include/linux/cpumask.h

   1 #ifndef __LINUX_CPUMASK_H
   2 #define __LINUX_CPUMASK_H
   3
   4 /*
   5  * Cpumasks provide a bitmap suitable for representing the
   6  * set of CPU's in a system, one bit position per CPU number.  In general,
   7  * only nr_cpu_ids (<= NR_CPUS) bits are valid.
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/threads.h>
  11 #include <linux/bitmap.h>
  12 #include <linux/bug.h>
  13
  14 /* Don't assign or return these: may not be this big! */
  15 typedef struct cpumask { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t;
  16
  17 /**
  18  * cpumask_bits - get the bits in a cpumask
  19  * @maskp: the struct cpumask *
  20  *
  21  * You should only assume nr_cpu_ids bits of this mask are valid.  This is
  22  * a macro so it's const-correct.
  23  */
  24 #define cpumask_bits(maskp) ((maskp)->bits)
  25
  26 /**
  27  * cpumask_pr_args - printf args to output a cpumask
  28  * @maskp: cpumask to be printed
  29  *
  30  * Can be used to provide arguments for '%*pb[l]' when printing a cpumask.
  31  */
  32 #define cpumask_pr_args(maskp)          nr_cpu_ids, cpumask_bits(maskp)
  33
  34 #if NR_CPUS == 1
  35 #define nr_cpu_ids              1
  36 #else
  37 extern int nr_cpu_ids;
  38 #endif
  39
  40 #ifdef CONFIG_CPUMASK_OFFSTACK
  41 /* Assuming NR_CPUS is huge, a runtime limit is more efficient.  Also,
  42  * not all bits may be allocated. */
  43 #define nr_cpumask_bits nr_cpu_ids
  44 #else
  45 #define nr_cpumask_bits NR_CPUS
  46 #endif
  47
  48 /*
  49  * The following particular system cpumasks and operations manage
  50  * possible, present, active and online cpus.
  51  *
  52  *     cpu_possible_mask- has bit 'cpu' set iff cpu is populatable
  53  *     cpu_present_mask - has bit 'cpu' set iff cpu is populated
  54  *     cpu_online_mask  - has bit 'cpu' set iff cpu available to scheduler
  55  *     cpu_active_mask  - has bit 'cpu' set iff cpu available to migration
  56  *
  57  *  If !CONFIG_HOTPLUG_CPU, present == possible, and active == online.
  58  *
  59  *  The cpu_possible_mask is fixed at boot time, as the set of CPU id's
  60  *  that it is possible might ever be plugged in at anytime during the
  61  *  life of that system boot.  The cpu_present_mask is dynamic(*),
  62  *  representing which CPUs are currently plugged in.  And
  63  *  cpu_online_mask is the dynamic subset of cpu_present_mask,
  64  *  indicating those CPUs available for scheduling.
  65  *
  66  *  If HOTPLUG is enabled, then cpu_possible_mask is forced to have
  67  *  all NR_CPUS bits set, otherwise it is just the set of CPUs that
  68  *  ACPI reports present at boot.
  69  *
  70  *  If HOTPLUG is enabled, then cpu_present_mask varies dynamically,
  71  *  depending on what ACPI reports as currently plugged in, otherwise
  72  *  cpu_present_mask is just a copy of cpu_possible_mask.
  73  *
  74  *  (*) Well, cpu_present_mask is dynamic in the hotplug case.  If not
  75  *      hotplug, it's a copy of cpu_possible_mask, hence fixed at boot.
  76  *
  77  * Subtleties:
  78  * 1) UP arch's (NR_CPUS == 1, CONFIG_SMP not defined) hardcode
  79  *    assumption that their single CPU is online.  The UP
  80  *    cpu_{online,possible,present}_masks are placebos.  Changing them
  81  *    will have no useful affect on the following num_*_cpus()
  82  *    and cpu_*() macros in the UP case.  This ugliness is a UP
  83  *    optimization - don't waste any instructions or memory references
  84  *    asking if you're online or how many CPUs there are if there is
  85  *    only one CPU.
  86  */
  87
  88 extern const struct cpumask *const cpu_possible_mask;
  89 extern const struct cpumask *const cpu_online_mask;
  90 extern const struct cpumask *const cpu_present_mask;
  91 extern const struct cpumask *const cpu_active_mask;
  92
  93 #if NR_CPUS > 1
  94 #define num_online_cpus()       cpumask_weight(cpu_online_mask)
  95 #define num_possible_cpus()     cpumask_weight(cpu_possible_mask)
  96 #define num_present_cpus()      cpumask_weight(cpu_present_mask)
  97 #define num_active_cpus()       cpumask_weight(cpu_active_mask)
  98 #define cpu_online(cpu)         cpumask_test_cpu((cpu), cpu_online_mask)
  99 #define cpu_possible(cpu)       cpumask_test_cpu((cpu), cpu_possible_mask)
 100 #define cpu_present(cpu)        cpumask_test_cpu((cpu), cpu_present_mask)
 101 #define cpu_active(cpu)         cpumask_test_cpu((cpu), cpu_active_mask)
 102 #ifdef CONFIG_SCHED_HMP
 103 extern struct cpumask hmp_slow_cpu_mask;
 104 extern struct cpumask hmp_fast_cpu_mask;
 105 #define num_hmp_fast_cpus()     cpumask_weight(&hmp_fast_cpu_mask)
 106 #define num_hmp_slow_cpus()     cpumask_weight(&hmp_slow_cpu_mask)
 107 #endif
 108 #else
 109 #define num_online_cpus()       1U
 110 #define num_possible_cpus()     1U
 111 #define num_present_cpus()      1U
 112 #define num_active_cpus()       1U
 113 #define cpu_online(cpu)         ((cpu) == 0)
 114 #define cpu_possible(cpu)       ((cpu) == 0)
 115 #define cpu_present(cpu)        ((cpu) == 0)
 116 #define cpu_active(cpu)         ((cpu) == 0)
 117 #endif
 118
 119 /* verify cpu argument to cpumask_* operators */
 120 static inline unsigned int cpumask_check(unsigned int cpu)
 121 {
 122 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
 123         WARN_ON_ONCE(cpu >= nr_cpumask_bits);
 124 #endif /* CONFIG_DEBUG_PER_CPU_MAPS */
 125         return cpu;
 126 }
 127
 128 #if NR_CPUS == 1
 129 /* Uniprocessor.  Assume all masks are "1". */
 130 static inline unsigned int cpumask_first(const struct cpumask *srcp)
 131 {
 132         return 0;
 133 }
 134
 135 /* Valid inputs for n are -1 and 0. */
 136 static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
 137 {
 138         return n+1;
 139 }
 140
 141 static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
 142 {
 143         return n+1;
 144 }
 145
 146 static inline unsigned int cpumask_next_and(int n,
 147                                             const struct cpumask *srcp,
 148                                             const struct cpumask *andp)
 149 {
 150         return n+1;
 151 }
 152
 153 /* cpu must be a valid cpu, ie 0, so there's no other choice. */
 154 static inline unsigned int cpumask_any_but(const struct cpumask *mask,
 155                                            unsigned int cpu)
 156 {
 157         return 1;
 158 }
 159
 160 static inline unsigned int cpumask_local_spread(unsigned int i, int node)
 161 {
 162         return 0;
 163 }
 164
 165 #define for_each_cpu(cpu, mask)                 \
 166         for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
 167 #define for_each_cpu_not(cpu, mask)             \
 168         for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
 169 #define for_each_cpu_and(cpu, mask, and)        \
 170         for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask, (void)and)
 171 #else
 172 /**
 173  * cpumask_first - get the first cpu in a cpumask
 174  * @srcp: the cpumask pointer
 175  *
 176  * Returns >= nr_cpu_ids if no cpus set.
 177  */
 178 static inline unsigned int cpumask_first(const struct cpumask *srcp)
 179 {
 180         return find_first_bit(cpumask_bits(srcp), nr_cpumask_bits);
 181 }
 182
 183 /**
 184  * cpumask_next - get the next cpu in a cpumask
 185  * @n: the cpu prior to the place to search (ie. return will be > @n)
 186  * @srcp: the cpumask pointer
 187  *
 188  * Returns >= nr_cpu_ids if no further cpus set.
 189  */
 190 static inline unsigned int cpumask_next(int n, const struct cpumask *srcp)
 191 {
 192         /* -1 is a legal arg here. */
 193         if (n != -1)
 194                 cpumask_check(n);
 195         return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
 196 }
 197
 198 /**
 199  * cpumask_next_zero - get the next unset cpu in a cpumask
 200  * @n: the cpu prior to the place to search (ie. return will be > @n)
 201  * @srcp: the cpumask pointer
 202  *
 203  * Returns >= nr_cpu_ids if no further cpus unset.
 204  */
 205 static inline unsigned int cpumask_next_zero(int n, const struct cpumask *srcp)
 206 {
 207         /* -1 is a legal arg here. */
 208         if (n != -1)
 209                 cpumask_check(n);
 210         return find_next_zero_bit(cpumask_bits(srcp), nr_cpumask_bits, n+1);
 211 }
 212
 213 int cpumask_next_and(int n, const struct cpumask *, const struct cpumask *);
 214 int cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
 215 unsigned int cpumask_local_spread(unsigned int i, int node);
 216
 217 /**
 218  * for_each_cpu - iterate over every cpu in a mask
 219  * @cpu: the (optionally unsigned) integer iterator
 220  * @mask: the cpumask pointer
 221  *
 222  * After the loop, cpu is >= nr_cpu_ids.
 223  */
 224 #define for_each_cpu(cpu, mask)                         \
 225         for ((cpu) = -1;                                \
 226                 (cpu) = cpumask_next((cpu), (mask)),    \
 227                 (cpu) < nr_cpu_ids;)
 228
 229 /**
 230  * for_each_cpu_not - iterate over every cpu in a complemented mask
 231  * @cpu: the (optionally unsigned) integer iterator
 232  * @mask: the cpumask pointer
 233  *
 234  * After the loop, cpu is >= nr_cpu_ids.
 235  */
 236 #define for_each_cpu_not(cpu, mask)                             \
 237         for ((cpu) = -1;                                        \
 238                 (cpu) = cpumask_next_zero((cpu), (mask)),       \
 239                 (cpu) < nr_cpu_ids;)
 240
 241 /**
 242  * for_each_cpu_and - iterate over every cpu in both masks
 243  * @cpu: the (optionally unsigned) integer iterator
 244  * @mask: the first cpumask pointer
 245  * @and: the second cpumask pointer
 246  *
 247  * This saves a temporary CPU mask in many places.  It is equivalent to:
 248  *      struct cpumask tmp;
 249  *      cpumask_and(&tmp, &mask, &and);
 250  *      for_each_cpu(cpu, &tmp)
 251  *              ...
 252  *
 253  * After the loop, cpu is >= nr_cpu_ids.
 254  */
 255 #define for_each_cpu_and(cpu, mask, and)                                \
 256         for ((cpu) = -1;                                                \
 257                 (cpu) = cpumask_next_and((cpu), (mask), (and)),         \
 258                 (cpu) < nr_cpu_ids;)
 259 #endif /* SMP */
 260
 261 #define CPU_BITS_NONE                                           \
 262 {                                                               \
 263         [0 ... BITS_TO_LONGS(NR_CPUS)-1] = 0UL                  \
 264 }
 265
 266 #define CPU_BITS_CPU0                                           \
 267 {                                                               \
 268         [0] =  1UL                                              \
 269 }
 270
 271 /**
 272  * cpumask_set_cpu - set a cpu in a cpumask
 273  * @cpu: cpu number (< nr_cpu_ids)
 274  * @dstp: the cpumask pointer
 275  */
 276 static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
 277 {
 278         set_bit(cpumask_check(cpu), cpumask_bits(dstp));
 279 }
 280
 281 /**
 282  * cpumask_clear_cpu - clear a cpu in a cpumask
 283  * @cpu: cpu number (< nr_cpu_ids)
 284  * @dstp: the cpumask pointer
 285  */
 286 static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp)
 287 {
 288         clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
 289 }
 290
 291 /**
 292  * cpumask_test_cpu - test for a cpu in a cpumask
 293  * @cpu: cpu number (< nr_cpu_ids)
 294  * @cpumask: the cpumask pointer
 295  *
 296  * Returns 1 if @cpu is set in @cpumask, else returns 0
 297  */
 298 static inline int cpumask_test_cpu(int cpu, const struct cpumask *cpumask)
 299 {
 300         return test_bit(cpumask_check(cpu), cpumask_bits((cpumask)));
 301 }
 302
 303 /**
 304  * cpumask_test_and_set_cpu - atomically test and set a cpu in a cpumask
 305  * @cpu: cpu number (< nr_cpu_ids)
 306  * @cpumask: the cpumask pointer
 307  *
 308  * Returns 1 if @cpu is set in old bitmap of @cpumask, else returns 0
 309  *
 310  * test_and_set_bit wrapper for cpumasks.
 311  */
 312 static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask)
 313 {
 314         return test_and_set_bit(cpumask_check(cpu), cpumask_bits(cpumask));
 315 }
 316
 317 /**
 318  * cpumask_test_and_clear_cpu - atomically test and clear a cpu in a cpumask
 319  * @cpu: cpu number (< nr_cpu_ids)
 320  * @cpumask: the cpumask pointer
 321  *
 322  * Returns 1 if @cpu is set in old bitmap of @cpumask, else returns 0
 323  *
 324  * test_and_clear_bit wrapper for cpumasks.
 325  */
 326 static inline int cpumask_test_and_clear_cpu(int cpu, struct cpumask *cpumask)
 327 {
 328         return test_and_clear_bit(cpumask_check(cpu), cpumask_bits(cpumask));
 329 }
 330
 331 /**
 332  * cpumask_setall - set all cpus (< nr_cpu_ids) in a cpumask
 333  * @dstp: the cpumask pointer
 334  */
 335 static inline void cpumask_setall(struct cpumask *dstp)
 336 {
 337         bitmap_fill(cpumask_bits(dstp), nr_cpumask_bits);
 338 }
 339
 340 /**
 341  * cpumask_clear - clear all cpus (< nr_cpu_ids) in a cpumask
 342  * @dstp: the cpumask pointer
 343  */
 344 static inline void cpumask_clear(struct cpumask *dstp)
 345 {
 346         bitmap_zero(cpumask_bits(dstp), nr_cpumask_bits);
 347 }
 348
 349 /**
 350  * cpumask_and - *dstp = *src1p & *src2p
 351  * @dstp: the cpumask result
 352  * @src1p: the first input
 353  * @src2p: the second input
 354  *
 355  * If *@dstp is empty, returns 0, else returns 1
 356  */
 357 static inline int cpumask_and(struct cpumask *dstp,
 358                                const struct cpumask *src1p,
 359                                const struct cpumask *src2p)
 360 {
 361         return bitmap_and(cpumask_bits(dstp), cpumask_bits(src1p),
 362                                        cpumask_bits(src2p), nr_cpumask_bits);
 363 }
 364
 365 /**
 366  * cpumask_or - *dstp = *src1p | *src2p
 367  * @dstp: the cpumask result
 368  * @src1p: the first input
 369  * @src2p: the second input
 370  */
 371 static inline void cpumask_or(struct cpumask *dstp, const struct cpumask *src1p,
 372                               const struct cpumask *src2p)
 373 {
 374         bitmap_or(cpumask_bits(dstp), cpumask_bits(src1p),
 375                                       cpumask_bits(src2p), nr_cpumask_bits);
 376 }
 377
 378 /**
 379  * cpumask_xor - *dstp = *src1p ^ *src2p
 380  * @dstp: the cpumask result
 381  * @src1p: the first input
 382  * @src2p: the second input
 383  */
 384 static inline void cpumask_xor(struct cpumask *dstp,
 385                                const struct cpumask *src1p,
 386                                const struct cpumask *src2p)
 387 {
 388         bitmap_xor(cpumask_bits(dstp), cpumask_bits(src1p),
 389                                        cpumask_bits(src2p), nr_cpumask_bits);
 390 }
 391
 392 /**
 393  * cpumask_andnot - *dstp = *src1p & ~*src2p
 394  * @dstp: the cpumask result
 395  * @src1p: the first input
 396  * @src2p: the second input
 397  *
 398  * If *@dstp is empty, returns 0, else returns 1
 399  */
 400 static inline int cpumask_andnot(struct cpumask *dstp,
 401                                   const struct cpumask *src1p,
 402                                   const struct cpumask *src2p)
 403 {
 404         return bitmap_andnot(cpumask_bits(dstp), cpumask_bits(src1p),
 405                                           cpumask_bits(src2p), nr_cpumask_bits);
 406 }
 407
 408 /**
 409  * cpumask_complement - *dstp = ~*srcp
 410  * @dstp: the cpumask result
 411  * @srcp: the input to invert
 412  */
 413 static inline void cpumask_complement(struct cpumask *dstp,
 414                                       const struct cpumask *srcp)
 415 {
 416         bitmap_complement(cpumask_bits(dstp), cpumask_bits(srcp),
 417                                               nr_cpumask_bits);
 418 }
 419
 420 /**
 421  * cpumask_equal - *src1p == *src2p
 422  * @src1p: the first input
 423  * @src2p: the second input
 424  */
 425 static inline bool cpumask_equal(const struct cpumask *src1p,
 426                                 const struct cpumask *src2p)
 427 {
 428         return bitmap_equal(cpumask_bits(src1p), cpumask_bits(src2p),
 429                                                  nr_cpumask_bits);
 430 }
 431
 432 /**
 433  * cpumask_intersects - (*src1p & *src2p) != 0
 434  * @src1p: the first input
 435  * @src2p: the second input
 436  */
 437 static inline bool cpumask_intersects(const struct cpumask *src1p,
 438                                      const struct cpumask *src2p)
 439 {
 440         return bitmap_intersects(cpumask_bits(src1p), cpumask_bits(src2p),
 441                                                       nr_cpumask_bits);
 442 }
 443
 444 /**
 445  * cpumask_subset - (*src1p & ~*src2p) == 0
 446  * @src1p: the first input
 447  * @src2p: the second input
 448  *
 449  * Returns 1 if *@src1p is a subset of *@src2p, else returns 0
 450  */
 451 static inline int cpumask_subset(const struct cpumask *src1p,
 452                                  const struct cpumask *src2p)
 453 {
 454         return bitmap_subset(cpumask_bits(src1p), cpumask_bits(src2p),
 455                                                   nr_cpumask_bits);
 456 }
 457
 458 /**
 459  * cpumask_empty - *srcp == 0
 460  * @srcp: the cpumask to that all cpus < nr_cpu_ids are clear.
 461  */
 462 static inline bool cpumask_empty(const struct cpumask *srcp)
 463 {
 464         return bitmap_empty(cpumask_bits(srcp), nr_cpumask_bits);
 465 }
 466
 467 /**
 468  * cpumask_full - *srcp == 0xFFFFFFFF...
 469  * @srcp: the cpumask to that all cpus < nr_cpu_ids are set.
 470  */
 471 static inline bool cpumask_full(const struct cpumask *srcp)
 472 {
 473         return bitmap_full(cpumask_bits(srcp), nr_cpumask_bits);
 474 }
 475
 476 /**
 477  * cpumask_weight - Count of bits in *srcp
 478  * @srcp: the cpumask to count bits (< nr_cpu_ids) in.
 479  */
 480 static inline unsigned int cpumask_weight(const struct cpumask *srcp)
 481 {
 482         return bitmap_weight(cpumask_bits(srcp), nr_cpumask_bits);
 483 }
 484
 485 /**
 486  * cpumask_shift_right - *dstp = *srcp >> n
 487  * @dstp: the cpumask result
 488  * @srcp: the input to shift
 489  * @n: the number of bits to shift by
 490  */
 491 static inline void cpumask_shift_right(struct cpumask *dstp,
 492                                        const struct cpumask *srcp, int n)
 493 {
 494         bitmap_shift_right(cpumask_bits(dstp), cpumask_bits(srcp), n,
 495                                                nr_cpumask_bits);
 496 }
 497
 498 /**
 499  * cpumask_shift_left - *dstp = *srcp << n
 500  * @dstp: the cpumask result
 501  * @srcp: the input to shift
 502  * @n: the number of bits to shift by
 503  */
 504 static inline void cpumask_shift_left(struct cpumask *dstp,
 505                                       const struct cpumask *srcp, int n)
 506 {
 507         bitmap_shift_left(cpumask_bits(dstp), cpumask_bits(srcp), n,
 508                                               nr_cpumask_bits);
 509 }
 510
 511 /**
 512  * cpumask_copy - *dstp = *srcp
 513  * @dstp: the result
 514  * @srcp: the input cpumask
 515  */
 516 static inline void cpumask_copy(struct cpumask *dstp,
 517                                 const struct cpumask *srcp)
 518 {
 519         bitmap_copy(cpumask_bits(dstp), cpumask_bits(srcp), nr_cpumask_bits);
 520 }
 521
 522 /**
 523  * cpumask_any - pick a "random" cpu from *srcp
 524  * @srcp: the input cpumask
 525  *
 526  * Returns >= nr_cpu_ids if no cpus set.
 527  */
 528 #define cpumask_any(srcp) cpumask_first(srcp)
 529
 530 /**
 531  * cpumask_first_and - return the first cpu from *srcp1 & *srcp2
 532  * @src1p: the first input
 533  * @src2p: the second input
 534  *
 535  * Returns >= nr_cpu_ids if no cpus set in both.  See also cpumask_next_and().
 536  */
 537 #define cpumask_first_and(src1p, src2p) cpumask_next_and(-1, (src1p), (src2p))
 538
 539 /**
 540  * cpumask_any_and - pick a "random" cpu from *mask1 & *mask2
 541  * @mask1: the first input cpumask
 542  * @mask2: the second input cpumask
 543  *
 544  * Returns >= nr_cpu_ids if no cpus set.
 545  */
 546 #define cpumask_any_and(mask1, mask2) cpumask_first_and((mask1), (mask2))
 547
 548 /**
 549  * cpumask_of - the cpumask containing just a given cpu
 550  * @cpu: the cpu (<= nr_cpu_ids)
 551  */
 552 #define cpumask_of(cpu) (get_cpu_mask(cpu))
 553
 554 /**
 555  * cpumask_parse_user - extract a cpumask from a user string
 556  * @buf: the buffer to extract from
 557  * @len: the length of the buffer
 558  * @dstp: the cpumask to set.
 559  *
 560  * Returns -errno, or 0 for success.
 561  */
 562 static inline int cpumask_parse_user(const char __user *buf, int len,
 563                                      struct cpumask *dstp)
 564 {
 565         return bitmap_parse_user(buf, len, cpumask_bits(dstp), nr_cpumask_bits);
 566 }
 567
 568 /**
 569  * cpumask_parselist_user - extract a cpumask from a user string
 570  * @buf: the buffer to extract from
 571  * @len: the length of the buffer
 572  * @dstp: the cpumask to set.
 573  *
 574  * Returns -errno, or 0 for success.
 575  */
 576 static inline int cpumask_parselist_user(const char __user *buf, int len,
 577                                      struct cpumask *dstp)
 578 {
 579         return bitmap_parselist_user(buf, len, cpumask_bits(dstp),
 580                                      nr_cpumask_bits);
 581 }
 582
 583 /**
 584  * cpumask_parse - extract a cpumask from from a string
 585  * @buf: the buffer to extract from
 586  * @dstp: the cpumask to set.
 587  *
 588  * Returns -errno, or 0 for success.
 589  */
 590 static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
 591 {
 592         char *nl = strchr(buf, '\n');
 593         unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf);
 594
 595         return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits);
 596 }
 597
 598 /**
 599  * cpulist_parse - extract a cpumask from a user string of ranges
 600  * @buf: the buffer to extract from
 601  * @dstp: the cpumask to set.
 602  *
 603  * Returns -errno, or 0 for success.
 604  */
 605 static inline int cpulist_parse(const char *buf, struct cpumask *dstp)
 606 {
 607         return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpumask_bits);
 608 }
 609
 610 /**
 611  * cpumask_size - size to allocate for a 'struct cpumask' in bytes
 612  *
 613  * This will eventually be a runtime variable, depending on nr_cpu_ids.
 614  */
 615 static inline size_t cpumask_size(void)
 616 {
 617         return BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long);
 618 }
 619
 620 /*
 621  * cpumask_var_t: struct cpumask for stack usage.
 622  *
 623  * Oh, the wicked games we play!  In order to make kernel coding a
 624  * little more difficult, we typedef cpumask_var_t to an array or a
 625  * pointer: doing &mask on an array is a noop, so it still works.
 626  *
 627  * ie.
 628  *      cpumask_var_t tmpmask;
 629  *      if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
 630  *              return -ENOMEM;
 631  *
 632  *        ... use 'tmpmask' like a normal struct cpumask * ...
 633  *
 634  *      free_cpumask_var(tmpmask);
 635  *
 636  *
 637  * However, one notable exception is there. alloc_cpumask_var() allocates
 638  * only nr_cpumask_bits bits (in the other hand, real cpumask_t always has
 639  * NR_CPUS bits). Therefore you don't have to dereference cpumask_var_t.
 640  *
 641  *      cpumask_var_t tmpmask;
 642  *      if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL))
 643  *              return -ENOMEM;
 644  *
 645  *      var = *tmpmask;
 646  *
 647  * This code makes NR_CPUS length memcopy and brings to a memory corruption.
 648  * cpumask_copy() provide safe copy functionality.
 649  *
 650  * Note that there is another evil here: If you define a cpumask_var_t
 651  * as a percpu variable then the way to obtain the address of the cpumask
 652  * structure differently influences what this_cpu_* operation needs to be
 653  * used. Please use this_cpu_cpumask_var_t in those cases. The direct use
 654  * of this_cpu_ptr() or this_cpu_read() will lead to failures when the
 655  * other type of cpumask_var_t implementation is configured.
 656  */
 657 #ifdef CONFIG_CPUMASK_OFFSTACK
 658 typedef struct cpumask *cpumask_var_t;
 659
 660 #define this_cpu_cpumask_var_ptr(x) this_cpu_read(x)
 661
 662 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node);
 663 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags);
 664 bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node);
 665 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags);
 666 void alloc_bootmem_cpumask_var(cpumask_var_t *mask);
 667 void free_cpumask_var(cpumask_var_t mask);
 668 void free_bootmem_cpumask_var(cpumask_var_t mask);
 669
 670 static inline bool cpumask_available(cpumask_var_t mask)
 671 {
 672         return mask != NULL;
 673 }
 674
 675 #else
 676 typedef struct cpumask cpumask_var_t[1];
 677
 678 #define this_cpu_cpumask_var_ptr(x) this_cpu_ptr(x)
 679
 680 static inline bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 681 {
 682         return true;
 683 }
 684
 685 static inline bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags,
 686                                           int node)
 687 {
 688         return true;
 689 }
 690
 691 static inline bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 692 {
 693         cpumask_clear(*mask);
 694         return true;
 695 }
 696
 697 static inline bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags,
 698                                           int node)
 699 {
 700         cpumask_clear(*mask);
 701         return true;
 702 }
 703
 704 static inline void alloc_bootmem_cpumask_var(cpumask_var_t *mask)
 705 {
 706 }
 707
 708 static inline void free_cpumask_var(cpumask_var_t mask)
 709 {
 710 }
 711
 712 static inline void free_bootmem_cpumask_var(cpumask_var_t mask)
 713 {
 714 }
 715
 716 static inline bool cpumask_available(cpumask_var_t mask)
 717 {
 718         return true;
 719 }
 720 #endif /* CONFIG_CPUMASK_OFFSTACK */
 721
 722 /* It's common to want to use cpu_all_mask in struct member initializers,
 723  * so it has to refer to an address rather than a pointer. */
 724 extern const DECLARE_BITMAP(cpu_all_bits, NR_CPUS);
 725 #define cpu_all_mask to_cpumask(cpu_all_bits)
 726
 727 /* First bits of cpu_bit_bitmap are in fact unset. */
 728 #define cpu_none_mask to_cpumask(cpu_bit_bitmap[0])
 729
 730 #define for_each_possible_cpu(cpu) for_each_cpu((cpu), cpu_possible_mask)
 731 #define for_each_online_cpu(cpu)   for_each_cpu((cpu), cpu_online_mask)
 732 #define for_each_present_cpu(cpu)  for_each_cpu((cpu), cpu_present_mask)
 733
 734 /* Wrappers for arch boot code to manipulate normally-constant masks */
 735 void set_cpu_possible(unsigned int cpu, bool possible);
 736 void set_cpu_present(unsigned int cpu, bool present);
 737 void set_cpu_online(unsigned int cpu, bool online);
 738 void set_cpu_active(unsigned int cpu, bool active);
 739 void init_cpu_present(const struct cpumask *src);
 740 void init_cpu_possible(const struct cpumask *src);
 741 void init_cpu_online(const struct cpumask *src);
 742
 743 /**
 744  * to_cpumask - convert an NR_CPUS bitmap to a struct cpumask *
 745  * @bitmap: the bitmap
 746  *
 747  * There are a few places where cpumask_var_t isn't appropriate and
 748  * static cpumasks must be used (eg. very early boot), yet we don't
 749  * expose the definition of 'struct cpumask'.
 750  *
 751  * This does the conversion, and can be used as a constant initializer.
 752  */
 753 #define to_cpumask(bitmap)                                              \
 754         ((struct cpumask *)(1 ? (bitmap)                                \
 755                             : (void *)sizeof(__check_is_bitmap(bitmap))))
 756
 757 static inline int __check_is_bitmap(const unsigned long *bitmap)
 758 {
 759         return 1;
 760 }
 761
 762 /*
 763  * Special-case data structure for "single bit set only" constant CPU masks.
 764  *
 765  * We pre-generate all the 64 (or 32) possible bit positions, with enough
 766  * padding to the left and the right, and return the constant pointer
 767  * appropriately offset.
 768  */
 769 extern const unsigned long
 770         cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)];
 771
 772 static inline const struct cpumask *get_cpu_mask(unsigned int cpu)
 773 {
 774         const unsigned long *p = cpu_bit_bitmap[1 + cpu % BITS_PER_LONG];
 775         p -= cpu / BITS_PER_LONG;
 776         return to_cpumask(p);
 777 }
 778
 779 #define cpu_is_offline(cpu)     unlikely(!cpu_online(cpu))
 780
 781 #if NR_CPUS <= BITS_PER_LONG
 782 #define CPU_BITS_ALL                                            \
 783 {                                                               \
 784         [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 785 }
 786
 787 #else /* NR_CPUS > BITS_PER_LONG */
 788
 789 #define CPU_BITS_ALL                                            \
 790 {                                                               \
 791         [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL,                \
 792         [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 793 }
 794 #endif /* NR_CPUS > BITS_PER_LONG */
 795
 796 /**
 797  * cpumap_print_to_pagebuf  - copies the cpumask into the buffer either
 798  *      as comma-separated list of cpus or hex values of cpumask
 799  * @list: indicates whether the cpumap must be list
 800  * @mask: the cpumask to copy
 801  * @buf: the buffer to copy into
 802  *
 803  * Returns the length of the (null-terminated) @buf string, zero if
 804  * nothing is copied.
 805  */
 806 static inline ssize_t
 807 cpumap_print_to_pagebuf(bool list, char *buf, const struct cpumask *mask)
 808 {
 809         return bitmap_print_to_pagebuf(list, buf, cpumask_bits(mask),
 810                                       nr_cpu_ids);
 811 }
 812
 813 #if NR_CPUS <= BITS_PER_LONG
 814 #define CPU_MASK_ALL                                                    \
 815 (cpumask_t) { {                                                         \
 816         [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 817 } }
 818 #else
 819 #define CPU_MASK_ALL                                                    \
 820 (cpumask_t) { {                                                         \
 821         [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL,                        \
 822         [BITS_TO_LONGS(NR_CPUS)-1] = BITMAP_LAST_WORD_MASK(NR_CPUS)     \
 823 } }
 824 #endif /* NR_CPUS > BITS_PER_LONG */
 825
 826 #define CPU_MASK_NONE                                                   \
 827 (cpumask_t) { {                                                         \
 828         [0 ... BITS_TO_LONGS(NR_CPUS)-1] =  0UL                         \
 829 } }
 830
 831 #define CPU_MASK_CPU0                                                   \
 832 (cpumask_t) { {                                                         \
 833         [0] =  1UL                                                      \
 834 } }
 835
 836 #endif /* __LINUX_CPUMASK_H */