mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-04 01:24:12 +08:00
97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/*
|
|
* 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 <linux/uaccess.h>
|
|
#include <asm/fixmap.h>
|
|
|
|
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.
|
|
*/
|
|
/*
|
|
* We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
|
|
* table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
|
|
* and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
|
|
* in case of 16K/64K/256K page sizes.
|
|
*/
|
|
|
|
#define PKMAP_ORDER PTE_SHIFT
|
|
#define LAST_PKMAP (1 << PKMAP_ORDER)
|
|
|
|
#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
|
|
& PMD_MASK)
|
|
|
|
#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);
|
|
extern void kunmap_high(struct page *page);
|
|
extern void *kmap_atomic_prot(struct page *page, pgprot_t prot);
|
|
extern void __kunmap_atomic(void *kvaddr);
|
|
|
|
static inline void *kmap(struct page *page)
|
|
{
|
|
might_sleep();
|
|
if (!PageHighMem(page))
|
|
return page_address(page);
|
|
return kmap_high(page);
|
|
}
|
|
|
|
static inline void kunmap(struct page *page)
|
|
{
|
|
BUG_ON(in_interrupt());
|
|
if (!PageHighMem(page))
|
|
return;
|
|
kunmap_high(page);
|
|
}
|
|
|
|
static inline void *__kmap_atomic(struct page *page)
|
|
{
|
|
return kmap_atomic_prot(page, kmap_prot);
|
|
}
|
|
|
|
static inline 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);
|
|
}
|
|
|
|
#define flush_cache_kmaps() { flush_icache(); flush_dcache(); }
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif /* _ASM_HIGHMEM_H */
|