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McKenney" , Boqun Feng , Jonathan Corbet , Prakash Sangappa , Madadi Vineeth Reddy , K Prateek Nayak , Steven Rostedt , Sebastian Andrzej Siewior , Arnd Bergmann , linux-arch@vger.kernel.org References: <20250908225709.144709889@linutronix.de> <20250908225752.744169647@linutronix.de> From: Mathieu Desnoyers Content-Language: en-US In-Reply-To: <20250908225752.744169647@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: YQXPR0101CA0048.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c00:14::25) To YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:be::5) Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: YT2PR01MB9175:EE_|YQBPR01MB11226:EE_ X-MS-Office365-Filtering-Correlation-Id: e1a4ab9e-6c8b-4f9c-e279-08ddf149dc2c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014|7053199007; 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McKenney" > Cc: Boqun Feng > --- > include/linux/rseq_entry.h | 11 +++++++++++ > kernel/rseq.c | 17 +++++++++++++++++ > 2 files changed, 28 insertions(+) > > --- a/include/linux/rseq_entry.h > +++ b/include/linux/rseq_entry.h > @@ -77,6 +77,17 @@ DECLARE_STATIC_KEY_MAYBE(CONFIG_RSEQ_DEB > #define rseq_inline __always_inline > #endif > > +#ifdef CONFIG_RSEQ_SLICE_EXTENSION > +DECLARE_STATIC_KEY_TRUE(rseq_slice_extension_key); > + > +static __always_inline bool rseq_slice_extension_enabled(void) > +{ > + return static_branch_likely(&rseq_slice_extension_key); > +} > +#else /* CONFIG_RSEQ_SLICE_EXTENSION */ > +static inline bool rseq_slice_extension_enabled(void) { return false; } > +#endif /* !CONFIG_RSEQ_SLICE_EXTENSION */ > + > bool rseq_debug_update_user_cs(struct task_struct *t, struct pt_regs *regs, unsigned long csaddr); > bool rseq_debug_validate_ids(struct task_struct *t); > > --- a/kernel/rseq.c > +++ b/kernel/rseq.c > @@ -474,3 +474,20 @@ SYSCALL_DEFINE4(rseq, struct rseq __user > > return 0; > } > + > +#ifdef CONFIG_RSEQ_SLICE_EXTENSION > +DEFINE_STATIC_KEY_TRUE(rseq_slice_extension_key); > + > +static int __init rseq_slice_cmdline(char *str) > +{ > + bool on; > + > + if (kstrtobool(str, &on)) > + return -EINVAL; > + > + if (!on) > + static_branch_disable(&rseq_slice_extension_key); > + return 0; as pointed out elsewhere, this should be return 1. Other than that: Reviewed-by: Mathieu Desnoyers > +} > +__setup("rseq_slice_ext=", rseq_slice_cmdline); > +#endif /* CONFIG_RSEQ_SLICE_EXTENSION */ > -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com