Messages in this thread Patch in this message | | | Date | Sun, 22 Aug 2021 10:31:51 +0200 | From | Ingo Molnar <> | Subject | Re: [tip: x86/build] x86/build: Remove stale cc-option checks |
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* tip-bot2 for Nick Desaulniers <tip-bot2@linutronix.de> wrote:
> The following commit has been merged into the x86/build branch of tip: > > Commit-ID: 1463c2a27d59c69358ad1cbd869d3a8649695d8c > Gitweb: https://git.kernel.org/tip/1463c2a27d59c69358ad1cbd869d3a8649695d8c > Author: Nick Desaulniers <ndesaulniers@google.com> > AuthorDate: Thu, 12 Aug 2021 11:38:48 -07:00 > Committer: Borislav Petkov <bp@suse.de> > CommitterDate: Sun, 15 Aug 2021 10:32:52 +02:00 > > x86/build: Remove stale cc-option checks > > -mpreferred-stack-boundary= is specific to GCC, while -mstack-alignment= > is specific to Clang. Rather than test for this three times via > cc-option and __cc-option, rely on CONFIG_CC_IS_* from Kconfig. > > GCC did not support values less than 4 for -mpreferred-stack-boundary= > until GCC 7+. Change the cc-option test to check for a value of 2, > rather than 4.
> --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -14,10 +14,13 @@ endif > > # For gcc stack alignment is specified with -mpreferred-stack-boundary, > # clang has the option -mstack-alignment for that purpose. > -ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) > +ifdef CONFIG_CC_IS_GCC > +ifneq ($(call cc-option, -mpreferred-stack-boundary=2),) > cc_stack_align4 := -mpreferred-stack-boundary=2 > cc_stack_align8 := -mpreferred-stack-boundary=3 > -else ifneq ($(call cc-option, -mstack-alignment=16),) > +endif > +endif > +ifdef CONFIG_CC_IS_CLANG > cc_stack_align4 := -mstack-alignment=4 > cc_stack_align8 := -mstack-alignment=8
So I spent most of yesterday bisecting a hard to diagnose bug that looked like a GPU driver bug - but the bisect somewhat surprisingly ended up at this commit.
Doing the partial revert below solves the regression - as the above hunk is not obviously an identity transformation. I have a pretty usual GCC 10.3.0 build environment with nothing exotic.
I amdended the commit with the partial revert in tip:x86/build.
Thanks,
Ingo
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 0d33ba013683..88fb2bca6a3e 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -14,13 +14,10 @@ endif # For gcc stack alignment is specified with -mpreferred-stack-boundary, # clang has the option -mstack-alignment for that purpose. -ifdef CONFIG_CC_IS_GCC -ifneq ($(call cc-option, -mpreferred-stack-boundary=2),) +ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) cc_stack_align4 := -mpreferred-stack-boundary=2 cc_stack_align8 := -mpreferred-stack-boundary=3 -endif -endif -ifdef CONFIG_CC_IS_CLANG +else ifneq ($(call cc-option, -mstack-alignment=16),) cc_stack_align4 := -mstack-alignment=4 cc_stack_align8 := -mstack-alignment=8 endif
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