efi: Make it possible to disable efivar_ssdt entirely (435d1a47) · Commits · 戴 / test

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>

drivers/firmware/efi/Kconfig

+11 −0

Original line number	Diff line number	Diff line
		@@ -278,3 +278,14 @@ 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.

drivers/firmware/efi/efi.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -189,7 +189,7 @@ 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)

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