maxlen		= sizeof(node_reclaim_mode),
2161 		.mode		= 0644,
2162 		.proc_handler	= proc_dointvec_minmax,
2163 		.extra1		= SYSCTL_ZERO,
2164 	},
2165 #endif
2166 #ifdef CONFIG_SMP
2167 	{
2168 		.procname	= "stat_interval",
2169 		.data		= &sysctl_stat_interval,
2170 		.maxlen		= sizeof(sysctl_stat_interval),
2171 		.mode		= 0644,
2172 		.proc_handler	= proc_dointvec_jiffies,
2173 	},
2174 	{
2175 		.procname	= "stat_refresh",
2176 		.data		= NULL,
2177 		.maxlen		= 0,
2178 		.mode		= 0600,
2179 		.proc_handler	= vmstat_refresh,
2180 	},
2181 #endif
2182 #ifdef CONFIG_MMU
2183 	{
2184 		.procname	= "mmap_min_addr",
2185 		.data		= &dac_mmap_min_addr,
2186 		.maxlen		= sizeof(unsigned long),
2187 		.mode		= 0644,
2188 		.proc_handler	= mmap_min_addr_handler,
2189 	},
2190 #endif
2191 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
2192    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
2193 	{
2194 		.procname	= "vdso_enabled",
2195 #ifdef CONFIG_X86_32
2196 		.data		= &vdso32_enabled,
2197 		.maxlen		= sizeof(vdso32_enabled),
2198 #else
2199 		.data		= &vdso_enabled,
2200 		.maxlen		= sizeof(vdso_enabled),
2201 #endif
2202 		.mode		= 0644,
2203 		.proc_handler	= proc_dointvec,
2204 		.extra1		= SYSCTL_ZERO,
2205 	},
2206 #endif
2207 	{
2208 		.procname	= "user_reserve_kbytes",
2209 		.data		= &sysctl_user_reserve_kbytes,
2210 		.maxlen		= sizeof(sysctl_user_reserve_kbytes),
2211 		.mode		= 0644,
2212 		.proc_handler	= proc_doulongvec_minmax,
2213 	},
2214 	{
2215 		.procname	= "admin_reserve_kbytes",
2216 		.data		= &sysctl_admin_reserve_kbytes,
2217 		.maxlen		= sizeof(sysctl_admin_reserve_kbytes),
2218 		.mode		= 0644,
2219 		.proc_handler	= proc_doulongvec_minmax,
2220 	},
2221 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
2222 	{
2223 		.procname	= "mmap_rnd_bits",
2224 		.data		= &mmap_rnd_bits,
2225 		.maxlen		= sizeof(mmap_rnd_bits),
2226 		.mode		= 0600,
2227 		.proc_handler	= proc_dointvec_minmax,
2228 		.extra1		= (void *)&mmap_rnd_bits_min,
2229 		.extra2		= (void *)&mmap_rnd_bits_max,
2230 	},
2231 #endif
2232 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
2233 	{
2234 		.procname	= "mmap_rnd_compat_bits",
2235 		.data		= &mmap_rnd_compat_bits,
2236 		.maxlen		= sizeof(mmap_rnd_compat_bits),
2237 		.mode		= 0600,
2238 		.proc_handler	= proc_dointvec_minmax,
2239 		.extra1		= (void *)&mmap_rnd_compat_bits_min,
2240 		.extra2		= (void *)&mmap_rnd_compat_bits_max,
2241 	},
2242 #endif
2243 	{ }
2244 };
2245 
2246 int __init sysctl_init_bases(void)
2247 {
2248 	register_sysctl_init("kernel", kern_table);
2249 	register_sysctl_init("vm", vm_table);
2250 
2251 	return 0;
2252 }
2253 #endif /* CONFIG_SYSCTL */
2254 /*
2255  * No sense putting this after each symbol definition, twice,
2256  * exception granted :-)
2257  */
2258 EXPORT_SYMBOL(proc_dobool);
2259 EXPORT_SYMBOL(proc_dointvec);
2260 EXPORT_SYMBOL(proc_douintvec);
2261 EXPORT_SYMBOL(proc_dointvec_jiffies);
2262 EXPORT_SYMBOL(proc_dointvec_minmax);
2263 EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
2264 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2265 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2266 EXPORT_SYMBOL(proc_dostring);
2267 EXPORT_SYMBOL(proc_doulongvec_minmax);
2268 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2269 EXPORT_SYMBOL(proc_do_large_bitmap);
2270