linux-kernel - [PATCH 6/7] efi: efivars: limit availability to X86 builds

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Message-Id: <20200923161404.17811-7-ardb@kernel.org>
Date:   Wed, 23 Sep 2020 18:14:03 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     linux-kernel@...r.kernel.org
Cc:     linux-efi@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
        Matthew Garrett <mjg59@...gle.com>,
        Peter Jones <pjones@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Anton Vorontsov <anton@...msg.org>,
        Colin Cross <ccross@...roid.com>,
        Tony Luck <tony.luck@...el.com>
Subject: [PATCH 6/7] efi: efivars: limit availability to X86 builds

CONFIG_EFI_VARS controls the code that exposes EFI variables via
sysfs entries, which was deprecated before support for non-Intel
architectures was added to EFI. So let's limit its availability
to Intel architectures for the time being, and hopefully remove
it entirely in the not too distant future.

Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
---
 Documentation/arm/uefi.rst   |  2 +-
 drivers/firmware/efi/Kconfig | 13 ++++---------
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/Documentation/arm/uefi.rst b/Documentation/arm/uefi.rst
index f868330df6be..f732f957421f 100644
--- a/Documentation/arm/uefi.rst
+++ b/Documentation/arm/uefi.rst
@@ -23,7 +23,7 @@ makes it possible for the kernel to support additional features:
 For actually enabling [U]EFI support, enable:
 
 - CONFIG_EFI=y
-- CONFIG_EFI_VARS=y or m
+- CONFIG_EFIVAR_FS=y or m
 
 The implementation depends on receiving information about the UEFI environment
 in a Flattened Device Tree (FDT) - so is only available with CONFIG_OF.
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 80f5c67e3638..da1887f72a51 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -4,20 +4,15 @@ menu "EFI (Extensible Firmware Interface) Support"
 
 config EFI_VARS
 	tristate "EFI Variable Support via sysfs"
-	depends on EFI
+	depends on EFI && (X86 || IA64)
 	default n
 	help
 	  If you say Y here, you are able to get EFI (Extensible Firmware
 	  Interface) variable information via sysfs.  You may read,
 	  write, create, and destroy EFI variables through this interface.
-
-	  Note that using this driver in concert with efibootmgr requires
-	  at least test release version 0.5.0-test3 or later, which is
-	  available from:
-	  <http://linux.dell.com/efibootmgr/testing/efibootmgr-0.5.0-test3.tar.gz>
-
-	  Subsequent efibootmgr releases may be found at:
-	  <http://github.com/vathpela/efibootmgr>
+	  Note that this driver is only retained for compatibility with
+	  legacy users: new users should use the efivarfs filesystem
+	  instead.
 
 config EFI_ESRT
 	bool
-- 
2.17.1