80 lines
2 KiB
C
80 lines
2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* highmem.h: virtual kernel memory mappings for high memory
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*
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* Used in CONFIG_HIGHMEM systems for memory pages which
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* are not addressable by direct kernel virtual addresses.
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*
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* Copyright (C) 1999 Gerhard Wichert, Siemens AG
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* Gerhard.Wichert@pdb.siemens.de
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*
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*
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* Redesigned the x86 32-bit VM architecture to deal with
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* up to 16 Terrabyte physical memory. With current x86 CPUs
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* we now support up to 64 Gigabytes physical RAM.
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*
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* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
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*/
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#ifndef _ASM_HIGHMEM_H
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#define _ASM_HIGHMEM_H
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#ifdef __KERNEL__
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#include <linux/interrupt.h>
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#include <asm/vaddrs.h>
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#include <asm/kmap_types.h>
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#include <asm/pgtable.h>
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/* declarations for highmem.c */
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extern unsigned long highstart_pfn, highend_pfn;
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extern pgprot_t kmap_prot;
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extern pte_t *pkmap_page_table;
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void kmap_init(void) __init;
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/*
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* Right now we initialize only a single pte table. It can be extended
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* easily, subsequent pte tables have to be allocated in one physical
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* chunk of RAM. Currently the simplest way to do this is to align the
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* pkmap region on a pagetable boundary (4MB).
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*/
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#define LAST_PKMAP 1024
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#define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT)
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#define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT))
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#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
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#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
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#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
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#define PKMAP_END (PKMAP_ADDR(LAST_PKMAP))
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void *kmap_high(struct page *page);
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void kunmap_high(struct page *page);
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static inline void *kmap(struct page *page)
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{
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BUG_ON(in_interrupt());
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if (!PageHighMem(page))
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return page_address(page);
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return kmap_high(page);
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}
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static inline void kunmap(struct page *page)
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{
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BUG_ON(in_interrupt());
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if (!PageHighMem(page))
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return;
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kunmap_high(page);
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}
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void *kmap_atomic(struct page *page);
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void __kunmap_atomic(void *kvaddr);
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#define flush_cache_kmaps() flush_cache_all()
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#endif /* __KERNEL__ */
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#endif /* _ASM_HIGHMEM_H */
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