From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>,
lersek@redhat.com, leif@nuviainc.com, pjones@redhat.com,
mjg59@google.com, agraf@csgraf.de, ilias.apalodimas@linaro.org,
xypron.glpk@gmx.de, daniel.kiper@oracle.com,
nivedita@alum.mit.edu, James.Bottomley@hansenpartnership.com
Subject: [RFC PATCH 3/3] efi: Bump the Linux EFI stub major version number to #1
Date: Thu, 20 Feb 2020 12:06:49 +0100 [thread overview]
Message-ID: <20200220110649.1303-4-ardb@kernel.org> (raw)
In-Reply-To: <20200220110649.1303-1-ardb@kernel.org>
Now that we have introduced new, generic ways for the OS loader to
interface with Linux kernels during boot, we need to record this
fact in a way that allows loaders to discover this information, and
fall back to the existing methods for older kernels.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
include/linux/pe.h | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/include/linux/pe.h b/include/linux/pe.h
index e0869f3eadd6..8ad71d763a77 100644
--- a/include/linux/pe.h
+++ b/include/linux/pe.h
@@ -10,7 +10,25 @@
#include <linux/types.h>
-#define LINUX_EFISTUB_MAJOR_VERSION 0x0
+/*
+ * Linux EFI stub v1.0 adds the following functionality:
+ * - Loading initrd from the LINUX_EFI_INITRD_MEDIA_GUID device path,
+ * - Loading/starting the kernel from firmware that targets a different
+ * machine type, via the entrypoint exposed in the .compat PE/COFF section.
+ *
+ * The recommended way of loading and starting v1.0 or later kernels is to use
+ * the LoadImage() and StartImage() EFI boot services, and expose the initrd
+ * via the LINUX_EFI_INITRD_MEDIA_GUID device path.
+ *
+ * Versions older than v1.0 support initrd loading via the image load options
+ * (using initrd=, limited to the volume from which the kernel itself was
+ * loaded), or via arch specific means (bootparams, DT, etc).
+ *
+ * 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.
+ */
+#define LINUX_EFISTUB_MAJOR_VERSION 0x1
#define LINUX_EFISTUB_MINOR_VERSION 0x0
#define MZ_MAGIC 0x5a4d /* "MZ" */
--
2.17.1
next prev parent reply other threads:[~2020-02-20 11:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 11:06 [RFC PATCH 0/3] efi: put an API version number in the PE/COFF header Ard Biesheuvel
2020-02-20 11:06 ` [RFC PATCH 1/3] efi/x86: Use symbolic constants in PE header instead of bare numbers Ard Biesheuvel
2020-02-20 17:28 ` Arvind Sankar
2020-02-20 17:32 ` Ard Biesheuvel
2020-02-20 18:04 ` Arvind Sankar
2020-02-20 18:11 ` Arvind Sankar
2020-02-20 18:14 ` Ard Biesheuvel
2020-02-20 19:33 ` Arvind Sankar
2020-02-20 19:51 ` Arvind Sankar
2020-02-20 21:22 ` Ard Biesheuvel
2020-02-20 22:04 ` Arvind Sankar
2020-02-20 11:06 ` [RFC PATCH 2/3] efi/libstub: Introduce symbolic constants for the stub major/minor version Ard Biesheuvel
2020-02-20 11:06 ` Ard Biesheuvel [this message]
2020-02-20 13:53 ` [RFC PATCH 0/3] efi: put an API version number in the PE/COFF header Daniel Kiper
2020-02-20 14:55 ` Heinrich Schuchardt
2020-02-20 19:29 ` Ard Biesheuvel
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