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         preempt_disable();
  69         pagefault_disable();
  70         return page_address(page);
  71 }
  72 #define kmap_atomic_prot(page, prot)    kmap_atomic(page)
  73
  74 static inline void __kunmap_atomic(void *addr)
  75 {
  76         pagefault_enable();
  77         preempt_enable();
  78 }
  79
  80 #define kmap_atomic_pfn(pfn)    kmap_atomic(pfn_to_page(pfn))
  81
  82 #define kmap_flush_unused()     do {} while(0)
  83 #endif
  84
  85 #endif /* CONFIG_HIGHMEM */
  86
  87 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
  88
  89 DECLARE_PER_CPU(int, __kmap_atomic_idx);
  90
  91 static inline int kmap_atomic_idx_push(void)
  92 {
  93         int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
  94
  95 #ifdef CONFIG_DEBUG_HIGHMEM
  96         WARN_ON_ONCE(in_irq() && !irqs_disabled());
  97         BUG_ON(idx >= KM_TYPE_NR);
  98 #endif
  99         return idx;
 100 }
 101
 102 static inline int kmap_atomic_idx(void)
 103 {
 104         return __this_cpu_read(__kmap_atomic_idx) - 1;
 105 }
 106
 107 static inline void kmap_atomic_idx_pop(void)
 108 {
 109 #ifdef CONFIG_DEBUG_HIGHMEM
 110         int idx = __this_cpu_dec_return(__kmap_atomic_idx);
 111
 112         BUG_ON(idx < 0);
 113 #else
 114         __this_cpu_dec(__kmap_atomic_idx);
 115 #endif
 116 }
 117
 118 #endif
 119
 120 /*
 121  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
 122  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
 123  */
 124 #define kunmap_atomic(addr)                                     \
 125 do {                                                            \
 126         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 127         __kunmap_atomic(addr);                                  \
 128 } while (0)
 129
 130
 131 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 132 #ifndef clear_user_highpage
 133 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 134 {
 135         void *addr = kmap_atomic(page);
 136         clear_user_page(addr, vaddr, page);
 137         kunmap_atomic(addr);
 138 }
 139 #endif
 140
 141 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 142 /**
 143  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 144  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 145  * @vma: The VMA the page is to be allocated for
 146  * @vaddr: The virtual address the page will be inserted into
 147  *
 148  * This function will allocate a page for a VMA but the caller is expected
 149  * to specify via movableflags whether the page will be movable in the
 150  * future or not
 151  *
 152  * An architecture may override this function by defining
 153  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 154  * implementation.
 155  */
 156 static inline struct page *
 157 __alloc_zeroed_user_highpage(gfp_t movableflags,
 158                         struct vm_area_struct *vma,
 159                         unsigned long vaddr)
 160 {
 161         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 162                         vma, vaddr);
 163
 164         if (page)
 165                 clear_user_highpage(page, vaddr);
 166
 167         return page;
 168 }
 169 #endif
 170
 171 /**
 172  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 173  * @vma: The VMA the page is to be allocated for
 174  * @vaddr: The virtual address the page will be inserted into
 175  *
 176  * This function will allocate a page for a VMA that the caller knows will
 177  * be able to migrate in the future using move_pages() or reclaimed
 178  */
 179 static inline struct page *
 180 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 181                                         unsigned long vaddr)
 182 {
 183         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 184 }
 185
 186 static inline void clear_highpage(struct page *page)
 187 {
 188         void *kaddr = kmap_atomic(page);
 189         clear_page(kaddr);
 190         kunmap_atomic(kaddr);
 191 }
 192
 193 static inline void zero_user_segments(struct page *page,
 194         unsigned start1, unsigned end1,
 195         unsigned start2, unsigned end2)
 196 {
 197         void *kaddr = kmap_atomic(page);
 198
 199         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 200
 201         if (end1 > start1)
 202                 memset(kaddr + start1, 0, end1 - start1);
 203
 204         if (end2 > start2)
 205                 memset(kaddr + start2, 0, end2 - start2);
 206
 207         kunmap_atomic(kaddr);
 208         flush_dcache_page(page);
 209 }
 210
 211 static inline void zero_user_segment(struct page *page,
 212         unsigned start, unsigned end)
 213 {
 214         zero_user_segments(page, start, end, 0, 0);
 215 }
 216
 217 static inline void zero_user(struct page *page,
 218         unsigned start, unsigned size)
 219 {
 220         zero_user_segments(page, start, start + size, 0, 0);
 221 }
 222
 223 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 224
 225 static inline void copy_user_highpage(struct page *to, struct page *from,
 226         unsigned long vaddr, struct vm_area_struct *vma)
 227 {
 228         char *vfrom, *vto;
 229
 230         vfrom = kmap_atomic(from);
 231         vto = kmap_atomic(to);
 232         copy_user_page(vto, vfrom, vaddr, to);
 233         kunmap_atomic(vto);
 234         kunmap_atomic(vfrom);
 235 }
 236
 237 #endif
 238
 239 static inline void copy_highpage(struct page *to, struct page *from)
 240 {
 241         char *vfrom, *vto;
 242
 243         vfrom = kmap_atomic(from);
 244         vto = kmap_atomic(to);
 245         copy_page(vto, vfrom);
 246         kunmap_atomic(vto);
 247         kunmap_atomic(vfrom);
 248 }
 249
 250 #endif /* _LINUX_HIGHMEM_H */