mirror of https://gitee.com/openkylin/linux.git
67 lines
2.0 KiB
C
67 lines
2.0 KiB
C
#ifndef _ASM_HIGHMEM_H
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#define _ASM_HIGHMEM_H
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#include <asm/kmap_types.h>
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#define PKMAP_BASE (PAGE_OFFSET - PMD_SIZE)
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#define LAST_PKMAP PTRS_PER_PTE
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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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#define kmap_prot PAGE_KERNEL
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#define flush_cache_kmaps() \
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do { \
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if (cache_is_vivt()) \
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flush_cache_all(); \
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} while (0)
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extern pte_t *pkmap_page_table;
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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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* The reason for kmap_high_get() is to ensure that the currently kmap'd
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* page usage count does not decrease to zero while we're using its
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* existing virtual mapping in an atomic context. With a VIVT cache this
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* is essential to do, but with a VIPT cache this is only an optimization
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* so not to pay the price of establishing a second mapping if an existing
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* one can be used. However, on platforms without hardware TLB maintenance
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* broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since
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* the locking involved must also disable IRQs which is incompatible with
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* the IPI mechanism used by global TLB operations.
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*/
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#define ARCH_NEEDS_KMAP_HIGH_GET
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#if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6)
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#undef ARCH_NEEDS_KMAP_HIGH_GET
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#if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT)
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#error "The sum of features in your kernel config cannot be supported together"
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#endif
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#endif
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#ifdef ARCH_NEEDS_KMAP_HIGH_GET
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extern void *kmap_high_get(struct page *page);
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#else
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static inline void *kmap_high_get(struct page *page)
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{
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return NULL;
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}
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#endif
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/*
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* The following functions are already defined by <linux/highmem.h>
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* when CONFIG_HIGHMEM is not set.
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*/
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#ifdef CONFIG_HIGHMEM
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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);
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extern void __kunmap_atomic(void *kvaddr);
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extern void *kmap_atomic_pfn(unsigned long pfn);
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extern struct page *kmap_atomic_to_page(const void *ptr);
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#endif
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#endif
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