diff options
Diffstat (limited to 'arch/arm/mm/minicache.c')
-rw-r--r-- | arch/arm/mm/minicache.c | 73 |
1 files changed, 0 insertions, 73 deletions
diff --git a/arch/arm/mm/minicache.c b/arch/arm/mm/minicache.c index dedf2ab01b2a..e69de29bb2d1 100644 --- a/arch/arm/mm/minicache.c +++ b/arch/arm/mm/minicache.c | |||
@@ -1,73 +0,0 @@ | |||
1 | /* | ||
2 | * linux/arch/arm/mm/minicache.c | ||
3 | * | ||
4 | * Copyright (C) 2001 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 minicache_address (0xffff8000) | ||
28 | #define minicache_pgprot __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | \ | ||
29 | L_PTE_CACHEABLE) | ||
30 | |||
31 | static pte_t *minicache_pte; | ||
32 | |||
33 | /* | ||
34 | * Note that this is intended to be called only from the copy_user_page | ||
35 | * asm code; anything else will require special locking to prevent the | ||
36 | * mini-cache space being re-used. (Note: probably preempt unsafe). | ||
37 | * | ||
38 | * We rely on the fact that the minicache is 2K, and we'll be pushing | ||
39 | * 4K of data through it, so we don't actually have to specifically | ||
40 | * flush the minicache when we change the mapping. | ||
41 | * | ||
42 | * Note also: assert(PAGE_OFFSET <= virt < high_memory). | ||
43 | * Unsafe: preempt, kmap. | ||
44 | */ | ||
45 | unsigned long map_page_minicache(unsigned long virt) | ||
46 | { | ||
47 | set_pte(minicache_pte, pfn_pte(__pa(virt) >> PAGE_SHIFT, minicache_pgprot)); | ||
48 | flush_tlb_kernel_page(minicache_address); | ||
49 | |||
50 | return minicache_address; | ||
51 | } | ||
52 | |||
53 | static int __init minicache_init(void) | ||
54 | { | ||
55 | pgd_t *pgd; | ||
56 | pmd_t *pmd; | ||
57 | |||
58 | spin_lock(&init_mm.page_table_lock); | ||
59 | |||
60 | pgd = pgd_offset_k(minicache_address); | ||
61 | pmd = pmd_alloc(&init_mm, pgd, minicache_address); | ||
62 | if (!pmd) | ||
63 | BUG(); | ||
64 | minicache_pte = pte_alloc_kernel(&init_mm, pmd, minicache_address); | ||
65 | if (!minicache_pte) | ||
66 | BUG(); | ||
67 | |||
68 | spin_unlock(&init_mm.page_table_lock); | ||
69 | |||
70 | return 0; | ||
71 | } | ||
72 | |||
73 | core_initcall(minicache_init); | ||