xref: /openbmc/linux/kernel/sysctl.c (revision e847c767)
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 /* shared constants to be used in various sysctls */
86 const int sysctl_vals[] = { 0, 1, 2, 3, 4, 100, 200, 1000, 3000, INT_MAX, 65535, -1 };
87 EXPORT_SYMBOL(sysctl_vals);
88 
89 const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX };
90 EXPORT_SYMBOL_GPL(sysctl_long_vals);
91 
92 #if defined(CONFIG_SYSCTL)
93 
94 /* Constants used for minimum and maximum */
95 
96 #ifdef CONFIG_PERF_EVENTS
97 static const int six_hundred_forty_kb = 640 * 1024;
98 #endif
99 
100 
101 static const int ngroups_max = NGROUPS_MAX;
102 static const int cap_last_cap = CAP_LAST_CAP;
103 
104 #ifdef CONFIG_PROC_SYSCTL
105 
106 /**
107  * enum sysctl_writes_mode - supported sysctl write modes
108  *
109  * @SYSCTL_WRITES_LEGACY: each write syscall must fully contain the sysctl value
110  *	to be written, and multiple writes on the same sysctl file descriptor
111  *	will rewrite the sysctl value, regardless of file position. No warning
112  *	is issued when the initial position is not 0.
113  * @SYSCTL_WRITES_WARN: same as above but warn when the initial file position is
114  *	not 0.
115  * @SYSCTL_WRITES_STRICT: writes to numeric sysctl entries must always be at
116  *	file position 0 and the value must be fully contained in the buffer
117  *	sent to the write syscall. If dealing with strings respect the file
118  *	position, but restrict this to the max length of the buffer, anything
119  *	passed the max length will be ignored. Multiple writes will append
120  *	to the buffer.
121  *
122  * These write modes control how current file position affects the behavior of
123  * updating sysctl values through the proc interface on each write.
124  */
125 enum sysctl_writes_mode {
126 	SYSCTL_WRITES_LEGACY		= -1,
127 	SYSCTL_WRITES_WARN		= 0,
128 	SYSCTL_WRITES_STRICT		= 1,
129 };
130 
131 static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
132 #endif /* CONFIG_PROC_SYSCTL */
133 
134 #if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
135     defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
136 int sysctl_legacy_va_layout;
137 #endif
138 
139 #endif /* CONFIG_SYSCTL */
140 
141 /*
142  * /proc/sys support
143  */
144 
145 #ifdef CONFIG_PROC_SYSCTL
146 
147 static int _proc_do_string(char *data, int maxlen, int write,
148 		char *buffer, size_t *lenp, loff_t *ppos)
149 {
150 	size_t len;
151 	char c, *p;
152 
153 	if (!data || !maxlen || !*lenp) {
154 		*lenp = 0;
155 		return 0;
156 	}
157 
158 	if (write) {
159 		if (sysctl_writes_strict == SYSCTL_WRITES_STRICT) {
160 			/* Only continue writes not past the end of buffer. */
161 			len = strlen(data);
162 			if (len > maxlen - 1)
163 				len = maxlen - 1;
164 
165 			if (*ppos > len)
166 				return 0;
167 			len = *ppos;
168 		} else {
169 			/* Start writing from beginning of buffer. */
170 			len = 0;
171 		}
172 
173 		*ppos += *lenp;
174 		p = buffer;
175 		while ((p - buffer) < *lenp && len < maxlen - 1) {
176 			c = *(p++);
177 			if (c == 0 || c == '\n')
178 				break;
179 			data[len++] = c;
180 		}
181 		data[len] = 0;
182 	} else {
183 		len = strlen(data);
184 		if (len > maxlen)
185 			len = maxlen;
186 
187 		if (*ppos > len) {
188 			*lenp = 0;
189 			return 0;
190 		}
191 
192 		data += *ppos;
193 		len  -= *ppos;
194 
195 		if (len > *lenp)
196 			len = *lenp;
197 		if (len)
198 			memcpy(buffer, data, len);
199 		if (len < *lenp) {
200 			buffer[len] = '\n';
201 			len++;
202 		}
203 		*lenp = len;
204 		*ppos += len;
205 	}
206 	return 0;
207 }
208 
209 static void warn_sysctl_write(struct ctl_table *table)
210 {
211 	pr_warn_once("%s wrote to %s when file position was not 0!\n"
212 		"This will not be supported in the future. To silence this\n"
213 		"warning, set kernel.sysctl_writes_strict = -1\n",
214 		current->comm, table->procname);
215 }
216 
217 /**
218  * proc_first_pos_non_zero_ignore - check if first position is allowed
219  * @ppos: file position
220  * @table: the sysctl table
221  *
222  * Returns true if the first position is non-zero and the sysctl_writes_strict
223  * mode indicates this is not allowed for numeric input types. String proc
224  * handlers can ignore the return value.
225  */
226 static bool proc_first_pos_non_zero_ignore(loff_t *ppos,
227 					   struct ctl_table *table)
228 {
229 	if (!*ppos)
230 		return false;
231 
232 	switch (sysctl_writes_strict) {
233 	case SYSCTL_WRITES_STRICT:
234 		return true;
235 	case SYSCTL_WRITES_WARN:
236 		warn_sysctl_write(table);
237 		return false;
238 	default:
239 		return false;
240 	}
241 }
242 
243 /**
244  * proc_dostring - read a string sysctl
245  * @table: the sysctl table
246  * @write: %TRUE if this is a write to the sysctl file
247  * @buffer: the user buffer
248  * @lenp: the size of the user buffer
249  * @ppos: file position
250  *
251  * Reads/writes a string from/to the user buffer. If the kernel
252  * buffer provided is not large enough to hold the string, the
253  * string is truncated. The copied string is %NULL-terminated.
254  * If the string is being read by the user process, it is copied
255  * and a newline '\n' is added. It is truncated if the buffer is
256  * not large enough.
257  *
258  * Returns 0 on success.
259  */
260 int proc_dostring(struct ctl_table *table, int write,
261 		  void *buffer, size_t *lenp, loff_t *ppos)
262 {
263 	if (write)
264 		proc_first_pos_non_zero_ignore(ppos, table);
265 
266 	return _proc_do_string(table->data, table->maxlen, write, buffer, lenp,
267 			ppos);
268 }
269 
270 static void proc_skip_spaces(char **buf, size_t *size)
271 {
272 	while (*size) {
273 		if (!isspace(**buf))
274 			break;
275 		(*size)--;
276 		(*buf)++;
277 	}
278 }
279 
280 static void proc_skip_char(char **buf, size_t *size, const char v)
281 {
282 	while (*size) {
283 		if (**buf != v)
284 			break;
285 		(*size)--;
286 		(*buf)++;
287 	}
288 }
289 
290 /**
291  * strtoul_lenient - parse an ASCII formatted integer from a buffer and only
292  *                   fail on overflow
293  *
294  * @cp: kernel buffer containing the string to parse
295  * @endp: pointer to store the trailing characters
296  * @base: the base to use
297  * @res: where the parsed integer will be stored
298  *
299  * In case of success 0 is returned and @res will contain the parsed integer,
300  * @endp will hold any trailing characters.
301  * This function will fail the parse on overflow. If there wasn't an overflow
302  * the function will defer the decision what characters count as invalid to the
303  * caller.
304  */
305 static int strtoul_lenient(const char *cp, char **endp, unsigned int base,
306 			   unsigned long *res)
307 {
308 	unsigned long long result;
309 	unsigned int rv;
310 
311 	cp = _parse_integer_fixup_radix(cp, &base);
312 	rv = _parse_integer(cp, base, &result);
313 	if ((rv & KSTRTOX_OVERFLOW) || (result != (unsigned long)result))
314 		return -ERANGE;
315 
316 	cp += rv;
317 
318 	if (endp)
319 		*endp = (char *)cp;
320 
321 	*res = (unsigned long)result;
322 	return 0;
323 }
324 
325 #define TMPBUFLEN 22
326 /**
327  * proc_get_long - reads an ASCII formatted integer from a user buffer
328  *
329  * @buf: a kernel buffer
330  * @size: size of the kernel buffer
331  * @val: this is where the number will be stored
332  * @neg: set to %TRUE if number is negative
333  * @perm_tr: a vector which contains the allowed trailers
334  * @perm_tr_len: size of the perm_tr vector
335  * @tr: pointer to store the trailer character
336  *
337  * In case of success %0 is returned and @buf and @size are updated with
338  * the amount of bytes read. If @tr is non-NULL and a trailing
339  * character exists (size is non-zero after returning from this
340  * function), @tr is updated with the trailing character.
341  */
342 static int proc_get_long(char **buf, size_t *size,
343 			  unsigned long *val, bool *neg,
344 			  const char *perm_tr, unsigned perm_tr_len, char *tr)
345 {
346 	char *p, tmp[TMPBUFLEN];
347 	ssize_t len = *size;
348 
349 	if (len <= 0)
350 		return -EINVAL;
351 
352 	if (len > TMPBUFLEN - 1)
353 		len = TMPBUFLEN - 1;
354 
355 	memcpy(tmp, *buf, len);
356 
357 	tmp[len] = 0;
358 	p = tmp;
359 	if (*p == '-' && *size > 1) {
360 		*neg = true;
361 		p++;
362 	} else
363 		*neg = false;
364 	if (!isdigit(*p))
365 		return -EINVAL;
366 
367 	if (strtoul_lenient(p, &p, 0, val))
368 		return -EINVAL;
369 
370 	len = p - tmp;
371 
372 	/* We don't know if the next char is whitespace thus we may accept
373 	 * invalid integers (e.g. 1234...a) or two integers instead of one
374 	 * (e.g. 123...1). So lets not allow such large numbers. */
375 	if (len == TMPBUFLEN - 1)
376 		return -EINVAL;
377 
378 	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
379 		return -EINVAL;
380 
381 	if (tr && (len < *size))
382 		*tr = *p;
383 
384 	*buf += len;
385 	*size -= len;
386 
387 	return 0;
388 }
389 
390 /**
391  * proc_put_long - converts an integer to a decimal ASCII formatted string
392  *
393  * @buf: the user buffer
394  * @size: the size of the user buffer
395  * @val: the integer to be converted
396  * @neg: sign of the number, %TRUE for negative
397  *
398  * In case of success @buf and @size are updated with the amount of bytes
399  * written.
400  */
401 static void proc_put_long(void **buf, size_t *size, unsigned long val, bool neg)
402 {
403 	int len;
404 	char tmp[TMPBUFLEN], *p = tmp;
405 
406 	sprintf(p, "%s%lu", neg ? "-" : "", val);
407 	len = strlen(tmp);
408 	if (len > *size)
409 		len = *size;
410 	memcpy(*buf, tmp, len);
411 	*size -= len;
412 	*buf += len;
413 }
414 #undef TMPBUFLEN
415 
416 static void proc_put_char(void **buf, size_t *size, char c)
417 {
418 	if (*size) {
419 		char **buffer = (char **)buf;
420 		**buffer = c;
421 
422 		(*size)--;
423 		(*buffer)++;
424 		*buf = *buffer;
425 	}
426 }
427 
428 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
429 				 int *valp,
430 				 int write, void *data)
431 {
432 	if (write) {
433 		if (*negp) {
434 			if (*lvalp > (unsigned long) INT_MAX + 1)
435 				return -EINVAL;
436 			WRITE_ONCE(*valp, -*lvalp);
437 		} else {
438 			if (*lvalp > (unsigned long) INT_MAX)
439 				return -EINVAL;
440 			WRITE_ONCE(*valp, *lvalp);
441 		}
442 	} else {
443 		int val = READ_ONCE(*valp);
444 		if (val < 0) {
445 			*negp = true;
446 			*lvalp = -(unsigned long)val;
447 		} else {
448 			*negp = false;
449 			*lvalp = (unsigned long)val;
450 		}
451 	}
452 	return 0;
453 }
454 
455 static int do_proc_douintvec_conv(unsigned long *lvalp,
456 				  unsigned int *valp,
457 				  int write, void *data)
458 {
459 	if (write) {
460 		if (*lvalp > UINT_MAX)
461 			return -EINVAL;
462 		WRITE_ONCE(*valp, *lvalp);
463 	} else {
464 		unsigned int val = READ_ONCE(*valp);
465 		*lvalp = (unsigned long)val;
466 	}
467 	return 0;
468 }
469 
470 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
471 
472 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
473 		  int write, void *buffer,
474 		  size_t *lenp, loff_t *ppos,
475 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
476 			      int write, void *data),
477 		  void *data)
478 {
479 	int *i, vleft, first = 1, err = 0;
480 	size_t left;
481 	char *p;
482 
483 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
484 		*lenp = 0;
485 		return 0;
486 	}
487 
488 	i = (int *) tbl_data;
489 	vleft = table->maxlen / sizeof(*i);
490 	left = *lenp;
491 
492 	if (!conv)
493 		conv = do_proc_dointvec_conv;
494 
495 	if (write) {
496 		if (proc_first_pos_non_zero_ignore(ppos, table))
497 			goto out;
498 
499 		if (left > PAGE_SIZE - 1)
500 			left = PAGE_SIZE - 1;
501 		p = buffer;
502 	}
503 
504 	for (; left && vleft--; i++, first=0) {
505 		unsigned long lval;
506 		bool neg;
507 
508 		if (write) {
509 			proc_skip_spaces(&p, &left);
510 
511 			if (!left)
512 				break;
513 			err = proc_get_long(&p, &left, &lval, &neg,
514 					     proc_wspace_sep,
515 					     sizeof(proc_wspace_sep), NULL);
516 			if (err)
517 				break;
518 			if (conv(&neg, &lval, i, 1, data)) {
519 				err = -EINVAL;
520 				break;
521 			}
522 		} else {
523 			if (conv(&neg, &lval, i, 0, data)) {
524 				err = -EINVAL;
525 				break;
526 			}
527 			if (!first)
528 				proc_put_char(&buffer, &left, '\t');
529 			proc_put_long(&buffer, &left, lval, neg);
530 		}
531 	}
532 
533 	if (!write && !first && left && !err)
534 		proc_put_char(&buffer, &left, '\n');
535 	if (write && !err && left)
536 		proc_skip_spaces(&p, &left);
537 	if (write && first)
538 		return err ? : -EINVAL;
539 	*lenp -= left;
540 out:
541 	*ppos += *lenp;
542 	return err;
543 }
544 
545 static int do_proc_dointvec(struct ctl_table *table, int write,
546 		  void *buffer, size_t *lenp, loff_t *ppos,
547 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
548 			      int write, void *data),
549 		  void *data)
550 {
551 	return __do_proc_dointvec(table->data, table, write,
552 			buffer, lenp, ppos, conv, data);
553 }
554 
555 static int do_proc_douintvec_w(unsigned int *tbl_data,
556 			       struct ctl_table *table,
557 			       void *buffer,
558 			       size_t *lenp, loff_t *ppos,
559 			       int (*conv)(unsigned long *lvalp,
560 					   unsigned int *valp,
561 					   int write, void *data),
562 			       void *data)
563 {
564 	unsigned long lval;
565 	int err = 0;
566 	size_t left;
567 	bool neg;
568 	char *p = buffer;
569 
570 	left = *lenp;
571 
572 	if (proc_first_pos_non_zero_ignore(ppos, table))
573 		goto bail_early;
574 
575 	if (left > PAGE_SIZE - 1)
576 		left = PAGE_SIZE - 1;
577 
578 	proc_skip_spaces(&p, &left);
579 	if (!left) {
580 		err = -EINVAL;
581 		goto out_free;
582 	}
583 
584 	err = proc_get_long(&p, &left, &lval, &neg,
585 			     proc_wspace_sep,
586 			     sizeof(proc_wspace_sep), NULL);
587 	if (err || neg) {
588 		err = -EINVAL;
589 		goto out_free;
590 	}
591 
592 	if (conv(&lval, tbl_data, 1, data)) {
593 		err = -EINVAL;
594 		goto out_free;
595 	}
596 
597 	if (!err && left)
598 		proc_skip_spaces(&p, &left);
599 
600 out_free:
601 	if (err)
602 		return -EINVAL;
603 
604 	return 0;
605 
606 	/* This is in keeping with old __do_proc_dointvec() */
607 bail_early:
608 	*ppos += *lenp;
609 	return err;
610 }
611 
612 static int do_proc_douintvec_r(unsigned int *tbl_data, void *buffer,
613 			       size_t *lenp, loff_t *ppos,
614 			       int (*conv)(unsigned long *lvalp,
615 					   unsigned int *valp,
616 					   int write, void *data),
617 			       void *data)
618 {
619 	unsigned long lval;
620 	int err = 0;
621 	size_t left;
622 
623 	left = *lenp;
624 
625 	if (conv(&lval, tbl_data, 0, data)) {
626 		err = -EINVAL;
627 		goto out;
628 	}
629 
630 	proc_put_long(&buffer, &left, lval, false);
631 	if (!left)
632 		goto out;
633 
634 	proc_put_char(&buffer, &left, '\n');
635 
636 out:
637 	*lenp -= left;
638 	*ppos += *lenp;
639 
640 	return err;
641 }
642 
643 static int __do_proc_douintvec(void *tbl_data, struct ctl_table *table,
644 			       int write, void *buffer,
645 			       size_t *lenp, loff_t *ppos,
646 			       int (*conv)(unsigned long *lvalp,
647 					   unsigned int *valp,
648 					   int write, void *data),
649 			       void *data)
650 {
651 	unsigned int *i, vleft;
652 
653 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
654 		*lenp = 0;
655 		return 0;
656 	}
657 
658 	i = (unsigned int *) tbl_data;
659 	vleft = table->maxlen / sizeof(*i);
660 
661 	/*
662 	 * Arrays are not supported, keep this simple. *Do not* add
663 	 * support for them.
664 	 */
665 	if (vleft != 1) {
666 		*lenp = 0;
667 		return -EINVAL;
668 	}
669 
670 	if (!conv)
671 		conv = do_proc_douintvec_conv;
672 
673 	if (write)
674 		return do_proc_douintvec_w(i, table, buffer, lenp, ppos,
675 					   conv, data);
676 	return do_proc_douintvec_r(i, buffer, lenp, ppos, conv, data);
677 }
678 
679 int do_proc_douintvec(struct ctl_table *table, int write,
680 		      void *buffer, size_t *lenp, loff_t *ppos,
681 		      int (*conv)(unsigned long *lvalp,
682 				  unsigned int *valp,
683 				  int write, void *data),
684 		      void *data)
685 {
686 	return __do_proc_douintvec(table->data, table, write,
687 				   buffer, lenp, ppos, conv, data);
688 }
689 
690 /**
691  * proc_dobool - read/write a bool
692  * @table: the sysctl table
693  * @write: %TRUE if this is a write to the sysctl file
694  * @buffer: the user buffer
695  * @lenp: the size of the user buffer
696  * @ppos: file position
697  *
698  * Reads/writes one integer value from/to the user buffer,
699  * treated as an ASCII string.
700  *
701  * table->data must point to a bool variable and table->maxlen must
702  * be sizeof(bool).
703  *
704  * Returns 0 on success.
705  */
706 int proc_dobool(struct ctl_table *table, int write, void *buffer,
707 		size_t *lenp, loff_t *ppos)
708 {
709 	struct ctl_table tmp;
710 	bool *data = table->data;
711 	int res, val;
712 
713 	/* Do not support arrays yet. */
714 	if (table->maxlen != sizeof(bool))
715 		return -EINVAL;
716 
717 	tmp = *table;
718 	tmp.maxlen = sizeof(val);
719 	tmp.data = &val;
720 
721 	val = READ_ONCE(*data);
722 	res = proc_dointvec(&tmp, write, buffer, lenp, ppos);
723 	if (res)
724 		return res;
725 	if (write)
726 		WRITE_ONCE(*data, val);
727 	return 0;
728 }
729 
730 /**
731  * proc_dointvec - read a vector of integers
732  * @table: the sysctl table
733  * @write: %TRUE if this is a write to the sysctl file
734  * @buffer: the user buffer
735  * @lenp: the size of the user buffer
736  * @ppos: file position
737  *
738  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
739  * values from/to the user buffer, treated as an ASCII string.
740  *
741  * Returns 0 on success.
742  */
743 int proc_dointvec(struct ctl_table *table, int write, void *buffer,
744 		  size_t *lenp, loff_t *ppos)
745 {
746 	return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL);
747 }
748 
749 #ifdef CONFIG_COMPACTION
750 static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table,
751 		int write, void *buffer, size_t *lenp, loff_t *ppos)
752 {
753 	int ret, old;
754 
755 	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || !write)
756 		return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
757 
758 	old = *(int *)table->data;
759 	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
760 	if (ret)
761 		return ret;
762 	if (old != *(int *)table->data)
763 		pr_warn_once("sysctl attribute %s changed by %s[%d]\n",
764 			     table->procname, current->comm,
765 			     task_pid_nr(current));
766 	return ret;
767 }
768 #endif
769 
770 /**
771  * proc_douintvec - read a vector of unsigned integers
772  * @table: the sysctl table
773  * @write: %TRUE if this is a write to the sysctl file
774  * @buffer: the user buffer
775  * @lenp: the size of the user buffer
776  * @ppos: file position
777  *
778  * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
779  * values from/to the user buffer, treated as an ASCII string.
780  *
781  * Returns 0 on success.
782  */
783 int proc_douintvec(struct ctl_table *table, int write, void *buffer,
784 		size_t *lenp, loff_t *ppos)
785 {
786 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
787 				 do_proc_douintvec_conv, NULL);
788 }
789 
790 /*
791  * Taint values can only be increased
792  * This means we can safely use a temporary.
793  */
794 static int proc_taint(struct ctl_table *table, int write,
795 			       void *buffer, size_t *lenp, loff_t *ppos)
796 {
797 	struct ctl_table t;
798 	unsigned long tmptaint = get_taint();
799 	int err;
800 
801 	if (write && !capable(CAP_SYS_ADMIN))
802 		return -EPERM;
803 
804 	t = *table;
805 	t.data = &tmptaint;
806 	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
807 	if (err < 0)
808 		return err;
809 
810 	if (write) {
811 		int i;
812 
813 		/*
814 		 * If we are relying on panic_on_taint not producing
815 		 * false positives due to userspace input, bail out
816 		 * before setting the requested taint flags.
817 		 */
818 		if (panic_on_taint_nousertaint && (tmptaint & panic_on_taint))
819 			return -EINVAL;
820 
821 		/*
822 		 * Poor man's atomic or. Not worth adding a primitive
823 		 * to everyone's atomic.h for this
824 		 */
825 		for (i = 0; i < TAINT_FLAGS_COUNT; i++)
826 			if ((1UL << i) & tmptaint)
827 				add_taint(i, LOCKDEP_STILL_OK);
828 	}
829 
830 	return err;
831 }
832 
833 /**
834  * struct do_proc_dointvec_minmax_conv_param - proc_dointvec_minmax() range checking structure
835  * @min: pointer to minimum allowable value
836  * @max: pointer to maximum allowable value
837  *
838  * The do_proc_dointvec_minmax_conv_param structure provides the
839  * minimum and maximum values for doing range checking for those sysctl
840  * parameters that use the proc_dointvec_minmax() handler.
841  */
842 struct do_proc_dointvec_minmax_conv_param {
843 	int *min;
844 	int *max;
845 };
846 
847 static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
848 					int *valp,
849 					int write, void *data)
850 {
851 	int tmp, ret;
852 	struct do_proc_dointvec_minmax_conv_param *param = data;
853 	/*
854 	 * If writing, first do so via a temporary local int so we can
855 	 * bounds-check it before touching *valp.
856 	 */
857 	int *ip = write ? &tmp : valp;
858 
859 	ret = do_proc_dointvec_conv(negp, lvalp, ip, write, data);
860 	if (ret)
861 		return ret;
862 
863 	if (write) {
864 		if ((param->min && *param->min > tmp) ||
865 		    (param->max && *param->max < tmp))
866 			return -EINVAL;
867 		WRITE_ONCE(*valp, tmp);
868 	}
869 
870 	return 0;
871 }
872 
873 /**
874  * proc_dointvec_minmax - read a vector of integers with min/max values
875  * @table: the sysctl table
876  * @write: %TRUE if this is a write to the sysctl file
877  * @buffer: the user buffer
878  * @lenp: the size of the user buffer
879  * @ppos: file position
880  *
881  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
882  * values from/to the user buffer, treated as an ASCII string.
883  *
884  * This routine will ensure the values are within the range specified by
885  * table->extra1 (min) and table->extra2 (max).
886  *
887  * Returns 0 on success or -EINVAL on write when the range check fails.
888  */
889 int proc_dointvec_minmax(struct ctl_table *table, int write,
890 		  void *buffer, size_t *lenp, loff_t *ppos)
891 {
892 	struct do_proc_dointvec_minmax_conv_param param = {
893 		.min = (int *) table->extra1,
894 		.max = (int *) table->extra2,
895 	};
896 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
897 				do_proc_dointvec_minmax_conv, &param);
898 }
899 
900 /**
901  * struct do_proc_douintvec_minmax_conv_param - proc_douintvec_minmax() range checking structure
902  * @min: pointer to minimum allowable value
903  * @max: pointer to maximum allowable value
904  *
905  * The do_proc_douintvec_minmax_conv_param structure provides the
906  * minimum and maximum values for doing range checking for those sysctl
907  * parameters that use the proc_douintvec_minmax() handler.
908  */
909 struct do_proc_douintvec_minmax_conv_param {
910 	unsigned int *min;
911 	unsigned int *max;
912 };
913 
914 static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
915 					 unsigned int *valp,
916 					 int write, void *data)
917 {
918 	int ret;
919 	unsigned int tmp;
920 	struct do_proc_douintvec_minmax_conv_param *param = data;
921 	/* write via temporary local uint for bounds-checking */
922 	unsigned int *up = write ? &tmp : valp;
923 
924 	ret = do_proc_douintvec_conv(lvalp, up, write, data);
925 	if (ret)
926 		return ret;
927 
928 	if (write) {
929 		if ((param->min && *param->min > tmp) ||
930 		    (param->max && *param->max < tmp))
931 			return -ERANGE;
932 
933 		WRITE_ONCE(*valp, tmp);
934 	}
935 
936 	return 0;
937 }
938 
939 /**
940  * proc_douintvec_minmax - read a vector of unsigned ints with min/max values
941  * @table: the sysctl table
942  * @write: %TRUE if this is a write to the sysctl file
943  * @buffer: the user buffer
944  * @lenp: the size of the user buffer
945  * @ppos: file position
946  *
947  * Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
948  * values from/to the user buffer, treated as an ASCII string. Negative
949  * strings are not allowed.
950  *
951  * This routine will ensure the values are within the range specified by
952  * table->extra1 (min) and table->extra2 (max). There is a final sanity
953  * check for UINT_MAX to avoid having to support wrap around uses from
954  * userspace.
955  *
956  * Returns 0 on success or -ERANGE on write when the range check fails.
957  */
958 int proc_douintvec_minmax(struct ctl_table *table, int write,
959 			  void *buffer, size_t *lenp, loff_t *ppos)
960 {
961 	struct do_proc_douintvec_minmax_conv_param param = {
962 		.min = (unsigned int *) table->extra1,
963 		.max = (unsigned int *) table->extra2,
964 	};
965 	return do_proc_douintvec(table, write, buffer, lenp, ppos,
966 				 do_proc_douintvec_minmax_conv, &param);
967 }
968 
969 /**
970  * proc_dou8vec_minmax - read a vector of unsigned chars with min/max values
971  * @table: the sysctl table
972  * @write: %TRUE if this is a write to the sysctl file
973  * @buffer: the user buffer
974  * @lenp: the size of the user buffer
975  * @ppos: file position
976  *
977  * Reads/writes up to table->maxlen/sizeof(u8) unsigned chars
978  * values from/to the user buffer, treated as an ASCII string. Negative
979  * strings are not allowed.
980  *
981  * This routine will ensure the values are within the range specified by
982  * table->extra1 (min) and table->extra2 (max).
983  *
984  * Returns 0 on success or an error on write when the range check fails.
985  */
986 int proc_dou8vec_minmax(struct ctl_table *table, int write,
987 			void *buffer, size_t *lenp, loff_t *ppos)
988 {
989 	struct ctl_table tmp;
990 	unsigned int min = 0, max = 255U, val;
991 	u8 *data = table->data;
992 	struct do_proc_douintvec_minmax_conv_param param = {
993 		.min = &min,
994 		.max = &max,
995 	};
996 	int res;
997 
998 	/* Do not support arrays yet. */
999 	if (table->maxlen != sizeof(u8))
1000 		return -EINVAL;
1001 
1002 	if (table->extra1) {
1003 		min = *(unsigned int *) table->extra1;
1004 		if (min > 255U)
1005 			return -EINVAL;
1006 	}
1007 	if (table->extra2) {
1008 		max = *(unsigned int *) table->extra2;
1009 		if (max > 255U)
1010 			return -EINVAL;
1011 	}
1012 
1013 	tmp = *table;
1014 
1015 	tmp.maxlen = sizeof(val);
1016 	tmp.data = &val;
1017 	val = READ_ONCE(*data);
1018 	res = do_proc_douintvec(&tmp, write, buffer, lenp, ppos,
1019 				do_proc_douintvec_minmax_conv, &param);
1020 	if (res)
1021 		return res;
1022 	if (write)
1023 		WRITE_ONCE(*data, val);
1024 	return 0;
1025 }
1026 EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
1027 
1028 #ifdef CONFIG_MAGIC_SYSRQ
1029 static int sysrq_sysctl_handler(struct ctl_table *table, int write,
1030 				void *buffer, size_t *lenp, loff_t *ppos)
1031 {
1032 	int tmp, ret;
1033 
1034 	tmp = sysrq_mask();
1035 
1036 	ret = __do_proc_dointvec(&tmp, table, write, buffer,
1037 			       lenp, ppos, NULL, NULL);
1038 	if (ret || !write)
1039 		return ret;
1040 
1041 	if (write)
1042 		sysrq_toggle_support(tmp);
1043 
1044 	return 0;
1045 }
1046 #endif
1047 
1048 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table,
1049 		int write, void *buffer, size_t *lenp, loff_t *ppos,
1050 		unsigned long convmul, unsigned long convdiv)
1051 {
1052 	unsigned long *i, *min, *max;
1053 	int vleft, first = 1, err = 0;
1054 	size_t left;
1055 	char *p;
1056 
1057 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
1058 		*lenp = 0;
1059 		return 0;
1060 	}
1061 
1062 	i = data;
1063 	min = table->extra1;
1064 	max = table->extra2;
1065 	vleft = table->maxlen / sizeof(unsigned long);
1066 	left = *lenp;
1067 
1068 	if (write) {
1069 		if (proc_first_pos_non_zero_ignore(ppos, table))
1070 			goto out;
1071 
1072 		if (left > PAGE_SIZE - 1)
1073 			left = PAGE_SIZE - 1;
1074 		p = buffer;
1075 	}
1076 
1077 	for (; left && vleft--; i++, first = 0) {
1078 		unsigned long val;
1079 
1080 		if (write) {
1081 			bool neg;
1082 
1083 			proc_skip_spaces(&p, &left);
1084 			if (!left)
1085 				break;
1086 
1087 			err = proc_get_long(&p, &left, &val, &neg,
1088 					     proc_wspace_sep,
1089 					     sizeof(proc_wspace_sep), NULL);
1090 			if (err || neg) {
1091 				err = -EINVAL;
1092 				break;
1093 			}
1094 
1095 			val = convmul * val / convdiv;
1096 			if ((min && val < *min) || (max && val > *max)) {
1097 				err = -EINVAL;
1098 				break;
1099 			}
1100 			WRITE_ONCE(*i, val);
1101 		} else {
1102 			val = convdiv * READ_ONCE(*i) / convmul;
1103 			if (!first)
1104 				proc_put_char(&buffer, &left, '\t');
1105 			proc_put_long(&buffer, &left, val, false);
1106 		}
1107 	}
1108 
1109 	if (!write && !first && left && !err)
1110 		proc_put_char(&buffer, &left, '\n');
1111 	if (write && !err)
1112 		proc_skip_spaces(&p, &left);
1113 	if (write && first)
1114 		return err ? : -EINVAL;
1115 	*lenp -= left;
1116 out:
1117 	*ppos += *lenp;
1118 	return err;
1119 }
1120 
1121 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
1122 		void *buffer, size_t *lenp, loff_t *ppos, unsigned long convmul,
1123 		unsigned long convdiv)
1124 {
1125 	return __do_proc_doulongvec_minmax(table->data, table, write,
1126 			buffer, lenp, ppos, convmul, convdiv);
1127 }
1128 
1129 /**
1130  * proc_doulongvec_minmax - read a vector of long integers 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.
1139  *
1140  * This routine will ensure the values are within the range specified by
1141  * table->extra1 (min) and table->extra2 (max).
1142  *
1143  * Returns 0 on success.
1144  */
1145 int proc_doulongvec_minmax(struct ctl_table *table, int write,
1146 			   void *buffer, size_t *lenp, loff_t *ppos)
1147 {
1148     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
1149 }
1150 
1151 /**
1152  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
1153  * @table: the sysctl table
1154  * @write: %TRUE if this is a write to the sysctl file
1155  * @buffer: the user buffer
1156  * @lenp: the size of the user buffer
1157  * @ppos: file position
1158  *
1159  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
1160  * values from/to the user buffer, treated as an ASCII string. The values
1161  * are treated as milliseconds, and converted to jiffies when they are stored.
1162  *
1163  * This routine will ensure the values are within the range specified by
1164  * table->extra1 (min) and table->extra2 (max).
1165  *
1166  * Returns 0 on success.
1167  */
1168 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1169 				      void *buffer, size_t *lenp, loff_t *ppos)
1170 {
1171     return do_proc_doulongvec_minmax(table, write, buffer,
1172 				     lenp, ppos, HZ, 1000l);
1173 }
1174 
1175 
1176 static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
1177 					 int *valp,
1178 					 int write, void *data)
1179 {
1180 	if (write) {
1181 		if (*lvalp > INT_MAX / HZ)
1182 			return 1;
1183 		if (*negp)
1184 			WRITE_ONCE(*valp, -*lvalp * HZ);
1185 		else
1186 			WRITE_ONCE(*valp, *lvalp * HZ);
1187 	} else {
1188 		int val = READ_ONCE(*valp);
1189 		unsigned long lval;
1190 		if (val < 0) {
1191 			*negp = true;
1192 			lval = -(unsigned long)val;
1193 		} else {
1194 			*negp = false;
1195 			lval = (unsigned long)val;
1196 		}
1197 		*lvalp = lval / HZ;
1198 	}
1199 	return 0;
1200 }
1201 
1202 static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
1203 						int *valp,
1204 						int write, void *data)
1205 {
1206 	if (write) {
1207 		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
1208 			return 1;
1209 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
1210 	} else {
1211 		int val = *valp;
1212 		unsigned long lval;
1213 		if (val < 0) {
1214 			*negp = true;
1215 			lval = -(unsigned long)val;
1216 		} else {
1217 			*negp = false;
1218 			lval = (unsigned long)val;
1219 		}
1220 		*lvalp = jiffies_to_clock_t(lval);
1221 	}
1222 	return 0;
1223 }
1224 
1225 static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
1226 					    int *valp,
1227 					    int write, void *data)
1228 {
1229 	if (write) {
1230 		unsigned long jif = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
1231 
1232 		if (jif > INT_MAX)
1233 			return 1;
1234 		WRITE_ONCE(*valp, (int)jif);
1235 	} else {
1236 		int val = READ_ONCE(*valp);
1237 		unsigned long lval;
1238 		if (val < 0) {
1239 			*negp = true;
1240 			lval = -(unsigned long)val;
1241 		} else {
1242 			*negp = false;
1243 			lval = (unsigned long)val;
1244 		}
1245 		*lvalp = jiffies_to_msecs(lval);
1246 	}
1247 	return 0;
1248 }
1249 
1250 static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lvalp,
1251 						int *valp, int write, void *data)
1252 {
1253 	int tmp, ret;
1254 	struct do_proc_dointvec_minmax_conv_param *param = data;
1255 	/*
1256 	 * If writing, first do so via a temporary local int so we can
1257 	 * bounds-check it before touching *valp.
1258 	 */
1259 	int *ip = write ? &tmp : valp;
1260 
1261 	ret = do_proc_dointvec_ms_jiffies_conv(negp, lvalp, ip, write, data);
1262 	if (ret)
1263 		return ret;
1264 
1265 	if (write) {
1266 		if ((param->min && *param->min > tmp) ||
1267 				(param->max && *param->max < tmp))
1268 			return -EINVAL;
1269 		*valp = tmp;
1270 	}
1271 	return 0;
1272 }
1273 
1274 /**
1275  * proc_dointvec_jiffies - read a vector of integers as seconds
1276  * @table: the sysctl table
1277  * @write: %TRUE if this is a write to the sysctl file
1278  * @buffer: the user buffer
1279  * @lenp: the size of the user buffer
1280  * @ppos: file position
1281  *
1282  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1283  * values from/to the user buffer, treated as an ASCII string.
1284  * The values read are assumed to be in seconds, and are converted into
1285  * jiffies.
1286  *
1287  * Returns 0 on success.
1288  */
1289 int proc_dointvec_jiffies(struct ctl_table *table, int write,
1290 			  void *buffer, size_t *lenp, loff_t *ppos)
1291 {
1292     return do_proc_dointvec(table,write,buffer,lenp,ppos,
1293 		    	    do_proc_dointvec_jiffies_conv,NULL);
1294 }
1295 
1296 int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1297 			  void *buffer, size_t *lenp, loff_t *ppos)
1298 {
1299 	struct do_proc_dointvec_minmax_conv_param param = {
1300 		.min = (int *) table->extra1,
1301 		.max = (int *) table->extra2,
1302 	};
1303 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
1304 			do_proc_dointvec_ms_jiffies_minmax_conv, &param);
1305 }
1306 
1307 /**
1308  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
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: pointer to the file position
1314  *
1315  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1316  * values from/to the user buffer, treated as an ASCII string.
1317  * The values read are assumed to be in 1/USER_HZ seconds, and
1318  * are converted into jiffies.
1319  *
1320  * Returns 0 on success.
1321  */
1322 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
1323 				 void *buffer, size_t *lenp, loff_t *ppos)
1324 {
1325 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
1326 				do_proc_dointvec_userhz_jiffies_conv, NULL);
1327 }
1328 
1329 /**
1330  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
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  * @ppos: the current position in the file
1337  *
1338  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1339  * values from/to the user buffer, treated as an ASCII string.
1340  * The values read are assumed to be in 1/1000 seconds, and
1341  * are converted into jiffies.
1342  *
1343  * Returns 0 on success.
1344  */
1345 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write, void *buffer,
1346 		size_t *lenp, loff_t *ppos)
1347 {
1348 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
1349 				do_proc_dointvec_ms_jiffies_conv, NULL);
1350 }
1351 
1352 static int proc_do_cad_pid(struct ctl_table *table, int write, void *buffer,
1353 		size_t *lenp, loff_t *ppos)
1354 {
1355 	struct pid *new_pid;
1356 	pid_t tmp;
1357 	int r;
1358 
1359 	tmp = pid_vnr(cad_pid);
1360 
1361 	r = __do_proc_dointvec(&tmp, table, write, buffer,
1362 			       lenp, ppos, NULL, NULL);
1363 	if (r || !write)
1364 		return r;
1365 
1366 	new_pid = find_get_pid(tmp);
1367 	if (!new_pid)
1368 		return -ESRCH;
1369 
1370 	put_pid(xchg(&cad_pid, new_pid));
1371 	return 0;
1372 }
1373 
1374 /**
1375  * proc_do_large_bitmap - read/write from/to a large bitmap
1376  * @table: the sysctl table
1377  * @write: %TRUE if this is a write to the sysctl file
1378  * @buffer: the user buffer
1379  * @lenp: the size of the user buffer
1380  * @ppos: file position
1381  *
1382  * The bitmap is stored at table->data and the bitmap length (in bits)
1383  * in table->maxlen.
1384  *
1385  * We use a range comma separated format (e.g. 1,3-4,10-10) so that
1386  * large bitmaps may be represented in a compact manner. Writing into
1387  * the file will clear the bitmap then update it with the given input.
1388  *
1389  * Returns 0 on success.
1390  */
1391 int proc_do_large_bitmap(struct ctl_table *table, int write,
1392 			 void *buffer, size_t *lenp, loff_t *ppos)
1393 {
1394 	int err = 0;
1395 	size_t left = *lenp;
1396 	unsigned long bitmap_len = table->maxlen;
1397 	unsigned long *bitmap = *(unsigned long **) table->data;
1398 	unsigned long *tmp_bitmap = NULL;
1399 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
1400 
1401 	if (!bitmap || !bitmap_len || !left || (*ppos && !write)) {
1402 		*lenp = 0;
1403 		return 0;
1404 	}
1405 
1406 	if (write) {
1407 		char *p = buffer;
1408 		size_t skipped = 0;
1409 
1410 		if (left > PAGE_SIZE - 1) {
1411 			left = PAGE_SIZE - 1;
1412 			/* How much of the buffer we'll skip this pass */
1413 			skipped = *lenp - left;
1414 		}
1415 
1416 		tmp_bitmap = bitmap_zalloc(bitmap_len, GFP_KERNEL);
1417 		if (!tmp_bitmap)
1418 			return -ENOMEM;
1419 		proc_skip_char(&p, &left, '\n');
1420 		while (!err && left) {
1421 			unsigned long val_a, val_b;
1422 			bool neg;
1423 			size_t saved_left;
1424 
1425 			/* In case we stop parsing mid-number, we can reset */
1426 			saved_left = left;
1427 			err = proc_get_long(&p, &left, &val_a, &neg, tr_a,
1428 					     sizeof(tr_a), &c);
1429 			/*
1430 			 * If we consumed the entirety of a truncated buffer or
1431 			 * only one char is left (may be a "-"), then stop here,
1432 			 * reset, & come back for more.
1433 			 */
1434 			if ((left <= 1) && skipped) {
1435 				left = saved_left;
1436 				break;
1437 			}
1438 
1439 			if (err)
1440 				break;
1441 			if (val_a >= bitmap_len || neg) {
1442 				err = -EINVAL;
1443 				break;
1444 			}
1445 
1446 			val_b = val_a;
1447 			if (left) {
1448 				p++;
1449 				left--;
1450 			}
1451 
1452 			if (c == '-') {
1453 				err = proc_get_long(&p, &left, &val_b,
1454 						     &neg, tr_b, sizeof(tr_b),
1455 						     &c);
1456 				/*
1457 				 * If we consumed all of a truncated buffer or
1458 				 * then stop here, reset, & come back for more.
1459 				 */
1460 				if (!left && skipped) {
1461 					left = saved_left;
1462 					break;
1463 				}
1464 
1465 				if (err)
1466 					break;
1467 				if (val_b >= bitmap_len || neg ||
1468 				    val_a > val_b) {
1469 					err = -EINVAL;
1470 					break;
1471 				}
1472 				if (left) {
1473 					p++;
1474 					left--;
1475 				}
1476 			}
1477 
1478 			bitmap_set(tmp_bitmap, val_a, val_b - val_a + 1);
1479 			proc_skip_char(&p, &left, '\n');
1480 		}
1481 		left += skipped;
1482 	} else {
1483 		unsigned long bit_a, bit_b = 0;
1484 		bool first = 1;
1485 
1486 		while (left) {
1487 			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
1488 			if (bit_a >= bitmap_len)
1489 				break;
1490 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
1491 						   bit_a + 1) - 1;
1492 
1493 			if (!first)
1494 				proc_put_char(&buffer, &left, ',');
1495 			proc_put_long(&buffer, &left, bit_a, false);
1496 			if (bit_a != bit_b) {
1497 				proc_put_char(&buffer, &left, '-');
1498 				proc_put_long(&buffer, &left, bit_b, false);
1499 			}
1500 
1501 			first = 0; bit_b++;
1502 		}
1503 		proc_put_char(&buffer, &left, '\n');
1504 	}
1505 
1506 	if (!err) {
1507 		if (write) {
1508 			if (*ppos)
1509 				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
1510 			else
1511 				bitmap_copy(bitmap, tmp_bitmap, bitmap_len);
1512 		}
1513 		*lenp -= left;
1514 		*ppos += *lenp;
1515 	}
1516 
1517 	bitmap_free(tmp_bitmap);
1518 	return err;
1519 }
1520 
1521 #else /* CONFIG_PROC_SYSCTL */
1522 
1523 int proc_dostring(struct ctl_table *table, int write,
1524 		  void *buffer, size_t *lenp, loff_t *ppos)
1525 {
1526 	return -ENOSYS;
1527 }
1528 
1529 int proc_dobool(struct ctl_table *table, int write,
1530 		void *buffer, size_t *lenp, loff_t *ppos)
1531 {
1532 	return -ENOSYS;
1533 }
1534 
1535 int proc_dointvec(struct ctl_table *table, int write,
1536 		  void *buffer, size_t *lenp, loff_t *ppos)
1537 {
1538 	return -ENOSYS;
1539 }
1540 
1541 int proc_douintvec(struct ctl_table *table, int write,
1542 		  void *buffer, size_t *lenp, loff_t *ppos)
1543 {
1544 	return -ENOSYS;
1545 }
1546 
1547 int proc_dointvec_minmax(struct ctl_table *table, int write,
1548 		    void *buffer, size_t *lenp, loff_t *ppos)
1549 {
1550 	return -ENOSYS;
1551 }
1552 
1553 int proc_douintvec_minmax(struct ctl_table *table, int write,
1554 			  void *buffer, size_t *lenp, loff_t *ppos)
1555 {
1556 	return -ENOSYS;
1557 }
1558 
1559 int proc_dou8vec_minmax(struct ctl_table *table, int write,
1560 			void *buffer, size_t *lenp, loff_t *ppos)
1561 {
1562 	return -ENOSYS;
1563 }
1564 
1565 int proc_dointvec_jiffies(struct ctl_table *table, int write,
1566 		    void *buffer, size_t *lenp, loff_t *ppos)
1567 {
1568 	return -ENOSYS;
1569 }
1570 
1571 int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1572 				    void *buffer, size_t *lenp, loff_t *ppos)
1573 {
1574 	return -ENOSYS;
1575 }
1576 
1577 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
1578 		    void *buffer, size_t *lenp, loff_t *ppos)
1579 {
1580 	return -ENOSYS;
1581 }
1582 
1583 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
1584 			     void *buffer, size_t *lenp, loff_t *ppos)
1585 {
1586 	return -ENOSYS;
1587 }
1588 
1589 int proc_doulongvec_minmax(struct ctl_table *table, int write,
1590 		    void *buffer, size_t *lenp, loff_t *ppos)
1591 {
1592 	return -ENOSYS;
1593 }
1594 
1595 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
1596 				      void *buffer, size_t *lenp, loff_t *ppos)
1597 {
1598 	return -ENOSYS;
1599 }
1600 
1601 int proc_do_large_bitmap(struct ctl_table *table, int write,
1602 			 void *buffer, size_t *lenp, loff_t *ppos)
1603 {
1604 	return -ENOSYS;
1605 }
1606 
1607 #endif /* CONFIG_PROC_SYSCTL */
1608 
1609 #if defined(CONFIG_SYSCTL)
1610 int proc_do_static_key(struct ctl_table *table, int write,
1611 		       void *buffer, size_t *lenp, loff_t *ppos)
1612 {
1613 	struct static_key *key = (struct static_key *)table->data;
1614 	static DEFINE_MUTEX(static_key_mutex);
1615 	int val, ret;
1616 	struct ctl_table tmp = {
1617 		.data   = &val,
1618 		.maxlen = sizeof(val),
1619 		.mode   = table->mode,
1620 		.extra1 = SYSCTL_ZERO,
1621 		.extra2 = SYSCTL_ONE,
1622 	};
1623 
1624 	if (write && !capable(CAP_SYS_ADMIN))
1625 		return -EPERM;
1626 
1627 	mutex_lock(&static_key_mutex);
1628 	val = static_key_enabled(key);
1629 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
1630 	if (write && !ret) {
1631 		if (val)
1632 			static_key_enable(key);
1633 		else
1634 			static_key_disable(key);
1635 	}
1636 	mutex_unlock(&static_key_mutex);
1637 	return ret;
1638 }
1639 
1640 static struct ctl_table kern_table[] = {
1641 	{
1642 		.procname	= "panic",
1643 		.data		= &panic_timeout,
1644 		.maxlen		= sizeof(int),
1645 		.mode		= 0644,
1646 		.proc_handler	= proc_dointvec,
1647 	},
1648 #ifdef CONFIG_PROC_SYSCTL
1649 	{
1650 		.procname	= "tainted",
1651 		.maxlen 	= sizeof(long),
1652 		.mode		= 0644,
1653 		.proc_handler	= proc_taint,
1654 	},
1655 	{
1656 		.procname	= "sysctl_writes_strict",
1657 		.data		= &sysctl_writes_strict,
1658 		.maxlen		= sizeof(int),
1659 		.mode		= 0644,
1660 		.proc_handler	= proc_dointvec_minmax,
1661 		.extra1		= SYSCTL_NEG_ONE,
1662 		.extra2		= SYSCTL_ONE,
1663 	},
1664 #endif
1665 	{
1666 		.procname	= "print-fatal-signals",
1667 		.data		= &print_fatal_signals,
1668 		.maxlen		= sizeof(int),
1669 		.mode		= 0644,
1670 		.proc_handler	= proc_dointvec,
1671 	},
1672 #ifdef CONFIG_SPARC
1673 	{
1674 		.procname	= "reboot-cmd",
1675 		.data		= reboot_command,
1676 		.maxlen		= 256,
1677 		.mode		= 0644,
1678 		.proc_handler	= proc_dostring,
1679 	},
1680 	{
1681 		.procname	= "stop-a",
1682 		.data		= &stop_a_enabled,
1683 		.maxlen		= sizeof (int),
1684 		.mode		= 0644,
1685 		.proc_handler	= proc_dointvec,
1686 	},
1687 	{
1688 		.procname	= "scons-poweroff",
1689 		.data		= &scons_pwroff,
1690 		.maxlen		= sizeof (int),
1691 		.mode		= 0644,
1692 		.proc_handler	= proc_dointvec,
1693 	},
1694 #endif
1695 #ifdef CONFIG_SPARC64
1696 	{
1697 		.procname	= "tsb-ratio",
1698 		.data		= &sysctl_tsb_ratio,
1699 		.maxlen		= sizeof (int),
1700 		.mode		= 0644,
1701 		.proc_handler	= proc_dointvec,
1702 	},
1703 #endif
1704 #ifdef CONFIG_PARISC
1705 	{
1706 		.procname	= "soft-power",
1707 		.data		= &pwrsw_enabled,
1708 		.maxlen		= sizeof (int),
1709 		.mode		= 0644,
1710 		.proc_handler	= proc_dointvec,
1711 	},
1712 #endif
1713 #ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
1714 	{
1715 		.procname	= "unaligned-trap",
1716 		.data		= &unaligned_enabled,
1717 		.maxlen		= sizeof (int),
1718 		.mode		= 0644,
1719 		.proc_handler	= proc_dointvec,
1720 	},
1721 #endif
1722 #ifdef CONFIG_STACK_TRACER
1723 	{
1724 		.procname	= "stack_tracer_enabled",
1725 		.data		= &stack_tracer_enabled,
1726 		.maxlen		= sizeof(int),
1727 		.mode		= 0644,
1728 		.proc_handler	= stack_trace_sysctl,
1729 	},
1730 #endif
1731 #ifdef CONFIG_TRACING
1732 	{
1733 		.procname	= "ftrace_dump_on_oops",
1734 		.data		= &ftrace_dump_on_oops,
1735 		.maxlen		= sizeof(int),
1736 		.mode		= 0644,
1737 		.proc_handler	= proc_dointvec,
1738 	},
1739 	{
1740 		.procname	= "traceoff_on_warning",
1741 		.data		= &__disable_trace_on_warning,
1742 		.maxlen		= sizeof(__disable_trace_on_warning),
1743 		.mode		= 0644,
1744 		.proc_handler	= proc_dointvec,
1745 	},
1746 	{
1747 		.procname	= "tracepoint_printk",
1748 		.data		= &tracepoint_printk,
1749 		.maxlen		= sizeof(tracepoint_printk),
1750 		.mode		= 0644,
1751 		.proc_handler	= tracepoint_printk_sysctl,
1752 	},
1753 #endif
1754 #ifdef CONFIG_MODULES
1755 	{
1756 		.procname	= "modprobe",
1757 		.data		= &modprobe_path,
1758 		.maxlen		= KMOD_PATH_LEN,
1759 		.mode		= 0644,
1760 		.proc_handler	= proc_dostring,
1761 	},
1762 	{
1763 		.procname	= "modules_disabled",
1764 		.data		= &modules_disabled,
1765 		.maxlen		= sizeof(int),
1766 		.mode		= 0644,
1767 		/* only handle a transition from default "0" to "1" */
1768 		.proc_handler	= proc_dointvec_minmax,
1769 		.extra1		= SYSCTL_ONE,
1770 		.extra2		= SYSCTL_ONE,
1771 	},
1772 #endif
1773 #ifdef CONFIG_UEVENT_HELPER
1774 	{
1775 		.procname	= "hotplug",
1776 		.data		= &uevent_helper,
1777 		.maxlen		= UEVENT_HELPER_PATH_LEN,
1778 		.mode		= 0644,
1779 		.proc_handler	= proc_dostring,
1780 	},
1781 #endif
1782 #ifdef CONFIG_MAGIC_SYSRQ
1783 	{
1784 		.procname	= "sysrq",
1785 		.data		= NULL,
1786 		.maxlen		= sizeof (int),
1787 		.mode		= 0644,
1788 		.proc_handler	= sysrq_sysctl_handler,
1789 	},
1790 #endif
1791 #ifdef CONFIG_PROC_SYSCTL
1792 	{
1793 		.procname	= "cad_pid",
1794 		.data		= NULL,
1795 		.maxlen		= sizeof (int),
1796 		.mode		= 0600,
1797 		.proc_handler	= proc_do_cad_pid,
1798 	},
1799 #endif
1800 	{
1801 		.procname	= "threads-max",
1802 		.data		= NULL,
1803 		.maxlen		= sizeof(int),
1804 		.mode		= 0644,
1805 		.proc_handler	= sysctl_max_threads,
1806 	},
1807 	{
1808 		.procname	= "usermodehelper",
1809 		.mode		= 0555,
1810 		.child		= usermodehelper_table,
1811 	},
1812 	{
1813 		.procname	= "overflowuid",
1814 		.data		= &overflowuid,
1815 		.maxlen		= sizeof(int),
1816 		.mode		= 0644,
1817 		.proc_handler	= proc_dointvec_minmax,
1818 		.extra1		= SYSCTL_ZERO,
1819 		.extra2		= SYSCTL_MAXOLDUID,
1820 	},
1821 	{
1822 		.procname	= "overflowgid",
1823 		.data		= &overflowgid,
1824 		.maxlen		= sizeof(int),
1825 		.mode		= 0644,
1826 		.proc_handler	= proc_dointvec_minmax,
1827 		.extra1		= SYSCTL_ZERO,
1828 		.extra2		= SYSCTL_MAXOLDUID,
1829 	},
1830 #ifdef CONFIG_S390
1831 	{
1832 		.procname	= "userprocess_debug",
1833 		.data		= &show_unhandled_signals,
1834 		.maxlen		= sizeof(int),
1835 		.mode		= 0644,
1836 		.proc_handler	= proc_dointvec,
1837 	},
1838 #endif
1839 	{
1840 		.procname	= "pid_max",
1841 		.data		= &pid_max,
1842 		.maxlen		= sizeof (int),
1843 		.mode		= 0644,
1844 		.proc_handler	= proc_dointvec_minmax,
1845 		.extra1		= &pid_max_min,
1846 		.extra2		= &pid_max_max,
1847 	},
1848 	{
1849 		.procname	= "panic_on_oops",
1850 		.data		= &panic_on_oops,
1851 		.maxlen		= sizeof(int),
1852 		.mode		= 0644,
1853 		.proc_handler	= proc_dointvec,
1854 	},
1855 	{
1856 		.procname	= "panic_print",
1857 		.data		= &panic_print,
1858 		.maxlen		= sizeof(unsigned long),
1859 		.mode		= 0644,
1860 		.proc_handler	= proc_doulongvec_minmax,
1861 	},
1862 	{
1863 		.procname	= "ngroups_max",
1864 		.data		= (void *)&ngroups_max,
1865 		.maxlen		= sizeof (int),
1866 		.mode		= 0444,
1867 		.proc_handler	= proc_dointvec,
1868 	},
1869 	{
1870 		.procname	= "cap_last_cap",
1871 		.data		= (void *)&cap_last_cap,
1872 		.maxlen		= sizeof(int),
1873 		.mode		= 0444,
1874 		.proc_handler	= proc_dointvec,
1875 	},
1876 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
1877 	{
1878 		.procname       = "unknown_nmi_panic",
1879 		.data           = &unknown_nmi_panic,
1880 		.maxlen         = sizeof (int),
1881 		.mode           = 0644,
1882 		.proc_handler   = proc_dointvec,
1883 	},
1884 #endif
1885 
1886 #if (defined(CONFIG_X86_32) || defined(CONFIG_PARISC)) && \
1887 	defined(CONFIG_DEBUG_STACKOVERFLOW)
1888 	{
1889 		.procname	= "panic_on_stackoverflow",
1890 		.data		= &sysctl_panic_on_stackoverflow,
1891 		.maxlen		= sizeof(int),
1892 		.mode		= 0644,
1893 		.proc_handler	= proc_dointvec,
1894 	},
1895 #endif
1896 #if defined(CONFIG_X86)
1897 	{
1898 		.procname	= "panic_on_unrecovered_nmi",
1899 		.data		= &panic_on_unrecovered_nmi,
1900 		.maxlen		= sizeof(int),
1901 		.mode		= 0644,
1902 		.proc_handler	= proc_dointvec,
1903 	},
1904 	{
1905 		.procname	= "panic_on_io_nmi",
1906 		.data		= &panic_on_io_nmi,
1907 		.maxlen		= sizeof(int),
1908 		.mode		= 0644,
1909 		.proc_handler	= proc_dointvec,
1910 	},
1911 	{
1912 		.procname	= "bootloader_type",
1913 		.data		= &bootloader_type,
1914 		.maxlen		= sizeof (int),
1915 		.mode		= 0444,
1916 		.proc_handler	= proc_dointvec,
1917 	},
1918 	{
1919 		.procname	= "bootloader_version",
1920 		.data		= &bootloader_version,
1921 		.maxlen		= sizeof (int),
1922 		.mode		= 0444,
1923 		.proc_handler	= proc_dointvec,
1924 	},
1925 	{
1926 		.procname	= "io_delay_type",
1927 		.data		= &io_delay_type,
1928 		.maxlen		= sizeof(int),
1929 		.mode		= 0644,
1930 		.proc_handler	= proc_dointvec,
1931 	},
1932 #endif
1933 #if defined(CONFIG_MMU)
1934 	{
1935 		.procname	= "randomize_va_space",
1936 		.data		= &randomize_va_space,
1937 		.maxlen		= sizeof(int),
1938 		.mode		= 0644,
1939 		.proc_handler	= proc_dointvec,
1940 	},
1941 #endif
1942 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
1943 	{
1944 		.procname	= "spin_retry",
1945 		.data		= &spin_retry,
1946 		.maxlen		= sizeof (int),
1947 		.mode		= 0644,
1948 		.proc_handler	= proc_dointvec,
1949 	},
1950 #endif
1951 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
1952 	{
1953 		.procname	= "acpi_video_flags",
1954 		.data		= &acpi_realmode_flags,
1955 		.maxlen		= sizeof (unsigned long),
1956 		.mode		= 0644,
1957 		.proc_handler	= proc_doulongvec_minmax,
1958 	},
1959 #endif
1960 #ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
1961 	{
1962 		.procname	= "ignore-unaligned-usertrap",
1963 		.data		= &no_unaligned_warning,
1964 		.maxlen		= sizeof (int),
1965 		.mode		= 0644,
1966 		.proc_handler	= proc_dointvec,
1967 	},
1968 #endif
1969 #ifdef CONFIG_IA64
1970 	{
1971 		.procname	= "unaligned-dump-stack",
1972 		.data		= &unaligned_dump_stack,
1973 		.maxlen		= sizeof (int),
1974 		.mode		= 0644,
1975 		.proc_handler	= proc_dointvec,
1976 	},
1977 #endif
1978 #ifdef CONFIG_RT_MUTEXES
1979 	{
1980 		.procname	= "max_lock_depth",
1981 		.data		= &max_lock_depth,
1982 		.maxlen		= sizeof(int),
1983 		.mode		= 0644,
1984 		.proc_handler	= proc_dointvec,
1985 	},
1986 #endif
1987 #ifdef CONFIG_KEYS
1988 	{
1989 		.procname	= "keys",
1990 		.mode		= 0555,
1991 		.child		= key_sysctls,
1992 	},
1993 #endif
1994 #ifdef CONFIG_PERF_EVENTS
1995 	/*
1996 	 * User-space scripts rely on the existence of this file
1997 	 * as a feature check for perf_events being enabled.
1998 	 *
1999 	 * So it's an ABI, do not remove!
2000 	 */
2001 	{
2002 		.procname	= "perf_event_paranoid",
2003 		.data		= &sysctl_perf_event_paranoid,
2004 		.maxlen		= sizeof(sysctl_perf_event_paranoid),
2005 		.mode		= 0644,
2006 		.proc_handler	= proc_dointvec,
2007 	},
2008 	{
2009 		.procname	= "perf_event_mlock_kb",
2010 		.data		= &sysctl_perf_event_mlock,
2011 		.maxlen		= sizeof(sysctl_perf_event_mlock),
2012 		.mode		= 0644,
2013 		.proc_handler	= proc_dointvec,
2014 	},
2015 	{
2016 		.procname	= "perf_event_max_sample_rate",
2017 		.data		= &sysctl_perf_event_sample_rate,
2018 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
2019 		.mode		= 0644,
2020 		.proc_handler	= perf_proc_update_handler,
2021 		.extra1		= SYSCTL_ONE,
2022 	},
2023 	{
2024 		.procname	= "perf_cpu_time_max_percent",
2025 		.data		= &sysctl_perf_cpu_time_max_percent,
2026 		.maxlen		= sizeof(sysctl_perf_cpu_time_max_percent),
2027 		.mode		= 0644,
2028 		.proc_handler	= perf_cpu_time_max_percent_handler,
2029 		.extra1		= SYSCTL_ZERO,
2030 		.extra2		= SYSCTL_ONE_HUNDRED,
2031 	},
2032 	{
2033 		.procname	= "perf_event_max_stack",
2034 		.data		= &sysctl_perf_event_max_stack,
2035 		.maxlen		= sizeof(sysctl_perf_event_max_stack),
2036 		.mode		= 0644,
2037 		.proc_handler	= perf_event_max_stack_handler,
2038 		.extra1		= SYSCTL_ZERO,
2039 		.extra2		= (void *)&six_hundred_forty_kb,
2040 	},
2041 	{
2042 		.procname	= "perf_event_max_contexts_per_stack",
2043 		.data		= &sysctl_perf_event_max_contexts_per_stack,
2044 		.maxlen		= sizeof(sysctl_perf_event_max_contexts_per_stack),
2045 		.mode		= 0644,
2046 		.proc_handler	= perf_event_max_stack_handler,
2047 		.extra1		= SYSCTL_ZERO,
2048 		.extra2		= SYSCTL_ONE_THOUSAND,
2049 	},
2050 #endif
2051 	{
2052 		.procname	= "panic_on_warn",
2053 		.data		= &panic_on_warn,
2054 		.maxlen		= sizeof(int),
2055 		.mode		= 0644,
2056 		.proc_handler	= proc_dointvec_minmax,
2057 		.extra1		= SYSCTL_ZERO,
2058 		.extra2		= SYSCTL_ONE,
2059 	},
2060 #ifdef CONFIG_TREE_RCU
2061 	{
2062 		.procname	= "panic_on_rcu_stall",
2063 		.data		= &sysctl_panic_on_rcu_stall,
2064 		.maxlen		= sizeof(sysctl_panic_on_rcu_stall),
2065 		.mode		= 0644,
2066 		.proc_handler	= proc_dointvec_minmax,
2067 		.extra1		= SYSCTL_ZERO,
2068 		.extra2		= SYSCTL_ONE,
2069 	},
2070 	{
2071 		.procname	= "max_rcu_stall_to_panic",
2072 		.data		= &sysctl_max_rcu_stall_to_panic,
2073 		.maxlen		= sizeof(sysctl_max_rcu_stall_to_panic),
2074 		.mode		= 0644,
2075 		.proc_handler	= proc_dointvec_minmax,
2076 		.extra1		= SYSCTL_ONE,
2077 		.extra2		= SYSCTL_INT_MAX,
2078 	},
2079 #endif
2080 	{ }
2081 };
2082 
2083 static struct ctl_table vm_table[] = {
2084 	{
2085 		.procname	= "overcommit_memory",
2086 		.data		= &sysctl_overcommit_memory,
2087 		.maxlen		= sizeof(sysctl_overcommit_memory),
2088 		.mode		= 0644,
2089 		.proc_handler	= overcommit_policy_handler,
2090 		.extra1		= SYSCTL_ZERO,
2091 		.extra2		= SYSCTL_TWO,
2092 	},
2093 	{
2094 		.procname	= "overcommit_ratio",
2095 		.data		= &sysctl_overcommit_ratio,
2096 		.maxlen		= sizeof(sysctl_overcommit_ratio),
2097 		.mode		= 0644,
2098 		.proc_handler	= overcommit_ratio_handler,
2099 	},
2100 	{
2101 		.procname	= "overcommit_kbytes",
2102 		.data		= &sysctl_overcommit_kbytes,
2103 		.maxlen		= sizeof(sysctl_overcommit_kbytes),
2104 		.mode		= 0644,
2105 		.proc_handler	= overcommit_kbytes_handler,
2106 	},
2107 	{
2108 		.procname	= "page-cluster",
2109 		.data		= &page_cluster,
2110 		.maxlen		= sizeof(int),
2111 		.mode		= 0644,
2112 		.proc_handler	= proc_dointvec_minmax,
2113 		.extra1		= SYSCTL_ZERO,
2114 		.extra2		= (void *)&page_cluster_max,
2115 	},
2116 	{
2117 		.procname	= "dirtytime_expire_seconds",
2118 		.data		= &dirtytime_expire_interval,
2119 		.maxlen		= sizeof(dirtytime_expire_interval),
2120 		.mode		= 0644,
2121 		.proc_handler	= dirtytime_interval_handler,
2122 		.extra1		= SYSCTL_ZERO,
2123 	},
2124 	{
2125 		.procname	= "swappiness",
2126 		.data		= &vm_swappiness,
2127 		.maxlen		= sizeof(vm_swappiness),
2128 		.mode		= 0644,
2129 		.proc_handler	= proc_dointvec_minmax,
2130 		.extra1		= SYSCTL_ZERO,
2131 		.extra2		= SYSCTL_TWO_HUNDRED,
2132 	},
2133 #ifdef CONFIG_NUMA
2134 	{
2135 		.procname	= "numa_stat",
2136 		.data		= &sysctl_vm_numa_stat,
2137 		.maxlen		= sizeof(int),
2138 		.mode		= 0644,
2139 		.proc_handler	= sysctl_vm_numa_stat_handler,
2140 		.extra1		= SYSCTL_ZERO,
2141 		.extra2		= SYSCTL_ONE,
2142 	},
2143 #endif
2144 #ifdef CONFIG_HUGETLB_PAGE
2145 	{
2146 		.procname	= "nr_hugepages",
2147 		.data		= NULL,
2148 		.maxlen		= sizeof(unsigned long),
2149 		.mode		= 0644,
2150 		.proc_handler	= hugetlb_sysctl_handler,
2151 	},
2152 #ifdef CONFIG_NUMA
2153 	{
2154 		.procname       = "nr_hugepages_mempolicy",
2155 		.data           = NULL,
2156 		.maxlen         = sizeof(unsigned long),
2157 		.mode           = 0644,
2158 		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
2159 	},
2160 #endif
2161 	 {
2162 		.procname	= "hugetlb_shm_group",
2163 		.data		= &sysctl_hugetlb_shm_group,
2164 		.maxlen		= sizeof(gid_t),
2165 		.mode		= 0644,
2166 		.proc_handler	= proc_dointvec,
2167 	 },
2168 	{
2169 		.procname	= "nr_overcommit_hugepages",
2170 		.data		= NULL,
2171 		.maxlen		= sizeof(unsigned long),
2172 		.mode		= 0644,
2173 		.proc_handler	= hugetlb_overcommit_handler,
2174 	},
2175 #endif
2176 	{
2177 		.procname	= "lowmem_reserve_ratio",
2178 		.data		= &sysctl_lowmem_reserve_ratio,
2179 		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
2180 		.mode		= 0644,
2181 		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
2182 	},
2183 	{
2184 		.procname	= "drop_caches",
2185 		.data		= &sysctl_drop_caches,
2186 		.maxlen		= sizeof(int),
2187 		.mode		= 0200,
2188 		.proc_handler	= drop_caches_sysctl_handler,
2189 		.extra1		= SYSCTL_ONE,
2190 		.extra2		= SYSCTL_FOUR,
2191 	},
2192 #ifdef CONFIG_COMPACTION
2193 	{
2194 		.procname	= "compact_memory",
2195 		.data		= NULL,
2196 		.maxlen		= sizeof(int),
2197 		.mode		= 0200,
2198 		.proc_handler	= sysctl_compaction_handler,
2199 	},
2200 	{
2201 		.procname	= "compaction_proactiveness",
2202 		.data		= &sysctl_compaction_proactiveness,
2203 		.maxlen		= sizeof(sysctl_compaction_proactiveness),
2204 		.mode		= 0644,
2205 		.proc_handler	= compaction_proactiveness_sysctl_handler,
2206 		.extra1		= SYSCTL_ZERO,
2207 		.extra2		= SYSCTL_ONE_HUNDRED,
2208 	},
2209 	{
2210 		.procname	= "extfrag_threshold",
2211 		.data		= &sysctl_extfrag_threshold,
2212 		.maxlen		= sizeof(int),
2213 		.mode		= 0644,
2214 		.proc_handler	= proc_dointvec_minmax,
2215 		.extra1		= SYSCTL_ZERO,
2216 		.extra2		= SYSCTL_ONE_THOUSAND,
2217 	},
2218 	{
2219 		.procname	= "compact_unevictable_allowed",
2220 		.data		= &sysctl_compact_unevictable_allowed,
2221 		.maxlen		= sizeof(int),
2222 		.mode		= 0644,
2223 		.proc_handler	= proc_dointvec_minmax_warn_RT_change,
2224 		.extra1		= SYSCTL_ZERO,
2225 		.extra2		= SYSCTL_ONE,
2226 	},
2227 
2228 #endif /* CONFIG_COMPACTION */
2229 	{
2230 		.procname	= "min_free_kbytes",
2231 		.data		= &min_free_kbytes,
2232 		.maxlen		= sizeof(min_free_kbytes),
2233 		.mode		= 0644,
2234 		.proc_handler	= min_free_kbytes_sysctl_handler,
2235 		.extra1		= SYSCTL_ZERO,
2236 	},
2237 	{
2238 		.procname	= "watermark_boost_factor",
2239 		.data		= &watermark_boost_factor,
2240 		.maxlen		= sizeof(watermark_boost_factor),
2241 		.mode		= 0644,
2242 		.proc_handler	= proc_dointvec_minmax,
2243 		.extra1		= SYSCTL_ZERO,
2244 	},
2245 	{
2246 		.procname	= "watermark_scale_factor",
2247 		.data		= &watermark_scale_factor,
2248 		.maxlen		= sizeof(watermark_scale_factor),
2249 		.mode		= 0644,
2250 		.proc_handler	= watermark_scale_factor_sysctl_handler,
2251 		.extra1		= SYSCTL_ONE,
2252 		.extra2		= SYSCTL_THREE_THOUSAND,
2253 	},
2254 	{
2255 		.procname	= "percpu_pagelist_high_fraction",
2256 		.data		= &percpu_pagelist_high_fraction,
2257 		.maxlen		= sizeof(percpu_pagelist_high_fraction),
2258 		.mode		= 0644,
2259 		.proc_handler	= percpu_pagelist_high_fraction_sysctl_handler,
2260 		.extra1		= SYSCTL_ZERO,
2261 	},
2262 	{
2263 		.procname	= "page_lock_unfairness",
2264 		.data		= &sysctl_page_lock_unfairness,
2265 		.maxlen		= sizeof(sysctl_page_lock_unfairness),
2266 		.mode		= 0644,
2267 		.proc_handler	= proc_dointvec_minmax,
2268 		.extra1		= SYSCTL_ZERO,
2269 	},
2270 #ifdef CONFIG_MMU
2271 	{
2272 		.procname	= "max_map_count",
2273 		.data		= &sysctl_max_map_count,
2274 		.maxlen		= sizeof(sysctl_max_map_count),
2275 		.mode		= 0644,
2276 		.proc_handler	= proc_dointvec_minmax,
2277 		.extra1		= SYSCTL_ZERO,
2278 	},
2279 #else
2280 	{
2281 		.procname	= "nr_trim_pages",
2282 		.data		= &sysctl_nr_trim_pages,
2283 		.maxlen		= sizeof(sysctl_nr_trim_pages),
2284 		.mode		= 0644,
2285 		.proc_handler	= proc_dointvec_minmax,
2286 		.extra1		= SYSCTL_ZERO,
2287 	},
2288 #endif
2289 	{
2290 		.procname	= "vfs_cache_pressure",
2291 		.data		= &sysctl_vfs_cache_pressure,
2292 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
2293 		.mode		= 0644,
2294 		.proc_handler	= proc_dointvec_minmax,
2295 		.extra1		= SYSCTL_ZERO,
2296 	},
2297 #if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
2298     defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
2299 	{
2300 		.procname	= "legacy_va_layout",
2301 		.data		= &sysctl_legacy_va_layout,
2302 		.maxlen		= sizeof(sysctl_legacy_va_layout),
2303 		.mode		= 0644,
2304 		.proc_handler	= proc_dointvec_minmax,
2305 		.extra1		= SYSCTL_ZERO,
2306 	},
2307 #endif
2308 #ifdef CONFIG_NUMA
2309 	{
2310 		.procname	= "zone_reclaim_mode",
2311 		.data		= &node_reclaim_mode,
2312 		.maxlen		= sizeof(node_reclaim_mode),
2313 		.mode		= 0644,
2314 		.proc_handler	= proc_dointvec_minmax,
2315 		.extra1		= SYSCTL_ZERO,
2316 	},
2317 	{
2318 		.procname	= "min_unmapped_ratio",
2319 		.data		= &sysctl_min_unmapped_ratio,
2320 		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
2321 		.mode		= 0644,
2322 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
2323 		.extra1		= SYSCTL_ZERO,
2324 		.extra2		= SYSCTL_ONE_HUNDRED,
2325 	},
2326 	{
2327 		.procname	= "min_slab_ratio",
2328 		.data		= &sysctl_min_slab_ratio,
2329 		.maxlen		= sizeof(sysctl_min_slab_ratio),
2330 		.mode		= 0644,
2331 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
2332 		.extra1		= SYSCTL_ZERO,
2333 		.extra2		= SYSCTL_ONE_HUNDRED,
2334 	},
2335 #endif
2336 #ifdef CONFIG_SMP
2337 	{
2338 		.procname	= "stat_interval",
2339 		.data		= &sysctl_stat_interval,
2340 		.maxlen		= sizeof(sysctl_stat_interval),
2341 		.mode		= 0644,
2342 		.proc_handler	= proc_dointvec_jiffies,
2343 	},
2344 	{
2345 		.procname	= "stat_refresh",
2346 		.data		= NULL,
2347 		.maxlen		= 0,
2348 		.mode		= 0600,
2349 		.proc_handler	= vmstat_refresh,
2350 	},
2351 #endif
2352 #ifdef CONFIG_MMU
2353 	{
2354 		.procname	= "mmap_min_addr",
2355 		.data		= &dac_mmap_min_addr,
2356 		.maxlen		= sizeof(unsigned long),
2357 		.mode		= 0644,
2358 		.proc_handler	= mmap_min_addr_handler,
2359 	},
2360 #endif
2361 #ifdef CONFIG_NUMA
2362 	{
2363 		.procname	= "numa_zonelist_order",
2364 		.data		= &numa_zonelist_order,
2365 		.maxlen		= NUMA_ZONELIST_ORDER_LEN,
2366 		.mode		= 0644,
2367 		.proc_handler	= numa_zonelist_order_handler,
2368 	},
2369 #endif
2370 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
2371    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
2372 	{
2373 		.procname	= "vdso_enabled",
2374 #ifdef CONFIG_X86_32
2375 		.data		= &vdso32_enabled,
2376 		.maxlen		= sizeof(vdso32_enabled),
2377 #else
2378 		.data		= &vdso_enabled,
2379 		.maxlen		= sizeof(vdso_enabled),
2380 #endif
2381 		.mode		= 0644,
2382 		.proc_handler	= proc_dointvec,
2383 		.extra1		= SYSCTL_ZERO,
2384 	},
2385 #endif
2386 #ifdef CONFIG_MEMORY_FAILURE
2387 	{
2388 		.procname	= "memory_failure_early_kill",
2389 		.data		= &sysctl_memory_failure_early_kill,
2390 		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
2391 		.mode		= 0644,
2392 		.proc_handler	= proc_dointvec_minmax,
2393 		.extra1		= SYSCTL_ZERO,
2394 		.extra2		= SYSCTL_ONE,
2395 	},
2396 	{
2397 		.procname	= "memory_failure_recovery",
2398 		.data		= &sysctl_memory_failure_recovery,
2399 		.maxlen		= sizeof(sysctl_memory_failure_recovery),
2400 		.mode		= 0644,
2401 		.proc_handler	= proc_dointvec_minmax,
2402 		.extra1		= SYSCTL_ZERO,
2403 		.extra2		= SYSCTL_ONE,
2404 	},
2405 #endif
2406 	{
2407 		.procname	= "user_reserve_kbytes",
2408 		.data		= &sysctl_user_reserve_kbytes,
2409 		.maxlen		= sizeof(sysctl_user_reserve_kbytes),
2410 		.mode		= 0644,
2411 		.proc_handler	= proc_doulongvec_minmax,
2412 	},
2413 	{
2414 		.procname	= "admin_reserve_kbytes",
2415 		.data		= &sysctl_admin_reserve_kbytes,
2416 		.maxlen		= sizeof(sysctl_admin_reserve_kbytes),
2417 		.mode		= 0644,
2418 		.proc_handler	= proc_doulongvec_minmax,
2419 	},
2420 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
2421 	{
2422 		.procname	= "mmap_rnd_bits",
2423 		.data		= &mmap_rnd_bits,
2424 		.maxlen		= sizeof(mmap_rnd_bits),
2425 		.mode		= 0600,
2426 		.proc_handler	= proc_dointvec_minmax,
2427 		.extra1		= (void *)&mmap_rnd_bits_min,
2428 		.extra2		= (void *)&mmap_rnd_bits_max,
2429 	},
2430 #endif
2431 #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
2432 	{
2433 		.procname	= "mmap_rnd_compat_bits",
2434 		.data		= &mmap_rnd_compat_bits,
2435 		.maxlen		= sizeof(mmap_rnd_compat_bits),
2436 		.mode		= 0600,
2437 		.proc_handler	= proc_dointvec_minmax,
2438 		.extra1		= (void *)&mmap_rnd_compat_bits_min,
2439 		.extra2		= (void *)&mmap_rnd_compat_bits_max,
2440 	},
2441 #endif
2442 #ifdef CONFIG_USERFAULTFD
2443 	{
2444 		.procname	= "unprivileged_userfaultfd",
2445 		.data		= &sysctl_unprivileged_userfaultfd,
2446 		.maxlen		= sizeof(sysctl_unprivileged_userfaultfd),
2447 		.mode		= 0644,
2448 		.proc_handler	= proc_dointvec_minmax,
2449 		.extra1		= SYSCTL_ZERO,
2450 		.extra2		= SYSCTL_ONE,
2451 	},
2452 #endif
2453 	{ }
2454 };
2455 
2456 static struct ctl_table debug_table[] = {
2457 #ifdef CONFIG_SYSCTL_EXCEPTION_TRACE
2458 	{
2459 		.procname	= "exception-trace",
2460 		.data		= &show_unhandled_signals,
2461 		.maxlen		= sizeof(int),
2462 		.mode		= 0644,
2463 		.proc_handler	= proc_dointvec
2464 	},
2465 #endif
2466 	{ }
2467 };
2468 
2469 static struct ctl_table dev_table[] = {
2470 	{ }
2471 };
2472 
2473 DECLARE_SYSCTL_BASE(kernel, kern_table);
2474 DECLARE_SYSCTL_BASE(vm, vm_table);
2475 DECLARE_SYSCTL_BASE(debug, debug_table);
2476 DECLARE_SYSCTL_BASE(dev, dev_table);
2477 
2478 int __init sysctl_init_bases(void)
2479 {
2480 	register_sysctl_base(kernel);
2481 	register_sysctl_base(vm);
2482 	register_sysctl_base(debug);
2483 	register_sysctl_base(dev);
2484 
2485 	return 0;
2486 }
2487 #endif /* CONFIG_SYSCTL */
2488 /*
2489  * No sense putting this after each symbol definition, twice,
2490  * exception granted :-)
2491  */
2492 EXPORT_SYMBOL(proc_dobool);
2493 EXPORT_SYMBOL(proc_dointvec);
2494 EXPORT_SYMBOL(proc_douintvec);
2495 EXPORT_SYMBOL(proc_dointvec_jiffies);
2496 EXPORT_SYMBOL(proc_dointvec_minmax);
2497 EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
2498 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2499 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2500 EXPORT_SYMBOL(proc_dostring);
2501 EXPORT_SYMBOL(proc_doulongvec_minmax);
2502 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2503 EXPORT_SYMBOL(proc_do_large_bitmap);
2504