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 #include <linux/hardirq.h>
   9
  10 #include <asm/cacheflush.h>
  11
  12 #ifndef ARCH_HAS_FLUSH_ANON_PAGE
  13 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
  14 {
  15 }
  16 #endif
  17
  18 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
  19 static inline void flush_kernel_dcache_page(struct page *page)
  20 {
  21 }
  22 static inline void flush_kernel_vmap_range(void *vaddr, int size)
  23 {
  24 }
  25 static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
  26 {
  27 }
  28 #endif
  29
  30 #include <asm/kmap_types.h>
  31
  32 #ifdef CONFIG_HIGHMEM
  33 #include <asm/highmem.h>
  34
  35 /* declarations for linux/mm/highmem.c */
  36 unsigned int nr_free_highpages(void);
  37 extern unsigned long totalhigh_pages;
  38
  39 void kmap_flush_unused(void);
  40
  41 #else /* CONFIG_HIGHMEM */
  42
  43 static inline unsigned int nr_free_highpages(void) { return 0; }
  44
  45 #define totalhigh_pages 0UL
  46
  47 #ifndef ARCH_HAS_KMAP
  48 static inline void *kmap(struct page *page)
  49 {
  50         might_sleep();
  51         return page_address(page);
  52 }
  53
  54 static inline void kunmap(struct page *page)
  55 {
  56 }
  57
  58 static inline void *__kmap_atomic(struct page *page)
  59 {
  60         pagefault_disable();
  61         return page_address(page);
  62 }
  63 #define kmap_atomic_prot(page, prot)    __kmap_atomic(page)
  64
  65 static inline void __kunmap_atomic(void *addr)
  66 {
  67         pagefault_enable();
  68 }
  69
  70 #define kmap_atomic_pfn(pfn)    kmap_atomic(pfn_to_page(pfn))
  71 #define kmap_atomic_to_page(ptr)        virt_to_page(ptr)
  72
  73 #define kmap_flush_unused()     do {} while(0)
  74 #endif
  75
  76 #endif /* CONFIG_HIGHMEM */
  77
  78 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
  79
  80 DECLARE_PER_CPU(int, __kmap_atomic_idx);
  81
  82 static inline int kmap_atomic_idx_push(void)
  83 {
  84         int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
  85
  86 #ifdef CONFIG_DEBUG_HIGHMEM
  87         WARN_ON_ONCE(in_irq() && !irqs_disabled());
  88         BUG_ON(idx > KM_TYPE_NR);
  89 #endif
  90         return idx;
  91 }
  92
  93 static inline int kmap_atomic_idx(void)
  94 {
  95         return __this_cpu_read(__kmap_atomic_idx) - 1;
  96 }
  97
  98 static inline void kmap_atomic_idx_pop(void)
  99 {
 100 #ifdef CONFIG_DEBUG_HIGHMEM
 101         int idx = __this_cpu_dec_return(__kmap_atomic_idx);
 102
 103         BUG_ON(idx < 0);
 104 #else
 105         __this_cpu_dec(__kmap_atomic_idx);
 106 #endif
 107 }
 108
 109 #endif
 110
 111 /*
 112  * Make both: kmap_atomic(page, idx) and kmap_atomic(page) work.
 113  */
 114 #define kmap_atomic(page, args...) __kmap_atomic(page)
 115
 116 /*
 117  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
 118  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
 119  */
 120 #define kunmap_atomic(addr, args...)                            \
 121 do {                                                            \
 122         BUILD_BUG_ON(__same_type((addr), struct page *));       \
 123         __kunmap_atomic(addr);                                  \
 124 } while (0)
 125
 126 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
 127 #ifndef clear_user_highpage
 128 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
 129 {
 130         void *addr = kmap_atomic(page, KM_USER0);
 131         clear_user_page(addr, vaddr, page);
 132         kunmap_atomic(addr, KM_USER0);
 133 }
 134 #endif
 135
 136 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
 137 /**
 138  * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
 139  * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
 140  * @vma: The VMA the page is to be allocated for
 141  * @vaddr: The virtual address the page will be inserted into
 142  *
 143  * This function will allocate a page for a VMA but the caller is expected
 144  * to specify via movableflags whether the page will be movable in the
 145  * future or not
 146  *
 147  * An architecture may override this function by defining
 148  * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
 149  * implementation.
 150  */
 151 static inline struct page *
 152 __alloc_zeroed_user_highpage(gfp_t movableflags,
 153                         struct vm_area_struct *vma,
 154                         unsigned long vaddr)
 155 {
 156         struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
 157                         vma, vaddr);
 158
 159         if (page)
 160                 clear_user_highpage(page, vaddr);
 161
 162         return page;
 163 }
 164 #endif
 165
 166 /**
 167  * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
 168  * @vma: The VMA the page is to be allocated for
 169  * @vaddr: The virtual address the page will be inserted into
 170  *
 171  * This function will allocate a page for a VMA that the caller knows will
 172  * be able to migrate in the future using move_pages() or reclaimed
 173  */
 174 static inline struct page *
 175 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
 176                                         unsigned long vaddr)
 177 {
 178         return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
 179 }
 180
 181 static inline void clear_highpage(struct page *page)
 182 {
 183         void *kaddr = kmap_atomic(page, KM_USER0);
 184         clear_page(kaddr);
 185         kunmap_atomic(kaddr, KM_USER0);
 186 }
 187
 188 static inline void zero_user_segments(struct page *page,
 189         unsigned start1, unsigned end1,
 190         unsigned start2, unsigned end2)
 191 {
 192         void *kaddr = kmap_atomic(page, KM_USER0);
 193
 194         BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
 195
 196         if (end1 > start1)
 197                 memset(kaddr + start1, 0, end1 - start1);
 198
 199         if (end2 > start2)
 200                 memset(kaddr + start2, 0, end2 - start2);
 201
 202         kunmap_atomic(kaddr, KM_USER0);
 203         flush_dcache_page(page);
 204 }
 205
 206 static inline void zero_user_segment(struct page *page,
 207         unsigned start, unsigned end)
 208 {
 209         zero_user_segments(page, start, end, 0, 0);
 210 }
 211
 212 static inline void zero_user(struct page *page,
 213         unsigned start, unsigned size)
 214 {
 215         zero_user_segments(page, start, start + size, 0, 0);
 216 }
 217
 218 static inline void __deprecated memclear_highpage_flush(struct page *page,
 219                         unsigned int offset, unsigned int size)
 220 {
 221         zero_user(page, offset, size);
 222 }
 223
 224 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 225
 226 static inline void copy_user_highpage(struct page *to, struct page *from,
 227         unsigned long vaddr, struct vm_area_struct *vma)
 228 {
 229         char *vfrom, *vto;
 230
 231         vfrom = kmap_atomic(from, KM_USER0);
 232         vto = kmap_atomic(to, KM_USER1);
 233         copy_user_page(vto, vfrom, vaddr, to);
 234         kunmap_atomic(vto, KM_USER1);
 235         kunmap_atomic(vfrom, KM_USER0);
 236 }
 237
 238 #endif
 239
 240 static inline void copy_highpage(struct page *to, struct page *from)
 241 {
 242         char *vfrom, *vto;
 243
 244         vfrom = kmap_atomic(from, KM_USER0);
 245         vto = kmap_atomic(to, KM_USER1);
 246         copy_page(vto, vfrom);
 247         kunmap_atomic(vto, KM_USER1);
 248         kunmap_atomic(vfrom, KM_USER0);
 249 }
 250
 251 #endif /* _LINUX_HIGHMEM_H */