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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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106 lines
2.8 KiB
C
106 lines
2.8 KiB
C
/*
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* highmem.h: virtual kernel memory mappings for high memory
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*
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* Used in CONFIG_HIGHMEM systems for memory pages which
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* are not addressable by direct kernel virtual addresses.
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*
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* Copyright (C) 1999 Gerhard Wichert, Siemens AG
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* Gerhard.Wichert@pdb.siemens.de
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*
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*
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* Redesigned the x86 32-bit VM architecture to deal with
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* up to 16 Terabyte physical memory. With current x86 CPUs
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* we now support up to 64 Gigabytes physical RAM.
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*
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* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
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*/
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#ifndef _ASM_HIGHMEM_H
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#define _ASM_HIGHMEM_H
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#ifdef __KERNEL__
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#include <linux/config.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <asm/kmap_types.h>
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/* undef for production */
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#define HIGHMEM_DEBUG 1
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/* declarations for highmem.c */
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extern unsigned long highstart_pfn, highend_pfn;
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extern pte_t *kmap_pte;
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extern pgprot_t kmap_prot;
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extern pte_t *pkmap_page_table;
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/*
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* Right now we initialize only a single pte table. It can be extended
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* easily, subsequent pte tables have to be allocated in one physical
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* chunk of RAM.
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*/
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#define PKMAP_BASE (0xfe000000UL)
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#define LAST_PKMAP 1024
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#define LAST_PKMAP_MASK (LAST_PKMAP-1)
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#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
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#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
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extern void * kmap_high(struct page *page);
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extern void kunmap_high(struct page *page);
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/*
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* CONFIG_LIMITED_DMA is for systems with DMA limitations such as Momentum's
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* Jaguar ATX. This option exploits the highmem code in the kernel so is
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* always enabled together with CONFIG_HIGHMEM but at this time doesn't
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* actually add highmem functionality.
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*/
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#ifdef CONFIG_LIMITED_DMA
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/*
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* These are the default functions for the no-highmem case from
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* <linux/highmem.h>
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*/
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static inline void *kmap(struct page *page)
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{
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might_sleep();
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return page_address(page);
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}
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#define kunmap(page) do { (void) (page); } while (0)
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static inline void *kmap_atomic(struct page *page, enum km_type type)
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{
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return page_address(page);
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}
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static inline void kunmap_atomic(void *kvaddr, enum km_type type) { }
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#define kmap_atomic_pfn(pfn, idx) page_address(pfn_to_page(pfn))
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#define kmap_atomic_to_page(ptr) virt_to_page(ptr)
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#define flush_cache_kmaps() do { } while (0)
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#else /* LIMITED_DMA */
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extern void *__kmap(struct page *page);
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extern void __kunmap(struct page *page);
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extern void *__kmap_atomic(struct page *page, enum km_type type);
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extern void __kunmap_atomic(void *kvaddr, enum km_type type);
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extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
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extern struct page *__kmap_atomic_to_page(void *ptr);
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#define kmap __kmap
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#define kunmap __kunmap
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#define kmap_atomic __kmap_atomic
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#define kunmap_atomic __kunmap_atomic
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#define kmap_atomic_to_page __kmap_atomic_to_page
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#define flush_cache_kmaps() flush_cache_all()
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#endif /* LIMITED_DMA */
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#endif /* __KERNEL__ */
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#endif /* _ASM_HIGHMEM_H */
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