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From:   "Li, Xin3" <xin3.li@intel.com>
To:     Nathan Chancellor <nathan@kernel.org>
CC:     Peter Zijlstra <peterz@infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>,
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        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
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        "pbonzini@redhat.com" <pbonzini@redhat.com>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        "llvm@lists.linux.dev" <llvm@lists.linux.dev>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Kees Cook <keescook@chromium.org>
Subject: RE: [RESEND PATCH 2/6] x86/traps: add a system interrupt table for
 system interrupt dispatch
Thread-Topic: [RESEND PATCH 2/6] x86/traps: add a system interrupt table for
 system interrupt dispatch
Thread-Index: AQHY9M85Yu9uY6afW02HaiePlaJ2sq432uWAgAC2DaCAAAq8AIAADReAgAAaLxA=
Date:   Thu, 10 Nov 2022 23:00:51 +0000
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> > > > > +#pragma GCC diagnostic push
> > > > > +#pragma GCC diagnostic ignored "-Wcast-function-type"
> > > >
> > > > How does this not break CFI ?
> > >
> > > I wasn't aware of it, will check.
> >
> > CFI needs $(cc-option,-fsanitize=3Dkcfi), which, reported on LWN on Jun=
,
> > 2002, had not yet landed in the LLVM mainline (I'm using GCC).  So
> > looks we are replying on people keeping an eye on it to make sure it's =
not
> broken?
>=20
> Well, the entire point of the warning that you are disabling here is to c=
atch
> potential CFI failures at compile time, rather than run time :)

Oh, of course I didn't intend to be opposed to CFI.

>=20
> Clang also has -Wcast-function-type-strict, which Gustavo and Kees are wo=
rking
> on getting enabled, so that even more CFI failures can be caught at compi=
le
> time.
>=20
> https://github.com/ClangBuiltLinux/linux/issues/1724
> https://lore.kernel.org/all/?q=3D-Wcast-function-type-strict
>=20
> Cheers,
> Nathan