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Wysocki" , Len Brown , Pavel Machek References: From: Andrew Cooper Message-ID: <5017a6c5-55fa-0767-b1ed-2bd9e2a5efc1@citrix.com> Date: Thu, 14 Jan 2021 22:59:39 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-GB X-ClientProxiedBy: LO4P123CA0496.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:1ab::15) To BYAPR03MB4728.namprd03.prod.outlook.com (2603:10b6:a03:13a::24) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 777ca840-dced-4ff3-139f-08d8b8e01715 X-MS-TrafficTypeDiagnostic: BYAPR03MB3542: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:5236; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: vO4lPCKEArhPccV3p8G3tXTGpWa+v6bq7iHCVXt2t+8r6JNQtukBy9Lm8vtko6Cdu1D1B0mvR8BlQT3CNnfhAS1YlNoZJe4YFKv39NNJc5ylEYUtHpurKs1J31m+dgpXkCIEvfWOJFchAeNER48PxeeQpbCOctzuJW8s9FZzFMvSbatwHSozh+8bFIY+ZMiIhp+5FGmxcb19TJ97tYoFe6twmBZMz5KWAYAk9M4Zw79BQeakB+SpRbvmRqITNFAipMJoCA7cKurc20Fz0cy9a1Qjk0gff1pAfYRli10M//rWMyjbGiwdzpMC/ZysKMP6cg2ueuPABy03lqglTuQXE5CxLFJ5oav+muViRWLDCojEWcLZKZCWsPwtoFQni3C6UCxqWYaREjoKgKquw+qpSR4YVcXV3/nDGMInFObOqWFqaNZ1A/CYZ5bb54pm4IMvOMjz8hD5qX0L7f7nwiaCkFpqkTn7CKt0xlEd6HDFT50= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR03MB4728.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(136003)(39860400002)(366004)(396003)(346002)(376002)(6666004)(2906002)(956004)(2616005)(6486002)(31696002)(66556008)(66946007)(26005)(66476007)(186003)(478600001)(83380400001)(16576012)(7416002)(4326008)(316002)(86362001)(54906003)(5660300002)(31686004)(8936002)(8676002)(53546011)(16526019)(36756003)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?U3J4OTJoRmZSbzBFRzhsWjhlM0IrbEpDY0s1UUhzZ2FYZXRKZ1UvUXlFbW5t?= =?utf-8?B?SE5yR01GWDB2dHJ1M09jd3FDTnFPZFZaZUh1OE9FMTBFbi9JWU1oaWIrL0pj?= =?utf-8?B?bXY5TkhYNVYzUTJFWHprRGR1VWd2bEwzemNBS0NEWmEva3hvejBaWVBJUVpl?= =?utf-8?B?bkc4dFVVRjhjWmhzSlJGakdGQ0VmOFdRSGYxNVk1enM2TC92OHZQRXJIa2ho?= =?utf-8?B?bXhkSUNlQ2kzUTRBY25xL2daUUFMQUpLeXFCWHB6L1ZZcG44ZGQ2UUZmV2ds?= =?utf-8?B?OWl6eklyMHNXRExVZDVIS055Sk9EcmRNSWtrK1lZSmlva2h1QW03SWNmRGMz?= =?utf-8?B?VWhiaEhRQmZZZXZPRGtXbHBtMWpVUEtJZVNYSmh1eGdvUXgvZDYzVk8xeGpr?= =?utf-8?B?Nnl1czFhcGV3Mm5CWVFtUS9FcXYva1ZkeDNtTWZsY1dVM09SKzl3NlpNMWFy?= =?utf-8?B?N3M2TFNoV0hTT2NqWTZoSVFXWTdYWUJ1alZVYzBpa2QzSTRoQTVtenUzVUN3?= =?utf-8?B?clUzdk9iVm1QSEppSWZka2M4LzRrS25jK3pKcXk2M25aWkQydFpDNGhsalhw?= =?utf-8?B?QzB3VEJjYXN1TEFYSU9CMnZtNm52UjdVUFY3SWZBNDFvMzFFd2c0QUwxS3V1?= =?utf-8?B?bEFZWU4vYVZrbnppdG0xNCtLWDFWWG8yWGhlVWRlWGJkMEpTRXhGampZY2Np?= =?utf-8?B?VjlCRWw0WExYMWdjUytxZW1nQ0Z5eHp6azlvWXVpVUdNZ2F1ZzVJWFlEN2JO?= =?utf-8?B?b0dmMTFFTDh2K2JmRm83Ym5MdWZuWDRWR2xkdWsxd0UwNVFCQjJGUmgvOC9p?= =?utf-8?B?UlpScUg2TzlyaXhwWlREd3UyY2VIZDI0Q0dlV29WVEZGRmlQNGlUT3JjNS96?= =?utf-8?B?TmxYLzJSV2tSZFZ0eDdjR3JPdmQyZEE0SkxOUGJnVVYxMGpWbGRwUXNKajd6?= =?utf-8?B?dllieG9jSVU2c25UZ0wxdDdHTHNmNGl3WnM5VVI5clkvNk1NVFprbHpJa3ZC?= =?utf-8?B?RGZYNjAyTmpmaW5vaC9hZjZkMUFwai9rb3pyb2R6cTBkdHcxSTdsb0tUZ3c1?= =?utf-8?B?TVRmaHkwdEYzY0JIaXJmZUhSUlluVXFlYzFCN2pzTUJPanUweFUxNVI4N2tj?= =?utf-8?B?eWgrU1B5Y2xmR2RqU0pBOFpUTlExaFMyZ0lJUTBDMk14VlV1S0VLVnlrblY2?= =?utf-8?B?bzZNZmF0c1RVSndYeDVFRnFoTGloOUFxSHY2U08vZENWUkppd0RMcHJsclo5?= =?utf-8?B?VlpiMUNCQk50UnNudEVNVERSeVdPKzJmL1NQUDNoUEV4a3RmaUkvSnV0VHBa?= =?utf-8?Q?hs5d10+NiqtTV3Uiwzpyk0W2VXD/you7Gg?= X-MS-Exchange-CrossTenant-AuthSource: BYAPR03MB4728.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Jan 2021 22:59:47.1697 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-Network-Message-Id: 777ca840-dced-4ff3-139f-08d8b8e01715 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: TeWiaMYo5hD8BfDOUYE6h964sUSPxgvjk1+NrVq24105XtWKBbwgqrS3/i8JKOLruLzFnuK4KptutqR+WKfJW2nOIVM0ddmjFHv3bGCHBbs= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR03MB3542 X-OriginatorOrg: citrix.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/01/2021 19:40, Josh Poimboeuf wrote: > It's kernel policy to not have (unannotated) indirect jumps because of > Spectre v2. This one's probably harmless, but better safe than sorry. > Convert it to a retpoline. > > Cc: "Rafael J. Wysocki" > Cc: Len Brown > Cc: Pavel Machek > Signed-off-by: Josh Poimboeuf > --- > arch/x86/kernel/acpi/wakeup_64.S | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S > index 5d3a0b8fd379..0b371580e620 100644 > --- a/arch/x86/kernel/acpi/wakeup_64.S > +++ b/arch/x86/kernel/acpi/wakeup_64.S > @@ -7,6 +7,7 @@ > #include > #include > #include > +#include > > # Copyright 2003 Pavel Machek > @@ -39,7 +40,7 @@ SYM_FUNC_START(wakeup_long64) > movq saved_rbp, %rbp > > movq saved_rip, %rax > - jmp *%rax > + JMP_NOSPEC rax > SYM_FUNC_END(wakeup_long64) I suspect this won't work as you intend. wakeup_long64() still executes on the low mappings, not the high mappings, so the `jmp __x86_indirect_thunk_rax` under this JMP_NOSPEC will wander off into the weeds. This is why none of the startup "jmps from weird contexts onto the high mappings" have been retpolined-up. ~Andrew