From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DFF431C6B4; Sun, 14 Apr 2024 22:43:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=150.107.74.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713134591; cv=none; b=W3HjHmPD2obmPXAZ+qL/x6xUv46sOk4p+XwrrDQ5LsET1dmG+j/Gwh5LGWQfEEmaoOb00NTWy36t7YpvgYTjirYbUoJ+nqarvmsdJg3t9XGN9K/m9j4Lkgn8l7RZblFy0iNs3xFk5GBeyDNVJQJ1PyYZ6xjZTWZjCzgiEb5JIBA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713134591; c=relaxed/simple; bh=hgknNj1CMqAtlwoHGwSVuod75mSwIWNcQ2rwim3xtrY=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HglfIqEOEaJVX+wuUoqRqfa+FEqdHie9KLmKXwvZGtUzuh4a8LSylpNToM204dYI7Fp1jrIlabH6/Tnua/9yFTm/cYxY1s0mZjC8lRynKMz/cCFwceSDtQnG/Q8gogWrYCRs4fOEKjKYLt6qoS9d4qTepTuWdUSWRKn/ae2fTXs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=canb.auug.org.au; spf=pass smtp.mailfrom=canb.auug.org.au; dkim=pass (2048-bit key) header.d=canb.auug.org.au header.i=@canb.auug.org.au header.b=ooE7y/Qj; arc=none smtp.client-ip=150.107.74.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=canb.auug.org.au Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=canb.auug.org.au Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=canb.auug.org.au header.i=@canb.auug.org.au header.b="ooE7y/Qj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canb.auug.org.au; s=201702; t=1713134583; bh=4YxIT04d5iT4t/9CWLf2dJs39GSU2JGwBCGJMwje3e4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ooE7y/QjtRNgxNbD/iBXfW+vLDiRSXCPipXLjAPSVBegCGtlgGWZiackaWHNluCyN 5pU/pPht+GdlCVH7KenaDnUCSi76PMEKI8aZZE8n/2H2ge/wdXDEyNqNW3qJw17axm InHjB1XcIctesdyRBXNz4dcMJOI38JH9v0niQ+CbHZ676+tnh2VVRE3/Xbp4NE2xAh J5oYOFjdK5ffaKKQUcRrKJp4V6mjuq+p2ok1cG35PquEzalCDnOREc+hlQxDdjRvho jEuuOnL8CEEPNcpWKqAyZa2z4QjCLcZqZqMGlzBxjZaPB9Y5/Ykw7eucwjdX0shbJ0 MlMR8xtLzoDag== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4VHlgb16rBz4wcR; Mon, 15 Apr 2024 08:42:51 +1000 (AEST) Date: Mon, 15 Apr 2024 08:42:50 +1000 From: Stephen Rothwell To: Sean Christopherson Cc: Michael Ellerman , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Peter Zijlstra , Josh Poimboeuf , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Pawan Gupta , Daniel Sneddon , linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, Catalin Marinas , Will Deacon , Heiko Carstens Subject: Re: [PATCH 1/3] x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n Message-ID: <20240415084250.7b00ea63@canb.auug.org.au> In-Reply-To: <87bk6dd2l4.fsf@mail.lhotse> References: <20240409175108.1512861-1-seanjc@google.com> <20240409175108.1512861-2-seanjc@google.com> <20240413115324.53303a68@canb.auug.org.au> <87edb9d33r.fsf@mail.lhotse> <87bk6dd2l4.fsf@mail.lhotse> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/hV./THoU9xeCGcZYyAV1HiA"; protocol="application/pgp-signature"; micalg=pgp-sha256 --Sig_/hV./THoU9xeCGcZYyAV1HiA Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi all, On Sat, 13 Apr 2024 19:38:47 +1000 Michael Ellerman wr= ote: > > Michael Ellerman writes: > > Stephen Rothwell writes: =20 > ... > >> On Tue, 9 Apr 2024 10:51:05 -0700 Sean Christopherson wrote: =20 > ... > >>> diff --git a/kernel/cpu.c b/kernel/cpu.c > >>> index 8f6affd051f7..07ad53b7f119 100644 > >>> --- a/kernel/cpu.c > >>> +++ b/kernel/cpu.c > >>> @@ -3207,7 +3207,8 @@ enum cpu_mitigations { > >>> }; > >>> =20 > >>> static enum cpu_mitigations cpu_mitigations __ro_after_init =3D > >>> - CPU_MITIGATIONS_AUTO; > >>> + IS_ENABLED(CONFIG_SPECULATION_MITIGATIONS) ? CPU_MITIGATIONS_AUTO : > >>> + CPU_MITIGATIONS_OFF; > >>> =20 > >>> static int __init mitigations_parse_cmdline(char *arg) > >>> { =20 >=20 > I think a minimal workaround/fix would be: >=20 > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig > index 2b8fd6bb7da0..290be2f9e909 100644 > --- a/drivers/base/Kconfig > +++ b/drivers/base/Kconfig > @@ -191,6 +191,10 @@ config GENERIC_CPU_AUTOPROBE > config GENERIC_CPU_VULNERABILITIES > bool >=20 > +config SPECULATION_MITIGATIONS > + def_bool y > + depends on !X86 > + > config SOC_BUS > bool > select GLOB The original commit is now in Linus' tree. --=20 Cheers, Stephen Rothwell --Sig_/hV./THoU9xeCGcZYyAV1HiA Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEENIC96giZ81tWdLgKAVBC80lX0GwFAmYcW+oACgkQAVBC80lX 0GzNlAf8CJkJCFVxONVRLci2DamLPZ4T4ZsMm4OWVge3NTf2ODxR5/6fodpWAuOx Z4FTB9mMAJeazuf6SM1+K6bxNw3KKkfD9iexpu/bGgFgwJdZnObQp3NzxxGodpLp sf9Fr8TjVXNjgXvmi0rCfLuBqZ3dfCxWSIWc1YgG1FgGdNu2XzEjYmllpmLqas2n HG31in38tgVrVuwKMsIKX5Ma/qGGXFSTRWE0NETTzgCXJJQnXfm9VEEVrRzEHnl0 OGT6Y7IrdqT6XA9Lck1W6X97inzLj0GDGCdQjaqYsNwgjY39jQWNyU1mzi8BZQJk CY2veoa0e7AKDZ7ZR/xMAebrEE7ahg== =91NG -----END PGP SIGNATURE----- --Sig_/hV./THoU9xeCGcZYyAV1HiA--