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Diffstat (limited to 'arch/arm/kernel/efi.c')
-rw-r--r--arch/arm/kernel/efi.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/arm/kernel/efi.c b/arch/arm/kernel/efi.c
index ff8a9d8ac..9f43ba012 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;
}