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/slab.h> 13 #include <linux/vmalloc.h> 14 #include <linux/mmiotrace.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 #include "physaddr.h" 25 26 /* 27 * Fix up the linear direct mapping of the kernel to avoid cache attribute 28 * conflicts. 29 */ 30 int ioremap_change_attr(unsigned long vaddr, unsigned long size, 31 enum page_cache_mode pcm) 32 { 33 unsigned long nrpages = size >> PAGE_SHIFT; 34 int err; 35 36 switch (pcm) { 37 case _PAGE_CACHE_MODE_UC: 38 default: 39 err = _set_memory_uc(vaddr, nrpages); 40 break; 41 case _PAGE_CACHE_MODE_WC: 42 err = _set_memory_wc(vaddr, nrpages); 43 break; 44 case _PAGE_CACHE_MODE_WT: 45 err = _set_memory_wt(vaddr, nrpages); 46 break; 47 case _PAGE_CACHE_MODE_WB: 48 err = _set_memory_wb(vaddr, nrpages); 49 break; 50 } 51 52 return err; 53 } 54 55 static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages, 56 void *arg) 57 { 58 unsigned long i; 59 60 for (i = 0; i < nr_pages; ++i) 61 if (pfn_valid(start_pfn + i) && 62 !PageReserved(pfn_to_page(start_pfn + i))) 63 return 1; 64 65 return 0; 66 } 67 68 /* 69 * Remap an arbitrary physical address space into the kernel virtual 70 * address space. It transparently creates kernel huge I/O mapping when 71 * the physical address is aligned by a huge page size (1GB or 2MB) and 72 * the requested size is at least the huge page size. 73 * 74 * NOTE: MTRRs can override PAT memory types with a 4KB granularity. 75 * Therefore, the mapping code falls back to use a smaller page toward 4KB 76 * when a mapping range is covered by non-WB type of MTRRs. 77 * 78 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 79 * have to convert them into an offset in a page-aligned mapping, but the 80 * caller shouldn't need to know that small detail. 81 */ 82 static void __iomem *__ioremap_caller(resource_size_t phys_addr, 83 unsigned long size, enum page_cache_mode pcm, void *caller) 84 { 85 unsigned long offset, vaddr; 86 resource_size_t pfn, last_pfn, last_addr; 87 const resource_size_t unaligned_phys_addr = phys_addr; 88 const unsigned long unaligned_size = size; 89 struct vm_struct *area; 90 enum page_cache_mode new_pcm; 91 pgprot_t prot; 92 int retval; 93 void __iomem *ret_addr; 94 95 /* Don't allow wraparound or zero size */ 96 last_addr = phys_addr + size - 1; 97 if (!size || last_addr < phys_addr) 98 return NULL; 99 100 if (!phys_addr_valid(phys_addr)) { 101 printk(KERN_WARNING "ioremap: invalid physical address %llx\n", 102 (unsigned long long)phys_addr); 103 WARN_ON_ONCE(1); 104 return NULL; 105 } 106 107 /* 108 * Don't remap the low PCI/ISA area, it's always mapped.. 109 */ 110 if (is_ISA_range(phys_addr, last_addr)) 111 return (__force void __iomem *)phys_to_virt(phys_addr); 112 113 /* 114 * Don't allow anybody to remap normal RAM that we're using.. 115 */ 116 pfn = phys_addr >> PAGE_SHIFT; 117 last_pfn = last_addr >> PAGE_SHIFT; 118 if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL, 119 __ioremap_check_ram) == 1) { 120 WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n", 121 &phys_addr, &last_addr); 122 return NULL; 123 } 124 125 /* 126 * Mappings have to be page-aligned 127 */ 128 offset = phys_addr & ~PAGE_MASK; 129 phys_addr &= PHYSICAL_PAGE_MASK; 130 size = PAGE_ALIGN(last_addr+1) - phys_addr; 131 132 retval = reserve_memtype(phys_addr, (u64)phys_addr + size, 133 pcm, &new_pcm); 134 if (retval) { 135 printk(KERN_ERR "ioremap reserve_memtype failed %d\n", retval); 136 return NULL; 137 } 138 139 if (pcm != new_pcm) { 140 if (!is_new_memtype_allowed(phys_addr, size, pcm, new_pcm)) { 141 printk(KERN_ERR 142 "ioremap error for 0x%llx-0x%llx, requested 0x%x, got 0x%x\n", 143 (unsigned long long)phys_addr, 144 (unsigned long long)(phys_addr + size), 145 pcm, new_pcm); 146 goto err_free_memtype; 147 } 148 pcm = new_pcm; 149 } 150 151 prot = PAGE_KERNEL_IO; 152 switch (pcm) { 153 case _PAGE_CACHE_MODE_UC: 154 default: 155 prot = __pgprot(pgprot_val(prot) | 156 cachemode2protval(_PAGE_CACHE_MODE_UC)); 157 break; 158 case _PAGE_CACHE_MODE_UC_MINUS: 159 prot = __pgprot(pgprot_val(prot) | 160 cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS)); 161 break; 162 case _PAGE_CACHE_MODE_WC: 163 prot = __pgprot(pgprot_val(prot) | 164 cachemode2protval(_PAGE_CACHE_MODE_WC)); 165 break; 166 case _PAGE_CACHE_MODE_WT: 167 prot = __pgprot(pgprot_val(prot) | 168 cachemode2protval(_PAGE_CACHE_MODE_WT)); 169 break; 170 case _PAGE_CACHE_MODE_WB: 171 break; 172 } 173 174 /* 175 * Ok, go for it.. 176 */ 177 area = get_vm_area_caller(size, VM_IOREMAP, caller); 178 if (!area) 179 goto err_free_memtype; 180 area->phys_addr = phys_addr; 181 vaddr = (unsigned long) area->addr; 182 183 if (kernel_map_sync_memtype(phys_addr, size, pcm)) 184 goto err_free_area; 185 186 if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) 187 goto err_free_area; 188 189 ret_addr = (void __iomem *) (vaddr + offset); 190 mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr); 191 192 /* 193 * Check if the request spans more than any BAR in the iomem resource 194 * tree. 195 */ 196 if (iomem_map_sanity_check(unaligned_phys_addr, unaligned_size)) 197 pr_warn("caller %pS mapping multiple BARs\n", caller); 198 199 return ret_addr; 200 err_free_area: 201 free_vm_area(area); 202 err_free_memtype: 203 free_memtype(phys_addr, phys_addr + size); 204 return NULL; 205 } 206 207 /** 208 * ioremap_nocache - map bus memory into CPU space 209 * @phys_addr: bus address of the memory 210 * @size: size of the resource to map 211 * 212 * ioremap_nocache performs a platform specific sequence of operations to 213 * make bus memory CPU accessible via the readb/readw/readl/writeb/ 214 * writew/writel functions and the other mmio helpers. The returned 215 * address is not guaranteed to be usable directly as a virtual 216 * address. 217 * 218 * This version of ioremap ensures that the memory is marked uncachable 219 * on the CPU as well as honouring existing caching rules from things like 220 * the PCI bus. Note that there are other caches and buffers on many 221 * busses. In particular driver authors should read up on PCI writes 222 * 223 * It's useful if some control registers are in such an area and 224 * write combining or read caching is not desirable: 225 * 226 * Must be freed with iounmap. 227 */ 228 void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size) 229 { 230 /* 231 * Ideally, this should be: 232 * pat_enabled() ? _PAGE_CACHE_MODE_UC : _PAGE_CACHE_MODE_UC_MINUS; 233 * 234 * Till we fix all X drivers to use ioremap_wc(), we will use 235 * UC MINUS. Drivers that are certain they need or can already 236 * be converted over to strong UC can use ioremap_uc(). 237 */ 238 enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC_MINUS; 239 240 return __ioremap_caller(phys_addr, size, pcm, 241 __builtin_return_address(0)); 242 } 243 EXPORT_SYMBOL(ioremap_nocache); 244 245 /** 246 * ioremap_uc - map bus memory into CPU space as strongly uncachable 247 * @phys_addr: bus address of the memory 248 * @size: size of the resource to map 249 * 250 * ioremap_uc performs a platform specific sequence of operations to 251 * make bus memory CPU accessible via the readb/readw/readl/writeb/ 252 * writew/writel functions and the other mmio helpers. The returned 253 * address is not guaranteed to be usable directly as a virtual 254 * address. 255 * 256 * This version of ioremap ensures that the memory is marked with a strong 257 * preference as completely uncachable on the CPU when possible. For non-PAT 258 * systems this ends up setting page-attribute flags PCD=1, PWT=1. For PAT 259 * systems this will set the PAT entry for the pages as strong UC. This call 260 * will honor existing caching rules from things like the PCI bus. Note that 261 * there are other caches and buffers on many busses. In particular driver 262 * authors should read up on PCI writes. 263 * 264 * It's useful if some control registers are in such an area and 265 * write combining or read caching is not desirable: 266 * 267 * Must be freed with iounmap. 268 */ 269 void __iomem *ioremap_uc(resource_size_t phys_addr, unsigned long size) 270 { 271 enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC; 272 273 return __ioremap_caller(phys_addr, size, pcm, 274 __builtin_return_address(0)); 275 } 276 EXPORT_SYMBOL_GPL(ioremap_uc); 277 278 /** 279 * ioremap_wc - map memory into CPU space write combined 280 * @phys_addr: bus address of the memory 281 * @size: size of the resource to map 282 * 283 * This version of ioremap ensures that the memory is marked write combining. 284 * Write combining allows faster writes to some hardware devices. 285 * 286 * Must be freed with iounmap. 287 */ 288 void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size) 289 { 290 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC, 291 __builtin_return_address(0)); 292 } 293 EXPORT_SYMBOL(ioremap_wc); 294 295 /** 296 * ioremap_wt - map memory into CPU space write through 297 * @phys_addr: bus address of the memory 298 * @size: size of the resource to map 299 * 300 * This version of ioremap ensures that the memory is marked write through. 301 * Write through stores data into memory while keeping the cache up-to-date. 302 * 303 * Must be freed with iounmap. 304 */ 305 void __iomem *ioremap_wt(resource_size_t phys_addr, unsigned long size) 306 { 307 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WT, 308 __builtin_return_address(0)); 309 } 310 EXPORT_SYMBOL(ioremap_wt); 311 312 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) 313 { 314 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB, 315 __builtin_return_address(0)); 316 } 317 EXPORT_SYMBOL(ioremap_cache); 318 319 void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size, 320 unsigned long prot_val) 321 { 322 return __ioremap_caller(phys_addr, size, 323 pgprot2cachemode(__pgprot(prot_val)), 324 __builtin_return_address(0)); 325 } 326 EXPORT_SYMBOL(ioremap_prot); 327 328 /** 329 * iounmap - Free a IO remapping 330 * @addr: virtual address from ioremap_* 331 * 332 * Caller must ensure there is only one unmapping for the same pointer. 333 */ 334 void iounmap(volatile void __iomem *addr) 335 { 336 struct vm_struct *p, *o; 337 338 if ((void __force *)addr <= high_memory) 339 return; 340 341 /* 342 * __ioremap special-cases the PCI/ISA range by not instantiating a 343 * vm_area and by simply returning an address into the kernel mapping 344 * of ISA space. So handle that here. 345 */ 346 if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) && 347 (void __force *)addr < phys_to_virt(ISA_END_ADDRESS)) 348 return; 349 350 addr = (volatile void __iomem *) 351 (PAGE_MASK & (unsigned long __force)addr); 352 353 mmiotrace_iounmap(addr); 354 355 /* Use the vm area unlocked, assuming the caller 356 ensures there isn't another iounmap for the same address 357 in parallel. Reuse of the virtual address is prevented by 358 leaving it in the global lists until we're done with it. 359 cpa takes care of the direct mappings. */ 360 p = find_vm_area((void __force *)addr); 361 362 if (!p) { 363 printk(KERN_ERR "iounmap: bad address %p\n", addr); 364 dump_stack(); 365 return; 366 } 367 368 free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p)); 369 370 /* Finally remove it */ 371 o = remove_vm_area((void __force *)addr); 372 BUG_ON(p != o || o == NULL); 373 kfree(p); 374 } 375 EXPORT_SYMBOL(iounmap); 376 377 int __init arch_ioremap_pud_supported(void) 378 { 379 #ifdef CONFIG_X86_64 380 return boot_cpu_has(X86_FEATURE_GBPAGES); 381 #else 382 return 0; 383 #endif 384 } 385 386 int __init arch_ioremap_pmd_supported(void) 387 { 388 return boot_cpu_has(X86_FEATURE_PSE); 389 } 390 391 /* 392 * Convert a physical pointer to a virtual kernel pointer for /dev/mem 393 * access 394 */ 395 void *xlate_dev_mem_ptr(phys_addr_t phys) 396 { 397 unsigned long start = phys & PAGE_MASK; 398 unsigned long offset = phys & ~PAGE_MASK; 399 void *vaddr; 400 401 /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */ 402 if (page_is_ram(start >> PAGE_SHIFT)) 403 return __va(phys); 404 405 vaddr = ioremap_cache(start, PAGE_SIZE); 406 /* Only add the offset on success and return NULL if the ioremap() failed: */ 407 if (vaddr) 408 vaddr += offset; 409 410 return vaddr; 411 } 412 413 void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr) 414 { 415 if (page_is_ram(phys >> PAGE_SHIFT)) 416 return; 417 418 iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK)); 419 } 420 421 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss; 422 423 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) 424 { 425 /* Don't assume we're using swapper_pg_dir at this point */ 426 pgd_t *base = __va(read_cr3()); 427 pgd_t *pgd = &base[pgd_index(addr)]; 428 pud_t *pud = pud_offset(pgd, addr); 429 pmd_t *pmd = pmd_offset(pud, addr); 430 431 return pmd; 432 } 433 434 static inline pte_t * __init early_ioremap_pte(unsigned long addr) 435 { 436 return &bm_pte[pte_index(addr)]; 437 } 438 439 bool __init is_early_ioremap_ptep(pte_t *ptep) 440 { 441 return ptep >= &bm_pte[0] && ptep < &bm_pte[PAGE_SIZE/sizeof(pte_t)]; 442 } 443 444 void __init early_ioremap_init(void) 445 { 446 pmd_t *pmd; 447 448 #ifdef CONFIG_X86_64 449 BUILD_BUG_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); 450 #else 451 WARN_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); 452 #endif 453 454 early_ioremap_setup(); 455 456 pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); 457 memset(bm_pte, 0, sizeof(bm_pte)); 458 pmd_populate_kernel(&init_mm, pmd, bm_pte); 459 460 /* 461 * The boot-ioremap range spans multiple pmds, for which 462 * we are not prepared: 463 */ 464 #define __FIXADDR_TOP (-PAGE_SIZE) 465 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 466 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 467 #undef __FIXADDR_TOP 468 if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) { 469 WARN_ON(1); 470 printk(KERN_WARNING "pmd %p != %p\n", 471 pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))); 472 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 473 fix_to_virt(FIX_BTMAP_BEGIN)); 474 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n", 475 fix_to_virt(FIX_BTMAP_END)); 476 477 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 478 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n", 479 FIX_BTMAP_BEGIN); 480 } 481 } 482 483 void __init __early_set_fixmap(enum fixed_addresses idx, 484 phys_addr_t phys, pgprot_t flags) 485 { 486 unsigned long addr = __fix_to_virt(idx); 487 pte_t *pte; 488 489 if (idx >= __end_of_fixed_addresses) { 490 BUG(); 491 return; 492 } 493 pte = early_ioremap_pte(addr); 494 495 if (pgprot_val(flags)) 496 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags)); 497 else 498 pte_clear(&init_mm, addr, pte); 499 __flush_tlb_one(addr); 500 } 501