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Peter Anvin" , Thomas Gleixner , Ingo Molnar , , , , , , Arnd Bergmann , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , "Jann Horn" , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , "Dave Martin" , Weijiang Yang , Pengfei Xu , Haitao Huang , Rick P Edgecombe References: <20210722205723.9476-1-yu-cheng.yu@intel.com> <20210722205723.9476-5-yu-cheng.yu@intel.com> <3318ca57-7ac3-8296-f9ae-0ae83d5f95dd@kernel.org> From: "Yu, Yu-cheng" Message-ID: <3edaaf51-dbcf-f4fc-de2d-dd72471004f4@intel.com> Date: Tue, 10 Aug 2021 09:07:49 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.12.0 In-Reply-To: <3318ca57-7ac3-8296-f9ae-0ae83d5f95dd@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MWHPR18CA0025.namprd18.prod.outlook.com (2603:10b6:320:31::11) To DM8PR11MB5736.namprd11.prod.outlook.com (2603:10b6:8:11::11) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.0.18] (98.33.34.38) by MWHPR18CA0025.namprd18.prod.outlook.com (2603:10b6:320:31::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4415.14 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?S0h4VzFxS1NTdzZYNXpmYXUrNngyL2RCS0JMOWcxbXJiK3g5c1c1RGdic2FZ?= =?utf-8?B?RDNFeHBMSDJUcXRkbXBoc3hHc1VuMVliRi9lOGNob3Y1Z21nVTN5UEk2b2RI?= =?utf-8?B?TEg4eUVqaTQ4U1RMQ3U3b0tiNHgzQXF6djdZNEswcTZOSnk3K0VPVTJTOUVT?= =?utf-8?B?RkNGdkFvZmVmUnFCcUEwSmhneHRYVndyL0JWNHR1d1Y3MU1oelBQYmVVc1kr?= =?utf-8?B?enRlTUlmcnJScUhFMmc1MDl5RHpaamtQZG15YzhnZE5vRDkvZUZvbFNpYWNH?= =?utf-8?B?eVpqZ0dpbU9iWWR1Wk45QW1sRzBNVUk0TS84VGhCcndPRE1vbjZNRDVJQnpj?= =?utf-8?B?bmhTV0FsdUJoSU9TampUOURkSFcyb1hqS2JocXZlMWdnZUQ4MjdwK21FeHRv?= =?utf-8?B?OGFaK20rZFg0MlhGajJwVDl1d2RsTmwxZTk4R0JZR2Y4MWt0VVFETmNmeFN3?= =?utf-8?B?SEdYbmF3aEZ2N3EzVDlRdWF5OHM2UlgxSVlWR3Jnc0k4bzlxMkRwOCtOamFr?= =?utf-8?B?LzJhaW5zaTN3alowTkEyZmFZWGo5QU1FYVlXbU4wZDQ4blJleTl0SnhmMFBr?= =?utf-8?B?QWFpb04zYUJzRGtJZy9WTU13c3hTM05OQmxSdlBIN1VqdWREbDJqcmFoT2Zl?= =?utf-8?B?WGsySjJjOTBTTnVPRXV6cHhiQkVJSnl5YVAwcTF4OEZDTG9KV3lvZGRIcTlN?= =?utf-8?B?aExUR2E5a1EySDByRTd6WHhsK0tYejhiMmZzR1d0c2pkd25tVnIzakI3RTU0?= =?utf-8?B?b2h3KzVNZDdqN3MrcUF3Q2N2U2lUKzI4enhMYmpCOGJZdWhoajZFWkdQK3k0?= =?utf-8?B?cG9FUmJCckZKZUFSa21NN2J2MWw0dDBSV2VEejl3VmhlbkRZL0xFYmFkaTkv?= =?utf-8?B?S003QUV6UmR6d1FBaS8yQzYxb25rWjVYU25iMktQNjFuc0hFN3lJMGFTWTEr?= =?utf-8?B?cW1LV2hmV0dZK3ozUHpvV3ExZ0ppSit4VGNZSzFnbFQzTTRmME1ZcW5yZHgr?= =?utf-8?B?VWJmcFRodHJsTENlYzdUTDRTZUlCTHR0bkNkOURaRWpLR28vZG9kRTNMQUE0?= =?utf-8?B?eDVDdWNKK3pyenlOa3FOZUErMVRBS0prKzZHcHptMjhWUEVCYmg3bVVmVjAv?= =?utf-8?B?Tm5XQW4vRXJpWFZLYjlFTlVHaFI0WEtvak1VMEtMNUFSN2hjRDZ4MWtubGwr?= =?utf-8?B?Wnh5aTBNRXZTbVFZN3N6MGduR2RTZ2EvMjBRWXh6QWlCVXo4WUVtcWQzeGlQ?= =?utf-8?B?MlREWjB6bFMzZGQzT3hqZHZROGEyYmdETUYyQkYvNGdWWEVVeVhQZVNKdGlw?= =?utf-8?B?U1BkVndWYXZVeFVwUHZXSVlzUGI1TmliQTdpb0JWZmtYOXBldWxXMmVyNVF5?= =?utf-8?B?L0s5Tk43Mk5FbzhhaXcwYXVDSEg3UnVMa1VQNFp0VTljVStDSFBiamIwZUQ3?= =?utf-8?B?Ym8yOGV4UVN2dkVJTjFlcm5PZTd3dFMvZlZxY3VhaDY1dngrSUNaem5hemk2?= =?utf-8?B?OTlsdWQxei9JUUh5c1hEV3I0UFZkSHU5SldRMWRsRDZnYUNUUEpmUnNEREFm?= =?utf-8?B?TW14VW1ncmJad3FFeHRnZ3daNEFEQ2xiQS9GNEVSRlFKdDN4SEh2YnAyMW45?= =?utf-8?B?Q3JxS3MyNDgzSy9QSEZwbHZWaytIVzgvSExqUUxjdVFaSXdWa0NSOVJnbDRi?= =?utf-8?B?SklkUGVxTDI3SXV6S095eXd2b1ZYcGpzS3VqTDg4SFFqSXZpSVROa1RORU5K?= =?utf-8?Q?Og3ECcFZeKl4C7oUw2DLklOvfI+vlXnrKhJ+iDg?= X-MS-Exchange-CrossTenant-Network-Message-Id: dd6cbfd0-1a93-4d86-7bdf-08d95c19034b X-MS-Exchange-CrossTenant-AuthSource: DM8PR11MB5736.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Aug 2021 16:07:55.0554 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: X+7ifWdhhqChoop4B99S84QThBzz6ymDak+Vm3lAFeAJRvOhB7f0Ad5QKLOZ9p0/bjmIWqwauhePD0BmNjyO2A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR11MB1482 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On 8/9/2021 4:04 PM, Andy Lutomirski wrote: > On 7/22/21 1:57 PM, Yu-cheng Yu wrote: >> In a signal, a task's IBT status needs to be saved to the signal frame, and >> later restored in sigreturn. For the purpose, previous versions of the >> series add a new struct to the signal frame. However, a new signal frame >> format (or re-using a reserved space) introduces complex compatibility >> issues. >> >> In the discussion (see link below), Andy Lutomirski proposed using a >> ucontext flag. The approach is clean and eliminates most compatibility >> issues. >> >> However, a legacy IA32 signal frame does not have ucontext and cannot >> support a uc flag. Thus, >> >> - Disable IBT for ia32. >> - In ia32 sigreturn, verify ibt is disabled. > > Acked-by: Andy Lutomirski > Thanks!