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Date:   Fri, 22 May 2020 12:26:31 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Marco Elver <elver@google.com>
Cc:     paulmck@kernel.org, dvyukov@google.com, glider@google.com,
        andreyknvl@google.com, kasan-dev@googlegroups.com,
        linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org,
        peterz@infradead.org, will@kernel.org,
        clang-built-linux@googlegroups.com
Subject: Re: [PATCH -tip v3 03/11] kcsan: Support distinguishing volatile
 accesses
Message-ID: <20200522102630.GC28750@zn.tnic>
References: <20200521142047.169334-1-elver@google.com>
 <20200521142047.169334-4-elver@google.com>
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On Thu, May 21, 2020 at 04:20:39PM +0200, Marco Elver wrote:
> diff --git a/scripts/Makefile.kcsan b/scripts/Makefile.kcsan
> index 20337a7ecf54..75d2942b9437 100644
> --- a/scripts/Makefile.kcsan
> +++ b/scripts/Makefile.kcsan
> @@ -9,7 +9,10 @@ else
>  cc-param = --param -$(1)
>  endif
>  
> +# Keep most options here optional, to allow enabling more compilers if absence
> +# of some options does not break KCSAN nor causes false positive reports.
>  CFLAGS_KCSAN := -fsanitize=thread \
> -	$(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0) -fno-optimize-sibling-calls)
> +	$(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0) -fno-optimize-sibling-calls) \
> +	$(call cc-param,tsan-distinguish-volatile=1)

gcc 9 doesn't like this:

cc1: error: invalid --param name ‘-tsan-distinguish-volatile’
make[1]: *** [scripts/Makefile.build:100: scripts/mod/devicetable-offsets.s] Error 1
make[1]: *** Waiting for unfinished jobs....
cc1: error: invalid --param name ‘-tsan-distinguish-volatile’
make[1]: *** [scripts/Makefile.build:267: scripts/mod/empty.o] Error 1
make: *** [Makefile:1141: prepare0] Error 2
make: *** Waiting for unfinished jobs....

git grep "tsan-distinguish-volatile" in gcc's git doesn't give anything.

Hmm.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette