| /* |
| * 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 Terrabyte 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/interrupt.h> |
| #include <asm/kmap_types.h> |
| |
| /* undef for production */ |
| #define HIGHMEM_DEBUG 1 |
| |
| /* in mm/highmem.c */ |
| extern void *kmap_high(struct page *page, int nonblocking); |
| extern void kunmap_high(struct page *page); |
| |
| /* 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; |
| |
| /* This gets set in {srmmu,sun4c}_paging_init() */ |
| extern unsigned long fix_kmap_begin; |
| |
| /* Only used and set with srmmu? */ |
| extern unsigned long pkmap_base; |
| |
| extern void kmap_init(void) __init; |
| |
| /* |
| * 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 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)) |
| |
| /* in arch/sparc/mm/highmem.c */ |
| void *kmap_atomic(struct page *page, enum km_type type); |
| void kunmap_atomic(void *kvaddr, enum km_type type); |
| |
| #define kmap(page) __kmap(page, 0) |
| #define kmap_nonblock(page) __kmap(page, 1) |
| |
| static inline void *__kmap(struct page *page, int nonblocking) |
| { |
| if (in_interrupt()) |
| BUG(); |
| if (page < highmem_start_page) |
| return page_address(page); |
| return kmap_high(page, nonblocking); |
| } |
| |
| static inline void kunmap(struct page *page) |
| { |
| if (in_interrupt()) |
| BUG(); |
| if (page < highmem_start_page) |
| return; |
| kunmap_high(page); |
| } |
| |
| #endif /* __KERNEL__ */ |
| |
| #endif /* _ASM_HIGHMEM_H */ |