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 enum page_cache_mode pcm) 33 { 34 unsigned long nrpages = size >> PAGE_SHIFT; 35 int err; 36 37 switch (pcm) { 38 case _PAGE_CACHE_MODE_UC: 39 default: 40 err = _set_memory_uc(vaddr, nrpages); 41 break; 42 case _PAGE_CACHE_MODE_WC: 43 err = _set_memory_wc(vaddr, nrpages); 44 break; 45 case _PAGE_CACHE_MODE_WB: 46 err = _set_memory_wb(vaddr, nrpages); 47 break; 48 } 49 50 return err; 51 } 52 53 static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages, 54 void *arg) 55 { 56 unsigned long i; 57 58 for (i = 0; i < nr_pages; ++i) 59 if (pfn_valid(start_pfn + i) && 60 !PageReserved(pfn_to_page(start_pfn + i))) 61 return 1; 62 63 WARN_ONCE(1, "ioremap on RAM pfn 0x%lx\n", start_pfn); 64 65 return 0; 66 } 67 68 /* 69 * Remap an arbitrary physical address space into the kernel virtual 70 * address space. Needed when the kernel wants to access high addresses 71 * directly. 72 * 73 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 74 * have to convert them into an offset in a page-aligned mapping, but the 75 * caller shouldn't need to know that small detail. 76 */ 77 static void __iomem *__ioremap_caller(resource_size_t phys_addr, 78 unsigned long size, enum page_cache_mode pcm, void *caller) 79 { 80 unsigned long offset, vaddr; 81 resource_size_t pfn, last_pfn, last_addr; 82 const resource_size_t unaligned_phys_addr = phys_addr; 83 const unsigned long unaligned_size = size; 84 struct vm_struct *area; 85 enum page_cache_mode new_pcm; 86 pgprot_t prot; 87 int retval; 88 void __iomem *ret_addr; 89 int ram_region; 90 91 /* Don't allow wraparound or zero size */ 92 last_addr = phys_addr + size - 1; 93 if (!size || last_addr < phys_addr) 94 return NULL; 95 96 if (!phys_addr_valid(phys_addr)) { 97 printk(KERN_WARNING "ioremap: invalid physical address %llx\n", 98 (unsigned long long)phys_addr); 99 WARN_ON_ONCE(1); 100 return NULL; 101 } 102 103 /* 104 * Don't remap the low PCI/ISA area, it's always mapped.. 105 */ 106 if (is_ISA_range(phys_addr, last_addr)) 107 return (__force void __iomem *)phys_to_virt(phys_addr); 108 109 /* 110 * Don't allow anybody to remap normal RAM that we're using.. 111 */ 112 /* First check if whole region can be identified as RAM or not */ 113 ram_region = region_is_ram(phys_addr, size); 114 if (ram_region > 0) { 115 WARN_ONCE(1, "ioremap on RAM at 0x%lx - 0x%lx\n", 116 (unsigned long int)phys_addr, 117 (unsigned long int)last_addr); 118 return NULL; 119 } 120 121 /* If could not be identified(-1), check page by page */ 122 if (ram_region < 0) { 123 pfn = phys_addr >> PAGE_SHIFT; 124 last_pfn = last_addr >> PAGE_SHIFT; 125 if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL, 126 __ioremap_check_ram) == 1) 127 return NULL; 128 } 129 /* 130 * Mappings have to be page-aligned 131 */ 132 offset = phys_addr & ~PAGE_MASK; 133 phys_addr &= PHYSICAL_PAGE_MASK; 134 size = PAGE_ALIGN(last_addr+1) - phys_addr; 135 136 retval = reserve_memtype(phys_addr, (u64)phys_addr + size, 137 pcm, &new_pcm); 138 if (retval) { 139 printk(KERN_ERR "ioremap reserve_memtype failed %d\n", retval); 140 return NULL; 141 } 142 143 if (pcm != new_pcm) { 144 if (!is_new_memtype_allowed(phys_addr, size, pcm, new_pcm)) { 145 printk(KERN_ERR 146 "ioremap error for 0x%llx-0x%llx, requested 0x%x, got 0x%x\n", 147 (unsigned long long)phys_addr, 148 (unsigned long long)(phys_addr + size), 149 pcm, new_pcm); 150 goto err_free_memtype; 151 } 152 pcm = new_pcm; 153 } 154 155 prot = PAGE_KERNEL_IO; 156 switch (pcm) { 157 case _PAGE_CACHE_MODE_UC: 158 default: 159 prot = __pgprot(pgprot_val(prot) | 160 cachemode2protval(_PAGE_CACHE_MODE_UC)); 161 break; 162 case _PAGE_CACHE_MODE_UC_MINUS: 163 prot = __pgprot(pgprot_val(prot) | 164 cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS)); 165 break; 166 case _PAGE_CACHE_MODE_WC: 167 prot = __pgprot(pgprot_val(prot) | 168 cachemode2protval(_PAGE_CACHE_MODE_WC)); 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 WARN_ONCE(iomem_map_sanity_check(unaligned_phys_addr, unaligned_size), 197 KERN_INFO "Info: mapping multiple BARs. Your kernel is fine."); 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. 236 */ 237 enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC_MINUS; 238 239 return __ioremap_caller(phys_addr, size, pcm, 240 __builtin_return_address(0)); 241 } 242 EXPORT_SYMBOL(ioremap_nocache); 243 244 /** 245 * ioremap_wc - map memory into CPU space write combined 246 * @phys_addr: bus address of the memory 247 * @size: size of the resource to map 248 * 249 * This version of ioremap ensures that the memory is marked write combining. 250 * Write combining allows faster writes to some hardware devices. 251 * 252 * Must be freed with iounmap. 253 */ 254 void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size) 255 { 256 if (pat_enabled) 257 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC, 258 __builtin_return_address(0)); 259 else 260 return ioremap_nocache(phys_addr, size); 261 } 262 EXPORT_SYMBOL(ioremap_wc); 263 264 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) 265 { 266 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB, 267 __builtin_return_address(0)); 268 } 269 EXPORT_SYMBOL(ioremap_cache); 270 271 void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size, 272 unsigned long prot_val) 273 { 274 return __ioremap_caller(phys_addr, size, 275 pgprot2cachemode(__pgprot(prot_val)), 276 __builtin_return_address(0)); 277 } 278 EXPORT_SYMBOL(ioremap_prot); 279 280 /** 281 * iounmap - Free a IO remapping 282 * @addr: virtual address from ioremap_* 283 * 284 * Caller must ensure there is only one unmapping for the same pointer. 285 */ 286 void iounmap(volatile void __iomem *addr) 287 { 288 struct vm_struct *p, *o; 289 290 if ((void __force *)addr <= high_memory) 291 return; 292 293 /* 294 * __ioremap special-cases the PCI/ISA range by not instantiating a 295 * vm_area and by simply returning an address into the kernel mapping 296 * of ISA space. So handle that here. 297 */ 298 if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) && 299 (void __force *)addr < phys_to_virt(ISA_END_ADDRESS)) 300 return; 301 302 addr = (volatile void __iomem *) 303 (PAGE_MASK & (unsigned long __force)addr); 304 305 mmiotrace_iounmap(addr); 306 307 /* Use the vm area unlocked, assuming the caller 308 ensures there isn't another iounmap for the same address 309 in parallel. Reuse of the virtual address is prevented by 310 leaving it in the global lists until we're done with it. 311 cpa takes care of the direct mappings. */ 312 p = find_vm_area((void __force *)addr); 313 314 if (!p) { 315 printk(KERN_ERR "iounmap: bad address %p\n", addr); 316 dump_stack(); 317 return; 318 } 319 320 free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p)); 321 322 /* Finally remove it */ 323 o = remove_vm_area((void __force *)addr); 324 BUG_ON(p != o || o == NULL); 325 kfree(p); 326 } 327 EXPORT_SYMBOL(iounmap); 328 329 /* 330 * Convert a physical pointer to a virtual kernel pointer for /dev/mem 331 * access 332 */ 333 void *xlate_dev_mem_ptr(phys_addr_t phys) 334 { 335 void *addr; 336 unsigned long start = phys & PAGE_MASK; 337 338 /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */ 339 if (page_is_ram(start >> PAGE_SHIFT)) 340 return __va(phys); 341 342 addr = (void __force *)ioremap_cache(start, PAGE_SIZE); 343 if (addr) 344 addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK)); 345 346 return addr; 347 } 348 349 void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr) 350 { 351 if (page_is_ram(phys >> PAGE_SHIFT)) 352 return; 353 354 iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK)); 355 return; 356 } 357 358 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss; 359 360 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) 361 { 362 /* Don't assume we're using swapper_pg_dir at this point */ 363 pgd_t *base = __va(read_cr3()); 364 pgd_t *pgd = &base[pgd_index(addr)]; 365 pud_t *pud = pud_offset(pgd, addr); 366 pmd_t *pmd = pmd_offset(pud, addr); 367 368 return pmd; 369 } 370 371 static inline pte_t * __init early_ioremap_pte(unsigned long addr) 372 { 373 return &bm_pte[pte_index(addr)]; 374 } 375 376 bool __init is_early_ioremap_ptep(pte_t *ptep) 377 { 378 return ptep >= &bm_pte[0] && ptep < &bm_pte[PAGE_SIZE/sizeof(pte_t)]; 379 } 380 381 void __init early_ioremap_init(void) 382 { 383 pmd_t *pmd; 384 385 #ifdef CONFIG_X86_64 386 BUILD_BUG_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); 387 #else 388 WARN_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); 389 #endif 390 391 early_ioremap_setup(); 392 393 pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); 394 memset(bm_pte, 0, sizeof(bm_pte)); 395 pmd_populate_kernel(&init_mm, pmd, bm_pte); 396 397 /* 398 * The boot-ioremap range spans multiple pmds, for which 399 * we are not prepared: 400 */ 401 #define __FIXADDR_TOP (-PAGE_SIZE) 402 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 403 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 404 #undef __FIXADDR_TOP 405 if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) { 406 WARN_ON(1); 407 printk(KERN_WARNING "pmd %p != %p\n", 408 pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))); 409 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 410 fix_to_virt(FIX_BTMAP_BEGIN)); 411 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n", 412 fix_to_virt(FIX_BTMAP_END)); 413 414 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 415 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n", 416 FIX_BTMAP_BEGIN); 417 } 418 } 419 420 void __init __early_set_fixmap(enum fixed_addresses idx, 421 phys_addr_t phys, pgprot_t flags) 422 { 423 unsigned long addr = __fix_to_virt(idx); 424 pte_t *pte; 425 426 if (idx >= __end_of_fixed_addresses) { 427 BUG(); 428 return; 429 } 430 pte = early_ioremap_pte(addr); 431 432 if (pgprot_val(flags)) 433 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags)); 434 else 435 pte_clear(&init_mm, addr, pte); 436 __flush_tlb_one(addr); 437 } 438