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Date:   Tue, 22 Oct 2019 13:59:22 +0100
From:   Mark Rutland <mark.rutland@arm.com>
To:     Marco Elver <elver@google.com>
Cc:     akiyks@gmail.com, stern@rowland.harvard.edu, glider@google.com,
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Subject: Re: [PATCH v2 8/8] x86, kcsan: Enable KCSAN for x86
Message-ID: <20191022125921.GD11583@lakrids.cambridge.arm.com>
References: <20191017141305.146193-1-elver@google.com>
 <20191017141305.146193-9-elver@google.com>
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On Thu, Oct 17, 2019 at 04:13:05PM +0200, Marco Elver wrote:
> This patch enables KCSAN for x86, with updates to build rules to not use
> KCSAN for several incompatible compilation units.
> 
> Signed-off-by: Marco Elver <elver@google.com>
> ---
> v2:
> * Document build exceptions where no previous above comment explained
>   why we cannot instrument.
> ---
>  arch/x86/Kconfig                      | 1 +
>  arch/x86/boot/Makefile                | 2 ++
>  arch/x86/boot/compressed/Makefile     | 2 ++
>  arch/x86/entry/vdso/Makefile          | 3 +++
>  arch/x86/include/asm/bitops.h         | 6 +++++-
>  arch/x86/kernel/Makefile              | 7 +++++++
>  arch/x86/kernel/cpu/Makefile          | 3 +++
>  arch/x86/lib/Makefile                 | 4 ++++
>  arch/x86/mm/Makefile                  | 3 +++
>  arch/x86/purgatory/Makefile           | 2 ++
>  arch/x86/realmode/Makefile            | 3 +++
>  arch/x86/realmode/rm/Makefile         | 3 +++
>  drivers/firmware/efi/libstub/Makefile | 2 ++
>  13 files changed, 40 insertions(+), 1 deletion(-)

> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index 0460c7581220..693d0a94b118 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -31,7 +31,9 @@ KBUILD_CFLAGS			:= $(cflags-y) -DDISABLE_BRANCH_PROFILING \
>  				   -D__DISABLE_EXPORTS
>  
>  GCOV_PROFILE			:= n
> +# Sanitizer runtimes are unavailable and cannot be linked here.
>  KASAN_SANITIZE			:= n
> +KCSAN_SANITIZE			:= n
>  UBSAN_SANITIZE			:= n
>  OBJECT_FILES_NON_STANDARD	:= y

Not a big deal, but it might make sense to move the EFI stub exception
to patch 3 since it isn't x86 specific (and will also apply for arm64).

Otherwise this looks good to me.

Thanks,
Mark.