include/linux/highmem-internal.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_HIGHMEM_INTERNAL_H
   3 #define _LINUX_HIGHMEM_INTERNAL_H
   4
   5 /*
   6  * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
   7  */
   8 #ifdef CONFIG_KMAP_LOCAL
   9 void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
  10 void *__kmap_local_page_prot(struct page *page, pgprot_t prot);
  11 void kunmap_local_indexed(const void *vaddr);
  12 void kmap_local_fork(struct task_struct *tsk);
  13 void __kmap_local_sched_out(void);
  14 void __kmap_local_sched_in(void);
  15 static inline void kmap_assert_nomap(void)
  16 {
  17         DEBUG_LOCKS_WARN_ON(current->kmap_ctrl.idx);
  18 }
  19 #else
  20 static inline void kmap_local_fork(struct task_struct *tsk) { }
  21 static inline void kmap_assert_nomap(void) { }
  22 #endif
  23
  24 #ifdef CONFIG_HIGHMEM
  25 #include <asm/highmem.h>
  26
  27 #ifndef ARCH_HAS_KMAP_FLUSH_TLB
  28 static inline void kmap_flush_tlb(unsigned long addr) { }
  29 #endif
  30
  31 #ifndef kmap_prot
  32 #define kmap_prot PAGE_KERNEL
  33 #endif
  34
  35 void *kmap_high(struct page *page);
  36 void kunmap_high(struct page *page);
  37 void __kmap_flush_unused(void);
  38 struct page *__kmap_to_page(void *addr);
  39
  40 static inline void *kmap(struct page *page)
  41 {
  42         void *addr;
  43
  44         might_sleep();
  45         if (!PageHighMem(page))
  46                 addr = page_address(page);
  47         else
  48                 addr = kmap_high(page);
  49         kmap_flush_tlb((unsigned long)addr);
  50         return addr;
  51 }
  52
  53 static inline void kunmap(struct page *page)
  54 {
  55         might_sleep();
  56         if (!PageHighMem(page))
  57                 return;
  58         kunmap_high(page);
  59 }
  60
  61 static inline struct page *kmap_to_page(void *addr)
  62 {
  63         return __kmap_to_page(addr);
  64 }
  65
  66 static inline void kmap_flush_unused(void)
  67 {
  68         __kmap_flush_unused();
  69 }
  70
  71 static inline void *kmap_local_page(struct page *page)
  72 {
  73         return __kmap_local_page_prot(page, kmap_prot);
  74 }
  75
  76 static inline void *kmap_local_folio(struct folio *folio, size_t offset)
  77 {
  78         struct page *page = folio_page(folio, offset / PAGE_SIZE);
  79         return __kmap_local_page_prot(page, kmap_prot) + offset % PAGE_SIZE;
  80 }
  81
  82 static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
  83 {
  84         return __kmap_local_page_prot(page, prot);
  85 }
  86
  87 static inline void *kmap_local_pfn(unsigned long pfn)
  88 {
  89         return __kmap_local_pfn_prot(pfn, kmap_prot);
  90 }
  91
  92 static inline void __kunmap_local(const void *vaddr)
  93 {
  94         kunmap_local_indexed(vaddr);
  95 }
  96
  97 static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
  98 {
  99         if (IS_ENABLED(CONFIG_PREEMPT_RT))
 100                 migrate_disable();
 101         else
 102                 preempt_disable();
 103
 104         pagefault_disable();
 105         return __kmap_local_page_prot(page, prot);
 106 }
 107
 108 static inline void *kmap_atomic(struct page *page)
 109 {
 110         return kmap_atomic_prot(page, kmap_prot);
 111 }
 112
 113 static inline void *kmap_atomic_pfn(unsigned long pfn)
 114 {
 115         if (IS_ENABLED(CONFIG_PREEMPT_RT))
 116                 migrate_disable();
 117         else
 118                 preempt_disable();
 119
 120         pagefault_disable();
 121         return __kmap_local_pfn_prot(pfn, kmap_prot);
 122 }
 123
 124 static inline void __kunmap_atomic(const void *addr)
 125 {
 126         kunmap_local_indexed(addr);
 127         pagefault_enable();
 128         if (IS_ENABLED(CONFIG_PREEMPT_RT))
 129                 migrate_enable();
 130         else
 131                 preempt_enable();
 132 }
 133
 134 unsigned long __nr_free_highpages(void);
 135 unsigned long __totalhigh_pages(void);
 136
 137 static inline unsigned long nr_free_highpages(void)
 138 {
 139         return __nr_free_highpages();
 140 }
 141
 142 static inline unsigned long totalhigh_pages(void)
 143 {
 144         return __totalhigh_pages();
 145 }
 146
 147 static inline bool is_kmap_addr(const void *x)
 148 {
 149         unsigned long addr = (unsigned long)x;
 150
 151         return (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) ||
 152                 (addr >= __fix_to_virt(FIX_KMAP_END) &&
 153                  addr < __fix_to_virt(FIX_KMAP_BEGIN));
 154 }
 155 #else /* CONFIG_HIGHMEM */
 156
 157 static inline struct page *kmap_to_page(void *addr)
 158 {
 159         return virt_to_page(addr);
 160 }
 161
 162 static inline void *kmap(struct page *page)
 163 {
 164         might_sleep();
 165         return page_address(page);
 166 }
 167
 168 static inline void kunmap_high(struct page *page) { }
 169 static inline void kmap_flush_unused(void) { }
 170
 171 static inline void kunmap(struct page *page)
 172 {
 173 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
 174         kunmap_flush_on_unmap(page_address(page));
 175 #endif
 176 }
 177
 178 static inline void *kmap_local_page(struct page *page)
 179 {
 180         return page_address(page);
 181 }
 182
 183 static inline void *kmap_local_folio(struct folio *folio, size_t offset)
 184 {
 185         return page_address(&folio->page) + offset;
 186 }
 187
 188 static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
 189 {
 190         return kmap_local_page(page);
 191 }
 192
 193 static inline void *kmap_local_pfn(unsigned long pfn)
 194 {
 195         return kmap_local_page(pfn_to_page(pfn));
 196 }
 197
 198 static inline void __kunmap_local(const void *addr)
 199 {
 200 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
 201         kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
 202 #endif
 203 }
 204
 205 static inline void *kmap_atomic(struct page *page)
 206 {
 207         if (IS_ENABLED(CONFIG_PREEMPT_RT))
 208                 migrate_disable();
 209         else
 210                 preempt_disable();
 211         pagefault_disable();
 212         return page_address(page);
 213 }
 214
 215 static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 216 {
 217         return kmap_atomic(page);
 218 }
 219
 220 static inline void *kmap_atomic_pfn(unsigned long pfn)
 221 {
 222         return kmap_atomic(pfn_to_page(pfn));
 223 }
 224
 225 static inline void __kunmap_atomic(const void *addr)
 226 {
 227 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
 228         kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
 229 #endif
 230         pagefault_enable();
 231         if (IS_ENABLED(CONFIG_PREEMPT_RT))
 232                 migrate_enable();
 233         else
 234                 preempt_enable();
 235 }
 236
 237 static inline unsigned long nr_free_highpages(void) { return 0; }
 238 static inline unsigned long totalhigh_pages(void) { return 0; }
 239
 240 static inline bool is_kmap_addr(const void *x)
 241 {
 242         return false;
 243 }
 244
 245 #endif /* CONFIG_HIGHMEM */
 246
 247 /**
 248  * kunmap_atomic - Unmap the virtual address mapped by kmap_atomic() - deprecated!
 249  * @__addr:       Virtual address to be unmapped
 250  *
 251  * Unmaps an address previously mapped by kmap_atomic() and re-enables
 252  * pagefaults. Depending on PREEMP_RT configuration, re-enables also
 253  * migration and preemption. Users should not count on these side effects.
 254  *
 255  * Mappings should be unmapped in the reverse order that they were mapped.
 256  * See kmap_local_page() for details on nesting.
 257  *
 258  * @__addr can be any address within the mapped page, so there is no need
 259  * to subtract any offset that has been added. In contrast to kunmap(),
 260  * this function takes the address returned from kmap_atomic(), not the
 261  * page passed to it. The compiler will warn you if you pass the page.
 262  */
 263 #define kunmap_atomic(__addr)                                   \
 264 do {                                                            \
 265         BUILD_BUG_ON(__same_type((__addr), struct page *));     \
 266         __kunmap_atomic(__addr);                                \
 267 } while (0)
 268
 269 /**
 270  * kunmap_local - Unmap a page mapped via kmap_local_page().
 271  * @__addr: An address within the page mapped
 272  *
 273  * @__addr can be any address within the mapped page.  Commonly it is the
 274  * address return from kmap_local_page(), but it can also include offsets.
 275  *
 276  * Unmapping should be done in the reverse order of the mapping.  See
 277  * kmap_local_page() for details.
 278  */
 279 #define kunmap_local(__addr)                                    \
 280 do {                                                            \
 281         BUILD_BUG_ON(__same_type((__addr), struct page *));     \
 282         __kunmap_local(__addr);                                 \
 283 } while (0)
 284
 285 #endif