1#ifndef _LINUX_HIGHMEM_H 2#define _LINUX_HIGHMEM_H 3 4#include <linux/config.h> 5#include <asm/pgalloc.h> 6 7#ifdef CONFIG_HIGHMEM 8 9extern struct page *highmem_start_page; 10 11#include <asm/highmem.h> 12 13/* declarations for linux/mm/highmem.c */ 14unsigned int nr_free_highpages(void); 15 16extern struct buffer_head *create_bounce(int rw, struct buffer_head * bh_orig); 17 18static inline char *bh_kmap(struct buffer_head *bh) 19{ 20 return kmap(bh->b_page) + bh_offset(bh); 21} 22 23static inline void bh_kunmap(struct buffer_head *bh) 24{ 25 kunmap(bh->b_page); 26} 27 28/* 29 * remember to add offset! and never ever reenable interrupts between a 30 * bh_kmap_irq and bh_kunmap_irq!! 31 */ 32static inline char *bh_kmap_irq(struct buffer_head *bh, unsigned long *flags) 33{ 34 unsigned long addr; 35 36 __save_flags(*flags); 37 38 /* 39 * could be low 40 */ 41 if (!PageHighMem(bh->b_page)) 42 return bh->b_data; 43 44 /* 45 * it's a highmem page 46 */ 47 __cli(); 48 addr = (unsigned long) kmap_atomic(bh->b_page, KM_BH_IRQ); 49 50 if (addr & ~PAGE_MASK) 51 BUG(); 52 53 return (char *) addr + bh_offset(bh); 54} 55 56static inline void bh_kunmap_irq(char *buffer, unsigned long *flags) 57{ 58 unsigned long ptr = (unsigned long) buffer & PAGE_MASK; 59 60 kunmap_atomic((void *) ptr, KM_BH_IRQ); 61 __restore_flags(*flags); 62} 63 64#else /* CONFIG_HIGHMEM */ 65 66static inline unsigned int nr_free_highpages(void) { return 0; } 67 68static inline void *kmap(struct page *page) { return page_address(page); } 69 70#define kunmap(page) do { } while (0) 71 72#define kmap_atomic(page,idx) kmap(page) 73#define kunmap_atomic(page,idx) kunmap(page) 74 75#define bh_kmap(bh) ((bh)->b_data) 76#define bh_kunmap(bh) do { } while (0) 77#define bh_kmap_irq(bh, flags) ((bh)->b_data) 78#define bh_kunmap_irq(bh, flags) do { *(flags) = 0; } while (0) 79 80#endif /* CONFIG_HIGHMEM */ 81 82/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */ 83static inline void clear_user_highpage(struct page *page, unsigned long vaddr) 84{ 85 void *addr = kmap_atomic(page, KM_USER0); 86 clear_user_page(addr, vaddr); 87 kunmap_atomic(addr, KM_USER0); 88} 89 90static inline void clear_highpage(struct page *page) 91{ 92 clear_page(kmap(page)); 93 kunmap(page); 94} 95 96/* 97 * Same but also flushes aliased cache contents to RAM. 98 */ 99static inline void memclear_highpage_flush(struct page *page, unsigned int offset, unsigned int size) 100{ 101 char *kaddr; 102 103 if (offset + size > PAGE_SIZE) 104 out_of_line_bug(); 105 kaddr = kmap(page); 106 memset(kaddr + offset, 0, size); 107 flush_dcache_page(page); 108 flush_page_to_ram(page); 109 kunmap(page); 110} 111 112static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr) 113{ 114 char *vfrom, *vto; 115 116 vfrom = kmap_atomic(from, KM_USER0); 117 vto = kmap_atomic(to, KM_USER1); 118 copy_user_page(vto, vfrom, vaddr); 119 kunmap_atomic(vfrom, KM_USER0); 120 kunmap_atomic(vto, KM_USER1); 121} 122 123#endif /* _LINUX_HIGHMEM_H */ 124