xref: /openbmc/linux/arch/arm/mm/copypage-v6.c (revision a09d2831)
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 
27 #define from_address	(0xffff8000)
28 #define to_address	(0xffffc000)
29 
30 static DEFINE_SPINLOCK(v6_lock);
31 
32 /*
33  * Copy the user page.  No aliasing to deal with so we can just
34  * attack the kernel's existing mapping of these pages.
35  */
36 static void v6_copy_user_highpage_nonaliasing(struct page *to,
37 	struct page *from, unsigned long vaddr)
38 {
39 	void *kto, *kfrom;
40 
41 	kfrom = kmap_atomic(from, KM_USER0);
42 	kto = kmap_atomic(to, KM_USER1);
43 	copy_page(kto, kfrom);
44 #ifdef CONFIG_HIGHMEM
45 	/*
46 	 * kmap_atomic() doesn't set the page virtual address, and
47 	 * kunmap_atomic() takes care of cache flushing already.
48 	 */
49 	if (page_address(to) != NULL)
50 #endif
51 		__cpuc_flush_dcache_area(kto, PAGE_SIZE);
52 	kunmap_atomic(kto, KM_USER1);
53 	kunmap_atomic(kfrom, KM_USER0);
54 }
55 
56 /*
57  * Clear the user page.  No aliasing to deal with so we can just
58  * attack the kernel's existing mapping of this page.
59  */
60 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
61 {
62 	void *kaddr = kmap_atomic(page, KM_USER0);
63 	clear_page(kaddr);
64 	kunmap_atomic(kaddr, KM_USER0);
65 }
66 
67 /*
68  * Discard data in the kernel mapping for the new page.
69  * FIXME: needs this MCRR to be supported.
70  */
71 static void discard_old_kernel_data(void *kto)
72 {
73 	__asm__("mcrr	p15, 0, %1, %0, c6	@ 0xec401f06"
74 	   :
75 	   : "r" (kto),
76 	     "r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
77 	   : "cc");
78 }
79 
80 /*
81  * Copy the page, taking account of the cache colour.
82  */
83 static void v6_copy_user_highpage_aliasing(struct page *to,
84 	struct page *from, unsigned long vaddr)
85 {
86 	unsigned int offset = CACHE_COLOUR(vaddr);
87 	unsigned long kfrom, kto;
88 
89 	if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
90 		__flush_dcache_page(page_mapping(from), from);
91 
92 	/* FIXME: not highmem safe */
93 	discard_old_kernel_data(page_address(to));
94 
95 	/*
96 	 * Now copy the page using the same cache colour as the
97 	 * pages ultimate destination.
98 	 */
99 	spin_lock(&v6_lock);
100 
101 	set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(page_to_pfn(from), PAGE_KERNEL), 0);
102 	set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(to), PAGE_KERNEL), 0);
103 
104 	kfrom = from_address + (offset << PAGE_SHIFT);
105 	kto   = to_address + (offset << PAGE_SHIFT);
106 
107 	flush_tlb_kernel_page(kfrom);
108 	flush_tlb_kernel_page(kto);
109 
110 	copy_page((void *)kto, (void *)kfrom);
111 
112 	spin_unlock(&v6_lock);
113 }
114 
115 /*
116  * Clear the user page.  We need to deal with the aliasing issues,
117  * so remap the kernel page into the same cache colour as the user
118  * page.
119  */
120 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
121 {
122 	unsigned int offset = CACHE_COLOUR(vaddr);
123 	unsigned long to = to_address + (offset << PAGE_SHIFT);
124 
125 	/* FIXME: not highmem safe */
126 	discard_old_kernel_data(page_address(page));
127 
128 	/*
129 	 * Now clear the page using the same cache colour as
130 	 * the pages ultimate destination.
131 	 */
132 	spin_lock(&v6_lock);
133 
134 	set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(page), PAGE_KERNEL), 0);
135 	flush_tlb_kernel_page(to);
136 	clear_page((void *)to);
137 
138 	spin_unlock(&v6_lock);
139 }
140 
141 struct cpu_user_fns v6_user_fns __initdata = {
142 	.cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
143 	.cpu_copy_user_highpage	= v6_copy_user_highpage_nonaliasing,
144 };
145 
146 static int __init v6_userpage_init(void)
147 {
148 	if (cache_is_vipt_aliasing()) {
149 		cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
150 		cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
151 	}
152 
153 	return 0;
154 }
155 
156 core_initcall(v6_userpage_init);
157