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(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(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(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 int __nr_free_highpages(void);
 135 extern atomic_long_t _totalhigh_pages;
 136
 137 static inline unsigned int nr_free_highpages(void)
 138 {
 139         return __nr_free_highpages();
 140 }
 141
 142 static inline unsigned long totalhigh_pages(void)
 143 {
 144         return (unsigned long)atomic_long_read(&_totalhigh_pages);
 145 }
 146
 147 static inline void totalhigh_pages_add(long count)
 148 {
 149         atomic_long_add(count, &_totalhigh_pages);
 150 }
 151
 152 static inline bool is_kmap_addr(const void *x)
 153 {
 154         unsigned long addr = (unsigned long)x;
 155         return addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP);
 156 }
 157 #else /* CONFIG_HIGHMEM */
 158
 159 static inline struct page *kmap_to_page(void *addr)
 160 {
 161         return virt_to_page(addr);
 162 }
 163
 164 static inline void *kmap(struct page *page)
 165 {
 166         might_sleep();
 167         return page_address(page);
 168 }
 169
 170 static inline void kunmap_high(struct page *page) { }
 171 static inline void kmap_flush_unused(void) { }
 172
 173 static inline void kunmap(struct page *page)
 174 {
 175 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
 176         kunmap_flush_on_unmap(page_address(page));
 177 #endif
 178 }
 179
 180 static inline void *kmap_local_page(struct page *page)
 181 {
 182         return page_address(page);
 183 }
 184
 185 static inline void *kmap_local_folio(struct folio *folio, size_t offset)
 186 {
 187         return page_address(&folio->page) + offset;
 188 }
 189
 190 static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
 191 {
 192         return kmap_local_page(page);
 193 }
 194
 195 static inline void *kmap_local_pfn(unsigned long pfn)
 196 {
 197         return kmap_local_page(pfn_to_page(pfn));
 198 }
 199
 200 static inline void __kunmap_local(void *addr)
 201 {
 202 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
 203         kunmap_flush_on_unmap(addr);
 204 #endif
 205 }
 206
 207 static inline void *kmap_atomic(struct page *page)
 208 {
 209         if (IS_ENABLED(CONFIG_PREEMPT_RT))
 210                 migrate_disable();
 211         else
 212                 preempt_disable();
 213         pagefault_disable();
 214         return page_address(page);
 215 }
 216
 217 static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 218 {
 219         return kmap_atomic(page);
 220 }
 221
 222 static inline void *kmap_atomic_pfn(unsigned long pfn)
 223 {
 224         return kmap_atomic(pfn_to_page(pfn));
 225 }
 226
 227 static inline void __kunmap_atomic(void *addr)
 228 {
 229 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
 230         kunmap_flush_on_unmap(addr);
 231 #endif
 232         pagefault_enable();
 233         if (IS_ENABLED(CONFIG_PREEMPT_RT))
 234                 migrate_enable();
 235         else
 236                 preempt_enable();
 237 }
 238
 239 static inline unsigned int nr_free_highpages(void) { return 0; }
 240 static inline unsigned long totalhigh_pages(void) { return 0UL; }
 241
 242 static inline bool is_kmap_addr(const void *x)
 243 {
 244         return false;
 245 }
 246
 247 #endif /* CONFIG_HIGHMEM */
 248
 249 /**
 250  * kunmap_atomic - Unmap the virtual address mapped by kmap_atomic() - deprecated!
 251  * @__addr:       Virtual address to be unmapped
 252  *
 253  * Unmaps an address previously mapped by kmap_atomic() and re-enables
 254  * pagefaults. Depending on PREEMP_RT configuration, re-enables also
 255  * migration and preemption. Users should not count on these side effects.
 256  *
 257  * Mappings should be unmapped in the reverse order that they were mapped.
 258  * See kmap_local_page() for details on nesting.
 259  *
 260  * @__addr can be any address within the mapped page, so there is no need
 261  * to subtract any offset that has been added. In contrast to kunmap(),
 262  * this function takes the address returned from kmap_atomic(), not the
 263  * page passed to it. The compiler will warn you if you pass the page.
 264  */
 265 #define kunmap_atomic(__addr)                                   \
 266 do {                                                            \
 267         BUILD_BUG_ON(__same_type((__addr), struct page *));     \
 268         __kunmap_atomic(__addr);                                \
 269 } while (0)
 270
 271 /**
 272  * kunmap_local - Unmap a page mapped via kmap_local_page().
 273  * @__addr: An address within the page mapped
 274  *
 275  * @__addr can be any address within the mapped page.  Commonly it is the
 276  * address return from kmap_local_page(), but it can also include offsets.
 277  *
 278  * Unmapping should be done in the reverse order of the mapping.  See
 279  * kmap_local_page() for details.
 280  */
 281 #define kunmap_local(__addr)                                    \
 282 do {                                                            \
 283         BUILD_BUG_ON(__same_type((__addr), struct page *));     \
 284         __kunmap_local(__addr);                                 \
 285 } while (0)
 286
 287 #endif