Viewing file:  highmem.h (2.17 KB) -rw-r--r--
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#ifndef _ASM_HIGHMEM_H
#define _ASM_HIGHMEM_H
#include <asm/kmap_types.h>
#define PKMAP_BASE (PAGE_OFFSET - PMD_SIZE)
#define LAST_PKMAP PTRS_PER_PTE
#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 kmap_prot PAGE_KERNEL
#define flush_cache_kmaps() \
do { \
if (cache_is_vivt()) \
flush_cache_all(); \
} while (0)
extern pte_t *pkmap_page_table;
extern void *kmap_high(struct page *page);
extern void kunmap_high(struct page *page);
/*
* The reason for kmap_high_get() is to ensure that the currently kmap'd
* page usage count does not decrease to zero while we're using its
* existing virtual mapping in an atomic context. With a VIVT cache this
* is essential to do, but with a VIPT cache this is only an optimization
* so not to pay the price of establishing a second mapping if an existing
* one can be used. However, on platforms without hardware TLB maintenance
* broadcast, we simply cannot use ARCH_NEEDS_KMAP_HIGH_GET at all since
* the locking involved must also disable IRQs which is incompatible with
* the IPI mechanism used by global TLB operations.
*/
#define ARCH_NEEDS_KMAP_HIGH_GET
#if defined(CONFIG_SMP) && defined(CONFIG_CPU_TLB_V6)
#undef ARCH_NEEDS_KMAP_HIGH_GET
#if defined(CONFIG_HIGHMEM) && defined(CONFIG_CPU_CACHE_VIVT)
#error "The sum of features in your kernel config cannot be supported together"
#endif
#endif
/*
* Needed to be able to broadcast the TLB invalidation for kmap.
*/
#ifdef CONFIG_ARM_ERRATA_798181
#undef ARCH_NEEDS_KMAP_HIGH_GET
#endif
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
extern void *kmap_high_get(struct page *page);
#else
static inline void *kmap_high_get(struct page *page)
{
return NULL;
}
#endif
/*
* The following functions are already defined by <linux/highmem.h>
* when CONFIG_HIGHMEM is not set.
*/
#ifdef CONFIG_HIGHMEM
extern void *kmap(struct page *page);
extern void kunmap(struct page *page);
extern void *kmap_atomic(struct page *page);
extern void __kunmap_atomic(void *kvaddr);
extern void *kmap_atomic_pfn(unsigned long pfn);
extern struct page *kmap_atomic_to_page(const void *ptr);
#endif
#endif
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