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