/* * highmem.h: virtual kernel memory mappings for high memory * * Used in CONFIG_HIGHMEM systems for memory pages which * are not addressable by direct kernel virtual addresses. * * Copyright (C) 1999 Gerhard Wichert, Siemens AG * Gerhard.Wichert@pdb.siemens.de * * * Redesigned the x86 32-bit VM architecture to deal with * up to 16 Terrabyte physical memory. With current x86 CPUs * we now support up to 64 Gigabytes physical RAM. * * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> */ #ifndef _ASM_HIGHMEM_H #define _ASM_HIGHMEM_H #ifdef __KERNEL__ #include <linux/interrupt.h> #include <asm/fixmap.h> #include <asm/vaddrs.h> #include <asm/kmap_types.h> #include <asm/pgtable.h> /* declarations for highmem.c */ extern unsigned long highstart_pfn, highend_pfn; extern pte_t *kmap_pte; extern pgprot_t kmap_prot; extern pte_t *pkmap_page_table; extern void kmap_init(void) __init; /* * Right now we initialize only a single pte table. It can be extended * easily, subsequent pte tables have to be allocated in one physical * chunk of RAM. Currently the simplest way to do this is to align the * pkmap region on a pagetable boundary (4MB). */ #define LAST_PKMAP 1024 #define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT) #define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT)) #define LAST_PKMAP_MASK (LAST_PKMAP - 1) #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT) #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT)) #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP)) extern void *kmap_high(struct page *page); extern void kunmap_high(struct page *page); static inline void *kmap(struct page *page) { BUG_ON(in_interrupt()); if (!PageHighMem(page)) return page_address(page); return kmap_high(page); } static inline void kunmap(struct page *page) { BUG_ON(in_interrupt()); if (!PageHighMem(page)) return; kunmap_high(page); } extern void *kmap_atomic(struct page *page, enum km_type type); extern void kunmap_atomic(void *kvaddr, enum km_type type); extern struct page *kmap_atomic_to_page(void *vaddr); #define flush_cache_kmaps() flush_cache_all() #endif /* __KERNEL__ */ #endif /* _ASM_HIGHMEM_H */