efi/libstub: Introduce symbolic constants for the stub major/minor version

Now that we have added new ways to load the initrd or the mixed mode
kernel, we will also need a way to tell the loader about this. Add
symbolic constants for the PE/COFF major/minor version numbers (which
fortunately have always been 0x0 for all architectures), so that we
can bump them later to document the capabilities of the stub.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

arch/arm/boot/compressed/efi-header.S

@@ -70,8 +70,8 @@ extra_header_fields:
 		.long	SZ_512				@ FileAlignment
 		.short	0				@ MajorOsVersion
 		.short	0				@ MinorOsVersion
-		.short	0				@ MajorImageVersion
-		.short	0				@ MinorImageVersion
+		.short	LINUX_EFISTUB_MAJOR_VERSION	@ MajorImageVersion
+		.short	LINUX_EFISTUB_MINOR_VERSION	@ MinorImageVersion
 		.short	0				@ MajorSubsystemVersion
 		.short	0				@ MinorSubsystemVersion
 		.long	0				@ Win32VersionValue

arch/arm64/kernel/efi-header.S

@@ -36,8 +36,8 @@ extra_header_fields:
 	.long	PECOFF_FILE_ALIGNMENT			// FileAlignment
 	.short	0					// MajorOperatingSystemVersion
 	.short	0					// MinorOperatingSystemVersion
-	.short	0					// MajorImageVersion
-	.short	0					// MinorImageVersion
+	.short	LINUX_EFISTUB_MAJOR_VERSION		// MajorImageVersion
+	.short	LINUX_EFISTUB_MINOR_VERSION		// MinorImageVersion
 	.short	0					// MajorSubsystemVersion
 	.short	0					// MinorSubsystemVersion
 	.long	0					// Win32VersionValue

arch/x86/boot/header.S

@@ -147,8 +147,8 @@ extra_header_fields:
 	.long	0x20				# FileAlignment
 	.word	0				# MajorOperatingSystemVersion
 	.word	0				# MinorOperatingSystemVersion
-	.word	0				# MajorImageVersion
-	.word	0				# MinorImageVersion
+	.word	LINUX_EFISTUB_MAJOR_VERSION	# MajorImageVersion
+	.word	LINUX_EFISTUB_MINOR_VERSION	# MinorImageVersion
 	.word	0				# MajorSubsystemVersion
 	.word	0				# MinorSubsystemVersion
 	.long	0				# Win32VersionValue

include/linux/pe.h

@@ -10,6 +10,9 @@
 
 #include <linux/types.h>
 
+#define LINUX_EFISTUB_MAJOR_VERSION		0x0
+#define LINUX_EFISTUB_MINOR_VERSION		0x0
+
 #define MZ_MAGIC	0x5a4d	/* "MZ" */
 
 #define PE_MAGIC		0x00004550	/* "PE\0\0" */