1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 1993 Linus Torvalds
4 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
5 * SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
6 * Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
7 * Numa awareness, Christoph Lameter, SGI, June 2005
8 * Improving global KVA allocator, Uladzislau Rezki, Sony, May 2019
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/set_memory.h>
22 #include <linux/debugobjects.h>
23 #include <linux/kallsyms.h>
24 #include <linux/list.h>
25 #include <linux/notifier.h>
26 #include <linux/rbtree.h>
27 #include <linux/xarray.h>
28 #include <linux/io.h>
29 #include <linux/rcupdate.h>
30 #include <linux/pfn.h>
31 #include <linux/kmemleak.h>
32 #include <linux/atomic.h>
33 #include <linux/compiler.h>
34 #include <linux/memcontrol.h>
35 #include <linux/llist.h>
36 #include <linux/bitops.h>
37 #include <linux/rbtree_augmented.h>
38 #include <linux/overflow.h>
39 #include <linux/pgtable.h>
40 #include <linux/uaccess.h>
41 #include <linux/hugetlb.h>
42 #include <linux/sched/mm.h>
43 #include <asm/tlbflush.h>
44 #include <asm/shmparam.h>
45
46 #include "internal.h"
47 #include "pgalloc-track.h"
48
49 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
50 static unsigned int __ro_after_init ioremap_max_page_shift = BITS_PER_LONG - 1;
51
set_nohugeiomap(char * str)52 static int __init set_nohugeiomap(char *str)
53 {
54 ioremap_max_page_shift = PAGE_SHIFT;
55 return 0;
56 }
57 early_param("nohugeiomap", set_nohugeiomap);
58 #else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
59 static const unsigned int ioremap_max_page_shift = PAGE_SHIFT;
60 #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
61
62 #ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
63 static bool __ro_after_init vmap_allow_huge = true;
64
set_nohugevmalloc(char * str)65 static int __init set_nohugevmalloc(char *str)
66 {
67 vmap_allow_huge = false;
68 return 0;
69 }
70 early_param("nohugevmalloc", set_nohugevmalloc);
71 #else /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */
72 static const bool vmap_allow_huge = false;
73 #endif /* CONFIG_HAVE_ARCH_HUGE_VMALLOC */
74
is_vmalloc_addr(const void * x)75 bool is_vmalloc_addr(const void *x)
76 {
77 unsigned long addr = (unsigned long)kasan_reset_tag(x);
78
79 return addr >= VMALLOC_START && addr < VMALLOC_END;
80 }
81 EXPORT_SYMBOL(is_vmalloc_addr);
82
83 struct vfree_deferred {
84 struct llist_head list;
85 struct work_struct wq;
86 };
87 static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred);
88
89 static void __vunmap(const void *, int);
90
free_work(struct work_struct * w)91 static void free_work(struct work_struct *w)
92 {
93 struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq);
94 struct llist_node *t, *llnode;
95
96 llist_for_each_safe(llnode, t, llist_del_all(&p->list))
97 __vunmap((void *)llnode, 1);
98 }
99
100 /*** Page table manipulation functions ***/
vmap_pte_range(pmd_t * pmd,unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift,pgtbl_mod_mask * mask)101 static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
102 phys_addr_t phys_addr, pgprot_t prot,
103 unsigned int max_page_shift, pgtbl_mod_mask *mask)
104 {
105 pte_t *pte;
106 u64 pfn;
107 unsigned long size = PAGE_SIZE;
108
109 pfn = phys_addr >> PAGE_SHIFT;
110 pte = pte_alloc_kernel_track(pmd, addr, mask);
111 if (!pte)
112 return -ENOMEM;
113 do {
114 BUG_ON(!pte_none(*pte));
115
116 #ifdef CONFIG_HUGETLB_PAGE
117 size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
118 if (size != PAGE_SIZE) {
119 pte_t entry = pfn_pte(pfn, prot);
120
121 entry = arch_make_huge_pte(entry, ilog2(size), 0);
122 set_huge_pte_at(&init_mm, addr, pte, entry);
123 pfn += PFN_DOWN(size);
124 continue;
125 }
126 #endif
127 set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
128 pfn++;
129 } while (pte += PFN_DOWN(size), addr += size, addr != end);
130 *mask |= PGTBL_PTE_MODIFIED;
131 return 0;
132 }
133
vmap_try_huge_pmd(pmd_t * pmd,unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift)134 static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
135 phys_addr_t phys_addr, pgprot_t prot,
136 unsigned int max_page_shift)
137 {
138 if (max_page_shift < PMD_SHIFT)
139 return 0;
140
141 if (!arch_vmap_pmd_supported(prot))
142 return 0;
143
144 if ((end - addr) != PMD_SIZE)
145 return 0;
146
147 if (!IS_ALIGNED(addr, PMD_SIZE))
148 return 0;
149
150 if (!IS_ALIGNED(phys_addr, PMD_SIZE))
151 return 0;
152
153 if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
154 return 0;
155
156 return pmd_set_huge(pmd, phys_addr, prot);
157 }
158
vmap_pmd_range(pud_t * pud,unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift,pgtbl_mod_mask * mask)159 static int vmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
160 phys_addr_t phys_addr, pgprot_t prot,
161 unsigned int max_page_shift, pgtbl_mod_mask *mask)
162 {
163 pmd_t *pmd;
164 unsigned long next;
165
166 pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
167 if (!pmd)
168 return -ENOMEM;
169 do {
170 next = pmd_addr_end(addr, end);
171
172 if (vmap_try_huge_pmd(pmd, addr, next, phys_addr, prot,
173 max_page_shift)) {
174 *mask |= PGTBL_PMD_MODIFIED;
175 continue;
176 }
177
178 if (vmap_pte_range(pmd, addr, next, phys_addr, prot, max_page_shift, mask))
179 return -ENOMEM;
180 } while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
181 return 0;
182 }
183
vmap_try_huge_pud(pud_t * pud,unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift)184 static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
185 phys_addr_t phys_addr, pgprot_t prot,
186 unsigned int max_page_shift)
187 {
188 if (max_page_shift < PUD_SHIFT)
189 return 0;
190
191 if (!arch_vmap_pud_supported(prot))
192 return 0;
193
194 if ((end - addr) != PUD_SIZE)
195 return 0;
196
197 if (!IS_ALIGNED(addr, PUD_SIZE))
198 return 0;
199
200 if (!IS_ALIGNED(phys_addr, PUD_SIZE))
201 return 0;
202
203 if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
204 return 0;
205
206 return pud_set_huge(pud, phys_addr, prot);
207 }
208
vmap_pud_range(p4d_t * p4d,unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift,pgtbl_mod_mask * mask)209 static int vmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
210 phys_addr_t phys_addr, pgprot_t prot,
211 unsigned int max_page_shift, pgtbl_mod_mask *mask)
212 {
213 pud_t *pud;
214 unsigned long next;
215
216 pud = pud_alloc_track(&init_mm, p4d, addr, mask);
217 if (!pud)
218 return -ENOMEM;
219 do {
220 next = pud_addr_end(addr, end);
221
222 if (vmap_try_huge_pud(pud, addr, next, phys_addr, prot,
223 max_page_shift)) {
224 *mask |= PGTBL_PUD_MODIFIED;
225 continue;
226 }
227
228 if (vmap_pmd_range(pud, addr, next, phys_addr, prot,
229 max_page_shift, mask))
230 return -ENOMEM;
231 } while (pud++, phys_addr += (next - addr), addr = next, addr != end);
232 return 0;
233 }
234
vmap_try_huge_p4d(p4d_t * p4d,unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift)235 static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
236 phys_addr_t phys_addr, pgprot_t prot,
237 unsigned int max_page_shift)
238 {
239 if (max_page_shift < P4D_SHIFT)
240 return 0;
241
242 if (!arch_vmap_p4d_supported(prot))
243 return 0;
244
245 if ((end - addr) != P4D_SIZE)
246 return 0;
247
248 if (!IS_ALIGNED(addr, P4D_SIZE))
249 return 0;
250
251 if (!IS_ALIGNED(phys_addr, P4D_SIZE))
252 return 0;
253
254 if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
255 return 0;
256
257 return p4d_set_huge(p4d, phys_addr, prot);
258 }
259
vmap_p4d_range(pgd_t * pgd,unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift,pgtbl_mod_mask * mask)260 static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
261 phys_addr_t phys_addr, pgprot_t prot,
262 unsigned int max_page_shift, pgtbl_mod_mask *mask)
263 {
264 p4d_t *p4d;
265 unsigned long next;
266
267 p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
268 if (!p4d)
269 return -ENOMEM;
270 do {
271 next = p4d_addr_end(addr, end);
272
273 if (vmap_try_huge_p4d(p4d, addr, next, phys_addr, prot,
274 max_page_shift)) {
275 *mask |= PGTBL_P4D_MODIFIED;
276 continue;
277 }
278
279 if (vmap_pud_range(p4d, addr, next, phys_addr, prot,
280 max_page_shift, mask))
281 return -ENOMEM;
282 } while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
283 return 0;
284 }
285
vmap_range_noflush(unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot,unsigned int max_page_shift)286 static int vmap_range_noflush(unsigned long addr, unsigned long end,
287 phys_addr_t phys_addr, pgprot_t prot,
288 unsigned int max_page_shift)
289 {
290 pgd_t *pgd;
291 unsigned long start;
292 unsigned long next;
293 int err;
294 pgtbl_mod_mask mask = 0;
295
296 might_sleep();
297 BUG_ON(addr >= end);
298
299 start = addr;
300 pgd = pgd_offset_k(addr);
301 do {
302 next = pgd_addr_end(addr, end);
303 err = vmap_p4d_range(pgd, addr, next, phys_addr, prot,
304 max_page_shift, &mask);
305 if (err)
306 break;
307 } while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
308
309 if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
310 arch_sync_kernel_mappings(start, end);
311
312 return err;
313 }
314
ioremap_page_range(unsigned long addr,unsigned long end,phys_addr_t phys_addr,pgprot_t prot)315 int ioremap_page_range(unsigned long addr, unsigned long end,
316 phys_addr_t phys_addr, pgprot_t prot)
317 {
318 int err;
319
320 err = vmap_range_noflush(addr, end, phys_addr, pgprot_nx(prot),
321 ioremap_max_page_shift);
322 flush_cache_vmap(addr, end);
323 if (!err)
324 kmsan_ioremap_page_range(addr, end, phys_addr, prot,
325 ioremap_max_page_shift);
326 return err;
327 }
328
vunmap_pte_range(pmd_t * pmd,unsigned long addr,unsigned long end,pgtbl_mod_mask * mask)329 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
330 pgtbl_mod_mask *mask)
331 {
332 pte_t *pte;
333
334 pte = pte_offset_kernel(pmd, addr);
335 do {
336 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
337 WARN_ON(!pte_none(ptent) && !pte_present(ptent));
338 } while (pte++, addr += PAGE_SIZE, addr != end);
339 *mask |= PGTBL_PTE_MODIFIED;
340 }
341
vunmap_pmd_range(pud_t * pud,unsigned long addr,unsigned long end,pgtbl_mod_mask * mask)342 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
343 pgtbl_mod_mask *mask)
344 {
345 pmd_t *pmd;
346 unsigned long next;
347 int cleared;
348
349 pmd = pmd_offset(pud, addr);
350 do {
351 next = pmd_addr_end(addr, end);
352
353 cleared = pmd_clear_huge(pmd);
354 if (cleared || pmd_bad(*pmd))
355 *mask |= PGTBL_PMD_MODIFIED;
356
357 if (cleared)
358 continue;
359 if (pmd_none_or_clear_bad(pmd))
360 continue;
361 vunmap_pte_range(pmd, addr, next, mask);
362
363 cond_resched();
364 } while (pmd++, addr = next, addr != end);
365 }
366
vunmap_pud_range(p4d_t * p4d,unsigned long addr,unsigned long end,pgtbl_mod_mask * mask)367 static void vunmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
368 pgtbl_mod_mask *mask)
369 {
370 pud_t *pud;
371 unsigned long next;
372 int cleared;
373
374 pud = pud_offset(p4d, addr);
375 do {
376 next = pud_addr_end(addr, end);
377
378 cleared = pud_clear_huge(pud);
379 if (cleared || pud_bad(*pud))
380 *mask |= PGTBL_PUD_MODIFIED;
381
382 if (cleared)
383 continue;
384 if (pud_none_or_clear_bad(pud))
385 continue;
386 vunmap_pmd_range(pud, addr, next, mask);
387 } while (pud++, addr = next, addr != end);
388 }
389
vunmap_p4d_range(pgd_t * pgd,unsigned long addr,unsigned long end,pgtbl_mod_mask * mask)390 static void vunmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
391 pgtbl_mod_mask *mask)
392 {
393 p4d_t *p4d;
394 unsigned long next;
395
396 p4d = p4d_offset(pgd, addr);
397 do {
398 next = p4d_addr_end(addr, end);
399
400 p4d_clear_huge(p4d);
401 if (p4d_bad(*p4d))
402 *mask |= PGTBL_P4D_MODIFIED;
403
404 if (p4d_none_or_clear_bad(p4d))
405 continue;
406 vunmap_pud_range(p4d, addr, next, mask);
407 } while (p4d++, addr = next, addr != end);
408 }
409
410 /*
411 * vunmap_range_noflush is similar to vunmap_range, but does not
412 * flush caches or TLBs.
413 *
414 * The caller is responsible for calling flush_cache_vmap() before calling
415 * this function, and flush_tlb_kernel_range after it has returned
416 * successfully (and before the addresses are expected to cause a page fault
417 * or be re-mapped for something else, if TLB flushes are being delayed or
418 * coalesced).
419 *
420 * This is an internal function only. Do not use outside mm/.
421 */
__vunmap_range_noflush(unsigned long start,unsigned long end)422 void __vunmap_range_noflush(unsigned long start, unsigned long end)
423 {
424 unsigned long next;
425 pgd_t *pgd;
426 unsigned long addr = start;
427 pgtbl_mod_mask mask = 0;
428
429 BUG_ON(addr >= end);
430 pgd = pgd_offset_k(addr);
431 do {
432 next = pgd_addr_end(addr, end);
433 if (pgd_bad(*pgd))
434 mask |= PGTBL_PGD_MODIFIED;
435 if (pgd_none_or_clear_bad(pgd))
436 continue;
437 vunmap_p4d_range(pgd, addr, next, &mask);
438 } while (pgd++, addr = next, addr != end);
439
440 if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
441 arch_sync_kernel_mappings(start, end);
442 }
443
vunmap_range_noflush(unsigned long start,unsigned long end)444 void vunmap_range_noflush(unsigned long start, unsigned long end)
445 {
446 kmsan_vunmap_range_noflush(start, end);
447 __vunmap_range_noflush(start, end);
448 }
449
450 /**
451 * vunmap_range - unmap kernel virtual addresses
452 * @addr: start of the VM area to unmap
453 * @end: end of the VM area to unmap (non-inclusive)
454 *
455 * Clears any present PTEs in the virtual address range, flushes TLBs and
456 * caches. Any subsequent access to the address before it has been re-mapped
457 * is a kernel bug.
458 */
vunmap_range(unsigned long addr,unsigned long end)459 void vunmap_range(unsigned long addr, unsigned long end)
460 {
461 flush_cache_vunmap(addr, end);
462 vunmap_range_noflush(addr, end);
463 flush_tlb_kernel_range(addr, end);
464 }
465
vmap_pages_pte_range(pmd_t * pmd,unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages,int * nr,pgtbl_mod_mask * mask)466 static int vmap_pages_pte_range(pmd_t *pmd, unsigned long addr,
467 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
468 pgtbl_mod_mask *mask)
469 {
470 pte_t *pte;
471
472 /*
473 * nr is a running index into the array which helps higher level
474 * callers keep track of where we're up to.
475 */
476
477 pte = pte_alloc_kernel_track(pmd, addr, mask);
478 if (!pte)
479 return -ENOMEM;
480 do {
481 struct page *page = pages[*nr];
482
483 if (WARN_ON(!pte_none(*pte)))
484 return -EBUSY;
485 if (WARN_ON(!page))
486 return -ENOMEM;
487 if (WARN_ON(!pfn_valid(page_to_pfn(page))))
488 return -EINVAL;
489
490 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
491 (*nr)++;
492 } while (pte++, addr += PAGE_SIZE, addr != end);
493 *mask |= PGTBL_PTE_MODIFIED;
494 return 0;
495 }
496
vmap_pages_pmd_range(pud_t * pud,unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages,int * nr,pgtbl_mod_mask * mask)497 static int vmap_pages_pmd_range(pud_t *pud, unsigned long addr,
498 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
499 pgtbl_mod_mask *mask)
500 {
501 pmd_t *pmd;
502 unsigned long next;
503
504 pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
505 if (!pmd)
506 return -ENOMEM;
507 do {
508 next = pmd_addr_end(addr, end);
509 if (vmap_pages_pte_range(pmd, addr, next, prot, pages, nr, mask))
510 return -ENOMEM;
511 } while (pmd++, addr = next, addr != end);
512 return 0;
513 }
514
vmap_pages_pud_range(p4d_t * p4d,unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages,int * nr,pgtbl_mod_mask * mask)515 static int vmap_pages_pud_range(p4d_t *p4d, unsigned long addr,
516 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
517 pgtbl_mod_mask *mask)
518 {
519 pud_t *pud;
520 unsigned long next;
521
522 pud = pud_alloc_track(&init_mm, p4d, addr, mask);
523 if (!pud)
524 return -ENOMEM;
525 do {
526 next = pud_addr_end(addr, end);
527 if (vmap_pages_pmd_range(pud, addr, next, prot, pages, nr, mask))
528 return -ENOMEM;
529 } while (pud++, addr = next, addr != end);
530 return 0;
531 }
532
vmap_pages_p4d_range(pgd_t * pgd,unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages,int * nr,pgtbl_mod_mask * mask)533 static int vmap_pages_p4d_range(pgd_t *pgd, unsigned long addr,
534 unsigned long end, pgprot_t prot, struct page **pages, int *nr,
535 pgtbl_mod_mask *mask)
536 {
537 p4d_t *p4d;
538 unsigned long next;
539
540 p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
541 if (!p4d)
542 return -ENOMEM;
543 do {
544 next = p4d_addr_end(addr, end);
545 if (vmap_pages_pud_range(p4d, addr, next, prot, pages, nr, mask))
546 return -ENOMEM;
547 } while (p4d++, addr = next, addr != end);
548 return 0;
549 }
550
vmap_small_pages_range_noflush(unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages)551 static int vmap_small_pages_range_noflush(unsigned long addr, unsigned long end,
552 pgprot_t prot, struct page **pages)
553 {
554 unsigned long start = addr;
555 pgd_t *pgd;
556 unsigned long next;
557 int err = 0;
558 int nr = 0;
559 pgtbl_mod_mask mask = 0;
560
561 BUG_ON(addr >= end);
562 pgd = pgd_offset_k(addr);
563 do {
564 next = pgd_addr_end(addr, end);
565 if (pgd_bad(*pgd))
566 mask |= PGTBL_PGD_MODIFIED;
567 err = vmap_pages_p4d_range(pgd, addr, next, prot, pages, &nr, &mask);
568 if (err)
569 return err;
570 } while (pgd++, addr = next, addr != end);
571
572 if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
573 arch_sync_kernel_mappings(start, end);
574
575 return 0;
576 }
577
578 /*
579 * vmap_pages_range_noflush is similar to vmap_pages_range, but does not
580 * flush caches.
581 *
582 * The caller is responsible for calling flush_cache_vmap() after this
583 * function returns successfully and before the addresses are accessed.
584 *
585 * This is an internal function only. Do not use outside mm/.
586 */
__vmap_pages_range_noflush(unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages,unsigned int page_shift)587 int __vmap_pages_range_noflush(unsigned long addr, unsigned long end,
588 pgprot_t prot, struct page **pages, unsigned int page_shift)
589 {
590 unsigned int i, nr = (end - addr) >> PAGE_SHIFT;
591
592 WARN_ON(page_shift < PAGE_SHIFT);
593
594 if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMALLOC) ||
595 page_shift == PAGE_SHIFT)
596 return vmap_small_pages_range_noflush(addr, end, prot, pages);
597
598 for (i = 0; i < nr; i += 1U << (page_shift - PAGE_SHIFT)) {
599 int err;
600
601 err = vmap_range_noflush(addr, addr + (1UL << page_shift),
602 page_to_phys(pages[i]), prot,
603 page_shift);
604 if (err)
605 return err;
606
607 addr += 1UL << page_shift;
608 }
609
610 return 0;
611 }
612
vmap_pages_range_noflush(unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages,unsigned int page_shift)613 int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
614 pgprot_t prot, struct page **pages, unsigned int page_shift)
615 {
616 kmsan_vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
617 return __vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
618 }
619
620 /**
621 * vmap_pages_range - map pages to a kernel virtual address
622 * @addr: start of the VM area to map
623 * @end: end of the VM area to map (non-inclusive)
624 * @prot: page protection flags to use
625 * @pages: pages to map (always PAGE_SIZE pages)
626 * @page_shift: maximum shift that the pages may be mapped with, @pages must
627 * be aligned and contiguous up to at least this shift.
628 *
629 * RETURNS:
630 * 0 on success, -errno on failure.
631 */
vmap_pages_range(unsigned long addr,unsigned long end,pgprot_t prot,struct page ** pages,unsigned int page_shift)632 static int vmap_pages_range(unsigned long addr, unsigned long end,
633 pgprot_t prot, struct page **pages, unsigned int page_shift)
634 {
635 int err;
636
637 err = vmap_pages_range_noflush(addr, end, prot, pages, page_shift);
638 flush_cache_vmap(addr, end);
639 return err;
640 }
641
is_vmalloc_or_module_addr(const void * x)642 int is_vmalloc_or_module_addr(const void *x)
643 {
644 /*
645 * ARM, x86-64 and sparc64 put modules in a special place,
646 * and fall back on vmalloc() if that fails. Others
647 * just put it in the vmalloc space.
648 */
649 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
650 unsigned long addr = (unsigned long)kasan_reset_tag(x);
651 if (addr >= MODULES_VADDR && addr < MODULES_END)
652 return 1;
653 #endif
654 return is_vmalloc_addr(x);
655 }
656
657 /*
658 * Walk a vmap address to the struct page it maps. Huge vmap mappings will
659 * return the tail page that corresponds to the base page address, which
660 * matches small vmap mappings.
661 */
vmalloc_to_page(const void * vmalloc_addr)662 struct page *vmalloc_to_page(const void *vmalloc_addr)
663 {
664 unsigned long addr = (unsigned long) vmalloc_addr;
665 struct page *page = NULL;
666 pgd_t *pgd = pgd_offset_k(addr);
667 p4d_t *p4d;
668 pud_t *pud;
669 pmd_t *pmd;
670 pte_t *ptep, pte;
671
672 /*
673 * XXX we might need to change this if we add VIRTUAL_BUG_ON for
674 * architectures that do not vmalloc module space
675 */
676 VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
677
678 if (pgd_none(*pgd))
679 return NULL;
680 if (WARN_ON_ONCE(pgd_leaf(*pgd)))
681 return NULL; /* XXX: no allowance for huge pgd */
682 if (WARN_ON_ONCE(pgd_bad(*pgd)))
683 return NULL;
684
685 p4d = p4d_offset(pgd, addr);
686 if (p4d_none(*p4d))
687 return NULL;
688 if (p4d_leaf(*p4d))
689 return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT);
690 if (WARN_ON_ONCE(p4d_bad(*p4d)))
691 return NULL;
692
693 pud = pud_offset(p4d, addr);
694 if (pud_none(*pud))
695 return NULL;
696 if (pud_leaf(*pud))
697 return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
698 if (WARN_ON_ONCE(pud_bad(*pud)))
699 return NULL;
700
701 pmd = pmd_offset(pud, addr);
702 if (pmd_none(*pmd))
703 return NULL;
704 if (pmd_leaf(*pmd))
705 return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
706 if (WARN_ON_ONCE(pmd_bad(*pmd)))
707 return NULL;
708
709 ptep = pte_offset_map(pmd, addr);
710 pte = *ptep;
711 if (pte_present(pte))
712 page = pte_page(pte);
713 pte_unmap(ptep);
714
715 return page;
716 }
717 EXPORT_SYMBOL(vmalloc_to_page);
718
719 /*
720 * Map a vmalloc()-space virtual address to the physical page frame number.
721 */
vmalloc_to_pfn(const void * vmalloc_addr)722 unsigned long vmalloc_to_pfn(const void *vmalloc_addr)
723 {
724 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
725 }
726 EXPORT_SYMBOL(vmalloc_to_pfn);
727
728
729 /*** Global kva allocator ***/
730
731 #define DEBUG_AUGMENT_PROPAGATE_CHECK 0
732 #define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
733
734
735 static DEFINE_SPINLOCK(vmap_area_lock);
736 static DEFINE_SPINLOCK(free_vmap_area_lock);
737 /* Export for kexec only */
738 LIST_HEAD(vmap_area_list);
739 static struct rb_root vmap_area_root = RB_ROOT;
740 static bool vmap_initialized __read_mostly;
741
742 static struct rb_root purge_vmap_area_root = RB_ROOT;
743 static LIST_HEAD(purge_vmap_area_list);
744 static DEFINE_SPINLOCK(purge_vmap_area_lock);
745
746 /*
747 * This kmem_cache is used for vmap_area objects. Instead of
748 * allocating from slab we reuse an object from this cache to
749 * make things faster. Especially in "no edge" splitting of
750 * free block.
751 */
752 static struct kmem_cache *vmap_area_cachep;
753
754 /*
755 * This linked list is used in pair with free_vmap_area_root.
756 * It gives O(1) access to prev/next to perform fast coalescing.
757 */
758 static LIST_HEAD(free_vmap_area_list);
759
760 /*
761 * This augment red-black tree represents the free vmap space.
762 * All vmap_area objects in this tree are sorted by va->va_start
763 * address. It is used for allocation and merging when a vmap
764 * object is released.
765 *
766 * Each vmap_area node contains a maximum available free block
767 * of its sub-tree, right or left. Therefore it is possible to
768 * find a lowest match of free area.
769 */
770 static struct rb_root free_vmap_area_root = RB_ROOT;
771
772 /*
773 * Preload a CPU with one object for "no edge" split case. The
774 * aim is to get rid of allocations from the atomic context, thus
775 * to use more permissive allocation masks.
776 */
777 static DEFINE_PER_CPU(struct vmap_area *, ne_fit_preload_node);
778
779 static __always_inline unsigned long
va_size(struct vmap_area * va)780 va_size(struct vmap_area *va)
781 {
782 return (va->va_end - va->va_start);
783 }
784
785 static __always_inline unsigned long
get_subtree_max_size(struct rb_node * node)786 get_subtree_max_size(struct rb_node *node)
787 {
788 struct vmap_area *va;
789
790 va = rb_entry_safe(node, struct vmap_area, rb_node);
791 return va ? va->subtree_max_size : 0;
792 }
793
794 RB_DECLARE_CALLBACKS_MAX(static, free_vmap_area_rb_augment_cb,
795 struct vmap_area, rb_node, unsigned long, subtree_max_size, va_size)
796
797 static void purge_vmap_area_lazy(void);
798 static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
799 static void drain_vmap_area_work(struct work_struct *work);
800 static DECLARE_WORK(drain_vmap_work, drain_vmap_area_work);
801
802 static atomic_long_t nr_vmalloc_pages;
803
vmalloc_nr_pages(void)804 unsigned long vmalloc_nr_pages(void)
805 {
806 return atomic_long_read(&nr_vmalloc_pages);
807 }
808
809 /* Look up the first VA which satisfies addr < va_end, NULL if none. */
find_vmap_area_exceed_addr(unsigned long addr)810 static struct vmap_area *find_vmap_area_exceed_addr(unsigned long addr)
811 {
812 struct vmap_area *va = NULL;
813 struct rb_node *n = vmap_area_root.rb_node;
814
815 addr = (unsigned long)kasan_reset_tag((void *)addr);
816
817 while (n) {
818 struct vmap_area *tmp;
819
820 tmp = rb_entry(n, struct vmap_area, rb_node);
821 if (tmp->va_end > addr) {
822 va = tmp;
823 if (tmp->va_start <= addr)
824 break;
825
826 n = n->rb_left;
827 } else
828 n = n->rb_right;
829 }
830
831 return va;
832 }
833
__find_vmap_area(unsigned long addr,struct rb_root * root)834 static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root)
835 {
836 struct rb_node *n = root->rb_node;
837
838 addr = (unsigned long)kasan_reset_tag((void *)addr);
839
840 while (n) {
841 struct vmap_area *va;
842
843 va = rb_entry(n, struct vmap_area, rb_node);
844 if (addr < va->va_start)
845 n = n->rb_left;
846 else if (addr >= va->va_end)
847 n = n->rb_right;
848 else
849 return va;
850 }
851
852 return NULL;
853 }
854
855 /*
856 * This function returns back addresses of parent node
857 * and its left or right link for further processing.
858 *
859 * Otherwise NULL is returned. In that case all further
860 * steps regarding inserting of conflicting overlap range
861 * have to be declined and actually considered as a bug.
862 */
863 static __always_inline struct rb_node **
find_va_links(struct vmap_area * va,struct rb_root * root,struct rb_node * from,struct rb_node ** parent)864 find_va_links(struct vmap_area *va,
865 struct rb_root *root, struct rb_node *from,
866 struct rb_node **parent)
867 {
868 struct vmap_area *tmp_va;
869 struct rb_node **link;
870
871 if (root) {
872 link = &root->rb_node;
873 if (unlikely(!*link)) {
874 *parent = NULL;
875 return link;
876 }
877 } else {
878 link = &from;
879 }
880
881 /*
882 * Go to the bottom of the tree. When we hit the last point
883 * we end up with parent rb_node and correct direction, i name
884 * it link, where the new va->rb_node will be attached to.
885 */
886 do {
887 tmp_va = rb_entry(*link, struct vmap_area, rb_node);
888
889 /*
890 * During the traversal we also do some sanity check.
891 * Trigger the BUG() if there are sides(left/right)
892 * or full overlaps.
893 */
894 if (va->va_end <= tmp_va->va_start)
895 link = &(*link)->rb_left;
896 else if (va->va_start >= tmp_va->va_end)
897 link = &(*link)->rb_right;
898 else {
899 WARN(1, "vmalloc bug: 0x%lx-0x%lx overlaps with 0x%lx-0x%lx\n",
900 va->va_start, va->va_end, tmp_va->va_start, tmp_va->va_end);
901
902 return NULL;
903 }
904 } while (*link);
905
906 *parent = &tmp_va->rb_node;
907 return link;
908 }
909
910 static __always_inline struct list_head *
get_va_next_sibling(struct rb_node * parent,struct rb_node ** link)911 get_va_next_sibling(struct rb_node *parent, struct rb_node **link)
912 {
913 struct list_head *list;
914
915 if (unlikely(!parent))
916 /*
917 * The red-black tree where we try to find VA neighbors
918 * before merging or inserting is empty, i.e. it means
919 * there is no free vmap space. Normally it does not
920 * happen but we handle this case anyway.
921 */
922 return NULL;
923
924 list = &rb_entry(parent, struct vmap_area, rb_node)->list;
925 return (&parent->rb_right == link ? list->next : list);
926 }
927
928 static __always_inline void
__link_va(struct vmap_area * va,struct rb_root * root,struct rb_node * parent,struct rb_node ** link,struct list_head * head,bool augment)929 __link_va(struct vmap_area *va, struct rb_root *root,
930 struct rb_node *parent, struct rb_node **link,
931 struct list_head *head, bool augment)
932 {
933 /*
934 * VA is still not in the list, but we can
935 * identify its future previous list_head node.
936 */
937 if (likely(parent)) {
938 head = &rb_entry(parent, struct vmap_area, rb_node)->list;
939 if (&parent->rb_right != link)
940 head = head->prev;
941 }
942
943 /* Insert to the rb-tree */
944 rb_link_node(&va->rb_node, parent, link);
945 if (augment) {
946 /*
947 * Some explanation here. Just perform simple insertion
948 * to the tree. We do not set va->subtree_max_size to
949 * its current size before calling rb_insert_augmented().
950 * It is because we populate the tree from the bottom
951 * to parent levels when the node _is_ in the tree.
952 *
953 * Therefore we set subtree_max_size to zero after insertion,
954 * to let __augment_tree_propagate_from() puts everything to
955 * the correct order later on.
956 */
957 rb_insert_augmented(&va->rb_node,
958 root, &free_vmap_area_rb_augment_cb);
959 va->subtree_max_size = 0;
960 } else {
961 rb_insert_color(&va->rb_node, root);
962 }
963
964 /* Address-sort this list */
965 list_add(&va->list, head);
966 }
967
968 static __always_inline void
link_va(struct vmap_area * va,struct rb_root * root,struct rb_node * parent,struct rb_node ** link,struct list_head * head)969 link_va(struct vmap_area *va, struct rb_root *root,
970 struct rb_node *parent, struct rb_node **link,
971 struct list_head *head)
972 {
973 __link_va(va, root, parent, link, head, false);
974 }
975
976 static __always_inline void
link_va_augment(struct vmap_area * va,struct rb_root * root,struct rb_node * parent,struct rb_node ** link,struct list_head * head)977 link_va_augment(struct vmap_area *va, struct rb_root *root,
978 struct rb_node *parent, struct rb_node **link,
979 struct list_head *head)
980 {
981 __link_va(va, root, parent, link, head, true);
982 }
983
984 static __always_inline void
__unlink_va(struct vmap_area * va,struct rb_root * root,bool augment)985 __unlink_va(struct vmap_area *va, struct rb_root *root, bool augment)
986 {
987 if (WARN_ON(RB_EMPTY_NODE(&va->rb_node)))
988 return;
989
990 if (augment)
991 rb_erase_augmented(&va->rb_node,
992 root, &free_vmap_area_rb_augment_cb);
993 else
994 rb_erase(&va->rb_node, root);
995
996 list_del_init(&va->list);
997 RB_CLEAR_NODE(&va->rb_node);
998 }
999
1000 static __always_inline void
unlink_va(struct vmap_area * va,struct rb_root * root)1001 unlink_va(struct vmap_area *va, struct rb_root *root)
1002 {
1003 __unlink_va(va, root, false);
1004 }
1005
1006 static __always_inline void
unlink_va_augment(struct vmap_area * va,struct rb_root * root)1007 unlink_va_augment(struct vmap_area *va, struct rb_root *root)
1008 {
1009 __unlink_va(va, root, true);
1010 }
1011
1012 #if DEBUG_AUGMENT_PROPAGATE_CHECK
1013 /*
1014 * Gets called when remove the node and rotate.
1015 */
1016 static __always_inline unsigned long
compute_subtree_max_size(struct vmap_area * va)1017 compute_subtree_max_size(struct vmap_area *va)
1018 {
1019 return max3(va_size(va),
1020 get_subtree_max_size(va->rb_node.rb_left),
1021 get_subtree_max_size(va->rb_node.rb_right));
1022 }
1023
1024 static void
augment_tree_propagate_check(void)1025 augment_tree_propagate_check(void)
1026 {
1027 struct vmap_area *va;
1028 unsigned long computed_size;
1029
1030 list_for_each_entry(va, &free_vmap_area_list, list) {
1031 computed_size = compute_subtree_max_size(va);
1032 if (computed_size != va->subtree_max_size)
1033 pr_emerg("tree is corrupted: %lu, %lu\n",
1034 va_size(va), va->subtree_max_size);
1035 }
1036 }
1037 #endif
1038
1039 /*
1040 * This function populates subtree_max_size from bottom to upper
1041 * levels starting from VA point. The propagation must be done
1042 * when VA size is modified by changing its va_start/va_end. Or
1043 * in case of newly inserting of VA to the tree.
1044 *
1045 * It means that __augment_tree_propagate_from() must be called:
1046 * - After VA has been inserted to the tree(free path);
1047 * - After VA has been shrunk(allocation path);
1048 * - After VA has been increased(merging path).
1049 *
1050 * Please note that, it does not mean that upper parent nodes
1051 * and their subtree_max_size are recalculated all the time up
1052 * to the root node.
1053 *
1054 * 4--8
1055 * /\
1056 * / \
1057 * / \
1058 * 2--2 8--8
1059 *
1060 * For example if we modify the node 4, shrinking it to 2, then
1061 * no any modification is required. If we shrink the node 2 to 1
1062 * its subtree_max_size is updated only, and set to 1. If we shrink
1063 * the node 8 to 6, then its subtree_max_size is set to 6 and parent
1064 * node becomes 4--6.
1065 */
1066 static __always_inline void
augment_tree_propagate_from(struct vmap_area * va)1067 augment_tree_propagate_from(struct vmap_area *va)
1068 {
1069 /*
1070 * Populate the tree from bottom towards the root until
1071 * the calculated maximum available size of checked node
1072 * is equal to its current one.
1073 */
1074 free_vmap_area_rb_augment_cb_propagate(&va->rb_node, NULL);
1075
1076 #if DEBUG_AUGMENT_PROPAGATE_CHECK
1077 augment_tree_propagate_check();
1078 #endif
1079 }
1080
1081 static void
insert_vmap_area(struct vmap_area * va,struct rb_root * root,struct list_head * head)1082 insert_vmap_area(struct vmap_area *va,
1083 struct rb_root *root, struct list_head *head)
1084 {
1085 struct rb_node **link;
1086 struct rb_node *parent;
1087
1088 link = find_va_links(va, root, NULL, &parent);
1089 if (link)
1090 link_va(va, root, parent, link, head);
1091 }
1092
1093 static void
insert_vmap_area_augment(struct vmap_area * va,struct rb_node * from,struct rb_root * root,struct list_head * head)1094 insert_vmap_area_augment(struct vmap_area *va,
1095 struct rb_node *from, struct rb_root *root,
1096 struct list_head *head)
1097 {
1098 struct rb_node **link;
1099 struct rb_node *parent;
1100
1101 if (from)
1102 link = find_va_links(va, NULL, from, &parent);
1103 else
1104 link = find_va_links(va, root, NULL, &parent);
1105
1106 if (link) {
1107 link_va_augment(va, root, parent, link, head);
1108 augment_tree_propagate_from(va);
1109 }
1110 }
1111
1112 /*
1113 * Merge de-allocated chunk of VA memory with previous
1114 * and next free blocks. If coalesce is not done a new
1115 * free area is inserted. If VA has been merged, it is
1116 * freed.
1117 *
1118 * Please note, it can return NULL in case of overlap
1119 * ranges, followed by WARN() report. Despite it is a
1120 * buggy behaviour, a system can be alive and keep
1121 * ongoing.
1122 */
1123 static __always_inline struct vmap_area *
__merge_or_add_vmap_area(struct vmap_area * va,struct rb_root * root,struct list_head * head,bool augment)1124 __merge_or_add_vmap_area(struct vmap_area *va,
1125 struct rb_root *root, struct list_head *head, bool augment)
1126 {
1127 struct vmap_area *sibling;
1128 struct list_head *next;
1129 struct rb_node **link;
1130 struct rb_node *parent;
1131 bool merged = false;
1132
1133 /*
1134 * Find a place in the tree where VA potentially will be
1135 * inserted, unless it is merged with its sibling/siblings.
1136 */
1137 link = find_va_links(va, root, NULL, &parent);
1138 if (!link)
1139 return NULL;
1140
1141 /*
1142 * Get next node of VA to check if merging can be done.
1143 */
1144 next = get_va_next_sibling(parent, link);
1145 if (unlikely(next == NULL))
1146 goto insert;
1147
1148 /*
1149 * start end
1150 * | |
1151 * |<------VA------>|<-----Next----->|
1152 * | |
1153 * start end
1154 */
1155 if (next != head) {
1156 sibling = list_entry(next, struct vmap_area, list);
1157 if (sibling->va_start == va->va_end) {
1158 sibling->va_start = va->va_start;
1159
1160 /* Free vmap_area object. */
1161 kmem_cache_free(vmap_area_cachep, va);
1162
1163 /* Point to the new merged area. */
1164 va = sibling;
1165 merged = true;
1166 }
1167 }
1168
1169 /*
1170 * start end
1171 * | |
1172 * |<-----Prev----->|<------VA------>|
1173 * | |
1174 * start end
1175 */
1176 if (next->prev != head) {
1177 sibling = list_entry(next->prev, struct vmap_area, list);
1178 if (sibling->va_end == va->va_start) {
1179 /*
1180 * If both neighbors are coalesced, it is important
1181 * to unlink the "next" node first, followed by merging
1182 * with "previous" one. Otherwise the tree might not be
1183 * fully populated if a sibling's augmented value is
1184 * "normalized" because of rotation operations.
1185 */
1186 if (merged)
1187 __unlink_va(va, root, augment);
1188
1189 sibling->va_end = va->va_end;
1190
1191 /* Free vmap_area object. */
1192 kmem_cache_free(vmap_area_cachep, va);
1193
1194 /* Point to the new merged area. */
1195 va = sibling;
1196 merged = true;
1197 }
1198 }
1199
1200 insert:
1201 if (!merged)
1202 __link_va(va, root, parent, link, head, augment);
1203
1204 return va;
1205 }
1206
1207 static __always_inline struct vmap_area *
merge_or_add_vmap_area(struct vmap_area * va,struct rb_root * root,struct list_head * head)1208 merge_or_add_vmap_area(struct vmap_area *va,
1209 struct rb_root *root, struct list_head *head)
1210 {
1211 return __merge_or_add_vmap_area(va, root, head, false);
1212 }
1213
1214 static __always_inline struct vmap_area *
merge_or_add_vmap_area_augment(struct vmap_area * va,struct rb_root * root,struct list_head * head)1215 merge_or_add_vmap_area_augment(struct vmap_area *va,
1216 struct rb_root *root, struct list_head *head)
1217 {
1218 va = __merge_or_add_vmap_area(va, root, head, true);
1219 if (va)
1220 augment_tree_propagate_from(va);
1221
1222 return va;
1223 }
1224
1225 static __always_inline bool
is_within_this_va(struct vmap_area * va,unsigned long size,unsigned long align,unsigned long vstart)1226 is_within_this_va(struct vmap_area *va, unsigned long size,
1227 unsigned long align, unsigned long vstart)
1228 {
1229 unsigned long nva_start_addr;
1230
1231 if (va->va_start > vstart)
1232 nva_start_addr = ALIGN(va->va_start, align);
1233 else
1234 nva_start_addr = ALIGN(vstart, align);
1235
1236 /* Can be overflowed due to big size or alignment. */
1237 if (nva_start_addr + size < nva_start_addr ||
1238 nva_start_addr < vstart)
1239 return false;
1240
1241 return (nva_start_addr + size <= va->va_end);
1242 }
1243
1244 /*
1245 * Find the first free block(lowest start address) in the tree,
1246 * that will accomplish the request corresponding to passing
1247 * parameters. Please note, with an alignment bigger than PAGE_SIZE,
1248 * a search length is adjusted to account for worst case alignment
1249 * overhead.
1250 */
1251 static __always_inline struct vmap_area *
find_vmap_lowest_match(struct rb_root * root,unsigned long size,unsigned long align,unsigned long vstart,bool adjust_search_size)1252 find_vmap_lowest_match(struct rb_root *root, unsigned long size,
1253 unsigned long align, unsigned long vstart, bool adjust_search_size)
1254 {
1255 struct vmap_area *va;
1256 struct rb_node *node;
1257 unsigned long length;
1258
1259 /* Start from the root. */
1260 node = root->rb_node;
1261
1262 /* Adjust the search size for alignment overhead. */
1263 length = adjust_search_size ? size + align - 1 : size;
1264
1265 while (node) {
1266 va = rb_entry(node, struct vmap_area, rb_node);
1267
1268 if (get_subtree_max_size(node->rb_left) >= length &&
1269 vstart < va->va_start) {
1270 node = node->rb_left;
1271 } else {
1272 if (is_within_this_va(va, size, align, vstart))
1273 return va;
1274
1275 /*
1276 * Does not make sense to go deeper towards the right
1277 * sub-tree if it does not have a free block that is
1278 * equal or bigger to the requested search length.
1279 */
1280 if (get_subtree_max_size(node->rb_right) >= length) {
1281 node = node->rb_right;
1282 continue;
1283 }
1284
1285 /*
1286 * OK. We roll back and find the first right sub-tree,
1287 * that will satisfy the search criteria. It can happen
1288 * due to "vstart" restriction or an alignment overhead
1289 * that is bigger then PAGE_SIZE.
1290 */
1291 while ((node = rb_parent(node))) {
1292 va = rb_entry(node, struct vmap_area, rb_node);
1293 if (is_within_this_va(va, size, align, vstart))
1294 return va;
1295
1296 if (get_subtree_max_size(node->rb_right) >= length &&
1297 vstart <= va->va_start) {
1298 /*
1299 * Shift the vstart forward. Please note, we update it with
1300 * parent's start address adding "1" because we do not want
1301 * to enter same sub-tree after it has already been checked
1302 * and no suitable free block found there.
1303 */
1304 vstart = va->va_start + 1;
1305 node = node->rb_right;
1306 break;
1307 }
1308 }
1309 }
1310 }
1311
1312 return NULL;
1313 }
1314
1315 #if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
1316 #include <linux/random.h>
1317
1318 static struct vmap_area *
find_vmap_lowest_linear_match(struct list_head * head,unsigned long size,unsigned long align,unsigned long vstart)1319 find_vmap_lowest_linear_match(struct list_head *head, unsigned long size,
1320 unsigned long align, unsigned long vstart)
1321 {
1322 struct vmap_area *va;
1323
1324 list_for_each_entry(va, head, list) {
1325 if (!is_within_this_va(va, size, align, vstart))
1326 continue;
1327
1328 return va;
1329 }
1330
1331 return NULL;
1332 }
1333
1334 static void
find_vmap_lowest_match_check(struct rb_root * root,struct list_head * head,unsigned long size,unsigned long align)1335 find_vmap_lowest_match_check(struct rb_root *root, struct list_head *head,
1336 unsigned long size, unsigned long align)
1337 {
1338 struct vmap_area *va_1, *va_2;
1339 unsigned long vstart;
1340 unsigned int rnd;
1341
1342 get_random_bytes(&rnd, sizeof(rnd));
1343 vstart = VMALLOC_START + rnd;
1344
1345 va_1 = find_vmap_lowest_match(root, size, align, vstart, false);
1346 va_2 = find_vmap_lowest_linear_match(head, size, align, vstart);
1347
1348 if (va_1 != va_2)
1349 pr_emerg("not lowest: t: 0x%p, l: 0x%p, v: 0x%lx\n",
1350 va_1, va_2, vstart);
1351 }
1352 #endif
1353
1354 enum fit_type {
1355 NOTHING_FIT = 0,
1356 FL_FIT_TYPE = 1, /* full fit */
1357 LE_FIT_TYPE = 2, /* left edge fit */
1358 RE_FIT_TYPE = 3, /* right edge fit */
1359 NE_FIT_TYPE = 4 /* no edge fit */
1360 };
1361
1362 static __always_inline enum fit_type
classify_va_fit_type(struct vmap_area * va,unsigned long nva_start_addr,unsigned long size)1363 classify_va_fit_type(struct vmap_area *va,
1364 unsigned long nva_start_addr, unsigned long size)
1365 {
1366 enum fit_type type;
1367
1368 /* Check if it is within VA. */
1369 if (nva_start_addr < va->va_start ||
1370 nva_start_addr + size > va->va_end)
1371 return NOTHING_FIT;
1372
1373 /* Now classify. */
1374 if (va->va_start == nva_start_addr) {
1375 if (va->va_end == nva_start_addr + size)
1376 type = FL_FIT_TYPE;
1377 else
1378 type = LE_FIT_TYPE;
1379 } else if (va->va_end == nva_start_addr + size) {
1380 type = RE_FIT_TYPE;
1381 } else {
1382 type = NE_FIT_TYPE;
1383 }
1384
1385 return type;
1386 }
1387
1388 static __always_inline int
adjust_va_to_fit_type(struct rb_root * root,struct list_head * head,struct vmap_area * va,unsigned long nva_start_addr,unsigned long size)1389 adjust_va_to_fit_type(struct rb_root *root, struct list_head *head,
1390 struct vmap_area *va, unsigned long nva_start_addr,
1391 unsigned long size)
1392 {
1393 struct vmap_area *lva = NULL;
1394 enum fit_type type = classify_va_fit_type(va, nva_start_addr, size);
1395
1396 if (type == FL_FIT_TYPE) {
1397 /*
1398 * No need to split VA, it fully fits.
1399 *
1400 * | |
1401 * V NVA V
1402 * |---------------|
1403 */
1404 unlink_va_augment(va, root);
1405 kmem_cache_free(vmap_area_cachep, va);
1406 } else if (type == LE_FIT_TYPE) {
1407 /*
1408 * Split left edge of fit VA.
1409 *
1410 * | |
1411 * V NVA V R
1412 * |-------|-------|
1413 */
1414 va->va_start += size;
1415 } else if (type == RE_FIT_TYPE) {
1416 /*
1417 * Split right edge of fit VA.
1418 *
1419 * | |
1420 * L V NVA V
1421 * |-------|-------|
1422 */
1423 va->va_end = nva_start_addr;
1424 } else if (type == NE_FIT_TYPE) {
1425 /*
1426 * Split no edge of fit VA.
1427 *
1428 * | |
1429 * L V NVA V R
1430 * |---|-------|---|
1431 */
1432 lva = __this_cpu_xchg(ne_fit_preload_node, NULL);
1433 if (unlikely(!lva)) {
1434 /*
1435 * For percpu allocator we do not do any pre-allocation
1436 * and leave it as it is. The reason is it most likely
1437 * never ends up with NE_FIT_TYPE splitting. In case of
1438 * percpu allocations offsets and sizes are aligned to
1439 * fixed align request, i.e. RE_FIT_TYPE and FL_FIT_TYPE
1440 * are its main fitting cases.
1441 *
1442 * There are a few exceptions though, as an example it is
1443 * a first allocation (early boot up) when we have "one"
1444 * big free space that has to be split.
1445 *
1446 * Also we can hit this path in case of regular "vmap"
1447 * allocations, if "this" current CPU was not preloaded.
1448 * See the comment in alloc_vmap_area() why. If so, then
1449 * GFP_NOWAIT is used instead to get an extra object for
1450 * split purpose. That is rare and most time does not
1451 * occur.
1452 *
1453 * What happens if an allocation gets failed. Basically,
1454 * an "overflow" path is triggered to purge lazily freed
1455 * areas to free some memory, then, the "retry" path is
1456 * triggered to repeat one more time. See more details
1457 * in alloc_vmap_area() function.
1458 */
1459 lva = kmem_cache_alloc(vmap_area_cachep, GFP_NOWAIT);
1460 if (!lva)
1461 return -1;
1462 }
1463
1464 /*
1465 * Build the remainder.
1466 */
1467 lva->va_start = va->va_start;
1468 lva->va_end = nva_start_addr;
1469
1470 /*
1471 * Shrink this VA to remaining size.
1472 */
1473 va->va_start = nva_start_addr + size;
1474 } else {
1475 return -1;
1476 }
1477
1478 if (type != FL_FIT_TYPE) {
1479 augment_tree_propagate_from(va);
1480
1481 if (lva) /* type == NE_FIT_TYPE */
1482 insert_vmap_area_augment(lva, &va->rb_node, root, head);
1483 }
1484
1485 return 0;
1486 }
1487
1488 /*
1489 * Returns a start address of the newly allocated area, if success.
1490 * Otherwise a vend is returned that indicates failure.
1491 */
1492 static __always_inline unsigned long
__alloc_vmap_area(struct rb_root * root,struct list_head * head,unsigned long size,unsigned long align,unsigned long vstart,unsigned long vend)1493 __alloc_vmap_area(struct rb_root *root, struct list_head *head,
1494 unsigned long size, unsigned long align,
1495 unsigned long vstart, unsigned long vend)
1496 {
1497 bool adjust_search_size = true;
1498 unsigned long nva_start_addr;
1499 struct vmap_area *va;
1500 int ret;
1501
1502 /*
1503 * Do not adjust when:
1504 * a) align <= PAGE_SIZE, because it does not make any sense.
1505 * All blocks(their start addresses) are at least PAGE_SIZE
1506 * aligned anyway;
1507 * b) a short range where a requested size corresponds to exactly
1508 * specified [vstart:vend] interval and an alignment > PAGE_SIZE.
1509 * With adjusted search length an allocation would not succeed.
1510 */
1511 if (align <= PAGE_SIZE || (align > PAGE_SIZE && (vend - vstart) == size))
1512 adjust_search_size = false;
1513
1514 va = find_vmap_lowest_match(root, size, align, vstart, adjust_search_size);
1515 if (unlikely(!va))
1516 return vend;
1517
1518 if (va->va_start > vstart)
1519 nva_start_addr = ALIGN(va->va_start, align);
1520 else
1521 nva_start_addr = ALIGN(vstart, align);
1522
1523 /* Check the "vend" restriction. */
1524 if (nva_start_addr + size > vend)
1525 return vend;
1526
1527 /* Update the free vmap_area. */
1528 ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size);
1529 if (WARN_ON_ONCE(ret))
1530 return vend;
1531
1532 #if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
1533 find_vmap_lowest_match_check(root, head, size, align);
1534 #endif
1535
1536 return nva_start_addr;
1537 }
1538
1539 /*
1540 * Free a region of KVA allocated by alloc_vmap_area
1541 */
free_vmap_area(struct vmap_area * va)1542 static void free_vmap_area(struct vmap_area *va)
1543 {
1544 /*
1545 * Remove from the busy tree/list.
1546 */
1547 spin_lock(&vmap_area_lock);
1548 unlink_va(va, &vmap_area_root);
1549 spin_unlock(&vmap_area_lock);
1550
1551 /*
1552 * Insert/Merge it back to the free tree/list.
1553 */
1554 spin_lock(&free_vmap_area_lock);
1555 merge_or_add_vmap_area_augment(va, &free_vmap_area_root, &free_vmap_area_list);
1556 spin_unlock(&free_vmap_area_lock);
1557 }
1558
1559 static inline void
preload_this_cpu_lock(spinlock_t * lock,gfp_t gfp_mask,int node)1560 preload_this_cpu_lock(spinlock_t *lock, gfp_t gfp_mask, int node)
1561 {
1562 struct vmap_area *va = NULL;
1563
1564 /*
1565 * Preload this CPU with one extra vmap_area object. It is used
1566 * when fit type of free area is NE_FIT_TYPE. It guarantees that
1567 * a CPU that does an allocation is preloaded.
1568 *
1569 * We do it in non-atomic context, thus it allows us to use more
1570 * permissive allocation masks to be more stable under low memory
1571 * condition and high memory pressure.
1572 */
1573 if (!this_cpu_read(ne_fit_preload_node))
1574 va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
1575
1576 spin_lock(lock);
1577
1578 if (va && __this_cpu_cmpxchg(ne_fit_preload_node, NULL, va))
1579 kmem_cache_free(vmap_area_cachep, va);
1580 }
1581
1582 /*
1583 * Allocate a region of KVA of the specified size and alignment, within the
1584 * vstart and vend.
1585 */
alloc_vmap_area(unsigned long size,unsigned long align,unsigned long vstart,unsigned long vend,int node,gfp_t gfp_mask)1586 static struct vmap_area *alloc_vmap_area(unsigned long size,
1587 unsigned long align,
1588 unsigned long vstart, unsigned long vend,
1589 int node, gfp_t gfp_mask)
1590 {
1591 struct vmap_area *va;
1592 unsigned long freed;
1593 unsigned long addr;
1594 int purged = 0;
1595 int ret;
1596
1597 BUG_ON(!size);
1598 BUG_ON(offset_in_page(size));
1599 BUG_ON(!is_power_of_2(align));
1600
1601 if (unlikely(!vmap_initialized))
1602 return ERR_PTR(-EBUSY);
1603
1604 might_sleep();
1605 gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
1606
1607 va = kmem_cache_alloc_node(vmap_area_cachep, gfp_mask, node);
1608 if (unlikely(!va))
1609 return ERR_PTR(-ENOMEM);
1610
1611 /*
1612 * Only scan the relevant parts containing pointers to other objects
1613 * to avoid false negatives.
1614 */
1615 kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask);
1616
1617 retry:
1618 preload_this_cpu_lock(&free_vmap_area_lock, gfp_mask, node);
1619 addr = __alloc_vmap_area(&free_vmap_area_root, &free_vmap_area_list,
1620 size, align, vstart, vend);
1621 spin_unlock(&free_vmap_area_lock);
1622
1623 /*
1624 * If an allocation fails, the "vend" address is
1625 * returned. Therefore trigger the overflow path.
1626 */
1627 if (unlikely(addr == vend))
1628 goto overflow;
1629
1630 va->va_start = addr;
1631 va->va_end = addr + size;
1632 va->vm = NULL;
1633
1634 spin_lock(&vmap_area_lock);
1635 insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
1636 spin_unlock(&vmap_area_lock);
1637
1638 BUG_ON(!IS_ALIGNED(va->va_start, align));
1639 BUG_ON(va->va_start < vstart);
1640 BUG_ON(va->va_end > vend);
1641
1642 ret = kasan_populate_vmalloc(addr, size);
1643 if (ret) {
1644 free_vmap_area(va);
1645 return ERR_PTR(ret);
1646 }
1647
1648 return va;
1649
1650 overflow:
1651 if (!purged) {
1652 purge_vmap_area_lazy();
1653 purged = 1;
1654 goto retry;
1655 }
1656
1657 freed = 0;
1658 blocking_notifier_call_chain(&vmap_notify_list, 0, &freed);
1659
1660 if (freed > 0) {
1661 purged = 0;
1662 goto retry;
1663 }
1664
1665 if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit())
1666 pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n",
1667 size);
1668
1669 kmem_cache_free(vmap_area_cachep, va);
1670 return ERR_PTR(-EBUSY);
1671 }
1672
register_vmap_purge_notifier(struct notifier_block * nb)1673 int register_vmap_purge_notifier(struct notifier_block *nb)
1674 {
1675 return blocking_notifier_chain_register(&vmap_notify_list, nb);
1676 }
1677 EXPORT_SYMBOL_GPL(register_vmap_purge_notifier);
1678
unregister_vmap_purge_notifier(struct notifier_block * nb)1679 int unregister_vmap_purge_notifier(struct notifier_block *nb)
1680 {
1681 return blocking_notifier_chain_unregister(&vmap_notify_list, nb);
1682 }
1683 EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier);
1684
1685 /*
1686 * lazy_max_pages is the maximum amount of virtual address space we gather up
1687 * before attempting to purge with a TLB flush.
1688 *
1689 * There is a tradeoff here: a larger number will cover more kernel page tables
1690 * and take slightly longer to purge, but it will linearly reduce the number of
1691 * global TLB flushes that must be performed. It would seem natural to scale
1692 * this number up linearly with the number of CPUs (because vmapping activity
1693 * could also scale linearly with the number of CPUs), however it is likely
1694 * that in practice, workloads might be constrained in other ways that mean
1695 * vmap activity will not scale linearly with CPUs. Also, I want to be
1696 * conservative and not introduce a big latency on huge systems, so go with
1697 * a less aggressive log scale. It will still be an improvement over the old
1698 * code, and it will be simple to change the scale factor if we find that it
1699 * becomes a problem on bigger systems.
1700 */
lazy_max_pages(void)1701 static unsigned long lazy_max_pages(void)
1702 {
1703 unsigned int log;
1704
1705 log = fls(num_online_cpus());
1706
1707 return log * (32UL * 1024 * 1024 / PAGE_SIZE);
1708 }
1709
1710 static atomic_long_t vmap_lazy_nr = ATOMIC_LONG_INIT(0);
1711
1712 /*
1713 * Serialize vmap purging. There is no actual critical section protected
1714 * by this lock, but we want to avoid concurrent calls for performance
1715 * reasons and to make the pcpu_get_vm_areas more deterministic.
1716 */
1717 static DEFINE_MUTEX(vmap_purge_lock);
1718
1719 /* for per-CPU blocks */
1720 static void purge_fragmented_blocks_allcpus(void);
1721
1722 /*
1723 * Purges all lazily-freed vmap areas.
1724 */
__purge_vmap_area_lazy(unsigned long start,unsigned long end)1725 static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
1726 {
1727 unsigned long resched_threshold;
1728 struct list_head local_purge_list;
1729 struct vmap_area *va, *n_va;
1730
1731 lockdep_assert_held(&vmap_purge_lock);
1732
1733 spin_lock(&purge_vmap_area_lock);
1734 purge_vmap_area_root = RB_ROOT;
1735 list_replace_init(&purge_vmap_area_list, &local_purge_list);
1736 spin_unlock(&purge_vmap_area_lock);
1737
1738 if (unlikely(list_empty(&local_purge_list)))
1739 return false;
1740
1741 start = min(start,
1742 list_first_entry(&local_purge_list,
1743 struct vmap_area, list)->va_start);
1744
1745 end = max(end,
1746 list_last_entry(&local_purge_list,
1747 struct vmap_area, list)->va_end);
1748
1749 flush_tlb_kernel_range(start, end);
1750 resched_threshold = lazy_max_pages() << 1;
1751
1752 spin_lock(&free_vmap_area_lock);
1753 list_for_each_entry_safe(va, n_va, &local_purge_list, list) {
1754 unsigned long nr = (va->va_end - va->va_start) >> PAGE_SHIFT;
1755 unsigned long orig_start = va->va_start;
1756 unsigned long orig_end = va->va_end;
1757
1758 /*
1759 * Finally insert or merge lazily-freed area. It is
1760 * detached and there is no need to "unlink" it from
1761 * anything.
1762 */
1763 va = merge_or_add_vmap_area_augment(va, &free_vmap_area_root,
1764 &free_vmap_area_list);
1765
1766 if (!va)
1767 continue;
1768
1769 if (is_vmalloc_or_module_addr((void *)orig_start))
1770 kasan_release_vmalloc(orig_start, orig_end,
1771 va->va_start, va->va_end);
1772
1773 atomic_long_sub(nr, &vmap_lazy_nr);
1774
1775 if (atomic_long_read(&vmap_lazy_nr) < resched_threshold)
1776 cond_resched_lock(&free_vmap_area_lock);
1777 }
1778 spin_unlock(&free_vmap_area_lock);
1779 return true;
1780 }
1781
1782 /*
1783 * Kick off a purge of the outstanding lazy areas.
1784 */
purge_vmap_area_lazy(void)1785 static void purge_vmap_area_lazy(void)
1786 {
1787 mutex_lock(&vmap_purge_lock);
1788 purge_fragmented_blocks_allcpus();
1789 __purge_vmap_area_lazy(ULONG_MAX, 0);
1790 mutex_unlock(&vmap_purge_lock);
1791 }
1792
drain_vmap_area_work(struct work_struct * work)1793 static void drain_vmap_area_work(struct work_struct *work)
1794 {
1795 unsigned long nr_lazy;
1796
1797 do {
1798 mutex_lock(&vmap_purge_lock);
1799 __purge_vmap_area_lazy(ULONG_MAX, 0);
1800 mutex_unlock(&vmap_purge_lock);
1801
1802 /* Recheck if further work is required. */
1803 nr_lazy = atomic_long_read(&vmap_lazy_nr);
1804 } while (nr_lazy > lazy_max_pages());
1805 }
1806
1807 /*
1808 * Free a vmap area, caller ensuring that the area has been unmapped
1809 * and flush_cache_vunmap had been called for the correct range
1810 * previously.
1811 */
free_vmap_area_noflush(struct vmap_area * va)1812 static void free_vmap_area_noflush(struct vmap_area *va)
1813 {
1814 unsigned long nr_lazy;
1815
1816 spin_lock(&vmap_area_lock);
1817 unlink_va(va, &vmap_area_root);
1818 spin_unlock(&vmap_area_lock);
1819
1820 nr_lazy = atomic_long_add_return((va->va_end - va->va_start) >>
1821 PAGE_SHIFT, &vmap_lazy_nr);
1822
1823 /*
1824 * Merge or place it to the purge tree/list.
1825 */
1826 spin_lock(&purge_vmap_area_lock);
1827 merge_or_add_vmap_area(va,
1828 &purge_vmap_area_root, &purge_vmap_area_list);
1829 spin_unlock(&purge_vmap_area_lock);
1830
1831 /* After this point, we may free va at any time */
1832 if (unlikely(nr_lazy > lazy_max_pages()))
1833 schedule_work(&drain_vmap_work);
1834 }
1835
1836 /*
1837 * Free and unmap a vmap area
1838 */
free_unmap_vmap_area(struct vmap_area * va)1839 static void free_unmap_vmap_area(struct vmap_area *va)
1840 {
1841 flush_cache_vunmap(va->va_start, va->va_end);
1842 vunmap_range_noflush(va->va_start, va->va_end);
1843 if (debug_pagealloc_enabled_static())
1844 flush_tlb_kernel_range(va->va_start, va->va_end);
1845
1846 free_vmap_area_noflush(va);
1847 }
1848
find_vmap_area(unsigned long addr)1849 struct vmap_area *find_vmap_area(unsigned long addr)
1850 {
1851 struct vmap_area *va;
1852
1853 spin_lock(&vmap_area_lock);
1854 va = __find_vmap_area(addr, &vmap_area_root);
1855 spin_unlock(&vmap_area_lock);
1856
1857 return va;
1858 }
1859
1860 /*** Per cpu kva allocator ***/
1861
1862 /*
1863 * vmap space is limited especially on 32 bit architectures. Ensure there is
1864 * room for at least 16 percpu vmap blocks per CPU.
1865 */
1866 /*
1867 * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able
1868 * to #define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START). Guess
1869 * instead (we just need a rough idea)
1870 */
1871 #if BITS_PER_LONG == 32
1872 #define VMALLOC_SPACE (128UL*1024*1024)
1873 #else
1874 #define VMALLOC_SPACE (128UL*1024*1024*1024)
1875 #endif
1876
1877 #define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE)
1878 #define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */
1879 #define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */
1880 #define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2)
1881 #define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */
1882 #define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */
1883 #define VMAP_BBMAP_BITS \
1884 VMAP_MIN(VMAP_BBMAP_BITS_MAX, \
1885 VMAP_MAX(VMAP_BBMAP_BITS_MIN, \
1886 VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16))
1887
1888 #define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE)
1889
1890 struct vmap_block_queue {
1891 spinlock_t lock;
1892 struct list_head free;
1893 };
1894
1895 struct vmap_block {
1896 spinlock_t lock;
1897 struct vmap_area *va;
1898 unsigned long free, dirty;
1899 unsigned long dirty_min, dirty_max; /*< dirty range */
1900 struct list_head free_list;
1901 struct rcu_head rcu_head;
1902 struct list_head purge;
1903 };
1904
1905 /* Queue of free and dirty vmap blocks, for allocation and flushing purposes */
1906 static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue);
1907
1908 /*
1909 * XArray of vmap blocks, indexed by address, to quickly find a vmap block
1910 * in the free path. Could get rid of this if we change the API to return a
1911 * "cookie" from alloc, to be passed to free. But no big deal yet.
1912 */
1913 static DEFINE_XARRAY(vmap_blocks);
1914
1915 /*
1916 * We should probably have a fallback mechanism to allocate virtual memory
1917 * out of partially filled vmap blocks. However vmap block sizing should be
1918 * fairly reasonable according to the vmalloc size, so it shouldn't be a
1919 * big problem.
1920 */
1921
addr_to_vb_idx(unsigned long addr)1922 static unsigned long addr_to_vb_idx(unsigned long addr)
1923 {
1924 addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1);
1925 addr /= VMAP_BLOCK_SIZE;
1926 return addr;
1927 }
1928
vmap_block_vaddr(unsigned long va_start,unsigned long pages_off)1929 static void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off)
1930 {
1931 unsigned long addr;
1932
1933 addr = va_start + (pages_off << PAGE_SHIFT);
1934 BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(va_start));
1935 return (void *)addr;
1936 }
1937
1938 /**
1939 * new_vmap_block - allocates new vmap_block and occupies 2^order pages in this
1940 * block. Of course pages number can't exceed VMAP_BBMAP_BITS
1941 * @order: how many 2^order pages should be occupied in newly allocated block
1942 * @gfp_mask: flags for the page level allocator
1943 *
1944 * Return: virtual address in a newly allocated block or ERR_PTR(-errno)
1945 */
new_vmap_block(unsigned int order,gfp_t gfp_mask)1946 static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
1947 {
1948 struct vmap_block_queue *vbq;
1949 struct vmap_block *vb;
1950 struct vmap_area *va;
1951 unsigned long vb_idx;
1952 int node, err;
1953 void *vaddr;
1954
1955 node = numa_node_id();
1956
1957 vb = kmalloc_node(sizeof(struct vmap_block),
1958 gfp_mask & GFP_RECLAIM_MASK, node);
1959 if (unlikely(!vb))
1960 return ERR_PTR(-ENOMEM);
1961
1962 va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE,
1963 VMALLOC_START, VMALLOC_END,
1964 node, gfp_mask);
1965 if (IS_ERR(va)) {
1966 kfree(vb);
1967 return ERR_CAST(va);
1968 }
1969
1970 vaddr = vmap_block_vaddr(va->va_start, 0);
1971 spin_lock_init(&vb->lock);
1972 vb->va = va;
1973 /* At least something should be left free */
1974 BUG_ON(VMAP_BBMAP_BITS <= (1UL << order));
1975 vb->free = VMAP_BBMAP_BITS - (1UL << order);
1976 vb->dirty = 0;
1977 vb->dirty_min = VMAP_BBMAP_BITS;
1978 vb->dirty_max = 0;
1979 INIT_LIST_HEAD(&vb->free_list);
1980
1981 vb_idx = addr_to_vb_idx(va->va_start);
1982 err = xa_insert(&vmap_blocks, vb_idx, vb, gfp_mask);
1983 if (err) {
1984 kfree(vb);
1985 free_vmap_area(va);
1986 return ERR_PTR(err);
1987 }
1988
1989 vbq = raw_cpu_ptr(&vmap_block_queue);
1990 spin_lock(&vbq->lock);
1991 list_add_tail_rcu(&vb->free_list, &vbq->free);
1992 spin_unlock(&vbq->lock);
1993
1994 return vaddr;
1995 }
1996
free_vmap_block(struct vmap_block * vb)1997 static void free_vmap_block(struct vmap_block *vb)
1998 {
1999 struct vmap_block *tmp;
2000
2001 tmp = xa_erase(&vmap_blocks, addr_to_vb_idx(vb->va->va_start));
2002 BUG_ON(tmp != vb);
2003
2004 free_vmap_area_noflush(vb->va);
2005 kfree_rcu(vb, rcu_head);
2006 }
2007
purge_fragmented_blocks(int cpu)2008 static void purge_fragmented_blocks(int cpu)
2009 {
2010 LIST_HEAD(purge);
2011 struct vmap_block *vb;
2012 struct vmap_block *n_vb;
2013 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
2014
2015 rcu_read_lock();
2016 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
2017
2018 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS))
2019 continue;
2020
2021 spin_lock(&vb->lock);
2022 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) {
2023 vb->free = 0; /* prevent further allocs after releasing lock */
2024 vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */
2025 vb->dirty_min = 0;
2026 vb->dirty_max = VMAP_BBMAP_BITS;
2027 spin_lock(&vbq->lock);
2028 list_del_rcu(&vb->free_list);
2029 spin_unlock(&vbq->lock);
2030 spin_unlock(&vb->lock);
2031 list_add_tail(&vb->purge, &purge);
2032 } else
2033 spin_unlock(&vb->lock);
2034 }
2035 rcu_read_unlock();
2036
2037 list_for_each_entry_safe(vb, n_vb, &purge, purge) {
2038 list_del(&vb->purge);
2039 free_vmap_block(vb);
2040 }
2041 }
2042
purge_fragmented_blocks_allcpus(void)2043 static void purge_fragmented_blocks_allcpus(void)
2044 {
2045 int cpu;
2046
2047 for_each_possible_cpu(cpu)
2048 purge_fragmented_blocks(cpu);
2049 }
2050
vb_alloc(unsigned long size,gfp_t gfp_mask)2051 static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
2052 {
2053 struct vmap_block_queue *vbq;
2054 struct vmap_block *vb;
2055 void *vaddr = NULL;
2056 unsigned int order;
2057
2058 BUG_ON(offset_in_page(size));
2059 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
2060 if (WARN_ON(size == 0)) {
2061 /*
2062 * Allocating 0 bytes isn't what caller wants since
2063 * get_order(0) returns funny result. Just warn and terminate
2064 * early.
2065 */
2066 return NULL;
2067 }
2068 order = get_order(size);
2069
2070 rcu_read_lock();
2071 vbq = raw_cpu_ptr(&vmap_block_queue);
2072 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
2073 unsigned long pages_off;
2074
2075 spin_lock(&vb->lock);
2076 if (vb->free < (1UL << order)) {
2077 spin_unlock(&vb->lock);
2078 continue;
2079 }
2080
2081 pages_off = VMAP_BBMAP_BITS - vb->free;
2082 vaddr = vmap_block_vaddr(vb->va->va_start, pages_off);
2083 vb->free -= 1UL << order;
2084 if (vb->free == 0) {
2085 spin_lock(&vbq->lock);
2086 list_del_rcu(&vb->free_list);
2087 spin_unlock(&vbq->lock);
2088 }
2089
2090 spin_unlock(&vb->lock);
2091 break;
2092 }
2093
2094 rcu_read_unlock();
2095
2096 /* Allocate new block if nothing was found */
2097 if (!vaddr)
2098 vaddr = new_vmap_block(order, gfp_mask);
2099
2100 return vaddr;
2101 }
2102
vb_free(unsigned long addr,unsigned long size)2103 static void vb_free(unsigned long addr, unsigned long size)
2104 {
2105 unsigned long offset;
2106 unsigned int order;
2107 struct vmap_block *vb;
2108
2109 BUG_ON(offset_in_page(size));
2110 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
2111
2112 flush_cache_vunmap(addr, addr + size);
2113
2114 order = get_order(size);
2115 offset = (addr & (VMAP_BLOCK_SIZE - 1)) >> PAGE_SHIFT;
2116 vb = xa_load(&vmap_blocks, addr_to_vb_idx(addr));
2117
2118 vunmap_range_noflush(addr, addr + size);
2119
2120 if (debug_pagealloc_enabled_static())
2121 flush_tlb_kernel_range(addr, addr + size);
2122
2123 spin_lock(&vb->lock);
2124
2125 /* Expand dirty range */
2126 vb->dirty_min = min(vb->dirty_min, offset);
2127 vb->dirty_max = max(vb->dirty_max, offset + (1UL << order));
2128
2129 vb->dirty += 1UL << order;
2130 if (vb->dirty == VMAP_BBMAP_BITS) {
2131 BUG_ON(vb->free);
2132 spin_unlock(&vb->lock);
2133 free_vmap_block(vb);
2134 } else
2135 spin_unlock(&vb->lock);
2136 }
2137
_vm_unmap_aliases(unsigned long start,unsigned long end,int flush)2138 static void _vm_unmap_aliases(unsigned long start, unsigned long end, int flush)
2139 {
2140 int cpu;
2141
2142 if (unlikely(!vmap_initialized))
2143 return;
2144
2145 might_sleep();
2146
2147 for_each_possible_cpu(cpu) {
2148 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu);
2149 struct vmap_block *vb;
2150
2151 rcu_read_lock();
2152 list_for_each_entry_rcu(vb, &vbq->free, free_list) {
2153 spin_lock(&vb->lock);
2154 if (vb->dirty && vb->dirty != VMAP_BBMAP_BITS) {
2155 unsigned long va_start = vb->va->va_start;
2156 unsigned long s, e;
2157
2158 s = va_start + (vb->dirty_min << PAGE_SHIFT);
2159 e = va_start + (vb->dirty_max << PAGE_SHIFT);
2160
2161 start = min(s, start);
2162 end = max(e, end);
2163
2164 flush = 1;
2165 }
2166 spin_unlock(&vb->lock);
2167 }
2168 rcu_read_unlock();
2169 }
2170
2171 mutex_lock(&vmap_purge_lock);
2172 purge_fragmented_blocks_allcpus();
2173 if (!__purge_vmap_area_lazy(start, end) && flush)
2174 flush_tlb_kernel_range(start, end);
2175 mutex_unlock(&vmap_purge_lock);
2176 }
2177
2178 /**
2179 * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
2180 *
2181 * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
2182 * to amortize TLB flushing overheads. What this means is that any page you
2183 * have now, may, in a former life, have been mapped into kernel virtual
2184 * address by the vmap layer and so there might be some CPUs with TLB entries
2185 * still referencing that page (additional to the regular 1:1 kernel mapping).
2186 *
2187 * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
2188 * be sure that none of the pages we have control over will have any aliases
2189 * from the vmap layer.
2190 */
vm_unmap_aliases(void)2191 void vm_unmap_aliases(void)
2192 {
2193 unsigned long start = ULONG_MAX, end = 0;
2194 int flush = 0;
2195
2196 _vm_unmap_aliases(start, end, flush);
2197 }
2198 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
2199
2200 /**
2201 * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram
2202 * @mem: the pointer returned by vm_map_ram
2203 * @count: the count passed to that vm_map_ram call (cannot unmap partial)
2204 */
vm_unmap_ram(const void * mem,unsigned int count)2205 void vm_unmap_ram(const void *mem, unsigned int count)
2206 {
2207 unsigned long size = (unsigned long)count << PAGE_SHIFT;
2208 unsigned long addr = (unsigned long)kasan_reset_tag(mem);
2209 struct vmap_area *va;
2210
2211 might_sleep();
2212 BUG_ON(!addr);
2213 BUG_ON(addr < VMALLOC_START);
2214 BUG_ON(addr > VMALLOC_END);
2215 BUG_ON(!PAGE_ALIGNED(addr));
2216
2217 kasan_poison_vmalloc(mem, size);
2218
2219 if (likely(count <= VMAP_MAX_ALLOC)) {
2220 debug_check_no_locks_freed(mem, size);
2221 vb_free(addr, size);
2222 return;
2223 }
2224
2225 va = find_vmap_area(addr);
2226 BUG_ON(!va);
2227 debug_check_no_locks_freed((void *)va->va_start,
2228 (va->va_end - va->va_start));
2229 free_unmap_vmap_area(va);
2230 }
2231 EXPORT_SYMBOL(vm_unmap_ram);
2232
2233 /**
2234 * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
2235 * @pages: an array of pointers to the pages to be mapped
2236 * @count: number of pages
2237 * @node: prefer to allocate data structures on this node
2238 *
2239 * If you use this function for less than VMAP_MAX_ALLOC pages, it could be
2240 * faster than vmap so it's good. But if you mix long-life and short-life
2241 * objects with vm_map_ram(), it could consume lots of address space through
2242 * fragmentation (especially on a 32bit machine). You could see failures in
2243 * the end. Please use this function for short-lived objects.
2244 *
2245 * Returns: a pointer to the address that has been mapped, or %NULL on failure
2246 */
vm_map_ram(struct page ** pages,unsigned int count,int node)2247 void *vm_map_ram(struct page **pages, unsigned int count, int node)
2248 {
2249 unsigned long size = (unsigned long)count << PAGE_SHIFT;
2250 unsigned long addr;
2251 void *mem;
2252
2253 if (likely(count <= VMAP_MAX_ALLOC)) {
2254 mem = vb_alloc(size, GFP_KERNEL);
2255 if (IS_ERR(mem))
2256 return NULL;
2257 addr = (unsigned long)mem;
2258 } else {
2259 struct vmap_area *va;
2260 va = alloc_vmap_area(size, PAGE_SIZE,
2261 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
2262 if (IS_ERR(va))
2263 return NULL;
2264
2265 addr = va->va_start;
2266 mem = (void *)addr;
2267 }
2268
2269 if (vmap_pages_range(addr, addr + size, PAGE_KERNEL,
2270 pages, PAGE_SHIFT) < 0) {
2271 vm_unmap_ram(mem, count);
2272 return NULL;
2273 }
2274
2275 /*
2276 * Mark the pages as accessible, now that they are mapped.
2277 * With hardware tag-based KASAN, marking is skipped for
2278 * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
2279 */
2280 mem = kasan_unpoison_vmalloc(mem, size, KASAN_VMALLOC_PROT_NORMAL);
2281
2282 return mem;
2283 }
2284 EXPORT_SYMBOL(vm_map_ram);
2285
2286 static struct vm_struct *vmlist __initdata;
2287
vm_area_page_order(struct vm_struct * vm)2288 static inline unsigned int vm_area_page_order(struct vm_struct *vm)
2289 {
2290 #ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
2291 return vm->page_order;
2292 #else
2293 return 0;
2294 #endif
2295 }
2296
set_vm_area_page_order(struct vm_struct * vm,unsigned int order)2297 static inline void set_vm_area_page_order(struct vm_struct *vm, unsigned int order)
2298 {
2299 #ifdef CONFIG_HAVE_ARCH_HUGE_VMALLOC
2300 vm->page_order = order;
2301 #else
2302 BUG_ON(order != 0);
2303 #endif
2304 }
2305
2306 /**
2307 * vm_area_add_early - add vmap area early during boot
2308 * @vm: vm_struct to add
2309 *
2310 * This function is used to add fixed kernel vm area to vmlist before
2311 * vmalloc_init() is called. @vm->addr, @vm->size, and @vm->flags
2312 * should contain proper values and the other fields should be zero.
2313 *
2314 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
2315 */
vm_area_add_early(struct vm_struct * vm)2316 void __init vm_area_add_early(struct vm_struct *vm)
2317 {
2318 struct vm_struct *tmp, **p;
2319
2320 BUG_ON(vmap_initialized);
2321 for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
2322 if (tmp->addr >= vm->addr) {
2323 BUG_ON(tmp->addr < vm->addr + vm->size);
2324 break;
2325 } else
2326 BUG_ON(tmp->addr + tmp->size > vm->addr);
2327 }
2328 vm->next = *p;
2329 *p = vm;
2330 }
2331
2332 /**
2333 * vm_area_register_early - register vmap area early during boot
2334 * @vm: vm_struct to register
2335 * @align: requested alignment
2336 *
2337 * This function is used to register kernel vm area before
2338 * vmalloc_init() is called. @vm->size and @vm->flags should contain
2339 * proper values on entry and other fields should be zero. On return,
2340 * vm->addr contains the allocated address.
2341 *
2342 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING.
2343 */
vm_area_register_early(struct vm_struct * vm,size_t align)2344 void __init vm_area_register_early(struct vm_struct *vm, size_t align)
2345 {
2346 unsigned long addr = ALIGN(VMALLOC_START, align);
2347 struct vm_struct *cur, **p;
2348
2349 BUG_ON(vmap_initialized);
2350
2351 for (p = &vmlist; (cur = *p) != NULL; p = &cur->next) {
2352 if ((unsigned long)cur->addr - addr >= vm->size)
2353 break;
2354 addr = ALIGN((unsigned long)cur->addr + cur->size, align);
2355 }
2356
2357 BUG_ON(addr > VMALLOC_END - vm->size);
2358 vm->addr = (void *)addr;
2359 vm->next = *p;
2360 *p = vm;
2361 kasan_populate_early_vm_area_shadow(vm->addr, vm->size);
2362 }
2363
vmap_init_free_space(void)2364 static void vmap_init_free_space(void)
2365 {
2366 unsigned long vmap_start = 1;
2367 const unsigned long vmap_end = ULONG_MAX;
2368 struct vmap_area *busy, *free;
2369
2370 /*
2371 * B F B B B F
2372 * -|-----|.....|-----|-----|-----|.....|-
2373 * | The KVA space |
2374 * |<--------------------------------->|
2375 */
2376 list_for_each_entry(busy, &vmap_area_list, list) {
2377 if (busy->va_start - vmap_start > 0) {
2378 free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
2379 if (!WARN_ON_ONCE(!free)) {
2380 free->va_start = vmap_start;
2381 free->va_end = busy->va_start;
2382
2383 insert_vmap_area_augment(free, NULL,
2384 &free_vmap_area_root,
2385 &free_vmap_area_list);
2386 }
2387 }
2388
2389 vmap_start = busy->va_end;
2390 }
2391
2392 if (vmap_end - vmap_start > 0) {
2393 free = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
2394 if (!WARN_ON_ONCE(!free)) {
2395 free->va_start = vmap_start;
2396 free->va_end = vmap_end;
2397
2398 insert_vmap_area_augment(free, NULL,
2399 &free_vmap_area_root,
2400 &free_vmap_area_list);
2401 }
2402 }
2403 }
2404
vmalloc_init(void)2405 void __init vmalloc_init(void)
2406 {
2407 struct vmap_area *va;
2408 struct vm_struct *tmp;
2409 int i;
2410
2411 /*
2412 * Create the cache for vmap_area objects.
2413 */
2414 vmap_area_cachep = KMEM_CACHE(vmap_area, SLAB_PANIC);
2415
2416 for_each_possible_cpu(i) {
2417 struct vmap_block_queue *vbq;
2418 struct vfree_deferred *p;
2419
2420 vbq = &per_cpu(vmap_block_queue, i);
2421 spin_lock_init(&vbq->lock);
2422 INIT_LIST_HEAD(&vbq->free);
2423 p = &per_cpu(vfree_deferred, i);
2424 init_llist_head(&p->list);
2425 INIT_WORK(&p->wq, free_work);
2426 }
2427
2428 /* Import existing vmlist entries. */
2429 for (tmp = vmlist; tmp; tmp = tmp->next) {
2430 va = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT);
2431 if (WARN_ON_ONCE(!va))
2432 continue;
2433
2434 va->va_start = (unsigned long)tmp->addr;
2435 va->va_end = va->va_start + tmp->size;
2436 va->vm = tmp;
2437 insert_vmap_area(va, &vmap_area_root, &vmap_area_list);
2438 }
2439
2440 /*
2441 * Now we can initialize a free vmap space.
2442 */
2443 vmap_init_free_space();
2444 vmap_initialized = true;
2445 }
2446
setup_vmalloc_vm_locked(struct vm_struct * vm,struct vmap_area * va,unsigned long flags,const void * caller)2447 static inline void setup_vmalloc_vm_locked(struct vm_struct *vm,
2448 struct vmap_area *va, unsigned long flags, const void *caller)
2449 {
2450 vm->flags = flags;
2451 vm->addr = (void *)va->va_start;
2452 vm->size = va->va_end - va->va_start;
2453 vm->caller = caller;
2454 va->vm = vm;
2455 }
2456
setup_vmalloc_vm(struct vm_struct * vm,struct vmap_area * va,unsigned long flags,const void * caller)2457 static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va,
2458 unsigned long flags, const void *caller)
2459 {
2460 spin_lock(&vmap_area_lock);
2461 setup_vmalloc_vm_locked(vm, va, flags, caller);
2462 spin_unlock(&vmap_area_lock);
2463 }
2464
clear_vm_uninitialized_flag(struct vm_struct * vm)2465 static void clear_vm_uninitialized_flag(struct vm_struct *vm)
2466 {
2467 /*
2468 * Before removing VM_UNINITIALIZED,
2469 * we should make sure that vm has proper values.
2470 * Pair with smp_rmb() in show_numa_info().
2471 */
2472 smp_wmb();
2473 vm->flags &= ~VM_UNINITIALIZED;
2474 }
2475
__get_vm_area_node(unsigned long size,unsigned long align,unsigned long shift,unsigned long flags,unsigned long start,unsigned long end,int node,gfp_t gfp_mask,const void * caller)2476 static struct vm_struct *__get_vm_area_node(unsigned long size,
2477 unsigned long align, unsigned long shift, unsigned long flags,
2478 unsigned long start, unsigned long end, int node,
2479 gfp_t gfp_mask, const void *caller)
2480 {
2481 struct vmap_area *va;
2482 struct vm_struct *area;
2483 unsigned long requested_size = size;
2484
2485 BUG_ON(in_interrupt());
2486 size = ALIGN(size, 1ul << shift);
2487 if (unlikely(!size))
2488 return NULL;
2489
2490 if (flags & VM_IOREMAP)
2491 align = 1ul << clamp_t(int, get_count_order_long(size),
2492 PAGE_SHIFT, IOREMAP_MAX_ORDER);
2493
2494 area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
2495 if (unlikely(!area))
2496 return NULL;
2497
2498 if (!(flags & VM_NO_GUARD))
2499 size += PAGE_SIZE;
2500
2501 va = alloc_vmap_area(size, align, start, end, node, gfp_mask);
2502 if (IS_ERR(va)) {
2503 kfree(area);
2504 return NULL;
2505 }
2506
2507 setup_vmalloc_vm(area, va, flags, caller);
2508
2509 /*
2510 * Mark pages for non-VM_ALLOC mappings as accessible. Do it now as a
2511 * best-effort approach, as they can be mapped outside of vmalloc code.
2512 * For VM_ALLOC mappings, the pages are marked as accessible after
2513 * getting mapped in __vmalloc_node_range().
2514 * With hardware tag-based KASAN, marking is skipped for
2515 * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
2516 */
2517 if (!(flags & VM_ALLOC))
2518 area->addr = kasan_unpoison_vmalloc(area->addr, requested_size,
2519 KASAN_VMALLOC_PROT_NORMAL);
2520
2521 return area;
2522 }
2523
__get_vm_area_caller(unsigned long size,unsigned long flags,unsigned long start,unsigned long end,const void * caller)2524 struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
2525 unsigned long start, unsigned long end,
2526 const void *caller)
2527 {
2528 return __get_vm_area_node(size, 1, PAGE_SHIFT, flags, start, end,
2529 NUMA_NO_NODE, GFP_KERNEL, caller);
2530 }
2531
2532 /**
2533 * get_vm_area - reserve a contiguous kernel virtual area
2534 * @size: size of the area
2535 * @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC
2536 *
2537 * Search an area of @size in the kernel virtual mapping area,
2538 * and reserved it for out purposes. Returns the area descriptor
2539 * on success or %NULL on failure.
2540 *
2541 * Return: the area descriptor on success or %NULL on failure.
2542 */
get_vm_area(unsigned long size,unsigned long flags)2543 struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
2544 {
2545 return __get_vm_area_node(size, 1, PAGE_SHIFT, flags,
2546 VMALLOC_START, VMALLOC_END,
2547 NUMA_NO_NODE, GFP_KERNEL,
2548 __builtin_return_address(0));
2549 }
2550
get_vm_area_caller(unsigned long size,unsigned long flags,const void * caller)2551 struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
2552 const void *caller)
2553 {
2554 return __get_vm_area_node(size, 1, PAGE_SHIFT, flags,
2555 VMALLOC_START, VMALLOC_END,
2556 NUMA_NO_NODE, GFP_KERNEL, caller);
2557 }
2558
2559 /**
2560 * find_vm_area - find a continuous kernel virtual area
2561 * @addr: base address
2562 *
2563 * Search for the kernel VM area starting at @addr, and return it.
2564 * It is up to the caller to do all required locking to keep the returned
2565 * pointer valid.
2566 *
2567 * Return: the area descriptor on success or %NULL on failure.
2568 */
find_vm_area(const void * addr)2569 struct vm_struct *find_vm_area(const void *addr)
2570 {
2571 struct vmap_area *va;
2572
2573 va = find_vmap_area((unsigned long)addr);
2574 if (!va)
2575 return NULL;
2576
2577 return va->vm;
2578 }
2579
2580 /**
2581 * remove_vm_area - find and remove a continuous kernel virtual area
2582 * @addr: base address
2583 *
2584 * Search for the kernel VM area starting at @addr, and remove it.
2585 * This function returns the found VM area, but using it is NOT safe
2586 * on SMP machines, except for its size or flags.
2587 *
2588 * Return: the area descriptor on success or %NULL on failure.
2589 */
remove_vm_area(const void * addr)2590 struct vm_struct *remove_vm_area(const void *addr)
2591 {
2592 struct vmap_area *va;
2593
2594 might_sleep();
2595
2596 spin_lock(&vmap_area_lock);
2597 va = __find_vmap_area((unsigned long)addr, &vmap_area_root);
2598 if (va && va->vm) {
2599 struct vm_struct *vm = va->vm;
2600
2601 va->vm = NULL;
2602 spin_unlock(&vmap_area_lock);
2603
2604 kasan_free_module_shadow(vm);
2605 free_unmap_vmap_area(va);
2606
2607 return vm;
2608 }
2609
2610 spin_unlock(&vmap_area_lock);
2611 return NULL;
2612 }
2613
set_area_direct_map(const struct vm_struct * area,int (* set_direct_map)(struct page * page))2614 static inline void set_area_direct_map(const struct vm_struct *area,
2615 int (*set_direct_map)(struct page *page))
2616 {
2617 int i;
2618
2619 /* HUGE_VMALLOC passes small pages to set_direct_map */
2620 for (i = 0; i < area->nr_pages; i++)
2621 if (page_address(area->pages[i]))
2622 set_direct_map(area->pages[i]);
2623 }
2624
2625 /* Handle removing and resetting vm mappings related to the vm_struct. */
vm_remove_mappings(struct vm_struct * area,int deallocate_pages)2626 static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
2627 {
2628 unsigned long start = ULONG_MAX, end = 0;
2629 unsigned int page_order = vm_area_page_order(area);
2630 int flush_reset = area->flags & VM_FLUSH_RESET_PERMS;
2631 int flush_dmap = 0;
2632 int i;
2633
2634 remove_vm_area(area->addr);
2635
2636 /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */
2637 if (!flush_reset)
2638 return;
2639
2640 /*
2641 * If not deallocating pages, just do the flush of the VM area and
2642 * return.
2643 */
2644 if (!deallocate_pages) {
2645 vm_unmap_aliases();
2646 return;
2647 }
2648
2649 /*
2650 * If execution gets here, flush the vm mapping and reset the direct
2651 * map. Find the start and end range of the direct mappings to make sure
2652 * the vm_unmap_aliases() flush includes the direct map.
2653 */
2654 for (i = 0; i < area->nr_pages; i += 1U << page_order) {
2655 unsigned long addr = (unsigned long)page_address(area->pages[i]);
2656 if (addr) {
2657 unsigned long page_size;
2658
2659 page_size = PAGE_SIZE << page_order;
2660 start = min(addr, start);
2661 end = max(addr + page_size, end);
2662 flush_dmap = 1;
2663 }
2664 }
2665
2666 /*
2667 * Set direct map to something invalid so that it won't be cached if
2668 * there are any accesses after the TLB flush, then flush the TLB and
2669 * reset the direct map permissions to the default.
2670 */
2671 set_area_direct_map(area, set_direct_map_invalid_noflush);
2672 _vm_unmap_aliases(start, end, flush_dmap);
2673 set_area_direct_map(area, set_direct_map_default_noflush);
2674 }
2675
__vunmap(const void * addr,int deallocate_pages)2676 static void __vunmap(const void *addr, int deallocate_pages)
2677 {
2678 struct vm_struct *area;
2679
2680 if (!addr)
2681 return;
2682
2683 if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n",
2684 addr))
2685 return;
2686
2687 area = find_vm_area(addr);
2688 if (unlikely(!area)) {
2689 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
2690 addr);
2691 return;
2692 }
2693
2694 debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
2695 debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
2696
2697 kasan_poison_vmalloc(area->addr, get_vm_area_size(area));
2698
2699 vm_remove_mappings(area, deallocate_pages);
2700
2701 if (deallocate_pages) {
2702 int i;
2703
2704 for (i = 0; i < area->nr_pages; i++) {
2705 struct page *page = area->pages[i];
2706
2707 BUG_ON(!page);
2708 mod_memcg_page_state(page, MEMCG_VMALLOC, -1);
2709 /*
2710 * High-order allocs for huge vmallocs are split, so
2711 * can be freed as an array of order-0 allocations
2712 */
2713 __free_pages(page, 0);
2714 cond_resched();
2715 }
2716 atomic_long_sub(area->nr_pages, &nr_vmalloc_pages);
2717
2718 kvfree(area->pages);
2719 }
2720
2721 kfree(area);
2722 }
2723
__vfree_deferred(const void * addr)2724 static inline void __vfree_deferred(const void *addr)
2725 {
2726 /*
2727 * Use raw_cpu_ptr() because this can be called from preemptible
2728 * context. Preemption is absolutely fine here, because the llist_add()
2729 * implementation is lockless, so it works even if we are adding to
2730 * another cpu's list. schedule_work() should be fine with this too.
2731 */
2732 struct vfree_deferred *p = raw_cpu_ptr(&vfree_deferred);
2733
2734 if (llist_add((struct llist_node *)addr, &p->list))
2735 schedule_work(&p->wq);
2736 }
2737
2738 /**
2739 * vfree_atomic - release memory allocated by vmalloc()
2740 * @addr: memory base address
2741 *
2742 * This one is just like vfree() but can be called in any atomic context
2743 * except NMIs.
2744 */
vfree_atomic(const void * addr)2745 void vfree_atomic(const void *addr)
2746 {
2747 BUG_ON(in_nmi());
2748
2749 kmemleak_free(addr);
2750
2751 if (!addr)
2752 return;
2753 __vfree_deferred(addr);
2754 }
2755
__vfree(const void * addr)2756 static void __vfree(const void *addr)
2757 {
2758 if (unlikely(in_interrupt()))
2759 __vfree_deferred(addr);
2760 else
2761 __vunmap(addr, 1);
2762 }
2763
2764 /**
2765 * vfree - Release memory allocated by vmalloc()
2766 * @addr: Memory base address
2767 *
2768 * Free the virtually continuous memory area starting at @addr, as obtained
2769 * from one of the vmalloc() family of APIs. This will usually also free the
2770 * physical memory underlying the virtual allocation, but that memory is
2771 * reference counted, so it will not be freed until the last user goes away.
2772 *
2773 * If @addr is NULL, no operation is performed.
2774 *
2775 * Context:
2776 * May sleep if called *not* from interrupt context.
2777 * Must not be called in NMI context (strictly speaking, it could be
2778 * if we have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling
2779 * conventions for vfree() arch-dependent would be a really bad idea).
2780 */
vfree(const void * addr)2781 void vfree(const void *addr)
2782 {
2783 BUG_ON(in_nmi());
2784
2785 kmemleak_free(addr);
2786
2787 might_sleep_if(!in_interrupt());
2788
2789 if (!addr)
2790 return;
2791
2792 __vfree(addr);
2793 }
2794 EXPORT_SYMBOL(vfree);
2795
2796 /**
2797 * vunmap - release virtual mapping obtained by vmap()
2798 * @addr: memory base address
2799 *
2800 * Free the virtually contiguous memory area starting at @addr,
2801 * which was created from the page array passed to vmap().
2802 *
2803 * Must not be called in interrupt context.
2804 */
vunmap(const void * addr)2805 void vunmap(const void *addr)
2806 {
2807 BUG_ON(in_interrupt());
2808 might_sleep();
2809 if (addr)
2810 __vunmap(addr, 0);
2811 }
2812 EXPORT_SYMBOL(vunmap);
2813
2814 /**
2815 * vmap - map an array of pages into virtually contiguous space
2816 * @pages: array of page pointers
2817 * @count: number of pages to map
2818 * @flags: vm_area->flags
2819 * @prot: page protection for the mapping
2820 *
2821 * Maps @count pages from @pages into contiguous kernel virtual space.
2822 * If @flags contains %VM_MAP_PUT_PAGES the ownership of the pages array itself
2823 * (which must be kmalloc or vmalloc memory) and one reference per pages in it
2824 * are transferred from the caller to vmap(), and will be freed / dropped when
2825 * vfree() is called on the return value.
2826 *
2827 * Return: the address of the area or %NULL on failure
2828 */
vmap(struct page ** pages,unsigned int count,unsigned long flags,pgprot_t prot)2829 void *vmap(struct page **pages, unsigned int count,
2830 unsigned long flags, pgprot_t prot)
2831 {
2832 struct vm_struct *area;
2833 unsigned long addr;
2834 unsigned long size; /* In bytes */
2835
2836 might_sleep();
2837
2838 /*
2839 * Your top guard is someone else's bottom guard. Not having a top
2840 * guard compromises someone else's mappings too.
2841 */
2842 if (WARN_ON_ONCE(flags & VM_NO_GUARD))
2843 flags &= ~VM_NO_GUARD;
2844
2845 if (count > totalram_pages())
2846 return NULL;
2847
2848 size = (unsigned long)count << PAGE_SHIFT;
2849 area = get_vm_area_caller(size, flags, __builtin_return_address(0));
2850 if (!area)
2851 return NULL;
2852
2853 addr = (unsigned long)area->addr;
2854 if (vmap_pages_range(addr, addr + size, pgprot_nx(prot),
2855 pages, PAGE_SHIFT) < 0) {
2856 vunmap(area->addr);
2857 return NULL;
2858 }
2859
2860 if (flags & VM_MAP_PUT_PAGES) {
2861 area->pages = pages;
2862 area->nr_pages = count;
2863 }
2864 return area->addr;
2865 }
2866 EXPORT_SYMBOL(vmap);
2867
2868 #ifdef CONFIG_VMAP_PFN
2869 struct vmap_pfn_data {
2870 unsigned long *pfns;
2871 pgprot_t prot;
2872 unsigned int idx;
2873 };
2874
vmap_pfn_apply(pte_t * pte,unsigned long addr,void * private)2875 static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private)
2876 {
2877 struct vmap_pfn_data *data = private;
2878
2879 if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx])))
2880 return -EINVAL;
2881 *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
2882 return 0;
2883 }
2884
2885 /**
2886 * vmap_pfn - map an array of PFNs into virtually contiguous space
2887 * @pfns: array of PFNs
2888 * @count: number of pages to map
2889 * @prot: page protection for the mapping
2890 *
2891 * Maps @count PFNs from @pfns into contiguous kernel virtual space and returns
2892 * the start address of the mapping.
2893 */
vmap_pfn(unsigned long * pfns,unsigned int count,pgprot_t prot)2894 void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot)
2895 {
2896 struct vmap_pfn_data data = { .pfns = pfns, .prot = pgprot_nx(prot) };
2897 struct vm_struct *area;
2898
2899 area = get_vm_area_caller(count * PAGE_SIZE, VM_IOREMAP,
2900 __builtin_return_address(0));
2901 if (!area)
2902 return NULL;
2903 if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
2904 count * PAGE_SIZE, vmap_pfn_apply, &data)) {
2905 free_vm_area(area);
2906 return NULL;
2907 }
2908 return area->addr;
2909 }
2910 EXPORT_SYMBOL_GPL(vmap_pfn);
2911 #endif /* CONFIG_VMAP_PFN */
2912
2913 static inline unsigned int
vm_area_alloc_pages(gfp_t gfp,int nid,unsigned int order,unsigned int nr_pages,struct page ** pages)2914 vm_area_alloc_pages(gfp_t gfp, int nid,
2915 unsigned int order, unsigned int nr_pages, struct page **pages)
2916 {
2917 unsigned int nr_allocated = 0;
2918 struct page *page;
2919 int i;
2920
2921 /*
2922 * For order-0 pages we make use of bulk allocator, if
2923 * the page array is partly or not at all populated due
2924 * to fails, fallback to a single page allocator that is
2925 * more permissive.
2926 */
2927 if (!order) {
2928 gfp_t bulk_gfp = gfp & ~__GFP_NOFAIL;
2929
2930 while (nr_allocated < nr_pages) {
2931 unsigned int nr, nr_pages_request;
2932
2933 /*
2934 * A maximum allowed request is hard-coded and is 100
2935 * pages per call. That is done in order to prevent a
2936 * long preemption off scenario in the bulk-allocator
2937 * so the range is [1:100].
2938 */
2939 nr_pages_request = min(100U, nr_pages - nr_allocated);
2940
2941 /* memory allocation should consider mempolicy, we can't
2942 * wrongly use nearest node when nid == NUMA_NO_NODE,
2943 * otherwise memory may be allocated in only one node,
2944 * but mempolicy wants to alloc memory by interleaving.
2945 */
2946 if (IS_ENABLED(CONFIG_NUMA) && nid == NUMA_NO_NODE)
2947 nr = alloc_pages_bulk_array_mempolicy(bulk_gfp,
2948 nr_pages_request,
2949 pages + nr_allocated);
2950
2951 else
2952 nr = alloc_pages_bulk_array_node(bulk_gfp, nid,
2953 nr_pages_request,
2954 pages + nr_allocated);
2955
2956 nr_allocated += nr;
2957 cond_resched();
2958
2959 /*
2960 * If zero or pages were obtained partly,
2961 * fallback to a single page allocator.
2962 */
2963 if (nr != nr_pages_request)
2964 break;
2965 }
2966 }
2967
2968 /* High-order pages or fallback path if "bulk" fails. */
2969
2970 while (nr_allocated < nr_pages) {
2971 if (fatal_signal_pending(current))
2972 break;
2973
2974 if (nid == NUMA_NO_NODE)
2975 page = alloc_pages(gfp, order);
2976 else
2977 page = alloc_pages_node(nid, gfp, order);
2978 if (unlikely(!page))
2979 break;
2980 /*
2981 * Higher order allocations must be able to be treated as
2982 * indepdenent small pages by callers (as they can with
2983 * small-page vmallocs). Some drivers do their own refcounting
2984 * on vmalloc_to_page() pages, some use page->mapping,
2985 * page->lru, etc.
2986 */
2987 if (order)
2988 split_page(page, order);
2989
2990 /*
2991 * Careful, we allocate and map page-order pages, but
2992 * tracking is done per PAGE_SIZE page so as to keep the
2993 * vm_struct APIs independent of the physical/mapped size.
2994 */
2995 for (i = 0; i < (1U << order); i++)
2996 pages[nr_allocated + i] = page + i;
2997
2998 cond_resched();
2999 nr_allocated += 1U << order;
3000 }
3001
3002 return nr_allocated;
3003 }
3004
__vmalloc_area_node(struct vm_struct * area,gfp_t gfp_mask,pgprot_t prot,unsigned int page_shift,int node)3005 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
3006 pgprot_t prot, unsigned int page_shift,
3007 int node)
3008 {
3009 const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO;
3010 bool nofail = gfp_mask & __GFP_NOFAIL;
3011 unsigned long addr = (unsigned long)area->addr;
3012 unsigned long size = get_vm_area_size(area);
3013 unsigned long array_size;
3014 unsigned int nr_small_pages = size >> PAGE_SHIFT;
3015 unsigned int page_order;
3016 unsigned int flags;
3017 int ret;
3018
3019 array_size = (unsigned long)nr_small_pages * sizeof(struct page *);
3020 gfp_mask |= __GFP_NOWARN;
3021 if (!(gfp_mask & (GFP_DMA | GFP_DMA32)))
3022 gfp_mask |= __GFP_HIGHMEM;
3023
3024 /* Please note that the recursion is strictly bounded. */
3025 if (array_size > PAGE_SIZE) {
3026 area->pages = __vmalloc_node(array_size, 1, nested_gfp, node,
3027 area->caller);
3028 } else {
3029 area->pages = kmalloc_node(array_size, nested_gfp, node);
3030 }
3031
3032 if (!area->pages) {
3033 warn_alloc(gfp_mask, NULL,
3034 "vmalloc error: size %lu, failed to allocated page array size %lu",
3035 nr_small_pages * PAGE_SIZE, array_size);
3036 free_vm_area(area);
3037 return NULL;
3038 }
3039
3040 set_vm_area_page_order(area, page_shift - PAGE_SHIFT);
3041 page_order = vm_area_page_order(area);
3042
3043 area->nr_pages = vm_area_alloc_pages(gfp_mask | __GFP_NOWARN,
3044 node, page_order, nr_small_pages, area->pages);
3045
3046 atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
3047 if (gfp_mask & __GFP_ACCOUNT) {
3048 int i;
3049
3050 for (i = 0; i < area->nr_pages; i++)
3051 mod_memcg_page_state(area->pages[i], MEMCG_VMALLOC, 1);
3052 }
3053
3054 /*
3055 * If not enough pages were obtained to accomplish an
3056 * allocation request, free them via __vfree() if any.
3057 */
3058 if (area->nr_pages != nr_small_pages) {
3059 warn_alloc(gfp_mask, NULL,
3060 "vmalloc error: size %lu, page order %u, failed to allocate pages",
3061 area->nr_pages * PAGE_SIZE, page_order);
3062 goto fail;
3063 }
3064
3065 /*
3066 * page tables allocations ignore external gfp mask, enforce it
3067 * by the scope API
3068 */
3069 if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
3070 flags = memalloc_nofs_save();
3071 else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
3072 flags = memalloc_noio_save();
3073
3074 do {
3075 ret = vmap_pages_range(addr, addr + size, prot, area->pages,
3076 page_shift);
3077 if (nofail && (ret < 0))
3078 schedule_timeout_uninterruptible(1);
3079 } while (nofail && (ret < 0));
3080
3081 if ((gfp_mask & (__GFP_FS | __GFP_IO)) == __GFP_IO)
3082 memalloc_nofs_restore(flags);
3083 else if ((gfp_mask & (__GFP_FS | __GFP_IO)) == 0)
3084 memalloc_noio_restore(flags);
3085
3086 if (ret < 0) {
3087 warn_alloc(gfp_mask, NULL,
3088 "vmalloc error: size %lu, failed to map pages",
3089 area->nr_pages * PAGE_SIZE);
3090 goto fail;
3091 }
3092
3093 return area->addr;
3094
3095 fail:
3096 __vfree(area->addr);
3097 return NULL;
3098 }
3099
3100 /**
3101 * __vmalloc_node_range - allocate virtually contiguous memory
3102 * @size: allocation size
3103 * @align: desired alignment
3104 * @start: vm area range start
3105 * @end: vm area range end
3106 * @gfp_mask: flags for the page level allocator
3107 * @prot: protection mask for the allocated pages
3108 * @vm_flags: additional vm area flags (e.g. %VM_NO_GUARD)
3109 * @node: node to use for allocation or NUMA_NO_NODE
3110 * @caller: caller's return address
3111 *
3112 * Allocate enough pages to cover @size from the page level
3113 * allocator with @gfp_mask flags. Please note that the full set of gfp
3114 * flags are not supported. GFP_KERNEL, GFP_NOFS and GFP_NOIO are all
3115 * supported.
3116 * Zone modifiers are not supported. From the reclaim modifiers
3117 * __GFP_DIRECT_RECLAIM is required (aka GFP_NOWAIT is not supported)
3118 * and only __GFP_NOFAIL is supported (i.e. __GFP_NORETRY and
3119 * __GFP_RETRY_MAYFAIL are not supported).
3120 *
3121 * __GFP_NOWARN can be used to suppress failures messages.
3122 *
3123 * Map them into contiguous kernel virtual space, using a pagetable
3124 * protection of @prot.
3125 *
3126 * Return: the address of the area or %NULL on failure
3127 */
__vmalloc_node_range(unsigned long size,unsigned long align,unsigned long start,unsigned long end,gfp_t gfp_mask,pgprot_t prot,unsigned long vm_flags,int node,const void * caller)3128 void *__vmalloc_node_range(unsigned long size, unsigned long align,
3129 unsigned long start, unsigned long end, gfp_t gfp_mask,
3130 pgprot_t prot, unsigned long vm_flags, int node,
3131 const void *caller)
3132 {
3133 struct vm_struct *area;
3134 void *ret;
3135 kasan_vmalloc_flags_t kasan_flags = KASAN_VMALLOC_NONE;
3136 unsigned long real_size = size;
3137 unsigned long real_align = align;
3138 unsigned int shift = PAGE_SHIFT;
3139
3140 if (WARN_ON_ONCE(!size))
3141 return NULL;
3142
3143 if ((size >> PAGE_SHIFT) > totalram_pages()) {
3144 warn_alloc(gfp_mask, NULL,
3145 "vmalloc error: size %lu, exceeds total pages",
3146 real_size);
3147 return NULL;
3148 }
3149
3150 if (vmap_allow_huge && (vm_flags & VM_ALLOW_HUGE_VMAP)) {
3151 unsigned long size_per_node;
3152
3153 /*
3154 * Try huge pages. Only try for PAGE_KERNEL allocations,
3155 * others like modules don't yet expect huge pages in
3156 * their allocations due to apply_to_page_range not
3157 * supporting them.
3158 */
3159
3160 size_per_node = size;
3161 if (node == NUMA_NO_NODE)
3162 size_per_node /= num_online_nodes();
3163 if (arch_vmap_pmd_supported(prot) && size_per_node >= PMD_SIZE)
3164 shift = PMD_SHIFT;
3165 else
3166 shift = arch_vmap_pte_supported_shift(size_per_node);
3167
3168 align = max(real_align, 1UL << shift);
3169 size = ALIGN(real_size, 1UL << shift);
3170 }
3171
3172 again:
3173 area = __get_vm_area_node(real_size, align, shift, VM_ALLOC |
3174 VM_UNINITIALIZED | vm_flags, start, end, node,
3175 gfp_mask, caller);
3176 if (!area) {
3177 bool nofail = gfp_mask & __GFP_NOFAIL;
3178 warn_alloc(gfp_mask, NULL,
3179 "vmalloc error: size %lu, vm_struct allocation failed%s",
3180 real_size, (nofail) ? ". Retrying." : "");
3181 if (nofail) {
3182 schedule_timeout_uninterruptible(1);
3183 goto again;
3184 }
3185 goto fail;
3186 }
3187
3188 /*
3189 * Prepare arguments for __vmalloc_area_node() and
3190 * kasan_unpoison_vmalloc().
3191 */
3192 if (pgprot_val(prot) == pgprot_val(PAGE_KERNEL)) {
3193 if (kasan_hw_tags_enabled()) {
3194 /*
3195 * Modify protection bits to allow tagging.
3196 * This must be done before mapping.
3197 */
3198 prot = arch_vmap_pgprot_tagged(prot);
3199
3200 /*
3201 * Skip page_alloc poisoning and zeroing for physical
3202 * pages backing VM_ALLOC mapping. Memory is instead
3203 * poisoned and zeroed by kasan_unpoison_vmalloc().
3204 */
3205 gfp_mask |= __GFP_SKIP_KASAN_UNPOISON | __GFP_SKIP_ZERO;
3206 }
3207
3208 /* Take note that the mapping is PAGE_KERNEL. */
3209 kasan_flags |= KASAN_VMALLOC_PROT_NORMAL;
3210 }
3211
3212 /* Allocate physical pages and map them into vmalloc space. */
3213 ret = __vmalloc_area_node(area, gfp_mask, prot, shift, node);
3214 if (!ret)
3215 goto fail;
3216
3217 /*
3218 * Mark the pages as accessible, now that they are mapped.
3219 * The condition for setting KASAN_VMALLOC_INIT should complement the
3220 * one in post_alloc_hook() with regards to the __GFP_SKIP_ZERO check
3221 * to make sure that memory is initialized under the same conditions.
3222 * Tag-based KASAN modes only assign tags to normal non-executable
3223 * allocations, see __kasan_unpoison_vmalloc().
3224 */
3225 kasan_flags |= KASAN_VMALLOC_VM_ALLOC;
3226 if (!want_init_on_free() && want_init_on_alloc(gfp_mask) &&
3227 (gfp_mask & __GFP_SKIP_ZERO))
3228 kasan_flags |= KASAN_VMALLOC_INIT;
3229 /* KASAN_VMALLOC_PROT_NORMAL already set if required. */
3230 area->addr = kasan_unpoison_vmalloc(area->addr, real_size, kasan_flags);
3231
3232 /*
3233 * In this function, newly allocated vm_struct has VM_UNINITIALIZED
3234 * flag. It means that vm_struct is not fully initialized.
3235 * Now, it is fully initialized, so remove this flag here.
3236 */
3237 clear_vm_uninitialized_flag(area);
3238
3239 size = PAGE_ALIGN(size);
3240 if (!(vm_flags & VM_DEFER_KMEMLEAK))
3241 kmemleak_vmalloc(area, size, gfp_mask);
3242
3243 return area->addr;
3244
3245 fail:
3246 if (shift > PAGE_SHIFT) {
3247 shift = PAGE_SHIFT;
3248 align = real_align;
3249 size = real_size;
3250 goto again;
3251 }
3252
3253 return NULL;
3254 }
3255
3256 /**
3257 * __vmalloc_node - allocate virtually contiguous memory
3258 * @size: allocation size
3259 * @align: desired alignment
3260 * @gfp_mask: flags for the page level allocator
3261 * @node: node to use for allocation or NUMA_NO_NODE
3262 * @caller: caller's return address
3263 *
3264 * Allocate enough pages to cover @size from the page level allocator with
3265 * @gfp_mask flags. Map them into contiguous kernel virtual space.
3266 *
3267 * Reclaim modifiers in @gfp_mask - __GFP_NORETRY, __GFP_RETRY_MAYFAIL
3268 * and __GFP_NOFAIL are not supported
3269 *
3270 * Any use of gfp flags outside of GFP_KERNEL should be consulted
3271 * with mm people.
3272 *
3273 * Return: pointer to the allocated memory or %NULL on error
3274 */
__vmalloc_node(unsigned long size,unsigned long align,gfp_t gfp_mask,int node,const void * caller)3275 void *__vmalloc_node(unsigned long size, unsigned long align,
3276 gfp_t gfp_mask, int node, const void *caller)
3277 {
3278 return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
3279 gfp_mask, PAGE_KERNEL, 0, node, caller);
3280 }
3281 /*
3282 * This is only for performance analysis of vmalloc and stress purpose.
3283 * It is required by vmalloc test module, therefore do not use it other
3284 * than that.
3285 */
3286 #ifdef CONFIG_TEST_VMALLOC_MODULE
3287 EXPORT_SYMBOL_GPL(__vmalloc_node);
3288 #endif
3289
__vmalloc(unsigned long size,gfp_t gfp_mask)3290 void *__vmalloc(unsigned long size, gfp_t gfp_mask)
3291 {
3292 return __vmalloc_node(size, 1, gfp_mask, NUMA_NO_NODE,
3293 __builtin_return_address(0));
3294 }
3295 EXPORT_SYMBOL(__vmalloc);
3296
3297 /**
3298 * vmalloc - allocate virtually contiguous memory
3299 * @size: allocation size
3300 *
3301 * Allocate enough pages to cover @size from the page level
3302 * allocator and map them into contiguous kernel virtual space.
3303 *
3304 * For tight control over page level allocator and protection flags
3305 * use __vmalloc() instead.
3306 *
3307 * Return: pointer to the allocated memory or %NULL on error
3308 */
vmalloc(unsigned long size)3309 void *vmalloc(unsigned long size)
3310 {
3311 return __vmalloc_node(size, 1, GFP_KERNEL, NUMA_NO_NODE,
3312 __builtin_return_address(0));
3313 }
3314 EXPORT_SYMBOL(vmalloc);
3315
3316 /**
3317 * vmalloc_huge - allocate virtually contiguous memory, allow huge pages
3318 * @size: allocation size
3319 * @gfp_mask: flags for the page level allocator
3320 *
3321 * Allocate enough pages to cover @size from the page level
3322 * allocator and map them into contiguous kernel virtual space.
3323 * If @size is greater than or equal to PMD_SIZE, allow using
3324 * huge pages for the memory
3325 *
3326 * Return: pointer to the allocated memory or %NULL on error
3327 */
vmalloc_huge(unsigned long size,gfp_t gfp_mask)3328 void *vmalloc_huge(unsigned long size, gfp_t gfp_mask)
3329 {
3330 return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
3331 gfp_mask, PAGE_KERNEL, VM_ALLOW_HUGE_VMAP,
3332 NUMA_NO_NODE, __builtin_return_address(0));
3333 }
3334 EXPORT_SYMBOL_GPL(vmalloc_huge);
3335
3336 /**
3337 * vzalloc - allocate virtually contiguous memory with zero fill
3338 * @size: allocation size
3339 *
3340 * Allocate enough pages to cover @size from the page level
3341 * allocator and map them into contiguous kernel virtual space.
3342 * The memory allocated is set to zero.
3343 *
3344 * For tight control over page level allocator and protection flags
3345 * use __vmalloc() instead.
3346 *
3347 * Return: pointer to the allocated memory or %NULL on error
3348 */
vzalloc(unsigned long size)3349 void *vzalloc(unsigned long size)
3350 {
3351 return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_ZERO, NUMA_NO_NODE,
3352 __builtin_return_address(0));
3353 }
3354 EXPORT_SYMBOL(vzalloc);
3355
3356 /**
3357 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace
3358 * @size: allocation size
3359 *
3360 * The resulting memory area is zeroed so it can be mapped to userspace
3361 * without leaking data.
3362 *
3363 * Return: pointer to the allocated memory or %NULL on error
3364 */
vmalloc_user(unsigned long size)3365 void *vmalloc_user(unsigned long size)
3366 {
3367 return __vmalloc_node_range(size, SHMLBA, VMALLOC_START, VMALLOC_END,
3368 GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL,
3369 VM_USERMAP, NUMA_NO_NODE,
3370 __builtin_return_address(0));
3371 }
3372 EXPORT_SYMBOL(vmalloc_user);
3373
3374 /**
3375 * vmalloc_node - allocate memory on a specific node
3376 * @size: allocation size
3377 * @node: numa node
3378 *
3379 * Allocate enough pages to cover @size from the page level
3380 * allocator and map them into contiguous kernel virtual space.
3381 *
3382 * For tight control over page level allocator and protection flags
3383 * use __vmalloc() instead.
3384 *
3385 * Return: pointer to the allocated memory or %NULL on error
3386 */
vmalloc_node(unsigned long size,int node)3387 void *vmalloc_node(unsigned long size, int node)
3388 {
3389 return __vmalloc_node(size, 1, GFP_KERNEL, node,
3390 __builtin_return_address(0));
3391 }
3392 EXPORT_SYMBOL(vmalloc_node);
3393
3394 /**
3395 * vzalloc_node - allocate memory on a specific node with zero fill
3396 * @size: allocation size
3397 * @node: numa node
3398 *
3399 * Allocate enough pages to cover @size from the page level
3400 * allocator and map them into contiguous kernel virtual space.
3401 * The memory allocated is set to zero.
3402 *
3403 * Return: pointer to the allocated memory or %NULL on error
3404 */
vzalloc_node(unsigned long size,int node)3405 void *vzalloc_node(unsigned long size, int node)
3406 {
3407 return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_ZERO, node,
3408 __builtin_return_address(0));
3409 }
3410 EXPORT_SYMBOL(vzalloc_node);
3411
3412 #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
3413 #define GFP_VMALLOC32 (GFP_DMA32 | GFP_KERNEL)
3414 #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
3415 #define GFP_VMALLOC32 (GFP_DMA | GFP_KERNEL)
3416 #else
3417 /*
3418 * 64b systems should always have either DMA or DMA32 zones. For others
3419 * GFP_DMA32 should do the right thing and use the normal zone.
3420 */
3421 #define GFP_VMALLOC32 (GFP_DMA32 | GFP_KERNEL)
3422 #endif
3423
3424 /**
3425 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
3426 * @size: allocation size
3427 *
3428 * Allocate enough 32bit PA addressable pages to cover @size from the
3429 * page level allocator and map them into contiguous kernel virtual space.
3430 *
3431 * Return: pointer to the allocated memory or %NULL on error
3432 */
vmalloc_32(unsigned long size)3433 void *vmalloc_32(unsigned long size)
3434 {
3435 return __vmalloc_node(size, 1, GFP_VMALLOC32, NUMA_NO_NODE,
3436 __builtin_return_address(0));
3437 }
3438 EXPORT_SYMBOL(vmalloc_32);
3439
3440 /**
3441 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
3442 * @size: allocation size
3443 *
3444 * The resulting memory area is 32bit addressable and zeroed so it can be
3445 * mapped to userspace without leaking data.
3446 *
3447 * Return: pointer to the allocated memory or %NULL on error
3448 */
vmalloc_32_user(unsigned long size)3449 void *vmalloc_32_user(unsigned long size)
3450 {
3451 return __vmalloc_node_range(size, SHMLBA, VMALLOC_START, VMALLOC_END,
3452 GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
3453 VM_USERMAP, NUMA_NO_NODE,
3454 __builtin_return_address(0));
3455 }
3456 EXPORT_SYMBOL(vmalloc_32_user);
3457
3458 /*
3459 * small helper routine , copy contents to buf from addr.
3460 * If the page is not present, fill zero.
3461 */
3462
aligned_vread(char * buf,char * addr,unsigned long count)3463 static int aligned_vread(char *buf, char *addr, unsigned long count)
3464 {
3465 struct page *p;
3466 int copied = 0;
3467
3468 while (count) {
3469 unsigned long offset, length;
3470
3471 offset = offset_in_page(addr);
3472 length = PAGE_SIZE - offset;
3473 if (length > count)
3474 length = count;
3475 p = vmalloc_to_page(addr);
3476 /*
3477 * To do safe access to this _mapped_ area, we need
3478 * lock. But adding lock here means that we need to add
3479 * overhead of vmalloc()/vfree() calls for this _debug_
3480 * interface, rarely used. Instead of that, we'll use
3481 * kmap() and get small overhead in this access function.
3482 */
3483 if (p) {
3484 /* We can expect USER0 is not used -- see vread() */
3485 void *map = kmap_atomic(p);
3486 memcpy(buf, map + offset, length);
3487 kunmap_atomic(map);
3488 } else
3489 memset(buf, 0, length);
3490
3491 addr += length;
3492 buf += length;
3493 copied += length;
3494 count -= length;
3495 }
3496 return copied;
3497 }
3498
3499 /**
3500 * vread() - read vmalloc area in a safe way.
3501 * @buf: buffer for reading data
3502 * @addr: vm address.
3503 * @count: number of bytes to be read.
3504 *
3505 * This function checks that addr is a valid vmalloc'ed area, and
3506 * copy data from that area to a given buffer. If the given memory range
3507 * of [addr...addr+count) includes some valid address, data is copied to
3508 * proper area of @buf. If there are memory holes, they'll be zero-filled.
3509 * IOREMAP area is treated as memory hole and no copy is done.
3510 *
3511 * If [addr...addr+count) doesn't includes any intersects with alive
3512 * vm_struct area, returns 0. @buf should be kernel's buffer.
3513 *
3514 * Note: In usual ops, vread() is never necessary because the caller
3515 * should know vmalloc() area is valid and can use memcpy().
3516 * This is for routines which have to access vmalloc area without
3517 * any information, as /proc/kcore.
3518 *
3519 * Return: number of bytes for which addr and buf should be increased
3520 * (same number as @count) or %0 if [addr...addr+count) doesn't
3521 * include any intersection with valid vmalloc area
3522 */
vread(char * buf,char * addr,unsigned long count)3523 long vread(char *buf, char *addr, unsigned long count)
3524 {
3525 struct vmap_area *va;
3526 struct vm_struct *vm;
3527 char *vaddr, *buf_start = buf;
3528 unsigned long buflen = count;
3529 unsigned long n;
3530
3531 addr = kasan_reset_tag(addr);
3532
3533 /* Don't allow overflow */
3534 if ((unsigned long) addr + count < count)
3535 count = -(unsigned long) addr;
3536
3537 spin_lock(&vmap_area_lock);
3538 va = find_vmap_area_exceed_addr((unsigned long)addr);
3539 if (!va)
3540 goto finished;
3541
3542 /* no intersects with alive vmap_area */
3543 if ((unsigned long)addr + count <= va->va_start)
3544 goto finished;
3545
3546 list_for_each_entry_from(va, &vmap_area_list, list) {
3547 if (!count)
3548 break;
3549
3550 if (!va->vm)
3551 continue;
3552
3553 vm = va->vm;
3554 vaddr = (char *) vm->addr;
3555 if (addr >= vaddr + get_vm_area_size(vm))
3556 continue;
3557 while (addr < vaddr) {
3558 if (count == 0)
3559 goto finished;
3560 *buf = '\0';
3561 buf++;
3562 addr++;
3563 count--;
3564 }
3565 n = vaddr + get_vm_area_size(vm) - addr;
3566 if (n > count)
3567 n = count;
3568 if (!(vm->flags & VM_IOREMAP))
3569 aligned_vread(buf, addr, n);
3570 else /* IOREMAP area is treated as memory hole */
3571 memset(buf, 0, n);
3572 buf += n;
3573 addr += n;
3574 count -= n;
3575 }
3576 finished:
3577 spin_unlock(&vmap_area_lock);
3578
3579 if (buf == buf_start)
3580 return 0;
3581 /* zero-fill memory holes */
3582 if (buf != buf_start + buflen)
3583 memset(buf, 0, buflen - (buf - buf_start));
3584
3585 return buflen;
3586 }
3587
3588 /**
3589 * remap_vmalloc_range_partial - map vmalloc pages to userspace
3590 * @vma: vma to cover
3591 * @uaddr: target user address to start at
3592 * @kaddr: virtual address of vmalloc kernel memory
3593 * @pgoff: offset from @kaddr to start at
3594 * @size: size of map area
3595 *
3596 * Returns: 0 for success, -Exxx on failure
3597 *
3598 * This function checks that @kaddr is a valid vmalloc'ed area,
3599 * and that it is big enough to cover the range starting at
3600 * @uaddr in @vma. Will return failure if that criteria isn't
3601 * met.
3602 *
3603 * Similar to remap_pfn_range() (see mm/memory.c)
3604 */
remap_vmalloc_range_partial(struct vm_area_struct * vma,unsigned long uaddr,void * kaddr,unsigned long pgoff,unsigned long size)3605 int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
3606 void *kaddr, unsigned long pgoff,
3607 unsigned long size)
3608 {
3609 struct vm_struct *area;
3610 unsigned long off;
3611 unsigned long end_index;
3612
3613 if (check_shl_overflow(pgoff, PAGE_SHIFT, &off))
3614 return -EINVAL;
3615
3616 size = PAGE_ALIGN(size);
3617
3618 if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr))
3619 return -EINVAL;
3620
3621 area = find_vm_area(kaddr);
3622 if (!area)
3623 return -EINVAL;
3624
3625 if (!(area->flags & (VM_USERMAP | VM_DMA_COHERENT)))
3626 return -EINVAL;
3627
3628 if (check_add_overflow(size, off, &end_index) ||
3629 end_index > get_vm_area_size(area))
3630 return -EINVAL;
3631 kaddr += off;
3632
3633 do {
3634 struct page *page = vmalloc_to_page(kaddr);
3635 int ret;
3636
3637 ret = vm_insert_page(vma, uaddr, page);
3638 if (ret)
3639 return ret;
3640
3641 uaddr += PAGE_SIZE;
3642 kaddr += PAGE_SIZE;
3643 size -= PAGE_SIZE;
3644 } while (size > 0);
3645
3646 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
3647
3648 return 0;
3649 }
3650
3651 /**
3652 * remap_vmalloc_range - map vmalloc pages to userspace
3653 * @vma: vma to cover (map full range of vma)
3654 * @addr: vmalloc memory
3655 * @pgoff: number of pages into addr before first page to map
3656 *
3657 * Returns: 0 for success, -Exxx on failure
3658 *
3659 * This function checks that addr is a valid vmalloc'ed area, and
3660 * that it is big enough to cover the vma. Will return failure if
3661 * that criteria isn't met.
3662 *
3663 * Similar to remap_pfn_range() (see mm/memory.c)
3664 */
remap_vmalloc_range(struct vm_area_struct * vma,void * addr,unsigned long pgoff)3665 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
3666 unsigned long pgoff)
3667 {
3668 return remap_vmalloc_range_partial(vma, vma->vm_start,
3669 addr, pgoff,
3670 vma->vm_end - vma->vm_start);
3671 }
3672 EXPORT_SYMBOL(remap_vmalloc_range);
3673
free_vm_area(struct vm_struct * area)3674 void free_vm_area(struct vm_struct *area)
3675 {
3676 struct vm_struct *ret;
3677 ret = remove_vm_area(area->addr);
3678 BUG_ON(ret != area);
3679 kfree(area);
3680 }
3681 EXPORT_SYMBOL_GPL(free_vm_area);
3682
3683 #ifdef CONFIG_SMP
node_to_va(struct rb_node * n)3684 static struct vmap_area *node_to_va(struct rb_node *n)
3685 {
3686 return rb_entry_safe(n, struct vmap_area, rb_node);
3687 }
3688
3689 /**
3690 * pvm_find_va_enclose_addr - find the vmap_area @addr belongs to
3691 * @addr: target address
3692 *
3693 * Returns: vmap_area if it is found. If there is no such area
3694 * the first highest(reverse order) vmap_area is returned
3695 * i.e. va->va_start < addr && va->va_end < addr or NULL
3696 * if there are no any areas before @addr.
3697 */
3698 static struct vmap_area *
pvm_find_va_enclose_addr(unsigned long addr)3699 pvm_find_va_enclose_addr(unsigned long addr)
3700 {
3701 struct vmap_area *va, *tmp;
3702 struct rb_node *n;
3703
3704 n = free_vmap_area_root.rb_node;
3705 va = NULL;
3706
3707 while (n) {
3708 tmp = rb_entry(n, struct vmap_area, rb_node);
3709 if (tmp->va_start <= addr) {
3710 va = tmp;
3711 if (tmp->va_end >= addr)
3712 break;
3713
3714 n = n->rb_right;
3715 } else {
3716 n = n->rb_left;
3717 }
3718 }
3719
3720 return va;
3721 }
3722
3723 /**
3724 * pvm_determine_end_from_reverse - find the highest aligned address
3725 * of free block below VMALLOC_END
3726 * @va:
3727 * in - the VA we start the search(reverse order);
3728 * out - the VA with the highest aligned end address.
3729 * @align: alignment for required highest address
3730 *
3731 * Returns: determined end address within vmap_area
3732 */
3733 static unsigned long
pvm_determine_end_from_reverse(struct vmap_area ** va,unsigned long align)3734 pvm_determine_end_from_reverse(struct vmap_area **va, unsigned long align)
3735 {
3736 unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
3737 unsigned long addr;
3738
3739 if (likely(*va)) {
3740 list_for_each_entry_from_reverse((*va),
3741 &free_vmap_area_list, list) {
3742 addr = min((*va)->va_end & ~(align - 1), vmalloc_end);
3743 if ((*va)->va_start < addr)
3744 return addr;
3745 }
3746 }
3747
3748 return 0;
3749 }
3750
3751 /**
3752 * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator
3753 * @offsets: array containing offset of each area
3754 * @sizes: array containing size of each area
3755 * @nr_vms: the number of areas to allocate
3756 * @align: alignment, all entries in @offsets and @sizes must be aligned to this
3757 *
3758 * Returns: kmalloc'd vm_struct pointer array pointing to allocated
3759 * vm_structs on success, %NULL on failure
3760 *
3761 * Percpu allocator wants to use congruent vm areas so that it can
3762 * maintain the offsets among percpu areas. This function allocates
3763 * congruent vmalloc areas for it with GFP_KERNEL. These areas tend to
3764 * be scattered pretty far, distance between two areas easily going up
3765 * to gigabytes. To avoid interacting with regular vmallocs, these
3766 * areas are allocated from top.
3767 *
3768 * Despite its complicated look, this allocator is rather simple. It
3769 * does everything top-down and scans free blocks from the end looking
3770 * for matching base. While scanning, if any of the areas do not fit the
3771 * base address is pulled down to fit the area. Scanning is repeated till
3772 * all the areas fit and then all necessary data structures are inserted
3773 * and the result is returned.
3774 */
pcpu_get_vm_areas(const unsigned long * offsets,const size_t * sizes,int nr_vms,size_t align)3775 struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
3776 const size_t *sizes, int nr_vms,
3777 size_t align)
3778 {
3779 const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align);
3780 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1);
3781 struct vmap_area **vas, *va;
3782 struct vm_struct **vms;
3783 int area, area2, last_area, term_area;
3784 unsigned long base, start, size, end, last_end, orig_start, orig_end;
3785 bool purged = false;
3786
3787 /* verify parameters and allocate data structures */
3788 BUG_ON(offset_in_page(align) || !is_power_of_2(align));
3789 for (last_area = 0, area = 0; area < nr_vms; area++) {
3790 start = offsets[area];
3791 end = start + sizes[area];
3792
3793 /* is everything aligned properly? */
3794 BUG_ON(!IS_ALIGNED(offsets[area], align));
3795 BUG_ON(!IS_ALIGNED(sizes[area], align));
3796
3797 /* detect the area with the highest address */
3798 if (start > offsets[last_area])
3799 last_area = area;
3800
3801 for (area2 = area + 1; area2 < nr_vms; area2++) {
3802 unsigned long start2 = offsets[area2];
3803 unsigned long end2 = start2 + sizes[area2];
3804
3805 BUG_ON(start2 < end && start < end2);
3806 }
3807 }
3808 last_end = offsets[last_area] + sizes[last_area];
3809
3810 if (vmalloc_end - vmalloc_start < last_end) {
3811 WARN_ON(true);
3812 return NULL;
3813 }
3814
3815 vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL);
3816 vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL);
3817 if (!vas || !vms)
3818 goto err_free2;
3819
3820 for (area = 0; area < nr_vms; area++) {
3821 vas[area] = kmem_cache_zalloc(vmap_area_cachep, GFP_KERNEL);
3822 vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL);
3823 if (!vas[area] || !vms[area])
3824 goto err_free;
3825 }
3826 retry:
3827 spin_lock(&free_vmap_area_lock);
3828
3829 /* start scanning - we scan from the top, begin with the last area */
3830 area = term_area = last_area;
3831 start = offsets[area];
3832 end = start + sizes[area];
3833
3834 va = pvm_find_va_enclose_addr(vmalloc_end);
3835 base = pvm_determine_end_from_reverse(&va, align) - end;
3836
3837 while (true) {
3838 /*
3839 * base might have underflowed, add last_end before
3840 * comparing.
3841 */
3842 if (base + last_end < vmalloc_start + last_end)
3843 goto overflow;
3844
3845 /*
3846 * Fitting base has not been found.
3847 */
3848 if (va == NULL)
3849 goto overflow;
3850
3851 /*
3852 * If required width exceeds current VA block, move
3853 * base downwards and then recheck.
3854 */
3855 if (base + end > va->va_end) {
3856 base = pvm_determine_end_from_reverse(&va, align) - end;
3857 term_area = area;
3858 continue;
3859 }
3860
3861 /*
3862 * If this VA does not fit, move base downwards and recheck.
3863 */
3864 if (base + start < va->va_start) {
3865 va = node_to_va(rb_prev(&va->rb_node));
3866 base = pvm_determine_end_from_reverse(&va, align) - end;
3867 term_area = area;
3868 continue;
3869 }
3870
3871 /*
3872 * This area fits, move on to the previous one. If
3873 * the previous one is the terminal one, we're done.
3874 */
3875 area = (area + nr_vms - 1) % nr_vms;
3876 if (area == term_area)
3877 break;
3878
3879 start = offsets[area];
3880 end = start + sizes[area];
3881 va = pvm_find_va_enclose_addr(base + end);
3882 }
3883
3884 /* we've found a fitting base, insert all va's */
3885 for (area = 0; area < nr_vms; area++) {
3886 int ret;
3887
3888 start = base + offsets[area];
3889 size = sizes[area];
3890
3891 va = pvm_find_va_enclose_addr(start);
3892 if (WARN_ON_ONCE(va == NULL))
3893 /* It is a BUG(), but trigger recovery instead. */
3894 goto recovery;
3895
3896 ret = adjust_va_to_fit_type(&free_vmap_area_root,
3897 &free_vmap_area_list,
3898 va, start, size);
3899 if (WARN_ON_ONCE(unlikely(ret)))
3900 /* It is a BUG(), but trigger recovery instead. */
3901 goto recovery;
3902
3903 /* Allocated area. */
3904 va = vas[area];
3905 va->va_start = start;
3906 va->va_end = start + size;
3907 }
3908
3909 spin_unlock(&free_vmap_area_lock);
3910
3911 /* populate the kasan shadow space */
3912 for (area = 0; area < nr_vms; area++) {
3913 if (kasan_populate_vmalloc(vas[area]->va_start, sizes[area]))
3914 goto err_free_shadow;
3915 }
3916
3917 /* insert all vm's */
3918 spin_lock(&vmap_area_lock);
3919 for (area = 0; area < nr_vms; area++) {
3920 insert_vmap_area(vas[area], &vmap_area_root, &vmap_area_list);
3921
3922 setup_vmalloc_vm_locked(vms[area], vas[area], VM_ALLOC,
3923 pcpu_get_vm_areas);
3924 }
3925 spin_unlock(&vmap_area_lock);
3926
3927 /*
3928 * Mark allocated areas as accessible. Do it now as a best-effort
3929 * approach, as they can be mapped outside of vmalloc code.
3930 * With hardware tag-based KASAN, marking is skipped for
3931 * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
3932 */
3933 for (area = 0; area < nr_vms; area++)
3934 vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr,
3935 vms[area]->size, KASAN_VMALLOC_PROT_NORMAL);
3936
3937 kfree(vas);
3938 return vms;
3939
3940 recovery:
3941 /*
3942 * Remove previously allocated areas. There is no
3943 * need in removing these areas from the busy tree,
3944 * because they are inserted only on the final step
3945 * and when pcpu_get_vm_areas() is success.
3946 */
3947 while (area--) {
3948 orig_start = vas[area]->va_start;
3949 orig_end = vas[area]->va_end;
3950 va = merge_or_add_vmap_area_augment(vas[area], &free_vmap_area_root,
3951 &free_vmap_area_list);
3952 if (va)
3953 kasan_release_vmalloc(orig_start, orig_end,
3954 va->va_start, va->va_end);
3955 vas[area] = NULL;
3956 }
3957
3958 overflow:
3959 spin_unlock(&free_vmap_area_lock);
3960 if (!purged) {
3961 purge_vmap_area_lazy();
3962 purged = true;
3963
3964 /* Before "retry", check if we recover. */
3965 for (area = 0; area < nr_vms; area++) {
3966 if (vas[area])
3967 continue;
3968
3969 vas[area] = kmem_cache_zalloc(
3970 vmap_area_cachep, GFP_KERNEL);
3971 if (!vas[area])
3972 goto err_free;
3973 }
3974
3975 goto retry;
3976 }
3977
3978 err_free:
3979 for (area = 0; area < nr_vms; area++) {
3980 if (vas[area])
3981 kmem_cache_free(vmap_area_cachep, vas[area]);
3982
3983 kfree(vms[area]);
3984 }
3985 err_free2:
3986 kfree(vas);
3987 kfree(vms);
3988 return NULL;
3989
3990 err_free_shadow:
3991 spin_lock(&free_vmap_area_lock);
3992 /*
3993 * We release all the vmalloc shadows, even the ones for regions that
3994 * hadn't been successfully added. This relies on kasan_release_vmalloc
3995 * being able to tolerate this case.
3996 */
3997 for (area = 0; area < nr_vms; area++) {
3998 orig_start = vas[area]->va_start;
3999 orig_end = vas[area]->va_end;
4000 va = merge_or_add_vmap_area_augment(vas[area], &free_vmap_area_root,
4001 &free_vmap_area_list);
4002 if (va)
4003 kasan_release_vmalloc(orig_start, orig_end,
4004 va->va_start, va->va_end);
4005 vas[area] = NULL;
4006 kfree(vms[area]);
4007 }
4008 spin_unlock(&free_vmap_area_lock);
4009 kfree(vas);
4010 kfree(vms);
4011 return NULL;
4012 }
4013
4014 /**
4015 * pcpu_free_vm_areas - free vmalloc areas for percpu allocator
4016 * @vms: vm_struct pointer array returned by pcpu_get_vm_areas()
4017 * @nr_vms: the number of allocated areas
4018 *
4019 * Free vm_structs and the array allocated by pcpu_get_vm_areas().
4020 */
pcpu_free_vm_areas(struct vm_struct ** vms,int nr_vms)4021 void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
4022 {
4023 int i;
4024
4025 for (i = 0; i < nr_vms; i++)
4026 free_vm_area(vms[i]);
4027 kfree(vms);
4028 }
4029 #endif /* CONFIG_SMP */
4030
4031 #ifdef CONFIG_PRINTK
vmalloc_dump_obj(void * object)4032 bool vmalloc_dump_obj(void *object)
4033 {
4034 struct vm_struct *vm;
4035 void *objp = (void *)PAGE_ALIGN((unsigned long)object);
4036
4037 vm = find_vm_area(objp);
4038 if (!vm)
4039 return false;
4040 pr_cont(" %u-page vmalloc region starting at %#lx allocated at %pS\n",
4041 vm->nr_pages, (unsigned long)vm->addr, vm->caller);
4042 return true;
4043 }
4044 #endif
4045
4046 #ifdef CONFIG_PROC_FS
s_start(struct seq_file * m,loff_t * pos)4047 static void *s_start(struct seq_file *m, loff_t *pos)
4048 __acquires(&vmap_purge_lock)
4049 __acquires(&vmap_area_lock)
4050 {
4051 mutex_lock(&vmap_purge_lock);
4052 spin_lock(&vmap_area_lock);
4053
4054 return seq_list_start(&vmap_area_list, *pos);
4055 }
4056
s_next(struct seq_file * m,void * p,loff_t * pos)4057 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4058 {
4059 return seq_list_next(p, &vmap_area_list, pos);
4060 }
4061
s_stop(struct seq_file * m,void * p)4062 static void s_stop(struct seq_file *m, void *p)
4063 __releases(&vmap_area_lock)
4064 __releases(&vmap_purge_lock)
4065 {
4066 spin_unlock(&vmap_area_lock);
4067 mutex_unlock(&vmap_purge_lock);
4068 }
4069
show_numa_info(struct seq_file * m,struct vm_struct * v)4070 static void show_numa_info(struct seq_file *m, struct vm_struct *v)
4071 {
4072 if (IS_ENABLED(CONFIG_NUMA)) {
4073 unsigned int nr, *counters = m->private;
4074 unsigned int step = 1U << vm_area_page_order(v);
4075
4076 if (!counters)
4077 return;
4078
4079 if (v->flags & VM_UNINITIALIZED)
4080 return;
4081 /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
4082 smp_rmb();
4083
4084 memset(counters, 0, nr_node_ids * sizeof(unsigned int));
4085
4086 for (nr = 0; nr < v->nr_pages; nr += step)
4087 counters[page_to_nid(v->pages[nr])] += step;
4088 for_each_node_state(nr, N_HIGH_MEMORY)
4089 if (counters[nr])
4090 seq_printf(m, " N%u=%u", nr, counters[nr]);
4091 }
4092 }
4093
show_purge_info(struct seq_file * m)4094 static void show_purge_info(struct seq_file *m)
4095 {
4096 struct vmap_area *va;
4097
4098 spin_lock(&purge_vmap_area_lock);
4099 list_for_each_entry(va, &purge_vmap_area_list, list) {
4100 seq_printf(m, "0x%pK-0x%pK %7ld unpurged vm_area\n",
4101 (void *)va->va_start, (void *)va->va_end,
4102 va->va_end - va->va_start);
4103 }
4104 spin_unlock(&purge_vmap_area_lock);
4105 }
4106
s_show(struct seq_file * m,void * p)4107 static int s_show(struct seq_file *m, void *p)
4108 {
4109 struct vmap_area *va;
4110 struct vm_struct *v;
4111
4112 va = list_entry(p, struct vmap_area, list);
4113
4114 /*
4115 * s_show can encounter race with remove_vm_area, !vm on behalf
4116 * of vmap area is being tear down or vm_map_ram allocation.
4117 */
4118 if (!va->vm) {
4119 seq_printf(m, "0x%pK-0x%pK %7ld vm_map_ram\n",
4120 (void *)va->va_start, (void *)va->va_end,
4121 va->va_end - va->va_start);
4122
4123 goto final;
4124 }
4125
4126 v = va->vm;
4127
4128 seq_printf(m, "0x%pK-0x%pK %7ld",
4129 v->addr, v->addr + v->size, v->size);
4130
4131 if (v->caller)
4132 seq_printf(m, " %pS", v->caller);
4133
4134 if (v->nr_pages)
4135 seq_printf(m, " pages=%d", v->nr_pages);
4136
4137 if (v->phys_addr)
4138 seq_printf(m, " phys=%pa", &v->phys_addr);
4139
4140 if (v->flags & VM_IOREMAP)
4141 seq_puts(m, " ioremap");
4142
4143 if (v->flags & VM_ALLOC)
4144 seq_puts(m, " vmalloc");
4145
4146 if (v->flags & VM_MAP)
4147 seq_puts(m, " vmap");
4148
4149 if (v->flags & VM_USERMAP)
4150 seq_puts(m, " user");
4151
4152 if (v->flags & VM_DMA_COHERENT)
4153 seq_puts(m, " dma-coherent");
4154
4155 if (is_vmalloc_addr(v->pages))
4156 seq_puts(m, " vpages");
4157
4158 show_numa_info(m, v);
4159 seq_putc(m, '\n');
4160
4161 /*
4162 * As a final step, dump "unpurged" areas.
4163 */
4164 final:
4165 if (list_is_last(&va->list, &vmap_area_list))
4166 show_purge_info(m);
4167
4168 return 0;
4169 }
4170
4171 static const struct seq_operations vmalloc_op = {
4172 .start = s_start,
4173 .next = s_next,
4174 .stop = s_stop,
4175 .show = s_show,
4176 };
4177
proc_vmalloc_init(void)4178 static int __init proc_vmalloc_init(void)
4179 {
4180 if (IS_ENABLED(CONFIG_NUMA))
4181 proc_create_seq_private("vmallocinfo", 0400, NULL,
4182 &vmalloc_op,
4183 nr_node_ids * sizeof(unsigned int), NULL);
4184 else
4185 proc_create_seq("vmallocinfo", 0400, NULL, &vmalloc_op);
4186 return 0;
4187 }
4188 module_init(proc_vmalloc_init);
4189
4190 #endif
4191