mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race
[linux/fpc-iii.git] / arch / arm / kernel / efi.c
blob9f43ba012d1077ef553617bff01cf002fba70613
1 /*
2 * Copyright (C) 2015 Linaro Ltd <ard.biesheuvel@linaro.org>
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 */
9 #include <linux/efi.h>
10 #include <asm/efi.h>
11 #include <asm/mach/map.h>
12 #include <asm/mmu_context.h>
14 static int __init set_permissions(pte_t *ptep, pgtable_t token,
15 unsigned long addr, void *data)
17 efi_memory_desc_t *md = data;
18 pte_t pte = *ptep;
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;
28 int __init efi_set_mapping_permissions(struct mm_struct *mm,
29 efi_memory_desc_t *md)
31 unsigned long base, size;
33 base = md->virt_addr;
34 size = md->num_pages << EFI_PAGE_SHIFT;
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.
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);
46 return 0;
49 int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
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,
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.
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;
71 create_mapping_late(mm, &desc, true);
74 * If stricter permissions were specified, apply them now.
76 if (md->attribute & (EFI_MEMORY_RO | EFI_MEMORY_XP))
77 return efi_set_mapping_permissions(mm, md);
78 return 0;