highmem.c
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/* highmem.c: arch-specific highmem stuff
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#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);
}
EXPORT_SYMBOL(kmap);
void kunmap(struct page *page)
{
if (in_interrupt())
BUG();
if (!PageHighMem(page))
return;
kunmap_high(page);
}
EXPORT_SYMBOL(kunmap);
struct page *kmap_atomic_to_page(void *ptr)
{
return virt_to_page(ptr);
}
void *kmap_atomic(struct page *page)
{
unsigned long paddr;
int type;
pagefault_disable();
type = kmap_atomic_idx_push();
paddr = page_to_phys(page);
switch (type) {
/*
* The first 4 primary maps are reserved for architecture code
*/
case 0: return __kmap_atomic_primary(0, paddr, 6);
case 1: return __kmap_atomic_primary(0, paddr, 7);
case 2: return __kmap_atomic_primary(0, paddr, 8);
case 3: return __kmap_atomic_primary(0, paddr, 9);
case 4: return __kmap_atomic_primary(0, paddr, 10);
case 5 ... 5 + NR_TLB_LINES - 1:
return __kmap_atomic_secondary(type - 5, paddr);
default:
BUG();
return NULL;
}
}
EXPORT_SYMBOL(kmap_atomic);
void __kunmap_atomic(void *kvaddr)
{
int type = kmap_atomic_idx();
switch (type) {
case 0: __kunmap_atomic_primary(0, 6); break;
case 1: __kunmap_atomic_primary(0, 7); break;
case 2: __kunmap_atomic_primary(0, 8); break;
case 3: __kunmap_atomic_primary(0, 9); break;
case 4: __kunmap_atomic_primary(0, 10); break;
case 5 ... 5 + NR_TLB_LINES - 1:
__kunmap_atomic_secondary(type - 5, kvaddr);
break;
default:
BUG();
}
kmap_atomic_idx_pop();
pagefault_enable();
}
EXPORT_SYMBOL(__kunmap_atomic);