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 #include <linux/mmiotrace.h>
  16
  17 #include <asm/cacheflush.h>
  18 #include <asm/e820.h>
  19 #include <asm/fixmap.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/tlbflush.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/pat.h>
  24
  25 #ifdef CONFIG_X86_64
  26
  27 static inline int phys_addr_valid(unsigned long addr)
  28 {
  29         return addr < (1UL << boot_cpu_data.x86_phys_bits);
  30 }
  31
  32 unsigned long __phys_addr(unsigned long x)
  33 {
  34         if (x >= __START_KERNEL_map) {
  35                 x -= __START_KERNEL_map;
  36                 VIRTUAL_BUG_ON(x >= KERNEL_IMAGE_SIZE);
  37                 x += phys_base;
  38         } else {
  39                 VIRTUAL_BUG_ON(x < PAGE_OFFSET);
  40                 x -= PAGE_OFFSET;
  41                 VIRTUAL_BUG_ON(system_state == SYSTEM_BOOTING ? x > MAXMEM :
  42                                         !phys_addr_valid(x));
  43         }
  44         return x;
  45 }
  46 EXPORT_SYMBOL(__phys_addr);
  47
  48 #else
  49
  50 static inline int phys_addr_valid(unsigned long addr)
  51 {
  52         return 1;
  53 }
  54
  55 #ifdef CONFIG_DEBUG_VIRTUAL
  56 unsigned long __phys_addr(unsigned long x)
  57 {
  58         /* VMALLOC_* aren't constants; not available at the boot time */
  59         VIRTUAL_BUG_ON(x < PAGE_OFFSET || (system_state != SYSTEM_BOOTING &&
  60                                         is_vmalloc_addr((void *)x)));
  61         return x - PAGE_OFFSET;
  62 }
  63 EXPORT_SYMBOL(__phys_addr);
  64 #endif
  65
  66 #endif
  67
  68 int page_is_ram(unsigned long pagenr)
  69 {
  70         resource_size_t addr, end;
  71         int i;
  72
  73         /*
  74          * A special case is the first 4Kb of memory;
  75          * This is a BIOS owned area, not kernel ram, but generally
  76          * not listed as such in the E820 table.
  77          */
  78         if (pagenr == 0)
  79                 return 0;
  80
  81         /*
  82          * Second special case: Some BIOSen report the PC BIOS
  83          * area (640->1Mb) as ram even though it is not.
  84          */
  85         if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
  86                     pagenr < (BIOS_END >> PAGE_SHIFT))
  87                 return 0;
  88
  89         for (i = 0; i < e820.nr_map; i++) {
  90                 /*
  91                  * Not usable memory:
  92                  */
  93                 if (e820.map[i].type != E820_RAM)
  94                         continue;
  95                 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
  96                 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
  97
  98
  99                 if ((pagenr >= addr) && (pagenr < end))
 100                         return 1;
 101         }
 102         return 0;
 103 }
 104
 105 int pagerange_is_ram(unsigned long start, unsigned long end)
 106 {
 107         int ram_page = 0, not_rampage = 0;
 108         unsigned long page_nr;
 109
 110         for (page_nr = (start >> PAGE_SHIFT); page_nr < (end >> PAGE_SHIFT);
 111              ++page_nr) {
 112                 if (page_is_ram(page_nr))
 113                         ram_page = 1;
 114                 else
 115                         not_rampage = 1;
 116
 117                 if (ram_page == not_rampage)
 118                         return -1;
 119         }
 120
 121         return ram_page;
 122 }
 123
 124 /*
 125  * Fix up the linear direct mapping of the kernel to avoid cache attribute
 126  * conflicts.
 127  */
 128 int ioremap_change_attr(unsigned long vaddr, unsigned long size,
 129                                unsigned long prot_val)
 130 {
 131         unsigned long nrpages = size >> PAGE_SHIFT;
 132         int err;
 133
 134         switch (prot_val) {
 135         case _PAGE_CACHE_UC:
 136         default:
 137                 err = _set_memory_uc(vaddr, nrpages);
 138                 break;
 139         case _PAGE_CACHE_WC:
 140                 err = _set_memory_wc(vaddr, nrpages);
 141                 break;
 142         case _PAGE_CACHE_WB:
 143                 err = _set_memory_wb(vaddr, nrpages);
 144                 break;
 145         }
 146
 147         return err;
 148 }
 149
 150 /*
 151  * Remap an arbitrary physical address space into the kernel virtual
 152  * address space. Needed when the kernel wants to access high addresses
 153  * directly.
 154  *
 155  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 156  * have to convert them into an offset in a page-aligned mapping, but the
 157  * caller shouldn't need to know that small detail.
 158  */
 159 static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 160                 unsigned long size, unsigned long prot_val, void *caller)
 161 {
 162         unsigned long pfn, offset, vaddr;
 163         resource_size_t last_addr;
 164         const resource_size_t unaligned_phys_addr = phys_addr;
 165         const unsigned long unaligned_size = size;
 166         struct vm_struct *area;
 167         unsigned long new_prot_val;
 168         pgprot_t prot;
 169         int retval;
 170         void __iomem *ret_addr;
 171
 172         /* Don't allow wraparound or zero size */
 173         last_addr = phys_addr + size - 1;
 174         if (!size || last_addr < phys_addr)
 175                 return NULL;
 176
 177         if (!phys_addr_valid(phys_addr)) {
 178                 printk(KERN_WARNING "ioremap: invalid physical address %llx\n",
 179                        (unsigned long long)phys_addr);
 180                 WARN_ON_ONCE(1);
 181                 return NULL;
 182         }
 183
 184         /*
 185          * Don't remap the low PCI/ISA area, it's always mapped..
 186          */
 187         if (is_ISA_range(phys_addr, last_addr))
 188                 return (__force void __iomem *)phys_to_virt(phys_addr);
 189
 190         /*
 191          * Don't allow anybody to remap normal RAM that we're using..
 192          */
 193         for (pfn = phys_addr >> PAGE_SHIFT;
 194                                 (pfn << PAGE_SHIFT) < (last_addr & PAGE_MASK);
 195                                 pfn++) {
 196
 197                 int is_ram = page_is_ram(pfn);
 198
 199                 if (is_ram && pfn_valid(pfn) && !PageReserved(pfn_to_page(pfn)))
 200                         return NULL;
 201                 WARN_ON_ONCE(is_ram);
 202         }
 203
 204         /*
 205          * Mappings have to be page-aligned
 206          */
 207         offset = phys_addr & ~PAGE_MASK;
 208         phys_addr &= PAGE_MASK;
 209         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 210
 211         retval = reserve_memtype(phys_addr, (u64)phys_addr + size,
 212                                                 prot_val, &new_prot_val);
 213         if (retval) {
 214                 pr_debug("Warning: reserve_memtype returned %d\n", retval);
 215                 return NULL;
 216         }
 217
 218         if (prot_val != new_prot_val) {
 219                 /*
 220                  * Do not fallback to certain memory types with certain
 221                  * requested type:
 222                  * - request is uc-, return cannot be write-back
 223                  * - request is uc-, return cannot be write-combine
 224                  * - request is write-combine, return cannot be write-back
 225                  */
 226                 if ((prot_val == _PAGE_CACHE_UC_MINUS &&
 227                      (new_prot_val == _PAGE_CACHE_WB ||
 228                       new_prot_val == _PAGE_CACHE_WC)) ||
 229                     (prot_val == _PAGE_CACHE_WC &&
 230                      new_prot_val == _PAGE_CACHE_WB)) {
 231                         pr_debug(
 232                 "ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n",
 233                                 (unsigned long long)phys_addr,
 234                                 (unsigned long long)(phys_addr + size),
 235                                 prot_val, new_prot_val);
 236                         free_memtype(phys_addr, phys_addr + size);
 237                         return NULL;
 238                 }
 239                 prot_val = new_prot_val;
 240         }
 241
 242         switch (prot_val) {
 243         case _PAGE_CACHE_UC:
 244         default:
 245                 prot = PAGE_KERNEL_IO_NOCACHE;
 246                 break;
 247         case _PAGE_CACHE_UC_MINUS:
 248                 prot = PAGE_KERNEL_IO_UC_MINUS;
 249                 break;
 250         case _PAGE_CACHE_WC:
 251                 prot = PAGE_KERNEL_IO_WC;
 252                 break;
 253         case _PAGE_CACHE_WB:
 254                 prot = PAGE_KERNEL_IO;
 255                 break;
 256         }
 257
 258         /*
 259          * Ok, go for it..
 260          */
 261         area = get_vm_area_caller(size, VM_IOREMAP, caller);
 262         if (!area)
 263                 return NULL;
 264         area->phys_addr = phys_addr;
 265         vaddr = (unsigned long) area->addr;
 266         if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
 267                 free_memtype(phys_addr, phys_addr + size);
 268                 free_vm_area(area);
 269                 return NULL;
 270         }
 271
 272         if (ioremap_change_attr(vaddr, size, prot_val) < 0) {
 273                 free_memtype(phys_addr, phys_addr + size);
 274                 vunmap(area->addr);
 275                 return NULL;
 276         }
 277
 278         ret_addr = (void __iomem *) (vaddr + offset);
 279         mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr);
 280
 281         return ret_addr;
 282 }
 283
 284 /**
 285  * ioremap_nocache     -   map bus memory into CPU space
 286  * @offset:    bus address of the memory
 287  * @size:      size of the resource to map
 288  *
 289  * ioremap_nocache performs a platform specific sequence of operations to
 290  * make bus memory CPU accessible via the readb/readw/readl/writeb/
 291  * writew/writel functions and the other mmio helpers. The returned
 292  * address is not guaranteed to be usable directly as a virtual
 293  * address.
 294  *
 295  * This version of ioremap ensures that the memory is marked uncachable
 296  * on the CPU as well as honouring existing caching rules from things like
 297  * the PCI bus. Note that there are other caches and buffers on many
 298  * busses. In particular driver authors should read up on PCI writes
 299  *
 300  * It's useful if some control registers are in such an area and
 301  * write combining or read caching is not desirable:
 302  *
 303  * Must be freed with iounmap.
 304  */
 305 void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
 306 {
 307         /*
 308          * Ideally, this should be:
 309          *      pat_enabled ? _PAGE_CACHE_UC : _PAGE_CACHE_UC_MINUS;
 310          *
 311          * Till we fix all X drivers to use ioremap_wc(), we will use
 312          * UC MINUS.
 313          */
 314         unsigned long val = _PAGE_CACHE_UC_MINUS;
 315
 316         return __ioremap_caller(phys_addr, size, val,
 317                                 __builtin_return_address(0));
 318 }
 319 EXPORT_SYMBOL(ioremap_nocache);
 320
 321 /**
 322  * ioremap_wc   -       map memory into CPU space write combined
 323  * @offset:     bus address of the memory
 324  * @size:       size of the resource to map
 325  *
 326  * This version of ioremap ensures that the memory is marked write combining.
 327  * Write combining allows faster writes to some hardware devices.
 328  *
 329  * Must be freed with iounmap.
 330  */
 331 void __iomem *ioremap_wc(unsigned long phys_addr, unsigned long size)
 332 {
 333         if (pat_enabled)
 334                 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WC,
 335                                         __builtin_return_address(0));
 336         else
 337                 return ioremap_nocache(phys_addr, size);
 338 }
 339 EXPORT_SYMBOL(ioremap_wc);
 340
 341 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
 342 {
 343         return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WB,
 344                                 __builtin_return_address(0));
 345 }
 346 EXPORT_SYMBOL(ioremap_cache);
 347
 348 static void __iomem *ioremap_default(resource_size_t phys_addr,
 349                                         unsigned long size)
 350 {
 351         unsigned long flags;
 352         void *ret;
 353         int err;
 354
 355         /*
 356          * - WB for WB-able memory and no other conflicting mappings
 357          * - UC_MINUS for non-WB-able memory with no other conflicting mappings
 358          * - Inherit from confliting mappings otherwise
 359          */
 360         err = reserve_memtype(phys_addr, phys_addr + size, -1, &flags);
 361         if (err < 0)
 362                 return NULL;
 363
 364         ret = (void *) __ioremap_caller(phys_addr, size, flags,
 365                                         __builtin_return_address(0));
 366
 367         free_memtype(phys_addr, phys_addr + size);
 368         return (void __iomem *)ret;
 369 }
 370
 371 void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size,
 372                                 unsigned long prot_val)
 373 {
 374         return __ioremap_caller(phys_addr, size, (prot_val & _PAGE_CACHE_MASK),
 375                                 __builtin_return_address(0));
 376 }
 377 EXPORT_SYMBOL(ioremap_prot);
 378
 379 /**
 380  * iounmap - Free a IO remapping
 381  * @addr: virtual address from ioremap_*
 382  *
 383  * Caller must ensure there is only one unmapping for the same pointer.
 384  */
 385 void iounmap(volatile void __iomem *addr)
 386 {
 387         struct vm_struct *p, *o;
 388
 389         if ((void __force *)addr <= high_memory)
 390                 return;
 391
 392         /*
 393          * __ioremap special-cases the PCI/ISA range by not instantiating a
 394          * vm_area and by simply returning an address into the kernel mapping
 395          * of ISA space.   So handle that here.
 396          */
 397         if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) &&
 398             (void __force *)addr < phys_to_virt(ISA_END_ADDRESS))
 399                 return;
 400
 401         addr = (volatile void __iomem *)
 402                 (PAGE_MASK & (unsigned long __force)addr);
 403
 404         mmiotrace_iounmap(addr);
 405
 406         /* Use the vm area unlocked, assuming the caller
 407            ensures there isn't another iounmap for the same address
 408            in parallel. Reuse of the virtual address is prevented by
 409            leaving it in the global lists until we're done with it.
 410            cpa takes care of the direct mappings. */
 411         read_lock(&vmlist_lock);
 412         for (p = vmlist; p; p = p->next) {
 413                 if (p->addr == (void __force *)addr)
 414                         break;
 415         }
 416         read_unlock(&vmlist_lock);
 417
 418         if (!p) {
 419                 printk(KERN_ERR "iounmap: bad address %p\n", addr);
 420                 dump_stack();
 421                 return;
 422         }
 423
 424         free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p));
 425
 426         /* Finally remove it */
 427         o = remove_vm_area((void __force *)addr);
 428         BUG_ON(p != o || o == NULL);
 429         kfree(p);
 430 }
 431 EXPORT_SYMBOL(iounmap);
 432
 433 /*
 434  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
 435  * access
 436  */
 437 void *xlate_dev_mem_ptr(unsigned long phys)
 438 {
 439         void *addr;
 440         unsigned long start = phys & PAGE_MASK;
 441
 442         /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */
 443         if (page_is_ram(start >> PAGE_SHIFT))
 444                 return __va(phys);
 445
 446         addr = (void __force *)ioremap_default(start, PAGE_SIZE);
 447         if (addr)
 448                 addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK));
 449
 450         return addr;
 451 }
 452
 453 void unxlate_dev_mem_ptr(unsigned long phys, void *addr)
 454 {
 455         if (page_is_ram(phys >> PAGE_SHIFT))
 456                 return;
 457
 458         iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
 459         return;
 460 }
 461
 462 static int __initdata early_ioremap_debug;
 463
 464 static int __init early_ioremap_debug_setup(char *str)
 465 {
 466         early_ioremap_debug = 1;
 467
 468         return 0;
 469 }
 470 early_param("early_ioremap_debug", early_ioremap_debug_setup);
 471
 472 static __initdata int after_paging_init;
 473 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;
 474
 475 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 476 {
 477         /* Don't assume we're using swapper_pg_dir at this point */
 478         pgd_t *base = __va(read_cr3());
 479         pgd_t *pgd = &base[pgd_index(addr)];
 480         pud_t *pud = pud_offset(pgd, addr);
 481         pmd_t *pmd = pmd_offset(pud, addr);
 482
 483         return pmd;
 484 }
 485
 486 static inline pte_t * __init early_ioremap_pte(unsigned long addr)
 487 {
 488         return &bm_pte[pte_index(addr)];
 489 }
 490
 491 void __init early_ioremap_init(void)
 492 {
 493         pmd_t *pmd;
 494
 495         if (early_ioremap_debug)
 496                 printk(KERN_INFO "early_ioremap_init()\n");
 497
 498         pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
 499         memset(bm_pte, 0, sizeof(bm_pte));
 500         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 501
 502         /*
 503          * The boot-ioremap range spans multiple pmds, for which
 504          * we are not prepared:
 505          */
 506         if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 507                 WARN_ON(1);
 508                 printk(KERN_WARNING "pmd %p != %p\n",
 509                        pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
 510                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 511                         fix_to_virt(FIX_BTMAP_BEGIN));
 512                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 513                         fix_to_virt(FIX_BTMAP_END));
 514
 515                 printk(KERN_WARNING "FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 516                 printk(KERN_WARNING "FIX_BTMAP_BEGIN:     %d\n",
 517                        FIX_BTMAP_BEGIN);
 518         }
 519 }
 520
 521 void __init early_ioremap_clear(void)
 522 {
 523         pmd_t *pmd;
 524
 525         if (early_ioremap_debug)
 526                 printk(KERN_INFO "early_ioremap_clear()\n");
 527
 528         pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
 529         pmd_clear(pmd);
 530         paravirt_release_pte(__pa(bm_pte) >> PAGE_SHIFT);
 531         __flush_tlb_all();
 532 }
 533
 534 void __init early_ioremap_reset(void)
 535 {
 536         enum fixed_addresses idx;
 537         unsigned long addr, phys;
 538         pte_t *pte;
 539
 540         after_paging_init = 1;
 541         for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
 542                 addr = fix_to_virt(idx);
 543                 pte = early_ioremap_pte(addr);
 544                 if (pte_present(*pte)) {
 545                         phys = pte_val(*pte) & PAGE_MASK;
 546                         set_fixmap(idx, phys);
 547                 }
 548         }
 549 }
 550
 551 static void __init __early_set_fixmap(enum fixed_addresses idx,
 552                                    unsigned long phys, pgprot_t flags)
 553 {
 554         unsigned long addr = __fix_to_virt(idx);
 555         pte_t *pte;
 556
 557         if (idx >= __end_of_fixed_addresses) {
 558                 BUG();
 559                 return;
 560         }
 561         pte = early_ioremap_pte(addr);
 562
 563         if (pgprot_val(flags))
 564                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 565         else
 566                 pte_clear(&init_mm, addr, pte);
 567         __flush_tlb_one(addr);
 568 }
 569
 570 static inline void __init early_set_fixmap(enum fixed_addresses idx,
 571                                            unsigned long phys, pgprot_t prot)
 572 {
 573         if (after_paging_init)
 574                 __set_fixmap(idx, phys, prot);
 575         else
 576                 __early_set_fixmap(idx, phys, prot);
 577 }
 578
 579 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
 580 {
 581         if (after_paging_init)
 582                 clear_fixmap(idx);
 583         else
 584                 __early_set_fixmap(idx, 0, __pgprot(0));
 585 }
 586
 587
 588 static int __initdata early_ioremap_nested;
 589
 590 static int __init check_early_ioremap_leak(void)
 591 {
 592         if (!early_ioremap_nested)
 593                 return 0;
 594         WARN(1, KERN_WARNING
 595                "Debug warning: early ioremap leak of %d areas detected.\n",
 596                 early_ioremap_nested);
 597         printk(KERN_WARNING
 598                 "please boot with early_ioremap_debug and report the dmesg.\n");
 599
 600         return 1;
 601 }
 602 late_initcall(check_early_ioremap_leak);
 603
 604 static void __init *__early_ioremap(unsigned long phys_addr, unsigned long size, pgprot_t prot)
 605 {
 606         unsigned long offset, last_addr;
 607         unsigned int nrpages, nesting;
 608         enum fixed_addresses idx0, idx;
 609
 610         WARN_ON(system_state != SYSTEM_BOOTING);
 611
 612         nesting = early_ioremap_nested;
 613         if (early_ioremap_debug) {
 614                 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
 615                        phys_addr, size, nesting);
 616                 dump_stack();
 617         }
 618
 619         /* Don't allow wraparound or zero size */
 620         last_addr = phys_addr + size - 1;
 621         if (!size || last_addr < phys_addr) {
 622                 WARN_ON(1);
 623                 return NULL;
 624         }
 625
 626         if (nesting >= FIX_BTMAPS_NESTING) {
 627                 WARN_ON(1);
 628                 return NULL;
 629         }
 630         early_ioremap_nested++;
 631         /*
 632          * Mappings have to be page-aligned
 633          */
 634         offset = phys_addr & ~PAGE_MASK;
 635         phys_addr &= PAGE_MASK;
 636         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 637
 638         /*
 639          * Mappings have to fit in the FIX_BTMAP area.
 640          */
 641         nrpages = size >> PAGE_SHIFT;
 642         if (nrpages > NR_FIX_BTMAPS) {
 643                 WARN_ON(1);
 644                 return NULL;
 645         }
 646
 647         /*
 648          * Ok, go for it..
 649          */
 650         idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
 651         idx = idx0;
 652         while (nrpages > 0) {
 653                 early_set_fixmap(idx, phys_addr, prot);
 654                 phys_addr += PAGE_SIZE;
 655                 --idx;
 656                 --nrpages;
 657         }
 658         if (early_ioremap_debug)
 659                 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
 660
 661         return (void *) (offset + fix_to_virt(idx0));
 662 }
 663
 664 /* Remap an IO device */
 665 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
 666 {
 667         return __early_ioremap(phys_addr, size, PAGE_KERNEL_IO);
 668 }
 669
 670 /* Remap memory */
 671 void __init *early_memremap(unsigned long phys_addr, unsigned long size)
 672 {
 673         return __early_ioremap(phys_addr, size, PAGE_KERNEL);
 674 }
 675
 676 void __init early_iounmap(void *addr, unsigned long size)
 677 {
 678         unsigned long virt_addr;
 679         unsigned long offset;
 680         unsigned int nrpages;
 681         enum fixed_addresses idx;
 682         int nesting;
 683
 684         nesting = --early_ioremap_nested;
 685         if (WARN_ON(nesting < 0))
 686                 return;
 687
 688         if (early_ioremap_debug) {
 689                 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
 690                        size, nesting);
 691                 dump_stack();
 692         }
 693
 694         virt_addr = (unsigned long)addr;
 695         if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
 696                 WARN_ON(1);
 697                 return;
 698         }
 699         offset = virt_addr & ~PAGE_MASK;
 700         nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
 701
 702         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
 703         while (nrpages > 0) {
 704                 early_clear_fixmap(idx);
 705                 --idx;
 706                 --nrpages;
 707         }
 708 }
 709
 710 void __this_fixmap_does_not_exist(void)
 711 {
 712         WARN_ON(1);
 713 }