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 atomic_long_t _totalhigh_pages; 40 static inline unsigned long totalhigh_pages(void) 41 { 42 return (unsigned long)atomic_long_read(&_totalhigh_pages); 43 } 44 45 static inline void totalhigh_pages_inc(void) 46 { 47 atomic_long_inc(&_totalhigh_pages); 48 } 49 50 static inline void totalhigh_pages_dec(void) 51 { 52 atomic_long_dec(&_totalhigh_pages); 53 } 54 55 static inline void totalhigh_pages_add(long count) 56 { 57 atomic_long_add(count, &_totalhigh_pages); 58 } 59 60 static inline void totalhigh_pages_set(long val) 61 { 62 atomic_long_set(&_totalhigh_pages, val); 63 } 64 65 void kmap_flush_unused(void); 66 67 struct page *kmap_to_page(void *addr); 68 69 #else /* CONFIG_HIGHMEM */ 70 71 static inline unsigned int nr_free_highpages(void) { return 0; } 72 73 static inline struct page *kmap_to_page(void *addr) 74 { 75 return virt_to_page(addr); 76 } 77 78 static inline unsigned long totalhigh_pages(void) { return 0UL; } 79 80 #ifndef ARCH_HAS_KMAP 81 static inline void *kmap(struct page *page) 82 { 83 might_sleep(); 84 return page_address(page); 85 } 86 87 static inline void kunmap(struct page *page) 88 { 89 } 90 91 static inline void *kmap_atomic(struct page *page) 92 { 93 preempt_disable(); 94 pagefault_disable(); 95 return page_address(page); 96 } 97 #define kmap_atomic_prot(page, prot) kmap_atomic(page) 98 99 static inline void __kunmap_atomic(void *addr) 100 { 101 pagefault_enable(); 102 preempt_enable(); 103 } 104 105 #define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn)) 106 107 #define kmap_flush_unused() do {} while(0) 108 #endif 109 110 #endif /* CONFIG_HIGHMEM */ 111 112 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32) 113 114 DECLARE_PER_CPU(int, __kmap_atomic_idx); 115 116 static inline int kmap_atomic_idx_push(void) 117 { 118 int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1; 119 120 #ifdef CONFIG_DEBUG_HIGHMEM 121 WARN_ON_ONCE(in_irq() && !irqs_disabled()); 122 BUG_ON(idx >= KM_TYPE_NR); 123 #endif 124 return idx; 125 } 126 127 static inline int kmap_atomic_idx(void) 128 { 129 return __this_cpu_read(__kmap_atomic_idx) - 1; 130 } 131 132 static inline void kmap_atomic_idx_pop(void) 133 { 134 #ifdef CONFIG_DEBUG_HIGHMEM 135 int idx = __this_cpu_dec_return(__kmap_atomic_idx); 136 137 BUG_ON(idx < 0); 138 #else 139 __this_cpu_dec(__kmap_atomic_idx); 140 #endif 141 } 142 143 #endif 144 145 /* 146 * Prevent people trying to call kunmap_atomic() as if it were kunmap() 147 * kunmap_atomic() should get the return value of kmap_atomic, not the page. 148 */ 149 #define kunmap_atomic(addr) \ 150 do { \ 151 BUILD_BUG_ON(__same_type((addr), struct page *)); \ 152 __kunmap_atomic(addr); \ 153 } while (0) 154 155 156 /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */ 157 #ifndef clear_user_highpage 158 static inline void clear_user_highpage(struct page *page, unsigned long vaddr) 159 { 160 void *addr = kmap_atomic(page); 161 clear_user_page(addr, vaddr, page); 162 kunmap_atomic(addr); 163 } 164 #endif 165 166 #ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE 167 /** 168 * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags 169 * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE 170 * @vma: The VMA the page is to be allocated for 171 * @vaddr: The virtual address the page will be inserted into 172 * 173 * This function will allocate a page for a VMA but the caller is expected 174 * to specify via movableflags whether the page will be movable in the 175 * future or not 176 * 177 * An architecture may override this function by defining 178 * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own 179 * implementation. 180 */ 181 static inline struct page * 182 __alloc_zeroed_user_highpage(gfp_t movableflags, 183 struct vm_area_struct *vma, 184 unsigned long vaddr) 185 { 186 struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags, 187 vma, vaddr); 188 189 if (page) 190 clear_user_highpage(page, vaddr); 191 192 return page; 193 } 194 #endif 195 196 /** 197 * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move 198 * @vma: The VMA the page is to be allocated for 199 * @vaddr: The virtual address the page will be inserted into 200 * 201 * This function will allocate a page for a VMA that the caller knows will 202 * be able to migrate in the future using move_pages() or reclaimed 203 */ 204 static inline struct page * 205 alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma, 206 unsigned long vaddr) 207 { 208 return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr); 209 } 210 211 static inline void clear_highpage(struct page *page) 212 { 213 void *kaddr = kmap_atomic(page); 214 clear_page(kaddr); 215 kunmap_atomic(kaddr); 216 } 217 218 static inline void zero_user_segments(struct page *page, 219 unsigned start1, unsigned end1, 220 unsigned start2, unsigned end2) 221 { 222 void *kaddr = kmap_atomic(page); 223 224 BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE); 225 226 if (end1 > start1) 227 memset(kaddr + start1, 0, end1 - start1); 228 229 if (end2 > start2) 230 memset(kaddr + start2, 0, end2 - start2); 231 232 kunmap_atomic(kaddr); 233 flush_dcache_page(page); 234 } 235 236 static inline void zero_user_segment(struct page *page, 237 unsigned start, unsigned end) 238 { 239 zero_user_segments(page, start, end, 0, 0); 240 } 241 242 static inline void zero_user(struct page *page, 243 unsigned start, unsigned size) 244 { 245 zero_user_segments(page, start, start + size, 0, 0); 246 } 247 248 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE 249 250 static inline void copy_user_highpage(struct page *to, struct page *from, 251 unsigned long vaddr, struct vm_area_struct *vma) 252 { 253 char *vfrom, *vto; 254 255 vfrom = kmap_atomic(from); 256 vto = kmap_atomic(to); 257 copy_user_page(vto, vfrom, vaddr, to); 258 kunmap_atomic(vto); 259 kunmap_atomic(vfrom); 260 } 261 262 #endif 263 264 #ifndef __HAVE_ARCH_COPY_HIGHPAGE 265 266 static inline void copy_highpage(struct page *to, struct page *from) 267 { 268 char *vfrom, *vto; 269 270 vfrom = kmap_atomic(from); 271 vto = kmap_atomic(to); 272 copy_page(vto, vfrom); 273 kunmap_atomic(vto); 274 kunmap_atomic(vfrom); 275 } 276 277 #endif 278 279 #endif /* _LINUX_HIGHMEM_H */ 280