projects/linux·blob v6.19-rc2 · refs

510 lines · 14.9 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2
3#include <linux/bitmap.h>
4#include <linux/ctype.h>
5#include <linux/errno.h>
6#include <linux/err.h>
7#include <linux/export.h>
8#include <linux/hex.h>
9#include <linux/kernel.h>
10#include <linux/mm.h>
11#include <linux/string.h>
12
13#include "kstrtox.h"
14
15/**
16 * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
17 *
18 * @ubuf: pointer to user buffer containing string.
19 * @ulen: buffer size in bytes. If string is smaller than this
20 * then it must be terminated with a \0.
21 * @maskp: pointer to bitmap array that will contain result.
22 * @nmaskbits: size of bitmap, in bits.
23 */
24int bitmap_parse_user(const char __user *ubuf,
25 unsigned int ulen, unsigned long *maskp,
26 int nmaskbits)
27{
28 char *buf;
29 int ret;
30
31 buf = memdup_user_nul(ubuf, ulen);
32 if (IS_ERR(buf))
33 return PTR_ERR(buf);
34
35 ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits);
36
37 kfree(buf);
38 return ret;
39}
40EXPORT_SYMBOL(bitmap_parse_user);
41
42/**
43 * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
44 * @list: indicates whether the bitmap must be list
45 * @buf: page aligned buffer into which string is placed
46 * @maskp: pointer to bitmap to convert
47 * @nmaskbits: size of bitmap, in bits
48 *
49 * Output format is a comma-separated list of decimal numbers and
50 * ranges if list is specified or hex digits grouped into comma-separated
51 * sets of 8 digits/set. Returns the number of characters written to buf.
52 *
53 * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
54 * area and that sufficient storage remains at @buf to accommodate the
55 * bitmap_print_to_pagebuf() output. Returns the number of characters
56 * actually printed to @buf, excluding terminating '\0'.
57 */
58int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
59 int nmaskbits)
60{
61 ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
62
63 return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
64 scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
65}
66EXPORT_SYMBOL(bitmap_print_to_pagebuf);
67
68/**
69 * bitmap_print_to_buf - convert bitmap to list or hex format ASCII string
70 * @list: indicates whether the bitmap must be list
71 * true: print in decimal list format
72 * false: print in hexadecimal bitmask format
73 * @buf: buffer into which string is placed
74 * @maskp: pointer to bitmap to convert
75 * @nmaskbits: size of bitmap, in bits
76 * @off: in the string from which we are copying, We copy to @buf
77 * @count: the maximum number of bytes to print
78 */
79static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
80 int nmaskbits, loff_t off, size_t count)
81{
82 const char *fmt = list ? "%*pbl\n" : "%*pb\n";
83 ssize_t size;
84 void *data;
85
86 data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp);
87 if (!data)
88 return -ENOMEM;
89
90 size = memory_read_from_buffer(buf, count, &off, data, strlen(data) + 1);
91 kfree(data);
92
93 return size;
94}
95
96/**
97 * bitmap_print_bitmask_to_buf - convert bitmap to hex bitmask format ASCII string
98 * @buf: buffer into which string is placed
99 * @maskp: pointer to bitmap to convert
100 * @nmaskbits: size of bitmap, in bits
101 * @off: in the string from which we are copying, We copy to @buf
102 * @count: the maximum number of bytes to print
103 *
104 * The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper
105 * cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
106 * bitmask and decimal list to userspace by sysfs ABI.
107 * Drivers might be using a normal attribute for this kind of ABIs. A
108 * normal attribute typically has show entry as below::
109 *
110 * static ssize_t example_attribute_show(struct device *dev,
111 * struct device_attribute *attr, char *buf)
112 * {
113 * ...
114 * return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max);
115 * }
116 *
117 * show entry of attribute has no offset and count parameters and this
118 * means the file is limited to one page only.
119 * bitmap_print_to_pagebuf() API works terribly well for this kind of
120 * normal attribute with buf parameter and without offset, count::
121 *
122 * bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
123 * int nmaskbits)
124 * {
125 * }
126 *
127 * The problem is once we have a large bitmap, we have a chance to get a
128 * bitmask or list more than one page. Especially for list, it could be
129 * as complex as 0,3,5,7,9,... We have no simple way to know it exact size.
130 * It turns out bin_attribute is a way to break this limit. bin_attribute
131 * has show entry as below::
132 *
133 * static ssize_t
134 * example_bin_attribute_show(struct file *filp, struct kobject *kobj,
135 * struct bin_attribute *attr, char *buf,
136 * loff_t offset, size_t count)
137 * {
138 * ...
139 * }
140 *
141 * With the new offset and count parameters, this makes sysfs ABI be able
142 * to support file size more than one page. For example, offset could be
143 * >= 4096.
144 * bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their
145 * cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf()
146 * make those drivers be able to support large bitmask and list after they
147 * move to use bin_attribute. In result, we have to pass the corresponding
148 * parameters such as off, count from bin_attribute show entry to this API.
149 *
150 * The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf()
151 * is similar with cpumap_print_to_pagebuf(), the difference is that
152 * bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption
153 * the destination buffer is exactly one page and won't be more than one page.
154 * cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other
155 * hand, mainly serves bin_attribute which doesn't work with exact one page,
156 * and it can break the size limit of converted decimal list and hexadecimal
157 * bitmask.
158 *
159 * WARNING!
160 *
161 * This function is not a replacement for sprintf() or bitmap_print_to_pagebuf().
162 * It is intended to workaround sysfs limitations discussed above and should be
163 * used carefully in general case for the following reasons:
164 *
165 * - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf().
166 * - Memory complexity is O(nbits), comparing to O(1) for snprintf().
167 * - @off and @count are NOT offset and number of bits to print.
168 * - If printing part of bitmap as list, the resulting string is not a correct
169 * list representation of bitmap. Particularly, some bits within or out of
170 * related interval may be erroneously set or unset. The format of the string
171 * may be broken, so bitmap_parselist-like parser may fail parsing it.
172 * - If printing the whole bitmap as list by parts, user must ensure the order
173 * of calls of the function such that the offset is incremented linearly.
174 * - If printing the whole bitmap as list by parts, user must keep bitmap
175 * unchanged between the very first and very last call. Otherwise concatenated
176 * result may be incorrect, and format may be broken.
177 *
178 * Returns the number of characters actually printed to @buf
179 */
180int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
181 int nmaskbits, loff_t off, size_t count)
182{
183 return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);
184}
185EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
186
187/**
188 * bitmap_print_list_to_buf - convert bitmap to decimal list format ASCII string
189 * @buf: buffer into which string is placed
190 * @maskp: pointer to bitmap to convert
191 * @nmaskbits: size of bitmap, in bits
192 * @off: in the string from which we are copying, We copy to @buf
193 * @count: the maximum number of bytes to print
194 *
195 * Everything is same with the above bitmap_print_bitmask_to_buf() except
196 * the print format.
197 */
198int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
199 int nmaskbits, loff_t off, size_t count)
200{
201 return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);
202}
203EXPORT_SYMBOL(bitmap_print_list_to_buf);
204
205/*
206 * Region 9-38:4/10 describes the following bitmap structure:
207 * 0 9 12 18 38 N
208 * .........****......****......****..................
209 * ^ ^ ^ ^ ^
210 * start off group_len end nbits
211 */
212struct region {
213 unsigned int start;
214 unsigned int off;
215 unsigned int group_len;
216 unsigned int end;
217 unsigned int nbits;
218};
219
220static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
221{
222 unsigned int start;
223
224 for (start = r->start; start <= r->end; start += r->group_len)
225 bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
226}
227
228static int bitmap_check_region(const struct region *r)
229{
230 if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
231 return -EINVAL;
232
233 if (r->end >= r->nbits)
234 return -ERANGE;
235
236 return 0;
237}
238
239static const char *bitmap_getnum(const char *str, unsigned int *num,
240 unsigned int lastbit)
241{
242 unsigned long long n;
243 unsigned int len;
244
245 if (str[0] == 'N') {
246 *num = lastbit;
247 return str + 1;
248 }
249
250 len = _parse_integer(str, 10, &n);
251 if (!len)
252 return ERR_PTR(-EINVAL);
253 if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
254 return ERR_PTR(-EOVERFLOW);
255
256 *num = n;
257 return str + len;
258}
259
260static inline bool end_of_str(char c)
261{
262 return c == '\0' || c == '\n';
263}
264
265static inline bool __end_of_region(char c)
266{
267 return isspace(c) || c == ',';
268}
269
270static inline bool end_of_region(char c)
271{
272 return __end_of_region(c) || end_of_str(c);
273}
274
275/*
276 * The format allows commas and whitespaces at the beginning
277 * of the region.
278 */
279static const char *bitmap_find_region(const char *str)
280{
281 while (__end_of_region(*str))
282 str++;
283
284 return end_of_str(*str) ? NULL : str;
285}
286
287static const char *bitmap_find_region_reverse(const char *start, const char *end)
288{
289 while (start <= end && __end_of_region(*end))
290 end--;
291
292 return end;
293}
294
295static const char *bitmap_parse_region(const char *str, struct region *r)
296{
297 unsigned int lastbit = r->nbits - 1;
298
299 if (!strncasecmp(str, "all", 3)) {
300 r->start = 0;
301 r->end = lastbit;
302 str += 3;
303
304 goto check_pattern;
305 }
306
307 str = bitmap_getnum(str, &r->start, lastbit);
308 if (IS_ERR(str))
309 return str;
310
311 if (end_of_region(*str))
312 goto no_end;
313
314 if (*str != '-')
315 return ERR_PTR(-EINVAL);
316
317 str = bitmap_getnum(str + 1, &r->end, lastbit);
318 if (IS_ERR(str))
319 return str;
320
321check_pattern:
322 if (end_of_region(*str))
323 goto no_pattern;
324
325 if (*str != ':')
326 return ERR_PTR(-EINVAL);
327
328 str = bitmap_getnum(str + 1, &r->off, lastbit);
329 if (IS_ERR(str))
330 return str;
331
332 if (*str != '/')
333 return ERR_PTR(-EINVAL);
334
335 return bitmap_getnum(str + 1, &r->group_len, lastbit);
336
337no_end:
338 r->end = r->start;
339no_pattern:
340 r->off = r->end + 1;
341 r->group_len = r->end + 1;
342
343 return end_of_str(*str) ? NULL : str;
344}
345
346/**
347 * bitmap_parselist - convert list format ASCII string to bitmap
348 * @buf: read user string from this buffer; must be terminated
349 * with a \0 or \n.
350 * @maskp: write resulting mask here
351 * @nmaskbits: number of bits in mask to be written
352 *
353 * Input format is a comma-separated list of decimal numbers and
354 * ranges. Consecutively set bits are shown as two hyphen-separated
355 * decimal numbers, the smallest and largest bit numbers set in
356 * the range.
357 * Optionally each range can be postfixed to denote that only parts of it
358 * should be set. The range will divided to groups of specific size.
359 * From each group will be used only defined amount of bits.
360 * Syntax: range:used_size/group_size
361 * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
362 * The value 'N' can be used as a dynamically substituted token for the
363 * maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is
364 * dynamic, so if system changes cause the bitmap width to change, such
365 * as more cores in a CPU list, then any ranges using N will also change.
366 *
367 * Returns: 0 on success, -errno on invalid input strings. Error values:
368 *
369 * - ``-EINVAL``: wrong region format
370 * - ``-EINVAL``: invalid character in string
371 * - ``-ERANGE``: bit number specified too large for mask
372 * - ``-EOVERFLOW``: integer overflow in the input parameters
373 */
374int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
375{
376 struct region r;
377 long ret;
378
379 r.nbits = nmaskbits;
380 bitmap_zero(maskp, r.nbits);
381
382 while (buf) {
383 buf = bitmap_find_region(buf);
384 if (buf == NULL)
385 return 0;
386
387 buf = bitmap_parse_region(buf, &r);
388 if (IS_ERR(buf))
389 return PTR_ERR(buf);
390
391 ret = bitmap_check_region(&r);
392 if (ret)
393 return ret;
394
395 bitmap_set_region(&r, maskp);
396 }
397
398 return 0;
399}
400EXPORT_SYMBOL(bitmap_parselist);
401
402
403/**
404 * bitmap_parselist_user() - convert user buffer's list format ASCII
405 * string to bitmap
406 *
407 * @ubuf: pointer to user buffer containing string.
408 * @ulen: buffer size in bytes. If string is smaller than this
409 * then it must be terminated with a \0.
410 * @maskp: pointer to bitmap array that will contain result.
411 * @nmaskbits: size of bitmap, in bits.
412 *
413 * Wrapper for bitmap_parselist(), providing it with user buffer.
414 */
415int bitmap_parselist_user(const char __user *ubuf,
416 unsigned int ulen, unsigned long *maskp,
417 int nmaskbits)
418{
419 char *buf;
420 int ret;
421
422 buf = memdup_user_nul(ubuf, ulen);
423 if (IS_ERR(buf))
424 return PTR_ERR(buf);
425
426 ret = bitmap_parselist(buf, maskp, nmaskbits);
427
428 kfree(buf);
429 return ret;
430}
431EXPORT_SYMBOL(bitmap_parselist_user);
432
433static const char *bitmap_get_x32_reverse(const char *start,
434 const char *end, u32 *num)
435{
436 u32 ret = 0;
437 int c, i;
438
439 for (i = 0; i < 32; i += 4) {
440 c = hex_to_bin(*end--);
441 if (c < 0)
442 return ERR_PTR(-EINVAL);
443
444 ret |= c << i;
445
446 if (start > end || __end_of_region(*end))
447 goto out;
448 }
449
450 if (hex_to_bin(*end--) >= 0)
451 return ERR_PTR(-EOVERFLOW);
452out:
453 *num = ret;
454 return end;
455}
456
457/**
458 * bitmap_parse - convert an ASCII hex string into a bitmap.
459 * @start: pointer to buffer containing string.
460 * @buflen: buffer size in bytes. If string is smaller than this
461 * then it must be terminated with a \0 or \n. In that case,
462 * UINT_MAX may be provided instead of string length.
463 * @maskp: pointer to bitmap array that will contain result.
464 * @nmaskbits: size of bitmap, in bits.
465 *
466 * Commas group hex digits into chunks. Each chunk defines exactly 32
467 * bits of the resultant bitmask. No chunk may specify a value larger
468 * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
469 * then leading 0-bits are prepended. %-EINVAL is returned for illegal
470 * characters. Grouping such as "1,,5", ",44", "," or "" is allowed.
471 * Leading, embedded and trailing whitespace accepted.
472 */
473int bitmap_parse(const char *start, unsigned int buflen,
474 unsigned long *maskp, int nmaskbits)
475{
476 const char *end = strnchrnul(start, buflen, '\n') - 1;
477 int chunks = BITS_TO_U32(nmaskbits);
478 u32 *bitmap = (u32 *)maskp;
479 int unset_bit;
480 int chunk;
481
482 for (chunk = 0; ; chunk++) {
483 end = bitmap_find_region_reverse(start, end);
484 if (start > end)
485 break;
486
487 if (!chunks--)
488 return -EOVERFLOW;
489
490#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
491 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
492#else
493 end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
494#endif
495 if (IS_ERR(end))
496 return PTR_ERR(end);
497 }
498
499 unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
500 if (unset_bit < nmaskbits) {
501 bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);
502 return 0;
503 }
504
505 if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)
506 return -EOVERFLOW;
507
508 return 0;
509}
510EXPORT_SYMBOL(bitmap_parse);