lib/ioremap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Re-map IO memory to kernel address space so that we can access it.
   4  * This is needed for high PCI addresses that aren't mapped in the
   5  * 640k-1MB IO memory area on PC's
   6  *
   7  * (C) Copyright 1995 1996 Linus Torvalds
   8  */
   9 #include <linux/vmalloc.h>
  10 #include <linux/mm.h>
  11 #include <linux/sched.h>
  12 #include <linux/io.h>
  13 #include <linux/export.h>
  14 #include <asm/cacheflush.h>
  15 #include <asm/pgtable.h>
  16
  17 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
  18 static int __read_mostly ioremap_p4d_capable;
  19 static int __read_mostly ioremap_pud_capable;
  20 static int __read_mostly ioremap_pmd_capable;
  21 static int __read_mostly ioremap_huge_disabled;
  22
  23 static int __init set_nohugeiomap(char *str)
  24 {
  25         ioremap_huge_disabled = 1;
  26         return 0;
  27 }
  28 early_param("nohugeiomap", set_nohugeiomap);
  29
  30 void __init ioremap_huge_init(void)
  31 {
  32         if (!ioremap_huge_disabled) {
  33                 if (arch_ioremap_p4d_supported())
  34                         ioremap_p4d_capable = 1;
  35                 if (arch_ioremap_pud_supported())
  36                         ioremap_pud_capable = 1;
  37                 if (arch_ioremap_pmd_supported())
  38                         ioremap_pmd_capable = 1;
  39         }
  40 }
  41
  42 static inline int ioremap_p4d_enabled(void)
  43 {
  44         return ioremap_p4d_capable;
  45 }
  46
  47 static inline int ioremap_pud_enabled(void)
  48 {
  49         return ioremap_pud_capable;
  50 }
  51
  52 static inline int ioremap_pmd_enabled(void)
  53 {
  54         return ioremap_pmd_capable;
  55 }
  56
  57 #else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
  58 static inline int ioremap_p4d_enabled(void) { return 0; }
  59 static inline int ioremap_pud_enabled(void) { return 0; }
  60 static inline int ioremap_pmd_enabled(void) { return 0; }
  61 #endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
  62
  63 static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
  64                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
  65                 pgtbl_mod_mask *mask)
  66 {
  67         pte_t *pte;
  68         u64 pfn;
  69
  70         pfn = phys_addr >> PAGE_SHIFT;
  71         pte = pte_alloc_kernel_track(pmd, addr, mask);
  72         if (!pte)
  73                 return -ENOMEM;
  74         do {
  75                 BUG_ON(!pte_none(*pte));
  76                 set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
  77                 pfn++;
  78         } while (pte++, addr += PAGE_SIZE, addr != end);
  79         *mask |= PGTBL_PTE_MODIFIED;
  80         return 0;
  81 }
  82
  83 static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
  84                                 unsigned long end, phys_addr_t phys_addr,
  85                                 pgprot_t prot)
  86 {
  87         if (!ioremap_pmd_enabled())
  88                 return 0;
  89
  90         if ((end - addr) != PMD_SIZE)
  91                 return 0;
  92
  93         if (!IS_ALIGNED(addr, PMD_SIZE))
  94                 return 0;
  95
  96         if (!IS_ALIGNED(phys_addr, PMD_SIZE))
  97                 return 0;
  98
  99         if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
 100                 return 0;
 101
 102         return pmd_set_huge(pmd, phys_addr, prot);
 103 }
 104
 105 static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
 106                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
 107                 pgtbl_mod_mask *mask)
 108 {
 109         pmd_t *pmd;
 110         unsigned long next;
 111
 112         pmd = pmd_alloc_track(&init_mm, pud, addr, mask);
 113         if (!pmd)
 114                 return -ENOMEM;
 115         do {
 116                 next = pmd_addr_end(addr, end);
 117
 118                 if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) {
 119                         *mask |= PGTBL_PMD_MODIFIED;
 120                         continue;
 121                 }
 122
 123                 if (ioremap_pte_range(pmd, addr, next, phys_addr, prot, mask))
 124                         return -ENOMEM;
 125         } while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
 126         return 0;
 127 }
 128
 129 static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
 130                                 unsigned long end, phys_addr_t phys_addr,
 131                                 pgprot_t prot)
 132 {
 133         if (!ioremap_pud_enabled())
 134                 return 0;
 135
 136         if ((end - addr) != PUD_SIZE)
 137                 return 0;
 138
 139         if (!IS_ALIGNED(addr, PUD_SIZE))
 140                 return 0;
 141
 142         if (!IS_ALIGNED(phys_addr, PUD_SIZE))
 143                 return 0;
 144
 145         if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
 146                 return 0;
 147
 148         return pud_set_huge(pud, phys_addr, prot);
 149 }
 150
 151 static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
 152                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
 153                 pgtbl_mod_mask *mask)
 154 {
 155         pud_t *pud;
 156         unsigned long next;
 157
 158         pud = pud_alloc_track(&init_mm, p4d, addr, mask);
 159         if (!pud)
 160                 return -ENOMEM;
 161         do {
 162                 next = pud_addr_end(addr, end);
 163
 164                 if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot)) {
 165                         *mask |= PGTBL_PUD_MODIFIED;
 166                         continue;
 167                 }
 168
 169                 if (ioremap_pmd_range(pud, addr, next, phys_addr, prot, mask))
 170                         return -ENOMEM;
 171         } while (pud++, phys_addr += (next - addr), addr = next, addr != end);
 172         return 0;
 173 }
 174
 175 static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
 176                                 unsigned long end, phys_addr_t phys_addr,
 177                                 pgprot_t prot)
 178 {
 179         if (!ioremap_p4d_enabled())
 180                 return 0;
 181
 182         if ((end - addr) != P4D_SIZE)
 183                 return 0;
 184
 185         if (!IS_ALIGNED(addr, P4D_SIZE))
 186                 return 0;
 187
 188         if (!IS_ALIGNED(phys_addr, P4D_SIZE))
 189                 return 0;
 190
 191         if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
 192                 return 0;
 193
 194         return p4d_set_huge(p4d, phys_addr, prot);
 195 }
 196
 197 static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
 198                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot,
 199                 pgtbl_mod_mask *mask)
 200 {
 201         p4d_t *p4d;
 202         unsigned long next;
 203
 204         p4d = p4d_alloc_track(&init_mm, pgd, addr, mask);
 205         if (!p4d)
 206                 return -ENOMEM;
 207         do {
 208                 next = p4d_addr_end(addr, end);
 209
 210                 if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot)) {
 211                         *mask |= PGTBL_P4D_MODIFIED;
 212                         continue;
 213                 }
 214
 215                 if (ioremap_pud_range(p4d, addr, next, phys_addr, prot, mask))
 216                         return -ENOMEM;
 217         } while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
 218         return 0;
 219 }
 220
 221 int ioremap_page_range(unsigned long addr,
 222                        unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 223 {
 224         pgd_t *pgd;
 225         unsigned long start;
 226         unsigned long next;
 227         int err;
 228         pgtbl_mod_mask mask = 0;
 229
 230         might_sleep();
 231         BUG_ON(addr >= end);
 232
 233         start = addr;
 234         pgd = pgd_offset_k(addr);
 235         do {
 236                 next = pgd_addr_end(addr, end);
 237                 err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot,
 238                                         &mask);
 239                 if (err)
 240                         break;
 241         } while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
 242
 243         flush_cache_vmap(start, end);
 244
 245         if (mask & ARCH_PAGE_TABLE_SYNC_MASK)
 246                 arch_sync_kernel_mappings(start, end);
 247
 248         return err;
 249 }
 250
 251 #ifdef CONFIG_GENERIC_IOREMAP
 252 void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
 253 {
 254         unsigned long offset, vaddr;
 255         phys_addr_t last_addr;
 256         struct vm_struct *area;
 257
 258         /* Disallow wrap-around or zero size */
 259         last_addr = addr + size - 1;
 260         if (!size || last_addr < addr)
 261                 return NULL;
 262
 263         /* Page-align mappings */
 264         offset = addr & (~PAGE_MASK);
 265         addr -= offset;
 266         size = PAGE_ALIGN(size + offset);
 267
 268         area = get_vm_area_caller(size, VM_IOREMAP,
 269                         __builtin_return_address(0));
 270         if (!area)
 271                 return NULL;
 272         vaddr = (unsigned long)area->addr;
 273
 274         if (ioremap_page_range(vaddr, vaddr + size, addr, __pgprot(prot))) {
 275                 free_vm_area(area);
 276                 return NULL;
 277         }
 278
 279         return (void __iomem *)(vaddr + offset);
 280 }
 281 EXPORT_SYMBOL(ioremap_prot);
 282
 283 void iounmap(volatile void __iomem *addr)
 284 {
 285         vunmap((void *)((unsigned long)addr & PAGE_MASK));
 286 }
 287 EXPORT_SYMBOL(iounmap);
 288 #endif /* CONFIG_GENERIC_IOREMAP */