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- /*
- * 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/init.h>
- #include <linux/interrupt.h>
- #include <linux/uaccess.h>
- #include <asm/fixmap.h>
- 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.
- */
- /*
- * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
- * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
- * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
- * in case of 16K/64K/256K page sizes.
- */
- #define PKMAP_ORDER PTE_SHIFT
- #define LAST_PKMAP (1 << PKMAP_ORDER)
- #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
- & PMD_MASK)
- #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);
- extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
- extern void __kunmap_atomic(void *kvaddr);
- static inline void *kmap(struct page *page)
- {
- might_sleep();
- 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);
- }
- static inline void *kmap_atomic(struct page *page)
- {
- return kmap_atomic_prot(page, kmap_prot);
- }
- #define flush_cache_kmaps() { flush_icache(); flush_dcache(); }
- #endif /* __KERNEL__ */
- #endif /* _ASM_HIGHMEM_H */
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