| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * highmem.h: virtual kernel memory mappings for high memory |
| 3 | * |
| 4 | * Used in CONFIG_HIGHMEM systems for memory pages which |
| 5 | * are not addressable by direct kernel virtual addresses. |
| 6 | * |
| 7 | * Copyright (C) 1999 Gerhard Wichert, Siemens AG |
| 8 | * Gerhard.Wichert@pdb.siemens.de |
| 9 | * |
| 10 | * |
| 11 | * Redesigned the x86 32-bit VM architecture to deal with |
| 12 | * up to 16 Terrabyte physical memory. With current x86 CPUs |
| 13 | * we now support up to 64 Gigabytes physical RAM. |
| 14 | * |
| 15 | * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> |
| 16 | */ |
| 17 | |
| 18 | #ifndef _ASM_HIGHMEM_H |
| 19 | #define _ASM_HIGHMEM_H |
| 20 | |
| 21 | #ifdef __KERNEL__ |
| 22 | |
| 23 | #include <linux/interrupt.h> |
| 24 | #include <asm/fixmap.h> |
| 25 | #include <asm/vaddrs.h> |
| 26 | #include <asm/kmap_types.h> |
| 27 | #include <asm/pgtable.h> |
| 28 | |
| 29 | /* declarations for highmem.c */ |
| 30 | extern unsigned long highstart_pfn, highend_pfn; |
| 31 | |
| 32 | extern pte_t *kmap_pte; |
| 33 | extern pgprot_t kmap_prot; |
| 34 | extern pte_t *pkmap_page_table; |
| 35 | |
| 36 | extern void kmap_init(void) __init; |
| 37 | |
| 38 | /* |
| 39 | * Right now we initialize only a single pte table. It can be extended |
| 40 | * easily, subsequent pte tables have to be allocated in one physical |
| 41 | * chunk of RAM. Currently the simplest way to do this is to align the |
| 42 | * pkmap region on a pagetable boundary (4MB). |
| 43 | */ |
| 44 | #define LAST_PKMAP 1024 |
| 45 | #define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT) |
| 46 | #define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT)) |
| 47 | |
| 48 | #define LAST_PKMAP_MASK (LAST_PKMAP - 1) |
| 49 | #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT) |
| 50 | #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) |
| 51 | |
| 52 | #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP)) |
| 53 | |
| 54 | extern void *kmap_high(struct page *page); |
| 55 | extern void kunmap_high(struct page *page); |
| 56 | |
| 57 | static inline void *kmap(struct page *page) |
| 58 | { |
| 59 | BUG_ON(in_interrupt()); |
| 60 | if (!PageHighMem(page)) |
| 61 | return page_address(page); |
| 62 | return kmap_high(page); |
| 63 | } |
| 64 | |
| 65 | static inline void kunmap(struct page *page) |
| 66 | { |
| 67 | BUG_ON(in_interrupt()); |
| 68 | if (!PageHighMem(page)) |
| 69 | return; |
| 70 | kunmap_high(page); |
| 71 | } |
| 72 | |
| 73 | extern void *kmap_atomic(struct page *page, enum km_type type); |
| 74 | extern void kunmap_atomic(void *kvaddr, enum km_type type); |
| 75 | extern struct page *kmap_atomic_to_page(void *vaddr); |
| 76 | |
| 77 | #define flush_cache_kmaps() flush_cache_all() |
| 78 | |
| 79 | #endif /* __KERNEL__ */ |
| 80 | |
| 81 | #endif /* _ASM_HIGHMEM_H */ |