105 lines
2.8 KiB
C
105 lines
2.8 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 <asm/kmap_types.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);
|
|
extern void kunmap_high(struct page *page);
|
|
|
|
/*
|
|
* CONFIG_LIMITED_DMA is for systems with DMA limitations such as Momentum's
|
|
* Jaguar ATX. This option exploits the highmem code in the kernel so is
|
|
* always enabled together with CONFIG_HIGHMEM but at this time doesn't
|
|
* actually add highmem functionality.
|
|
*/
|
|
|
|
#ifdef CONFIG_LIMITED_DMA
|
|
|
|
/*
|
|
* These are the default functions for the no-highmem case from
|
|
* <linux/highmem.h>
|
|
*/
|
|
static inline void *kmap(struct page *page)
|
|
{
|
|
might_sleep();
|
|
return page_address(page);
|
|
}
|
|
|
|
#define kunmap(page) do { (void) (page); } while (0)
|
|
|
|
static inline void *kmap_atomic(struct page *page, enum km_type type)
|
|
{
|
|
return page_address(page);
|
|
}
|
|
|
|
static inline void kunmap_atomic(void *kvaddr, enum km_type type) { }
|
|
#define kmap_atomic_pfn(pfn, idx) page_address(pfn_to_page(pfn))
|
|
|
|
#define kmap_atomic_to_page(ptr) virt_to_page(ptr)
|
|
|
|
#define flush_cache_kmaps() do { } while (0)
|
|
|
|
#else /* LIMITED_DMA */
|
|
|
|
extern void *__kmap(struct page *page);
|
|
extern void __kunmap(struct page *page);
|
|
extern void *__kmap_atomic(struct page *page, enum km_type type);
|
|
extern void __kunmap_atomic(void *kvaddr, enum km_type type);
|
|
extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
|
|
extern struct page *__kmap_atomic_to_page(void *ptr);
|
|
|
|
#define kmap __kmap
|
|
#define kunmap __kunmap
|
|
#define kmap_atomic __kmap_atomic
|
|
#define kunmap_atomic __kunmap_atomic
|
|
#define kmap_atomic_to_page __kmap_atomic_to_page
|
|
|
|
#define flush_cache_kmaps() flush_cache_all()
|
|
|
|
#endif /* LIMITED_DMA */
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif /* _ASM_HIGHMEM_H */
|