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Ly" , "Naveen N. Rao" , Daniel Axtens , Nicholas Piggin , =?iso-8859-1?Q?C=E9dric_Le_Goater?= , David Gibson , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , Sergey Senozhatsky , Masami Hiramatsu , Andrew Donnellan , Philippe Ombredanne , Joe Perches , Oliver O'Halloran , Andrew Morton , "Tobin C. Harding" Subject: Re: [PATCH RFC rebase 9/9] powerpc/64: barrier_nospec: Add commandline trigger Thread-Topic: [PATCH RFC rebase 9/9] powerpc/64: barrier_nospec: Add commandline trigger Thread-Index: AQHTvJSv3hggio9YDU6ISyDW5QYSAw== Date: Fri, 23 Mar 2018 15:59:50 +0000 Message-ID: References: <1dcf7403042daddcdb8109f6b852b9bb9d768f89.1521141122.git.msuchanek@suse.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=diana.craciun@nxp.com; x-originating-ip: [86.34.165.90] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;HE1PR0401MB1804;7:DCLFSuULG85RZ+uIWOHOPMkDwINBACKwTZe5VaeN+F3TRn2Mxk1GL3e2/M13T976MBXjQ+/f66ub7TypEfKAWOKy7npgz7Zsm1qadv4mb8n756k5qKmLKZZuah2IbUtSCaAEgH3EYnWUXLBaU0PmqiVIoPAaFYNY6zXBbHSwSDNAPsXsADWJGAPzn0/Vk8yJnEw9vGRbMzP6CQRkMU4XUz9AWGrOQPsxPUYZPsRA8iIhDzqnDS3c1T1jSl/aiMJY x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: 174cb0f9-0746-4f6e-c988-08d590d71c41 x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(48565401081)(5600026)(4604075)(3008032)(4534165)(4627221)(201703031133081)(201702281549075)(2017052603328)(7153060)(7193020);SRVR:HE1PR0401MB1804; x-ms-traffictypediagnostic: HE1PR0401MB1804: x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:; x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(6040522)(2401047)(8121501046)(5005006)(10201501046)(3002001)(93006095)(93001095)(3231221)(944501327)(52105095)(6055026)(6041310)(20161123562045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123564045)(20161123558120)(20161123560045)(6072148)(201708071742011);SRVR:HE1PR0401MB1804;BCL:0;PCL:0;RULEID:;SRVR:HE1PR0401MB1804; x-forefront-prvs: 0620CADDF3 x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(396003)(376002)(39380400002)(366004)(39860400002)(346002)(189003)(199004)(66066001)(2900100001)(3280700002)(97736004)(305945005)(33656002)(68736007)(74316002)(6436002)(55016002)(9686003)(4326008)(446003)(26005)(53546011)(102836004)(6506007)(25786009)(39060400002)(7736002)(186003)(229853002)(14454004)(110136005)(81166006)(8676002)(3660700001)(8936002)(478600001)(76176011)(5250100002)(2906002)(86362001)(81156014)(54906003)(53936002)(7696005)(6246003)(316002)(5660300001)(7416002)(106356001)(99286004)(2501003)(6116002)(105586002)(3846002)(217873001);DIR:OUT;SFP:1101;SCL:1;SRVR:HE1PR0401MB1804;H:HE1PR0401MB2634.eurprd04.prod.outlook.com;FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; x-microsoft-antispam-message-info: O8+OllKFiiDbIhZT+GTJMaJBozzvJZgNUsM1s2w8R4eeV97LfErUWVj/QJoAbwidWxcupoqjfhamyhSv54sPFi7mzvUFSUQ4p2eKlYwTT2H6+PnIuiESY+ZmMtJ0M4ebQiQ+ZN3Xu48YFZuypEr65+p58UNBbuhC3r2mBtcoqYtFaOWYO3vt/yn4fkE9QqlBrOzwp16xG3evhC4ujcjngPDIQVwrVOHDRpxqhgqeXnvHIPHlk2NHeFKxZBOhqtCxnDykpIKojJV/8sWlCBBR+ezgFXYoRy54wwqKdBFKV5A3uLMi23bWVzAVW6eOo5taLqWe3SrVVH24tP/PU5qJzw== spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 174cb0f9-0746-4f6e-c988-08d590d71c41 X-MS-Exchange-CrossTenant-originalarrivaltime: 23 Mar 2018 15:59:50.6735 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-Transport-CrossTenantHeadersStamped: HE1PR0401MB1804 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1595032351746751096?= X-GMAIL-MSGID: =?utf-8?q?1595744762751513450?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 3/15/2018 9:34 PM, Michal Suchanek wrote:=0A= > Add commandline options spectre_v2 and nospectre_v2=0A= >=0A= > These are named same as similar x86 options regardless of actual effect= =0A= > to not require platform-specific configuration.=0A= >=0A= > Supported options:=0A= > nospectre_v2 or spectre_v2=3Doff - speculation barrier not used=0A= > spectre_v2=3Don or spectre_v2=3Dauto - speculation barrier used=0A= =0A= Why the barrier is enabled only for spectre variant 2 mitigations? It=0A= can be used as well for variant 1 mitigations. In fact I am not sure=0A= that the places where it is used fall under spectre 2 at all.=0A= =0A= >=0A= > Changing the settings after boot is not supported and VM migration may=0A= > change requirements so auto is same as on.=0A= >=0A= > Based on s390 implementation=0A= >=0A= > Signed-off-by: Michal Suchanek =0A= > ---=0A= > arch/powerpc/kernel/setup_64.c | 22 ++++++++++++++++++++++=0A= > 1 file changed, 22 insertions(+)=0A= >=0A= > diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_6= 4.c=0A= > index f6678a7b6114..c74e656265df 100644=0A= > --- a/arch/powerpc/kernel/setup_64.c=0A= > +++ b/arch/powerpc/kernel/setup_64.c=0A= > @@ -840,6 +840,28 @@ static int __init handle_no_pti(char *p)=0A= > }=0A= > early_param("nopti", handle_no_pti);=0A= > =0A= > +static int __init nospectre_v2_setup_early(char *str)=0A= > +{=0A= > + no_nospec =3D true;=0A= > + return 0;=0A= > +}=0A= > +early_param("nospectre_v2", nospectre_v2_setup_early);=0A= > +=0A= > +static int __init spectre_v2_setup_early(char *str)=0A= > +{=0A= > + if (str && !strncmp(str, "on", 2))=0A= > + no_nospec =3D false;=0A= > +=0A= > + if (str && !strncmp(str, "off", 3))=0A= > + no_nospec =3D true;=0A= > +=0A= > + if (str && !strncmp(str, "auto", 4))=0A= > + no_nospec =3D false;=0A= > +=0A= > + return 0;=0A= > +}=0A= > +early_param("spectre_v2", spectre_v2_setup_early);=0A= > +=0A= > static void do_nothing(void *unused)=0A= > {=0A= > /*=0A= =0A= Thanks,=0A= =0A= Diana=0A= =0A=