From: Ingo Molnar <mingo@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "Woodhouse, David" <dwmw@amazon.co.uk>,
"zhenzhong.duan@oracle.com" <zhenzhong.duan@oracle.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
"peterz@infradead.org" <peterz@infradead.org>,
"bp@suse.de" <bp@suse.de>,
"srinivas.eeda@oracle.com" <srinivas.eeda@oracle.com>,
"konrad.wilk@oracle.com" <konrad.wilk@oracle.com>,
"michal.lkml@markovi.net" <michal.lkml@markovi.net>,
"hpa@zytor.com" <hpa@zytor.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"yamada.masahiro@socionext.com" <yamada.masahiro@socionext.com>,
"luto@kernel.org" <luto@kernel.org>
Subject: Re: [PATCH v2 1/2] retpolines: Only enable retpoline support when compiler support it
Date: Thu, 1 Nov 2018 15:34:21 +0100 [thread overview]
Message-ID: <20181101143421.GA81370@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1811011317400.1642@nanos.tec.linutronix.de>
* Thomas Gleixner <tglx@linutronix.de> wrote:
> On Thu, 1 Nov 2018, Woodhouse, David wrote:
> > On Thu, 2018-11-01 at 10:50 +0100, Ingo Molnar wrote:
> > > * 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>
> >
> > I think the suggestion came from PeterZ; I just acked it.
> >
> > Although on furthe reflection, I think I'd prefer a build break if
> > retpoline is enabled in the kernel config and the compiler doesn't
> > support it. This patch would make it silently fail to be secure.
>
> Agreed.
Yeah, I agree that that's the best policy: if someone wants retpoline
support it shouldn't silently turn off just because the wrong toolchain
was used to build the kernel ...
Thanks,
Ingo
prev parent reply other threads:[~2018-11-01 14:34 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
[not found] ` <90a9eed724b28d5af57a71694a95b4cd92728ccc.camel@amazon.co.uk>
2018-11-01 12:17 ` Thomas Gleixner
2018-11-01 14:34 ` Ingo Molnar [this message]
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