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da58fb65 AB |
1 | /* |
2 | * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org> | |
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 version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | ||
9 | #include <linux/efi.h> | |
10 | #include <asm/efi.h> | |
11 | #include <asm/mach/map.h> | |
12 | #include <asm/mmu_context.h> | |
13 | ||
9fc68b71 AB |
14 | static int __init set_permissions(pte_t *ptep, pgtable_t token, |
15 | unsigned long addr, void *data) | |
16 | { | |
17 | efi_memory_desc_t *md = data; | |
18 | pte_t pte = *ptep; | |
19 | ||
20 | if (md->attribute & EFI_MEMORY_RO) | |
21 | pte = set_pte_bit(pte, __pgprot(L_PTE_RDONLY)); | |
22 | if (md->attribute & EFI_MEMORY_XP) | |
23 | pte = set_pte_bit(pte, __pgprot(L_PTE_XN)); | |
24 | set_pte_ext(ptep, pte, PTE_EXT_NG); | |
25 | return 0; | |
26 | } | |
27 | ||
28 | int __init efi_set_mapping_permissions(struct mm_struct *mm, | |
29 | efi_memory_desc_t *md) | |
30 | { | |
31 | unsigned long base, size; | |
32 | ||
33 | base = md->virt_addr; | |
34 | size = md->num_pages << EFI_PAGE_SHIFT; | |
35 | ||
36 | /* | |
37 | * We can only use apply_to_page_range() if we can guarantee that the | |
38 | * entire region was mapped using pages. This should be the case if the | |
39 | * region does not cover any naturally aligned SECTION_SIZE sized | |
40 | * blocks. | |
41 | */ | |
42 | if (round_down(base + size, SECTION_SIZE) < | |
43 | round_up(base, SECTION_SIZE) + SECTION_SIZE) | |
44 | return apply_to_page_range(mm, base, size, set_permissions, md); | |
45 | ||
46 | return 0; | |
47 | } | |
48 | ||
da58fb65 AB |
49 | int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md) |
50 | { | |
51 | struct map_desc desc = { | |
52 | .virtual = md->virt_addr, | |
53 | .pfn = __phys_to_pfn(md->phys_addr), | |
54 | .length = md->num_pages * EFI_PAGE_SIZE, | |
55 | }; | |
56 | ||
57 | /* | |
58 | * Order is important here: memory regions may have all of the | |
59 | * bits below set (and usually do), so we check them in order of | |
60 | * preference. | |
61 | */ | |
62 | if (md->attribute & EFI_MEMORY_WB) | |
63 | desc.type = MT_MEMORY_RWX; | |
64 | else if (md->attribute & EFI_MEMORY_WT) | |
65 | desc.type = MT_MEMORY_RWX_NONCACHED; | |
66 | else if (md->attribute & EFI_MEMORY_WC) | |
67 | desc.type = MT_DEVICE_WC; | |
68 | else | |
69 | desc.type = MT_DEVICE; | |
70 | ||
71 | create_mapping_late(mm, &desc, true); | |
9fc68b71 AB |
72 | |
73 | /* | |
74 | * If stricter permissions were specified, apply them now. | |
75 | */ | |
76 | if (md->attribute & (EFI_MEMORY_RO | EFI_MEMORY_XP)) | |
77 | return efi_set_mapping_permissions(mm, md); | |
da58fb65 AB |
78 | return 0; |
79 | } |