Viewing file:  highmem.h (3.01 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/* MN10300 Virtual kernel memory mappings for high memory
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from include/asm-i386/highmem.h
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#ifndef _ASM_HIGHMEM_H
#define _ASM_HIGHMEM_H
#ifdef __KERNEL__
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/highmem.h>
#include <asm/kmap_types.h>
#include <asm/pgtable.h>
/* undef for production */
#undef HIGHMEM_DEBUG
/* 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;
extern void __init kmap_init(void);
/*
* 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 unsigned long kmap_high(struct page *page);
extern void kunmap_high(struct page *page);
static inline unsigned long kmap(struct page *page)
{
if (in_interrupt())
BUG();
if (page < highmem_start_page)
return page_address(page);
return kmap_high(page);
}
static inline void kunmap(struct page *page)
{
if (in_interrupt())
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)
{
unsigned long vaddr;
int idx, type;
preempt_disable();
pagefault_disable();
if (page < highmem_start_page)
return page_address(page);
type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR * smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#if HIGHMEM_DEBUG
if (!pte_none(*(kmap_pte - idx)))
BUG();
#endif
set_pte(kmap_pte - idx, mk_pte(page, kmap_prot));
local_flush_tlb_one(vaddr);
return (void *)vaddr;
}
static inline void __kunmap_atomic(unsigned long vaddr)
{
int type;
if (vaddr < FIXADDR_START) { /* FIXME */
pagefault_enable();
preempt_enable();
return;
}
type = kmap_atomic_idx();
#if HIGHMEM_DEBUG
{
unsigned int idx;
idx = type + KM_TYPE_NR * smp_processor_id();
if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
BUG();
/*
* force other mappings to Oops if they'll try to access
* this pte without first remap it
*/
pte_clear(kmap_pte - idx);
local_flush_tlb_one(vaddr);
}
#endif
kmap_atomic_idx_pop();
pagefault_enable();
preempt_enable();
}
#endif /* __KERNEL__ */
#endif /* _ASM_HIGHMEM_H */
|