On Thu, Sep 29, 2022 at 8:20 AM Nathan Chancellor nathan@kernel.org wrote:
A recent change in LLVM made CONFIG_EFI_STUB unselectable because it no longer pretends to support '-mabi=ms', breaking the dependency in Kconfig. Lack of CONFIG_EFI_STUB can prevent kernels from booting via EFI in certain circumstances.
This check was added by commit 8f24f8c2fc82 ("efi/libstub: Annotate firmware routines as __efiapi") to ensure that '__attribute__((ms_abi))' was available, as '-mabi=ms' is not actually used in any cflags. According to the GCC documentation, this attribute has been supported since GCC 4.4.7. The kernel currently requires GCC 5.1 so this check is not necessary; even when that change landed in 5.6, the kernel required GCC 4.9 so it was unnecessary then as well. Clang supports '__attribute__((ms_abi))' for all versions that are supported for building the kernel so no additional check is needed. Remove the 'depends on' line altogether to allow CONFIG_EFI_STUB to be selected when CONFIG_EFI is enabled, regardless of compiler.
Cc: stable@vger.kernel.org Fixes: 8f24f8c2fc82 ("efi/libstub: Annotate firmware routines as __efiapi") Link: https://github.com/ClangBuiltLinux/linux/issues/1725 Link: https://gcc.gnu.org/onlinedocs/gcc-4.4.7/gcc/Function-Attributes.html Link: https://github.com/llvm/llvm-project/commit/d1ad006a8f64bdc17f618deffa9e7c91... Signed-off-by: Nathan Chancellor nathan@kernel.org
Thanks for the patch! Reviewed-by: Nick Desaulniers ndesaulniers@google.com
arch/x86/Kconfig | 1 - 1 file changed, 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f9920f1341c8..81012154d9ed 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1956,7 +1956,6 @@ config EFI config EFI_STUB bool "EFI stub support" depends on EFI
depends on $(cc-option,-mabi=ms) || X86_32 select RELOCATABLE help This kernel feature allows a bzImage to be loaded directlybase-commit: f76349cf41451c5c42a99f18a9163377e4b364ff
2.37.3