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TOMOYO Linux Cross Reference
Linux/mm/vmalloc.c

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  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 <asm/atomic.h>
 30 #include <asm/uaccess.h>
 31 #include <asm/tlbflush.h>
 32 #include <asm/shmparam.h>
 33 
 34 
 35 /*** Page table manipulation functions ***/
 36 
 37 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
 38 {
 39         pte_t *pte;
 40 
 41         pte = pte_offset_kernel(pmd, addr);
 42         do {
 43                 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
 44                 WARN_ON(!pte_none(ptent) && !pte_present(ptent));
 45         } while (pte++, addr += PAGE_SIZE, addr != end);
 46 }
 47 
 48 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
 49 {
 50         pmd_t *pmd;
 51         unsigned long next;
 52 
 53         pmd = pmd_offset(pud, addr);
 54         do {
 55                 next = pmd_addr_end(addr, end);
 56                 if (pmd_none_or_clear_bad(pmd))
 57                         continue;
 58                 vunmap_pte_range(pmd, addr, next);
 59         } while (pmd++, addr = next, addr != end);
 60 }
 61 
 62 static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end)
 63 {
 64         pud_t *pud;
 65         unsigned long next;
 66 
 67         pud = pud_offset(pgd, addr);
 68         do {
 69                 next = pud_addr_end(addr, end);
 70                 if (pud_none_or_clear_bad(pud))
 71                         continue;
 72                 vunmap_pmd_range(pud, addr, next);
 73         } while (pud++, addr = next, addr != end);
 74 }
 75 
 76 static void vunmap_page_range(unsigned long addr, unsigned long end)
 77 {
 78         pgd_t *pgd;
 79         unsigned long next;
 80 
 81         BUG_ON(addr >= end);
 82         pgd = pgd_offset_k(addr);
 83         do {
 84                 next = pgd_addr_end(addr, end);
 85                 if (pgd_none_or_clear_bad(pgd))
 86                         continue;
 87                 vunmap_pud_range(pgd, addr, next);
 88         } while (pgd++, addr = next, addr != end);
 89 }
 90 
 91 static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
 92                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
 93 {
 94         pte_t *pte;
 95 
 96         /*
 97          * nr is a running index into the array which helps higher level
 98          * callers keep track of where we're up to.
 99          */
100 
101         pte = pte_alloc_kernel(pmd, addr);
102         if (!pte)
103                 return -ENOMEM;
104         do {
105                 struct page *page = pages[*nr];
106 
107                 if (WARN_ON(!pte_none(*pte)))
108                         return -EBUSY;
109                 if (WARN_ON(!page))
110                         return -ENOMEM;
111                 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
112                 (*nr)++;
113         } while (pte++, addr += PAGE_SIZE, addr != end);
114         return 0;
115 }
116 
117 static int vmap_pmd_range(pud_t *pud, unsigned long addr,
118                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
119 {
120         pmd_t *pmd;
121         unsigned long next;
122 
123         pmd = pmd_alloc(&init_mm, pud, addr);
124         if (!pmd)
125                 return -ENOMEM;
126         do {
127                 next = pmd_addr_end(addr, end);
128                 if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
129                         return -ENOMEM;
130         } while (pmd++, addr = next, addr != end);
131         return 0;
132 }
133 
134 static int vmap_pud_range(pgd_t *pgd, unsigned long addr,
135                 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
136 {
137         pud_t *pud;
138         unsigned long next;
139 
140         pud = pud_alloc(&init_mm, pgd, addr);
141         if (!pud)
142                 return -ENOMEM;
143         do {
144                 next = pud_addr_end(addr, end);
145                 if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
146                         return -ENOMEM;
147         } while (pud++, addr = next, addr != end);
148         return 0;
149 }
150 
151 /*
152  * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and
153  * will have pfns corresponding to the "pages" array.
154  *
155  * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N]
156  */
157 static int vmap_page_range_noflush(unsigned long start, unsigned long end,
158                                    pgprot_t prot, struct page **pages)
159 {
160         pgd_t *pgd;
161         unsigned long next;
162         unsigned long addr = start;
163         int err = 0;
164         int nr = 0;
165 
166         BUG_ON(addr >= end);
167         pgd = pgd_offset_k(addr);
168         do {
169                 next = pgd_addr_end(addr, end);
170                 err = vmap_pud_range(pgd, addr, next, prot, pages, &nr);
171                 if (err)
172                         return err;
173         } while (pgd++, addr = next, addr != end);
174 
175         return nr;
176 }
177 
178 static int vmap_page_range(unsigned long start, unsigned long end,
179                            pgprot_t prot, struct page **pages)
180 {
181         int ret;
182 
183         ret = vmap_page_range_noflush(start, end, prot, pages);
184         flush_cache_vmap(start, end);
185         return ret;
186 }
187 
188 int is_vmalloc_or_module_addr(const void *x)
189 {
190         /*
191          * ARM, x86-64 and sparc64 put modules in a special place,
192          * and fall back on vmalloc() if that fails. Others
193          * just put it in the vmalloc space.
194          */
195 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
196         unsigned long addr = (unsigned long)x;
197         if (addr >= MODULES_VADDR && addr < MODULES_END)
198                 return 1;
199 #endif
200         return is_vmalloc_addr(x);
201 }
202 
203 /*
204  * Walk a vmap address to the struct page it maps.
205  */
206 struct page *vmalloc_to_page(const void *vmalloc_addr)
207 {
208         unsigned long addr = (unsigned long) vmalloc_addr;
209         struct page *page = NULL;
210         pgd_t *pgd = pgd_offset_k(addr);
211 
212         /*
213          * XXX we might need to change this if we add VIRTUAL_BUG_ON for
214          * architectures that do not vmalloc module space
215          */
216         VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
217 
218         if (!pgd_none(*pgd)) {
219                 pud_t *pud = pud_offset(pgd, addr);
220                 if (!pud_none(*pud)) {
221                         pmd_t *pmd = pmd_offset(pud, addr);
222                         if (!pmd_none(*pmd)) {
223                                 pte_t *ptep, pte;
224 
225                                 ptep = pte_offset_map(pmd, addr);
226                                 pte = *ptep;
227                                 if (pte_present(pte))
228                                         page = pte_page(pte);
229                                 pte_unmap(ptep);
230                         }
231                 }
232         }
233         return page;
234 }
235 EXPORT_SYMBOL(vmalloc_to_page);
236 
237 /*
238  * Map a vmalloc()-space virtual address to the physical page frame number.
239  */
240 unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
241 {
242         return page_to_pfn(vmalloc_to_page(vmalloc_addr));
243 }
244 EXPORT_SYMBOL(vmalloc_to_pfn);
245 
246 
247 /*** Global kva allocator ***/
248 
249 #define VM_LAZY_FREE    0x01
250 #define VM_LAZY_FREEING 0x02
251 #define VM_VM_AREA      0x04
252 
253 struct vmap_area {
254         unsigned long va_start;
255         unsigned long va_end;
256         unsigned long flags;
257         struct rb_node rb_node;         /* address sorted rbtree */
258         struct list_head list;          /* address sorted list */
259         struct list_head purge_list;    /* "lazy purge" list */
260         void *private;
261         struct rcu_head rcu_head;
262 };
263 
264 static DEFINE_SPINLOCK(vmap_area_lock);
265 static struct rb_root vmap_area_root = RB_ROOT;
266 static LIST_HEAD(vmap_area_list);
267 static unsigned long vmap_area_pcpu_hole;
268 
269 static struct vmap_area *__find_vmap_area(unsigned long addr)
270 {
271         struct rb_node *n = vmap_area_root.rb_node;
272 
273         while (n) {
274                 struct vmap_area *va;
275 
276                 va = rb_entry(n, struct vmap_area, rb_node);
277                 if (addr < va->va_start)
278                         n = n->rb_left;
279                 else if (addr > va->va_start)
280                         n = n->rb_right;
281                 else
282                         return va;
283         }
284 
285         return NULL;
286 }
287 
288 static void __insert_vmap_area(struct vmap_area *va)
289 {
290         struct rb_node **p = &vmap_area_root.rb_node;
291         struct rb_node *parent = NULL;
292         struct rb_node *tmp;
293 
294         while (*p) {
295                 struct vmap_area *tmp;
296 
297                 parent = *p;
298                 tmp = rb_entry(parent, struct vmap_area, rb_node);
299                 if (va->va_start < tmp->va_end)
300                         p = &(*p)->rb_left;
301                 else if (va->va_end > tmp->va_start)
302                         p = &(*p)->rb_right;
303                 else
304                         BUG();
305         }
306 
307         rb_link_node(&va->rb_node, parent, p);
308         rb_insert_color(&va->rb_node, &vmap_area_root);
309 
310         /* address-sort this list so it is usable like the vmlist */
311         tmp = rb_prev(&va->rb_node);
312         if (tmp) {
313                 struct vmap_area *prev;
314                 prev = rb_entry(tmp, struct vmap_area, rb_node);
315                 list_add_rcu(&va->list, &prev->list);
316         } else
317                 list_add_rcu(&va->list, &vmap_area_list);
318 }
319 
320 static void purge_vmap_area_lazy(void);
321 
322 /*
323  * Allocate a region of KVA of the specified size and alignment, within the
324  * vstart and vend.
325  */
326 static struct vmap_area *alloc_vmap_area(unsigned long size,
327                                 unsigned long align,
328                                 unsigned long vstart, unsigned long vend,
329                                 int node, gfp_t gfp_mask)
330 {
331         struct vmap_area *va;
332         struct rb_node *n;
333         unsigned long addr;
334         int purged = 0;
335 
336         BUG_ON(!size);
337         BUG_ON(size & ~PAGE_MASK);
338 
339         va = kmalloc_node(sizeof(struct vmap_area),
340                         gfp_mask & GFP_RECLAIM_MASK, node);
341         if (unlikely(!va))
342                 return ERR_PTR(-ENOMEM);
343 
344 retry:
345         addr = ALIGN(vstart, align);
346 
347         spin_lock(&vmap_area_lock);
348         if (addr + size - 1 < addr)
349                 goto overflow;
350 
351         /* XXX: could have a last_hole cache */
352         n = vmap_area_root.rb_node;
353         if (n) {
354                 struct vmap_area *first = NULL;
355 
356                 do {
357                         struct vmap_area *tmp;
358                         tmp = rb_entry(n, struct vmap_area, rb_node);
359                         if (tmp->va_end >= addr) {
360                                 if (!first && tmp->va_start < addr + size)
361                                         first = tmp;
362                                 n = n->rb_left;
363                         } else {
364                                 first = tmp;
365                                 n = n->rb_right;
366                         }
367                 } while (n);
368 
369                 if (!first)
370                         goto found;
371 
372                 if (first->va_end < addr) {
373                         n = rb_next(&first->rb_node);
374                         if (n)
375                                 first = rb_entry(n, struct vmap_area, rb_node);
376                         else
377                                 goto found;
378                 }
379 
380                 while (addr + size > first->va_start && addr + size <= vend) {
381                         addr = ALIGN(first->va_end + PAGE_SIZE, align);
382                         if (addr + size - 1 < addr)
383                                 goto overflow;
384 
385                         n = rb_next(&first->rb_node);
386                         if (n)
387                                 first = rb_entry(n, struct vmap_area, rb_node);
388                         else
389                                 goto found;
390                 }
391         }
392 found:
393         if (addr + size > vend) {
394 overflow:
395                 spin_unlock(&vmap_area_lock);
396                 if (!purged) {
397                         purge_vmap_area_lazy();
398                         purged = 1;
399                         goto retry;
400                 }
401                 if (printk_ratelimit())
402                         printk(KERN_WARNING
403                                 "vmap allocation for size %lu failed: "
404                                 "use vmalloc=<size> to increase size.\n", size);
405                 kfree(va);
406                 return ERR_PTR(-EBUSY);
407         }
408 
409         BUG_ON(addr & (align-1));
410 
411         va->va_start = addr;
412         va->va_end = addr + size;
413         va->flags = 0;
414         __insert_vmap_area(va);
415         spin_unlock(&vmap_area_lock);
416 
417         return va;
418 }
419 
420 static void rcu_free_va(struct rcu_head *head)
421 {
422         struct vmap_area *va = container_of(head, struct vmap_area, rcu_head);
423 
424         kfree(va);
425 }
426 
427 static void __free_vmap_area(struct vmap_area *va)
428 {
429         BUG_ON(RB_EMPTY_NODE(&va->rb_node));
430         rb_erase(&va->rb_node, &vmap_area_root);
431         RB_CLEAR_NODE(&va->rb_node);
432         list_del_rcu(&va->list);
433 
434         /*
435          * Track the highest possible candidate for pcpu area
436          * allocation.  Areas outside of vmalloc area can be returned
437          * here too, consider only end addresses which fall inside
438          * vmalloc area proper.
439          */
440         if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
441                 vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);
442 
443         call_rcu(&va->rcu_head, rcu_free_va);
444 }
445 
446 /*
447  * Free a region of KVA allocated by alloc_vmap_area
448  */
449 static void free_vmap_area(struct vmap_area *va)
450 {
451         spin_lock(&vmap_area_lock);
452         __free_vmap_area(va);
453         spin_unlock(&vmap_area_lock);
454 }
455 
456 /*
457  * Clear the pagetable entries of a given vmap_area
458  */
459 static void unmap_vmap_area(struct vmap_area *va)
460 {
461         vunmap_page_range(va->va_start, va->va_end);
462 }
463 
464 static void vmap_debug_free_range(unsigned long start, unsigned long end)
465 {
466         /*
467          * Unmap page tables and force a TLB flush immediately if
468          * CONFIG_DEBUG_PAGEALLOC is set. This catches use after free
469          * bugs similarly to those in linear kernel virtual address
470          * space after a page has been freed.
471          *
472          * All the lazy freeing logic is still retained, in order to
473          * minimise intrusiveness of this debugging feature.
474          *
475          * This is going to be *slow* (linear kernel virtual address
476          * debugging doesn't do a broadcast TLB flush so it is a lot
477          * faster).
478          */
479 #ifdef CONFIG_DEBUG_PAGEALLOC
480         vunmap_page_range(start, end);
481         flush_tlb_kernel_range(start, end);
482 #endif
483 }
484 
485 /*
486  * lazy_max_pages is the maximum amount of virtual address space we gather up
487  * before attempting to purge with a TLB flush.
488  *
489  * There is a tradeoff here: a larger number will cover more kernel page tables
490  * and take slightly longer to purge, but it will linearly reduce the number of
491  * global TLB flushes that must be performed. It would seem natural to scale
492  * this number up linearly with the number of CPUs (because vmapping activity
493  * could also scale linearly with the number of CPUs), however it is likely
494  * that in practice, workloads might be constrained in other ways that mean
495  * vmap activity will not scale linearly with CPUs. Also, I want to be
496  * conservative and not introduce a big latency on huge systems, so go with
497  * a less aggressive log scale. It will still be an improvement over the old
498  * code, and it will be simple to change the scale factor if we find that it
499  * becomes a problem on bigger systems.
500  */
501 static unsigned long lazy_max_pages(void)
502 {
503         unsigned int log;
504 
505         log = fls(num_online_cpus());
506 
507         return log * (32UL * 1024 * 1024 / PAGE_SIZE);
508 }
509 
510 static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
511 
512 /* for per-CPU blocks */
513 static void purge_fragmented_blocks_allcpus(void);
514 
515 /*
516  * called before a call to iounmap() if the caller wants vm_area_struct's
517  * immediately freed.
518  */
519 void set_iounmap_nonlazy(void)
520 {
521         atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
522 }
523 
524 /*
525  * Purges all lazily-freed vmap areas.
526  *
527  * If sync is 0 then don't purge if there is already a purge in progress.
528  * If force_flush is 1, then flush kernel TLBs between *start and *end even
529  * if we found no lazy vmap areas to unmap (callers can use this to optimise
530  * their own TLB flushing).
531  * Returns with *start = min(*start, lowest purged address)
532  *              *end = max(*end, highest purged address)
533  */
534 static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
535                                         int sync, int force_flush)
536 {
537         static DEFINE_SPINLOCK(purge_lock);
538         LIST_HEAD(valist);
539         struct vmap_area *va;
540         struct vmap_area *n_va;
541         int nr = 0;
542 
543         /*
544          * If sync is 0 but force_flush is 1, we'll go sync anyway but callers
545          * should not expect such behaviour. This just simplifies locking for
546          * the case that isn't actually used at the moment anyway.
547          */
548         if (!sync && !force_flush) {
549                 if (!spin_trylock(&purge_lock))
550                         return;
551         } else
552                 spin_lock(&purge_lock);
553 
554         if (sync)
555                 purge_fragmented_blocks_allcpus();
556 
557         rcu_read_lock();
558         list_for_each_entry_rcu(va, &vmap_area_list, list) {
559                 if (va->flags & VM_LAZY_FREE) {
560                         if (va->va_start < *start)
561                                 *start = va->va_start;
562                         if (va->va_end > *end)
563                                 *end = va->va_end;
564                         nr += (va->va_end - va->va_start) >> PAGE_SHIFT;
565                         unmap_vmap_area(va);
566                         list_add_tail(&va->purge_list, &valist);
567                         va->flags |= VM_LAZY_FREEING;
568                         va->flags &= ~VM_LAZY_FREE;
569                 }
570         }
571         rcu_read_unlock();
572 
573         if (nr)
574                 atomic_sub(nr, &vmap_lazy_nr);
575 
576         if (nr || force_flush)
577                 flush_tlb_kernel_range(*start, *end);
578 
579         if (nr) {
580                 spin_lock(&vmap_area_lock);
581                 list_for_each_entry_safe(va, n_va, &valist, purge_list)
582                         __free_vmap_area(va);
583                 spin_unlock(&vmap_area_lock);
584         }
585         spin_unlock(&purge_lock);
586 }
587 
588 /*
589  * Kick off a purge of the outstanding lazy areas. Don't bother if somebody
590  * is already purging.
591  */
592 static void try_purge_vmap_area_lazy(void)
593 {
594         unsigned long start = ULONG_MAX, end = 0;
595 
596         __purge_vmap_area_lazy(&start, &end, 0, 0);
597 }
598 
599 /*
600  * Kick off a purge of the outstanding lazy areas.
601  */
602 static void purge_vmap_area_lazy(void)
603 {
604         unsigned long start = ULONG_MAX, end = 0;
605 
606         __purge_vmap_area_lazy(&start, &end, 1, 0);
607 }
608 
609 /*
610  * Free and unmap a vmap area, caller ensuring flush_cache_vunmap had been
611  * called for the correct range previously.
612  */
613 static void free_unmap_vmap_area_noflush(struct vmap_area *va)
614 {
615         va->flags |= VM_LAZY_FREE;
616         atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr);
617         if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages()))
618                 try_purge_vmap_area_lazy();
619 }
620 
621 /*
622  * Free and unmap a vmap area
623  */
624 static void free_unmap_vmap_area(struct vmap_area *va)
625 {
626         flush_cache_vunmap(va->va_start, va->va_end);
627         free_unmap_vmap_area_noflush(va);
628 }
629 
630 static struct vmap_area *find_vmap_area(unsigned long addr)
631 {
632         struct vmap_area *va;
633 
634         spin_lock(&vmap_area_lock);
635         va = __find_vmap_area(addr);
636         spin_unlock(&vmap_area_lock);
637 
638         return va;
639 }
640 
641 static void free_unmap_vmap_area_addr(unsigned long addr)
642 {
643         struct vmap_area *va;
644 
645         va = find_vmap_area(addr);
646         BUG_ON(!va);
647         free_unmap_vmap_area(va);
648 }
649 
650 
651 /*** Per cpu kva allocator ***/
652 
653 /*
654  * vmap space is limited especially on 32 bit architectures. Ensure there is
655  * room for at least 16 percpu vmap blocks per CPU.
656  */
657 /*
658  * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
659  * to #define VMALLOC_SPACE             (VMALLOC_END-VMALLOC_START). Guess
660  * instead (we just need a rough idea)
661  */
662 #if BITS_PER_LONG == 32
663 #define VMALLOC_SPACE           (128UL*1024*1024)
664 #else
665 #define VMALLOC_SPACE           (128UL*1024*1024*1024)
666 #endif
667 
668 #define VMALLOC_PAGES           (VMALLOC_SPACE / PAGE_SIZE)
669 #define VMAP_MAX_ALLOC          BITS_PER_LONG   /* 256K with 4K pages */
670 #define VMAP_BBMAP_BITS_MAX     1024    /* 4MB with 4K pages */
671 #define VMAP_BBMAP_BITS_MIN     (VMAP_MAX_ALLOC*2)
672 #define VMAP_MIN(x, y)          ((x) < (y) ? (x) : (y)) /* can't use min() */
673 #define VMAP_MAX(x, y)          ((x) > (y) ? (x) : (y)) /* can't use max() */
674 #define VMAP_BBMAP_BITS         \
675                 VMAP_MIN(VMAP_BBMAP_BITS_MAX,   \
676                 VMAP_MAX(VMAP_BBMAP_BITS_MIN,   \
677                         VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
678 
679 #define VMAP_BLOCK_SIZE         (VMAP_BBMAP_BITS * PAGE_SIZE)
680 
681 static bool vmap_initialized __read_mostly = false;
682 
683 struct vmap_block_queue {
684         spinlock_t lock;
685         struct list_head free;
686 };
687 
688 struct vmap_block {
689         spinlock_t lock;
690         struct vmap_area *va;
691         struct vmap_block_queue *vbq;
692         unsigned long free, dirty;
693         DECLARE_BITMAP(alloc_map, VMAP_BBMAP_BITS);
694         DECLARE_BITMAP(dirty_map, VMAP_BBMAP_BITS);
695         struct list_head free_list;
696         struct rcu_head rcu_head;
697         struct list_head purge;
698 };
699 
700 /* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
701 static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
702 
703 /*
704  * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block
705  * in the free path. Could get rid of this if we change the API to return a
706  * "cookie" from alloc, to be passed to free. But no big deal yet.
707  */
708 static DEFINE_SPINLOCK(vmap_block_tree_lock);
709 static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
710 
711 /*
712  * We should probably have a fallback mechanism to allocate virtual memory
713  * out of partially filled vmap blocks. However vmap block sizing should be
714  * fairly reasonable according to the vmalloc size, so it shouldn't be a
715  * big problem.
716  */
717 
718 static unsigned long addr_to_vb_idx(unsigned long addr)
719 {
720         addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
721         addr /= VMAP_BLOCK_SIZE;
722         return addr;
723 }
724 
725 static struct vmap_block *new_vmap_block(gfp_t gfp_mask)
726 {
727         struct vmap_block_queue *vbq;
728         struct vmap_block *vb;
729         struct vmap_area *va;
730         unsigned long vb_idx;
731         int node, err;
732 
733         node = numa_node_id();
734 
735         vb = kmalloc_node(sizeof(struct vmap_block),
736                         gfp_mask & GFP_RECLAIM_MASK, node);
737         if (unlikely(!vb))
738                 return ERR_PTR(-ENOMEM);
739 
740         va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
741                                         VMALLOC_START, VMALLOC_END,
742                                         node, gfp_mask);
743         if (unlikely(IS_ERR(va))) {
744                 kfree(vb);
745                 return ERR_PTR(PTR_ERR(va));
746         }
747 
748         err = radix_tree_preload(gfp_mask);
749         if (unlikely(err)) {
750                 kfree(vb);
751                 free_vmap_area(va);
752                 return ERR_PTR(err);
753         }
754 
755         spin_lock_init(&vb->lock);
756         vb->va = va;
757         vb->free = VMAP_BBMAP_BITS;
758         vb->dirty = 0;
759         bitmap_zero(vb->alloc_map, VMAP_BBMAP_BITS);
760         bitmap_zero(vb->dirty_map, VMAP_BBMAP_BITS);
761         INIT_LIST_HEAD(&vb->free_list);
762 
763         vb_idx = addr_to_vb_idx(va->va_start);
764         spin_lock(&vmap_block_tree_lock);
765         err = radix_tree_insert(&vmap_block_tree, vb_idx, vb);
766         spin_unlock(&vmap_block_tree_lock);
767         BUG_ON(err);
768         radix_tree_preload_end();
769 
770         vbq = &get_cpu_var(vmap_block_queue);
771         vb->vbq = vbq;
772         spin_lock(&vbq->lock);
773         list_add_rcu(&vb->free_list, &vbq->free);
774         spin_unlock(&vbq->lock);
775         put_cpu_var(vmap_cpu_blocks);
776 
777         return vb;
778 }
779 
780 static void rcu_free_vb(struct rcu_head *head)
781 {
782         struct vmap_block *vb = container_of(head, struct vmap_block, rcu_head);
783 
784         kfree(vb);
785 }
786 
787 static void free_vmap_block(struct vmap_block *vb)
788 {
789         struct vmap_block *tmp;
790         unsigned long vb_idx;
791 
792         vb_idx = addr_to_vb_idx(vb->va->va_start);
793         spin_lock(&vmap_block_tree_lock);
794         tmp = radix_tree_delete(&vmap_block_tree, vb_idx);
795         spin_unlock(&vmap_block_tree_lock);
796         BUG_ON(tmp != vb);
797 
798         free_unmap_vmap_area_noflush(vb->va);
799         call_rcu(&vb->rcu_head, rcu_free_vb);
800 }
801 
802 static void purge_fragmented_blocks(int cpu)
803 {
804         LIST_HEAD(purge);
805         struct vmap_block *vb;
806         struct vmap_block *n_vb;
807         struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
808 
809         rcu_read_lock();
810         list_for_each_entry_rcu(vb, &vbq->free, free_list) {
811 
812                 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
813                         continue;
814 
815                 spin_lock(&vb->lock);
816                 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
817                         vb->free = 0; /* prevent further allocs after releasing lock */
818                         vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
819                         bitmap_fill(vb->alloc_map, VMAP_BBMAP_BITS);
820                         bitmap_fill(vb->dirty_map, VMAP_BBMAP_BITS);
821                         spin_lock(&vbq->lock);
822                         list_del_rcu(&vb->free_list);
823                         spin_unlock(&vbq->lock);
824                         spin_unlock(&vb->lock);
825                         list_add_tail(&vb->purge, &purge);
826                 } else
827                         spin_unlock(&vb->lock);
828         }
829         rcu_read_unlock();
830 
831         list_for_each_entry_safe(vb, n_vb, &purge, purge) {
832                 list_del(&vb->purge);
833                 free_vmap_block(vb);
834         }
835 }
836 
837 static void purge_fragmented_blocks_thiscpu(void)
838 {
839         purge_fragmented_blocks(smp_processor_id());
840 }
841 
842 static void purge_fragmented_blocks_allcpus(void)
843 {
844         int cpu;
845 
846         for_each_possible_cpu(cpu)
847                 purge_fragmented_blocks(cpu);
848 }
849 
850 static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
851 {
852         struct vmap_block_queue *vbq;
853         struct vmap_block *vb;
854         unsigned long addr = 0;
855         unsigned int order;
856         int purge = 0;
857 
858         BUG_ON(size & ~PAGE_MASK);
859         BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
860         order = get_order(size);
861 
862 again:
863         rcu_read_lock();
864         vbq = &get_cpu_var(vmap_block_queue);
865         list_for_each_entry_rcu(vb, &vbq->free, free_list) {
866                 int i;
867 
868                 spin_lock(&vb->lock);
869                 if (vb->free < 1UL << order)
870                         goto next;
871                 i = bitmap_find_free_region(vb->alloc_map,
872                                                 VMAP_BBMAP_BITS, order);
873 
874                 if (i < 0) {
875                         if (vb->free + vb->dirty == VMAP_BBMAP_BITS) {
876                                 /* fragmented and no outstanding allocations */
877                                 BUG_ON(vb->dirty != VMAP_BBMAP_BITS);
878                                 purge = 1;
879                         }
880                         goto next;
881                 }
882                 addr = vb->va->va_start + (i << PAGE_SHIFT);
883                 BUG_ON(addr_to_vb_idx(addr) !=
884                                 addr_to_vb_idx(vb->va->va_start));
885                 vb->free -= 1UL << order;
886                 if (vb->free == 0) {
887                         spin_lock(&vbq->lock);
888                         list_del_rcu(&vb->free_list);
889                         spin_unlock(&vbq->lock);
890                 }
891                 spin_unlock(&vb->lock);
892                 break;
893 next:
894                 spin_unlock(&vb->lock);
895         }
896 
897         if (purge)
898                 purge_fragmented_blocks_thiscpu();
899 
900         put_cpu_var(vmap_cpu_blocks);
901         rcu_read_unlock();
902 
903         if (!addr) {
904                 vb = new_vmap_block(gfp_mask);
905                 if (IS_ERR(vb))
906                         return vb;
907                 goto again;
908         }
909 
910         return (void *)addr;
911 }
912 
913 static void vb_free(const void *addr, unsigned long size)
914 {
915         unsigned long offset;
916         unsigned long vb_idx;
917         unsigned int order;
918         struct vmap_block *vb;
919 
920         BUG_ON(size & ~PAGE_MASK);
921         BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
922 
923         flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
924 
925         order = get_order(size);
926 
927         offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
928 
929         vb_idx = addr_to_vb_idx((unsigned long)addr);
930         rcu_read_lock();
931         vb = radix_tree_lookup(&vmap_block_tree, vb_idx);
932         rcu_read_unlock();
933         BUG_ON(!vb);
934 
935         spin_lock(&vb->lock);
936         BUG_ON(bitmap_allocate_region(vb->dirty_map, offset >> PAGE_SHIFT, order));
937 
938         vb->dirty += 1UL << order;
939         if (vb->dirty == VMAP_BBMAP_BITS) {
940                 BUG_ON(vb->free);
941                 spin_unlock(&vb->lock);
942                 free_vmap_block(vb);
943         } else
944                 spin_unlock(&vb->lock);
945 }
946 
947 /**
948  * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
949  *
950  * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
951  * to amortize TLB flushing overheads. What this means is that any page you
952  * have now, may, in a former life, have been mapped into kernel virtual
953  * address by the vmap layer and so there might be some CPUs with TLB entries
954  * still referencing that page (additional to the regular 1:1 kernel mapping).
955  *
956  * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
957  * be sure that none of the pages we have control over will have any aliases
958  * from the vmap layer.
959  */
960 void vm_unmap_aliases(void)
961 {
962         unsigned long start = ULONG_MAX, end = 0;
963         int cpu;
964         int flush = 0;
965 
966         if (unlikely(!vmap_initialized))
967                 return;
968 
969         for_each_possible_cpu(cpu) {
970                 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
971                 struct vmap_block *vb;
972 
973                 rcu_read_lock();
974                 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
975                         int i;
976 
977                         spin_lock(&vb->lock);
978                         i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS);
979                         while (i < VMAP_BBMAP_BITS) {
980                                 unsigned long s, e;
981                                 int j;
982                                 j = find_next_zero_bit(vb->dirty_map,
983                                         VMAP_BBMAP_BITS, i);
984 
985                                 s = vb->va->va_start + (i << PAGE_SHIFT);
986                                 e = vb->va->va_start + (j << PAGE_SHIFT);
987                                 vunmap_page_range(s, e);
988                                 flush = 1;
989 
990                                 if (s < start)
991                                         start = s;
992                                 if (e > end)
993                                         end = e;
994 
995                                 i = j;
996                                 i = find_next_bit(vb->dirty_map,
997                                                         VMAP_BBMAP_BITS, i);
998                         }
999                         spin_unlock(&vb->lock);
1000                 }
1001                 rcu_read_unlock();
1002         }
1003 
1004         __purge_vmap_area_lazy(&start, &end, 1, flush);
1005 }
1006 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
1007 
1008 /**
1009  * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
1010  * @mem: the pointer returned by vm_map_ram
1011  * @count: the count passed to that vm_map_ram call (cannot unmap partial)
1012  */
1013 void vm_unmap_ram(const void *mem, unsigned int count)
1014 {
1015         unsigned long size = count << PAGE_SHIFT;
1016         unsigned long addr = (unsigned long)mem;
1017 
1018         BUG_ON(!addr);
1019         BUG_ON(addr < VMALLOC_START);
1020         BUG_ON(addr > VMALLOC_END);
1021         BUG_ON(addr & (PAGE_SIZE-1));
1022 
1023         debug_check_no_locks_freed(mem, size);
1024         vmap_debug_free_range(addr, addr+size);
1025 
1026         if (likely(count <= VMAP_MAX_ALLOC))
1027                 vb_free(mem, size);
1028         else
1029                 free_unmap_vmap_area_addr(addr);
1030 }
1031 EXPORT_SYMBOL(vm_unmap_ram);
1032 
1033 /**
1034  * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
1035  * @pages: an array of pointers to the pages to be mapped
1036  * @count: number of pages
1037  * @node: prefer to allocate data structures on this node
1038  * @prot: memory protection to use. PAGE_KERNEL for regular RAM
1039  *
1040  * Returns: a pointer to the address that has been mapped, or %NULL on failure
1041  */
1042 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
1043 {
1044         unsigned long size = count << PAGE_SHIFT;
1045         unsigned long addr;
1046         void *mem;
1047 
1048         if (likely(count <= VMAP_MAX_ALLOC)) {
1049                 mem = vb_alloc(size, GFP_KERNEL);
1050                 if (IS_ERR(mem))
1051                         return NULL;
1052                 addr = (unsigned long)mem;
1053         } else {
1054                 struct vmap_area *va;
1055                 va = alloc_vmap_area(size, PAGE_SIZE,
1056                                 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
1057                 if (IS_ERR(va))
1058                         return NULL;
1059 
1060                 addr = va->va_start;
1061                 mem = (void *)addr;
1062         }
1063         if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
1064                 vm_unmap_ram(mem, count);
1065                 return NULL;
1066         }
1067         return mem;
1068 }
1069 EXPORT_SYMBOL(vm_map_ram);
1070 
1071 /**
1072  * vm_area_register_early - register vmap area early during boot
1073  * @vm: vm_struct to register
1074  * @align: requested alignment
1075  *
1076  * This function is used to register kernel vm area before
1077  * vmalloc_init() is called.  @vm->size and @vm->flags should contain
1078  * proper values on entry and other fields should be zero.  On return,
1079  * vm->addr contains the allocated address.
1080  *
1081  * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1082  */
1083 void __init vm_area_register_early(struct vm_struct *vm, size_t align)
1084 {
1085         static size_t vm_init_off __initdata;
1086         unsigned long addr;
1087 
1088         addr = ALIGN(VMALLOC_START + vm_init_off, align);
1089         vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
1090 
1091         vm->addr = (void *)addr;
1092 
1093         vm->next = vmlist;
1094         vmlist = vm;
1095 }
1096 
1097 void __init vmalloc_init(void)
1098 {
1099         struct vmap_area *va;
1100         struct vm_struct *tmp;
1101         int i;
1102 
1103         for_each_possible_cpu(i) {
1104                 struct vmap_block_queue *vbq;
1105 
1106                 vbq = &per_cpu(vmap_block_queue, i);
1107                 spin_lock_init(&vbq->lock);
1108                 INIT_LIST_HEAD(&vbq->free);
1109         }
1110 
1111         /* Import existing vmlist entries. */
1112         for (tmp = vmlist; tmp; tmp = tmp->next) {
1113                 va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT);
1114                 va->flags = tmp->flags | VM_VM_AREA;
1115                 va->va_start = (unsigned long)tmp->addr;
1116                 va->va_end = va->va_start + tmp->size;
1117                 __insert_vmap_area(va);
1118         }
1119 
1120         vmap_area_pcpu_hole = VMALLOC_END;
1121 
1122         vmap_initialized = true;
1123 }
1124 
1125 /**
1126  * map_kernel_range_noflush - map kernel VM area with the specified pages
1127  * @addr: start of the VM area to map
1128  * @size: size of the VM area to map
1129  * @prot: page protection flags to use
1130  * @pages: pages to map
1131  *
1132  * Map PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1133  * specify should have been allocated using get_vm_area() and its
1134  * friends.
1135  *
1136  * NOTE:
1137  * This function does NOT do any cache flushing.  The caller is
1138  * responsible for calling flush_cache_vmap() on to-be-mapped areas
1139  * before calling this function.
1140  *
1141  * RETURNS:
1142  * The number of pages mapped on success, -errno on failure.
1143  */
1144 int map_kernel_range_noflush(unsigned long addr, unsigned long size,
1145                              pgprot_t prot, struct page **pages)
1146 {
1147         return vmap_page_range_noflush(addr, addr + size, prot, pages);
1148 }
1149 
1150 /**
1151  * unmap_kernel_range_noflush - unmap kernel VM area
1152  * @addr: start of the VM area to unmap
1153  * @size: size of the VM area to unmap
1154  *
1155  * Unmap PFN_UP(@size) pages at @addr.  The VM area @addr and @size
1156  * specify should have been allocated using get_vm_area() and its
1157  * friends.
1158  *
1159  * NOTE:
1160  * This function does NOT do any cache flushing.  The caller is
1161  * responsible for calling flush_cache_vunmap() on to-be-mapped areas
1162  * before calling this function and flush_tlb_kernel_range() after.
1163  */
1164 void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
1165 {
1166         vunmap_page_range(addr, addr + size);
1167 }
1168 
1169 /**
1170  * unmap_kernel_range - unmap kernel VM area and flush cache and TLB
1171  * @addr: start of the VM area to unmap
1172  * @size: size of the VM area to unmap
1173  *
1174  * Similar to unmap_kernel_range_noflush() but flushes vcache before
1175  * the unmapping and tlb after.
1176  */
1177 void unmap_kernel_range(unsigned long addr, unsigned long size)
1178 {
1179         unsigned long end = addr + size;
1180 
1181         flush_cache_vunmap(addr, end);
1182         vunmap_page_range(addr, end);
1183         flush_tlb_kernel_range(addr, end);
1184 }
1185 
1186 int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
1187 {
1188         unsigned long addr = (unsigned long)area->addr;
1189         unsigned long end = addr + area->size - PAGE_SIZE;
1190         int err;
1191 
1192         err = vmap_page_range(addr, end, prot, *pages);
1193         if (err > 0) {
1194                 *pages += err;
1195                 err = 0;
1196         }
1197 
1198         return err;
1199 }
1200 EXPORT_SYMBOL_GPL(map_vm_area);
1201 
1202 /*** Old vmalloc interfaces ***/
1203 DEFINE_RWLOCK(vmlist_lock);
1204 struct vm_struct *vmlist;
1205 
1206 static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1207                               unsigned long flags, void *caller)
1208 {
1209         vm->flags = flags;
1210         vm->addr = (void *)va->va_start;
1211         vm->size = va->va_end - va->va_start;
1212         vm->caller = caller;
1213         va->private = vm;
1214         va->flags |= VM_VM_AREA;
1215 }
1216 
1217 static void insert_vmalloc_vmlist(struct vm_struct *vm)
1218 {
1219         struct vm_struct *tmp, **p;
1220 
1221         vm->flags &= ~VM_UNLIST;
1222 
1223         write_lock(&vmlist_lock);
1224         for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1225                 if (tmp->addr >= vm->addr)
1226                         break;
1227         }
1228         vm->next = *p;
1229         *p = vm;
1230         write_unlock(&vmlist_lock);
1231 }
1232 
1233 static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1234                               unsigned long flags, void *caller)
1235 {
1236         setup_vmalloc_vm(vm, va, flags, caller);
1237         insert_vmalloc_vmlist(vm);
1238 }
1239 
1240 static struct vm_struct *__get_vm_area_node(unsigned long size,
1241                 unsigned long align, unsigned long flags, unsigned long start,
1242                 unsigned long end, int node, gfp_t gfp_mask, void *caller)
1243 {
1244         static struct vmap_area *va;
1245         struct vm_struct *area;
1246 
1247         BUG_ON(in_interrupt());
1248         if (flags & VM_IOREMAP) {
1249                 int bit = fls(size);
1250 
1251                 if (bit > IOREMAP_MAX_ORDER)
1252                         bit = IOREMAP_MAX_ORDER;
1253                 else if (bit < PAGE_SHIFT)
1254                         bit = PAGE_SHIFT;
1255 
1256                 align = 1ul << bit;
1257         }
1258 
1259         size = PAGE_ALIGN(size);
1260         if (unlikely(!size))
1261                 return NULL;
1262 
1263         area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
1264         if (unlikely(!area))
1265                 return NULL;
1266 
1267         /*
1268          * We always allocate a guard page.
1269          */
1270         size += PAGE_SIZE;
1271 
1272         va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
1273         if (IS_ERR(va)) {
1274                 kfree(area);
1275                 return NULL;
1276         }
1277 
1278         /*
1279          * When this function is called from __vmalloc_node,
1280          * we do not add vm_struct to vmlist here to avoid
1281          * accessing uninitialized members of vm_struct such as
1282          * pages and nr_pages fields. They will be set later.
1283          * To distinguish it from others, we use a VM_UNLIST flag.
1284          */
1285         if (flags & VM_UNLIST)
1286                 setup_vmalloc_vm(area, va, flags, caller);
1287         else
1288                 insert_vmalloc_vm(area, va, flags, caller);
1289 
1290         return area;
1291 }
1292 
1293 struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
1294                                 unsigned long start, unsigned long end)
1295 {
1296         return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
1297                                                 __builtin_return_address(0));
1298 }
1299 EXPORT_SYMBOL_GPL(__get_vm_area);
1300 
1301 struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
1302                                        unsigned long start, unsigned long end,
1303                                        void *caller)
1304 {
1305         return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
1306                                   caller);
1307 }
1308 
1309 /**
1310  *      get_vm_area  -  reserve a contiguous kernel virtual area
1311  *      @size:          size of the area
1312  *      @flags:         %VM_IOREMAP for I/O mappings or VM_ALLOC
1313  *
1314  *      Search an area of @size in the kernel virtual mapping area,
1315  *      and reserved it for out purposes.  Returns the area descriptor
1316  *      on success or %NULL on failure.
1317  */
1318 struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
1319 {
1320         return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1321                                 -1, GFP_KERNEL, __builtin_return_address(0));
1322 }
1323 
1324 struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
1325                                 void *caller)
1326 {
1327         return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1328                                                 -1, GFP_KERNEL, caller);
1329 }
1330 
1331 struct vm_struct *get_vm_area_node(unsigned long size, unsigned long flags,
1332                                    int node, gfp_t gfp_mask)
1333 {
1334         return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1335                                   node, gfp_mask, __builtin_return_address(0));
1336 }
1337 
1338 static struct vm_struct *find_vm_area(const void *addr)
1339 {
1340         struct vmap_area *va;
1341 
1342         va = find_vmap_area((unsigned long)addr);
1343         if (va && va->flags & VM_VM_AREA)
1344                 return va->private;
1345 
1346         return NULL;
1347 }
1348 
1349 /**
1350  *      remove_vm_area  -  find and remove a continuous kernel virtual area
1351  *      @addr:          base address
1352  *
1353  *      Search for the kernel VM area starting at @addr, and remove it.
1354  *      This function returns the found VM area, but using it is NOT safe
1355  *      on SMP machines, except for its size or flags.
1356  */
1357 struct vm_struct *remove_vm_area(const void *addr)
1358 {
1359         struct vmap_area *va;
1360 
1361         va = find_vmap_area((unsigned long)addr);
1362         if (va && va->flags & VM_VM_AREA) {
1363                 struct vm_struct *vm = va->private;
1364 
1365                 if (!(vm->flags & VM_UNLIST)) {
1366                         struct vm_struct *tmp, **p;
1367                         /*
1368                          * remove from list and disallow access to
1369                          * this vm_struct before unmap. (address range
1370                          * confliction is maintained by vmap.)
1371                          */
1372                         write_lock(&vmlist_lock);
1373                         for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next)
1374                                 ;
1375                         *p = tmp->next;
1376                         write_unlock(&vmlist_lock);
1377                 }
1378 
1379                 vmap_debug_free_range(va->va_start, va->va_end);
1380                 free_unmap_vmap_area(va);
1381                 vm->size -= PAGE_SIZE;
1382 
1383                 return vm;
1384         }
1385         return NULL;
1386 }
1387 
1388 static void __vunmap(const void *addr, int deallocate_pages)
1389 {
1390         struct vm_struct *area;
1391 
1392         if (!addr)
1393                 return;
1394 
1395         if ((PAGE_SIZE-1) & (unsigned long)addr) {
1396                 WARN(1, KERN_ERR "Trying to vfree() bad address (%p)\n", addr);
1397                 return;
1398         }
1399 
1400         area = remove_vm_area(addr);
1401         if (unlikely(!area)) {
1402                 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
1403                                 addr);
1404                 return;
1405         }
1406 
1407         debug_check_no_locks_freed(addr, area->size);
1408         debug_check_no_obj_freed(addr, area->size);
1409 
1410         if (deallocate_pages) {
1411                 int i;
1412 
1413                 for (i = 0; i < area->nr_pages; i++) {
1414                         struct page *page = area->pages[i];
1415 
1416                         BUG_ON(!page);
1417                         __free_page(page);
1418                 }
1419 
1420                 if (area->flags & VM_VPAGES)
1421                         vfree(area->pages);
1422                 else
1423                         kfree(area->pages);
1424         }
1425 
1426         kfree(area);
1427         return;
1428 }
1429 
1430 /**
1431  *      vfree  -  release memory allocated by vmalloc()
1432  *      @addr:          memory base address
1433  *
1434  *      Free the virtually continuous memory area starting at @addr, as
1435  *      obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
1436  *      NULL, no operation is performed.
1437  *
1438  *      Must not be called in interrupt context.
1439  */
1440 void vfree(const void *addr)
1441 {
1442         BUG_ON(in_interrupt());
1443 
1444         kmemleak_free(addr);
1445 
1446         __vunmap(addr, 1);
1447 }
1448 EXPORT_SYMBOL(vfree);
1449 
1450 /**
1451  *      vunmap  -  release virtual mapping obtained by vmap()
1452  *      @addr:          memory base address
1453  *
1454  *      Free the virtually contiguous memory area starting at @addr,
1455  *      which was created from the page array passed to vmap().
1456  *
1457  *      Must not be called in interrupt context.
1458  */
1459 void vunmap(const void *addr)
1460 {
1461         BUG_ON(in_interrupt());
1462         might_sleep();
1463         __vunmap(addr, 0);
1464 }
1465 EXPORT_SYMBOL(vunmap);
1466 
1467 /**
1468  *      vmap  -  map an array of pages into virtually contiguous space
1469  *      @pages:         array of page pointers
1470  *      @count:         number of pages to map
1471  *      @flags:         vm_area->flags
1472  *      @prot:          page protection for the mapping
1473  *
1474  *      Maps @count pages from @pages into contiguous kernel virtual
1475  *      space.
1476  */
1477 void *vmap(struct page **pages, unsigned int count,
1478                 unsigned long flags, pgprot_t prot)
1479 {
1480         struct vm_struct *area;
1481 
1482         might_sleep();
1483 
1484         if (count > totalram_pages)
1485                 return NULL;
1486 
1487         area = get_vm_area_caller((count << PAGE_SHIFT), flags,
1488                                         __builtin_return_address(0));
1489         if (!area)
1490                 return NULL;
1491 
1492         if (map_vm_area(area, prot, &pages)) {
1493                 vunmap(area->addr);
1494                 return NULL;
1495         }
1496 
1497         return area->addr;
1498 }
1499 EXPORT_SYMBOL(vmap);
1500 
1501 static void *__vmalloc_node(unsigned long size, unsigned long align,
1502                             gfp_t gfp_mask, pgprot_t prot,
1503                             int node, void *caller);
1504 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
1505                                  pgprot_t prot, int node, void *caller)
1506 {
1507         struct page **pages;
1508         unsigned int nr_pages, array_size, i;
1509 
1510         nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
1511         array_size = (nr_pages * sizeof(struct page *));
1512 
1513         area->nr_pages = nr_pages;
1514         /* Please note that the recursion is strictly bounded. */
1515         if (array_size > PAGE_SIZE) {
1516                 pages = __vmalloc_node(array_size, 1, gfp_mask | __GFP_ZERO,
1517                                 PAGE_KERNEL, node, caller);
1518                 area->flags |= VM_VPAGES;
1519         } else {
1520                 pages = kmalloc_node(array_size,
1521                                 (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO,
1522                                 node);
1523         }
1524         area->pages = pages;
1525         area->caller = caller;
1526         if (!area->pages) {
1527                 remove_vm_area(area->addr);
1528                 kfree(area);
1529                 return NULL;
1530         }
1531 
1532         for (i = 0; i < area->nr_pages; i++) {
1533                 struct page *page;
1534 
1535                 if (node < 0)
1536                         page = alloc_page(gfp_mask);
1537                 else
1538                         page = alloc_pages_node(node, gfp_mask, 0);
1539 
1540                 if (unlikely(!page)) {
1541                         /* Successfully allocated i pages, free them in __vunmap() */
1542                         area->nr_pages = i;
1543                         goto fail;
1544                 }
1545                 area->pages[i] = page;
1546         }
1547 
1548         if (map_vm_area(area, prot, &pages))
1549                 goto fail;
1550         return area->addr;
1551 
1552 fail:
1553         vfree(area->addr);
1554         return NULL;
1555 }
1556 
1557 void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
1558 {
1559         void *addr = __vmalloc_area_node(area, gfp_mask, prot, -1,
1560                                          __builtin_return_address(0));
1561 
1562         /*
1563          * A ref_count = 3 is needed because the vm_struct and vmap_area
1564          * structures allocated in the __get_vm_area_node() function contain
1565          * references to the virtual address of the vmalloc'ed block.
1566          */
1567         kmemleak_alloc(addr, area->size - PAGE_SIZE, 3, gfp_mask);
1568 
1569         return addr;
1570 }
1571 
1572 /**
1573  *      __vmalloc_node  -  allocate virtually contiguous memory
1574  *      @size:          allocation size
1575  *      @align:         desired alignment
1576  *      @gfp_mask:      flags for the page level allocator
1577  *      @prot:          protection mask for the allocated pages
1578  *      @node:          node to use for allocation or -1
1579  *      @caller:        caller's return address
1580  *
1581  *      Allocate enough pages to cover @size from the page level
1582  *      allocator with @gfp_mask flags.  Map them into contiguous
1583  *      kernel virtual space, using a pagetable protection of @prot.
1584  */
1585 static void *__vmalloc_node(unsigned long size, unsigned long align,
1586                             gfp_t gfp_mask, pgprot_t prot,
1587                             int node, void *caller)
1588 {
1589         struct vm_struct *area;
1590         void *addr;
1591         unsigned long real_size = size;
1592 
1593         size = PAGE_ALIGN(size);
1594         if (!size || (size >> PAGE_SHIFT) > totalram_pages)
1595                 return NULL;
1596 
1597         area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST,
1598                                   VMALLOC_START, VMALLOC_END, node,
1599                                   gfp_mask, caller);
1600 
1601         if (!area)
1602                 return NULL;
1603 
1604         addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
1605 
1606         /*
1607          * In this function, newly allocated vm_struct is not added
1608          * to vmlist at __get_vm_area_node(). so, it is added here.
1609          */
1610         insert_vmalloc_vmlist(area);
1611 
1612         /*
1613          * A ref_count = 3 is needed because the vm_struct and vmap_area
1614          * structures allocated in the __get_vm_area_node() function contain
1615          * references to the virtual address of the vmalloc'ed block.
1616          */
1617         kmemleak_alloc(addr, real_size, 3, gfp_mask);
1618 
1619         return addr;
1620 }
1621 
1622 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
1623 {
1624         return __vmalloc_node(size, 1, gfp_mask, prot, -1,
1625                                 __builtin_return_address(0));
1626 }
1627 EXPORT_SYMBOL(__vmalloc);
1628 
1629 /**
1630  *      vmalloc  -  allocate virtually contiguous memory
1631  *      @size:          allocation size
1632  *      Allocate enough pages to cover @size from the page level
1633  *      allocator and map them into contiguous kernel virtual space.
1634  *
1635  *      For tight control over page level allocator and protection flags
1636  *      use __vmalloc() instead.
1637  */
1638 void *vmalloc(unsigned long size)
1639 {
1640         return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
1641                                         -1, __builtin_return_address(0));
1642 }
1643 EXPORT_SYMBOL(vmalloc);
1644 
1645 /**
1646  * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
1647  * @size: allocation size
1648  *
1649  * The resulting memory area is zeroed so it can be mapped to userspace
1650  * without leaking data.
1651  */
1652 void *vmalloc_user(unsigned long size)
1653 {
1654         struct vm_struct *area;
1655         void *ret;
1656 
1657         ret = __vmalloc_node(size, SHMLBA,
1658                              GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
1659                              PAGE_KERNEL, -1, __builtin_return_address(0));
1660         if (ret) {
1661                 area = find_vm_area(ret);
1662                 area->flags |= VM_USERMAP;
1663         }
1664         return ret;
1665 }
1666 EXPORT_SYMBOL(vmalloc_user);
1667 
1668 /**
1669  *      vmalloc_node  -  allocate memory on a specific node
1670  *      @size:          allocation size
1671  *      @node:          numa node
1672  *
1673  *      Allocate enough pages to cover @size from the page level
1674  *      allocator and map them into contiguous kernel virtual space.
1675  *
1676  *      For tight control over page level allocator and protection flags
1677  *      use __vmalloc() instead.
1678  */
1679 void *vmalloc_node(unsigned long size, int node)
1680 {
1681         return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
1682                                         node, __builtin_return_address(0));
1683 }
1684 EXPORT_SYMBOL(vmalloc_node);
1685 
1686 #ifndef PAGE_KERNEL_EXEC
1687 # define PAGE_KERNEL_EXEC PAGE_KERNEL
1688 #endif
1689 
1690 /**
1691  *      vmalloc_exec  -  allocate virtually contiguous, executable memory
1692  *      @size:          allocation size
1693  *
1694  *      Kernel-internal function to allocate enough pages to cover @size
1695  *      the page level allocator and map them into contiguous and
1696  *      executable kernel virtual space.
1697  *
1698  *      For tight control over page level allocator and protection flags
1699  *      use __vmalloc() instead.
1700  */
1701 
1702 void *vmalloc_exec(unsigned long size)
1703 {
1704         return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
1705                               -1, __builtin_return_address(0));
1706 }
1707 
1708 #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
1709 #define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
1710 #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
1711 #define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
1712 #else
1713 #define GFP_VMALLOC32 GFP_KERNEL
1714 #endif
1715 
1716 /**
1717  *      vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
1718  *      @size:          allocation size
1719  *
1720  *      Allocate enough 32bit PA addressable pages to cover @size from the
1721  *      page level allocator and map them into contiguous kernel virtual space.
1722  */
1723 void *vmalloc_32(unsigned long size)
1724 {
1725         return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
1726                               -1, __builtin_return_address(0));
1727 }
1728 EXPORT_SYMBOL(vmalloc_32);
1729 
1730 /**
1731  * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
1732  *      @size:          allocation size
1733  *
1734  * The resulting memory area is 32bit addressable and zeroed so it can be
1735  * mapped to userspace without leaking data.
1736  */
1737 void *vmalloc_32_user(unsigned long size)
1738 {
1739         struct vm_struct *area;
1740         void *ret;
1741 
1742         ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
1743                              -1, __builtin_return_address(0));
1744         if (ret) {
1745                 area = find_vm_area(ret);
1746                 area->flags |= VM_USERMAP;
1747         }
1748         return ret;
1749 }
1750 EXPORT_SYMBOL(vmalloc_32_user);
1751 
1752 /*
1753  * small helper routine , copy contents to buf from addr.
1754  * If the page is not present, fill zero.
1755  */
1756 
1757 static int aligned_vread(char *buf, char *addr, unsigned long count)
1758 {
1759         struct page *p;
1760         int copied = 0;
1761 
1762         while (count) {
1763                 unsigned long offset, length;
1764 
1765                 offset = (unsigned long)addr & ~PAGE_MASK;
1766                 length = PAGE_SIZE - offset;
1767                 if (length > count)
1768                         length = count;
1769                 p = vmalloc_to_page(addr);
1770                 /*
1771                  * To do safe access to this _mapped_ area, we need
1772                  * lock. But adding lock here means that we need to add
1773                  * overhead of vmalloc()/vfree() calles for this _debug_
1774                  * interface, rarely used. Instead of that, we'll use
1775                  * kmap() and get small overhead in this access function.
1776                  */
1777                 if (p) {
1778                         /*
1779                          * we can expect USER0 is not used (see vread/vwrite's
1780                          * function description)
1781                          */
1782                         void *map = kmap_atomic(p, KM_USER0);
1783                         memcpy(buf, map + offset, length);
1784                         kunmap_atomic(map, KM_USER0);
1785                 } else
1786                         memset(buf, 0, length);
1787 
1788                 addr += length;
1789                 buf += length;
1790                 copied += length;
1791                 count -= length;
1792         }
1793         return copied;
1794 }
1795 
1796 static int aligned_vwrite(char *buf, char *addr, unsigned long count)
1797 {
1798         struct page *p;
1799         int copied = 0;
1800 
1801         while (count) {
1802                 unsigned long offset, length;
1803 
1804                 offset = (unsigned long)addr & ~PAGE_MASK;
1805                 length = PAGE_SIZE - offset;
1806                 if (length > count)
1807                         length = count;
1808                 p = vmalloc_to_page(addr);
1809                 /*
1810                  * To do safe access to this _mapped_ area, we need
1811                  * lock. But adding lock here means that we need to add
1812                  * overhead of vmalloc()/vfree() calles for this _debug_
1813                  * interface, rarely used. Instead of that, we'll use
1814                  * kmap() and get small overhead in this access function.
1815                  */
1816                 if (p) {
1817                         /*
1818                          * we can expect USER0 is not used (see vread/vwrite's
1819                          * function description)
1820                          */
1821                         void *map = kmap_atomic(p, KM_USER0);
1822                         memcpy(map + offset, buf, length);
1823                         kunmap_atomic(map, KM_USER0);
1824                 }
1825                 addr += length;
1826                 buf += length;
1827                 copied += length;
1828                 count -= length;
1829         }
1830         return copied;
1831 }
1832 
1833 /**
1834  *      vread() -  read vmalloc area in a safe way.
1835  *      @buf:           buffer for reading data
1836  *      @addr:          vm address.
1837  *      @count:         number of bytes to be read.
1838  *
1839  *      Returns # of bytes which addr and buf should be increased.
1840  *      (same number to @count). Returns 0 if [addr...addr+count) doesn't
1841  *      includes any intersect with alive vmalloc area.
1842  *
1843  *      This function checks that addr is a valid vmalloc'ed area, and
1844  *      copy data from that area to a given buffer. If the given memory range
1845  *      of [addr...addr+count) includes some valid address, data is copied to
1846  *      proper area of @buf. If there are memory holes, they'll be zero-filled.
1847  *      IOREMAP area is treated as memory hole and no copy is done.
1848  *
1849  *      If [addr...addr+count) doesn't includes any intersects with alive
1850  *      vm_struct area, returns 0.
1851  *      @buf should be kernel's buffer. Because this function uses KM_USER0,
1852  *      the caller should guarantee KM_USER0 is not used.
1853  *
1854  *      Note: In usual ops, vread() is never necessary because the caller
1855  *      should know vmalloc() area is valid and can use memcpy().
1856  *      This is for routines which have to access vmalloc area without
1857  *      any informaion, as /dev/kmem.
1858  *
1859  */
1860 
1861 long vread(char *buf, char *addr, unsigned long count)
1862 {
1863         struct vm_struct *tmp;
1864         char *vaddr, *buf_start = buf;
1865         unsigned long buflen = count;
1866         unsigned long n;
1867 
1868         /* Don't allow overflow */
1869         if ((unsigned long) addr + count < count)
1870                 count = -(unsigned long) addr;
1871 
1872         read_lock(&vmlist_lock);
1873         for (tmp = vmlist; count && tmp; tmp = tmp->next) {
1874                 vaddr = (char *) tmp->addr;
1875                 if (addr >= vaddr + tmp->size - PAGE_SIZE)
1876                         continue;
1877                 while (addr < vaddr) {
1878                         if (count == 0)
1879                                 goto finished;
1880                         *buf = '\0';
1881                         buf++;
1882                         addr++;
1883                         count--;
1884                 }
1885                 n = vaddr + tmp->size - PAGE_SIZE - addr;
1886                 if (n > count)
1887                         n = count;
1888                 if (!(tmp->flags & VM_IOREMAP))
1889                         aligned_vread(buf, addr, n);
1890                 else /* IOREMAP area is treated as memory hole */
1891                         memset(buf, 0, n);
1892                 buf += n;
1893                 addr += n;
1894                 count -= n;
1895         }
1896 finished:
1897         read_unlock(&vmlist_lock);
1898 
1899         if (buf == buf_start)
1900                 return 0;
1901         /* zero-fill memory holes */
1902         if (buf != buf_start + buflen)
1903                 memset(buf, 0, buflen - (buf - buf_start));
1904 
1905         return buflen;
1906 }
1907 
1908 /**
1909  *      vwrite() -  write vmalloc area in a safe way.
1910  *      @buf:           buffer for source data
1911  *      @addr:          vm address.
1912  *      @count:         number of bytes to be read.
1913  *
1914  *      Returns # of bytes which addr and buf should be incresed.
1915  *      (same number to @count).
1916  *      If [addr...addr+count) doesn't includes any intersect with valid
1917  *      vmalloc area, returns 0.
1918  *
1919  *      This function checks that addr is a valid vmalloc'ed area, and
1920  *      copy data from a buffer to the given addr. If specified range of
1921  *      [addr...addr+count) includes some valid address, data is copied from
1922  *      proper area of @buf. If there are memory holes, no copy to hole.
1923  *      IOREMAP area is treated as memory hole and no copy is done.
1924  *
1925  *      If [addr...addr+count) doesn't includes any intersects with alive
1926  *      vm_struct area, returns 0.
1927  *      @buf should be kernel's buffer. Because this function uses KM_USER0,
1928  *      the caller should guarantee KM_USER0 is not used.
1929  *
1930  *      Note: In usual ops, vwrite() is never necessary because the caller
1931  *      should know vmalloc() area is valid and can use memcpy().
1932  *      This is for routines which have to access vmalloc area without
1933  *      any informaion, as /dev/kmem.
1934  *
1935  *      The caller should guarantee KM_USER1 is not used.
1936  */
1937 
1938 long vwrite(char *buf, char *addr, unsigned long count)
1939 {
1940         struct vm_struct *tmp;
1941         char *vaddr;
1942         unsigned long n, buflen;
1943         int copied = 0;
1944 
1945         /* Don't allow overflow */
1946         if ((unsigned long) addr + count < count)
1947                 count = -(unsigned long) addr;
1948         buflen = count;
1949 
1950         read_lock(&vmlist_lock);
1951         for (tmp = vmlist; count && tmp; tmp = tmp->next) {
1952                 vaddr = (char *) tmp->addr;
1953                 if (addr >= vaddr + tmp->size - PAGE_SIZE)
1954                         continue;
1955                 while (addr < vaddr) {
1956                         if (count == 0)
1957                                 goto finished;
1958                         buf++;
1959                         addr++;
1960                         count--;
1961                 }
1962                 n = vaddr + tmp->size - PAGE_SIZE - addr;
1963                 if (n > count)
1964                         n = count;
1965                 if (!(tmp->flags & VM_IOREMAP)) {
1966                         aligned_vwrite(buf, addr, n);
1967                         copied++;
1968                 }
1969                 buf += n;
1970                 addr += n;
1971                 count -= n;
1972         }
1973 finished:
1974         read_unlock(&vmlist_lock);
1975         if (!copied)
1976                 return 0;
1977         return buflen;
1978 }
1979 
1980 /**
1981  *      remap_vmalloc_range  -  map vmalloc pages to userspace
1982  *      @vma:           vma to cover (map full range of vma)
1983  *      @addr:          vmalloc memory
1984  *      @pgoff:         number of pages into addr before first page to map
1985  *
1986  *      Returns:        0 for success, -Exxx on failure
1987  *
1988  *      This function checks that addr is a valid vmalloc'ed area, and
1989  *      that it is big enough to cover the vma. Will return failure if
1990  *      that criteria isn't met.
1991  *
1992  *      Similar to remap_pfn_range() (see mm/memory.c)
1993  */
1994 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1995                                                 unsigned long pgoff)
1996 {
1997         struct vm_struct *area;
1998         unsigned long uaddr = vma->vm_start;
1999         unsigned long usize = vma->vm_end - vma->vm_start;
2000 
2001         if ((PAGE_SIZE-1) & (unsigned long)addr)
2002                 return -EINVAL;
2003 
2004         area = find_vm_area(addr);
2005         if (!area)
2006                 return -EINVAL;
2007 
2008         if (!(area->flags & VM_USERMAP))
2009                 return -EINVAL;
2010 
2011         if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
2012                 return -EINVAL;
2013 
2014         addr += pgoff << PAGE_SHIFT;
2015         do {
2016                 struct page *page = vmalloc_to_page(addr);
2017                 int ret;
2018 
2019                 ret = vm_insert_page(vma, uaddr, page);
2020                 if (ret)
2021                         return ret;
2022 
2023                 uaddr += PAGE_SIZE;
2024                 addr += PAGE_SIZE;
2025                 usize -= PAGE_SIZE;
2026         } while (usize > 0);
2027 
2028         /* Prevent "things" like memory migration? VM_flags need a cleanup... */
2029         vma->vm_flags |= VM_RESERVED;
2030 
2031         return 0;
2032 }
2033 EXPORT_SYMBOL(remap_vmalloc_range);
2034 
2035 /*
2036  * Implement a stub for vmalloc_sync_all() if the architecture chose not to
2037  * have one.
2038  */
2039 void  __attribute__((weak)) vmalloc_sync_all(void)
2040 {
2041 }
2042 
2043 
2044 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
2045 {
2046         /* apply_to_page_range() does all the hard work. */
2047         return 0;
2048 }
2049 
2050 /**
2051  *      alloc_vm_area - allocate a range of kernel address space
2052  *      @size:          size of the area
2053  *
2054  *      Returns:        NULL on failure, vm_struct on success
2055  *
2056  *      This function reserves a range of kernel address space, and
2057  *      allocates pagetables to map that range.  No actual mappings
2058  *      are created.  If the kernel address space is not shared
2059  *      between processes, it syncs the pagetable across all
2060  *      processes.
2061  */
2062 struct vm_struct *alloc_vm_area(size_t size)
2063 {
2064         struct vm_struct *area;
2065 
2066         area = get_vm_area_caller(size, VM_IOREMAP,
2067                                 __builtin_return_address(0));
2068         if (area == NULL)
2069                 return NULL;
2070 
2071         /*
2072          * This ensures that page tables are constructed for this region
2073          * of kernel virtual address space and mapped into init_mm.
2074          */
2075         if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
2076                                 area->size, f, NULL)) {
2077                 free_vm_area(area);
2078                 return NULL;
2079         }
2080 
2081         /* Make sure the pagetables are constructed in process kernel
2082            mappings */
2083         vmalloc_sync_all();
2084 
2085         return area;
2086 }
2087 EXPORT_SYMBOL_GPL(alloc_vm_area);
2088 
2089 void free_vm_area(struct vm_struct *area)
2090 {
2091         struct vm_struct *ret;
2092         ret = remove_vm_area(area->addr);
2093         BUG_ON(ret != area);
2094         kfree(area);
2095 }
2096 EXPORT_SYMBOL_GPL(free_vm_area);
2097 
2098 #ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA
2099 static struct vmap_area *node_to_va(struct rb_node *n)
2100 {
2101         return n ? rb_entry(n, struct vmap_area, rb_node) : NULL;
2102 }
2103 
2104 /**
2105  * pvm_find_next_prev - find the next and prev vmap_area surrounding @end
2106  * @end: target address
2107  * @pnext: out arg for the next vmap_area
2108  * @pprev: out arg for the previous vmap_area
2109  *
2110  * Returns: %true if either or both of next and prev are found,
2111  *          %false if no vmap_area exists
2112  *
2113  * Find vmap_areas end addresses of which enclose @end.  ie. if not
2114  * NULL, *pnext->va_end > @end and *pprev->va_end <= @end.
2115  */
2116 static bool pvm_find_next_prev(unsigned long end,
2117                                struct vmap_area **pnext,
2118                                struct vmap_area **pprev)
2119 {
2120         struct rb_node *n = vmap_area_root.rb_node;
2121         struct vmap_area *va = NULL;
2122 
2123         while (n) {
2124                 va = rb_entry(n, struct vmap_area, rb_node);
2125                 if (end < va->va_end)
2126                         n = n->rb_left;
2127                 else if (end > va->va_end)
2128                         n = n->rb_right;
2129                 else
2130                         break;
2131         }
2132 
2133         if (!va)
2134                 return false;
2135 
2136         if (va->va_end > end) {
2137                 *pnext = va;
2138                 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2139         } else {
2140                 *pprev = va;
2141                 *pnext = node_to_va(rb_next(&(*pprev)->rb_node));
2142         }
2143         return true;
2144 }
2145 
2146 /**
2147  * pvm_determine_end - find the highest aligned address between two vmap_areas
2148  * @pnext: in/out arg for the next vmap_area
2149  * @pprev: in/out arg for the previous vmap_area
2150  * @align: alignment
2151  *
2152  * Returns: determined end address
2153  *
2154  * Find the highest aligned address between *@pnext and *@pprev below
2155  * VMALLOC_END.  *@pnext and *@pprev are adjusted so that the aligned
2156  * down address is between the end addresses of the two vmap_areas.
2157  *
2158  * Please note that the address returned by this function may fall
2159  * inside *@pnext vmap_area.  The caller is responsible for checking
2160  * that.
2161  */
2162 static unsigned long pvm_determine_end(struct vmap_area **pnext,
2163                                        struct vmap_area **pprev,
2164                                        unsigned long align)
2165 {
2166         const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2167         unsigned long addr;
2168 
2169         if (*pnext)
2170                 addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end);
2171         else
2172                 addr = vmalloc_end;
2173 
2174         while (*pprev && (*pprev)->va_end > addr) {
2175                 *pnext = *pprev;
2176                 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2177         }
2178 
2179         return addr;
2180 }
2181 
2182 /**
2183  * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
2184  * @offsets: array containing offset of each area
2185  * @sizes: array containing size of each area
2186  * @nr_vms: the number of areas to allocate
2187  * @align: alignment, all entries in @offsets and @sizes must be aligned to this
2188  * @gfp_mask: allocation mask
2189  *
2190  * Returns: kmalloc'd vm_struct pointer array pointing to allocated
2191  *          vm_structs on success, %NULL on failure
2192  *
2193  * Percpu allocator wants to use congruent vm areas so that it can
2194  * maintain the offsets among percpu areas.  This function allocates
2195  * congruent vmalloc areas for it.  These areas tend to be scattered
2196  * pretty far, distance between two areas easily going up to
2197  * gigabytes.  To avoid interacting with regular vmallocs, these areas
2198  * are allocated from top.
2199  *
2200  * Despite its complicated look, this allocator is rather simple.  It
2201  * does everything top-down and scans areas from the end looking for
2202  * matching slot.  While scanning, if any of the areas overlaps with
2203  * existing vmap_area, the base address is pulled down to fit the
2204  * area.  Scanning is repeated till all the areas fit and then all
2205  * necessary data structres are inserted and the result is returned.
2206  */
2207 struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
2208                                      const size_t *sizes, int nr_vms,
2209                                      size_t align, gfp_t gfp_mask)
2210 {
2211         const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
2212         const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2213         struct vmap_area **vas, *prev, *next;
2214         struct vm_struct **vms;
2215         int area, area2, last_area, term_area;
2216         unsigned long base, start, end, last_end;
2217         bool purged = false;
2218 
2219         gfp_mask &= GFP_RECLAIM_MASK;
2220 
2221         /* verify parameters and allocate data structures */
2222         BUG_ON(align & ~PAGE_MASK || !is_power_of_2(align));
2223         for (last_area = 0, area = 0; area < nr_vms; area++) {
2224                 start = offsets[area];
2225                 end = start + sizes[area];
2226 
2227                 /* is everything aligned properly? */
2228                 BUG_ON(!IS_ALIGNED(offsets[area], align));
2229                 BUG_ON(!IS_ALIGNED(sizes[area], align));
2230 
2231                 /* detect the area with the highest address */
2232                 if (start > offsets[last_area])
2233                         last_area = area;
2234 
2235                 for (area2 = 0; area2 < nr_vms; area2++) {
2236                         unsigned long start2 = offsets[area2];
2237                         unsigned long end2 = start2 + sizes[area2];
2238 
2239                         if (area2 == area)
2240                                 continue;
2241 
2242                         BUG_ON(start2 >= start && start2 < end);
2243                         BUG_ON(end2 <= end && end2 > start);
2244                 }
2245         }
2246         last_end = offsets[last_area] + sizes[last_area];
2247 
2248         if (vmalloc_end - vmalloc_start < last_end) {
2249                 WARN_ON(true);
2250                 return NULL;
2251         }
2252 
2253         vms = kzalloc(sizeof(vms[0]) * nr_vms, gfp_mask);
2254         vas = kzalloc(sizeof(vas[0]) * nr_vms, gfp_mask);
2255         if (!vas || !vms)
2256                 goto err_free;
2257 
2258         for (area = 0; area < nr_vms; area++) {
2259                 vas[area] = kzalloc(sizeof(struct vmap_area), gfp_mask);
2260                 vms[area] = kzalloc(sizeof(struct vm_struct), gfp_mask);
2261                 if (!vas[area] || !vms[area])
2262                         goto err_free;
2263         }
2264 retry:
2265         spin_lock(&vmap_area_lock);
2266 
2267         /* start scanning - we scan from the top, begin with the last area */
2268         area = term_area = last_area;
2269         start = offsets[area];
2270         end = start + sizes[area];
2271 
2272         if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) {
2273                 base = vmalloc_end - last_end;
2274                 goto found;
2275         }
2276         base = pvm_determine_end(&next, &prev, align) - end;
2277 
2278         while (true) {
2279                 BUG_ON(next && next->va_end <= base + end);
2280                 BUG_ON(prev && prev->va_end > base + end);
2281 
2282                 /*
2283                  * base might have underflowed, add last_end before
2284                  * comparing.
2285                  */
2286                 if (base + last_end < vmalloc_start + last_end) {
2287                         spin_unlock(&vmap_area_lock);
2288                         if (!purged) {
2289                                 purge_vmap_area_lazy();
2290                                 purged = true;
2291                                 goto retry;
2292                         }
2293                         goto err_free;
2294                 }
2295 
2296                 /*
2297                  * If next overlaps, move base downwards so that it's
2298                  * right below next and then recheck.
2299                  */
2300                 if (next && next->va_start < base + end) {
2301                         base = pvm_determine_end(&next, &prev, align) - end;
2302                         term_area = area;
2303                         continue;
2304                 }
2305 
2306                 /*
2307                  * If prev overlaps, shift down next and prev and move
2308                  * base so that it's right below new next and then
2309                  * recheck.
2310                  */
2311                 if (prev && prev->va_end > base + start)  {
2312                         next = prev;
2313                         prev = node_to_va(rb_prev(&next->rb_node));
2314                         base = pvm_determine_end(&next, &prev, align) - end;
2315                         term_area = area;
2316                         continue;
2317                 }
2318 
2319                 /*
2320                  * This area fits, move on to the previous one.  If
2321                  * the previous one is the terminal one, we're done.
2322                  */
2323                 area = (area + nr_vms - 1) % nr_vms;
2324                 if (area == term_area)
2325                         break;
2326                 start = offsets[area];
2327                 end = start + sizes[area];
2328                 pvm_find_next_prev(base + end, &next, &prev);
2329         }
2330 found:
2331         /* we've found a fitting base, insert all va's */
2332         for (area = 0; area < nr_vms; area++) {
2333                 struct vmap_area *va = vas[area];
2334 
2335                 va->va_start = base + offsets[area];
2336                 va->va_end = va->va_start + sizes[area];
2337                 __insert_vmap_area(va);
2338         }
2339 
2340         vmap_area_pcpu_hole = base + offsets[last_area];
2341 
2342         spin_unlock(&vmap_area_lock);
2343 
2344         /* insert all vm's */
2345         for (area = 0; area < nr_vms; area++)
2346                 insert_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
2347                                   pcpu_get_vm_areas);
2348 
2349         kfree(vas);
2350         return vms;
2351 
2352 err_free:
2353         for (area = 0; area < nr_vms; area++) {
2354                 if (vas)
2355                         kfree(vas[area]);
2356                 if (vms)
2357                         kfree(vms[area]);
2358         }
2359         kfree(vas);
2360         kfree(vms);
2361         return NULL;
2362 }
2363 #endif
2364 
2365 /**
2366  * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
2367  * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
2368  * @nr_vms: the number of allocated areas
2369  *
2370  * Free vm_structs and the array allocated by pcpu_get_vm_areas().
2371  */
2372 void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
2373 {
2374         int i;
2375 
2376         for (i = 0; i < nr_vms; i++)
2377                 free_vm_area(vms[i]);
2378         kfree(vms);
2379 }
2380 
2381 #ifdef CONFIG_PROC_FS
2382 static void *s_start(struct seq_file *m, loff_t *pos)
2383 {
2384         loff_t n = *pos;
2385         struct vm_struct *v;
2386 
2387         read_lock(&vmlist_lock);
2388         v = vmlist;
2389         while (n > 0 && v) {
2390                 n--;
2391                 v = v->next;
2392         }
2393         if (!n)
2394                 return v;
2395 
2396         return NULL;
2397 
2398 }
2399 
2400 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
2401 {
2402         struct vm_struct *v = p;
2403 
2404         ++*pos;
2405         return v->next;
2406 }
2407 
2408 static void s_stop(struct seq_file *m, void *p)
2409 {
2410         read_unlock(&vmlist_lock);
2411 }
2412 
2413 static void show_numa_info(struct seq_file *m, struct vm_struct *v)
2414 {
2415         if (NUMA_BUILD) {
2416                 unsigned int nr, *counters = m->private;
2417 
2418                 if (!counters)
2419                         return;
2420 
2421                 memset(counters, 0, nr_node_ids * sizeof(unsigned int));
2422 
2423                 for (nr = 0; nr < v->nr_pages; nr++)
2424                         counters[page_to_nid(v->pages[nr])]++;
2425 
2426                 for_each_node_state(nr, N_HIGH_MEMORY)
2427                         if (counters[nr])
2428                                 seq_printf(m, " N%u=%u", nr, counters[nr]);
2429         }
2430 }
2431 
2432 static int s_show(struct seq_file *m, void *p)
2433 {
2434         struct vm_struct *v = p;
2435 
2436         seq_printf(m, "0x%p-0x%p %7ld",
2437                 v->addr, v->addr + v->size, v->size);
2438 
2439         if (v->caller) {
2440                 char buff[KSYM_SYMBOL_LEN];
2441 
2442                 seq_putc(m, ' ');
2443                 sprint_symbol(buff, (unsigned long)v->caller);
2444                 seq_puts(m, buff);
2445         }
2446 
2447         if (v->nr_pages)
2448                 seq_printf(m, " pages=%d", v->nr_pages);
2449 
2450         if (v->phys_addr)
2451                 seq_printf(m, " phys=%lx", v->phys_addr);
2452 
2453         if (v->flags & VM_IOREMAP)
2454                 seq_printf(m, " ioremap");
2455 
2456         if (v->flags & VM_ALLOC)
2457                 seq_printf(m, " vmalloc");
2458 
2459         if (v->flags & VM_MAP)
2460                 seq_printf(m, " vmap");
2461 
2462         if (v->flags & VM_USERMAP)
2463                 seq_printf(m, " user");
2464 
2465         if (v->flags & VM_VPAGES)
2466                 seq_printf(m, " vpages");
2467 
2468         show_numa_info(m, v);
2469         seq_putc(m, '\n');
2470         return 0;
2471 }
2472 
2473 static const struct seq_operations vmalloc_op = {
2474         .start = s_start,
2475         .next = s_next,
2476         .stop = s_stop,
2477         .show = s_show,
2478 };
2479 
2480 static int vmalloc_open(struct inode *inode, struct file *file)
2481 {
2482         unsigned int *ptr = NULL;
2483         int ret;
2484 
2485         if (NUMA_BUILD)
2486                 ptr = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL);
2487         ret = seq_open(file, &vmalloc_op);
2488         if (!ret) {
2489                 struct seq_file *m = file->private_data;
2490                 m->private = ptr;
2491         } else
2492                 kfree(ptr);
2493         return ret;
2494 }
2495 
2496 static const struct file_operations proc_vmalloc_operations = {
2497         .open           = vmalloc_open,
2498         .read           = seq_read,
2499         .llseek         = seq_lseek,
2500         .release        = seq_release_private,
2501 };
2502 
2503 static int __init proc_vmalloc_init(void)
2504 {
2505         proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
2506         return 0;
2507 }
2508 module_init(proc_vmalloc_init);
2509 #endif
2510 
2511 

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