diff options
Diffstat (limited to 'arch/arm/mm/copypage-xscale.c')
-rw-r--r-- | arch/arm/mm/copypage-xscale.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/arch/arm/mm/copypage-xscale.c b/arch/arm/mm/copypage-xscale.c new file mode 100644 index 000000000000..42a6ee255ce0 --- /dev/null +++ b/arch/arm/mm/copypage-xscale.c | |||
@@ -0,0 +1,131 @@ | |||
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> | ||
22 | |||
23 | /* | ||
24 | * 0xffff8000 to 0xffffffff is reserved for any ARM architecture | ||
25 | * specific hacks for copying pages efficiently. | ||
26 | */ | ||
27 | #define COPYPAGE_MINICACHE 0xffff8000 | ||
28 | |||
29 | #define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \ | ||
30 | L_PTE_CACHEABLE) | ||
31 | |||
32 | #define TOP_PTE(x) pte_offset_kernel(top_pmd, x) | ||
33 | |||
34 | static DEFINE_SPINLOCK(minicache_lock); | ||
35 | |||
36 | /* | ||
37 | * XScale mini-dcache optimised copy_user_page | ||
38 | * | ||
39 | * We flush the destination cache lines just before we write the data into the | ||
40 | * corresponding address. Since the Dcache is read-allocate, this removes the | ||
41 | * Dcache aliasing issue. The writes will be forwarded to the write buffer, | ||
42 | * and merged as appropriate. | ||
43 | */ | ||
44 | static void __attribute__((naked)) | ||
45 | mc_copy_user_page(void *from, void *to) | ||
46 | { | ||
47 | /* | ||
48 | * Strangely enough, best performance is achieved | ||
49 | * when prefetching destination as well. (NP) | ||
50 | */ | ||
51 | asm volatile( | ||
52 | "stmfd sp!, {r4, r5, lr} \n\ | ||
53 | mov lr, %2 \n\ | ||
54 | pld [r0, #0] \n\ | ||
55 | pld [r0, #32] \n\ | ||
56 | pld [r1, #0] \n\ | ||
57 | pld [r1, #32] \n\ | ||
58 | 1: pld [r0, #64] \n\ | ||
59 | pld [r0, #96] \n\ | ||
60 | pld [r1, #64] \n\ | ||
61 | pld [r1, #96] \n\ | ||
62 | 2: ldrd r2, [r0], #8 \n\ | ||
63 | ldrd r4, [r0], #8 \n\ | ||
64 | mov ip, r1 \n\ | ||
65 | strd r2, [r1], #8 \n\ | ||
66 | ldrd r2, [r0], #8 \n\ | ||
67 | strd r4, [r1], #8 \n\ | ||
68 | ldrd r4, [r0], #8 \n\ | ||
69 | strd r2, [r1], #8 \n\ | ||
70 | strd r4, [r1], #8 \n\ | ||
71 | mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ | ||
72 | ldrd r2, [r0], #8 \n\ | ||
73 | mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ | ||
74 | ldrd r4, [r0], #8 \n\ | ||
75 | mov ip, r1 \n\ | ||
76 | strd r2, [r1], #8 \n\ | ||
77 | ldrd r2, [r0], #8 \n\ | ||
78 | strd r4, [r1], #8 \n\ | ||
79 | ldrd r4, [r0], #8 \n\ | ||
80 | strd r2, [r1], #8 \n\ | ||
81 | strd r4, [r1], #8 \n\ | ||
82 | mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ | ||
83 | subs lr, lr, #1 \n\ | ||
84 | mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ | ||
85 | bgt 1b \n\ | ||
86 | beq 2b \n\ | ||
87 | ldmfd sp!, {r4, r5, pc} " | ||
88 | : | ||
89 | : "r" (from), "r" (to), "I" (PAGE_SIZE / 64 - 1)); | ||
90 | } | ||
91 | |||
92 | void xscale_mc_copy_user_page(void *kto, const void *kfrom, unsigned long vaddr) | ||
93 | { | ||
94 | spin_lock(&minicache_lock); | ||
95 | |||
96 | set_pte(TOP_PTE(COPYPAGE_MINICACHE), pfn_pte(__pa(kfrom) >> PAGE_SHIFT, minicache_pgprot)); | ||
97 | flush_tlb_kernel_page(COPYPAGE_MINICACHE); | ||
98 | |||
99 | mc_copy_user_page((void *)COPYPAGE_MINICACHE, kto); | ||
100 | |||
101 | spin_unlock(&minicache_lock); | ||
102 | } | ||
103 | |||
104 | /* | ||
105 | * XScale optimised clear_user_page | ||
106 | */ | ||
107 | void __attribute__((naked)) | ||
108 | xscale_mc_clear_user_page(void *kaddr, unsigned long vaddr) | ||
109 | { | ||
110 | asm volatile( | ||
111 | "mov r1, %0 \n\ | ||
112 | mov r2, #0 \n\ | ||
113 | mov r3, #0 \n\ | ||
114 | 1: mov ip, r0 \n\ | ||
115 | strd r2, [r0], #8 \n\ | ||
116 | strd r2, [r0], #8 \n\ | ||
117 | strd r2, [r0], #8 \n\ | ||
118 | strd r2, [r0], #8 \n\ | ||
119 | mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\ | ||
120 | subs r1, r1, #1 \n\ | ||
121 | mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\ | ||
122 | bne 1b \n\ | ||
123 | mov pc, lr" | ||
124 | : | ||
125 | : "I" (PAGE_SIZE / 32)); | ||
126 | } | ||
127 | |||
128 | struct cpu_user_fns xscale_mc_user_fns __initdata = { | ||
129 | .cpu_clear_user_page = xscale_mc_clear_user_page, | ||
130 | .cpu_copy_user_page = xscale_mc_copy_user_page, | ||
131 | }; | ||