| From foo@baz Wed Nov 21 18:50:25 CET 2018 |
| From: Matthias Kaehlcke <mka@chromium.org> |
| Date: Thu, 17 Aug 2017 11:20:47 -0700 |
| Subject: x86/build: Use cc-option to validate stack alignment parameter |
| |
| From: Matthias Kaehlcke <mka@chromium.org> |
| |
| commit 9e8730b178a2472fca3123e909d6e69cc8127778 upstream. |
| |
| With the following commit: |
| |
| 8f91869766c0 ("x86/build: Fix stack alignment for CLang") |
| |
| cc-option is only used to determine the name of the stack alignment option |
| supported by the compiler, but not to verify that the actual parameter |
| <option>=N is valid in combination with the other CFLAGS. |
| |
| This causes problems (as reported by the kbuild robot) with older GCC versions |
| which only support stack alignment on a boundary of 16 bytes or higher. |
| |
| Also use (__)cc_option to add the stack alignment option to CFLAGS to |
| make sure only valid options are added. |
| |
| Reported-by: kbuild test robot <fengguang.wu@intel.com> |
| Signed-off-by: Matthias Kaehlcke <mka@chromium.org> |
| Cc: Arnd Bergmann <arnd@arndb.de> |
| Cc: Bernhard.Rosenkranzer@linaro.org |
| Cc: Greg Hackmann <ghackmann@google.com> |
| Cc: Kees Cook <keescook@chromium.org> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Masahiro Yamada <yamada.masahiro@socionext.com> |
| Cc: Michael Davidson <md@google.com> |
| Cc: Nick Desaulniers <ndesaulniers@google.com> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Stephen Hines <srhines@google.com> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: dianders@chromium.org |
| Fixes: 8f91869766c0 ("x86/build: Fix stack alignment for CLang") |
| Link: http://lkml.kernel.org/r/20170817182047.176752-1-mka@chromium.org |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/x86/Makefile | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/arch/x86/Makefile |
| +++ b/arch/x86/Makefile |
| @@ -38,7 +38,7 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os |
| |
| REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding) |
| REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector) |
| -REALMODE_CFLAGS += $(cc_stack_align4) |
| +REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align4)) |
| export REALMODE_CFLAGS |
| |
| # BITS is used as extension for files which are available in a 32 bit |
| @@ -78,7 +78,7 @@ ifeq ($(CONFIG_X86_32),y) |
| # Align the stack to the register width instead of using the default |
| # alignment of 16 bytes. This reduces stack usage and the number of |
| # alignment instructions. |
| - KBUILD_CFLAGS += $(cc_stack_align4) |
| + KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align4)) |
| |
| # Disable unit-at-a-time mode on pre-gcc-4.0 compilers, it makes gcc use |
| # a lot more stack due to the lack of sharing of stacklots: |
| @@ -117,7 +117,7 @@ else |
| # default alignment which keep the stack *mis*aligned. |
| # Furthermore an alignment to the register width reduces stack usage |
| # and the number of alignment instructions. |
| - KBUILD_CFLAGS += $(cc_stack_align8) |
| + KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align8)) |
| |
| # Use -mskip-rax-setup if supported. |
| KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup) |