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
  23 enum ioremap_mode {
  24         IOR_MODE_UNCACHED,
  25         IOR_MODE_CACHED,
  26 };
  27
  28 #ifdef CONFIG_X86_64
  29
  30 unsigned long __phys_addr(unsigned long x)
  31 {
  32         if (x >= __START_KERNEL_map)
  33                 return x - __START_KERNEL_map + phys_base;
  34         return x - PAGE_OFFSET;
  35 }
  36 EXPORT_SYMBOL(__phys_addr);
  37
  38 #endif
  39
  40 int page_is_ram(unsigned long pagenr)
  41 {
  42         unsigned long addr, end;
  43         int i;
  44
  45         for (i = 0; i < e820.nr_map; i++) {
  46                 /*
  47                  * Not usable memory:
  48                  */
  49                 if (e820.map[i].type != E820_RAM)
  50                         continue;
  51                 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
  52                 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
  53
  54                 /*
  55                  * Sanity check: Some BIOSen report areas as RAM that
  56                  * are not. Notably the 640->1Mb area, which is the
  57                  * PCI BIOS area.
  58                  */
  59                 if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
  60                     end < (BIOS_END >> PAGE_SHIFT))
  61                         continue;
  62
  63                 if ((pagenr >= addr) && (pagenr < end))
  64                         return 1;
  65         }
  66         return 0;
  67 }
  68
  69 /*
  70  * Fix up the linear direct mapping of the kernel to avoid cache attribute
  71  * conflicts.
  72  */
  73 static int ioremap_change_attr(unsigned long vaddr, unsigned long size,
  74                                enum ioremap_mode mode)
  75 {
  76         unsigned long nrpages = size >> PAGE_SHIFT;
  77         int err;
  78
  79         switch (mode) {
  80         case IOR_MODE_UNCACHED:
  81         default:
  82                 err = set_memory_uc(vaddr, nrpages);
  83                 break;
  84         case IOR_MODE_CACHED:
  85                 err = set_memory_wb(vaddr, nrpages);
  86                 break;
  87         }
  88
  89         return err;
  90 }
  91
  92 /*
  93  * Remap an arbitrary physical address space into the kernel virtual
  94  * address space. Needed when the kernel wants to access high addresses
  95  * directly.
  96  *
  97  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  98  * have to convert them into an offset in a page-aligned mapping, but the
  99  * caller shouldn't need to know that small detail.
 100  */
 101 static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
 102                                enum ioremap_mode mode)
 103 {
 104         unsigned long pfn, offset, last_addr, vaddr;
 105         struct vm_struct *area;
 106         pgprot_t prot;
 107
 108         /* Don't allow wraparound or zero size */
 109         last_addr = phys_addr + size - 1;
 110         if (!size || last_addr < phys_addr)
 111                 return NULL;
 112
 113         /*
 114          * Don't remap the low PCI/ISA area, it's always mapped..
 115          */
 116         if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
 117                 return (__force void __iomem *)phys_to_virt(phys_addr);
 118
 119         /*
 120          * Don't allow anybody to remap normal RAM that we're using..
 121          */
 122         for (pfn = phys_addr >> PAGE_SHIFT; pfn < max_pfn_mapped &&
 123              (pfn << PAGE_SHIFT) < last_addr; pfn++) {
 124                 if (page_is_ram(pfn) && pfn_valid(pfn) &&
 125                     !PageReserved(pfn_to_page(pfn)))
 126                         return NULL;
 127         }
 128
 129         switch (mode) {
 130         case IOR_MODE_UNCACHED:
 131         default:
 132                 prot = PAGE_KERNEL_NOCACHE;
 133                 break;
 134         case IOR_MODE_CACHED:
 135                 prot = PAGE_KERNEL;
 136                 break;
 137         }
 138
 139         /*
 140          * Mappings have to be page-aligned
 141          */
 142         offset = phys_addr & ~PAGE_MASK;
 143         phys_addr &= PAGE_MASK;
 144         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 145
 146         /*
 147          * Ok, go for it..
 148          */
 149         area = get_vm_area(size, VM_IOREMAP);
 150         if (!area)
 151                 return NULL;
 152         area->phys_addr = phys_addr;
 153         vaddr = (unsigned long) area->addr;
 154         if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
 155                 remove_vm_area((void *)(vaddr & PAGE_MASK));
 156                 return NULL;
 157         }
 158
 159         if (ioremap_change_attr(vaddr, size, mode) < 0) {
 160                 vunmap(area->addr);
 161                 return NULL;
 162         }
 163
 164         return (void __iomem *) (vaddr + offset);
 165 }
 166
 167 /**
 168  * ioremap_nocache     -   map bus memory into CPU space
 169  * @offset:    bus address of the memory
 170  * @size:      size of the resource to map
 171  *
 172  * ioremap_nocache performs a platform specific sequence of operations to
 173  * make bus memory CPU accessible via the readb/readw/readl/writeb/
 174  * writew/writel functions and the other mmio helpers. The returned
 175  * address is not guaranteed to be usable directly as a virtual
 176  * address.
 177  *
 178  * This version of ioremap ensures that the memory is marked uncachable
 179  * on the CPU as well as honouring existing caching rules from things like
 180  * the PCI bus. Note that there are other caches and buffers on many
 181  * busses. In particular driver authors should read up on PCI writes
 182  *
 183  * It's useful if some control registers are in such an area and
 184  * write combining or read caching is not desirable:
 185  *
 186  * Must be freed with iounmap.
 187  */
 188 void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
 189 {
 190         return __ioremap(phys_addr, size, IOR_MODE_UNCACHED);
 191 }
 192 EXPORT_SYMBOL(ioremap_nocache);
 193
 194 void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size)
 195 {
 196         return __ioremap(phys_addr, size, IOR_MODE_CACHED);
 197 }
 198 EXPORT_SYMBOL(ioremap_cache);
 199
 200 /**
 201  * iounmap - Free a IO remapping
 202  * @addr: virtual address from ioremap_*
 203  *
 204  * Caller must ensure there is only one unmapping for the same pointer.
 205  */
 206 void iounmap(volatile void __iomem *addr)
 207 {
 208         struct vm_struct *p, *o;
 209
 210         if ((void __force *)addr <= high_memory)
 211                 return;
 212
 213         /*
 214          * __ioremap special-cases the PCI/ISA range by not instantiating a
 215          * vm_area and by simply returning an address into the kernel mapping
 216          * of ISA space.   So handle that here.
 217          */
 218         if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
 219             addr < phys_to_virt(ISA_END_ADDRESS))
 220                 return;
 221
 222         addr = (volatile void __iomem *)
 223                 (PAGE_MASK & (unsigned long __force)addr);
 224
 225         /* Use the vm area unlocked, assuming the caller
 226            ensures there isn't another iounmap for the same address
 227            in parallel. Reuse of the virtual address is prevented by
 228            leaving it in the global lists until we're done with it.
 229            cpa takes care of the direct mappings. */
 230         read_lock(&vmlist_lock);
 231         for (p = vmlist; p; p = p->next) {
 232                 if (p->addr == addr)
 233                         break;
 234         }
 235         read_unlock(&vmlist_lock);
 236
 237         if (!p) {
 238                 printk(KERN_ERR "iounmap: bad address %p\n", addr);
 239                 dump_stack();
 240                 return;
 241         }
 242
 243         /* Finally remove it */
 244         o = remove_vm_area((void *)addr);
 245         BUG_ON(p != o || o == NULL);
 246         kfree(p);
 247 }
 248 EXPORT_SYMBOL(iounmap);
 249
 250 #ifdef CONFIG_X86_32
 251
 252 int __initdata early_ioremap_debug;
 253
 254 static int __init early_ioremap_debug_setup(char *str)
 255 {
 256         early_ioremap_debug = 1;
 257
 258         return 0;
 259 }
 260 early_param("early_ioremap_debug", early_ioremap_debug_setup);
 261
 262 static __initdata int after_paging_init;
 263 static __initdata unsigned long bm_pte[1024]
 264                                 __attribute__((aligned(PAGE_SIZE)));
 265
 266 static inline unsigned long * __init early_ioremap_pgd(unsigned long addr)
 267 {
 268         return (unsigned long *)swapper_pg_dir + ((addr >> 22) & 1023);
 269 }
 270
 271 static inline unsigned long * __init early_ioremap_pte(unsigned long addr)
 272 {
 273         return bm_pte + ((addr >> PAGE_SHIFT) & 1023);
 274 }
 275
 276 void __init early_ioremap_init(void)
 277 {
 278         unsigned long *pgd;
 279
 280         if (early_ioremap_debug)
 281                 printk(KERN_INFO "early_ioremap_init()\n");
 282
 283         pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
 284         *pgd = __pa(bm_pte) | _PAGE_TABLE;
 285         memset(bm_pte, 0, sizeof(bm_pte));
 286         /*
 287          * The boot-ioremap range spans multiple pgds, for which
 288          * we are not prepared:
 289          */
 290         if (pgd != early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))) {
 291                 WARN_ON(1);
 292                 printk(KERN_WARNING "pgd %p != %p\n",
 293                        pgd, early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END)));
 294                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 295                        fix_to_virt(FIX_BTMAP_BEGIN));
 296                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 297                        fix_to_virt(FIX_BTMAP_END));
 298
 299                 printk(KERN_WARNING "FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 300                 printk(KERN_WARNING "FIX_BTMAP_BEGIN:     %d\n",
 301                        FIX_BTMAP_BEGIN);
 302         }
 303 }
 304
 305 void __init early_ioremap_clear(void)
 306 {
 307         unsigned long *pgd;
 308
 309         if (early_ioremap_debug)
 310                 printk(KERN_INFO "early_ioremap_clear()\n");
 311
 312         pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
 313         *pgd = 0;
 314         paravirt_release_pt(__pa(pgd) >> PAGE_SHIFT);
 315         __flush_tlb_all();
 316 }
 317
 318 void __init early_ioremap_reset(void)
 319 {
 320         enum fixed_addresses idx;
 321         unsigned long *pte, phys, addr;
 322
 323         after_paging_init = 1;
 324         for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
 325                 addr = fix_to_virt(idx);
 326                 pte = early_ioremap_pte(addr);
 327                 if (*pte & _PAGE_PRESENT) {
 328                         phys = *pte & PAGE_MASK;
 329                         set_fixmap(idx, phys);
 330                 }
 331         }
 332 }
 333
 334 static void __init __early_set_fixmap(enum fixed_addresses idx,
 335                                    unsigned long phys, pgprot_t flags)
 336 {
 337         unsigned long *pte, addr = __fix_to_virt(idx);
 338
 339         if (idx >= __end_of_fixed_addresses) {
 340                 BUG();
 341                 return;
 342         }
 343         pte = early_ioremap_pte(addr);
 344         if (pgprot_val(flags))
 345                 *pte = (phys & PAGE_MASK) | pgprot_val(flags);
 346         else
 347                 *pte = 0;
 348         __flush_tlb_one(addr);
 349 }
 350
 351 static inline void __init early_set_fixmap(enum fixed_addresses idx,
 352                                         unsigned long phys)
 353 {
 354         if (after_paging_init)
 355                 set_fixmap(idx, phys);
 356         else
 357                 __early_set_fixmap(idx, phys, PAGE_KERNEL);
 358 }
 359
 360 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
 361 {
 362         if (after_paging_init)
 363                 clear_fixmap(idx);
 364         else
 365                 __early_set_fixmap(idx, 0, __pgprot(0));
 366 }
 367
 368
 369 int __initdata early_ioremap_nested;
 370
 371 static int __init check_early_ioremap_leak(void)
 372 {
 373         if (!early_ioremap_nested)
 374                 return 0;
 375
 376         printk(KERN_WARNING
 377                "Debug warning: early ioremap leak of %d areas detected.\n",
 378                early_ioremap_nested);
 379         printk(KERN_WARNING
 380                "please boot with early_ioremap_debug and report the dmesg.\n");
 381         WARN_ON(1);
 382
 383         return 1;
 384 }
 385 late_initcall(check_early_ioremap_leak);
 386
 387 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
 388 {
 389         unsigned long offset, last_addr;
 390         unsigned int nrpages, nesting;
 391         enum fixed_addresses idx0, idx;
 392
 393         WARN_ON(system_state != SYSTEM_BOOTING);
 394
 395         nesting = early_ioremap_nested;
 396         if (early_ioremap_debug) {
 397                 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
 398                        phys_addr, size, nesting);
 399                 dump_stack();
 400         }
 401
 402         /* Don't allow wraparound or zero size */
 403         last_addr = phys_addr + size - 1;
 404         if (!size || last_addr < phys_addr) {
 405                 WARN_ON(1);
 406                 return NULL;
 407         }
 408
 409         if (nesting >= FIX_BTMAPS_NESTING) {
 410                 WARN_ON(1);
 411                 return NULL;
 412         }
 413         early_ioremap_nested++;
 414         /*
 415          * Mappings have to be page-aligned
 416          */
 417         offset = phys_addr & ~PAGE_MASK;
 418         phys_addr &= PAGE_MASK;
 419         size = PAGE_ALIGN(last_addr) - phys_addr;
 420
 421         /*
 422          * Mappings have to fit in the FIX_BTMAP area.
 423          */
 424         nrpages = size >> PAGE_SHIFT;
 425         if (nrpages > NR_FIX_BTMAPS) {
 426                 WARN_ON(1);
 427                 return NULL;
 428         }
 429
 430         /*
 431          * Ok, go for it..
 432          */
 433         idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
 434         idx = idx0;
 435         while (nrpages > 0) {
 436                 early_set_fixmap(idx, phys_addr);
 437                 phys_addr += PAGE_SIZE;
 438                 --idx;
 439                 --nrpages;
 440         }
 441         if (early_ioremap_debug)
 442                 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
 443
 444         return (void *) (offset + fix_to_virt(idx0));
 445 }
 446
 447 void __init early_iounmap(void *addr, unsigned long size)
 448 {
 449         unsigned long virt_addr;
 450         unsigned long offset;
 451         unsigned int nrpages;
 452         enum fixed_addresses idx;
 453         unsigned int nesting;
 454
 455         nesting = --early_ioremap_nested;
 456         WARN_ON(nesting < 0);
 457
 458         if (early_ioremap_debug) {
 459                 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
 460                        size, nesting);
 461                 dump_stack();
 462         }
 463
 464         virt_addr = (unsigned long)addr;
 465         if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
 466                 WARN_ON(1);
 467                 return;
 468         }
 469         offset = virt_addr & ~PAGE_MASK;
 470         nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
 471
 472         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
 473         while (nrpages > 0) {
 474                 early_clear_fixmap(idx);
 475                 --idx;
 476                 --nrpages;
 477         }
 478 }
 479
 480 void __this_fixmap_does_not_exist(void)
 481 {
 482         WARN_ON(1);
 483 }
 484
 485 #endif /* CONFIG_X86_32 */