efi_loader: set IMAGE_DLLCHARACTERISTICS_NX_COMPAT
The IMAGE_DLLCHARACTERISTICS_NX_COMPAT flag marks an EFI binary where
the following conditions are met [1]:
* Executable and writable sections are separated.
* The application does not run self-modifying code.
* The application uses the EFI_MEMORY_ATTRIBUTE_PROTOCOL when loading
executable code.
* The application does not assume that all memory ranges are usable.
* The stack is not expected to be executable.
The only EFI binaries U-Boot provides that do not fulfill these
requirements are the EFI app and the EFI payload.
Once we have implemented separation of writable and executable memory in
U-Boot we can use the IMAGE_DLLCHARACTERISTICS_NX_COMPAT flag to decide
if we will load an EFI binary.
[1] New UEFI CA memory mitigation requirements for signing
https://techcommunity.microsoft.com/t5/hardware-dev-center/new-uefi-ca-memory-mitigation-requirements-for-signing/ba-p/3608714
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/include/asm-generic/pe.h b/include/asm-generic/pe.h
index b9d674b..cd5b6ad 100644
--- a/include/asm-generic/pe.h
+++ b/include/asm-generic/pe.h
@@ -51,6 +51,9 @@
#define IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER 12
#define IMAGE_SUBSYSTEM_EFI_ROM 13
+/* DLL characteristics */
+#define IMAGE_DLLCHARACTERISTICS_NX_COMPAT 0x100
+
/* Section flags */
#define IMAGE_SCN_CNT_CODE 0x00000020
#define IMAGE_SCN_CNT_INITIALIZED_DATA 0x00000040