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_pop(void)
  92 {
  93         int idx = --__get_cpu_var(__kmap_atomic_idx);
  94 #ifdef CONFIG_DEBUG_HIGHMEM
  95         BUG_ON(idx < 0);
  96 #endif
  97         return idx;
  98 }
  99
 100 #endif
 101
 102 /*
 103  * Make both: kmap_atomic(page, idx) and kmap_atomic(page) work.
 104  */
 105 #define kmap_atomic(page, args...) __kmap_atomic(page)
 106
 107 /*
 108  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
 109  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
 110  */
 111 #define kunmap_atomic(addr, args...)                            \
 112 do {                                                            \
 113         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 114         __kunmap_atomic(addr);                                  \
 115 } while (0)
 116
 117 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 118 #ifndef clear_user_highpage
 119 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 120 {
 121         void *addr = kmap_atomic(page, KM_USER0);
 122         clear_user_page(addr, vaddr, page);
 123         kunmap_atomic(addr, KM_USER0);
 124 }
 125 #endif
 126
 127 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 128 /**
 129  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 130  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 131  * @vma: The VMA the page is to be allocated for
 132  * @vaddr: The virtual address the page will be inserted into
 133  *
 134  * This function will allocate a page for a VMA but the caller is expected
 135  * to specify via movableflags whether the page will be movable in the
 136  * future or not
 137  *
 138  * An architecture may override this function by defining
 139  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 140  * implementation.
 141  */
 142 static inline struct page *
 143 __alloc_zeroed_user_highpage(gfp_t movableflags,
 144                         struct vm_area_struct *vma,
 145                         unsigned long vaddr)
 146 {
 147         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 148                         vma, vaddr);
 149
 150         if (page)
 151                 clear_user_highpage(page, vaddr);
 152
 153         return page;
 154 }
 155 #endif
 156
 157 /**
 158  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 159  * @vma: The VMA the page is to be allocated for
 160  * @vaddr: The virtual address the page will be inserted into
 161  *
 162  * This function will allocate a page for a VMA that the caller knows will
 163  * be able to migrate in the future using move_pages() or reclaimed
 164  */
 165 static inline struct page *
 166 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 167                                         unsigned long vaddr)
 168 {
 169         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 170 }
 171
 172 static inline void clear_highpage(struct page *page)
 173 {
 174         void *kaddr = kmap_atomic(page, KM_USER0);
 175         clear_page(kaddr);
 176         kunmap_atomic(kaddr, KM_USER0);
 177 }
 178
 179 static inline void zero_user_segments(struct page *page,
 180         unsigned start1, unsigned end1,
 181         unsigned start2, unsigned end2)
 182 {
 183         void *kaddr = kmap_atomic(page, KM_USER0);
 184
 185         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 186
 187         if (end1 > start1)
 188                 memset(kaddr + start1, 0, end1 - start1);
 189
 190         if (end2 > start2)
 191                 memset(kaddr + start2, 0, end2 - start2);
 192
 193         kunmap_atomic(kaddr, KM_USER0);
 194         flush_dcache_page(page);
 195 }
 196
 197 static inline void zero_user_segment(struct page *page,
 198         unsigned start, unsigned end)
 199 {
 200         zero_user_segments(page, start, end, 0, 0);
 201 }
 202
 203 static inline void zero_user(struct page *page,
 204         unsigned start, unsigned size)
 205 {
 206         zero_user_segments(page, start, start + size, 0, 0);
 207 }
 208
 209 static inline void __deprecated memclear_highpage_flush(struct page *page,
 210                         unsigned int offset, unsigned int size)
 211 {
 212         zero_user(page, offset, size);
 213 }
 214
 215 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 216
 217 static inline void copy_user_highpage(struct page *to, struct page *from,
 218         unsigned long vaddr, struct vm_area_struct *vma)
 219 {
 220         char *vfrom, *vto;
 221
 222         vfrom = kmap_atomic(from, KM_USER0);
 223         vto = kmap_atomic(to, KM_USER1);
 224         copy_user_page(vto, vfrom, vaddr, to);
 225         kunmap_atomic(vto, KM_USER1);
 226         kunmap_atomic(vfrom, KM_USER0);
 227 }
 228
 229 #endif
 230
 231 static inline void copy_highpage(struct page *to, struct page *from)
 232 {
 233         char *vfrom, *vto;
 234
 235         vfrom = kmap_atomic(from, KM_USER0);
 236         vto = kmap_atomic(to, KM_USER1);
 237         copy_page(vto, vfrom);
 238         kunmap_atomic(vto, KM_USER1);
 239         kunmap_atomic(vfrom, KM_USER0);
 240 }
 241
 242 #endif /* _LINUX_HIGHMEM_H */