Root/mm/vmalloc.c

1/*
2 * linux/mm/vmalloc.c
3 *
4 * Copyright (C) 1993 Linus Torvalds
5 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
6 * SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
7 * Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
8 * Numa awareness, Christoph Lameter, SGI, June 2005
9 */
10
11#include <linux/vmalloc.h>
12#include <linux/mm.h>
13#include <linux/module.h>
14#include <linux/highmem.h>
15#include <linux/sched.h>
16#include <linux/slab.h>
17#include <linux/spinlock.h>
18#include <linux/interrupt.h>
19#include <linux/proc_fs.h>
20#include <linux/seq_file.h>
21#include <linux/debugobjects.h>
22#include <linux/kallsyms.h>
23#include <linux/list.h>
24#include <linux/rbtree.h>
25#include <linux/radix-tree.h>
26#include <linux/rcupdate.h>
27#include <linux/pfn.h>
28#include <linux/kmemleak.h>
29#include <linux/atomic.h>
30#include <asm/uaccess.h>
31#include <asm/tlbflush.h>
32#include <asm/shmparam.h>
33
34/*** Page table manipulation functions ***/
35
36static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
37{
38    pte_t *pte;
39
40    pte = pte_offset_kernel(pmd, addr);
41    do {
42        pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
43        WARN_ON(!pte_none(ptent) && !pte_present(ptent));
44    } while (pte++, addr += PAGE_SIZE, addr != end);
45}
46
47static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
48{
49    pmd_t *pmd;
50    unsigned long next;
51
52    pmd = pmd_offset(pud, addr);
53    do {
54        next = pmd_addr_end(addr, end);
55        if (pmd_none_or_clear_bad(pmd))
56            continue;
57        vunmap_pte_range(pmd, addr, next);
58    } while (pmd++, addr = next, addr != end);
59}
60
61static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end)
62{
63    pud_t *pud;
64    unsigned long next;
65
66    pud = pud_offset(pgd, addr);
67    do {
68        next = pud_addr_end(addr, end);
69        if (pud_none_or_clear_bad(pud))
70            continue;
71        vunmap_pmd_range(pud, addr, next);
72    } while (pud++, addr = next, addr != end);
73}
74
75static void vunmap_page_range(unsigned long addr, unsigned long end)
76{
77    pgd_t *pgd;
78    unsigned long next;
79
80    BUG_ON(addr >= end);
81    pgd = pgd_offset_k(addr);
82    do {
83        next = pgd_addr_end(addr, end);
84        if (pgd_none_or_clear_bad(pgd))
85            continue;
86        vunmap_pud_range(pgd, addr, next);
87    } while (pgd++, addr = next, addr != end);
88}
89
90static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
91        unsigned long end, pgprot_t prot, struct page **pages, int *nr)
92{
93    pte_t *pte;
94
95    /*
96     * nr is a running index into the array which helps higher level
97     * callers keep track of where we're up to.
98     */
99
100    pte = pte_alloc_kernel(pmd, addr);
101    if (!pte)
102        return -ENOMEM;
103    do {
104        struct page *page = pages[*nr];
105
106        if (WARN_ON(!pte_none(*pte)))
107            return -EBUSY;
108        if (WARN_ON(!page))
109            return -ENOMEM;
110        set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
111        (*nr)++;
112    } while (pte++, addr += PAGE_SIZE, addr != end);
113    return 0;
114}
115
116static int vmap_pmd_range(pud_t *pud, unsigned long addr,
117        unsigned long end, pgprot_t prot, struct page **pages, int *nr)
118{
119    pmd_t *pmd;
120    unsigned long next;
121
122    pmd = pmd_alloc(&init_mm, pud, addr);
123    if (!pmd)
124        return -ENOMEM;
125    do {
126        next = pmd_addr_end(addr, end);
127        if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
128            return -ENOMEM;
129    } while (pmd++, addr = next, addr != end);
130    return 0;
131}
132
133static int vmap_pud_range(pgd_t *pgd, unsigned long addr,
134        unsigned long end, pgprot_t prot, struct page **pages, int *nr)
135{
136    pud_t *pud;
137    unsigned long next;
138
139    pud = pud_alloc(&init_mm, pgd, addr);
140    if (!pud)
141        return -ENOMEM;
142    do {
143        next = pud_addr_end(addr, end);
144        if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
145            return -ENOMEM;
146    } while (pud++, addr = next, addr != end);
147    return 0;
148}
149
150/*
151 * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and
152 * will have pfns corresponding to the "pages" array.
153 *
154 * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N]
155 */
156static int vmap_page_range_noflush(unsigned long start, unsigned long end,
157                   pgprot_t prot, struct page **pages)
158{
159    pgd_t *pgd;
160    unsigned long next;
161    unsigned long addr = start;
162    int err = 0;
163    int nr = 0;
164
165    BUG_ON(addr >= end);
166    pgd = pgd_offset_k(addr);
167    do {
168        next = pgd_addr_end(addr, end);
169        err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
170        if (err)
171            return err;
172    } while (pgd++, addr = next, addr != end);
173
174    return nr;
175}
176
177static int vmap_page_range(unsigned long start, unsigned long end,
178               pgprot_t prot, struct page **pages)
179{
180    int ret;
181
182    ret = vmap_page_range_noflush(start, end, prot, pages);
183    flush_cache_vmap(start, end);
184    return ret;
185}
186
187int is_vmalloc_or_module_addr(const void *x)
188{
189    /*
190     * ARM, x86-64 and sparc64 put modules in a special place,
191     * and fall back on vmalloc() if that fails. Others
192     * just put it in the vmalloc space.
193     */
194#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
195    unsigned long addr = (unsigned long)x;
196    if (addr >= MODULES_VADDR && addr < MODULES_END)
197        return 1;
198#endif
199    return is_vmalloc_addr(x);
200}
201
202/*
203 * Walk a vmap address to the struct page it maps.
204 */
205struct page *vmalloc_to_page(const void *vmalloc_addr)
206{
207    unsigned long addr = (unsigned long) vmalloc_addr;
208    struct page *page = NULL;
209    pgd_t *pgd = pgd_offset_k(addr);
210
211    /*
212     * XXX we might need to change this if we add VIRTUAL_BUG_ON for
213     * architectures that do not vmalloc module space
214     */
215    VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
216
217    if (!pgd_none(*pgd)) {
218        pud_t *pud = pud_offset(pgd, addr);
219        if (!pud_none(*pud)) {
220            pmd_t *pmd = pmd_offset(pud, addr);
221            if (!pmd_none(*pmd)) {
222                pte_t *ptep, pte;
223
224                ptep = pte_offset_map(pmd, addr);
225                pte = *ptep;
226                if (pte_present(pte))
227                    page = pte_page(pte);
228                pte_unmap(ptep);
229            }
230        }
231    }
232    return page;
233}
234EXPORT_SYMBOL(vmalloc_to_page);
235
236/*
237 * Map a vmalloc()-space virtual address to the physical page frame number.
238 */
239unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
240{
241    return page_to_pfn(vmalloc_to_page(vmalloc_addr));
242}
243EXPORT_SYMBOL(vmalloc_to_pfn);
244
245
246/*** Global kva allocator ***/
247
248#define VM_LAZY_FREE 0x01
249#define VM_LAZY_FREEING 0x02
250#define VM_VM_AREA 0x04
251
252struct vmap_area {
253    unsigned long va_start;
254    unsigned long va_end;
255    unsigned long flags;
256    struct rb_node rb_node; /* address sorted rbtree */
257    struct list_head list; /* address sorted list */
258    struct list_head purge_list; /* "lazy purge" list */
259    struct vm_struct *vm;
260    struct rcu_head rcu_head;
261};
262
263static DEFINE_SPINLOCK(vmap_area_lock);
264static LIST_HEAD(vmap_area_list);
265static struct rb_root vmap_area_root = RB_ROOT;
266
267/* The vmap cache globals are protected by vmap_area_lock */
268static struct rb_node *free_vmap_cache;
269static unsigned long cached_hole_size;
270static unsigned long cached_vstart;
271static unsigned long cached_align;
272
273static unsigned long vmap_area_pcpu_hole;
274
275static struct vmap_area *__find_vmap_area(unsigned long addr)
276{
277    struct rb_node *n = vmap_area_root.rb_node;
278
279    while (n) {
280        struct vmap_area *va;
281
282        va = rb_entry(n, struct vmap_area, rb_node);
283        if (addr < va->va_start)
284            n = n->rb_left;
285        else if (addr > va->va_start)
286            n = n->rb_right;
287        else
288            return va;
289    }
290
291    return NULL;
292}
293
294static void __insert_vmap_area(struct vmap_area *va)
295{
296    struct rb_node **p = &vmap_area_root.rb_node;
297    struct rb_node *parent = NULL;
298    struct rb_node *tmp;
299
300    while (*p) {
301        struct vmap_area *tmp_va;
302
303        parent = *p;
304        tmp_va = rb_entry(parent, struct vmap_area, rb_node);
305        if (va->va_start < tmp_va->va_end)
306            p = &(*p)->rb_left;
307        else if (va->va_end > tmp_va->va_start)
308            p = &(*p)->rb_right;
309        else
310            BUG();
311    }
312
313    rb_link_node(&va->rb_node, parent, p);
314    rb_insert_color(&va->rb_node, &vmap_area_root);
315
316    /* address-sort this list so it is usable like the vmlist */
317    tmp = rb_prev(&va->rb_node);
318    if (tmp) {
319        struct vmap_area *prev;
320        prev = rb_entry(tmp, struct vmap_area, rb_node);
321        list_add_rcu(&va->list, &prev->list);
322    } else
323        list_add_rcu(&va->list, &vmap_area_list);
324}
325
326static void purge_vmap_area_lazy(void);
327
328/*
329 * Allocate a region of KVA of the specified size and alignment, within the
330 * vstart and vend.
331 */
332static struct vmap_area *alloc_vmap_area(unsigned long size,
333                unsigned long align,
334                unsigned long vstart, unsigned long vend,
335                int node, gfp_t gfp_mask)
336{
337    struct vmap_area *va;
338    struct rb_node *n;
339    unsigned long addr;
340    int purged = 0;
341    struct vmap_area *first;
342
343    BUG_ON(!size);
344    BUG_ON(size & ~PAGE_MASK);
345    BUG_ON(!is_power_of_2(align));
346
347    va = kmalloc_node(sizeof(struct vmap_area),
348            gfp_mask & GFP_RECLAIM_MASK, node);
349    if (unlikely(!va))
350        return ERR_PTR(-ENOMEM);
351
352retry:
353    spin_lock(&vmap_area_lock);
354    /*
355     * Invalidate cache if we have more permissive parameters.
356     * cached_hole_size notes the largest hole noticed _below_
357     * the vmap_area cached in free_vmap_cache: if size fits
358     * into that hole, we want to scan from vstart to reuse
359     * the hole instead of allocating above free_vmap_cache.
360     * Note that __free_vmap_area may update free_vmap_cache
361     * without updating cached_hole_size or cached_align.
362     */
363    if (!free_vmap_cache ||
364            size < cached_hole_size ||
365            vstart < cached_vstart ||
366            align < cached_align) {
367nocache:
368        cached_hole_size = 0;
369        free_vmap_cache = NULL;
370    }
371    /* record if we encounter less permissive parameters */
372    cached_vstart = vstart;
373    cached_align = align;
374
375    /* find starting point for our search */
376    if (free_vmap_cache) {
377        first = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
378        addr = ALIGN(first->va_end, align);
379        if (addr < vstart)
380            goto nocache;
381        if (addr + size - 1 < addr)
382            goto overflow;
383
384    } else {
385        addr = ALIGN(vstart, align);
386        if (addr + size - 1 < addr)
387            goto overflow;
388
389        n = vmap_area_root.rb_node;
390        first = NULL;
391
392        while (n) {
393            struct vmap_area *tmp;
394            tmp = rb_entry(n, struct vmap_area, rb_node);
395            if (tmp->va_end >= addr) {
396                first = tmp;
397                if (tmp->va_start <= addr)
398                    break;
399                n = n->rb_left;
400            } else
401                n = n->rb_right;
402        }
403
404        if (!first)
405            goto found;
406    }
407
408    /* from the starting point, walk areas until a suitable hole is found */
409    while (addr + size > first->va_start && addr + size <= vend) {
410        if (addr + cached_hole_size < first->va_start)
411            cached_hole_size = first->va_start - addr;
412        addr = ALIGN(first->va_end, align);
413        if (addr + size - 1 < addr)
414            goto overflow;
415
416        if (list_is_last(&first->list, &vmap_area_list))
417            goto found;
418
419        first = list_entry(first->list.next,
420                struct vmap_area, list);
421    }
422
423found:
424    if (addr + size > vend)
425        goto overflow;
426
427    va->va_start = addr;
428    va->va_end = addr + size;
429    va->flags = 0;
430    __insert_vmap_area(va);
431    free_vmap_cache = &va->rb_node;
432    spin_unlock(&vmap_area_lock);
433
434    BUG_ON(va->va_start & (align-1));
435    BUG_ON(va->va_start < vstart);
436    BUG_ON(va->va_end > vend);
437
438    return va;
439
440overflow:
441    spin_unlock(&vmap_area_lock);
442    if (!purged) {
443        purge_vmap_area_lazy();
444        purged = 1;
445        goto retry;
446    }
447    if (printk_ratelimit())
448        printk(KERN_WARNING
449            "vmap allocation for size %lu failed: "
450            "use vmalloc=<size> to increase size.\n", size);
451    kfree(va);
452    return ERR_PTR(-EBUSY);
453}
454
455static void __free_vmap_area(struct vmap_area *va)
456{
457    BUG_ON(RB_EMPTY_NODE(&va->rb_node));
458
459    if (free_vmap_cache) {
460        if (va->va_end < cached_vstart) {
461            free_vmap_cache = NULL;
462        } else {
463            struct vmap_area *cache;
464            cache = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
465            if (va->va_start <= cache->va_start) {
466                free_vmap_cache = rb_prev(&va->rb_node);
467                /*
468                 * We don't try to update cached_hole_size or
469                 * cached_align, but it won't go very wrong.
470                 */
471            }
472        }
473    }
474    rb_erase(&va->rb_node, &vmap_area_root);
475    RB_CLEAR_NODE(&va->rb_node);
476    list_del_rcu(&va->list);
477
478    /*
479     * Track the highest possible candidate for pcpu area
480     * allocation. Areas outside of vmalloc area can be returned
481     * here too, consider only end addresses which fall inside
482     * vmalloc area proper.
483     */
484    if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
485        vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);
486
487    kfree_rcu(va, rcu_head);
488}
489
490/*
491 * Free a region of KVA allocated by alloc_vmap_area
492 */
493static void free_vmap_area(struct vmap_area *va)
494{
495    spin_lock(&vmap_area_lock);
496    __free_vmap_area(va);
497    spin_unlock(&vmap_area_lock);
498}
499
500/*
501 * Clear the pagetable entries of a given vmap_area
502 */
503static void unmap_vmap_area(struct vmap_area *va)
504{
505    vunmap_page_range(va->va_start, va->va_end);
506}
507
508static void vmap_debug_free_range(unsigned long start, unsigned long end)
509{
510    /*
511     * Unmap page tables and force a TLB flush immediately if
512     * CONFIG_DEBUG_PAGEALLOC is set. This catches use after free
513     * bugs similarly to those in linear kernel virtual address
514     * space after a page has been freed.
515     *
516     * All the lazy freeing logic is still retained, in order to
517     * minimise intrusiveness of this debugging feature.
518     *
519     * This is going to be *slow* (linear kernel virtual address
520     * debugging doesn't do a broadcast TLB flush so it is a lot
521     * faster).
522     */
523#ifdef CONFIG_DEBUG_PAGEALLOC
524    vunmap_page_range(start, end);
525    flush_tlb_kernel_range(start, end);
526#endif
527}
528
529/*
530 * lazy_max_pages is the maximum amount of virtual address space we gather up
531 * before attempting to purge with a TLB flush.
532 *
533 * There is a tradeoff here: a larger number will cover more kernel page tables
534 * and take slightly longer to purge, but it will linearly reduce the number of
535 * global TLB flushes that must be performed. It would seem natural to scale
536 * this number up linearly with the number of CPUs (because vmapping activity
537 * could also scale linearly with the number of CPUs), however it is likely
538 * that in practice, workloads might be constrained in other ways that mean
539 * vmap activity will not scale linearly with CPUs. Also, I want to be
540 * conservative and not introduce a big latency on huge systems, so go with
541 * a less aggressive log scale. It will still be an improvement over the old
542 * code, and it will be simple to change the scale factor if we find that it
543 * becomes a problem on bigger systems.
544 */
545static unsigned long lazy_max_pages(void)
546{
547    unsigned int log;
548
549    log = fls(num_online_cpus());
550
551    return log * (32UL * 1024 * 1024 / PAGE_SIZE);
552}
553
554static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
555
556/* for per-CPU blocks */
557static void purge_fragmented_blocks_allcpus(void);
558
559/*
560 * called before a call to iounmap() if the caller wants vm_area_struct's
561 * immediately freed.
562 */
563void set_iounmap_nonlazy(void)
564{
565    atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
566}
567
568/*
569 * Purges all lazily-freed vmap areas.
570 *
571 * If sync is 0 then don't purge if there is already a purge in progress.
572 * If force_flush is 1, then flush kernel TLBs between *start and *end even
573 * if we found no lazy vmap areas to unmap (callers can use this to optimise
574 * their own TLB flushing).
575 * Returns with *start = min(*start, lowest purged address)
576 * *end = max(*end, highest purged address)
577 */
578static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
579                    int sync, int force_flush)
580{
581    static DEFINE_SPINLOCK(purge_lock);
582    LIST_HEAD(valist);
583    struct vmap_area *va;
584    struct vmap_area *n_va;
585    int nr = 0;
586
587    /*
588     * If sync is 0 but force_flush is 1, we'll go sync anyway but callers
589     * should not expect such behaviour. This just simplifies locking for
590     * the case that isn't actually used at the moment anyway.
591     */
592    if (!sync && !force_flush) {
593        if (!spin_trylock(&purge_lock))
594            return;
595    } else
596        spin_lock(&purge_lock);
597
598    if (sync)
599        purge_fragmented_blocks_allcpus();
600
601    rcu_read_lock();
602    list_for_each_entry_rcu(va, &vmap_area_list, list) {
603        if (va->flags & VM_LAZY_FREE) {
604            if (va->va_start < *start)
605                *start = va->va_start;
606            if (va->va_end > *end)
607                *end = va->va_end;
608            nr += (va->va_end - va->va_start) >> PAGE_SHIFT;
609            list_add_tail(&va->purge_list, &valist);
610            va->flags |= VM_LAZY_FREEING;
611            va->flags &= ~VM_LAZY_FREE;
612        }
613    }
614    rcu_read_unlock();
615
616    if (nr)
617        atomic_sub(nr, &vmap_lazy_nr);
618
619    if (nr || force_flush)
620        flush_tlb_kernel_range(*start, *end);
621
622    if (nr) {
623        spin_lock(&vmap_area_lock);
624        list_for_each_entry_safe(va, n_va, &valist, purge_list)
625            __free_vmap_area(va);
626        spin_unlock(&vmap_area_lock);
627    }
628    spin_unlock(&purge_lock);
629}
630
631/*
632 * Kick off a purge of the outstanding lazy areas. Don't bother if somebody
633 * is already purging.
634 */
635static void try_purge_vmap_area_lazy(void)
636{
637    unsigned long start = ULONG_MAX, end = 0;
638
639    __purge_vmap_area_lazy(&start, &end, 0, 0);
640}
641
642/*
643 * Kick off a purge of the outstanding lazy areas.
644 */
645static void purge_vmap_area_lazy(void)
646{
647    unsigned long start = ULONG_MAX, end = 0;
648
649    __purge_vmap_area_lazy(&start, &end, 1, 0);
650}
651
652/*
653 * Free a vmap area, caller ensuring that the area has been unmapped
654 * and flush_cache_vunmap had been called for the correct range
655 * previously.
656 */
657static void free_vmap_area_noflush(struct vmap_area *va)
658{
659    va->flags |= VM_LAZY_FREE;
660    atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr);
661    if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages()))
662        try_purge_vmap_area_lazy();
663}
664
665/*
666 * Free and unmap a vmap area, caller ensuring flush_cache_vunmap had been
667 * called for the correct range previously.
668 */
669static void free_unmap_vmap_area_noflush(struct vmap_area *va)
670{
671    unmap_vmap_area(va);
672    free_vmap_area_noflush(va);
673}
674
675/*
676 * Free and unmap a vmap area
677 */
678static void free_unmap_vmap_area(struct vmap_area *va)
679{
680    flush_cache_vunmap(va->va_start, va->va_end);
681    free_unmap_vmap_area_noflush(va);
682}
683
684static struct vmap_area *find_vmap_area(unsigned long addr)
685{
686    struct vmap_area *va;
687
688    spin_lock(&vmap_area_lock);
689    va = __find_vmap_area(addr);
690    spin_unlock(&vmap_area_lock);
691
692    return va;
693}
694
695static void free_unmap_vmap_area_addr(unsigned long addr)
696{
697    struct vmap_area *va;
698
699    va = find_vmap_area(addr);
700    BUG_ON(!va);
701    free_unmap_vmap_area(va);
702}
703
704
705/*** Per cpu kva allocator ***/
706
707/*
708 * vmap space is limited especially on 32 bit architectures. Ensure there is
709 * room for at least 16 percpu vmap blocks per CPU.
710 */
711/*
712 * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
713 * to #define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START). Guess
714 * instead (we just need a rough idea)
715 */
716#if BITS_PER_LONG == 32
717#define VMALLOC_SPACE (128UL*1024*1024)
718#else
719#define VMALLOC_SPACE (128UL*1024*1024*1024)
720#endif
721
722#define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE)
723#define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */
724#define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */
725#define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2)
726#define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */
727#define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */
728#define VMAP_BBMAP_BITS \
729        VMAP_MIN(VMAP_BBMAP_BITS_MAX, \
730        VMAP_MAX(VMAP_BBMAP_BITS_MIN, \
731            VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
732
733#define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
734
735static bool vmap_initialized __read_mostly = false;
736
737struct vmap_block_queue {
738    spinlock_t lock;
739    struct list_head free;
740};
741
742struct vmap_block {
743    spinlock_t lock;
744    struct vmap_area *va;
745    struct vmap_block_queue *vbq;
746    unsigned long free, dirty;
747    DECLARE_BITMAP(alloc_map, VMAP_BBMAP_BITS);
748    DECLARE_BITMAP(dirty_map, VMAP_BBMAP_BITS);
749    struct list_head free_list;
750    struct rcu_head rcu_head;
751    struct list_head purge;
752};
753
754/* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
755static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
756
757/*
758 * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block
759 * in the free path. Could get rid of this if we change the API to return a
760 * "cookie" from alloc, to be passed to free. But no big deal yet.
761 */
762static DEFINE_SPINLOCK(vmap_block_tree_lock);
763static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
764
765/*
766 * We should probably have a fallback mechanism to allocate virtual memory
767 * out of partially filled vmap blocks. However vmap block sizing should be
768 * fairly reasonable according to the vmalloc size, so it shouldn't be a
769 * big problem.
770 */
771
772static unsigned long addr_to_vb_idx(unsigned long addr)
773{
774    addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
775    addr /= VMAP_BLOCK_SIZE;
776    return addr;
777}
778
779static struct vmap_block *new_vmap_block(gfp_t gfp_mask)
780{
781    struct vmap_block_queue *vbq;
782    struct vmap_block *vb;
783    struct vmap_area *va;
784    unsigned long vb_idx;
785    int node, err;
786
787    node = numa_node_id();
788
789    vb = kmalloc_node(sizeof(struct vmap_block),
790            gfp_mask & GFP_RECLAIM_MASK, node);
791    if (unlikely(!vb))
792        return ERR_PTR(-ENOMEM);
793
794    va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
795                    VMALLOC_START, VMALLOC_END,
796                    node, gfp_mask);
797    if (IS_ERR(va)) {
798        kfree(vb);
799        return ERR_CAST(va);
800    }
801
802    err = radix_tree_preload(gfp_mask);
803    if (unlikely(err)) {
804        kfree(vb);
805        free_vmap_area(va);
806        return ERR_PTR(err);
807    }
808
809    spin_lock_init(&vb->lock);
810    vb->va = va;
811    vb->free = VMAP_BBMAP_BITS;
812    vb->dirty = 0;
813    bitmap_zero(vb->alloc_map, VMAP_BBMAP_BITS);
814    bitmap_zero(vb->dirty_map, VMAP_BBMAP_BITS);
815    INIT_LIST_HEAD(&vb->free_list);
816
817    vb_idx = addr_to_vb_idx(va->va_start);
818    spin_lock(&vmap_block_tree_lock);
819    err = radix_tree_insert(&vmap_block_tree, vb_idx, vb);
820    spin_unlock(&vmap_block_tree_lock);
821    BUG_ON(err);
822    radix_tree_preload_end();
823
824    vbq = &get_cpu_var(vmap_block_queue);
825    vb->vbq = vbq;
826    spin_lock(&vbq->lock);
827    list_add_rcu(&vb->free_list, &vbq->free);
828    spin_unlock(&vbq->lock);
829    put_cpu_var(vmap_block_queue);
830
831    return vb;
832}
833
834static void free_vmap_block(struct vmap_block *vb)
835{
836    struct vmap_block *tmp;
837    unsigned long vb_idx;
838
839    vb_idx = addr_to_vb_idx(vb->va->va_start);
840    spin_lock(&vmap_block_tree_lock);
841    tmp = radix_tree_delete(&vmap_block_tree, vb_idx);
842    spin_unlock(&vmap_block_tree_lock);
843    BUG_ON(tmp != vb);
844
845    free_vmap_area_noflush(vb->va);
846    kfree_rcu(vb, rcu_head);
847}
848
849static void purge_fragmented_blocks(int cpu)
850{
851    LIST_HEAD(purge);
852    struct vmap_block *vb;
853    struct vmap_block *n_vb;
854    struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
855
856    rcu_read_lock();
857    list_for_each_entry_rcu(vb, &vbq->free, free_list) {
858
859        if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
860            continue;
861
862        spin_lock(&vb->lock);
863        if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
864            vb->free = 0; /* prevent further allocs after releasing lock */
865            vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
866            bitmap_fill(vb->alloc_map, VMAP_BBMAP_BITS);
867            bitmap_fill(vb->dirty_map, VMAP_BBMAP_BITS);
868            spin_lock(&vbq->lock);
869            list_del_rcu(&vb->free_list);
870            spin_unlock(&vbq->lock);
871            spin_unlock(&vb->lock);
872            list_add_tail(&vb->purge, &purge);
873        } else
874            spin_unlock(&vb->lock);
875    }
876    rcu_read_unlock();
877
878    list_for_each_entry_safe(vb, n_vb, &purge, purge) {
879        list_del(&vb->purge);
880        free_vmap_block(vb);
881    }
882}
883
884static void purge_fragmented_blocks_thiscpu(void)
885{
886    purge_fragmented_blocks(smp_processor_id());
887}
888
889static void purge_fragmented_blocks_allcpus(void)
890{
891    int cpu;
892
893    for_each_possible_cpu(cpu)
894        purge_fragmented_blocks(cpu);
895}
896
897static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
898{
899    struct vmap_block_queue *vbq;
900    struct vmap_block *vb;
901    unsigned long addr = 0;
902    unsigned int order;
903    int purge = 0;
904
905    BUG_ON(size & ~PAGE_MASK);
906    BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
907    if (WARN_ON(size == 0)) {
908        /*
909         * Allocating 0 bytes isn't what caller wants since
910         * get_order(0) returns funny result. Just warn and terminate
911         * early.
912         */
913        return NULL;
914    }
915    order = get_order(size);
916
917again:
918    rcu_read_lock();
919    vbq = &get_cpu_var(vmap_block_queue);
920    list_for_each_entry_rcu(vb, &vbq->free, free_list) {
921        int i;
922
923        spin_lock(&vb->lock);
924        if (vb->free < 1UL << order)
925            goto next;
926
927        i = bitmap_find_free_region(vb->alloc_map,
928                        VMAP_BBMAP_BITS, order);
929
930        if (i < 0) {
931            if (vb->free + vb->dirty == VMAP_BBMAP_BITS) {
932                /* fragmented and no outstanding allocations */
933                BUG_ON(vb->dirty != VMAP_BBMAP_BITS);
934                purge = 1;
935            }
936            goto next;
937        }
938        addr = vb->va->va_start + (i << PAGE_SHIFT);
939        BUG_ON(addr_to_vb_idx(addr) !=
940                addr_to_vb_idx(vb->va->va_start));
941        vb->free -= 1UL << order;
942        if (vb->free == 0) {
943            spin_lock(&vbq->lock);
944            list_del_rcu(&vb->free_list);
945            spin_unlock(&vbq->lock);
946        }
947        spin_unlock(&vb->lock);
948        break;
949next:
950        spin_unlock(&vb->lock);
951    }
952
953    if (purge)
954        purge_fragmented_blocks_thiscpu();
955
956    put_cpu_var(vmap_block_queue);
957    rcu_read_unlock();
958
959    if (!addr) {
960        vb = new_vmap_block(gfp_mask);
961        if (IS_ERR(vb))
962            return vb;
963        goto again;
964    }
965
966    return (void *)addr;
967}
968
969static void vb_free(const void *addr, unsigned long size)
970{
971    unsigned long offset;
972    unsigned long vb_idx;
973    unsigned int order;
974    struct vmap_block *vb;
975
976    BUG_ON(size & ~PAGE_MASK);
977    BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
978
979    flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
980
981    order = get_order(size);
982
983    offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
984
985    vb_idx = addr_to_vb_idx((unsigned long)addr);
986    rcu_read_lock();
987    vb = radix_tree_lookup(&vmap_block_tree, vb_idx);
988    rcu_read_unlock();
989    BUG_ON(!vb);
990
991    vunmap_page_range((unsigned long)addr, (unsigned long)addr + size);
992
993    spin_lock(&vb->lock);
994    BUG_ON(bitmap_allocate_region(vb->dirty_map, offset >> PAGE_SHIFT, order));
995
996    vb->dirty += 1UL << order;
997    if (vb->dirty == VMAP_BBMAP_BITS) {
998        BUG_ON(vb->free);
999        spin_unlock(&vb->lock);
1000        free_vmap_block(vb);
1001    } else
1002        spin_unlock(&vb->lock);
1003}
1004
1005/**
1006 * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
1007 *
1008 * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
1009 * to amortize TLB flushing overheads. What this means is that any page you
1010 * have now, may, in a former life, have been mapped into kernel virtual
1011 * address by the vmap layer and so there might be some CPUs with TLB entries
1012 * still referencing that page (additional to the regular 1:1 kernel mapping).
1013 *
1014 * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
1015 * be sure that none of the pages we have control over will have any aliases
1016 * from the vmap layer.
1017 */
1018void vm_unmap_aliases(void)
1019{
1020    unsigned long start = ULONG_MAX, end = 0;
1021    int cpu;
1022    int flush = 0;
1023
1024    if (unlikely(!vmap_initialized))
1025        return;
1026
1027    for_each_possible_cpu(cpu) {
1028        struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
1029        struct vmap_block *vb;
1030
1031        rcu_read_lock();
1032        list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1033            int i;
1034
1035            spin_lock(&vb->lock);
1036            i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS);
1037            while (i < VMAP_BBMAP_BITS) {
1038                unsigned long s, e;
1039                int j;
1040                j = find_next_zero_bit(vb->dirty_map,
1041                    VMAP_BBMAP_BITS, i);
1042
1043                s = vb->va->va_start + (i << PAGE_SHIFT);
1044                e = vb->va->va_start + (j << PAGE_SHIFT);
1045                flush = 1;
1046
1047                if (s < start)
1048                    start = s;
1049                if (e > end)
1050                    end = e;
1051
1052                i = j;
1053                i = find_next_bit(vb->dirty_map,
1054                            VMAP_BBMAP_BITS, i);
1055            }
1056            spin_unlock(&vb->lock);
1057        }
1058        rcu_read_unlock();
1059    }
1060
1061    __purge_vmap_area_lazy(&start, &end, 1, flush);
1062}
1063EXPORT_SYMBOL_GPL(vm_unmap_aliases);
1064
1065/**
1066 * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
1067 * @mem: the pointer returned by vm_map_ram
1068 * @count: the count passed to that vm_map_ram call (cannot unmap partial)
1069 */
1070void vm_unmap_ram(const void *mem, unsigned int count)
1071{
1072    unsigned long size = count << PAGE_SHIFT;
1073    unsigned long addr = (unsigned long)mem;
1074
1075    BUG_ON(!addr);
1076    BUG_ON(addr < VMALLOC_START);
1077    BUG_ON(addr > VMALLOC_END);
1078    BUG_ON(addr & (PAGE_SIZE-1));
1079
1080    debug_check_no_locks_freed(mem, size);
1081    vmap_debug_free_range(addr, addr+size);
1082
1083    if (likely(count <= VMAP_MAX_ALLOC))
1084        vb_free(mem, size);
1085    else
1086        free_unmap_vmap_area_addr(addr);
1087}
1088EXPORT_SYMBOL(vm_unmap_ram);
1089
1090/**
1091 * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
1092 * @pages: an array of pointers to the pages to be mapped
1093 * @count: number of pages
1094 * @node: prefer to allocate data structures on this node
1095 * @prot: memory protection to use. PAGE_KERNEL for regular RAM
1096 *
1097 * Returns: a pointer to the address that has been mapped, or %NULL on failure
1098 */
1099void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
1100{
1101    unsigned long size = count << PAGE_SHIFT;
1102    unsigned long addr;
1103    void *mem;
1104
1105    if (likely(count <= VMAP_MAX_ALLOC)) {
1106        mem = vb_alloc(size, GFP_KERNEL);
1107        if (IS_ERR(mem))
1108            return NULL;
1109        addr = (unsigned long)mem;
1110    } else {
1111        struct vmap_area *va;
1112        va = alloc_vmap_area(size, PAGE_SIZE,
1113                VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
1114        if (IS_ERR(va))
1115            return NULL;
1116
1117        addr = va->va_start;
1118        mem = (void *)addr;
1119    }
1120    if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
1121        vm_unmap_ram(mem, count);
1122        return NULL;
1123    }
1124    return mem;
1125}
1126EXPORT_SYMBOL(vm_map_ram);
1127
1128/**
1129 * vm_area_add_early - add vmap area early during boot
1130 * @vm: vm_struct to add
1131 *
1132 * This function is used to add fixed kernel vm area to vmlist before
1133 * vmalloc_init() is called. @vm->addr, @vm->size, and @vm->flags
1134 * should contain proper values and the other fields should be zero.
1135 *
1136 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1137 */
1138void __init vm_area_add_early(struct vm_struct *vm)
1139{
1140    struct vm_struct *tmp, **p;
1141
1142    BUG_ON(vmap_initialized);
1143    for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1144        if (tmp->addr >= vm->addr) {
1145            BUG_ON(tmp->addr < vm->addr + vm->size);
1146            break;
1147        } else
1148            BUG_ON(tmp->addr + tmp->size > vm->addr);
1149    }
1150    vm->next = *p;
1151    *p = vm;
1152}
1153
1154/**
1155 * vm_area_register_early - register vmap area early during boot
1156 * @vm: vm_struct to register
1157 * @align: requested alignment
1158 *
1159 * This function is used to register kernel vm area before
1160 * vmalloc_init() is called. @vm->size and @vm->flags should contain
1161 * proper values on entry and other fields should be zero. On return,
1162 * vm->addr contains the allocated address.
1163 *
1164 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1165 */
1166void __init vm_area_register_early(struct vm_struct *vm, size_t align)
1167{
1168    static size_t vm_init_off __initdata;
1169    unsigned long addr;
1170
1171    addr = ALIGN(VMALLOC_START + vm_init_off, align);
1172    vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
1173
1174    vm->addr = (void *)addr;
1175
1176    vm_area_add_early(vm);
1177}
1178
1179void __init vmalloc_init(void)
1180{
1181    struct vmap_area *va;
1182    struct vm_struct *tmp;
1183    int i;
1184
1185    for_each_possible_cpu(i) {
1186        struct vmap_block_queue *vbq;
1187
1188        vbq = &per_cpu(vmap_block_queue, i);
1189        spin_lock_init(&vbq->lock);
1190        INIT_LIST_HEAD(&vbq->free);
1191    }
1192
1193    /* Import existing vmlist entries. */
1194    for (tmp = vmlist; tmp; tmp = tmp->next) {
1195        va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT);
1196        va->flags = VM_VM_AREA;
1197        va->va_start = (unsigned long)tmp->addr;
1198        va->va_end = va->va_start + tmp->size;
1199        va->vm = tmp;
1200        __insert_vmap_area(va);
1201    }
1202
1203    vmap_area_pcpu_hole = VMALLOC_END;
1204
1205    vmap_initialized = true;
1206}
1207
1208/**
1209 * map_kernel_range_noflush - map kernel VM area with the specified pages
1210 * @addr: start of the VM area to map
1211 * @size: size of the VM area to map
1212 * @prot: page protection flags to use
1213 * @pages: pages to map
1214 *
1215 * Map PFN_UP(@size) pages at @addr. The VM area @addr and @size
1216 * specify should have been allocated using get_vm_area() and its
1217 * friends.
1218 *
1219 * NOTE:
1220 * This function does NOT do any cache flushing. The caller is
1221 * responsible for calling flush_cache_vmap() on to-be-mapped areas
1222 * before calling this function.
1223 *
1224 * RETURNS:
1225 * The number of pages mapped on success, -errno on failure.
1226 */
1227int map_kernel_range_noflush(unsigned long addr, unsigned long size,
1228                 pgprot_t prot, struct page **pages)
1229{
1230    return vmap_page_range_noflush(addr, addr + size, prot, pages);
1231}
1232
1233/**
1234 * unmap_kernel_range_noflush - unmap kernel VM area
1235 * @addr: start of the VM area to unmap
1236 * @size: size of the VM area to unmap
1237 *
1238 * Unmap PFN_UP(@size) pages at @addr. The VM area @addr and @size
1239 * specify should have been allocated using get_vm_area() and its
1240 * friends.
1241 *
1242 * NOTE:
1243 * This function does NOT do any cache flushing. The caller is
1244 * responsible for calling flush_cache_vunmap() on to-be-mapped areas
1245 * before calling this function and flush_tlb_kernel_range() after.
1246 */
1247void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
1248{
1249    vunmap_page_range(addr, addr + size);
1250}
1251EXPORT_SYMBOL_GPL(unmap_kernel_range_noflush);
1252
1253/**
1254 * unmap_kernel_range - unmap kernel VM area and flush cache and TLB
1255 * @addr: start of the VM area to unmap
1256 * @size: size of the VM area to unmap
1257 *
1258 * Similar to unmap_kernel_range_noflush() but flushes vcache before
1259 * the unmapping and tlb after.
1260 */
1261void unmap_kernel_range(unsigned long addr, unsigned long size)
1262{
1263    unsigned long end = addr + size;
1264
1265    flush_cache_vunmap(addr, end);
1266    vunmap_page_range(addr, end);
1267    flush_tlb_kernel_range(addr, end);
1268}
1269
1270int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
1271{
1272    unsigned long addr = (unsigned long)area->addr;
1273    unsigned long end = addr + area->size - PAGE_SIZE;
1274    int err;
1275
1276    err = vmap_page_range(addr, end, prot, *pages);
1277    if (err > 0) {
1278        *pages += err;
1279        err = 0;
1280    }
1281
1282    return err;
1283}
1284EXPORT_SYMBOL_GPL(map_vm_area);
1285
1286/*** Old vmalloc interfaces ***/
1287DEFINE_RWLOCK(vmlist_lock);
1288struct vm_struct *vmlist;
1289
1290static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1291                  unsigned long flags, const void *caller)
1292{
1293    vm->flags = flags;
1294    vm->addr = (void *)va->va_start;
1295    vm->size = va->va_end - va->va_start;
1296    vm->caller = caller;
1297    va->vm = vm;
1298    va->flags |= VM_VM_AREA;
1299}
1300
1301static void insert_vmalloc_vmlist(struct vm_struct *vm)
1302{
1303    struct vm_struct *tmp, **p;
1304
1305    vm->flags &= ~VM_UNLIST;
1306    write_lock(&vmlist_lock);
1307    for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1308        if (tmp->addr >= vm->addr)
1309            break;
1310    }
1311    vm->next = *p;
1312    *p = vm;
1313    write_unlock(&vmlist_lock);
1314}
1315
1316static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1317                  unsigned long flags, const void *caller)
1318{
1319    setup_vmalloc_vm(vm, va, flags, caller);
1320    insert_vmalloc_vmlist(vm);
1321}
1322
1323static struct vm_struct *__get_vm_area_node(unsigned long size,
1324        unsigned long align, unsigned long flags, unsigned long start,
1325        unsigned long end, int node, gfp_t gfp_mask, const void *caller)
1326{
1327    struct vmap_area *va;
1328    struct vm_struct *area;
1329
1330    BUG_ON(in_interrupt());
1331    if (flags & VM_IOREMAP) {
1332        int bit = fls(size);
1333
1334        if (bit > IOREMAP_MAX_ORDER)
1335            bit = IOREMAP_MAX_ORDER;
1336        else if (bit < PAGE_SHIFT)
1337            bit = PAGE_SHIFT;
1338
1339        align = 1ul << bit;
1340    }
1341
1342    size = PAGE_ALIGN(size);
1343    if (unlikely(!size))
1344        return NULL;
1345
1346    area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
1347    if (unlikely(!area))
1348        return NULL;
1349
1350    /*
1351     * We always allocate a guard page.
1352     */
1353    size += PAGE_SIZE;
1354
1355    va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
1356    if (IS_ERR(va)) {
1357        kfree(area);
1358        return NULL;
1359    }
1360
1361    /*
1362     * When this function is called from __vmalloc_node_range,
1363     * we do not add vm_struct to vmlist here to avoid
1364     * accessing uninitialized members of vm_struct such as
1365     * pages and nr_pages fields. They will be set later.
1366     * To distinguish it from others, we use a VM_UNLIST flag.
1367     */
1368    if (flags & VM_UNLIST)
1369        setup_vmalloc_vm(area, va, flags, caller);
1370    else
1371        insert_vmalloc_vm(area, va, flags, caller);
1372
1373    return area;
1374}
1375
1376struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
1377                unsigned long start, unsigned long end)
1378{
1379    return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
1380                        __builtin_return_address(0));
1381}
1382EXPORT_SYMBOL_GPL(__get_vm_area);
1383
1384struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
1385                       unsigned long start, unsigned long end,
1386                       const void *caller)
1387{
1388    return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
1389                  caller);
1390}
1391
1392/**
1393 * get_vm_area - reserve a contiguous kernel virtual area
1394 * @size: size of the area
1395 * @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC
1396 *
1397 * Search an area of @size in the kernel virtual mapping area,
1398 * and reserved it for out purposes. Returns the area descriptor
1399 * on success or %NULL on failure.
1400 */
1401struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
1402{
1403    return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1404                -1, GFP_KERNEL, __builtin_return_address(0));
1405}
1406
1407struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
1408                const void *caller)
1409{
1410    return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1411                        -1, GFP_KERNEL, caller);
1412}
1413
1414/**
1415 * find_vm_area - find a continuous kernel virtual area
1416 * @addr: base address
1417 *
1418 * Search for the kernel VM area starting at @addr, and return it.
1419 * It is up to the caller to do all required locking to keep the returned
1420 * pointer valid.
1421 */
1422struct vm_struct *find_vm_area(const void *addr)
1423{
1424    struct vmap_area *va;
1425
1426    va = find_vmap_area((unsigned long)addr);
1427    if (va && va->flags & VM_VM_AREA)
1428        return va->vm;
1429
1430    return NULL;
1431}
1432
1433/**
1434 * remove_vm_area - find and remove a continuous kernel virtual area
1435 * @addr: base address
1436 *
1437 * Search for the kernel VM area starting at @addr, and remove it.
1438 * This function returns the found VM area, but using it is NOT safe
1439 * on SMP machines, except for its size or flags.
1440 */
1441struct vm_struct *remove_vm_area(const void *addr)
1442{
1443    struct vmap_area *va;
1444
1445    va = find_vmap_area((unsigned long)addr);
1446    if (va && va->flags & VM_VM_AREA) {
1447        struct vm_struct *vm = va->vm;
1448
1449        if (!(vm->flags & VM_UNLIST)) {
1450            struct vm_struct *tmp, **p;
1451            /*
1452             * remove from list and disallow access to
1453             * this vm_struct before unmap. (address range
1454             * confliction is maintained by vmap.)
1455             */
1456            write_lock(&vmlist_lock);
1457            for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next)
1458                ;
1459            *p = tmp->next;
1460            write_unlock(&vmlist_lock);
1461        }
1462
1463        vmap_debug_free_range(va->va_start, va->va_end);
1464        free_unmap_vmap_area(va);
1465        vm->size -= PAGE_SIZE;
1466
1467        return vm;
1468    }
1469    return NULL;
1470}
1471
1472static void __vunmap(const void *addr, int deallocate_pages)
1473{
1474    struct vm_struct *area;
1475
1476    if (!addr)
1477        return;
1478
1479    if ((PAGE_SIZE-1) & (unsigned long)addr) {
1480        WARN(1, KERN_ERR "Trying to vfree() bad address (%p)\n", addr);
1481        return;
1482    }
1483
1484    area = remove_vm_area(addr);
1485    if (unlikely(!area)) {
1486        WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
1487                addr);
1488        return;
1489    }
1490
1491    debug_check_no_locks_freed(addr, area->size);
1492    debug_check_no_obj_freed(addr, area->size);
1493
1494    if (deallocate_pages) {
1495        int i;
1496
1497        for (i = 0; i < area->nr_pages; i++) {
1498            struct page *page = area->pages[i];
1499
1500            BUG_ON(!page);
1501            __free_page(page);
1502        }
1503
1504        if (area->flags & VM_VPAGES)
1505            vfree(area->pages);
1506        else
1507            kfree(area->pages);
1508    }
1509
1510    kfree(area);
1511    return;
1512}
1513
1514/**
1515 * vfree - release memory allocated by vmalloc()
1516 * @addr: memory base address
1517 *
1518 * Free the virtually continuous memory area starting at @addr, as
1519 * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
1520 * NULL, no operation is performed.
1521 *
1522 * Must not be called in interrupt context.
1523 */
1524void vfree(const void *addr)
1525{
1526    BUG_ON(in_interrupt());
1527
1528    kmemleak_free(addr);
1529
1530    __vunmap(addr, 1);
1531}
1532EXPORT_SYMBOL(vfree);
1533
1534/**
1535 * vunmap - release virtual mapping obtained by vmap()
1536 * @addr: memory base address
1537 *
1538 * Free the virtually contiguous memory area starting at @addr,
1539 * which was created from the page array passed to vmap().
1540 *
1541 * Must not be called in interrupt context.
1542 */
1543void vunmap(const void *addr)
1544{
1545    BUG_ON(in_interrupt());
1546    might_sleep();
1547    __vunmap(addr, 0);
1548}
1549EXPORT_SYMBOL(vunmap);
1550
1551/**
1552 * vmap - map an array of pages into virtually contiguous space
1553 * @pages: array of page pointers
1554 * @count: number of pages to map
1555 * @flags: vm_area->flags
1556 * @prot: page protection for the mapping
1557 *
1558 * Maps @count pages from @pages into contiguous kernel virtual
1559 * space.
1560 */
1561void *vmap(struct page **pages, unsigned int count,
1562        unsigned long flags, pgprot_t prot)
1563{
1564    struct vm_struct *area;
1565
1566    might_sleep();
1567
1568    if (count > totalram_pages)
1569        return NULL;
1570
1571    area = get_vm_area_caller((count << PAGE_SHIFT), flags,
1572                    __builtin_return_address(0));
1573    if (!area)
1574        return NULL;
1575
1576    if (map_vm_area(area, prot, &pages)) {
1577        vunmap(area->addr);
1578        return NULL;
1579    }
1580
1581    return area->addr;
1582}
1583EXPORT_SYMBOL(vmap);
1584
1585static void *__vmalloc_node(unsigned long size, unsigned long align,
1586                gfp_t gfp_mask, pgprot_t prot,
1587                int node, const void *caller);
1588static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
1589                 pgprot_t prot, int node, const void *caller)
1590{
1591    const int order = 0;
1592    struct page **pages;
1593    unsigned int nr_pages, array_size, i;
1594    gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
1595
1596    nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
1597    array_size = (nr_pages * sizeof(struct page *));
1598
1599    area->nr_pages = nr_pages;
1600    /* Please note that the recursion is strictly bounded. */
1601    if (array_size > PAGE_SIZE) {
1602        pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM,
1603                PAGE_KERNEL, node, caller);
1604        area->flags |= VM_VPAGES;
1605    } else {
1606        pages = kmalloc_node(array_size, nested_gfp, node);
1607    }
1608    area->pages = pages;
1609    area->caller = caller;
1610    if (!area->pages) {
1611        remove_vm_area(area->addr);
1612        kfree(area);
1613        return NULL;
1614    }
1615
1616    for (i = 0; i < area->nr_pages; i++) {
1617        struct page *page;
1618        gfp_t tmp_mask = gfp_mask | __GFP_NOWARN;
1619
1620        if (node < 0)
1621            page = alloc_page(tmp_mask);
1622        else
1623            page = alloc_pages_node(node, tmp_mask, order);
1624
1625        if (unlikely(!page)) {
1626            /* Successfully allocated i pages, free them in __vunmap() */
1627            area->nr_pages = i;
1628            goto fail;
1629        }
1630        area->pages[i] = page;
1631    }
1632
1633    if (map_vm_area(area, prot, &pages))
1634        goto fail;
1635    return area->addr;
1636
1637fail:
1638    warn_alloc_failed(gfp_mask, order,
1639              "vmalloc: allocation failure, allocated %ld of %ld bytes\n",
1640              (area->nr_pages*PAGE_SIZE), area->size);
1641    vfree(area->addr);
1642    return NULL;
1643}
1644
1645/**
1646 * __vmalloc_node_range - allocate virtually contiguous memory
1647 * @size: allocation size
1648 * @align: desired alignment
1649 * @start: vm area range start
1650 * @end: vm area range end
1651 * @gfp_mask: flags for the page level allocator
1652 * @prot: protection mask for the allocated pages
1653 * @node: node to use for allocation or -1
1654 * @caller: caller's return address
1655 *
1656 * Allocate enough pages to cover @size from the page level
1657 * allocator with @gfp_mask flags. Map them into contiguous
1658 * kernel virtual space, using a pagetable protection of @prot.
1659 */
1660void *__vmalloc_node_range(unsigned long size, unsigned long align,
1661            unsigned long start, unsigned long end, gfp_t gfp_mask,
1662            pgprot_t prot, int node, const void *caller)
1663{
1664    struct vm_struct *area;
1665    void *addr;
1666    unsigned long real_size = size;
1667
1668    size = PAGE_ALIGN(size);
1669    if (!size || (size >> PAGE_SHIFT) > totalram_pages)
1670        goto fail;
1671
1672    area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST,
1673                  start, end, node, gfp_mask, caller);
1674    if (!area)
1675        goto fail;
1676
1677    addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
1678    if (!addr)
1679        return NULL;
1680
1681    /*
1682     * In this function, newly allocated vm_struct is not added
1683     * to vmlist at __get_vm_area_node(). so, it is added here.
1684     */
1685    insert_vmalloc_vmlist(area);
1686
1687    /*
1688     * A ref_count = 3 is needed because the vm_struct and vmap_area
1689     * structures allocated in the __get_vm_area_node() function contain
1690     * references to the virtual address of the vmalloc'ed block.
1691     */
1692    kmemleak_alloc(addr, real_size, 3, gfp_mask);
1693
1694    return addr;
1695
1696fail:
1697    warn_alloc_failed(gfp_mask, 0,
1698              "vmalloc: allocation failure: %lu bytes\n",
1699              real_size);
1700    return NULL;
1701}
1702
1703/**
1704 * __vmalloc_node - allocate virtually contiguous memory
1705 * @size: allocation size
1706 * @align: desired alignment
1707 * @gfp_mask: flags for the page level allocator
1708 * @prot: protection mask for the allocated pages
1709 * @node: node to use for allocation or -1
1710 * @caller: caller's return address
1711 *
1712 * Allocate enough pages to cover @size from the page level
1713 * allocator with @gfp_mask flags. Map them into contiguous
1714 * kernel virtual space, using a pagetable protection of @prot.
1715 */
1716static void *__vmalloc_node(unsigned long size, unsigned long align,
1717                gfp_t gfp_mask, pgprot_t prot,
1718                int node, const void *caller)
1719{
1720    return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
1721                gfp_mask, prot, node, caller);
1722}
1723
1724void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
1725{
1726    return __vmalloc_node(size, 1, gfp_mask, prot, -1,
1727                __builtin_return_address(0));
1728}
1729EXPORT_SYMBOL(__vmalloc);
1730
1731static inline void *__vmalloc_node_flags(unsigned long size,
1732                    int node, gfp_t flags)
1733{
1734    return __vmalloc_node(size, 1, flags, PAGE_KERNEL,
1735                    node, __builtin_return_address(0));
1736}
1737
1738/**
1739 * vmalloc - allocate virtually contiguous memory
1740 * @size: allocation size
1741 * Allocate enough pages to cover @size from the page level
1742 * allocator and map them into contiguous kernel virtual space.
1743 *
1744 * For tight control over page level allocator and protection flags
1745 * use __vmalloc() instead.
1746 */
1747void *vmalloc(unsigned long size)
1748{
1749    return __vmalloc_node_flags(size, -1, GFP_KERNEL | __GFP_HIGHMEM);
1750}
1751EXPORT_SYMBOL(vmalloc);
1752
1753/**
1754 * vzalloc - allocate virtually contiguous memory with zero fill
1755 * @size: allocation size
1756 * Allocate enough pages to cover @size from the page level
1757 * allocator and map them into contiguous kernel virtual space.
1758 * The memory allocated is set to zero.
1759 *
1760 * For tight control over page level allocator and protection flags
1761 * use __vmalloc() instead.
1762 */
1763void *vzalloc(unsigned long size)
1764{
1765    return __vmalloc_node_flags(size, -1,
1766                GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1767}
1768EXPORT_SYMBOL(vzalloc);
1769
1770/**
1771 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
1772 * @size: allocation size
1773 *
1774 * The resulting memory area is zeroed so it can be mapped to userspace
1775 * without leaking data.
1776 */
1777void *vmalloc_user(unsigned long size)
1778{
1779    struct vm_struct *area;
1780    void *ret;
1781
1782    ret = __vmalloc_node(size, SHMLBA,
1783                 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
1784                 PAGE_KERNEL, -1, __builtin_return_address(0));
1785    if (ret) {
1786        area = find_vm_area(ret);
1787        area->flags |= VM_USERMAP;
1788    }
1789    return ret;
1790}
1791EXPORT_SYMBOL(vmalloc_user);
1792
1793/**
1794 * vmalloc_node - allocate memory on a specific node
1795 * @size: allocation size
1796 * @node: numa node
1797 *
1798 * Allocate enough pages to cover @size from the page level
1799 * allocator and map them into contiguous kernel virtual space.
1800 *
1801 * For tight control over page level allocator and protection flags
1802 * use __vmalloc() instead.
1803 */
1804void *vmalloc_node(unsigned long size, int node)
1805{
1806    return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
1807                    node, __builtin_return_address(0));
1808}
1809EXPORT_SYMBOL(vmalloc_node);
1810
1811/**
1812 * vzalloc_node - allocate memory on a specific node with zero fill
1813 * @size: allocation size
1814 * @node: numa node
1815 *
1816 * Allocate enough pages to cover @size from the page level
1817 * allocator and map them into contiguous kernel virtual space.
1818 * The memory allocated is set to zero.
1819 *
1820 * For tight control over page level allocator and protection flags
1821 * use __vmalloc_node() instead.
1822 */
1823void *vzalloc_node(unsigned long size, int node)
1824{
1825    return __vmalloc_node_flags(size, node,
1826             GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
1827}
1828EXPORT_SYMBOL(vzalloc_node);
1829
1830#ifndef PAGE_KERNEL_EXEC
1831# define PAGE_KERNEL_EXEC PAGE_KERNEL
1832#endif
1833
1834/**
1835 * vmalloc_exec - allocate virtually contiguous, executable memory
1836 * @size: allocation size
1837 *
1838 * Kernel-internal function to allocate enough pages to cover @size
1839 * the page level allocator and map them into contiguous and
1840 * executable kernel virtual space.
1841 *
1842 * For tight control over page level allocator and protection flags
1843 * use __vmalloc() instead.
1844 */
1845
1846void *vmalloc_exec(unsigned long size)
1847{
1848    return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
1849                  -1, __builtin_return_address(0));
1850}
1851
1852#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
1853#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
1854#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
1855#define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
1856#else
1857#define GFP_VMALLOC32 GFP_KERNEL
1858#endif
1859
1860/**
1861 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
1862 * @size: allocation size
1863 *
1864 * Allocate enough 32bit PA addressable pages to cover @size from the
1865 * page level allocator and map them into contiguous kernel virtual space.
1866 */
1867void *vmalloc_32(unsigned long size)
1868{
1869    return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
1870                  -1, __builtin_return_address(0));
1871}
1872EXPORT_SYMBOL(vmalloc_32);
1873
1874/**
1875 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
1876 * @size: allocation size
1877 *
1878 * The resulting memory area is 32bit addressable and zeroed so it can be
1879 * mapped to userspace without leaking data.
1880 */
1881void *vmalloc_32_user(unsigned long size)
1882{
1883    struct vm_struct *area;
1884    void *ret;
1885
1886    ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
1887                 -1, __builtin_return_address(0));
1888    if (ret) {
1889        area = find_vm_area(ret);
1890        area->flags |= VM_USERMAP;
1891    }
1892    return ret;
1893}
1894EXPORT_SYMBOL(vmalloc_32_user);
1895
1896/*
1897 * small helper routine , copy contents to buf from addr.
1898 * If the page is not present, fill zero.
1899 */
1900
1901static int aligned_vread(char *buf, char *addr, unsigned long count)
1902{
1903    struct page *p;
1904    int copied = 0;
1905
1906    while (count) {
1907        unsigned long offset, length;
1908
1909        offset = (unsigned long)addr & ~PAGE_MASK;
1910        length = PAGE_SIZE - offset;
1911        if (length > count)
1912            length = count;
1913        p = vmalloc_to_page(addr);
1914        /*
1915         * To do safe access to this _mapped_ area, we need
1916         * lock. But adding lock here means that we need to add
1917         * overhead of vmalloc()/vfree() calles for this _debug_
1918         * interface, rarely used. Instead of that, we'll use
1919         * kmap() and get small overhead in this access function.
1920         */
1921        if (p) {
1922            /*
1923             * we can expect USER0 is not used (see vread/vwrite's
1924             * function description)
1925             */
1926            void *map = kmap_atomic(p);
1927            memcpy(buf, map + offset, length);
1928            kunmap_atomic(map);
1929        } else
1930            memset(buf, 0, length);
1931
1932        addr += length;
1933        buf += length;
1934        copied += length;
1935        count -= length;
1936    }
1937    return copied;
1938}
1939
1940static int aligned_vwrite(char *buf, char *addr, unsigned long count)
1941{
1942    struct page *p;
1943    int copied = 0;
1944
1945    while (count) {
1946        unsigned long offset, length;
1947
1948        offset = (unsigned long)addr & ~PAGE_MASK;
1949        length = PAGE_SIZE - offset;
1950        if (length > count)
1951            length = count;
1952        p = vmalloc_to_page(addr);
1953        /*
1954         * To do safe access to this _mapped_ area, we need
1955         * lock. But adding lock here means that we need to add
1956         * overhead of vmalloc()/vfree() calles for this _debug_
1957         * interface, rarely used. Instead of that, we'll use
1958         * kmap() and get small overhead in this access function.
1959         */
1960        if (p) {
1961            /*
1962             * we can expect USER0 is not used (see vread/vwrite's
1963             * function description)
1964             */
1965            void *map = kmap_atomic(p);
1966            memcpy(map + offset, buf, length);
1967            kunmap_atomic(map);
1968        }
1969        addr += length;
1970        buf += length;
1971        copied += length;
1972        count -= length;
1973    }
1974    return copied;
1975}
1976
1977/**
1978 * vread() - read vmalloc area in a safe way.
1979 * @buf: buffer for reading data
1980 * @addr: vm address.
1981 * @count: number of bytes to be read.
1982 *
1983 * Returns # of bytes which addr and buf should be increased.
1984 * (same number to @count). Returns 0 if [addr...addr+count) doesn't
1985 * includes any intersect with alive vmalloc area.
1986 *
1987 * This function checks that addr is a valid vmalloc'ed area, and
1988 * copy data from that area to a given buffer. If the given memory range
1989 * of [addr...addr+count) includes some valid address, data is copied to
1990 * proper area of @buf. If there are memory holes, they'll be zero-filled.
1991 * IOREMAP area is treated as memory hole and no copy is done.
1992 *
1993 * If [addr...addr+count) doesn't includes any intersects with alive
1994 * vm_struct area, returns 0. @buf should be kernel's buffer.
1995 *
1996 * Note: In usual ops, vread() is never necessary because the caller
1997 * should know vmalloc() area is valid and can use memcpy().
1998 * This is for routines which have to access vmalloc area without
1999 * any informaion, as /dev/kmem.
2000 *
2001 */
2002
2003long vread(char *buf, char *addr, unsigned long count)
2004{
2005    struct vm_struct *tmp;
2006    char *vaddr, *buf_start = buf;
2007    unsigned long buflen = count;
2008    unsigned long n;
2009
2010    /* Don't allow overflow */
2011    if ((unsigned long) addr + count < count)
2012        count = -(unsigned long) addr;
2013
2014    read_lock(&vmlist_lock);
2015    for (tmp = vmlist; count && tmp; tmp = tmp->next) {
2016        vaddr = (char *) tmp->addr;
2017        if (addr >= vaddr + tmp->size - PAGE_SIZE)
2018            continue;
2019        while (addr < vaddr) {
2020            if (count == 0)
2021                goto finished;
2022            *buf = '\0';
2023            buf++;
2024            addr++;
2025            count--;
2026        }
2027        n = vaddr + tmp->size - PAGE_SIZE - addr;
2028        if (n > count)
2029            n = count;
2030        if (!(tmp->flags & VM_IOREMAP))
2031            aligned_vread(buf, addr, n);
2032        else /* IOREMAP area is treated as memory hole */
2033            memset(buf, 0, n);
2034        buf += n;
2035        addr += n;
2036        count -= n;
2037    }
2038finished:
2039    read_unlock(&vmlist_lock);
2040
2041    if (buf == buf_start)
2042        return 0;
2043    /* zero-fill memory holes */
2044    if (buf != buf_start + buflen)
2045        memset(buf, 0, buflen - (buf - buf_start));
2046
2047    return buflen;
2048}
2049
2050/**
2051 * vwrite() - write vmalloc area in a safe way.
2052 * @buf: buffer for source data
2053 * @addr: vm address.
2054 * @count: number of bytes to be read.
2055 *
2056 * Returns # of bytes which addr and buf should be incresed.
2057 * (same number to @count).
2058 * If [addr...addr+count) doesn't includes any intersect with valid
2059 * vmalloc area, returns 0.
2060 *
2061 * This function checks that addr is a valid vmalloc'ed area, and
2062 * copy data from a buffer to the given addr. If specified range of
2063 * [addr...addr+count) includes some valid address, data is copied from
2064 * proper area of @buf. If there are memory holes, no copy to hole.
2065 * IOREMAP area is treated as memory hole and no copy is done.
2066 *
2067 * If [addr...addr+count) doesn't includes any intersects with alive
2068 * vm_struct area, returns 0. @buf should be kernel's buffer.
2069 *
2070 * Note: In usual ops, vwrite() is never necessary because the caller
2071 * should know vmalloc() area is valid and can use memcpy().
2072 * This is for routines which have to access vmalloc area without
2073 * any informaion, as /dev/kmem.
2074 */
2075
2076long vwrite(char *buf, char *addr, unsigned long count)
2077{
2078    struct vm_struct *tmp;
2079    char *vaddr;
2080    unsigned long n, buflen;
2081    int copied = 0;
2082
2083    /* Don't allow overflow */
2084    if ((unsigned long) addr + count < count)
2085        count = -(unsigned long) addr;
2086    buflen = count;
2087
2088    read_lock(&vmlist_lock);
2089    for (tmp = vmlist; count && tmp; tmp = tmp->next) {
2090        vaddr = (char *) tmp->addr;
2091        if (addr >= vaddr + tmp->size - PAGE_SIZE)
2092            continue;
2093        while (addr < vaddr) {
2094            if (count == 0)
2095                goto finished;
2096            buf++;
2097            addr++;
2098            count--;
2099        }
2100        n = vaddr + tmp->size - PAGE_SIZE - addr;
2101        if (n > count)
2102            n = count;
2103        if (!(tmp->flags & VM_IOREMAP)) {
2104            aligned_vwrite(buf, addr, n);
2105            copied++;
2106        }
2107        buf += n;
2108        addr += n;
2109        count -= n;
2110    }
2111finished:
2112    read_unlock(&vmlist_lock);
2113    if (!copied)
2114        return 0;
2115    return buflen;
2116}
2117
2118/**
2119 * remap_vmalloc_range - map vmalloc pages to userspace
2120 * @vma: vma to cover (map full range of vma)
2121 * @addr: vmalloc memory
2122 * @pgoff: number of pages into addr before first page to map
2123 *
2124 * Returns: 0 for success, -Exxx on failure
2125 *
2126 * This function checks that addr is a valid vmalloc'ed area, and
2127 * that it is big enough to cover the vma. Will return failure if
2128 * that criteria isn't met.
2129 *
2130 * Similar to remap_pfn_range() (see mm/memory.c)
2131 */
2132int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
2133                        unsigned long pgoff)
2134{
2135    struct vm_struct *area;
2136    unsigned long uaddr = vma->vm_start;
2137    unsigned long usize = vma->vm_end - vma->vm_start;
2138
2139    if ((PAGE_SIZE-1) & (unsigned long)addr)
2140        return -EINVAL;
2141
2142    area = find_vm_area(addr);
2143    if (!area)
2144        return -EINVAL;
2145
2146    if (!(area->flags & VM_USERMAP))
2147        return -EINVAL;
2148
2149    if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
2150        return -EINVAL;
2151
2152    addr += pgoff << PAGE_SHIFT;
2153    do {
2154        struct page *page = vmalloc_to_page(addr);
2155        int ret;
2156
2157        ret = vm_insert_page(vma, uaddr, page);
2158        if (ret)
2159            return ret;
2160
2161        uaddr += PAGE_SIZE;
2162        addr += PAGE_SIZE;
2163        usize -= PAGE_SIZE;
2164    } while (usize > 0);
2165
2166    /* Prevent "things" like memory migration? VM_flags need a cleanup... */
2167    vma->vm_flags |= VM_RESERVED;
2168
2169    return 0;
2170}
2171EXPORT_SYMBOL(remap_vmalloc_range);
2172
2173/*
2174 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
2175 * have one.
2176 */
2177void __attribute__((weak)) vmalloc_sync_all(void)
2178{
2179}
2180
2181
2182static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
2183{
2184    pte_t ***p = data;
2185
2186    if (p) {
2187        *(*p) = pte;
2188        (*p)++;
2189    }
2190    return 0;
2191}
2192
2193/**
2194 * alloc_vm_area - allocate a range of kernel address space
2195 * @size: size of the area
2196 * @ptes: returns the PTEs for the address space
2197 *
2198 * Returns: NULL on failure, vm_struct on success
2199 *
2200 * This function reserves a range of kernel address space, and
2201 * allocates pagetables to map that range. No actual mappings
2202 * are created.
2203 *
2204 * If @ptes is non-NULL, pointers to the PTEs (in init_mm)
2205 * allocated for the VM area are returned.
2206 */
2207struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
2208{
2209    struct vm_struct *area;
2210
2211    area = get_vm_area_caller(size, VM_IOREMAP,
2212                __builtin_return_address(0));
2213    if (area == NULL)
2214        return NULL;
2215
2216    /*
2217     * This ensures that page tables are constructed for this region
2218     * of kernel virtual address space and mapped into init_mm.
2219     */
2220    if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
2221                size, f, ptes ? &ptes : NULL)) {
2222        free_vm_area(area);
2223        return NULL;
2224    }
2225
2226    return area;
2227}
2228EXPORT_SYMBOL_GPL(alloc_vm_area);
2229
2230void free_vm_area(struct vm_struct *area)
2231{
2232    struct vm_struct *ret;
2233    ret = remove_vm_area(area->addr);
2234    BUG_ON(ret != area);
2235    kfree(area);
2236}
2237EXPORT_SYMBOL_GPL(free_vm_area);
2238
2239#ifdef CONFIG_SMP
2240static struct vmap_area *node_to_va(struct rb_node *n)
2241{
2242    return n ? rb_entry(n, struct vmap_area, rb_node) : NULL;
2243}
2244
2245/**
2246 * pvm_find_next_prev - find the next and prev vmap_area surrounding @end
2247 * @end: target address
2248 * @pnext: out arg for the next vmap_area
2249 * @pprev: out arg for the previous vmap_area
2250 *
2251 * Returns: %true if either or both of next and prev are found,
2252 * %false if no vmap_area exists
2253 *
2254 * Find vmap_areas end addresses of which enclose @end. ie. if not
2255 * NULL, *pnext->va_end > @end and *pprev->va_end <= @end.
2256 */
2257static bool pvm_find_next_prev(unsigned long end,
2258                   struct vmap_area **pnext,
2259                   struct vmap_area **pprev)
2260{
2261    struct rb_node *n = vmap_area_root.rb_node;
2262    struct vmap_area *va = NULL;
2263
2264    while (n) {
2265        va = rb_entry(n, struct vmap_area, rb_node);
2266        if (end < va->va_end)
2267            n = n->rb_left;
2268        else if (end > va->va_end)
2269            n = n->rb_right;
2270        else
2271            break;
2272    }
2273
2274    if (!va)
2275        return false;
2276
2277    if (va->va_end > end) {
2278        *pnext = va;
2279        *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2280    } else {
2281        *pprev = va;
2282        *pnext = node_to_va(rb_next(&(*pprev)->rb_node));
2283    }
2284    return true;
2285}
2286
2287/**
2288 * pvm_determine_end - find the highest aligned address between two vmap_areas
2289 * @pnext: in/out arg for the next vmap_area
2290 * @pprev: in/out arg for the previous vmap_area
2291 * @align: alignment
2292 *
2293 * Returns: determined end address
2294 *
2295 * Find the highest aligned address between *@pnext and *@pprev below
2296 * VMALLOC_END. *@pnext and *@pprev are adjusted so that the aligned
2297 * down address is between the end addresses of the two vmap_areas.
2298 *
2299 * Please note that the address returned by this function may fall
2300 * inside *@pnext vmap_area. The caller is responsible for checking
2301 * that.
2302 */
2303static unsigned long pvm_determine_end(struct vmap_area **pnext,
2304                       struct vmap_area **pprev,
2305                       unsigned long align)
2306{
2307    const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2308    unsigned long addr;
2309
2310    if (*pnext)
2311        addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end);
2312    else
2313        addr = vmalloc_end;
2314
2315    while (*pprev && (*pprev)->va_end > addr) {
2316        *pnext = *pprev;
2317        *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2318    }
2319
2320    return addr;
2321}
2322
2323/**
2324 * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
2325 * @offsets: array containing offset of each area
2326 * @sizes: array containing size of each area
2327 * @nr_vms: the number of areas to allocate
2328 * @align: alignment, all entries in @offsets and @sizes must be aligned to this
2329 *
2330 * Returns: kmalloc'd vm_struct pointer array pointing to allocated
2331 * vm_structs on success, %NULL on failure
2332 *
2333 * Percpu allocator wants to use congruent vm areas so that it can
2334 * maintain the offsets among percpu areas. This function allocates
2335 * congruent vmalloc areas for it with GFP_KERNEL. These areas tend to
2336 * be scattered pretty far, distance between two areas easily going up
2337 * to gigabytes. To avoid interacting with regular vmallocs, these
2338 * areas are allocated from top.
2339 *
2340 * Despite its complicated look, this allocator is rather simple. It
2341 * does everything top-down and scans areas from the end looking for
2342 * matching slot. While scanning, if any of the areas overlaps with
2343 * existing vmap_area, the base address is pulled down to fit the
2344 * area. Scanning is repeated till all the areas fit and then all
2345 * necessary data structres are inserted and the result is returned.
2346 */
2347struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
2348                     const size_t *sizes, int nr_vms,
2349                     size_t align)
2350{
2351    const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
2352    const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2353    struct vmap_area **vas, *prev, *next;
2354    struct vm_struct **vms;
2355    int area, area2, last_area, term_area;
2356    unsigned long base, start, end, last_end;
2357    bool purged = false;
2358
2359    /* verify parameters and allocate data structures */
2360    BUG_ON(align & ~PAGE_MASK || !is_power_of_2(align));
2361    for (last_area = 0, area = 0; area < nr_vms; area++) {
2362        start = offsets[area];
2363        end = start + sizes[area];
2364
2365        /* is everything aligned properly? */
2366        BUG_ON(!IS_ALIGNED(offsets[area], align));
2367        BUG_ON(!IS_ALIGNED(sizes[area], align));
2368
2369        /* detect the area with the highest address */
2370        if (start > offsets[last_area])
2371            last_area = area;
2372
2373        for (area2 = 0; area2 < nr_vms; area2++) {
2374            unsigned long start2 = offsets[area2];
2375            unsigned long end2 = start2 + sizes[area2];
2376
2377            if (area2 == area)
2378                continue;
2379
2380            BUG_ON(start2 >= start && start2 < end);
2381            BUG_ON(end2 <= end && end2 > start);
2382        }
2383    }
2384    last_end = offsets[last_area] + sizes[last_area];
2385
2386    if (vmalloc_end - vmalloc_start < last_end) {
2387        WARN_ON(true);
2388        return NULL;
2389    }
2390
2391    vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL);
2392    vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL);
2393    if (!vas || !vms)
2394        goto err_free2;
2395
2396    for (area = 0; area < nr_vms; area++) {
2397        vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL);
2398        vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL);
2399        if (!vas[area] || !vms[area])
2400            goto err_free;
2401    }
2402retry:
2403    spin_lock(&vmap_area_lock);
2404
2405    /* start scanning - we scan from the top, begin with the last area */
2406    area = term_area = last_area;
2407    start = offsets[area];
2408    end = start + sizes[area];
2409
2410    if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) {
2411        base = vmalloc_end - last_end;
2412        goto found;
2413    }
2414    base = pvm_determine_end(&next, &prev, align) - end;
2415
2416    while (true) {
2417        BUG_ON(next && next->va_end <= base + end);
2418        BUG_ON(prev && prev->va_end > base + end);
2419
2420        /*
2421         * base might have underflowed, add last_end before
2422         * comparing.
2423         */
2424        if (base + last_end < vmalloc_start + last_end) {
2425            spin_unlock(&vmap_area_lock);
2426            if (!purged) {
2427                purge_vmap_area_lazy();
2428                purged = true;
2429                goto retry;
2430            }
2431            goto err_free;
2432        }
2433
2434        /*
2435         * If next overlaps, move base downwards so that it's
2436         * right below next and then recheck.
2437         */
2438        if (next && next->va_start < base + end) {
2439            base = pvm_determine_end(&next, &prev, align) - end;
2440            term_area = area;
2441            continue;
2442        }
2443
2444        /*
2445         * If prev overlaps, shift down next and prev and move
2446         * base so that it's right below new next and then
2447         * recheck.
2448         */
2449        if (prev && prev->va_end > base + start) {
2450            next = prev;
2451            prev = node_to_va(rb_prev(&next->rb_node));
2452            base = pvm_determine_end(&next, &prev, align) - end;
2453            term_area = area;
2454            continue;
2455        }
2456
2457        /*
2458         * This area fits, move on to the previous one. If
2459         * the previous one is the terminal one, we're done.
2460         */
2461        area = (area + nr_vms - 1) % nr_vms;
2462        if (area == term_area)
2463            break;
2464        start = offsets[area];
2465        end = start + sizes[area];
2466        pvm_find_next_prev(base + end, &next, &prev);
2467    }
2468found:
2469    /* we've found a fitting base, insert all va's */
2470    for (area = 0; area < nr_vms; area++) {
2471        struct vmap_area *va = vas[area];
2472
2473        va->va_start = base + offsets[area];
2474        va->va_end = va->va_start + sizes[area];
2475        __insert_vmap_area(va);
2476    }
2477
2478    vmap_area_pcpu_hole = base + offsets[last_area];
2479
2480    spin_unlock(&vmap_area_lock);
2481
2482    /* insert all vm's */
2483    for (area = 0; area < nr_vms; area++)
2484        insert_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
2485                  pcpu_get_vm_areas);
2486
2487    kfree(vas);
2488    return vms;
2489
2490err_free:
2491    for (area = 0; area < nr_vms; area++) {
2492        kfree(vas[area]);
2493        kfree(vms[area]);
2494    }
2495err_free2:
2496    kfree(vas);
2497    kfree(vms);
2498    return NULL;
2499}
2500
2501/**
2502 * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
2503 * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
2504 * @nr_vms: the number of allocated areas
2505 *
2506 * Free vm_structs and the array allocated by pcpu_get_vm_areas().
2507 */
2508void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
2509{
2510    int i;
2511
2512    for (i = 0; i < nr_vms; i++)
2513        free_vm_area(vms[i]);
2514    kfree(vms);
2515}
2516#endif /* CONFIG_SMP */
2517
2518#ifdef CONFIG_PROC_FS
2519static void *s_start(struct seq_file *m, loff_t *pos)
2520    __acquires(&vmlist_lock)
2521{
2522    loff_t n = *pos;
2523    struct vm_struct *v;
2524
2525    read_lock(&vmlist_lock);
2526    v = vmlist;
2527    while (n > 0 && v) {
2528        n--;
2529        v = v->next;
2530    }
2531    if (!n)
2532        return v;
2533
2534    return NULL;
2535
2536}
2537
2538static void *s_next(struct seq_file *m, void *p, loff_t *pos)
2539{
2540    struct vm_struct *v = p;
2541
2542    ++*pos;
2543    return v->next;
2544}
2545
2546static void s_stop(struct seq_file *m, void *p)
2547    __releases(&vmlist_lock)
2548{
2549    read_unlock(&vmlist_lock);
2550}
2551
2552static void show_numa_info(struct seq_file *m, struct vm_struct *v)
2553{
2554    if (NUMA_BUILD) {
2555        unsigned int nr, *counters = m->private;
2556
2557        if (!counters)
2558            return;
2559
2560        memset(counters, 0, nr_node_ids * sizeof(unsigned int));
2561
2562        for (nr = 0; nr < v->nr_pages; nr++)
2563            counters[page_to_nid(v->pages[nr])]++;
2564
2565        for_each_node_state(nr, N_HIGH_MEMORY)
2566            if (counters[nr])
2567                seq_printf(m, " N%u=%u", nr, counters[nr]);
2568    }
2569}
2570
2571static int s_show(struct seq_file *m, void *p)
2572{
2573    struct vm_struct *v = p;
2574
2575    seq_printf(m, "0x%p-0x%p %7ld",
2576        v->addr, v->addr + v->size, v->size);
2577
2578    if (v->caller)
2579        seq_printf(m, " %pS", v->caller);
2580
2581    if (v->nr_pages)
2582        seq_printf(m, " pages=%d", v->nr_pages);
2583
2584    if (v->phys_addr)
2585        seq_printf(m, " phys=%llx", (unsigned long long)v->phys_addr);
2586
2587    if (v->flags & VM_IOREMAP)
2588        seq_printf(m, " ioremap");
2589
2590    if (v->flags & VM_ALLOC)
2591        seq_printf(m, " vmalloc");
2592
2593    if (v->flags & VM_MAP)
2594        seq_printf(m, " vmap");
2595
2596    if (v->flags & VM_USERMAP)
2597        seq_printf(m, " user");
2598
2599    if (v->flags & VM_VPAGES)
2600        seq_printf(m, " vpages");
2601
2602    show_numa_info(m, v);
2603    seq_putc(m, '\n');
2604    return 0;
2605}
2606
2607static const struct seq_operations vmalloc_op = {
2608    .start = s_start,
2609    .next = s_next,
2610    .stop = s_stop,
2611    .show = s_show,
2612};
2613
2614static int vmalloc_open(struct inode *inode, struct file *file)
2615{
2616    unsigned int *ptr = NULL;
2617    int ret;
2618
2619    if (NUMA_BUILD) {
2620        ptr = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL);
2621        if (ptr == NULL)
2622            return -ENOMEM;
2623    }
2624    ret = seq_open(file, &vmalloc_op);
2625    if (!ret) {
2626        struct seq_file *m = file->private_data;
2627        m->private = ptr;
2628    } else
2629        kfree(ptr);
2630    return ret;
2631}
2632
2633static const struct file_operations proc_vmalloc_operations = {
2634    .open = vmalloc_open,
2635    .read = seq_read,
2636    .llseek = seq_lseek,
2637    .release = seq_release_private,
2638};
2639
2640static int __init proc_vmalloc_init(void)
2641{
2642    proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
2643    return 0;
2644}
2645module_init(proc_vmalloc_init);
2646#endif
2647
2648

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