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Date: Tue, 13 Jun 2017 16:08:53 -0700 From: Matthias Kaehlcke <mka@...omium.org> To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "H . Peter Anvin" <hpa@...or.com>, "H . J . Lu" <hjl.tools@...il.com>, David Woodhouse <dwmw2@...radead.org>, Masahiro Yamada <yamada.masahiro@...ionext.com>, Michal Marek <mmarek@...e.com> Cc: x86@...nel.org, linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org, Michael Davidson <md@...gle.com>, Greg Hackmann <ghackmann@...gle.com>, Nick Desaulniers <ndesaulniers@...gle.com>, Stephen Hines <srhines@...gle.com>, Kees Cook <keescook@...omium.org>, Arnd Bergmann <arnd@...db.de>, Bernhard.Rosenkranzer@...aro.org, Peter Foley <pefoley2@...oley.com>, Behan Webster <behanw@...verseincode.com>, Douglas Anderson <dianders@...omium.org>, Matthias Kaehlcke <mka@...omium.org> Subject: [PATCH v2 3/4] x86/build: Use cc-option-raw for boot code compiler options cc-option uses KBUILD_CFLAGS and KBUILD_CPPFLAGS when checking if a compiler option is available. These flags aren't used to build the boot code, in consequence cc-option can yield wrong results. For example -mpreferred-stack-boundary=2 is never set with a 64 bit compiler, since the setting is only valid for 16 and 32 bit binaries. This is also the case for 32 bit kernel builds, because the option -m32 is added to KBUILD_CFLAGS after the assignment of REALMODE_CFLAGS. Use cc-option-raw instead of cc-option for the boot mode options. The macro receives the compiler options as parameter instead of using KBUILD_C*FLAGS. For the boot code we pass REALMODE_CFLAGS. Also use separate statements for the cc-option-raw checks instead of performing them in the initial assignment of REALMODE_CFLAGS since the variable is an input of the macro. Signed-off-by: Matthias Kaehlcke <mka@...omium.org> --- Changes in v2: - Adapted to use kbuild macro cc-option-raw instead of cc-option-no-kbuild arch/x86/Makefile | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index bf240b920473..6d3ae4b20a5b 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -24,10 +24,11 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -D__KERNEL__ \ -DDISABLE_BRANCH_PROFILING \ -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \ -fno-strict-aliasing -fomit-frame-pointer -fno-pic \ - -mno-mmx -mno-sse \ - $(call cc-option, -ffreestanding) \ - $(call cc-option, -fno-stack-protector) \ - $(call cc-option, -mpreferred-stack-boundary=2) + -mno-mmx -mno-sse + +REALMODE_CFLAGS += $(call cc-option-raw, $(CC), $(REALMODE_CFLAGS), -ffreestanding) +REALMODE_CFLAGS += $(call cc-option-raw, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector) +REALMODE_CFLAGS += $(call cc-option-raw, $(CC), $(REALMODE_CFLAGS), -mpreferred-stack-boundary=2) export REALMODE_CFLAGS # BITS is used as extension for files which are available in a 32 bit -- 2.13.1.518.g3df882009-goog
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