From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>,
<xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 2/3] x86/clang: add retpoline support
Date: Wed, 16 Feb 2022 12:26:42 +0100 [thread overview]
Message-ID: <Ygzfcop5TrpeXfG1@Air-de-Roger> (raw)
In-Reply-To: <c5657f85-e3c4-9c39-1a67-b5162b1f86ef@suse.com>
On Wed, Feb 16, 2022 at 10:47:52AM +0100, Jan Beulich wrote:
> On 16.02.2022 10:02, Roger Pau Monne wrote:
> > Detect whether the compiler supports clang retpoline option and enable
> > by default if available, just like it's done for gcc.
> >
> > Note clang already disables jump tables when retpoline is enabled, so
> > there's no need to also pass the fno-jump-tables parameter.
>
> That's one of the secondary gcc side arrangements. What about the other
> (-mindirect-branch-register)?
clang already passes the return address on a register always on amd64
so that's not needed either. I can add a comment like I've done for
no-jump-tables.
> > Reported-by: Jan Beulich <JBeulich@suse.com>
>
> That's Andrew, not me?
Ops, sorry, I got that mixed up then.
Thanks, Roger.
next prev parent reply other threads:[~2022-02-16 11:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-16 9:02 [PATCH 0/3] retpoline: add clang support + Kconfig selectable Roger Pau Monne
2022-02-16 9:02 ` [PATCH 1/3] x86/retpoline: rename retpoline Kconfig check to include GCC prefix Roger Pau Monne
2022-02-16 9:45 ` Jan Beulich
2022-02-16 9:02 ` [PATCH 2/3] x86/clang: add retpoline support Roger Pau Monne
2022-02-16 9:47 ` Jan Beulich
2022-02-16 11:26 ` Roger Pau Monné [this message]
2022-02-16 14:07 ` Jan Beulich
2022-02-16 9:03 ` [PATCH 3/3] x86/Kconfig: introduce option to select retpoline usage Roger Pau Monne
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