diff options
Diffstat (limited to 'arch/arm/kernel/efi.c')
| -rw-r--r-- | arch/arm/kernel/efi.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/arm/kernel/efi.c b/arch/arm/kernel/efi.c index ff8a9d8acfac..9f43ba012d10 100644 --- a/arch/arm/kernel/efi.c +++ b/arch/arm/kernel/efi.c @@ -11,6 +11,41 @@ #include <asm/mach/map.h> #include <asm/mmu_context.h> +static int __init set_permissions(pte_t *ptep, pgtable_t token, + unsigned long addr, void *data) +{ + efi_memory_desc_t *md = data; + pte_t pte = *ptep; + + if (md->attribute & EFI_MEMORY_RO) + pte = set_pte_bit(pte, __pgprot(L_PTE_RDONLY)); + if (md->attribute & EFI_MEMORY_XP) + pte = set_pte_bit(pte, __pgprot(L_PTE_XN)); + set_pte_ext(ptep, pte, PTE_EXT_NG); + return 0; +} + +int __init efi_set_mapping_permissions(struct mm_struct *mm, + efi_memory_desc_t *md) +{ + unsigned long base, size; + + base = md->virt_addr; + size = md->num_pages << EFI_PAGE_SHIFT; + + /* + * We can only use apply_to_page_range() if we can guarantee that the + * entire region was mapped using pages. This should be the case if the + * region does not cover any naturally aligned SECTION_SIZE sized + * blocks. + */ + if (round_down(base + size, SECTION_SIZE) < + round_up(base, SECTION_SIZE) + SECTION_SIZE) + return apply_to_page_range(mm, base, size, set_permissions, md); + + return 0; +} + int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md) { struct map_desc desc = { @@ -34,5 +69,11 @@ int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md) desc.type = MT_DEVICE; create_mapping_late(mm, &desc, true); + + /* + * If stricter permissions were specified, apply them now. + */ + if (md->attribute & (EFI_MEMORY_RO | EFI_MEMORY_XP)) + return efi_set_mapping_permissions(mm, md); return 0; } |