1 /*
2 * highmem.h: virtual kernel memory mappings for high memory
3 *
4 * Used in CONFIG_HIGHMEM systems for memory pages which
5 * are not addressable by direct kernel virtual addresses.
6 *
7 * Copyright (C) 1999 Gerhard Wichert, Siemens AG
8 * Gerhard.Wichert@pdb.siemens.de
9 *
10 *
11 * Redesigned the x86 32-bit VM architecture to deal with
12 * up to 16 Terabyte physical memory. With current x86 CPUs
13 * we now support up to 64 Gigabytes physical RAM.
14 *
15 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
16 */
17
18 #ifndef _ASM_HIGHMEM_H
19 #define _ASM_HIGHMEM_H
20
21 #ifdef __KERNEL__
22
23 #include <linux/interrupt.h>
24 #include <linux/threads.h>
25 #include <asm/kmap_types.h>
26 #include <asm/tlbflush.h>
27 #include <asm/paravirt.h>
28
29 /* declarations for highmem.c */
30 extern unsigned long highstart_pfn, highend_pfn;
31
32 extern pte_t *kmap_pte;
33 extern pgprot_t kmap_prot;
34 extern pte_t *pkmap_page_table;
35
36 /*
37 * Right now we initialize only a single pte table. It can be extended
38 * easily, subsequent pte tables have to be allocated in one physical
39 * chunk of RAM.
40 */
41 /*
42 * Ordering is:
43 *
44 * FIXADDR_TOP
45 * fixed_addresses
46 * FIXADDR_START
47 * temp fixed addresses
48 * FIXADDR_BOOT_START
49 * Persistent kmap area
50 * PKMAP_BASE
51 * VMALLOC_END
52 * Vmalloc area
53 * VMALLOC_START
54 * high_memory
55 */
56 #define LAST_PKMAP_MASK (LAST_PKMAP-1)
57 #define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
58 #define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
59
60 extern void *kmap_high(struct page *page);
61 extern void kunmap_high(struct page *page);
62
63 void *kmap(struct page *page);
64 extern void kunmap_virt(void *ptr);
65 extern struct page *kmap_to_page(void *ptr);
66 void kunmap(struct page *page);
67
68 void *__kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot);
69 void *__kmap_atomic(struct page *page, enum km_type type);
70 void __kunmap_atomic(void *kvaddr, enum km_type type);
71 void *__kmap_atomic_pfn(unsigned long pfn, enum km_type type);
72 struct page *__kmap_atomic_to_page(void *ptr);
73
74 void kunmap(struct page *page);
75 void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot);
76 void *kmap_atomic(struct page *page, enum km_type type);
77 void kunmap_atomic(void *kvaddr, enum km_type type);
78 void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
79 struct page *kmap_atomic_to_page(void *ptr);
80
81 #ifndef CONFIG_PARAVIRT
82 #define kmap_atomic_pte(page, type) kmap_atomic(page, type)
83 #endif
84
85 #define flush_cache_kmaps() do { } while (0)
86
87 /*
88 * on PREEMPT_RT kmap_atomic() is a wrapper that uses kmap():
89 */
90 #ifdef CONFIG_PREEMPT_RT
91 # define kmap_atomic_prot(page, type, prot) ({ pagefault_disable(); kmap(page); })
92 # define kmap_atomic(page, type) ({ pagefault_disable(); kmap(page); })
93 # define kmap_atomic_pfn(pfn, type) kmap(pfn_to_page(pfn))
94 # define kunmap_atomic(kvaddr, type) do { pagefault_enable(); kunmap_virt(kvaddr); } while(0)
95 # define kmap_atomic_to_page(kvaddr) kmap_to_page(kvaddr)
96 #else
97 # define kmap_atomic_prot(page, type, prot) __kmap_atomic_prot(page, type, prot)
98 # define kmap_atomic(page, type) __kmap_atomic(page, type)
99 # define kmap_atomic_pfn(pfn, type) __kmap_atomic_pfn(pfn, type)
100 # define kunmap_atomic(kvaddr, type) __kunmap_atomic(kvaddr, type)
101 # define kmap_atomic_to_page(kvaddr) __kmap_atomic_to_page(kvaddr)
102 #endif
103
104 #endif /* __KERNEL__ */
105
106 #endif /* _ASM_HIGHMEM_H */
107
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