* tip-bot2 for Nick Desaulniers <tip-bot2@xxxxxxxxxxxxx> 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@xxxxxxxxxx>
> AuthorDate: Thu, 12 Aug 2021 11:38:48 -07:00
> Committer: Borislav Petkov <bp@xxxxxxx>
> 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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