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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 <asm/kmap_types.h>

#include <asm/pgtable.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, int nonblocking);

extern void kunmap_high(struct page *page);

static inline void *__kmap(struct page *page, int nonblocking)

{

        if (in_interrupt())

                out_of_line_bug();

        if (page < highmem_start_page)

                return page_address(page);

        return kmap_high(page, nonblocking);

}

#define kmap(page)              __kmap(page, 0)

#define kmap_nonblock(page)     __kmap(page, 1)

static inline void kunmap(struct page *page)

{

        if (in_interrupt())

                out_of_line_bug();

        if (page < highmem_start_page)

                return;

        kunmap_high(page);

}

/*

 * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap

 * gives a more generic (and caching) interface. But kmap_atomic can

 * be used in IRQ contexts, so in some (very limited) cases we need

 * it.

 */

static inline void *kmap_atomic(struct page *page, enum km_type type)

{

        enum fixed_addresses idx;

        unsigned long vaddr;

        if (page < highmem_start_page)

                return page_address(page);

        idx = type + KM_TYPE_NR*smp_processor_id();

        vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);

        set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));

        local_flush_tlb_one(vaddr);

        return (void*) vaddr;

}

static inline void kunmap_atomic(void *kvaddr, enum km_type type)

{

}

#endif /* __KERNEL__ */

#endif /* _ASM_HIGHMEM_H */