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 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 23 enum ioremap_mode { 24 IOR_MODE_UNCACHED, 25 IOR_MODE_CACHED, 26 }; 27 28 #ifdef CONFIG_X86_64 29 30 unsigned long __phys_addr(unsigned long x) 31 { 32 if (x >= __START_KERNEL_map) 33 return x - __START_KERNEL_map + phys_base; 34 return x - PAGE_OFFSET; 35 } 36 EXPORT_SYMBOL(__phys_addr); 37 38 #endif 39 40 int page_is_ram(unsigned long pagenr) 41 { 42 unsigned long addr, end; 43 int i; 44 45 for (i = 0; i < e820.nr_map; i++) { 46 /* 47 * Not usable memory: 48 */ 49 if (e820.map[i].type != E820_RAM) 50 continue; 51 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT; 52 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT; 53 54 /* 55 * Sanity check: Some BIOSen report areas as RAM that 56 * are not. Notably the 640->1Mb area, which is the 57 * PCI BIOS area. 58 */ 59 if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) && 60 end < (BIOS_END >> PAGE_SHIFT)) 61 continue; 62 63 if ((pagenr >= addr) && (pagenr < end)) 64 return 1; 65 } 66 return 0; 67 } 68 69 /* 70 * Fix up the linear direct mapping of the kernel to avoid cache attribute 71 * conflicts. 72 */ 73 static int ioremap_change_attr(unsigned long paddr, unsigned long size, 74 enum ioremap_mode mode) 75 { 76 unsigned long vaddr = (unsigned long)__va(paddr); 77 unsigned long nrpages = size >> PAGE_SHIFT; 78 unsigned int level; 79 int err; 80 81 /* No change for pages after the last mapping */ 82 if ((paddr + size - 1) >= (max_pfn_mapped << PAGE_SHIFT)) 83 return 0; 84 85 /* 86 * If there is no identity map for this address, 87 * change_page_attr_addr is unnecessary 88 */ 89 if (!lookup_address(vaddr, &level)) 90 return 0; 91 92 switch (mode) { 93 case IOR_MODE_UNCACHED: 94 default: 95 err = set_memory_uc(vaddr, nrpages); 96 break; 97 case IOR_MODE_CACHED: 98 err = set_memory_wb(vaddr, nrpages); 99 break; 100 } 101 102 return err; 103 } 104 105 /* 106 * Remap an arbitrary physical address space into the kernel virtual 107 * address space. Needed when the kernel wants to access high addresses 108 * directly. 109 * 110 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 111 * have to convert them into an offset in a page-aligned mapping, but the 112 * caller shouldn't need to know that small detail. 113 */ 114 static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size, 115 enum ioremap_mode mode) 116 { 117 void __iomem *addr; 118 struct vm_struct *area; 119 unsigned long offset, last_addr; 120 pgprot_t prot; 121 122 /* Don't allow wraparound or zero size */ 123 last_addr = phys_addr + size - 1; 124 if (!size || last_addr < phys_addr) 125 return NULL; 126 127 /* 128 * Don't remap the low PCI/ISA area, it's always mapped.. 129 */ 130 if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS) 131 return (__force void __iomem *)phys_to_virt(phys_addr); 132 133 /* 134 * Don't allow anybody to remap normal RAM that we're using.. 135 */ 136 for (offset = phys_addr >> PAGE_SHIFT; offset < max_pfn_mapped && 137 (offset << PAGE_SHIFT) < last_addr; offset++) { 138 if (page_is_ram(offset)) 139 return NULL; 140 } 141 142 switch (mode) { 143 case IOR_MODE_UNCACHED: 144 default: 145 prot = PAGE_KERNEL_NOCACHE; 146 break; 147 case IOR_MODE_CACHED: 148 prot = PAGE_KERNEL; 149 break; 150 } 151 152 /* 153 * Mappings have to be page-aligned 154 */ 155 offset = phys_addr & ~PAGE_MASK; 156 phys_addr &= PAGE_MASK; 157 size = PAGE_ALIGN(last_addr+1) - phys_addr; 158 159 /* 160 * Ok, go for it.. 161 */ 162 area = get_vm_area(size, VM_IOREMAP); 163 if (!area) 164 return NULL; 165 area->phys_addr = phys_addr; 166 addr = (void __iomem *) area->addr; 167 if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size, 168 phys_addr, prot)) { 169 remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr)); 170 return NULL; 171 } 172 173 if (ioremap_change_attr(phys_addr, size, mode) < 0) { 174 vunmap(addr); 175 return NULL; 176 } 177 178 return (void __iomem *) (offset + (char __iomem *)addr); 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(unsigned long phys_addr, unsigned long size) 203 { 204 return __ioremap(phys_addr, size, IOR_MODE_UNCACHED); 205 } 206 EXPORT_SYMBOL(ioremap_nocache); 207 208 void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size) 209 { 210 return __ioremap(phys_addr, size, IOR_MODE_CACHED); 211 } 212 EXPORT_SYMBOL(ioremap_cache); 213 214 /** 215 * iounmap - Free a IO remapping 216 * @addr: virtual address from ioremap_* 217 * 218 * Caller must ensure there is only one unmapping for the same pointer. 219 */ 220 void iounmap(volatile void __iomem *addr) 221 { 222 struct vm_struct *p, *o; 223 224 if ((void __force *)addr <= high_memory) 225 return; 226 227 /* 228 * __ioremap special-cases the PCI/ISA range by not instantiating a 229 * vm_area and by simply returning an address into the kernel mapping 230 * of ISA space. So handle that here. 231 */ 232 if (addr >= phys_to_virt(ISA_START_ADDRESS) && 233 addr < phys_to_virt(ISA_END_ADDRESS)) 234 return; 235 236 addr = (volatile void __iomem *) 237 (PAGE_MASK & (unsigned long __force)addr); 238 239 /* Use the vm area unlocked, assuming the caller 240 ensures there isn't another iounmap for the same address 241 in parallel. Reuse of the virtual address is prevented by 242 leaving it in the global lists until we're done with it. 243 cpa takes care of the direct mappings. */ 244 read_lock(&vmlist_lock); 245 for (p = vmlist; p; p = p->next) { 246 if (p->addr == addr) 247 break; 248 } 249 read_unlock(&vmlist_lock); 250 251 if (!p) { 252 printk(KERN_ERR "iounmap: bad address %p\n", addr); 253 dump_stack(); 254 return; 255 } 256 257 /* Reset the direct mapping. Can block */ 258 ioremap_change_attr(p->phys_addr, p->size, IOR_MODE_CACHED); 259 260 /* Finally remove it */ 261 o = remove_vm_area((void *)addr); 262 BUG_ON(p != o || o == NULL); 263 kfree(p); 264 } 265 EXPORT_SYMBOL(iounmap); 266 267 #ifdef CONFIG_X86_32 268 269 int __initdata early_ioremap_debug; 270 271 static int __init early_ioremap_debug_setup(char *str) 272 { 273 early_ioremap_debug = 1; 274 275 return 0; 276 } 277 early_param("early_ioremap_debug", early_ioremap_debug_setup); 278 279 static __initdata int after_paging_init; 280 static __initdata unsigned long bm_pte[1024] 281 __attribute__((aligned(PAGE_SIZE))); 282 283 static inline unsigned long * __init early_ioremap_pgd(unsigned long addr) 284 { 285 return (unsigned long *)swapper_pg_dir + ((addr >> 22) & 1023); 286 } 287 288 static inline unsigned long * __init early_ioremap_pte(unsigned long addr) 289 { 290 return bm_pte + ((addr >> PAGE_SHIFT) & 1023); 291 } 292 293 void __init early_ioremap_init(void) 294 { 295 unsigned long *pgd; 296 297 if (early_ioremap_debug) 298 printk(KERN_INFO "early_ioremap_init()\n"); 299 300 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN)); 301 *pgd = __pa(bm_pte) | _PAGE_TABLE; 302 memset(bm_pte, 0, sizeof(bm_pte)); 303 /* 304 * The boot-ioremap range spans multiple pgds, for which 305 * we are not prepared: 306 */ 307 if (pgd != early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))) { 308 WARN_ON(1); 309 printk(KERN_WARNING "pgd %p != %p\n", 310 pgd, early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))); 311 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 312 fix_to_virt(FIX_BTMAP_BEGIN)); 313 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n", 314 fix_to_virt(FIX_BTMAP_END)); 315 316 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 317 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n", 318 FIX_BTMAP_BEGIN); 319 } 320 } 321 322 void __init early_ioremap_clear(void) 323 { 324 unsigned long *pgd; 325 326 if (early_ioremap_debug) 327 printk(KERN_INFO "early_ioremap_clear()\n"); 328 329 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN)); 330 *pgd = 0; 331 paravirt_release_pt(__pa(pgd) >> PAGE_SHIFT); 332 __flush_tlb_all(); 333 } 334 335 void __init early_ioremap_reset(void) 336 { 337 enum fixed_addresses idx; 338 unsigned long *pte, phys, addr; 339 340 after_paging_init = 1; 341 for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) { 342 addr = fix_to_virt(idx); 343 pte = early_ioremap_pte(addr); 344 if (*pte & _PAGE_PRESENT) { 345 phys = *pte & PAGE_MASK; 346 set_fixmap(idx, phys); 347 } 348 } 349 } 350 351 static void __init __early_set_fixmap(enum fixed_addresses idx, 352 unsigned long phys, pgprot_t flags) 353 { 354 unsigned long *pte, addr = __fix_to_virt(idx); 355 356 if (idx >= __end_of_fixed_addresses) { 357 BUG(); 358 return; 359 } 360 pte = early_ioremap_pte(addr); 361 if (pgprot_val(flags)) 362 *pte = (phys & PAGE_MASK) | pgprot_val(flags); 363 else 364 *pte = 0; 365 __flush_tlb_one(addr); 366 } 367 368 static inline void __init early_set_fixmap(enum fixed_addresses idx, 369 unsigned long phys) 370 { 371 if (after_paging_init) 372 set_fixmap(idx, phys); 373 else 374 __early_set_fixmap(idx, phys, PAGE_KERNEL); 375 } 376 377 static inline void __init early_clear_fixmap(enum fixed_addresses idx) 378 { 379 if (after_paging_init) 380 clear_fixmap(idx); 381 else 382 __early_set_fixmap(idx, 0, __pgprot(0)); 383 } 384 385 386 int __initdata early_ioremap_nested; 387 388 static int __init check_early_ioremap_leak(void) 389 { 390 if (!early_ioremap_nested) 391 return 0; 392 393 printk(KERN_WARNING 394 "Debug warning: early ioremap leak of %d areas detected.\n", 395 early_ioremap_nested); 396 printk(KERN_WARNING 397 "please boot with early_ioremap_debug and report the dmesg.\n"); 398 WARN_ON(1); 399 400 return 1; 401 } 402 late_initcall(check_early_ioremap_leak); 403 404 void __init *early_ioremap(unsigned long phys_addr, unsigned long size) 405 { 406 unsigned long offset, last_addr; 407 unsigned int nrpages, nesting; 408 enum fixed_addresses idx0, idx; 409 410 WARN_ON(system_state != SYSTEM_BOOTING); 411 412 nesting = early_ioremap_nested; 413 if (early_ioremap_debug) { 414 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ", 415 phys_addr, size, nesting); 416 dump_stack(); 417 } 418 419 /* Don't allow wraparound or zero size */ 420 last_addr = phys_addr + size - 1; 421 if (!size || last_addr < phys_addr) { 422 WARN_ON(1); 423 return NULL; 424 } 425 426 if (nesting >= FIX_BTMAPS_NESTING) { 427 WARN_ON(1); 428 return NULL; 429 } 430 early_ioremap_nested++; 431 /* 432 * Mappings have to be page-aligned 433 */ 434 offset = phys_addr & ~PAGE_MASK; 435 phys_addr &= PAGE_MASK; 436 size = PAGE_ALIGN(last_addr) - phys_addr; 437 438 /* 439 * Mappings have to fit in the FIX_BTMAP area. 440 */ 441 nrpages = size >> PAGE_SHIFT; 442 if (nrpages > NR_FIX_BTMAPS) { 443 WARN_ON(1); 444 return NULL; 445 } 446 447 /* 448 * Ok, go for it.. 449 */ 450 idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting; 451 idx = idx0; 452 while (nrpages > 0) { 453 early_set_fixmap(idx, phys_addr); 454 phys_addr += PAGE_SIZE; 455 --idx; 456 --nrpages; 457 } 458 if (early_ioremap_debug) 459 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0)); 460 461 return (void *) (offset + fix_to_virt(idx0)); 462 } 463 464 void __init early_iounmap(void *addr, unsigned long size) 465 { 466 unsigned long virt_addr; 467 unsigned long offset; 468 unsigned int nrpages; 469 enum fixed_addresses idx; 470 unsigned int nesting; 471 472 nesting = --early_ioremap_nested; 473 WARN_ON(nesting < 0); 474 475 if (early_ioremap_debug) { 476 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr, 477 size, nesting); 478 dump_stack(); 479 } 480 481 virt_addr = (unsigned long)addr; 482 if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) { 483 WARN_ON(1); 484 return; 485 } 486 offset = virt_addr & ~PAGE_MASK; 487 nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT; 488 489 idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting; 490 while (nrpages > 0) { 491 early_clear_fixmap(idx); 492 --idx; 493 --nrpages; 494 } 495 } 496 497 void __this_fixmap_does_not_exist(void) 498 { 499 WARN_ON(1); 500 } 501 502 #endif /* CONFIG_X86_32 */ 503