From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: [PATCH v2] x86/efi: Fix 3DNow optimization build failure in EFI stub Date: Tue, 5 Aug 2014 00:12:19 +0100 Message-ID: <1407193939-27813-1-git-send-email-matt@console-pimps.org> Return-path: Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "H. Peter Anvin" Cc: Ingo Molnar , linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Matt Fleming , Borislav Petkov , Thomas Gleixner List-Id: linux-efi@vger.kernel.org From: Matt Fleming Building a 32-bit kernel with CONFIG_X86_USE_3DNOW and CONFIG_EFI_STUB leads to the following build error, drivers/firmware/efi/libstub/lib.a(efi-stub-helper.o): In function `efi_relocate_kernel': efi-stub-helper.c:(.text+0xda5): undefined reference to `_mmx_memcpy' This is due to the fact that the EFI boot stub pulls in the 3DNow optimized versions of the memcpy() prototype from arch/x86/include/asm/string_32.h, even though the _mmx_memcpy() implementation isn't available in the EFI stub. For now, predicate CONFIG_EFI_STUB on !CONFIG_X86_USE_3DNOW. This is most definitely a temporary fix. A complete solution will involve selectively including kernel headers/symbols into the early-boot execution environment of the EFI boot stub, i.e. something analogous to the way that the _SETUP symbol is used. Previous attempts have been made to fix this kind of problem, though none seem to have ever been merged, http://lkml.kernel.org/r/20120329104822.GA17233-eWLsEhkZJs/kLsZ8J5Uweg@public.gmane.org Clearly, this problem has been around for a long time. Reported-by: Ingo Molnar Cc: H. Peter Anvin Cc: Borislav Petkov Cc: Thomas Gleixner Signed-off-by: Matt Fleming --- v2: Only disallow CONFIG_X86_USE_3DNOW for EFI_STUB, not for the EFI runtime services. diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 801ed36c2e49..7ea8aaaab7fc 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1536,7 +1536,7 @@ config EFI config EFI_STUB bool "EFI stub support" - depends on EFI + depends on EFI && !X86_USE_3DNOW ---help--- This kernel feature allows a bzImage to be loaded directly by EFI firmware without the use of a bootloader. -- 1.9.0