/* * 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 Terabyte 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/config.h> #include <linux/init.h> #include <linux/interrupt.h> #include <asm/kmap_types.h> /* undef for production */ #define HIGHMEM_DEBUG 1 /* 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; /* * 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. */ #define PKMAP_BASE (0xfe000000UL) #define LAST_PKMAP 1024 #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)) extern void * kmap_high(struct page *page); extern void kunmap_high(struct page *page); /* * CONFIG_LIMITED_DMA is for systems with DMA limitations such as Momentum's * Jaguar ATX. This option exploits the highmem code in the kernel so is * always enabled together with CONFIG_HIGHMEM but at this time doesn't * actually add highmem functionality. */ #ifdef CONFIG_LIMITED_DMA /* * These are the default functions for the no-highmem case from * <linux/highmem.h> */ static inline void *kmap(struct page *page) { might_sleep(); return page_address(page); } #define kunmap(page) do { (void) (page); } while (0) static inline void *kmap_atomic(struct page *page, enum km_type type) { return page_address(page); } static inline void kunmap_atomic(void *kvaddr, enum km_type type) { } #define kmap_atomic_to_page(ptr) virt_to_page(ptr) #define flush_cache_kmaps() do { } while (0) #else /* LIMITED_DMA */ extern void *__kmap(struct page *page); extern void __kunmap(struct page *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 *ptr); #define kmap __kmap #define kunmap __kunmap #define kmap_atomic __kmap_atomic #define kunmap_atomic __kunmap_atomic #define kmap_atomic_to_page __kmap_atomic_to_page #define flush_cache_kmaps() flush_cache_all() #endif /* LIMITED_DMA */ #endif /* __KERNEL__ */ #endif /* _ASM_HIGHMEM_H */