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Date:   Thu, 1 Nov 2018 10:50:02 +0100
From:   Ingo Molnar <mingo@kernel.org>
To:     Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc:     linux-kernel@vger.kernel.org, mingo@redhat.com,
        konrad.wilk@oracle.com, luto@kernel.org, tglx@linutronix.de,
        dwmw@amazon.co.uk, bp@suse.de, srinivas.eeda@oracle.com,
        daniel@iogearbox.net, yamada.masahiro@socionext.com,
        michal.lkml@markovi.net, peterz@infradead.org, hpa@zytor.com
Subject: Re: [PATCH v2 1/2] retpolines: Only enable retpoline support when
 compiler support it
Message-ID: <20181101095002.GA118944@gmail.com>
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* Zhenzhong Duan <zhenzhong.duan@oracle.com> wrote:

> Since retpoline capable compilers are widely available, make
> CONFIG_RETPOLINE hard depend on it.
> 
> The check of RETPOLINE is changed to CONFIG_RETPOLINE.
> 
> This change is based on suggestion in https://lkml.org/lkml/2018/9/18/1016
>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>

Please turn such 'based on suggestions' into proper tags as well, i.e. 
something like:

  Suggested-by: David Woodhouse <dwmw2@infradead.org>

>  config RETPOLINE
>  	bool "Avoid speculative indirect branches in kernel"
> +	depends on $(cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register) || \
> +                    $(cc-option,-mretpoline-external-thunk)

At least a comment should be added that this is the retpoline feature 
check for GCC and Clang.

Also, whitespace damage plus the two options should align vertically.

Thanks,

	Ingo