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Groups > linux.kernel > #1666932
| From | Matthias Kaehlcke <mka@chromium.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 2/3] x86/build: Use __cc-option for boot code compiler options |
| Date | 2017-06-15 19:50 +0200 |
| Message-ID | <tSH46-5q5-9@gated-at.bofh.it> (permalink) |
| References | <tSH45-5q5-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
cc-option is used to enable compiler options for the boot code if they are available. The macro uses KBUILD_CFLAGS and KBUILD_CPPFLAGS for the check, however 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 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 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@chromium.org> --- Changes in v3: - Use __cc-option instead of cc-option-raw - Updated commit message arch/x86/Makefile | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index bf240b920473..b2dae639f778 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, $(CC), $(REALMODE_CFLAGS), -ffreestanding) +REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector) +REALMODE_CFLAGS += $(call __cc-option, $(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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[PATCH v3 0/3] x86: stack alignment for boot code and clang Matthias Kaehlcke <mka@chromium.org> - 2017-06-15 19:50 +0200
[PATCH v3 2/3] x86/build: Use __cc-option for boot code compiler options Matthias Kaehlcke <mka@chromium.org> - 2017-06-15 19:50 +0200
[PATCH v3 1/3] kbuild: Add __cc-option macro Matthias Kaehlcke <mka@chromium.org> - 2017-06-15 19:50 +0200
Re: [PATCH v3 1/3] kbuild: Add __cc-option macro Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-16 02:50 +0200
Re: [PATCH v3 1/3] kbuild: Add __cc-option macro kbuild test robot <lkp@intel.com> - 2017-06-18 09:00 +0200
Re: [PATCH v3 1/3] kbuild: Add __cc-option macro Masahiro Yamada <yamada.masahiro@socionext.com> - 2017-06-19 04:10 +0200
Re: [PATCH v3 1/3] kbuild: Add __cc-option macro Matthias Kaehlcke <mka@chromium.org> - 2017-06-19 18:50 +0200
[PATCH v3 3/3] x86/build: Specify stack alignment for clang Matthias Kaehlcke <mka@chromium.org> - 2017-06-15 19:50 +0200
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