arch/x86/mm/pageattr.c

   1 /*
   2  * Copyright 2002 Andi Kleen, SuSE Labs.
   3  * Thanks to Ben LaHaise for precious feedback.
   4  */
   5 #include <linux/highmem.h>
   6 #include <linux/bootmem.h>
   7 #include <linux/module.h>
   8 #include <linux/sched.h>
   9 #include <linux/slab.h>
  10 #include <linux/mm.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/debugfs.h>
  14
  15 #include <asm/e820.h>
  16 #include <asm/processor.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/sections.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/pgalloc.h>
  21 #include <asm/proto.h>
  22 #include <asm/pat.h>
  23
  24 /*
  25  * The current flushing context - we pass it instead of 5 arguments:
  26  */
  27 struct cpa_data {
  28         unsigned long   vaddr;
  29         pgprot_t        mask_set;
  30         pgprot_t        mask_clr;
  31         int             numpages;
  32         int             flushtlb;
  33         unsigned long   pfn;
  34         unsigned        force_split : 1;
  35 };
  36
  37 #ifdef CONFIG_PROC_FS
  38 static unsigned long direct_pages_count[PG_LEVEL_NUM];
  39
  40 void update_page_count(int level, unsigned long pages)
  41 {
  42         unsigned long flags;
  43
  44         /* Protect against CPA */
  45         spin_lock_irqsave(&pgd_lock, flags);
  46         direct_pages_count[level] += pages;
  47         spin_unlock_irqrestore(&pgd_lock, flags);
  48 }
  49
  50 static void split_page_count(int level)
  51 {
  52         direct_pages_count[level]--;
  53         direct_pages_count[level - 1] += PTRS_PER_PTE;
  54 }
  55
  56 int arch_report_meminfo(char *page)
  57 {
  58         int n = sprintf(page, "DirectMap4k:  %8lu\n"
  59                         "DirectMap2M:  %8lu\n",
  60                         direct_pages_count[PG_LEVEL_4K],
  61                         direct_pages_count[PG_LEVEL_2M]);
  62 #ifdef CONFIG_X86_64
  63         n += sprintf(page + n, "DirectMap1G:  %8lu\n",
  64                      direct_pages_count[PG_LEVEL_1G]);
  65 #endif
  66         return n;
  67 }
  68 #else
  69 static inline void split_page_count(int level) { }
  70 #endif
  71
  72 #ifdef CONFIG_X86_64
  73
  74 static inline unsigned long highmap_start_pfn(void)
  75 {
  76         return __pa(_text) >> PAGE_SHIFT;
  77 }
  78
  79 static inline unsigned long highmap_end_pfn(void)
  80 {
  81         return __pa(round_up((unsigned long)_end, PMD_SIZE)) >> PAGE_SHIFT;
  82 }
  83
  84 #endif
  85
  86 #ifdef CONFIG_DEBUG_PAGEALLOC
  87 # define debug_pagealloc 1
  88 #else
  89 # define debug_pagealloc 0
  90 #endif
  91
  92 static inline int
  93 within(unsigned long addr, unsigned long start, unsigned long end)
  94 {
  95         return addr >= start && addr < end;
  96 }
  97
  98 /*
  99  * Flushing functions
 100  */
 101
 102 /**
 103  * clflush_cache_range - flush a cache range with clflush
 104  * @addr:       virtual start address
 105  * @size:       number of bytes to flush
 106  *
 107  * clflush is an unordered instruction which needs fencing with mfence
 108  * to avoid ordering issues.
 109  */
 110 void clflush_cache_range(void *vaddr, unsigned int size)
 111 {
 112         void *vend = vaddr + size - 1;
 113
 114         mb();
 115
 116         for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size)
 117                 clflush(vaddr);
 118         /*
 119          * Flush any possible final partial cacheline:
 120          */
 121         clflush(vend);
 122
 123         mb();
 124 }
 125
 126 static void __cpa_flush_all(void *arg)
 127 {
 128         unsigned long cache = (unsigned long)arg;
 129
 130         /*
 131          * Flush all to work around Errata in early athlons regarding
 132          * large page flushing.
 133          */
 134         __flush_tlb_all();
 135
 136         if (cache && boot_cpu_data.x86_model >= 4)
 137                 wbinvd();
 138 }
 139
 140 static void cpa_flush_all(unsigned long cache)
 141 {
 142         BUG_ON(irqs_disabled());
 143
 144         on_each_cpu(__cpa_flush_all, (void *) cache, 1);
 145 }
 146
 147 static void __cpa_flush_range(void *arg)
 148 {
 149         /*
 150          * We could optimize that further and do individual per page
 151          * tlb invalidates for a low number of pages. Caveat: we must
 152          * flush the high aliases on 64bit as well.
 153          */
 154         __flush_tlb_all();
 155 }
 156
 157 static void cpa_flush_range(unsigned long start, int numpages, int cache)
 158 {
 159         unsigned int i, level;
 160         unsigned long addr;
 161
 162         BUG_ON(irqs_disabled());
 163         WARN_ON(PAGE_ALIGN(start) != start);
 164
 165         on_each_cpu(__cpa_flush_range, NULL, 1);
 166
 167         if (!cache)
 168                 return;
 169
 170         /*
 171          * We only need to flush on one CPU,
 172          * clflush is a MESI-coherent instruction that
 173          * will cause all other CPUs to flush the same
 174          * cachelines:
 175          */
 176         for (i = 0, addr = start; i < numpages; i++, addr += PAGE_SIZE) {
 177                 pte_t *pte = lookup_address(addr, &level);
 178
 179                 /*
 180                  * Only flush present addresses:
 181                  */
 182                 if (pte && (pte_val(*pte) & _PAGE_PRESENT))
 183                         clflush_cache_range((void *) addr, PAGE_SIZE);
 184         }
 185 }
 186
 187 /*
 188  * Certain areas of memory on x86 require very specific protection flags,
 189  * for example the BIOS area or kernel text. Callers don't always get this
 190  * right (again, ioremap() on BIOS memory is not uncommon) so this function
 191  * checks and fixes these known static required protection bits.
 192  */
 193 static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
 194                                    unsigned long pfn)
 195 {
 196         pgprot_t forbidden = __pgprot(0);
 197
 198         /*
 199          * The BIOS area between 640k and 1Mb needs to be executable for
 200          * PCI BIOS based config access (CONFIG_PCI_GOBIOS) support.
 201          */
 202         if (within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT))
 203                 pgprot_val(forbidden) |= _PAGE_NX;
 204
 205         /*
 206          * The kernel text needs to be executable for obvious reasons
 207          * Does not cover __inittext since that is gone later on. On
 208          * 64bit we do not enforce !NX on the low mapping
 209          */
 210         if (within(address, (unsigned long)_text, (unsigned long)_etext))
 211                 pgprot_val(forbidden) |= _PAGE_NX;
 212
 213         /*
 214          * The .rodata section needs to be read-only. Using the pfn
 215          * catches all aliases.
 216          */
 217         if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT,
 218                    __pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
 219                 pgprot_val(forbidden) |= _PAGE_RW;
 220
 221         prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
 222
 223         return prot;
 224 }
 225
 226 /*
 227  * Lookup the page table entry for a virtual address. Return a pointer
 228  * to the entry and the level of the mapping.
 229  *
 230  * Note: We return pud and pmd either when the entry is marked large
 231  * or when the present bit is not set. Otherwise we would return a
 232  * pointer to a nonexisting mapping.
 233  */
 234 pte_t *lookup_address(unsigned long address, unsigned int *level)
 235 {
 236         pgd_t *pgd = pgd_offset_k(address);
 237         pud_t *pud;
 238         pmd_t *pmd;
 239
 240         *level = PG_LEVEL_NONE;
 241
 242         if (pgd_none(*pgd))
 243                 return NULL;
 244
 245         pud = pud_offset(pgd, address);
 246         if (pud_none(*pud))
 247                 return NULL;
 248
 249         *level = PG_LEVEL_1G;
 250         if (pud_large(*pud) || !pud_present(*pud))
 251                 return (pte_t *)pud;
 252
 253         pmd = pmd_offset(pud, address);
 254         if (pmd_none(*pmd))
 255                 return NULL;
 256
 257         *level = PG_LEVEL_2M;
 258         if (pmd_large(*pmd) || !pmd_present(*pmd))
 259                 return (pte_t *)pmd;
 260
 261         *level = PG_LEVEL_4K;
 262
 263         return pte_offset_kernel(pmd, address);
 264 }
 265 EXPORT_SYMBOL_GPL(lookup_address);
 266
 267 /*
 268  * Set the new pmd in all the pgds we know about:
 269  */
 270 static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
 271 {
 272         /* change init_mm */
 273         set_pte_atomic(kpte, pte);
 274 #ifdef CONFIG_X86_32
 275         if (!SHARED_KERNEL_PMD) {
 276                 struct page *page;
 277
 278                 list_for_each_entry(page, &pgd_list, lru) {
 279                         pgd_t *pgd;
 280                         pud_t *pud;
 281                         pmd_t *pmd;
 282
 283                         pgd = (pgd_t *)page_address(page) + pgd_index(address);
 284                         pud = pud_offset(pgd, address);
 285                         pmd = pmd_offset(pud, address);
 286                         set_pte_atomic((pte_t *)pmd, pte);
 287                 }
 288         }
 289 #endif
 290 }
 291
 292 static int
 293 try_preserve_large_page(pte_t *kpte, unsigned long address,
 294                         struct cpa_data *cpa)
 295 {
 296         unsigned long nextpage_addr, numpages, pmask, psize, flags, addr, pfn;
 297         pte_t new_pte, old_pte, *tmp;
 298         pgprot_t old_prot, new_prot;
 299         int i, do_split = 1;
 300         unsigned int level;
 301
 302         if (cpa->force_split)
 303                 return 1;
 304
 305         spin_lock_irqsave(&pgd_lock, flags);
 306         /*
 307          * Check for races, another CPU might have split this page
 308          * up already:
 309          */
 310         tmp = lookup_address(address, &level);
 311         if (tmp != kpte)
 312                 goto out_unlock;
 313
 314         switch (level) {
 315         case PG_LEVEL_2M:
 316                 psize = PMD_PAGE_SIZE;
 317                 pmask = PMD_PAGE_MASK;
 318                 break;
 319 #ifdef CONFIG_X86_64
 320         case PG_LEVEL_1G:
 321                 psize = PUD_PAGE_SIZE;
 322                 pmask = PUD_PAGE_MASK;
 323                 break;
 324 #endif
 325         default:
 326                 do_split = -EINVAL;
 327                 goto out_unlock;
 328         }
 329
 330         /*
 331          * Calculate the number of pages, which fit into this large
 332          * page starting at address:
 333          */
 334         nextpage_addr = (address + psize) & pmask;
 335         numpages = (nextpage_addr - address) >> PAGE_SHIFT;
 336         if (numpages < cpa->numpages)
 337                 cpa->numpages = numpages;
 338
 339         /*
 340          * We are safe now. Check whether the new pgprot is the same:
 341          */
 342         old_pte = *kpte;
 343         old_prot = new_prot = pte_pgprot(old_pte);
 344
 345         pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);
 346         pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
 347
 348         /*
 349          * old_pte points to the large page base address. So we need
 350          * to add the offset of the virtual address:
 351          */
 352         pfn = pte_pfn(old_pte) + ((address & (psize - 1)) >> PAGE_SHIFT);
 353         cpa->pfn = pfn;
 354
 355         new_prot = static_protections(new_prot, address, pfn);
 356
 357         /*
 358          * We need to check the full range, whether
 359          * static_protection() requires a different pgprot for one of
 360          * the pages in the range we try to preserve:
 361          */
 362         addr = address + PAGE_SIZE;
 363         pfn++;
 364         for (i = 1; i < cpa->numpages; i++, addr += PAGE_SIZE, pfn++) {
 365                 pgprot_t chk_prot = static_protections(new_prot, addr, pfn);
 366
 367                 if (pgprot_val(chk_prot) != pgprot_val(new_prot))
 368                         goto out_unlock;
 369         }
 370
 371         /*
 372          * If there are no changes, return. maxpages has been updated
 373          * above:
 374          */
 375         if (pgprot_val(new_prot) == pgprot_val(old_prot)) {
 376                 do_split = 0;
 377                 goto out_unlock;
 378         }
 379
 380         /*
 381          * We need to change the attributes. Check, whether we can
 382          * change the large page in one go. We request a split, when
 383          * the address is not aligned and the number of pages is
 384          * smaller than the number of pages in the large page. Note
 385          * that we limited the number of possible pages already to
 386          * the number of pages in the large page.
 387          */
 388         if (address == (nextpage_addr - psize) && cpa->numpages == numpages) {
 389                 /*
 390                  * The address is aligned and the number of pages
 391                  * covers the full page.
 392                  */
 393                 new_pte = pfn_pte(pte_pfn(old_pte), canon_pgprot(new_prot));
 394                 __set_pmd_pte(kpte, address, new_pte);
 395                 cpa->flushtlb = 1;
 396                 do_split = 0;
 397         }
 398
 399 out_unlock:
 400         spin_unlock_irqrestore(&pgd_lock, flags);
 401
 402         return do_split;
 403 }
 404
 405 static LIST_HEAD(page_pool);
 406 static unsigned long pool_size, pool_pages, pool_low;
 407 static unsigned long pool_used, pool_failed;
 408
 409 static void cpa_fill_pool(struct page **ret)
 410 {
 411         gfp_t gfp = GFP_KERNEL;
 412         unsigned long flags;
 413         struct page *p;
 414
 415         /*
 416          * Avoid recursion (on debug-pagealloc) and also signal
 417          * our priority to get to these pagetables:
 418          */
 419         if (current->flags & PF_MEMALLOC)
 420                 return;
 421         current->flags |= PF_MEMALLOC;
 422
 423         /*
 424          * Allocate atomically from atomic contexts:
 425          */
 426         if (in_atomic() || irqs_disabled() || debug_pagealloc)
 427                 gfp =  GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
 428
 429         while (pool_pages < pool_size || (ret && !*ret)) {
 430                 p = alloc_pages(gfp, 0);
 431                 if (!p) {
 432                         pool_failed++;
 433                         break;
 434                 }
 435                 /*
 436                  * If the call site needs a page right now, provide it:
 437                  */
 438                 if (ret && !*ret) {
 439                         *ret = p;
 440                         continue;
 441                 }
 442                 spin_lock_irqsave(&pgd_lock, flags);
 443                 list_add(&p->lru, &page_pool);
 444                 pool_pages++;
 445                 spin_unlock_irqrestore(&pgd_lock, flags);
 446         }
 447
 448         current->flags &= ~PF_MEMALLOC;
 449 }
 450
 451 #define SHIFT_MB                (20 - PAGE_SHIFT)
 452 #define ROUND_MB_GB             ((1 << 10) - 1)
 453 #define SHIFT_MB_GB             10
 454 #define POOL_PAGES_PER_GB       16
 455
 456 void __init cpa_init(void)
 457 {
 458         struct sysinfo si;
 459         unsigned long gb;
 460
 461         si_meminfo(&si);
 462         /*
 463          * Calculate the number of pool pages:
 464          *
 465          * Convert totalram (nr of pages) to MiB and round to the next
 466          * GiB. Shift MiB to Gib and multiply the result by
 467          * POOL_PAGES_PER_GB:
 468          */
 469         if (debug_pagealloc) {
 470                 gb = ((si.totalram >> SHIFT_MB) + ROUND_MB_GB) >> SHIFT_MB_GB;
 471                 pool_size = POOL_PAGES_PER_GB * gb;
 472         } else {
 473                 pool_size = 1;
 474         }
 475         pool_low = pool_size;
 476
 477         cpa_fill_pool(NULL);
 478         printk(KERN_DEBUG
 479                "CPA: page pool initialized %lu of %lu pages preallocated\n",
 480                pool_pages, pool_size);
 481 }
 482
 483 static int split_large_page(pte_t *kpte, unsigned long address)
 484 {
 485         unsigned long flags, pfn, pfninc = 1;
 486         unsigned int i, level;
 487         pte_t *pbase, *tmp;
 488         pgprot_t ref_prot;
 489         struct page *base;
 490
 491         /*
 492          * Get a page from the pool. The pool list is protected by the
 493          * pgd_lock, which we have to take anyway for the split
 494          * operation:
 495          */
 496         spin_lock_irqsave(&pgd_lock, flags);
 497         if (list_empty(&page_pool)) {
 498                 spin_unlock_irqrestore(&pgd_lock, flags);
 499                 base = NULL;
 500                 cpa_fill_pool(&base);
 501                 if (!base)
 502                         return -ENOMEM;
 503                 spin_lock_irqsave(&pgd_lock, flags);
 504         } else {
 505                 base = list_first_entry(&page_pool, struct page, lru);
 506                 list_del(&base->lru);
 507                 pool_pages--;
 508
 509                 if (pool_pages < pool_low)
 510                         pool_low = pool_pages;
 511         }
 512
 513         /*
 514          * Check for races, another CPU might have split this page
 515          * up for us already:
 516          */
 517         tmp = lookup_address(address, &level);
 518         if (tmp != kpte)
 519                 goto out_unlock;
 520
 521         pbase = (pte_t *)page_address(base);
 522         paravirt_alloc_pte(&init_mm, page_to_pfn(base));
 523         ref_prot = pte_pgprot(pte_clrhuge(*kpte));
 524
 525 #ifdef CONFIG_X86_64
 526         if (level == PG_LEVEL_1G) {
 527                 pfninc = PMD_PAGE_SIZE >> PAGE_SHIFT;
 528                 pgprot_val(ref_prot) |= _PAGE_PSE;
 529         }
 530 #endif
 531
 532         /*
 533          * Get the target pfn from the original entry:
 534          */
 535         pfn = pte_pfn(*kpte);
 536         for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc)
 537                 set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
 538
 539         if (address >= (unsigned long)__va(0) &&
 540                 address < (unsigned long)__va(max_low_pfn_mapped << PAGE_SHIFT))
 541                 split_page_count(level);
 542
 543 #ifdef CONFIG_X86_64
 544         if (address >= (unsigned long)__va(1UL<<32) &&
 545                 address < (unsigned long)__va(max_pfn_mapped << PAGE_SHIFT))
 546                 split_page_count(level);
 547 #endif
 548
 549         /*
 550          * Install the new, split up pagetable. Important details here:
 551          *
 552          * On Intel the NX bit of all levels must be cleared to make a
 553          * page executable. See section 4.13.2 of Intel 64 and IA-32
 554          * Architectures Software Developer's Manual).
 555          *
 556          * Mark the entry present. The current mapping might be
 557          * set to not present, which we preserved above.
 558          */
 559         ref_prot = pte_pgprot(pte_mkexec(pte_clrhuge(*kpte)));
 560         pgprot_val(ref_prot) |= _PAGE_PRESENT;
 561         __set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
 562         base = NULL;
 563
 564 out_unlock:
 565         /*
 566          * If we dropped out via the lookup_address check under
 567          * pgd_lock then stick the page back into the pool:
 568          */
 569         if (base) {
 570                 list_add(&base->lru, &page_pool);
 571                 pool_pages++;
 572         } else
 573                 pool_used++;
 574         spin_unlock_irqrestore(&pgd_lock, flags);
 575
 576         return 0;
 577 }
 578
 579 static int __change_page_attr(struct cpa_data *cpa, int primary)
 580 {
 581         unsigned long address = cpa->vaddr;
 582         int do_split, err;
 583         unsigned int level;
 584         pte_t *kpte, old_pte;
 585
 586 repeat:
 587         kpte = lookup_address(address, &level);
 588         if (!kpte)
 589                 return 0;
 590
 591         old_pte = *kpte;
 592         if (!pte_val(old_pte)) {
 593                 if (!primary)
 594                         return 0;
 595                 printk(KERN_WARNING "CPA: called for zero pte. "
 596                        "vaddr = %lx cpa->vaddr = %lx\n", address,
 597                        cpa->vaddr);
 598                 WARN_ON(1);
 599                 return -EINVAL;
 600         }
 601
 602         if (level == PG_LEVEL_4K) {
 603                 pte_t new_pte;
 604                 pgprot_t new_prot = pte_pgprot(old_pte);
 605                 unsigned long pfn = pte_pfn(old_pte);
 606
 607                 pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);
 608                 pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
 609
 610                 new_prot = static_protections(new_prot, address, pfn);
 611
 612                 /*
 613                  * We need to keep the pfn from the existing PTE,
 614                  * after all we're only going to change it's attributes
 615                  * not the memory it points to
 616                  */
 617                 new_pte = pfn_pte(pfn, canon_pgprot(new_prot));
 618                 cpa->pfn = pfn;
 619                 /*
 620                  * Do we really change anything ?
 621                  */
 622                 if (pte_val(old_pte) != pte_val(new_pte)) {
 623                         set_pte_atomic(kpte, new_pte);
 624                         cpa->flushtlb = 1;
 625                 }
 626                 cpa->numpages = 1;
 627                 return 0;
 628         }
 629
 630         /*
 631          * Check, whether we can keep the large page intact
 632          * and just change the pte:
 633          */
 634         do_split = try_preserve_large_page(kpte, address, cpa);
 635         /*
 636          * When the range fits into the existing large page,
 637          * return. cp->numpages and cpa->tlbflush have been updated in
 638          * try_large_page:
 639          */
 640         if (do_split <= 0)
 641                 return do_split;
 642
 643         /*
 644          * We have to split the large page:
 645          */
 646         err = split_large_page(kpte, address);
 647         if (!err) {
 648                 cpa->flushtlb = 1;
 649                 goto repeat;
 650         }
 651
 652         return err;
 653 }
 654
 655 static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias);
 656
 657 static int cpa_process_alias(struct cpa_data *cpa)
 658 {
 659         struct cpa_data alias_cpa;
 660         int ret = 0;
 661
 662         if (cpa->pfn >= max_pfn_mapped)
 663                 return 0;
 664
 665 #ifdef CONFIG_X86_64
 666         if (cpa->pfn >= max_low_pfn_mapped && cpa->pfn < (1UL<<(32-PAGE_SHIFT)))
 667                 return 0;
 668 #endif
 669         /*
 670          * No need to redo, when the primary call touched the direct
 671          * mapping already:
 672          */
 673         if (!(within(cpa->vaddr, PAGE_OFFSET,
 674                     PAGE_OFFSET + (max_low_pfn_mapped << PAGE_SHIFT))
 675 #ifdef CONFIG_X86_64
 676                 || within(cpa->vaddr, PAGE_OFFSET + (1UL<<32),
 677                     PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))
 678 #endif
 679         )) {
 680
 681                 alias_cpa = *cpa;
 682                 alias_cpa.vaddr = (unsigned long) __va(cpa->pfn << PAGE_SHIFT);
 683
 684                 ret = __change_page_attr_set_clr(&alias_cpa, 0);
 685         }
 686
 687 #ifdef CONFIG_X86_64
 688         if (ret)
 689                 return ret;
 690         /*
 691          * No need to redo, when the primary call touched the high
 692          * mapping already:
 693          */
 694         if (within(cpa->vaddr, (unsigned long) _text, (unsigned long) _end))
 695                 return 0;
 696
 697         /*
 698          * If the physical address is inside the kernel map, we need
 699          * to touch the high mapped kernel as well:
 700          */
 701         if (!within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn()))
 702                 return 0;
 703
 704         alias_cpa = *cpa;
 705         alias_cpa.vaddr =
 706                 (cpa->pfn << PAGE_SHIFT) + __START_KERNEL_map - phys_base;
 707
 708         /*
 709          * The high mapping range is imprecise, so ignore the return value.
 710          */
 711         __change_page_attr_set_clr(&alias_cpa, 0);
 712 #endif
 713         return ret;
 714 }
 715
 716 static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias)
 717 {
 718         int ret, numpages = cpa->numpages;
 719
 720         while (numpages) {
 721                 /*
 722                  * Store the remaining nr of pages for the large page
 723                  * preservation check.
 724                  */
 725                 cpa->numpages = numpages;
 726
 727                 ret = __change_page_attr(cpa, checkalias);
 728                 if (ret)
 729                         return ret;
 730
 731                 if (checkalias) {
 732                         ret = cpa_process_alias(cpa);
 733                         if (ret)
 734                                 return ret;
 735                 }
 736
 737                 /*
 738                  * Adjust the number of pages with the result of the
 739                  * CPA operation. Either a large page has been
 740                  * preserved or a single page update happened.
 741                  */
 742                 BUG_ON(cpa->numpages > numpages);
 743                 numpages -= cpa->numpages;
 744                 cpa->vaddr += cpa->numpages * PAGE_SIZE;
 745         }
 746         return 0;
 747 }
 748
 749 static inline int cache_attr(pgprot_t attr)
 750 {
 751         return pgprot_val(attr) &
 752                 (_PAGE_PAT | _PAGE_PAT_LARGE | _PAGE_PWT | _PAGE_PCD);
 753 }
 754
 755 static int change_page_attr_set_clr(unsigned long addr, int numpages,
 756                                     pgprot_t mask_set, pgprot_t mask_clr,
 757                                     int force_split)
 758 {
 759         struct cpa_data cpa;
 760         int ret, cache, checkalias;
 761
 762         /*
 763          * Check, if we are requested to change a not supported
 764          * feature:
 765          */
 766         mask_set = canon_pgprot(mask_set);
 767         mask_clr = canon_pgprot(mask_clr);
 768         if (!pgprot_val(mask_set) && !pgprot_val(mask_clr) && !force_split)
 769                 return 0;
 770
 771         /* Ensure we are PAGE_SIZE aligned */
 772         if (addr & ~PAGE_MASK) {
 773                 addr &= PAGE_MASK;
 774                 /*
 775                  * People should not be passing in unaligned addresses:
 776                  */
 777                 WARN_ON_ONCE(1);
 778         }
 779
 780         cpa.vaddr = addr;
 781         cpa.numpages = numpages;
 782         cpa.mask_set = mask_set;
 783         cpa.mask_clr = mask_clr;
 784         cpa.flushtlb = 0;
 785         cpa.force_split = force_split;
 786
 787         /* No alias checking for _NX bit modifications */
 788         checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX;
 789
 790         ret = __change_page_attr_set_clr(&cpa, checkalias);
 791
 792         /*
 793          * Check whether we really changed something:
 794          */
 795         if (!cpa.flushtlb)
 796                 goto out;
 797
 798         /*
 799          * No need to flush, when we did not set any of the caching
 800          * attributes:
 801          */
 802         cache = cache_attr(mask_set);
 803
 804         /*
 805          * On success we use clflush, when the CPU supports it to
 806          * avoid the wbindv. If the CPU does not support it and in the
 807          * error case we fall back to cpa_flush_all (which uses
 808          * wbindv):
 809          */
 810         if (!ret && cpu_has_clflush)
 811                 cpa_flush_range(addr, numpages, cache);
 812         else
 813                 cpa_flush_all(cache);
 814
 815 out:
 816         cpa_fill_pool(NULL);
 817
 818         return ret;
 819 }
 820
 821 static inline int change_page_attr_set(unsigned long addr, int numpages,
 822                                        pgprot_t mask)
 823 {
 824         return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0), 0);
 825 }
 826
 827 static inline int change_page_attr_clear(unsigned long addr, int numpages,
 828                                          pgprot_t mask)
 829 {
 830         return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask, 0);
 831 }
 832
 833 int _set_memory_uc(unsigned long addr, int numpages)
 834 {
 835         /*
 836          * for now UC MINUS. see comments in ioremap_nocache()
 837          */
 838         return change_page_attr_set(addr, numpages,
 839                                     __pgprot(_PAGE_CACHE_UC_MINUS));
 840 }
 841
 842 int set_memory_uc(unsigned long addr, int numpages)
 843 {
 844         /*
 845          * for now UC MINUS. see comments in ioremap_nocache()
 846          */
 847         if (reserve_memtype(addr, addr + numpages * PAGE_SIZE,
 848                             _PAGE_CACHE_UC_MINUS, NULL))
 849                 return -EINVAL;
 850
 851         return _set_memory_uc(addr, numpages);
 852 }
 853 EXPORT_SYMBOL(set_memory_uc);
 854
 855 int _set_memory_wc(unsigned long addr, int numpages)
 856 {
 857         return change_page_attr_set(addr, numpages,
 858                                     __pgprot(_PAGE_CACHE_WC));
 859 }
 860
 861 int set_memory_wc(unsigned long addr, int numpages)
 862 {
 863         if (!pat_enabled)
 864                 return set_memory_uc(addr, numpages);
 865
 866         if (reserve_memtype(addr, addr + numpages * PAGE_SIZE,
 867                 _PAGE_CACHE_WC, NULL))
 868                 return -EINVAL;
 869
 870         return _set_memory_wc(addr, numpages);
 871 }
 872 EXPORT_SYMBOL(set_memory_wc);
 873
 874 int _set_memory_wb(unsigned long addr, int numpages)
 875 {
 876         return change_page_attr_clear(addr, numpages,
 877                                       __pgprot(_PAGE_CACHE_MASK));
 878 }
 879
 880 int set_memory_wb(unsigned long addr, int numpages)
 881 {
 882         free_memtype(addr, addr + numpages * PAGE_SIZE);
 883
 884         return _set_memory_wb(addr, numpages);
 885 }
 886 EXPORT_SYMBOL(set_memory_wb);
 887
 888 int set_memory_x(unsigned long addr, int numpages)
 889 {
 890         return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_NX));
 891 }
 892 EXPORT_SYMBOL(set_memory_x);
 893
 894 int set_memory_nx(unsigned long addr, int numpages)
 895 {
 896         return change_page_attr_set(addr, numpages, __pgprot(_PAGE_NX));
 897 }
 898 EXPORT_SYMBOL(set_memory_nx);
 899
 900 int set_memory_ro(unsigned long addr, int numpages)
 901 {
 902         return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_RW));
 903 }
 904
 905 int set_memory_rw(unsigned long addr, int numpages)
 906 {
 907         return change_page_attr_set(addr, numpages, __pgprot(_PAGE_RW));
 908 }
 909
 910 int set_memory_np(unsigned long addr, int numpages)
 911 {
 912         return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_PRESENT));
 913 }
 914
 915 int set_memory_4k(unsigned long addr, int numpages)
 916 {
 917         return change_page_attr_set_clr(addr, numpages, __pgprot(0),
 918                                         __pgprot(0), 1);
 919 }
 920
 921 int set_pages_uc(struct page *page, int numpages)
 922 {
 923         unsigned long addr = (unsigned long)page_address(page);
 924
 925         return set_memory_uc(addr, numpages);
 926 }
 927 EXPORT_SYMBOL(set_pages_uc);
 928
 929 int set_pages_wb(struct page *page, int numpages)
 930 {
 931         unsigned long addr = (unsigned long)page_address(page);
 932
 933         return set_memory_wb(addr, numpages);
 934 }
 935 EXPORT_SYMBOL(set_pages_wb);
 936
 937 int set_pages_x(struct page *page, int numpages)
 938 {
 939         unsigned long addr = (unsigned long)page_address(page);
 940
 941         return set_memory_x(addr, numpages);
 942 }
 943 EXPORT_SYMBOL(set_pages_x);
 944
 945 int set_pages_nx(struct page *page, int numpages)
 946 {
 947         unsigned long addr = (unsigned long)page_address(page);
 948
 949         return set_memory_nx(addr, numpages);
 950 }
 951 EXPORT_SYMBOL(set_pages_nx);
 952
 953 int set_pages_ro(struct page *page, int numpages)
 954 {
 955         unsigned long addr = (unsigned long)page_address(page);
 956
 957         return set_memory_ro(addr, numpages);
 958 }
 959
 960 int set_pages_rw(struct page *page, int numpages)
 961 {
 962         unsigned long addr = (unsigned long)page_address(page);
 963
 964         return set_memory_rw(addr, numpages);
 965 }
 966
 967 #ifdef CONFIG_DEBUG_PAGEALLOC
 968
 969 static int __set_pages_p(struct page *page, int numpages)
 970 {
 971         struct cpa_data cpa = { .vaddr = (unsigned long) page_address(page),
 972                                 .numpages = numpages,
 973                                 .mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),
 974                                 .mask_clr = __pgprot(0)};
 975
 976         return __change_page_attr_set_clr(&cpa, 1);
 977 }
 978
 979 static int __set_pages_np(struct page *page, int numpages)
 980 {
 981         struct cpa_data cpa = { .vaddr = (unsigned long) page_address(page),
 982                                 .numpages = numpages,
 983                                 .mask_set = __pgprot(0),
 984                                 .mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW)};
 985
 986         return __change_page_attr_set_clr(&cpa, 1);
 987 }
 988
 989 void kernel_map_pages(struct page *page, int numpages, int enable)
 990 {
 991         if (PageHighMem(page))
 992                 return;
 993         if (!enable) {
 994                 debug_check_no_locks_freed(page_address(page),
 995                                            numpages * PAGE_SIZE);
 996         }
 997
 998         /*
 999          * If page allocator is not up yet then do not call c_p_a():
1000          */
1001         if (!debug_pagealloc_enabled)
1002                 return;
1003
1004         /*
1005          * The return value is ignored as the calls cannot fail.
1006          * Large pages are kept enabled at boot time, and are
1007          * split up quickly with DEBUG_PAGEALLOC. If a splitup
1008          * fails here (due to temporary memory shortage) no damage
1009          * is done because we just keep the largepage intact up
1010          * to the next attempt when it will likely be split up:
1011          */
1012         if (enable)
1013                 __set_pages_p(page, numpages);
1014         else
1015                 __set_pages_np(page, numpages);
1016
1017         /*
1018          * We should perform an IPI and flush all tlbs,
1019          * but that can deadlock->flush only current cpu:
1020          */
1021         __flush_tlb_all();
1022
1023         /*
1024          * Try to refill the page pool here. We can do this only after
1025          * the tlb flush.
1026          */
1027         cpa_fill_pool(NULL);
1028 }
1029
1030 #ifdef CONFIG_DEBUG_FS
1031 static int dpa_show(struct seq_file *m, void *v)
1032 {
1033         seq_puts(m, "DEBUG_PAGEALLOC\n");
1034         seq_printf(m, "pool_size     : %lu\n", pool_size);
1035         seq_printf(m, "pool_pages    : %lu\n", pool_pages);
1036         seq_printf(m, "pool_low      : %lu\n", pool_low);
1037         seq_printf(m, "pool_used     : %lu\n", pool_used);
1038         seq_printf(m, "pool_failed   : %lu\n", pool_failed);
1039
1040         return 0;
1041 }
1042
1043 static int dpa_open(struct inode *inode, struct file *filp)
1044 {
1045         return single_open(filp, dpa_show, NULL);
1046 }
1047
1048 static const struct file_operations dpa_fops = {
1049         .open           = dpa_open,
1050         .read           = seq_read,
1051         .llseek         = seq_lseek,
1052         .release        = single_release,
1053 };
1054
1055 static int __init debug_pagealloc_proc_init(void)
1056 {
1057         struct dentry *de;
1058
1059         de = debugfs_create_file("debug_pagealloc", 0600, NULL, NULL,
1060                                  &dpa_fops);
1061         if (!de)
1062                 return -ENOMEM;
1063
1064         return 0;
1065 }
1066 __initcall(debug_pagealloc_proc_init);
1067 #endif
1068
1069 #ifdef CONFIG_HIBERNATION
1070
1071 bool kernel_page_present(struct page *page)
1072 {
1073         unsigned int level;
1074         pte_t *pte;
1075
1076         if (PageHighMem(page))
1077                 return false;
1078
1079         pte = lookup_address((unsigned long)page_address(page), &level);
1080         return (pte_val(*pte) & _PAGE_PRESENT);
1081 }
1082
1083 #endif /* CONFIG_HIBERNATION */
1084
1085 #endif /* CONFIG_DEBUG_PAGEALLOC */
1086
1087 /*
1088  * The testcases use internal knowledge of the implementation that shouldn't
1089  * be exposed to the rest of the kernel. Include these directly here.
1090  */
1091 #ifdef CONFIG_CPA_DEBUG
1092 #include "pageattr-test.c"
1093 #endif