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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/mm/vmalloc.c
4 *
5 * Copyright (C) 1993 Linus Torvalds
6 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
7 * SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
8 * Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
9 * Numa awareness, Christoph Lameter, SGI, June 2005
10 * Improving global KVA allocator, Uladzislau Rezki, Sony, May 2019
11 */
12
13#include <linux/vmalloc.h>
14#include <linux/mm.h>
15#include <linux/module.h>
16#include <linux/highmem.h>
17#include <linux/sched/signal.h>
18#include <linux/slab.h>
19#include <linux/spinlock.h>
20#include <linux/interrupt.h>
21#include <linux/proc_fs.h>
22#include <linux/seq_file.h>
23#include <linux/set_memory.h>
24#include <linux/debugobjects.h>
25#include <linux/kallsyms.h>
26#include <linux/list.h>
27#include <linux/notifier.h>
28#include <linux/rbtree.h>
29#include <linux/xarray.h>
30#include <linux/rcupdate.h>
31#include <linux/pfn.h>
32#include <linux/kmemleak.h>
33#include <linux/atomic.h>
34#include <linux/compiler.h>
35#include <linux/llist.h>
36#include <linux/bitops.h>
37#include <linux/rbtree_augmented.h>
38#include <linux/overflow.h>
39
40#include <linux/uaccess.h>
41#include <asm/tlbflush.h>
42#include <asm/shmparam.h>
43
44#include "internal.h"
45#include "pgalloc-track.h"
46
47bool is_vmalloc_addr(const void *x)
48{
49 unsigned long addr = (unsigned long)x;
50
51 return addr >= VMALLOC_START && addr < VMALLOC_END;
52}
53EXPORT_SYMBOL(is_vmalloc_addr);
54
55struct vfree_deferred {
56 struct llist_head list;
57 struct work_struct wq;
58};
59static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
60
61static void __vunmap(const void *, int);
62
63static void free_work(struct work_struct *w)
64{
65 struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
66 struct llist_node *t, *llnode;
67
68 llist_for_each_safe(llnode, t, llist_del_all(&p->list))
69 __vunmap((void *)llnode, 1);
70}
71
72/*** Page table manipulation functions ***/
73
74static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
75 pgtbl_mod_mask *mask)
76{
77 pte_t *pte;
78
79 pte = pte_offset_kernel(pmd, addr);
80 do {
81 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
82 WARN_ON(!pte_none(ptent) && !pte_present(ptent));
83 } while (pte++, addr += PAGE_SIZE, addr != end);
84 *mask |= PGTBL_PTE_MODIFIED;
85}
86
87static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
88 pgtbl_mod_mask *mask)
89{
90 pmd_t *pmd;
91 unsigned long next;
92 int cleared;
93
94 pmd = pmd_offset(pud, addr);
95 do {
96 next = pmd_addr_end(addr, end);
97
98 cleared = pmd_clear_huge(pmd);
99 if (cleared || pmd_bad(*pmd))
100 *mask |= PGTBL_PMD_MODIFIED;
101
102 if (cleared)
103 continue;
104 if (pmd_none_or_clear_bad(pmd))
105 continue;
106 vunmap_pte_range(pmd, addr, next, mask);
107
108 cond_resched();
109 } while (pmd++, addr = next, addr != end);
110}
111
112static void vunmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
113 pgtbl_mod_mask *mask)
114{
115 pud_t *pud;
116 unsigned long next;
117 int cleared;
118
119 pud = pud_offset(p4d, addr);
120 do {
121 next = pud_addr_end(addr, end);
122
123 cleared = pud_clear_huge(pud);
124 if (cleared || pud_bad(*pud))
125 *mask |= PGTBL_PUD_MODIFIED;
126
127 if (cleared)
128 continue;
129 if (pud_none_or_clear_bad(pud))
130 continue;
131 vunmap_pmd_range(pud, addr, next, mask);
132 } while (pud++, addr = next, addr != end);
133}
134
135static void vunmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
136 pgtbl_mod_mask *mask)
137{
138 p4d_t *p4d;
139 unsigned long next;
140 int cleared;
141
142 p4d = p4d_offset(pgd, addr);
143 do {
144 next = p4d_addr_end(addr, end);
145
146 cleared = p4d_clear_huge(p4d);
147 if (cleared || p4d_bad(*p4d))
148 *mask |= PGTBL_P4D_MODIFIED;
149
150 if (cleared)
151 continue;
152 if (p4d_none_or_clear_bad(p4d))
153 continue;
154 vunmap_pud_range(p4d, addr, next, mask);
155 } while (p4d++, addr = next, addr != end);
156}
157
158/**
159 * unmap_kernel_range_noflush - unmap kernel VM area
160 * @start: start of the VM area to unmap
161 * @size: size of the VM area to unmap
162 *
163 * Unmap PFN_UP(@size) pages at @addr. The VM area @addr and @size specify
164 * should have been allocated using get_vm_area() and its friends.
165 *
166 * NOTE:
167 * This function does NOT do any cache flushing. The caller is responsible
168 * for calling flush_cache_vunmap() on to-be-mapped areas before calling this
169 * function and flush_tlb_kernel_range() after.
170 */
171void unmap_kernel_range_noflush(unsigned long start, unsigned long size)
172{
173 unsigned long end = start + size;
174 unsigned long next;
175 pgd_t *pgd;
176 unsigned long addr = start;
177 pgtbl_mod_mask mask = 0;
178
179 BUG_ON(addr >= end);
180 pgd = pgd_offset_k(addr);
181 do {
182 next = pgd_addr_end(addr, end);
183 if (pgd_bad(*pgd))
184 mask |= PGTBL_PGD_MODIFIED;
185 if (pgd_none_or_clear_bad(pgd))
186 continue;
187 vunmap_p4d_range(pgd, addr, next, &mask);
188 } while (pgd++, addr = next, addr != end);
189
190 if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
191 arch_sync_kernel_mappings(start, end);
192}
193
194static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
195 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
196 pgtbl_mod_mask *mask)
197{
198 pte_t *pte;
199
200 /*
201 * nr is a running index into the array which helps higher level
202 * callers keep track of where we're up to.
203 */
204
205 pte = pte_alloc_kernel_track(pmd, addr, mask);
206 if (!pte)
207 return -ENOMEM;
208 do {
209 struct page *page = pages[*nr];
210
211 if (WARN_ON(!pte_none(*pte)))
212 return -EBUSY;
213 if (WARN_ON(!page))
214 return -ENOMEM;
215 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
216 (*nr)++;
217 } while (pte++, addr += PAGE_SIZE, addr != end);
218 *mask |= PGTBL_PTE_MODIFIED;
219 return 0;
220}
221
222static int vmap_pmd_range(pud_t *pud, unsigned long addr,
223 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
224 pgtbl_mod_mask *mask)
225{
226 pmd_t *pmd;
227 unsigned long next;
228
229 pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
230 if (!pmd)
231 return -ENOMEM;
232 do {
233 next = pmd_addr_end(addr, end);
234 if (vmap_pte_range(pmd, addr, next, prot, pages, nr, mask))
235 return -ENOMEM;
236 } while (pmd++, addr = next, addr != end);
237 return 0;
238}
239
240static int vmap_pud_range(p4d_t *p4d, unsigned long addr,
241 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
242 pgtbl_mod_mask *mask)
243{
244 pud_t *pud;
245 unsigned long next;
246
247 pud = pud_alloc_track(&init_mm, p4d, addr, mask);
248 if (!pud)
249 return -ENOMEM;
250 do {
251 next = pud_addr_end(addr, end);
252 if (vmap_pmd_range(pud, addr, next, prot, pages, nr, mask))
253 return -ENOMEM;
254 } while (pud++, addr = next, addr != end);
255 return 0;
256}
257
258static int vmap_p4d_range(pgd_t *pgd, unsigned long addr,
259 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
260 pgtbl_mod_mask *mask)
261{
262 p4d_t *p4d;
263 unsigned long next;
264
265 p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
266 if (!p4d)
267 return -ENOMEM;
268 do {
269 next = p4d_addr_end(addr, end);
270 if (vmap_pud_range(p4d, addr, next, prot, pages, nr, mask))
271 return -ENOMEM;
272 } while (p4d++, addr = next, addr != end);
273 return 0;
274}
275
276/**
277 * map_kernel_range_noflush - map kernel VM area with the specified pages
278 * @addr: start of the VM area to map
279 * @size: size of the VM area to map
280 * @prot: page protection flags to use
281 * @pages: pages to map
282 *
283 * Map PFN_UP(@size) pages at @addr. The VM area @addr and @size specify should
284 * have been allocated using get_vm_area() and its friends.
285 *
286 * NOTE:
287 * This function does NOT do any cache flushing. The caller is responsible for
288 * calling flush_cache_vmap() on to-be-mapped areas before calling this
289 * function.
290 *
291 * RETURNS:
292 * 0 on success, -errno on failure.
293 */
294int map_kernel_range_noflush(unsigned long addr, unsigned long size,
295 pgprot_t prot, struct page **pages)
296{
297 unsigned long start = addr;
298 unsigned long end = addr + size;
299 unsigned long next;
300 pgd_t *pgd;
301 int err = 0;
302 int nr = 0;
303 pgtbl_mod_mask mask = 0;
304
305 BUG_ON(addr >= end);
306 pgd = pgd_offset_k(addr);
307 do {
308 next = pgd_addr_end(addr, end);
309 if (pgd_bad(*pgd))
310 mask |= PGTBL_PGD_MODIFIED;
311 err = vmap_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
312 if (err)
313 return err;
314 } while (pgd++, addr = next, addr != end);
315
316 if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
317 arch_sync_kernel_mappings(start, end);
318
319 return 0;
320}
321
322int map_kernel_range(unsigned long start, unsigned long size, pgprot_t prot,
323 struct page **pages)
324{
325 int ret;
326
327 ret = map_kernel_range_noflush(start, size, prot, pages);
328 flush_cache_vmap(start, start + size);
329 return ret;
330}
331
332int is_vmalloc_or_module_addr(const void *x)
333{
334 /*
335 * ARM, x86-64 and sparc64 put modules in a special place,
336 * and fall back on vmalloc() if that fails. Others
337 * just put it in the vmalloc space.
338 */
339#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
340 unsigned long addr = (unsigned long)x;
341 if (addr >= MODULES_VADDR && addr < MODULES_END)
342 return 1;
343#endif
344 return is_vmalloc_addr(x);
345}
346
347/*
348 * Walk a vmap address to the struct page it maps.
349 */
350struct page *vmalloc_to_page(const void *vmalloc_addr)
351{
352 unsigned long addr = (unsigned long) vmalloc_addr;
353 struct page *page = NULL;
354 pgd_t *pgd = pgd_offset_k(addr);
355 p4d_t *p4d;
356 pud_t *pud;
357 pmd_t *pmd;
358 pte_t *ptep, pte;
359
360 /*
361 * XXX we might need to change this if we add VIRTUAL_BUG_ON for
362 * architectures that do not vmalloc module space
363 */
364 VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
365
366 if (pgd_none(*pgd))
367 return NULL;
368 p4d = p4d_offset(pgd, addr);
369 if (p4d_none(*p4d))
370 return NULL;
371 pud = pud_offset(p4d, addr);
372
373 /*
374 * Don't dereference bad PUD or PMD (below) entries. This will also
375 * identify huge mappings, which we may encounter on architectures
376 * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be
377 * identified as vmalloc addresses by is_vmalloc_addr(), but are
378 * not [unambiguously] associated with a struct page, so there is
379 * no correct value to return for them.
380 */
381 WARN_ON_ONCE(pud_bad(*pud));
382 if (pud_none(*pud) || pud_bad(*pud))
383 return NULL;
384 pmd = pmd_offset(pud, addr);
385 WARN_ON_ONCE(pmd_bad(*pmd));
386 if (pmd_none(*pmd) || pmd_bad(*pmd))
387 return NULL;
388
389 ptep = pte_offset_map(pmd, addr);
390 pte = *ptep;
391 if (pte_present(pte))
392 page = pte_page(pte);
393 pte_unmap(ptep);
394 return page;
395}
396EXPORT_SYMBOL(vmalloc_to_page);
397
398/*
399 * Map a vmalloc()-space virtual address to the physical page frame number.
400 */
401unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
402{
403 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
404}
405EXPORT_SYMBOL(vmalloc_to_pfn);
406
407
408/*** Global kva allocator ***/
409
410#define DEBUG_AUGMENT_PROPAGATE_CHECK 0
411#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
412
413
414static DEFINE_SPINLOCK(vmap_area_lock);
415static DEFINE_SPINLOCK(free_vmap_area_lock);
416/* Export for kexec only */
417LIST_HEAD(vmap_area_list);
418static LLIST_HEAD(vmap_purge_list);
419static struct rb_root vmap_area_root = RB_ROOT;
420static bool vmap_initialized __read_mostly;
421
422/*
423 * This kmem_cache is used for vmap_area objects. Instead of
424 * allocating from slab we reuse an object from this cache to
425 * make things faster. Especially in "no edge" splitting of
426 * free block.
427 */
428static struct kmem_cache *vmap_area_cachep;
429
430/*
431 * This linked list is used in pair with free_vmap_area_root.
432 * It gives O(1) access to prev/next to perform fast coalescing.
433 */
434static LIST_HEAD(free_vmap_area_list);
435
436/*
437 * This augment red-black tree represents the free vmap space.
438 * All vmap_area objects in this tree are sorted by va->va_start
439 * address. It is used for allocation and merging when a vmap
440 * object is released.
441 *
442 * Each vmap_area node contains a maximum available free block
443 * of its sub-tree, right or left. Therefore it is possible to
444 * find a lowest match of free area.
445 */
446static struct rb_root free_vmap_area_root = RB_ROOT;
447
448/*
449 * Preload a CPU with one object for "no edge" split case. The
450 * aim is to get rid of allocations from the atomic context, thus
451 * to use more permissive allocation masks.
452 */
453static DEFINE_PER_CPU(struct vmap_area *, ne_fit_preload_node);
454
455static __always_inline unsigned long
456va_size(struct vmap_area *va)
457{
458 return (va->va_end - va->va_start);
459}
460
461static __always_inline unsigned long
462get_subtree_max_size(struct rb_node *node)
463{
464 struct vmap_area *va;
465
466 va = rb_entry_safe(node, struct vmap_area, rb_node);
467 return va ? va->subtree_max_size : 0;
468}
469
470/*
471 * Gets called when remove the node and rotate.
472 */
473static __always_inline unsigned long
474compute_subtree_max_size(struct vmap_area *va)
475{
476 return max3(va_size(va),
477 get_subtree_max_size(va->rb_node.rb_left),
478 get_subtree_max_size(va->rb_node.rb_right));
479}
480
481RB_DECLARE_CALLBACKS_MAX(static, free_vmap_area_rb_augment_cb,
482 struct vmap_area, rb_node, unsigned long, subtree_max_size, va_size)
483
484static void purge_vmap_area_lazy(void);
485static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
486static unsigned long lazy_max_pages(void);
487
488static atomic_long_t nr_vmalloc_pages;
489
490unsigned long vmalloc_nr_pages(void)
491{
492 return atomic_long_read(&nr_vmalloc_pages);
493}
494
495static struct vmap_area *__find_vmap_area(unsigned long addr)
496{
497 struct rb_node *n = vmap_area_root.rb_node;
498
499 while (n) {
500 struct vmap_area *va;
501
502 va = rb_entry(n, struct vmap_area, rb_node);
503 if (addr < va->va_start)
504 n = n->rb_left;
505 else if (addr >= va->va_end)
506 n = n->rb_right;
507 else
508 return va;
509 }
510
511 return NULL;
512}
513
514/*
515 * This function returns back addresses of parent node
516 * and its left or right link for further processing.
517 *
518 * Otherwise NULL is returned. In that case all further
519 * steps regarding inserting of conflicting overlap range
520 * have to be declined and actually considered as a bug.
521 */
522static __always_inline struct rb_node **
523find_va_links(struct vmap_area *va,
524 struct rb_root *root, struct rb_node *from,
525 struct rb_node **parent)
526{
527 struct vmap_area *tmp_va;
528 struct rb_node **link;
529
530 if (root) {
531 link = &root->rb_node;
532 if (unlikely(!*link)) {
533 *parent = NULL;
534 return link;
535 }
536 } else {
537 link = &from;
538 }
539
540 /*
541 * Go to the bottom of the tree. When we hit the last point
542 * we end up with parent rb_node and correct direction, i name
543 * it link, where the new va->rb_node will be attached to.
544 */
545 do {
546 tmp_va = rb_entry(*link, struct vmap_area, rb_node);
547
548 /*
549 * During the traversal we also do some sanity check.
550 * Trigger the BUG() if there are sides(left/right)
551 * or full overlaps.
552 */
553 if (va->va_start < tmp_va->va_end &&
554 va->va_end <= tmp_va->va_start)
555 link = &(*link)->rb_left;
556 else if (va->va_end > tmp_va->va_start &&
557 va->va_start >= tmp_va->va_end)
558 link = &(*link)->rb_right;
559 else {
560 WARN(1, "vmalloc bug: 0x%lx-0x%lx overlaps with 0x%lx-0x%lx\n",
561 va->va_start, va->va_end, tmp_va->va_start, tmp_va->va_end);
562
563 return NULL;
564 }
565 } while (*link);
566
567 *parent = &tmp_va->rb_node;
568 return link;
569}
570
571static __always_inline struct list_head *
572get_va_next_sibling(struct rb_node *parent, struct rb_node **link)
573{
574 struct list_head *list;
575
576 if (unlikely(!parent))
577 /*
578 * The red-black tree where we try to find VA neighbors
579 * before merging or inserting is empty, i.e. it means
580 * there is no free vmap space. Normally it does not
581 * happen but we handle this case anyway.
582 */
583 return NULL;
584
585 list = &rb_entry(parent, struct vmap_area, rb_node)->list;
586 return (&parent->rb_right == link ? list->next : list);
587}
588
589static __always_inline void
590link_va(struct vmap_area *va, struct rb_root *root,
591 struct rb_node *parent, struct rb_node **link, struct list_head *head)
592{
593 /*
594 * VA is still not in the list, but we can
595 * identify its future previous list_head node.
596 */
597 if (likely(parent)) {
598 head = &rb_entry(parent, struct vmap_area, rb_node)->list;
599 if (&parent->rb_right != link)
600 head = head->prev;
601 }
602
603 /* Insert to the rb-tree */
604 rb_link_node(&va->rb_node, parent, link);
605 if (root == &free_vmap_area_root) {
606 /*
607 * Some explanation here. Just perform simple insertion
608 * to the tree. We do not set va->subtree_max_size to
609 * its current size before calling rb_insert_augmented().
610 * It is because of we populate the tree from the bottom
611 * to parent levels when the node _is_ in the tree.
612 *
613 * Therefore we set subtree_max_size to zero after insertion,
614 * to let __augment_tree_propagate_from() puts everything to
615 * the correct order later on.
616 */
617 rb_insert_augmented(&va->rb_node,
618 root, &free_vmap_area_rb_augment_cb);
619 va->subtree_max_size = 0;
620 } else {
621 rb_insert_color(&va->rb_node, root);
622 }
623
624 /* Address-sort this list */
625 list_add(&va->list, head);
626}
627
628static __always_inline void
629unlink_va(struct vmap_area *va, struct rb_root *root)
630{
631 if (WARN_ON(RB_EMPTY_NODE(&va->rb_node)))
632 return;
633
634 if (root == &free_vmap_area_root)
635 rb_erase_augmented(&va->rb_node,
636 root, &free_vmap_area_rb_augment_cb);
637 else
638 rb_erase(&va->rb_node, root);
639
640 list_del(&va->list);
641 RB_CLEAR_NODE(&va->rb_node);
642}
643
644#if DEBUG_AUGMENT_PROPAGATE_CHECK
645static void
646augment_tree_propagate_check(void)
647{
648 struct vmap_area *va;
649 unsigned long computed_size;
650
651 list_for_each_entry(va, &free_vmap_area_list, list) {
652 computed_size = compute_subtree_max_size(va);
653 if (computed_size != va->subtree_max_size)
654 pr_emerg("tree is corrupted: %lu, %lu\n",
655 va_size(va), va->subtree_max_size);
656 }
657}
658#endif
659
660/*
661 * This function populates subtree_max_size from bottom to upper
662 * levels starting from VA point. The propagation must be done
663 * when VA size is modified by changing its va_start/va_end. Or
664 * in case of newly inserting of VA to the tree.
665 *
666 * It means that __augment_tree_propagate_from() must be called:
667 * - After VA has been inserted to the tree(free path);
668 * - After VA has been shrunk(allocation path);
669 * - After VA has been increased(merging path).
670 *
671 * Please note that, it does not mean that upper parent nodes
672 * and their subtree_max_size are recalculated all the time up
673 * to the root node.
674 *
675 * 4--8
676 * /\
677 * / \
678 * / \
679 * 2--2 8--8
680 *
681 * For example if we modify the node 4, shrinking it to 2, then
682 * no any modification is required. If we shrink the node 2 to 1
683 * its subtree_max_size is updated only, and set to 1. If we shrink
684 * the node 8 to 6, then its subtree_max_size is set to 6 and parent
685 * node becomes 4--6.
686 */
687static __always_inline void
688augment_tree_propagate_from(struct vmap_area *va)
689{
690 /*
691 * Populate the tree from bottom towards the root until
692 * the calculated maximum available size of checked node
693 * is equal to its current one.
694 */
695 free_vmap_area_rb_augment_cb_propagate(&va->rb_node, NULL);
696
697#if DEBUG_AUGMENT_PROPAGATE_CHECK
698 augment_tree_propagate_check();
699#endif
700}
701
702static void
703insert_vmap_area(struct vmap_area *va,
704 struct rb_root *root, struct list_head *head)
705{
706 struct rb_node **link;
707 struct rb_node *parent;
708
709 link = find_va_links(va, root, NULL, &parent);
710 if (link)
711 link_va(va, root, parent, link, head);
712}
713
714static void
715insert_vmap_area_augment(struct vmap_area *va,
716 struct rb_node *from, struct rb_root *root,
717 struct list_head *head)
718{
719 struct rb_node **link;
720 struct rb_node *parent;
721
722 if (from)
723 link = find_va_links(va, NULL, from, &parent);
724 else
725 link = find_va_links(va, root, NULL, &parent);
726
727 if (link) {
728 link_va(va, root, parent, link, head);
729 augment_tree_propagate_from(va);
730 }
731}
732
733/*
734 * Merge de-allocated chunk of VA memory with previous
735 * and next free blocks. If coalesce is not done a new
736 * free area is inserted. If VA has been merged, it is
737 * freed.
738 *
739 * Please note, it can return NULL in case of overlap
740 * ranges, followed by WARN() report. Despite it is a
741 * buggy behaviour, a system can be alive and keep
742 * ongoing.
743 */
744static __always_inline struct vmap_area *
745merge_or_add_vmap_area(struct vmap_area *va,
746 struct rb_root *root, struct list_head *head)
747{
748 struct vmap_area *sibling;
749 struct list_head *next;
750 struct rb_node **link;
751 struct rb_node *parent;
752 bool merged = false;
753
754 /*
755 * Find a place in the tree where VA potentially will be
756 * inserted, unless it is merged with its sibling/siblings.
757 */
758 link = find_va_links(va, root, NULL, &parent);
759 if (!link)
760 return NULL;
761
762 /*
763 * Get next node of VA to check if merging can be done.
764 */
765 next = get_va_next_sibling(parent, link);
766 if (unlikely(next == NULL))
767 goto insert;
768
769 /*
770 * start end
771 * | |
772 * |<------VA------>|<-----Next----->|
773 * | |
774 * start end
775 */
776 if (next != head) {
777 sibling = list_entry(next, struct vmap_area, list);
778 if (sibling->va_start == va->va_end) {
779 sibling->va_start = va->va_start;
780
781 /* Free vmap_area object. */
782 kmem_cache_free(vmap_area_cachep, va);
783
784 /* Point to the new merged area. */
785 va = sibling;
786 merged = true;
787 }
788 }
789
790 /*
791 * start end
792 * | |
793 * |<-----Prev----->|<------VA------>|
794 * | |
795 * start end
796 */
797 if (next->prev != head) {
798 sibling = list_entry(next->prev, struct vmap_area, list);
799 if (sibling->va_end == va->va_start) {
800 /*
801 * If both neighbors are coalesced, it is important
802 * to unlink the "next" node first, followed by merging
803 * with "previous" one. Otherwise the tree might not be
804 * fully populated if a sibling's augmented value is
805 * "normalized" because of rotation operations.
806 */
807 if (merged)
808 unlink_va(va, root);
809
810 sibling->va_end = va->va_end;
811
812 /* Free vmap_area object. */
813 kmem_cache_free(vmap_area_cachep, va);
814
815 /* Point to the new merged area. */
816 va = sibling;
817 merged = true;
818 }
819 }
820
821insert:
822 if (!merged)
823 link_va(va, root, parent, link, head);
824
825 /*
826 * Last step is to check and update the tree.
827 */
828 augment_tree_propagate_from(va);
829 return va;
830}
831
832static __always_inline bool
833is_within_this_va(struct vmap_area *va, unsigned long size,
834 unsigned long align, unsigned long vstart)
835{
836 unsigned long nva_start_addr;
837
838 if (va->va_start > vstart)
839 nva_start_addr = ALIGN(va->va_start, align);
840 else
841 nva_start_addr = ALIGN(vstart, align);
842
843 /* Can be overflowed due to big size or alignment. */
844 if (nva_start_addr + size < nva_start_addr ||
845 nva_start_addr < vstart)
846 return false;
847
848 return (nva_start_addr + size <= va->va_end);
849}
850
851/*
852 * Find the first free block(lowest start address) in the tree,
853 * that will accomplish the request corresponding to passing
854 * parameters.
855 */
856static __always_inline struct vmap_area *
857find_vmap_lowest_match(unsigned long size,
858 unsigned long align, unsigned long vstart)
859{
860 struct vmap_area *va;
861 struct rb_node *node;
862 unsigned long length;
863
864 /* Start from the root. */
865 node = free_vmap_area_root.rb_node;
866
867 /* Adjust the search size for alignment overhead. */
868 length = size + align - 1;
869
870 while (node) {
871 va = rb_entry(node, struct vmap_area, rb_node);
872
873 if (get_subtree_max_size(node->rb_left) >= length &&
874 vstart < va->va_start) {
875 node = node->rb_left;
876 } else {
877 if (is_within_this_va(va, size, align, vstart))
878 return va;
879
880 /*
881 * Does not make sense to go deeper towards the right
882 * sub-tree if it does not have a free block that is
883 * equal or bigger to the requested search length.
884 */
885 if (get_subtree_max_size(node->rb_right) >= length) {
886 node = node->rb_right;
887 continue;
888 }
889
890 /*
891 * OK. We roll back and find the first right sub-tree,
892 * that will satisfy the search criteria. It can happen
893 * only once due to "vstart" restriction.
894 */
895 while ((node = rb_parent(node))) {
896 va = rb_entry(node, struct vmap_area, rb_node);
897 if (is_within_this_va(va, size, align, vstart))
898 return va;
899
900 if (get_subtree_max_size(node->rb_right) >= length &&
901 vstart <= va->va_start) {
902 node = node->rb_right;
903 break;
904 }
905 }
906 }
907 }
908
909 return NULL;
910}
911
912#if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
913#include <linux/random.h>
914
915static struct vmap_area *
916find_vmap_lowest_linear_match(unsigned long size,
917 unsigned long align, unsigned long vstart)
918{
919 struct vmap_area *va;
920
921 list_for_each_entry(va, &free_vmap_area_list, list) {
922 if (!is_within_this_va(va, size, align, vstart))
923 continue;
924
925 return va;
926 }
927
928 return NULL;
929}
930
931static void
932find_vmap_lowest_match_check(unsigned long size)
933{
934 struct vmap_area *va_1, *va_2;
935 unsigned long vstart;
936 unsigned int rnd;
937
938 get_random_bytes(&rnd, sizeof(rnd));
939 vstart = VMALLOC_START + rnd;
940
941 va_1 = find_vmap_lowest_match(size, 1, vstart);
942 va_2 = find_vmap_lowest_linear_match(size, 1, vstart);
943
944 if (va_1 != va_2)
945 pr_emerg("not lowest: t: 0x%p, l: 0x%p, v: 0x%lx\n",
946 va_1, va_2, vstart);
947}
948#endif
949
950enum fit_type {
951 NOTHING_FIT = 0,
952 FL_FIT_TYPE = 1, /* full fit */
953 LE_FIT_TYPE = 2, /* left edge fit */
954 RE_FIT_TYPE = 3, /* right edge fit */
955 NE_FIT_TYPE = 4 /* no edge fit */
956};
957
958static __always_inline enum fit_type
959classify_va_fit_type(struct vmap_area *va,
960 unsigned long nva_start_addr, unsigned long size)
961{
962 enum fit_type type;
963
964 /* Check if it is within VA. */
965 if (nva_start_addr < va->va_start ||
966 nva_start_addr + size > va->va_end)
967 return NOTHING_FIT;
968
969 /* Now classify. */
970 if (va->va_start == nva_start_addr) {
971 if (va->va_end == nva_start_addr + size)
972 type = FL_FIT_TYPE;
973 else
974 type = LE_FIT_TYPE;
975 } else if (va->va_end == nva_start_addr + size) {
976 type = RE_FIT_TYPE;
977 } else {
978 type = NE_FIT_TYPE;
979 }
980
981 return type;
982}
983
984static __always_inline int
985adjust_va_to_fit_type(struct vmap_area *va,
986 unsigned long nva_start_addr, unsigned long size,
987 enum fit_type type)
988{
989 struct vmap_area *lva = NULL;
990
991 if (type == FL_FIT_TYPE) {
992 /*
993 * No need to split VA, it fully fits.
994 *
995 * | |
996 * V NVA V
997 * |---------------|
998 */
999 unlink_va(va, &free_vmap_area_root);
1000 kmem_cache_free(vmap_area_cachep, va);
1001 } else if (type == LE_FIT_TYPE) {
1002 /*
1003 * Split left edge of fit VA.
1004 *
1005 * | |
1006 * V NVA V R
1007 * |-------|-------|
1008 */
1009 va->va_start += size;
1010 } else if (type == RE_FIT_TYPE) {
1011 /*
1012 * Split right edge of fit VA.
1013 *
1014 * | |
1015 * L V NVA V
1016 * |-------|-------|
1017 */
1018 va->va_end = nva_start_addr;
1019 } else if (type == NE_FIT_TYPE) {
1020 /*
1021 * Split no edge of fit VA.
1022 *
1023 * | |
1024 * L V NVA V R
1025 * |---|-------|---|
1026 */
1027 lva = __this_cpu_xchg(ne_fit_preload_node, NULL);
1028 if (unlikely(!lva)) {
1029 /*
1030 * For percpu allocator we do not do any pre-allocation
1031 * and leave it as it is. The reason is it most likely
1032 * never ends up with NE_FIT_TYPE splitting. In case of
1033 * percpu allocations offsets and sizes are aligned to
1034 * fixed align request, i.e. RE_FIT_TYPE and FL_FIT_TYPE
1035 * are its main fitting cases.
1036 *
1037 * There are a few exceptions though, as an example it is
1038 * a first allocation (early boot up) when we have "one"
1039 * big free space that has to be split.
1040 *
1041 * Also we can hit this path in case of regular "vmap"
1042 * allocations, if "this" current CPU was not preloaded.
1043 * See the comment in alloc_vmap_area() why. If so, then
1044 * GFP_NOWAIT is used instead to get an extra object for
1045 * split purpose. That is rare and most time does not
1046 * occur.
1047 *
1048 * What happens if an allocation gets failed. Basically,
1049 * an "overflow" path is triggered to purge lazily freed
1050 * areas to free some memory, then, the "retry" path is
1051 * triggered to repeat one more time. See more details
1052 * in alloc_vmap_area() function.
1053 */
1054 lva = kmem_cache_alloc(vmap_area_cachep, GFP_NOWAIT);
1055 if (!lva)
1056 return -1;
1057 }
1058
1059 /*
1060 * Build the remainder.
1061 */
1062 lva->va_start = va->va_start;
1063 lva->va_end = nva_start_addr;
1064
1065 /*
1066 * Shrink this VA to remaining size.
1067 */
1068 va->va_start = nva_start_addr + size;
1069 } else {
1070 return -1;
1071 }
1072
1073 if (type != FL_FIT_TYPE) {
1074 augment_tree_propagate_from(va);
1075
1076 if (lva) /* type == NE_FIT_TYPE */
1077 insert_vmap_area_augment(lva, &va->rb_node,
1078 &free_vmap_area_root, &free_vmap_area_list);
1079 }
1080
1081 return 0;
1082}
1083
1084/*
1085 * Returns a start address of the newly allocated area, if success.
1086 * Otherwise a vend is returned that indicates failure.
1087 */
1088static __always_inline unsigned long
1089__alloc_vmap_area(unsigned long size, unsigned long align,
1090 unsigned long vstart, unsigned long vend)
1091{
1092 unsigned long nva_start_addr;
1093 struct vmap_area *va;
1094 enum fit_type type;
1095 int ret;
1096
1097 va = find_vmap_lowest_match(size, align, vstart);
1098 if (unlikely(!va))
1099 return vend;
1100
1101 if (va->va_start > vstart)
1102 nva_start_addr = ALIGN(va->va_start, align);
1103 else
1104 nva_start_addr = ALIGN(vstart, align);
1105
1106 /* Check the "vend" restriction. */
1107 if (nva_start_addr + size > vend)
1108 return vend;
1109
1110 /* Classify what we have found. */
1111 type = classify_va_fit_type(va, nva_start_addr, size);
1112 if (WARN_ON_ONCE(type == NOTHING_FIT))
1113 return vend;
1114
1115 /* Update the free vmap_area. */
1116 ret = adjust_va_to_fit_type(va, nva_start_addr, size, type);
1117 if (ret)
1118 return vend;
1119
1120#if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
1121 find_vmap_lowest_match_check(size);
1122#endif
1123
1124 return nva_start_addr;
1125}
1126
1127/*
1128 * Free a region of KVA allocated by alloc_vmap_area
1129 */
1130static void free_vmap_area(struct vmap_area *va)
1131{
1132 /*
1133 * Remove from the busy tree/list.
1134 */
1135 spin_lock(&vmap_area_lock);
1136 unlink_va(va, &vmap_area_root);
1137 spin_unlock(&vmap_area_lock);
1138
1139 /*
1140 * Insert/Merge it back to the free tree/list.
1141 */
1142 spin_lock(&free_vmap_area_lock);
1143 merge_or_add_vmap_area(va, &free_vmap_area_root, &free_vmap_area_list);
1144 spin_unlock(&free_vmap_area_lock);
1145}
1146
1147/*
1148 * Allocate a region of KVA of the specified size and alignment, within the
1149 * vstart and vend.
1150 */
1151static struct vmap_area *alloc_vmap_area(unsigned long size,
1152 unsigned long align,
1153 unsigned long vstart, unsigned long vend,
1154 int node, gfp_t gfp_mask)
1155{
1156 struct vmap_area *va, *pva;
1157 unsigned long addr;
1158 int purged = 0;
1159 int ret;
1160
1161 BUG_ON(!size);
1162 BUG_ON(offset_in_page(size));
1163 BUG_ON(!is_power_of_2(align));
1164
1165 if (unlikely(!vmap_initialized))
1166 return ERR_PTR(-EBUSY);
1167
1168 might_sleep();
1169 gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
1170
1171 va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
1172 if (unlikely(!va))
1173 return ERR_PTR(-ENOMEM);
1174
1175 /*
1176 * Only scan the relevant parts containing pointers to other objects
1177 * to avoid false negatives.
1178 */
1179 kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask);
1180
1181retry:
1182 /*
1183 * Preload this CPU with one extra vmap_area object. It is used
1184 * when fit type of free area is NE_FIT_TYPE. Please note, it
1185 * does not guarantee that an allocation occurs on a CPU that
1186 * is preloaded, instead we minimize the case when it is not.
1187 * It can happen because of cpu migration, because there is a
1188 * race until the below spinlock is taken.
1189 *
1190 * The preload is done in non-atomic context, thus it allows us
1191 * to use more permissive allocation masks to be more stable under
1192 * low memory condition and high memory pressure. In rare case,
1193 * if not preloaded, GFP_NOWAIT is used.
1194 *
1195 * Set "pva" to NULL here, because of "retry" path.
1196 */
1197 pva = NULL;
1198
1199 if (!this_cpu_read(ne_fit_preload_node))
1200 /*
1201 * Even if it fails we do not really care about that.
1202 * Just proceed as it is. If needed "overflow" path
1203 * will refill the cache we allocate from.
1204 */
1205 pva = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
1206
1207 spin_lock(&free_vmap_area_lock);
1208
1209 if (pva && __this_cpu_cmpxchg(ne_fit_preload_node, NULL, pva))
1210 kmem_cache_free(vmap_area_cachep, pva);
1211
1212 /*
1213 * If an allocation fails, the "vend" address is
1214 * returned. Therefore trigger the overflow path.
1215 */
1216 addr = __alloc_vmap_area(size, align, vstart, vend);
1217 spin_unlock(&free_vmap_area_lock);
1218
1219 if (unlikely(addr == vend))
1220 goto overflow;
1221
1222 va->va_start = addr;
1223 va->va_end = addr + size;
1224 va->vm = NULL;
1225
1226
1227 spin_lock(&vmap_area_lock);
1228 insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
1229 spin_unlock(&vmap_area_lock);
1230
1231 BUG_ON(!IS_ALIGNED(va->va_start, align));
1232 BUG_ON(va->va_start < vstart);
1233 BUG_ON(va->va_end > vend);
1234
1235 ret = kasan_populate_vmalloc(addr, size);
1236 if (ret) {
1237 free_vmap_area(va);
1238 return ERR_PTR(ret);
1239 }
1240
1241 return va;
1242
1243overflow:
1244 if (!purged) {
1245 purge_vmap_area_lazy();
1246 purged = 1;
1247 goto retry;
1248 }
1249
1250 if (gfpflags_allow_blocking(gfp_mask)) {
1251 unsigned long freed = 0;
1252 blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
1253 if (freed > 0) {
1254 purged = 0;
1255 goto retry;
1256 }
1257 }
1258
1259 if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
1260 pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
1261 size);
1262
1263 kmem_cache_free(vmap_area_cachep, va);
1264 return ERR_PTR(-EBUSY);
1265}
1266
1267int register_vmap_purge_notifier(struct notifier_block *nb)
1268{
1269 return blocking_notifier_chain_register(&vmap_notify_list, nb);
1270}
1271EXPORT_SYMBOL_GPL(register_vmap_purge_notifier);
1272
1273int unregister_vmap_purge_notifier(struct notifier_block *nb)
1274{
1275 return blocking_notifier_chain_unregister(&vmap_notify_list, nb);
1276}
1277EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier);
1278
1279/*
1280 * lazy_max_pages is the maximum amount of virtual address space we gather up
1281 * before attempting to purge with a TLB flush.
1282 *
1283 * There is a tradeoff here: a larger number will cover more kernel page tables
1284 * and take slightly longer to purge, but it will linearly reduce the number of
1285 * global TLB flushes that must be performed. It would seem natural to scale
1286 * this number up linearly with the number of CPUs (because vmapping activity
1287 * could also scale linearly with the number of CPUs), however it is likely
1288 * that in practice, workloads might be constrained in other ways that mean
1289 * vmap activity will not scale linearly with CPUs. Also, I want to be
1290 * conservative and not introduce a big latency on huge systems, so go with
1291 * a less aggressive log scale. It will still be an improvement over the old
1292 * code, and it will be simple to change the scale factor if we find that it
1293 * becomes a problem on bigger systems.
1294 */
1295static unsigned long lazy_max_pages(void)
1296{
1297 unsigned int log;
1298
1299 log = fls(num_online_cpus());
1300
1301 return log * (32UL * 1024 * 1024 / PAGE_SIZE);
1302}
1303
1304static atomic_long_t vmap_lazy_nr = ATOMIC_LONG_INIT(0);
1305
1306/*
1307 * Serialize vmap purging. There is no actual criticial section protected
1308 * by this look, but we want to avoid concurrent calls for performance
1309 * reasons and to make the pcpu_get_vm_areas more deterministic.
1310 */
1311static DEFINE_MUTEX(vmap_purge_lock);
1312
1313/* for per-CPU blocks */
1314static void purge_fragmented_blocks_allcpus(void);
1315
1316/*
1317 * called before a call to iounmap() if the caller wants vm_area_struct's
1318 * immediately freed.
1319 */
1320void set_iounmap_nonlazy(void)
1321{
1322 atomic_long_set(&vmap_lazy_nr, lazy_max_pages()+1);
1323}
1324
1325/*
1326 * Purges all lazily-freed vmap areas.
1327 */
1328static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
1329{
1330 unsigned long resched_threshold;
1331 struct llist_node *valist;
1332 struct vmap_area *va;
1333 struct vmap_area *n_va;
1334
1335 lockdep_assert_held(&vmap_purge_lock);
1336
1337 valist = llist_del_all(&vmap_purge_list);
1338 if (unlikely(valist == NULL))
1339 return false;
1340
1341 /*
1342 * TODO: to calculate a flush range without looping.
1343 * The list can be up to lazy_max_pages() elements.
1344 */
1345 llist_for_each_entry(va, valist, purge_list) {
1346 if (va->va_start < start)
1347 start = va->va_start;
1348 if (va->va_end > end)
1349 end = va->va_end;
1350 }
1351
1352 flush_tlb_kernel_range(start, end);
1353 resched_threshold = lazy_max_pages() << 1;
1354
1355 spin_lock(&free_vmap_area_lock);
1356 llist_for_each_entry_safe(va, n_va, valist, purge_list) {
1357 unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
1358 unsigned long orig_start = va->va_start;
1359 unsigned long orig_end = va->va_end;
1360
1361 /*
1362 * Finally insert or merge lazily-freed area. It is
1363 * detached and there is no need to "unlink" it from
1364 * anything.
1365 */
1366 va = merge_or_add_vmap_area(va, &free_vmap_area_root,
1367 &free_vmap_area_list);
1368
1369 if (!va)
1370 continue;
1371
1372 if (is_vmalloc_or_module_addr((void *)orig_start))
1373 kasan_release_vmalloc(orig_start, orig_end,
1374 va->va_start, va->va_end);
1375
1376 atomic_long_sub(nr, &vmap_lazy_nr);
1377
1378 if (atomic_long_read(&vmap_lazy_nr) < resched_threshold)
1379 cond_resched_lock(&free_vmap_area_lock);
1380 }
1381 spin_unlock(&free_vmap_area_lock);
1382 return true;
1383}
1384
1385/*
1386 * Kick off a purge of the outstanding lazy areas. Don't bother if somebody
1387 * is already purging.
1388 */
1389static void try_purge_vmap_area_lazy(void)
1390{
1391 if (mutex_trylock(&vmap_purge_lock)) {
1392 __purge_vmap_area_lazy(ULONG_MAX, 0);
1393 mutex_unlock(&vmap_purge_lock);
1394 }
1395}
1396
1397/*
1398 * Kick off a purge of the outstanding lazy areas.
1399 */
1400static void purge_vmap_area_lazy(void)
1401{
1402 mutex_lock(&vmap_purge_lock);
1403 purge_fragmented_blocks_allcpus();
1404 __purge_vmap_area_lazy(ULONG_MAX, 0);
1405 mutex_unlock(&vmap_purge_lock);
1406}
1407
1408/*
1409 * Free a vmap area, caller ensuring that the area has been unmapped
1410 * and flush_cache_vunmap had been called for the correct range
1411 * previously.
1412 */
1413static void free_vmap_area_noflush(struct vmap_area *va)
1414{
1415 unsigned long nr_lazy;
1416
1417 spin_lock(&vmap_area_lock);
1418 unlink_va(va, &vmap_area_root);
1419 spin_unlock(&vmap_area_lock);
1420
1421 nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
1422 PAGE_SHIFT, &vmap_lazy_nr);
1423
1424 /* After this point, we may free va at any time */
1425 llist_add(&va->purge_list, &vmap_purge_list);
1426
1427 if (unlikely(nr_lazy > lazy_max_pages()))
1428 try_purge_vmap_area_lazy();
1429}
1430
1431/*
1432 * Free and unmap a vmap area
1433 */
1434static void free_unmap_vmap_area(struct vmap_area *va)
1435{
1436 flush_cache_vunmap(va->va_start, va->va_end);
1437 unmap_kernel_range_noflush(va->va_start, va->va_end - va->va_start);
1438 if (debug_pagealloc_enabled_static())
1439 flush_tlb_kernel_range(va->va_start, va->va_end);
1440
1441 free_vmap_area_noflush(va);
1442}
1443
1444static struct vmap_area *find_vmap_area(unsigned long addr)
1445{
1446 struct vmap_area *va;
1447
1448 spin_lock(&vmap_area_lock);
1449 va = __find_vmap_area(addr);
1450 spin_unlock(&vmap_area_lock);
1451
1452 return va;
1453}
1454
1455/*** Per cpu kva allocator ***/
1456
1457/*
1458 * vmap space is limited especially on 32 bit architectures. Ensure there is
1459 * room for at least 16 percpu vmap blocks per CPU.
1460 */
1461/*
1462 * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
1463 * to #define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START). Guess
1464 * instead (we just need a rough idea)
1465 */
1466#if BITS_PER_LONG == 32
1467#define VMALLOC_SPACE (128UL*1024*1024)
1468#else
1469#define VMALLOC_SPACE (128UL*1024*1024*1024)
1470#endif
1471
1472#define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE)
1473#define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */
1474#define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */
1475#define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2)
1476#define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */
1477#define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */
1478#define VMAP_BBMAP_BITS \
1479 VMAP_MIN(VMAP_BBMAP_BITS_MAX, \
1480 VMAP_MAX(VMAP_BBMAP_BITS_MIN, \
1481 VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
1482
1483#define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
1484
1485struct vmap_block_queue {
1486 spinlock_t lock;
1487 struct list_head free;
1488};
1489
1490struct vmap_block {
1491 spinlock_t lock;
1492 struct vmap_area *va;
1493 unsigned long free, dirty;
1494 unsigned long dirty_min, dirty_max; /*< dirty range */
1495 struct list_head free_list;
1496 struct rcu_head rcu_head;
1497 struct list_head purge;
1498};
1499
1500/* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
1501static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
1502
1503/*
1504 * XArray of vmap blocks, indexed by address, to quickly find a vmap block
1505 * in the free path. Could get rid of this if we change the API to return a
1506 * "cookie" from alloc, to be passed to free. But no big deal yet.
1507 */
1508static DEFINE_XARRAY(vmap_blocks);
1509
1510/*
1511 * We should probably have a fallback mechanism to allocate virtual memory
1512 * out of partially filled vmap blocks. However vmap block sizing should be
1513 * fairly reasonable according to the vmalloc size, so it shouldn't be a
1514 * big problem.
1515 */
1516
1517static unsigned long addr_to_vb_idx(unsigned long addr)
1518{
1519 addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
1520 addr /= VMAP_BLOCK_SIZE;
1521 return addr;
1522}
1523
1524static void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off)
1525{
1526 unsigned long addr;
1527
1528 addr = va_start + (pages_off << PAGE_SHIFT);
1529 BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(va_start));
1530 return (void *)addr;
1531}
1532
1533/**
1534 * new_vmap_block - allocates new vmap_block and occupies 2^order pages in this
1535 * block. Of course pages number can't exceed VMAP_BBMAP_BITS
1536 * @order: how many 2^order pages should be occupied in newly allocated block
1537 * @gfp_mask: flags for the page level allocator
1538 *
1539 * Return: virtual address in a newly allocated block or ERR_PTR(-errno)
1540 */
1541static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
1542{
1543 struct vmap_block_queue *vbq;
1544 struct vmap_block *vb;
1545 struct vmap_area *va;
1546 unsigned long vb_idx;
1547 int node, err;
1548 void *vaddr;
1549
1550 node = numa_node_id();
1551
1552 vb = kmalloc_node(sizeof(struct vmap_block),
1553 gfp_mask & GFP_RECLAIM_MASK, node);
1554 if (unlikely(!vb))
1555 return ERR_PTR(-ENOMEM);
1556
1557 va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
1558 VMALLOC_START, VMALLOC_END,
1559 node, gfp_mask);
1560 if (IS_ERR(va)) {
1561 kfree(vb);
1562 return ERR_CAST(va);
1563 }
1564
1565 vaddr = vmap_block_vaddr(va->va_start, 0);
1566 spin_lock_init(&vb->lock);
1567 vb->va = va;
1568 /* At least something should be left free */
1569 BUG_ON(VMAP_BBMAP_BITS <= (1UL << order));
1570 vb->free = VMAP_BBMAP_BITS - (1UL << order);
1571 vb->dirty = 0;
1572 vb->dirty_min = VMAP_BBMAP_BITS;
1573 vb->dirty_max = 0;
1574 INIT_LIST_HEAD(&vb->free_list);
1575
1576 vb_idx = addr_to_vb_idx(va->va_start);
1577 err = xa_insert(&vmap_blocks, vb_idx, vb, gfp_mask);
1578 if (err) {
1579 kfree(vb);
1580 free_vmap_area(va);
1581 return ERR_PTR(err);
1582 }
1583
1584 vbq = &get_cpu_var(vmap_block_queue);
1585 spin_lock(&vbq->lock);
1586 list_add_tail_rcu(&vb->free_list, &vbq->free);
1587 spin_unlock(&vbq->lock);
1588 put_cpu_var(vmap_block_queue);
1589
1590 return vaddr;
1591}
1592
1593static void free_vmap_block(struct vmap_block *vb)
1594{
1595 struct vmap_block *tmp;
1596
1597 tmp = xa_erase(&vmap_blocks, addr_to_vb_idx(vb->va->va_start));
1598 BUG_ON(tmp != vb);
1599
1600 free_vmap_area_noflush(vb->va);
1601 kfree_rcu(vb, rcu_head);
1602}
1603
1604static void purge_fragmented_blocks(int cpu)
1605{
1606 LIST_HEAD(purge);
1607 struct vmap_block *vb;
1608 struct vmap_block *n_vb;
1609 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
1610
1611 rcu_read_lock();
1612 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1613
1614 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
1615 continue;
1616
1617 spin_lock(&vb->lock);
1618 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
1619 vb->free = 0; /* prevent further allocs after releasing lock */
1620 vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
1621 vb->dirty_min = 0;
1622 vb->dirty_max = VMAP_BBMAP_BITS;
1623 spin_lock(&vbq->lock);
1624 list_del_rcu(&vb->free_list);
1625 spin_unlock(&vbq->lock);
1626 spin_unlock(&vb->lock);
1627 list_add_tail(&vb->purge, &purge);
1628 } else
1629 spin_unlock(&vb->lock);
1630 }
1631 rcu_read_unlock();
1632
1633 list_for_each_entry_safe(vb, n_vb, &purge, purge) {
1634 list_del(&vb->purge);
1635 free_vmap_block(vb);
1636 }
1637}
1638
1639static void purge_fragmented_blocks_allcpus(void)
1640{
1641 int cpu;
1642
1643 for_each_possible_cpu(cpu)
1644 purge_fragmented_blocks(cpu);
1645}
1646
1647static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
1648{
1649 struct vmap_block_queue *vbq;
1650 struct vmap_block *vb;
1651 void *vaddr = NULL;
1652 unsigned int order;
1653
1654 BUG_ON(offset_in_page(size));
1655 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
1656 if (WARN_ON(size == 0)) {
1657 /*
1658 * Allocating 0 bytes isn't what caller wants since
1659 * get_order(0) returns funny result. Just warn and terminate
1660 * early.
1661 */
1662 return NULL;
1663 }
1664 order = get_order(size);
1665
1666 rcu_read_lock();
1667 vbq = &get_cpu_var(vmap_block_queue);
1668 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1669 unsigned long pages_off;
1670
1671 spin_lock(&vb->lock);
1672 if (vb->free < (1UL << order)) {
1673 spin_unlock(&vb->lock);
1674 continue;
1675 }
1676
1677 pages_off = VMAP_BBMAP_BITS - vb->free;
1678 vaddr = vmap_block_vaddr(vb->va->va_start, pages_off);
1679 vb->free -= 1UL << order;
1680 if (vb->free == 0) {
1681 spin_lock(&vbq->lock);
1682 list_del_rcu(&vb->free_list);
1683 spin_unlock(&vbq->lock);
1684 }
1685
1686 spin_unlock(&vb->lock);
1687 break;
1688 }
1689
1690 put_cpu_var(vmap_block_queue);
1691 rcu_read_unlock();
1692
1693 /* Allocate new block if nothing was found */
1694 if (!vaddr)
1695 vaddr = new_vmap_block(order, gfp_mask);
1696
1697 return vaddr;
1698}
1699
1700static void vb_free(unsigned long addr, unsigned long size)
1701{
1702 unsigned long offset;
1703 unsigned int order;
1704 struct vmap_block *vb;
1705
1706 BUG_ON(offset_in_page(size));
1707 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
1708
1709 flush_cache_vunmap(addr, addr + size);
1710
1711 order = get_order(size);
1712 offset = (addr & (VMAP_BLOCK_SIZE - 1)) >> PAGE_SHIFT;
1713 vb = xa_load(&vmap_blocks, addr_to_vb_idx(addr));
1714
1715 unmap_kernel_range_noflush(addr, size);
1716
1717 if (debug_pagealloc_enabled_static())
1718 flush_tlb_kernel_range(addr, addr + size);
1719
1720 spin_lock(&vb->lock);
1721
1722 /* Expand dirty range */
1723 vb->dirty_min = min(vb->dirty_min, offset);
1724 vb->dirty_max = max(vb->dirty_max, offset + (1UL << order));
1725
1726 vb->dirty += 1UL << order;
1727 if (vb->dirty == VMAP_BBMAP_BITS) {
1728 BUG_ON(vb->free);
1729 spin_unlock(&vb->lock);
1730 free_vmap_block(vb);
1731 } else
1732 spin_unlock(&vb->lock);
1733}
1734
1735static void _vm_unmap_aliases(unsigned long start, unsigned long end, int flush)
1736{
1737 int cpu;
1738
1739 if (unlikely(!vmap_initialized))
1740 return;
1741
1742 might_sleep();
1743
1744 for_each_possible_cpu(cpu) {
1745 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
1746 struct vmap_block *vb;
1747
1748 rcu_read_lock();
1749 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1750 spin_lock(&vb->lock);
1751 if (vb->dirty) {
1752 unsigned long va_start = vb->va->va_start;
1753 unsigned long s, e;
1754
1755 s = va_start + (vb->dirty_min << PAGE_SHIFT);
1756 e = va_start + (vb->dirty_max << PAGE_SHIFT);
1757
1758 start = min(s, start);
1759 end = max(e, end);
1760
1761 flush = 1;
1762 }
1763 spin_unlock(&vb->lock);
1764 }
1765 rcu_read_unlock();
1766 }
1767
1768 mutex_lock(&vmap_purge_lock);
1769 purge_fragmented_blocks_allcpus();
1770 if (!__purge_vmap_area_lazy(start, end) && flush)
1771 flush_tlb_kernel_range(start, end);
1772 mutex_unlock(&vmap_purge_lock);
1773}
1774
1775/**
1776 * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
1777 *
1778 * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
1779 * to amortize TLB flushing overheads. What this means is that any page you
1780 * have now, may, in a former life, have been mapped into kernel virtual
1781 * address by the vmap layer and so there might be some CPUs with TLB entries
1782 * still referencing that page (additional to the regular 1:1 kernel mapping).
1783 *
1784 * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
1785 * be sure that none of the pages we have control over will have any aliases
1786 * from the vmap layer.
1787 */
1788void vm_unmap_aliases(void)
1789{
1790 unsigned long start = ULONG_MAX, end = 0;
1791 int flush = 0;
1792
1793 _vm_unmap_aliases(start, end, flush);
1794}
1795EXPORT_SYMBOL_GPL(vm_unmap_aliases);
1796
1797/**
1798 * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
1799 * @mem: the pointer returned by vm_map_ram
1800 * @count: the count passed to that vm_map_ram call (cannot unmap partial)
1801 */
1802void vm_unmap_ram(const void *mem, unsigned int count)
1803{
1804 unsigned long size = (unsigned long)count << PAGE_SHIFT;
1805 unsigned long addr = (unsigned long)mem;
1806 struct vmap_area *va;
1807
1808 might_sleep();
1809 BUG_ON(!addr);
1810 BUG_ON(addr < VMALLOC_START);
1811 BUG_ON(addr > VMALLOC_END);
1812 BUG_ON(!PAGE_ALIGNED(addr));
1813
1814 kasan_poison_vmalloc(mem, size);
1815
1816 if (likely(count <= VMAP_MAX_ALLOC)) {
1817 debug_check_no_locks_freed(mem, size);
1818 vb_free(addr, size);
1819 return;
1820 }
1821
1822 va = find_vmap_area(addr);
1823 BUG_ON(!va);
1824 debug_check_no_locks_freed((void *)va->va_start,
1825 (va->va_end - va->va_start));
1826 free_unmap_vmap_area(va);
1827}
1828EXPORT_SYMBOL(vm_unmap_ram);
1829
1830/**
1831 * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
1832 * @pages: an array of pointers to the pages to be mapped
1833 * @count: number of pages
1834 * @node: prefer to allocate data structures on this node
1835 *
1836 * If you use this function for less than VMAP_MAX_ALLOC pages, it could be
1837 * faster than vmap so it's good. But if you mix long-life and short-life
1838 * objects with vm_map_ram(), it could consume lots of address space through
1839 * fragmentation (especially on a 32bit machine). You could see failures in
1840 * the end. Please use this function for short-lived objects.
1841 *
1842 * Returns: a pointer to the address that has been mapped, or %NULL on failure
1843 */
1844void *vm_map_ram(struct page **pages, unsigned int count, int node)
1845{
1846 unsigned long size = (unsigned long)count << PAGE_SHIFT;
1847 unsigned long addr;
1848 void *mem;
1849
1850 if (likely(count <= VMAP_MAX_ALLOC)) {
1851 mem = vb_alloc(size, GFP_KERNEL);
1852 if (IS_ERR(mem))
1853 return NULL;
1854 addr = (unsigned long)mem;
1855 } else {
1856 struct vmap_area *va;
1857 va = alloc_vmap_area(size, PAGE_SIZE,
1858 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
1859 if (IS_ERR(va))
1860 return NULL;
1861
1862 addr = va->va_start;
1863 mem = (void *)addr;
1864 }
1865
1866 kasan_unpoison_vmalloc(mem, size);
1867
1868 if (map_kernel_range(addr, size, PAGE_KERNEL, pages) < 0) {
1869 vm_unmap_ram(mem, count);
1870 return NULL;
1871 }
1872 return mem;
1873}
1874EXPORT_SYMBOL(vm_map_ram);
1875
1876static struct vm_struct *vmlist __initdata;
1877
1878/**
1879 * vm_area_add_early - add vmap area early during boot
1880 * @vm: vm_struct to add
1881 *
1882 * This function is used to add fixed kernel vm area to vmlist before
1883 * vmalloc_init() is called. @vm->addr, @vm->size, and @vm->flags
1884 * should contain proper values and the other fields should be zero.
1885 *
1886 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1887 */
1888void __init vm_area_add_early(struct vm_struct *vm)
1889{
1890 struct vm_struct *tmp, **p;
1891
1892 BUG_ON(vmap_initialized);
1893 for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1894 if (tmp->addr >= vm->addr) {
1895 BUG_ON(tmp->addr < vm->addr + vm->size);
1896 break;
1897 } else
1898 BUG_ON(tmp->addr + tmp->size > vm->addr);
1899 }
1900 vm->next = *p;
1901 *p = vm;
1902}
1903
1904/**
1905 * vm_area_register_early - register vmap area early during boot
1906 * @vm: vm_struct to register
1907 * @align: requested alignment
1908 *
1909 * This function is used to register kernel vm area before
1910 * vmalloc_init() is called. @vm->size and @vm->flags should contain
1911 * proper values on entry and other fields should be zero. On return,
1912 * vm->addr contains the allocated address.
1913 *
1914 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1915 */
1916void __init vm_area_register_early(struct vm_struct *vm, size_t align)
1917{
1918 static size_t vm_init_off __initdata;
1919 unsigned long addr;
1920
1921 addr = ALIGN(VMALLOC_START + vm_init_off, align);
1922 vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
1923
1924 vm->addr = (void *)addr;
1925
1926 vm_area_add_early(vm);
1927}
1928
1929static void vmap_init_free_space(void)
1930{
1931 unsigned long vmap_start = 1;
1932 const unsigned long vmap_end = ULONG_MAX;
1933 struct vmap_area *busy, *free;
1934
1935 /*
1936 * B F B B B F
1937 * -|-----|.....|-----|-----|-----|.....|-
1938 * | The KVA space |
1939 * |<--------------------------------->|
1940 */
1941 list_for_each_entry(busy, &vmap_area_list, list) {
1942 if (busy->va_start - vmap_start > 0) {
1943 free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
1944 if (!WARN_ON_ONCE(!free)) {
1945 free->va_start = vmap_start;
1946 free->va_end = busy->va_start;
1947
1948 insert_vmap_area_augment(free, NULL,
1949 &free_vmap_area_root,
1950 &free_vmap_area_list);
1951 }
1952 }
1953
1954 vmap_start = busy->va_end;
1955 }
1956
1957 if (vmap_end - vmap_start > 0) {
1958 free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
1959 if (!WARN_ON_ONCE(!free)) {
1960 free->va_start = vmap_start;
1961 free->va_end = vmap_end;
1962
1963 insert_vmap_area_augment(free, NULL,
1964 &free_vmap_area_root,
1965 &free_vmap_area_list);
1966 }
1967 }
1968}
1969
1970void __init vmalloc_init(void)
1971{
1972 struct vmap_area *va;
1973 struct vm_struct *tmp;
1974 int i;
1975
1976 /*
1977 * Create the cache for vmap_area objects.
1978 */
1979 vmap_area_cachep = KMEM_CACHE(vmap_area, SLAB_PANIC);
1980
1981 for_each_possible_cpu(i) {
1982 struct vmap_block_queue *vbq;
1983 struct vfree_deferred *p;
1984
1985 vbq = &per_cpu(vmap_block_queue, i);
1986 spin_lock_init(&vbq->lock);
1987 INIT_LIST_HEAD(&vbq->free);
1988 p = &per_cpu(vfree_deferred, i);
1989 init_llist_head(&p->list);
1990 INIT_WORK(&p->wq, free_work);
1991 }
1992
1993 /* Import existing vmlist entries. */
1994 for (tmp = vmlist; tmp; tmp = tmp->next) {
1995 va = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
1996 if (WARN_ON_ONCE(!va))
1997 continue;
1998
1999 va->va_start = (unsigned long)tmp->addr;
2000 va->va_end = va->va_start + tmp->size;
2001 va->vm = tmp;
2002 insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
2003 }
2004
2005 /*
2006 * Now we can initialize a free vmap space.
2007 */
2008 vmap_init_free_space();
2009 vmap_initialized = true;
2010}
2011
2012/**
2013 * unmap_kernel_range - unmap kernel VM area and flush cache and TLB
2014 * @addr: start of the VM area to unmap
2015 * @size: size of the VM area to unmap
2016 *
2017 * Similar to unmap_kernel_range_noflush() but flushes vcache before
2018 * the unmapping and tlb after.
2019 */
2020void unmap_kernel_range(unsigned long addr, unsigned long size)
2021{
2022 unsigned long end = addr + size;
2023
2024 flush_cache_vunmap(addr, end);
2025 unmap_kernel_range_noflush(addr, size);
2026 flush_tlb_kernel_range(addr, end);
2027}
2028
2029static inline void setup_vmalloc_vm_locked(struct vm_struct *vm,
2030 struct vmap_area *va, unsigned long flags, const void *caller)
2031{
2032 vm->flags = flags;
2033 vm->addr = (void *)va->va_start;
2034 vm->size = va->va_end - va->va_start;
2035 vm->caller = caller;
2036 va->vm = vm;
2037}
2038
2039static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
2040 unsigned long flags, const void *caller)
2041{
2042 spin_lock(&vmap_area_lock);
2043 setup_vmalloc_vm_locked(vm, va, flags, caller);
2044 spin_unlock(&vmap_area_lock);
2045}
2046
2047static void clear_vm_uninitialized_flag(struct vm_struct *vm)
2048{
2049 /*
2050 * Before removing VM_UNINITIALIZED,
2051 * we should make sure that vm has proper values.
2052 * Pair with smp_rmb() in show_numa_info().
2053 */
2054 smp_wmb();
2055 vm->flags &= ~VM_UNINITIALIZED;
2056}
2057
2058static struct vm_struct *__get_vm_area_node(unsigned long size,
2059 unsigned long align, unsigned long flags, unsigned long start,
2060 unsigned long end, int node, gfp_t gfp_mask, const void *caller)
2061{
2062 struct vmap_area *va;
2063 struct vm_struct *area;
2064 unsigned long requested_size = size;
2065
2066 BUG_ON(in_interrupt());
2067 size = PAGE_ALIGN(size);
2068 if (unlikely(!size))
2069 return NULL;
2070
2071 if (flags & VM_IOREMAP)
2072 align = 1ul << clamp_t(int, get_count_order_long(size),
2073 PAGE_SHIFT, IOREMAP_MAX_ORDER);
2074
2075 area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
2076 if (unlikely(!area))
2077 return NULL;
2078
2079 if (!(flags & VM_NO_GUARD))
2080 size += PAGE_SIZE;
2081
2082 va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
2083 if (IS_ERR(va)) {
2084 kfree(area);
2085 return NULL;
2086 }
2087
2088 kasan_unpoison_vmalloc((void *)va->va_start, requested_size);
2089
2090 setup_vmalloc_vm(area, va, flags, caller);
2091
2092 return area;
2093}
2094
2095struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
2096 unsigned long start, unsigned long end,
2097 const void *caller)
2098{
2099 return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
2100 GFP_KERNEL, caller);
2101}
2102
2103/**
2104 * get_vm_area - reserve a contiguous kernel virtual area
2105 * @size: size of the area
2106 * @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC
2107 *
2108 * Search an area of @size in the kernel virtual mapping area,
2109 * and reserved it for out purposes. Returns the area descriptor
2110 * on success or %NULL on failure.
2111 *
2112 * Return: the area descriptor on success or %NULL on failure.
2113 */
2114struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
2115{
2116 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
2117 NUMA_NO_NODE, GFP_KERNEL,
2118 __builtin_return_address(0));
2119}
2120
2121struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
2122 const void *caller)
2123{
2124 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
2125 NUMA_NO_NODE, GFP_KERNEL, caller);
2126}
2127
2128/**
2129 * find_vm_area - find a continuous kernel virtual area
2130 * @addr: base address
2131 *
2132 * Search for the kernel VM area starting at @addr, and return it.
2133 * It is up to the caller to do all required locking to keep the returned
2134 * pointer valid.
2135 *
2136 * Return: pointer to the found area or %NULL on faulure
2137 */
2138struct vm_struct *find_vm_area(const void *addr)
2139{
2140 struct vmap_area *va;
2141
2142 va = find_vmap_area((unsigned long)addr);
2143 if (!va)
2144 return NULL;
2145
2146 return va->vm;
2147}
2148
2149/**
2150 * remove_vm_area - find and remove a continuous kernel virtual area
2151 * @addr: base address
2152 *
2153 * Search for the kernel VM area starting at @addr, and remove it.
2154 * This function returns the found VM area, but using it is NOT safe
2155 * on SMP machines, except for its size or flags.
2156 *
2157 * Return: pointer to the found area or %NULL on faulure
2158 */
2159struct vm_struct *remove_vm_area(const void *addr)
2160{
2161 struct vmap_area *va;
2162
2163 might_sleep();
2164
2165 spin_lock(&vmap_area_lock);
2166 va = __find_vmap_area((unsigned long)addr);
2167 if (va && va->vm) {
2168 struct vm_struct *vm = va->vm;
2169
2170 va->vm = NULL;
2171 spin_unlock(&vmap_area_lock);
2172
2173 kasan_free_shadow(vm);
2174 free_unmap_vmap_area(va);
2175
2176 return vm;
2177 }
2178
2179 spin_unlock(&vmap_area_lock);
2180 return NULL;
2181}
2182
2183static inline void set_area_direct_map(const struct vm_struct *area,
2184 int (*set_direct_map)(struct page *page))
2185{
2186 int i;
2187
2188 for (i = 0; i < area->nr_pages; i++)
2189 if (page_address(area->pages[i]))
2190 set_direct_map(area->pages[i]);
2191}
2192
2193/* Handle removing and resetting vm mappings related to the vm_struct. */
2194static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
2195{
2196 unsigned long start = ULONG_MAX, end = 0;
2197 int flush_reset = area->flags & VM_FLUSH_RESET_PERMS;
2198 int flush_dmap = 0;
2199 int i;
2200
2201 remove_vm_area(area->addr);
2202
2203 /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */
2204 if (!flush_reset)
2205 return;
2206
2207 /*
2208 * If not deallocating pages, just do the flush of the VM area and
2209 * return.
2210 */
2211 if (!deallocate_pages) {
2212 vm_unmap_aliases();
2213 return;
2214 }
2215
2216 /*
2217 * If execution gets here, flush the vm mapping and reset the direct
2218 * map. Find the start and end range of the direct mappings to make sure
2219 * the vm_unmap_aliases() flush includes the direct map.
2220 */
2221 for (i = 0; i < area->nr_pages; i++) {
2222 unsigned long addr = (unsigned long)page_address(area->pages[i]);
2223 if (addr) {
2224 start = min(addr, start);
2225 end = max(addr + PAGE_SIZE, end);
2226 flush_dmap = 1;
2227 }
2228 }
2229
2230 /*
2231 * Set direct map to something invalid so that it won't be cached if
2232 * there are any accesses after the TLB flush, then flush the TLB and
2233 * reset the direct map permissions to the default.
2234 */
2235 set_area_direct_map(area, set_direct_map_invalid_noflush);
2236 _vm_unmap_aliases(start, end, flush_dmap);
2237 set_area_direct_map(area, set_direct_map_default_noflush);
2238}
2239
2240static void __vunmap(const void *addr, int deallocate_pages)
2241{
2242 struct vm_struct *area;
2243
2244 if (!addr)
2245 return;
2246
2247 if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n",
2248 addr))
2249 return;
2250
2251 area = find_vm_area(addr);
2252 if (unlikely(!area)) {
2253 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
2254 addr);
2255 return;
2256 }
2257
2258 debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
2259 debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
2260
2261 kasan_poison_vmalloc(area->addr, area->size);
2262
2263 vm_remove_mappings(area, deallocate_pages);
2264
2265 if (deallocate_pages) {
2266 int i;
2267
2268 for (i = 0; i < area->nr_pages; i++) {
2269 struct page *page = area->pages[i];
2270
2271 BUG_ON(!page);
2272 __free_pages(page, 0);
2273 }
2274 atomic_long_sub(area->nr_pages, &nr_vmalloc_pages);
2275
2276 kvfree(area->pages);
2277 }
2278
2279 kfree(area);
2280 return;
2281}
2282
2283static inline void __vfree_deferred(const void *addr)
2284{
2285 /*
2286 * Use raw_cpu_ptr() because this can be called from preemptible
2287 * context. Preemption is absolutely fine here, because the llist_add()
2288 * implementation is lockless, so it works even if we are adding to
2289 * another cpu's list. schedule_work() should be fine with this too.
2290 */
2291 struct vfree_deferred *p = raw_cpu_ptr(&vfree_deferred);
2292
2293 if (llist_add((struct llist_node *)addr, &p->list))
2294 schedule_work(&p->wq);
2295}
2296
2297/**
2298 * vfree_atomic - release memory allocated by vmalloc()
2299 * @addr: memory base address
2300 *
2301 * This one is just like vfree() but can be called in any atomic context
2302 * except NMIs.
2303 */
2304void vfree_atomic(const void *addr)
2305{
2306 BUG_ON(in_nmi());
2307
2308 kmemleak_free(addr);
2309
2310 if (!addr)
2311 return;
2312 __vfree_deferred(addr);
2313}
2314
2315static void __vfree(const void *addr)
2316{
2317 if (unlikely(in_interrupt()))
2318 __vfree_deferred(addr);
2319 else
2320 __vunmap(addr, 1);
2321}
2322
2323/**
2324 * vfree - release memory allocated by vmalloc()
2325 * @addr: memory base address
2326 *
2327 * Free the virtually continuous memory area starting at @addr, as
2328 * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
2329 * NULL, no operation is performed.
2330 *
2331 * Must not be called in NMI context (strictly speaking, only if we don't
2332 * have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling
2333 * conventions for vfree() arch-depenedent would be a really bad idea)
2334 *
2335 * May sleep if called *not* from interrupt context.
2336 *
2337 * NOTE: assumes that the object at @addr has a size >= sizeof(llist_node)
2338 */
2339void vfree(const void *addr)
2340{
2341 BUG_ON(in_nmi());
2342
2343 kmemleak_free(addr);
2344
2345 might_sleep_if(!in_interrupt());
2346
2347 if (!addr)
2348 return;
2349
2350 __vfree(addr);
2351}
2352EXPORT_SYMBOL(vfree);
2353
2354/**
2355 * vunmap - release virtual mapping obtained by vmap()
2356 * @addr: memory base address
2357 *
2358 * Free the virtually contiguous memory area starting at @addr,
2359 * which was created from the page array passed to vmap().
2360 *
2361 * Must not be called in interrupt context.
2362 */
2363void vunmap(const void *addr)
2364{
2365 BUG_ON(in_interrupt());
2366 might_sleep();
2367 if (addr)
2368 __vunmap(addr, 0);
2369}
2370EXPORT_SYMBOL(vunmap);
2371
2372/**
2373 * vmap - map an array of pages into virtually contiguous space
2374 * @pages: array of page pointers
2375 * @count: number of pages to map
2376 * @flags: vm_area->flags
2377 * @prot: page protection for the mapping
2378 *
2379 * Maps @count pages from @pages into contiguous kernel virtual
2380 * space.
2381 *
2382 * Return: the address of the area or %NULL on failure
2383 */
2384void *vmap(struct page **pages, unsigned int count,
2385 unsigned long flags, pgprot_t prot)
2386{
2387 struct vm_struct *area;
2388 unsigned long size; /* In bytes */
2389
2390 might_sleep();
2391
2392 if (count > totalram_pages())
2393 return NULL;
2394
2395 size = (unsigned long)count << PAGE_SHIFT;
2396 area = get_vm_area_caller(size, flags, __builtin_return_address(0));
2397 if (!area)
2398 return NULL;
2399
2400 if (map_kernel_range((unsigned long)area->addr, size, pgprot_nx(prot),
2401 pages) < 0) {
2402 vunmap(area->addr);
2403 return NULL;
2404 }
2405
2406 return area->addr;
2407}
2408EXPORT_SYMBOL(vmap);
2409
2410static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
2411 pgprot_t prot, int node)
2412{
2413 struct page **pages;
2414 unsigned int nr_pages, array_size, i;
2415 const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
2416 const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
2417 const gfp_t highmem_mask = (gfp_mask & (GFP_DMA | GFP_DMA32)) ?
2418 0 :
2419 __GFP_HIGHMEM;
2420
2421 nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
2422 array_size = (nr_pages * sizeof(struct page *));
2423
2424 /* Please note that the recursion is strictly bounded. */
2425 if (array_size > PAGE_SIZE) {
2426 pages = __vmalloc_node(array_size, 1, nested_gfp|highmem_mask,
2427 node, area->caller);
2428 } else {
2429 pages = kmalloc_node(array_size, nested_gfp, node);
2430 }
2431
2432 if (!pages) {
2433 remove_vm_area(area->addr);
2434 kfree(area);
2435 return NULL;
2436 }
2437
2438 area->pages = pages;
2439 area->nr_pages = nr_pages;
2440
2441 for (i = 0; i < area->nr_pages; i++) {
2442 struct page *page;
2443
2444 if (node == NUMA_NO_NODE)
2445 page = alloc_page(alloc_mask|highmem_mask);
2446 else
2447 page = alloc_pages_node(node, alloc_mask|highmem_mask, 0);
2448
2449 if (unlikely(!page)) {
2450 /* Successfully allocated i pages, free them in __vunmap() */
2451 area->nr_pages = i;
2452 atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
2453 goto fail;
2454 }
2455 area->pages[i] = page;
2456 if (gfpflags_allow_blocking(gfp_mask))
2457 cond_resched();
2458 }
2459 atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
2460
2461 if (map_kernel_range((unsigned long)area->addr, get_vm_area_size(area),
2462 prot, pages) < 0)
2463 goto fail;
2464
2465 return area->addr;
2466
2467fail:
2468 warn_alloc(gfp_mask, NULL,
2469 "vmalloc: allocation failure, allocated %ld of %ld bytes",
2470 (area->nr_pages*PAGE_SIZE), area->size);
2471 __vfree(area->addr);
2472 return NULL;
2473}
2474
2475/**
2476 * __vmalloc_node_range - allocate virtually contiguous memory
2477 * @size: allocation size
2478 * @align: desired alignment
2479 * @start: vm area range start
2480 * @end: vm area range end
2481 * @gfp_mask: flags for the page level allocator
2482 * @prot: protection mask for the allocated pages
2483 * @vm_flags: additional vm area flags (e.g. %VM_NO_GUARD)
2484 * @node: node to use for allocation or NUMA_NO_NODE
2485 * @caller: caller's return address
2486 *
2487 * Allocate enough pages to cover @size from the page level
2488 * allocator with @gfp_mask flags. Map them into contiguous
2489 * kernel virtual space, using a pagetable protection of @prot.
2490 *
2491 * Return: the address of the area or %NULL on failure
2492 */
2493void *__vmalloc_node_range(unsigned long size, unsigned long align,
2494 unsigned long start, unsigned long end, gfp_t gfp_mask,
2495 pgprot_t prot, unsigned long vm_flags, int node,
2496 const void *caller)
2497{
2498 struct vm_struct *area;
2499 void *addr;
2500 unsigned long real_size = size;
2501
2502 size = PAGE_ALIGN(size);
2503 if (!size || (size >> PAGE_SHIFT) > totalram_pages())
2504 goto fail;
2505
2506 area = __get_vm_area_node(real_size, align, VM_ALLOC | VM_UNINITIALIZED |
2507 vm_flags, start, end, node, gfp_mask, caller);
2508 if (!area)
2509 goto fail;
2510
2511 addr = __vmalloc_area_node(area, gfp_mask, prot, node);
2512 if (!addr)
2513 return NULL;
2514
2515 /*
2516 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
2517 * flag. It means that vm_struct is not fully initialized.
2518 * Now, it is fully initialized, so remove this flag here.
2519 */
2520 clear_vm_uninitialized_flag(area);
2521
2522 kmemleak_vmalloc(area, size, gfp_mask);
2523
2524 return addr;
2525
2526fail:
2527 warn_alloc(gfp_mask, NULL,
2528 "vmalloc: allocation failure: %lu bytes", real_size);
2529 return NULL;
2530}
2531
2532/**
2533 * __vmalloc_node - allocate virtually contiguous memory
2534 * @size: allocation size
2535 * @align: desired alignment
2536 * @gfp_mask: flags for the page level allocator
2537 * @node: node to use for allocation or NUMA_NO_NODE
2538 * @caller: caller's return address
2539 *
2540 * Allocate enough pages to cover @size from the page level allocator with
2541 * @gfp_mask flags. Map them into contiguous kernel virtual space.
2542 *
2543 * Reclaim modifiers in @gfp_mask - __GFP_NORETRY, __GFP_RETRY_MAYFAIL
2544 * and __GFP_NOFAIL are not supported
2545 *
2546 * Any use of gfp flags outside of GFP_KERNEL should be consulted
2547 * with mm people.
2548 *
2549 * Return: pointer to the allocated memory or %NULL on error
2550 */
2551void *__vmalloc_node(unsigned long size, unsigned long align,
2552 gfp_t gfp_mask, int node, const void *caller)
2553{
2554 return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
2555 gfp_mask, PAGE_KERNEL, 0, node, caller);
2556}
2557/*
2558 * This is only for performance analysis of vmalloc and stress purpose.
2559 * It is required by vmalloc test module, therefore do not use it other
2560 * than that.
2561 */
2562#ifdef CONFIG_TEST_VMALLOC_MODULE
2563EXPORT_SYMBOL_GPL(__vmalloc_node);
2564#endif
2565
2566void *__vmalloc(unsigned long size, gfp_t gfp_mask)
2567{
2568 return __vmalloc_node(size, 1, gfp_mask, NUMA_NO_NODE,
2569 __builtin_return_address(0));
2570}
2571EXPORT_SYMBOL(__vmalloc);
2572
2573/**
2574 * vmalloc - allocate virtually contiguous memory
2575 * @size: allocation size
2576 *
2577 * Allocate enough pages to cover @size from the page level
2578 * allocator and map them into contiguous kernel virtual space.
2579 *
2580 * For tight control over page level allocator and protection flags
2581 * use __vmalloc() instead.
2582 *
2583 * Return: pointer to the allocated memory or %NULL on error
2584 */
2585void *vmalloc(unsigned long size)
2586{
2587 return __vmalloc_node(size, 1, GFP_KERNEL, NUMA_NO_NODE,
2588 __builtin_return_address(0));
2589}
2590EXPORT_SYMBOL(vmalloc);
2591
2592/**
2593 * vzalloc - allocate virtually contiguous memory with zero fill
2594 * @size: allocation size
2595 *
2596 * Allocate enough pages to cover @size from the page level
2597 * allocator and map them into contiguous kernel virtual space.
2598 * The memory allocated is set to zero.
2599 *
2600 * For tight control over page level allocator and protection flags
2601 * use __vmalloc() instead.
2602 *
2603 * Return: pointer to the allocated memory or %NULL on error
2604 */
2605void *vzalloc(unsigned long size)
2606{
2607 return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_ZERO, NUMA_NO_NODE,
2608 __builtin_return_address(0));
2609}
2610EXPORT_SYMBOL(vzalloc);
2611
2612/**
2613 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
2614 * @size: allocation size
2615 *
2616 * The resulting memory area is zeroed so it can be mapped to userspace
2617 * without leaking data.
2618 *
2619 * Return: pointer to the allocated memory or %NULL on error
2620 */
2621void *vmalloc_user(unsigned long size)
2622{
2623 return __vmalloc_node_range(size, SHMLBA, VMALLOC_START, VMALLOC_END,
2624 GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL,
2625 VM_USERMAP, NUMA_NO_NODE,
2626 __builtin_return_address(0));
2627}
2628EXPORT_SYMBOL(vmalloc_user);
2629
2630/**
2631 * vmalloc_node - allocate memory on a specific node
2632 * @size: allocation size
2633 * @node: numa node
2634 *
2635 * Allocate enough pages to cover @size from the page level
2636 * allocator and map them into contiguous kernel virtual space.
2637 *
2638 * For tight control over page level allocator and protection flags
2639 * use __vmalloc() instead.
2640 *
2641 * Return: pointer to the allocated memory or %NULL on error
2642 */
2643void *vmalloc_node(unsigned long size, int node)
2644{
2645 return __vmalloc_node(size, 1, GFP_KERNEL, node,
2646 __builtin_return_address(0));
2647}
2648EXPORT_SYMBOL(vmalloc_node);
2649
2650/**
2651 * vzalloc_node - allocate memory on a specific node with zero fill
2652 * @size: allocation size
2653 * @node: numa node
2654 *
2655 * Allocate enough pages to cover @size from the page level
2656 * allocator and map them into contiguous kernel virtual space.
2657 * The memory allocated is set to zero.
2658 *
2659 * Return: pointer to the allocated memory or %NULL on error
2660 */
2661void *vzalloc_node(unsigned long size, int node)
2662{
2663 return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_ZERO, node,
2664 __builtin_return_address(0));
2665}
2666EXPORT_SYMBOL(vzalloc_node);
2667
2668#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
2669#define GFP_VMALLOC32 (GFP_DMA32 | GFP_KERNEL)
2670#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
2671#define GFP_VMALLOC32 (GFP_DMA | GFP_KERNEL)
2672#else
2673/*
2674 * 64b systems should always have either DMA or DMA32 zones. For others
2675 * GFP_DMA32 should do the right thing and use the normal zone.
2676 */
2677#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
2678#endif
2679
2680/**
2681 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
2682 * @size: allocation size
2683 *
2684 * Allocate enough 32bit PA addressable pages to cover @size from the
2685 * page level allocator and map them into contiguous kernel virtual space.
2686 *
2687 * Return: pointer to the allocated memory or %NULL on error
2688 */
2689void *vmalloc_32(unsigned long size)
2690{
2691 return __vmalloc_node(size, 1, GFP_VMALLOC32, NUMA_NO_NODE,
2692 __builtin_return_address(0));
2693}
2694EXPORT_SYMBOL(vmalloc_32);
2695
2696/**
2697 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
2698 * @size: allocation size
2699 *
2700 * The resulting memory area is 32bit addressable and zeroed so it can be
2701 * mapped to userspace without leaking data.
2702 *
2703 * Return: pointer to the allocated memory or %NULL on error
2704 */
2705void *vmalloc_32_user(unsigned long size)
2706{
2707 return __vmalloc_node_range(size, SHMLBA, VMALLOC_START, VMALLOC_END,
2708 GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
2709 VM_USERMAP, NUMA_NO_NODE,
2710 __builtin_return_address(0));
2711}
2712EXPORT_SYMBOL(vmalloc_32_user);
2713
2714/*
2715 * small helper routine , copy contents to buf from addr.
2716 * If the page is not present, fill zero.
2717 */
2718
2719static int aligned_vread(char *buf, char *addr, unsigned long count)
2720{
2721 struct page *p;
2722 int copied = 0;
2723
2724 while (count) {
2725 unsigned long offset, length;
2726
2727 offset = offset_in_page(addr);
2728 length = PAGE_SIZE - offset;
2729 if (length > count)
2730 length = count;
2731 p = vmalloc_to_page(addr);
2732 /*
2733 * To do safe access to this _mapped_ area, we need
2734 * lock. But adding lock here means that we need to add
2735 * overhead of vmalloc()/vfree() calles for this _debug_
2736 * interface, rarely used. Instead of that, we'll use
2737 * kmap() and get small overhead in this access function.
2738 */
2739 if (p) {
2740 /*
2741 * we can expect USER0 is not used (see vread/vwrite's
2742 * function description)
2743 */
2744 void *map = kmap_atomic(p);
2745 memcpy(buf, map + offset, length);
2746 kunmap_atomic(map);
2747 } else
2748 memset(buf, 0, length);
2749
2750 addr += length;
2751 buf += length;
2752 copied += length;
2753 count -= length;
2754 }
2755 return copied;
2756}
2757
2758static int aligned_vwrite(char *buf, char *addr, unsigned long count)
2759{
2760 struct page *p;
2761 int copied = 0;
2762
2763 while (count) {
2764 unsigned long offset, length;
2765
2766 offset = offset_in_page(addr);
2767 length = PAGE_SIZE - offset;
2768 if (length > count)
2769 length = count;
2770 p = vmalloc_to_page(addr);
2771 /*
2772 * To do safe access to this _mapped_ area, we need
2773 * lock. But adding lock here means that we need to add
2774 * overhead of vmalloc()/vfree() calles for this _debug_
2775 * interface, rarely used. Instead of that, we'll use
2776 * kmap() and get small overhead in this access function.
2777 */
2778 if (p) {
2779 /*
2780 * we can expect USER0 is not used (see vread/vwrite's
2781 * function description)
2782 */
2783 void *map = kmap_atomic(p);
2784 memcpy(map + offset, buf, length);
2785 kunmap_atomic(map);
2786 }
2787 addr += length;
2788 buf += length;
2789 copied += length;
2790 count -= length;
2791 }
2792 return copied;
2793}
2794
2795/**
2796 * vread() - read vmalloc area in a safe way.
2797 * @buf: buffer for reading data
2798 * @addr: vm address.
2799 * @count: number of bytes to be read.
2800 *
2801 * This function checks that addr is a valid vmalloc'ed area, and
2802 * copy data from that area to a given buffer. If the given memory range
2803 * of [addr...addr+count) includes some valid address, data is copied to
2804 * proper area of @buf. If there are memory holes, they'll be zero-filled.
2805 * IOREMAP area is treated as memory hole and no copy is done.
2806 *
2807 * If [addr...addr+count) doesn't includes any intersects with alive
2808 * vm_struct area, returns 0. @buf should be kernel's buffer.
2809 *
2810 * Note: In usual ops, vread() is never necessary because the caller
2811 * should know vmalloc() area is valid and can use memcpy().
2812 * This is for routines which have to access vmalloc area without
2813 * any information, as /dev/kmem.
2814 *
2815 * Return: number of bytes for which addr and buf should be increased
2816 * (same number as @count) or %0 if [addr...addr+count) doesn't
2817 * include any intersection with valid vmalloc area
2818 */
2819long vread(char *buf, char *addr, unsigned long count)
2820{
2821 struct vmap_area *va;
2822 struct vm_struct *vm;
2823 char *vaddr, *buf_start = buf;
2824 unsigned long buflen = count;
2825 unsigned long n;
2826
2827 /* Don't allow overflow */
2828 if ((unsigned long) addr + count < count)
2829 count = -(unsigned long) addr;
2830
2831 spin_lock(&vmap_area_lock);
2832 list_for_each_entry(va, &vmap_area_list, list) {
2833 if (!count)
2834 break;
2835
2836 if (!va->vm)
2837 continue;
2838
2839 vm = va->vm;
2840 vaddr = (char *) vm->addr;
2841 if (addr >= vaddr + get_vm_area_size(vm))
2842 continue;
2843 while (addr < vaddr) {
2844 if (count == 0)
2845 goto finished;
2846 *buf = '\0';
2847 buf++;
2848 addr++;
2849 count--;
2850 }
2851 n = vaddr + get_vm_area_size(vm) - addr;
2852 if (n > count)
2853 n = count;
2854 if (!(vm->flags & VM_IOREMAP))
2855 aligned_vread(buf, addr, n);
2856 else /* IOREMAP area is treated as memory hole */
2857 memset(buf, 0, n);
2858 buf += n;
2859 addr += n;
2860 count -= n;
2861 }
2862finished:
2863 spin_unlock(&vmap_area_lock);
2864
2865 if (buf == buf_start)
2866 return 0;
2867 /* zero-fill memory holes */
2868 if (buf != buf_start + buflen)
2869 memset(buf, 0, buflen - (buf - buf_start));
2870
2871 return buflen;
2872}
2873
2874/**
2875 * vwrite() - write vmalloc area in a safe way.
2876 * @buf: buffer for source data
2877 * @addr: vm address.
2878 * @count: number of bytes to be read.
2879 *
2880 * This function checks that addr is a valid vmalloc'ed area, and
2881 * copy data from a buffer to the given addr. If specified range of
2882 * [addr...addr+count) includes some valid address, data is copied from
2883 * proper area of @buf. If there are memory holes, no copy to hole.
2884 * IOREMAP area is treated as memory hole and no copy is done.
2885 *
2886 * If [addr...addr+count) doesn't includes any intersects with alive
2887 * vm_struct area, returns 0. @buf should be kernel's buffer.
2888 *
2889 * Note: In usual ops, vwrite() is never necessary because the caller
2890 * should know vmalloc() area is valid and can use memcpy().
2891 * This is for routines which have to access vmalloc area without
2892 * any information, as /dev/kmem.
2893 *
2894 * Return: number of bytes for which addr and buf should be
2895 * increased (same number as @count) or %0 if [addr...addr+count)
2896 * doesn't include any intersection with valid vmalloc area
2897 */
2898long vwrite(char *buf, char *addr, unsigned long count)
2899{
2900 struct vmap_area *va;
2901 struct vm_struct *vm;
2902 char *vaddr;
2903 unsigned long n, buflen;
2904 int copied = 0;
2905
2906 /* Don't allow overflow */
2907 if ((unsigned long) addr + count < count)
2908 count = -(unsigned long) addr;
2909 buflen = count;
2910
2911 spin_lock(&vmap_area_lock);
2912 list_for_each_entry(va, &vmap_area_list, list) {
2913 if (!count)
2914 break;
2915
2916 if (!va->vm)
2917 continue;
2918
2919 vm = va->vm;
2920 vaddr = (char *) vm->addr;
2921 if (addr >= vaddr + get_vm_area_size(vm))
2922 continue;
2923 while (addr < vaddr) {
2924 if (count == 0)
2925 goto finished;
2926 buf++;
2927 addr++;
2928 count--;
2929 }
2930 n = vaddr + get_vm_area_size(vm) - addr;
2931 if (n > count)
2932 n = count;
2933 if (!(vm->flags & VM_IOREMAP)) {
2934 aligned_vwrite(buf, addr, n);
2935 copied++;
2936 }
2937 buf += n;
2938 addr += n;
2939 count -= n;
2940 }
2941finished:
2942 spin_unlock(&vmap_area_lock);
2943 if (!copied)
2944 return 0;
2945 return buflen;
2946}
2947
2948/**
2949 * remap_vmalloc_range_partial - map vmalloc pages to userspace
2950 * @vma: vma to cover
2951 * @uaddr: target user address to start at
2952 * @kaddr: virtual address of vmalloc kernel memory
2953 * @pgoff: offset from @kaddr to start at
2954 * @size: size of map area
2955 *
2956 * Returns: 0 for success, -Exxx on failure
2957 *
2958 * This function checks that @kaddr is a valid vmalloc'ed area,
2959 * and that it is big enough to cover the range starting at
2960 * @uaddr in @vma. Will return failure if that criteria isn't
2961 * met.
2962 *
2963 * Similar to remap_pfn_range() (see mm/memory.c)
2964 */
2965int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
2966 void *kaddr, unsigned long pgoff,
2967 unsigned long size)
2968{
2969 struct vm_struct *area;
2970 unsigned long off;
2971 unsigned long end_index;
2972
2973 if (check_shl_overflow(pgoff, PAGE_SHIFT, &off))
2974 return -EINVAL;
2975
2976 size = PAGE_ALIGN(size);
2977
2978 if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr))
2979 return -EINVAL;
2980
2981 area = find_vm_area(kaddr);
2982 if (!area)
2983 return -EINVAL;
2984
2985 if (!(area->flags & (VM_USERMAP | VM_DMA_COHERENT)))
2986 return -EINVAL;
2987
2988 if (check_add_overflow(size, off, &end_index) ||
2989 end_index > get_vm_area_size(area))
2990 return -EINVAL;
2991 kaddr += off;
2992
2993 do {
2994 struct page *page = vmalloc_to_page(kaddr);
2995 int ret;
2996
2997 ret = vm_insert_page(vma, uaddr, page);
2998 if (ret)
2999 return ret;
3000
3001 uaddr += PAGE_SIZE;
3002 kaddr += PAGE_SIZE;
3003 size -= PAGE_SIZE;
3004 } while (size > 0);
3005
3006 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
3007
3008 return 0;
3009}
3010EXPORT_SYMBOL(remap_vmalloc_range_partial);
3011
3012/**
3013 * remap_vmalloc_range - map vmalloc pages to userspace
3014 * @vma: vma to cover (map full range of vma)
3015 * @addr: vmalloc memory
3016 * @pgoff: number of pages into addr before first page to map
3017 *
3018 * Returns: 0 for success, -Exxx on failure
3019 *
3020 * This function checks that addr is a valid vmalloc'ed area, and
3021 * that it is big enough to cover the vma. Will return failure if
3022 * that criteria isn't met.
3023 *
3024 * Similar to remap_pfn_range() (see mm/memory.c)
3025 */
3026int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
3027 unsigned long pgoff)
3028{
3029 return remap_vmalloc_range_partial(vma, vma->vm_start,
3030 addr, pgoff,
3031 vma->vm_end - vma->vm_start);
3032}
3033EXPORT_SYMBOL(remap_vmalloc_range);
3034
3035static int f(pte_t *pte, unsigned long addr, void *data)
3036{
3037 pte_t ***p = data;
3038
3039 if (p) {
3040 *(*p) = pte;
3041 (*p)++;
3042 }
3043 return 0;
3044}
3045
3046/**
3047 * alloc_vm_area - allocate a range of kernel address space
3048 * @size: size of the area
3049 * @ptes: returns the PTEs for the address space
3050 *
3051 * Returns: NULL on failure, vm_struct on success
3052 *
3053 * This function reserves a range of kernel address space, and
3054 * allocates pagetables to map that range. No actual mappings
3055 * are created.
3056 *
3057 * If @ptes is non-NULL, pointers to the PTEs (in init_mm)
3058 * allocated for the VM area are returned.
3059 */
3060struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
3061{
3062 struct vm_struct *area;
3063
3064 area = get_vm_area_caller(size, VM_IOREMAP,
3065 __builtin_return_address(0));
3066 if (area == NULL)
3067 return NULL;
3068
3069 /*
3070 * This ensures that page tables are constructed for this region
3071 * of kernel virtual address space and mapped into init_mm.
3072 */
3073 if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
3074 size, f, ptes ? &ptes : NULL)) {
3075 free_vm_area(area);
3076 return NULL;
3077 }
3078
3079 return area;
3080}
3081EXPORT_SYMBOL_GPL(alloc_vm_area);
3082
3083void free_vm_area(struct vm_struct *area)
3084{
3085 struct vm_struct *ret;
3086 ret = remove_vm_area(area->addr);
3087 BUG_ON(ret != area);
3088 kfree(area);
3089}
3090EXPORT_SYMBOL_GPL(free_vm_area);
3091
3092#ifdef CONFIG_SMP
3093static struct vmap_area *node_to_va(struct rb_node *n)
3094{
3095 return rb_entry_safe(n, struct vmap_area, rb_node);
3096}
3097
3098/**
3099 * pvm_find_va_enclose_addr - find the vmap_area @addr belongs to
3100 * @addr: target address
3101 *
3102 * Returns: vmap_area if it is found. If there is no such area
3103 * the first highest(reverse order) vmap_area is returned
3104 * i.e. va->va_start < addr && va->va_end < addr or NULL
3105 * if there are no any areas before @addr.
3106 */
3107static struct vmap_area *
3108pvm_find_va_enclose_addr(unsigned long addr)
3109{
3110 struct vmap_area *va, *tmp;
3111 struct rb_node *n;
3112
3113 n = free_vmap_area_root.rb_node;
3114 va = NULL;
3115
3116 while (n) {
3117 tmp = rb_entry(n, struct vmap_area, rb_node);
3118 if (tmp->va_start <= addr) {
3119 va = tmp;
3120 if (tmp->va_end >= addr)
3121 break;
3122
3123 n = n->rb_right;
3124 } else {
3125 n = n->rb_left;
3126 }
3127 }
3128
3129 return va;
3130}
3131
3132/**
3133 * pvm_determine_end_from_reverse - find the highest aligned address
3134 * of free block below VMALLOC_END
3135 * @va:
3136 * in - the VA we start the search(reverse order);
3137 * out - the VA with the highest aligned end address.
3138 *
3139 * Returns: determined end address within vmap_area
3140 */
3141static unsigned long
3142pvm_determine_end_from_reverse(struct vmap_area **va, unsigned long align)
3143{
3144 unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
3145 unsigned long addr;
3146
3147 if (likely(*va)) {
3148 list_for_each_entry_from_reverse((*va),
3149 &free_vmap_area_list, list) {
3150 addr = min((*va)->va_end & ~(align - 1), vmalloc_end);
3151 if ((*va)->va_start < addr)
3152 return addr;
3153 }
3154 }
3155
3156 return 0;
3157}
3158
3159/**
3160 * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
3161 * @offsets: array containing offset of each area
3162 * @sizes: array containing size of each area
3163 * @nr_vms: the number of areas to allocate
3164 * @align: alignment, all entries in @offsets and @sizes must be aligned to this
3165 *
3166 * Returns: kmalloc'd vm_struct pointer array pointing to allocated
3167 * vm_structs on success, %NULL on failure
3168 *
3169 * Percpu allocator wants to use congruent vm areas so that it can
3170 * maintain the offsets among percpu areas. This function allocates
3171 * congruent vmalloc areas for it with GFP_KERNEL. These areas tend to
3172 * be scattered pretty far, distance between two areas easily going up
3173 * to gigabytes. To avoid interacting with regular vmallocs, these
3174 * areas are allocated from top.
3175 *
3176 * Despite its complicated look, this allocator is rather simple. It
3177 * does everything top-down and scans free blocks from the end looking
3178 * for matching base. While scanning, if any of the areas do not fit the
3179 * base address is pulled down to fit the area. Scanning is repeated till
3180 * all the areas fit and then all necessary data structures are inserted
3181 * and the result is returned.
3182 */
3183struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
3184 const size_t *sizes, int nr_vms,
3185 size_t align)
3186{
3187 const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
3188 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
3189 struct vmap_area **vas, *va;
3190 struct vm_struct **vms;
3191 int area, area2, last_area, term_area;
3192 unsigned long base, start, size, end, last_end, orig_start, orig_end;
3193 bool purged = false;
3194 enum fit_type type;
3195
3196 /* verify parameters and allocate data structures */
3197 BUG_ON(offset_in_page(align) || !is_power_of_2(align));
3198 for (last_area = 0, area = 0; area < nr_vms; area++) {
3199 start = offsets[area];
3200 end = start + sizes[area];
3201
3202 /* is everything aligned properly? */
3203 BUG_ON(!IS_ALIGNED(offsets[area], align));
3204 BUG_ON(!IS_ALIGNED(sizes[area], align));
3205
3206 /* detect the area with the highest address */
3207 if (start > offsets[last_area])
3208 last_area = area;
3209
3210 for (area2 = area + 1; area2 < nr_vms; area2++) {
3211 unsigned long start2 = offsets[area2];
3212 unsigned long end2 = start2 + sizes[area2];
3213
3214 BUG_ON(start2 < end && start < end2);
3215 }
3216 }
3217 last_end = offsets[last_area] + sizes[last_area];
3218
3219 if (vmalloc_end - vmalloc_start < last_end) {
3220 WARN_ON(true);
3221 return NULL;
3222 }
3223
3224 vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL);
3225 vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL);
3226 if (!vas || !vms)
3227 goto err_free2;
3228
3229 for (area = 0; area < nr_vms; area++) {
3230 vas[area] = kmem_cache_zalloc(vmap_area_cachep, GFP_KERNEL);
3231 vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL);
3232 if (!vas[area] || !vms[area])
3233 goto err_free;
3234 }
3235retry:
3236 spin_lock(&free_vmap_area_lock);
3237
3238 /* start scanning - we scan from the top, begin with the last area */
3239 area = term_area = last_area;
3240 start = offsets[area];
3241 end = start + sizes[area];
3242
3243 va = pvm_find_va_enclose_addr(vmalloc_end);
3244 base = pvm_determine_end_from_reverse(&va, align) - end;
3245
3246 while (true) {
3247 /*
3248 * base might have underflowed, add last_end before
3249 * comparing.
3250 */
3251 if (base + last_end < vmalloc_start + last_end)
3252 goto overflow;
3253
3254 /*
3255 * Fitting base has not been found.
3256 */
3257 if (va == NULL)
3258 goto overflow;
3259
3260 /*
3261 * If required width exceeds current VA block, move
3262 * base downwards and then recheck.
3263 */
3264 if (base + end > va->va_end) {
3265 base = pvm_determine_end_from_reverse(&va, align) - end;
3266 term_area = area;
3267 continue;
3268 }
3269
3270 /*
3271 * If this VA does not fit, move base downwards and recheck.
3272 */
3273 if (base + start < va->va_start) {
3274 va = node_to_va(rb_prev(&va->rb_node));
3275 base = pvm_determine_end_from_reverse(&va, align) - end;
3276 term_area = area;
3277 continue;
3278 }
3279
3280 /*
3281 * This area fits, move on to the previous one. If
3282 * the previous one is the terminal one, we're done.
3283 */
3284 area = (area + nr_vms - 1) % nr_vms;
3285 if (area == term_area)
3286 break;
3287
3288 start = offsets[area];
3289 end = start + sizes[area];
3290 va = pvm_find_va_enclose_addr(base + end);
3291 }
3292
3293 /* we've found a fitting base, insert all va's */
3294 for (area = 0; area < nr_vms; area++) {
3295 int ret;
3296
3297 start = base + offsets[area];
3298 size = sizes[area];
3299
3300 va = pvm_find_va_enclose_addr(start);
3301 if (WARN_ON_ONCE(va == NULL))
3302 /* It is a BUG(), but trigger recovery instead. */
3303 goto recovery;
3304
3305 type = classify_va_fit_type(va, start, size);
3306 if (WARN_ON_ONCE(type == NOTHING_FIT))
3307 /* It is a BUG(), but trigger recovery instead. */
3308 goto recovery;
3309
3310 ret = adjust_va_to_fit_type(va, start, size, type);
3311 if (unlikely(ret))
3312 goto recovery;
3313
3314 /* Allocated area. */
3315 va = vas[area];
3316 va->va_start = start;
3317 va->va_end = start + size;
3318 }
3319
3320 spin_unlock(&free_vmap_area_lock);
3321
3322 /* populate the kasan shadow space */
3323 for (area = 0; area < nr_vms; area++) {
3324 if (kasan_populate_vmalloc(vas[area]->va_start, sizes[area]))
3325 goto err_free_shadow;
3326
3327 kasan_unpoison_vmalloc((void *)vas[area]->va_start,
3328 sizes[area]);
3329 }
3330
3331 /* insert all vm's */
3332 spin_lock(&vmap_area_lock);
3333 for (area = 0; area < nr_vms; area++) {
3334 insert_vmap_area(vas[area], &vmap_area_root, &vmap_area_list);
3335
3336 setup_vmalloc_vm_locked(vms[area], vas[area], VM_ALLOC,
3337 pcpu_get_vm_areas);
3338 }
3339 spin_unlock(&vmap_area_lock);
3340
3341 kfree(vas);
3342 return vms;
3343
3344recovery:
3345 /*
3346 * Remove previously allocated areas. There is no
3347 * need in removing these areas from the busy tree,
3348 * because they are inserted only on the final step
3349 * and when pcpu_get_vm_areas() is success.
3350 */
3351 while (area--) {
3352 orig_start = vas[area]->va_start;
3353 orig_end = vas[area]->va_end;
3354 va = merge_or_add_vmap_area(vas[area], &free_vmap_area_root,
3355 &free_vmap_area_list);
3356 if (va)
3357 kasan_release_vmalloc(orig_start, orig_end,
3358 va->va_start, va->va_end);
3359 vas[area] = NULL;
3360 }
3361
3362overflow:
3363 spin_unlock(&free_vmap_area_lock);
3364 if (!purged) {
3365 purge_vmap_area_lazy();
3366 purged = true;
3367
3368 /* Before "retry", check if we recover. */
3369 for (area = 0; area < nr_vms; area++) {
3370 if (vas[area])
3371 continue;
3372
3373 vas[area] = kmem_cache_zalloc(
3374 vmap_area_cachep, GFP_KERNEL);
3375 if (!vas[area])
3376 goto err_free;
3377 }
3378
3379 goto retry;
3380 }
3381
3382err_free:
3383 for (area = 0; area < nr_vms; area++) {
3384 if (vas[area])
3385 kmem_cache_free(vmap_area_cachep, vas[area]);
3386
3387 kfree(vms[area]);
3388 }
3389err_free2:
3390 kfree(vas);
3391 kfree(vms);
3392 return NULL;
3393
3394err_free_shadow:
3395 spin_lock(&free_vmap_area_lock);
3396 /*
3397 * We release all the vmalloc shadows, even the ones for regions that
3398 * hadn't been successfully added. This relies on kasan_release_vmalloc
3399 * being able to tolerate this case.
3400 */
3401 for (area = 0; area < nr_vms; area++) {
3402 orig_start = vas[area]->va_start;
3403 orig_end = vas[area]->va_end;
3404 va = merge_or_add_vmap_area(vas[area], &free_vmap_area_root,
3405 &free_vmap_area_list);
3406 if (va)
3407 kasan_release_vmalloc(orig_start, orig_end,
3408 va->va_start, va->va_end);
3409 vas[area] = NULL;
3410 kfree(vms[area]);
3411 }
3412 spin_unlock(&free_vmap_area_lock);
3413 kfree(vas);
3414 kfree(vms);
3415 return NULL;
3416}
3417
3418/**
3419 * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
3420 * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
3421 * @nr_vms: the number of allocated areas
3422 *
3423 * Free vm_structs and the array allocated by pcpu_get_vm_areas().
3424 */
3425void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
3426{
3427 int i;
3428
3429 for (i = 0; i < nr_vms; i++)
3430 free_vm_area(vms[i]);
3431 kfree(vms);
3432}
3433#endif /* CONFIG_SMP */
3434
3435#ifdef CONFIG_PROC_FS
3436static void *s_start(struct seq_file *m, loff_t *pos)
3437 __acquires(&vmap_purge_lock)
3438 __acquires(&vmap_area_lock)
3439{
3440 mutex_lock(&vmap_purge_lock);
3441 spin_lock(&vmap_area_lock);
3442
3443 return seq_list_start(&vmap_area_list, *pos);
3444}
3445
3446static void *s_next(struct seq_file *m, void *p, loff_t *pos)
3447{
3448 return seq_list_next(p, &vmap_area_list, pos);
3449}
3450
3451static void s_stop(struct seq_file *m, void *p)
3452 __releases(&vmap_purge_lock)
3453 __releases(&vmap_area_lock)
3454{
3455 mutex_unlock(&vmap_purge_lock);
3456 spin_unlock(&vmap_area_lock);
3457}
3458
3459static void show_numa_info(struct seq_file *m, struct vm_struct *v)
3460{
3461 if (IS_ENABLED(CONFIG_NUMA)) {
3462 unsigned int nr, *counters = m->private;
3463
3464 if (!counters)
3465 return;
3466
3467 if (v->flags & VM_UNINITIALIZED)
3468 return;
3469 /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
3470 smp_rmb();
3471
3472 memset(counters, 0, nr_node_ids * sizeof(unsigned int));
3473
3474 for (nr = 0; nr < v->nr_pages; nr++)
3475 counters[page_to_nid(v->pages[nr])]++;
3476
3477 for_each_node_state(nr, N_HIGH_MEMORY)
3478 if (counters[nr])
3479 seq_printf(m, " N%u=%u", nr, counters[nr]);
3480 }
3481}
3482
3483static void show_purge_info(struct seq_file *m)
3484{
3485 struct llist_node *head;
3486 struct vmap_area *va;
3487
3488 head = READ_ONCE(vmap_purge_list.first);
3489 if (head == NULL)
3490 return;
3491
3492 llist_for_each_entry(va, head, purge_list) {
3493 seq_printf(m, "0x%pK-0x%pK %7ld unpurged vm_area\n",
3494 (void *)va->va_start, (void *)va->va_end,
3495 va->va_end - va->va_start);
3496 }
3497}
3498
3499static int s_show(struct seq_file *m, void *p)
3500{
3501 struct vmap_area *va;
3502 struct vm_struct *v;
3503
3504 va = list_entry(p, struct vmap_area, list);
3505
3506 /*
3507 * s_show can encounter race with remove_vm_area, !vm on behalf
3508 * of vmap area is being tear down or vm_map_ram allocation.
3509 */
3510 if (!va->vm) {
3511 seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
3512 (void *)va->va_start, (void *)va->va_end,
3513 va->va_end - va->va_start);
3514
3515 return 0;
3516 }
3517
3518 v = va->vm;
3519
3520 seq_printf(m, "0x%pK-0x%pK %7ld",
3521 v->addr, v->addr + v->size, v->size);
3522
3523 if (v->caller)
3524 seq_printf(m, " %pS", v->caller);
3525
3526 if (v->nr_pages)
3527 seq_printf(m, " pages=%d", v->nr_pages);
3528
3529 if (v->phys_addr)
3530 seq_printf(m, " phys=%pa", &v->phys_addr);
3531
3532 if (v->flags & VM_IOREMAP)
3533 seq_puts(m, " ioremap");
3534
3535 if (v->flags & VM_ALLOC)
3536 seq_puts(m, " vmalloc");
3537
3538 if (v->flags & VM_MAP)
3539 seq_puts(m, " vmap");
3540
3541 if (v->flags & VM_USERMAP)
3542 seq_puts(m, " user");
3543
3544 if (v->flags & VM_DMA_COHERENT)
3545 seq_puts(m, " dma-coherent");
3546
3547 if (is_vmalloc_addr(v->pages))
3548 seq_puts(m, " vpages");
3549
3550 show_numa_info(m, v);
3551 seq_putc(m, '\n');
3552
3553 /*
3554 * As a final step, dump "unpurged" areas. Note,
3555 * that entire "/proc/vmallocinfo" output will not
3556 * be address sorted, because the purge list is not
3557 * sorted.
3558 */
3559 if (list_is_last(&va->list, &vmap_area_list))
3560 show_purge_info(m);
3561
3562 return 0;
3563}
3564
3565static const struct seq_operations vmalloc_op = {
3566 .start = s_start,
3567 .next = s_next,
3568 .stop = s_stop,
3569 .show = s_show,
3570};
3571
3572static int __init proc_vmalloc_init(void)
3573{
3574 if (IS_ENABLED(CONFIG_NUMA))
3575 proc_create_seq_private("vmallocinfo", 0400, NULL,
3576 &vmalloc_op,
3577 nr_node_ids * sizeof(unsigned int), NULL);
3578 else
3579 proc_create_seq("vmallocinfo", 0400, NULL, &vmalloc_op);
3580 return 0;
3581}
3582module_init(proc_vmalloc_init);
3583
3584#endif
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/signal.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/notifier.h>
25#include <linux/rbtree.h>
26#include <linux/radix-tree.h>
27#include <linux/rcupdate.h>
28#include <linux/pfn.h>
29#include <linux/kmemleak.h>
30#include <linux/atomic.h>
31#include <linux/compiler.h>
32#include <linux/llist.h>
33#include <linux/bitops.h>
34
35#include <linux/uaccess.h>
36#include <asm/tlbflush.h>
37#include <asm/shmparam.h>
38
39#include "internal.h"
40
41struct vfree_deferred {
42 struct llist_head list;
43 struct work_struct wq;
44};
45static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
46
47static void __vunmap(const void *, int);
48
49static void free_work(struct work_struct *w)
50{
51 struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
52 struct llist_node *t, *llnode;
53
54 llist_for_each_safe(llnode, t, llist_del_all(&p->list))
55 __vunmap((void *)llnode, 1);
56}
57
58/*** Page table manipulation functions ***/
59
60static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
61{
62 pte_t *pte;
63
64 pte = pte_offset_kernel(pmd, addr);
65 do {
66 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
67 WARN_ON(!pte_none(ptent) && !pte_present(ptent));
68 } while (pte++, addr += PAGE_SIZE, addr != end);
69}
70
71static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end)
72{
73 pmd_t *pmd;
74 unsigned long next;
75
76 pmd = pmd_offset(pud, addr);
77 do {
78 next = pmd_addr_end(addr, end);
79 if (pmd_clear_huge(pmd))
80 continue;
81 if (pmd_none_or_clear_bad(pmd))
82 continue;
83 vunmap_pte_range(pmd, addr, next);
84 } while (pmd++, addr = next, addr != end);
85}
86
87static void vunmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end)
88{
89 pud_t *pud;
90 unsigned long next;
91
92 pud = pud_offset(p4d, addr);
93 do {
94 next = pud_addr_end(addr, end);
95 if (pud_clear_huge(pud))
96 continue;
97 if (pud_none_or_clear_bad(pud))
98 continue;
99 vunmap_pmd_range(pud, addr, next);
100 } while (pud++, addr = next, addr != end);
101}
102
103static void vunmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end)
104{
105 p4d_t *p4d;
106 unsigned long next;
107
108 p4d = p4d_offset(pgd, addr);
109 do {
110 next = p4d_addr_end(addr, end);
111 if (p4d_clear_huge(p4d))
112 continue;
113 if (p4d_none_or_clear_bad(p4d))
114 continue;
115 vunmap_pud_range(p4d, addr, next);
116 } while (p4d++, addr = next, addr != end);
117}
118
119static void vunmap_page_range(unsigned long addr, unsigned long end)
120{
121 pgd_t *pgd;
122 unsigned long next;
123
124 BUG_ON(addr >= end);
125 pgd = pgd_offset_k(addr);
126 do {
127 next = pgd_addr_end(addr, end);
128 if (pgd_none_or_clear_bad(pgd))
129 continue;
130 vunmap_p4d_range(pgd, addr, next);
131 } while (pgd++, addr = next, addr != end);
132}
133
134static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
135 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
136{
137 pte_t *pte;
138
139 /*
140 * nr is a running index into the array which helps higher level
141 * callers keep track of where we're up to.
142 */
143
144 pte = pte_alloc_kernel(pmd, addr);
145 if (!pte)
146 return -ENOMEM;
147 do {
148 struct page *page = pages[*nr];
149
150 if (WARN_ON(!pte_none(*pte)))
151 return -EBUSY;
152 if (WARN_ON(!page))
153 return -ENOMEM;
154 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
155 (*nr)++;
156 } while (pte++, addr += PAGE_SIZE, addr != end);
157 return 0;
158}
159
160static int vmap_pmd_range(pud_t *pud, unsigned long addr,
161 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
162{
163 pmd_t *pmd;
164 unsigned long next;
165
166 pmd = pmd_alloc(&init_mm, pud, addr);
167 if (!pmd)
168 return -ENOMEM;
169 do {
170 next = pmd_addr_end(addr, end);
171 if (vmap_pte_range(pmd, addr, next, prot, pages, nr))
172 return -ENOMEM;
173 } while (pmd++, addr = next, addr != end);
174 return 0;
175}
176
177static int vmap_pud_range(p4d_t *p4d, unsigned long addr,
178 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
179{
180 pud_t *pud;
181 unsigned long next;
182
183 pud = pud_alloc(&init_mm, p4d, addr);
184 if (!pud)
185 return -ENOMEM;
186 do {
187 next = pud_addr_end(addr, end);
188 if (vmap_pmd_range(pud, addr, next, prot, pages, nr))
189 return -ENOMEM;
190 } while (pud++, addr = next, addr != end);
191 return 0;
192}
193
194static int vmap_p4d_range(pgd_t *pgd, unsigned long addr,
195 unsigned long end, pgprot_t prot, struct page **pages, int *nr)
196{
197 p4d_t *p4d;
198 unsigned long next;
199
200 p4d = p4d_alloc(&init_mm, pgd, addr);
201 if (!p4d)
202 return -ENOMEM;
203 do {
204 next = p4d_addr_end(addr, end);
205 if (vmap_pud_range(p4d, addr, next, prot, pages, nr))
206 return -ENOMEM;
207 } while (p4d++, addr = next, addr != end);
208 return 0;
209}
210
211/*
212 * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and
213 * will have pfns corresponding to the "pages" array.
214 *
215 * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N]
216 */
217static int vmap_page_range_noflush(unsigned long start, unsigned long end,
218 pgprot_t prot, struct page **pages)
219{
220 pgd_t *pgd;
221 unsigned long next;
222 unsigned long addr = start;
223 int err = 0;
224 int nr = 0;
225
226 BUG_ON(addr >= end);
227 pgd = pgd_offset_k(addr);
228 do {
229 next = pgd_addr_end(addr, end);
230 err = vmap_p4d_range(pgd, addr, next, prot, pages, &nr);
231 if (err)
232 return err;
233 } while (pgd++, addr = next, addr != end);
234
235 return nr;
236}
237
238static int vmap_page_range(unsigned long start, unsigned long end,
239 pgprot_t prot, struct page **pages)
240{
241 int ret;
242
243 ret = vmap_page_range_noflush(start, end, prot, pages);
244 flush_cache_vmap(start, end);
245 return ret;
246}
247
248int is_vmalloc_or_module_addr(const void *x)
249{
250 /*
251 * ARM, x86-64 and sparc64 put modules in a special place,
252 * and fall back on vmalloc() if that fails. Others
253 * just put it in the vmalloc space.
254 */
255#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
256 unsigned long addr = (unsigned long)x;
257 if (addr >= MODULES_VADDR && addr < MODULES_END)
258 return 1;
259#endif
260 return is_vmalloc_addr(x);
261}
262
263/*
264 * Walk a vmap address to the struct page it maps.
265 */
266struct page *vmalloc_to_page(const void *vmalloc_addr)
267{
268 unsigned long addr = (unsigned long) vmalloc_addr;
269 struct page *page = NULL;
270 pgd_t *pgd = pgd_offset_k(addr);
271 p4d_t *p4d;
272 pud_t *pud;
273 pmd_t *pmd;
274 pte_t *ptep, pte;
275
276 /*
277 * XXX we might need to change this if we add VIRTUAL_BUG_ON for
278 * architectures that do not vmalloc module space
279 */
280 VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
281
282 if (pgd_none(*pgd))
283 return NULL;
284 p4d = p4d_offset(pgd, addr);
285 if (p4d_none(*p4d))
286 return NULL;
287 pud = pud_offset(p4d, addr);
288
289 /*
290 * Don't dereference bad PUD or PMD (below) entries. This will also
291 * identify huge mappings, which we may encounter on architectures
292 * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be
293 * identified as vmalloc addresses by is_vmalloc_addr(), but are
294 * not [unambiguously] associated with a struct page, so there is
295 * no correct value to return for them.
296 */
297 WARN_ON_ONCE(pud_bad(*pud));
298 if (pud_none(*pud) || pud_bad(*pud))
299 return NULL;
300 pmd = pmd_offset(pud, addr);
301 WARN_ON_ONCE(pmd_bad(*pmd));
302 if (pmd_none(*pmd) || pmd_bad(*pmd))
303 return NULL;
304
305 ptep = pte_offset_map(pmd, addr);
306 pte = *ptep;
307 if (pte_present(pte))
308 page = pte_page(pte);
309 pte_unmap(ptep);
310 return page;
311}
312EXPORT_SYMBOL(vmalloc_to_page);
313
314/*
315 * Map a vmalloc()-space virtual address to the physical page frame number.
316 */
317unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
318{
319 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
320}
321EXPORT_SYMBOL(vmalloc_to_pfn);
322
323
324/*** Global kva allocator ***/
325
326#define VM_LAZY_FREE 0x02
327#define VM_VM_AREA 0x04
328
329static DEFINE_SPINLOCK(vmap_area_lock);
330/* Export for kexec only */
331LIST_HEAD(vmap_area_list);
332static LLIST_HEAD(vmap_purge_list);
333static struct rb_root vmap_area_root = RB_ROOT;
334
335/* The vmap cache globals are protected by vmap_area_lock */
336static struct rb_node *free_vmap_cache;
337static unsigned long cached_hole_size;
338static unsigned long cached_vstart;
339static unsigned long cached_align;
340
341static unsigned long vmap_area_pcpu_hole;
342
343static struct vmap_area *__find_vmap_area(unsigned long addr)
344{
345 struct rb_node *n = vmap_area_root.rb_node;
346
347 while (n) {
348 struct vmap_area *va;
349
350 va = rb_entry(n, struct vmap_area, rb_node);
351 if (addr < va->va_start)
352 n = n->rb_left;
353 else if (addr >= va->va_end)
354 n = n->rb_right;
355 else
356 return va;
357 }
358
359 return NULL;
360}
361
362static void __insert_vmap_area(struct vmap_area *va)
363{
364 struct rb_node **p = &vmap_area_root.rb_node;
365 struct rb_node *parent = NULL;
366 struct rb_node *tmp;
367
368 while (*p) {
369 struct vmap_area *tmp_va;
370
371 parent = *p;
372 tmp_va = rb_entry(parent, struct vmap_area, rb_node);
373 if (va->va_start < tmp_va->va_end)
374 p = &(*p)->rb_left;
375 else if (va->va_end > tmp_va->va_start)
376 p = &(*p)->rb_right;
377 else
378 BUG();
379 }
380
381 rb_link_node(&va->rb_node, parent, p);
382 rb_insert_color(&va->rb_node, &vmap_area_root);
383
384 /* address-sort this list */
385 tmp = rb_prev(&va->rb_node);
386 if (tmp) {
387 struct vmap_area *prev;
388 prev = rb_entry(tmp, struct vmap_area, rb_node);
389 list_add_rcu(&va->list, &prev->list);
390 } else
391 list_add_rcu(&va->list, &vmap_area_list);
392}
393
394static void purge_vmap_area_lazy(void);
395
396static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
397
398/*
399 * Allocate a region of KVA of the specified size and alignment, within the
400 * vstart and vend.
401 */
402static struct vmap_area *alloc_vmap_area(unsigned long size,
403 unsigned long align,
404 unsigned long vstart, unsigned long vend,
405 int node, gfp_t gfp_mask)
406{
407 struct vmap_area *va;
408 struct rb_node *n;
409 unsigned long addr;
410 int purged = 0;
411 struct vmap_area *first;
412
413 BUG_ON(!size);
414 BUG_ON(offset_in_page(size));
415 BUG_ON(!is_power_of_2(align));
416
417 might_sleep();
418
419 va = kmalloc_node(sizeof(struct vmap_area),
420 gfp_mask & GFP_RECLAIM_MASK, node);
421 if (unlikely(!va))
422 return ERR_PTR(-ENOMEM);
423
424 /*
425 * Only scan the relevant parts containing pointers to other objects
426 * to avoid false negatives.
427 */
428 kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK);
429
430retry:
431 spin_lock(&vmap_area_lock);
432 /*
433 * Invalidate cache if we have more permissive parameters.
434 * cached_hole_size notes the largest hole noticed _below_
435 * the vmap_area cached in free_vmap_cache: if size fits
436 * into that hole, we want to scan from vstart to reuse
437 * the hole instead of allocating above free_vmap_cache.
438 * Note that __free_vmap_area may update free_vmap_cache
439 * without updating cached_hole_size or cached_align.
440 */
441 if (!free_vmap_cache ||
442 size < cached_hole_size ||
443 vstart < cached_vstart ||
444 align < cached_align) {
445nocache:
446 cached_hole_size = 0;
447 free_vmap_cache = NULL;
448 }
449 /* record if we encounter less permissive parameters */
450 cached_vstart = vstart;
451 cached_align = align;
452
453 /* find starting point for our search */
454 if (free_vmap_cache) {
455 first = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
456 addr = ALIGN(first->va_end, align);
457 if (addr < vstart)
458 goto nocache;
459 if (addr + size < addr)
460 goto overflow;
461
462 } else {
463 addr = ALIGN(vstart, align);
464 if (addr + size < addr)
465 goto overflow;
466
467 n = vmap_area_root.rb_node;
468 first = NULL;
469
470 while (n) {
471 struct vmap_area *tmp;
472 tmp = rb_entry(n, struct vmap_area, rb_node);
473 if (tmp->va_end >= addr) {
474 first = tmp;
475 if (tmp->va_start <= addr)
476 break;
477 n = n->rb_left;
478 } else
479 n = n->rb_right;
480 }
481
482 if (!first)
483 goto found;
484 }
485
486 /* from the starting point, walk areas until a suitable hole is found */
487 while (addr + size > first->va_start && addr + size <= vend) {
488 if (addr + cached_hole_size < first->va_start)
489 cached_hole_size = first->va_start - addr;
490 addr = ALIGN(first->va_end, align);
491 if (addr + size < addr)
492 goto overflow;
493
494 if (list_is_last(&first->list, &vmap_area_list))
495 goto found;
496
497 first = list_next_entry(first, list);
498 }
499
500found:
501 if (addr + size > vend)
502 goto overflow;
503
504 va->va_start = addr;
505 va->va_end = addr + size;
506 va->flags = 0;
507 __insert_vmap_area(va);
508 free_vmap_cache = &va->rb_node;
509 spin_unlock(&vmap_area_lock);
510
511 BUG_ON(!IS_ALIGNED(va->va_start, align));
512 BUG_ON(va->va_start < vstart);
513 BUG_ON(va->va_end > vend);
514
515 return va;
516
517overflow:
518 spin_unlock(&vmap_area_lock);
519 if (!purged) {
520 purge_vmap_area_lazy();
521 purged = 1;
522 goto retry;
523 }
524
525 if (gfpflags_allow_blocking(gfp_mask)) {
526 unsigned long freed = 0;
527 blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
528 if (freed > 0) {
529 purged = 0;
530 goto retry;
531 }
532 }
533
534 if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
535 pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
536 size);
537 kfree(va);
538 return ERR_PTR(-EBUSY);
539}
540
541int register_vmap_purge_notifier(struct notifier_block *nb)
542{
543 return blocking_notifier_chain_register(&vmap_notify_list, nb);
544}
545EXPORT_SYMBOL_GPL(register_vmap_purge_notifier);
546
547int unregister_vmap_purge_notifier(struct notifier_block *nb)
548{
549 return blocking_notifier_chain_unregister(&vmap_notify_list, nb);
550}
551EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier);
552
553static void __free_vmap_area(struct vmap_area *va)
554{
555 BUG_ON(RB_EMPTY_NODE(&va->rb_node));
556
557 if (free_vmap_cache) {
558 if (va->va_end < cached_vstart) {
559 free_vmap_cache = NULL;
560 } else {
561 struct vmap_area *cache;
562 cache = rb_entry(free_vmap_cache, struct vmap_area, rb_node);
563 if (va->va_start <= cache->va_start) {
564 free_vmap_cache = rb_prev(&va->rb_node);
565 /*
566 * We don't try to update cached_hole_size or
567 * cached_align, but it won't go very wrong.
568 */
569 }
570 }
571 }
572 rb_erase(&va->rb_node, &vmap_area_root);
573 RB_CLEAR_NODE(&va->rb_node);
574 list_del_rcu(&va->list);
575
576 /*
577 * Track the highest possible candidate for pcpu area
578 * allocation. Areas outside of vmalloc area can be returned
579 * here too, consider only end addresses which fall inside
580 * vmalloc area proper.
581 */
582 if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
583 vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);
584
585 kfree_rcu(va, rcu_head);
586}
587
588/*
589 * Free a region of KVA allocated by alloc_vmap_area
590 */
591static void free_vmap_area(struct vmap_area *va)
592{
593 spin_lock(&vmap_area_lock);
594 __free_vmap_area(va);
595 spin_unlock(&vmap_area_lock);
596}
597
598/*
599 * Clear the pagetable entries of a given vmap_area
600 */
601static void unmap_vmap_area(struct vmap_area *va)
602{
603 vunmap_page_range(va->va_start, va->va_end);
604}
605
606static void vmap_debug_free_range(unsigned long start, unsigned long end)
607{
608 /*
609 * Unmap page tables and force a TLB flush immediately if pagealloc
610 * debugging is enabled. This catches use after free bugs similarly to
611 * those in linear kernel virtual address space after a page has been
612 * freed.
613 *
614 * All the lazy freeing logic is still retained, in order to minimise
615 * intrusiveness of this debugging feature.
616 *
617 * This is going to be *slow* (linear kernel virtual address debugging
618 * doesn't do a broadcast TLB flush so it is a lot faster).
619 */
620 if (debug_pagealloc_enabled()) {
621 vunmap_page_range(start, end);
622 flush_tlb_kernel_range(start, end);
623 }
624}
625
626/*
627 * lazy_max_pages is the maximum amount of virtual address space we gather up
628 * before attempting to purge with a TLB flush.
629 *
630 * There is a tradeoff here: a larger number will cover more kernel page tables
631 * and take slightly longer to purge, but it will linearly reduce the number of
632 * global TLB flushes that must be performed. It would seem natural to scale
633 * this number up linearly with the number of CPUs (because vmapping activity
634 * could also scale linearly with the number of CPUs), however it is likely
635 * that in practice, workloads might be constrained in other ways that mean
636 * vmap activity will not scale linearly with CPUs. Also, I want to be
637 * conservative and not introduce a big latency on huge systems, so go with
638 * a less aggressive log scale. It will still be an improvement over the old
639 * code, and it will be simple to change the scale factor if we find that it
640 * becomes a problem on bigger systems.
641 */
642static unsigned long lazy_max_pages(void)
643{
644 unsigned int log;
645
646 log = fls(num_online_cpus());
647
648 return log * (32UL * 1024 * 1024 / PAGE_SIZE);
649}
650
651static atomic_t vmap_lazy_nr = ATOMIC_INIT(0);
652
653/*
654 * Serialize vmap purging. There is no actual criticial section protected
655 * by this look, but we want to avoid concurrent calls for performance
656 * reasons and to make the pcpu_get_vm_areas more deterministic.
657 */
658static DEFINE_MUTEX(vmap_purge_lock);
659
660/* for per-CPU blocks */
661static void purge_fragmented_blocks_allcpus(void);
662
663/*
664 * called before a call to iounmap() if the caller wants vm_area_struct's
665 * immediately freed.
666 */
667void set_iounmap_nonlazy(void)
668{
669 atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
670}
671
672/*
673 * Purges all lazily-freed vmap areas.
674 */
675static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
676{
677 struct llist_node *valist;
678 struct vmap_area *va;
679 struct vmap_area *n_va;
680 bool do_free = false;
681
682 lockdep_assert_held(&vmap_purge_lock);
683
684 valist = llist_del_all(&vmap_purge_list);
685 llist_for_each_entry(va, valist, purge_list) {
686 if (va->va_start < start)
687 start = va->va_start;
688 if (va->va_end > end)
689 end = va->va_end;
690 do_free = true;
691 }
692
693 if (!do_free)
694 return false;
695
696 flush_tlb_kernel_range(start, end);
697
698 spin_lock(&vmap_area_lock);
699 llist_for_each_entry_safe(va, n_va, valist, purge_list) {
700 int nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
701
702 __free_vmap_area(va);
703 atomic_sub(nr, &vmap_lazy_nr);
704 cond_resched_lock(&vmap_area_lock);
705 }
706 spin_unlock(&vmap_area_lock);
707 return true;
708}
709
710/*
711 * Kick off a purge of the outstanding lazy areas. Don't bother if somebody
712 * is already purging.
713 */
714static void try_purge_vmap_area_lazy(void)
715{
716 if (mutex_trylock(&vmap_purge_lock)) {
717 __purge_vmap_area_lazy(ULONG_MAX, 0);
718 mutex_unlock(&vmap_purge_lock);
719 }
720}
721
722/*
723 * Kick off a purge of the outstanding lazy areas.
724 */
725static void purge_vmap_area_lazy(void)
726{
727 mutex_lock(&vmap_purge_lock);
728 purge_fragmented_blocks_allcpus();
729 __purge_vmap_area_lazy(ULONG_MAX, 0);
730 mutex_unlock(&vmap_purge_lock);
731}
732
733/*
734 * Free a vmap area, caller ensuring that the area has been unmapped
735 * and flush_cache_vunmap had been called for the correct range
736 * previously.
737 */
738static void free_vmap_area_noflush(struct vmap_area *va)
739{
740 int nr_lazy;
741
742 nr_lazy = atomic_add_return((va->va_end - va->va_start) >> PAGE_SHIFT,
743 &vmap_lazy_nr);
744
745 /* After this point, we may free va at any time */
746 llist_add(&va->purge_list, &vmap_purge_list);
747
748 if (unlikely(nr_lazy > lazy_max_pages()))
749 try_purge_vmap_area_lazy();
750}
751
752/*
753 * Free and unmap a vmap area
754 */
755static void free_unmap_vmap_area(struct vmap_area *va)
756{
757 flush_cache_vunmap(va->va_start, va->va_end);
758 unmap_vmap_area(va);
759 free_vmap_area_noflush(va);
760}
761
762static struct vmap_area *find_vmap_area(unsigned long addr)
763{
764 struct vmap_area *va;
765
766 spin_lock(&vmap_area_lock);
767 va = __find_vmap_area(addr);
768 spin_unlock(&vmap_area_lock);
769
770 return va;
771}
772
773/*** Per cpu kva allocator ***/
774
775/*
776 * vmap space is limited especially on 32 bit architectures. Ensure there is
777 * room for at least 16 percpu vmap blocks per CPU.
778 */
779/*
780 * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
781 * to #define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START). Guess
782 * instead (we just need a rough idea)
783 */
784#if BITS_PER_LONG == 32
785#define VMALLOC_SPACE (128UL*1024*1024)
786#else
787#define VMALLOC_SPACE (128UL*1024*1024*1024)
788#endif
789
790#define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE)
791#define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */
792#define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */
793#define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2)
794#define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */
795#define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */
796#define VMAP_BBMAP_BITS \
797 VMAP_MIN(VMAP_BBMAP_BITS_MAX, \
798 VMAP_MAX(VMAP_BBMAP_BITS_MIN, \
799 VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
800
801#define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
802
803static bool vmap_initialized __read_mostly = false;
804
805struct vmap_block_queue {
806 spinlock_t lock;
807 struct list_head free;
808};
809
810struct vmap_block {
811 spinlock_t lock;
812 struct vmap_area *va;
813 unsigned long free, dirty;
814 unsigned long dirty_min, dirty_max; /*< dirty range */
815 struct list_head free_list;
816 struct rcu_head rcu_head;
817 struct list_head purge;
818};
819
820/* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
821static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
822
823/*
824 * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block
825 * in the free path. Could get rid of this if we change the API to return a
826 * "cookie" from alloc, to be passed to free. But no big deal yet.
827 */
828static DEFINE_SPINLOCK(vmap_block_tree_lock);
829static RADIX_TREE(vmap_block_tree, GFP_ATOMIC);
830
831/*
832 * We should probably have a fallback mechanism to allocate virtual memory
833 * out of partially filled vmap blocks. However vmap block sizing should be
834 * fairly reasonable according to the vmalloc size, so it shouldn't be a
835 * big problem.
836 */
837
838static unsigned long addr_to_vb_idx(unsigned long addr)
839{
840 addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
841 addr /= VMAP_BLOCK_SIZE;
842 return addr;
843}
844
845static void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off)
846{
847 unsigned long addr;
848
849 addr = va_start + (pages_off << PAGE_SHIFT);
850 BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(va_start));
851 return (void *)addr;
852}
853
854/**
855 * new_vmap_block - allocates new vmap_block and occupies 2^order pages in this
856 * block. Of course pages number can't exceed VMAP_BBMAP_BITS
857 * @order: how many 2^order pages should be occupied in newly allocated block
858 * @gfp_mask: flags for the page level allocator
859 *
860 * Returns: virtual address in a newly allocated block or ERR_PTR(-errno)
861 */
862static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
863{
864 struct vmap_block_queue *vbq;
865 struct vmap_block *vb;
866 struct vmap_area *va;
867 unsigned long vb_idx;
868 int node, err;
869 void *vaddr;
870
871 node = numa_node_id();
872
873 vb = kmalloc_node(sizeof(struct vmap_block),
874 gfp_mask & GFP_RECLAIM_MASK, node);
875 if (unlikely(!vb))
876 return ERR_PTR(-ENOMEM);
877
878 va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
879 VMALLOC_START, VMALLOC_END,
880 node, gfp_mask);
881 if (IS_ERR(va)) {
882 kfree(vb);
883 return ERR_CAST(va);
884 }
885
886 err = radix_tree_preload(gfp_mask);
887 if (unlikely(err)) {
888 kfree(vb);
889 free_vmap_area(va);
890 return ERR_PTR(err);
891 }
892
893 vaddr = vmap_block_vaddr(va->va_start, 0);
894 spin_lock_init(&vb->lock);
895 vb->va = va;
896 /* At least something should be left free */
897 BUG_ON(VMAP_BBMAP_BITS <= (1UL << order));
898 vb->free = VMAP_BBMAP_BITS - (1UL << order);
899 vb->dirty = 0;
900 vb->dirty_min = VMAP_BBMAP_BITS;
901 vb->dirty_max = 0;
902 INIT_LIST_HEAD(&vb->free_list);
903
904 vb_idx = addr_to_vb_idx(va->va_start);
905 spin_lock(&vmap_block_tree_lock);
906 err = radix_tree_insert(&vmap_block_tree, vb_idx, vb);
907 spin_unlock(&vmap_block_tree_lock);
908 BUG_ON(err);
909 radix_tree_preload_end();
910
911 vbq = &get_cpu_var(vmap_block_queue);
912 spin_lock(&vbq->lock);
913 list_add_tail_rcu(&vb->free_list, &vbq->free);
914 spin_unlock(&vbq->lock);
915 put_cpu_var(vmap_block_queue);
916
917 return vaddr;
918}
919
920static void free_vmap_block(struct vmap_block *vb)
921{
922 struct vmap_block *tmp;
923 unsigned long vb_idx;
924
925 vb_idx = addr_to_vb_idx(vb->va->va_start);
926 spin_lock(&vmap_block_tree_lock);
927 tmp = radix_tree_delete(&vmap_block_tree, vb_idx);
928 spin_unlock(&vmap_block_tree_lock);
929 BUG_ON(tmp != vb);
930
931 free_vmap_area_noflush(vb->va);
932 kfree_rcu(vb, rcu_head);
933}
934
935static void purge_fragmented_blocks(int cpu)
936{
937 LIST_HEAD(purge);
938 struct vmap_block *vb;
939 struct vmap_block *n_vb;
940 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
941
942 rcu_read_lock();
943 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
944
945 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
946 continue;
947
948 spin_lock(&vb->lock);
949 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
950 vb->free = 0; /* prevent further allocs after releasing lock */
951 vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
952 vb->dirty_min = 0;
953 vb->dirty_max = VMAP_BBMAP_BITS;
954 spin_lock(&vbq->lock);
955 list_del_rcu(&vb->free_list);
956 spin_unlock(&vbq->lock);
957 spin_unlock(&vb->lock);
958 list_add_tail(&vb->purge, &purge);
959 } else
960 spin_unlock(&vb->lock);
961 }
962 rcu_read_unlock();
963
964 list_for_each_entry_safe(vb, n_vb, &purge, purge) {
965 list_del(&vb->purge);
966 free_vmap_block(vb);
967 }
968}
969
970static void purge_fragmented_blocks_allcpus(void)
971{
972 int cpu;
973
974 for_each_possible_cpu(cpu)
975 purge_fragmented_blocks(cpu);
976}
977
978static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
979{
980 struct vmap_block_queue *vbq;
981 struct vmap_block *vb;
982 void *vaddr = NULL;
983 unsigned int order;
984
985 BUG_ON(offset_in_page(size));
986 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
987 if (WARN_ON(size == 0)) {
988 /*
989 * Allocating 0 bytes isn't what caller wants since
990 * get_order(0) returns funny result. Just warn and terminate
991 * early.
992 */
993 return NULL;
994 }
995 order = get_order(size);
996
997 rcu_read_lock();
998 vbq = &get_cpu_var(vmap_block_queue);
999 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1000 unsigned long pages_off;
1001
1002 spin_lock(&vb->lock);
1003 if (vb->free < (1UL << order)) {
1004 spin_unlock(&vb->lock);
1005 continue;
1006 }
1007
1008 pages_off = VMAP_BBMAP_BITS - vb->free;
1009 vaddr = vmap_block_vaddr(vb->va->va_start, pages_off);
1010 vb->free -= 1UL << order;
1011 if (vb->free == 0) {
1012 spin_lock(&vbq->lock);
1013 list_del_rcu(&vb->free_list);
1014 spin_unlock(&vbq->lock);
1015 }
1016
1017 spin_unlock(&vb->lock);
1018 break;
1019 }
1020
1021 put_cpu_var(vmap_block_queue);
1022 rcu_read_unlock();
1023
1024 /* Allocate new block if nothing was found */
1025 if (!vaddr)
1026 vaddr = new_vmap_block(order, gfp_mask);
1027
1028 return vaddr;
1029}
1030
1031static void vb_free(const void *addr, unsigned long size)
1032{
1033 unsigned long offset;
1034 unsigned long vb_idx;
1035 unsigned int order;
1036 struct vmap_block *vb;
1037
1038 BUG_ON(offset_in_page(size));
1039 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
1040
1041 flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size);
1042
1043 order = get_order(size);
1044
1045 offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1);
1046 offset >>= PAGE_SHIFT;
1047
1048 vb_idx = addr_to_vb_idx((unsigned long)addr);
1049 rcu_read_lock();
1050 vb = radix_tree_lookup(&vmap_block_tree, vb_idx);
1051 rcu_read_unlock();
1052 BUG_ON(!vb);
1053
1054 vunmap_page_range((unsigned long)addr, (unsigned long)addr + size);
1055
1056 spin_lock(&vb->lock);
1057
1058 /* Expand dirty range */
1059 vb->dirty_min = min(vb->dirty_min, offset);
1060 vb->dirty_max = max(vb->dirty_max, offset + (1UL << order));
1061
1062 vb->dirty += 1UL << order;
1063 if (vb->dirty == VMAP_BBMAP_BITS) {
1064 BUG_ON(vb->free);
1065 spin_unlock(&vb->lock);
1066 free_vmap_block(vb);
1067 } else
1068 spin_unlock(&vb->lock);
1069}
1070
1071/**
1072 * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
1073 *
1074 * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
1075 * to amortize TLB flushing overheads. What this means is that any page you
1076 * have now, may, in a former life, have been mapped into kernel virtual
1077 * address by the vmap layer and so there might be some CPUs with TLB entries
1078 * still referencing that page (additional to the regular 1:1 kernel mapping).
1079 *
1080 * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
1081 * be sure that none of the pages we have control over will have any aliases
1082 * from the vmap layer.
1083 */
1084void vm_unmap_aliases(void)
1085{
1086 unsigned long start = ULONG_MAX, end = 0;
1087 int cpu;
1088 int flush = 0;
1089
1090 if (unlikely(!vmap_initialized))
1091 return;
1092
1093 might_sleep();
1094
1095 for_each_possible_cpu(cpu) {
1096 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
1097 struct vmap_block *vb;
1098
1099 rcu_read_lock();
1100 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
1101 spin_lock(&vb->lock);
1102 if (vb->dirty) {
1103 unsigned long va_start = vb->va->va_start;
1104 unsigned long s, e;
1105
1106 s = va_start + (vb->dirty_min << PAGE_SHIFT);
1107 e = va_start + (vb->dirty_max << PAGE_SHIFT);
1108
1109 start = min(s, start);
1110 end = max(e, end);
1111
1112 flush = 1;
1113 }
1114 spin_unlock(&vb->lock);
1115 }
1116 rcu_read_unlock();
1117 }
1118
1119 mutex_lock(&vmap_purge_lock);
1120 purge_fragmented_blocks_allcpus();
1121 if (!__purge_vmap_area_lazy(start, end) && flush)
1122 flush_tlb_kernel_range(start, end);
1123 mutex_unlock(&vmap_purge_lock);
1124}
1125EXPORT_SYMBOL_GPL(vm_unmap_aliases);
1126
1127/**
1128 * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
1129 * @mem: the pointer returned by vm_map_ram
1130 * @count: the count passed to that vm_map_ram call (cannot unmap partial)
1131 */
1132void vm_unmap_ram(const void *mem, unsigned int count)
1133{
1134 unsigned long size = (unsigned long)count << PAGE_SHIFT;
1135 unsigned long addr = (unsigned long)mem;
1136 struct vmap_area *va;
1137
1138 might_sleep();
1139 BUG_ON(!addr);
1140 BUG_ON(addr < VMALLOC_START);
1141 BUG_ON(addr > VMALLOC_END);
1142 BUG_ON(!PAGE_ALIGNED(addr));
1143
1144 debug_check_no_locks_freed(mem, size);
1145 vmap_debug_free_range(addr, addr+size);
1146
1147 if (likely(count <= VMAP_MAX_ALLOC)) {
1148 vb_free(mem, size);
1149 return;
1150 }
1151
1152 va = find_vmap_area(addr);
1153 BUG_ON(!va);
1154 free_unmap_vmap_area(va);
1155}
1156EXPORT_SYMBOL(vm_unmap_ram);
1157
1158/**
1159 * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
1160 * @pages: an array of pointers to the pages to be mapped
1161 * @count: number of pages
1162 * @node: prefer to allocate data structures on this node
1163 * @prot: memory protection to use. PAGE_KERNEL for regular RAM
1164 *
1165 * If you use this function for less than VMAP_MAX_ALLOC pages, it could be
1166 * faster than vmap so it's good. But if you mix long-life and short-life
1167 * objects with vm_map_ram(), it could consume lots of address space through
1168 * fragmentation (especially on a 32bit machine). You could see failures in
1169 * the end. Please use this function for short-lived objects.
1170 *
1171 * Returns: a pointer to the address that has been mapped, or %NULL on failure
1172 */
1173void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
1174{
1175 unsigned long size = (unsigned long)count << PAGE_SHIFT;
1176 unsigned long addr;
1177 void *mem;
1178
1179 if (likely(count <= VMAP_MAX_ALLOC)) {
1180 mem = vb_alloc(size, GFP_KERNEL);
1181 if (IS_ERR(mem))
1182 return NULL;
1183 addr = (unsigned long)mem;
1184 } else {
1185 struct vmap_area *va;
1186 va = alloc_vmap_area(size, PAGE_SIZE,
1187 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
1188 if (IS_ERR(va))
1189 return NULL;
1190
1191 addr = va->va_start;
1192 mem = (void *)addr;
1193 }
1194 if (vmap_page_range(addr, addr + size, prot, pages) < 0) {
1195 vm_unmap_ram(mem, count);
1196 return NULL;
1197 }
1198 return mem;
1199}
1200EXPORT_SYMBOL(vm_map_ram);
1201
1202static struct vm_struct *vmlist __initdata;
1203/**
1204 * vm_area_add_early - add vmap area early during boot
1205 * @vm: vm_struct to add
1206 *
1207 * This function is used to add fixed kernel vm area to vmlist before
1208 * vmalloc_init() is called. @vm->addr, @vm->size, and @vm->flags
1209 * should contain proper values and the other fields should be zero.
1210 *
1211 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1212 */
1213void __init vm_area_add_early(struct vm_struct *vm)
1214{
1215 struct vm_struct *tmp, **p;
1216
1217 BUG_ON(vmap_initialized);
1218 for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
1219 if (tmp->addr >= vm->addr) {
1220 BUG_ON(tmp->addr < vm->addr + vm->size);
1221 break;
1222 } else
1223 BUG_ON(tmp->addr + tmp->size > vm->addr);
1224 }
1225 vm->next = *p;
1226 *p = vm;
1227}
1228
1229/**
1230 * vm_area_register_early - register vmap area early during boot
1231 * @vm: vm_struct to register
1232 * @align: requested alignment
1233 *
1234 * This function is used to register kernel vm area before
1235 * vmalloc_init() is called. @vm->size and @vm->flags should contain
1236 * proper values on entry and other fields should be zero. On return,
1237 * vm->addr contains the allocated address.
1238 *
1239 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
1240 */
1241void __init vm_area_register_early(struct vm_struct *vm, size_t align)
1242{
1243 static size_t vm_init_off __initdata;
1244 unsigned long addr;
1245
1246 addr = ALIGN(VMALLOC_START + vm_init_off, align);
1247 vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START;
1248
1249 vm->addr = (void *)addr;
1250
1251 vm_area_add_early(vm);
1252}
1253
1254void __init vmalloc_init(void)
1255{
1256 struct vmap_area *va;
1257 struct vm_struct *tmp;
1258 int i;
1259
1260 for_each_possible_cpu(i) {
1261 struct vmap_block_queue *vbq;
1262 struct vfree_deferred *p;
1263
1264 vbq = &per_cpu(vmap_block_queue, i);
1265 spin_lock_init(&vbq->lock);
1266 INIT_LIST_HEAD(&vbq->free);
1267 p = &per_cpu(vfree_deferred, i);
1268 init_llist_head(&p->list);
1269 INIT_WORK(&p->wq, free_work);
1270 }
1271
1272 /* Import existing vmlist entries. */
1273 for (tmp = vmlist; tmp; tmp = tmp->next) {
1274 va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT);
1275 va->flags = VM_VM_AREA;
1276 va->va_start = (unsigned long)tmp->addr;
1277 va->va_end = va->va_start + tmp->size;
1278 va->vm = tmp;
1279 __insert_vmap_area(va);
1280 }
1281
1282 vmap_area_pcpu_hole = VMALLOC_END;
1283
1284 vmap_initialized = true;
1285}
1286
1287/**
1288 * map_kernel_range_noflush - map kernel VM area with the specified pages
1289 * @addr: start of the VM area to map
1290 * @size: size of the VM area to map
1291 * @prot: page protection flags to use
1292 * @pages: pages to map
1293 *
1294 * Map PFN_UP(@size) pages at @addr. The VM area @addr and @size
1295 * specify should have been allocated using get_vm_area() and its
1296 * friends.
1297 *
1298 * NOTE:
1299 * This function does NOT do any cache flushing. The caller is
1300 * responsible for calling flush_cache_vmap() on to-be-mapped areas
1301 * before calling this function.
1302 *
1303 * RETURNS:
1304 * The number of pages mapped on success, -errno on failure.
1305 */
1306int map_kernel_range_noflush(unsigned long addr, unsigned long size,
1307 pgprot_t prot, struct page **pages)
1308{
1309 return vmap_page_range_noflush(addr, addr + size, prot, pages);
1310}
1311
1312/**
1313 * unmap_kernel_range_noflush - unmap kernel VM area
1314 * @addr: start of the VM area to unmap
1315 * @size: size of the VM area to unmap
1316 *
1317 * Unmap PFN_UP(@size) pages at @addr. The VM area @addr and @size
1318 * specify should have been allocated using get_vm_area() and its
1319 * friends.
1320 *
1321 * NOTE:
1322 * This function does NOT do any cache flushing. The caller is
1323 * responsible for calling flush_cache_vunmap() on to-be-mapped areas
1324 * before calling this function and flush_tlb_kernel_range() after.
1325 */
1326void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
1327{
1328 vunmap_page_range(addr, addr + size);
1329}
1330EXPORT_SYMBOL_GPL(unmap_kernel_range_noflush);
1331
1332/**
1333 * unmap_kernel_range - unmap kernel VM area and flush cache and TLB
1334 * @addr: start of the VM area to unmap
1335 * @size: size of the VM area to unmap
1336 *
1337 * Similar to unmap_kernel_range_noflush() but flushes vcache before
1338 * the unmapping and tlb after.
1339 */
1340void unmap_kernel_range(unsigned long addr, unsigned long size)
1341{
1342 unsigned long end = addr + size;
1343
1344 flush_cache_vunmap(addr, end);
1345 vunmap_page_range(addr, end);
1346 flush_tlb_kernel_range(addr, end);
1347}
1348EXPORT_SYMBOL_GPL(unmap_kernel_range);
1349
1350int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page **pages)
1351{
1352 unsigned long addr = (unsigned long)area->addr;
1353 unsigned long end = addr + get_vm_area_size(area);
1354 int err;
1355
1356 err = vmap_page_range(addr, end, prot, pages);
1357
1358 return err > 0 ? 0 : err;
1359}
1360EXPORT_SYMBOL_GPL(map_vm_area);
1361
1362static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
1363 unsigned long flags, const void *caller)
1364{
1365 spin_lock(&vmap_area_lock);
1366 vm->flags = flags;
1367 vm->addr = (void *)va->va_start;
1368 vm->size = va->va_end - va->va_start;
1369 vm->caller = caller;
1370 va->vm = vm;
1371 va->flags |= VM_VM_AREA;
1372 spin_unlock(&vmap_area_lock);
1373}
1374
1375static void clear_vm_uninitialized_flag(struct vm_struct *vm)
1376{
1377 /*
1378 * Before removing VM_UNINITIALIZED,
1379 * we should make sure that vm has proper values.
1380 * Pair with smp_rmb() in show_numa_info().
1381 */
1382 smp_wmb();
1383 vm->flags &= ~VM_UNINITIALIZED;
1384}
1385
1386static struct vm_struct *__get_vm_area_node(unsigned long size,
1387 unsigned long align, unsigned long flags, unsigned long start,
1388 unsigned long end, int node, gfp_t gfp_mask, const void *caller)
1389{
1390 struct vmap_area *va;
1391 struct vm_struct *area;
1392
1393 BUG_ON(in_interrupt());
1394 size = PAGE_ALIGN(size);
1395 if (unlikely(!size))
1396 return NULL;
1397
1398 if (flags & VM_IOREMAP)
1399 align = 1ul << clamp_t(int, get_count_order_long(size),
1400 PAGE_SHIFT, IOREMAP_MAX_ORDER);
1401
1402 area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
1403 if (unlikely(!area))
1404 return NULL;
1405
1406 if (!(flags & VM_NO_GUARD))
1407 size += PAGE_SIZE;
1408
1409 va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
1410 if (IS_ERR(va)) {
1411 kfree(area);
1412 return NULL;
1413 }
1414
1415 setup_vmalloc_vm(area, va, flags, caller);
1416
1417 return area;
1418}
1419
1420struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
1421 unsigned long start, unsigned long end)
1422{
1423 return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1424 GFP_KERNEL, __builtin_return_address(0));
1425}
1426EXPORT_SYMBOL_GPL(__get_vm_area);
1427
1428struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
1429 unsigned long start, unsigned long end,
1430 const void *caller)
1431{
1432 return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE,
1433 GFP_KERNEL, caller);
1434}
1435
1436/**
1437 * get_vm_area - reserve a contiguous kernel virtual area
1438 * @size: size of the area
1439 * @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC
1440 *
1441 * Search an area of @size in the kernel virtual mapping area,
1442 * and reserved it for out purposes. Returns the area descriptor
1443 * on success or %NULL on failure.
1444 */
1445struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
1446{
1447 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1448 NUMA_NO_NODE, GFP_KERNEL,
1449 __builtin_return_address(0));
1450}
1451
1452struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
1453 const void *caller)
1454{
1455 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
1456 NUMA_NO_NODE, GFP_KERNEL, caller);
1457}
1458
1459/**
1460 * find_vm_area - find a continuous kernel virtual area
1461 * @addr: base address
1462 *
1463 * Search for the kernel VM area starting at @addr, and return it.
1464 * It is up to the caller to do all required locking to keep the returned
1465 * pointer valid.
1466 */
1467struct vm_struct *find_vm_area(const void *addr)
1468{
1469 struct vmap_area *va;
1470
1471 va = find_vmap_area((unsigned long)addr);
1472 if (va && va->flags & VM_VM_AREA)
1473 return va->vm;
1474
1475 return NULL;
1476}
1477
1478/**
1479 * remove_vm_area - find and remove a continuous kernel virtual area
1480 * @addr: base address
1481 *
1482 * Search for the kernel VM area starting at @addr, and remove it.
1483 * This function returns the found VM area, but using it is NOT safe
1484 * on SMP machines, except for its size or flags.
1485 */
1486struct vm_struct *remove_vm_area(const void *addr)
1487{
1488 struct vmap_area *va;
1489
1490 might_sleep();
1491
1492 va = find_vmap_area((unsigned long)addr);
1493 if (va && va->flags & VM_VM_AREA) {
1494 struct vm_struct *vm = va->vm;
1495
1496 spin_lock(&vmap_area_lock);
1497 va->vm = NULL;
1498 va->flags &= ~VM_VM_AREA;
1499 va->flags |= VM_LAZY_FREE;
1500 spin_unlock(&vmap_area_lock);
1501
1502 vmap_debug_free_range(va->va_start, va->va_end);
1503 kasan_free_shadow(vm);
1504 free_unmap_vmap_area(va);
1505
1506 return vm;
1507 }
1508 return NULL;
1509}
1510
1511static void __vunmap(const void *addr, int deallocate_pages)
1512{
1513 struct vm_struct *area;
1514
1515 if (!addr)
1516 return;
1517
1518 if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n",
1519 addr))
1520 return;
1521
1522 area = remove_vm_area(addr);
1523 if (unlikely(!area)) {
1524 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
1525 addr);
1526 return;
1527 }
1528
1529 debug_check_no_locks_freed(addr, get_vm_area_size(area));
1530 debug_check_no_obj_freed(addr, get_vm_area_size(area));
1531
1532 if (deallocate_pages) {
1533 int i;
1534
1535 for (i = 0; i < area->nr_pages; i++) {
1536 struct page *page = area->pages[i];
1537
1538 BUG_ON(!page);
1539 __free_pages(page, 0);
1540 }
1541
1542 kvfree(area->pages);
1543 }
1544
1545 kfree(area);
1546 return;
1547}
1548
1549static inline void __vfree_deferred(const void *addr)
1550{
1551 /*
1552 * Use raw_cpu_ptr() because this can be called from preemptible
1553 * context. Preemption is absolutely fine here, because the llist_add()
1554 * implementation is lockless, so it works even if we are adding to
1555 * nother cpu's list. schedule_work() should be fine with this too.
1556 */
1557 struct vfree_deferred *p = raw_cpu_ptr(&vfree_deferred);
1558
1559 if (llist_add((struct llist_node *)addr, &p->list))
1560 schedule_work(&p->wq);
1561}
1562
1563/**
1564 * vfree_atomic - release memory allocated by vmalloc()
1565 * @addr: memory base address
1566 *
1567 * This one is just like vfree() but can be called in any atomic context
1568 * except NMIs.
1569 */
1570void vfree_atomic(const void *addr)
1571{
1572 BUG_ON(in_nmi());
1573
1574 kmemleak_free(addr);
1575
1576 if (!addr)
1577 return;
1578 __vfree_deferred(addr);
1579}
1580
1581/**
1582 * vfree - release memory allocated by vmalloc()
1583 * @addr: memory base address
1584 *
1585 * Free the virtually continuous memory area starting at @addr, as
1586 * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
1587 * NULL, no operation is performed.
1588 *
1589 * Must not be called in NMI context (strictly speaking, only if we don't
1590 * have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling
1591 * conventions for vfree() arch-depenedent would be a really bad idea)
1592 *
1593 * NOTE: assumes that the object at @addr has a size >= sizeof(llist_node)
1594 */
1595void vfree(const void *addr)
1596{
1597 BUG_ON(in_nmi());
1598
1599 kmemleak_free(addr);
1600
1601 if (!addr)
1602 return;
1603 if (unlikely(in_interrupt()))
1604 __vfree_deferred(addr);
1605 else
1606 __vunmap(addr, 1);
1607}
1608EXPORT_SYMBOL(vfree);
1609
1610/**
1611 * vunmap - release virtual mapping obtained by vmap()
1612 * @addr: memory base address
1613 *
1614 * Free the virtually contiguous memory area starting at @addr,
1615 * which was created from the page array passed to vmap().
1616 *
1617 * Must not be called in interrupt context.
1618 */
1619void vunmap(const void *addr)
1620{
1621 BUG_ON(in_interrupt());
1622 might_sleep();
1623 if (addr)
1624 __vunmap(addr, 0);
1625}
1626EXPORT_SYMBOL(vunmap);
1627
1628/**
1629 * vmap - map an array of pages into virtually contiguous space
1630 * @pages: array of page pointers
1631 * @count: number of pages to map
1632 * @flags: vm_area->flags
1633 * @prot: page protection for the mapping
1634 *
1635 * Maps @count pages from @pages into contiguous kernel virtual
1636 * space.
1637 */
1638void *vmap(struct page **pages, unsigned int count,
1639 unsigned long flags, pgprot_t prot)
1640{
1641 struct vm_struct *area;
1642 unsigned long size; /* In bytes */
1643
1644 might_sleep();
1645
1646 if (count > totalram_pages)
1647 return NULL;
1648
1649 size = (unsigned long)count << PAGE_SHIFT;
1650 area = get_vm_area_caller(size, flags, __builtin_return_address(0));
1651 if (!area)
1652 return NULL;
1653
1654 if (map_vm_area(area, prot, pages)) {
1655 vunmap(area->addr);
1656 return NULL;
1657 }
1658
1659 return area->addr;
1660}
1661EXPORT_SYMBOL(vmap);
1662
1663static void *__vmalloc_node(unsigned long size, unsigned long align,
1664 gfp_t gfp_mask, pgprot_t prot,
1665 int node, const void *caller);
1666static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
1667 pgprot_t prot, int node)
1668{
1669 struct page **pages;
1670 unsigned int nr_pages, array_size, i;
1671 const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
1672 const gfp_t alloc_mask = gfp_mask | __GFP_NOWARN;
1673 const gfp_t highmem_mask = (gfp_mask & (GFP_DMA | GFP_DMA32)) ?
1674 0 :
1675 __GFP_HIGHMEM;
1676
1677 nr_pages = get_vm_area_size(area) >> PAGE_SHIFT;
1678 array_size = (nr_pages * sizeof(struct page *));
1679
1680 area->nr_pages = nr_pages;
1681 /* Please note that the recursion is strictly bounded. */
1682 if (array_size > PAGE_SIZE) {
1683 pages = __vmalloc_node(array_size, 1, nested_gfp|highmem_mask,
1684 PAGE_KERNEL, node, area->caller);
1685 } else {
1686 pages = kmalloc_node(array_size, nested_gfp, node);
1687 }
1688 area->pages = pages;
1689 if (!area->pages) {
1690 remove_vm_area(area->addr);
1691 kfree(area);
1692 return NULL;
1693 }
1694
1695 for (i = 0; i < area->nr_pages; i++) {
1696 struct page *page;
1697
1698 if (node == NUMA_NO_NODE)
1699 page = alloc_page(alloc_mask|highmem_mask);
1700 else
1701 page = alloc_pages_node(node, alloc_mask|highmem_mask, 0);
1702
1703 if (unlikely(!page)) {
1704 /* Successfully allocated i pages, free them in __vunmap() */
1705 area->nr_pages = i;
1706 goto fail;
1707 }
1708 area->pages[i] = page;
1709 if (gfpflags_allow_blocking(gfp_mask|highmem_mask))
1710 cond_resched();
1711 }
1712
1713 if (map_vm_area(area, prot, pages))
1714 goto fail;
1715 return area->addr;
1716
1717fail:
1718 warn_alloc(gfp_mask, NULL,
1719 "vmalloc: allocation failure, allocated %ld of %ld bytes",
1720 (area->nr_pages*PAGE_SIZE), area->size);
1721 vfree(area->addr);
1722 return NULL;
1723}
1724
1725/**
1726 * __vmalloc_node_range - allocate virtually contiguous memory
1727 * @size: allocation size
1728 * @align: desired alignment
1729 * @start: vm area range start
1730 * @end: vm area range end
1731 * @gfp_mask: flags for the page level allocator
1732 * @prot: protection mask for the allocated pages
1733 * @vm_flags: additional vm area flags (e.g. %VM_NO_GUARD)
1734 * @node: node to use for allocation or NUMA_NO_NODE
1735 * @caller: caller's return address
1736 *
1737 * Allocate enough pages to cover @size from the page level
1738 * allocator with @gfp_mask flags. Map them into contiguous
1739 * kernel virtual space, using a pagetable protection of @prot.
1740 */
1741void *__vmalloc_node_range(unsigned long size, unsigned long align,
1742 unsigned long start, unsigned long end, gfp_t gfp_mask,
1743 pgprot_t prot, unsigned long vm_flags, int node,
1744 const void *caller)
1745{
1746 struct vm_struct *area;
1747 void *addr;
1748 unsigned long real_size = size;
1749
1750 size = PAGE_ALIGN(size);
1751 if (!size || (size >> PAGE_SHIFT) > totalram_pages)
1752 goto fail;
1753
1754 area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED |
1755 vm_flags, start, end, node, gfp_mask, caller);
1756 if (!area)
1757 goto fail;
1758
1759 addr = __vmalloc_area_node(area, gfp_mask, prot, node);
1760 if (!addr)
1761 return NULL;
1762
1763 /*
1764 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
1765 * flag. It means that vm_struct is not fully initialized.
1766 * Now, it is fully initialized, so remove this flag here.
1767 */
1768 clear_vm_uninitialized_flag(area);
1769
1770 kmemleak_vmalloc(area, size, gfp_mask);
1771
1772 return addr;
1773
1774fail:
1775 warn_alloc(gfp_mask, NULL,
1776 "vmalloc: allocation failure: %lu bytes", real_size);
1777 return NULL;
1778}
1779
1780/**
1781 * __vmalloc_node - allocate virtually contiguous memory
1782 * @size: allocation size
1783 * @align: desired alignment
1784 * @gfp_mask: flags for the page level allocator
1785 * @prot: protection mask for the allocated pages
1786 * @node: node to use for allocation or NUMA_NO_NODE
1787 * @caller: caller's return address
1788 *
1789 * Allocate enough pages to cover @size from the page level
1790 * allocator with @gfp_mask flags. Map them into contiguous
1791 * kernel virtual space, using a pagetable protection of @prot.
1792 *
1793 * Reclaim modifiers in @gfp_mask - __GFP_NORETRY, __GFP_RETRY_MAYFAIL
1794 * and __GFP_NOFAIL are not supported
1795 *
1796 * Any use of gfp flags outside of GFP_KERNEL should be consulted
1797 * with mm people.
1798 *
1799 */
1800static void *__vmalloc_node(unsigned long size, unsigned long align,
1801 gfp_t gfp_mask, pgprot_t prot,
1802 int node, const void *caller)
1803{
1804 return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
1805 gfp_mask, prot, 0, node, caller);
1806}
1807
1808void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
1809{
1810 return __vmalloc_node(size, 1, gfp_mask, prot, NUMA_NO_NODE,
1811 __builtin_return_address(0));
1812}
1813EXPORT_SYMBOL(__vmalloc);
1814
1815static inline void *__vmalloc_node_flags(unsigned long size,
1816 int node, gfp_t flags)
1817{
1818 return __vmalloc_node(size, 1, flags, PAGE_KERNEL,
1819 node, __builtin_return_address(0));
1820}
1821
1822
1823void *__vmalloc_node_flags_caller(unsigned long size, int node, gfp_t flags,
1824 void *caller)
1825{
1826 return __vmalloc_node(size, 1, flags, PAGE_KERNEL, node, caller);
1827}
1828
1829/**
1830 * vmalloc - allocate virtually contiguous memory
1831 * @size: allocation size
1832 * Allocate enough pages to cover @size from the page level
1833 * allocator and map them into contiguous kernel virtual space.
1834 *
1835 * For tight control over page level allocator and protection flags
1836 * use __vmalloc() instead.
1837 */
1838void *vmalloc(unsigned long size)
1839{
1840 return __vmalloc_node_flags(size, NUMA_NO_NODE,
1841 GFP_KERNEL);
1842}
1843EXPORT_SYMBOL(vmalloc);
1844
1845/**
1846 * vzalloc - allocate virtually contiguous memory with zero fill
1847 * @size: allocation size
1848 * Allocate enough pages to cover @size from the page level
1849 * allocator and map them into contiguous kernel virtual space.
1850 * The memory allocated is set to zero.
1851 *
1852 * For tight control over page level allocator and protection flags
1853 * use __vmalloc() instead.
1854 */
1855void *vzalloc(unsigned long size)
1856{
1857 return __vmalloc_node_flags(size, NUMA_NO_NODE,
1858 GFP_KERNEL | __GFP_ZERO);
1859}
1860EXPORT_SYMBOL(vzalloc);
1861
1862/**
1863 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
1864 * @size: allocation size
1865 *
1866 * The resulting memory area is zeroed so it can be mapped to userspace
1867 * without leaking data.
1868 */
1869void *vmalloc_user(unsigned long size)
1870{
1871 struct vm_struct *area;
1872 void *ret;
1873
1874 ret = __vmalloc_node(size, SHMLBA,
1875 GFP_KERNEL | __GFP_ZERO,
1876 PAGE_KERNEL, NUMA_NO_NODE,
1877 __builtin_return_address(0));
1878 if (ret) {
1879 area = find_vm_area(ret);
1880 area->flags |= VM_USERMAP;
1881 }
1882 return ret;
1883}
1884EXPORT_SYMBOL(vmalloc_user);
1885
1886/**
1887 * vmalloc_node - allocate memory on a specific node
1888 * @size: allocation size
1889 * @node: numa node
1890 *
1891 * Allocate enough pages to cover @size from the page level
1892 * allocator and map them into contiguous kernel virtual space.
1893 *
1894 * For tight control over page level allocator and protection flags
1895 * use __vmalloc() instead.
1896 */
1897void *vmalloc_node(unsigned long size, int node)
1898{
1899 return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL,
1900 node, __builtin_return_address(0));
1901}
1902EXPORT_SYMBOL(vmalloc_node);
1903
1904/**
1905 * vzalloc_node - allocate memory on a specific node with zero fill
1906 * @size: allocation size
1907 * @node: numa node
1908 *
1909 * Allocate enough pages to cover @size from the page level
1910 * allocator and map them into contiguous kernel virtual space.
1911 * The memory allocated is set to zero.
1912 *
1913 * For tight control over page level allocator and protection flags
1914 * use __vmalloc_node() instead.
1915 */
1916void *vzalloc_node(unsigned long size, int node)
1917{
1918 return __vmalloc_node_flags(size, node,
1919 GFP_KERNEL | __GFP_ZERO);
1920}
1921EXPORT_SYMBOL(vzalloc_node);
1922
1923#ifndef PAGE_KERNEL_EXEC
1924# define PAGE_KERNEL_EXEC PAGE_KERNEL
1925#endif
1926
1927/**
1928 * vmalloc_exec - allocate virtually contiguous, executable memory
1929 * @size: allocation size
1930 *
1931 * Kernel-internal function to allocate enough pages to cover @size
1932 * the page level allocator and map them into contiguous and
1933 * executable kernel virtual space.
1934 *
1935 * For tight control over page level allocator and protection flags
1936 * use __vmalloc() instead.
1937 */
1938
1939void *vmalloc_exec(unsigned long size)
1940{
1941 return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL_EXEC,
1942 NUMA_NO_NODE, __builtin_return_address(0));
1943}
1944
1945#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
1946#define GFP_VMALLOC32 (GFP_DMA32 | GFP_KERNEL)
1947#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
1948#define GFP_VMALLOC32 (GFP_DMA | GFP_KERNEL)
1949#else
1950/*
1951 * 64b systems should always have either DMA or DMA32 zones. For others
1952 * GFP_DMA32 should do the right thing and use the normal zone.
1953 */
1954#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
1955#endif
1956
1957/**
1958 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
1959 * @size: allocation size
1960 *
1961 * Allocate enough 32bit PA addressable pages to cover @size from the
1962 * page level allocator and map them into contiguous kernel virtual space.
1963 */
1964void *vmalloc_32(unsigned long size)
1965{
1966 return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
1967 NUMA_NO_NODE, __builtin_return_address(0));
1968}
1969EXPORT_SYMBOL(vmalloc_32);
1970
1971/**
1972 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
1973 * @size: allocation size
1974 *
1975 * The resulting memory area is 32bit addressable and zeroed so it can be
1976 * mapped to userspace without leaking data.
1977 */
1978void *vmalloc_32_user(unsigned long size)
1979{
1980 struct vm_struct *area;
1981 void *ret;
1982
1983 ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
1984 NUMA_NO_NODE, __builtin_return_address(0));
1985 if (ret) {
1986 area = find_vm_area(ret);
1987 area->flags |= VM_USERMAP;
1988 }
1989 return ret;
1990}
1991EXPORT_SYMBOL(vmalloc_32_user);
1992
1993/*
1994 * small helper routine , copy contents to buf from addr.
1995 * If the page is not present, fill zero.
1996 */
1997
1998static int aligned_vread(char *buf, char *addr, unsigned long count)
1999{
2000 struct page *p;
2001 int copied = 0;
2002
2003 while (count) {
2004 unsigned long offset, length;
2005
2006 offset = offset_in_page(addr);
2007 length = PAGE_SIZE - offset;
2008 if (length > count)
2009 length = count;
2010 p = vmalloc_to_page(addr);
2011 /*
2012 * To do safe access to this _mapped_ area, we need
2013 * lock. But adding lock here means that we need to add
2014 * overhead of vmalloc()/vfree() calles for this _debug_
2015 * interface, rarely used. Instead of that, we'll use
2016 * kmap() and get small overhead in this access function.
2017 */
2018 if (p) {
2019 /*
2020 * we can expect USER0 is not used (see vread/vwrite's
2021 * function description)
2022 */
2023 void *map = kmap_atomic(p);
2024 memcpy(buf, map + offset, length);
2025 kunmap_atomic(map);
2026 } else
2027 memset(buf, 0, length);
2028
2029 addr += length;
2030 buf += length;
2031 copied += length;
2032 count -= length;
2033 }
2034 return copied;
2035}
2036
2037static int aligned_vwrite(char *buf, char *addr, unsigned long count)
2038{
2039 struct page *p;
2040 int copied = 0;
2041
2042 while (count) {
2043 unsigned long offset, length;
2044
2045 offset = offset_in_page(addr);
2046 length = PAGE_SIZE - offset;
2047 if (length > count)
2048 length = count;
2049 p = vmalloc_to_page(addr);
2050 /*
2051 * To do safe access to this _mapped_ area, we need
2052 * lock. But adding lock here means that we need to add
2053 * overhead of vmalloc()/vfree() calles for this _debug_
2054 * interface, rarely used. Instead of that, we'll use
2055 * kmap() and get small overhead in this access function.
2056 */
2057 if (p) {
2058 /*
2059 * we can expect USER0 is not used (see vread/vwrite's
2060 * function description)
2061 */
2062 void *map = kmap_atomic(p);
2063 memcpy(map + offset, buf, length);
2064 kunmap_atomic(map);
2065 }
2066 addr += length;
2067 buf += length;
2068 copied += length;
2069 count -= length;
2070 }
2071 return copied;
2072}
2073
2074/**
2075 * vread() - read vmalloc area in a safe way.
2076 * @buf: buffer for reading data
2077 * @addr: vm address.
2078 * @count: number of bytes to be read.
2079 *
2080 * Returns # of bytes which addr and buf should be increased.
2081 * (same number to @count). Returns 0 if [addr...addr+count) doesn't
2082 * includes any intersect with alive vmalloc area.
2083 *
2084 * This function checks that addr is a valid vmalloc'ed area, and
2085 * copy data from that area to a given buffer. If the given memory range
2086 * of [addr...addr+count) includes some valid address, data is copied to
2087 * proper area of @buf. If there are memory holes, they'll be zero-filled.
2088 * IOREMAP area is treated as memory hole and no copy is done.
2089 *
2090 * If [addr...addr+count) doesn't includes any intersects with alive
2091 * vm_struct area, returns 0. @buf should be kernel's buffer.
2092 *
2093 * Note: In usual ops, vread() is never necessary because the caller
2094 * should know vmalloc() area is valid and can use memcpy().
2095 * This is for routines which have to access vmalloc area without
2096 * any informaion, as /dev/kmem.
2097 *
2098 */
2099
2100long vread(char *buf, char *addr, unsigned long count)
2101{
2102 struct vmap_area *va;
2103 struct vm_struct *vm;
2104 char *vaddr, *buf_start = buf;
2105 unsigned long buflen = count;
2106 unsigned long n;
2107
2108 /* Don't allow overflow */
2109 if ((unsigned long) addr + count < count)
2110 count = -(unsigned long) addr;
2111
2112 spin_lock(&vmap_area_lock);
2113 list_for_each_entry(va, &vmap_area_list, list) {
2114 if (!count)
2115 break;
2116
2117 if (!(va->flags & VM_VM_AREA))
2118 continue;
2119
2120 vm = va->vm;
2121 vaddr = (char *) vm->addr;
2122 if (addr >= vaddr + get_vm_area_size(vm))
2123 continue;
2124 while (addr < vaddr) {
2125 if (count == 0)
2126 goto finished;
2127 *buf = '\0';
2128 buf++;
2129 addr++;
2130 count--;
2131 }
2132 n = vaddr + get_vm_area_size(vm) - addr;
2133 if (n > count)
2134 n = count;
2135 if (!(vm->flags & VM_IOREMAP))
2136 aligned_vread(buf, addr, n);
2137 else /* IOREMAP area is treated as memory hole */
2138 memset(buf, 0, n);
2139 buf += n;
2140 addr += n;
2141 count -= n;
2142 }
2143finished:
2144 spin_unlock(&vmap_area_lock);
2145
2146 if (buf == buf_start)
2147 return 0;
2148 /* zero-fill memory holes */
2149 if (buf != buf_start + buflen)
2150 memset(buf, 0, buflen - (buf - buf_start));
2151
2152 return buflen;
2153}
2154
2155/**
2156 * vwrite() - write vmalloc area in a safe way.
2157 * @buf: buffer for source data
2158 * @addr: vm address.
2159 * @count: number of bytes to be read.
2160 *
2161 * Returns # of bytes which addr and buf should be incresed.
2162 * (same number to @count).
2163 * If [addr...addr+count) doesn't includes any intersect with valid
2164 * vmalloc area, returns 0.
2165 *
2166 * This function checks that addr is a valid vmalloc'ed area, and
2167 * copy data from a buffer to the given addr. If specified range of
2168 * [addr...addr+count) includes some valid address, data is copied from
2169 * proper area of @buf. If there are memory holes, no copy to hole.
2170 * IOREMAP area is treated as memory hole and no copy is done.
2171 *
2172 * If [addr...addr+count) doesn't includes any intersects with alive
2173 * vm_struct area, returns 0. @buf should be kernel's buffer.
2174 *
2175 * Note: In usual ops, vwrite() is never necessary because the caller
2176 * should know vmalloc() area is valid and can use memcpy().
2177 * This is for routines which have to access vmalloc area without
2178 * any informaion, as /dev/kmem.
2179 */
2180
2181long vwrite(char *buf, char *addr, unsigned long count)
2182{
2183 struct vmap_area *va;
2184 struct vm_struct *vm;
2185 char *vaddr;
2186 unsigned long n, buflen;
2187 int copied = 0;
2188
2189 /* Don't allow overflow */
2190 if ((unsigned long) addr + count < count)
2191 count = -(unsigned long) addr;
2192 buflen = count;
2193
2194 spin_lock(&vmap_area_lock);
2195 list_for_each_entry(va, &vmap_area_list, list) {
2196 if (!count)
2197 break;
2198
2199 if (!(va->flags & VM_VM_AREA))
2200 continue;
2201
2202 vm = va->vm;
2203 vaddr = (char *) vm->addr;
2204 if (addr >= vaddr + get_vm_area_size(vm))
2205 continue;
2206 while (addr < vaddr) {
2207 if (count == 0)
2208 goto finished;
2209 buf++;
2210 addr++;
2211 count--;
2212 }
2213 n = vaddr + get_vm_area_size(vm) - addr;
2214 if (n > count)
2215 n = count;
2216 if (!(vm->flags & VM_IOREMAP)) {
2217 aligned_vwrite(buf, addr, n);
2218 copied++;
2219 }
2220 buf += n;
2221 addr += n;
2222 count -= n;
2223 }
2224finished:
2225 spin_unlock(&vmap_area_lock);
2226 if (!copied)
2227 return 0;
2228 return buflen;
2229}
2230
2231/**
2232 * remap_vmalloc_range_partial - map vmalloc pages to userspace
2233 * @vma: vma to cover
2234 * @uaddr: target user address to start at
2235 * @kaddr: virtual address of vmalloc kernel memory
2236 * @size: size of map area
2237 *
2238 * Returns: 0 for success, -Exxx on failure
2239 *
2240 * This function checks that @kaddr is a valid vmalloc'ed area,
2241 * and that it is big enough to cover the range starting at
2242 * @uaddr in @vma. Will return failure if that criteria isn't
2243 * met.
2244 *
2245 * Similar to remap_pfn_range() (see mm/memory.c)
2246 */
2247int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
2248 void *kaddr, unsigned long size)
2249{
2250 struct vm_struct *area;
2251
2252 size = PAGE_ALIGN(size);
2253
2254 if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr))
2255 return -EINVAL;
2256
2257 area = find_vm_area(kaddr);
2258 if (!area)
2259 return -EINVAL;
2260
2261 if (!(area->flags & VM_USERMAP))
2262 return -EINVAL;
2263
2264 if (kaddr + size > area->addr + area->size)
2265 return -EINVAL;
2266
2267 do {
2268 struct page *page = vmalloc_to_page(kaddr);
2269 int ret;
2270
2271 ret = vm_insert_page(vma, uaddr, page);
2272 if (ret)
2273 return ret;
2274
2275 uaddr += PAGE_SIZE;
2276 kaddr += PAGE_SIZE;
2277 size -= PAGE_SIZE;
2278 } while (size > 0);
2279
2280 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
2281
2282 return 0;
2283}
2284EXPORT_SYMBOL(remap_vmalloc_range_partial);
2285
2286/**
2287 * remap_vmalloc_range - map vmalloc pages to userspace
2288 * @vma: vma to cover (map full range of vma)
2289 * @addr: vmalloc memory
2290 * @pgoff: number of pages into addr before first page to map
2291 *
2292 * Returns: 0 for success, -Exxx on failure
2293 *
2294 * This function checks that addr is a valid vmalloc'ed area, and
2295 * that it is big enough to cover the vma. Will return failure if
2296 * that criteria isn't met.
2297 *
2298 * Similar to remap_pfn_range() (see mm/memory.c)
2299 */
2300int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
2301 unsigned long pgoff)
2302{
2303 return remap_vmalloc_range_partial(vma, vma->vm_start,
2304 addr + (pgoff << PAGE_SHIFT),
2305 vma->vm_end - vma->vm_start);
2306}
2307EXPORT_SYMBOL(remap_vmalloc_range);
2308
2309/*
2310 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
2311 * have one.
2312 */
2313void __weak vmalloc_sync_all(void)
2314{
2315}
2316
2317
2318static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
2319{
2320 pte_t ***p = data;
2321
2322 if (p) {
2323 *(*p) = pte;
2324 (*p)++;
2325 }
2326 return 0;
2327}
2328
2329/**
2330 * alloc_vm_area - allocate a range of kernel address space
2331 * @size: size of the area
2332 * @ptes: returns the PTEs for the address space
2333 *
2334 * Returns: NULL on failure, vm_struct on success
2335 *
2336 * This function reserves a range of kernel address space, and
2337 * allocates pagetables to map that range. No actual mappings
2338 * are created.
2339 *
2340 * If @ptes is non-NULL, pointers to the PTEs (in init_mm)
2341 * allocated for the VM area are returned.
2342 */
2343struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
2344{
2345 struct vm_struct *area;
2346
2347 area = get_vm_area_caller(size, VM_IOREMAP,
2348 __builtin_return_address(0));
2349 if (area == NULL)
2350 return NULL;
2351
2352 /*
2353 * This ensures that page tables are constructed for this region
2354 * of kernel virtual address space and mapped into init_mm.
2355 */
2356 if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
2357 size, f, ptes ? &ptes : NULL)) {
2358 free_vm_area(area);
2359 return NULL;
2360 }
2361
2362 return area;
2363}
2364EXPORT_SYMBOL_GPL(alloc_vm_area);
2365
2366void free_vm_area(struct vm_struct *area)
2367{
2368 struct vm_struct *ret;
2369 ret = remove_vm_area(area->addr);
2370 BUG_ON(ret != area);
2371 kfree(area);
2372}
2373EXPORT_SYMBOL_GPL(free_vm_area);
2374
2375#ifdef CONFIG_SMP
2376static struct vmap_area *node_to_va(struct rb_node *n)
2377{
2378 return rb_entry_safe(n, struct vmap_area, rb_node);
2379}
2380
2381/**
2382 * pvm_find_next_prev - find the next and prev vmap_area surrounding @end
2383 * @end: target address
2384 * @pnext: out arg for the next vmap_area
2385 * @pprev: out arg for the previous vmap_area
2386 *
2387 * Returns: %true if either or both of next and prev are found,
2388 * %false if no vmap_area exists
2389 *
2390 * Find vmap_areas end addresses of which enclose @end. ie. if not
2391 * NULL, *pnext->va_end > @end and *pprev->va_end <= @end.
2392 */
2393static bool pvm_find_next_prev(unsigned long end,
2394 struct vmap_area **pnext,
2395 struct vmap_area **pprev)
2396{
2397 struct rb_node *n = vmap_area_root.rb_node;
2398 struct vmap_area *va = NULL;
2399
2400 while (n) {
2401 va = rb_entry(n, struct vmap_area, rb_node);
2402 if (end < va->va_end)
2403 n = n->rb_left;
2404 else if (end > va->va_end)
2405 n = n->rb_right;
2406 else
2407 break;
2408 }
2409
2410 if (!va)
2411 return false;
2412
2413 if (va->va_end > end) {
2414 *pnext = va;
2415 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2416 } else {
2417 *pprev = va;
2418 *pnext = node_to_va(rb_next(&(*pprev)->rb_node));
2419 }
2420 return true;
2421}
2422
2423/**
2424 * pvm_determine_end - find the highest aligned address between two vmap_areas
2425 * @pnext: in/out arg for the next vmap_area
2426 * @pprev: in/out arg for the previous vmap_area
2427 * @align: alignment
2428 *
2429 * Returns: determined end address
2430 *
2431 * Find the highest aligned address between *@pnext and *@pprev below
2432 * VMALLOC_END. *@pnext and *@pprev are adjusted so that the aligned
2433 * down address is between the end addresses of the two vmap_areas.
2434 *
2435 * Please note that the address returned by this function may fall
2436 * inside *@pnext vmap_area. The caller is responsible for checking
2437 * that.
2438 */
2439static unsigned long pvm_determine_end(struct vmap_area **pnext,
2440 struct vmap_area **pprev,
2441 unsigned long align)
2442{
2443 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2444 unsigned long addr;
2445
2446 if (*pnext)
2447 addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end);
2448 else
2449 addr = vmalloc_end;
2450
2451 while (*pprev && (*pprev)->va_end > addr) {
2452 *pnext = *pprev;
2453 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
2454 }
2455
2456 return addr;
2457}
2458
2459/**
2460 * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
2461 * @offsets: array containing offset of each area
2462 * @sizes: array containing size of each area
2463 * @nr_vms: the number of areas to allocate
2464 * @align: alignment, all entries in @offsets and @sizes must be aligned to this
2465 *
2466 * Returns: kmalloc'd vm_struct pointer array pointing to allocated
2467 * vm_structs on success, %NULL on failure
2468 *
2469 * Percpu allocator wants to use congruent vm areas so that it can
2470 * maintain the offsets among percpu areas. This function allocates
2471 * congruent vmalloc areas for it with GFP_KERNEL. These areas tend to
2472 * be scattered pretty far, distance between two areas easily going up
2473 * to gigabytes. To avoid interacting with regular vmallocs, these
2474 * areas are allocated from top.
2475 *
2476 * Despite its complicated look, this allocator is rather simple. It
2477 * does everything top-down and scans areas from the end looking for
2478 * matching slot. While scanning, if any of the areas overlaps with
2479 * existing vmap_area, the base address is pulled down to fit the
2480 * area. Scanning is repeated till all the areas fit and then all
2481 * necessary data structures are inserted and the result is returned.
2482 */
2483struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
2484 const size_t *sizes, int nr_vms,
2485 size_t align)
2486{
2487 const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
2488 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
2489 struct vmap_area **vas, *prev, *next;
2490 struct vm_struct **vms;
2491 int area, area2, last_area, term_area;
2492 unsigned long base, start, end, last_end;
2493 bool purged = false;
2494
2495 /* verify parameters and allocate data structures */
2496 BUG_ON(offset_in_page(align) || !is_power_of_2(align));
2497 for (last_area = 0, area = 0; area < nr_vms; area++) {
2498 start = offsets[area];
2499 end = start + sizes[area];
2500
2501 /* is everything aligned properly? */
2502 BUG_ON(!IS_ALIGNED(offsets[area], align));
2503 BUG_ON(!IS_ALIGNED(sizes[area], align));
2504
2505 /* detect the area with the highest address */
2506 if (start > offsets[last_area])
2507 last_area = area;
2508
2509 for (area2 = area + 1; area2 < nr_vms; area2++) {
2510 unsigned long start2 = offsets[area2];
2511 unsigned long end2 = start2 + sizes[area2];
2512
2513 BUG_ON(start2 < end && start < end2);
2514 }
2515 }
2516 last_end = offsets[last_area] + sizes[last_area];
2517
2518 if (vmalloc_end - vmalloc_start < last_end) {
2519 WARN_ON(true);
2520 return NULL;
2521 }
2522
2523 vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL);
2524 vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL);
2525 if (!vas || !vms)
2526 goto err_free2;
2527
2528 for (area = 0; area < nr_vms; area++) {
2529 vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL);
2530 vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL);
2531 if (!vas[area] || !vms[area])
2532 goto err_free;
2533 }
2534retry:
2535 spin_lock(&vmap_area_lock);
2536
2537 /* start scanning - we scan from the top, begin with the last area */
2538 area = term_area = last_area;
2539 start = offsets[area];
2540 end = start + sizes[area];
2541
2542 if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) {
2543 base = vmalloc_end - last_end;
2544 goto found;
2545 }
2546 base = pvm_determine_end(&next, &prev, align) - end;
2547
2548 while (true) {
2549 BUG_ON(next && next->va_end <= base + end);
2550 BUG_ON(prev && prev->va_end > base + end);
2551
2552 /*
2553 * base might have underflowed, add last_end before
2554 * comparing.
2555 */
2556 if (base + last_end < vmalloc_start + last_end) {
2557 spin_unlock(&vmap_area_lock);
2558 if (!purged) {
2559 purge_vmap_area_lazy();
2560 purged = true;
2561 goto retry;
2562 }
2563 goto err_free;
2564 }
2565
2566 /*
2567 * If next overlaps, move base downwards so that it's
2568 * right below next and then recheck.
2569 */
2570 if (next && next->va_start < base + end) {
2571 base = pvm_determine_end(&next, &prev, align) - end;
2572 term_area = area;
2573 continue;
2574 }
2575
2576 /*
2577 * If prev overlaps, shift down next and prev and move
2578 * base so that it's right below new next and then
2579 * recheck.
2580 */
2581 if (prev && prev->va_end > base + start) {
2582 next = prev;
2583 prev = node_to_va(rb_prev(&next->rb_node));
2584 base = pvm_determine_end(&next, &prev, align) - end;
2585 term_area = area;
2586 continue;
2587 }
2588
2589 /*
2590 * This area fits, move on to the previous one. If
2591 * the previous one is the terminal one, we're done.
2592 */
2593 area = (area + nr_vms - 1) % nr_vms;
2594 if (area == term_area)
2595 break;
2596 start = offsets[area];
2597 end = start + sizes[area];
2598 pvm_find_next_prev(base + end, &next, &prev);
2599 }
2600found:
2601 /* we've found a fitting base, insert all va's */
2602 for (area = 0; area < nr_vms; area++) {
2603 struct vmap_area *va = vas[area];
2604
2605 va->va_start = base + offsets[area];
2606 va->va_end = va->va_start + sizes[area];
2607 __insert_vmap_area(va);
2608 }
2609
2610 vmap_area_pcpu_hole = base + offsets[last_area];
2611
2612 spin_unlock(&vmap_area_lock);
2613
2614 /* insert all vm's */
2615 for (area = 0; area < nr_vms; area++)
2616 setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC,
2617 pcpu_get_vm_areas);
2618
2619 kfree(vas);
2620 return vms;
2621
2622err_free:
2623 for (area = 0; area < nr_vms; area++) {
2624 kfree(vas[area]);
2625 kfree(vms[area]);
2626 }
2627err_free2:
2628 kfree(vas);
2629 kfree(vms);
2630 return NULL;
2631}
2632
2633/**
2634 * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
2635 * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
2636 * @nr_vms: the number of allocated areas
2637 *
2638 * Free vm_structs and the array allocated by pcpu_get_vm_areas().
2639 */
2640void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
2641{
2642 int i;
2643
2644 for (i = 0; i < nr_vms; i++)
2645 free_vm_area(vms[i]);
2646 kfree(vms);
2647}
2648#endif /* CONFIG_SMP */
2649
2650#ifdef CONFIG_PROC_FS
2651static void *s_start(struct seq_file *m, loff_t *pos)
2652 __acquires(&vmap_area_lock)
2653{
2654 spin_lock(&vmap_area_lock);
2655 return seq_list_start(&vmap_area_list, *pos);
2656}
2657
2658static void *s_next(struct seq_file *m, void *p, loff_t *pos)
2659{
2660 return seq_list_next(p, &vmap_area_list, pos);
2661}
2662
2663static void s_stop(struct seq_file *m, void *p)
2664 __releases(&vmap_area_lock)
2665{
2666 spin_unlock(&vmap_area_lock);
2667}
2668
2669static void show_numa_info(struct seq_file *m, struct vm_struct *v)
2670{
2671 if (IS_ENABLED(CONFIG_NUMA)) {
2672 unsigned int nr, *counters = m->private;
2673
2674 if (!counters)
2675 return;
2676
2677 if (v->flags & VM_UNINITIALIZED)
2678 return;
2679 /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
2680 smp_rmb();
2681
2682 memset(counters, 0, nr_node_ids * sizeof(unsigned int));
2683
2684 for (nr = 0; nr < v->nr_pages; nr++)
2685 counters[page_to_nid(v->pages[nr])]++;
2686
2687 for_each_node_state(nr, N_HIGH_MEMORY)
2688 if (counters[nr])
2689 seq_printf(m, " N%u=%u", nr, counters[nr]);
2690 }
2691}
2692
2693static int s_show(struct seq_file *m, void *p)
2694{
2695 struct vmap_area *va;
2696 struct vm_struct *v;
2697
2698 va = list_entry(p, struct vmap_area, list);
2699
2700 /*
2701 * s_show can encounter race with remove_vm_area, !VM_VM_AREA on
2702 * behalf of vmap area is being tear down or vm_map_ram allocation.
2703 */
2704 if (!(va->flags & VM_VM_AREA)) {
2705 seq_printf(m, "0x%pK-0x%pK %7ld %s\n",
2706 (void *)va->va_start, (void *)va->va_end,
2707 va->va_end - va->va_start,
2708 va->flags & VM_LAZY_FREE ? "unpurged vm_area" : "vm_map_ram");
2709
2710 return 0;
2711 }
2712
2713 v = va->vm;
2714
2715 seq_printf(m, "0x%pK-0x%pK %7ld",
2716 v->addr, v->addr + v->size, v->size);
2717
2718 if (v->caller)
2719 seq_printf(m, " %pS", v->caller);
2720
2721 if (v->nr_pages)
2722 seq_printf(m, " pages=%d", v->nr_pages);
2723
2724 if (v->phys_addr)
2725 seq_printf(m, " phys=%pa", &v->phys_addr);
2726
2727 if (v->flags & VM_IOREMAP)
2728 seq_puts(m, " ioremap");
2729
2730 if (v->flags & VM_ALLOC)
2731 seq_puts(m, " vmalloc");
2732
2733 if (v->flags & VM_MAP)
2734 seq_puts(m, " vmap");
2735
2736 if (v->flags & VM_USERMAP)
2737 seq_puts(m, " user");
2738
2739 if (is_vmalloc_addr(v->pages))
2740 seq_puts(m, " vpages");
2741
2742 show_numa_info(m, v);
2743 seq_putc(m, '\n');
2744 return 0;
2745}
2746
2747static const struct seq_operations vmalloc_op = {
2748 .start = s_start,
2749 .next = s_next,
2750 .stop = s_stop,
2751 .show = s_show,
2752};
2753
2754static int vmalloc_open(struct inode *inode, struct file *file)
2755{
2756 if (IS_ENABLED(CONFIG_NUMA))
2757 return seq_open_private(file, &vmalloc_op,
2758 nr_node_ids * sizeof(unsigned int));
2759 else
2760 return seq_open(file, &vmalloc_op);
2761}
2762
2763static const struct file_operations proc_vmalloc_operations = {
2764 .open = vmalloc_open,
2765 .read = seq_read,
2766 .llseek = seq_lseek,
2767 .release = seq_release_private,
2768};
2769
2770static int __init proc_vmalloc_init(void)
2771{
2772 proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations);
2773 return 0;
2774}
2775module_init(proc_vmalloc_init);
2776
2777#endif
2778