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.
Signed-off-by: Peter Jones <pjo...@redhat.com>
---
drivers/firmware/efi/efi.c | 2 +-
drivers/firmware/efi/Kconfig | 11 +++++++++++
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 48d0188936c..4b12a598ccf 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -192,7 +192,7 @@ static void generic_ops_unregister(void)
efivars_unregister(&generic_efivars);
}
-#if IS_ENABLED(CONFIG_ACPI)
+#if IS_ENABLED(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)
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 6b38f9e5d20..fe433f76b03 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -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
+ 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.
--
2.26.2
