@@ -114,6 +114,8 @@ static inline unsigned long efi_get_kimg_min_align(void)
#define EFI_ALLOC_ALIGN SZ_64K
#define EFI_ALLOC_LIMIT ((1UL << 48) - 1)
+#define EFI_USE_FLAT_VA_MAPPING (VA_BITS_MIN >= 48)
+
/*
* On ARM systems, virtually remapped UEFI runtime services are set up in two
* distinct stages:
@@ -44,8 +44,12 @@
#define EFI_RT_VIRTUAL_OFFSET 0
#endif
+#ifndef EFI_USE_FLAT_VA_MAPPING
+#define EFI_USE_FLAT_VA_MAPPING (EFI_RT_VIRTUAL_OFFSET != 0)
+#endif
+
static u64 virtmap_base = EFI_RT_VIRTUAL_BASE;
-static bool flat_va_mapping = (EFI_RT_VIRTUAL_OFFSET != 0);
+static bool flat_va_mapping = EFI_USE_FLAT_VA_MAPPING;
struct screen_info * __weak alloc_screen_info(void)
{
With some systems, we cannot omit the boot time call to SetVirtualAddressMap() even if the kernel VA space is sufficiently large, because some buggy EFI implementations exist that misbehave if SetVirtualAddressMap() is never called. However, this does not mean we must reshuffle the EFI memory map: we can simply invoke SetVirtualAddressMap() with a memory map that places each EFI runtime region at the same virtual address that it takes up in the physical address map. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/arm64/include/asm/efi.h | 2 ++ drivers/firmware/efi/libstub/efi-stub.c | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-)