1 /* 2 * linux/mm/vmalloc.c 3 * 4 * Copyright (C) 1993 Linus Torvalds 5 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 6 * SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000 7 * Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002 8 * Numa awareness, Christoph Lameter, SGI, June 2005 9 */ 10 11 #include <linux/vmalloc.h> 12 #include <linux/mm.h> 13 #include <linux/module.h> 14 #include <linux/highmem.h> 15 #include <linux/sched.h> 16 #include <linux/slab.h> 17 #include <linux/spinlock.h> 18 #include <linux/interrupt.h> 19 #include <linux/proc_fs.h> 20 #include <linux/seq_file.h> 21 #include <linux/debugobjects.h> 22 #include <linux/kallsyms.h> 23 #include <linux/list.h> 24 #include <linux/rbtree.h> 25 #include <linux/radix-tree.h> 26 #include <linux/rcupdate.h> 27 #include <linux/pfn.h> 28 #include <linux/kmemleak.h> 29 #include <linux/atomic.h> 30 #include <linux/compiler.h> 31 #include <linux/llist.h> 32 33 #include <asm/uaccess.h> 34 #include <asm/tlbflush.h> 35 #include <asm/shmparam.h> 36 37 struct vfree_deferred { 38 struct llist_head list; 39 struct work_struct wq; 40 }; 41 static DEFINE_PER_CPU(struct vfree_deferred, vfree_deferred); 42 43 static void __vunmap(const void *, int); 44 45 static void free_work(struct work_struct *w) 46 { 47 struct vfree_deferred *p = container_of(w, struct vfree_deferred, wq); 48 struct llist_node *llnode = llist_del_all(&p->list); 49 while (llnode) { 50 void *p = llnode; 51 llnode = llist_next(llnode); 52 __vunmap(p, 1); 53 } 54 } 55 56 /*** Page table manipulation functions ***/ 57 58 static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end) 59 { 60 pte_t *pte; 61 62 pte = pte_offset_kernel(pmd, addr); 63 do { 64 pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte); 65 WARN_ON(!pte_none(ptent) && !pte_present(ptent)); 66 } while (pte++, addr += PAGE_SIZE, addr != end); 67 } 68 69 static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end) 70 { 71 pmd_t *pmd; 72 unsigned long next; 73 74 pmd = pmd_offset(pud, addr); 75 do { 76 next = pmd_addr_end(addr, end); 77 if (pmd_none_or_clear_bad(pmd)) 78 continue; 79 vunmap_pte_range(pmd, addr, next); 80 } while (pmd++, addr = next, addr != end); 81 } 82 83 static void vunmap_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end) 84 { 85 pud_t *pud; 86 unsigned long next; 87 88 pud = pud_offset(pgd, addr); 89 do { 90 next = pud_addr_end(addr, end); 91 if (pud_none_or_clear_bad(pud)) 92 continue; 93 vunmap_pmd_range(pud, addr, next); 94 } while (pud++, addr = next, addr != end); 95 } 96 97 static void vunmap_page_range(unsigned long addr, unsigned long end) 98 { 99 pgd_t *pgd; 100 unsigned long next; 101 102 BUG_ON(addr >= end); 103 pgd = pgd_offset_k(addr); 104 do { 105 next = pgd_addr_end(addr, end); 106 if (pgd_none_or_clear_bad(pgd)) 107 continue; 108 vunmap_pud_range(pgd, addr, next); 109 } while (pgd++, addr = next, addr != end); 110 } 111 112 static int vmap_pte_range(pmd_t *pmd, unsigned long addr, 113 unsigned long end, pgprot_t prot, struct page **pages, int *nr) 114 { 115 pte_t *pte; 116 117 /* 118 * nr is a running index into the array which helps higher level 119 * callers keep track of where we're up to. 120 */ 121 122 pte = pte_alloc_kernel(pmd, addr); 123 if (!pte) 124 return -ENOMEM; 125 do { 126 struct page *page = pages[*nr]; 127 128 if (WARN_ON(!pte_none(*pte))) 129 return -EBUSY; 130 if (WARN_ON(!page)) 131 return -ENOMEM; 132 set_pte_at(&init_mm, addr, pte, mk_pte(page, prot)); 133 (*nr)++; 134 } while (pte++, addr += PAGE_SIZE, addr != end); 135 return 0; 136 } 137 138 static int vmap_pmd_range(pud_t *pud, unsigned long addr, 139 unsigned long end, pgprot_t prot, struct page **pages, int *nr) 140 { 141 pmd_t *pmd; 142 unsigned long next; 143 144 pmd = pmd_alloc(&init_mm, pud, addr); 145 if (!pmd) 146 return -ENOMEM; 147 do { 148 next = pmd_addr_end(addr, end); 149 if (vmap_pte_range(pmd, addr, next, prot, pages, nr)) 150 return -ENOMEM; 151 } while (pmd++, addr = next, addr != end); 152 return 0; 153 } 154 155 static int vmap_pud_range(pgd_t *pgd, unsigned long addr, 156 unsigned long end, pgprot_t prot, struct page **pages, int *nr) 157 { 158 pud_t *pud; 159 unsigned long next; 160 161 pud = pud_alloc(&init_mm, pgd, addr); 162 if (!pud) 163 return -ENOMEM; 164 do { 165 next = pud_addr_end(addr, end); 166 if (vmap_pmd_range(pud, addr, next, prot, pages, nr)) 167 return -ENOMEM; 168 } while (pud++, addr = next, addr != end); 169 return 0; 170 } 171 172 /* 173 * Set up page tables in kva (addr, end). The ptes shall have prot "prot", and 174 * will have pfns corresponding to the "pages" array. 175 * 176 * Ie. pte at addr+N*PAGE_SIZE shall point to pfn corresponding to pages[N] 177 */ 178 static int vmap_page_range_noflush(unsigned long start, unsigned long end, 179 pgprot_t prot, struct page **pages) 180 { 181 pgd_t *pgd; 182 unsigned long next; 183 unsigned long addr = start; 184 int err = 0; 185 int nr = 0; 186 187 BUG_ON(addr >= end); 188 pgd = pgd_offset_k(addr); 189 do { 190 next = pgd_addr_end(addr, end); 191 err = vmap_pud_range(pgd, addr, next, prot, pages, &nr); 192 if (err) 193 return err; 194 } while (pgd++, addr = next, addr != end); 195 196 return nr; 197 } 198 199 static int vmap_page_range(unsigned long start, unsigned long end, 200 pgprot_t prot, struct page **pages) 201 { 202 int ret; 203 204 ret = vmap_page_range_noflush(start, end, prot, pages); 205 flush_cache_vmap(start, end); 206 return ret; 207 } 208 209 int is_vmalloc_or_module_addr(const void *x) 210 { 211 /* 212 * ARM, x86-64 and sparc64 put modules in a special place, 213 * and fall back on vmalloc() if that fails. Others 214 * just put it in the vmalloc space. 215 */ 216 #if defined(CONFIG_MODULES) && defined(MODULES_VADDR) 217 unsigned long addr = (unsigned long)x; 218 if (addr >= MODULES_VADDR && addr < MODULES_END) 219 return 1; 220 #endif 221 return is_vmalloc_addr(x); 222 } 223 224 /* 225 * Walk a vmap address to the struct page it maps. 226 */ 227 struct page *vmalloc_to_page(const void *vmalloc_addr) 228 { 229 unsigned long addr = (unsigned long) vmalloc_addr; 230 struct page *page = NULL; 231 pgd_t *pgd = pgd_offset_k(addr); 232 233 /* 234 * XXX we might need to change this if we add VIRTUAL_BUG_ON for 235 * architectures that do not vmalloc module space 236 */ 237 VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr)); 238 239 if (!pgd_none(*pgd)) { 240 pud_t *pud = pud_offset(pgd, addr); 241 if (!pud_none(*pud)) { 242 pmd_t *pmd = pmd_offset(pud, addr); 243 if (!pmd_none(*pmd)) { 244 pte_t *ptep, pte; 245 246 ptep = pte_offset_map(pmd, addr); 247 pte = *ptep; 248 if (pte_present(pte)) 249 page = pte_page(pte); 250 pte_unmap(ptep); 251 } 252 } 253 } 254 return page; 255 } 256 EXPORT_SYMBOL(vmalloc_to_page); 257 258 /* 259 * Map a vmalloc()-space virtual address to the physical page frame number. 260 */ 261 unsigned long vmalloc_to_pfn(const void *vmalloc_addr) 262 { 263 return page_to_pfn(vmalloc_to_page(vmalloc_addr)); 264 } 265 EXPORT_SYMBOL(vmalloc_to_pfn); 266 267 268 /*** Global kva allocator ***/ 269 270 #define VM_LAZY_FREE 0x01 271 #define VM_LAZY_FREEING 0x02 272 #define VM_VM_AREA 0x04 273 274 static DEFINE_SPINLOCK(vmap_area_lock); 275 /* Export for kexec only */ 276 LIST_HEAD(vmap_area_list); 277 static struct rb_root vmap_area_root = RB_ROOT; 278 279 /* The vmap cache globals are protected by vmap_area_lock */ 280 static struct rb_node *free_vmap_cache; 281 static unsigned long cached_hole_size; 282 static unsigned long cached_vstart; 283 static unsigned long cached_align; 284 285 static unsigned long vmap_area_pcpu_hole; 286 287 static struct vmap_area *__find_vmap_area(unsigned long addr) 288 { 289 struct rb_node *n = vmap_area_root.rb_node; 290 291 while (n) { 292 struct vmap_area *va; 293 294 va = rb_entry(n, struct vmap_area, rb_node); 295 if (addr < va->va_start) 296 n = n->rb_left; 297 else if (addr >= va->va_end) 298 n = n->rb_right; 299 else 300 return va; 301 } 302 303 return NULL; 304 } 305 306 static void __insert_vmap_area(struct vmap_area *va) 307 { 308 struct rb_node **p = &vmap_area_root.rb_node; 309 struct rb_node *parent = NULL; 310 struct rb_node *tmp; 311 312 while (*p) { 313 struct vmap_area *tmp_va; 314 315 parent = *p; 316 tmp_va = rb_entry(parent, struct vmap_area, rb_node); 317 if (va->va_start < tmp_va->va_end) 318 p = &(*p)->rb_left; 319 else if (va->va_end > tmp_va->va_start) 320 p = &(*p)->rb_right; 321 else 322 BUG(); 323 } 324 325 rb_link_node(&va->rb_node, parent, p); 326 rb_insert_color(&va->rb_node, &vmap_area_root); 327 328 /* address-sort this list */ 329 tmp = rb_prev(&va->rb_node); 330 if (tmp) { 331 struct vmap_area *prev; 332 prev = rb_entry(tmp, struct vmap_area, rb_node); 333 list_add_rcu(&va->list, &prev->list); 334 } else 335 list_add_rcu(&va->list, &vmap_area_list); 336 } 337 338 static void purge_vmap_area_lazy(void); 339 340 /* 341 * Allocate a region of KVA of the specified size and alignment, within the 342 * vstart and vend. 343 */ 344 static struct vmap_area *alloc_vmap_area(unsigned long size, 345 unsigned long align, 346 unsigned long vstart, unsigned long vend, 347 int node, gfp_t gfp_mask) 348 { 349 struct vmap_area *va; 350 struct rb_node *n; 351 unsigned long addr; 352 int purged = 0; 353 struct vmap_area *first; 354 355 BUG_ON(!size); 356 BUG_ON(size & ~PAGE_MASK); 357 BUG_ON(!is_power_of_2(align)); 358 359 va = kmalloc_node(sizeof(struct vmap_area), 360 gfp_mask & GFP_RECLAIM_MASK, node); 361 if (unlikely(!va)) 362 return ERR_PTR(-ENOMEM); 363 364 /* 365 * Only scan the relevant parts containing pointers to other objects 366 * to avoid false negatives. 367 */ 368 kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK); 369 370 retry: 371 spin_lock(&vmap_area_lock); 372 /* 373 * Invalidate cache if we have more permissive parameters. 374 * cached_hole_size notes the largest hole noticed _below_ 375 * the vmap_area cached in free_vmap_cache: if size fits 376 * into that hole, we want to scan from vstart to reuse 377 * the hole instead of allocating above free_vmap_cache. 378 * Note that __free_vmap_area may update free_vmap_cache 379 * without updating cached_hole_size or cached_align. 380 */ 381 if (!free_vmap_cache || 382 size < cached_hole_size || 383 vstart < cached_vstart || 384 align < cached_align) { 385 nocache: 386 cached_hole_size = 0; 387 free_vmap_cache = NULL; 388 } 389 /* record if we encounter less permissive parameters */ 390 cached_vstart = vstart; 391 cached_align = align; 392 393 /* find starting point for our search */ 394 if (free_vmap_cache) { 395 first = rb_entry(free_vmap_cache, struct vmap_area, rb_node); 396 addr = ALIGN(first->va_end, align); 397 if (addr < vstart) 398 goto nocache; 399 if (addr + size < addr) 400 goto overflow; 401 402 } else { 403 addr = ALIGN(vstart, align); 404 if (addr + size < addr) 405 goto overflow; 406 407 n = vmap_area_root.rb_node; 408 first = NULL; 409 410 while (n) { 411 struct vmap_area *tmp; 412 tmp = rb_entry(n, struct vmap_area, rb_node); 413 if (tmp->va_end >= addr) { 414 first = tmp; 415 if (tmp->va_start <= addr) 416 break; 417 n = n->rb_left; 418 } else 419 n = n->rb_right; 420 } 421 422 if (!first) 423 goto found; 424 } 425 426 /* from the starting point, walk areas until a suitable hole is found */ 427 while (addr + size > first->va_start && addr + size <= vend) { 428 if (addr + cached_hole_size < first->va_start) 429 cached_hole_size = first->va_start - addr; 430 addr = ALIGN(first->va_end, align); 431 if (addr + size < addr) 432 goto overflow; 433 434 if (list_is_last(&first->list, &vmap_area_list)) 435 goto found; 436 437 first = list_entry(first->list.next, 438 struct vmap_area, list); 439 } 440 441 found: 442 if (addr + size > vend) 443 goto overflow; 444 445 va->va_start = addr; 446 va->va_end = addr + size; 447 va->flags = 0; 448 __insert_vmap_area(va); 449 free_vmap_cache = &va->rb_node; 450 spin_unlock(&vmap_area_lock); 451 452 BUG_ON(va->va_start & (align-1)); 453 BUG_ON(va->va_start < vstart); 454 BUG_ON(va->va_end > vend); 455 456 return va; 457 458 overflow: 459 spin_unlock(&vmap_area_lock); 460 if (!purged) { 461 purge_vmap_area_lazy(); 462 purged = 1; 463 goto retry; 464 } 465 if (printk_ratelimit()) 466 printk(KERN_WARNING 467 "vmap allocation for size %lu failed: " 468 "use vmalloc=<size> to increase size.\n", size); 469 kfree(va); 470 return ERR_PTR(-EBUSY); 471 } 472 473 static void __free_vmap_area(struct vmap_area *va) 474 { 475 BUG_ON(RB_EMPTY_NODE(&va->rb_node)); 476 477 if (free_vmap_cache) { 478 if (va->va_end < cached_vstart) { 479 free_vmap_cache = NULL; 480 } else { 481 struct vmap_area *cache; 482 cache = rb_entry(free_vmap_cache, struct vmap_area, rb_node); 483 if (va->va_start <= cache->va_start) { 484 free_vmap_cache = rb_prev(&va->rb_node); 485 /* 486 * We don't try to update cached_hole_size or 487 * cached_align, but it won't go very wrong. 488 */ 489 } 490 } 491 } 492 rb_erase(&va->rb_node, &vmap_area_root); 493 RB_CLEAR_NODE(&va->rb_node); 494 list_del_rcu(&va->list); 495 496 /* 497 * Track the highest possible candidate for pcpu area 498 * allocation. Areas outside of vmalloc area can be returned 499 * here too, consider only end addresses which fall inside 500 * vmalloc area proper. 501 */ 502 if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END) 503 vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end); 504 505 kfree_rcu(va, rcu_head); 506 } 507 508 /* 509 * Free a region of KVA allocated by alloc_vmap_area 510 */ 511 static void free_vmap_area(struct vmap_area *va) 512 { 513 spin_lock(&vmap_area_lock); 514 __free_vmap_area(va); 515 spin_unlock(&vmap_area_lock); 516 } 517 518 /* 519 * Clear the pagetable entries of a given vmap_area 520 */ 521 static void unmap_vmap_area(struct vmap_area *va) 522 { 523 vunmap_page_range(va->va_start, va->va_end); 524 } 525 526 static void vmap_debug_free_range(unsigned long start, unsigned long end) 527 { 528 /* 529 * Unmap page tables and force a TLB flush immediately if 530 * CONFIG_DEBUG_PAGEALLOC is set. This catches use after free 531 * bugs similarly to those in linear kernel virtual address 532 * space after a page has been freed. 533 * 534 * All the lazy freeing logic is still retained, in order to 535 * minimise intrusiveness of this debugging feature. 536 * 537 * This is going to be *slow* (linear kernel virtual address 538 * debugging doesn't do a broadcast TLB flush so it is a lot 539 * faster). 540 */ 541 #ifdef CONFIG_DEBUG_PAGEALLOC 542 vunmap_page_range(start, end); 543 flush_tlb_kernel_range(start, end); 544 #endif 545 } 546 547 /* 548 * lazy_max_pages is the maximum amount of virtual address space we gather up 549 * before attempting to purge with a TLB flush. 550 * 551 * There is a tradeoff here: a larger number will cover more kernel page tables 552 * and take slightly longer to purge, but it will linearly reduce the number of 553 * global TLB flushes that must be performed. It would seem natural to scale 554 * this number up linearly with the number of CPUs (because vmapping activity 555 * could also scale linearly with the number of CPUs), however it is likely 556 * that in practice, workloads might be constrained in other ways that mean 557 * vmap activity will not scale linearly with CPUs. Also, I want to be 558 * conservative and not introduce a big latency on huge systems, so go with 559 * a less aggressive log scale. It will still be an improvement over the old 560 * code, and it will be simple to change the scale factor if we find that it 561 * becomes a problem on bigger systems. 562 */ 563 static unsigned long lazy_max_pages(void) 564 { 565 unsigned int log; 566 567 log = fls(num_online_cpus()); 568 569 return log * (32UL * 1024 * 1024 / PAGE_SIZE); 570 } 571 572 static atomic_t vmap_lazy_nr = ATOMIC_INIT(0); 573 574 /* for per-CPU blocks */ 575 static void purge_fragmented_blocks_allcpus(void); 576 577 /* 578 * called before a call to iounmap() if the caller wants vm_area_struct's 579 * immediately freed. 580 */ 581 void set_iounmap_nonlazy(void) 582 { 583 atomic_set(&vmap_lazy_nr, lazy_max_pages()+1); 584 } 585 586 /* 587 * Purges all lazily-freed vmap areas. 588 * 589 * If sync is 0 then don't purge if there is already a purge in progress. 590 * If force_flush is 1, then flush kernel TLBs between *start and *end even 591 * if we found no lazy vmap areas to unmap (callers can use this to optimise 592 * their own TLB flushing). 593 * Returns with *start = min(*start, lowest purged address) 594 * *end = max(*end, highest purged address) 595 */ 596 static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, 597 int sync, int force_flush) 598 { 599 static DEFINE_SPINLOCK(purge_lock); 600 LIST_HEAD(valist); 601 struct vmap_area *va; 602 struct vmap_area *n_va; 603 int nr = 0; 604 605 /* 606 * If sync is 0 but force_flush is 1, we'll go sync anyway but callers 607 * should not expect such behaviour. This just simplifies locking for 608 * the case that isn't actually used at the moment anyway. 609 */ 610 if (!sync && !force_flush) { 611 if (!spin_trylock(&purge_lock)) 612 return; 613 } else 614 spin_lock(&purge_lock); 615 616 if (sync) 617 purge_fragmented_blocks_allcpus(); 618 619 rcu_read_lock(); 620 list_for_each_entry_rcu(va, &vmap_area_list, list) { 621 if (va->flags & VM_LAZY_FREE) { 622 if (va->va_start < *start) 623 *start = va->va_start; 624 if (va->va_end > *end) 625 *end = va->va_end; 626 nr += (va->va_end - va->va_start) >> PAGE_SHIFT; 627 list_add_tail(&va->purge_list, &valist); 628 va->flags |= VM_LAZY_FREEING; 629 va->flags &= ~VM_LAZY_FREE; 630 } 631 } 632 rcu_read_unlock(); 633 634 if (nr) 635 atomic_sub(nr, &vmap_lazy_nr); 636 637 if (nr || force_flush) 638 flush_tlb_kernel_range(*start, *end); 639 640 if (nr) { 641 spin_lock(&vmap_area_lock); 642 list_for_each_entry_safe(va, n_va, &valist, purge_list) 643 __free_vmap_area(va); 644 spin_unlock(&vmap_area_lock); 645 } 646 spin_unlock(&purge_lock); 647 } 648 649 /* 650 * Kick off a purge of the outstanding lazy areas. Don't bother if somebody 651 * is already purging. 652 */ 653 static void try_purge_vmap_area_lazy(void) 654 { 655 unsigned long start = ULONG_MAX, end = 0; 656 657 __purge_vmap_area_lazy(&start, &end, 0, 0); 658 } 659 660 /* 661 * Kick off a purge of the outstanding lazy areas. 662 */ 663 static void purge_vmap_area_lazy(void) 664 { 665 unsigned long start = ULONG_MAX, end = 0; 666 667 __purge_vmap_area_lazy(&start, &end, 1, 0); 668 } 669 670 /* 671 * Free a vmap area, caller ensuring that the area has been unmapped 672 * and flush_cache_vunmap had been called for the correct range 673 * previously. 674 */ 675 static void free_vmap_area_noflush(struct vmap_area *va) 676 { 677 va->flags |= VM_LAZY_FREE; 678 atomic_add((va->va_end - va->va_start) >> PAGE_SHIFT, &vmap_lazy_nr); 679 if (unlikely(atomic_read(&vmap_lazy_nr) > lazy_max_pages())) 680 try_purge_vmap_area_lazy(); 681 } 682 683 /* 684 * Free and unmap a vmap area, caller ensuring flush_cache_vunmap had been 685 * called for the correct range previously. 686 */ 687 static void free_unmap_vmap_area_noflush(struct vmap_area *va) 688 { 689 unmap_vmap_area(va); 690 free_vmap_area_noflush(va); 691 } 692 693 /* 694 * Free and unmap a vmap area 695 */ 696 static void free_unmap_vmap_area(struct vmap_area *va) 697 { 698 flush_cache_vunmap(va->va_start, va->va_end); 699 free_unmap_vmap_area_noflush(va); 700 } 701 702 static struct vmap_area *find_vmap_area(unsigned long addr) 703 { 704 struct vmap_area *va; 705 706 spin_lock(&vmap_area_lock); 707 va = __find_vmap_area(addr); 708 spin_unlock(&vmap_area_lock); 709 710 return va; 711 } 712 713 static void free_unmap_vmap_area_addr(unsigned long addr) 714 { 715 struct vmap_area *va; 716 717 va = find_vmap_area(addr); 718 BUG_ON(!va); 719 free_unmap_vmap_area(va); 720 } 721 722 723 /*** Per cpu kva allocator ***/ 724 725 /* 726 * vmap space is limited especially on 32 bit architectures. Ensure there is 727 * room for at least 16 percpu vmap blocks per CPU. 728 */ 729 /* 730 * If we had a constant VMALLOC_START and VMALLOC_END, we'd like to be able 731 * to #define VMALLOC_SPACE (VMALLOC_END-VMALLOC_START). Guess 732 * instead (we just need a rough idea) 733 */ 734 #if BITS_PER_LONG == 32 735 #define VMALLOC_SPACE (128UL*1024*1024) 736 #else 737 #define VMALLOC_SPACE (128UL*1024*1024*1024) 738 #endif 739 740 #define VMALLOC_PAGES (VMALLOC_SPACE / PAGE_SIZE) 741 #define VMAP_MAX_ALLOC BITS_PER_LONG /* 256K with 4K pages */ 742 #define VMAP_BBMAP_BITS_MAX 1024 /* 4MB with 4K pages */ 743 #define VMAP_BBMAP_BITS_MIN (VMAP_MAX_ALLOC*2) 744 #define VMAP_MIN(x, y) ((x) < (y) ? (x) : (y)) /* can't use min() */ 745 #define VMAP_MAX(x, y) ((x) > (y) ? (x) : (y)) /* can't use max() */ 746 #define VMAP_BBMAP_BITS \ 747 VMAP_MIN(VMAP_BBMAP_BITS_MAX, \ 748 VMAP_MAX(VMAP_BBMAP_BITS_MIN, \ 749 VMALLOC_PAGES / roundup_pow_of_two(NR_CPUS) / 16)) 750 751 #define VMAP_BLOCK_SIZE (VMAP_BBMAP_BITS * PAGE_SIZE) 752 753 static bool vmap_initialized __read_mostly = false; 754 755 struct vmap_block_queue { 756 spinlock_t lock; 757 struct list_head free; 758 }; 759 760 struct vmap_block { 761 spinlock_t lock; 762 struct vmap_area *va; 763 unsigned long free, dirty; 764 DECLARE_BITMAP(dirty_map, VMAP_BBMAP_BITS); 765 struct list_head free_list; 766 struct rcu_head rcu_head; 767 struct list_head purge; 768 }; 769 770 /* Queue of free and dirty vmap blocks, for allocation and flushing purposes */ 771 static DEFINE_PER_CPU(struct vmap_block_queue, vmap_block_queue); 772 773 /* 774 * Radix tree of vmap blocks, indexed by address, to quickly find a vmap block 775 * in the free path. Could get rid of this if we change the API to return a 776 * "cookie" from alloc, to be passed to free. But no big deal yet. 777 */ 778 static DEFINE_SPINLOCK(vmap_block_tree_lock); 779 static RADIX_TREE(vmap_block_tree, GFP_ATOMIC); 780 781 /* 782 * We should probably have a fallback mechanism to allocate virtual memory 783 * out of partially filled vmap blocks. However vmap block sizing should be 784 * fairly reasonable according to the vmalloc size, so it shouldn't be a 785 * big problem. 786 */ 787 788 static unsigned long addr_to_vb_idx(unsigned long addr) 789 { 790 addr -= VMALLOC_START & ~(VMAP_BLOCK_SIZE-1); 791 addr /= VMAP_BLOCK_SIZE; 792 return addr; 793 } 794 795 static struct vmap_block *new_vmap_block(gfp_t gfp_mask) 796 { 797 struct vmap_block_queue *vbq; 798 struct vmap_block *vb; 799 struct vmap_area *va; 800 unsigned long vb_idx; 801 int node, err; 802 803 node = numa_node_id(); 804 805 vb = kmalloc_node(sizeof(struct vmap_block), 806 gfp_mask & GFP_RECLAIM_MASK, node); 807 if (unlikely(!vb)) 808 return ERR_PTR(-ENOMEM); 809 810 va = alloc_vmap_area(VMAP_BLOCK_SIZE, VMAP_BLOCK_SIZE, 811 VMALLOC_START, VMALLOC_END, 812 node, gfp_mask); 813 if (IS_ERR(va)) { 814 kfree(vb); 815 return ERR_CAST(va); 816 } 817 818 err = radix_tree_preload(gfp_mask); 819 if (unlikely(err)) { 820 kfree(vb); 821 free_vmap_area(va); 822 return ERR_PTR(err); 823 } 824 825 spin_lock_init(&vb->lock); 826 vb->va = va; 827 vb->free = VMAP_BBMAP_BITS; 828 vb->dirty = 0; 829 bitmap_zero(vb->dirty_map, VMAP_BBMAP_BITS); 830 INIT_LIST_HEAD(&vb->free_list); 831 832 vb_idx = addr_to_vb_idx(va->va_start); 833 spin_lock(&vmap_block_tree_lock); 834 err = radix_tree_insert(&vmap_block_tree, vb_idx, vb); 835 spin_unlock(&vmap_block_tree_lock); 836 BUG_ON(err); 837 radix_tree_preload_end(); 838 839 vbq = &get_cpu_var(vmap_block_queue); 840 spin_lock(&vbq->lock); 841 list_add_rcu(&vb->free_list, &vbq->free); 842 spin_unlock(&vbq->lock); 843 put_cpu_var(vmap_block_queue); 844 845 return vb; 846 } 847 848 static void free_vmap_block(struct vmap_block *vb) 849 { 850 struct vmap_block *tmp; 851 unsigned long vb_idx; 852 853 vb_idx = addr_to_vb_idx(vb->va->va_start); 854 spin_lock(&vmap_block_tree_lock); 855 tmp = radix_tree_delete(&vmap_block_tree, vb_idx); 856 spin_unlock(&vmap_block_tree_lock); 857 BUG_ON(tmp != vb); 858 859 free_vmap_area_noflush(vb->va); 860 kfree_rcu(vb, rcu_head); 861 } 862 863 static void purge_fragmented_blocks(int cpu) 864 { 865 LIST_HEAD(purge); 866 struct vmap_block *vb; 867 struct vmap_block *n_vb; 868 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu); 869 870 rcu_read_lock(); 871 list_for_each_entry_rcu(vb, &vbq->free, free_list) { 872 873 if (!(vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS)) 874 continue; 875 876 spin_lock(&vb->lock); 877 if (vb->free + vb->dirty == VMAP_BBMAP_BITS && vb->dirty != VMAP_BBMAP_BITS) { 878 vb->free = 0; /* prevent further allocs after releasing lock */ 879 vb->dirty = VMAP_BBMAP_BITS; /* prevent purging it again */ 880 bitmap_fill(vb->dirty_map, VMAP_BBMAP_BITS); 881 spin_lock(&vbq->lock); 882 list_del_rcu(&vb->free_list); 883 spin_unlock(&vbq->lock); 884 spin_unlock(&vb->lock); 885 list_add_tail(&vb->purge, &purge); 886 } else 887 spin_unlock(&vb->lock); 888 } 889 rcu_read_unlock(); 890 891 list_for_each_entry_safe(vb, n_vb, &purge, purge) { 892 list_del(&vb->purge); 893 free_vmap_block(vb); 894 } 895 } 896 897 static void purge_fragmented_blocks_allcpus(void) 898 { 899 int cpu; 900 901 for_each_possible_cpu(cpu) 902 purge_fragmented_blocks(cpu); 903 } 904 905 static void *vb_alloc(unsigned long size, gfp_t gfp_mask) 906 { 907 struct vmap_block_queue *vbq; 908 struct vmap_block *vb; 909 unsigned long addr = 0; 910 unsigned int order; 911 912 BUG_ON(size & ~PAGE_MASK); 913 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC); 914 if (WARN_ON(size == 0)) { 915 /* 916 * Allocating 0 bytes isn't what caller wants since 917 * get_order(0) returns funny result. Just warn and terminate 918 * early. 919 */ 920 return NULL; 921 } 922 order = get_order(size); 923 924 again: 925 rcu_read_lock(); 926 vbq = &get_cpu_var(vmap_block_queue); 927 list_for_each_entry_rcu(vb, &vbq->free, free_list) { 928 int i; 929 930 spin_lock(&vb->lock); 931 if (vb->free < 1UL << order) 932 goto next; 933 934 i = VMAP_BBMAP_BITS - vb->free; 935 addr = vb->va->va_start + (i << PAGE_SHIFT); 936 BUG_ON(addr_to_vb_idx(addr) != 937 addr_to_vb_idx(vb->va->va_start)); 938 vb->free -= 1UL << order; 939 if (vb->free == 0) { 940 spin_lock(&vbq->lock); 941 list_del_rcu(&vb->free_list); 942 spin_unlock(&vbq->lock); 943 } 944 spin_unlock(&vb->lock); 945 break; 946 next: 947 spin_unlock(&vb->lock); 948 } 949 950 put_cpu_var(vmap_block_queue); 951 rcu_read_unlock(); 952 953 if (!addr) { 954 vb = new_vmap_block(gfp_mask); 955 if (IS_ERR(vb)) 956 return vb; 957 goto again; 958 } 959 960 return (void *)addr; 961 } 962 963 static void vb_free(const void *addr, unsigned long size) 964 { 965 unsigned long offset; 966 unsigned long vb_idx; 967 unsigned int order; 968 struct vmap_block *vb; 969 970 BUG_ON(size & ~PAGE_MASK); 971 BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC); 972 973 flush_cache_vunmap((unsigned long)addr, (unsigned long)addr + size); 974 975 order = get_order(size); 976 977 offset = (unsigned long)addr & (VMAP_BLOCK_SIZE - 1); 978 979 vb_idx = addr_to_vb_idx((unsigned long)addr); 980 rcu_read_lock(); 981 vb = radix_tree_lookup(&vmap_block_tree, vb_idx); 982 rcu_read_unlock(); 983 BUG_ON(!vb); 984 985 vunmap_page_range((unsigned long)addr, (unsigned long)addr + size); 986 987 spin_lock(&vb->lock); 988 BUG_ON(bitmap_allocate_region(vb->dirty_map, offset >> PAGE_SHIFT, order)); 989 990 vb->dirty += 1UL << order; 991 if (vb->dirty == VMAP_BBMAP_BITS) { 992 BUG_ON(vb->free); 993 spin_unlock(&vb->lock); 994 free_vmap_block(vb); 995 } else 996 spin_unlock(&vb->lock); 997 } 998 999 /** 1000 * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer 1001 * 1002 * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily 1003 * to amortize TLB flushing overheads. What this means is that any page you 1004 * have now, may, in a former life, have been mapped into kernel virtual 1005 * address by the vmap layer and so there might be some CPUs with TLB entries 1006 * still referencing that page (additional to the regular 1:1 kernel mapping). 1007 * 1008 * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can 1009 * be sure that none of the pages we have control over will have any aliases 1010 * from the vmap layer. 1011 */ 1012 void vm_unmap_aliases(void) 1013 { 1014 unsigned long start = ULONG_MAX, end = 0; 1015 int cpu; 1016 int flush = 0; 1017 1018 if (unlikely(!vmap_initialized)) 1019 return; 1020 1021 for_each_possible_cpu(cpu) { 1022 struct vmap_block_queue *vbq = &per_cpu(vmap_block_queue, cpu); 1023 struct vmap_block *vb; 1024 1025 rcu_read_lock(); 1026 list_for_each_entry_rcu(vb, &vbq->free, free_list) { 1027 int i, j; 1028 1029 spin_lock(&vb->lock); 1030 i = find_first_bit(vb->dirty_map, VMAP_BBMAP_BITS); 1031 if (i < VMAP_BBMAP_BITS) { 1032 unsigned long s, e; 1033 1034 j = find_last_bit(vb->dirty_map, 1035 VMAP_BBMAP_BITS); 1036 j = j + 1; /* need exclusive index */ 1037 1038 s = vb->va->va_start + (i << PAGE_SHIFT); 1039 e = vb->va->va_start + (j << PAGE_SHIFT); 1040 flush = 1; 1041 1042 if (s < start) 1043 start = s; 1044 if (e > end) 1045 end = e; 1046 } 1047 spin_unlock(&vb->lock); 1048 } 1049 rcu_read_unlock(); 1050 } 1051 1052 __purge_vmap_area_lazy(&start, &end, 1, flush); 1053 } 1054 EXPORT_SYMBOL_GPL(vm_unmap_aliases); 1055 1056 /** 1057 * vm_unmap_ram - unmap linear kernel address space set up by vm_map_ram 1058 * @mem: the pointer returned by vm_map_ram 1059 * @count: the count passed to that vm_map_ram call (cannot unmap partial) 1060 */ 1061 void vm_unmap_ram(const void *mem, unsigned int count) 1062 { 1063 unsigned long size = count << PAGE_SHIFT; 1064 unsigned long addr = (unsigned long)mem; 1065 1066 BUG_ON(!addr); 1067 BUG_ON(addr < VMALLOC_START); 1068 BUG_ON(addr > VMALLOC_END); 1069 BUG_ON(addr & (PAGE_SIZE-1)); 1070 1071 debug_check_no_locks_freed(mem, size); 1072 vmap_debug_free_range(addr, addr+size); 1073 1074 if (likely(count <= VMAP_MAX_ALLOC)) 1075 vb_free(mem, size); 1076 else 1077 free_unmap_vmap_area_addr(addr); 1078 } 1079 EXPORT_SYMBOL(vm_unmap_ram); 1080 1081 /** 1082 * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space) 1083 * @pages: an array of pointers to the pages to be mapped 1084 * @count: number of pages 1085 * @node: prefer to allocate data structures on this node 1086 * @prot: memory protection to use. PAGE_KERNEL for regular RAM 1087 * 1088 * If you use this function for less than VMAP_MAX_ALLOC pages, it could be 1089 * faster than vmap so it's good. But if you mix long-life and short-life 1090 * objects with vm_map_ram(), it could consume lots of address space through 1091 * fragmentation (especially on a 32bit machine). You could see failures in 1092 * the end. Please use this function for short-lived objects. 1093 * 1094 * Returns: a pointer to the address that has been mapped, or %NULL on failure 1095 */ 1096 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot) 1097 { 1098 unsigned long size = count << PAGE_SHIFT; 1099 unsigned long addr; 1100 void *mem; 1101 1102 if (likely(count <= VMAP_MAX_ALLOC)) { 1103 mem = vb_alloc(size, GFP_KERNEL); 1104 if (IS_ERR(mem)) 1105 return NULL; 1106 addr = (unsigned long)mem; 1107 } else { 1108 struct vmap_area *va; 1109 va = alloc_vmap_area(size, PAGE_SIZE, 1110 VMALLOC_START, VMALLOC_END, node, GFP_KERNEL); 1111 if (IS_ERR(va)) 1112 return NULL; 1113 1114 addr = va->va_start; 1115 mem = (void *)addr; 1116 } 1117 if (vmap_page_range(addr, addr + size, prot, pages) < 0) { 1118 vm_unmap_ram(mem, count); 1119 return NULL; 1120 } 1121 return mem; 1122 } 1123 EXPORT_SYMBOL(vm_map_ram); 1124 1125 static struct vm_struct *vmlist __initdata; 1126 /** 1127 * vm_area_add_early - add vmap area early during boot 1128 * @vm: vm_struct to add 1129 * 1130 * This function is used to add fixed kernel vm area to vmlist before 1131 * vmalloc_init() is called. @vm->addr, @vm->size, and @vm->flags 1132 * should contain proper values and the other fields should be zero. 1133 * 1134 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING. 1135 */ 1136 void __init vm_area_add_early(struct vm_struct *vm) 1137 { 1138 struct vm_struct *tmp, **p; 1139 1140 BUG_ON(vmap_initialized); 1141 for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) { 1142 if (tmp->addr >= vm->addr) { 1143 BUG_ON(tmp->addr < vm->addr + vm->size); 1144 break; 1145 } else 1146 BUG_ON(tmp->addr + tmp->size > vm->addr); 1147 } 1148 vm->next = *p; 1149 *p = vm; 1150 } 1151 1152 /** 1153 * vm_area_register_early - register vmap area early during boot 1154 * @vm: vm_struct to register 1155 * @align: requested alignment 1156 * 1157 * This function is used to register kernel vm area before 1158 * vmalloc_init() is called. @vm->size and @vm->flags should contain 1159 * proper values on entry and other fields should be zero. On return, 1160 * vm->addr contains the allocated address. 1161 * 1162 * DO NOT USE THIS FUNCTION UNLESS YOU KNOW WHAT YOU'RE DOING. 1163 */ 1164 void __init vm_area_register_early(struct vm_struct *vm, size_t align) 1165 { 1166 static size_t vm_init_off __initdata; 1167 unsigned long addr; 1168 1169 addr = ALIGN(VMALLOC_START + vm_init_off, align); 1170 vm_init_off = PFN_ALIGN(addr + vm->size) - VMALLOC_START; 1171 1172 vm->addr = (void *)addr; 1173 1174 vm_area_add_early(vm); 1175 } 1176 1177 void __init vmalloc_init(void) 1178 { 1179 struct vmap_area *va; 1180 struct vm_struct *tmp; 1181 int i; 1182 1183 for_each_possible_cpu(i) { 1184 struct vmap_block_queue *vbq; 1185 struct vfree_deferred *p; 1186 1187 vbq = &per_cpu(vmap_block_queue, i); 1188 spin_lock_init(&vbq->lock); 1189 INIT_LIST_HEAD(&vbq->free); 1190 p = &per_cpu(vfree_deferred, i); 1191 init_llist_head(&p->list); 1192 INIT_WORK(&p->wq, free_work); 1193 } 1194 1195 /* Import existing vmlist entries. */ 1196 for (tmp = vmlist; tmp; tmp = tmp->next) { 1197 va = kzalloc(sizeof(struct vmap_area), GFP_NOWAIT); 1198 va->flags = VM_VM_AREA; 1199 va->va_start = (unsigned long)tmp->addr; 1200 va->va_end = va->va_start + tmp->size; 1201 va->vm = tmp; 1202 __insert_vmap_area(va); 1203 } 1204 1205 vmap_area_pcpu_hole = VMALLOC_END; 1206 1207 vmap_initialized = true; 1208 } 1209 1210 /** 1211 * map_kernel_range_noflush - map kernel VM area with the specified pages 1212 * @addr: start of the VM area to map 1213 * @size: size of the VM area to map 1214 * @prot: page protection flags to use 1215 * @pages: pages to map 1216 * 1217 * Map PFN_UP(@size) pages at @addr. The VM area @addr and @size 1218 * specify should have been allocated using get_vm_area() and its 1219 * friends. 1220 * 1221 * NOTE: 1222 * This function does NOT do any cache flushing. The caller is 1223 * responsible for calling flush_cache_vmap() on to-be-mapped areas 1224 * before calling this function. 1225 * 1226 * RETURNS: 1227 * The number of pages mapped on success, -errno on failure. 1228 */ 1229 int map_kernel_range_noflush(unsigned long addr, unsigned long size, 1230 pgprot_t prot, struct page **pages) 1231 { 1232 return vmap_page_range_noflush(addr, addr + size, prot, pages); 1233 } 1234 1235 /** 1236 * unmap_kernel_range_noflush - unmap kernel VM area 1237 * @addr: start of the VM area to unmap 1238 * @size: size of the VM area to unmap 1239 * 1240 * Unmap PFN_UP(@size) pages at @addr. The VM area @addr and @size 1241 * specify should have been allocated using get_vm_area() and its 1242 * friends. 1243 * 1244 * NOTE: 1245 * This function does NOT do any cache flushing. The caller is 1246 * responsible for calling flush_cache_vunmap() on to-be-mapped areas 1247 * before calling this function and flush_tlb_kernel_range() after. 1248 */ 1249 void unmap_kernel_range_noflush(unsigned long addr, unsigned long size) 1250 { 1251 vunmap_page_range(addr, addr + size); 1252 } 1253 EXPORT_SYMBOL_GPL(unmap_kernel_range_noflush); 1254 1255 /** 1256 * unmap_kernel_range - unmap kernel VM area and flush cache and TLB 1257 * @addr: start of the VM area to unmap 1258 * @size: size of the VM area to unmap 1259 * 1260 * Similar to unmap_kernel_range_noflush() but flushes vcache before 1261 * the unmapping and tlb after. 1262 */ 1263 void unmap_kernel_range(unsigned long addr, unsigned long size) 1264 { 1265 unsigned long end = addr + size; 1266 1267 flush_cache_vunmap(addr, end); 1268 vunmap_page_range(addr, end); 1269 flush_tlb_kernel_range(addr, end); 1270 } 1271 1272 int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages) 1273 { 1274 unsigned long addr = (unsigned long)area->addr; 1275 unsigned long end = addr + get_vm_area_size(area); 1276 int err; 1277 1278 err = vmap_page_range(addr, end, prot, *pages); 1279 if (err > 0) { 1280 *pages += err; 1281 err = 0; 1282 } 1283 1284 return err; 1285 } 1286 EXPORT_SYMBOL_GPL(map_vm_area); 1287 1288 static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, 1289 unsigned long flags, const void *caller) 1290 { 1291 spin_lock(&vmap_area_lock); 1292 vm->flags = flags; 1293 vm->addr = (void *)va->va_start; 1294 vm->size = va->va_end - va->va_start; 1295 vm->caller = caller; 1296 va->vm = vm; 1297 va->flags |= VM_VM_AREA; 1298 spin_unlock(&vmap_area_lock); 1299 } 1300 1301 static void clear_vm_uninitialized_flag(struct vm_struct *vm) 1302 { 1303 /* 1304 * Before removing VM_UNINITIALIZED, 1305 * we should make sure that vm has proper values. 1306 * Pair with smp_rmb() in show_numa_info(). 1307 */ 1308 smp_wmb(); 1309 vm->flags &= ~VM_UNINITIALIZED; 1310 } 1311 1312 static struct vm_struct *__get_vm_area_node(unsigned long size, 1313 unsigned long align, unsigned long flags, unsigned long start, 1314 unsigned long end, int node, gfp_t gfp_mask, const void *caller) 1315 { 1316 struct vmap_area *va; 1317 struct vm_struct *area; 1318 1319 BUG_ON(in_interrupt()); 1320 if (flags & VM_IOREMAP) 1321 align = 1ul << clamp(fls(size), PAGE_SHIFT, IOREMAP_MAX_ORDER); 1322 1323 size = PAGE_ALIGN(size); 1324 if (unlikely(!size)) 1325 return NULL; 1326 1327 area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node); 1328 if (unlikely(!area)) 1329 return NULL; 1330 1331 /* 1332 * We always allocate a guard page. 1333 */ 1334 size += PAGE_SIZE; 1335 1336 va = alloc_vmap_area(size, align, start, end, node, gfp_mask); 1337 if (IS_ERR(va)) { 1338 kfree(area); 1339 return NULL; 1340 } 1341 1342 setup_vmalloc_vm(area, va, flags, caller); 1343 1344 return area; 1345 } 1346 1347 struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags, 1348 unsigned long start, unsigned long end) 1349 { 1350 return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE, 1351 GFP_KERNEL, __builtin_return_address(0)); 1352 } 1353 EXPORT_SYMBOL_GPL(__get_vm_area); 1354 1355 struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags, 1356 unsigned long start, unsigned long end, 1357 const void *caller) 1358 { 1359 return __get_vm_area_node(size, 1, flags, start, end, NUMA_NO_NODE, 1360 GFP_KERNEL, caller); 1361 } 1362 1363 /** 1364 * get_vm_area - reserve a contiguous kernel virtual area 1365 * @size: size of the area 1366 * @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC 1367 * 1368 * Search an area of @size in the kernel virtual mapping area, 1369 * and reserved it for out purposes. Returns the area descriptor 1370 * on success or %NULL on failure. 1371 */ 1372 struct vm_struct *get_vm_area(unsigned long size, unsigned long flags) 1373 { 1374 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END, 1375 NUMA_NO_NODE, GFP_KERNEL, 1376 __builtin_return_address(0)); 1377 } 1378 1379 struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags, 1380 const void *caller) 1381 { 1382 return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END, 1383 NUMA_NO_NODE, GFP_KERNEL, caller); 1384 } 1385 1386 /** 1387 * find_vm_area - find a continuous kernel virtual area 1388 * @addr: base address 1389 * 1390 * Search for the kernel VM area starting at @addr, and return it. 1391 * It is up to the caller to do all required locking to keep the returned 1392 * pointer valid. 1393 */ 1394 struct vm_struct *find_vm_area(const void *addr) 1395 { 1396 struct vmap_area *va; 1397 1398 va = find_vmap_area((unsigned long)addr); 1399 if (va && va->flags & VM_VM_AREA) 1400 return va->vm; 1401 1402 return NULL; 1403 } 1404 1405 /** 1406 * remove_vm_area - find and remove a continuous kernel virtual area 1407 * @addr: base address 1408 * 1409 * Search for the kernel VM area starting at @addr, and remove it. 1410 * This function returns the found VM area, but using it is NOT safe 1411 * on SMP machines, except for its size or flags. 1412 */ 1413 struct vm_struct *remove_vm_area(const void *addr) 1414 { 1415 struct vmap_area *va; 1416 1417 va = find_vmap_area((unsigned long)addr); 1418 if (va && va->flags & VM_VM_AREA) { 1419 struct vm_struct *vm = va->vm; 1420 1421 spin_lock(&vmap_area_lock); 1422 va->vm = NULL; 1423 va->flags &= ~VM_VM_AREA; 1424 spin_unlock(&vmap_area_lock); 1425 1426 vmap_debug_free_range(va->va_start, va->va_end); 1427 free_unmap_vmap_area(va); 1428 vm->size -= PAGE_SIZE; 1429 1430 return vm; 1431 } 1432 return NULL; 1433 } 1434 1435 static void __vunmap(const void *addr, int deallocate_pages) 1436 { 1437 struct vm_struct *area; 1438 1439 if (!addr) 1440 return; 1441 1442 if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n", 1443 addr)) 1444 return; 1445 1446 area = remove_vm_area(addr); 1447 if (unlikely(!area)) { 1448 WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n", 1449 addr); 1450 return; 1451 } 1452 1453 debug_check_no_locks_freed(addr, area->size); 1454 debug_check_no_obj_freed(addr, area->size); 1455 1456 if (deallocate_pages) { 1457 int i; 1458 1459 for (i = 0; i < area->nr_pages; i++) { 1460 struct page *page = area->pages[i]; 1461 1462 BUG_ON(!page); 1463 __free_page(page); 1464 } 1465 1466 if (area->flags & VM_VPAGES) 1467 vfree(area->pages); 1468 else 1469 kfree(area->pages); 1470 } 1471 1472 kfree(area); 1473 return; 1474 } 1475 1476 /** 1477 * vfree - release memory allocated by vmalloc() 1478 * @addr: memory base address 1479 * 1480 * Free the virtually continuous memory area starting at @addr, as 1481 * obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is 1482 * NULL, no operation is performed. 1483 * 1484 * Must not be called in NMI context (strictly speaking, only if we don't 1485 * have CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, but making the calling 1486 * conventions for vfree() arch-depenedent would be a really bad idea) 1487 * 1488 * NOTE: assumes that the object at *addr has a size >= sizeof(llist_node) 1489 */ 1490 void vfree(const void *addr) 1491 { 1492 BUG_ON(in_nmi()); 1493 1494 kmemleak_free(addr); 1495 1496 if (!addr) 1497 return; 1498 if (unlikely(in_interrupt())) { 1499 struct vfree_deferred *p = &__get_cpu_var(vfree_deferred); 1500 if (llist_add((struct llist_node *)addr, &p->list)) 1501 schedule_work(&p->wq); 1502 } else 1503 __vunmap(addr, 1); 1504 } 1505 EXPORT_SYMBOL(vfree); 1506 1507 /** 1508 * vunmap - release virtual mapping obtained by vmap() 1509 * @addr: memory base address 1510 * 1511 * Free the virtually contiguous memory area starting at @addr, 1512 * which was created from the page array passed to vmap(). 1513 * 1514 * Must not be called in interrupt context. 1515 */ 1516 void vunmap(const void *addr) 1517 { 1518 BUG_ON(in_interrupt()); 1519 might_sleep(); 1520 if (addr) 1521 __vunmap(addr, 0); 1522 } 1523 EXPORT_SYMBOL(vunmap); 1524 1525 /** 1526 * vmap - map an array of pages into virtually contiguous space 1527 * @pages: array of page pointers 1528 * @count: number of pages to map 1529 * @flags: vm_area->flags 1530 * @prot: page protection for the mapping 1531 * 1532 * Maps @count pages from @pages into contiguous kernel virtual 1533 * space. 1534 */ 1535 void *vmap(struct page **pages, unsigned int count, 1536 unsigned long flags, pgprot_t prot) 1537 { 1538 struct vm_struct *area; 1539 1540 might_sleep(); 1541 1542 if (count > totalram_pages) 1543 return NULL; 1544 1545 area = get_vm_area_caller((count << PAGE_SHIFT), flags, 1546 __builtin_return_address(0)); 1547 if (!area) 1548 return NULL; 1549 1550 if (map_vm_area(area, prot, &pages)) { 1551 vunmap(area->addr); 1552 return NULL; 1553 } 1554 1555 return area->addr; 1556 } 1557 EXPORT_SYMBOL(vmap); 1558 1559 static void *__vmalloc_node(unsigned long size, unsigned long align, 1560 gfp_t gfp_mask, pgprot_t prot, 1561 int node, const void *caller); 1562 static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask, 1563 pgprot_t prot, int node) 1564 { 1565 const int order = 0; 1566 struct page **pages; 1567 unsigned int nr_pages, array_size, i; 1568 gfp_t nested_gfp = (gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO; 1569 1570 nr_pages = get_vm_area_size(area) >> PAGE_SHIFT; 1571 array_size = (nr_pages * sizeof(struct page *)); 1572 1573 area->nr_pages = nr_pages; 1574 /* Please note that the recursion is strictly bounded. */ 1575 if (array_size > PAGE_SIZE) { 1576 pages = __vmalloc_node(array_size, 1, nested_gfp|__GFP_HIGHMEM, 1577 PAGE_KERNEL, node, area->caller); 1578 area->flags |= VM_VPAGES; 1579 } else { 1580 pages = kmalloc_node(array_size, nested_gfp, node); 1581 } 1582 area->pages = pages; 1583 if (!area->pages) { 1584 remove_vm_area(area->addr); 1585 kfree(area); 1586 return NULL; 1587 } 1588 1589 for (i = 0; i < area->nr_pages; i++) { 1590 struct page *page; 1591 gfp_t tmp_mask = gfp_mask | __GFP_NOWARN; 1592 1593 if (node == NUMA_NO_NODE) 1594 page = alloc_page(tmp_mask); 1595 else 1596 page = alloc_pages_node(node, tmp_mask, order); 1597 1598 if (unlikely(!page)) { 1599 /* Successfully allocated i pages, free them in __vunmap() */ 1600 area->nr_pages = i; 1601 goto fail; 1602 } 1603 area->pages[i] = page; 1604 } 1605 1606 if (map_vm_area(area, prot, &pages)) 1607 goto fail; 1608 return area->addr; 1609 1610 fail: 1611 warn_alloc_failed(gfp_mask, order, 1612 "vmalloc: allocation failure, allocated %ld of %ld bytes\n", 1613 (area->nr_pages*PAGE_SIZE), area->size); 1614 vfree(area->addr); 1615 return NULL; 1616 } 1617 1618 /** 1619 * __vmalloc_node_range - allocate virtually contiguous memory 1620 * @size: allocation size 1621 * @align: desired alignment 1622 * @start: vm area range start 1623 * @end: vm area range end 1624 * @gfp_mask: flags for the page level allocator 1625 * @prot: protection mask for the allocated pages 1626 * @node: node to use for allocation or NUMA_NO_NODE 1627 * @caller: caller's return address 1628 * 1629 * Allocate enough pages to cover @size from the page level 1630 * allocator with @gfp_mask flags. Map them into contiguous 1631 * kernel virtual space, using a pagetable protection of @prot. 1632 */ 1633 void *__vmalloc_node_range(unsigned long size, unsigned long align, 1634 unsigned long start, unsigned long end, gfp_t gfp_mask, 1635 pgprot_t prot, int node, const void *caller) 1636 { 1637 struct vm_struct *area; 1638 void *addr; 1639 unsigned long real_size = size; 1640 1641 size = PAGE_ALIGN(size); 1642 if (!size || (size >> PAGE_SHIFT) > totalram_pages) 1643 goto fail; 1644 1645 area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNINITIALIZED, 1646 start, end, node, gfp_mask, caller); 1647 if (!area) 1648 goto fail; 1649 1650 addr = __vmalloc_area_node(area, gfp_mask, prot, node); 1651 if (!addr) 1652 return NULL; 1653 1654 /* 1655 * In this function, newly allocated vm_struct has VM_UNINITIALIZED 1656 * flag. It means that vm_struct is not fully initialized. 1657 * Now, it is fully initialized, so remove this flag here. 1658 */ 1659 clear_vm_uninitialized_flag(area); 1660 1661 /* 1662 * A ref_count = 2 is needed because vm_struct allocated in 1663 * __get_vm_area_node() contains a reference to the virtual address of 1664 * the vmalloc'ed block. 1665 */ 1666 kmemleak_alloc(addr, real_size, 2, gfp_mask); 1667 1668 return addr; 1669 1670 fail: 1671 warn_alloc_failed(gfp_mask, 0, 1672 "vmalloc: allocation failure: %lu bytes\n", 1673 real_size); 1674 return NULL; 1675 } 1676 1677 /** 1678 * __vmalloc_node - allocate virtually contiguous memory 1679 * @size: allocation size 1680 * @align: desired alignment 1681 * @gfp_mask: flags for the page level allocator 1682 * @prot: protection mask for the allocated pages 1683 * @node: node to use for allocation or NUMA_NO_NODE 1684 * @caller: caller's return address 1685 * 1686 * Allocate enough pages to cover @size from the page level 1687 * allocator with @gfp_mask flags. Map them into contiguous 1688 * kernel virtual space, using a pagetable protection of @prot. 1689 */ 1690 static void *__vmalloc_node(unsigned long size, unsigned long align, 1691 gfp_t gfp_mask, pgprot_t prot, 1692 int node, const void *caller) 1693 { 1694 return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END, 1695 gfp_mask, prot, node, caller); 1696 } 1697 1698 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) 1699 { 1700 return __vmalloc_node(size, 1, gfp_mask, prot, NUMA_NO_NODE, 1701 __builtin_return_address(0)); 1702 } 1703 EXPORT_SYMBOL(__vmalloc); 1704 1705 static inline void *__vmalloc_node_flags(unsigned long size, 1706 int node, gfp_t flags) 1707 { 1708 return __vmalloc_node(size, 1, flags, PAGE_KERNEL, 1709 node, __builtin_return_address(0)); 1710 } 1711 1712 /** 1713 * vmalloc - allocate virtually contiguous memory 1714 * @size: allocation size 1715 * Allocate enough pages to cover @size from the page level 1716 * allocator and map them into contiguous kernel virtual space. 1717 * 1718 * For tight control over page level allocator and protection flags 1719 * use __vmalloc() instead. 1720 */ 1721 void *vmalloc(unsigned long size) 1722 { 1723 return __vmalloc_node_flags(size, NUMA_NO_NODE, 1724 GFP_KERNEL | __GFP_HIGHMEM); 1725 } 1726 EXPORT_SYMBOL(vmalloc); 1727 1728 /** 1729 * vzalloc - allocate virtually contiguous memory with zero fill 1730 * @size: allocation size 1731 * Allocate enough pages to cover @size from the page level 1732 * allocator and map them into contiguous kernel virtual space. 1733 * The memory allocated is set to zero. 1734 * 1735 * For tight control over page level allocator and protection flags 1736 * use __vmalloc() instead. 1737 */ 1738 void *vzalloc(unsigned long size) 1739 { 1740 return __vmalloc_node_flags(size, NUMA_NO_NODE, 1741 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO); 1742 } 1743 EXPORT_SYMBOL(vzalloc); 1744 1745 /** 1746 * vmalloc_user - allocate zeroed virtually contiguous memory for userspace 1747 * @size: allocation size 1748 * 1749 * The resulting memory area is zeroed so it can be mapped to userspace 1750 * without leaking data. 1751 */ 1752 void *vmalloc_user(unsigned long size) 1753 { 1754 struct vm_struct *area; 1755 void *ret; 1756 1757 ret = __vmalloc_node(size, SHMLBA, 1758 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, 1759 PAGE_KERNEL, NUMA_NO_NODE, 1760 __builtin_return_address(0)); 1761 if (ret) { 1762 area = find_vm_area(ret); 1763 area->flags |= VM_USERMAP; 1764 } 1765 return ret; 1766 } 1767 EXPORT_SYMBOL(vmalloc_user); 1768 1769 /** 1770 * vmalloc_node - allocate memory on a specific node 1771 * @size: allocation size 1772 * @node: numa node 1773 * 1774 * Allocate enough pages to cover @size from the page level 1775 * allocator and map them into contiguous kernel virtual space. 1776 * 1777 * For tight control over page level allocator and protection flags 1778 * use __vmalloc() instead. 1779 */ 1780 void *vmalloc_node(unsigned long size, int node) 1781 { 1782 return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL, 1783 node, __builtin_return_address(0)); 1784 } 1785 EXPORT_SYMBOL(vmalloc_node); 1786 1787 /** 1788 * vzalloc_node - allocate memory on a specific node with zero fill 1789 * @size: allocation size 1790 * @node: numa node 1791 * 1792 * Allocate enough pages to cover @size from the page level 1793 * allocator and map them into contiguous kernel virtual space. 1794 * The memory allocated is set to zero. 1795 * 1796 * For tight control over page level allocator and protection flags 1797 * use __vmalloc_node() instead. 1798 */ 1799 void *vzalloc_node(unsigned long size, int node) 1800 { 1801 return __vmalloc_node_flags(size, node, 1802 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO); 1803 } 1804 EXPORT_SYMBOL(vzalloc_node); 1805 1806 #ifndef PAGE_KERNEL_EXEC 1807 # define PAGE_KERNEL_EXEC PAGE_KERNEL 1808 #endif 1809 1810 /** 1811 * vmalloc_exec - allocate virtually contiguous, executable memory 1812 * @size: allocation size 1813 * 1814 * Kernel-internal function to allocate enough pages to cover @size 1815 * the page level allocator and map them into contiguous and 1816 * executable kernel virtual space. 1817 * 1818 * For tight control over page level allocator and protection flags 1819 * use __vmalloc() instead. 1820 */ 1821 1822 void *vmalloc_exec(unsigned long size) 1823 { 1824 return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC, 1825 NUMA_NO_NODE, __builtin_return_address(0)); 1826 } 1827 1828 #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32) 1829 #define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL 1830 #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA) 1831 #define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL 1832 #else 1833 #define GFP_VMALLOC32 GFP_KERNEL 1834 #endif 1835 1836 /** 1837 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) 1838 * @size: allocation size 1839 * 1840 * Allocate enough 32bit PA addressable pages to cover @size from the 1841 * page level allocator and map them into contiguous kernel virtual space. 1842 */ 1843 void *vmalloc_32(unsigned long size) 1844 { 1845 return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL, 1846 NUMA_NO_NODE, __builtin_return_address(0)); 1847 } 1848 EXPORT_SYMBOL(vmalloc_32); 1849 1850 /** 1851 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory 1852 * @size: allocation size 1853 * 1854 * The resulting memory area is 32bit addressable and zeroed so it can be 1855 * mapped to userspace without leaking data. 1856 */ 1857 void *vmalloc_32_user(unsigned long size) 1858 { 1859 struct vm_struct *area; 1860 void *ret; 1861 1862 ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL, 1863 NUMA_NO_NODE, __builtin_return_address(0)); 1864 if (ret) { 1865 area = find_vm_area(ret); 1866 area->flags |= VM_USERMAP; 1867 } 1868 return ret; 1869 } 1870 EXPORT_SYMBOL(vmalloc_32_user); 1871 1872 /* 1873 * small helper routine , copy contents to buf from addr. 1874 * If the page is not present, fill zero. 1875 */ 1876 1877 static int aligned_vread(char *buf, char *addr, unsigned long count) 1878 { 1879 struct page *p; 1880 int copied = 0; 1881 1882 while (count) { 1883 unsigned long offset, length; 1884 1885 offset = (unsigned long)addr & ~PAGE_MASK; 1886 length = PAGE_SIZE - offset; 1887 if (length > count) 1888 length = count; 1889 p = vmalloc_to_page(addr); 1890 /* 1891 * To do safe access to this _mapped_ area, we need 1892 * lock. But adding lock here means that we need to add 1893 * overhead of vmalloc()/vfree() calles for this _debug_ 1894 * interface, rarely used. Instead of that, we'll use 1895 * kmap() and get small overhead in this access function. 1896 */ 1897 if (p) { 1898 /* 1899 * we can expect USER0 is not used (see vread/vwrite's 1900 * function description) 1901 */ 1902 void *map = kmap_atomic(p); 1903 memcpy(buf, map + offset, length); 1904 kunmap_atomic(map); 1905 } else 1906 memset(buf, 0, length); 1907 1908 addr += length; 1909 buf += length; 1910 copied += length; 1911 count -= length; 1912 } 1913 return copied; 1914 } 1915 1916 static int aligned_vwrite(char *buf, char *addr, unsigned long count) 1917 { 1918 struct page *p; 1919 int copied = 0; 1920 1921 while (count) { 1922 unsigned long offset, length; 1923 1924 offset = (unsigned long)addr & ~PAGE_MASK; 1925 length = PAGE_SIZE - offset; 1926 if (length > count) 1927 length = count; 1928 p = vmalloc_to_page(addr); 1929 /* 1930 * To do safe access to this _mapped_ area, we need 1931 * lock. But adding lock here means that we need to add 1932 * overhead of vmalloc()/vfree() calles for this _debug_ 1933 * interface, rarely used. Instead of that, we'll use 1934 * kmap() and get small overhead in this access function. 1935 */ 1936 if (p) { 1937 /* 1938 * we can expect USER0 is not used (see vread/vwrite's 1939 * function description) 1940 */ 1941 void *map = kmap_atomic(p); 1942 memcpy(map + offset, buf, length); 1943 kunmap_atomic(map); 1944 } 1945 addr += length; 1946 buf += length; 1947 copied += length; 1948 count -= length; 1949 } 1950 return copied; 1951 } 1952 1953 /** 1954 * vread() - read vmalloc area in a safe way. 1955 * @buf: buffer for reading data 1956 * @addr: vm address. 1957 * @count: number of bytes to be read. 1958 * 1959 * Returns # of bytes which addr and buf should be increased. 1960 * (same number to @count). Returns 0 if [addr...addr+count) doesn't 1961 * includes any intersect with alive vmalloc area. 1962 * 1963 * This function checks that addr is a valid vmalloc'ed area, and 1964 * copy data from that area to a given buffer. If the given memory range 1965 * of [addr...addr+count) includes some valid address, data is copied to 1966 * proper area of @buf. If there are memory holes, they'll be zero-filled. 1967 * IOREMAP area is treated as memory hole and no copy is done. 1968 * 1969 * If [addr...addr+count) doesn't includes any intersects with alive 1970 * vm_struct area, returns 0. @buf should be kernel's buffer. 1971 * 1972 * Note: In usual ops, vread() is never necessary because the caller 1973 * should know vmalloc() area is valid and can use memcpy(). 1974 * This is for routines which have to access vmalloc area without 1975 * any informaion, as /dev/kmem. 1976 * 1977 */ 1978 1979 long vread(char *buf, char *addr, unsigned long count) 1980 { 1981 struct vmap_area *va; 1982 struct vm_struct *vm; 1983 char *vaddr, *buf_start = buf; 1984 unsigned long buflen = count; 1985 unsigned long n; 1986 1987 /* Don't allow overflow */ 1988 if ((unsigned long) addr + count < count) 1989 count = -(unsigned long) addr; 1990 1991 spin_lock(&vmap_area_lock); 1992 list_for_each_entry(va, &vmap_area_list, list) { 1993 if (!count) 1994 break; 1995 1996 if (!(va->flags & VM_VM_AREA)) 1997 continue; 1998 1999 vm = va->vm; 2000 vaddr = (char *) vm->addr; 2001 if (addr >= vaddr + get_vm_area_size(vm)) 2002 continue; 2003 while (addr < vaddr) { 2004 if (count == 0) 2005 goto finished; 2006 *buf = '\0'; 2007 buf++; 2008 addr++; 2009 count--; 2010 } 2011 n = vaddr + get_vm_area_size(vm) - addr; 2012 if (n > count) 2013 n = count; 2014 if (!(vm->flags & VM_IOREMAP)) 2015 aligned_vread(buf, addr, n); 2016 else /* IOREMAP area is treated as memory hole */ 2017 memset(buf, 0, n); 2018 buf += n; 2019 addr += n; 2020 count -= n; 2021 } 2022 finished: 2023 spin_unlock(&vmap_area_lock); 2024 2025 if (buf == buf_start) 2026 return 0; 2027 /* zero-fill memory holes */ 2028 if (buf != buf_start + buflen) 2029 memset(buf, 0, buflen - (buf - buf_start)); 2030 2031 return buflen; 2032 } 2033 2034 /** 2035 * vwrite() - write vmalloc area in a safe way. 2036 * @buf: buffer for source data 2037 * @addr: vm address. 2038 * @count: number of bytes to be read. 2039 * 2040 * Returns # of bytes which addr and buf should be incresed. 2041 * (same number to @count). 2042 * If [addr...addr+count) doesn't includes any intersect with valid 2043 * vmalloc area, returns 0. 2044 * 2045 * This function checks that addr is a valid vmalloc'ed area, and 2046 * copy data from a buffer to the given addr. If specified range of 2047 * [addr...addr+count) includes some valid address, data is copied from 2048 * proper area of @buf. If there are memory holes, no copy to hole. 2049 * IOREMAP area is treated as memory hole and no copy is done. 2050 * 2051 * If [addr...addr+count) doesn't includes any intersects with alive 2052 * vm_struct area, returns 0. @buf should be kernel's buffer. 2053 * 2054 * Note: In usual ops, vwrite() is never necessary because the caller 2055 * should know vmalloc() area is valid and can use memcpy(). 2056 * This is for routines which have to access vmalloc area without 2057 * any informaion, as /dev/kmem. 2058 */ 2059 2060 long vwrite(char *buf, char *addr, unsigned long count) 2061 { 2062 struct vmap_area *va; 2063 struct vm_struct *vm; 2064 char *vaddr; 2065 unsigned long n, buflen; 2066 int copied = 0; 2067 2068 /* Don't allow overflow */ 2069 if ((unsigned long) addr + count < count) 2070 count = -(unsigned long) addr; 2071 buflen = count; 2072 2073 spin_lock(&vmap_area_lock); 2074 list_for_each_entry(va, &vmap_area_list, list) { 2075 if (!count) 2076 break; 2077 2078 if (!(va->flags & VM_VM_AREA)) 2079 continue; 2080 2081 vm = va->vm; 2082 vaddr = (char *) vm->addr; 2083 if (addr >= vaddr + get_vm_area_size(vm)) 2084 continue; 2085 while (addr < vaddr) { 2086 if (count == 0) 2087 goto finished; 2088 buf++; 2089 addr++; 2090 count--; 2091 } 2092 n = vaddr + get_vm_area_size(vm) - addr; 2093 if (n > count) 2094 n = count; 2095 if (!(vm->flags & VM_IOREMAP)) { 2096 aligned_vwrite(buf, addr, n); 2097 copied++; 2098 } 2099 buf += n; 2100 addr += n; 2101 count -= n; 2102 } 2103 finished: 2104 spin_unlock(&vmap_area_lock); 2105 if (!copied) 2106 return 0; 2107 return buflen; 2108 } 2109 2110 /** 2111 * remap_vmalloc_range_partial - map vmalloc pages to userspace 2112 * @vma: vma to cover 2113 * @uaddr: target user address to start at 2114 * @kaddr: virtual address of vmalloc kernel memory 2115 * @size: size of map area 2116 * 2117 * Returns: 0 for success, -Exxx on failure 2118 * 2119 * This function checks that @kaddr is a valid vmalloc'ed area, 2120 * and that it is big enough to cover the range starting at 2121 * @uaddr in @vma. Will return failure if that criteria isn't 2122 * met. 2123 * 2124 * Similar to remap_pfn_range() (see mm/memory.c) 2125 */ 2126 int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr, 2127 void *kaddr, unsigned long size) 2128 { 2129 struct vm_struct *area; 2130 2131 size = PAGE_ALIGN(size); 2132 2133 if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr)) 2134 return -EINVAL; 2135 2136 area = find_vm_area(kaddr); 2137 if (!area) 2138 return -EINVAL; 2139 2140 if (!(area->flags & VM_USERMAP)) 2141 return -EINVAL; 2142 2143 if (kaddr + size > area->addr + area->size) 2144 return -EINVAL; 2145 2146 do { 2147 struct page *page = vmalloc_to_page(kaddr); 2148 int ret; 2149 2150 ret = vm_insert_page(vma, uaddr, page); 2151 if (ret) 2152 return ret; 2153 2154 uaddr += PAGE_SIZE; 2155 kaddr += PAGE_SIZE; 2156 size -= PAGE_SIZE; 2157 } while (size > 0); 2158 2159 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 2160 2161 return 0; 2162 } 2163 EXPORT_SYMBOL(remap_vmalloc_range_partial); 2164 2165 /** 2166 * remap_vmalloc_range - map vmalloc pages to userspace 2167 * @vma: vma to cover (map full range of vma) 2168 * @addr: vmalloc memory 2169 * @pgoff: number of pages into addr before first page to map 2170 * 2171 * Returns: 0 for success, -Exxx on failure 2172 * 2173 * This function checks that addr is a valid vmalloc'ed area, and 2174 * that it is big enough to cover the vma. Will return failure if 2175 * that criteria isn't met. 2176 * 2177 * Similar to remap_pfn_range() (see mm/memory.c) 2178 */ 2179 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, 2180 unsigned long pgoff) 2181 { 2182 return remap_vmalloc_range_partial(vma, vma->vm_start, 2183 addr + (pgoff << PAGE_SHIFT), 2184 vma->vm_end - vma->vm_start); 2185 } 2186 EXPORT_SYMBOL(remap_vmalloc_range); 2187 2188 /* 2189 * Implement a stub for vmalloc_sync_all() if the architecture chose not to 2190 * have one. 2191 */ 2192 void __weak vmalloc_sync_all(void) 2193 { 2194 } 2195 2196 2197 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data) 2198 { 2199 pte_t ***p = data; 2200 2201 if (p) { 2202 *(*p) = pte; 2203 (*p)++; 2204 } 2205 return 0; 2206 } 2207 2208 /** 2209 * alloc_vm_area - allocate a range of kernel address space 2210 * @size: size of the area 2211 * @ptes: returns the PTEs for the address space 2212 * 2213 * Returns: NULL on failure, vm_struct on success 2214 * 2215 * This function reserves a range of kernel address space, and 2216 * allocates pagetables to map that range. No actual mappings 2217 * are created. 2218 * 2219 * If @ptes is non-NULL, pointers to the PTEs (in init_mm) 2220 * allocated for the VM area are returned. 2221 */ 2222 struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes) 2223 { 2224 struct vm_struct *area; 2225 2226 area = get_vm_area_caller(size, VM_IOREMAP, 2227 __builtin_return_address(0)); 2228 if (area == NULL) 2229 return NULL; 2230 2231 /* 2232 * This ensures that page tables are constructed for this region 2233 * of kernel virtual address space and mapped into init_mm. 2234 */ 2235 if (apply_to_page_range(&init_mm, (unsigned long)area->addr, 2236 size, f, ptes ? &ptes : NULL)) { 2237 free_vm_area(area); 2238 return NULL; 2239 } 2240 2241 return area; 2242 } 2243 EXPORT_SYMBOL_GPL(alloc_vm_area); 2244 2245 void free_vm_area(struct vm_struct *area) 2246 { 2247 struct vm_struct *ret; 2248 ret = remove_vm_area(area->addr); 2249 BUG_ON(ret != area); 2250 kfree(area); 2251 } 2252 EXPORT_SYMBOL_GPL(free_vm_area); 2253 2254 #ifdef CONFIG_SMP 2255 static struct vmap_area *node_to_va(struct rb_node *n) 2256 { 2257 return n ? rb_entry(n, struct vmap_area, rb_node) : NULL; 2258 } 2259 2260 /** 2261 * pvm_find_next_prev - find the next and prev vmap_area surrounding @end 2262 * @end: target address 2263 * @pnext: out arg for the next vmap_area 2264 * @pprev: out arg for the previous vmap_area 2265 * 2266 * Returns: %true if either or both of next and prev are found, 2267 * %false if no vmap_area exists 2268 * 2269 * Find vmap_areas end addresses of which enclose @end. ie. if not 2270 * NULL, *pnext->va_end > @end and *pprev->va_end <= @end. 2271 */ 2272 static bool pvm_find_next_prev(unsigned long end, 2273 struct vmap_area **pnext, 2274 struct vmap_area **pprev) 2275 { 2276 struct rb_node *n = vmap_area_root.rb_node; 2277 struct vmap_area *va = NULL; 2278 2279 while (n) { 2280 va = rb_entry(n, struct vmap_area, rb_node); 2281 if (end < va->va_end) 2282 n = n->rb_left; 2283 else if (end > va->va_end) 2284 n = n->rb_right; 2285 else 2286 break; 2287 } 2288 2289 if (!va) 2290 return false; 2291 2292 if (va->va_end > end) { 2293 *pnext = va; 2294 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node)); 2295 } else { 2296 *pprev = va; 2297 *pnext = node_to_va(rb_next(&(*pprev)->rb_node)); 2298 } 2299 return true; 2300 } 2301 2302 /** 2303 * pvm_determine_end - find the highest aligned address between two vmap_areas 2304 * @pnext: in/out arg for the next vmap_area 2305 * @pprev: in/out arg for the previous vmap_area 2306 * @align: alignment 2307 * 2308 * Returns: determined end address 2309 * 2310 * Find the highest aligned address between *@pnext and *@pprev below 2311 * VMALLOC_END. *@pnext and *@pprev are adjusted so that the aligned 2312 * down address is between the end addresses of the two vmap_areas. 2313 * 2314 * Please note that the address returned by this function may fall 2315 * inside *@pnext vmap_area. The caller is responsible for checking 2316 * that. 2317 */ 2318 static unsigned long pvm_determine_end(struct vmap_area **pnext, 2319 struct vmap_area **pprev, 2320 unsigned long align) 2321 { 2322 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1); 2323 unsigned long addr; 2324 2325 if (*pnext) 2326 addr = min((*pnext)->va_start & ~(align - 1), vmalloc_end); 2327 else 2328 addr = vmalloc_end; 2329 2330 while (*pprev && (*pprev)->va_end > addr) { 2331 *pnext = *pprev; 2332 *pprev = node_to_va(rb_prev(&(*pnext)->rb_node)); 2333 } 2334 2335 return addr; 2336 } 2337 2338 /** 2339 * pcpu_get_vm_areas - allocate vmalloc areas for percpu allocator 2340 * @offsets: array containing offset of each area 2341 * @sizes: array containing size of each area 2342 * @nr_vms: the number of areas to allocate 2343 * @align: alignment, all entries in @offsets and @sizes must be aligned to this 2344 * 2345 * Returns: kmalloc'd vm_struct pointer array pointing to allocated 2346 * vm_structs on success, %NULL on failure 2347 * 2348 * Percpu allocator wants to use congruent vm areas so that it can 2349 * maintain the offsets among percpu areas. This function allocates 2350 * congruent vmalloc areas for it with GFP_KERNEL. These areas tend to 2351 * be scattered pretty far, distance between two areas easily going up 2352 * to gigabytes. To avoid interacting with regular vmallocs, these 2353 * areas are allocated from top. 2354 * 2355 * Despite its complicated look, this allocator is rather simple. It 2356 * does everything top-down and scans areas from the end looking for 2357 * matching slot. While scanning, if any of the areas overlaps with 2358 * existing vmap_area, the base address is pulled down to fit the 2359 * area. Scanning is repeated till all the areas fit and then all 2360 * necessary data structres are inserted and the result is returned. 2361 */ 2362 struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, 2363 const size_t *sizes, int nr_vms, 2364 size_t align) 2365 { 2366 const unsigned long vmalloc_start = ALIGN(VMALLOC_START, align); 2367 const unsigned long vmalloc_end = VMALLOC_END & ~(align - 1); 2368 struct vmap_area **vas, *prev, *next; 2369 struct vm_struct **vms; 2370 int area, area2, last_area, term_area; 2371 unsigned long base, start, end, last_end; 2372 bool purged = false; 2373 2374 /* verify parameters and allocate data structures */ 2375 BUG_ON(align & ~PAGE_MASK || !is_power_of_2(align)); 2376 for (last_area = 0, area = 0; area < nr_vms; area++) { 2377 start = offsets[area]; 2378 end = start + sizes[area]; 2379 2380 /* is everything aligned properly? */ 2381 BUG_ON(!IS_ALIGNED(offsets[area], align)); 2382 BUG_ON(!IS_ALIGNED(sizes[area], align)); 2383 2384 /* detect the area with the highest address */ 2385 if (start > offsets[last_area]) 2386 last_area = area; 2387 2388 for (area2 = 0; area2 < nr_vms; area2++) { 2389 unsigned long start2 = offsets[area2]; 2390 unsigned long end2 = start2 + sizes[area2]; 2391 2392 if (area2 == area) 2393 continue; 2394 2395 BUG_ON(start2 >= start && start2 < end); 2396 BUG_ON(end2 <= end && end2 > start); 2397 } 2398 } 2399 last_end = offsets[last_area] + sizes[last_area]; 2400 2401 if (vmalloc_end - vmalloc_start < last_end) { 2402 WARN_ON(true); 2403 return NULL; 2404 } 2405 2406 vms = kcalloc(nr_vms, sizeof(vms[0]), GFP_KERNEL); 2407 vas = kcalloc(nr_vms, sizeof(vas[0]), GFP_KERNEL); 2408 if (!vas || !vms) 2409 goto err_free2; 2410 2411 for (area = 0; area < nr_vms; area++) { 2412 vas[area] = kzalloc(sizeof(struct vmap_area), GFP_KERNEL); 2413 vms[area] = kzalloc(sizeof(struct vm_struct), GFP_KERNEL); 2414 if (!vas[area] || !vms[area]) 2415 goto err_free; 2416 } 2417 retry: 2418 spin_lock(&vmap_area_lock); 2419 2420 /* start scanning - we scan from the top, begin with the last area */ 2421 area = term_area = last_area; 2422 start = offsets[area]; 2423 end = start + sizes[area]; 2424 2425 if (!pvm_find_next_prev(vmap_area_pcpu_hole, &next, &prev)) { 2426 base = vmalloc_end - last_end; 2427 goto found; 2428 } 2429 base = pvm_determine_end(&next, &prev, align) - end; 2430 2431 while (true) { 2432 BUG_ON(next && next->va_end <= base + end); 2433 BUG_ON(prev && prev->va_end > base + end); 2434 2435 /* 2436 * base might have underflowed, add last_end before 2437 * comparing. 2438 */ 2439 if (base + last_end < vmalloc_start + last_end) { 2440 spin_unlock(&vmap_area_lock); 2441 if (!purged) { 2442 purge_vmap_area_lazy(); 2443 purged = true; 2444 goto retry; 2445 } 2446 goto err_free; 2447 } 2448 2449 /* 2450 * If next overlaps, move base downwards so that it's 2451 * right below next and then recheck. 2452 */ 2453 if (next && next->va_start < base + end) { 2454 base = pvm_determine_end(&next, &prev, align) - end; 2455 term_area = area; 2456 continue; 2457 } 2458 2459 /* 2460 * If prev overlaps, shift down next and prev and move 2461 * base so that it's right below new next and then 2462 * recheck. 2463 */ 2464 if (prev && prev->va_end > base + start) { 2465 next = prev; 2466 prev = node_to_va(rb_prev(&next->rb_node)); 2467 base = pvm_determine_end(&next, &prev, align) - end; 2468 term_area = area; 2469 continue; 2470 } 2471 2472 /* 2473 * This area fits, move on to the previous one. If 2474 * the previous one is the terminal one, we're done. 2475 */ 2476 area = (area + nr_vms - 1) % nr_vms; 2477 if (area == term_area) 2478 break; 2479 start = offsets[area]; 2480 end = start + sizes[area]; 2481 pvm_find_next_prev(base + end, &next, &prev); 2482 } 2483 found: 2484 /* we've found a fitting base, insert all va's */ 2485 for (area = 0; area < nr_vms; area++) { 2486 struct vmap_area *va = vas[area]; 2487 2488 va->va_start = base + offsets[area]; 2489 va->va_end = va->va_start + sizes[area]; 2490 __insert_vmap_area(va); 2491 } 2492 2493 vmap_area_pcpu_hole = base + offsets[last_area]; 2494 2495 spin_unlock(&vmap_area_lock); 2496 2497 /* insert all vm's */ 2498 for (area = 0; area < nr_vms; area++) 2499 setup_vmalloc_vm(vms[area], vas[area], VM_ALLOC, 2500 pcpu_get_vm_areas); 2501 2502 kfree(vas); 2503 return vms; 2504 2505 err_free: 2506 for (area = 0; area < nr_vms; area++) { 2507 kfree(vas[area]); 2508 kfree(vms[area]); 2509 } 2510 err_free2: 2511 kfree(vas); 2512 kfree(vms); 2513 return NULL; 2514 } 2515 2516 /** 2517 * pcpu_free_vm_areas - free vmalloc areas for percpu allocator 2518 * @vms: vm_struct pointer array returned by pcpu_get_vm_areas() 2519 * @nr_vms: the number of allocated areas 2520 * 2521 * Free vm_structs and the array allocated by pcpu_get_vm_areas(). 2522 */ 2523 void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) 2524 { 2525 int i; 2526 2527 for (i = 0; i < nr_vms; i++) 2528 free_vm_area(vms[i]); 2529 kfree(vms); 2530 } 2531 #endif /* CONFIG_SMP */ 2532 2533 #ifdef CONFIG_PROC_FS 2534 static void *s_start(struct seq_file *m, loff_t *pos) 2535 __acquires(&vmap_area_lock) 2536 { 2537 loff_t n = *pos; 2538 struct vmap_area *va; 2539 2540 spin_lock(&vmap_area_lock); 2541 va = list_entry((&vmap_area_list)->next, typeof(*va), list); 2542 while (n > 0 && &va->list != &vmap_area_list) { 2543 n--; 2544 va = list_entry(va->list.next, typeof(*va), list); 2545 } 2546 if (!n && &va->list != &vmap_area_list) 2547 return va; 2548 2549 return NULL; 2550 2551 } 2552 2553 static void *s_next(struct seq_file *m, void *p, loff_t *pos) 2554 { 2555 struct vmap_area *va = p, *next; 2556 2557 ++*pos; 2558 next = list_entry(va->list.next, typeof(*va), list); 2559 if (&next->list != &vmap_area_list) 2560 return next; 2561 2562 return NULL; 2563 } 2564 2565 static void s_stop(struct seq_file *m, void *p) 2566 __releases(&vmap_area_lock) 2567 { 2568 spin_unlock(&vmap_area_lock); 2569 } 2570 2571 static void show_numa_info(struct seq_file *m, struct vm_struct *v) 2572 { 2573 if (IS_ENABLED(CONFIG_NUMA)) { 2574 unsigned int nr, *counters = m->private; 2575 2576 if (!counters) 2577 return; 2578 2579 /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ 2580 smp_rmb(); 2581 if (v->flags & VM_UNINITIALIZED) 2582 return; 2583 2584 memset(counters, 0, nr_node_ids * sizeof(unsigned int)); 2585 2586 for (nr = 0; nr < v->nr_pages; nr++) 2587 counters[page_to_nid(v->pages[nr])]++; 2588 2589 for_each_node_state(nr, N_HIGH_MEMORY) 2590 if (counters[nr]) 2591 seq_printf(m, " N%u=%u", nr, counters[nr]); 2592 } 2593 } 2594 2595 static int s_show(struct seq_file *m, void *p) 2596 { 2597 struct vmap_area *va = p; 2598 struct vm_struct *v; 2599 2600 /* 2601 * s_show can encounter race with remove_vm_area, !VM_VM_AREA on 2602 * behalf of vmap area is being tear down or vm_map_ram allocation. 2603 */ 2604 if (!(va->flags & VM_VM_AREA)) 2605 return 0; 2606 2607 v = va->vm; 2608 2609 seq_printf(m, "0x%pK-0x%pK %7ld", 2610 v->addr, v->addr + v->size, v->size); 2611 2612 if (v->caller) 2613 seq_printf(m, " %pS", v->caller); 2614 2615 if (v->nr_pages) 2616 seq_printf(m, " pages=%d", v->nr_pages); 2617 2618 if (v->phys_addr) 2619 seq_printf(m, " phys=%llx", (unsigned long long)v->phys_addr); 2620 2621 if (v->flags & VM_IOREMAP) 2622 seq_printf(m, " ioremap"); 2623 2624 if (v->flags & VM_ALLOC) 2625 seq_printf(m, " vmalloc"); 2626 2627 if (v->flags & VM_MAP) 2628 seq_printf(m, " vmap"); 2629 2630 if (v->flags & VM_USERMAP) 2631 seq_printf(m, " user"); 2632 2633 if (v->flags & VM_VPAGES) 2634 seq_printf(m, " vpages"); 2635 2636 show_numa_info(m, v); 2637 seq_putc(m, '\n'); 2638 return 0; 2639 } 2640 2641 static const struct seq_operations vmalloc_op = { 2642 .start = s_start, 2643 .next = s_next, 2644 .stop = s_stop, 2645 .show = s_show, 2646 }; 2647 2648 static int vmalloc_open(struct inode *inode, struct file *file) 2649 { 2650 unsigned int *ptr = NULL; 2651 int ret; 2652 2653 if (IS_ENABLED(CONFIG_NUMA)) { 2654 ptr = kmalloc(nr_node_ids * sizeof(unsigned int), GFP_KERNEL); 2655 if (ptr == NULL) 2656 return -ENOMEM; 2657 } 2658 ret = seq_open(file, &vmalloc_op); 2659 if (!ret) { 2660 struct seq_file *m = file->private_data; 2661 m->private = ptr; 2662 } else 2663 kfree(ptr); 2664 return ret; 2665 } 2666 2667 static const struct file_operations proc_vmalloc_operations = { 2668 .open = vmalloc_open, 2669 .read = seq_read, 2670 .llseek = seq_lseek, 2671 .release = seq_release_private, 2672 }; 2673 2674 static int __init proc_vmalloc_init(void) 2675 { 2676 proc_create("vmallocinfo", S_IRUSR, NULL, &proc_vmalloc_operations); 2677 return 0; 2678 } 2679 module_init(proc_vmalloc_init); 2680 2681 void get_vmalloc_info(struct vmalloc_info *vmi) 2682 { 2683 struct vmap_area *va; 2684 unsigned long free_area_size; 2685 unsigned long prev_end; 2686 2687 vmi->used = 0; 2688 vmi->largest_chunk = 0; 2689 2690 prev_end = VMALLOC_START; 2691 2692 spin_lock(&vmap_area_lock); 2693 2694 if (list_empty(&vmap_area_list)) { 2695 vmi->largest_chunk = VMALLOC_TOTAL; 2696 goto out; 2697 } 2698 2699 list_for_each_entry(va, &vmap_area_list, list) { 2700 unsigned long addr = va->va_start; 2701 2702 /* 2703 * Some archs keep another range for modules in vmalloc space 2704 */ 2705 if (addr < VMALLOC_START) 2706 continue; 2707 if (addr >= VMALLOC_END) 2708 break; 2709 2710 if (va->flags & (VM_LAZY_FREE | VM_LAZY_FREEING)) 2711 continue; 2712 2713 vmi->used += (va->va_end - va->va_start); 2714 2715 free_area_size = addr - prev_end; 2716 if (vmi->largest_chunk < free_area_size) 2717 vmi->largest_chunk = free_area_size; 2718 2719 prev_end = va->va_end; 2720 } 2721 2722 if (VMALLOC_END - prev_end > vmi->largest_chunk) 2723 vmi->largest_chunk = VMALLOC_END - prev_end; 2724 2725 out: 2726 spin_unlock(&vmap_area_lock); 2727 } 2728 #endif 2729 2730