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