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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * highmem.h: virtual kernel memory mappings for high memory
4 *
5 * Used in CONFIG_HIGHMEM systems for memory pages which
6 * are not addressable by direct kernel virtual addresses.
7 *
8 * Copyright (C) 1999 Gerhard Wichert, Siemens AG
9 * Gerhard.Wichert@pdb.siemens.de
10 *
11 *
12 * Redesigned the x86 32-bit VM architecture to deal with
13 * up to 16 Terabyte physical memory. With current x86 CPUs
14 * we now support up to 64 Gigabytes physical RAM.
15 *
16 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
17 */
18#ifndef _ASM_HIGHMEM_H
19#define _ASM_HIGHMEM_H
20
21#ifdef __KERNEL__
22
23#include <linux/bug.h>
24#include <linux/interrupt.h>
25#include <linux/uaccess.h>
26#include <asm/cpu-features.h>
27#include <asm/kmap_types.h>
28
29/* declarations for highmem.c */
30extern unsigned long highstart_pfn, highend_pfn;
31
32extern pte_t *pkmap_page_table;
33
34/*
35 * Right now we initialize only a single pte table. It can be extended
36 * easily, subsequent pte tables have to be allocated in one physical
37 * chunk of RAM.
38 */
39#ifdef CONFIG_PHYS_ADDR_T_64BIT
40#define LAST_PKMAP 512
41#else
42#define LAST_PKMAP 1024
43#endif
44
45#define LAST_PKMAP_MASK (LAST_PKMAP-1)
46#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
47#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
48
49extern void * kmap_high(struct page *page);
50extern void kunmap_high(struct page *page);
51
52extern void *kmap(struct page *page);
53extern void kunmap(struct page *page);
54extern void *kmap_atomic(struct page *page);
55extern void __kunmap_atomic(void *kvaddr);
56extern void *kmap_atomic_pfn(unsigned long pfn);
57
58#define flush_cache_kmaps() BUG_ON(cpu_has_dc_aliases)
59
60extern void kmap_init(void);
61
62#define kmap_prot PAGE_KERNEL
63
64#endif /* __KERNEL__ */
65
66#endif /* _ASM_HIGHMEM_H */