arch/arm/mm/ioremap.c

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