1/* MN10300 Virtual kernel memory mappings for high memory
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 * - Derived from include/asm-i386/highmem.h
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
11 */
12#ifndef _ASM_HIGHMEM_H
13#define _ASM_HIGHMEM_H
14
15#ifdef __KERNEL__
16
17#include <linux/init.h>
18#include <linux/interrupt.h>
19#include <linux/highmem.h>
20#include <asm/kmap_types.h>
21#include <asm/pgtable.h>
22
23/* undef for production */
24#undef HIGHMEM_DEBUG
25
26/* declarations for highmem.c */
27extern unsigned long highstart_pfn, highend_pfn;
28
29extern pte_t *kmap_pte;
30extern pgprot_t kmap_prot;
31extern pte_t *pkmap_page_table;
32
33extern void __init kmap_init(void);
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.
39 */
40#define PKMAP_BASE	0xfe000000UL
41#define LAST_PKMAP	1024
42#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
43#define PKMAP_NR(virt)  ((virt - PKMAP_BASE) >> PAGE_SHIFT)
44#define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
45
46extern unsigned long kmap_high(struct page *page);
47extern void kunmap_high(struct page *page);
48
49static inline unsigned long kmap(struct page *page)
50{
51	if (in_interrupt())
52		BUG();
53	if (page < highmem_start_page)
54		return page_address(page);
55	return kmap_high(page);
56}
57
58static inline void kunmap(struct page *page)
59{
60	if (in_interrupt())
61		BUG();
62	if (page < highmem_start_page)
63		return;
64	kunmap_high(page);
65}
66
67/*
68 * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
69 * gives a more generic (and caching) interface. But kmap_atomic can
70 * be used in IRQ contexts, so in some (very limited) cases we need
71 * it.
72 */
73static inline void *kmap_atomic(struct page *page)
74{
75	unsigned long vaddr;
76	int idx, type;
77
78	pagefault_disable();
79	if (page < highmem_start_page)
80		return page_address(page);
81
82	type = kmap_atomic_idx_push();
83	idx = type + KM_TYPE_NR * smp_processor_id();
84	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
85#if HIGHMEM_DEBUG
86	if (!pte_none(*(kmap_pte - idx)))
87		BUG();
88#endif
89	set_pte(kmap_pte - idx, mk_pte(page, kmap_prot));
90	local_flush_tlb_one(vaddr);
91
92	return (void *)vaddr;
93}
94
95static inline void __kunmap_atomic(unsigned long vaddr)
96{
97	int type;
98
99	if (vaddr < FIXADDR_START) { /* FIXME */
100		pagefault_enable();
101		return;
102	}
103
104	type = kmap_atomic_idx();
105
106#if HIGHMEM_DEBUG
107	{
108		unsigned int idx;
109		idx = type + KM_TYPE_NR * smp_processor_id();
110
111		if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
112			BUG();
113
114		/*
115		 * force other mappings to Oops if they'll try to access
116		 * this pte without first remap it
117		 */
118		pte_clear(kmap_pte - idx);
119		local_flush_tlb_one(vaddr);
120	}
121#endif
122
123	kmap_atomic_idx_pop();
124	pagefault_enable();
125}
126#endif /* __KERNEL__ */
127
128#endif /* _ASM_HIGHMEM_H */
129