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