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d73cd428 NP |
1 | /* |
2 | * arch/arm/mm/highmem.c -- ARM highmem support | |
3 | * | |
4 | * Author: Nicolas Pitre | |
5 | * Created: september 8, 2008 | |
6 | * Copyright: Marvell Semiconductors Inc. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/highmem.h> | |
15 | #include <linux/interrupt.h> | |
16 | #include <asm/fixmap.h> | |
17 | #include <asm/cacheflush.h> | |
18 | #include <asm/tlbflush.h> | |
19 | #include "mm.h" | |
20 | ||
21 | void *kmap(struct page *page) | |
22 | { | |
23 | might_sleep(); | |
24 | if (!PageHighMem(page)) | |
25 | return page_address(page); | |
26 | return kmap_high(page); | |
27 | } | |
28 | EXPORT_SYMBOL(kmap); | |
29 | ||
30 | void kunmap(struct page *page) | |
31 | { | |
32 | BUG_ON(in_interrupt()); | |
33 | if (!PageHighMem(page)) | |
34 | return; | |
35 | kunmap_high(page); | |
36 | } | |
37 | EXPORT_SYMBOL(kunmap); | |
38 | ||
39 | void *kmap_atomic(struct page *page, enum km_type type) | |
40 | { | |
41 | unsigned int idx; | |
42 | unsigned long vaddr; | |
7929eb9c | 43 | void *kmap; |
d73cd428 NP |
44 | |
45 | pagefault_disable(); | |
46 | if (!PageHighMem(page)) | |
47 | return page_address(page); | |
48 | ||
6a5e293f RK |
49 | debug_kmap_atomic(type); |
50 | ||
7929eb9c NP |
51 | kmap = kmap_high_get(page); |
52 | if (kmap) | |
53 | return kmap; | |
54 | ||
d73cd428 NP |
55 | idx = type + KM_TYPE_NR * smp_processor_id(); |
56 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); | |
57 | #ifdef CONFIG_DEBUG_HIGHMEM | |
58 | /* | |
59 | * With debugging enabled, kunmap_atomic forces that entry to 0. | |
60 | * Make sure it was indeed properly unmapped. | |
61 | */ | |
62 | BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); | |
63 | #endif | |
64 | set_pte_ext(TOP_PTE(vaddr), mk_pte(page, kmap_prot), 0); | |
65 | /* | |
66 | * When debugging is off, kunmap_atomic leaves the previous mapping | |
67 | * in place, so this TLB flush ensures the TLB is updated with the | |
68 | * new mapping. | |
69 | */ | |
70 | local_flush_tlb_kernel_page(vaddr); | |
71 | ||
72 | return (void *)vaddr; | |
73 | } | |
74 | EXPORT_SYMBOL(kmap_atomic); | |
75 | ||
76 | void kunmap_atomic(void *kvaddr, enum km_type type) | |
77 | { | |
78 | unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; | |
79 | unsigned int idx = type + KM_TYPE_NR * smp_processor_id(); | |
80 | ||
81 | if (kvaddr >= (void *)FIXADDR_START) { | |
7e5a69e8 NP |
82 | if (cache_is_vivt()) |
83 | __cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE); | |
d73cd428 NP |
84 | #ifdef CONFIG_DEBUG_HIGHMEM |
85 | BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx)); | |
86 | set_pte_ext(TOP_PTE(vaddr), __pte(0), 0); | |
87 | local_flush_tlb_kernel_page(vaddr); | |
88 | #else | |
89 | (void) idx; /* to kill a warning */ | |
90 | #endif | |
7929eb9c NP |
91 | } else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) { |
92 | /* this address was obtained through kmap_high_get() */ | |
93 | kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)])); | |
d73cd428 NP |
94 | } |
95 | pagefault_enable(); | |
96 | } | |
97 | EXPORT_SYMBOL(kunmap_atomic); | |
98 | ||
99 | void *kmap_atomic_pfn(unsigned long pfn, enum km_type type) | |
100 | { | |
101 | unsigned int idx; | |
102 | unsigned long vaddr; | |
103 | ||
104 | pagefault_disable(); | |
105 | ||
106 | idx = type + KM_TYPE_NR * smp_processor_id(); | |
107 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); | |
108 | #ifdef CONFIG_DEBUG_HIGHMEM | |
109 | BUG_ON(!pte_none(*(TOP_PTE(vaddr)))); | |
110 | #endif | |
111 | set_pte_ext(TOP_PTE(vaddr), pfn_pte(pfn, kmap_prot), 0); | |
112 | local_flush_tlb_kernel_page(vaddr); | |
113 | ||
114 | return (void *)vaddr; | |
115 | } | |
116 | ||
117 | struct page *kmap_atomic_to_page(const void *ptr) | |
118 | { | |
119 | unsigned long vaddr = (unsigned long)ptr; | |
120 | pte_t *pte; | |
121 | ||
122 | if (vaddr < FIXADDR_START) | |
123 | return virt_to_page(ptr); | |
124 | ||
125 | pte = TOP_PTE(vaddr); | |
126 | return pte_page(*pte); | |
127 | } | |
7e5a69e8 NP |
128 | |
129 | #ifdef CONFIG_CPU_CACHE_VIPT | |
130 | ||
131 | #include <linux/percpu.h> | |
132 | ||
133 | /* | |
134 | * The VIVT cache of a highmem page is always flushed before the page | |
135 | * is unmapped. Hence unmapped highmem pages need no cache maintenance | |
136 | * in that case. | |
137 | * | |
138 | * However unmapped pages may still be cached with a VIPT cache, and | |
139 | * it is not possible to perform cache maintenance on them using physical | |
140 | * addresses unfortunately. So we have no choice but to set up a temporary | |
141 | * virtual mapping for that purpose. | |
142 | * | |
143 | * Yet this VIPT cache maintenance may be triggered from DMA support | |
144 | * functions which are possibly called from interrupt context. As we don't | |
145 | * want to keep interrupt disabled all the time when such maintenance is | |
146 | * taking place, we therefore allow for some reentrancy by preserving and | |
147 | * restoring the previous fixmap entry before the interrupted context is | |
148 | * resumed. If the reentrancy depth is 0 then there is no need to restore | |
149 | * the previous fixmap, and leaving the current one in place allow it to | |
150 | * be reused the next time without a TLB flush (common with DMA). | |
151 | */ | |
152 | ||
153 | static DEFINE_PER_CPU(int, kmap_high_l1_vipt_depth); | |
154 | ||
155 | void *kmap_high_l1_vipt(struct page *page, pte_t *saved_pte) | |
156 | { | |
157 | unsigned int idx, cpu = smp_processor_id(); | |
158 | int *depth = &per_cpu(kmap_high_l1_vipt_depth, cpu); | |
159 | unsigned long vaddr, flags; | |
160 | pte_t pte, *ptep; | |
161 | ||
162 | idx = KM_L1_CACHE + KM_TYPE_NR * cpu; | |
163 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); | |
164 | ptep = TOP_PTE(vaddr); | |
165 | pte = mk_pte(page, kmap_prot); | |
166 | ||
167 | if (!in_interrupt()) | |
168 | preempt_disable(); | |
169 | ||
170 | raw_local_irq_save(flags); | |
171 | (*depth)++; | |
172 | if (pte_val(*ptep) == pte_val(pte)) { | |
173 | *saved_pte = pte; | |
174 | } else { | |
175 | *saved_pte = *ptep; | |
176 | set_pte_ext(ptep, pte, 0); | |
177 | local_flush_tlb_kernel_page(vaddr); | |
178 | } | |
179 | raw_local_irq_restore(flags); | |
180 | ||
181 | return (void *)vaddr; | |
182 | } | |
183 | ||
184 | void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte) | |
185 | { | |
186 | unsigned int idx, cpu = smp_processor_id(); | |
187 | int *depth = &per_cpu(kmap_high_l1_vipt_depth, cpu); | |
188 | unsigned long vaddr, flags; | |
189 | pte_t pte, *ptep; | |
190 | ||
191 | idx = KM_L1_CACHE + KM_TYPE_NR * cpu; | |
192 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); | |
193 | ptep = TOP_PTE(vaddr); | |
194 | pte = mk_pte(page, kmap_prot); | |
195 | ||
196 | BUG_ON(pte_val(*ptep) != pte_val(pte)); | |
197 | BUG_ON(*depth <= 0); | |
198 | ||
199 | raw_local_irq_save(flags); | |
200 | (*depth)--; | |
201 | if (*depth != 0 && pte_val(pte) != pte_val(saved_pte)) { | |
202 | set_pte_ext(ptep, saved_pte, 0); | |
203 | local_flush_tlb_kernel_page(vaddr); | |
204 | } | |
205 | raw_local_irq_restore(flags); | |
206 | ||
207 | if (!in_interrupt()) | |
208 | preempt_enable(); | |
209 | } | |
210 | ||
211 | #endif /* CONFIG_CPU_CACHE_VIPT */ |