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/mm.h>
   7 #include <linux/uaccess.h>
   8
   9 #include <asm/cacheflush.h>
  10
  11 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  12 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
  13 {
  14 }
  15 #endif
  16
  17 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  18 static inline void flush_kernel_dcache_page(struct page *page)
  19 {
  20 }
  21 static inline void flush_kernel_vmap_range(void *vaddr, int size)
  22 {
  23 }
  24 static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
  25 {
  26 }
  27 #endif
  28
  29 #include <asm/kmap_types.h>
  30
  31 #ifdef CONFIG_HIGHMEM
  32 #include <asm/highmem.h>
  33
  34 /* declarations for linux/mm/highmem.c */
  35 unsigned int nr_free_highpages(void);
  36 extern unsigned long totalhigh_pages;
  37
  38 void kmap_flush_unused(void);
  39
  40 #else /* CONFIG_HIGHMEM */
  41
  42 static inline unsigned int nr_free_highpages(void) { return 0; }
  43
  44 #define totalhigh_pages 0UL
  45
  46 #ifndef ARCH_HAS_KMAP
  47 static inline void *kmap(struct page *page)
  48 {
  49         might_sleep();
  50         return page_address(page);
  51 }
  52
  53 static inline void kunmap(struct page *page)
  54 {
  55 }
  56
  57 static inline void *__kmap_atomic(struct page *page)
  58 {
  59         pagefault_disable();
  60         return page_address(page);
  61 }
  62 #define kmap_atomic_prot(page, prot)    __kmap_atomic(page)
  63
  64 static inline void __kunmap_atomic(void *addr)
  65 {
  66         pagefault_enable();
  67 }
  68
  69 #define kmap_atomic_pfn(pfn)    kmap_atomic(pfn_to_page(pfn))
  70 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  71
  72 #define kmap_flush_unused()     do {} while(0)
  73 #endif
  74
  75 #endif /* CONFIG_HIGHMEM */
  76
  77 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
  78
  79 DECLARE_PER_CPU(int, __kmap_atomic_idx);
  80
  81 static inline int kmap_atomic_idx_push(void)
  82 {
  83         int idx = __get_cpu_var(__kmap_atomic_idx)++;
  84 #ifdef CONFIG_DEBUG_HIGHMEM
  85         WARN_ON_ONCE(in_irq() && !irqs_disabled());
  86         BUG_ON(idx > KM_TYPE_NR);
  87 #endif
  88         return idx;
  89 }
  90
  91 static inline int kmap_atomic_idx(void)
  92 {
  93         return __get_cpu_var(__kmap_atomic_idx) - 1;
  94 }
  95
  96 static inline int kmap_atomic_idx_pop(void)
  97 {
  98         int idx = --__get_cpu_var(__kmap_atomic_idx);
  99 #ifdef CONFIG_DEBUG_HIGHMEM
 100         BUG_ON(idx < 0);
 101 #endif
 102         return idx;
 103 }
 104
 105 #endif
 106
 107 /*
 108  * Make both: kmap_atomic(page, idx) and kmap_atomic(page) work.
 109  */
 110 #define kmap_atomic(page, args...) __kmap_atomic(page)
 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, args...)                            \
 117 do {                                                            \
 118         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 119         __kunmap_atomic(addr);                                  \
 120 } while (0)
 121
 122 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 123 #ifndef clear_user_highpage
 124 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 125 {
 126         void *addr = kmap_atomic(page, KM_USER0);
 127         clear_user_page(addr, vaddr, page);
 128         kunmap_atomic(addr, KM_USER0);
 129 }
 130 #endif
 131
 132 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 133 /**
 134  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 135  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 136  * @vma: The VMA the page is to be allocated for
 137  * @vaddr: The virtual address the page will be inserted into
 138  *
 139  * This function will allocate a page for a VMA but the caller is expected
 140  * to specify via movableflags whether the page will be movable in the
 141  * future or not
 142  *
 143  * An architecture may override this function by defining
 144  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 145  * implementation.
 146  */
 147 static inline struct page *
 148 __alloc_zeroed_user_highpage(gfp_t movableflags,
 149                         struct vm_area_struct *vma,
 150                         unsigned long vaddr)
 151 {
 152         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 153                         vma, vaddr);
 154
 155         if (page)
 156                 clear_user_highpage(page, vaddr);
 157
 158         return page;
 159 }
 160 #endif
 161
 162 /**
 163  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 164  * @vma: The VMA the page is to be allocated for
 165  * @vaddr: The virtual address the page will be inserted into
 166  *
 167  * This function will allocate a page for a VMA that the caller knows will
 168  * be able to migrate in the future using move_pages() or reclaimed
 169  */
 170 static inline struct page *
 171 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 172                                         unsigned long vaddr)
 173 {
 174         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 175 }
 176
 177 static inline void clear_highpage(struct page *page)
 178 {
 179         void *kaddr = kmap_atomic(page, KM_USER0);
 180         clear_page(kaddr);
 181         kunmap_atomic(kaddr, KM_USER0);
 182 }
 183
 184 static inline void zero_user_segments(struct page *page,
 185         unsigned start1, unsigned end1,
 186         unsigned start2, unsigned end2)
 187 {
 188         void *kaddr = kmap_atomic(page, KM_USER0);
 189
 190         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 191
 192         if (end1 > start1)
 193                 memset(kaddr + start1, 0, end1 - start1);
 194
 195         if (end2 > start2)
 196                 memset(kaddr + start2, 0, end2 - start2);
 197
 198         kunmap_atomic(kaddr, KM_USER0);
 199         flush_dcache_page(page);
 200 }
 201
 202 static inline void zero_user_segment(struct page *page,
 203         unsigned start, unsigned end)
 204 {
 205         zero_user_segments(page, start, end, 0, 0);
 206 }
 207
 208 static inline void zero_user(struct page *page,
 209         unsigned start, unsigned size)
 210 {
 211         zero_user_segments(page, start, start + size, 0, 0);
 212 }
 213
 214 static inline void __deprecated memclear_highpage_flush(struct page *page,
 215                         unsigned int offset, unsigned int size)
 216 {
 217         zero_user(page, offset, size);
 218 }
 219
 220 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 221
 222 static inline void copy_user_highpage(struct page *to, struct page *from,
 223         unsigned long vaddr, struct vm_area_struct *vma)
 224 {
 225         char *vfrom, *vto;
 226
 227         vfrom = kmap_atomic(from, KM_USER0);
 228         vto = kmap_atomic(to, KM_USER1);
 229         copy_user_page(vto, vfrom, vaddr, to);
 230         kunmap_atomic(vto, KM_USER1);
 231         kunmap_atomic(vfrom, KM_USER0);
 232 }
 233
 234 #endif
 235
 236 static inline void copy_highpage(struct page *to, struct page *from)
 237 {
 238         char *vfrom, *vto;
 239
 240         vfrom = kmap_atomic(from, KM_USER0);
 241         vto = kmap_atomic(to, KM_USER1);
 242         copy_page(vto, vfrom);
 243         kunmap_atomic(vto, KM_USER1);
 244         kunmap_atomic(vfrom, KM_USER0);
 245 }
 246
 247 #endif /* _LINUX_HIGHMEM_H */