projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * highmem.h: virtual kernel memory mappings for high memory | |
| 3 | * | |
| 4 | * PowerPC version, stolen from the i386 version. | |
| 5 | * | |
| 6 | * Used in CONFIG_HIGHMEM systems for memory pages which | |
| 7 | * are not addressable by direct kernel virtual addresses. | |
| 8 | * | |
| 9 | * Copyright (C) 1999 Gerhard Wichert, Siemens AG | |
| 10 | * [email protected] | |
| 11 | * | |
| 12 | * | |
| 13 | * Redesigned the x86 32-bit VM architecture to deal with | |
| 14 | * up to 16 Terrabyte physical memory. With current x86 CPUs | |
| 15 | * we now support up to 64 Gigabytes physical RAM. | |
| 16 | * | |
| 17 | * Copyright (C) 1999 Ingo Molnar <[email protected]> | |
| 18 | */ | |
| 19 | ||
| 20 | #ifndef _ASM_HIGHMEM_H | |
| 21 | #define _ASM_HIGHMEM_H | |
| 22 | ||
| 23 | #ifdef __KERNEL__ | |
| 24 | ||
| 25 | #include <linux/init.h> | |
| 26 | #include <linux/interrupt.h> | |
| 27 | #include <asm/kmap_types.h> | |
| 28 | #include <asm/tlbflush.h> | |
| 29 | #include <asm/page.h> | |
| 30 | ||
| 31 | /* undef for production */ | |
| 32 | #define HIGHMEM_DEBUG 1 | |
| 33 | ||
| 34 | extern pte_t *kmap_pte; | |
| 35 | extern pgprot_t kmap_prot; | |
| 36 | extern pte_t *pkmap_page_table; | |
| 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. | |
| 42 | */ | |
| 43 | #define PKMAP_BASE CONFIG_HIGHMEM_START | |
| 44 | #define LAST_PKMAP (1 << PTE_SHIFT) | |
| 45 | #define LAST_PKMAP_MASK (LAST_PKMAP-1) | |
| 46 | #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT) | |
| 47 | #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) | |
| 48 | ||
| 49 | #define KMAP_FIX_BEGIN (PKMAP_BASE + 0x00400000UL) | |
| 50 | ||
| 51 | extern void *kmap_high(struct page *page); | |
| 52 | extern void kunmap_high(struct page *page); | |
| 53 | ||
| 54 | static inline void *kmap(struct page *page) | |
| 55 | { | |
| 56 | might_sleep(); | |
| 57 | if (!PageHighMem(page)) | |
| 58 | return page_address(page); | |
| 59 | return kmap_high(page); | |
| 60 | } | |
| 61 | ||
| 62 | static inline void kunmap(struct page *page) | |
| 63 | { | |
| 64 | BUG_ON(in_interrupt()); | |
| 65 | if (!PageHighMem(page)) | |
| 66 | return; | |
| 67 | kunmap_high(page); | |
| 68 | } | |
| 69 | ||
| 70 | /* | |
| 71 | * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap | |
| 72 | * gives a more generic (and caching) interface. But kmap_atomic can | |
| 73 | * be used in IRQ contexts, so in some (very limited) cases we need | |
| 74 | * it. | |
| 75 | */ | |
| 76 | static inline void *kmap_atomic(struct page *page, enum km_type type) | |
| 77 | { | |
| 78 | unsigned int idx; | |
| 79 | unsigned long vaddr; | |
| 80 | ||
| 81 | /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ | |
| 82 | inc_preempt_count(); | |
| 83 | if (!PageHighMem(page)) | |
| 84 | return page_address(page); | |
| 85 | ||
| 86 | idx = type + KM_TYPE_NR*smp_processor_id(); | |
| 87 | vaddr = KMAP_FIX_BEGIN + idx * PAGE_SIZE; | |
| 88 | #ifdef HIGHMEM_DEBUG | |
| 89 | BUG_ON(!pte_none(*(kmap_pte+idx))); | |
| 90 | #endif | |
| 91 | set_pte_at(&init_mm, vaddr, kmap_pte+idx, mk_pte(page, kmap_prot)); | |
| 92 | flush_tlb_page(NULL, vaddr); | |
| 93 | ||
| 94 | return (void*) vaddr; | |
| 95 | } | |
| 96 | ||
| 97 | static inline void kunmap_atomic(void *kvaddr, enum km_type type) | |
| 98 | { | |
| 99 | #ifdef HIGHMEM_DEBUG | |
| 100 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; | |
| 101 | unsigned int idx = type + KM_TYPE_NR*smp_processor_id(); | |
| 102 | ||
| 103 | if (vaddr < KMAP_FIX_BEGIN) { // FIXME | |
| 104 | dec_preempt_count(); | |
| 105 | preempt_check_resched(); | |
| 106 | return; | |
| 107 | } | |
| 108 | ||
| 109 | BUG_ON(vaddr != KMAP_FIX_BEGIN + idx * PAGE_SIZE); | |
| 110 | ||
| 111 | /* | |
| 112 | * force other mappings to Oops if they'll try to access | |
| 113 | * this pte without first remap it | |
| 114 | */ | |
| 115 | pte_clear(&init_mm, vaddr, kmap_pte+idx); | |
| 116 | flush_tlb_page(NULL, vaddr); | |
| 117 | #endif | |
| 118 | dec_preempt_count(); | |
| 119 | preempt_check_resched(); | |
| 120 | } | |
| 121 | ||
| 122 | static inline struct page *kmap_atomic_to_page(void *ptr) | |
| 123 | { | |
| 124 | unsigned long idx, vaddr = (unsigned long) ptr; | |
| 125 | ||
| 126 | if (vaddr < KMAP_FIX_BEGIN) | |
| 127 | return virt_to_page(ptr); | |
| 128 | ||
| 129 | idx = (vaddr - KMAP_FIX_BEGIN) >> PAGE_SHIFT; | |
| 130 | return pte_page(kmap_pte[idx]); | |
| 131 | } | |
| 132 | ||
| 133 | #define flush_cache_kmaps() flush_cache_all() | |
| 134 | ||
| 135 | #endif /* __KERNEL__ */ | |
| 136 | ||
| 137 | #endif /* _ASM_HIGHMEM_H */ |