ia64/xen-unstable

view xen/common/bitmap.c @ 19835:edfdeb150f27

Fix buildsystem to detect udev > version 124

udev removed the udevinfo symlink from versions higher than 123 and
xen's build-system could not detect if udev is in place and has the
required version.

Signed-off-by: Marc-A. Dahlhaus <mad@wol.de>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 25 13:02:37 2009 +0100 (2009-06-25)
parents 7c455af5998a
children
line source
1 /*
2 * lib/bitmap.c
3 * Helper functions for bitmap.h.
4 *
5 * This source code is licensed under the GNU General Public License,
6 * Version 2. See the file COPYING for more details.
7 */
8 #include <xen/config.h>
9 #include <xen/types.h>
10 #include <xen/errno.h>
11 #include <xen/bitmap.h>
12 #include <xen/bitops.h>
13 #include <asm/byteorder.h>
15 /*
16 * bitmaps provide an array of bits, implemented using an an
17 * array of unsigned longs. The number of valid bits in a
18 * given bitmap does _not_ need to be an exact multiple of
19 * BITS_PER_LONG.
20 *
21 * The possible unused bits in the last, partially used word
22 * of a bitmap are 'don't care'. The implementation makes
23 * no particular effort to keep them zero. It ensures that
24 * their value will not affect the results of any operation.
25 * The bitmap operations that return Boolean (bitmap_empty,
26 * for example) or scalar (bitmap_weight, for example) results
27 * carefully filter out these unused bits from impacting their
28 * results.
29 *
30 * These operations actually hold to a slightly stronger rule:
31 * if you don't input any bitmaps to these ops that have some
32 * unused bits set, then they won't output any set unused bits
33 * in output bitmaps.
34 *
35 * The byte ordering of bitmaps is more natural on little
36 * endian architectures. See the big-endian headers
37 * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
38 * for the best explanations of this ordering.
39 */
41 int __bitmap_empty(const unsigned long *bitmap, int bits)
42 {
43 int k, lim = bits/BITS_PER_LONG;
44 for (k = 0; k < lim; ++k)
45 if (bitmap[k])
46 return 0;
48 if (bits % BITS_PER_LONG)
49 if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
50 return 0;
52 return 1;
53 }
54 EXPORT_SYMBOL(__bitmap_empty);
56 int __bitmap_full(const unsigned long *bitmap, int bits)
57 {
58 int k, lim = bits/BITS_PER_LONG;
59 for (k = 0; k < lim; ++k)
60 if (~bitmap[k])
61 return 0;
63 if (bits % BITS_PER_LONG)
64 if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
65 return 0;
67 return 1;
68 }
69 EXPORT_SYMBOL(__bitmap_full);
71 int __bitmap_equal(const unsigned long *bitmap1,
72 const unsigned long *bitmap2, int bits)
73 {
74 int k, lim = bits/BITS_PER_LONG;
75 for (k = 0; k < lim; ++k)
76 if (bitmap1[k] != bitmap2[k])
77 return 0;
79 if (bits % BITS_PER_LONG)
80 if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
81 return 0;
83 return 1;
84 }
85 EXPORT_SYMBOL(__bitmap_equal);
87 void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
88 {
89 int k, lim = bits/BITS_PER_LONG;
90 for (k = 0; k < lim; ++k)
91 dst[k] = ~src[k];
93 if (bits % BITS_PER_LONG)
94 dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
95 }
96 EXPORT_SYMBOL(__bitmap_complement);
98 /*
99 * __bitmap_shift_right - logical right shift of the bits in a bitmap
100 * @dst - destination bitmap
101 * @src - source bitmap
102 * @nbits - shift by this many bits
103 * @bits - bitmap size, in bits
104 *
105 * Shifting right (dividing) means moving bits in the MS -> LS bit
106 * direction. Zeros are fed into the vacated MS positions and the
107 * LS bits shifted off the bottom are lost.
108 */
109 void __bitmap_shift_right(unsigned long *dst,
110 const unsigned long *src, int shift, int bits)
111 {
112 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
113 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
114 unsigned long mask = (1UL << left) - 1;
115 for (k = 0; off + k < lim; ++k) {
116 unsigned long upper, lower;
118 /*
119 * If shift is not word aligned, take lower rem bits of
120 * word above and make them the top rem bits of result.
121 */
122 if (!rem || off + k + 1 >= lim)
123 upper = 0;
124 else {
125 upper = src[off + k + 1];
126 if (off + k + 1 == lim - 1 && left)
127 upper &= mask;
128 }
129 lower = src[off + k];
130 if (left && off + k == lim - 1)
131 lower &= mask;
132 dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem;
133 if (left && k == lim - 1)
134 dst[k] &= mask;
135 }
136 if (off)
137 memset(&dst[lim - off], 0, off*sizeof(unsigned long));
138 }
139 EXPORT_SYMBOL(__bitmap_shift_right);
142 /*
143 * __bitmap_shift_left - logical left shift of the bits in a bitmap
144 * @dst - destination bitmap
145 * @src - source bitmap
146 * @nbits - shift by this many bits
147 * @bits - bitmap size, in bits
148 *
149 * Shifting left (multiplying) means moving bits in the LS -> MS
150 * direction. Zeros are fed into the vacated LS bit positions
151 * and those MS bits shifted off the top are lost.
152 */
154 void __bitmap_shift_left(unsigned long *dst,
155 const unsigned long *src, int shift, int bits)
156 {
157 int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
158 int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
159 for (k = lim - off - 1; k >= 0; --k) {
160 unsigned long upper, lower;
162 /*
163 * If shift is not word aligned, take upper rem bits of
164 * word below and make them the bottom rem bits of result.
165 */
166 if (rem && k > 0)
167 lower = src[k - 1];
168 else
169 lower = 0;
170 upper = src[k];
171 if (left && k == lim - 1)
172 upper &= (1UL << left) - 1;
173 dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem;
174 if (left && k + off == lim - 1)
175 dst[k + off] &= (1UL << left) - 1;
176 }
177 if (off)
178 memset(dst, 0, off*sizeof(unsigned long));
179 }
180 EXPORT_SYMBOL(__bitmap_shift_left);
182 void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
183 const unsigned long *bitmap2, int bits)
184 {
185 int k;
186 int nr = BITS_TO_LONGS(bits);
188 for (k = 0; k < nr; k++)
189 dst[k] = bitmap1[k] & bitmap2[k];
190 }
191 EXPORT_SYMBOL(__bitmap_and);
193 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
194 const unsigned long *bitmap2, int bits)
195 {
196 int k;
197 int nr = BITS_TO_LONGS(bits);
199 for (k = 0; k < nr; k++)
200 dst[k] = bitmap1[k] | bitmap2[k];
201 }
202 EXPORT_SYMBOL(__bitmap_or);
204 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
205 const unsigned long *bitmap2, int bits)
206 {
207 int k;
208 int nr = BITS_TO_LONGS(bits);
210 for (k = 0; k < nr; k++)
211 dst[k] = bitmap1[k] ^ bitmap2[k];
212 }
213 EXPORT_SYMBOL(__bitmap_xor);
215 void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
216 const unsigned long *bitmap2, int bits)
217 {
218 int k;
219 int nr = BITS_TO_LONGS(bits);
221 for (k = 0; k < nr; k++)
222 dst[k] = bitmap1[k] & ~bitmap2[k];
223 }
224 EXPORT_SYMBOL(__bitmap_andnot);
226 int __bitmap_intersects(const unsigned long *bitmap1,
227 const unsigned long *bitmap2, int bits)
228 {
229 int k, lim = bits/BITS_PER_LONG;
230 for (k = 0; k < lim; ++k)
231 if (bitmap1[k] & bitmap2[k])
232 return 1;
234 if (bits % BITS_PER_LONG)
235 if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
236 return 1;
237 return 0;
238 }
239 EXPORT_SYMBOL(__bitmap_intersects);
241 int __bitmap_subset(const unsigned long *bitmap1,
242 const unsigned long *bitmap2, int bits)
243 {
244 int k, lim = bits/BITS_PER_LONG;
245 for (k = 0; k < lim; ++k)
246 if (bitmap1[k] & ~bitmap2[k])
247 return 0;
249 if (bits % BITS_PER_LONG)
250 if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
251 return 0;
252 return 1;
253 }
254 EXPORT_SYMBOL(__bitmap_subset);
256 #if BITS_PER_LONG == 32
257 int __bitmap_weight(const unsigned long *bitmap, int bits)
258 {
259 int k, w = 0, lim = bits/BITS_PER_LONG;
261 for (k = 0; k < lim; k++)
262 w += hweight32(bitmap[k]);
264 if (bits % BITS_PER_LONG)
265 w += hweight32(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
267 return w;
268 }
269 #else
270 int __bitmap_weight(const unsigned long *bitmap, int bits)
271 {
272 int k, w = 0, lim = bits/BITS_PER_LONG;
274 for (k = 0; k < lim; k++)
275 w += hweight64(bitmap[k]);
277 if (bits % BITS_PER_LONG)
278 w += hweight64(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));
280 return w;
281 }
282 #endif
283 EXPORT_SYMBOL(__bitmap_weight);
285 /*
286 * Bitmap printing & parsing functions: first version by Bill Irwin,
287 * second version by Paul Jackson, third by Joe Korty.
288 */
290 #define CHUNKSZ 32
291 #define nbits_to_hold_value(val) fls(val)
292 #define roundup_power2(val,modulus) (((val) + (modulus) - 1) & ~((modulus) - 1))
293 #define unhex(c) (isdigit(c) ? (c - '0') : (toupper(c) - 'A' + 10))
294 #define BASEDEC 10 /* fancier cpuset lists input in decimal */
296 /**
297 * bitmap_scnprintf - convert bitmap to an ASCII hex string.
298 * @buf: byte buffer into which string is placed
299 * @buflen: reserved size of @buf, in bytes
300 * @maskp: pointer to bitmap to convert
301 * @nmaskbits: size of bitmap, in bits
302 *
303 * Exactly @nmaskbits bits are displayed. Hex digits are grouped into
304 * comma-separated sets of eight digits per set.
305 */
306 int bitmap_scnprintf(char *buf, unsigned int buflen,
307 const unsigned long *maskp, int nmaskbits)
308 {
309 int i, word, bit, len = 0;
310 unsigned long val;
311 const char *sep = "";
312 int chunksz;
313 u32 chunkmask;
315 chunksz = nmaskbits & (CHUNKSZ - 1);
316 if (chunksz == 0)
317 chunksz = CHUNKSZ;
319 i = roundup_power2(nmaskbits, CHUNKSZ) - CHUNKSZ;
320 for (; i >= 0; i -= CHUNKSZ) {
321 chunkmask = ((1ULL << chunksz) - 1);
322 word = i / BITS_PER_LONG;
323 bit = i % BITS_PER_LONG;
324 val = (maskp[word] >> bit) & chunkmask;
325 len += scnprintf(buf+len, buflen-len, "%s%0*lx", sep,
326 (chunksz+3)/4, val);
327 chunksz = CHUNKSZ;
328 sep = ",";
329 }
330 return len;
331 }
332 EXPORT_SYMBOL(bitmap_scnprintf);
334 /*
335 * bscnl_emit(buf, buflen, rbot, rtop, bp)
336 *
337 * Helper routine for bitmap_scnlistprintf(). Write decimal number
338 * or range to buf, suppressing output past buf+buflen, with optional
339 * comma-prefix. Return len of what would be written to buf, if it
340 * all fit.
341 */
342 static inline int bscnl_emit(char *buf, int buflen, int rbot, int rtop, int len)
343 {
344 if (len > 0)
345 len += scnprintf(buf + len, buflen - len, ",");
346 if (rbot == rtop)
347 len += scnprintf(buf + len, buflen - len, "%d", rbot);
348 else
349 len += scnprintf(buf + len, buflen - len, "%d-%d", rbot, rtop);
350 return len;
351 }
353 /**
354 * bitmap_scnlistprintf - convert bitmap to list format ASCII string
355 * @buf: byte buffer into which string is placed
356 * @buflen: reserved size of @buf, in bytes
357 * @maskp: pointer to bitmap to convert
358 * @nmaskbits: size of bitmap, in bits
359 *
360 * Output format is a comma-separated list of decimal numbers and
361 * ranges. Consecutively set bits are shown as two hyphen-separated
362 * decimal numbers, the smallest and largest bit numbers set in
363 * the range. Output format is compatible with the format
364 * accepted as input by bitmap_parselist().
365 *
366 * The return value is the number of characters which would be
367 * generated for the given input, excluding the trailing '\0', as
368 * per ISO C99.
369 */
370 int bitmap_scnlistprintf(char *buf, unsigned int buflen,
371 const unsigned long *maskp, int nmaskbits)
372 {
373 int len = 0;
374 /* current bit is 'cur', most recently seen range is [rbot, rtop] */
375 int cur, rbot, rtop;
377 rbot = cur = find_first_bit(maskp, nmaskbits);
378 while (cur < nmaskbits) {
379 rtop = cur;
380 cur = find_next_bit(maskp, nmaskbits, cur+1);
381 if (cur >= nmaskbits || cur > rtop + 1) {
382 len = bscnl_emit(buf, buflen, rbot, rtop, len);
383 rbot = cur;
384 }
385 }
386 return len;
387 }
388 EXPORT_SYMBOL(bitmap_scnlistprintf);
390 /**
391 * bitmap_find_free_region - find a contiguous aligned mem region
392 * @bitmap: an array of unsigned longs corresponding to the bitmap
393 * @bits: number of bits in the bitmap
394 * @order: region size to find (size is actually 1<<order)
395 *
396 * This is used to allocate a memory region from a bitmap. The idea is
397 * that the region has to be 1<<order sized and 1<<order aligned (this
398 * makes the search algorithm much faster).
399 *
400 * The region is marked as set bits in the bitmap if a free one is
401 * found.
402 *
403 * Returns either beginning of region or negative error
404 */
405 int bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
406 {
407 unsigned long mask;
408 int pages = 1 << order;
409 int i;
411 if(pages > BITS_PER_LONG)
412 return -EINVAL;
414 /* make a mask of the order */
415 mask = (1ul << (pages - 1));
416 mask += mask - 1;
418 /* run up the bitmap pages bits at a time */
419 for (i = 0; i < bits; i += pages) {
420 int index = i/BITS_PER_LONG;
421 int offset = i - (index * BITS_PER_LONG);
422 if((bitmap[index] & (mask << offset)) == 0) {
423 /* set region in bimap */
424 bitmap[index] |= (mask << offset);
425 return i;
426 }
427 }
428 return -ENOMEM;
429 }
430 EXPORT_SYMBOL(bitmap_find_free_region);
432 /**
433 * bitmap_release_region - release allocated bitmap region
434 * @bitmap: a pointer to the bitmap
435 * @pos: the beginning of the region
436 * @order: the order of the bits to release (number is 1<<order)
437 *
438 * This is the complement to __bitmap_find_free_region and releases
439 * the found region (by clearing it in the bitmap).
440 */
441 void bitmap_release_region(unsigned long *bitmap, int pos, int order)
442 {
443 int pages = 1 << order;
444 unsigned long mask = (1ul << (pages - 1));
445 int index = pos/BITS_PER_LONG;
446 int offset = pos - (index * BITS_PER_LONG);
447 mask += mask - 1;
448 bitmap[index] &= ~(mask << offset);
449 }
450 EXPORT_SYMBOL(bitmap_release_region);
452 int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
453 {
454 int pages = 1 << order;
455 unsigned long mask = (1ul << (pages - 1));
456 int index = pos/BITS_PER_LONG;
457 int offset = pos - (index * BITS_PER_LONG);
459 /* We don't do regions of pages > BITS_PER_LONG. The
460 * algorithm would be a simple look for multiple zeros in the
461 * array, but there's no driver today that needs this. If you
462 * trip this BUG(), you get to code it... */
463 BUG_ON(pages > BITS_PER_LONG);
464 mask += mask - 1;
465 if (bitmap[index] & (mask << offset))
466 return -EBUSY;
467 bitmap[index] |= (mask << offset);
468 return 0;
469 }
470 EXPORT_SYMBOL(bitmap_allocate_region);
472 #ifdef __BIG_ENDIAN
474 void bitmap_long_to_byte(uint8_t *bp, const unsigned long *lp, int nbits)
475 {
476 unsigned long l;
477 int i, j, b;
479 for (i = 0, b = 0; nbits > 0; i++, b += sizeof(l)) {
480 l = lp[i];
481 for (j = 0; (j < sizeof(l)) && (nbits > 0); j++) {
482 bp[b+j] = l;
483 l >>= 8;
484 nbits -= 8;
485 }
486 }
487 }
489 void bitmap_byte_to_long(unsigned long *lp, const uint8_t *bp, int nbits)
490 {
491 unsigned long l;
492 int i, j, b;
494 for (i = 0, b = 0; nbits > 0; i++, b += sizeof(l)) {
495 l = 0;
496 for (j = 0; (j < sizeof(l)) && (nbits > 0); j++) {
497 l |= (unsigned long)bp[b+j] << (j*8);
498 nbits -= 8;
499 }
500 lp[i] = l;
501 }
502 }
504 #elif defined(__LITTLE_ENDIAN)
506 void bitmap_long_to_byte(uint8_t *bp, const unsigned long *lp, int nbits)
507 {
508 memcpy(bp, lp, (nbits+7)/8);
509 }
511 void bitmap_byte_to_long(unsigned long *lp, const uint8_t *bp, int nbits)
512 {
513 /* We may need to pad the final longword with zeroes. */
514 if (nbits & (BITS_PER_LONG-1))
515 lp[BITS_TO_LONGS(nbits)-1] = 0;
516 memcpy(lp, bp, (nbits+7)/8);
517 }
519 #endif