arch/x86/mm/ioremap.c

   1 /*
   2  * Re-map IO memory to kernel address space so that we can access it.
   3  * This is needed for high PCI addresses that aren't mapped in the
   4  * 640k-1MB IO memory area on PC's
   5  *
   6  * (C) Copyright 1995 1996 Linus Torvalds
   7  */
   8
   9 #include <linux/bootmem.h>
  10 #include <linux/init.h>
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/vmalloc.h>
  15
  16 #include <asm/cacheflush.h>
  17 #include <asm/e820.h>
  18 #include <asm/fixmap.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/tlbflush.h>
  21 #include <asm/pgalloc.h>
  22 #include <asm/pat.h>
  23
  24 #ifdef CONFIG_X86_64
  25
  26 unsigned long __phys_addr(unsigned long x)
  27 {
  28         if (x >= __START_KERNEL_map)
  29                 return x - __START_KERNEL_map + phys_base;
  30         return x - PAGE_OFFSET;
  31 }
  32 EXPORT_SYMBOL(__phys_addr);
  33
  34 static inline int phys_addr_valid(unsigned long addr)
  35 {
  36         return addr < (1UL << boot_cpu_data.x86_phys_bits);
  37 }
  38
  39 #else
  40
  41 static inline int phys_addr_valid(unsigned long addr)
  42 {
  43         return 1;
  44 }
  45
  46 #endif
  47
  48 int page_is_ram(unsigned long pagenr)
  49 {
  50         resource_size_t addr, end;
  51         int i;
  52
  53         /*
  54          * A special case is the first 4Kb of memory;
  55          * This is a BIOS owned area, not kernel ram, but generally
  56          * not listed as such in the E820 table.
  57          */
  58         if (pagenr == 0)
  59                 return 0;
  60
  61         /*
  62          * Second special case: Some BIOSen report the PC BIOS
  63          * area (640->1Mb) as ram even though it is not.
  64          */
  65         if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
  66                     pagenr < (BIOS_END >> PAGE_SHIFT))
  67                 return 0;
  68
  69         for (i = 0; i < e820.nr_map; i++) {
  70                 /*
  71                  * Not usable memory:
  72                  */
  73                 if (e820.map[i].type != E820_RAM)
  74                         continue;
  75                 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
  76                 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
  77
  78
  79                 if ((pagenr >= addr) && (pagenr < end))
  80                         return 1;
  81         }
  82         return 0;
  83 }
  84
  85 /*
  86  * Fix up the linear direct mapping of the kernel to avoid cache attribute
  87  * conflicts.
  88  */
  89 int ioremap_change_attr(unsigned long vaddr, unsigned long size,
  90                                unsigned long prot_val)
  91 {
  92         unsigned long nrpages = size >> PAGE_SHIFT;
  93         int err;
  94
  95         switch (prot_val) {
  96         case _PAGE_CACHE_UC:
  97         default:
  98                 err = _set_memory_uc(vaddr, nrpages);
  99                 break;
 100         case _PAGE_CACHE_WC:
 101                 err = _set_memory_wc(vaddr, nrpages);
 102                 break;
 103         case _PAGE_CACHE_WB:
 104                 err = _set_memory_wb(vaddr, nrpages);
 105                 break;
 106         }
 107
 108         return err;
 109 }
 110
 111 /*
 112  * Remap an arbitrary physical address space into the kernel virtual
 113  * address space. Needed when the kernel wants to access high addresses
 114  * directly.
 115  *
 116  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 117  * have to convert them into an offset in a page-aligned mapping, but the
 118  * caller shouldn't need to know that small detail.
 119  */
 120 static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 121                 unsigned long size, unsigned long prot_val, void *caller)
 122 {
 123         unsigned long pfn, offset, vaddr;
 124         resource_size_t last_addr;
 125         struct vm_struct *area;
 126         unsigned long new_prot_val;
 127         pgprot_t prot;
 128         int retval;
 129
 130         /* Don't allow wraparound or zero size */
 131         last_addr = phys_addr + size - 1;
 132         if (!size || last_addr < phys_addr)
 133                 return NULL;
 134
 135         if (!phys_addr_valid(phys_addr)) {
 136                 printk(KERN_WARNING "ioremap: invalid physical address %llx\n",
 137                        (unsigned long long)phys_addr);
 138                 WARN_ON_ONCE(1);
 139                 return NULL;
 140         }
 141
 142         /*
 143          * Don't remap the low PCI/ISA area, it's always mapped..
 144          */
 145         if (is_ISA_range(phys_addr, last_addr))
 146                 return (__force void __iomem *)phys_to_virt(phys_addr);
 147
 148         /*
 149          * Don't allow anybody to remap normal RAM that we're using..
 150          */
 151         for (pfn = phys_addr >> PAGE_SHIFT;
 152                                 (pfn << PAGE_SHIFT) < (last_addr & PAGE_MASK);
 153                                 pfn++) {
 154
 155                 int is_ram = page_is_ram(pfn);
 156
 157                 if (is_ram && pfn_valid(pfn) && !PageReserved(pfn_to_page(pfn)))
 158                         return NULL;
 159                 WARN_ON_ONCE(is_ram);
 160         }
 161
 162         /*
 163          * Mappings have to be page-aligned
 164          */
 165         offset = phys_addr & ~PAGE_MASK;
 166         phys_addr &= PAGE_MASK;
 167         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 168
 169         retval = reserve_memtype(phys_addr, phys_addr + size,
 170                                                 prot_val, &new_prot_val);
 171         if (retval) {
 172                 pr_debug("Warning: reserve_memtype returned %d\n", retval);
 173                 return NULL;
 174         }
 175
 176         if (prot_val != new_prot_val) {
 177                 /*
 178                  * Do not fallback to certain memory types with certain
 179                  * requested type:
 180                  * - request is uc-, return cannot be write-back
 181                  * - request is uc-, return cannot be write-combine
 182                  * - request is write-combine, return cannot be write-back
 183                  */
 184                 if ((prot_val == _PAGE_CACHE_UC_MINUS &&
 185                      (new_prot_val == _PAGE_CACHE_WB ||
 186                       new_prot_val == _PAGE_CACHE_WC)) ||
 187                     (prot_val == _PAGE_CACHE_WC &&
 188                      new_prot_val == _PAGE_CACHE_WB)) {
 189                         pr_debug(
 190                 "ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n",
 191                                 (unsigned long long)phys_addr,
 192                                 (unsigned long long)(phys_addr + size),
 193                                 prot_val, new_prot_val);
 194                         free_memtype(phys_addr, phys_addr + size);
 195                         return NULL;
 196                 }
 197                 prot_val = new_prot_val;
 198         }
 199
 200         switch (prot_val) {
 201         case _PAGE_CACHE_UC:
 202         default:
 203                 prot = PAGE_KERNEL_NOCACHE;
 204                 break;
 205         case _PAGE_CACHE_UC_MINUS:
 206                 prot = PAGE_KERNEL_UC_MINUS;
 207                 break;
 208         case _PAGE_CACHE_WC:
 209                 prot = PAGE_KERNEL_WC;
 210                 break;
 211         case _PAGE_CACHE_WB:
 212                 prot = PAGE_KERNEL;
 213                 break;
 214         }
 215
 216         /*
 217          * Ok, go for it..
 218          */
 219         area = get_vm_area_caller(size, VM_IOREMAP, caller);
 220         if (!area)
 221                 return NULL;
 222         area->phys_addr = phys_addr;
 223         vaddr = (unsigned long) area->addr;
 224         if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
 225                 free_memtype(phys_addr, phys_addr + size);
 226                 free_vm_area(area);
 227                 return NULL;
 228         }
 229
 230         if (ioremap_change_attr(vaddr, size, prot_val) < 0) {
 231                 free_memtype(phys_addr, phys_addr + size);
 232                 vunmap(area->addr);
 233                 return NULL;
 234         }
 235
 236         return (void __iomem *) (vaddr + offset);
 237 }
 238
 239 /**
 240  * ioremap_nocache     -   map bus memory into CPU space
 241  * @offset:    bus address of the memory
 242  * @size:      size of the resource to map
 243  *
 244  * ioremap_nocache performs a platform specific sequence of operations to
 245  * make bus memory CPU accessible via the readb/readw/readl/writeb/
 246  * writew/writel functions and the other mmio helpers. The returned
 247  * address is not guaranteed to be usable directly as a virtual
 248  * address.
 249  *
 250  * This version of ioremap ensures that the memory is marked uncachable
 251  * on the CPU as well as honouring existing caching rules from things like
 252  * the PCI bus. Note that there are other caches and buffers on many
 253  * busses. In particular driver authors should read up on PCI writes
 254  *
 255  * It's useful if some control registers are in such an area and
 256  * write combining or read caching is not desirable:
 257  *
 258  * Must be freed with iounmap.
 259  */
 260 void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
 261 {
 262         /*
 263          * Ideally, this should be:
 264          *      pat_enabled ? _PAGE_CACHE_UC : _PAGE_CACHE_UC_MINUS;
 265          *
 266          * Till we fix all X drivers to use ioremap_wc(), we will use
 267          * UC MINUS.
 268          */
 269         unsigned long val = _PAGE_CACHE_UC_MINUS;
 270
 271         return __ioremap_caller(phys_addr, size, val,
 272                                 __builtin_return_address(0));
 273 }
 274 EXPORT_SYMBOL(ioremap_nocache);
 275
 276 /**
 277  * ioremap_wc   -       map memory into CPU space write combined
 278  * @offset:     bus address of the memory
 279  * @size:       size of the resource to map
 280  *
 281  * This version of ioremap ensures that the memory is marked write combining.
 282  * Write combining allows faster writes to some hardware devices.
 283  *
 284  * Must be freed with iounmap.
 285  */
 286 void __iomem *ioremap_wc(unsigned long phys_addr, unsigned long size)
 287 {
 288         if (pat_enabled)
 289                 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WC,
 290                                         __builtin_return_address(0));
 291         else
 292                 return ioremap_nocache(phys_addr, size);
 293 }
 294 EXPORT_SYMBOL(ioremap_wc);
 295
 296 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
 297 {
 298         return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WB,
 299                                 __builtin_return_address(0));
 300 }
 301 EXPORT_SYMBOL(ioremap_cache);
 302
 303 /**
 304  * iounmap - Free a IO remapping
 305  * @addr: virtual address from ioremap_*
 306  *
 307  * Caller must ensure there is only one unmapping for the same pointer.
 308  */
 309 void iounmap(volatile void __iomem *addr)
 310 {
 311         struct vm_struct *p, *o;
 312
 313         if ((void __force *)addr <= high_memory)
 314                 return;
 315
 316         /*
 317          * __ioremap special-cases the PCI/ISA range by not instantiating a
 318          * vm_area and by simply returning an address into the kernel mapping
 319          * of ISA space.   So handle that here.
 320          */
 321         if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) &&
 322             (void __force *)addr < phys_to_virt(ISA_END_ADDRESS))
 323                 return;
 324
 325         addr = (volatile void __iomem *)
 326                 (PAGE_MASK & (unsigned long __force)addr);
 327
 328         /* Use the vm area unlocked, assuming the caller
 329            ensures there isn't another iounmap for the same address
 330            in parallel. Reuse of the virtual address is prevented by
 331            leaving it in the global lists until we're done with it.
 332            cpa takes care of the direct mappings. */
 333         read_lock(&vmlist_lock);
 334         for (p = vmlist; p; p = p->next) {
 335                 if (p->addr == (void __force *)addr)
 336                         break;
 337         }
 338         read_unlock(&vmlist_lock);
 339
 340         if (!p) {
 341                 printk(KERN_ERR "iounmap: bad address %p\n", addr);
 342                 dump_stack();
 343                 return;
 344         }
 345
 346         free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p));
 347
 348         /* Finally remove it */
 349         o = remove_vm_area((void __force *)addr);
 350         BUG_ON(p != o || o == NULL);
 351         kfree(p);
 352 }
 353 EXPORT_SYMBOL(iounmap);
 354
 355 /*
 356  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
 357  * access
 358  */
 359 void *xlate_dev_mem_ptr(unsigned long phys)
 360 {
 361         void *addr;
 362         unsigned long start = phys & PAGE_MASK;
 363
 364         /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */
 365         if (page_is_ram(start >> PAGE_SHIFT))
 366                 return __va(phys);
 367
 368         addr = (void __force *)ioremap(start, PAGE_SIZE);
 369         if (addr)
 370                 addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK));
 371
 372         return addr;
 373 }
 374
 375 void unxlate_dev_mem_ptr(unsigned long phys, void *addr)
 376 {
 377         if (page_is_ram(phys >> PAGE_SHIFT))
 378                 return;
 379
 380         iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
 381         return;
 382 }
 383
 384 int __initdata early_ioremap_debug;
 385
 386 static int __init early_ioremap_debug_setup(char *str)
 387 {
 388         early_ioremap_debug = 1;
 389
 390         return 0;
 391 }
 392 early_param("early_ioremap_debug", early_ioremap_debug_setup);
 393
 394 static __initdata int after_paging_init;
 395 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;
 396
 397 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 398 {
 399         /* Don't assume we're using swapper_pg_dir at this point */
 400         pgd_t *base = __va(read_cr3());
 401         pgd_t *pgd = &base[pgd_index(addr)];
 402         pud_t *pud = pud_offset(pgd, addr);
 403         pmd_t *pmd = pmd_offset(pud, addr);
 404
 405         return pmd;
 406 }
 407
 408 static inline pte_t * __init early_ioremap_pte(unsigned long addr)
 409 {
 410         return &bm_pte[pte_index(addr)];
 411 }
 412
 413 void __init early_ioremap_init(void)
 414 {
 415         pmd_t *pmd;
 416
 417         if (early_ioremap_debug)
 418                 printk(KERN_INFO "early_ioremap_init()\n");
 419
 420         pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
 421         memset(bm_pte, 0, sizeof(bm_pte));
 422         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 423
 424         /*
 425          * The boot-ioremap range spans multiple pmds, for which
 426          * we are not prepared:
 427          */
 428         if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 429                 WARN_ON(1);
 430                 printk(KERN_WARNING "pmd %p != %p\n",
 431                        pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
 432                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 433                         fix_to_virt(FIX_BTMAP_BEGIN));
 434                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 435                         fix_to_virt(FIX_BTMAP_END));
 436
 437                 printk(KERN_WARNING "FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 438                 printk(KERN_WARNING "FIX_BTMAP_BEGIN:     %d\n",
 439                        FIX_BTMAP_BEGIN);
 440         }
 441 }
 442
 443 void __init early_ioremap_clear(void)
 444 {
 445         pmd_t *pmd;
 446
 447         if (early_ioremap_debug)
 448                 printk(KERN_INFO "early_ioremap_clear()\n");
 449
 450         pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
 451         pmd_clear(pmd);
 452         paravirt_release_pte(__pa(bm_pte) >> PAGE_SHIFT);
 453         __flush_tlb_all();
 454 }
 455
 456 void __init early_ioremap_reset(void)
 457 {
 458         enum fixed_addresses idx;
 459         unsigned long addr, phys;
 460         pte_t *pte;
 461
 462         after_paging_init = 1;
 463         for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
 464                 addr = fix_to_virt(idx);
 465                 pte = early_ioremap_pte(addr);
 466                 if (pte_present(*pte)) {
 467                         phys = pte_val(*pte) & PAGE_MASK;
 468                         set_fixmap(idx, phys);
 469                 }
 470         }
 471 }
 472
 473 static void __init __early_set_fixmap(enum fixed_addresses idx,
 474                                    unsigned long phys, pgprot_t flags)
 475 {
 476         unsigned long addr = __fix_to_virt(idx);
 477         pte_t *pte;
 478
 479         if (idx >= __end_of_fixed_addresses) {
 480                 BUG();
 481                 return;
 482         }
 483         pte = early_ioremap_pte(addr);
 484
 485         if (pgprot_val(flags))
 486                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 487         else
 488                 pte_clear(NULL, addr, pte);
 489         __flush_tlb_one(addr);
 490 }
 491
 492 static inline void __init early_set_fixmap(enum fixed_addresses idx,
 493                                         unsigned long phys)
 494 {
 495         if (after_paging_init)
 496                 set_fixmap(idx, phys);
 497         else
 498                 __early_set_fixmap(idx, phys, PAGE_KERNEL);
 499 }
 500
 501 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
 502 {
 503         if (after_paging_init)
 504                 clear_fixmap(idx);
 505         else
 506                 __early_set_fixmap(idx, 0, __pgprot(0));
 507 }
 508
 509
 510 int __initdata early_ioremap_nested;
 511
 512 static int __init check_early_ioremap_leak(void)
 513 {
 514         if (!early_ioremap_nested)
 515                 return 0;
 516
 517         printk(KERN_WARNING
 518                "Debug warning: early ioremap leak of %d areas detected.\n",
 519                early_ioremap_nested);
 520         printk(KERN_WARNING
 521                "please boot with early_ioremap_debug and report the dmesg.\n");
 522         WARN_ON(1);
 523
 524         return 1;
 525 }
 526 late_initcall(check_early_ioremap_leak);
 527
 528 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
 529 {
 530         unsigned long offset, last_addr;
 531         unsigned int nrpages, nesting;
 532         enum fixed_addresses idx0, idx;
 533
 534         WARN_ON(system_state != SYSTEM_BOOTING);
 535
 536         nesting = early_ioremap_nested;
 537         if (early_ioremap_debug) {
 538                 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
 539                        phys_addr, size, nesting);
 540                 dump_stack();
 541         }
 542
 543         /* Don't allow wraparound or zero size */
 544         last_addr = phys_addr + size - 1;
 545         if (!size || last_addr < phys_addr) {
 546                 WARN_ON(1);
 547                 return NULL;
 548         }
 549
 550         if (nesting >= FIX_BTMAPS_NESTING) {
 551                 WARN_ON(1);
 552                 return NULL;
 553         }
 554         early_ioremap_nested++;
 555         /*
 556          * Mappings have to be page-aligned
 557          */
 558         offset = phys_addr & ~PAGE_MASK;
 559         phys_addr &= PAGE_MASK;
 560         size = PAGE_ALIGN(last_addr) - phys_addr;
 561
 562         /*
 563          * Mappings have to fit in the FIX_BTMAP area.
 564          */
 565         nrpages = size >> PAGE_SHIFT;
 566         if (nrpages > NR_FIX_BTMAPS) {
 567                 WARN_ON(1);
 568                 return NULL;
 569         }
 570
 571         /*
 572          * Ok, go for it..
 573          */
 574         idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
 575         idx = idx0;
 576         while (nrpages > 0) {
 577                 early_set_fixmap(idx, phys_addr);
 578                 phys_addr += PAGE_SIZE;
 579                 --idx;
 580                 --nrpages;
 581         }
 582         if (early_ioremap_debug)
 583                 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
 584
 585         return (void *) (offset + fix_to_virt(idx0));
 586 }
 587
 588 void __init early_iounmap(void *addr, unsigned long size)
 589 {
 590         unsigned long virt_addr;
 591         unsigned long offset;
 592         unsigned int nrpages;
 593         enum fixed_addresses idx;
 594         int nesting;
 595
 596         nesting = --early_ioremap_nested;
 597         if (WARN_ON(nesting < 0))
 598                 return;
 599
 600         if (early_ioremap_debug) {
 601                 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
 602                        size, nesting);
 603                 dump_stack();
 604         }
 605
 606         virt_addr = (unsigned long)addr;
 607         if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
 608                 WARN_ON(1);
 609                 return;
 610         }
 611         offset = virt_addr & ~PAGE_MASK;
 612         nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
 613
 614         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
 615         while (nrpages > 0) {
 616                 early_clear_fixmap(idx);
 617                 --idx;
 618                 --nrpages;
 619         }
 620 }
 621
 622 void __this_fixmap_does_not_exist(void)
 623 {
 624         WARN_ON(1);
 625 }