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 Terrabyte 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_HIGHMEM_H
20 #define _ASM_HIGHMEM_H
21 
22 #ifdef __KERNEL__
23 
24 #include <linux/interrupt.h>
25 #include <linux/pgtable.h>
26 #include <asm/vaddrs.h>
27 #include <asm/pgtsrmmu.h>
28 
29 /* declarations for highmem.c */
30 extern unsigned long highstart_pfn, highend_pfn;
31 
32 #define kmap_prot __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE)
33 extern pte_t *pkmap_page_table;
34 
35 /*
36  * Right now we initialize only a single pte table. It can be extended
37  * easily, subsequent pte tables have to be allocated in one physical
38  * chunk of RAM.  Currently the simplest way to do this is to align the
39  * pkmap region on a pagetable boundary (4MB).
40  */
41 #define LAST_PKMAP 1024
42 #define PKMAP_SIZE (LAST_PKMAP << PAGE_SHIFT)
43 #define PKMAP_BASE PMD_ALIGN(SRMMU_NOCACHE_VADDR + (SRMMU_MAX_NOCACHE_PAGES << PAGE_SHIFT))
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 
49 #define PKMAP_END (PKMAP_ADDR(LAST_PKMAP))
50 
51 #define flush_cache_kmaps()	flush_cache_all()
52 
53 /* FIXME: Use __flush_*_one(vaddr) instead of flush_*_all() -- Anton */
54 #define arch_kmap_local_pre_map(vaddr, pteval)	flush_cache_all()
55 #define arch_kmap_local_pre_unmap(vaddr)	flush_cache_all()
56 #define arch_kmap_local_post_map(vaddr, pteval)	flush_tlb_all()
57 #define arch_kmap_local_post_unmap(vaddr)	flush_tlb_all()
58 
59 #endif /* __KERNEL__ */
60 
61 #endif /* _ASM_HIGHMEM_H */
62