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fd940934 KP |
1 | /* |
2 | * Copyright © 2008 Ingo Molnar | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, but | |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License along | |
15 | * with this program; if not, write to the Free Software Foundation, Inc., | |
16 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. | |
17 | */ | |
18 | ||
19 | #include <asm/iomap.h> | |
ef5fa0ab | 20 | #include <asm/pat.h> |
fd940934 KP |
21 | #include <linux/module.h> |
22 | ||
4ab0d47d | 23 | #ifdef CONFIG_X86_PAE |
17581ad8 | 24 | static int |
4ab0d47d VP |
25 | is_io_mapping_possible(resource_size_t base, unsigned long size) |
26 | { | |
27 | return 1; | |
28 | } | |
29 | #else | |
17581ad8 | 30 | static int |
4ab0d47d VP |
31 | is_io_mapping_possible(resource_size_t base, unsigned long size) |
32 | { | |
33 | /* There is no way to map greater than 1 << 32 address without PAE */ | |
34 | if (base + size > 0x100000000ULL) | |
35 | return 0; | |
36 | ||
37 | return 1; | |
38 | } | |
39 | #endif | |
40 | ||
17581ad8 VP |
41 | int |
42 | reserve_io_memtype_wc(u64 base, unsigned long size, pgprot_t *prot) | |
43 | { | |
44 | unsigned long ret_flag; | |
45 | ||
46 | if (!is_io_mapping_possible(base, size)) | |
47 | goto out_err; | |
48 | ||
49 | if (!pat_enabled) { | |
50 | *prot = pgprot_noncached(PAGE_KERNEL); | |
51 | return 0; | |
52 | } | |
53 | ||
54 | if (reserve_memtype(base, base + size, _PAGE_CACHE_WC, &ret_flag)) | |
55 | goto out_err; | |
56 | ||
57 | if (ret_flag == _PAGE_CACHE_WB) | |
58 | goto out_free; | |
59 | ||
60 | if (kernel_map_sync_memtype(base, size, ret_flag)) | |
61 | goto out_free; | |
62 | ||
63 | *prot = __pgprot(__PAGE_KERNEL | ret_flag); | |
64 | return 0; | |
65 | ||
66 | out_free: | |
67 | free_memtype(base, base + size); | |
68 | out_err: | |
69 | return -EINVAL; | |
70 | } | |
71 | ||
72 | void | |
73 | free_io_memtype(u64 base, unsigned long size) | |
74 | { | |
75 | if (pat_enabled) | |
76 | free_memtype(base, base + size); | |
77 | } | |
78 | ||
fd940934 KP |
79 | /* Map 'pfn' using fixed map 'type' and protections 'prot' |
80 | */ | |
81 | void * | |
82 | iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot) | |
83 | { | |
84 | enum fixed_addresses idx; | |
85 | unsigned long vaddr; | |
86 | ||
87 | pagefault_disable(); | |
88 | ||
ef5fa0ab EA |
89 | /* |
90 | * For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS. | |
91 | * PAGE_KERNEL_WC maps to PWT, which translates to uncached if the | |
92 | * MTRR is UC or WC. UC_MINUS gets the real intention, of the | |
93 | * user, which is "WC if the MTRR is WC, UC if you can't do that." | |
94 | */ | |
95 | if (!pat_enabled && pgprot_val(prot) == pgprot_val(PAGE_KERNEL_WC)) | |
96 | prot = PAGE_KERNEL_UC_MINUS; | |
97 | ||
fd940934 KP |
98 | idx = type + KM_TYPE_NR*smp_processor_id(); |
99 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); | |
100 | set_pte(kmap_pte-idx, pfn_pte(pfn, prot)); | |
101 | arch_flush_lazy_mmu_mode(); | |
102 | ||
103 | return (void*) vaddr; | |
104 | } | |
105 | EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn); | |
106 | ||
107 | void | |
108 | iounmap_atomic(void *kvaddr, enum km_type type) | |
109 | { | |
110 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; | |
111 | enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); | |
112 | ||
113 | /* | |
114 | * Force other mappings to Oops if they'll try to access this pte | |
115 | * without first remap it. Keeping stale mappings around is a bad idea | |
116 | * also, in case the page changes cacheability attributes or becomes | |
117 | * a protected page in a hypervisor. | |
118 | */ | |
119 | if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx)) | |
120 | kpte_clear_flush(kmap_pte-idx, vaddr); | |
121 | ||
122 | arch_flush_lazy_mmu_mode(); | |
123 | pagefault_enable(); | |
124 | } | |
125 | EXPORT_SYMBOL_GPL(iounmap_atomic); |