diff options
Diffstat (limited to 'arch/arm64/kernel/efi.c')
| -rw-r--r-- | arch/arm64/kernel/efi.c | 57 |
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, |