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f8f98a93 RK |
1 | /* |
2 | * linux/arch/arm/lib/copypage-xscale.S | |
3 | * | |
4 | * Copyright (C) 1995-2005 Russell King | |
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 | * This handles the mini data cache, as found on SA11x0 and XScale | |
11 | * processors. When we copy a user page page, we map it in such a way | |
12 | * that accesses to this page will not touch the main data cache, but | |
13 | * will be cached in the mini data cache. This prevents us thrashing | |
14 | * the main data cache on page faults. | |
15 | */ | |
16 | #include <linux/init.h> | |
17 | #include <linux/mm.h> | |
18 | ||
19 | #include <asm/page.h> | |
20 | #include <asm/pgtable.h> | |
21 | #include <asm/tlbflush.h> | |
1c9d3df5 | 22 | #include <asm/cacheflush.h> |
f8f98a93 | 23 | |
1b2e2b73 RK |
24 | #include "mm.h" |
25 | ||
f8f98a93 RK |
26 | /* |
27 | * 0xffff8000 to 0xffffffff is reserved for any ARM architecture | |
28 | * specific hacks for copying pages efficiently. | |
29 | */ | |
30 | #define COPYPAGE_MINICACHE 0xffff8000 | |
31 | ||
32 | #define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \ | |
33 | L_PTE_CACHEABLE) | |
34 | ||
f8f98a93 RK |
35 | static DEFINE_SPINLOCK(minicache_lock); |
36 | ||
37 | /* | |
38 | * XScale mini-dcache optimised copy_user_page | |
39 | * | |
40 | * We flush the destination cache lines just before we write the data into the | |
41 | * corresponding address. Since the Dcache is read-allocate, this removes the | |
42 | * Dcache aliasing issue. The writes will be forwarded to the write buffer, | |
43 | * and merged as appropriate. | |
44 | */ | |
45 | static void __attribute__((naked)) | |
46 | mc_copy_user_page(void *from, void *to) | |
47 | { | |
48 | /* | |
49 | * Strangely enough, best performance is achieved | |
50 | * when prefetching destination as well. (NP) | |
51 | */ | |
52 | asm volatile( | |
53 | "stmfd sp!, {r4, r5, lr} \n\ | |
54 | mov lr, %2 \n\ | |
55 | pld [r0, #0] \n\ | |
56 | pld [r0, #32] \n\ | |
57 | pld [r1, #0] \n\ | |
58 | pld [r1, #32] \n\ | |
59 | 1: pld [r0, #64] \n\ | |
60 | pld [r0, #96] \n\ | |
61 | pld [r1, #64] \n\ | |
62 | pld [r1, #96] \n\ | |
63 | 2: ldrd r2, [r0], #8 \n\ | |
64 | ldrd r4, [r0], #8 \n\ | |
65 | mov ip, r1 \n\ | |
66 | strd r2, [r1], #8 \n\ | |
67 | ldrd r2, [r0], #8 \n\ | |
68 | strd r4, [r1], #8 \n\ | |
69 | ldrd r4, [r0], #8 \n\ | |
70 | strd r2, [r1], #8 \n\ | |
71 | strd r4, [r1], #8 \n\ | |
72 | mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ | |
73 | ldrd r2, [r0], #8 \n\ | |
74 | mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ | |
75 | ldrd r4, [r0], #8 \n\ | |
76 | mov ip, r1 \n\ | |
77 | strd r2, [r1], #8 \n\ | |
78 | ldrd r2, [r0], #8 \n\ | |
79 | strd r4, [r1], #8 \n\ | |
80 | ldrd r4, [r0], #8 \n\ | |
81 | strd r2, [r1], #8 \n\ | |
82 | strd r4, [r1], #8 \n\ | |
83 | mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ | |
84 | subs lr, lr, #1 \n\ | |
85 | mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ | |
86 | bgt 1b \n\ | |
87 | beq 2b \n\ | |
88 | ldmfd sp!, {r4, r5, pc} " | |
89 | : | |
90 | : "r" (from), "r" (to), "I" (PAGE_SIZE / 64 - 1)); | |
91 | } | |
92 | ||
93 | void xscale_mc_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr) | |
94 | { | |
1c9d3df5 RP |
95 | struct page *page = virt_to_page(kfrom); |
96 | ||
97 | if (test_and_clear_bit(PG_dcache_dirty, &page->flags)) | |
98 | __flush_dcache_page(page_mapping(page), page); | |
99 | ||
f8f98a93 RK |
100 | spin_lock(&minicache_lock); |
101 | ||
ad1ae2fe | 102 | set_pte_ext(TOP_PTE(COPYPAGE_MINICACHE), pfn_pte(__pa(kfrom) >> PAGE_SHIFT, minicache_pgprot), 0); |
f8f98a93 RK |
103 | flush_tlb_kernel_page(COPYPAGE_MINICACHE); |
104 | ||
105 | mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto); | |
106 | ||
107 | spin_unlock(&minicache_lock); | |
108 | } | |
109 | ||
110 | /* | |
111 | * XScale optimised clear_user_page | |
112 | */ | |
113 | void __attribute__((naked)) | |
114 | xscale_mc_clear_user_page(void *kaddr, unsigned long vaddr) | |
115 | { | |
116 | asm volatile( | |
117 | "mov r1, %0 \n\ | |
118 | mov r2, #0 \n\ | |
119 | mov r3, #0 \n\ | |
120 | 1: mov ip, r0 \n\ | |
121 | strd r2, [r0], #8 \n\ | |
122 | strd r2, [r0], #8 \n\ | |
123 | strd r2, [r0], #8 \n\ | |
124 | strd r2, [r0], #8 \n\ | |
125 | mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ | |
126 | subs r1, r1, #1 \n\ | |
127 | mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ | |
128 | bne 1b \n\ | |
129 | mov pc, lr" | |
130 | : | |
131 | : "I" (PAGE_SIZE / 32)); | |
132 | } | |
133 | ||
134 | struct cpu_user_fns xscale_mc_user_fns __initdata = { | |
135 | .cpu_clear_user_page = xscale_mc_clear_user_page, | |
136 | .cpu_copy_user_page = xscale_mc_copy_user_page, | |
137 | }; |