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
19 #ifndef _ASM_X86_HIGHMEM_H
20 #define _ASM_X86_HIGHMEM_H
21
22 #ifdef __KERNEL__
23
24 #include <linux/interrupt.h>
25 #include <linux/threads.h>
26 #include <asm/kmap_types.h>
27 #include <asm/tlbflush.h>
28 #include <asm/paravirt.h>
29 #include <asm/fixmap.h>
30
31 /* declarations for highmem.c */
32 extern unsigned long highstart_pfn, highend_pfn;
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 /*
40 * Ordering is:
41 *
42 * high memory on: high_memory off:
43 * FIXADDR_TOP FIXADDR_TOP
44 * fixed addresses fixed addresses
45 * FIXADDR_START FIXADDR_START
46 * temp fixed addresses/persistent kmap area VMALLOC_END
47 * PKMAP_BASE temp fixed addresses/vmalloc area
48 * VMALLOC_END VMALLOC_START
49 * vmalloc area high_memory
50 * VMALLOC_START
51 * high_memory
52 *
53 * The temp fixed area is only used during boot for early_ioremap(), and
54 * it is unused when the ioremap() is functional. vmalloc/pkmap area become
55 * available after early boot so the temp fixed area is available for re-use.
56 */
57 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
58 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
59 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
60
61 extern void *kmap_high(struct page *page);
62 extern void kunmap_high(struct page *page);
63
64 void *kmap(struct page *page);
65 void kunmap(struct page *page);
66
67 void *kmap_atomic_prot(struct page *page, pgprot_t prot);
68 void *kmap_atomic(struct page *page);
69 void __kunmap_atomic(void *kvaddr);
70 void *kmap_atomic_pfn(unsigned long pfn);
71 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
72
73 #define flush_cache_kmaps() do { } while (0)
74
75 extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
76 unsigned long end_pfn);
77
78 #endif /* __KERNEL__ */
79
80 #endif /* _ASM_X86_HIGHMEM_H */