Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933354AbeAHTfh (ORCPT + 1 other); Mon, 8 Jan 2018 14:35:37 -0500 Received: from smtp-fw-4101.amazon.com ([72.21.198.25]:18630 "EHLO smtp-fw-4101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933109AbeAHTff (ORCPT ); Mon, 8 Jan 2018 14:35:35 -0500 X-Amazon-filename: smime.p7s X-IronPort-AV: E=Sophos;i="5.46,332,1511827200"; d="p7s'?scan'208";a="702393913" Message-ID: <1515440039.7317.41.camel@amazon.co.uk> Subject: Re: [PATCH v2 4/8] x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature To: Peter Zijlstra , Tim Chen , "hongjiu.lu@intel.com" CC: Dave Hansen , Thomas Gleixner , Andy Lutomirski , Linus Torvalds , Greg KH , "Andrea Arcangeli" , Andi Kleen , "Arjan Van De Ven" , In-Reply-To: <20180108174224.GE6176@hirez.programming.kicks-ass.net> References: <20180108124707.GH32035@hirez.programming.kicks-ass.net> <20180108161437.GN32035@hirez.programming.kicks-ass.net> <46157295-e32e-5c9e-0c8b-f91b34f7b02d@linux.intel.com> <20180108174224.GE6176@hirez.programming.kicks-ass.net> Face: 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 Organization: Amazon Content-Type: multipart/signed; micalg=sha-256; protocol="application/x-pkcs7-signature"; boundary="=-x7OgSFbDnL0YiZ2agyTq" Date: Mon, 8 Jan 2018 19:34:00 +0000 X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 MIME-Version: 1.0 From: "Woodhouse, David" X-Evolution-Source: 1481217574.17989.4@uc8d3ff76b9bc5848a9cc Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: --=-x7OgSFbDnL0YiZ2agyTq Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2018-01-08 at 18:42 +0100, Peter Zijlstra wrote: > On Mon, Jan 08, 2018 at 09:28:12AM -0800, Tim Chen wrote: > > On 01/08/2018 08:14 AM, Peter Zijlstra wrote: > > > On Mon, Jan 08, 2018 at 01:47:07PM +0100, Peter Zijlstra wrote: > > >>> a good suggestion, but we encountered some issues with it either > > >>> crashing the kernel at boot or not properly turning on/off. > > >=C2=A0 > > > The below boots, but I lack stuff to test the enabling. > >=C2=A0 > > Peter, > >=C2=A0 > > Thanks.=C2=A0 Will give it a spin.=C2=A0 One other concern is if > > JUMP_LABEL is not configured, this may not work, and > > we may still need fall back to a control variable. >=20 > Urgh yes.. I always forget about that case. Will the retpoline crud be > backported to a GCC old enough to not have asm-goto? If not, we could > make all of this simply require asm-goto. I think HJ said he was planning to backport as far as 4.9. When was asm-goto added? --=-x7OgSFbDnL0YiZ2agyTq Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEE4w ggUuMIIEFqADAgECAhEApEtL31g6H7ROXdOiQnA9RjANBgkqhkiG9w0BAQsFADCBlzELMAkGA1UE BhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgG A1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhl bnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0EwHhcNMTcxMjIxMDAwMDAwWhcNMTgxMjIxMjM1 OTU5WjAiMSAwHgYJKoZIhvcNAQkBFhFkd213QGFtYXpvbi5jby51azCCASIwDQYJKoZIhvcNAQEB BQADggEPADCCAQoCggEBAKdGKgXuwKMg2r+i/4BZZC0ddRxNq3xIKTakie/VCSzoO7P17A36ZzUc VMEYPfqDt/65xoc6Tdih+qkY2pNDppZ1DZ8mVrAX6O2O60ZhmXB60wMoDvXPZInvkMOW4drqnje/ 7/NOypn/XQAY+ln4KT+3tHG3TfryyJFMedqC/r29KJlCeeCxIzdtq2j5mN42tvPVv4+p+Kr77uui GOASNdFJbNdgx7UGF+il6kRGSle17LJZKMgRiLJXYjECwnGwdfLdN5SINWD5IC3yXY8d14Bq6DyD jNts1DFw+SKhW8kVFYRZpv7TE3/42QJKQVL6YWka5T4EJO7AD3gy2ypRsd8CAwEAAaOCAecwggHj MB8GA1UdIwQYMBaAFIKvbIz4xf6WYXzoHz0rcUhexIvAMB0GA1UdDgQWBBT/vhvBExl2wDr8f50u b+0yzFyZRjAOBgNVHQ8BAf8EBAMCBaAwDAYDVR0TAQH/BAIwADAgBgNVHSUEGTAXBggrBgEFBQcD BAYLKwYBBAGyMQEDBQIwEQYJYIZIAYb4QgEBBAQDAgUgMEYGA1UdIAQ/MD0wOwYMKwYBBAGyMQEC AQEBMCswKQYIKwYBBQUHAgEWHWh0dHBzOi8vc2VjdXJlLmNvbW9kby5uZXQvQ1BTMFoGA1UdHwRT MFEwT6BNoEuGSWh0dHA6Ly9jcmwuY29tb2RvY2EuY29tL0NPTU9ET1JTQUNsaWVudEF1dGhlbnRp Y2F0aW9uYW5kU2VjdXJlRW1haWxDQS5jcmwwgYsGCCsGAQUFBwEBBH8wfTBVBggrBgEFBQcwAoZJ aHR0cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRT ZWN1cmVFbWFpbENBLmNydDAkBggrBgEFBQcwAYYYaHR0cDovL29jc3AuY29tb2RvY2EuY29tMBwG A1UdEQQVMBOBEWR3bXdAYW1hem9uLmNvLnVrMA0GCSqGSIb3DQEBCwUAA4IBAQCK2HofespbCaDu udwwfh8GxDpVUnVbZZVWScpZMxfYpXzLot7L6iZrr16oMQ+UOiDDAK6/D3+u2QN8u0lJ6yLKVmvh lGOzDywGsyG2Ohy8Dt5jcEK5sz84OsPtrRH7ahZHLxYPhWlUKOjOPN6sb9h6uMYlXmG/KmAr2rwF exN6Zrwh6YwF7ukuMs175YcNyYRdB8kVYq3WikfbTHOoRbJiu9Unw7LqnvPTfx+xUvD6aN2CKLtr mactWbk98swNgbI18UWjfEpugvAqw09CDLjeq7N1v0SkUkQEDqGSUE+hKFryTNXtZ6zOfl+MQfD8 U7T5oJa34DmWXK9+x7dl+MrqMIIFLjCCBBagAwIBAgIRAKRLS99YOh+0Tl3TokJwPUYwDQYJKoZI hvcNAQELBQAwgZcxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVhdGVyIE1hbmNoZXN0ZXIxEDAO BgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVkMT0wOwYDVQQDEzRDT01P RE8gUlNBIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJlIEVtYWlsIENBMB4XDTE3MTIy MTAwMDAwMFoXDTE4MTIyMTIzNTk1OVowIjEgMB4GCSqGSIb3DQEJARYRZHdtd0BhbWF6b24uY28u dWswggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAwggEKAoIBAQCnRioF7sCjINq/ov+AWWQtHXUcTat8 SCk2pInv1Qks6Duz9ewN+mc1HFTBGD36g7f+ucaHOk3YofqpGNqTQ6aWdQ2fJlawF+jtjutGYZlw etMDKA71z2SJ75DDluHa6p43v+/zTsqZ/10AGPpZ+Ck/t7Rxt0368siRTHnagv69vSiZQnngsSM3 bato+ZjeNrbz1b+Pqfiq++7rohjgEjXRSWzXYMe1BhfopepERkpXteyyWSjIEYiyV2IxAsJxsHXy 3TeUiDVg+SAt8l2PHdeAaug8g4zbbNQxcPkioVvJFRWEWab+0xN/+NkCSkFS+mFpGuU+BCTuwA94 MtsqUbHfAgMBAAGjggHnMIIB4zAfBgNVHSMEGDAWgBSCr2yM+MX+lmF86B89K3FIXsSLwDAdBgNV HQ4EFgQU/74bwRMZdsA6/H+dLm/tMsxcmUYwDgYDVR0PAQH/BAQDAgWgMAwGA1UdEwEB/wQCMAAw IAYDVR0lBBkwFwYIKwYBBQUHAwQGCysGAQQBsjEBAwUCMBEGCWCGSAGG+EIBAQQEAwIFIDBGBgNV HSAEPzA9MDsGDCsGAQQBsjEBAgEBATArMCkGCCsGAQUFBwIBFh1odHRwczovL3NlY3VyZS5jb21v ZG8ubmV0L0NQUzBaBgNVHR8EUzBRME+gTaBLhklodHRwOi8vY3JsLmNvbW9kb2NhLmNvbS9DT01P RE9SU0FDbGllbnRBdXRoZW50aWNhdGlvbmFuZFNlY3VyZUVtYWlsQ0EuY3JsMIGLBggrBgEFBQcB AQR/MH0wVQYIKwYBBQUHMAKGSWh0dHA6Ly9jcnQuY29tb2RvY2EuY29tL0NPTU9ET1JTQUNsaWVu dEF1dGhlbnRpY2F0aW9uYW5kU2VjdXJlRW1haWxDQS5jcnQwJAYIKwYBBQUHMAGGGGh0dHA6Ly9v Y3NwLmNvbW9kb2NhLmNvbTAcBgNVHREEFTATgRFkd213QGFtYXpvbi5jby51azANBgkqhkiG9w0B AQsFAAOCAQEAith6H3rKWwmg7rncMH4fBsQ6VVJ1W2WVVknKWTMX2KV8y6Ley+oma69eqDEPlDog wwCuvw9/rtkDfLtJSesiylZr4ZRjsw8sBrMhtjocvA7eY3BCubM/ODrD7a0R+2oWRy8WD4VpVCjo zjzerG/YerjGJV5hvypgK9q8BXsTema8IemMBe7pLjLNe+WHDcmEXQfJFWKt1opH20xzqEWyYrvV J8Oy6p7z038fsVLw+mjdgii7a5mnLVm5PfLMDYGyNfFFo3xKboLwKsNPQgy43quzdb9EpFJEBA6h klBPoSha8kzV7Weszn5fjEHw/FO0+aCWt+A5llyvfse3ZfjK6jCCBeYwggPOoAMCAQICEGqb4Tg7 /ytrnwHV2binUlYwDQYJKoZIhvcNAQEMBQAwgYUxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVh dGVyIE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1p dGVkMSswKQYDVQQDEyJDT01PRE8gUlNBIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MB4XDTEzMDEx MDAwMDAwMFoXDTI4MDEwOTIzNTk1OVowgZcxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVhdGVy IE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVk MT0wOwYDVQQDEzRDT01PRE8gUlNBIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJlIEVt YWlsIENBMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvrOeV6wodnVAFsc4A5jTxhh2 IVDzJXkLTLWg0X06WD6cpzEup/Y0dtmEatrQPTRI5Or1u6zf+bGBSyD9aH95dDSmeny1nxdlYCeX IoymMv6pQHJGNcIDpFDIMypVpVSRsivlJTRENf+RKwrB6vcfWlP8dSsE3Rfywq09N0ZfxcBa39V0 wsGtkGWC+eQKiz4pBZYKjrc5NOpG9qrxpZxyb4o4yNNwTqzaaPpGRqXB7IMjtf7tTmU2jqPMLxFN e1VXj9XB1rHvbRikw8lBoNoSWY66nJN/VCJv5ym6Q0mdCbDKCMPybTjoNCQuelc0IAaO4nLUXk0B OSxSxt8kCvsUtQIDAQABo4IBPDCCATgwHwYDVR0jBBgwFoAUu69+Aj36pvE8hI6t7jiY7NkyMtQw HQYDVR0OBBYEFIKvbIz4xf6WYXzoHz0rcUhexIvAMA4GA1UdDwEB/wQEAwIBhjASBgNVHRMBAf8E CDAGAQH/AgEAMBEGA1UdIAQKMAgwBgYEVR0gADBMBgNVHR8ERTBDMEGgP6A9hjtodHRwOi8vY3Js LmNvbW9kb2NhLmNvbS9DT01PRE9SU0FDZXJ0aWZpY2F0aW9uQXV0aG9yaXR5LmNybDBxBggrBgEF BQcBAQRlMGMwOwYIKwYBBQUHMAKGL2h0dHA6Ly9jcnQuY29tb2RvY2EuY29tL0NPTU9ET1JTQUFk ZFRydXN0Q0EuY3J0MCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5jb21vZG9jYS5jb20wDQYJKoZI hvcNAQEMBQADggIBAHhcsoEoNE887l9Wzp+XVuyPomsX9vP2SQgG1NgvNc3fQP7TcePo7EIMERoh 42awGGsma65u/ITse2hKZHzT0CBxhuhb6txM1n/y78e/4ZOs0j8CGpfb+SJA3GaBQ+394k+z3ZBy WPQedXLL1OdK8aRINTsjk/H5Ns77zwbjOKkDamxlpZ4TKSDMKVmU/PUWNMKSTvtlenlxBhh7ETrN 543j/Q6qqgCWgWuMAXijnRglp9fyadqGOncjZjaaSOGTTFB+E2pvOUtY+hPebuPtTbq7vODqzCM6 ryEhNhzf+enm0zlpXK7q332nXttNtjv7VFNYG+I31gnMrwfHM5tdhYF/8v5UY5g2xANPECTQdu9v WPoqNSGDt87b3gXb1AiGGaI06vzgkejL580ul+9hz9D0S0U4jkhJiA7EuTecP/CFtR72uYRBcunw wH3fciPjviDDAI9SnC/2aPY8ydehzuZutLbZdRJ5PDEJM/1tyZR2niOYihZ+FCbtf3D9mB12D4ln 9icgc7CwaxpNSCPt8i/GqK2HsOgkL3VYnwtx7cJUmpvVdZ4ognzgXtgtdk3ShrtOS1iAN2ZBXFiR mjVzmehoMof06r1xub+85hFQzVxZx5/bRaTKTlL8YXLI8nAbR9HWdFqzcOoB/hxfEyIQpx9/s81r gzdEZOofSlZHynoSMYIDyjCCA8YCAQEwga0wgZcxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVh dGVyIE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1p dGVkMT0wOwYDVQQDEzRDT01PRE8gUlNBIENsaWVudCBBdXRoZW50aWNhdGlvbiBhbmQgU2VjdXJl IEVtYWlsIENBAhEApEtL31g6H7ROXdOiQnA9RjANBglghkgBZQMEAgEFAKCCAe0wGAYJKoZIhvcN AQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTgwMTA4MTkzMzU5WjAvBgkqhkiG9w0B CQQxIgQgiQgN4t6X/Oxcp9nca2dHHO5lqcL7te7WmQXvhvJ7OTcwgb4GCSsGAQQBgjcQBDGBsDCB rTCBlzELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMH U2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0Eg Q2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEQCkS0vfWDoftE5d06JC cD1GMIHABgsqhkiG9w0BCRACCzGBsKCBrTCBlzELMAkGA1UEBhMCR0IxGzAZBgNVBAgTEkdyZWF0 ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0 ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0aW9uIGFuZCBTZWN1cmUg RW1haWwgQ0ECEQCkS0vfWDoftE5d06JCcD1GMA0GCSqGSIb3DQEBAQUABIIBAHxt3ZXqGxxsNriw n7E8Y9xCnpaMCZeM5nq6mnZIgsb+OKGB+jrQsRAZi8YILNtFhfvGqaDVbTN4eBx/rX4vZIcQhkwy SQIwfm4GIBmC/xLtGlk5xFhyMo89IFt58o4ik2KieaN/dUmdvNixsr4drehkEBgz8D8kzRWpG7k0 Ih4WjMUVorKxIHjcdkNI5xFjirbXFEntnmRLHUGuiq5hGVRBEJNu96xwzmQK+2PpoUZyCJbS1Zpu dgQkolIK/VhxXrqB83Hjpv5KPyDZBazP/vXNVjukd5QfMNNzRTPMsqYP/cZHI9oMe8gLbKzDk/2L UxRPG4ymLD4xNp+4vAtKUFUAAAAAAAA= --=-x7OgSFbDnL0YiZ2agyTq--