1 /* SPDX-License-Identifier: GPL-2.0 */
14 #include "highmem-internal.h"
17  * kmap - Map a page for long term usage
18  * @page:	Pointer to the page to be mapped
37 static inline void *kmap(struct page *page);
40  * kunmap - Unmap the virtual address mapped by kmap()
41  * @page:	Pointer to the page which was mapped by kmap()
46 static inline void kunmap(struct page *page);
49  * kmap_to_page - Get the page for a kmap'ed address
52  * Returns: The page which is mapped to @addr.
54 static inline struct page *kmap_to_page(void *addr);
57  * kmap_flush_unused - Flush all unused kmap mappings in order to
63  * kmap_local_page - Map a page for temporary usage
64  * @page: Pointer to the page to be mapped
92  * On HIGHMEM enabled systems mapping a highmem page has the side effect of
96 static inline void *kmap_local_page(struct page *page);
99  * kmap_local_folio - Map a page in this folio for temporary usage
100  * @folio: The folio containing the page.
101  * @offset: The byte offset within the folio which identifies the page.
126  * On HIGHMEM enabled systems mapping a highmem page has the side effect of
131  * Return: The virtual address of @offset.
133 static inline void *kmap_local_folio(struct folio *folio, size_t offset);
136  * kmap_atomic - Atomically map a page for temporary usage - Deprecated!
137  * @page:	Pointer to the page to be mapped
150  * page that might be allocated from high memory (see __GFP_HIGHMEM), for
151  * example a page in the pagecache.  The API has two functions, and they
154  *   // Find the page of interest.
155  *   struct page *page = find_get_page(mapping, offset);
157  *   // Gain access to the contents of that page.
158  *   void *vaddr = kmap_atomic(page);
160  *   // Do something to the contents of that page.
163  *   // Unmap that page.
169  * If you need to map two pages because you want to copy from one page to
180 static inline void *kmap_atomic(struct page *page);
187 static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vma…  in flush_anon_page()  argument
203 static inline void clear_user_highpage(struct page *page, unsigned long vaddr)  in clear_user_highpage()  argument
205 	void *addr = kmap_local_page(page);  in clear_user_highpage()
206 	clear_user_page(addr, vaddr, page);  in clear_user_highpage()
213 …* alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller kn…
214  * @vma: The VMA the page is to be allocated for
215  * @vaddr: The virtual address the page will be inserted into
217  * Returns: The allocated and zeroed HIGHMEM page
219  * This function will allocate a page for a VMA that the caller knows will
226 static inline struct page *
230 	struct page *page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);  in alloc_zeroed_user_highpage_movable()  local
232 	if (page)  in alloc_zeroed_user_highpage_movable()
233 		clear_user_highpage(page, vaddr);  in alloc_zeroed_user_highpage_movable()
235 	return page;  in alloc_zeroed_user_highpage_movable()
239 static inline void clear_highpage(struct page *page)  in clear_highpage()  argument
241 	void *kaddr = kmap_local_page(page);  in clear_highpage()
246 static inline void clear_highpage_kasan_tagged(struct page *page)  in clear_highpage_kasan_tagged()  argument
250 	tag = page_kasan_tag(page);  in clear_highpage_kasan_tagged()
251 	page_kasan_tag_reset(page);  in clear_highpage_kasan_tagged()
252 	clear_highpage(page);  in clear_highpage_kasan_tagged()
253 	page_kasan_tag_set(page, tag);  in clear_highpage_kasan_tagged()
258 static inline void tag_clear_highpage(struct page *page)  in tag_clear_highpage()  argument
265  * If we pass in a base or tail page, we can zero up to PAGE_SIZE.
266  * If we pass in a head page, we can zero up to the size of the compound page.
269 void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
272 static inline void zero_user_segments(struct page *page,  in zero_user_segments()  argument
276 	void *kaddr = kmap_local_page(page);  in zero_user_segments()
279 	BUG_ON(end1 > page_size(page) || end2 > page_size(page));  in zero_user_segments()
282 		memset(kaddr + start1, 0, end1 - start1);  in zero_user_segments()
285 		memset(kaddr + start2, 0, end2 - start2);  in zero_user_segments()
288 	for (i = 0; i < compound_nr(page); i++)  in zero_user_segments()
289 		flush_dcache_page(page + i);  in zero_user_segments()
293 static inline void zero_user_segment(struct page *page,  in zero_user_segment()  argument
296 	zero_user_segments(page, start, end, 0, 0);  in zero_user_segment()
299 static inline void zero_user(struct page *page,  in zero_user()  argument
302 	zero_user_segments(page, start, start + size, 0, 0);  in zero_user()
307 static inline void copy_user_highpage(struct page *to, struct page *from,  in copy_user_highpage()
324 static inline void copy_highpage(struct page *to, struct page *from)  in copy_highpage()
338 static inline void memcpy_page(struct page *dst_page, size_t dst_off,  in memcpy_page()
339 			       struct page *src_page, size_t src_off,  in memcpy_page()
351 static inline void memset_page(struct page *page, size_t offset, int val,  in memset_page()  argument
354 	char *addr = kmap_local_page(page);  in memset_page()
356 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memset_page()
357 	memset(addr + offset, val, len);  in memset_page()
361 static inline void memcpy_from_page(char *to, struct page *page,  in memcpy_from_page()  argument
362 				    size_t offset, size_t len)  in memcpy_from_page()  argument
364 	char *from = kmap_local_page(page);  in memcpy_from_page()
366 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memcpy_from_page()
367 	memcpy(to, from + offset, len);  in memcpy_from_page()
371 static inline void memcpy_to_page(struct page *page, size_t offset,  in memcpy_to_page()  argument
374 	char *to = kmap_local_page(page);  in memcpy_to_page()
376 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memcpy_to_page()
377 	memcpy(to + offset, from, len);  in memcpy_to_page()
378 	flush_dcache_page(page);  in memcpy_to_page()
382 static inline void memzero_page(struct page *page, size_t offset, size_t len)  in memzero_page()  argument
384 	char *addr = kmap_local_page(page);  in memzero_page()
386 	VM_BUG_ON(offset + len > PAGE_SIZE);  in memzero_page()
387 	memset(addr + offset, 0, len);  in memzero_page()
388 	flush_dcache_page(page);  in memzero_page()
393  * folio_zero_segments() - Zero two byte ranges in a folio.
403 	zero_user_segments(&folio->page, start1, xend1, start2, xend2);  in folio_zero_segments()
407  * folio_zero_segment() - Zero a byte range in a folio.
415 	zero_user_segments(&folio->page, start, xend, 0, 0);  in folio_zero_segment()
419  * folio_zero_range() - Zero a byte range in a folio.
427 	zero_user_segments(&folio->page, start, start + length, 0, 0);  in folio_zero_range()