1/*
2 *  linux/arch/arm/mm/copypage-v6.c
3 *
4 *  Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/init.h>
11#include <linux/spinlock.h>
12#include <linux/mm.h>
13#include <linux/highmem.h>
14
15#include <asm/pgtable.h>
16#include <asm/shmparam.h>
17#include <asm/tlbflush.h>
18#include <asm/cacheflush.h>
19#include <asm/cachetype.h>
20
21#include "mm.h"
22
23#if SHMLBA > 16384
24#error FIX ME
25#endif
26
27static DEFINE_RAW_SPINLOCK(v6_lock);
28
29/*
30 * Copy the user page.  No aliasing to deal with so we can just
31 * attack the kernel's existing mapping of these pages.
32 */
33static void v6_copy_user_highpage_nonaliasing(struct page *to,
34	struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
35{
36	void *kto, *kfrom;
37
38	kfrom = kmap_atomic(from);
39	kto = kmap_atomic(to);
40	copy_page(kto, kfrom);
41	kunmap_atomic(kto);
42	kunmap_atomic(kfrom);
43}
44
45/*
46 * Clear the user page.  No aliasing to deal with so we can just
47 * attack the kernel's existing mapping of this page.
48 */
49static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
50{
51	void *kaddr = kmap_atomic(page);
52	clear_page(kaddr);
53	kunmap_atomic(kaddr);
54}
55
56/*
57 * Discard data in the kernel mapping for the new page.
58 * FIXME: needs this MCRR to be supported.
59 */
60static void discard_old_kernel_data(void *kto)
61{
62	__asm__("mcrr	p15, 0, %1, %0, c6	@ 0xec401f06"
63	   :
64	   : "r" (kto),
65	     "r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
66	   : "cc");
67}
68
69/*
70 * Copy the page, taking account of the cache colour.
71 */
72static void v6_copy_user_highpage_aliasing(struct page *to,
73	struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
74{
75	unsigned int offset = CACHE_COLOUR(vaddr);
76	unsigned long kfrom, kto;
77
78	if (!test_and_set_bit(PG_dcache_clean, &from->flags))
79		__flush_dcache_page(page_mapping(from), from);
80
81	/* FIXME: not highmem safe */
82	discard_old_kernel_data(page_address(to));
83
84	/*
85	 * Now copy the page using the same cache colour as the
86	 * pages ultimate destination.
87	 */
88	raw_spin_lock(&v6_lock);
89
90	kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
91	kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
92
93	set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
94	set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
95
96	copy_page((void *)kto, (void *)kfrom);
97
98	raw_spin_unlock(&v6_lock);
99}
100
101/*
102 * Clear the user page.  We need to deal with the aliasing issues,
103 * so remap the kernel page into the same cache colour as the user
104 * page.
105 */
106static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
107{
108	unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
109
110	/* FIXME: not highmem safe */
111	discard_old_kernel_data(page_address(page));
112
113	/*
114	 * Now clear the page using the same cache colour as
115	 * the pages ultimate destination.
116	 */
117	raw_spin_lock(&v6_lock);
118
119	set_top_pte(to, mk_pte(page, PAGE_KERNEL));
120	clear_page((void *)to);
121
122	raw_spin_unlock(&v6_lock);
123}
124
125struct cpu_user_fns v6_user_fns __initdata = {
126	.cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
127	.cpu_copy_user_highpage	= v6_copy_user_highpage_nonaliasing,
128};
129
130static int __init v6_userpage_init(void)
131{
132	if (cache_is_vipt_aliasing()) {
133		cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
134		cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
135	}
136
137	return 0;
138}
139
140core_initcall(v6_userpage_init);
141