include/linux/highmem.h

   1 #ifndef _LINUX_HIGHMEM_H
   2 #define _LINUX_HIGHMEM_H
   3
   4 #include <linux/fs.h>
   5 #include <linux/kernel.h>
   6 #include <linux/bug.h>
   7 #include <linux/mm.h>
   8 #include <linux/uaccess.h>
   9 #include <linux/hardirq.h>
  10
  11 #include <asm/cacheflush.h>
  12
  13 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  14 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
  15 {
  16 }
  17 #endif
  18
  19 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  20 static inline void flush_kernel_dcache_page(struct page *page)
  21 {
  22 }
  23 static inline void flush_kernel_vmap_range(void *vaddr, int size)
  24 {
  25 }
  26 static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
  27 {
  28 }
  29 #endif
  30
  31 #include <asm/kmap_types.h>
  32
  33 #ifdef CONFIG_HIGHMEM
  34 #include <asm/highmem.h>
  35
  36 /* declarations for linux/mm/highmem.c */
  37 unsigned int nr_free_highpages(void);
  38 extern unsigned long totalhigh_pages;
  39
  40 void kmap_flush_unused(void);
  41
  42 struct page *kmap_to_page(void *addr);
  43
  44 #else /* CONFIG_HIGHMEM */
  45
  46 static inline unsigned int nr_free_highpages(void) { return 0; }
  47
  48 static inline struct page *kmap_to_page(void *addr)
  49 {
  50         return virt_to_page(addr);
  51 }
  52
  53 #define totalhigh_pages 0UL
  54
  55 #ifndef ARCH_HAS_KMAP
  56 static inline void *kmap(struct page *page)
  57 {
  58         might_sleep();
  59         return page_address(page);
  60 }
  61
  62 static inline void kunmap(struct page *page)
  63 {
  64 }
  65
  66 static inline void *kmap_atomic(struct page *page)
  67 {
  68         pagefault_disable();
  69         return page_address(page);
  70 }
  71 #define kmap_atomic_prot(page, prot)    kmap_atomic(page)
  72
  73 static inline void __kunmap_atomic(void *addr)
  74 {
  75         pagefault_enable();
  76 }
  77
  78 #define kmap_atomic_pfn(pfn)    kmap_atomic(pfn_to_page(pfn))
  79 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  80
  81 #define kmap_flush_unused()     do {} while(0)
  82 #endif
  83
  84 #endif /* CONFIG_HIGHMEM */
  85
  86 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
  87
  88 DECLARE_PER_CPU(int, __kmap_atomic_idx);
  89
  90 static inline int kmap_atomic_idx_push(void)
  91 {
  92         int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
  93
  94 #ifdef CONFIG_DEBUG_HIGHMEM
  95         WARN_ON_ONCE(in_irq() && !irqs_disabled());
  96         BUG_ON(idx > KM_TYPE_NR);
  97 #endif
  98         return idx;
  99 }
 100
 101 static inline int kmap_atomic_idx(void)
 102 {
 103         return __this_cpu_read(__kmap_atomic_idx) - 1;
 104 }
 105
 106 static inline void kmap_atomic_idx_pop(void)
 107 {
 108 #ifdef CONFIG_DEBUG_HIGHMEM
 109         int idx = __this_cpu_dec_return(__kmap_atomic_idx);
 110
 111         BUG_ON(idx < 0);
 112 #else
 113         __this_cpu_dec(__kmap_atomic_idx);
 114 #endif
 115 }
 116
 117 #endif
 118
 119 /*
 120  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
 121  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
 122  */
 123 #define kunmap_atomic(addr)                                     \
 124 do {                                                            \
 125         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 126         __kunmap_atomic(addr);                                  \
 127 } while (0)
 128
 129
 130 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 131 #ifndef clear_user_highpage
 132 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 133 {
 134         void *addr = kmap_atomic(page);
 135         clear_user_page(addr, vaddr, page);
 136         kunmap_atomic(addr);
 137 }
 138 #endif
 139
 140 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 141 /**
 142  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 143  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 144  * @vma: The VMA the page is to be allocated for
 145  * @vaddr: The virtual address the page will be inserted into
 146  *
 147  * This function will allocate a page for a VMA but the caller is expected
 148  * to specify via movableflags whether the page will be movable in the
 149  * future or not
 150  *
 151  * An architecture may override this function by defining
 152  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 153  * implementation.
 154  */
 155 static inline struct page *
 156 __alloc_zeroed_user_highpage(gfp_t movableflags,
 157                         struct vm_area_struct *vma,
 158                         unsigned long vaddr)
 159 {
 160         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 161                         vma, vaddr);
 162
 163         if (page)
 164                 clear_user_highpage(page, vaddr);
 165
 166         return page;
 167 }
 168 #endif
 169
 170 /**
 171  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 172  * @vma: The VMA the page is to be allocated for
 173  * @vaddr: The virtual address the page will be inserted into
 174  *
 175  * This function will allocate a page for a VMA that the caller knows will
 176  * be able to migrate in the future using move_pages() or reclaimed
 177  */
 178 static inline struct page *
 179 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 180                                         unsigned long vaddr)
 181 {
 182         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 183 }
 184
 185 static inline void clear_highpage(struct page *page)
 186 {
 187         void *kaddr = kmap_atomic(page);
 188         clear_page(kaddr);
 189         kunmap_atomic(kaddr);
 190 }
 191
 192 static inline void zero_user_segments(struct page *page,
 193         unsigned start1, unsigned end1,
 194         unsigned start2, unsigned end2)
 195 {
 196         void *kaddr = kmap_atomic(page);
 197
 198         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 199
 200         if (end1 > start1)
 201                 memset(kaddr + start1, 0, end1 - start1);
 202
 203         if (end2 > start2)
 204                 memset(kaddr + start2, 0, end2 - start2);
 205
 206         kunmap_atomic(kaddr);
 207         flush_dcache_page(page);
 208 }
 209
 210 static inline void zero_user_segment(struct page *page,
 211         unsigned start, unsigned end)
 212 {
 213         zero_user_segments(page, start, end, 0, 0);
 214 }
 215
 216 static inline void zero_user(struct page *page,
 217         unsigned start, unsigned size)
 218 {
 219         zero_user_segments(page, start, start + size, 0, 0);
 220 }
 221
 222 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 223
 224 static inline void copy_user_highpage(struct page *to, struct page *from,
 225         unsigned long vaddr, struct vm_area_struct *vma)
 226 {
 227         char *vfrom, *vto;
 228
 229         vfrom = kmap_atomic(from);
 230         vto = kmap_atomic(to);
 231         copy_user_page(vto, vfrom, vaddr, to);
 232         kunmap_atomic(vto);
 233         kunmap_atomic(vfrom);
 234 }
 235
 236 #endif
 237
 238 static inline void copy_highpage(struct page *to, struct page *from)
 239 {
 240         char *vfrom, *vto;
 241
 242         vfrom = kmap_atomic(from);
 243         vto = kmap_atomic(to);
 244         copy_page(vto, vfrom);
 245         kunmap_atomic(vto);
 246         kunmap_atomic(vfrom);
 247 }
 248
 249 #endif /* _LINUX_HIGHMEM_H */