1 /* 2 * linux/mm/vmalloc.c 3 * 4 * Copyright (C) 1993 Linus Torvalds 5 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 6 * SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000 7 * Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002 8 * Numa awareness, Christoph Lameter, SGI, June 2005 9 */ 10 11 #include <linux/vmalloc.h> 12 #include <linux/mm.h> 13 #include <linux/module.h> 14 #include <linux/highmem.h> 15 #include <linux/sched/signal.h> 16 #include <linux/slab.h> 17 #include <linux/spinlock.h> 18 #include <linux/interrupt.h> 19 #include <linux/proc_fs.h> 20 #include <linux/seq_file.h> 21 #include <linux/debugobjects.h> 22 #include <linux/kallsyms.h> 23 #include <linux/list.h> 24 #include <linux/notifier.h> 25 #include <linux/rbtree.h> 26 #include <linux/radix-tree.h> 27 #include <linux/rcupdate.h> 28 #include <linux/pfn.h> 29 #include <linux/kmemleak.h> 30 #include <linux/atomic.h> 31 #include <linux/compiler.h> 32 #include <linux/llist.h> 33 #include <linux/bitops.h> 34 35 #include <linux/uaccess.h> 36 #include <asm/tlbflush.h> 37 #include <asm/shmparam.h> 38 39 #include "internal.h" 40 41 struct vfree_deferred { 42 struct llist_head list; 43 struct work_struct wq; 44 }; 45 static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred); 46 47 static void __vunmap(const void *, int); 48 49 static void free_work(struct work_struct *w) 50 { 51 struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq); 52 struct llist_node *llnode = llist_del_all(&p->list); 53 while (llnode) { 54 void *p = llnode; 55 llnode = llist_next(llnode); 56 __vunmap(p, 1); 57 } 58 } 59 60 /*** Page table manipulation functions ***/ 61 62 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end) 63 { 64 pte_t *pte; 65 66 pte = pte_offset_kernel(pmd, addr); 67 do { 68 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte); 69 WARN_ON(!pte_none(ptent) && !pte_present(ptent)); 70 } while (pte++, addr += PAGE_SIZE, addr != end); 71 } 72 73 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end) 74 { 75 pmd_t *pmd; 76 unsigned long next; 77 78 pmd = pmd_offset(pud, addr); 79 do { 80 next = pmd_addr_end(addr, end); 81 if (pmd_clear_huge(pmd)) 82 continue; 83 if (pmd_none_or_clear_bad(pmd)) 84 continue; 85 vunmap_pte_range(pmd, addr, next); 86 } while (pmd++, addr = next, addr != end); 87 } 88 89 static void vunmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end) 90 { 91 pud_t *pud; 92 unsigned long next; 93 94 pud = pud_offset(p4d, addr); 95 do { 96 next = pud_addr_end(addr, end); 97 if (pud_clear_huge(pud)) 98 continue; 99 if (pud_none_or_clear_bad(pud)) 100 continue; 101 vunmap_pmd_range(pud, addr, next); 102 } while (pud++, addr = next, addr != end); 103 } 104 105 static void vunmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end) 106 { 107 p4d_t *p4d; 108 unsigned long next; 109 110 p4d = p4d_offset(pgd, addr); 111 do { 112 next = p4d_addr_end(addr, end); 113 if (p4d_clear_huge(p4d)) 114 continue; 115 if (p4d_none_or_clear_bad(p4d)) 116 continue; 117 vunmap_pud_range(p4d, addr, next); 118 } while (p4d++, addr = next, addr != end); 119 } 120 121 static void vunmap_page_range(unsigned long addr, unsigned long end) 122 { 123 pgd_t *pgd; 124 unsigned long next; 125 126 BUG_ON(addr >= end); 127 pgd = pgd_offset_k(addr); 128 do { 129 next = pgd_addr_end(addr, end); 130 if (pgd_none_or_clear_bad(pgd)) 131 continue; 132 vunmap_p4d_range(pgd, addr, next); 133 } while (pgd++, addr = next, addr != end); 134 } 135 136 static int vmap_pte_range(pmd_t *pmd, unsigned long addr, 137 unsigned long end, pgprot_t prot, struct page **pages, int *nr) 138 { 139 pte_t *pte; 140 141 /* 142 * nr is a running index into the array which helps higher level 143 * callers keep track of where we're up to. 144 */ 145 146 pte = pte_alloc_kernel(pmd, addr); 147 if (!pte) 148 return -ENOMEM; 149 do { 150 struct page *page = pages[*nr]; 151 152 if (WARN_ON(!pte_none(*pte))) 153 return -EBUSY; 154 if (WARN_ON(!page)) 155 return -ENOMEM; 156 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); 157 (*nr)++; 158 } while (pte++, addr += PAGE_SIZE, addr != end); 159 return 0; 160 } 161 162 static int vmap_pmd_range(pud_t *pud, unsigned long addr, 163 unsigned long end, pgprot_t prot, struct page **pages, int *nr) 164 { 165 pmd_t *pmd; 166 unsigned long next; 167 168 pmd = pmd_alloc(&init_mm, pud, addr); 169 if (!pmd) 170 return -ENOMEM; 171 do { 172 next = pmd_addr_end(addr, end); 173 if (vmap_pte_range(pmd, addr, next, prot, pages, nr)) 174 return -ENOMEM; 175 } while (pmd++, addr = next, addr != end); 176 return 0; 177 } 178 179 static int vmap_pud_range(p4d_t *p4d, unsigned long addr, 180 unsigned long end, pgprot_t prot, struct page **pages, int *nr) 181 { 182 pud_t *pud; 183 unsigned long next; 184 185 pud = pud_alloc(&init_mm, p4d, addr); 186 if (!pud) 187 return -ENOMEM; 188 do { 189 next = pud_addr_end(addr, end); 190 if (vmap_pmd_range(pud, addr, next, prot, pages, nr)) 191 return -ENOMEM; 192 } while (pud++, addr = next, addr != end); 193 return 0; 194 } 195 196 static int vmap_p4d_range(pgd_t *pgd, unsigned long addr, 197 unsigned long end, pgprot_t prot, struct page **pages, int *nr) 198 { 199 p4d_t *p4d; 200 unsigned long next; 201 202 p4d = p4d_alloc(&init_mm, pgd, addr); 203 if (!p4d) 204 return -ENOMEM; 205 do { 206 next = p4d_addr_end(addr, end); 207 if (vmap_pud_range(p4d, addr, next, prot, pages, nr)) 208 return -ENOMEM; 209 } while (p4d++, addr = next, addr != end); 210 return 0; 211 } 212 213 /* 214 * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and 215 * will have pfns corresponding to the "pages" array. 216 * 217 * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N] 218 */ 219 static int vmap_page_range_noflush(unsigned long start, unsigned long end, 220 pgprot_t prot, struct page **pages) 221 { 222 pgd_t *pgd; 223 unsigned long next; 224 unsigned long addr = start; 225 int err = 0; 226 int nr = 0; 227 228 BUG_ON(addr >= end); 229 pgd = pgd_offset_k(addr); 230 do { 231 next = pgd_addr_end(addr, end); 232 err = vmap_p4d_range(pgd, addr, next, prot, pages, &nr); 233 if (err) 234 return err; 235 } while (pgd++, addr = next, addr != end); 236 237 return nr; 238 } 239 240 static int vmap_page_range(unsigned long start, unsigned long end, 241 pgprot_t prot, struct page **pages) 242 { 243 int ret; 244 245 ret = vmap_page_range_noflush(start, end, prot, pages); 246 flush_cache_vmap(start, end); 247 return ret; 248 } 249 250 int is_vmalloc_or_module_addr(const void *x) 251 { 252 /* 253 * ARM, x86-64 and sparc64 put modules in a special place, 254 * and fall back on vmalloc() if that fails. Others 255 * just put it in the vmalloc space. 256 */ 257 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR) 258 unsigned long addr = (unsigned long)x; 259 if (addr >= MODULES_VADDR && addr < MODULES_END) 260 return 1; 261 #endif 262 return is_vmalloc_addr(x); 263 } 264 265 /* 266 * Walk a vmap address to the struct page it maps. 267 */ 268 struct page *vmalloc_to_page(const void *vmalloc_addr) 269 { 270 unsigned long addr = (unsigned long) vmalloc_addr; 271 struct page *page = NULL; 272 pgd_t *pgd = pgd_offset_k(addr); 273 p4d_t *p4d; 274 pud_t *pud; 275 pmd_t *pmd; 276 pte_t *ptep, pte; 277 278 /* 279 * XXX we might need to change this if we add VIRTUAL_BUG_ON for 280 * architectures that do not vmalloc module space 281 */ 282 VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr)); 283 284 if (pgd_none(*pgd)) 285 return NULL; 286 p4d = p4d_offset(pgd, addr); 287 if (p4d_none(*p4d)) 288 return NULL; 289 pud = pud_offset(p4d, addr); 290 291 /* 292 * Don't dereference bad PUD or PMD (below) entries. This will also 293 * identify huge mappings, which we may encounter on architectures 294 * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be 295 * identified as vmalloc addresses by is_vmalloc_addr(), but are 296 * not [unambiguously] associated with a struct page, so there is 297 * no correct value to return for them. 298 */ 299 WARN_ON_ONCE(pud_bad(*pud)); 300 if (pud_none(*pud) || pud_bad(*pud)) 301 return NULL; 302 pmd = pmd_offset(pud, addr); 303 WARN_ON_ONCE(pmd_bad(*pmd)); 304 if (pmd_none(*pmd) || pmd_bad(*pmd)) 305 return NULL; 306 307 ptep = pte_offset_map(pmd, addr); 308 pte = *ptep; 309 if (pte_present(pte)) 310 page = pte_page(pte); 311 pte_unmap(ptep); 312 return page; 313 } 314 EXPORT_SYMBOL(vmalloc_to_page); 315 316 /* 317 * Map a vmalloc()-space virtual address to the physical page frame number. 318 */ 319 unsigned long vmalloc_to_pfn(const void *vmalloc_addr) 320 { 321 return page_to_pfn(vmalloc_to_page(vmalloc_addr)); 322 } 323 EXPORT_SYMBOL(vmalloc_to_pfn); 324 325 326 /*** Global kva allocator ***/ 327 328 #define VM_LAZY_FREE 0x02 329 #define VM_VM_AREA 0x04 330 331 static DEFINE_SPINLOCK(vmap_area_lock); 332 /* Export for kexec only */ 333 LIST_HEAD(vmap_area_list); 334 static LLIST_HEAD(vmap_purge_list); 335 static struct rb_root vmap_area_root = RB_ROOT; 336 337 /* The vmap cache globals are protected by vmap_area_lock */ 338 static struct rb_node *free_vmap_cache; 339 static unsigned long cached_hole_size; 340 static unsigned long cached_vstart; 341 static unsigned long cached_align; 342 343 static unsigned long vmap_area_pcpu_hole; 344 345 static struct vmap_area *__find_vmap_area(unsigned long addr) 346 { 347 struct rb_node *n = vmap_area_root.rb_node; 348 349 while (n) { 350 struct vmap_area *va; 351 352 va = rb_entry(n, struct vmap_area, rb_node); 353 if (addr < va->va_start) 354 n = n->rb_left; 355 else if (addr >= va->va_end) 356 n = n->rb_right; 357 else 358 return va; 359 } 360 361 return NULL; 362 } 363 364 static void __insert_vmap_area(struct vmap_area *va) 365 { 366 struct rb_node **p = &vmap_area_root.rb_node; 367 struct rb_node *parent = NULL; 368 struct rb_node *tmp; 369 370 while (*p) { 371 struct vmap_area *tmp_va; 372 373 parent = *p; 374 tmp_va = rb_entry(parent, struct vmap_area, rb_node); 375 if (va->va_start < tmp_va->va_end) 376 p = &(*p)->rb_left; 377 else if (va->va_end > tmp_va->va_start) 378 p = &(*p)->rb_right; 379 else 380 BUG(); 381 } 382 383 rb_link_node(&va->rb_node, parent, p); 384 rb_insert_color(&va->rb_node, &vmap_area_root); 385 386 /* address-sort this list */ 387 tmp = rb_prev(&va->rb_node); 388 if (tmp) { 389 struct vmap_area *prev; 390 prev = rb_entry(tmp, struct vmap_area, rb_node); 391 list_add_rcu(&va->list, &prev->list); 392 } else 393 list_add_rcu(&va->list, &vmap_area_list); 394 } 395 396 static void purge_vmap_area_lazy(void); 397 398 static BLOCKING_NOTIFIER_HEAD(vmap_notify_list); 399 400 /* 401 * Allocate a region of KVA of the specified size and alignment, within the 402 * vstart and vend. 403 */ 404 static struct vmap_area *alloc_vmap_area(unsigned long size, 405 unsigned long align, 406 unsigned long vstart, unsigned long vend, 407 int node, gfp_t gfp_mask) 408 { 409 struct vmap_area *va; 410 struct rb_node *n; 411 unsigned long addr; 412 int purged = 0; 413 struct vmap_area *first; 414 415 BUG_ON(!size); 416 BUG_ON(offset_in_page(size)); 417 BUG_ON(!is_power_of_2(align)); 418 419 might_sleep(); 420 421 va = kmalloc_node(sizeof(struct vmap_area), 422 gfp_mask & GFP_RECLAIM_MASK, node); 423 if (unlikely(!va)) 424 return ERR_PTR(-ENOMEM); 425 426 /* 427 * Only scan the relevant parts containing pointers to other objects 428 * to avoid false negatives. 429 */ 430 kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK); 431 432 retry: 433 spin_lock(&vmap_area_lock); 434 /* 435 * Invalidate cache if we have more permissive parameters. 436 * cached_hole_size notes the largest hole noticed _below_ 437 * the vmap_area cached in free_vmap_cache: if size fits 438 * into that hole, we want to scan from vstart to reuse 439 * the hole instead of allocating above free_vmap_cache. 440 * Note that __free_vmap_area may update free_vmap_cache 441 * without updating cached_hole_size or cached_align. 442 */ 443 if (!free_vmap_cache || 444 size < cached_hole_size || 445 vstart < cached_vstart || 446 align < cached_align) { 447 nocache: 448 cached_hole_size = 0; 449 free_vmap_cache = NULL; 450 } 451 /* record if we encounter less permissive parameters */ 452 cached_vstart = vstart; 453 cached_align = align; 454 455 /* find starting point for our search */ 456 if (free_vmap_cache) { 457 first = rb_entry(free_vmap_cache, struct vmap_area, rb_node); 458 addr = ALIGN(first->va_end, align); 459 if (addr < vstart) 460 goto nocache; 461 if (addr + size < addr) 462 goto overflow; 463 464 } else { 465 addr = ALIGN(vstart, align); 466 if (addr + size < addr) 467 goto overflow; 468 469 n = vmap_area_root.rb_node; 470 first = NULL; 471 472 while (n) { 473 struct vmap_area *tmp; 474 tmp = rb_entry(n, struct vmap_area, rb_node); 475 if (tmp->va_end >= addr) { 476 first = tmp; 477 if (tmp->va_start <= addr) 478 break; 479 n = n->rb_left; 480 } else 481 n = n->rb_right; 482 } 483 484 if (!first) 485 goto found; 486 } 487 488 /* from the starting point, walk areas until a suitable hole is found */ 489 while (addr + size > first->va_start && addr + size <= vend) { 490 if (addr + cached_hole_size < first->va_start) 491 cached_hole_size = first->va_start - addr; 492 addr = ALIGN(first->va_end, align); 493 if (addr + size < addr) 494 goto overflow; 495 496 if (list_is_last(&first->list, &vmap_area_list)) 497 goto found; 498 499 first = list_next_entry(first, list); 500 } 501 502 found: 503 if (addr + size > vend) 504 goto overflow; 505 506 va->va_start = addr; 507 va->va_end = addr + size; 508 va->flags = 0; 509 __insert_vmap_area(va); 510 free_vmap_cache = &va->rb_node; 511 spin_unlock(&vmap_area_lock); 512 513 BUG_ON(!IS_ALIGNED(va->va_start, align)); 514 BUG_ON(va->va_start < vstart); 515 BUG_ON(va->va_end > vend); 516 517 return va; 518 519 overflow: 520 spin_unlock(&vmap_area_lock); 521 if (!purged) { 522 purge_vmap_area_lazy(); 523 purged = 1; 524 goto retry; 525 } 526 527 if (gfpflags_allow_blocking(gfp_mask)) { 528 unsigned long freed = 0; 529 blocking_notifier_call_chain(&vmap_notify_list, 0, &freed); 530 if (freed > 0) { 531 purged = 0; 532 goto retry; 533 } 534 } 535 536 if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) 537 pr_warn("vmap allocation for size %lu failed: use vmalloc=<size> to increase size\n", 538 size); 539 kfree(va); 540 return ERR_PTR(-EBUSY); 541 } 542 543 int register_vmap_purge_notifier(struct notifier_block *nb) 544 { 545 return blocking_notifier_chain_register(&vmap_notify_list, nb); 546 } 547 EXPORT_SYMBOL_GPL(register_vmap_purge_notifier); 548 549 int unregister_vmap_purge_notifier(struct notifier_block *nb) 550 { 551 return blocking_notifier_chain_unregister(&vmap_notify_list, nb); 552 } 553 EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier); 554 555 static void __free_vmap_area(struct vmap_area *va) 556 { 557 BUG_ON(RB_EMPTY_NODE(&va->rb_node)); 558 559 if (free_vmap_cache) { 560 if (va->va_end < cached_vstart) { 561 free_vmap_cache = NULL; 562 } else { 563 struct vmap_area *cache; 564 cache = rb_entry(free_vmap_cache, struct vmap_area, rb_node); 565 if (va->va_start <= cache->va_start) { 566 free_vmap_cache = rb_prev(&va->rb_node); 567 /* 568 * We don't try to update cached_hole_size or 569 * cached_align, but it won't go very wrong. 570 */ 571 } 572 } 573 } 574 rb_erase(&va->rb_node, &vmap_area_root); 575 RB_CLEAR_NODE(&va->rb_node); 576 list_del_rcu(&va->list); 577 578 /* 579 * Track the highest possible candidate for pcpu area 580 * allocation. Areas outside of vmalloc area can be returned 581 * here too, consider only end addresses which fall inside 582 * vmalloc area proper. 583 */ 584 if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END) 585 vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end); 586 587 kfree_rcu(va, rcu_head); 588 } 589 590 /* 591 * Free a region of KVA allocated by alloc_vmap_area 592 */ 593 static void free_vmap_area(struct vmap_area *va) 594 { 595 spin_lock(&vmap_area_lock); 596 __free_vmap_area(va); 597 spin_unlock(&vmap_area_lock); 598 } 599 600 /* 601 * Clear the pagetable entries of a given vmap_area 602 */ 603 static void unmap_vmap_area(struct vmap_area *va) 604 { 605 vunmap_page_range(va->va_start, va->va_end); 606 } 607 608 static void vmap_debug_free_range(unsigned long start, unsigned long end) 609 { 610 /* 611 * Unmap page tables and force a TLB flush immediately if pagealloc 612 * debugging is enabled. This catches use after free bugs similarly to 613 * those in linear kernel virtual address space after a page has been 614 * freed. 615 * 616 * All the lazy freeing logic is still retained, in order to minimise 617 * intrusiveness of this debugging feature. 618 * 619 * This is going to be *slow* (linear kernel virtual address debugging 620 * doesn't do a broadcast TLB flush so it is a lot faster). 621 */ 622 if (debug_pagealloc_enabled()) { 623 vunmap_page_range(start, end); 624 flush_tlb_kernel_range(start, end); 625 } 626 } 627 628 /* 629 * lazy_max_pages is the maximum amount of virtual address space we gather up 630 * before attempting to purge with a TLB flush. 631 * 632 * There is a tradeoff here: a larger number will cover more kernel page tables 633 * and take slightly longer to purge, but it will linearly reduce the number of 634 * global TLB flushes that must be performed. It would seem natural to scale 635 * this number up linearly with the number of CPUs (because vmapping activity 636 * could also scale linearly with the number of CPUs), however it is likely 637 * that in practice, workloads might be constrained in other ways that mean 638 * vmap activity will not scale linearly with CPUs. Also, I want to be 639 * conservative and not introduce a big latency on huge systems, so go with 640 * a less aggressive log scale. It will still be an improvement over the old 641 * code, and it will be simple to change the scale factor if we find that it 642 * becomes a problem on bigger systems. 643 */ 644 static unsigned long lazy_max_pages(void) 645 { 646 unsigned int log; 647 648 log = fls(num_online_cpus()); 649 650 return log * (32UL * 1024 * 1024 / PAGE_SIZE); 651 } 652 653 static atomic_t vmap_lazy_nr = ATOMIC_INIT(0); 654 655 /* 656 * Serialize vmap purging. There is no actual criticial section protected 657 * by this look, but we want to avoid concurrent calls for performance 658 * reasons and to make the pcpu_get_vm_areas more deterministic. 659 */ 660 static DEFINE_MUTEX(vmap_purge_lock); 661 662 /* for per-CPU blocks */ 663 static void purge_fragmented_blocks_allcpus(void); 664 665 /* 666 * called before a call to iounmap() if the caller wants vm_area_struct's 667 * immediately freed. 668 */ 669 void set_iounmap_nonlazy(void) 670 { 671 atomic_set(&vmap_lazy_nr, lazy_max_pages()+1); 672 } 673 674 /* 675 * Purges all lazily-freed vmap areas. 676 */ 677 static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) 678 { 679 struct llist_node *valist; 680 struct vmap_area *va; 681 struct vmap_area *n_va; 682 bool do_free = false; 683 684 lockdep_assert_held(&vmap_purge_lock); 685 686 valist = llist_del_all(&vmap_purge_list); 687 llist_for_each_entry(va, valist, purge_list) { 688 if (va->va_start < start) 689 start = va->va_start; 690 if (va->va_end > end) 691 end = va->va_end; 692 do_free = true; 693 } 694 695 if (!do_free) 696 return false; 697 698 flush_tlb_kernel_range(start, end); 699 700 spin_lock(&vmap_area_lock); 701 llist_for_each_entry_safe(va, n_va, valist, purge_list) { 702 int nr = (va->va_end - va->va_start) >> PAGE_SHIFT; 703 704 __free_vmap_area(va); 705 atomic_sub(nr, &vmap_lazy_nr); 706 cond_resched_lock(&vmap_area_lock); 707 } 708 spin_unlock(&vmap_area_lock); 709 return true; 710 } 711 712 /* 713 * Kick off a purge of the outstanding lazy areas. Don't bother if somebody 714 * is already purging. 715 */ 716 static void try_purge_vmap_area_lazy(void) 717 { 718 if (mutex_trylock(&vmap_purge_lock)) { 719 __purge_vmap_area_lazy(ULONG_MAX, 0); 720 mutex_unlock(&vmap_purge_lock); 721 } 722 } 723 724 /* 725 * Kick off a purge of the outstanding lazy areas. 726 */ 727 static void purge_vmap_area_lazy(void) 728 { 729 mutex_lock(&vmap_purge_lock); 730 purge_fragmented_blocks_allcpus(); 731 __purge_vmap_area_lazy(ULONG_MAX, 0); 732 mutex_unlock(&vmap_purge_lock); 733 } 734 735 /* 736 * Free a vmap area, caller ensuring that the area has been unmapped 737 * and flush_cache_vunmap had been called for the correct range 738 * previously. 739 */ 740 static void free_vmap_area_noflush(struct vmap_area *va) 741 { 742 int nr_lazy; 743 744 nr_lazy = atomic_add_return((va->va_end - va->va_start) >> PAGE_SHIFT, 745 &vmap_lazy_nr); 746 747 /* After this point, we may free va at any time */ 748 llist_add(&va->purge_list, &vmap_purge_list); 749 750 if (unlikely(nr_lazy > lazy_max_pages())) 751 try_purge_vmap_area_lazy(); 752 } 753 754 /* 755 * Free and unmap a vmap area 756 */ 757 static void free_unmap_vmap_area(struct vmap_area *va) 758 { 759 flush_cache_vunmap(va->va_start, va->va_end); 760 unmap_vmap_area(va); 761 free_vmap_area_noflush(va); 762 } 763 764 static struct vmap_area *find_vmap_area(unsigned long addr) 765 { 766 struct vmap_area *va; 767 768 spin_lock(&vmap_area_lock); 769 va = __find_vmap_area(addr); 770 spin_unlock(&vmap_area_lock); 771 772 return va; 773 } 774 775 /*** Per cpu kva allocator ***/ 776 777 /* 778 * vmap space is limited especially on 32 bit architectures. Ensure there is 779 * room for at least 16 percpu vmap blocks per CPU. 780 */ 781 /* 782 * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able 783 * to #define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START). Guess 784 * instead (we just need a rough idea) 785 */ 786 #if BITS_PER_LONG == 32 787 #define VMALLOC_SPACE (128UL*1024*1024) 788 #else 789 #define VMALLOC_SPACE (128UL*1024*1024*1024) 790 #endif 791 792 #define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE) 793 #define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */ 794 #define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */ 795 #define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2) 796 #define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */ 797 #define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */ 798 #define VMAP_BBMAP_BITS \ 799 VMAP_MIN(VMAP_BBMAP_BITS_MAX, \ 800 VMAP_MAX(VMAP_BBMAP_BITS_MIN, \ 801 VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16)) 802 803 #define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE) 804 805 static bool vmap_initialized __read_mostly = false; 806 807 struct vmap_block_queue { 808 spinlock_t lock; 809 struct list_head free; 810 }; 811 812 struct vmap_block { 813 spinlock_t lock; 814 struct vmap_area *va; 815 unsigned long free, dirty; 816 unsigned long dirty_min, dirty_max; /*< dirty range */ 817 struct list_head free_list; 818 struct rcu_head rcu_head; 819 struct list_head purge; 820 }; 821 822 /* Queue of free and dirty vmap blocks, for allocation and flushing purposes */ 823 static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue); 824 825 /* 826 * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block 827 * in the free path. Could get rid of this if we change the API to return a 828 * "cookie" from alloc, to be passed to free. But no big deal yet. 829 */ 830 static DEFINE_SPINLOCK(vmap_block_tree_lock); 831 static RADIX_TREE(vmap_block_tree, GFP_ATOMIC); 832 833 /* 834 * We should probably have a fallback mechanism to allocate virtual memory 835 * out of partially filled vmap blocks. However vmap block sizing should be 836 * fairly reasonable according to the vmalloc size, so it shouldn't be a 837 * big problem. 838 */ 839 840 static unsigned long addr_to_vb_idx(unsigned long addr) 841 { 842 addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1); 843 addr /= VMAP_BLOCK_SIZE; 844 return addr; 845 } 846 847 static void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off) 848 { 849 unsigned long addr; 850 851 addr = va_start + (pages_off << PAGE_SHIFT); 852 BUG_ON(addr_to_vb_idx(addr) != addr_to_vb_idx(va_start)); 853 return (void *)addr; 854 } 855 856 /** 857 * new_vmap_block - allocates new vmap_block and occupies 2^order pages in this 858 * block. Of course pages number can't exceed VMAP_BBMAP_BITS 859 * @order: how many 2^order pages should be occupied in newly allocated block 860 * @gfp_mask: flags for the page level allocator 861 * 862 * Returns: virtual address in a newly allocated block or ERR_PTR(-errno) 863 */ 864 static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) 865 { 866 struct vmap_block_queue *vbq; 867 struct vmap_block *vb; 868 struct vmap_area *va; 869 unsigned long vb_idx; 870 int node, err; 871 void *vaddr; 872 873 node = numa_node_id(); 874 875 vb = kmalloc_node(sizeof(struct vmap_block), 876 gfp_mask & GFP_RECLAIM_MASK, node); 877 if (unlikely(!vb)) 878 return ERR_PTR(-ENOMEM); 879 880 va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE, 881 VMALLOC_START, VMALLOC_END, 882 node, gfp_mask); 883 if (IS_ERR(va)) { 884 kfree(vb); 885 return ERR_CAST(va); 886 } 887 888 err = radix_tree_preload(gfp_mask); 889 if (unlikely(err)) { 890 kfree(vb); 891 free_vmap_area(va); 892 return ERR_PTR(err); 893 } 894 895 vaddr = vmap_block_vaddr(va->va_start, 0); 896 spin_lock_init(&vb->lock); 897 vb->va = va; 898 /* At least something should be left free */ 899 BUG_ON(VMAP_BBMAP_BITS <= (1UL << order)); 900 vb->free = VMAP_BBMAP_BITS - (1UL << order); 901 vb->dirty = 0; 902 vb->dirty_min = VMAP_BBMAP_BITS; 903 vb->dirty_max = 0; 904 INIT_LIST_HEAD(&vb->free_list); 905 906 vb_idx = addr_to_vb_idx(va->va_start); 907 spin_lock(&vmap_block_tree_lock); 908 err = radix_tree_insert(&vmap_block_tree, vb_idx, vb); 909 spin_unlock(&vmap_block_tree_lock); 910 BUG_ON(err); 911 radix_tree_preload_end(); 912 913 vbq = &get_cpu_var(vmap_block_queue); 914 spin_lock(&vbq->lock); 915 list_add_tail_rcu(&vb->free_list, &vbq->free); 916 spin_unlock(&vbq->lock); 917 put_cpu_var(vmap_block_queue); 918 919 return vaddr; 920 } 921 922 static void free_vmap_block(struct vmap_block *vb) 923 { 924 struct vmap_block *tmp; 925 unsigned long vb_idx; 926 927 vb_idx = addr_to_vb_idx(vb->va->va_start); 928 spin_lock(&vmap_block_tree_lock); 929 tmp = radix_tree_delete(&vmap_block_tree, vb_idx); 930 spin_unlock(&vmap_block_tree_lock); 931 BUG_ON(tmp != vb); 932 933 free_vmap_area_noflush(vb->va); 934 kfree_rcu(vb, rcu_head); 935 } 936 937 static void purge_fragmented_blocks(int cpu) 938 { 939 LIST_HEAD(purge); 940 struct vmap_block *vb; 941 struct vmap_block *n_vb; 942 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu); 943 944 rcu_read_lock(); 945 list_for_each_entry_rcu(vb, &vbq->free, free_list) { 946 947 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS)) 948 continue; 949 950 spin_lock(&vb->lock); 951 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) { 952 vb->free = 0; /* prevent further allocs after releasing lock */ 953 vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */ 954 vb->dirty_min = 0; 955 vb->dirty_max = VMAP_BBMAP_BITS; 956 spin_lock(&vbq->lock); 957 list_del_rcu(&vb->free_list); 958 spin_unlock(&vbq->lock); 959 spin_unlock(&vb->lock); 960 list_add_tail(&vb->purge, &purge); 961 } else 962 spin_unlock(&vb->lock); 963 } 964 rcu_read_unlock(); 965 966 list_for_each_entry_safe(vb, n_vb, &purge, purge) { 967 list_del(&vb->purge); 968 free_vmap_block(vb); 969 } 970 } 971 972 static void purge_fragmented_blocks_allcpus(void) 973 { 974 int cpu; 975 976 for_each_possible_cpu(cpu) 977 purge_fragmented_blocks(cpu); 978 } 979 980 static void *vb_alloc(unsigned long size, gfp_t gfp_mask) 981 { 982 struct vmap_block_queue *vbq; 983 struct vmap_block *vb; 984 void *vaddr = NULL; 985 unsigned int order; 986 987 BUG_ON(offset_in_page(size)); 988 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC); 989 if (WARN_ON(size == 0)) { 990 /* 991 * Allocating 0 bytes isn't what caller wants since 992 * get_order(0) returns funny result. Just warn and terminate 993 * early. 994 */ 995 return NULL; 996 } 997 order = get_order(size); 998 999 rcu_read_lock(); 1000 vbq = &get_cpu_var(vmap_block_queue); 1001 list_for_each_entry_rcu(vb, &vbq->free, free_list) { 1002 unsigned long pages_off; 1003 1004 spin_lock(&vb->lock); 1005 if (vb->free < (1UL << order)) { 1006 spin_unlock(&vb->lock); 1007 continue; 1008 } 1009 1010 pages_off = VMAP_BBMAP_BITS - vb->free; 1011 vaddr = vmap_block_vaddr(vb->va->va_start, pages_off); 1012 vb->free -= 1UL << order; 1013 if (vb->free == 0) { 1014 spin_lock(&vbq->lock); 1015 list_del_rcu(&vb->free_list); 1016 spin_unlock(&vbq->lock); 1017 } 1018 1019 spin_unlock(&vb->lock); 1020 break; 1021 } 1022 1023 put_cpu_var(vmap_block_queue); 1024 rcu_read_unlock(); 1025 1026 /* Allocate new block if nothing was found */ 1027 if (!vaddr) 1028 vaddr = new_vmap_block(order, gfp_mask); 1029 1030 return vaddr; 1031 } 1032 1033 static void vb_free(const void *addr, unsigned long size) 1034 { 1035 unsigned long offset; 1036 unsigned long vb_idx; 1037 unsigned int order; 1038 struct vmap_block *vb; 1039 1040 BUG_ON(offset_in_page(size)); 1041 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC); 1042 1043 flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size); 1044 1045 order = get_order(size); 1046 1047 offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1); 1048 offset >>= PAGE_SHIFT; 1049 1050 vb_idx = addr_to_vb_idx((unsigned long)addr); 1051 rcu_read_lock(); 1052 vb = radix_tree_lookup(&vmap_block_tree, vb_idx); 1053 rcu_read_unlock(); 1054 BUG_ON(!vb); 1055 1056 vunmap_page_range((unsigned long)addr, (unsigned long)addr + size); 1057 1058 spin_lock(&vb->lock); 1059 1060 /* Expand dirty range */ 1061 vb->dirty_min = min(vb->dirty_min, offset); 1062 vb->dirty_max = max(vb->dirty_max, offset + (1UL << order)); 1063 1064 vb->dirty += 1UL << order; 1065 if (vb->dirty == VMAP_BBMAP_BITS) { 1066 BUG_ON(vb->free); 1067 spin_unlock(&vb->lock); 1068 free_vmap_block(vb); 1069 } else 1070 spin_unlock(&vb->lock); 1071 } 1072 1073 /** 1074 * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer 1075 * 1076 * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily 1077 * to amortize TLB flushing overheads. What this means is that any page you 1078 * have now, may, in a former life, have been mapped into kernel virtual 1079 * address by the vmap layer and so there might be some CPUs with TLB entries 1080 * still referencing that page (additional to the regular 1:1 kernel mapping). 1081 * 1082 * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can 1083 * be sure that none of the pages we have control over will have any aliases 1084 * from the vmap layer. 1085 */ 1086 void vm_unmap_aliases(void) 1087 { 1088 unsigned long start = ULONG_MAX, end = 0; 1089 int cpu; 1090 int flush = 0; 1091 1092 if (unlikely(!vmap_initialized)) 1093 return; 1094 1095 might_sleep(); 1096 1097 for_each_possible_cpu(cpu) { 1098 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu); 1099 struct vmap_block *vb; 1100 1101 rcu_read_lock(); 1102 list_for_each_entry_rcu(vb, &vbq->free, free_list) { 1103 spin_lock(&vb->lock); 1104 if (vb->dirty) { 1105 unsigned long va_start = vb->va->va_start; 1106 unsigned long s, e; 1107 1108 s = va_start + (vb->dirty_min << PAGE_SHIFT); 1109 e = va_start + (vb->dirty_max << PAGE_SHIFT); 1110 1111 start = min(s, start); 1112 end = max(e, end); 1113 1114 flush = 1; 1115 } 1116 spin_unlock(&vb->lock); 1117 } 1118 rcu_read_unlock(); 1119 } 1120 1121 mutex_lock(&vmap_purge_lock); 1122 purge_fragmented_blocks_allcpus(); 1123 if (!__purge_vmap_area_lazy(start, end) && flush) 1124 flush_tlb_kernel_range(start, end); 1125 mutex_unlock(&vmap_purge_lock); 1126 } 1127 EXPORT_SYMBOL_GPL(vm_unmap_aliases); 1128 1129 /** 1130 * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram 1131 * @mem: the pointer returned by vm_map_ram 1132 * @count: the count passed to that vm_map_ram call (cannot unmap partial) 1133 */ 1134 void vm_unmap_ram(const void *mem, unsigned int count) 1135 { 1136 unsigned long size = (unsigned long)count << PAGE_SHIFT; 1137 unsigned long addr = (unsigned long)mem; 1138 struct vmap_area *va; 1139 1140 might_sleep(); 1141 BUG_ON(!addr); 1142 BUG_ON(addr < VMALLOC_START); 1143 BUG_ON(addr > VMALLOC_END); 1144 BUG_ON(!PAGE_ALIGNED(addr)); 1145 1146 debug_check_no_locks_freed(mem, size); 1147 vmap_debug_free_range(addr, addr+size); 1148 1149 if (likely(count <= VMAP_MAX_ALLOC)) { 1150 vb_free(mem, size); 1151 return; 1152 } 1153 1154 va = find_vmap_area(addr); 1155 BUG_ON(!va); 1156 free_unmap_vmap_area(va); 1157 } 1158 EXPORT_SYMBOL(vm_unmap_ram); 1159 1160 /** 1161 * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space) 1162 * @pages: an array of pointers to the pages to be mapped 1163 * @count: number of pages 1164 * @node: prefer to allocate data structures on this node 1165 * @prot: memory protection to use. PAGE_KERNEL for regular RAM 1166 * 1167 * If you use this function for less than VMAP_MAX_ALLOC pages, it could be 1168 * faster than vmap so it's good. But if you mix long-life and short-life 1169 * objects with vm_map_ram(), it could consume lots of address space through 1170 * fragmentation (especially on a 32bit machine). You could see failures in 1171 * the end. Please use this function for short-lived objects. 1172 * 1173 * Returns: a pointer to the address that has been mapped, or %NULL on failure 1174 */ 1175 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot) 1176 { 1177 unsigned long size = (unsigned long)count << PAGE_SHIFT; 1178 unsigned long addr; 1179 void *mem; 1180 1181 if (likely(count <= VMAP_MAX_ALLOC)) { 1182 mem = vb_alloc(size, GFP_KERNEL); 1183 if (IS_ERR(mem)) 1184 return NULL; 1185 addr = (unsigned long)mem; 1186 } else { 1187 struct vmap_area *va; 1188 va = alloc_vmap_area(size, PAGE_SIZE, 1189 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL); 1190 if (IS_ERR(va)) 1191 return NULL; 1192 1193 addr = va->va_start; 1194 mem = (void *)addr; 1195 } 1196 if (vmap_page_range(addr, addr + size, prot, pages) < 0) { 1197 vm_unmap_ram(mem, count); 1198 return NULL; 1199 } 1200 return mem; 1201 } 1202 EXPORT_SYMBOL(vm_map_ram); 1203 1204 static struct vm_struct *vmlist __initdata; 1205 /** 1206 * vm_area_add_early - add vmap area early during boot 1207 * @vm: vm_struct to add 1208 * 1209 * This function is used to add fixed kernel vm area to vmlist before 1210 * vmalloc_init() is called. @vm->addr, @vm->size, and @vm->flags 1211 * should contain proper values and the other fields should be zero. 1212 * 1213 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING. 1214 */ 1215 void __init vm_area_add_early(struct vm_struct *vm) 1216 { 1217 struct vm_struct *tmp, **p; 1218 1219 BUG_ON(vmap_initialized); 1220 for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) { 1221 if (tmp->addr >= vm->addr) { 1222 BUG_ON(tmp->addr < vm->addr + vm->size); 1223 break; 1224 } else 1225 BUG_ON(tmp->addr + tmp->size > vm->addr); 1226 } 1227 vm->next = *p; 1228 *p = vm; 1229 } 1230 1231 /** 1232 * vm_area_register_early - register vmap area early during boot 1233 * @vm: vm_struct to register 1234 * @align: requested alignment 1235 * 1236 * This function is used to register kernel vm area before 1237 * vmalloc_init() is called. @vm->size and @vm->flags should contain 1238 * proper values on entry and other fields should be zero. On return, 1239 * vm->addr contains the allocated address. 1240 * 1241 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING. 1242 */ 1243 void __init vm_area_register_early(struct vm_struct *vm, size_t align) 1244 { 1245 static size_t vm_init_off __initdata; 1246 unsigned long addr; 1247 1248 addr = ALIGN(VMALLOC_START + vm_init_off, align); 1249 vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START; 1250 1251 vm->addr = (void *)addr; 1252 1253 vm_area_add_early(vm); 1254 } 1255 1256 void __init vmalloc_init(void) 1257 { 1258 struct vmap_area *va; 1259 struct vm_struct *tmp; 1260 int i; 1261 1262 for_each_possible_cpu(i) { 1263 struct vmap_block_queue *vbq; 1264 struct vfree_deferred *p; 1265 1266 vbq = &per_cpu(vmap_block_queue, i); 1267 spin_lock_init(&vbq->lock); 1268 INIT_LIST_HEAD(&vbq->free); 1269 p = &per_cpu(vfree_deferred, i); 1270 init_llist_head(&p->list); 1271 INIT_WORK(&p->wq, free_work); 1272 } 1273 1274 /* Import existing vmlist entries. */ 1275 for (tmp = vmlist; tmp; tmp = tmp->next) { 1276 va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT); 1277 va->flags = VM_VM_AREA; 1278 va->va_start = (unsigned long)tmp->addr; 1279 va->va_end = va->va_start + tmp->size; 1280 va->vm = tmp; 1281 __insert_vmap_area(va); 1282 } 1283 1284 vmap_area_pcpu_hole = VMALLOC_END; 1285 1286 vmap_initialized = true; 1287 } 1288 1289 /** 1290 * map_kernel_range_noflush - map kernel VM area with the specified pages 1291 * @addr: start of the VM area to map 1292 * @size: size of the VM area to map 1293 * @prot: page protection flags to use 1294 * @pages: pages to map 1295 * 1296 * Map PFN_UP(@size) pages at @addr. The VM area @addr and @size 1297 * specify should have been allocated using get_vm_area() and its 1298 * friends. 1299 * 1300 * NOTE: 1301 * This function does NOT do any cache flushing. The caller is 1302 * responsible for calling flush_cache_vmap() on to-be-mapped areas 1303 * before calling this function. 1304 * 1305 * RETURNS: 1306 * The number of pages mapped on success, -errno on failure. 1307 */ 1308 int map_kernel_range_noflush(unsigned long addr, unsigned long size, 1309 pgprot_t prot, struct page **pages) 1310 { 1311 return vmap_page_range_noflush(addr, addr + size, prot, pages); 1312 } 1313 1314 /** 1315 * unmap_kernel_range_noflush - unmap kernel VM area 1316 * @addr: start of the VM area to unmap 1317 * @size: size of the VM area to unmap 1318 * 1319 * Unmap PFN_UP(@size) pages at @addr. The VM area @addr and @size 1320 * specify should have been allocated using get_vm_area() and its 1321 * friends. 1322 * 1323 * NOTE: 1324 * This function does NOT do any cache flushing. The caller is 1325 * responsible for calling flush_cache_vunmap() on to-be-mapped areas 1326 * before calling this function and flush_tlb_kernel_range() after. 1327 */ 1328 void unmap_kernel_range_noflush(unsigned long addr, unsigned long size) 1329 { 1330 vunmap_page_range(addr, addr + size); 1331 } 1332 EXPORT_SYMBOL_GPL(unmap_kernel_range_noflush); 1333 1334 /** 1335 * unmap_kernel_range - unmap kernel VM area and flush cache and TLB 1336 * @addr: start of the VM area to unmap 1337 * @size: size of the VM area to unmap 1338 * 1339 * Similar to unmap_kernel_range_noflush() but flushes vcache before 1340 * the unmapping and tlb after. 1341 */ 1342 void unmap_kernel_range(unsigned long addr, unsigned long size) 1343 { 1344 unsigned long end = addr + size; 1345 1346 flush_cache_vunmap(addr, end); 1347 vunmap_page_range(addr, end); 1348 flush_tlb_kernel_range(addr, end); 1349 } 1350 EXPORT_SYMBOL_GPL(unmap_kernel_range); 1351 1352 int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page **pages) 1353 { 1354 unsigned long addr = (unsigned long)area->addr; 1355 unsigned long end = addr + get_vm_area_size(area); 1356 int err; 1357 1358 err = vmap_page_range(addr, end, prot, pages); 1359 1360 return err > 0 ? 0 : err; 1361 } 1362 EXPORT_SYMBOL_GPL(map_vm_area); 1363 1364 static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, 1365 unsigned long flags, const void *caller) 1366 { 1367 spin_lock(&vmap_area_lock); 1368 vm->flags = flags; 1369 vm->addr = (void *)va->va_start; 1370 vm->size = va->va_end - va->va_start; 1371 vm->caller = caller; 1372 va->vm = vm; 1373 va->flags |= VM_VM_AREA; 1374 spin_unlock(&vmap_area_lock); 1375 } 1376 1377 static void clear_vm_uninitialized_flag(struct vm_struct *vm) 1378 { 1379 /* 1380 * Before removing VM_UNINITIALIZED, 1381 * we should make sure that vm has proper values. 1382 * Pair with smp_rmb() in show_numa_info(). 1383 */ 1384 smp_wmb(); 1385 vm->flags &= ~VM_UNINITIALIZED; 1386 } 1387 1388 static struct vm_struct *__get_vm_area_node(unsigned long size, 1389 unsigned long align, unsigned long flags, unsigned long start, 1390 unsigned long end, int node, gfp_t gfp_mask, const void *caller) 1391 { 1392 struct vmap_area *va; 1393 struct vm_struct *area; 1394 1395 BUG_ON(in_interrupt()); 1396 size = PAGE_ALIGN(size); 1397 if (unlikely(!size)) 1398 return NULL; 1399 1400 if (flags & VM_IOREMAP) 1401 align = 1ul << clamp_t(int, get_count_order_long(size), 1402 PAGE_SHIFT, IOREMAP_MAX_ORDER); 1403 1404 area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node); 1405 if (unlikely(!area)) 1406 return NULL; 1407 1408 if (!(flags & VM_NO_GUARD)) 1409 size += PAGE_SIZE; 1410 1411 va = alloc_vmap_area(size, align, start, end, node, gfp_mask); 1412 if (IS_ERR(va)) { 1413 kfree(area); 1414 return NULL; 1415 } 1416 1417 setup_vmalloc_vm(area, va, flags, caller); 1418 1419 return area; 1420 } 1421 1422 struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, 1423 unsigned long start, unsigned long end) 1424 { 1425 return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE, 1426 GFP_KERNEL, __builtin_return_address(0)); 1427 } 1428 EXPORT_SYMBOL_GPL(__get_vm_area); 1429 1430 struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags, 1431 unsigned long start, unsigned long end, 1432 const void *caller) 1433 { 1434 return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE, 1435 GFP_KERNEL, caller); 1436 } 1437 1438 /** 1439 * get_vm_area - reserve a contiguous kernel virtual area 1440 * @size: size of the area 1441 * @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC 1442 * 1443 * Search an area of @size in the kernel virtual mapping area, 1444 * and reserved it for out purposes. Returns the area descriptor 1445 * on success or %NULL on failure. 1446 */ 1447 struct vm_struct *get_vm_area(unsigned long size, unsigned long flags) 1448 { 1449 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END, 1450 NUMA_NO_NODE, GFP_KERNEL, 1451 __builtin_return_address(0)); 1452 } 1453 1454 struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags, 1455 const void *caller) 1456 { 1457 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END, 1458 NUMA_NO_NODE, GFP_KERNEL, caller); 1459 } 1460 1461 /** 1462 * find_vm_area - find a continuous kernel virtual area 1463 * @addr: base address 1464 * 1465 * Search for the kernel VM area starting at @addr, and return it. 1466 * It is up to the caller to do all required locking to keep the returned 1467 * pointer valid. 1468 */ 1469 struct vm_struct *find_vm_area(const void *addr) 1470 { 1471 struct vmap_area *va; 1472 1473 va = find_vmap_area((unsigned long)addr); 1474 if (va && va->flags & VM_VM_AREA) 1475 return va->vm; 1476 1477 return NULL; 1478 } 1479 1480 /** 1481 * remove_vm_area - find and remove a continuous kernel virtual area 1482 * @addr: base address 1483 * 1484 * Search for the kernel VM area starting at @addr, and remove it. 1485 * This function returns the found VM area, but using it is NOT safe 1486 * on SMP machines, except for its size or flags. 1487 */ 1488 struct vm_struct *remove_vm_area(const void *addr) 1489 { 1490 struct vmap_area *va; 1491 1492 might_sleep(); 1493 1494 va = find_vmap_area((unsigned long)addr); 1495 if (va && va->flags & VM_VM_AREA) { 1496 struct vm_struct *vm = va->vm; 1497 1498 spin_lock(&vmap_area_lock); 1499 va->vm = NULL; 1500 va->flags &= ~VM_VM_AREA; 1501 va->flags |= VM_LAZY_FREE; 1502 spin_unlock(&vmap_area_lock); 1503 1504 vmap_debug_free_range(va->va_start, va->va_end); 1505 kasan_free_shadow(vm); 1506 free_unmap_vmap_area(va); 1507 1508 return vm; 1509 } 1510 return NULL; 1511 } 1512 1513 static void __vunmap(const void *addr, int deallocate_pages) 1514 { 1515 struct vm_struct *area; 1516 1517 if (!addr) 1518 return; 1519 1520 if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n", 1521 addr)) 1522 return; 1523 1524 area = remove_vm_area(addr); 1525 if (unlikely(!area)) { 1526 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n", 1527 addr); 1528 return; 1529 } 1530 1531 debug_check_no_locks_freed(addr, get_vm_area_size(area)); 1532 debug_check_no_obj_freed(addr, get_vm_area_size(area)); 1533 1534 if (deallocate_pages) { 1535 int i; 1536 1537 for (i = 0; i < area->nr_pages; i++) { 1538 struct page *page = area->pages[i]; 1539 1540 BUG_ON(!page); 1541 __free_pages(page, 0); 1542 } 1543 1544 kvfree(area->pages); 1545 } 1546 1547 kfree(area); 1548 return; 1549 } 1550 1551 static inline void __vfree_deferred(const void *addr) 1552 { 1553 /* 1554 * Use raw_cpu_ptr() because this can be called from preemptible 1555 * context. Preemption is absolutely fine here, because the llist_add() 1556 * implementation is lockless, so it works even if we are adding to 1557 * nother cpu's list. schedule_work() should be fine with this too. 1558 */ 1559 struct vfree_deferred *p = raw_cpu_ptr(&vfree_deferred); 1560 1561 if (llist_add((struct llist_node *)addr, &p->list)) 1562 schedule_work(&p->wq); 1563 } 1564 1565 /** 1566 * vfree_atomic - release memory allocated by vmalloc() 1567 * @addr: memory base address 1568 * 1569 * This one is just like vfree() but can be called in any atomic context 1570 * except NMIs. 1571 */ 1572 void vfree_atomic(const void *addr) 1573 { 1574 BUG_ON(in_nmi()); 1575 1576 kmemleak_free(addr); 1577 1578 if (!addr) 1579 return; 1580 __vfree_deferred(addr); 1581 } 1582 1583 /** 1584 * vfree - release memory allocated by vmalloc() 1585 * @addr: memory base address 1586 * 1587 * Free the virtually continuous memory area starting at @addr, as 1588 * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is 1589 * NULL, no operation is performed. 1590 * 1591 * Must not be called in NMI context (strictly speaking, only if we don't 1592 * have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling 1593 * conventions for vfree() arch-depenedent would be a really bad idea) 1594 * 1595 * NOTE: assumes that the object at @addr has a size >= sizeof(llist_node) 1596 */ 1597 void vfree(const void *addr) 1598 { 1599 BUG_ON(in_nmi()); 1600 1601 kmemleak_free(addr); 1602 1603 if (!addr) 1604 return; 1605 if (unlikely(in_interrupt())) 1606 __vfree_deferred(addr); 1607 else 1608 __vunmap(addr, 1); 1609 } 1610 EXPORT_SYMBOL(vfree); 1611 1612 /** 1613 * vunmap - release virtual mapping obtained by vmap() 1614 * @addr: memory base address 1615 * 1616 * Free the virtually contiguous memory area starting at @addr, 1617 * which was created from the page array passed to vmap(). 1618 * 1619 * Must not be called in interrupt context. 1620 */ 1621 void vunmap(const void *addr) 1622 { 1623 BUG_ON(in_interrupt()); 1624 might_sleep(); 1625 if (addr) 1626 __vunmap(addr, 0); 1627 } 1628 EXPORT_SYMBOL(vunmap); 1629 1630 /** 1631 * vmap - map an array of pages into virtually contiguous space 1632 * @pages: array of page pointers 1633 * @count: number of pages to map 1634 * @flags: vm_area->flags 1635 * @prot: page protection for the mapping 1636 * 1637 * Maps @count pages from @pages into contiguous kernel virtual 1638 * space. 1639 */ 1640 void *vmap(struct page **pages, unsigned int count, 1641 unsigned long flags, pgprot_t prot) 1642 { 1643 struct vm_struct *area; 1644 unsigned long size; /* In bytes */ 1645 1646 might_sleep(); 1647 1648 if (count > totalram_pages) 1649 return NULL; 1650 1651 size = (unsigned long)count << PAGE_SHIFT; 1652 area = get_vm_area_caller(size, flags, __builtin_return_address(0)); 1653 if (!area) 1654 return NULL; 1655 1656 if (map_vm_area(area, prot, pages)) { 1657 vunmap(area->addr); 1658 return NULL; 1659 } 1660 1661 return area->addr; 1662 } 1663 EXPORT_SYMBOL(vmap); 1664 1665 static void *__vmalloc_node(unsigned long size, unsigned long align, 1666 gfp_t gfp_mask, pgprot_t prot, 1667 int node, const void *caller); 1668 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, 1669 pgprot_t prot, int node) 1670 { 1671 struct page **pages; 1672 unsigned int nr_pages, array_size, i; 1673 const gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; 1674 const gfp_t alloc_mask = gfp_mask | __GFP_HIGHMEM | __GFP_NOWARN; 1675 1676 nr_pages = get_vm_area_size(area) >> PAGE_SHIFT; 1677 array_size = (nr_pages * sizeof(struct page *)); 1678 1679 area->nr_pages = nr_pages; 1680 /* Please note that the recursion is strictly bounded. */ 1681 if (array_size > PAGE_SIZE) { 1682 pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM, 1683 PAGE_KERNEL, node, area->caller); 1684 } else { 1685 pages = kmalloc_node(array_size, nested_gfp, node); 1686 } 1687 area->pages = pages; 1688 if (!area->pages) { 1689 remove_vm_area(area->addr); 1690 kfree(area); 1691 return NULL; 1692 } 1693 1694 for (i = 0; i < area->nr_pages; i++) { 1695 struct page *page; 1696 1697 if (fatal_signal_pending(current)) { 1698 area->nr_pages = i; 1699 goto fail_no_warn; 1700 } 1701 1702 if (node == NUMA_NO_NODE) 1703 page = alloc_page(alloc_mask); 1704 else 1705 page = alloc_pages_node(node, alloc_mask, 0); 1706 1707 if (unlikely(!page)) { 1708 /* Successfully allocated i pages, free them in __vunmap() */ 1709 area->nr_pages = i; 1710 goto fail; 1711 } 1712 area->pages[i] = page; 1713 if (gfpflags_allow_blocking(gfp_mask)) 1714 cond_resched(); 1715 } 1716 1717 if (map_vm_area(area, prot, pages)) 1718 goto fail; 1719 return area->addr; 1720 1721 fail: 1722 warn_alloc(gfp_mask, NULL, 1723 "vmalloc: allocation failure, allocated %ld of %ld bytes", 1724 (area->nr_pages*PAGE_SIZE), area->size); 1725 fail_no_warn: 1726 vfree(area->addr); 1727 return NULL; 1728 } 1729 1730 /** 1731 * __vmalloc_node_range - allocate virtually contiguous memory 1732 * @size: allocation size 1733 * @align: desired alignment 1734 * @start: vm area range start 1735 * @end: vm area range end 1736 * @gfp_mask: flags for the page level allocator 1737 * @prot: protection mask for the allocated pages 1738 * @vm_flags: additional vm area flags (e.g. %VM_NO_GUARD) 1739 * @node: node to use for allocation or NUMA_NO_NODE 1740 * @caller: caller's return address 1741 * 1742 * Allocate enough pages to cover @size from the page level 1743 * allocator with @gfp_mask flags. Map them into contiguous 1744 * kernel virtual space, using a pagetable protection of @prot. 1745 */ 1746 void *__vmalloc_node_range(unsigned long size, unsigned long align, 1747 unsigned long start, unsigned long end, gfp_t gfp_mask, 1748 pgprot_t prot, unsigned long vm_flags, int node, 1749 const void *caller) 1750 { 1751 struct vm_struct *area; 1752 void *addr; 1753 unsigned long real_size = size; 1754 1755 size = PAGE_ALIGN(size); 1756 if (!size || (size >> PAGE_SHIFT) > totalram_pages) 1757 goto fail; 1758 1759 area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED | 1760 vm_flags, start, end, node, gfp_mask, caller); 1761 if (!area) 1762 goto fail; 1763 1764 addr = __vmalloc_area_node(area, gfp_mask, prot, node); 1765 if (!addr) 1766 return NULL; 1767 1768 /* 1769 * In this function, newly allocated vm_struct has VM_UNINITIALIZED 1770 * flag. It means that vm_struct is not fully initialized. 1771 * Now, it is fully initialized, so remove this flag here. 1772 */ 1773 clear_vm_uninitialized_flag(area); 1774 1775 kmemleak_vmalloc(area, size, gfp_mask); 1776 1777 return addr; 1778 1779 fail: 1780 warn_alloc(gfp_mask, NULL, 1781 "vmalloc: allocation failure: %lu bytes", real_size); 1782 return NULL; 1783 } 1784 1785 /** 1786 * __vmalloc_node - allocate virtually contiguous memory 1787 * @size: allocation size 1788 * @align: desired alignment 1789 * @gfp_mask: flags for the page level allocator 1790 * @prot: protection mask for the allocated pages 1791 * @node: node to use for allocation or NUMA_NO_NODE 1792 * @caller: caller's return address 1793 * 1794 * Allocate enough pages to cover @size from the page level 1795 * allocator with @gfp_mask flags. Map them into contiguous 1796 * kernel virtual space, using a pagetable protection of @prot. 1797 * 1798 * Reclaim modifiers in @gfp_mask - __GFP_NORETRY, __GFP_RETRY_MAYFAIL 1799 * and __GFP_NOFAIL are not supported 1800 * 1801 * Any use of gfp flags outside of GFP_KERNEL should be consulted 1802 * with mm people. 1803 * 1804 */ 1805 static void *__vmalloc_node(unsigned long size, unsigned long align, 1806 gfp_t gfp_mask, pgprot_t prot, 1807 int node, const void *caller) 1808 { 1809 return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END, 1810 gfp_mask, prot, 0, node, caller); 1811 } 1812 1813 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) 1814 { 1815 return __vmalloc_node(size, 1, gfp_mask, prot, NUMA_NO_NODE, 1816 __builtin_return_address(0)); 1817 } 1818 EXPORT_SYMBOL(__vmalloc); 1819 1820 static inline void *__vmalloc_node_flags(unsigned long size, 1821 int node, gfp_t flags) 1822 { 1823 return __vmalloc_node(size, 1, flags, PAGE_KERNEL, 1824 node, __builtin_return_address(0)); 1825 } 1826 1827 1828 void *__vmalloc_node_flags_caller(unsigned long size, int node, gfp_t flags, 1829 void *caller) 1830 { 1831 return __vmalloc_node(size, 1, flags, PAGE_KERNEL, node, caller); 1832 } 1833 1834 /** 1835 * vmalloc - allocate virtually contiguous memory 1836 * @size: allocation size 1837 * Allocate enough pages to cover @size from the page level 1838 * allocator and map them into contiguous kernel virtual space. 1839 * 1840 * For tight control over page level allocator and protection flags 1841 * use __vmalloc() instead. 1842 */ 1843 void *vmalloc(unsigned long size) 1844 { 1845 return __vmalloc_node_flags(size, NUMA_NO_NODE, 1846 GFP_KERNEL); 1847 } 1848 EXPORT_SYMBOL(vmalloc); 1849 1850 /** 1851 * vzalloc - allocate virtually contiguous memory with zero fill 1852 * @size: allocation size 1853 * Allocate enough pages to cover @size from the page level 1854 * allocator and map them into contiguous kernel virtual space. 1855 * The memory allocated is set to zero. 1856 * 1857 * For tight control over page level allocator and protection flags 1858 * use __vmalloc() instead. 1859 */ 1860 void *vzalloc(unsigned long size) 1861 { 1862 return __vmalloc_node_flags(size, NUMA_NO_NODE, 1863 GFP_KERNEL | __GFP_ZERO); 1864 } 1865 EXPORT_SYMBOL(vzalloc); 1866 1867 /** 1868 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace 1869 * @size: allocation size 1870 * 1871 * The resulting memory area is zeroed so it can be mapped to userspace 1872 * without leaking data. 1873 */ 1874 void *vmalloc_user(unsigned long size) 1875 { 1876 struct vm_struct *area; 1877 void *ret; 1878 1879 ret = __vmalloc_node(size, SHMLBA, 1880 GFP_KERNEL | __GFP_ZERO, 1881 PAGE_KERNEL, NUMA_NO_NODE, 1882 __builtin_return_address(0)); 1883 if (ret) { 1884 area = find_vm_area(ret); 1885 area->flags |= VM_USERMAP; 1886 } 1887 return ret; 1888 } 1889 EXPORT_SYMBOL(vmalloc_user); 1890 1891 /** 1892 * vmalloc_node - allocate memory on a specific node 1893 * @size: allocation size 1894 * @node: numa node 1895 * 1896 * Allocate enough pages to cover @size from the page level 1897 * allocator and map them into contiguous kernel virtual space. 1898 * 1899 * For tight control over page level allocator and protection flags 1900 * use __vmalloc() instead. 1901 */ 1902 void *vmalloc_node(unsigned long size, int node) 1903 { 1904 return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL, 1905 node, __builtin_return_address(0)); 1906 } 1907 EXPORT_SYMBOL(vmalloc_node); 1908 1909 /** 1910 * vzalloc_node - allocate memory on a specific node with zero fill 1911 * @size: allocation size 1912 * @node: numa node 1913 * 1914 * Allocate enough pages to cover @size from the page level 1915 * allocator and map them into contiguous kernel virtual space. 1916 * The memory allocated is set to zero. 1917 * 1918 * For tight control over page level allocator and protection flags 1919 * use __vmalloc_node() instead. 1920 */ 1921 void *vzalloc_node(unsigned long size, int node) 1922 { 1923 return __vmalloc_node_flags(size, node, 1924 GFP_KERNEL | __GFP_ZERO); 1925 } 1926 EXPORT_SYMBOL(vzalloc_node); 1927 1928 #ifndef PAGE_KERNEL_EXEC 1929 # define PAGE_KERNEL_EXEC PAGE_KERNEL 1930 #endif 1931 1932 /** 1933 * vmalloc_exec - allocate virtually contiguous, executable memory 1934 * @size: allocation size 1935 * 1936 * Kernel-internal function to allocate enough pages to cover @size 1937 * the page level allocator and map them into contiguous and 1938 * executable kernel virtual space. 1939 * 1940 * For tight control over page level allocator and protection flags 1941 * use __vmalloc() instead. 1942 */ 1943 1944 void *vmalloc_exec(unsigned long size) 1945 { 1946 return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL_EXEC, 1947 NUMA_NO_NODE, __builtin_return_address(0)); 1948 } 1949 1950 #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32) 1951 #define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL 1952 #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA) 1953 #define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL 1954 #else 1955 #define GFP_VMALLOC32 GFP_KERNEL 1956 #endif 1957 1958 /** 1959 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) 1960 * @size: allocation size 1961 * 1962 * Allocate enough 32bit PA addressable pages to cover @size from the 1963 * page level allocator and map them into contiguous kernel virtual space. 1964 */ 1965 void *vmalloc_32(unsigned long size) 1966 { 1967 return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL, 1968 NUMA_NO_NODE, __builtin_return_address(0)); 1969 } 1970 EXPORT_SYMBOL(vmalloc_32); 1971 1972 /** 1973 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory 1974 * @size: allocation size 1975 * 1976 * The resulting memory area is 32bit addressable and zeroed so it can be 1977 * mapped to userspace without leaking data. 1978 */ 1979 void *vmalloc_32_user(unsigned long size) 1980 { 1981 struct vm_struct *area; 1982 void *ret; 1983 1984 ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL, 1985 NUMA_NO_NODE, __builtin_return_address(0)); 1986 if (ret) { 1987 area = find_vm_area(ret); 1988 area->flags |= VM_USERMAP; 1989 } 1990 return ret; 1991 } 1992 EXPORT_SYMBOL(vmalloc_32_user); 1993 1994 /* 1995 * small helper routine , copy contents to buf from addr. 1996 * If the page is not present, fill zero. 1997 */ 1998 1999 static int aligned_vread(char *buf, char *addr, unsigned long count) 2000 { 2001 struct page *p; 2002 int copied = 0; 2003 2004 while (count) { 2005 unsigned long offset, length; 2006 2007 offset = offset_in_page(addr); 2008 length = PAGE_SIZE - offset; 2009 if (length > count) 2010 length = count; 2011 p = vmalloc_to_page(addr); 2012 /* 2013 * To do safe access to this _mapped_ area, we need 2014 * lock. But adding lock here means that we need to add 2015 * overhead of vmalloc()/vfree() calles for this _debug_ 2016 * interface, rarely used. Instead of that, we'll use 2017 * kmap() and get small overhead in this access function. 2018 */ 2019 if (p) { 2020 /* 2021 * we can expect USER0 is not used (see vread/vwrite's 2022 * function description) 2023 */ 2024 void *map = kmap_atomic(p); 2025 memcpy(buf, map + offset, length); 2026 kunmap_atomic(map); 2027 } else 2028 memset(buf, 0, length); 2029 2030 addr += length; 2031 buf += length; 2032 copied += length; 2033 count -= length; 2034 } 2035 return copied; 2036 } 2037 2038 static int aligned_vwrite(char *buf, char *addr, unsigned long count) 2039 { 2040 struct page *p; 2041 int copied = 0; 2042 2043 while (count) { 2044 unsigned long offset, length; 2045 2046 offset = offset_in_page(addr); 2047 length = PAGE_SIZE - offset; 2048 if (length > count) 2049 length = count; 2050 p = vmalloc_to_page(addr); 2051 /* 2052 * To do safe access to this _mapped_ area, we need 2053 * lock. But adding lock here means that we need to add 2054 * overhead of vmalloc()/vfree() calles for this _debug_ 2055 * interface, rarely used. Instead of that, we'll use 2056 * kmap() and get small overhead in this access function. 2057 */ 2058 if (p) { 2059 /* 2060 * we can expect USER0 is not used (see vread/vwrite's 2061 * function description) 2062 */ 2063 void *map = kmap_atomic(p); 2064 memcpy(map + offset, buf, length); 2065 kunmap_atomic(map); 2066 } 2067 addr += length; 2068 buf += length; 2069 copied += length; 2070 count -= length; 2071 } 2072 return copied; 2073 } 2074 2075 /** 2076 * vread() - read vmalloc area in a safe way. 2077 * @buf: buffer for reading data 2078 * @addr: vm address. 2079 * @count: number of bytes to be read. 2080 * 2081 * Returns # of bytes which addr and buf should be increased. 2082 * (same number to @count). Returns 0 if [addr...addr+count) doesn't 2083 * includes any intersect with alive vmalloc area. 2084 * 2085 * This function checks that addr is a valid vmalloc'ed area, and 2086 * copy data from that area to a given buffer. If the given memory range 2087 * of [addr...addr+count) includes some valid address, data is copied to 2088 * proper area of @buf. If there are memory holes, they'll be zero-filled. 2089 * IOREMAP area is treated as memory hole and no copy is done. 2090 * 2091 * If [addr...addr+count) doesn't includes any intersects with alive 2092 * vm_struct area, returns 0. @buf should be kernel's buffer. 2093 * 2094 * Note: In usual ops, vread() is never necessary because the caller 2095 * should know vmalloc() area is valid and can use memcpy(). 2096 * This is for routines which have to access vmalloc area without 2097 * any informaion, as /dev/kmem. 2098 * 2099 */ 2100 2101 long vread(char *buf, char *addr, unsigned long count) 2102 { 2103 struct vmap_area *va; 2104 struct vm_struct *vm; 2105 char *vaddr, *buf_start = buf; 2106 unsigned long buflen = count; 2107 unsigned long n; 2108 2109 /* Don't allow overflow */ 2110 if ((unsigned long) addr + count < count) 2111 count = -(unsigned long) addr; 2112 2113 spin_lock(&vmap_area_lock); 2114 list_for_each_entry(va, &vmap_area_list, list) { 2115 if (!count) 2116 break; 2117 2118 if (!(va->flags & VM_VM_AREA)) 2119 continue; 2120 2121 vm = va->vm; 2122 vaddr = (char *) vm->addr; 2123 if (addr >= vaddr + get_vm_area_size(vm)) 2124 continue; 2125 while (addr < vaddr) { 2126 if (count == 0) 2127 goto finished; 2128 *buf = '\0'; 2129 buf++; 2130 addr++; 2131 count--; 2132 } 2133 n = vaddr + get_vm_area_size(vm) - addr; 2134 if (n > count) 2135 n = count; 2136 if (!(vm->flags & VM_IOREMAP)) 2137 aligned_vread(buf, addr, n); 2138 else /* IOREMAP area is treated as memory hole */ 2139 memset(buf, 0, n); 2140 buf += n; 2141 addr += n; 2142 count -= n; 2143 } 2144 finished: 2145 spin_unlock(&vmap_area_lock); 2146 2147 if (buf == buf_start) 2148 return 0; 2149 /* zero-fill memory holes */ 2150 if (buf != buf_start + buflen) 2151 memset(buf, 0, buflen - (buf - buf_start)); 2152 2153 return buflen; 2154 } 2155 2156 /** 2157 * vwrite() - write vmalloc area in a safe way. 2158 * @buf: buffer for source data 2159 * @addr: vm address. 2160 * @count: number of bytes to be read. 2161 * 2162 * Returns # of bytes which addr and buf should be incresed. 2163 * (same number to @count). 2164 * If [addr...addr+count) doesn't includes any intersect with valid 2165 * vmalloc area, returns 0. 2166 * 2167 * This function checks that addr is a valid vmalloc'ed area, and 2168 * copy data from a buffer to the given addr. If specified range of 2169 * [addr...addr+count) includes some valid address, data is copied from 2170 * proper area of @buf. If there are memory holes, no copy to hole. 2171 * IOREMAP area is treated as memory hole and no copy is done. 2172 * 2173 * If [addr...addr+count) doesn't includes any intersects with alive 2174 * vm_struct area, returns 0. @buf should be kernel's buffer. 2175 * 2176 * Note: In usual ops, vwrite() is never necessary because the caller 2177 * should know vmalloc() area is valid and can use memcpy(). 2178 * This is for routines which have to access vmalloc area without 2179 * any informaion, as /dev/kmem. 2180 */ 2181 2182 long vwrite(char *buf, char *addr, unsigned long count) 2183 { 2184 struct vmap_area *va; 2185 struct vm_struct *vm; 2186 char *vaddr; 2187 unsigned long n, buflen; 2188 int copied = 0; 2189 2190 /* Don't allow overflow */ 2191 if ((unsigned long) addr + count < count) 2192 count = -(unsigned long) addr; 2193 buflen = count; 2194 2195 spin_lock(&vmap_area_lock); 2196 list_for_each_entry(va, &vmap_area_list, list) { 2197 if (!count) 2198 break; 2199 2200 if (!(va->flags & VM_VM_AREA)) 2201 continue; 2202 2203 vm = va->vm; 2204 vaddr = (char *) vm->addr; 2205 if (addr >= vaddr + get_vm_area_size(vm)) 2206 continue; 2207 while (addr < vaddr) { 2208 if (count == 0) 2209 goto finished; 2210 buf++; 2211 addr++; 2212 count--; 2213 } 2214 n = vaddr + get_vm_area_size(vm) - addr; 2215 if (n > count) 2216 n = count; 2217 if (!(vm->flags & VM_IOREMAP)) { 2218 aligned_vwrite(buf, addr, n); 2219 copied++; 2220 } 2221 buf += n; 2222 addr += n; 2223 count -= n; 2224 } 2225 finished: 2226 spin_unlock(&vmap_area_lock); 2227 if (!copied) 2228 return 0; 2229 return buflen; 2230 } 2231 2232 /** 2233 * remap_vmalloc_range_partial - map vmalloc pages to userspace 2234 * @vma: vma to cover 2235 * @uaddr: target user address to start at 2236 * @kaddr: virtual address of vmalloc kernel memory 2237 * @size: size of map area 2238 * 2239 * Returns: 0 for success, -Exxx on failure 2240 * 2241 * This function checks that @kaddr is a valid vmalloc'ed area, 2242 * and that it is big enough to cover the range starting at 2243 * @uaddr in @vma. Will return failure if that criteria isn't 2244 * met. 2245 * 2246 * Similar to remap_pfn_range() (see mm/memory.c) 2247 */ 2248 int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr, 2249 void *kaddr, unsigned long size) 2250 { 2251 struct vm_struct *area; 2252 2253 size = PAGE_ALIGN(size); 2254 2255 if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr)) 2256 return -EINVAL; 2257 2258 area = find_vm_area(kaddr); 2259 if (!area) 2260 return -EINVAL; 2261 2262 if (!(area->flags & VM_USERMAP)) 2263 return -EINVAL; 2264 2265 if (kaddr + size > area->addr + area->size) 2266 return -EINVAL; 2267 2268 do { 2269 struct page *page = vmalloc_to_page(kaddr); 2270 int ret; 2271 2272 ret = vm_insert_page(vma, uaddr, page); 2273 if (ret) 2274 return ret; 2275 2276 uaddr += PAGE_SIZE; 2277 kaddr += PAGE_SIZE; 2278 size -= PAGE_SIZE; 2279 } while (size > 0); 2280 2281 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 2282 2283 return 0; 2284 } 2285 EXPORT_SYMBOL(remap_vmalloc_range_partial); 2286 2287 /** 2288 * remap_vmalloc_range - map vmalloc pages to userspace 2289 * @vma: vma to cover (map full range of vma) 2290 * @addr: vmalloc memory 2291 * @pgoff: number of pages into addr before first page to map 2292 * 2293 * Returns: 0 for success, -Exxx on failure 2294 * 2295 * This function checks that addr is a valid vmalloc'ed area, and 2296 * that it is big enough to cover the vma. Will return failure if 2297 * that criteria isn't met. 2298 * 2299 * Similar to remap_pfn_range() (see mm/memory.c) 2300 */ 2301 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, 2302 unsigned long pgoff) 2303 { 2304 return remap_vmalloc_range_partial(vma, vma->vm_start, 2305 addr + (pgoff << PAGE_SHIFT), 2306 vma->vm_end - vma->vm_start); 2307 } 2308 EXPORT_SYMBOL(remap_vmalloc_range); 2309 2310 /* 2311 * Implement a stub for vmalloc_sync_all() if the architecture chose not to 2312 * have one. 2313 */ 2314 void __weak vmalloc_sync_all(void) 2315 { 2316 } 2317 2318 2319 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data) 2320 { 2321 pte_t ***p = data; 2322 2323 if (p) { 2324 *(*p) = pte; 2325 (*p)++; 2326 } 2327 return 0; 2328 } 2329 2330 /** 2331 * alloc_vm_area - allocate a range of kernel address space 2332 * @size: size of the area 2333 * @ptes: returns the PTEs for the address space 2334 * 2335 * Returns: NULL on failure, vm_struct on success 2336 * 2337 * This function reserves a range of kernel address space, and 2338 * allocates pagetables to map that range. No actual mappings 2339 * are created. 2340 * 2341 * If @ptes is non-NULL, pointers to the PTEs (in init_mm) 2342 * allocated for the VM area are returned. 2343 */ 2344 struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes) 2345 { 2346 struct vm_struct *area; 2347 2348 area = get_vm_area_caller(size, VM_IOREMAP, 2349 __builtin_return_address(0)); 2350 if (area == NULL) 2351 return NULL; 2352 2353 /* 2354 * This ensures that page tables are constructed for this region 2355 * of kernel virtual address space and mapped into init_mm. 2356 */ 2357 if (apply_to_page_range(&init_mm, (unsigned long)area->addr, 2358 size, f, ptes ? &ptes : NULL)) { 2359 free_vm_area(area); 2360 return NULL; 2361 } 2362 2363 return area; 2364 } 2365 EXPORT_SYMBOL_GPL(alloc_vm_area); 2366 2367 void free_vm_area(struct vm_struct *area) 2368 { 2369 struct vm_struct *ret; 2370 ret = remove_vm_area(area->addr); 2371 BUG_ON(ret != area); 2372 kfree(area); 2373 } 2374 EXPORT_SYMBOL_GPL(free_vm_area); 2375 2376 #ifdef CONFIG_SMP 2377 static struct vmap_area *node_to_va(struct rb_node *n) 2378 { 2379 return rb_entry_safe(n, struct vmap_area, rb_node); 2380 } 2381 2382 /** 2383 * pvm_find_next_prev - find the next and prev vmap_area surrounding @end 2384 * @end: target address 2385 * @pnext: out arg for the next vmap_area 2386 * @pprev: out arg for the previous vmap_area 2387 * 2388 * Returns: %true if either or both of next and prev are found, 2389 * %false if no vmap_area exists 2390 * 2391 * Find vmap_areas end addresses of which enclose @end. ie. if not 2392 * NULL, *pnext->va_end > @end and *pprev->va_end <= @end. 2393 */ 2394 static bool pvm_find_next_prev(unsigned long end, 2395 struct vmap_area **pnext, 2396 struct vmap_area **pprev) 2397 { 2398 struct rb_node *n = vmap_area_root.rb_node; 2399 struct vmap_area *va = NULL; 2400 2401 while (n) { 2402 va = rb_entry(n, struct vmap_area, rb_node); 2403 if (end < va->va_end) 2404 n = n->rb_left; 2405 else if (end > va->va_end) 2406 n = n->rb_right; 2407 else 2408 break; 2409 } 2410 2411 if (!va) 2412 return false; 2413 2414 if (va->va_end > end) { 2415 *pnext = va; 2416 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node)); 2417 } else { 2418 *pprev = va; 2419 *pnext = node_to_va(rb_next(&(*pprev)->rb_node)); 2420 } 2421 return true; 2422 } 2423 2424 /** 2425 * pvm_determine_end - find the highest aligned address between two vmap_areas 2426 * @pnext: in/out arg for the next vmap_area 2427 * @pprev: in/out arg for the previous vmap_area 2428 * @align: alignment 2429 * 2430 * Returns: determined end address 2431 * 2432 * Find the highest aligned address between *@pnext and *@pprev below 2433 * VMALLOC_END. *@pnext and *@pprev are adjusted so that the aligned 2434 * down address is between the end addresses of the two vmap_areas. 2435 * 2436 * Please note that the address returned by this function may fall 2437 * inside *@pnext vmap_area. The caller is responsible for checking 2438 * that. 2439 */ 2440 static unsigned long pvm_determine_end(struct vmap_area **pnext, 2441 struct vmap_area **pprev, 2442 unsigned long align) 2443 { 2444 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1); 2445 unsigned long addr; 2446 2447 if (*pnext) 2448 addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end); 2449 else 2450 addr = vmalloc_end; 2451 2452 while (*pprev && (*pprev)->va_end > addr) { 2453 *pnext = *pprev; 2454 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node)); 2455 } 2456 2457 return addr; 2458 } 2459 2460 /** 2461 * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator 2462 * @offsets: array containing offset of each area 2463 * @sizes: array containing size of each area 2464 * @nr_vms: the number of areas to allocate 2465 * @align: alignment, all entries in @offsets and @sizes must be aligned to this 2466 * 2467 * Returns: kmalloc'd vm_struct pointer array pointing to allocated 2468 * vm_structs on success, %NULL on failure 2469 * 2470 * Percpu allocator wants to use congruent vm areas so that it can 2471 * maintain the offsets among percpu areas. This function allocates 2472 * congruent vmalloc areas for it with GFP_KERNEL. These areas tend to 2473 * be scattered pretty far, distance between two areas easily going up 2474 * to gigabytes. To avoid interacting with regular vmallocs, these 2475 * areas are allocated from top. 2476 * 2477 * Despite its complicated look, this allocator is rather simple. It 2478 * does everything top-down and scans areas from the end looking for 2479 * matching slot. While scanning, if any of the areas overlaps with 2480 * existing vmap_area, the base address is pulled down to fit the 2481 * area. Scanning is repeated till all the areas fit and then all 2482 * necessary data structres are inserted and the result is returned. 2483 */ 2484 struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, 2485 const size_t *sizes, int nr_vms, 2486 size_t align) 2487 { 2488 const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align); 2489 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1); 2490 struct vmap_area **vas, *prev, *next; 2491 struct vm_struct **vms; 2492 int area, area2, last_area, term_area; 2493 unsigned long base, start, end, last_end; 2494 bool purged = false; 2495 2496 /* verify parameters and allocate data structures */ 2497 BUG_ON(offset_in_page(align) || !is_power_of_2(align)); 2498 for (last_area = 0, area = 0; area < nr_vms; area++) { 2499 start = offsets[area]; 2500 end = start + sizes[area]; 2501 2502 /* is everything aligned properly? */ 2503 BUG_ON(!IS_ALIGNED(offsets[area], align)); 2504 BUG_ON(!IS_ALIGNED(sizes[area], align)); 2505 2506 /* detect the area with the highest address */ 2507 if (start > offsets[last_area]) 2508 last_area = area; 2509 2510 for (area2 = 0; area2 < nr_vms; area2++) { 2511 unsigned long start2 = offsets[area2]; 2512 unsigned long end2 = start2 + sizes[area2]; 2513 2514 if (area2 == area) 2515 continue; 2516 2517 BUG_ON(start2 >= start && start2 < end); 2518 BUG_ON(end2 <= end && end2 > start); 2519 } 2520 } 2521 last_end = offsets[last_area] + sizes[last_area]; 2522 2523 if (vmalloc_end - vmalloc_start < last_end) { 2524 WARN_ON(true); 2525 return NULL; 2526 } 2527 2528 vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL); 2529 vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL); 2530 if (!vas || !vms) 2531 goto err_free2; 2532 2533 for (area = 0; area < nr_vms; area++) { 2534 vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL); 2535 vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL); 2536 if (!vas[area] || !vms[area]) 2537 goto err_free; 2538 } 2539 retry: 2540 spin_lock(&vmap_area_lock); 2541 2542 /* start scanning - we scan from the top, begin with the last area */ 2543 area = term_area = last_area; 2544 start = offsets[area]; 2545 end = start + sizes[area]; 2546 2547 if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) { 2548 base = vmalloc_end - last_end; 2549 goto found; 2550 } 2551 base = pvm_determine_end(&next, &prev, align) - end; 2552 2553 while (true) { 2554 BUG_ON(next && next->va_end <= base + end); 2555 BUG_ON(prev && prev->va_end > base + end); 2556 2557 /* 2558 * base might have underflowed, add last_end before 2559 * comparing. 2560 */ 2561 if (base + last_end < vmalloc_start + last_end) { 2562 spin_unlock(&vmap_area_lock); 2563 if (!purged) { 2564 purge_vmap_area_lazy(); 2565 purged = true; 2566 goto retry; 2567 } 2568 goto err_free; 2569 } 2570 2571 /* 2572 * If next overlaps, move base downwards so that it's 2573 * right below next and then recheck. 2574 */ 2575 if (next && next->va_start < base + end) { 2576 base = pvm_determine_end(&next, &prev, align) - end; 2577 term_area = area; 2578 continue; 2579 } 2580 2581 /* 2582 * If prev overlaps, shift down next and prev and move 2583 * base so that it's right below new next and then 2584 * recheck. 2585 */ 2586 if (prev && prev->va_end > base + start) { 2587 next = prev; 2588 prev = node_to_va(rb_prev(&next->rb_node)); 2589 base = pvm_determine_end(&next, &prev, align) - end; 2590 term_area = area; 2591 continue; 2592 } 2593 2594 /* 2595 * This area fits, move on to the previous one. If 2596 * the previous one is the terminal one, we're done. 2597 */ 2598 area = (area + nr_vms - 1) % nr_vms; 2599 if (area == term_area) 2600 break; 2601 start = offsets[area]; 2602 end = start + sizes[area]; 2603 pvm_find_next_prev(base + end, &next, &prev); 2604 } 2605 found: 2606 /* we've found a fitting base, insert all va's */ 2607 for (area = 0; area < nr_vms; area++) { 2608 struct vmap_area *va = vas[area]; 2609 2610 va->va_start = base + offsets[area]; 2611 va->va_end = va->va_start + sizes[area]; 2612 __insert_vmap_area(va); 2613 } 2614 2615 vmap_area_pcpu_hole = base + offsets[last_area]; 2616 2617 spin_unlock(&vmap_area_lock); 2618 2619 /* insert all vm's */ 2620 for (area = 0; area < nr_vms; area++) 2621 setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC, 2622 pcpu_get_vm_areas); 2623 2624 kfree(vas); 2625 return vms; 2626 2627 err_free: 2628 for (area = 0; area < nr_vms; area++) { 2629 kfree(vas[area]); 2630 kfree(vms[area]); 2631 } 2632 err_free2: 2633 kfree(vas); 2634 kfree(vms); 2635 return NULL; 2636 } 2637 2638 /** 2639 * pcpu_free_vm_areas - free vmalloc areas for percpu allocator 2640 * @vms: vm_struct pointer array returned by pcpu_get_vm_areas() 2641 * @nr_vms: the number of allocated areas 2642 * 2643 * Free vm_structs and the array allocated by pcpu_get_vm_areas(). 2644 */ 2645 void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) 2646 { 2647 int i; 2648 2649 for (i = 0; i < nr_vms; i++) 2650 free_vm_area(vms[i]); 2651 kfree(vms); 2652 } 2653 #endif /* CONFIG_SMP */ 2654 2655 #ifdef CONFIG_PROC_FS 2656 static void *s_start(struct seq_file *m, loff_t *pos) 2657 __acquires(&vmap_area_lock) 2658 { 2659 spin_lock(&vmap_area_lock); 2660 return seq_list_start(&vmap_area_list, *pos); 2661 } 2662 2663 static void *s_next(struct seq_file *m, void *p, loff_t *pos) 2664 { 2665 return seq_list_next(p, &vmap_area_list, pos); 2666 } 2667 2668 static void s_stop(struct seq_file *m, void *p) 2669 __releases(&vmap_area_lock) 2670 { 2671 spin_unlock(&vmap_area_lock); 2672 } 2673 2674 static void show_numa_info(struct seq_file *m, struct vm_struct *v) 2675 { 2676 if (IS_ENABLED(CONFIG_NUMA)) { 2677 unsigned int nr, *counters = m->private; 2678 2679 if (!counters) 2680 return; 2681 2682 if (v->flags & VM_UNINITIALIZED) 2683 return; 2684 /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ 2685 smp_rmb(); 2686 2687 memset(counters, 0, nr_node_ids * sizeof(unsigned int)); 2688 2689 for (nr = 0; nr < v->nr_pages; nr++) 2690 counters[page_to_nid(v->pages[nr])]++; 2691 2692 for_each_node_state(nr, N_HIGH_MEMORY) 2693 if (counters[nr]) 2694 seq_printf(m, " N%u=%u", nr, counters[nr]); 2695 } 2696 } 2697 2698 static int s_show(struct seq_file *m, void *p) 2699 { 2700 struct vmap_area *va; 2701 struct vm_struct *v; 2702 2703 va = list_entry(p, struct vmap_area, list); 2704 2705 /* 2706 * s_show can encounter race with remove_vm_area, !VM_VM_AREA on 2707 * behalf of vmap area is being tear down or vm_map_ram allocation. 2708 */ 2709 if (!(va->flags & VM_VM_AREA)) { 2710 seq_printf(m, "0x%pK-0x%pK %7ld %s\n", 2711 (void *)va->va_start, (void *)va->va_end, 2712 va->va_end - va->va_start, 2713 va->flags & VM_LAZY_FREE ? "unpurged vm_area" : "vm_map_ram"); 2714 2715 return 0; 2716 } 2717 2718 v = va->vm; 2719 2720 seq_printf(m, "0x%pK-0x%pK %7ld", 2721 v->addr, v->addr + v->size, v->size); 2722 2723 if (v->caller) 2724 seq_printf(m, " %pS", v->caller); 2725 2726 if (v->nr_pages) 2727 seq_printf(m, " pages=%d", v->nr_pages); 2728 2729 if (v->phys_addr) 2730 seq_printf(m, " phys=%pa", &v->phys_addr); 2731 2732 if (v->flags & VM_IOREMAP) 2733 seq_puts(m, " ioremap"); 2734 2735 if (v->flags & VM_ALLOC) 2736 seq_puts(m, " vmalloc"); 2737 2738 if (v->flags & VM_MAP) 2739 seq_puts(m, " vmap"); 2740 2741 if (v->flags & VM_USERMAP) 2742 seq_puts(m, " user"); 2743 2744 if (is_vmalloc_addr(v->pages)) 2745 seq_puts(m, " vpages"); 2746 2747 show_numa_info(m, v); 2748 seq_putc(m, '\n'); 2749 return 0; 2750 } 2751 2752 static const struct seq_operations vmalloc_op = { 2753 .start = s_start, 2754 .next = s_next, 2755 .stop = s_stop, 2756 .show = s_show, 2757 }; 2758 2759 static int vmalloc_open(struct inode *inode, struct file *file) 2760 { 2761 if (IS_ENABLED(CONFIG_NUMA)) 2762 return seq_open_private(file, &vmalloc_op, 2763 nr_node_ids * sizeof(unsigned int)); 2764 else 2765 return seq_open(file, &vmalloc_op); 2766 } 2767 2768 static const struct file_operations proc_vmalloc_operations = { 2769 .open = vmalloc_open, 2770 .read = seq_read, 2771 .llseek = seq_lseek, 2772 .release = seq_release_private, 2773 }; 2774 2775 static int __init proc_vmalloc_init(void) 2776 { 2777 proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations); 2778 return 0; 2779 } 2780 module_init(proc_vmalloc_init); 2781 2782 #endif 2783 2784