// SPDX-License-Identifier: GPL-2.0-only #include <linux/bitmap.h> #include <linux/ctype.h> #include <linux/errno.h> #include <linux/err.h> #include <linux/export.h> #include <linux/hex.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/string.h> #include "kstrtox.h" /** * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap * * @ubuf: pointer to user buffer containing string. * @ulen: buffer size in bytes. If string is smaller than this * then it must be terminated with a \0. * @maskp: pointer to bitmap array that will contain result. * @nmaskbits: size of bitmap, in bits. */ int bitmap_parse_user(const char __user *ubuf, unsigned int ulen, unsigned long *maskp, int nmaskbits) { … } EXPORT_SYMBOL(…); /** * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string * @list: indicates whether the bitmap must be list * @buf: page aligned buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * * Output format is a comma-separated list of decimal numbers and * ranges if list is specified or hex digits grouped into comma-separated * sets of 8 digits/set. Returns the number of characters written to buf. * * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned * area and that sufficient storage remains at @buf to accommodate the * bitmap_print_to_pagebuf() output. Returns the number of characters * actually printed to @buf, excluding terminating '\0'. */ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, int nmaskbits) { … } EXPORT_SYMBOL(…); /** * bitmap_print_to_buf - convert bitmap to list or hex format ASCII string * @list: indicates whether the bitmap must be list * true: print in decimal list format * false: print in hexadecimal bitmask format * @buf: buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * @off: in the string from which we are copying, We copy to @buf * @count: the maximum number of bytes to print */ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, int nmaskbits, loff_t off, size_t count) { … } /** * bitmap_print_bitmask_to_buf - convert bitmap to hex bitmask format ASCII string * @buf: buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * @off: in the string from which we are copying, We copy to @buf * @count: the maximum number of bytes to print * * The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper * cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal * bitmask and decimal list to userspace by sysfs ABI. * Drivers might be using a normal attribute for this kind of ABIs. A * normal attribute typically has show entry as below:: * * static ssize_t example_attribute_show(struct device *dev, * struct device_attribute *attr, char *buf) * { * ... * return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max); * } * * show entry of attribute has no offset and count parameters and this * means the file is limited to one page only. * bitmap_print_to_pagebuf() API works terribly well for this kind of * normal attribute with buf parameter and without offset, count:: * * bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, * int nmaskbits) * { * } * * The problem is once we have a large bitmap, we have a chance to get a * bitmask or list more than one page. Especially for list, it could be * as complex as 0,3,5,7,9,... We have no simple way to know it exact size. * It turns out bin_attribute is a way to break this limit. bin_attribute * has show entry as below:: * * static ssize_t * example_bin_attribute_show(struct file *filp, struct kobject *kobj, * struct bin_attribute *attr, char *buf, * loff_t offset, size_t count) * { * ... * } * * With the new offset and count parameters, this makes sysfs ABI be able * to support file size more than one page. For example, offset could be * >= 4096. * bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their * cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf() * make those drivers be able to support large bitmask and list after they * move to use bin_attribute. In result, we have to pass the corresponding * parameters such as off, count from bin_attribute show entry to this API. * * The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf() * is similar with cpumap_print_to_pagebuf(), the difference is that * bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption * the destination buffer is exactly one page and won't be more than one page. * cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other * hand, mainly serves bin_attribute which doesn't work with exact one page, * and it can break the size limit of converted decimal list and hexadecimal * bitmask. * * WARNING! * * This function is not a replacement for sprintf() or bitmap_print_to_pagebuf(). * It is intended to workaround sysfs limitations discussed above and should be * used carefully in general case for the following reasons: * * - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf(). * - Memory complexity is O(nbits), comparing to O(1) for snprintf(). * - @off and @count are NOT offset and number of bits to print. * - If printing part of bitmap as list, the resulting string is not a correct * list representation of bitmap. Particularly, some bits within or out of * related interval may be erroneously set or unset. The format of the string * may be broken, so bitmap_parselist-like parser may fail parsing it. * - If printing the whole bitmap as list by parts, user must ensure the order * of calls of the function such that the offset is incremented linearly. * - If printing the whole bitmap as list by parts, user must keep bitmap * unchanged between the very first and very last call. Otherwise concatenated * result may be incorrect, and format may be broken. * * Returns the number of characters actually printed to @buf */ int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp, int nmaskbits, loff_t off, size_t count) { … } EXPORT_SYMBOL(…); /** * bitmap_print_list_to_buf - convert bitmap to decimal list format ASCII string * @buf: buffer into which string is placed * @maskp: pointer to bitmap to convert * @nmaskbits: size of bitmap, in bits * @off: in the string from which we are copying, We copy to @buf * @count: the maximum number of bytes to print * * Everything is same with the above bitmap_print_bitmask_to_buf() except * the print format. */ int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp, int nmaskbits, loff_t off, size_t count) { … } EXPORT_SYMBOL(…); /* * Region 9-38:4/10 describes the following bitmap structure: * 0 9 12 18 38 N * .........****......****......****.................. * ^ ^ ^ ^ ^ * start off group_len end nbits */ struct region { … }; static void bitmap_set_region(const struct region *r, unsigned long *bitmap) { … } static int bitmap_check_region(const struct region *r) { … } static const char *bitmap_getnum(const char *str, unsigned int *num, unsigned int lastbit) { … } static inline bool end_of_str(char c) { … } static inline bool __end_of_region(char c) { … } static inline bool end_of_region(char c) { … } /* * The format allows commas and whitespaces at the beginning * of the region. */ static const char *bitmap_find_region(const char *str) { … } static const char *bitmap_find_region_reverse(const char *start, const char *end) { … } static const char *bitmap_parse_region(const char *str, struct region *r) { … } /** * bitmap_parselist - convert list format ASCII string to bitmap * @buf: read user string from this buffer; must be terminated * with a \0 or \n. * @maskp: write resulting mask here * @nmaskbits: number of bits in mask to be written * * Input format is a comma-separated list of decimal numbers and * ranges. Consecutively set bits are shown as two hyphen-separated * decimal numbers, the smallest and largest bit numbers set in * the range. * Optionally each range can be postfixed to denote that only parts of it * should be set. The range will divided to groups of specific size. * From each group will be used only defined amount of bits. * Syntax: range:used_size/group_size * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769 * The value 'N' can be used as a dynamically substituted token for the * maximum allowed value; i.e (nmaskbits - 1). Keep in mind that it is * dynamic, so if system changes cause the bitmap width to change, such * as more cores in a CPU list, then any ranges using N will also change. * * Returns: 0 on success, -errno on invalid input strings. Error values: * * - ``-EINVAL``: wrong region format * - ``-EINVAL``: invalid character in string * - ``-ERANGE``: bit number specified too large for mask * - ``-EOVERFLOW``: integer overflow in the input parameters */ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits) { … } EXPORT_SYMBOL(…); /** * bitmap_parselist_user() - convert user buffer's list format ASCII * string to bitmap * * @ubuf: pointer to user buffer containing string. * @ulen: buffer size in bytes. If string is smaller than this * then it must be terminated with a \0. * @maskp: pointer to bitmap array that will contain result. * @nmaskbits: size of bitmap, in bits. * * Wrapper for bitmap_parselist(), providing it with user buffer. */ int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen, unsigned long *maskp, int nmaskbits) { … } EXPORT_SYMBOL(…); static const char *bitmap_get_x32_reverse(const char *start, const char *end, u32 *num) { … } /** * bitmap_parse - convert an ASCII hex string into a bitmap. * @start: pointer to buffer containing string. * @buflen: buffer size in bytes. If string is smaller than this * then it must be terminated with a \0 or \n. In that case, * UINT_MAX may be provided instead of string length. * @maskp: pointer to bitmap array that will contain result. * @nmaskbits: size of bitmap, in bits. * * Commas group hex digits into chunks. Each chunk defines exactly 32 * bits of the resultant bitmask. No chunk may specify a value larger * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value * then leading 0-bits are prepended. %-EINVAL is returned for illegal * characters. Grouping such as "1,,5", ",44", "," or "" is allowed. * Leading, embedded and trailing whitespace accepted. */ int bitmap_parse(const char *start, unsigned int buflen, unsigned long *maskp, int nmaskbits) { … } EXPORT_SYMBOL(…);
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