Commit-ID: 9e8730b178a2472fca3123e909d6e69cc8127778
Gitweb: http://git.kernel.org/tip/9e8730b178a2472fca3123e909d6e69cc8127778
Author: Matthias Kaehlcke <[email protected]>
AuthorDate: Thu, 17 Aug 2017 11:20:47 -0700
Committer: Ingo Molnar <[email protected]>
CommitDate: Mon, 21 Aug 2017 09:53:15 +0200
x86/build: Use cc-option to validate stack alignment parameter
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 <[email protected]>
Signed-off-by: Matthias Kaehlcke <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: [email protected]
Cc: Greg Hackmann <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Michael Davidson <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephen Hines <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Fixes: 8f91869766c0 ("x86/build: Fix stack alignment for CLang")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/Makefile | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 48f3ae7..6276572 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -38,7 +38,7 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -D__KERNEL__ \
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)
