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Message-ID: <CAG8fp8Te=oT1JJhTpOZvgWJrgcTq2DXan8UOVZ=KYCYNa8cKog@mail.gmail.com>
Date: Sun, 28 May 2023 16:58:57 +0900
From: Akihiro Suda <suda.kyoto@...il.com>
To: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Ard Biesheuvel <ardb@...nel.org>, linux-efi@...r.kernel.org,
Linux x86 <x86@...nel.org>
Subject: [PATCH] efi: bump efistub version from 1.1 to 3.0 for
VZLinuxBootLoader compatibility
- LINUX_EFISTUB_MAJOR_VERSION is bumped from 1 (0b1) to 3 (0b11).
The value is now a bitfield. The next version will be 7 (0b111).
- LINUX_EFISTUB_MINOR_VERSION is pinned to 0x0, because Apple's
VZLinuxBootLoader [1] cannot boot a kernel with other minor version value [2],
even though it does not use UEFI. Tested with macOS 13.4 (x86_64).
[1] https://developer.apple.com/documentation/virtualization/vzlinuxbootloader
[2] https://lore.kernel.org/linux-efi/CAG8fp8Teu4G9JuenQrqGndFt2Gy+V4YgJ=hN1xX7AD940YKf3A@mail.gmail.com/
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217485
Signed-off-by: Akihiro Suda <akihiro.suda.cz@....ntt.co.jp>
---
include/linux/pe.h | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/include/linux/pe.h b/include/linux/pe.h
index 5e1e11540870..ee5ade19b7eb 100644
--- a/include/linux/pe.h
+++ b/include/linux/pe.h
@@ -27,9 +27,25 @@
* On x86, LoadImage() and StartImage() can be omitted if the EFI handover
* protocol is implemented, which can be inferred from the version,
* handover_offset and xloadflags fields in the bootparams structure.
+ *
+ * Linux EFI stub v1.1 unconditionally enabled initrd command line loader,
+ * which was previously gated by CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER.
+ *
+ * Linux EFI stub v3.0 changed the major version to be a bitfield (0b11).
+ * The rightmost bit means that it is compatible with v1.0 at least.
+ * The second rightmost bit means that initrd command line loader is enabled.
+ * So, there is no v2.0 (0b10), and the next version will be v7.0 (0b111).
+ */
+#define LINUX_EFISTUB_MAJOR_VERSION 0x3
+
+/*
+ * LINUX_EFISTUB_MINOR_VERSION is pinned to 0x0, because Apple's
+ * VZLinuxBootLoader cannot boot a kernel with other minor version value, even
+ * though it does not use UEFI. Tested with macOS 13.4 (x86_64).
+ *
+ * https://lore.kernel.org/linux-efi/CAG8fp8Teu4G9JuenQrqGndFt2Gy+V4YgJ=hN1xX7AD940YKf3A@mail.gmail.com/
*/
-#define LINUX_EFISTUB_MAJOR_VERSION 0x1
-#define LINUX_EFISTUB_MINOR_VERSION 0x1
+#define LINUX_EFISTUB_MINOR_VERSION 0x0
/*
* LINUX_PE_MAGIC appears at offset 0x38 into the MS-DOS header of EFI bootable
--
2.39.2
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