ARM: 7090/1: CACHE-L2X0: filter start address can be 0 and is often 0
[linux-3.10.git] / arch / arm / mm / copypage-v6.c
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, struct vm_area_struct *vma)
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         kunmap_atomic(kto, KM_USER1);
45         kunmap_atomic(kfrom, KM_USER0);
46 }
47
48 /*
49  * Clear the user page.  No aliasing to deal with so we can just
50  * attack the kernel's existing mapping of this page.
51  */
52 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
53 {
54         void *kaddr = kmap_atomic(page, KM_USER0);
55         clear_page(kaddr);
56         kunmap_atomic(kaddr, KM_USER0);
57 }
58
59 /*
60  * Discard data in the kernel mapping for the new page.
61  * FIXME: needs this MCRR to be supported.
62  */
63 static void discard_old_kernel_data(void *kto)
64 {
65         __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
66            :
67            : "r" (kto),
68              "r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
69            : "cc");
70 }
71
72 /*
73  * Copy the page, taking account of the cache colour.
74  */
75 static void v6_copy_user_highpage_aliasing(struct page *to,
76         struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
77 {
78         unsigned int offset = CACHE_COLOUR(vaddr);
79         unsigned long kfrom, kto;
80
81         if (!test_and_set_bit(PG_dcache_clean, &from->flags))
82                 __flush_dcache_page(page_mapping(from), from);
83
84         /* FIXME: not highmem safe */
85         discard_old_kernel_data(page_address(to));
86
87         /*
88          * Now copy the page using the same cache colour as the
89          * pages ultimate destination.
90          */
91         spin_lock(&v6_lock);
92
93         set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(page_to_pfn(from), PAGE_KERNEL), 0);
94         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(to), PAGE_KERNEL), 0);
95
96         kfrom = from_address + (offset << PAGE_SHIFT);
97         kto   = to_address + (offset << PAGE_SHIFT);
98
99         flush_tlb_kernel_page(kfrom);
100         flush_tlb_kernel_page(kto);
101
102         copy_page((void *)kto, (void *)kfrom);
103
104         spin_unlock(&v6_lock);
105 }
106
107 /*
108  * Clear the user page.  We need to deal with the aliasing issues,
109  * so remap the kernel page into the same cache colour as the user
110  * page.
111  */
112 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
113 {
114         unsigned int offset = CACHE_COLOUR(vaddr);
115         unsigned long to = to_address + (offset << PAGE_SHIFT);
116
117         /* FIXME: not highmem safe */
118         discard_old_kernel_data(page_address(page));
119
120         /*
121          * Now clear the page using the same cache colour as
122          * the pages ultimate destination.
123          */
124         spin_lock(&v6_lock);
125
126         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(page), PAGE_KERNEL), 0);
127         flush_tlb_kernel_page(to);
128         clear_page((void *)to);
129
130         spin_unlock(&v6_lock);
131 }
132
133 struct cpu_user_fns v6_user_fns __initdata = {
134         .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
135         .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
136 };
137
138 static int __init v6_userpage_init(void)
139 {
140         if (cache_is_vipt_aliasing()) {
141                 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
142                 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
143         }
144
145         return 0;
146 }
147
148 core_initcall(v6_userpage_init);