1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_HIGHMEM_H 3 #define _LINUX_HIGHMEM_H 4 5 #include <linux/fs.h> 6 #include <linux/kernel.h> 7 #include <linux/bug.h> 8 #include <linux/mm.h> 9 #include <linux/uaccess.h> 10 #include <linux/hardirq.h> 11 12 #include <asm/cacheflush.h> 13 14 #ifndef ARCH_HAS_FLUSH_ANON_PAGE 15 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr) 16 { 17 } 18 #endif 19 20 #ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE 21 static inline void flush_kernel_dcache_page(struct page *page) 22 { 23 } 24 static inline void flush_kernel_vmap_range(void *vaddr, int size) 25 { 26 } 27 static inline void invalidate_kernel_vmap_range(void *vaddr, int size) 28 { 29 } 30 #endif 31 32 #include <asm/kmap_types.h> 33 34 #ifdef CONFIG_HIGHMEM 35 #include <asm/highmem.h> 36 37 /* declarations for linux/mm/highmem.c */ 38 unsigned int nr_free_highpages(void); 39 extern unsigned long totalhigh_pages; 40 41 void kmap_flush_unused(void); 42 43 struct page *kmap_to_page(void *addr); 44 45 #else /* CONFIG_HIGHMEM */ 46 47 static inline unsigned int nr_free_highpages(void) { return 0; } 48 49 static inline struct page *kmap_to_page(void *addr) 50 { 51 return virt_to_page(addr); 52 } 53 54 #define totalhigh_pages 0UL 55 56 #ifndef ARCH_HAS_KMAP 57 static inline void *kmap(struct page *page) 58 { 59 might_sleep(); 60 return page_address(page); 61 } 62 63 static inline void kunmap(struct page *page) 64 { 65 } 66 67 static inline void *kmap_atomic(struct page *page) 68 { 69 preempt_disable(); 70 pagefault_disable(); 71 return page_address(page); 72 } 73 #define kmap_atomic_prot(page, prot) kmap_atomic(page) 74 75 static inline void __kunmap_atomic(void *addr) 76 { 77 pagefault_enable(); 78 preempt_enable(); 79 } 80 81 #define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn)) 82 83 #define kmap_flush_unused() do {} while(0) 84 #endif 85 86 #endif /* CONFIG_HIGHMEM */ 87 88 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) 89 90 DECLARE_PER_CPU(int, __kmap_atomic_idx); 91 92 static inline int kmap_atomic_idx_push(void) 93 { 94 int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1; 95 96 #ifdef CONFIG_DEBUG_HIGHMEM 97 WARN_ON_ONCE(in_irq() && !irqs_disabled()); 98 BUG_ON(idx >= KM_TYPE_NR); 99 #endif 100 return idx; 101 } 102 103 static inline int kmap_atomic_idx(void) 104 { 105 return __this_cpu_read(__kmap_atomic_idx) - 1; 106 } 107 108 static inline void kmap_atomic_idx_pop(void) 109 { 110 #ifdef CONFIG_DEBUG_HIGHMEM 111 int idx = __this_cpu_dec_return(__kmap_atomic_idx); 112 113 BUG_ON(idx < 0); 114 #else 115 __this_cpu_dec(__kmap_atomic_idx); 116 #endif 117 } 118 119 #endif 120 121 /* 122 * Prevent people trying to call kunmap_atomic() as if it were kunmap() 123 * kunmap_atomic() should get the return value of kmap_atomic, not the page. 124 */ 125 #define kunmap_atomic(addr) \ 126 do { \ 127 BUILD_BUG_ON(__same_type((addr), struct page *)); \ 128 __kunmap_atomic(addr); \ 129 } while (0) 130 131 132 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */ 133 #ifndef clear_user_highpage 134 static inline void clear_user_highpage(struct page *page, unsigned long vaddr) 135 { 136 void *addr = kmap_atomic(page); 137 clear_user_page(addr, vaddr, page); 138 kunmap_atomic(addr); 139 } 140 #endif 141 142 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE 143 /** 144 * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags 145 * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE 146 * @vma: The VMA the page is to be allocated for 147 * @vaddr: The virtual address the page will be inserted into 148 * 149 * This function will allocate a page for a VMA but the caller is expected 150 * to specify via movableflags whether the page will be movable in the 151 * future or not 152 * 153 * An architecture may override this function by defining 154 * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own 155 * implementation. 156 */ 157 static inline struct page * 158 __alloc_zeroed_user_highpage(gfp_t movableflags, 159 struct vm_area_struct *vma, 160 unsigned long vaddr) 161 { 162 struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags, 163 vma, vaddr); 164 165 if (page) 166 clear_user_highpage(page, vaddr); 167 168 return page; 169 } 170 #endif 171 172 /** 173 * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move 174 * @vma: The VMA the page is to be allocated for 175 * @vaddr: The virtual address the page will be inserted into 176 * 177 * This function will allocate a page for a VMA that the caller knows will 178 * be able to migrate in the future using move_pages() or reclaimed 179 */ 180 static inline struct page * 181 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma, 182 unsigned long vaddr) 183 { 184 return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr); 185 } 186 187 static inline void clear_highpage(struct page *page) 188 { 189 void *kaddr = kmap_atomic(page); 190 clear_page(kaddr); 191 kunmap_atomic(kaddr); 192 } 193 194 static inline void zero_user_segments(struct page *page, 195 unsigned start1, unsigned end1, 196 unsigned start2, unsigned end2) 197 { 198 void *kaddr = kmap_atomic(page); 199 200 BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE); 201 202 if (end1 > start1) 203 memset(kaddr + start1, 0, end1 - start1); 204 205 if (end2 > start2) 206 memset(kaddr + start2, 0, end2 - start2); 207 208 kunmap_atomic(kaddr); 209 flush_dcache_page(page); 210 } 211 212 static inline void zero_user_segment(struct page *page, 213 unsigned start, unsigned end) 214 { 215 zero_user_segments(page, start, end, 0, 0); 216 } 217 218 static inline void zero_user(struct page *page, 219 unsigned start, unsigned size) 220 { 221 zero_user_segments(page, start, start + size, 0, 0); 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); 232 vto = kmap_atomic(to); 233 copy_user_page(vto, vfrom, vaddr, to); 234 kunmap_atomic(vto); 235 kunmap_atomic(vfrom); 236 } 237 238 #endif 239 240 #ifndef __HAVE_ARCH_COPY_HIGHPAGE 241 242 static inline void copy_highpage(struct page *to, struct page *from) 243 { 244 char *vfrom, *vto; 245 246 vfrom = kmap_atomic(from); 247 vto = kmap_atomic(to); 248 copy_page(vto, vfrom); 249 kunmap_atomic(vto); 250 kunmap_atomic(vfrom); 251 } 252 253 #endif 254 255 #endif /* _LINUX_HIGHMEM_H */ 256