arch/x86/mm/pat.c

   1 /*
   2  * Handle caching attributes in page tables (PAT)
   3  *
   4  * Authors: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   5  *          Suresh B Siddha <suresh.b.siddha@intel.com>
   6  *
   7  * Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen.
   8  */
   9
  10 #include <linux/seq_file.h>
  11 #include <linux/bootmem.h>
  12 #include <linux/debugfs.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/mm.h>
  17 #include <linux/fs.h>
  18 #include <linux/rbtree.h>
  19
  20 #include <asm/cacheflush.h>
  21 #include <asm/processor.h>
  22 #include <asm/tlbflush.h>
  23 #include <asm/x86_init.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/fcntl.h>
  26 #include <asm/e820.h>
  27 #include <asm/mtrr.h>
  28 #include <asm/page.h>
  29 #include <asm/msr.h>
  30 #include <asm/pat.h>
  31 #include <asm/io.h>
  32
  33 #include "pat_internal.h"
  34
  35 #ifdef CONFIG_X86_PAT
  36 int __read_mostly pat_enabled = 1;
  37
  38 static inline void pat_disable(const char *reason)
  39 {
  40         pat_enabled = 0;
  41         printk(KERN_INFO "%s\n", reason);
  42 }
  43
  44 static int __init nopat(char *str)
  45 {
  46         pat_disable("PAT support disabled.");
  47         return 0;
  48 }
  49 early_param("nopat", nopat);
  50 #else
  51 static inline void pat_disable(const char *reason)
  52 {
  53         (void)reason;
  54 }
  55 #endif
  56
  57
  58 int pat_debug_enable;
  59
  60 static int __init pat_debug_setup(char *str)
  61 {
  62         pat_debug_enable = 1;
  63         return 0;
  64 }
  65 __setup("debugpat", pat_debug_setup);
  66
  67 static u64 __read_mostly boot_pat_state;
  68
  69 enum {
  70         PAT_UC = 0,             /* uncached */
  71         PAT_WC = 1,             /* Write combining */
  72         PAT_WT = 4,             /* Write Through */
  73         PAT_WP = 5,             /* Write Protected */
  74         PAT_WB = 6,             /* Write Back (default) */
  75         PAT_UC_MINUS = 7,       /* UC, but can be overriden by MTRR */
  76 };
  77
  78 #define PAT(x, y)       ((u64)PAT_ ## y << ((x)*8))
  79
  80 void pat_init(void)
  81 {
  82         u64 pat;
  83         bool boot_cpu = !boot_pat_state;
  84
  85         if (!pat_enabled)
  86                 return;
  87
  88         if (!cpu_has_pat) {
  89                 if (!boot_pat_state) {
  90                         pat_disable("PAT not supported by CPU.");
  91                         return;
  92                 } else {
  93                         /*
  94                          * If this happens we are on a secondary CPU, but
  95                          * switched to PAT on the boot CPU. We have no way to
  96                          * undo PAT.
  97                          */
  98                         printk(KERN_ERR "PAT enabled, "
  99                                "but not supported by secondary CPU\n");
 100                         BUG();
 101                 }
 102         }
 103
 104         /* Set PWT to Write-Combining. All other bits stay the same */
 105         /*
 106          * PTE encoding used in Linux:
 107          *      PAT
 108          *      |PCD
 109          *      ||PWT
 110          *      |||
 111          *      000 WB          _PAGE_CACHE_WB
 112          *      001 WC          _PAGE_CACHE_WC
 113          *      010 UC-         _PAGE_CACHE_UC_MINUS
 114          *      011 UC          _PAGE_CACHE_UC
 115          * PAT bit unused
 116          */
 117         pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) |
 118               PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC);
 119
 120         /* Boot CPU check */
 121         if (!boot_pat_state)
 122                 rdmsrl(MSR_IA32_CR_PAT, boot_pat_state);
 123
 124         wrmsrl(MSR_IA32_CR_PAT, pat);
 125
 126         if (boot_cpu)
 127                 printk(KERN_INFO "x86 PAT enabled: cpu %d, old 0x%Lx, new 0x%Lx\n",
 128                        smp_processor_id(), boot_pat_state, pat);
 129 }
 130
 131 #undef PAT
 132
 133 static DEFINE_SPINLOCK(memtype_lock);   /* protects memtype accesses */
 134
 135 /*
 136  * Does intersection of PAT memory type and MTRR memory type and returns
 137  * the resulting memory type as PAT understands it.
 138  * (Type in pat and mtrr will not have same value)
 139  * The intersection is based on "Effective Memory Type" tables in IA-32
 140  * SDM vol 3a
 141  */
 142 static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
 143 {
 144         /*
 145          * Look for MTRR hint to get the effective type in case where PAT
 146          * request is for WB.
 147          */
 148         if (req_type == _PAGE_CACHE_WB) {
 149                 u8 mtrr_type;
 150
 151                 mtrr_type = mtrr_type_lookup(start, end);
 152                 if (mtrr_type != MTRR_TYPE_WRBACK)
 153                         return _PAGE_CACHE_UC_MINUS;
 154
 155                 return _PAGE_CACHE_WB;
 156         }
 157
 158         return req_type;
 159 }
 160
 161 static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end)
 162 {
 163         int ram_page = 0, not_rampage = 0;
 164         unsigned long page_nr;
 165
 166         for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
 167              ++page_nr) {
 168                 /*
 169                  * For legacy reasons, physical address range in the legacy ISA
 170                  * region is tracked as non-RAM. This will allow users of
 171                  * /dev/mem to map portions of legacy ISA region, even when
 172                  * some of those portions are listed(or not even listed) with
 173                  * different e820 types(RAM/reserved/..)
 174                  */
 175                 if (page_nr >= (ISA_END_ADDRESS >> PAGE_SHIFT) &&
 176                     page_is_ram(page_nr))
 177                         ram_page = 1;
 178                 else
 179                         not_rampage = 1;
 180
 181                 if (ram_page == not_rampage)
 182                         return -1;
 183         }
 184
 185         return ram_page;
 186 }
 187
 188 /*
 189  * For RAM pages, we use page flags to mark the pages with appropriate type.
 190  * Here we do two pass:
 191  * - Find the memtype of all the pages in the range, look for any conflicts
 192  * - In case of no conflicts, set the new memtype for pages in the range
 193  */
 194 static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type,
 195                                   unsigned long *new_type)
 196 {
 197         struct page *page;
 198         u64 pfn;
 199
 200         if (req_type == _PAGE_CACHE_UC) {
 201                 /* We do not support strong UC */
 202                 WARN_ON_ONCE(1);
 203                 req_type = _PAGE_CACHE_UC_MINUS;
 204         }
 205
 206         for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
 207                 unsigned long type;
 208
 209                 page = pfn_to_page(pfn);
 210                 type = get_page_memtype(page);
 211                 if (type != -1) {
 212                         printk(KERN_INFO "reserve_ram_pages_type failed "
 213                                 "0x%Lx-0x%Lx, track 0x%lx, req 0x%lx\n",
 214                                 start, end, type, req_type);
 215                         if (new_type)
 216                                 *new_type = type;
 217
 218                         return -EBUSY;
 219                 }
 220         }
 221
 222         if (new_type)
 223                 *new_type = req_type;
 224
 225         for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
 226                 page = pfn_to_page(pfn);
 227                 set_page_memtype(page, req_type);
 228         }
 229         return 0;
 230 }
 231
 232 static int free_ram_pages_type(u64 start, u64 end)
 233 {
 234         struct page *page;
 235         u64 pfn;
 236
 237         for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) {
 238                 page = pfn_to_page(pfn);
 239                 set_page_memtype(page, -1);
 240         }
 241         return 0;
 242 }
 243
 244 /*
 245  * req_type typically has one of the:
 246  * - _PAGE_CACHE_WB
 247  * - _PAGE_CACHE_WC
 248  * - _PAGE_CACHE_UC_MINUS
 249  * - _PAGE_CACHE_UC
 250  *
 251  * If new_type is NULL, function will return an error if it cannot reserve the
 252  * region with req_type. If new_type is non-NULL, function will return
 253  * available type in new_type in case of no error. In case of any error
 254  * it will return a negative return value.
 255  */
 256 int reserve_memtype(u64 start, u64 end, unsigned long req_type,
 257                     unsigned long *new_type)
 258 {
 259         struct memtype *new;
 260         unsigned long actual_type;
 261         int is_range_ram;
 262         int err = 0;
 263
 264         BUG_ON(start >= end); /* end is exclusive */
 265
 266         if (!pat_enabled) {
 267                 /* This is identical to page table setting without PAT */
 268                 if (new_type) {
 269                         if (req_type == _PAGE_CACHE_WC)
 270                                 *new_type = _PAGE_CACHE_UC_MINUS;
 271                         else
 272                                 *new_type = req_type & _PAGE_CACHE_MASK;
 273                 }
 274                 return 0;
 275         }
 276
 277         /* Low ISA region is always mapped WB in page table. No need to track */
 278         if (x86_platform.is_untracked_pat_range(start, end)) {
 279                 if (new_type)
 280                         *new_type = _PAGE_CACHE_WB;
 281                 return 0;
 282         }
 283
 284         /*
 285          * Call mtrr_lookup to get the type hint. This is an
 286          * optimization for /dev/mem mmap'ers into WB memory (BIOS
 287          * tools and ACPI tools). Use WB request for WB memory and use
 288          * UC_MINUS otherwise.
 289          */
 290         actual_type = pat_x_mtrr_type(start, end, req_type & _PAGE_CACHE_MASK);
 291
 292         if (new_type)
 293                 *new_type = actual_type;
 294
 295         is_range_ram = pat_pagerange_is_ram(start, end);
 296         if (is_range_ram == 1) {
 297
 298                 err = reserve_ram_pages_type(start, end, req_type, new_type);
 299
 300                 return err;
 301         } else if (is_range_ram < 0) {
 302                 return -EINVAL;
 303         }
 304
 305         new  = kzalloc(sizeof(struct memtype), GFP_KERNEL);
 306         if (!new)
 307                 return -ENOMEM;
 308
 309         new->start      = start;
 310         new->end        = end;
 311         new->type       = actual_type;
 312
 313         spin_lock(&memtype_lock);
 314
 315         err = rbt_memtype_check_insert(new, new_type);
 316         if (err) {
 317                 printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
 318                        "track %s, req %s\n",
 319                        start, end, cattr_name(new->type), cattr_name(req_type));
 320                 kfree(new);
 321                 spin_unlock(&memtype_lock);
 322
 323                 return err;
 324         }
 325
 326         spin_unlock(&memtype_lock);
 327
 328         dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
 329                 start, end, cattr_name(new->type), cattr_name(req_type),
 330                 new_type ? cattr_name(*new_type) : "-");
 331
 332         return err;
 333 }
 334
 335 int free_memtype(u64 start, u64 end)
 336 {
 337         int err = -EINVAL;
 338         int is_range_ram;
 339         struct memtype *entry;
 340
 341         if (!pat_enabled)
 342                 return 0;
 343
 344         /* Low ISA region is always mapped WB. No need to track */
 345         if (x86_platform.is_untracked_pat_range(start, end))
 346                 return 0;
 347
 348         is_range_ram = pat_pagerange_is_ram(start, end);
 349         if (is_range_ram == 1) {
 350
 351                 err = free_ram_pages_type(start, end);
 352
 353                 return err;
 354         } else if (is_range_ram < 0) {
 355                 return -EINVAL;
 356         }
 357
 358         spin_lock(&memtype_lock);
 359         entry = rbt_memtype_erase(start, end);
 360         spin_unlock(&memtype_lock);
 361
 362         if (!entry) {
 363                 printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
 364                         current->comm, current->pid, start, end);
 365                 return -EINVAL;
 366         }
 367
 368         kfree(entry);
 369
 370         dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end);
 371
 372         return 0;
 373 }
 374
 375
 376 /**
 377  * lookup_memtype - Looksup the memory type for a physical address
 378  * @paddr: physical address of which memory type needs to be looked up
 379  *
 380  * Only to be called when PAT is enabled
 381  *
 382  * Returns _PAGE_CACHE_WB, _PAGE_CACHE_WC, _PAGE_CACHE_UC_MINUS or
 383  * _PAGE_CACHE_UC
 384  */
 385 static unsigned long lookup_memtype(u64 paddr)
 386 {
 387         int rettype = _PAGE_CACHE_WB;
 388         struct memtype *entry;
 389
 390         if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE))
 391                 return rettype;
 392
 393         if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) {
 394                 struct page *page;
 395                 page = pfn_to_page(paddr >> PAGE_SHIFT);
 396                 rettype = get_page_memtype(page);
 397                 /*
 398                  * -1 from get_page_memtype() implies RAM page is in its
 399                  * default state and not reserved, and hence of type WB
 400                  */
 401                 if (rettype == -1)
 402                         rettype = _PAGE_CACHE_WB;
 403
 404                 return rettype;
 405         }
 406
 407         spin_lock(&memtype_lock);
 408
 409         entry = rbt_memtype_lookup(paddr);
 410         if (entry != NULL)
 411                 rettype = entry->type;
 412         else
 413                 rettype = _PAGE_CACHE_UC_MINUS;
 414
 415         spin_unlock(&memtype_lock);
 416         return rettype;
 417 }
 418
 419 /**
 420  * io_reserve_memtype - Request a memory type mapping for a region of memory
 421  * @start: start (physical address) of the region
 422  * @end: end (physical address) of the region
 423  * @type: A pointer to memtype, with requested type. On success, requested
 424  * or any other compatible type that was available for the region is returned
 425  *
 426  * On success, returns 0
 427  * On failure, returns non-zero
 428  */
 429 int io_reserve_memtype(resource_size_t start, resource_size_t end,
 430                         unsigned long *type)
 431 {
 432         resource_size_t size = end - start;
 433         unsigned long req_type = *type;
 434         unsigned long new_type;
 435         int ret;
 436
 437         WARN_ON_ONCE(iomem_map_sanity_check(start, size));
 438
 439         ret = reserve_memtype(start, end, req_type, &new_type);
 440         if (ret)
 441                 goto out_err;
 442
 443         if (!is_new_memtype_allowed(start, size, req_type, new_type))
 444                 goto out_free;
 445
 446         if (kernel_map_sync_memtype(start, size, new_type) < 0)
 447                 goto out_free;
 448
 449         *type = new_type;
 450         return 0;
 451
 452 out_free:
 453         free_memtype(start, end);
 454         ret = -EBUSY;
 455 out_err:
 456         return ret;
 457 }
 458
 459 /**
 460  * io_free_memtype - Release a memory type mapping for a region of memory
 461  * @start: start (physical address) of the region
 462  * @end: end (physical address) of the region
 463  */
 464 void io_free_memtype(resource_size_t start, resource_size_t end)
 465 {
 466         free_memtype(start, end);
 467 }
 468
 469 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 470                                 unsigned long size, pgprot_t vma_prot)
 471 {
 472         return vma_prot;
 473 }
 474
 475 #ifdef CONFIG_STRICT_DEVMEM
 476 /* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM*/
 477 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 478 {
 479         return 1;
 480 }
 481 #else
 482 /* This check is needed to avoid cache aliasing when PAT is enabled */
 483 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 484 {
 485         u64 from = ((u64)pfn) << PAGE_SHIFT;
 486         u64 to = from + size;
 487         u64 cursor = from;
 488
 489         if (!pat_enabled)
 490                 return 1;
 491
 492         while (cursor < to) {
 493                 if (!devmem_is_allowed(pfn)) {
 494                         printk(KERN_INFO
 495                 "Program %s tried to access /dev/mem between %Lx->%Lx.\n",
 496                                 current->comm, from, to);
 497                         return 0;
 498                 }
 499                 cursor += PAGE_SIZE;
 500                 pfn++;
 501         }
 502         return 1;
 503 }
 504 #endif /* CONFIG_STRICT_DEVMEM */
 505
 506 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 507                                 unsigned long size, pgprot_t *vma_prot)
 508 {
 509         unsigned long flags = _PAGE_CACHE_WB;
 510
 511         if (!range_is_allowed(pfn, size))
 512                 return 0;
 513
 514         if (file->f_flags & O_DSYNC)
 515                 flags = _PAGE_CACHE_UC_MINUS;
 516
 517 #ifdef CONFIG_X86_32
 518         /*
 519          * On the PPro and successors, the MTRRs are used to set
 520          * memory types for physical addresses outside main memory,
 521          * so blindly setting UC or PWT on those pages is wrong.
 522          * For Pentiums and earlier, the surround logic should disable
 523          * caching for the high addresses through the KEN pin, but
 524          * we maintain the tradition of paranoia in this code.
 525          */
 526         if (!pat_enabled &&
 527             !(boot_cpu_has(X86_FEATURE_MTRR) ||
 528               boot_cpu_has(X86_FEATURE_K6_MTRR) ||
 529               boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
 530               boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
 531             (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
 532                 flags = _PAGE_CACHE_UC;
 533         }
 534 #endif
 535
 536         *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
 537                              flags);
 538         return 1;
 539 }
 540
 541 /*
 542  * Change the memory type for the physial address range in kernel identity
 543  * mapping space if that range is a part of identity map.
 544  */
 545 int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags)
 546 {
 547         unsigned long id_sz;
 548
 549         if (base >= __pa(high_memory))
 550                 return 0;
 551
 552         id_sz = (__pa(high_memory) < base + size) ?
 553                                 __pa(high_memory) - base :
 554                                 size;
 555
 556         if (ioremap_change_attr((unsigned long)__va(base), id_sz, flags) < 0) {
 557                 printk(KERN_INFO
 558                         "%s:%d ioremap_change_attr failed %s "
 559                         "for %Lx-%Lx\n",
 560                         current->comm, current->pid,
 561                         cattr_name(flags),
 562                         base, (unsigned long long)(base + size));
 563                 return -EINVAL;
 564         }
 565         return 0;
 566 }
 567
 568 /*
 569  * Internal interface to reserve a range of physical memory with prot.
 570  * Reserved non RAM regions only and after successful reserve_memtype,
 571  * this func also keeps identity mapping (if any) in sync with this new prot.
 572  */
 573 static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
 574                                 int strict_prot)
 575 {
 576         int is_ram = 0;
 577         int ret;
 578         unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
 579         unsigned long flags = want_flags;
 580
 581         is_ram = pat_pagerange_is_ram(paddr, paddr + size);
 582
 583         /*
 584          * reserve_pfn_range() for RAM pages. We do not refcount to keep
 585          * track of number of mappings of RAM pages. We can assert that
 586          * the type requested matches the type of first page in the range.
 587          */
 588         if (is_ram) {
 589                 if (!pat_enabled)
 590                         return 0;
 591
 592                 flags = lookup_memtype(paddr);
 593                 if (want_flags != flags) {
 594                         printk(KERN_WARNING
 595                         "%s:%d map pfn RAM range req %s for %Lx-%Lx, got %s\n",
 596                                 current->comm, current->pid,
 597                                 cattr_name(want_flags),
 598                                 (unsigned long long)paddr,
 599                                 (unsigned long long)(paddr + size),
 600                                 cattr_name(flags));
 601                         *vma_prot = __pgprot((pgprot_val(*vma_prot) &
 602                                               (~_PAGE_CACHE_MASK)) |
 603                                              flags);
 604                 }
 605                 return 0;
 606         }
 607
 608         ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
 609         if (ret)
 610                 return ret;
 611
 612         if (flags != want_flags) {
 613                 if (strict_prot ||
 614                     !is_new_memtype_allowed(paddr, size, want_flags, flags)) {
 615                         free_memtype(paddr, paddr + size);
 616                         printk(KERN_ERR "%s:%d map pfn expected mapping type %s"
 617                                 " for %Lx-%Lx, got %s\n",
 618                                 current->comm, current->pid,
 619                                 cattr_name(want_flags),
 620                                 (unsigned long long)paddr,
 621                                 (unsigned long long)(paddr + size),
 622                                 cattr_name(flags));
 623                         return -EINVAL;
 624                 }
 625                 /*
 626                  * We allow returning different type than the one requested in
 627                  * non strict case.
 628                  */
 629                 *vma_prot = __pgprot((pgprot_val(*vma_prot) &
 630                                       (~_PAGE_CACHE_MASK)) |
 631                                      flags);
 632         }
 633
 634         if (kernel_map_sync_memtype(paddr, size, flags) < 0) {
 635                 free_memtype(paddr, paddr + size);
 636                 return -EINVAL;
 637         }
 638         return 0;
 639 }
 640
 641 /*
 642  * Internal interface to free a range of physical memory.
 643  * Frees non RAM regions only.
 644  */
 645 static void free_pfn_range(u64 paddr, unsigned long size)
 646 {
 647         int is_ram;
 648
 649         is_ram = pat_pagerange_is_ram(paddr, paddr + size);
 650         if (is_ram == 0)
 651                 free_memtype(paddr, paddr + size);
 652 }
 653
 654 /*
 655  * track_pfn_vma_copy is called when vma that is covering the pfnmap gets
 656  * copied through copy_page_range().
 657  *
 658  * If the vma has a linear pfn mapping for the entire range, we get the prot
 659  * from pte and reserve the entire vma range with single reserve_pfn_range call.
 660  */
 661 int track_pfn_vma_copy(struct vm_area_struct *vma)
 662 {
 663         resource_size_t paddr;
 664         unsigned long prot;
 665         unsigned long vma_size = vma->vm_end - vma->vm_start;
 666         pgprot_t pgprot;
 667
 668         if (is_linear_pfn_mapping(vma)) {
 669                 /*
 670                  * reserve the whole chunk covered by vma. We need the
 671                  * starting address and protection from pte.
 672                  */
 673                 if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
 674                         WARN_ON_ONCE(1);
 675                         return -EINVAL;
 676                 }
 677                 pgprot = __pgprot(prot);
 678                 return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
 679         }
 680
 681         return 0;
 682 }
 683
 684 /*
 685  * track_pfn_vma_new is called when a _new_ pfn mapping is being established
 686  * for physical range indicated by pfn and size.
 687  *
 688  * prot is passed in as a parameter for the new mapping. If the vma has a
 689  * linear pfn mapping for the entire range reserve the entire vma range with
 690  * single reserve_pfn_range call.
 691  */
 692 int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
 693                         unsigned long pfn, unsigned long size)
 694 {
 695         unsigned long flags;
 696         resource_size_t paddr;
 697         unsigned long vma_size = vma->vm_end - vma->vm_start;
 698
 699         if (is_linear_pfn_mapping(vma)) {
 700                 /* reserve the whole chunk starting from vm_pgoff */
 701                 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
 702                 return reserve_pfn_range(paddr, vma_size, prot, 0);
 703         }
 704
 705         if (!pat_enabled)
 706                 return 0;
 707
 708         /* for vm_insert_pfn and friends, we set prot based on lookup */
 709         flags = lookup_memtype(pfn << PAGE_SHIFT);
 710         *prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
 711                          flags);
 712
 713         return 0;
 714 }
 715
 716 /*
 717  * untrack_pfn_vma is called while unmapping a pfnmap for a region.
 718  * untrack can be called for a specific region indicated by pfn and size or
 719  * can be for the entire vma (in which case size can be zero).
 720  */
 721 void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
 722                         unsigned long size)
 723 {
 724         resource_size_t paddr;
 725         unsigned long vma_size = vma->vm_end - vma->vm_start;
 726
 727         if (is_linear_pfn_mapping(vma)) {
 728                 /* free the whole chunk starting from vm_pgoff */
 729                 paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
 730                 free_pfn_range(paddr, vma_size);
 731                 return;
 732         }
 733 }
 734
 735 pgprot_t pgprot_writecombine(pgprot_t prot)
 736 {
 737         if (pat_enabled)
 738                 return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
 739         else
 740                 return pgprot_noncached(prot);
 741 }
 742 EXPORT_SYMBOL_GPL(pgprot_writecombine);
 743
 744 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
 745
 746 static struct memtype *memtype_get_idx(loff_t pos)
 747 {
 748         struct memtype *print_entry;
 749         int ret;
 750
 751         print_entry  = kzalloc(sizeof(struct memtype), GFP_KERNEL);
 752         if (!print_entry)
 753                 return NULL;
 754
 755         spin_lock(&memtype_lock);
 756         ret = rbt_memtype_copy_nth_element(print_entry, pos);
 757         spin_unlock(&memtype_lock);
 758
 759         if (!ret) {
 760                 return print_entry;
 761         } else {
 762                 kfree(print_entry);
 763                 return NULL;
 764         }
 765 }
 766
 767 static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
 768 {
 769         if (*pos == 0) {
 770                 ++*pos;
 771                 seq_printf(seq, "PAT memtype list:\n");
 772         }
 773
 774         return memtype_get_idx(*pos);
 775 }
 776
 777 static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 778 {
 779         ++*pos;
 780         return memtype_get_idx(*pos);
 781 }
 782
 783 static void memtype_seq_stop(struct seq_file *seq, void *v)
 784 {
 785 }
 786
 787 static int memtype_seq_show(struct seq_file *seq, void *v)
 788 {
 789         struct memtype *print_entry = (struct memtype *)v;
 790
 791         seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),
 792                         print_entry->start, print_entry->end);
 793         kfree(print_entry);
 794
 795         return 0;
 796 }
 797
 798 static const struct seq_operations memtype_seq_ops = {
 799         .start = memtype_seq_start,
 800         .next  = memtype_seq_next,
 801         .stop  = memtype_seq_stop,
 802         .show  = memtype_seq_show,
 803 };
 804
 805 static int memtype_seq_open(struct inode *inode, struct file *file)
 806 {
 807         return seq_open(file, &memtype_seq_ops);
 808 }
 809
 810 static const struct file_operations memtype_fops = {
 811         .open    = memtype_seq_open,
 812         .read    = seq_read,
 813         .llseek  = seq_lseek,
 814         .release = seq_release,
 815 };
 816
 817 static int __init pat_memtype_list_init(void)
 818 {
 819         if (pat_enabled) {
 820                 debugfs_create_file("pat_memtype_list", S_IRUSR,
 821                                     arch_debugfs_dir, NULL, &memtype_fops);
 822         }
 823         return 0;
 824 }
 825
 826 late_initcall(pat_memtype_list_init);
 827
 828 #endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */