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client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by BL6PEPF00022571.mail.protection.outlook.com (10.167.249.39) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8466.11 via Frontend Transport; Thu, 20 Feb 2025 10:56:45 +0000 Received: from [10.252.205.52] (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Thu, 20 Feb 2025 04:56:38 -0600 Message-ID: <5b4aa0d0-62b9-484d-a95f-316f5defbc28@amd.com> Date: Thu, 20 Feb 2025 16:26:15 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 01/22] kernel/entry/common: Move syscall_enter_from_user_mode_work() out of header To: Peter Zijlstra CC: Ingo Molnar , Juri Lelli , Vincent Guittot , Valentin Schneider , Ben Segall , Thomas Gleixner , Andy Lutomirski , , Dietmar Eggemann , Steven Rostedt , Mel Gorman , "Sebastian Andrzej Siewior" , Clark Williams , , Tejun Heo , Frederic Weisbecker , Barret Rhoden , Petr Mladek , Josh Don , Qais Yousef , "Paul E. McKenney" , David Vernet , "Gautham R. Shenoy" , Swapnil Sapkal References: <20250220093257.9380-1-kprateek.nayak@amd.com> <20250220093257.9380-2-kprateek.nayak@amd.com> <20250220104355.GI34567@noisy.programming.kicks-ass.net> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20250220104355.GI34567@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL6PEPF00022571:EE_|DM6PR12MB4388:EE_ X-MS-Office365-Filtering-Correlation-Id: de99e257-aec9-4ebd-bc94-08dd519d4477 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|7416014|376014|82310400026|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?NTRNcm5PMUthanB1SHFvQ2R2dnJzWVVmSUNhbU5CcmsxMzAwZXdUM0ZGTUFj?= =?utf-8?B?aDBEZUpXZlI1aFpMNDVxT3FsNldXZkxyWnRYL0c1NllQN0plSkE3M0xpcjV0?= =?utf-8?B?OU51TWY3WDlhVVNkTG16MU9GQjUxaVlEWmZuN1N3dnlKVWR0eTFTa3B1NGRa?= =?utf-8?B?eGw0UTZXQjhDdC83dU4wb0Q5aTI4VzRsNmFNM3lybExFT3BzdUo4MlZEd0tv?= =?utf-8?B?bnF6cFVhcnRSRXBha0VLUGU2a09NNFRlY1JYZzlqdHRtUTkrZkNVRldwVlJk?= =?utf-8?B?ZlJxRzhYWWl3MW1haVc3aTc1ak9PR25Ud0EzQU5zenFHRmxMVWRQMDJGMDFQ?= =?utf-8?B?dHRON2R1eExVTXZsNVZxTCtGV1haaTRSSG5FYXBtNmx1MjBsaGNQSGgyaHRk?= =?utf-8?B?Sm94UkZER2ZodkYrRUpSb1ZwUVNZa0lIc2JUa29ycTZvZ05jRXQ5QlZ6Qzgz?= =?utf-8?B?Y3pnUkFYZTc0RnBrM0o3NHRkZTNBaitzT0hpSzY4b1ZvaElRZS96N2hFNHpj?= =?utf-8?B?bWN1eHdOOFo2SjJLRkgxWHYzZmxaWHVNTE83blZaS3ZoR0JTVHBXN2I1anVL?= =?utf-8?B?b21VTC94cVdGWDRNekVUWFZzS3pGVTIrSHZ0ZXJHeWZqL0JhODhqeUNpRTI1?= =?utf-8?B?RlR2UFBGS0ZiRklQdUxsVitYOGhFR0E1aGpRSzh4V3h2WER1cFB3M1RubTYr?= =?utf-8?B?TWlPM0NleGV1c1pseTJJOXorSCttNHFVakFTby9MZFZzOFBZU21uVS8reDRX?= =?utf-8?B?cWNIL0xkOUFETEJUQTVqMDFvcThVcVc2MjVLSkVha0luN2ducnVaZjZvV3A3?= =?utf-8?B?bzJVc2ZIVjN4YkdqKzhjZWpPbXVtT1d5Ulo2cmNkZVp6NkRnakl6RkdaRjdR?= =?utf-8?B?VHYzOGhZMUM1dEJqTG8rZU1rOFBjcEQ1d3lYcUZJcFdEb2lHU0ZBNG8xSjcv?= =?utf-8?B?RTBKMXJ5KytybmVoaDJ3bmJETUMyWHJoNEN0MUVaYm9nM0RuOHB1VzJEYUxW?= =?utf-8?B?ekRCQnJQOXJ3N2RjOWkzMkd4dXNRKzhnbGxRMzBHTDNDZXVLblRzMkF3cHZm?= =?utf-8?B?Z3dGK3JsSTJHa0J5Tk9yRXVISER5M1g3bzB2cEQwcnIxaGNUZi9nYmZtb05W?= =?utf-8?B?bkMzVkJMTk94dHFibDlaL3VpUGZQTU5uTldNNU9weDl2S1VSVGplNDh1Tjkv?= =?utf-8?B?dkxYdGo0RjFrOUhIS0x3ZXhxbDNROG8zM2FyUkhJMUVvTU5iSUkzWEdtM21I?= =?utf-8?B?aXhiZktTUDlJanhWakZCVEZyTXg3dC9VRnBGTitpWmFnaGVsSEpTUFlDZHl3?= =?utf-8?B?NjNpUWpZZUdxMTZmcUN4SjVPVHpITUxKZ2VDSG1lTkdRR1RiMm10MFVEQVgy?= =?utf-8?B?UUdwN2tqRVoxRkZ1OFdiUWsxdlBhZjN1bHNJYmtkTUROdEkzYXN5NG1VQ2kz?= =?utf-8?B?YVBWeXZub3BBQVJjcStVTVZnUFRMbldQeDBrZGN5SDY2SmV4UjZUUHNjdFRj?= =?utf-8?B?N0lxdnhQQTNxQ01MNkQwVFI4eXNxZzlCa1E3bHBNUkdUUGVKaUVCL0wzZVBV?= =?utf-8?B?eW5NRE1QbXZOY09abjlhbHZNZzQvNEZJOEFYamdhdU5aMitESTYwcGs1MG1Q?= =?utf-8?B?cEVpaUNTOC9LUmx6MVRxaGpYVUc1WDlkemNyZWhJaDBmQ0xNWXphVGE5aHdk?= =?utf-8?B?UWlPVWdTcWdWcW5JNm40dFl0d1d0RlFvUStDNG9nL1c0ZWUybS9EYzBNUGUx?= =?utf-8?B?ZUI3S0pGam4wMGZFeGJzKzhOU0FHYVZKQlZFc3p5QWpSejdSVFRuUTZuOEVM?= =?utf-8?B?dmpUYTQraElmZ2Z3UUVOOGFOQ0dJK3REbUkvaCtPa3UvbGZmaTZRNGdkWm9J?= =?utf-8?B?aWw0UzYrVDNKRlJ2ZmZTeVErTUhxRDJtV2szWmVuVTBBN2lwbDZTbmtLWWpJ?= =?utf-8?B?QnlKa0dJOVZIZUxzTHF4U1pPb3QrMnU2eEZ3Ky9iRHNPU2NxRGd1TU44cG9Z?= =?utf-8?Q?tPYRkg7JmpeyJCNaTTN7z4Ni2MC+c4=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(36860700013)(7416014)(376014)(82310400026)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Feb 2025 10:56:45.6422 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: de99e257-aec9-4ebd-bc94-08dd519d4477 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BL6PEPF00022571.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4388 Hello Peter, Thank you for taking a look. On 2/20/2025 4:13 PM, Peter Zijlstra wrote: > On Thu, Feb 20, 2025 at 09:32:36AM +0000, K Prateek Nayak wrote: >> Retain the prototype of syscall_enter_from_user_mode_work() in >> linux/entry-common.h and move the function definition to >> kernel/entry/common.c in preparation to notify the scheduler of task >> entering and exiting kernel mode for syscall. The two architectures that >> use it directly (x86, s390) and the four that call it via >> syscall_enter_from_user_mode() (x86, riscv, loongarch, s390) end up >> selecting GENERIC_ENTRY, hence, no functional changes are intended. >> >> [..snip..] >> >> @@ -79,6 +79,16 @@ noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs) >> instrumentation_end(); >> } >> >> +__always_inline long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall) >> +{ >> + unsigned long work = READ_ONCE(current_thread_info()->syscall_work); >> + >> + if (work & SYSCALL_WORK_ENTER) >> + syscall = syscall_trace_enter(regs, syscall, work); >> + >> + return syscall; >> +} >> + >> /* Workaround to allow gradual conversion of architecture code */ >> void __weak arch_do_signal_or_restart(struct pt_regs *regs) { } > > This breaks s390. While you retain an external linkage, the function > looses the noinstr tag that's needed for correctness. > > Also, extern __always_inline is flaky as heck. Please don't do this. Noted! I'll try to find another way around this. -- Thanks and Regards, Prateek