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Diffstat (limited to 'arch/arm64/kernel/efi.c')
-rw-r--r--arch/arm64/kernel/efi.c57
1 files changed, 43 insertions, 14 deletions
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index b6abc852f2a1..78f52488f9ff 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -17,22 +17,51 @@
#include <asm/efi.h>
-int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
+/*
+ * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
+ * executable, everything else can be mapped with the XN bits
+ * set. Also take the new (optional) RO/XP bits into account.
+ */
+static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
{
- pteval_t prot_val;
+ u64 attr = md->attribute;
+ u32 type = md->type;
- /*
- * Only regions of type EFI_RUNTIME_SERVICES_CODE need to be
- * executable, everything else can be mapped with the XN bits
- * set.
- */
- if ((md->attribute & EFI_MEMORY_WB) == 0)
- prot_val = PROT_DEVICE_nGnRE;
- else if (md->type == EFI_RUNTIME_SERVICES_CODE ||
- !PAGE_ALIGNED(md->phys_addr))
- prot_val = pgprot_val(PAGE_KERNEL_EXEC);
- else
- prot_val = pgprot_val(PAGE_KERNEL);
+ if (type == EFI_MEMORY_MAPPED_IO)
+ return PROT_DEVICE_nGnRE;
+
+ if (WARN_ONCE(!PAGE_ALIGNED(md->phys_addr),
+ "UEFI Runtime regions are not aligned to 64 KB -- buggy firmware?"))
+ /*
+ * If the region is not aligned to the page size of the OS, we
+ * can not use strict permissions, since that would also affect
+ * the mapping attributes of the adjacent regions.
+ */
+ return pgprot_val(PAGE_KERNEL_EXEC);
+
+ /* R-- */
+ if ((attr & (EFI_MEMORY_XP | EFI_MEMORY_RO)) ==
+ (EFI_MEMORY_XP | EFI_MEMORY_RO))
+ return pgprot_val(PAGE_KERNEL_RO);
+
+ /* R-X */
+ if (attr & EFI_MEMORY_RO)
+ return pgprot_val(PAGE_KERNEL_ROX);
+
+ /* RW- */
+ if (attr & EFI_MEMORY_XP || type != EFI_RUNTIME_SERVICES_CODE)
+ return pgprot_val(PAGE_KERNEL);
+
+ /* RWX */
+ return pgprot_val(PAGE_KERNEL_EXEC);
+}
+
+/* we will fill this structure from the stub, so don't put it in .bss */
+struct screen_info screen_info __section(.data);
+
+int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
+{
+ pteval_t prot_val = create_mapping_protection(md);
create_pgd_mapping(mm, md->phys_addr, md->virt_addr,
md->num_pages << EFI_PAGE_SHIFT,