Re: [PATCH AUTOSEL 4.14 08/23] ARM: 8875/1: Kconfig: default to AEABI w/ Clang

[Sasha Levin]

On Sun, Sep 29, 2019 at 11:08:52AM -0700, Nathan Chancellor wrote:
> On Sun, Sep 29, 2019 at 01:35:18PM -0400, Sasha Levin wrote:
> > From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> >
> > [ Upstream commit a05b9608456e0d4464c6f7ca8572324ace57a3f4 ]
> >
> > Clang produces references to __aeabi_uidivmod and __aeabi_idivmod for
> > arm-linux-gnueabi and arm-linux-gnueabihf targets incorrectly when AEABI
> > is not selected (such as when OABI_COMPAT is selected).
> >
> > While this means that OABI userspaces wont be able to upgraded to
> > kernels built with Clang, it means that boards that don't enable AEABI
> > like s3c2410_defconfig will stop failing to link in KernelCI when built
> > with Clang.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/482
> > Link: https://groups.google.com/forum/#!msg/clang-built-linux/yydsAAux5hk/GxjqJSW-AQAJ
> >
> > Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> > Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
> > Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> >  arch/arm/Kconfig | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index cf69aab648fbd..f0080864b9ce8 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1595,8 +1595,9 @@ config ARM_PATCH_IDIV
> >  	  code to do integer division.
> >
> >  config AEABI
> > -	bool "Use the ARM EABI to compile the kernel" if !CPU_V7 && !CPU_V7M && !CPU_V6 && !CPU_V6K
> > -	default CPU_V7 || CPU_V7M || CPU_V6 || CPU_V6K
> > +	bool "Use the ARM EABI to compile the kernel" if !CPU_V7 && \
> > +		!CPU_V7M && !CPU_V6 && !CPU_V6K && !CC_IS_CLANG
> > +	default CPU_V7 || CPU_V7M || CPU_V6 || CPU_V6K || CC_IS_CLANG
> >  	help
> >  	  This option allows for the kernel to be compiled using the latest
> >  	  ARM ABI (aka EABI).  This is only useful if you are using a user
> > --
> > 2.20.1
>
> Hi Sasha,
>
> This patch will not do anything for 4.14 because CC_IS_CLANG is not
> defined in this tree. The Kconfig patches that make this symbol possible
> were not merged until 4.18. I would recommend dropping it (unless Nick
> has an idea to make this work).

I've dropped it from 4.14 and older, thanks!

--
Thanks,
Sasha