linux/mm/percpu.c
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   1/*
   2 * mm/percpu.c - percpu memory allocator
   3 *
   4 * Copyright (C) 2009           SUSE Linux Products GmbH
   5 * Copyright (C) 2009           Tejun Heo <tj@kernel.org>
   6 *
   7 * This file is released under the GPLv2.
   8 *
   9 * This is percpu allocator which can handle both static and dynamic
  10 * areas.  Percpu areas are allocated in chunks.  Each chunk is
  11 * consisted of boot-time determined number of units and the first
  12 * chunk is used for static percpu variables in the kernel image
  13 * (special boot time alloc/init handling necessary as these areas
  14 * need to be brought up before allocation services are running).
  15 * Unit grows as necessary and all units grow or shrink in unison.
  16 * When a chunk is filled up, another chunk is allocated.
  17 *
  18 *  c0                           c1                         c2
  19 *  -------------------          -------------------        ------------
  20 * | u0 | u1 | u2 | u3 |        | u0 | u1 | u2 | u3 |      | u0 | u1 | u
  21 *  -------------------  ......  -------------------  ....  ------------
  22 *
  23 * Allocation is done in offset-size areas of single unit space.  Ie,
  24 * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
  25 * c1:u1, c1:u2 and c1:u3.  On UMA, units corresponds directly to
  26 * cpus.  On NUMA, the mapping can be non-linear and even sparse.
  27 * Percpu access can be done by configuring percpu base registers
  28 * according to cpu to unit mapping and pcpu_unit_size.
  29 *
  30 * There are usually many small percpu allocations many of them being
  31 * as small as 4 bytes.  The allocator organizes chunks into lists
  32 * according to free size and tries to allocate from the fullest one.
  33 * Each chunk keeps the maximum contiguous area size hint which is
  34 * guaranteed to be equal to or larger than the maximum contiguous
  35 * area in the chunk.  This helps the allocator not to iterate the
  36 * chunk maps unnecessarily.
  37 *
  38 * Allocation state in each chunk is kept using an array of integers
  39 * on chunk->map.  A positive value in the map represents a free
  40 * region and negative allocated.  Allocation inside a chunk is done
  41 * by scanning this map sequentially and serving the first matching
  42 * entry.  This is mostly copied from the percpu_modalloc() allocator.
  43 * Chunks can be determined from the address using the index field
  44 * in the page struct. The index field contains a pointer to the chunk.
  45 *
  46 * To use this allocator, arch code should do the followings.
  47 *
  48 * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
  49 *   regular address to percpu pointer and back if they need to be
  50 *   different from the default
  51 *
  52 * - use pcpu_setup_first_chunk() during percpu area initialization to
  53 *   setup the first chunk containing the kernel static percpu area
  54 */
  55
  56#include <linux/bitmap.h>
  57#include <linux/bootmem.h>
  58#include <linux/err.h>
  59#include <linux/list.h>
  60#include <linux/log2.h>
  61#include <linux/mm.h>
  62#include <linux/module.h>
  63#include <linux/mutex.h>
  64#include <linux/percpu.h>
  65#include <linux/pfn.h>
  66#include <linux/slab.h>
  67#include <linux/spinlock.h>
  68#include <linux/vmalloc.h>
  69#include <linux/workqueue.h>
  70#include <linux/kmemleak.h>
  71
  72#include <asm/cacheflush.h>
  73#include <asm/sections.h>
  74#include <asm/tlbflush.h>
  75#include <asm/io.h>
  76
  77#define PCPU_SLOT_BASE_SHIFT            5       /* 1-31 shares the same slot */
  78#define PCPU_DFL_MAP_ALLOC              16      /* start a map with 16 ents */
  79
  80#ifdef CONFIG_SMP
  81/* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */
  82#ifndef __addr_to_pcpu_ptr
  83#define __addr_to_pcpu_ptr(addr)                                        \
  84        (void __percpu *)((unsigned long)(addr) -                       \
  85                          (unsigned long)pcpu_base_addr +               \
  86                          (unsigned long)__per_cpu_start)
  87#endif
  88#ifndef __pcpu_ptr_to_addr
  89#define __pcpu_ptr_to_addr(ptr)                                         \
  90        (void __force *)((unsigned long)(ptr) +                         \
  91                         (unsigned long)pcpu_base_addr -                \
  92                         (unsigned long)__per_cpu_start)
  93#endif
  94#else   /* CONFIG_SMP */
  95/* on UP, it's always identity mapped */
  96#define __addr_to_pcpu_ptr(addr)        (void __percpu *)(addr)
  97#define __pcpu_ptr_to_addr(ptr)         (void __force *)(ptr)
  98#endif  /* CONFIG_SMP */
  99
 100struct pcpu_chunk {
 101        struct list_head        list;           /* linked to pcpu_slot lists */
 102        int                     free_size;      /* free bytes in the chunk */
 103        int                     contig_hint;    /* max contiguous size hint */
 104        void                    *base_addr;     /* base address of this chunk */
 105        int                     map_used;       /* # of map entries used */
 106        int                     map_alloc;      /* # of map entries allocated */
 107        int                     *map;           /* allocation map */
 108        void                    *data;          /* chunk data */
 109        bool                    immutable;      /* no [de]population allowed */
 110        unsigned long           populated[];    /* populated bitmap */
 111};
 112
 113static int pcpu_unit_pages __read_mostly;
 114static int pcpu_unit_size __read_mostly;
 115static int pcpu_nr_units __read_mostly;
 116static int pcpu_atom_size __read_mostly;
 117static int pcpu_nr_slots __read_mostly;
 118static size_t pcpu_chunk_struct_size __read_mostly;
 119
 120/* cpus with the lowest and highest unit addresses */
 121static unsigned int pcpu_low_unit_cpu __read_mostly;
 122static unsigned int pcpu_high_unit_cpu __read_mostly;
 123
 124/* the address of the first chunk which starts with the kernel static area */
 125void *pcpu_base_addr __read_mostly;
 126EXPORT_SYMBOL_GPL(pcpu_base_addr);
 127
 128static const int *pcpu_unit_map __read_mostly;          /* cpu -> unit */
 129const unsigned long *pcpu_unit_offsets __read_mostly;   /* cpu -> unit offset */
 130
 131/* group information, used for vm allocation */
 132static int pcpu_nr_groups __read_mostly;
 133static const unsigned long *pcpu_group_offsets __read_mostly;
 134static const size_t *pcpu_group_sizes __read_mostly;
 135
 136/*
 137 * The first chunk which always exists.  Note that unlike other
 138 * chunks, this one can be allocated and mapped in several different
 139 * ways and thus often doesn't live in the vmalloc area.
 140 */
 141static struct pcpu_chunk *pcpu_first_chunk;
 142
 143/*
 144 * Optional reserved chunk.  This chunk reserves part of the first
 145 * chunk and serves it for reserved allocations.  The amount of
 146 * reserved offset is in pcpu_reserved_chunk_limit.  When reserved
 147 * area doesn't exist, the following variables contain NULL and 0
 148 * respectively.
 149 */
 150static struct pcpu_chunk *pcpu_reserved_chunk;
 151static int pcpu_reserved_chunk_limit;
 152
 153/*
 154 * Synchronization rules.
 155 *
 156 * There are two locks - pcpu_alloc_mutex and pcpu_lock.  The former
 157 * protects allocation/reclaim paths, chunks, populated bitmap and
 158 * vmalloc mapping.  The latter is a spinlock and protects the index
 159 * data structures - chunk slots, chunks and area maps in chunks.
 160 *
 161 * During allocation, pcpu_alloc_mutex is kept locked all the time and
 162 * pcpu_lock is grabbed and released as necessary.  All actual memory
 163 * allocations are done using GFP_KERNEL with pcpu_lock released.  In
 164 * general, percpu memory can't be allocated with irq off but
 165 * irqsave/restore are still used in alloc path so that it can be used
 166 * from early init path - sched_init() specifically.
 167 *
 168 * Free path accesses and alters only the index data structures, so it
 169 * can be safely called from atomic context.  When memory needs to be
 170 * returned to the system, free path schedules reclaim_work which
 171 * grabs both pcpu_alloc_mutex and pcpu_lock, unlinks chunks to be
 172 * reclaimed, release both locks and frees the chunks.  Note that it's
 173 * necessary to grab both locks to remove a chunk from circulation as
 174 * allocation path might be referencing the chunk with only
 175 * pcpu_alloc_mutex locked.
 176 */
 177static DEFINE_MUTEX(pcpu_alloc_mutex);  /* protects whole alloc and reclaim */
 178static DEFINE_SPINLOCK(pcpu_lock);      /* protects index data structures */
 179
 180static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */
 181
 182/* reclaim work to release fully free chunks, scheduled from free path */
 183static void pcpu_reclaim(struct work_struct *work);
 184static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim);
 185
 186static bool pcpu_addr_in_first_chunk(void *addr)
 187{
 188        void *first_start = pcpu_first_chunk->base_addr;
 189
 190        return addr >= first_start && addr < first_start + pcpu_unit_size;
 191}
 192
 193static bool pcpu_addr_in_reserved_chunk(void *addr)
 194{
 195        void *first_start = pcpu_first_chunk->base_addr;
 196
 197        return addr >= first_start &&
 198                addr < first_start + pcpu_reserved_chunk_limit;
 199}
 200
 201static int __pcpu_size_to_slot(int size)
 202{
 203        int highbit = fls(size);        /* size is in bytes */
 204        return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
 205}
 206
 207static int pcpu_size_to_slot(int size)
 208{
 209        if (size == pcpu_unit_size)
 210                return pcpu_nr_slots - 1;
 211        return __pcpu_size_to_slot(size);
 212}
 213
 214static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
 215{
 216        if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
 217                return 0;
 218
 219        return pcpu_size_to_slot(chunk->free_size);
 220}
 221
 222/* set the pointer to a chunk in a page struct */
 223static void pcpu_set_page_chunk(struct page *page, struct pcpu_chunk *pcpu)
 224{
 225        page->index = (unsigned long)pcpu;
 226}
 227
 228/* obtain pointer to a chunk from a page struct */
 229static struct pcpu_chunk *pcpu_get_page_chunk(struct page *page)
 230{
 231        return (struct pcpu_chunk *)page->index;
 232}
 233
 234static int __maybe_unused pcpu_page_idx(unsigned int cpu, int page_idx)
 235{
 236        return pcpu_unit_map[cpu] * pcpu_unit_pages + page_idx;
 237}
 238
 239static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
 240                                     unsigned int cpu, int page_idx)
 241{
 242        return (unsigned long)chunk->base_addr + pcpu_unit_offsets[cpu] +
 243                (page_idx << PAGE_SHIFT);
 244}
 245
 246static void __maybe_unused pcpu_next_unpop(struct pcpu_chunk *chunk,
 247                                           int *rs, int *re, int end)
 248{
 249        *rs = find_next_zero_bit(chunk->populated, end, *rs);
 250        *re = find_next_bit(chunk->populated, end, *rs + 1);
 251}
 252
 253static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
 254                                         int *rs, int *re, int end)
 255{
 256        *rs = find_next_bit(chunk->populated, end, *rs);
 257        *re = find_next_zero_bit(chunk->populated, end, *rs + 1);
 258}
 259
 260/*
 261 * (Un)populated page region iterators.  Iterate over (un)populated
 262 * page regions between @start and @end in @chunk.  @rs and @re should
 263 * be integer variables and will be set to start and end page index of
 264 * the current region.
 265 */
 266#define pcpu_for_each_unpop_region(chunk, rs, re, start, end)               \
 267        for ((rs) = (start), pcpu_next_unpop((chunk), &(rs), &(re), (end)); \
 268             (rs) < (re);                                                   \
 269             (rs) = (re) + 1, pcpu_next_unpop((chunk), &(rs), &(re), (end)))
 270
 271#define pcpu_for_each_pop_region(chunk, rs, re, start, end)                 \
 272        for ((rs) = (start), pcpu_next_pop((chunk), &(rs), &(re), (end));   \
 273             (rs) < (re);                                                   \
 274             (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
 275
 276/**
 277 * pcpu_mem_zalloc - allocate memory
 278 * @size: bytes to allocate
 279 *
 280 * Allocate @size bytes.  If @size is smaller than PAGE_SIZE,
 281 * kzalloc() is used; otherwise, vzalloc() is used.  The returned
 282 * memory is always zeroed.
 283 *
 284 * CONTEXT:
 285 * Does GFP_KERNEL allocation.
 286 *
 287 * RETURNS:
 288 * Pointer to the allocated area on success, NULL on failure.
 289 */
 290static void *pcpu_mem_zalloc(size_t size)
 291{
 292        if (WARN_ON_ONCE(!slab_is_available()))
 293                return NULL;
 294
 295        if (size <= PAGE_SIZE)
 296                return kzalloc(size, GFP_KERNEL);
 297        else
 298                return vzalloc(size);
 299}
 300
 301/**
 302 * pcpu_mem_free - free memory
 303 * @ptr: memory to free
 304 * @size: size of the area
 305 *
 306 * Free @ptr.  @ptr should have been allocated using pcpu_mem_zalloc().
 307 */
 308static void pcpu_mem_free(void *ptr, size_t size)
 309{
 310        if (size <= PAGE_SIZE)
 311                kfree(ptr);
 312        else
 313                vfree(ptr);
 314}
 315
 316/**
 317 * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
 318 * @chunk: chunk of interest
 319 * @oslot: the previous slot it was on
 320 *
 321 * This function is called after an allocation or free changed @chunk.
 322 * New slot according to the changed state is determined and @chunk is
 323 * moved to the slot.  Note that the reserved chunk is never put on
 324 * chunk slots.
 325 *
 326 * CONTEXT:
 327 * pcpu_lock.
 328 */
 329static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
 330{
 331        int nslot = pcpu_chunk_slot(chunk);
 332
 333        if (chunk != pcpu_reserved_chunk && oslot != nslot) {
 334                if (oslot < nslot)
 335                        list_move(&chunk->list, &pcpu_slot[nslot]);
 336                else
 337                        list_move_tail(&chunk->list, &pcpu_slot[nslot]);
 338        }
 339}
 340
 341/**
 342 * pcpu_need_to_extend - determine whether chunk area map needs to be extended
 343 * @chunk: chunk of interest
 344 *
 345 * Determine whether area map of @chunk needs to be extended to
 346 * accommodate a new allocation.
 347 *
 348 * CONTEXT:
 349 * pcpu_lock.
 350 *
 351 * RETURNS:
 352 * New target map allocation length if extension is necessary, 0
 353 * otherwise.
 354 */
 355static int pcpu_need_to_extend(struct pcpu_chunk *chunk)
 356{
 357        int new_alloc;
 358
 359        if (chunk->map_alloc >= chunk->map_used + 2)
 360                return 0;
 361
 362        new_alloc = PCPU_DFL_MAP_ALLOC;
 363        while (new_alloc < chunk->map_used + 2)
 364                new_alloc *= 2;
 365
 366        return new_alloc;
 367}
 368
 369/**
 370 * pcpu_extend_area_map - extend area map of a chunk
 371 * @chunk: chunk of interest
 372 * @new_alloc: new target allocation length of the area map
 373 *
 374 * Extend area map of @chunk to have @new_alloc entries.
 375 *
 376 * CONTEXT:
 377 * Does GFP_KERNEL allocation.  Grabs and releases pcpu_lock.
 378 *
 379 * RETURNS:
 380 * 0 on success, -errno on failure.
 381 */
 382static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
 383{
 384        int *old = NULL, *new = NULL;
 385        size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
 386        unsigned long flags;
 387
 388        new = pcpu_mem_zalloc(new_size);
 389        if (!new)
 390                return -ENOMEM;
 391
 392        /* acquire pcpu_lock and switch to new area map */
 393        spin_lock_irqsave(&pcpu_lock, flags);
 394
 395        if (new_alloc <= chunk->map_alloc)
 396                goto out_unlock;
 397
 398        old_size = chunk->map_alloc * sizeof(chunk->map[0]);
 399        old = chunk->map;
 400
 401        memcpy(new, old, old_size);
 402
 403        chunk->map_alloc = new_alloc;
 404        chunk->map = new;
 405        new = NULL;
 406
 407out_unlock:
 408        spin_unlock_irqrestore(&pcpu_lock, flags);
 409
 410        /*
 411         * pcpu_mem_free() might end up calling vfree() which uses
 412         * IRQ-unsafe lock and thus can't be called under pcpu_lock.
 413         */
 414        pcpu_mem_free(old, old_size);
 415        pcpu_mem_free(new, new_size);
 416
 417        return 0;
 418}
 419
 420/**
 421 * pcpu_split_block - split a map block
 422 * @chunk: chunk of interest
 423 * @i: index of map block to split
 424 * @head: head size in bytes (can be 0)
 425 * @tail: tail size in bytes (can be 0)
 426 *
 427 * Split the @i'th map block into two or three blocks.  If @head is
 428 * non-zero, @head bytes block is inserted before block @i moving it
 429 * to @i+1 and reducing its size by @head bytes.
 430 *
 431 * If @tail is non-zero, the target block, which can be @i or @i+1
 432 * depending on @head, is reduced by @tail bytes and @tail byte block
 433 * is inserted after the target block.
 434 *
 435 * @chunk->map must have enough free slots to accommodate the split.
 436 *
 437 * CONTEXT:
 438 * pcpu_lock.
 439 */
 440static void pcpu_split_block(struct pcpu_chunk *chunk, int i,
 441                             int head, int tail)
 442{
 443        int nr_extra = !!head + !!tail;
 444
 445        BUG_ON(chunk->map_alloc < chunk->map_used + nr_extra);
 446
 447        /* insert new subblocks */
 448        memmove(&chunk->map[i + nr_extra], &chunk->map[i],
 449                sizeof(chunk->map[0]) * (chunk->map_used - i));
 450        chunk->map_used += nr_extra;
 451
 452        if (head) {
 453                chunk->map[i + 1] = chunk->map[i] - head;
 454                chunk->map[i++] = head;
 455        }
 456        if (tail) {
 457                chunk->map[i++] -= tail;
 458                chunk->map[i] = tail;
 459        }
 460}
 461
 462/**
 463 * pcpu_alloc_area - allocate area from a pcpu_chunk
 464 * @chunk: chunk of interest
 465 * @size: wanted size in bytes
 466 * @align: wanted align
 467 *
 468 * Try to allocate @size bytes area aligned at @align from @chunk.
 469 * Note that this function only allocates the offset.  It doesn't
 470 * populate or map the area.
 471 *
 472 * @chunk->map must have at least two free slots.
 473 *
 474 * CONTEXT:
 475 * pcpu_lock.
 476 *
 477 * RETURNS:
 478 * Allocated offset in @chunk on success, -1 if no matching area is
 479 * found.
 480 */
 481static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
 482{
 483        int oslot = pcpu_chunk_slot(chunk);
 484        int max_contig = 0;
 485        int i, off;
 486
 487        for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
 488                bool is_last = i + 1 == chunk->map_used;
 489                int head, tail;
 490
 491                /* extra for alignment requirement */
 492                head = ALIGN(off, align) - off;
 493                BUG_ON(i == 0 && head != 0);
 494
 495                if (chunk->map[i] < 0)
 496                        continue;
 497                if (chunk->map[i] < head + size) {
 498                        max_contig = max(chunk->map[i], max_contig);
 499                        continue;
 500                }
 501
 502                /*
 503                 * If head is small or the previous block is free,
 504                 * merge'em.  Note that 'small' is defined as smaller
 505                 * than sizeof(int), which is very small but isn't too
 506                 * uncommon for percpu allocations.
 507                 */
 508                if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
 509                        if (chunk->map[i - 1] > 0)
 510                                chunk->map[i - 1] += head;
 511                        else {
 512                                chunk->map[i - 1] -= head;
 513                                chunk->free_size -= head;
 514                        }
 515                        chunk->map[i] -= head;
 516                        off += head;
 517                        head = 0;
 518                }
 519
 520                /* if tail is small, just keep it around */
 521                tail = chunk->map[i] - head - size;
 522                if (tail < sizeof(int))
 523                        tail = 0;
 524
 525                /* split if warranted */
 526                if (head || tail) {
 527                        pcpu_split_block(chunk, i, head, tail);
 528                        if (head) {
 529                                i++;
 530                                off += head;
 531                                max_contig = max(chunk->map[i - 1], max_contig);
 532                        }
 533                        if (tail)
 534                                max_contig = max(chunk->map[i + 1], max_contig);
 535                }
 536
 537                /* update hint and mark allocated */
 538                if (is_last)
 539                        chunk->contig_hint = max_contig; /* fully scanned */
 540                else
 541                        chunk->contig_hint = max(chunk->contig_hint,
 542                                                 max_contig);
 543
 544                chunk->free_size -= chunk->map[i];
 545                chunk->map[i] = -chunk->map[i];
 546
 547                pcpu_chunk_relocate(chunk, oslot);
 548                return off;
 549        }
 550
 551        chunk->contig_hint = max_contig;        /* fully scanned */
 552        pcpu_chunk_relocate(chunk, oslot);
 553
 554        /* tell the upper layer that this chunk has no matching area */
 555        return -1;
 556}
 557
 558/**
 559 * pcpu_free_area - free area to a pcpu_chunk
 560 * @chunk: chunk of interest
 561 * @freeme: offset of area to free
 562 *
 563 * Free area starting from @freeme to @chunk.  Note that this function
 564 * only modifies the allocation map.  It doesn't depopulate or unmap
 565 * the area.
 566 *
 567 * CONTEXT:
 568 * pcpu_lock.
 569 */
 570static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
 571{
 572        int oslot = pcpu_chunk_slot(chunk);
 573        int i, off;
 574
 575        for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
 576                if (off == freeme)
 577                        break;
 578        BUG_ON(off != freeme);
 579        BUG_ON(chunk->map[i] > 0);
 580
 581        chunk->map[i] = -chunk->map[i];
 582        chunk->free_size += chunk->map[i];
 583
 584        /* merge with previous? */
 585        if (i > 0 && chunk->map[i - 1] >= 0) {
 586                chunk->map[i - 1] += chunk->map[i];
 587                chunk->map_used--;
 588                memmove(&chunk->map[i], &chunk->map[i + 1],
 589                        (chunk->map_used - i) * sizeof(chunk->map[0]));
 590                i--;
 591        }
 592        /* merge with next? */
 593        if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
 594                chunk->map[i] += chunk->map[i + 1];
 595                chunk->map_used--;
 596                memmove(&chunk->map[i + 1], &chunk->map[i + 2],
 597                        (chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
 598        }
 599
 600        chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
 601        pcpu_chunk_relocate(chunk, oslot);
 602}
 603
 604static struct pcpu_chunk *pcpu_alloc_chunk(void)
 605{
 606        struct pcpu_chunk *chunk;
 607
 608        chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size);
 609        if (!chunk)
 610                return NULL;
 611
 612        chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC *
 613                                                sizeof(chunk->map[0]));
 614        if (!chunk->map) {
 615                kfree(chunk);
 616                return NULL;
 617        }
 618
 619        chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
 620        chunk->map[chunk->map_used++] = pcpu_unit_size;
 621
 622        INIT_LIST_HEAD(&chunk->list);
 623        chunk->free_size = pcpu_unit_size;
 624        chunk->contig_hint = pcpu_unit_size;
 625
 626        return chunk;
 627}
 628
 629static void pcpu_free_chunk(struct pcpu_chunk *chunk)
 630{
 631        if (!chunk)
 632                return;
 633        pcpu_mem_free(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]));
 634        kfree(chunk);
 635}
 636
 637/*
 638 * Chunk management implementation.
 639 *
 640 * To allow different implementations, chunk alloc/free and
 641 * [de]population are implemented in a separate file which is pulled
 642 * into this file and compiled together.  The following functions
 643 * should be implemented.
 644 *
 645 * pcpu_populate_chunk          - populate the specified range of a chunk
 646 * pcpu_depopulate_chunk        - depopulate the specified range of a chunk
 647 * pcpu_create_chunk            - create a new chunk
 648 * pcpu_destroy_chunk           - destroy a chunk, always preceded by full depop
 649 * pcpu_addr_to_page            - translate address to physical address
 650 * pcpu_verify_alloc_info       - check alloc_info is acceptable during init
 651 */
 652static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size);
 653static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size);
 654static struct pcpu_chunk *pcpu_create_chunk(void);
 655static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
 656static struct page *pcpu_addr_to_page(void *addr);
 657static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
 658
 659#ifdef CONFIG_NEED_PER_CPU_KM
 660#include "percpu-km.c"
 661#else
 662#include "percpu-vm.c"
 663#endif
 664
 665/**
 666 * pcpu_chunk_addr_search - determine chunk containing specified address
 667 * @addr: address for which the chunk needs to be determined.
 668 *
 669 * RETURNS:
 670 * The address of the found chunk.
 671 */
 672static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
 673{
 674        /* is it in the first chunk? */
 675        if (pcpu_addr_in_first_chunk(addr)) {
 676                /* is it in the reserved area? */
 677                if (pcpu_addr_in_reserved_chunk(addr))
 678                        return pcpu_reserved_chunk;
 679                return pcpu_first_chunk;
 680        }
 681
 682        /*
 683         * The address is relative to unit0 which might be unused and
 684         * thus unmapped.  Offset the address to the unit space of the
 685         * current processor before looking it up in the vmalloc
 686         * space.  Note that any possible cpu id can be used here, so
 687         * there's no need to worry about preemption or cpu hotplug.
 688         */
 689        addr += pcpu_unit_offsets[raw_smp_processor_id()];
 690        return pcpu_get_page_chunk(pcpu_addr_to_page(addr));
 691}
 692
 693/**
 694 * pcpu_alloc - the percpu allocator
 695 * @size: size of area to allocate in bytes
 696 * @align: alignment of area (max PAGE_SIZE)
 697 * @reserved: allocate from the reserved chunk if available
 698 *
 699 * Allocate percpu area of @size bytes aligned at @align.
 700 *
 701 * CONTEXT:
 702 * Does GFP_KERNEL allocation.
 703 *
 704 * RETURNS:
 705 * Percpu pointer to the allocated area on success, NULL on failure.
 706 */
 707static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
 708{
 709        static int warn_limit = 10;
 710        struct pcpu_chunk *chunk;
 711        const char *err;
 712        int slot, off, new_alloc;
 713        unsigned long flags;
 714        void __percpu *ptr;
 715
 716        if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
 717                WARN(true, "illegal size (%zu) or align (%zu) for "
 718                     "percpu allocation\n", size, align);
 719                return NULL;
 720        }
 721
 722        mutex_lock(&pcpu_alloc_mutex);
 723        spin_lock_irqsave(&pcpu_lock, flags);
 724
 725        /* serve reserved allocations from the reserved chunk if available */
 726        if (reserved && pcpu_reserved_chunk) {
 727                chunk = pcpu_reserved_chunk;
 728
 729                if (size > chunk->contig_hint) {
 730                        err = "alloc from reserved chunk failed";
 731                        goto fail_unlock;
 732                }
 733
 734                while ((new_alloc = pcpu_need_to_extend(chunk))) {
 735                        spin_unlock_irqrestore(&pcpu_lock, flags);
 736                        if (pcpu_extend_area_map(chunk, new_alloc) < 0) {
 737                                err = "failed to extend area map of reserved chunk";
 738                                goto fail_unlock_mutex;
 739                        }
 740                        spin_lock_irqsave(&pcpu_lock, flags);
 741                }
 742
 743                off = pcpu_alloc_area(chunk, size, align);
 744                if (off >= 0)
 745                        goto area_found;
 746
 747                err = "alloc from reserved chunk failed";
 748                goto fail_unlock;
 749        }
 750
 751restart:
 752        /* search through normal chunks */
 753        for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
 754                list_for_each_entry(chunk, &pcpu_slot[slot], list) {
 755                        if (size > chunk->contig_hint)
 756                                continue;
 757
 758                        new_alloc = pcpu_need_to_extend(chunk);
 759                        if (new_alloc) {
 760                                spin_unlock_irqrestore(&pcpu_lock, flags);
 761                                if (pcpu_extend_area_map(chunk,
 762                                                         new_alloc) < 0) {
 763                                        err = "failed to extend area map";
 764                                        goto fail_unlock_mutex;
 765                                }
 766                                spin_lock_irqsave(&pcpu_lock, flags);
 767                                /*
 768                                 * pcpu_lock has been dropped, need to
 769                                 * restart cpu_slot list walking.
 770                                 */
 771                                goto restart;
 772                        }
 773
 774                        off = pcpu_alloc_area(chunk, size, align);
 775                        if (off >= 0)
 776                                goto area_found;
 777                }
 778        }
 779
 780        /* hmmm... no space left, create a new chunk */
 781        spin_unlock_irqrestore(&pcpu_lock, flags);
 782
 783        chunk = pcpu_create_chunk();
 784        if (!chunk) {
 785                err = "failed to allocate new chunk";
 786                goto fail_unlock_mutex;
 787        }
 788
 789        spin_lock_irqsave(&pcpu_lock, flags);
 790        pcpu_chunk_relocate(chunk, -1);
 791        goto restart;
 792
 793area_found:
 794        spin_unlock_irqrestore(&pcpu_lock, flags);
 795
 796        /* populate, map and clear the area */
 797        if (pcpu_populate_chunk(chunk, off, size)) {
 798                spin_lock_irqsave(&pcpu_lock, flags);
 799                pcpu_free_area(chunk, off);
 800                err = "failed to populate";
 801                goto fail_unlock;
 802        }
 803
 804        mutex_unlock(&pcpu_alloc_mutex);
 805
 806        /* return address relative to base address */
 807        ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
 808        kmemleak_alloc_percpu(ptr, size);
 809        return ptr;
 810
 811fail_unlock:
 812        spin_unlock_irqrestore(&pcpu_lock, flags);
 813fail_unlock_mutex:
 814        mutex_unlock(&pcpu_alloc_mutex);
 815        if (warn_limit) {
 816                pr_warning("PERCPU: allocation failed, size=%zu align=%zu, "
 817                           "%s\n", size, align, err);
 818                dump_stack();
 819                if (!--warn_limit)
 820                        pr_info("PERCPU: limit reached, disable warning\n");
 821        }
 822        return NULL;
 823}
 824
 825/**
 826 * __alloc_percpu - allocate dynamic percpu area
 827 * @size: size of area to allocate in bytes
 828 * @align: alignment of area (max PAGE_SIZE)
 829 *
 830 * Allocate zero-filled percpu area of @size bytes aligned at @align.
 831 * Might sleep.  Might trigger writeouts.
 832 *
 833 * CONTEXT:
 834 * Does GFP_KERNEL allocation.
 835 *
 836 * RETURNS:
 837 * Percpu pointer to the allocated area on success, NULL on failure.
 838 */
 839void __percpu *__alloc_percpu(size_t size, size_t align)
 840{
 841        return pcpu_alloc(size, align, false);
 842}
 843EXPORT_SYMBOL_GPL(__alloc_percpu);
 844
 845/**
 846 * __alloc_reserved_percpu - allocate reserved percpu area
 847 * @size: size of area to allocate in bytes
 848 * @align: alignment of area (max PAGE_SIZE)
 849 *
 850 * Allocate zero-filled percpu area of @size bytes aligned at @align
 851 * from reserved percpu area if arch has set it up; otherwise,
 852 * allocation is served from the same dynamic area.  Might sleep.
 853 * Might trigger writeouts.
 854 *
 855 * CONTEXT:
 856 * Does GFP_KERNEL allocation.
 857 *
 858 * RETURNS:
 859 * Percpu pointer to the allocated area on success, NULL on failure.
 860 */
 861void __percpu *__alloc_reserved_percpu(size_t size, size_t align)
 862{
 863        return pcpu_alloc(size, align, true);
 864}
 865
 866/**
 867 * pcpu_reclaim - reclaim fully free chunks, workqueue function
 868 * @work: unused
 869 *
 870 * Reclaim all fully free chunks except for the first one.
 871 *
 872 * CONTEXT:
 873 * workqueue context.
 874 */
 875static void pcpu_reclaim(struct work_struct *work)
 876{
 877        LIST_HEAD(todo);
 878        struct list_head *head = &pcpu_slot[pcpu_nr_slots - 1];
 879        struct pcpu_chunk *chunk, *next;
 880
 881        mutex_lock(&pcpu_alloc_mutex);
 882        spin_lock_irq(&pcpu_lock);
 883
 884        list_for_each_entry_safe(chunk, next, head, list) {
 885                WARN_ON(chunk->immutable);
 886
 887                /* spare the first one */
 888                if (chunk == list_first_entry(head, struct pcpu_chunk, list))
 889                        continue;
 890
 891                list_move(&chunk->list, &todo);
 892        }
 893
 894        spin_unlock_irq(&pcpu_lock);
 895
 896        list_for_each_entry_safe(chunk, next, &todo, list) {
 897                pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
 898                pcpu_destroy_chunk(chunk);
 899        }
 900
 901        mutex_unlock(&pcpu_alloc_mutex);
 902}
 903
 904/**
 905 * free_percpu - free percpu area
 906 * @ptr: pointer to area to free
 907 *
 908 * Free percpu area @ptr.
 909 *
 910 * CONTEXT:
 911 * Can be called from atomic context.
 912 */
 913void free_percpu(void __percpu *ptr)
 914{
 915        void *addr;
 916        struct pcpu_chunk *chunk;
 917        unsigned long flags;
 918        int off;
 919
 920        if (!ptr)
 921                return;
 922
 923        kmemleak_free_percpu(ptr);
 924
 925        addr = __pcpu_ptr_to_addr(ptr);
 926
 927        spin_lock_irqsave(&pcpu_lock, flags);
 928
 929        chunk = pcpu_chunk_addr_search(addr);
 930        off = addr - chunk->base_addr;
 931
 932        pcpu_free_area(chunk, off);
 933
 934        /* if there are more than one fully free chunks, wake up grim reaper */
 935        if (chunk->free_size == pcpu_unit_size) {
 936                struct pcpu_chunk *pos;
 937
 938                list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
 939                        if (pos != chunk) {
 940                                schedule_work(&pcpu_reclaim_work);
 941                                break;
 942                        }
 943        }
 944
 945        spin_unlock_irqrestore(&pcpu_lock, flags);
 946}
 947EXPORT_SYMBOL_GPL(free_percpu);
 948
 949/**
 950 * is_kernel_percpu_address - test whether address is from static percpu area
 951 * @addr: address to test
 952 *
 953 * Test whether @addr belongs to in-kernel static percpu area.  Module
 954 * static percpu areas are not considered.  For those, use
 955 * is_module_percpu_address().
 956 *
 957 * RETURNS:
 958 * %true if @addr is from in-kernel static percpu area, %false otherwise.
 959 */
 960bool is_kernel_percpu_address(unsigned long addr)
 961{
 962#ifdef CONFIG_SMP
 963        const size_t static_size = __per_cpu_end - __per_cpu_start;
 964        void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
 965        unsigned int cpu;
 966
 967        for_each_possible_cpu(cpu) {
 968                void *start = per_cpu_ptr(base, cpu);
 969
 970                if ((void *)addr >= start && (void *)addr < start + static_size)
 971                        return true;
 972        }
 973#endif
 974        /* on UP, can't distinguish from other static vars, always false */
 975        return false;
 976}
 977
 978/**
 979 * per_cpu_ptr_to_phys - convert translated percpu address to physical address
 980 * @addr: the address to be converted to physical address
 981 *
 982 * Given @addr which is dereferenceable address obtained via one of
 983 * percpu access macros, this function translates it into its physical
 984 * address.  The caller is responsible for ensuring @addr stays valid
 985 * until this function finishes.
 986 *
 987 * percpu allocator has special setup for the first chunk, which currently
 988 * supports either embedding in linear address space or vmalloc mapping,
 989 * and, from the second one, the backing allocator (currently either vm or
 990 * km) provides translation.
 991 *
 992 * The addr can be tranlated simply without checking if it falls into the
 993 * first chunk. But the current code reflects better how percpu allocator
 994 * actually works, and the verification can discover both bugs in percpu
 995 * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
 996 * code.
 997 *
 998 * RETURNS:
 999 * The physical address for @addr.
1000 */
1001phys_addr_t per_cpu_ptr_to_phys(void *addr)
1002{
1003        void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
1004        bool in_first_chunk = false;
1005        unsigned long first_low, first_high;
1006        unsigned int cpu;
1007
1008        /*
1009         * The following test on unit_low/high isn't strictly
1010         * necessary but will speed up lookups of addresses which
1011         * aren't in the first chunk.
1012         */
1013        first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
1014        first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
1015                                     pcpu_unit_pages);
1016        if ((unsigned long)addr >= first_low &&
1017            (unsigned long)addr < first_high) {
1018                for_each_possible_cpu(cpu) {
1019                        void *start = per_cpu_ptr(base, cpu);
1020
1021                        if (addr >= start && addr < start + pcpu_unit_size) {
1022                                in_first_chunk = true;
1023                                break;
1024                        }
1025                }
1026        }
1027
1028        if (in_first_chunk) {
1029                if (!is_vmalloc_addr(addr))
1030                        return __pa(addr);
1031                else
1032                        return page_to_phys(vmalloc_to_page(addr)) +
1033                               offset_in_page(addr);
1034        } else
1035                return page_to_phys(pcpu_addr_to_page(addr)) +
1036                       offset_in_page(addr);
1037}
1038
1039/**
1040 * pcpu_alloc_alloc_info - allocate percpu allocation info
1041 * @nr_groups: the number of groups
1042 * @nr_units: the number of units
1043 *
1044 * Allocate ai which is large enough for @nr_groups groups containing
1045 * @nr_units units.  The returned ai's groups[0].cpu_map points to the
1046 * cpu_map array which is long enough for @nr_units and filled with
1047 * NR_CPUS.  It's the caller's responsibility to initialize cpu_map
1048 * pointer of other groups.
1049 *
1050 * RETURNS:
1051 * Pointer to the allocated pcpu_alloc_info on success, NULL on
1052 * failure.
1053 */
1054struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
1055                                                      int nr_units)
1056{
1057        struct pcpu_alloc_info *ai;
1058        size_t base_size, ai_size;
1059        void *ptr;
1060        int unit;
1061
1062        base_size = ALIGN(sizeof(*ai) + nr_groups * sizeof(ai->groups[0]),
1063                          __alignof__(ai->groups[0].cpu_map[0]));
1064        ai_size = base_size + nr_units * sizeof(ai->groups[0].cpu_map[0]);
1065
1066        ptr = alloc_bootmem_nopanic(PFN_ALIGN(ai_size));
1067        if (!ptr)
1068                return NULL;
1069        ai = ptr;
1070        ptr += base_size;
1071
1072        ai->groups[0].cpu_map = ptr;
1073
1074        for (unit = 0; unit < nr_units; unit++)
1075                ai->groups[0].cpu_map[unit] = NR_CPUS;
1076
1077        ai->nr_groups = nr_groups;
1078        ai->__ai_size = PFN_ALIGN(ai_size);
1079
1080        return ai;
1081}
1082
1083/**
1084 * pcpu_free_alloc_info - free percpu allocation info
1085 * @ai: pcpu_alloc_info to free
1086 *
1087 * Free @ai which was allocated by pcpu_alloc_alloc_info().
1088 */
1089void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai)
1090{
1091        free_bootmem(__pa(ai), ai->__ai_size);
1092}
1093
1094/**
1095 * pcpu_dump_alloc_info - print out information about pcpu_alloc_info
1096 * @lvl: loglevel
1097 * @ai: allocation info to dump
1098 *
1099 * Print out information about @ai using loglevel @lvl.
1100 */
1101static void pcpu_dump_alloc_info(const char *lvl,
1102                                 const struct pcpu_alloc_info *ai)
1103{
1104        int group_width = 1, cpu_width = 1, width;
1105        char empty_str[] = "--------";
1106        int alloc = 0, alloc_end = 0;
1107        int group, v;
1108        int upa, apl;   /* units per alloc, allocs per line */
1109
1110        v = ai->nr_groups;
1111        while (v /= 10)
1112                group_width++;
1113
1114        v = num_possible_cpus();
1115        while (v /= 10)
1116                cpu_width++;
1117        empty_str[min_t(int, cpu_width, sizeof(empty_str) - 1)] = '\0';
1118
1119        upa = ai->alloc_size / ai->unit_size;
1120        width = upa * (cpu_width + 1) + group_width + 3;
1121        apl = rounddown_pow_of_two(max(60 / width, 1));
1122
1123        printk("%spcpu-alloc: s%zu r%zu d%zu u%zu alloc=%zu*%zu",
1124               lvl, ai->static_size, ai->reserved_size, ai->dyn_size,
1125               ai->unit_size, ai->alloc_size / ai->atom_size, ai->atom_size);
1126
1127        for (group = 0; group < ai->nr_groups; group++) {
1128                const struct pcpu_group_info *gi = &ai->groups[group];
1129                int unit = 0, unit_end = 0;
1130
1131                BUG_ON(gi->nr_units % upa);
1132                for (alloc_end += gi->nr_units / upa;
1133                     alloc < alloc_end; alloc++) {
1134                        if (!(alloc % apl)) {
1135                                printk(KERN_CONT "\n");
1136                                printk("%spcpu-alloc: ", lvl);
1137                        }
1138                        printk(KERN_CONT "[%0*d] ", group_width, group);
1139
1140                        for (unit_end += upa; unit < unit_end; unit++)
1141                                if (gi->cpu_map[unit] != NR_CPUS)
1142                                        printk(KERN_CONT "%0*d ", cpu_width,
1143                                               gi->cpu_map[unit]);
1144                                else
1145                                        printk(KERN_CONT "%s ", empty_str);
1146                }
1147        }
1148        printk(KERN_CONT "\n");
1149}
1150
1151/**
1152 * pcpu_setup_first_chunk - initialize the first percpu chunk
1153 * @ai: pcpu_alloc_info describing how to percpu area is shaped
1154 * @base_addr: mapped address
1155 *
1156 * Initialize the first percpu chunk which contains the kernel static
1157 * perpcu area.  This function is to be called from arch percpu area
1158 * setup path.
1159 *
1160 * @ai contains all information necessary to initialize the first
1161 * chunk and prime the dynamic percpu allocator.
1162 *
1163 * @ai->static_size is the size of static percpu area.
1164 *
1165 * @ai->reserved_size, if non-zero, specifies the amount of bytes to
1166 * reserve after the static area in the first chunk.  This reserves
1167 * the first chunk such that it's available only through reserved
1168 * percpu allocation.  This is primarily used to serve module percpu
1169 * static areas on architectures where the addressing model has
1170 * limited offset range for symbol relocations to guarantee module
1171 * percpu symbols fall inside the relocatable range.
1172 *
1173 * @ai->dyn_size determines the number of bytes available for dynamic
1174 * allocation in the first chunk.  The area between @ai->static_size +
1175 * @ai->reserved_size + @ai->dyn_size and @ai->unit_size is unused.
1176 *
1177 * @ai->unit_size specifies unit size and must be aligned to PAGE_SIZE
1178 * and equal to or larger than @ai->static_size + @ai->reserved_size +
1179 * @ai->dyn_size.
1180 *
1181 * @ai->atom_size is the allocation atom size and used as alignment
1182 * for vm areas.
1183 *
1184 * @ai->alloc_size is the allocation size and always multiple of
1185 * @ai->atom_size.  This is larger than @ai->atom_size if
1186 * @ai->unit_size is larger than @ai->atom_size.
1187 *
1188 * @ai->nr_groups and @ai->groups describe virtual memory layout of
1189 * percpu areas.  Units which should be colocated are put into the
1190 * same group.  Dynamic VM areas will be allocated according to these
1191 * groupings.  If @ai->nr_groups is zero, a single group containing
1192 * all units is assumed.
1193 *
1194 * The caller should have mapped the first chunk at @base_addr and
1195 * copied static data to each unit.
1196 *
1197 * If the first chunk ends up with both reserved and dynamic areas, it
1198 * is served by two chunks - one to serve the core static and reserved
1199 * areas and the other for the dynamic area.  They share the same vm
1200 * and page map but uses different area allocation map to stay away
1201 * from each other.  The latter chunk is circulated in the chunk slots
1202 * and available for dynamic allocation like any other chunks.
1203 *
1204 * RETURNS:
1205 * 0 on success, -errno on failure.
1206 */
1207int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
1208                                  void *base_addr)
1209{
1210        static char cpus_buf[4096] __initdata;
1211        static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1212        static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata;
1213        size_t dyn_size = ai->dyn_size;
1214        size_t size_sum = ai->static_size + ai->reserved_size + dyn_size;
1215        struct pcpu_chunk *schunk, *dchunk = NULL;
1216        unsigned long *group_offsets;
1217        size_t *group_sizes;
1218        unsigned long *unit_off;
1219        unsigned int cpu;
1220        int *unit_map;
1221        int group, unit, i;
1222
1223        cpumask_scnprintf(cpus_buf, sizeof(cpus_buf), cpu_possible_mask);
1224
1225#define PCPU_SETUP_BUG_ON(cond) do {                                    \
1226        if (unlikely(cond)) {                                           \
1227                pr_emerg("PERCPU: failed to initialize, %s", #cond);    \
1228                pr_emerg("PERCPU: cpu_possible_mask=%s\n", cpus_buf);   \
1229                pcpu_dump_alloc_info(KERN_EMERG, ai);                   \
1230                BUG();                                                  \
1231        }                                                               \
1232} while (0)
1233
1234        /* sanity checks */
1235        PCPU_SETUP_BUG_ON(ai->nr_groups <= 0);
1236#ifdef CONFIG_SMP
1237        PCPU_SETUP_BUG_ON(!ai->static_size);
1238        PCPU_SETUP_BUG_ON((unsigned long)__per_cpu_start & ~PAGE_MASK);
1239#endif
1240        PCPU_SETUP_BUG_ON(!base_addr);
1241        PCPU_SETUP_BUG_ON((unsigned long)base_addr & ~PAGE_MASK);
1242        PCPU_SETUP_BUG_ON(ai->unit_size < size_sum);
1243        PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK);
1244        PCPU_SETUP_BUG_ON(ai->unit_size < PCPU_MIN_UNIT_SIZE);
1245        PCPU_SETUP_BUG_ON(ai->dyn_size < PERCPU_DYNAMIC_EARLY_SIZE);
1246        PCPU_SETUP_BUG_ON(pcpu_verify_alloc_info(ai) < 0);
1247
1248        /* process group information and build config tables accordingly */
1249        group_offsets = alloc_bootmem(ai->nr_groups * sizeof(group_offsets[0]));
1250        group_sizes = alloc_bootmem(ai->nr_groups * sizeof(group_sizes[0]));
1251        unit_map = alloc_bootmem(nr_cpu_ids * sizeof(unit_map[0]));
1252        unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
1253
1254        for (cpu = 0; cpu < nr_cpu_ids; cpu++)
1255                unit_map[cpu] = UINT_MAX;
1256
1257        pcpu_low_unit_cpu = NR_CPUS;
1258        pcpu_high_unit_cpu = NR_CPUS;
1259
1260        for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
1261                const struct pcpu_group_info *gi = &ai->groups[group];
1262
1263                group_offsets[group] = gi->base_offset;
1264                group_sizes[group] = gi->nr_units * ai->unit_size;
1265
1266                for (i = 0; i < gi->nr_units; i++) {
1267                        cpu = gi->cpu_map[i];
1268                        if (cpu == NR_CPUS)
1269                                continue;
1270
1271                        PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
1272                        PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
1273                        PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);
1274
1275                        unit_map[cpu] = unit + i;
1276                        unit_off[cpu] = gi->base_offset + i * ai->unit_size;
1277
1278                        /* determine low/high unit_cpu */
1279                        if (pcpu_low_unit_cpu == NR_CPUS ||
1280                            unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
1281                                pcpu_low_unit_cpu = cpu;
1282                        if (pcpu_high_unit_cpu == NR_CPUS ||
1283                            unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
1284                                pcpu_high_unit_cpu = cpu;
1285                }
1286        }
1287        pcpu_nr_units = unit;
1288
1289        for_each_possible_cpu(cpu)
1290                PCPU_SETUP_BUG_ON(unit_map[cpu] == UINT_MAX);
1291
1292        /* we're done parsing the input, undefine BUG macro and dump config */
1293#undef PCPU_SETUP_BUG_ON
1294        pcpu_dump_alloc_info(KERN_DEBUG, ai);
1295
1296        pcpu_nr_groups = ai->nr_groups;
1297        pcpu_group_offsets = group_offsets;
1298        pcpu_group_sizes = group_sizes;
1299        pcpu_unit_map = unit_map;
1300        pcpu_unit_offsets = unit_off;
1301
1302        /* determine basic parameters */
1303        pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
1304        pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
1305        pcpu_atom_size = ai->atom_size;
1306        pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
1307                BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
1308
1309        /*
1310         * Allocate chunk slots.  The additional last slot is for
1311         * empty chunks.
1312         */
1313        pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
1314        pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
1315        for (i = 0; i < pcpu_nr_slots; i++)
1316                INIT_LIST_HEAD(&pcpu_slot[i]);
1317
1318        /*
1319         * Initialize static chunk.  If reserved_size is zero, the
1320         * static chunk covers static area + dynamic allocation area
1321         * in the first chunk.  If reserved_size is not zero, it
1322         * covers static area + reserved area (mostly used for module
1323         * static percpu allocation).
1324         */
1325        schunk = alloc_bootmem(pcpu_chunk_struct_size);
1326        INIT_LIST_HEAD(&schunk->list);
1327        schunk->base_addr = base_addr;
1328        schunk->map = smap;
1329        schunk->map_alloc = ARRAY_SIZE(smap);
1330        schunk->immutable = true;
1331        bitmap_fill(schunk->populated, pcpu_unit_pages);
1332
1333        if (ai->reserved_size) {
1334                schunk->free_size = ai->reserved_size;
1335                pcpu_reserved_chunk = schunk;
1336                pcpu_reserved_chunk_limit = ai->static_size + ai->reserved_size;
1337        } else {
1338                schunk->free_size = dyn_size;
1339                dyn_size = 0;                   /* dynamic area covered */
1340        }
1341        schunk->contig_hint = schunk->free_size;
1342
1343        schunk->map[schunk->map_used++] = -ai->static_size;
1344        if (schunk->free_size)
1345                schunk->map[schunk->map_used++] = schunk->free_size;
1346
1347        /* init dynamic chunk if necessary */
1348        if (dyn_size) {
1349                dchunk = alloc_bootmem(pcpu_chunk_struct_size);
1350                INIT_LIST_HEAD(&dchunk->list);
1351                dchunk->base_addr = base_addr;
1352                dchunk->map = dmap;
1353                dchunk->map_alloc = ARRAY_SIZE(dmap);
1354                dchunk->immutable = true;
1355                bitmap_fill(dchunk->populated, pcpu_unit_pages);
1356
1357                dchunk->contig_hint = dchunk->free_size = dyn_size;
1358                dchunk->map[dchunk->map_used++] = -pcpu_reserved_chunk_limit;
1359                dchunk->map[dchunk->map_used++] = dchunk->free_size;
1360        }
1361
1362        /* link the first chunk in */
1363        pcpu_first_chunk = dchunk ?: schunk;
1364        pcpu_chunk_relocate(pcpu_first_chunk, -1);
1365
1366        /* we're done */
1367        pcpu_base_addr = base_addr;
1368        return 0;
1369}
1370
1371#ifdef CONFIG_SMP
1372
1373const char * const pcpu_fc_names[PCPU_FC_NR] __initconst = {
1374        [PCPU_FC_AUTO]  = "auto",
1375        [PCPU_FC_EMBED] = "embed",
1376        [PCPU_FC_PAGE]  = "page",
1377};
1378
1379enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
1380
1381static int __init percpu_alloc_setup(char *str)
1382{
1383        if (0)
1384                /* nada */;
1385#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
1386        else if (!strcmp(str, "embed"))
1387                pcpu_chosen_fc = PCPU_FC_EMBED;
1388#endif
1389#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1390        else if (!strcmp(str, "page"))
1391                pcpu_chosen_fc = PCPU_FC_PAGE;
1392#endif
1393        else
1394                pr_warning("PERCPU: unknown allocator %s specified\n", str);
1395
1396        return 0;
1397}
1398early_param("percpu_alloc", percpu_alloc_setup);
1399
1400/*
1401 * pcpu_embed_first_chunk() is used by the generic percpu setup.
1402 * Build it if needed by the arch config or the generic setup is going
1403 * to be used.
1404 */
1405#if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \
1406        !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
1407#define BUILD_EMBED_FIRST_CHUNK
1408#endif
1409
1410/* build pcpu_page_first_chunk() iff needed by the arch config */
1411#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
1412#define BUILD_PAGE_FIRST_CHUNK
1413#endif
1414
1415/* pcpu_build_alloc_info() is used by both embed and page first chunk */
1416#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK)
1417/**
1418 * pcpu_build_alloc_info - build alloc_info considering distances between CPUs
1419 * @reserved_size: the size of reserved percpu area in bytes
1420 * @dyn_size: minimum free size for dynamic allocation in bytes
1421 * @atom_size: allocation atom size
1422 * @cpu_distance_fn: callback to determine distance between cpus, optional
1423 *
1424 * This function determines grouping of units, their mappings to cpus
1425 * and other parameters considering needed percpu size, allocation
1426 * atom size and distances between CPUs.
1427 *
1428 * Groups are always mutliples of atom size and CPUs which are of
1429 * LOCAL_DISTANCE both ways are grouped together and share space for
1430 * units in the same group.  The returned configuration is guaranteed
1431 * to have CPUs on different nodes on different groups and >=75% usage
1432 * of allocated virtual address space.
1433 *
1434 * RETURNS:
1435 * On success, pointer to the new allocation_info is returned.  On
1436 * failure, ERR_PTR value is returned.
1437 */
1438static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
1439                                size_t reserved_size, size_t dyn_size,
1440                                size_t atom_size,
1441                                pcpu_fc_cpu_distance_fn_t cpu_distance_fn)
1442{
1443        static int group_map[NR_CPUS] __initdata;
1444        static int group_cnt[NR_CPUS] __initdata;
1445        const size_t static_size = __per_cpu_end - __per_cpu_start;
1446        int nr_groups = 1, nr_units = 0;
1447        size_t size_sum, min_unit_size, alloc_size;
1448        int upa, max_upa, uninitialized_var(best_upa);  /* units_per_alloc */
1449        int last_allocs, group, unit;
1450        unsigned int cpu, tcpu;
1451        struct pcpu_alloc_info *ai;
1452        unsigned int *cpu_map;
1453
1454        /* this function may be called multiple times */
1455        memset(group_map, 0, sizeof(group_map));
1456        memset(group_cnt, 0, sizeof(group_cnt));
1457
1458        /* calculate size_sum and ensure dyn_size is enough for early alloc */
1459        size_sum = PFN_ALIGN(static_size + reserved_size +
1460                            max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE));
1461        dyn_size = size_sum - static_size - reserved_size;
1462
1463        /*
1464         * Determine min_unit_size, alloc_size and max_upa such that
1465         * alloc_size is multiple of atom_size and is the smallest
1466         * which can accommodate 4k aligned segments which are equal to
1467         * or larger than min_unit_size.
1468         */
1469        min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE);
1470
1471        alloc_size = roundup(min_unit_size, atom_size);
1472        upa = alloc_size / min_unit_size;
1473        while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1474                upa--;
1475        max_upa = upa;
1476
1477        /* group cpus according to their proximity */
1478        for_each_possible_cpu(cpu) {
1479                group = 0;
1480        next_group:
1481                for_each_possible_cpu(tcpu) {
1482                        if (cpu == tcpu)
1483                                break;
1484                        if (group_map[tcpu] == group && cpu_distance_fn &&
1485                            (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE ||
1486                             cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) {
1487                                group++;
1488                                nr_groups = max(nr_groups, group + 1);
1489                                goto next_group;
1490                        }
1491                }
1492                group_map[cpu] = group;
1493                group_cnt[group]++;
1494        }
1495
1496        /*
1497         * Expand unit size until address space usage goes over 75%
1498         * and then as much as possible without using more address
1499         * space.
1500         */
1501        last_allocs = INT_MAX;
1502        for (upa = max_upa; upa; upa--) {
1503                int allocs = 0, wasted = 0;
1504
1505                if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK))
1506                        continue;
1507
1508                for (group = 0; group < nr_groups; group++) {
1509                        int this_allocs = DIV_ROUND_UP(group_cnt[group], upa);
1510                        allocs += this_allocs;
1511                        wasted += this_allocs * upa - group_cnt[group];
1512                }
1513
1514                /*
1515                 * Don't accept if wastage is over 1/3.  The
1516                 * greater-than comparison ensures upa==1 always
1517                 * passes the following check.
1518                 */
1519                if (wasted > num_possible_cpus() / 3)
1520                        continue;
1521
1522                /* and then don't consume more memory */
1523                if (allocs > last_allocs)
1524                        break;
1525                last_allocs = allocs;
1526                best_upa = upa;
1527        }
1528        upa = best_upa;
1529
1530        /* allocate and fill alloc_info */
1531        for (group = 0; group < nr_groups; group++)
1532                nr_units += roundup(group_cnt[group], upa);
1533
1534        ai = pcpu_alloc_alloc_info(nr_groups, nr_units);
1535        if (!ai)
1536                return ERR_PTR(-ENOMEM);
1537        cpu_map = ai->groups[0].cpu_map;
1538
1539        for (group = 0; group < nr_groups; group++) {
1540                ai->groups[group].cpu_map = cpu_map;
1541                cpu_map += roundup(group_cnt[group], upa);
1542        }
1543
1544        ai->static_size = static_size;
1545        ai->reserved_size = reserved_size;
1546        ai->dyn_size = dyn_size;
1547        ai->unit_size = alloc_size / upa;
1548        ai->atom_size = atom_size;
1549        ai->alloc_size = alloc_size;
1550
1551        for (group = 0, unit = 0; group_cnt[group]; group++) {
1552                struct pcpu_group_info *gi = &ai->groups[group];
1553
1554                /*
1555                 * Initialize base_offset as if all groups are located
1556                 * back-to-back.  The caller should update this to
1557                 * reflect actual allocation.
1558                 */
1559                gi->base_offset = unit * ai->unit_size;
1560
1561                for_each_possible_cpu(cpu)
1562                        if (group_map[cpu] == group)
1563                                gi->cpu_map[gi->nr_units++] = cpu;
1564                gi->nr_units = roundup(gi->nr_units, upa);
1565                unit += gi->nr_units;
1566        }
1567        BUG_ON(unit != nr_units);
1568
1569        return ai;
1570}
1571#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */
1572
1573#if defined(BUILD_EMBED_FIRST_CHUNK)
1574/**
1575 * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem
1576 * @reserved_size: the size of reserved percpu area in bytes
1577 * @dyn_size: minimum free size for dynamic allocation in bytes
1578 * @atom_size: allocation atom size
1579 * @cpu_distance_fn: callback to determine distance between cpus, optional
1580 * @alloc_fn: function to allocate percpu page
1581 * @free_fn: function to free percpu page
1582 *
1583 * This is a helper to ease setting up embedded first percpu chunk and
1584 * can be called where pcpu_setup_first_chunk() is expected.
1585 *
1586 * If this function is used to setup the first chunk, it is allocated
1587 * by calling @alloc_fn and used as-is without being mapped into
1588 * vmalloc area.  Allocations are always whole multiples of @atom_size
1589 * aligned to @atom_size.
1590 *
1591 * This enables the first chunk to piggy back on the linear physical
1592 * mapping which often uses larger page size.  Please note that this
1593 * can result in very sparse cpu->unit mapping on NUMA machines thus
1594 * requiring large vmalloc address space.  Don't use this allocator if
1595 * vmalloc space is not orders of magnitude larger than distances
1596 * between node memory addresses (ie. 32bit NUMA machines).
1597 *
1598 * @dyn_size specifies the minimum dynamic area size.
1599 *
1600 * If the needed size is smaller than the minimum or specified unit
1601 * size, the leftover is returned using @free_fn.
1602 *
1603 * RETURNS:
1604 * 0 on success, -errno on failure.
1605 */
1606int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
1607                                  size_t atom_size,
1608                                  pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
1609                                  pcpu_fc_alloc_fn_t alloc_fn,
1610                                  pcpu_fc_free_fn_t free_fn)
1611{
1612        void *base = (void *)ULONG_MAX;
1613        void **areas = NULL;
1614        struct pcpu_alloc_info *ai;
1615        size_t size_sum, areas_size, max_distance;
1616        int group, i, rc;
1617
1618        ai = pcpu_build_alloc_info(reserved_size, dyn_size, atom_size,
1619                                   cpu_distance_fn);
1620        if (IS_ERR(ai))
1621                return PTR_ERR(ai);
1622
1623        size_sum = ai->static_size + ai->reserved_size + ai->dyn_size;
1624        areas_size = PFN_ALIGN(ai->nr_groups * sizeof(void *));
1625
1626        areas = alloc_bootmem_nopanic(areas_size);
1627        if (!areas) {
1628                rc = -ENOMEM;
1629                goto out_free;
1630        }
1631
1632        /* allocate, copy and determine base address */
1633        for (group = 0; group < ai->nr_groups; group++) {
1634                struct pcpu_group_info *gi = &ai->groups[group];
1635                unsigned int cpu = NR_CPUS;
1636                void *ptr;
1637
1638                for (i = 0; i < gi->nr_units && cpu == NR_CPUS; i++)
1639                        cpu = gi->cpu_map[i];
1640                BUG_ON(cpu == NR_CPUS);
1641
1642                /* allocate space for the whole group */
1643                ptr = alloc_fn(cpu, gi->nr_units * ai->unit_size, atom_size);
1644                if (!ptr) {
1645                        rc = -ENOMEM;
1646                        goto out_free_areas;
1647                }
1648                /* kmemleak tracks the percpu allocations separately */
1649                kmemleak_free(ptr);
1650                areas[group] = ptr;
1651
1652                base = min(ptr, base);
1653        }
1654
1655        /*
1656         * Copy data and free unused parts.  This should happen after all
1657         * allocations are complete; otherwise, we may end up with
1658         * overlapping groups.
1659         */
1660        for (group = 0; group < ai->nr_groups; group++) {
1661                struct pcpu_group_info *gi = &ai->groups[group];
1662                void *ptr = areas[group];
1663
1664                for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) {
1665                        if (gi->cpu_map[i] == NR_CPUS) {
1666                                /* unused unit, free whole */
1667                                free_fn(ptr, ai->unit_size);
1668                                continue;
1669                        }
1670                        /* copy and return the unused part */
1671                        memcpy(ptr, __per_cpu_load, ai->static_size);
1672                        free_fn(ptr + size_sum, ai->unit_size - size_sum);
1673                }
1674        }
1675
1676        /* base address is now known, determine group base offsets */
1677        max_distance = 0;
1678        for (group = 0; group < ai->nr_groups; group++) {
1679                ai->groups[group].base_offset = areas[group] - base;
1680                max_distance = max_t(size_t, max_distance,
1681                                     ai->groups[group].base_offset);
1682        }
1683        max_distance += ai->unit_size;
1684
1685        /* warn if maximum distance is further than 75% of vmalloc space */
1686        if (max_distance > (VMALLOC_END - VMALLOC_START) * 3 / 4) {
1687                pr_warning("PERCPU: max_distance=0x%zx too large for vmalloc "
1688                           "space 0x%lx\n", max_distance,
1689                           (unsigned long)(VMALLOC_END - VMALLOC_START));
1690#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
1691                /* and fail if we have fallback */
1692                rc = -EINVAL;
1693                goto out_free;
1694#endif
1695        }
1696
1697        pr_info("PERCPU: Embedded %zu pages/cpu @%p s%zu r%zu d%zu u%zu\n",
1698                PFN_DOWN(size_sum), base, ai->static_size, ai->reserved_size,
1699                ai->dyn_size, ai->unit_size);
1700
1701        rc = pcpu_setup_first_chunk(ai, base);
1702        goto out_free;
1703
1704out_free_areas:
1705        for (group = 0; group < ai->nr_groups; group++)
1706                free_fn(areas[group],
1707                        ai->groups[group].nr_units * ai->unit_size);
1708out_free:
1709        pcpu_free_alloc_info(ai);
1710        if (areas)
1711                free_bootmem(__pa(areas), areas_size);
1712        return rc;
1713}
1714#endif /* BUILD_EMBED_FIRST_CHUNK */
1715
1716#ifdef BUILD_PAGE_FIRST_CHUNK
1717/**
1718 * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages
1719 * @reserved_size: the size of reserved percpu area in bytes
1720 * @alloc_fn: function to allocate percpu page, always called with PAGE_SIZE
1721 * @free_fn: function to free percpu page, always called with PAGE_SIZE
1722 * @populate_pte_fn: function to populate pte
1723 *
1724 * This is a helper to ease setting up page-remapped first percpu
1725 * chunk and can be called where pcpu_setup_first_chunk() is expected.
1726 *
1727 * This is the basic allocator.  Static percpu area is allocated
1728 * page-by-page into vmalloc area.
1729 *
1730 * RETURNS:
1731 * 0 on success, -errno on failure.
1732 */
1733int __init pcpu_page_first_chunk(size_t reserved_size,
1734                                 pcpu_fc_alloc_fn_t alloc_fn,
1735                                 pcpu_fc_free_fn_t free_fn,
1736                                 pcpu_fc_populate_pte_fn_t populate_pte_fn)
1737{
1738        static struct vm_struct vm;
1739        struct pcpu_alloc_info *ai;
1740        char psize_str[16];
1741        int unit_pages;
1742        size_t pages_size;
1743        struct page **pages;
1744        int unit, i, j, rc;
1745
1746        snprintf(psize_str, sizeof(psize_str), "%luK", PAGE_SIZE >> 10);
1747
1748        ai = pcpu_build_alloc_info(reserved_size, 0, PAGE_SIZE, NULL);
1749        if (IS_ERR(ai))
1750                return PTR_ERR(ai);
1751        BUG_ON(ai->nr_groups != 1);
1752        BUG_ON(ai->groups[0].nr_units != num_possible_cpus());
1753
1754        unit_pages = ai->unit_size >> PAGE_SHIFT;
1755
1756        /* unaligned allocations can't be freed, round up to page size */
1757        pages_size = PFN_ALIGN(unit_pages * num_possible_cpus() *
1758                               sizeof(pages[0]));
1759        pages = alloc_bootmem(pages_size);
1760
1761        /* allocate pages */
1762        j = 0;
1763        for (unit = 0; unit < num_possible_cpus(); unit++)
1764                for (i = 0; i < unit_pages; i++) {
1765                        unsigned int cpu = ai->groups[0].cpu_map[unit];
1766                        void *ptr;
1767
1768                        ptr = alloc_fn(cpu, PAGE_SIZE, PAGE_SIZE);
1769                        if (!ptr) {
1770                                pr_warning("PERCPU: failed to allocate %s page "
1771                                           "for cpu%u\n", psize_str, cpu);
1772                                goto enomem;
1773                        }
1774                        /* kmemleak tracks the percpu allocations separately */
1775                        kmemleak_free(ptr);
1776                        pages[j++] = virt_to_page(ptr);
1777                }
1778
1779        /* allocate vm area, map the pages and copy static data */
1780        vm.flags = VM_ALLOC;
1781        vm.size = num_possible_cpus() * ai->unit_size;
1782        vm_area_register_early(&vm, PAGE_SIZE);
1783
1784        for (unit = 0; unit < num_possible_cpus(); unit++) {
1785                unsigned long unit_addr =
1786                        (unsigned long)vm.addr + unit * ai->unit_size;
1787
1788                for (i = 0; i < unit_pages; i++)
1789                        populate_pte_fn(unit_addr + (i << PAGE_SHIFT));
1790
1791                /* pte already populated, the following shouldn't fail */
1792                rc = __pcpu_map_pages(unit_addr, &pages[unit * unit_pages],
1793                                      unit_pages);
1794                if (rc < 0)
1795                        panic("failed to map percpu area, err=%d\n", rc);
1796
1797                /*
1798                 * FIXME: Archs with virtual cache should flush local
1799                 * cache for the linear mapping here - something
1800                 * equivalent to flush_cache_vmap() on the local cpu.
1801                 * flush_cache_vmap() can't be used as most supporting
1802                 * data structures are not set up yet.
1803                 */
1804
1805                /* copy static data */
1806                memcpy((void *)unit_addr, __per_cpu_load, ai->static_size);
1807        }
1808
1809        /* we're ready, commit */
1810        pr_info("PERCPU: %d %s pages/cpu @%p s%zu r%zu d%zu\n",
1811                unit_pages, psize_str, vm.addr, ai->static_size,
1812                ai->reserved_size, ai->dyn_size);
1813
1814        rc = pcpu_setup_first_chunk(ai, vm.addr);
1815        goto out_free_ar;
1816
1817enomem:
1818        while (--j >= 0)
1819                free_fn(page_address(pages[j]), PAGE_SIZE);
1820        rc = -ENOMEM;
1821out_free_ar:
1822        free_bootmem(__pa(pages), pages_size);
1823        pcpu_free_alloc_info(ai);
1824        return rc;
1825}
1826#endif /* BUILD_PAGE_FIRST_CHUNK */
1827
1828#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
1829/*
1830 * Generic SMP percpu area setup.
1831 *
1832 * The embedding helper is used because its behavior closely resembles
1833 * the original non-dynamic generic percpu area setup.  This is
1834 * important because many archs have addressing restrictions and might
1835 * fail if the percpu area is located far away from the previous
1836 * location.  As an added bonus, in non-NUMA cases, embedding is
1837 * generally a good idea TLB-wise because percpu area can piggy back
1838 * on the physical linear memory mapping which uses large page
1839 * mappings on applicable archs.
1840 */
1841unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
1842EXPORT_SYMBOL(__per_cpu_offset);
1843
1844static void * __init pcpu_dfl_fc_alloc(unsigned int cpu, size_t size,
1845                                       size_t align)
1846{
1847        return __alloc_bootmem_nopanic(size, align, __pa(MAX_DMA_ADDRESS));
1848}
1849
1850static void __init pcpu_dfl_fc_free(void *ptr, size_t size)
1851{
1852        free_bootmem(__pa(ptr), size);
1853}
1854
1855void __init setup_per_cpu_areas(void)
1856{
1857        unsigned long delta;
1858        unsigned int cpu;
1859        int rc;
1860
1861        /*
1862         * Always reserve area for module percpu variables.  That's
1863         * what the legacy allocator did.
1864         */
1865        rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
1866                                    PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL,
1867                                    pcpu_dfl_fc_alloc, pcpu_dfl_fc_free);
1868        if (rc < 0)
1869                panic("Failed to initialize percpu areas.");
1870
1871        delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
1872        for_each_possible_cpu(cpu)
1873                __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
1874}
1875#endif  /* CONFIG_HAVE_SETUP_PER_CPU_AREA */
1876
1877#else   /* CONFIG_SMP */
1878
1879/*
1880 * UP percpu area setup.
1881 *
1882 * UP always uses km-based percpu allocator with identity mapping.
1883 * Static percpu variables are indistinguishable from the usual static
1884 * variables and don't require any special preparation.
1885 */
1886void __init setup_per_cpu_areas(void)
1887{
1888        const size_t unit_size =
1889                roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE,
1890                                         PERCPU_DYNAMIC_RESERVE));
1891        struct pcpu_alloc_info *ai;
1892        void *fc;
1893
1894        ai = pcpu_alloc_alloc_info(1, 1);
1895        fc = __alloc_bootmem(unit_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
1896        if (!ai || !fc)
1897                panic("Failed to allocate memory for percpu areas.");
1898        /* kmemleak tracks the percpu allocations separately */
1899        kmemleak_free(fc);
1900
1901        ai->dyn_size = unit_size;
1902        ai->unit_size = unit_size;
1903        ai->atom_size = unit_size;
1904        ai->alloc_size = unit_size;
1905        ai->groups[0].nr_units = 1;
1906        ai->groups[0].cpu_map[0] = 0;
1907
1908        if (pcpu_setup_first_chunk(ai, fc) < 0)
1909                panic("Failed to initialize percpu areas.");
1910}
1911
1912#endif  /* CONFIG_SMP */
1913
1914/*
1915 * First and reserved chunks are initialized with temporary allocation
1916 * map in initdata so that they can be used before slab is online.
1917 * This function is called after slab is brought up and replaces those
1918 * with properly allocated maps.
1919 */
1920void __init percpu_init_late(void)
1921{
1922        struct pcpu_chunk *target_chunks[] =
1923                { pcpu_first_chunk, pcpu_reserved_chunk, NULL };
1924        struct pcpu_chunk *chunk;
1925        unsigned long flags;
1926        int i;
1927
1928        for (i = 0; (chunk = target_chunks[i]); i++) {
1929                int *map;
1930                const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]);
1931
1932                BUILD_BUG_ON(size > PAGE_SIZE);
1933
1934                map = pcpu_mem_zalloc(size);
1935                BUG_ON(!map);
1936
1937                spin_lock_irqsave(&pcpu_lock, flags);
1938                memcpy(map, chunk->map, size);
1939                chunk->map = map;
1940                spin_unlock_irqrestore(&pcpu_lock, flags);
1941        }
1942}
1943
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