xref: /linux/kernel/sysctl.c (revision 5860800e8696d2cbbd1a0dd60b433549d176e668)
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/compaction.h>
46 #include <linux/hugetlb.h>
47 #include <linux/initrd.h>
48 #include <linux/key.h>
49 #include <linux/times.h>
50 #include <linux/limits.h>
51 #include <linux/dcache.h>
52 #include <linux/syscalls.h>
53 #include <linux/vmstat.h>
54 #include <linux/nfs_fs.h>
55 #include <linux/acpi.h>
56 #include <linux/reboot.h>
57 #include <linux/ftrace.h>
58 #include <linux/perf_event.h>
59 #include <linux/oom.h>
60 #include <linux/kmod.h>
61 #include <linux/capability.h>
62 #include <linux/binfmts.h>
63 #include <linux/sched/sysctl.h>
64 #include <linux/mount.h>
65 #include <linux/userfaultfd_k.h>
66 #include <linux/pid.h>
67 
68 #include "../lib/kstrtox.h"
69 
70 #include <linux/uaccess.h>
71 #include <asm/processor.h>
72 
73 #ifdef CONFIG_X86
74 #include <asm/nmi.h>
75 #include <asm/stacktrace.h>
76 #include <asm/io.h>
77 #endif
78 #ifdef CONFIG_SPARC
79 #include <asm/setup.h>
80 #endif
81 #ifdef CONFIG_RT_MUTEXES
82 #include <linux/rtmutex.h>
83 #endif
84 
85 #if defined(CONFIG_SYSCTL)
86 
87 /* Constants used for minimum and  maximum */
88 
89 #ifdef CONFIG_PERF_EVENTS
90 static const int six_hundred_forty_kb = 640 * 1024;
91 #endif
92 
93 
94 static const int ngroups_max = NGROUPS_MAX;
95 static const int cap_last_cap = CAP_LAST_CAP;
96 
97 #ifdef CONFIG_PROC_SYSCTL
98 
99 /**
100  * enum sysctl_writes_mode - supported sysctl write modes
101  *
102  * @SYSCTL_WRITES_LEGACY: each write syscall must fully contain the sysctl value
103  *	to be written, and multiple writes on the same sysctl file descriptor
104  *	will rewrite the sysctl value, regardless of file position. No warning
105  *	is issued when the initial position is not 0.
106  * @SYSCTL_WRITES_WARN: same as above but warn when the initial file position is
107  *	not 0.
108  * @SYSCTL_WRITES_STRICT: writes to numeric sysctl entries must always be at
109  *	file position 0 and the value must be fully contained in the buffer
110  *	sent to the write syscall. If dealing with strings respect the file
111  *	position, but restrict this to the max length of the buffer, anything
112  *	passed the max length will be ignored. Multiple writes will append
113  *	to the buffer.
114  *
115  * These write modes control how current file position affects the behavior of
116  * updating sysctl values through the proc interface on each write.
117  */
118 enum sysctl_writes_mode {
119 	SYSCTL_WRITES_LEGACY		= -1,
120 	SYSCTL_WRITES_WARN		= 0,
121 	SYSCTL_WRITES_STRICT		= 1,
122 };
123 
124 static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
125 #endif /* CONFIG_PROC_SYSCTL */
126 
127 #if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
128     defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
129 int sysctl_legacy_va_layout;
130 #endif
131 
132 #ifdef CONFIG_COMPACTION
133 /* min_extfrag_threshold is SYSCTL_ZERO */;
134 static const int max_extfrag_threshold = 1000;
135 #endif
136 
137 #endif /* CONFIG_SYSCTL */
138 
139 /*
140  * /proc/sys support
141  */
142 
143 #ifdef CONFIG_PROC_SYSCTL
144 
145 static int _proc_do_string(char *data, int maxlen, int write,
146 		char *buffer, size_t *lenp, loff_t *ppos)
147 {
148 	size_t len;
149 	char c, *p;
150 
151 	if (!data || !maxlen || !*lenp) {
152 		*lenp = 0;
153 		return 0;
154 	}
155 
156 	if (write) {
157 		if (sysctl_writes_strict == SYSCTL_WRITES_STRICT) {
158 			/* Only continue writes not past the end of buffer. */
159 			len = strlen(data);
160 			if (len > maxlen - 1)
161 				len = maxlen - 1;
162 
163 			if (*ppos > len)
164 				return 0;
165 			len = *ppos;
166 		} else {
167 			/* Start writing from beginning of buffer. */
168 			len = 0;
169 		}
170 
171 		*ppos += *lenp;
172 		p = buffer;
173 		while ((p - buffer) < *lenp && len < maxlen - 1) {
174 			c = *(p++);
175 			if (c == 0 || c == '\n')
176 				break;
177 			data[len++] = c;
178 		}
179 		data[len] = 0;
180 	} else {
181 		len = strlen(data);
182 		if (len > maxlen)
183 			len = maxlen;
184 
185 		if (*ppos > len) {
186 			*lenp = 0;
187 			return 0;
188 		}
189 
190 		data += *ppos;
191 		len  -= *ppos;
192 
193 		if (len > *lenp)
194 			len = *lenp;
195 		if (len)
196 			memcpy(buffer, data, len);
197 		if (len < *lenp) {
198 			buffer[len] = '\n';
199 			len++;
200 		}
201 		*lenp = len;
202 		*ppos += len;
203 	}
204 	return 0;
205 }
206 
207 static void warn_sysctl_write(struct ctl_table *table)
208 {
209 	pr_warn_once("%s wrote to %s when file position was not 0!\n"
210 		"This will not be supported in the future. To silence this\n"
211 		"warning, set kernel.sysctl_writes_strict = -1\n",
212 		current->comm, table->procname);
213 }
214 
215 /**
216  * proc_first_pos_non_zero_ignore - check if first position is allowed
217  * @ppos: file position
218  * @table: the sysctl table
219  *
220  * Returns true if the first position is non-zero and the sysctl_writes_strict
221  * mode indicates this is not allowed for numeric input types. String proc
222  * handlers can ignore the return value.
223  */
224 static bool proc_first_pos_non_zero_ignore(loff_t *ppos,
225 					   struct ctl_table *table)
226 {
227 	if (!*ppos)
228 		return false;
229 
230 	switch (sysctl_writes_strict) {
231 	case SYSCTL_WRITES_STRICT:
232 		return true;
233 	case SYSCTL_WRITES_WARN:
234 		warn_sysctl_write(table);
235 		return false;
236 	default:
237 		return false;
238 	}
239 }
240 
241 /**
242  * proc_dostring - read a string sysctl
243  * @table: the sysctl table
244  * @write: %TRUE if this is a write to the sysctl file
245  * @buffer: the user buffer
246  * @lenp: the size of the user buffer
247  * @ppos: file position
248  *
249  * Reads/writes a string from/to the user buffer. If the kernel
250  * buffer provided is not large enough to hold the string, the
251  * string is truncated. The copied string is %NULL-terminated.
252  * If the string is being read by the user process, it is copied
253  * and a newline '\n' is added. It is truncated if the buffer is
254  * not large enough.
255  *
256  * Returns 0 on success.
257  */
258 int proc_dostring(struct ctl_table *table, int write,
259 		  void *buffer, size_t *lenp, loff_t *ppos)
260 {
261 	if (write)
262 		proc_first_pos_non_zero_ignore(ppos, table);
263 
264 	return _proc_do_string(table->data, table->maxlen, write, buffer, lenp,
265 			ppos);
266 }
267 
268 static size_t proc_skip_spaces(char **buf)
269 {
270 	size_t ret;
271 	char *tmp = skip_spaces(*buf);
272 	ret = tmp - *buf;
273 	*buf = tmp;
274 	return ret;
275 }
276 
277 static void proc_skip_char(char **buf, size_t *size, const char v)
278 {
279 	while (*size) {
280 		if (**buf != v)
281 			break;
282 		(*size)--;
283 		(*buf)++;
284 	}
285 }
286 
287 /**
288  * strtoul_lenient - parse an ASCII formatted integer from a buffer and only
289  *                   fail on overflow
290  *
291  * @cp: kernel buffer containing the string to parse
292  * @endp: pointer to store the trailing characters
293  * @base: the base to use
294  * @res: where the parsed integer will be stored
295  *
296  * In case of success 0 is returned and @res will contain the parsed integer,
297  * @endp will hold any trailing characters.
298  * This function will fail the parse on overflow. If there wasn't an overflow
299  * the function will defer the decision what characters count as invalid to the
300  * caller.
301  */
302 static int strtoul_lenient(const char *cp, char **endp, unsigned int base,
303 			   unsigned long *res)
304 {
305 	unsigned long long result;
306 	unsigned int rv;
307 
308 	cp = _parse_integer_fixup_radix(cp, &base);
309 	rv = _parse_integer(cp, base, &result);
310 	if ((rv & KSTRTOX_OVERFLOW) || (result != (unsigned long)result))
311 		return -ERANGE;
312 
313 	cp += rv;
314 
315 	if (endp)
316 		*endp = (char *)cp;
317 
318 	*res = (unsigned long)result;
319 	return 0;
320 }
321 
322 #define TMPBUFLEN 22
323 /**
324  * proc_get_long - reads an ASCII formatted integer from a user buffer
325  *
326  * @buf: a kernel buffer
327  * @size: size of the kernel buffer
328  * @val: this is where the number will be stored
329  * @neg: set to %TRUE if number is negative
330  * @perm_tr: a vector which contains the allowed trailers
331  * @perm_tr_len: size of the perm_tr vector
332  * @tr: pointer to store the trailer character
333  *
334  * In case of success %0 is returned and @buf and @size are updated with
335  * the amount of bytes read. If @tr is non-NULL and a trailing
336  * character exists (size is non-zero after returning from this
337  * function), @tr is updated with the trailing character.
338  */
339 static int proc_get_long(char **buf, size_t *size,
340 			  unsigned long *val, bool *neg,
341 			  const char *perm_tr, unsigned perm_tr_len, char *tr)
342 {
343 	int len;
344 	char *p, tmp[TMPBUFLEN];
345 
346 	if (!*size)
347 		return -EINVAL;
348 
349 	len = *size;
350 	if (len > TMPBUFLEN - 1)
351 		len = TMPBUFLEN - 1;
352 
353 	memcpy(tmp, *buf, len);
354 
355 	tmp[len] = 0;
356 	p = tmp;
357 	if (*p == '-' && *size > 1) {
358 		*neg = true;
359 		p++;
360 	} else
361 		*neg = false;
362 	if (!isdigit(*p))
363 		return -EINVAL;
364 
365 	if (strtoul_lenient(p, &p, 0, val))
366 		return -EINVAL;
367 
368 	len = p - tmp;
369 
370 	/* We don't know if the next char is whitespace thus we may accept
371 	 * invalid integers (e.g. 1234...a) or two integers instead of one
372 	 * (e.g. 123...1). So lets not allow such large numbers. */
373 	if (len == TMPBUFLEN - 1)
374 		return -EINVAL;
375 
376 	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
377 		return -EINVAL;
378 
379 	if (tr && (len < *size))
380 		*tr = *p;
381 
382 	*buf += len;
383 	*size -= len;
384 
385 	return 0;
386 }
387 
388 /**
389  * proc_put_long - converts an integer to a decimal ASCII formatted string
390  *
391  * @buf: the user buffer
392  * @size: the size of the user buffer
393  * @val: the integer to be converted
394  * @neg: sign of the number, %TRUE for negative
395  *
396  * In case of success @buf and @size are updated with the amount of bytes
397  * written.
398  */
399 static void proc_put_long(void **buf, size_t *size, unsigned long val, bool neg)
400 {
401 	int len;
402 	char tmp[TMPBUFLEN], *p = tmp;
403 
404 	sprintf(p, "%s%lu", neg ? "-" : "", val);
405 	len = strlen(tmp);
406 	if (len > *size)
407 		len = *size;
408 	memcpy(*buf, tmp, len);
409 	*size -= len;
410 	*buf += len;
411 }
412 #undef TMPBUFLEN
413 
414 static void proc_put_char(void **buf, size_t *size, char c)
415 {
416 	if (*size) {
417 		char **buffer = (char **)buf;
418 		**buffer = c;
419 
420 		(*size)--;
421 		(*buffer)++;
422 		*buf = *buffer;
423 	}
424 }
425 
426 static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp,
427 				int *valp,
428 				int write, void *data)
429 {
430 	if (write) {
431 		*(bool *)valp = *lvalp;
432 	} else {
433 		int val = *(bool *)valp;
434 
435 		*lvalp = (unsigned long)val;
436 		*negp = false;
437 	}
438 	return 0;
439 }
440 
441 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
442 				 int *valp,
443 				 int write, void *data)
444 {
445 	if (write) {
446 		if (*negp) {
447 			if (*lvalp > (unsigned long) INT_MAX + 1)
448 				return -EINVAL;
449 			*valp = -*lvalp;
450 		} else {
451 			if (*lvalp > (unsigned long) INT_MAX)
452 				return -EINVAL;
453 			*valp = *lvalp;
454 		}
455 	} else {
456 		int val = *valp;
457 		if (val < 0) {
458 			*negp = true;
459 			*lvalp = -(unsigned long)val;
460 		} else {
461 			*negp = false;
462 			*lvalp = (unsigned long)val;
463 		}
464 	}
465 	return 0;
466 }
467 
468 static int do_proc_douintvec_conv(unsigned long *lvalp,
469 				  unsigned int *valp,
470 				  int write, void *data)
471 {
472 	if (write) {
473 		if (*lvalp > UINT_MAX)
474 			return -EINVAL;
475 		*valp = *lvalp;
476 	} else {
477 		unsigned int val = *valp;
478 		*lvalp = (unsigned long)val;
479 	}
480 	return 0;
481 }
482 
483 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
484 
485 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
486 		  int write, void *buffer,
487 		  size_t *lenp, loff_t *ppos,
488 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
489 			      int write, void *data),
490 		  void *data)
491 {
492 	int *i, vleft, first = 1, err = 0;
493 	size_t left;
494 	char *p;
495 
496 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
497 		*lenp = 0;
498 		return 0;
499 	}
500 
501 	i = (int *) tbl_data;
502 	vleft = table->maxlen / sizeof(*i);
503 	left = *lenp;
504 
505 	if (!conv)
506 		conv = do_proc_dointvec_conv;
507 
508 	if (write) {
509 		if (proc_first_pos_non_zero_ignore(ppos, table))
510 			goto out;
511 
512 		if (left > PAGE_SIZE - 1)
513 			left = PAGE_SIZE - 1;
514 		p = buffer;
515 	}
516 
517 	for (; left && vleft--; i++, first=0) {
518 		unsigned long lval;
519 		bool neg;
520 
521 		if (write) {
522 			left -= proc_skip_spaces(&p);
523 
524 			if (!left)
525 				break;
526 			err = proc_get_long(&p, &left, &lval, &neg,
527 					     proc_wspace_sep,
528 					     sizeof(proc_wspace_sep), NULL);
529 			if (err)
530 				break;
531 			if (conv(&neg, &lval, i, 1, data)) {
532 				err = -EINVAL;
533 				break;
534 			}
535 		} else {
536 			if (conv(&neg, &lval, i, 0, data)) {
537 				err = -EINVAL;
538 				break;
539 			}
540 			if (!first)
541 				proc_put_char(&buffer, &left, '\t');
542 			proc_put_long(&buffer, &left, lval, neg);
543 		}
544 	}
545 
546 	if (!write && !first && left && !err)
547 		proc_put_char(&buffer, &left, '\n');
548 	if (write && !err && left)
549 		left -= proc_skip_spaces(&p);
550 	if (write && first)
551 		return err ? : -EINVAL;
552 	*lenp -= left;
553 out:
554 	*ppos += *lenp;
555 	return err;
556 }
557 
558 static int do_proc_dointvec(struct ctl_table *table, int write,
559 		  void *buffer, size_t *lenp, loff_t *ppos,
560 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
561 			      int write, void *data),
562 		  void *data)
563 {
564 	return __do_proc_dointvec(table->data, table, write,
565 			buffer, lenp, ppos, conv, data);
566 }
567 
568 static int do_proc_douintvec_w(unsigned int *tbl_data,
569 			       struct ctl_table *table,
570 			       void *buffer,
571 			       size_t *lenp, loff_t *ppos,
572 			       int (*conv)(unsigned long *lvalp,
573 					   unsigned int *valp,
574 					   int write, void *data),
575 			       void *data)
576 {
577 	unsigned long lval;
578 	int err = 0;
579 	size_t left;
580 	bool neg;
581 	char *p = buffer;
582 
583 	left = *lenp;
584 
585 	if (proc_first_pos_non_zero_ignore(ppos, table))
586 		goto bail_early;
587 
588 	if (left > PAGE_SIZE - 1)
589 		left = PAGE_SIZE - 1;
590 
591 	left -= proc_skip_spaces(&p);
592 	if (!left) {
593 		err = -EINVAL;
594 		goto out_free;
595 	}
596 
597 	err = proc_get_long(&p, &left, &lval, &neg,
598 			     proc_wspace_sep,
599 			     sizeof(proc_wspace_sep), NULL);
600 	if (err || neg) {
601 		err = -EINVAL;
602 		goto out_free;
603 	}
604 
605 	if (conv(&lval, tbl_data, 1, data)) {
606 		err = -EINVAL;
607 		goto out_free;
608 	}
609 
610 	if (!err && left)
611 		left -= proc_skip_spaces(&p);
612 
613 out_free:
614 	if (err)
615 		return -EINVAL;
616 
617 	return 0;
618 
619 	/* This is in keeping with old __do_proc_dointvec() */
620 bail_early:
621 	*ppos += *lenp;
622 	return err;
623 }
624 
625 static int do_proc_douintvec_r(unsigned int *tbl_data, void *buffer,
626 			       size_t *lenp, loff_t *ppos,
627 			       int (*conv)(unsigned long *lvalp,
628 					   unsigned int *valp,
629 					   int write, void *data),
630 			       void *data)
631 {
632 	unsigned long lval;
633 	int err = 0;
634 	size_t left;
635 
636 	left = *lenp;
637 
638 	if (conv(&lval, tbl_data, 0, data)) {
639 		err = -EINVAL;
640 		goto out;
641 	}
642 
643 	proc_put_long(&buffer, &left, lval, false);
644 	if (!left)
645 		goto out;
646 
647 	proc_put_char(&buffer, &left, '\n');
648 
649 out:
650 	*lenp -= left;
651 	*ppos += *lenp;
652 
653 	return err;
654 }
655 
656 static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table,
657 			       int write, void *buffer,
658 			       size_t *lenp, loff_t *ppos,
659 			       int (*conv)(unsigned long *lvalp,
660 					   unsigned int *valp,
661 					   int write, void *data),
662 			       void *data)
663 {
664 	unsigned int *i, vleft;
665 
666 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
667 		*lenp = 0;
668 		return 0;
669 	}
670 
671 	i = (unsigned int *) tbl_data;
672 	vleft = table->maxlen / sizeof(*i);
673 
674 	/*
675 	 * Arrays are not supported, keep this simple. *Do not* add
676 	 * support for them.
677 	 */
678 	if (vleft != 1) {
679 		*lenp = 0;
680 		return -EINVAL;
681 	}
682 
683 	if (!conv)
684 		conv = do_proc_douintvec_conv;
685 
686 	if (write)
687 		return do_proc_douintvec_w(i, table, buffer, lenp, ppos,
688 					   conv, data);
689 	return do_proc_douintvec_r(i, buffer, lenp, ppos, conv, data);
690 }
691 
692 int do_proc_douintvec(struct ctl_table *table, int write,
693 		      void *buffer, size_t *lenp, loff_t *ppos,
694 		      int (*conv)(unsigned long *lvalp,
695 				  unsigned int *valp,
696 				  int write, void *data),
697 		      void *data)
698 {
699 	return __do_proc_douintvec(table->data, table, write,
700 				   buffer, lenp, ppos, conv, data);
701 }
702 
703 /**
704  * proc_dobool - read/write a bool
705  * @table: the sysctl table
706  * @write: %TRUE if this is a write to the sysctl file
707  * @buffer: the user buffer
708  * @lenp: the size of the user buffer
709  * @ppos: file position
710  *
711  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
712  * values from/to the user buffer, treated as an ASCII string.
713  *
714  * Returns 0 on success.
715  */
716 int proc_dobool(struct ctl_table *table, int write, void *buffer,
717 		size_t *lenp, loff_t *ppos)
718 {
719 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
720 				do_proc_dobool_conv, NULL);
721 }
722 
723 /**
724  * proc_dointvec - read a vector of integers
725  * @table: the sysctl table
726  * @write: %TRUE if this is a write to the sysctl file
727  * @buffer: the user buffer
728  * @lenp: the size of the user buffer
729  * @ppos: file position
730  *
731  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
732  * values from/to the user buffer, treated as an ASCII string.
733  *
734  * Returns 0 on success.
735  */
736 int proc_dointvec(struct ctl_table *table, int write, void *buffer,
737 		  size_t *lenp, loff_t *ppos)
738 {
739 	return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL);
740 }
741 
742 #ifdef CONFIG_COMPACTION
743 static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table,
744 		int write, void *buffer, size_t *lenp, loff_t *ppos)
745 {
746 	int ret, old;
747 
748 	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || !write)
749 		return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
750 
751 	old = *(int *)table->data;
752 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
753 	if (ret)
754 		return ret;
755 	if (old != *(int *)table->data)
756 		pr_warn_once("sysctl attribute %s changed by %s[%d]\n",
757 			     table->procname, current->comm,
758 			     task_pid_nr(current));
759 	return ret;
760 }
761 #endif
762 
763 /**
764  * proc_douintvec - read a vector of unsigned integers
765  * @table: the sysctl table
766  * @write: %TRUE if this is a write to the sysctl file
767  * @buffer: the user buffer
768  * @lenp: the size of the user buffer
769  * @ppos: file position
770  *
771  * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
772  * values from/to the user buffer, treated as an ASCII string.
773  *
774  * Returns 0 on success.
775  */
776 int proc_douintvec(struct ctl_table *table, int write, void *buffer,
777 		size_t *lenp, loff_t *ppos)
778 {
779 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
780 				 do_proc_douintvec_conv, NULL);
781 }
782 
783 /*
784  * Taint values can only be increased
785  * This means we can safely use a temporary.
786  */
787 static int proc_taint(struct ctl_table *table, int write,
788 			       void *buffer, size_t *lenp, loff_t *ppos)
789 {
790 	struct ctl_table t;
791 	unsigned long tmptaint = get_taint();
792 	int err;
793 
794 	if (write && !capable(CAP_SYS_ADMIN))
795 		return -EPERM;
796 
797 	t = *table;
798 	t.data = &tmptaint;
799 	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
800 	if (err < 0)
801 		return err;
802 
803 	if (write) {
804 		int i;
805 
806 		/*
807 		 * If we are relying on panic_on_taint not producing
808 		 * false positives due to userspace input, bail out
809 		 * before setting the requested taint flags.
810 		 */
811 		if (panic_on_taint_nousertaint && (tmptaint & panic_on_taint))
812 			return -EINVAL;
813 
814 		/*
815 		 * Poor man's atomic or. Not worth adding a primitive
816 		 * to everyone's atomic.h for this
817 		 */
818 		for (i = 0; i < TAINT_FLAGS_COUNT; i++)
819 			if ((1UL << i) & tmptaint)
820 				add_taint(i, LOCKDEP_STILL_OK);
821 	}
822 
823 	return err;
824 }
825 
826 /**
827  * struct do_proc_dointvec_minmax_conv_param - proc_dointvec_minmax() range checking structure
828  * @min: pointer to minimum allowable value
829  * @max: pointer to maximum allowable value
830  *
831  * The do_proc_dointvec_minmax_conv_param structure provides the
832  * minimum and maximum values for doing range checking for those sysctl
833  * parameters that use the proc_dointvec_minmax() handler.
834  */
835 struct do_proc_dointvec_minmax_conv_param {
836 	int *min;
837 	int *max;
838 };
839 
840 static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
841 					int *valp,
842 					int write, void *data)
843 {
844 	int tmp, ret;
845 	struct do_proc_dointvec_minmax_conv_param *param = data;
846 	/*
847 	 * If writing, first do so via a temporary local int so we can
848 	 * bounds-check it before touching *valp.
849 	 */
850 	int *ip = write ? &tmp : valp;
851 
852 	ret = do_proc_dointvec_conv(negp, lvalp, ip, write, data);
853 	if (ret)
854 		return ret;
855 
856 	if (write) {
857 		if ((param->min && *param->min > tmp) ||
858 		    (param->max && *param->max < tmp))
859 			return -EINVAL;
860 		*valp = tmp;
861 	}
862 
863 	return 0;
864 }
865 
866 /**
867  * proc_dointvec_minmax - read a vector of integers with min/max values
868  * @table: the sysctl table
869  * @write: %TRUE if this is a write to the sysctl file
870  * @buffer: the user buffer
871  * @lenp: the size of the user buffer
872  * @ppos: file position
873  *
874  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
875  * values from/to the user buffer, treated as an ASCII string.
876  *
877  * This routine will ensure the values are within the range specified by
878  * table->extra1 (min) and table->extra2 (max).
879  *
880  * Returns 0 on success or -EINVAL on write when the range check fails.
881  */
882 int proc_dointvec_minmax(struct ctl_table *table, int write,
883 		  void *buffer, size_t *lenp, loff_t *ppos)
884 {
885 	struct do_proc_dointvec_minmax_conv_param param = {
886 		.min = (int *) table->extra1,
887 		.max = (int *) table->extra2,
888 	};
889 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
890 				do_proc_dointvec_minmax_conv, &param);
891 }
892 
893 /**
894  * struct do_proc_douintvec_minmax_conv_param - proc_douintvec_minmax() range checking structure
895  * @min: pointer to minimum allowable value
896  * @max: pointer to maximum allowable value
897  *
898  * The do_proc_douintvec_minmax_conv_param structure provides the
899  * minimum and maximum values for doing range checking for those sysctl
900  * parameters that use the proc_douintvec_minmax() handler.
901  */
902 struct do_proc_douintvec_minmax_conv_param {
903 	unsigned int *min;
904 	unsigned int *max;
905 };
906 
907 static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
908 					 unsigned int *valp,
909 					 int write, void *data)
910 {
911 	int ret;
912 	unsigned int tmp;
913 	struct do_proc_douintvec_minmax_conv_param *param = data;
914 	/* write via temporary local uint for bounds-checking */
915 	unsigned int *up = write ? &tmp : valp;
916 
917 	ret = do_proc_douintvec_conv(lvalp, up, write, data);
918 	if (ret)
919 		return ret;
920 
921 	if (write) {
922 		if ((param->min && *param->min > tmp) ||
923 		    (param->max && *param->max < tmp))
924 			return -ERANGE;
925 
926 		*valp = tmp;
927 	}
928 
929 	return 0;
930 }
931 
932 /**
933  * proc_douintvec_minmax - read a vector of unsigned ints with min/max values
934  * @table: the sysctl table
935  * @write: %TRUE if this is a write to the sysctl file
936  * @buffer: the user buffer
937  * @lenp: the size of the user buffer
938  * @ppos: file position
939  *
940  * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
941  * values from/to the user buffer, treated as an ASCII string. Negative
942  * strings are not allowed.
943  *
944  * This routine will ensure the values are within the range specified by
945  * table->extra1 (min) and table->extra2 (max). There is a final sanity
946  * check for UINT_MAX to avoid having to support wrap around uses from
947  * userspace.
948  *
949  * Returns 0 on success or -ERANGE on write when the range check fails.
950  */
951 int proc_douintvec_minmax(struct ctl_table *table, int write,
952 			  void *buffer, size_t *lenp, loff_t *ppos)
953 {
954 	struct do_proc_douintvec_minmax_conv_param param = {
955 		.min = (unsigned int *) table->extra1,
956 		.max = (unsigned int *) table->extra2,
957 	};
958 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
959 				 do_proc_douintvec_minmax_conv, &param);
960 }
961 
962 /**
963  * proc_dou8vec_minmax - read a vector of unsigned chars with min/max values
964  * @table: the sysctl table
965  * @write: %TRUE if this is a write to the sysctl file
966  * @buffer: the user buffer
967  * @lenp: the size of the user buffer
968  * @ppos: file position
969  *
970  * Reads/writes up to table->maxlen/sizeof(u8) unsigned chars
971  * values from/to the user buffer, treated as an ASCII string. Negative
972  * strings are not allowed.
973  *
974  * This routine will ensure the values are within the range specified by
975  * table->extra1 (min) and table->extra2 (max).
976  *
977  * Returns 0 on success or an error on write when the range check fails.
978  */
979 int proc_dou8vec_minmax(struct ctl_table *table, int write,
980 			void *buffer, size_t *lenp, loff_t *ppos)
981 {
982 	struct ctl_table tmp;
983 	unsigned int min = 0, max = 255U, val;
984 	u8 *data = table->data;
985 	struct do_proc_douintvec_minmax_conv_param param = {
986 		.min = &min,
987 		.max = &max,
988 	};
989 	int res;
990 
991 	/* Do not support arrays yet. */
992 	if (table->maxlen != sizeof(u8))
993 		return -EINVAL;
994 
995 	if (table->extra1) {
996 		min = *(unsigned int *) table->extra1;
997 		if (min > 255U)
998 			return -EINVAL;
999 	}
1000 	if (table->extra2) {
1001 		max = *(unsigned int *) table->extra2;
1002 		if (max > 255U)
1003 			return -EINVAL;
1004 	}
1005 
1006 	tmp = *table;
1007 
1008 	tmp.maxlen = sizeof(val);
1009 	tmp.data = &val;
1010 	val = *data;
1011 	res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
1012 				do_proc_douintvec_minmax_conv, &param);
1013 	if (res)
1014 		return res;
1015 	if (write)
1016 		*data = val;
1017 	return 0;
1018 }
1019 EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
1020 
1021 #ifdef CONFIG_MAGIC_SYSRQ
1022 static int sysrq_sysctl_handler(struct ctl_table *table, int write,
1023 				void *buffer, size_t *lenp, loff_t *ppos)
1024 {
1025 	int tmp, ret;
1026 
1027 	tmp = sysrq_mask();
1028 
1029 	ret = __do_proc_dointvec(&tmp, table, write, buffer,
1030 			       lenp, ppos, NULL, NULL);
1031 	if (ret || !write)
1032 		return ret;
1033 
1034 	if (write)
1035 		sysrq_toggle_support(tmp);
1036 
1037 	return 0;
1038 }
1039 #endif
1040 
1041 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table,
1042 		int write, void *buffer, size_t *lenp, loff_t *ppos,
1043 		unsigned long convmul, unsigned long convdiv)
1044 {
1045 	unsigned long *i, *min, *max;
1046 	int vleft, first = 1, err = 0;
1047 	size_t left;
1048 	char *p;
1049 
1050 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
1051 		*lenp = 0;
1052 		return 0;
1053 	}
1054 
1055 	i = (unsigned long *) data;
1056 	min = (unsigned long *) table->extra1;
1057 	max = (unsigned long *) table->extra2;
1058 	vleft = table->maxlen / sizeof(unsigned long);
1059 	left = *lenp;
1060 
1061 	if (write) {
1062 		if (proc_first_pos_non_zero_ignore(ppos, table))
1063 			goto out;
1064 
1065 		if (left > PAGE_SIZE - 1)
1066 			left = PAGE_SIZE - 1;
1067 		p = buffer;
1068 	}
1069 
1070 	for (; left && vleft--; i++, first = 0) {
1071 		unsigned long val;
1072 
1073 		if (write) {
1074 			bool neg;
1075 
1076 			left -= proc_skip_spaces(&p);
1077 			if (!left)
1078 				break;
1079 
1080 			err = proc_get_long(&p, &left, &val, &neg,
1081 					     proc_wspace_sep,
1082 					     sizeof(proc_wspace_sep), NULL);
1083 			if (err || neg) {
1084 				err = -EINVAL;
1085 				break;
1086 			}
1087 
1088 			val = convmul * val / convdiv;
1089 			if ((min && val < *min) || (max && val > *max)) {
1090 				err = -EINVAL;
1091 				break;
1092 			}
1093 			*i = val;
1094 		} else {
1095 			val = convdiv * (*i) / convmul;
1096 			if (!first)
1097 				proc_put_char(&buffer, &left, '\t');
1098 			proc_put_long(&buffer, &left, val, false);
1099 		}
1100 	}
1101 
1102 	if (!write && !first && left && !err)
1103 		proc_put_char(&buffer, &left, '\n');
1104 	if (write && !err)
1105 		left -= proc_skip_spaces(&p);
1106 	if (write && first)
1107 		return err ? : -EINVAL;
1108 	*lenp -= left;
1109 out:
1110 	*ppos += *lenp;
1111 	return err;
1112 }
1113 
1114 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
1115 		void *buffer, size_t *lenp, loff_t *ppos, unsigned long convmul,
1116 		unsigned long convdiv)
1117 {
1118 	return __do_proc_doulongvec_minmax(table->data, table, write,
1119 			buffer, lenp, ppos, convmul, convdiv);
1120 }
1121 
1122 /**
1123  * proc_doulongvec_minmax - read a vector of long integers with min/max values
1124  * @table: the sysctl table
1125  * @write: %TRUE if this is a write to the sysctl file
1126  * @buffer: the user buffer
1127  * @lenp: the size of the user buffer
1128  * @ppos: file position
1129  *
1130  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
1131  * values from/to the user buffer, treated as an ASCII string.
1132  *
1133  * This routine will ensure the values are within the range specified by
1134  * table->extra1 (min) and table->extra2 (max).
1135  *
1136  * Returns 0 on success.
1137  */
1138 int proc_doulongvec_minmax(struct ctl_table *table, int write,
1139 			   void *buffer, size_t *lenp, loff_t *ppos)
1140 {
1141     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
1142 }
1143 
1144 /**
1145  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
1146  * @table: the sysctl table
1147  * @write: %TRUE if this is a write to the sysctl file
1148  * @buffer: the user buffer
1149  * @lenp: the size of the user buffer
1150  * @ppos: file position
1151  *
1152  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
1153  * values from/to the user buffer, treated as an ASCII string. The values
1154  * are treated as milliseconds, and converted to jiffies when they are stored.
1155  *
1156  * This routine will ensure the values are within the range specified by
1157  * table->extra1 (min) and table->extra2 (max).
1158  *
1159  * Returns 0 on success.
1160  */
1161 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1162 				      void *buffer, size_t *lenp, loff_t *ppos)
1163 {
1164     return do_proc_doulongvec_minmax(table, write, buffer,
1165 				     lenp, ppos, HZ, 1000l);
1166 }
1167 
1168 
1169 static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
1170 					 int *valp,
1171 					 int write, void *data)
1172 {
1173 	if (write) {
1174 		if (*lvalp > INT_MAX / HZ)
1175 			return 1;
1176 		*valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
1177 	} else {
1178 		int val = *valp;
1179 		unsigned long lval;
1180 		if (val < 0) {
1181 			*negp = true;
1182 			lval = -(unsigned long)val;
1183 		} else {
1184 			*negp = false;
1185 			lval = (unsigned long)val;
1186 		}
1187 		*lvalp = lval / HZ;
1188 	}
1189 	return 0;
1190 }
1191 
1192 static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
1193 						int *valp,
1194 						int write, void *data)
1195 {
1196 	if (write) {
1197 		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
1198 			return 1;
1199 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
1200 	} else {
1201 		int val = *valp;
1202 		unsigned long lval;
1203 		if (val < 0) {
1204 			*negp = true;
1205 			lval = -(unsigned long)val;
1206 		} else {
1207 			*negp = false;
1208 			lval = (unsigned long)val;
1209 		}
1210 		*lvalp = jiffies_to_clock_t(lval);
1211 	}
1212 	return 0;
1213 }
1214 
1215 static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
1216 					    int *valp,
1217 					    int write, void *data)
1218 {
1219 	if (write) {
1220 		unsigned long jif = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
1221 
1222 		if (jif > INT_MAX)
1223 			return 1;
1224 		*valp = (int)jif;
1225 	} else {
1226 		int val = *valp;
1227 		unsigned long lval;
1228 		if (val < 0) {
1229 			*negp = true;
1230 			lval = -(unsigned long)val;
1231 		} else {
1232 			*negp = false;
1233 			lval = (unsigned long)val;
1234 		}
1235 		*lvalp = jiffies_to_msecs(lval);
1236 	}
1237 	return 0;
1238 }
1239 
1240 /**
1241  * proc_dointvec_jiffies - read a vector of integers as seconds
1242  * @table: the sysctl table
1243  * @write: %TRUE if this is a write to the sysctl file
1244  * @buffer: the user buffer
1245  * @lenp: the size of the user buffer
1246  * @ppos: file position
1247  *
1248  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1249  * values from/to the user buffer, treated as an ASCII string.
1250  * The values read are assumed to be in seconds, and are converted into
1251  * jiffies.
1252  *
1253  * Returns 0 on success.
1254  */
1255 int proc_dointvec_jiffies(struct ctl_table *table, int write,
1256 			  void *buffer, size_t *lenp, loff_t *ppos)
1257 {
1258     return do_proc_dointvec(table,write,buffer,lenp,ppos,
1259 		    	    do_proc_dointvec_jiffies_conv,NULL);
1260 }
1261 
1262 /**
1263  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
1264  * @table: the sysctl table
1265  * @write: %TRUE if this is a write to the sysctl file
1266  * @buffer: the user buffer
1267  * @lenp: the size of the user buffer
1268  * @ppos: pointer to the file position
1269  *
1270  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1271  * values from/to the user buffer, treated as an ASCII string.
1272  * The values read are assumed to be in 1/USER_HZ seconds, and
1273  * are converted into jiffies.
1274  *
1275  * Returns 0 on success.
1276  */
1277 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
1278 				 void *buffer, size_t *lenp, loff_t *ppos)
1279 {
1280     return do_proc_dointvec(table,write,buffer,lenp,ppos,
1281 		    	    do_proc_dointvec_userhz_jiffies_conv,NULL);
1282 }
1283 
1284 /**
1285  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
1286  * @table: the sysctl table
1287  * @write: %TRUE if this is a write to the sysctl file
1288  * @buffer: the user buffer
1289  * @lenp: the size of the user buffer
1290  * @ppos: file position
1291  * @ppos: the current position in the file
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 1/1000 seconds, and
1296  * are converted into jiffies.
1297  *
1298  * Returns 0 on success.
1299  */
1300 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, void *buffer,
1301 		size_t *lenp, loff_t *ppos)
1302 {
1303 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
1304 				do_proc_dointvec_ms_jiffies_conv, NULL);
1305 }
1306 
1307 static int proc_do_cad_pid(struct ctl_table *table, int write, void *buffer,
1308 		size_t *lenp, loff_t *ppos)
1309 {
1310 	struct pid *new_pid;
1311 	pid_t tmp;
1312 	int r;
1313 
1314 	tmp = pid_vnr(cad_pid);
1315 
1316 	r = __do_proc_dointvec(&tmp, table, write, buffer,
1317 			       lenp, ppos, NULL, NULL);
1318 	if (r || !write)
1319 		return r;
1320 
1321 	new_pid = find_get_pid(tmp);
1322 	if (!new_pid)
1323 		return -ESRCH;
1324 
1325 	put_pid(xchg(&cad_pid, new_pid));
1326 	return 0;
1327 }
1328 
1329 /**
1330  * proc_do_large_bitmap - read/write from/to a large bitmap
1331  * @table: the sysctl table
1332  * @write: %TRUE if this is a write to the sysctl file
1333  * @buffer: the user buffer
1334  * @lenp: the size of the user buffer
1335  * @ppos: file position
1336  *
1337  * The bitmap is stored at table->data and the bitmap length (in bits)
1338  * in table->maxlen.
1339  *
1340  * We use a range comma separated format (e.g. 1,3-4,10-10) so that
1341  * large bitmaps may be represented in a compact manner. Writing into
1342  * the file will clear the bitmap then update it with the given input.
1343  *
1344  * Returns 0 on success.
1345  */
1346 int proc_do_large_bitmap(struct ctl_table *table, int write,
1347 			 void *buffer, size_t *lenp, loff_t *ppos)
1348 {
1349 	int err = 0;
1350 	size_t left = *lenp;
1351 	unsigned long bitmap_len = table->maxlen;
1352 	unsigned long *bitmap = *(unsigned long **) table->data;
1353 	unsigned long *tmp_bitmap = NULL;
1354 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
1355 
1356 	if (!bitmap || !bitmap_len || !left || (*ppos && !write)) {
1357 		*lenp = 0;
1358 		return 0;
1359 	}
1360 
1361 	if (write) {
1362 		char *p = buffer;
1363 		size_t skipped = 0;
1364 
1365 		if (left > PAGE_SIZE - 1) {
1366 			left = PAGE_SIZE - 1;
1367 			/* How much of the buffer we'll skip this pass */
1368 			skipped = *lenp - left;
1369 		}
1370 
1371 		tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL);
1372 		if (!tmp_bitmap)
1373 			return -ENOMEM;
1374 		proc_skip_char(&p, &left, '\n');
1375 		while (!err && left) {
1376 			unsigned long val_a, val_b;
1377 			bool neg;
1378 			size_t saved_left;
1379 
1380 			/* In case we stop parsing mid-number, we can reset */
1381 			saved_left = left;
1382 			err = proc_get_long(&p, &left, &val_a, &neg, tr_a,
1383 					     sizeof(tr_a), &c);
1384 			/*
1385 			 * If we consumed the entirety of a truncated buffer or
1386 			 * only one char is left (may be a "-"), then stop here,
1387 			 * reset, & come back for more.
1388 			 */
1389 			if ((left <= 1) && skipped) {
1390 				left = saved_left;
1391 				break;
1392 			}
1393 
1394 			if (err)
1395 				break;
1396 			if (val_a >= bitmap_len || neg) {
1397 				err = -EINVAL;
1398 				break;
1399 			}
1400 
1401 			val_b = val_a;
1402 			if (left) {
1403 				p++;
1404 				left--;
1405 			}
1406 
1407 			if (c == '-') {
1408 				err = proc_get_long(&p, &left, &val_b,
1409 						     &neg, tr_b, sizeof(tr_b),
1410 						     &c);
1411 				/*
1412 				 * If we consumed all of a truncated buffer or
1413 				 * then stop here, reset, & come back for more.
1414 				 */
1415 				if (!left && skipped) {
1416 					left = saved_left;
1417 					break;
1418 				}
1419 
1420 				if (err)
1421 					break;
1422 				if (val_b >= bitmap_len || neg ||
1423 				    val_a > val_b) {
1424 					err = -EINVAL;
1425 					break;
1426 				}
1427 				if (left) {
1428 					p++;
1429 					left--;
1430 				}
1431 			}
1432 
1433 			bitmap_set(tmp_bitmap, val_a, val_b - val_a + 1);
1434 			proc_skip_char(&p, &left, '\n');
1435 		}
1436 		left += skipped;
1437 	} else {
1438 		unsigned long bit_a, bit_b = 0;
1439 		bool first = 1;
1440 
1441 		while (left) {
1442 			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
1443 			if (bit_a >= bitmap_len)
1444 				break;
1445 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
1446 						   bit_a + 1) - 1;
1447 
1448 			if (!first)
1449 				proc_put_char(&buffer, &left, ',');
1450 			proc_put_long(&buffer, &left, bit_a, false);
1451 			if (bit_a != bit_b) {
1452 				proc_put_char(&buffer, &left, '-');
1453 				proc_put_long(&buffer, &left, bit_b, false);
1454 			}
1455 
1456 			first = 0; bit_b++;
1457 		}
1458 		proc_put_char(&buffer, &left, '\n');
1459 	}
1460 
1461 	if (!err) {
1462 		if (write) {
1463 			if (*ppos)
1464 				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
1465 			else
1466 				bitmap_copy(bitmap, tmp_bitmap, bitmap_len);
1467 		}
1468 		*lenp -= left;
1469 		*ppos += *lenp;
1470 	}
1471 
1472 	bitmap_free(tmp_bitmap);
1473 	return err;
1474 }
1475 
1476 #else /* CONFIG_PROC_SYSCTL */
1477 
1478 int proc_dostring(struct ctl_table *table, int write,
1479 		  void *buffer, size_t *lenp, loff_t *ppos)
1480 {
1481 	return -ENOSYS;
1482 }
1483 
1484 int proc_dobool(struct ctl_table *table, int write,
1485 		void *buffer, size_t *lenp, loff_t *ppos)
1486 {
1487 	return -ENOSYS;
1488 }
1489 
1490 int proc_dointvec(struct ctl_table *table, int write,
1491 		  void *buffer, size_t *lenp, loff_t *ppos)
1492 {
1493 	return -ENOSYS;
1494 }
1495 
1496 int proc_douintvec(struct ctl_table *table, int write,
1497 		  void *buffer, size_t *lenp, loff_t *ppos)
1498 {
1499 	return -ENOSYS;
1500 }
1501 
1502 int proc_dointvec_minmax(struct ctl_table *table, int write,
1503 		    void *buffer, size_t *lenp, loff_t *ppos)
1504 {
1505 	return -ENOSYS;
1506 }
1507 
1508 int proc_douintvec_minmax(struct ctl_table *table, int write,
1509 			  void *buffer, size_t *lenp, loff_t *ppos)
1510 {
1511 	return -ENOSYS;
1512 }
1513 
1514 int proc_dou8vec_minmax(struct ctl_table *table, int write,
1515 			void *buffer, size_t *lenp, loff_t *ppos)
1516 {
1517 	return -ENOSYS;
1518 }
1519 
1520 int proc_dointvec_jiffies(struct ctl_table *table, int write,
1521 		    void *buffer, size_t *lenp, loff_t *ppos)
1522 {
1523 	return -ENOSYS;
1524 }
1525 
1526 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
1527 		    void *buffer, size_t *lenp, loff_t *ppos)
1528 {
1529 	return -ENOSYS;
1530 }
1531 
1532 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
1533 			     void *buffer, size_t *lenp, loff_t *ppos)
1534 {
1535 	return -ENOSYS;
1536 }
1537 
1538 int proc_doulongvec_minmax(struct ctl_table *table, int write,
1539 		    void *buffer, size_t *lenp, loff_t *ppos)
1540 {
1541 	return -ENOSYS;
1542 }
1543 
1544 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1545 				      void *buffer, size_t *lenp, loff_t *ppos)
1546 {
1547 	return -ENOSYS;
1548 }
1549 
1550 int proc_do_large_bitmap(struct ctl_table *table, int write,
1551 			 void *buffer, size_t *lenp, loff_t *ppos)
1552 {
1553 	return -ENOSYS;
1554 }
1555 
1556 #endif /* CONFIG_PROC_SYSCTL */
1557 
1558 #if defined(CONFIG_SYSCTL)
1559 int proc_do_static_key(struct ctl_table *table, int write,
1560 		       void *buffer, size_t *lenp, loff_t *ppos)
1561 {
1562 	struct static_key *key = (struct static_key *)table->data;
1563 	static DEFINE_MUTEX(static_key_mutex);
1564 	int val, ret;
1565 	struct ctl_table tmp = {
1566 		.data   = &val,
1567 		.maxlen = sizeof(val),
1568 		.mode   = table->mode,
1569 		.extra1 = SYSCTL_ZERO,
1570 		.extra2 = SYSCTL_ONE,
1571 	};
1572 
1573 	if (write && !capable(CAP_SYS_ADMIN))
1574 		return -EPERM;
1575 
1576 	mutex_lock(&static_key_mutex);
1577 	val = static_key_enabled(key);
1578 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
1579 	if (write && !ret) {
1580 		if (val)
1581 			static_key_enable(key);
1582 		else
1583 			static_key_disable(key);
1584 	}
1585 	mutex_unlock(&static_key_mutex);
1586 	return ret;
1587 }
1588 
1589 static struct ctl_table kern_table[] = {
1590 #ifdef CONFIG_NUMA_BALANCING
1591 	{
1592 		.procname	= "numa_balancing",
1593 		.data		= NULL, /* filled in by handler */
1594 		.maxlen		= sizeof(unsigned int),
1595 		.mode		= 0644,
1596 		.proc_handler	= sysctl_numa_balancing,
1597 		.extra1		= SYSCTL_ZERO,
1598 		.extra2		= SYSCTL_FOUR,
1599 	},
1600 #endif /* CONFIG_NUMA_BALANCING */
1601 	{
1602 		.procname	= "panic",
1603 		.data		= &panic_timeout,
1604 		.maxlen		= sizeof(int),
1605 		.mode		= 0644,
1606 		.proc_handler	= proc_dointvec,
1607 	},
1608 #ifdef CONFIG_PROC_SYSCTL
1609 	{
1610 		.procname	= "tainted",
1611 		.maxlen 	= sizeof(long),
1612 		.mode		= 0644,
1613 		.proc_handler	= proc_taint,
1614 	},
1615 	{
1616 		.procname	= "sysctl_writes_strict",
1617 		.data		= &sysctl_writes_strict,
1618 		.maxlen		= sizeof(int),
1619 		.mode		= 0644,
1620 		.proc_handler	= proc_dointvec_minmax,
1621 		.extra1		= SYSCTL_NEG_ONE,
1622 		.extra2		= SYSCTL_ONE,
1623 	},
1624 #endif
1625 	{
1626 		.procname	= "print-fatal-signals",
1627 		.data		= &print_fatal_signals,
1628 		.maxlen		= sizeof(int),
1629 		.mode		= 0644,
1630 		.proc_handler	= proc_dointvec,
1631 	},
1632 #ifdef CONFIG_SPARC
1633 	{
1634 		.procname	= "reboot-cmd",
1635 		.data		= reboot_command,
1636 		.maxlen		= 256,
1637 		.mode		= 0644,
1638 		.proc_handler	= proc_dostring,
1639 	},
1640 	{
1641 		.procname	= "stop-a",
1642 		.data		= &stop_a_enabled,
1643 		.maxlen		= sizeof (int),
1644 		.mode		= 0644,
1645 		.proc_handler	= proc_dointvec,
1646 	},
1647 	{
1648 		.procname	= "scons-poweroff",
1649 		.data		= &scons_pwroff,
1650 		.maxlen		= sizeof (int),
1651 		.mode		= 0644,
1652 		.proc_handler	= proc_dointvec,
1653 	},
1654 #endif
1655 #ifdef CONFIG_SPARC64
1656 	{
1657 		.procname	= "tsb-ratio",
1658 		.data		= &sysctl_tsb_ratio,
1659 		.maxlen		= sizeof (int),
1660 		.mode		= 0644,
1661 		.proc_handler	= proc_dointvec,
1662 	},
1663 #endif
1664 #ifdef CONFIG_PARISC
1665 	{
1666 		.procname	= "soft-power",
1667 		.data		= &pwrsw_enabled,
1668 		.maxlen		= sizeof (int),
1669 		.mode		= 0644,
1670 		.proc_handler	= proc_dointvec,
1671 	},
1672 #endif
1673 #ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
1674 	{
1675 		.procname	= "unaligned-trap",
1676 		.data		= &unaligned_enabled,
1677 		.maxlen		= sizeof (int),
1678 		.mode		= 0644,
1679 		.proc_handler	= proc_dointvec,
1680 	},
1681 #endif
1682 #ifdef CONFIG_STACK_TRACER
1683 	{
1684 		.procname	= "stack_tracer_enabled",
1685 		.data		= &stack_tracer_enabled,
1686 		.maxlen		= sizeof(int),
1687 		.mode		= 0644,
1688 		.proc_handler	= stack_trace_sysctl,
1689 	},
1690 #endif
1691 #ifdef CONFIG_TRACING
1692 	{
1693 		.procname	= "ftrace_dump_on_oops",
1694 		.data		= &ftrace_dump_on_oops,
1695 		.maxlen		= sizeof(int),
1696 		.mode		= 0644,
1697 		.proc_handler	= proc_dointvec,
1698 	},
1699 	{
1700 		.procname	= "traceoff_on_warning",
1701 		.data		= &__disable_trace_on_warning,
1702 		.maxlen		= sizeof(__disable_trace_on_warning),
1703 		.mode		= 0644,
1704 		.proc_handler	= proc_dointvec,
1705 	},
1706 	{
1707 		.procname	= "tracepoint_printk",
1708 		.data		= &tracepoint_printk,
1709 		.maxlen		= sizeof(tracepoint_printk),
1710 		.mode		= 0644,
1711 		.proc_handler	= tracepoint_printk_sysctl,
1712 	},
1713 #endif
1714 #ifdef CONFIG_MODULES
1715 	{
1716 		.procname	= "modprobe",
1717 		.data		= &modprobe_path,
1718 		.maxlen		= KMOD_PATH_LEN,
1719 		.mode		= 0644,
1720 		.proc_handler	= proc_dostring,
1721 	},
1722 	{
1723 		.procname	= "modules_disabled",
1724 		.data		= &modules_disabled,
1725 		.maxlen		= sizeof(int),
1726 		.mode		= 0644,
1727 		/* only handle a transition from default "0" to "1" */
1728 		.proc_handler	= proc_dointvec_minmax,
1729 		.extra1		= SYSCTL_ONE,
1730 		.extra2		= SYSCTL_ONE,
1731 	},
1732 #endif
1733 #ifdef CONFIG_UEVENT_HELPER
1734 	{
1735 		.procname	= "hotplug",
1736 		.data		= &uevent_helper,
1737 		.maxlen		= UEVENT_HELPER_PATH_LEN,
1738 		.mode		= 0644,
1739 		.proc_handler	= proc_dostring,
1740 	},
1741 #endif
1742 #ifdef CONFIG_MAGIC_SYSRQ
1743 	{
1744 		.procname	= "sysrq",
1745 		.data		= NULL,
1746 		.maxlen		= sizeof (int),
1747 		.mode		= 0644,
1748 		.proc_handler	= sysrq_sysctl_handler,
1749 	},
1750 #endif
1751 #ifdef CONFIG_PROC_SYSCTL
1752 	{
1753 		.procname	= "cad_pid",
1754 		.data		= NULL,
1755 		.maxlen		= sizeof (int),
1756 		.mode		= 0600,
1757 		.proc_handler	= proc_do_cad_pid,
1758 	},
1759 #endif
1760 	{
1761 		.procname	= "threads-max",
1762 		.data		= NULL,
1763 		.maxlen		= sizeof(int),
1764 		.mode		= 0644,
1765 		.proc_handler	= sysctl_max_threads,
1766 	},
1767 	{
1768 		.procname	= "usermodehelper",
1769 		.mode		= 0555,
1770 		.child		= usermodehelper_table,
1771 	},
1772 	{
1773 		.procname	= "overflowuid",
1774 		.data		= &overflowuid,
1775 		.maxlen		= sizeof(int),
1776 		.mode		= 0644,
1777 		.proc_handler	= proc_dointvec_minmax,
1778 		.extra1		= SYSCTL_ZERO,
1779 		.extra2		= SYSCTL_MAXOLDUID,
1780 	},
1781 	{
1782 		.procname	= "overflowgid",
1783 		.data		= &overflowgid,
1784 		.maxlen		= sizeof(int),
1785 		.mode		= 0644,
1786 		.proc_handler	= proc_dointvec_minmax,
1787 		.extra1		= SYSCTL_ZERO,
1788 		.extra2		= SYSCTL_MAXOLDUID,
1789 	},
1790 #ifdef CONFIG_S390
1791 	{
1792 		.procname	= "userprocess_debug",
1793 		.data		= &show_unhandled_signals,
1794 		.maxlen		= sizeof(int),
1795 		.mode		= 0644,
1796 		.proc_handler	= proc_dointvec,
1797 	},
1798 #endif
1799 	{
1800 		.procname	= "pid_max",
1801 		.data		= &pid_max,
1802 		.maxlen		= sizeof (int),
1803 		.mode		= 0644,
1804 		.proc_handler	= proc_dointvec_minmax,
1805 		.extra1		= &pid_max_min,
1806 		.extra2		= &pid_max_max,
1807 	},
1808 	{
1809 		.procname	= "panic_on_oops",
1810 		.data		= &panic_on_oops,
1811 		.maxlen		= sizeof(int),
1812 		.mode		= 0644,
1813 		.proc_handler	= proc_dointvec,
1814 	},
1815 	{
1816 		.procname	= "panic_print",
1817 		.data		= &panic_print,
1818 		.maxlen		= sizeof(unsigned long),
1819 		.mode		= 0644,
1820 		.proc_handler	= proc_doulongvec_minmax,
1821 	},
1822 	{
1823 		.procname	= "ngroups_max",
1824 		.data		= (void *)&ngroups_max,
1825 		.maxlen		= sizeof (int),
1826 		.mode		= 0444,
1827 		.proc_handler	= proc_dointvec,
1828 	},
1829 	{
1830 		.procname	= "cap_last_cap",
1831 		.data		= (void *)&cap_last_cap,
1832 		.maxlen		= sizeof(int),
1833 		.mode		= 0444,
1834 		.proc_handler	= proc_dointvec,
1835 	},
1836 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
1837 	{
1838 		.procname       = "unknown_nmi_panic",
1839 		.data           = &unknown_nmi_panic,
1840 		.maxlen         = sizeof (int),
1841 		.mode           = 0644,
1842 		.proc_handler   = proc_dointvec,
1843 	},
1844 #endif
1845 
1846 #if (defined(CONFIG_X86_32) || defined(CONFIG_PARISC)) && \
1847 	defined(CONFIG_DEBUG_STACKOVERFLOW)
1848 	{
1849 		.procname	= "panic_on_stackoverflow",
1850 		.data		= &sysctl_panic_on_stackoverflow,
1851 		.maxlen		= sizeof(int),
1852 		.mode		= 0644,
1853 		.proc_handler	= proc_dointvec,
1854 	},
1855 #endif
1856 #if defined(CONFIG_X86)
1857 	{
1858 		.procname	= "panic_on_unrecovered_nmi",
1859 		.data		= &panic_on_unrecovered_nmi,
1860 		.maxlen		= sizeof(int),
1861 		.mode		= 0644,
1862 		.proc_handler	= proc_dointvec,
1863 	},
1864 	{
1865 		.procname	= "panic_on_io_nmi",
1866 		.data		= &panic_on_io_nmi,
1867 		.maxlen		= sizeof(int),
1868 		.mode		= 0644,
1869 		.proc_handler	= proc_dointvec,
1870 	},
1871 	{
1872 		.procname	= "bootloader_type",
1873 		.data		= &bootloader_type,
1874 		.maxlen		= sizeof (int),
1875 		.mode		= 0444,
1876 		.proc_handler	= proc_dointvec,
1877 	},
1878 	{
1879 		.procname	= "bootloader_version",
1880 		.data		= &bootloader_version,
1881 		.maxlen		= sizeof (int),
1882 		.mode		= 0444,
1883 		.proc_handler	= proc_dointvec,
1884 	},
1885 	{
1886 		.procname	= "io_delay_type",
1887 		.data		= &io_delay_type,
1888 		.maxlen		= sizeof(int),
1889 		.mode		= 0644,
1890 		.proc_handler	= proc_dointvec,
1891 	},
1892 #endif
1893 #if defined(CONFIG_MMU)
1894 	{
1895 		.procname	= "randomize_va_space",
1896 		.data		= &randomize_va_space,
1897 		.maxlen		= sizeof(int),
1898 		.mode		= 0644,
1899 		.proc_handler	= proc_dointvec,
1900 	},
1901 #endif
1902 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
1903 	{
1904 		.procname	= "spin_retry",
1905 		.data		= &spin_retry,
1906 		.maxlen		= sizeof (int),
1907 		.mode		= 0644,
1908 		.proc_handler	= proc_dointvec,
1909 	},
1910 #endif
1911 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
1912 	{
1913 		.procname	= "acpi_video_flags",
1914 		.data		= &acpi_realmode_flags,
1915 		.maxlen		= sizeof (unsigned long),
1916 		.mode		= 0644,
1917 		.proc_handler	= proc_doulongvec_minmax,
1918 	},
1919 #endif
1920 #ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
1921 	{
1922 		.procname	= "ignore-unaligned-usertrap",
1923 		.data		= &no_unaligned_warning,
1924 		.maxlen		= sizeof (int),
1925 		.mode		= 0644,
1926 		.proc_handler	= proc_dointvec,
1927 	},
1928 #endif
1929 #ifdef CONFIG_IA64
1930 	{
1931 		.procname	= "unaligned-dump-stack",
1932 		.data		= &unaligned_dump_stack,
1933 		.maxlen		= sizeof (int),
1934 		.mode		= 0644,
1935 		.proc_handler	= proc_dointvec,
1936 	},
1937 #endif
1938 #ifdef CONFIG_RT_MUTEXES
1939 	{
1940 		.procname	= "max_lock_depth",
1941 		.data		= &max_lock_depth,
1942 		.maxlen		= sizeof(int),
1943 		.mode		= 0644,
1944 		.proc_handler	= proc_dointvec,
1945 	},
1946 #endif
1947 #ifdef CONFIG_KEYS
1948 	{
1949 		.procname	= "keys",
1950 		.mode		= 0555,
1951 		.child		= key_sysctls,
1952 	},
1953 #endif
1954 #ifdef CONFIG_PERF_EVENTS
1955 	/*
1956 	 * User-space scripts rely on the existence of this file
1957 	 * as a feature check for perf_events being enabled.
1958 	 *
1959 	 * So it's an ABI, do not remove!
1960 	 */
1961 	{
1962 		.procname	= "perf_event_paranoid",
1963 		.data		= &sysctl_perf_event_paranoid,
1964 		.maxlen		= sizeof(sysctl_perf_event_paranoid),
1965 		.mode		= 0644,
1966 		.proc_handler	= proc_dointvec,
1967 	},
1968 	{
1969 		.procname	= "perf_event_mlock_kb",
1970 		.data		= &sysctl_perf_event_mlock,
1971 		.maxlen		= sizeof(sysctl_perf_event_mlock),
1972 		.mode		= 0644,
1973 		.proc_handler	= proc_dointvec,
1974 	},
1975 	{
1976 		.procname	= "perf_event_max_sample_rate",
1977 		.data		= &sysctl_perf_event_sample_rate,
1978 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
1979 		.mode		= 0644,
1980 		.proc_handler	= perf_proc_update_handler,
1981 		.extra1		= SYSCTL_ONE,
1982 	},
1983 	{
1984 		.procname	= "perf_cpu_time_max_percent",
1985 		.data		= &sysctl_perf_cpu_time_max_percent,
1986 		.maxlen		= sizeof(sysctl_perf_cpu_time_max_percent),
1987 		.mode		= 0644,
1988 		.proc_handler	= perf_cpu_time_max_percent_handler,
1989 		.extra1		= SYSCTL_ZERO,
1990 		.extra2		= SYSCTL_ONE_HUNDRED,
1991 	},
1992 	{
1993 		.procname	= "perf_event_max_stack",
1994 		.data		= &sysctl_perf_event_max_stack,
1995 		.maxlen		= sizeof(sysctl_perf_event_max_stack),
1996 		.mode		= 0644,
1997 		.proc_handler	= perf_event_max_stack_handler,
1998 		.extra1		= SYSCTL_ZERO,
1999 		.extra2		= (void *)&six_hundred_forty_kb,
2000 	},
2001 	{
2002 		.procname	= "perf_event_max_contexts_per_stack",
2003 		.data		= &sysctl_perf_event_max_contexts_per_stack,
2004 		.maxlen		= sizeof(sysctl_perf_event_max_contexts_per_stack),
2005 		.mode		= 0644,
2006 		.proc_handler	= perf_event_max_stack_handler,
2007 		.extra1		= SYSCTL_ZERO,
2008 		.extra2		= SYSCTL_ONE_THOUSAND,
2009 	},
2010 #endif
2011 	{
2012 		.procname	= "panic_on_warn",
2013 		.data		= &panic_on_warn,
2014 		.maxlen		= sizeof(int),
2015 		.mode		= 0644,
2016 		.proc_handler	= proc_dointvec_minmax,
2017 		.extra1		= SYSCTL_ZERO,
2018 		.extra2		= SYSCTL_ONE,
2019 	},
2020 #if defined(CONFIG_TREE_RCU)
2021 	{
2022 		.procname	= "panic_on_rcu_stall",
2023 		.data		= &sysctl_panic_on_rcu_stall,
2024 		.maxlen		= sizeof(sysctl_panic_on_rcu_stall),
2025 		.mode		= 0644,
2026 		.proc_handler	= proc_dointvec_minmax,
2027 		.extra1		= SYSCTL_ZERO,
2028 		.extra2		= SYSCTL_ONE,
2029 	},
2030 #endif
2031 #if defined(CONFIG_TREE_RCU)
2032 	{
2033 		.procname	= "max_rcu_stall_to_panic",
2034 		.data		= &sysctl_max_rcu_stall_to_panic,
2035 		.maxlen		= sizeof(sysctl_max_rcu_stall_to_panic),
2036 		.mode		= 0644,
2037 		.proc_handler	= proc_dointvec_minmax,
2038 		.extra1		= SYSCTL_ONE,
2039 		.extra2		= SYSCTL_INT_MAX,
2040 	},
2041 #endif
2042 	{ }
2043 };
2044 
2045 static struct ctl_table vm_table[] = {
2046 	{
2047 		.procname	= "overcommit_memory",
2048 		.data		= &sysctl_overcommit_memory,
2049 		.maxlen		= sizeof(sysctl_overcommit_memory),
2050 		.mode		= 0644,
2051 		.proc_handler	= overcommit_policy_handler,
2052 		.extra1		= SYSCTL_ZERO,
2053 		.extra2		= SYSCTL_TWO,
2054 	},
2055 	{
2056 		.procname	= "overcommit_ratio",
2057 		.data		= &sysctl_overcommit_ratio,
2058 		.maxlen		= sizeof(sysctl_overcommit_ratio),
2059 		.mode		= 0644,
2060 		.proc_handler	= overcommit_ratio_handler,
2061 	},
2062 	{
2063 		.procname	= "overcommit_kbytes",
2064 		.data		= &sysctl_overcommit_kbytes,
2065 		.maxlen		= sizeof(sysctl_overcommit_kbytes),
2066 		.mode		= 0644,
2067 		.proc_handler	= overcommit_kbytes_handler,
2068 	},
2069 	{
2070 		.procname	= "page-cluster",
2071 		.data		= &page_cluster,
2072 		.maxlen		= sizeof(int),
2073 		.mode		= 0644,
2074 		.proc_handler	= proc_dointvec_minmax,
2075 		.extra1		= SYSCTL_ZERO,
2076 	},
2077 	{
2078 		.procname	= "dirtytime_expire_seconds",
2079 		.data		= &dirtytime_expire_interval,
2080 		.maxlen		= sizeof(dirtytime_expire_interval),
2081 		.mode		= 0644,
2082 		.proc_handler	= dirtytime_interval_handler,
2083 		.extra1		= SYSCTL_ZERO,
2084 	},
2085 	{
2086 		.procname	= "swappiness",
2087 		.data		= &vm_swappiness,
2088 		.maxlen		= sizeof(vm_swappiness),
2089 		.mode		= 0644,
2090 		.proc_handler	= proc_dointvec_minmax,
2091 		.extra1		= SYSCTL_ZERO,
2092 		.extra2		= SYSCTL_TWO_HUNDRED,
2093 	},
2094 #ifdef CONFIG_HUGETLB_PAGE
2095 	{
2096 		.procname	= "nr_hugepages",
2097 		.data		= NULL,
2098 		.maxlen		= sizeof(unsigned long),
2099 		.mode		= 0644,
2100 		.proc_handler	= hugetlb_sysctl_handler,
2101 	},
2102 #ifdef CONFIG_NUMA
2103 	{
2104 		.procname       = "nr_hugepages_mempolicy",
2105 		.data           = NULL,
2106 		.maxlen         = sizeof(unsigned long),
2107 		.mode           = 0644,
2108 		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
2109 	},
2110 	{
2111 		.procname		= "numa_stat",
2112 		.data			= &sysctl_vm_numa_stat,
2113 		.maxlen			= sizeof(int),
2114 		.mode			= 0644,
2115 		.proc_handler	= sysctl_vm_numa_stat_handler,
2116 		.extra1			= SYSCTL_ZERO,
2117 		.extra2			= SYSCTL_ONE,
2118 	},
2119 #endif
2120 	 {
2121 		.procname	= "hugetlb_shm_group",
2122 		.data		= &sysctl_hugetlb_shm_group,
2123 		.maxlen		= sizeof(gid_t),
2124 		.mode		= 0644,
2125 		.proc_handler	= proc_dointvec,
2126 	 },
2127 	{
2128 		.procname	= "nr_overcommit_hugepages",
2129 		.data		= NULL,
2130 		.maxlen		= sizeof(unsigned long),
2131 		.mode		= 0644,
2132 		.proc_handler	= hugetlb_overcommit_handler,
2133 	},
2134 #endif
2135 	{
2136 		.procname	= "lowmem_reserve_ratio",
2137 		.data		= &sysctl_lowmem_reserve_ratio,
2138 		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
2139 		.mode		= 0644,
2140 		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
2141 	},
2142 	{
2143 		.procname	= "drop_caches",
2144 		.data		= &sysctl_drop_caches,
2145 		.maxlen		= sizeof(int),
2146 		.mode		= 0200,
2147 		.proc_handler	= drop_caches_sysctl_handler,
2148 		.extra1		= SYSCTL_ONE,
2149 		.extra2		= SYSCTL_FOUR,
2150 	},
2151 #ifdef CONFIG_COMPACTION
2152 	{
2153 		.procname	= "compact_memory",
2154 		.data		= NULL,
2155 		.maxlen		= sizeof(int),
2156 		.mode		= 0200,
2157 		.proc_handler	= sysctl_compaction_handler,
2158 	},
2159 	{
2160 		.procname	= "compaction_proactiveness",
2161 		.data		= &sysctl_compaction_proactiveness,
2162 		.maxlen		= sizeof(sysctl_compaction_proactiveness),
2163 		.mode		= 0644,
2164 		.proc_handler	= compaction_proactiveness_sysctl_handler,
2165 		.extra1		= SYSCTL_ZERO,
2166 		.extra2		= SYSCTL_ONE_HUNDRED,
2167 	},
2168 	{
2169 		.procname	= "extfrag_threshold",
2170 		.data		= &sysctl_extfrag_threshold,
2171 		.maxlen		= sizeof(int),
2172 		.mode		= 0644,
2173 		.proc_handler	= proc_dointvec_minmax,
2174 		.extra1		= SYSCTL_ZERO,
2175 		.extra2		= (void *)&max_extfrag_threshold,
2176 	},
2177 	{
2178 		.procname	= "compact_unevictable_allowed",
2179 		.data		= &sysctl_compact_unevictable_allowed,
2180 		.maxlen		= sizeof(int),
2181 		.mode		= 0644,
2182 		.proc_handler	= proc_dointvec_minmax_warn_RT_change,
2183 		.extra1		= SYSCTL_ZERO,
2184 		.extra2		= SYSCTL_ONE,
2185 	},
2186 
2187 #endif /* CONFIG_COMPACTION */
2188 	{
2189 		.procname	= "min_free_kbytes",
2190 		.data		= &min_free_kbytes,
2191 		.maxlen		= sizeof(min_free_kbytes),
2192 		.mode		= 0644,
2193 		.proc_handler	= min_free_kbytes_sysctl_handler,
2194 		.extra1		= SYSCTL_ZERO,
2195 	},
2196 	{
2197 		.procname	= "watermark_boost_factor",
2198 		.data		= &watermark_boost_factor,
2199 		.maxlen		= sizeof(watermark_boost_factor),
2200 		.mode		= 0644,
2201 		.proc_handler	= proc_dointvec_minmax,
2202 		.extra1		= SYSCTL_ZERO,
2203 	},
2204 	{
2205 		.procname	= "watermark_scale_factor",
2206 		.data		= &watermark_scale_factor,
2207 		.maxlen		= sizeof(watermark_scale_factor),
2208 		.mode		= 0644,
2209 		.proc_handler	= watermark_scale_factor_sysctl_handler,
2210 		.extra1		= SYSCTL_ONE,
2211 		.extra2		= SYSCTL_THREE_THOUSAND,
2212 	},
2213 	{
2214 		.procname	= "percpu_pagelist_high_fraction",
2215 		.data		= &percpu_pagelist_high_fraction,
2216 		.maxlen		= sizeof(percpu_pagelist_high_fraction),
2217 		.mode		= 0644,
2218 		.proc_handler	= percpu_pagelist_high_fraction_sysctl_handler,
2219 		.extra1		= SYSCTL_ZERO,
2220 	},
2221 	{
2222 		.procname	= "page_lock_unfairness",
2223 		.data		= &sysctl_page_lock_unfairness,
2224 		.maxlen		= sizeof(sysctl_page_lock_unfairness),
2225 		.mode		= 0644,
2226 		.proc_handler	= proc_dointvec_minmax,
2227 		.extra1		= SYSCTL_ZERO,
2228 	},
2229 #ifdef CONFIG_MMU
2230 	{
2231 		.procname	= "max_map_count",
2232 		.data		= &sysctl_max_map_count,
2233 		.maxlen		= sizeof(sysctl_max_map_count),
2234 		.mode		= 0644,
2235 		.proc_handler	= proc_dointvec_minmax,
2236 		.extra1		= SYSCTL_ZERO,
2237 	},
2238 #else
2239 	{
2240 		.procname	= "nr_trim_pages",
2241 		.data		= &sysctl_nr_trim_pages,
2242 		.maxlen		= sizeof(sysctl_nr_trim_pages),
2243 		.mode		= 0644,
2244 		.proc_handler	= proc_dointvec_minmax,
2245 		.extra1		= SYSCTL_ZERO,
2246 	},
2247 #endif
2248 	{
2249 		.procname	= "vfs_cache_pressure",
2250 		.data		= &sysctl_vfs_cache_pressure,
2251 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
2252 		.mode		= 0644,
2253 		.proc_handler	= proc_dointvec_minmax,
2254 		.extra1		= SYSCTL_ZERO,
2255 	},
2256 #if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
2257     defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
2258 	{
2259 		.procname	= "legacy_va_layout",
2260 		.data		= &sysctl_legacy_va_layout,
2261 		.maxlen		= sizeof(sysctl_legacy_va_layout),
2262 		.mode		= 0644,
2263 		.proc_handler	= proc_dointvec_minmax,
2264 		.extra1		= SYSCTL_ZERO,
2265 	},
2266 #endif
2267 #ifdef CONFIG_NUMA
2268 	{
2269 		.procname	= "zone_reclaim_mode",
2270 		.data		= &node_reclaim_mode,
2271 		.maxlen		= sizeof(node_reclaim_mode),
2272 		.mode		= 0644,
2273 		.proc_handler	= proc_dointvec_minmax,
2274 		.extra1		= SYSCTL_ZERO,
2275 	},
2276 	{
2277 		.procname	= "min_unmapped_ratio",
2278 		.data		= &sysctl_min_unmapped_ratio,
2279 		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
2280 		.mode		= 0644,
2281 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
2282 		.extra1		= SYSCTL_ZERO,
2283 		.extra2		= SYSCTL_ONE_HUNDRED,
2284 	},
2285 	{
2286 		.procname	= "min_slab_ratio",
2287 		.data		= &sysctl_min_slab_ratio,
2288 		.maxlen		= sizeof(sysctl_min_slab_ratio),
2289 		.mode		= 0644,
2290 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
2291 		.extra1		= SYSCTL_ZERO,
2292 		.extra2		= SYSCTL_ONE_HUNDRED,
2293 	},
2294 #endif
2295 #ifdef CONFIG_SMP
2296 	{
2297 		.procname	= "stat_interval",
2298 		.data		= &sysctl_stat_interval,
2299 		.maxlen		= sizeof(sysctl_stat_interval),
2300 		.mode		= 0644,
2301 		.proc_handler	= proc_dointvec_jiffies,
2302 	},
2303 	{
2304 		.procname	= "stat_refresh",
2305 		.data		= NULL,
2306 		.maxlen		= 0,
2307 		.mode		= 0600,
2308 		.proc_handler	= vmstat_refresh,
2309 	},
2310 #endif
2311 #ifdef CONFIG_MMU
2312 	{
2313 		.procname	= "mmap_min_addr",
2314 		.data		= &dac_mmap_min_addr,
2315 		.maxlen		= sizeof(unsigned long),
2316 		.mode		= 0644,
2317 		.proc_handler	= mmap_min_addr_handler,
2318 	},
2319 #endif
2320 #ifdef CONFIG_NUMA
2321 	{
2322 		.procname	= "numa_zonelist_order",
2323 		.data		= &numa_zonelist_order,
2324 		.maxlen		= NUMA_ZONELIST_ORDER_LEN,
2325 		.mode		= 0644,
2326 		.proc_handler	= numa_zonelist_order_handler,
2327 	},
2328 #endif
2329 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
2330    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
2331 	{
2332 		.procname	= "vdso_enabled",
2333 #ifdef CONFIG_X86_32
2334 		.data		= &vdso32_enabled,
2335 		.maxlen		= sizeof(vdso32_enabled),
2336 #else
2337 		.data		= &vdso_enabled,
2338 		.maxlen		= sizeof(vdso_enabled),
2339 #endif
2340 		.mode		= 0644,
2341 		.proc_handler	= proc_dointvec,
2342 		.extra1		= SYSCTL_ZERO,
2343 	},
2344 #endif
2345 #ifdef CONFIG_MEMORY_FAILURE
2346 	{
2347 		.procname	= "memory_failure_early_kill",
2348 		.data		= &sysctl_memory_failure_early_kill,
2349 		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
2350 		.mode		= 0644,
2351 		.proc_handler	= proc_dointvec_minmax,
2352 		.extra1		= SYSCTL_ZERO,
2353 		.extra2		= SYSCTL_ONE,
2354 	},
2355 	{
2356 		.procname	= "memory_failure_recovery",
2357 		.data		= &sysctl_memory_failure_recovery,
2358 		.maxlen		= sizeof(sysctl_memory_failure_recovery),
2359 		.mode		= 0644,
2360 		.proc_handler	= proc_dointvec_minmax,
2361 		.extra1		= SYSCTL_ZERO,
2362 		.extra2		= SYSCTL_ONE,
2363 	},
2364 #endif
2365 	{
2366 		.procname	= "user_reserve_kbytes",
2367 		.data		= &sysctl_user_reserve_kbytes,
2368 		.maxlen		= sizeof(sysctl_user_reserve_kbytes),
2369 		.mode		= 0644,
2370 		.proc_handler	= proc_doulongvec_minmax,
2371 	},
2372 	{
2373 		.procname	= "admin_reserve_kbytes",
2374 		.data		= &sysctl_admin_reserve_kbytes,
2375 		.maxlen		= sizeof(sysctl_admin_reserve_kbytes),
2376 		.mode		= 0644,
2377 		.proc_handler	= proc_doulongvec_minmax,
2378 	},
2379 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
2380 	{
2381 		.procname	= "mmap_rnd_bits",
2382 		.data		= &mmap_rnd_bits,
2383 		.maxlen		= sizeof(mmap_rnd_bits),
2384 		.mode		= 0600,
2385 		.proc_handler	= proc_dointvec_minmax,
2386 		.extra1		= (void *)&mmap_rnd_bits_min,
2387 		.extra2		= (void *)&mmap_rnd_bits_max,
2388 	},
2389 #endif
2390 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
2391 	{
2392 		.procname	= "mmap_rnd_compat_bits",
2393 		.data		= &mmap_rnd_compat_bits,
2394 		.maxlen		= sizeof(mmap_rnd_compat_bits),
2395 		.mode		= 0600,
2396 		.proc_handler	= proc_dointvec_minmax,
2397 		.extra1		= (void *)&mmap_rnd_compat_bits_min,
2398 		.extra2		= (void *)&mmap_rnd_compat_bits_max,
2399 	},
2400 #endif
2401 #ifdef CONFIG_USERFAULTFD
2402 	{
2403 		.procname	= "unprivileged_userfaultfd",
2404 		.data		= &sysctl_unprivileged_userfaultfd,
2405 		.maxlen		= sizeof(sysctl_unprivileged_userfaultfd),
2406 		.mode		= 0644,
2407 		.proc_handler	= proc_dointvec_minmax,
2408 		.extra1		= SYSCTL_ZERO,
2409 		.extra2		= SYSCTL_ONE,
2410 	},
2411 #endif
2412 	{ }
2413 };
2414 
2415 static struct ctl_table debug_table[] = {
2416 #ifdef CONFIG_SYSCTL_EXCEPTION_TRACE
2417 	{
2418 		.procname	= "exception-trace",
2419 		.data		= &show_unhandled_signals,
2420 		.maxlen		= sizeof(int),
2421 		.mode		= 0644,
2422 		.proc_handler	= proc_dointvec
2423 	},
2424 #endif
2425 	{ }
2426 };
2427 
2428 static struct ctl_table dev_table[] = {
2429 	{ }
2430 };
2431 
2432 DECLARE_SYSCTL_BASE(kernel, kern_table);
2433 DECLARE_SYSCTL_BASE(vm, vm_table);
2434 DECLARE_SYSCTL_BASE(debug, debug_table);
2435 DECLARE_SYSCTL_BASE(dev, dev_table);
2436 
2437 int __init sysctl_init_bases(void)
2438 {
2439 	register_sysctl_base(kernel);
2440 	register_sysctl_base(vm);
2441 	register_sysctl_base(debug);
2442 	register_sysctl_base(dev);
2443 
2444 	return 0;
2445 }
2446 #endif /* CONFIG_SYSCTL */
2447 /*
2448  * No sense putting this after each symbol definition, twice,
2449  * exception granted :-)
2450  */
2451 EXPORT_SYMBOL(proc_dobool);
2452 EXPORT_SYMBOL(proc_dointvec);
2453 EXPORT_SYMBOL(proc_douintvec);
2454 EXPORT_SYMBOL(proc_dointvec_jiffies);
2455 EXPORT_SYMBOL(proc_dointvec_minmax);
2456 EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
2457 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2458 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2459 EXPORT_SYMBOL(proc_dostring);
2460 EXPORT_SYMBOL(proc_doulongvec_minmax);
2461 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2462 EXPORT_SYMBOL(proc_do_large_bitmap);
2463