Commit | Line | Data |
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65559100 MF |
1 | /* |
2 | * High memory support for Xtensa architecture | |
3 | * | |
4 | * This file is subject to the terms and conditions of the GNU General | |
5 | * Public License. See the file "COPYING" in the main directory of | |
6 | * this archive for more details. | |
7 | * | |
8 | * Copyright (C) 2014 Cadence Design Systems Inc. | |
9 | */ | |
10 | ||
11 | #include <linux/export.h> | |
12 | #include <linux/highmem.h> | |
13 | #include <asm/tlbflush.h> | |
14 | ||
15 | static pte_t *kmap_pte; | |
16 | ||
8504b503 MF |
17 | #if DCACHE_WAY_SIZE > PAGE_SIZE |
18 | unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS]; | |
19 | wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS]; | |
20 | ||
21 | static void __init kmap_waitqueues_init(void) | |
22 | { | |
23 | unsigned int i; | |
24 | ||
25 | for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i) | |
26 | init_waitqueue_head(pkmap_map_wait_arr + i); | |
27 | } | |
28 | #else | |
29 | static inline void kmap_waitqueues_init(void) | |
30 | { | |
31 | } | |
32 | #endif | |
33 | ||
32544d9c MF |
34 | static inline enum fixed_addresses kmap_idx(int type, unsigned long color) |
35 | { | |
36 | return (type + KM_TYPE_NR * smp_processor_id()) * DCACHE_N_COLORS + | |
37 | color; | |
38 | } | |
39 | ||
65559100 MF |
40 | void *kmap_atomic(struct page *page) |
41 | { | |
42 | enum fixed_addresses idx; | |
43 | unsigned long vaddr; | |
65559100 | 44 | |
2cb7c9cb | 45 | preempt_disable(); |
65559100 MF |
46 | pagefault_disable(); |
47 | if (!PageHighMem(page)) | |
48 | return page_address(page); | |
49 | ||
32544d9c MF |
50 | idx = kmap_idx(kmap_atomic_idx_push(), |
51 | DCACHE_ALIAS(page_to_phys(page))); | |
65559100 MF |
52 | vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); |
53 | #ifdef CONFIG_DEBUG_HIGHMEM | |
22def768 | 54 | BUG_ON(!pte_none(*(kmap_pte + idx))); |
65559100 | 55 | #endif |
22def768 | 56 | set_pte(kmap_pte + idx, mk_pte(page, PAGE_KERNEL_EXEC)); |
65559100 MF |
57 | |
58 | return (void *)vaddr; | |
59 | } | |
60 | EXPORT_SYMBOL(kmap_atomic); | |
61 | ||
62 | void __kunmap_atomic(void *kvaddr) | |
63 | { | |
65559100 MF |
64 | if (kvaddr >= (void *)FIXADDR_START && |
65 | kvaddr < (void *)FIXADDR_TOP) { | |
32544d9c MF |
66 | int idx = kmap_idx(kmap_atomic_idx(), |
67 | DCACHE_ALIAS((unsigned long)kvaddr)); | |
65559100 MF |
68 | |
69 | /* | |
70 | * Force other mappings to Oops if they'll try to access this | |
71 | * pte without first remap it. Keeping stale mappings around | |
72 | * is a bad idea also, in case the page changes cacheability | |
73 | * attributes or becomes a protected page in a hypervisor. | |
74 | */ | |
22def768 | 75 | pte_clear(&init_mm, kvaddr, kmap_pte + idx); |
65559100 MF |
76 | local_flush_tlb_kernel_range((unsigned long)kvaddr, |
77 | (unsigned long)kvaddr + PAGE_SIZE); | |
78 | ||
79 | kmap_atomic_idx_pop(); | |
80 | } | |
81 | ||
82 | pagefault_enable(); | |
2cb7c9cb | 83 | preempt_enable(); |
65559100 MF |
84 | } |
85 | EXPORT_SYMBOL(__kunmap_atomic); | |
86 | ||
87 | void __init kmap_init(void) | |
88 | { | |
89 | unsigned long kmap_vstart; | |
90 | ||
91 | /* cache the first kmap pte */ | |
92 | kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); | |
93 | kmap_pte = kmap_get_fixmap_pte(kmap_vstart); | |
8504b503 | 94 | kmap_waitqueues_init(); |
65559100 | 95 | } |