blob: 9fd49c93ee6357a91e93ada0087ad192983c4213 [file] [log] [blame]
From 640d12df5c2531c7028750d69447028443b758aa Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Mon, 15 Jun 2020 16:24:08 -0400
Subject: [PATCH] efi: Make it possible to disable efivar_ssdt entirely
commit 435d1a471598752446a72ad1201b3c980526d869 upstream.
In most cases, such as CONFIG_ACPI_CUSTOM_DSDT and
CONFIG_ACPI_TABLE_UPGRADE, boot-time modifications to firmware tables
are tied to specific Kconfig options. Currently this is not the case
for modifying the ACPI SSDT via the efivar_ssdt kernel command line
option and associated EFI variable.
This patch adds CONFIG_EFI_CUSTOM_SSDT_OVERLAYS, which defaults
disabled, in order to allow enabling or disabling that feature during
the build.
Cc: <stable@vger.kernel.org>
Signed-off-by: Peter Jones <pjones@redhat.com>
Link: https://lore.kernel.org/r/20200615202408.2242614-1-pjones@redhat.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index d4ea929e8b34..6fb498ac1aa5 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -205,3 +205,14 @@ config EFI_EARLYCON
depends on SERIAL_EARLYCON && !ARM && !IA64
select FONT_SUPPORT
select ARCH_USE_MEMREMAP_PROT
+
+config EFI_CUSTOM_SSDT_OVERLAYS
+ bool "Load custom ACPI SSDT overlay from an EFI variable"
+ depends on EFI_VARS && ACPI
+ default ACPI_TABLE_UPGRADE
+ help
+ Allow loading of an ACPI SSDT overlay from an EFI variable specified
+ by a kernel command line option.
+
+ See Documentation/admin-guide/acpi/ssdt-overlays.rst for more
+ information.
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 185d24c8eb75..816d773378a2 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -236,7 +236,7 @@ static void generic_ops_unregister(void)
efivars_unregister(&generic_efivars);
}
-#if IS_ENABLED(CONFIG_ACPI)
+#ifdef CONFIG_EFI_CUSTOM_SSDT_OVERLAYS
#define EFIVAR_SSDT_NAME_MAX 16
static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata;
static int __init efivar_ssdt_setup(char *str)
--
2.27.0