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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/power/cpupower/utils/helpers/bitmask.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/power/cpupower/utils/helpers/bitmask.c')
-rw-r--r-- | tools/power/cpupower/utils/helpers/bitmask.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/tools/power/cpupower/utils/helpers/bitmask.c b/tools/power/cpupower/utils/helpers/bitmask.c new file mode 100644 index 000000000..649d87cb8 --- /dev/null +++ b/tools/power/cpupower/utils/helpers/bitmask.c @@ -0,0 +1,293 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include <helpers/bitmask.h> + +/* How many bits in an unsigned long */ +#define bitsperlong (8 * sizeof(unsigned long)) + +/* howmany(a,b) : how many elements of size b needed to hold all of a */ +#define howmany(x, y) (((x)+((y)-1))/(y)) + +/* How many longs in mask of n bits */ +#define longsperbits(n) howmany(n, bitsperlong) + +#define max(a, b) ((a) > (b) ? (a) : (b)) + +/* + * Allocate and free `struct bitmask *` + */ + +/* Allocate a new `struct bitmask` with a size of n bits */ +struct bitmask *bitmask_alloc(unsigned int n) +{ + struct bitmask *bmp; + + bmp = malloc(sizeof(*bmp)); + if (!bmp) + return 0; + bmp->size = n; + bmp->maskp = calloc(longsperbits(n), sizeof(unsigned long)); + if (!bmp->maskp) { + free(bmp); + return 0; + } + return bmp; +} + +/* Free `struct bitmask` */ +void bitmask_free(struct bitmask *bmp) +{ + if (!bmp) + return; + free(bmp->maskp); + bmp->maskp = (unsigned long *)0xdeadcdef; /* double free tripwire */ + free(bmp); +} + +/* + * The routines _getbit() and _setbit() are the only + * routines that actually understand the layout of bmp->maskp[]. + * + * On little endian architectures, this could simply be an array of + * bytes. But the kernel layout of bitmasks _is_ visible to userspace + * via the sched_(set/get)affinity calls in Linux 2.6, and on big + * endian architectures, it is painfully obvious that this is an + * array of unsigned longs. + */ + +/* Return the value (0 or 1) of bit n in bitmask bmp */ +static unsigned int _getbit(const struct bitmask *bmp, unsigned int n) +{ + if (n < bmp->size) + return (bmp->maskp[n/bitsperlong] >> (n % bitsperlong)) & 1; + else + return 0; +} + +/* Set bit n in bitmask bmp to value v (0 or 1) */ +static void _setbit(struct bitmask *bmp, unsigned int n, unsigned int v) +{ + if (n < bmp->size) { + if (v) + bmp->maskp[n/bitsperlong] |= 1UL << (n % bitsperlong); + else + bmp->maskp[n/bitsperlong] &= + ~(1UL << (n % bitsperlong)); + } +} + +/* + * When parsing bitmask lists, only allow numbers, separated by one + * of the allowed next characters. + * + * The parameter 'sret' is the return from a sscanf "%u%c". It is + * -1 if the sscanf input string was empty. It is 0 if the first + * character in the sscanf input string was not a decimal number. + * It is 1 if the unsigned number matching the "%u" was the end of the + * input string. It is 2 if one or more additional characters followed + * the matched unsigned number. If it is 2, then 'nextc' is the first + * character following the number. The parameter 'ok_next_chars' + * is the nul-terminated list of allowed next characters. + * + * The mask term just scanned was ok if and only if either the numbers + * matching the %u were all of the input or if the next character in + * the input past the numbers was one of the allowed next characters. + */ +static int scan_was_ok(int sret, char nextc, const char *ok_next_chars) +{ + return sret == 1 || + (sret == 2 && strchr(ok_next_chars, nextc) != NULL); +} + +static const char *nexttoken(const char *q, int sep) +{ + if (q) + q = strchr(q, sep); + if (q) + q++; + return q; +} + +/* Set a single bit i in bitmask */ +struct bitmask *bitmask_setbit(struct bitmask *bmp, unsigned int i) +{ + _setbit(bmp, i, 1); + return bmp; +} + +/* Set all bits in bitmask: bmp = ~0 */ +struct bitmask *bitmask_setall(struct bitmask *bmp) +{ + unsigned int i; + for (i = 0; i < bmp->size; i++) + _setbit(bmp, i, 1); + return bmp; +} + +/* Clear all bits in bitmask: bmp = 0 */ +struct bitmask *bitmask_clearall(struct bitmask *bmp) +{ + unsigned int i; + for (i = 0; i < bmp->size; i++) + _setbit(bmp, i, 0); + return bmp; +} + +/* True if all bits are clear */ +int bitmask_isallclear(const struct bitmask *bmp) +{ + unsigned int i; + for (i = 0; i < bmp->size; i++) + if (_getbit(bmp, i)) + return 0; + return 1; +} + +/* True if specified bit i is set */ +int bitmask_isbitset(const struct bitmask *bmp, unsigned int i) +{ + return _getbit(bmp, i); +} + +/* Number of lowest set bit (min) */ +unsigned int bitmask_first(const struct bitmask *bmp) +{ + return bitmask_next(bmp, 0); +} + +/* Number of highest set bit (max) */ +unsigned int bitmask_last(const struct bitmask *bmp) +{ + unsigned int i; + unsigned int m = bmp->size; + for (i = 0; i < bmp->size; i++) + if (_getbit(bmp, i)) + m = i; + return m; +} + +/* Number of next set bit at or above given bit i */ +unsigned int bitmask_next(const struct bitmask *bmp, unsigned int i) +{ + unsigned int n; + for (n = i; n < bmp->size; n++) + if (_getbit(bmp, n)) + break; + return n; +} + +/* + * Parses a comma-separated list of numbers and ranges of numbers, + * with optional ':%u' strides modifying ranges, into provided bitmask. + * Some examples of input lists and their equivalent simple list: + * Input Equivalent to + * 0-3 0,1,2,3 + * 0-7:2 0,2,4,6 + * 1,3,5-7 1,3,5,6,7 + * 0-3:2,8-15:4 0,2,8,12 + */ +int bitmask_parselist(const char *buf, struct bitmask *bmp) +{ + const char *p, *q; + + bitmask_clearall(bmp); + + q = buf; + while (p = q, q = nexttoken(q, ','), p) { + unsigned int a; /* begin of range */ + unsigned int b; /* end of range */ + unsigned int s; /* stride */ + const char *c1, *c2; /* next tokens after '-' or ',' */ + char nextc; /* char after sscanf %u match */ + int sret; /* sscanf return (number of matches) */ + + sret = sscanf(p, "%u%c", &a, &nextc); + if (!scan_was_ok(sret, nextc, ",-")) + goto err; + b = a; + s = 1; + c1 = nexttoken(p, '-'); + c2 = nexttoken(p, ','); + if (c1 != NULL && (c2 == NULL || c1 < c2)) { + sret = sscanf(c1, "%u%c", &b, &nextc); + if (!scan_was_ok(sret, nextc, ",:")) + goto err; + c1 = nexttoken(c1, ':'); + if (c1 != NULL && (c2 == NULL || c1 < c2)) { + sret = sscanf(c1, "%u%c", &s, &nextc); + if (!scan_was_ok(sret, nextc, ",")) + goto err; + } + } + if (!(a <= b)) + goto err; + if (b >= bmp->size) + goto err; + while (a <= b) { + _setbit(bmp, a, 1); + a += s; + } + } + return 0; +err: + bitmask_clearall(bmp); + return -1; +} + +/* + * emit(buf, buflen, rbot, rtop, len) + * + * Helper routine for bitmask_displaylist(). Write decimal number + * or range to buf+len, suppressing output past buf+buflen, with optional + * comma-prefix. Return len of what would be written to buf, if it + * all fit. + */ + +static inline int emit(char *buf, int buflen, int rbot, int rtop, int len) +{ + if (len > 0) + len += snprintf(buf + len, max(buflen - len, 0), ","); + if (rbot == rtop) + len += snprintf(buf + len, max(buflen - len, 0), "%d", rbot); + else + len += snprintf(buf + len, max(buflen - len, 0), "%d-%d", + rbot, rtop); + return len; +} + +/* + * Write decimal list representation of bmp to buf. + * + * Output 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. Output format is compatible with the format + * accepted as input by bitmap_parselist(). + * + * The return value is the number of characters which would be + * generated for the given input, excluding the trailing '\0', as + * per ISO C99. + */ + +int bitmask_displaylist(char *buf, int buflen, const struct bitmask *bmp) +{ + int len = 0; + /* current bit is 'cur', most recently seen range is [rbot, rtop] */ + unsigned int cur, rbot, rtop; + + if (buflen > 0) + *buf = 0; + rbot = cur = bitmask_first(bmp); + while (cur < bmp->size) { + rtop = cur; + cur = bitmask_next(bmp, cur+1); + if (cur >= bmp->size || cur > rtop + 1) { + len = emit(buf, buflen, rbot, rtop, len); + rbot = cur; + } + } + return len; +} |