Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

#include <linux/highmem.h>

#include <linux/module.h>

void *kmap(struct page *page)

{

        might_sleep();

        if (!PageHighMem(page))

                return page_address(page);

        return kmap_high(page);

}

void kunmap(struct page *page)

{

        if (in_interrupt())

                BUG();

        if (!PageHighMem(page))

                return;

        kunmap_high(page);

}

/*

 * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because

 * no global lock is needed and because the kmap code must perform a global TLB

 * invalidation when the kmap pool wraps.

 *

 * However when holding an atomic kmap is is not legal to sleep, so atomic

 * kmaps are appropriate for short, tight code paths only.

 */

void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)

{

        enum fixed_addresses idx;

        unsigned long vaddr;

        /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */

        pagefault_disable();

        if (!PageHighMem(page))

                return page_address(page);

        idx = type + KM_TYPE_NR*smp_processor_id();

        vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);

        BUG_ON(!pte_none(*(kmap_pte-idx)));

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

        arch_flush_lazy_mmu_mode();

        return (void *)vaddr;

}

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

{

        return kmap_atomic_prot(page, type, kmap_prot);

}

void kunmap_atomic(void *kvaddr, enum km_type type)

{

        unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;

        enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();

        /*

         * Force other mappings to Oops if they'll try to access this pte

         * without first remap it.  Keeping stale mappings around is a bad idea

         * also, in case the page changes cacheability attributes or becomes

         * a protected page in a hypervisor.

         */

        if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))

                kpte_clear_flush(kmap_pte-idx, vaddr);

        else {

#ifdef CONFIG_DEBUG_HIGHMEM

                BUG_ON(vaddr < PAGE_OFFSET);

                BUG_ON(vaddr >= (unsigned long)high_memory);

#endif

        }

        arch_flush_lazy_mmu_mode();

        pagefault_enable();

}

/* This is the same as kmap_atomic() but can map memory that doesn't

 * have a struct page associated with it.

 */

void *kmap_atomic_pfn(unsigned long pfn, enum km_type type)

{

        enum fixed_addresses idx;

        unsigned long vaddr;

        pagefault_disable();

        idx = type + KM_TYPE_NR*smp_processor_id();

        vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);

        set_pte(kmap_pte-idx, pfn_pte(pfn, kmap_prot));

        arch_flush_lazy_mmu_mode();

        return (void*) vaddr;

}

struct page *kmap_atomic_to_page(void *ptr)

{

        unsigned long idx, vaddr = (unsigned long)ptr;

        pte_t *pte;

        if (vaddr < FIXADDR_START)

                return virt_to_page(ptr);

        idx = virt_to_fix(vaddr);

        pte = kmap_pte - (idx - FIX_KMAP_BEGIN);

        return pte_page(*pte);

}

EXPORT_SYMBOL(kmap);

EXPORT_SYMBOL(kunmap);

EXPORT_SYMBOL(kmap_atomic);

EXPORT_SYMBOL(kunmap_atomic);

EXPORT_SYMBOL(kmap_atomic_to_page);