root/arch/arm/mm/ioremap.c

DEFINITIONS

1. find_static_vm_paddr
2. find_static_vm_vaddr
3. add_static_vm_early
4. ioremap_page
5. __check_vmalloc_seq
6. unmap_area_sections
7. remap_area_sections
8. remap_area_supersections
9. __arm_ioremap_pfn_caller
10. __arm_ioremap_caller
11. __arm_ioremap_pfn
12. ioremap
13. ioremap_cache
14. ioremap_wc
15. __arm_ioremap_exec
16. arch_memremap_wb
17. __iounmap
18. iounmap
19. pci_ioremap_set_mem_type
20. pci_ioremap_io
21. pci_remap_cfgspace
22. early_ioremap_init

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/mm/ioremap.c
   4  *
   5  * Re-map IO memory to kernel address space so that we can access it.
   6  *
   7  * (C) Copyright 1995 1996 Linus Torvalds
   8  *
   9  * Hacked for ARM by Phil Blundell <philb@gnu.org>
  10  * Hacked to allow all architectures to build, and various cleanups
  11  * by Russell King
  12  *
  13  * This allows a driver to remap an arbitrary region of bus memory into
  14  * virtual space.  One should *only* use readl, writel, memcpy_toio and
  15  * so on with such remapped areas.
  16  *
  17  * Because the ARM only has a 32-bit address space we can't address the
  18  * whole of the (physical) PCI space at once.  PCI huge-mode addressing
  19  * allows us to circumvent this restriction by splitting PCI space into
  20  * two 2GB chunks and mapping only one at a time into processor memory.
  21  * We use MMU protection domains to trap any attempt to access the bank
  22  * that is not currently mapped.  (This isn't fully implemented yet.)
  23  */
  24 #include <linux/module.h>
  25 #include <linux/errno.h>
  26 #include <linux/mm.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/io.h>
  29 #include <linux/sizes.h>
  30 
  31 #include <asm/cp15.h>
  32 #include <asm/cputype.h>
  33 #include <asm/cacheflush.h>
  34 #include <asm/early_ioremap.h>
  35 #include <asm/mmu_context.h>
  36 #include <asm/pgalloc.h>
  37 #include <asm/tlbflush.h>
  38 #include <asm/system_info.h>
  39 
  40 #include <asm/mach/map.h>
  41 #include <asm/mach/pci.h>
  42 #include "mm.h"
  43 
  44 
  45 LIST_HEAD(static_vmlist);
  46 
  47 static struct static_vm *find_static_vm_paddr(phys_addr_t paddr,
  48                         size_t size, unsigned int mtype)
  49 {
  50         struct static_vm *svm;
  51         struct vm_struct *vm;
  52 
  53         list_for_each_entry(svm, &static_vmlist, list) {
  54                 vm = &svm->vm;
  55                 if (!(vm->flags & VM_ARM_STATIC_MAPPING))
  56                         continue;
  57                 if ((vm->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
  58                         continue;
  59 
  60                 if (vm->phys_addr > paddr ||
  61                         paddr + size - 1 > vm->phys_addr + vm->size - 1)
  62                         continue;
  63 
  64                 return svm;
  65         }
  66 
  67         return NULL;
  68 }
  69 
  70 struct static_vm *find_static_vm_vaddr(void *vaddr)
  71 {
  72         struct static_vm *svm;
  73         struct vm_struct *vm;
  74 
  75         list_for_each_entry(svm, &static_vmlist, list) {
  76                 vm = &svm->vm;
  77 
  78                 /* static_vmlist is ascending order */
  79                 if (vm->addr > vaddr)
  80                         break;
  81 
  82                 if (vm->addr <= vaddr && vm->addr + vm->size > vaddr)
  83                         return svm;
  84         }
  85 
  86         return NULL;
  87 }
  88 
  89 void __init add_static_vm_early(struct static_vm *svm)
  90 {
  91         struct static_vm *curr_svm;
  92         struct vm_struct *vm;
  93         void *vaddr;
  94 
  95         vm = &svm->vm;
  96         vm_area_add_early(vm);
  97         vaddr = vm->addr;
  98 
  99         list_for_each_entry(curr_svm, &static_vmlist, list) {
 100                 vm = &curr_svm->vm;
 101 
 102                 if (vm->addr > vaddr)
 103                         break;
 104         }
 105         list_add_tail(&svm->list, &curr_svm->list);
 106 }
 107 
 108 int ioremap_page(unsigned long virt, unsigned long phys,
 109                  const struct mem_type *mtype)
 110 {
 111         return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
 112                                   __pgprot(mtype->prot_pte));
 113 }
 114 EXPORT_SYMBOL(ioremap_page);
 115 
 116 void __check_vmalloc_seq(struct mm_struct *mm)
 117 {
 118         unsigned int seq;
 119 
 120         do {
 121                 seq = init_mm.context.vmalloc_seq;
 122                 memcpy(pgd_offset(mm, VMALLOC_START),
 123                        pgd_offset_k(VMALLOC_START),
 124                        sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
 125                                         pgd_index(VMALLOC_START)));
 126                 mm->context.vmalloc_seq = seq;
 127         } while (seq != init_mm.context.vmalloc_seq);
 128 }
 129 
 130 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 131 /*
 132  * Section support is unsafe on SMP - If you iounmap and ioremap a region,
 133  * the other CPUs will not see this change until their next context switch.
 134  * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
 135  * which requires the new ioremap'd region to be referenced, the CPU will
 136  * reference the _old_ region.
 137  *
 138  * Note that get_vm_area_caller() allocates a guard 4K page, so we need to
 139  * mask the size back to 1MB aligned or we will overflow in the loop below.
 140  */
 141 static void unmap_area_sections(unsigned long virt, unsigned long size)
 142 {
 143         unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
 144         pgd_t *pgd;
 145         pud_t *pud;
 146         pmd_t *pmdp;
 147 
 148         flush_cache_vunmap(addr, end);
 149         pgd = pgd_offset_k(addr);
 150         pud = pud_offset(pgd, addr);
 151         pmdp = pmd_offset(pud, addr);
 152         do {
 153                 pmd_t pmd = *pmdp;
 154 
 155                 if (!pmd_none(pmd)) {
 156                         /*
 157                          * Clear the PMD from the page table, and
 158                          * increment the vmalloc sequence so others
 159                          * notice this change.
 160                          *
 161                          * Note: this is still racy on SMP machines.
 162                          */
 163                         pmd_clear(pmdp);
 164                         init_mm.context.vmalloc_seq++;
 165 
 166                         /*
 167                          * Free the page table, if there was one.
 168                          */
 169                         if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
 170                                 pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
 171                 }
 172 
 173                 addr += PMD_SIZE;
 174                 pmdp += 2;
 175         } while (addr < end);
 176 
 177         /*
 178          * Ensure that the active_mm is up to date - we want to
 179          * catch any use-after-iounmap cases.
 180          */
 181         if (current->active_mm->context.vmalloc_seq != init_mm.context.vmalloc_seq)
 182                 __check_vmalloc_seq(current->active_mm);
 183 
 184         flush_tlb_kernel_range(virt, end);
 185 }
 186 
 187 static int
 188 remap_area_sections(unsigned long virt, unsigned long pfn,
 189                     size_t size, const struct mem_type *type)
 190 {
 191         unsigned long addr = virt, end = virt + size;
 192         pgd_t *pgd;
 193         pud_t *pud;
 194         pmd_t *pmd;
 195 
 196         /*
 197          * Remove and free any PTE-based mapping, and
 198          * sync the current kernel mapping.
 199          */
 200         unmap_area_sections(virt, size);
 201 
 202         pgd = pgd_offset_k(addr);
 203         pud = pud_offset(pgd, addr);
 204         pmd = pmd_offset(pud, addr);
 205         do {
 206                 pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
 207                 pfn += SZ_1M >> PAGE_SHIFT;
 208                 pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
 209                 pfn += SZ_1M >> PAGE_SHIFT;
 210                 flush_pmd_entry(pmd);
 211 
 212                 addr += PMD_SIZE;
 213                 pmd += 2;
 214         } while (addr < end);
 215 
 216         return 0;
 217 }
 218 
 219 static int
 220 remap_area_supersections(unsigned long virt, unsigned long pfn,
 221                          size_t size, const struct mem_type *type)
 222 {
 223         unsigned long addr = virt, end = virt + size;
 224         pgd_t *pgd;
 225         pud_t *pud;
 226         pmd_t *pmd;
 227 
 228         /*
 229          * Remove and free any PTE-based mapping, and
 230          * sync the current kernel mapping.
 231          */
 232         unmap_area_sections(virt, size);
 233 
 234         pgd = pgd_offset_k(virt);
 235         pud = pud_offset(pgd, addr);
 236         pmd = pmd_offset(pud, addr);
 237         do {
 238                 unsigned long super_pmd_val, i;
 239 
 240                 super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
 241                                 PMD_SECT_SUPER;
 242                 super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
 243 
 244                 for (i = 0; i < 8; i++) {
 245                         pmd[0] = __pmd(super_pmd_val);
 246                         pmd[1] = __pmd(super_pmd_val);
 247                         flush_pmd_entry(pmd);
 248 
 249                         addr += PMD_SIZE;
 250                         pmd += 2;
 251                 }
 252 
 253                 pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
 254         } while (addr < end);
 255 
 256         return 0;
 257 }
 258 #endif
 259 
 260 static void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
 261         unsigned long offset, size_t size, unsigned int mtype, void *caller)
 262 {
 263         const struct mem_type *type;
 264         int err;
 265         unsigned long addr;
 266         struct vm_struct *area;
 267         phys_addr_t paddr = __pfn_to_phys(pfn);
 268 
 269 #ifndef CONFIG_ARM_LPAE
 270         /*
 271          * High mappings must be supersection aligned
 272          */
 273         if (pfn >= 0x100000 && (paddr & ~SUPERSECTION_MASK))
 274                 return NULL;
 275 #endif
 276 
 277         type = get_mem_type(mtype);
 278         if (!type)
 279                 return NULL;
 280 
 281         /*
 282          * Page align the mapping size, taking account of any offset.
 283          */
 284         size = PAGE_ALIGN(offset + size);
 285 
 286         /*
 287          * Try to reuse one of the static mapping whenever possible.
 288          */
 289         if (size && !(sizeof(phys_addr_t) == 4 && pfn >= 0x100000)) {
 290                 struct static_vm *svm;
 291 
 292                 svm = find_static_vm_paddr(paddr, size, mtype);
 293                 if (svm) {
 294                         addr = (unsigned long)svm->vm.addr;
 295                         addr += paddr - svm->vm.phys_addr;
 296                         return (void __iomem *) (offset + addr);
 297                 }
 298         }
 299 
 300         /*
 301          * Don't allow RAM to be mapped with mismatched attributes - this
 302          * causes problems with ARMv6+
 303          */
 304         if (WARN_ON(pfn_valid(pfn) && mtype != MT_MEMORY_RW))
 305                 return NULL;
 306 
 307         area = get_vm_area_caller(size, VM_IOREMAP, caller);
 308         if (!area)
 309                 return NULL;
 310         addr = (unsigned long)area->addr;
 311         area->phys_addr = paddr;
 312 
 313 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 314         if (DOMAIN_IO == 0 &&
 315             (((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
 316                cpu_is_xsc3()) && pfn >= 0x100000 &&
 317                !((paddr | size | addr) & ~SUPERSECTION_MASK)) {
 318                 area->flags |= VM_ARM_SECTION_MAPPING;
 319                 err = remap_area_supersections(addr, pfn, size, type);
 320         } else if (!((paddr | size | addr) & ~PMD_MASK)) {
 321                 area->flags |= VM_ARM_SECTION_MAPPING;
 322                 err = remap_area_sections(addr, pfn, size, type);
 323         } else
 324 #endif
 325                 err = ioremap_page_range(addr, addr + size, paddr,
 326                                          __pgprot(type->prot_pte));
 327 
 328         if (err) {
 329                 vunmap((void *)addr);
 330                 return NULL;
 331         }
 332 
 333         flush_cache_vmap(addr, addr + size);
 334         return (void __iomem *) (offset + addr);
 335 }
 336 
 337 void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
 338         unsigned int mtype, void *caller)
 339 {
 340         phys_addr_t last_addr;
 341         unsigned long offset = phys_addr & ~PAGE_MASK;
 342         unsigned long pfn = __phys_to_pfn(phys_addr);
 343 
 344         /*
 345          * Don't allow wraparound or zero size
 346          */
 347         last_addr = phys_addr + size - 1;
 348         if (!size || last_addr < phys_addr)
 349                 return NULL;
 350 
 351         return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
 352                         caller);
 353 }
 354 
 355 /*
 356  * Remap an arbitrary physical address space into the kernel virtual
 357  * address space. Needed when the kernel wants to access high addresses
 358  * directly.
 359  *
 360  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 361  * have to convert them into an offset in a page-aligned mapping, but the
 362  * caller shouldn't need to know that small detail.
 363  */
 364 void __iomem *
 365 __arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
 366                   unsigned int mtype)
 367 {
 368         return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
 369                                         __builtin_return_address(0));
 370 }
 371 EXPORT_SYMBOL(__arm_ioremap_pfn);
 372 
 373 void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
 374                                       unsigned int, void *) =
 375         __arm_ioremap_caller;
 376 
 377 void __iomem *ioremap(resource_size_t res_cookie, size_t size)
 378 {
 379         return arch_ioremap_caller(res_cookie, size, MT_DEVICE,
 380                                    __builtin_return_address(0));
 381 }
 382 EXPORT_SYMBOL(ioremap);
 383 
 384 void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
 385         __alias(ioremap_cached);
 386 
 387 void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size)
 388 {
 389         return arch_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
 390                                    __builtin_return_address(0));
 391 }
 392 EXPORT_SYMBOL(ioremap_cache);
 393 EXPORT_SYMBOL(ioremap_cached);
 394 
 395 void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
 396 {
 397         return arch_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
 398                                    __builtin_return_address(0));
 399 }
 400 EXPORT_SYMBOL(ioremap_wc);
 401 
 402 /*
 403  * Remap an arbitrary physical address space into the kernel virtual
 404  * address space as memory. Needed when the kernel wants to execute
 405  * code in external memory. This is needed for reprogramming source
 406  * clocks that would affect normal memory for example. Please see
 407  * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
 408  */
 409 void __iomem *
 410 __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached)
 411 {
 412         unsigned int mtype;
 413 
 414         if (cached)
 415                 mtype = MT_MEMORY_RWX;
 416         else
 417                 mtype = MT_MEMORY_RWX_NONCACHED;
 418 
 419         return __arm_ioremap_caller(phys_addr, size, mtype,
 420                         __builtin_return_address(0));
 421 }
 422 
 423 void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 424 {
 425         return (__force void *)arch_ioremap_caller(phys_addr, size,
 426                                                    MT_MEMORY_RW,
 427                                                    __builtin_return_address(0));
 428 }
 429 
 430 void __iounmap(volatile void __iomem *io_addr)
 431 {
 432         void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
 433         struct static_vm *svm;
 434 
 435         /* If this is a static mapping, we must leave it alone */
 436         svm = find_static_vm_vaddr(addr);
 437         if (svm)
 438                 return;
 439 
 440 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 441         {
 442                 struct vm_struct *vm;
 443 
 444                 vm = find_vm_area(addr);
 445 
 446                 /*
 447                  * If this is a section based mapping we need to handle it
 448                  * specially as the VM subsystem does not know how to handle
 449                  * such a beast.
 450                  */
 451                 if (vm && (vm->flags & VM_ARM_SECTION_MAPPING))
 452                         unmap_area_sections((unsigned long)vm->addr, vm->size);
 453         }
 454 #endif
 455 
 456         vunmap(addr);
 457 }
 458 
 459 void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
 460 
 461 void iounmap(volatile void __iomem *cookie)
 462 {
 463         arch_iounmap(cookie);
 464 }
 465 EXPORT_SYMBOL(iounmap);
 466 
 467 #ifdef CONFIG_PCI
 468 static int pci_ioremap_mem_type = MT_DEVICE;
 469 
 470 void pci_ioremap_set_mem_type(int mem_type)
 471 {
 472         pci_ioremap_mem_type = mem_type;
 473 }
 474 
 475 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 476 {
 477         BUG_ON(offset + SZ_64K - 1 > IO_SPACE_LIMIT);
 478 
 479         return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
 480                                   PCI_IO_VIRT_BASE + offset + SZ_64K,
 481                                   phys_addr,
 482                                   __pgprot(get_mem_type(pci_ioremap_mem_type)->prot_pte));
 483 }
 484 EXPORT_SYMBOL_GPL(pci_ioremap_io);
 485 
 486 void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
 487 {
 488         return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
 489                                    __builtin_return_address(0));
 490 }
 491 EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
 492 #endif
 493 
 494 /*
 495  * Must be called after early_fixmap_init
 496  */
 497 void __init early_ioremap_init(void)
 498 {
 499         early_ioremap_setup();
 500 }