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/init.h>
24 #include <linux/interrupt.h>
25 #include <linux/uaccess.h>
26 #include <asm/fixmap.h>
27
28 extern pte_t *pkmap_page_table;
29
30 /*
31 * Right now we initialize only a single pte table. It can be extended
32 * easily, subsequent pte tables have to be allocated in one physical
33 * chunk of RAM.
34 */
35 /*
36 * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
37 * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
38 * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
39 * in case of 16K/64K/256K page sizes.
40 */
41
42 #define PKMAP_ORDER PTE_SHIFT
43 #define LAST_PKMAP (1 << PKMAP_ORDER)
44
45 #define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
46 & PMD_MASK)
47
48 #define LAST_PKMAP_MASK (LAST_PKMAP - 1)
49 #define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
50 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
51
52 #define flush_cache_kmaps() { flush_icache(); flush_dcache(); }
53
54 #define arch_kmap_local_post_map(vaddr, pteval) \
55 local_flush_tlb_page(NULL, vaddr);
56 #define arch_kmap_local_post_unmap(vaddr) \
57 local_flush_tlb_page(NULL, vaddr);
58
59 #endif /* __KERNEL__ */
60
61 #endif /* _ASM_HIGHMEM_H */
62
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