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
Date: Thu, 1 Nov 2018 10:50:02 +0100 [thread overview]
Message-ID: <20181101095002.GA118944@gmail.com> (raw)
In-Reply-To: <991cbe9b-1e31-4b12-b572-91fde5c79699@default>
* 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
next prev parent reply other threads:[~2018-11-01 9:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-01 9:31 [PATCH v2 1/2] retpolines: Only enable retpoline support when compiler support it Zhenzhong Duan
2018-11-01 9:50 ` Ingo Molnar [this message]
[not found] ` <90a9eed724b28d5af57a71694a95b4cd92728ccc.camel@amazon.co.uk>
2018-11-01 12:17 ` Thomas Gleixner
2018-11-01 14:34 ` Ingo Molnar
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