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 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, unsigned long prot_val, 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 unsigned long new_prot_val; 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 prot_val, &new_prot_val); 138 if (retval) { 139 printk(KERN_ERR "ioremap reserve_memtype failed %d\n", retval); 140 return NULL; 141 } 142 143 if (prot_val != new_prot_val) { 144 if (!is_new_memtype_allowed(phys_addr, size, 145 prot_val, new_prot_val)) { 146 printk(KERN_ERR 147 "ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n", 148 (unsigned long long)phys_addr, 149 (unsigned long long)(phys_addr + size), 150 prot_val, new_prot_val); 151 goto err_free_memtype; 152 } 153 prot_val = new_prot_val; 154 } 155 156 switch (prot_val) { 157 case _PAGE_CACHE_UC: 158 default: 159 prot = PAGE_KERNEL_IO_NOCACHE; 160 break; 161 case _PAGE_CACHE_UC_MINUS: 162 prot = PAGE_KERNEL_IO_UC_MINUS; 163 break; 164 case _PAGE_CACHE_WC: 165 prot = PAGE_KERNEL_IO_WC; 166 break; 167 case _PAGE_CACHE_WB: 168 prot = PAGE_KERNEL_IO; 169 break; 170 } 171 172 /* 173 * Ok, go for it.. 174 */ 175 area = get_vm_area_caller(size, VM_IOREMAP, caller); 176 if (!area) 177 goto err_free_memtype; 178 area->phys_addr = phys_addr; 179 vaddr = (unsigned long) area->addr; 180 181 if (kernel_map_sync_memtype(phys_addr, size, prot_val)) 182 goto err_free_area; 183 184 if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) 185 goto err_free_area; 186 187 ret_addr = (void __iomem *) (vaddr + offset); 188 mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr); 189 190 /* 191 * Check if the request spans more than any BAR in the iomem resource 192 * tree. 193 */ 194 WARN_ONCE(iomem_map_sanity_check(unaligned_phys_addr, unaligned_size), 195 KERN_INFO "Info: mapping multiple BARs. Your kernel is fine."); 196 197 return ret_addr; 198 err_free_area: 199 free_vm_area(area); 200 err_free_memtype: 201 free_memtype(phys_addr, phys_addr + size); 202 return NULL; 203 } 204 205 /** 206 * ioremap_nocache - map bus memory into CPU space 207 * @phys_addr: bus address of the memory 208 * @size: size of the resource to map 209 * 210 * ioremap_nocache performs a platform specific sequence of operations to 211 * make bus memory CPU accessible via the readb/readw/readl/writeb/ 212 * writew/writel functions and the other mmio helpers. The returned 213 * address is not guaranteed to be usable directly as a virtual 214 * address. 215 * 216 * This version of ioremap ensures that the memory is marked uncachable 217 * on the CPU as well as honouring existing caching rules from things like 218 * the PCI bus. Note that there are other caches and buffers on many 219 * busses. In particular driver authors should read up on PCI writes 220 * 221 * It's useful if some control registers are in such an area and 222 * write combining or read caching is not desirable: 223 * 224 * Must be freed with iounmap. 225 */ 226 void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size) 227 { 228 /* 229 * Ideally, this should be: 230 * pat_enabled ? _PAGE_CACHE_UC : _PAGE_CACHE_UC_MINUS; 231 * 232 * Till we fix all X drivers to use ioremap_wc(), we will use 233 * UC MINUS. 234 */ 235 unsigned long val = _PAGE_CACHE_UC_MINUS; 236 237 return __ioremap_caller(phys_addr, size, val, 238 __builtin_return_address(0)); 239 } 240 EXPORT_SYMBOL(ioremap_nocache); 241 242 /** 243 * ioremap_wc - map memory into CPU space write combined 244 * @phys_addr: bus address of the memory 245 * @size: size of the resource to map 246 * 247 * This version of ioremap ensures that the memory is marked write combining. 248 * Write combining allows faster writes to some hardware devices. 249 * 250 * Must be freed with iounmap. 251 */ 252 void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size) 253 { 254 if (pat_enabled) 255 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WC, 256 __builtin_return_address(0)); 257 else 258 return ioremap_nocache(phys_addr, size); 259 } 260 EXPORT_SYMBOL(ioremap_wc); 261 262 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) 263 { 264 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WB, 265 __builtin_return_address(0)); 266 } 267 EXPORT_SYMBOL(ioremap_cache); 268 269 void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size, 270 unsigned long prot_val) 271 { 272 return __ioremap_caller(phys_addr, size, (prot_val & _PAGE_CACHE_MASK), 273 __builtin_return_address(0)); 274 } 275 EXPORT_SYMBOL(ioremap_prot); 276 277 /** 278 * iounmap - Free a IO remapping 279 * @addr: virtual address from ioremap_* 280 * 281 * Caller must ensure there is only one unmapping for the same pointer. 282 */ 283 void iounmap(volatile void __iomem *addr) 284 { 285 struct vm_struct *p, *o; 286 287 if ((void __force *)addr <= high_memory) 288 return; 289 290 /* 291 * __ioremap special-cases the PCI/ISA range by not instantiating a 292 * vm_area and by simply returning an address into the kernel mapping 293 * of ISA space. So handle that here. 294 */ 295 if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) && 296 (void __force *)addr < phys_to_virt(ISA_END_ADDRESS)) 297 return; 298 299 addr = (volatile void __iomem *) 300 (PAGE_MASK & (unsigned long __force)addr); 301 302 mmiotrace_iounmap(addr); 303 304 /* Use the vm area unlocked, assuming the caller 305 ensures there isn't another iounmap for the same address 306 in parallel. Reuse of the virtual address is prevented by 307 leaving it in the global lists until we're done with it. 308 cpa takes care of the direct mappings. */ 309 p = find_vm_area((void __force *)addr); 310 311 if (!p) { 312 printk(KERN_ERR "iounmap: bad address %p\n", addr); 313 dump_stack(); 314 return; 315 } 316 317 free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p)); 318 319 /* Finally remove it */ 320 o = remove_vm_area((void __force *)addr); 321 BUG_ON(p != o || o == NULL); 322 kfree(p); 323 } 324 EXPORT_SYMBOL(iounmap); 325 326 /* 327 * Convert a physical pointer to a virtual kernel pointer for /dev/mem 328 * access 329 */ 330 void *xlate_dev_mem_ptr(unsigned long phys) 331 { 332 void *addr; 333 unsigned long start = phys & PAGE_MASK; 334 335 /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */ 336 if (page_is_ram(start >> PAGE_SHIFT)) 337 return __va(phys); 338 339 addr = (void __force *)ioremap_cache(start, PAGE_SIZE); 340 if (addr) 341 addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK)); 342 343 return addr; 344 } 345 346 void unxlate_dev_mem_ptr(unsigned long phys, void *addr) 347 { 348 if (page_is_ram(phys >> PAGE_SHIFT)) 349 return; 350 351 iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK)); 352 return; 353 } 354 355 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss; 356 357 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) 358 { 359 /* Don't assume we're using swapper_pg_dir at this point */ 360 pgd_t *base = __va(read_cr3()); 361 pgd_t *pgd = &base[pgd_index(addr)]; 362 pud_t *pud = pud_offset(pgd, addr); 363 pmd_t *pmd = pmd_offset(pud, addr); 364 365 return pmd; 366 } 367 368 static inline pte_t * __init early_ioremap_pte(unsigned long addr) 369 { 370 return &bm_pte[pte_index(addr)]; 371 } 372 373 bool __init is_early_ioremap_ptep(pte_t *ptep) 374 { 375 return ptep >= &bm_pte[0] && ptep < &bm_pte[PAGE_SIZE/sizeof(pte_t)]; 376 } 377 378 void __init early_ioremap_init(void) 379 { 380 pmd_t *pmd; 381 382 #ifdef CONFIG_X86_64 383 BUILD_BUG_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); 384 #else 385 WARN_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); 386 #endif 387 388 early_ioremap_setup(); 389 390 pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); 391 memset(bm_pte, 0, sizeof(bm_pte)); 392 pmd_populate_kernel(&init_mm, pmd, bm_pte); 393 394 /* 395 * The boot-ioremap range spans multiple pmds, for which 396 * we are not prepared: 397 */ 398 #define __FIXADDR_TOP (-PAGE_SIZE) 399 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 400 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 401 #undef __FIXADDR_TOP 402 if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) { 403 WARN_ON(1); 404 printk(KERN_WARNING "pmd %p != %p\n", 405 pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))); 406 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 407 fix_to_virt(FIX_BTMAP_BEGIN)); 408 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n", 409 fix_to_virt(FIX_BTMAP_END)); 410 411 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 412 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n", 413 FIX_BTMAP_BEGIN); 414 } 415 } 416 417 void __init __early_set_fixmap(enum fixed_addresses idx, 418 phys_addr_t phys, pgprot_t flags) 419 { 420 unsigned long addr = __fix_to_virt(idx); 421 pte_t *pte; 422 423 if (idx >= __end_of_fixed_addresses) { 424 BUG(); 425 return; 426 } 427 pte = early_ioremap_pte(addr); 428 429 if (pgprot_val(flags)) 430 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags)); 431 else 432 pte_clear(&init_mm, addr, pte); 433 __flush_tlb_one(addr); 434 } 435