1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/arm/mm/copypage-v6.c
4 *
5 * Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
6 */
7 #include <linux/init.h>
8 #include <linux/spinlock.h>
9 #include <linux/mm.h>
10 #include <linux/highmem.h>
11 #include <linux/pagemap.h>
12
13 #include <asm/shmparam.h>
14 #include <asm/tlbflush.h>
15 #include <asm/cacheflush.h>
16 #include <asm/cachetype.h>
17
18 #include "mm.h"
19
20 #if SHMLBA > 16384
21 #error FIX ME
22 #endif
23
24 static DEFINE_RAW_SPINLOCK(v6_lock);
25
26 /*
27 * Copy the user page. No aliasing to deal with so we can just
28 * attack the kernel's existing mapping of these pages.
29 */
30 static void v6_copy_user_highpage_nonaliasing(struct page *to,
31 struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
32 {
33 void *kto, *kfrom;
34
35 kfrom = kmap_atomic(from);
36 kto = kmap_atomic(to);
37 copy_page(kto, kfrom);
38 kunmap_atomic(kto);
39 kunmap_atomic(kfrom);
40 }
41
42 /*
43 * Clear the user page. No aliasing to deal with so we can just
44 * attack the kernel's existing mapping of this page.
45 */
46 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
47 {
48 void *kaddr = kmap_atomic(page);
49 clear_page(kaddr);
50 kunmap_atomic(kaddr);
51 }
52
53 /*
54 * Discard data in the kernel mapping for the new page.
55 * FIXME: needs this MCRR to be supported.
56 */
57 static void discard_old_kernel_data(void *kto)
58 {
59 __asm__("mcrr p15, 0, %1, %0, c6 @ 0xec401f06"
60 :
61 : "r" (kto),
62 "r" ((unsigned long)kto + PAGE_SIZE - 1)
63 : "cc");
64 }
65
66 /*
67 * Copy the page, taking account of the cache colour.
68 */
69 static void v6_copy_user_highpage_aliasing(struct page *to,
70 struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
71 {
72 struct folio *src = page_folio(from);
73 unsigned int offset = CACHE_COLOUR(vaddr);
74 unsigned long kfrom, kto;
75
76 if (!test_and_set_bit(PG_dcache_clean, &src->flags))
77 __flush_dcache_folio(folio_flush_mapping(src), src);
78
79 /* FIXME: not highmem safe */
80 discard_old_kernel_data(page_address(to));
81
82 /*
83 * Now copy the page using the same cache colour as the
84 * pages ultimate destination.
85 */
86 raw_spin_lock(&v6_lock);
87
88 kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
89 kto = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
90
91 set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
92 set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
93
94 copy_page((void *)kto, (void *)kfrom);
95
96 raw_spin_unlock(&v6_lock);
97 }
98
99 /*
100 * Clear the user page. We need to deal with the aliasing issues,
101 * so remap the kernel page into the same cache colour as the user
102 * page.
103 */
104 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
105 {
106 unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
107
108 /* FIXME: not highmem safe */
109 discard_old_kernel_data(page_address(page));
110
111 /*
112 * Now clear the page using the same cache colour as
113 * the pages ultimate destination.
114 */
115 raw_spin_lock(&v6_lock);
116
117 set_top_pte(to, mk_pte(page, PAGE_KERNEL));
118 clear_page((void *)to);
119
120 raw_spin_unlock(&v6_lock);
121 }
122
123 struct cpu_user_fns v6_user_fns __initdata = {
124 .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
125 .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
126 };
127
128 static int __init v6_userpage_init(void)
129 {
130 if (cache_is_vipt_aliasing()) {
131 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
132 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
133 }
134
135 return 0;
136 }
137
138 core_initcall(v6_userpage_init);
139
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