From f8380f976804533df4c6c3d3a0b2cd03c2d262bc Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 15 Dec 2025 17:52:06 +0100 Subject: rseq: Provide static branch for time slice extensions Guard the time slice extension functionality with a static key, which can be disabled on the kernel command line. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251215155708.733429292@linutronix.de --- include/linux/rseq_entry.h | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'include/linux') diff --git a/include/linux/rseq_entry.h b/include/linux/rseq_entry.h index a36b472627de..d0ec4714ffd6 100644 --- a/include/linux/rseq_entry.h +++ b/include/linux/rseq_entry.h @@ -75,6 +75,17 @@ DECLARE_STATIC_KEY_MAYBE(CONFIG_RSEQ_DEBUG_DEFAULT_ENABLE, rseq_debug_enabled); #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); -- cgit v1.2.3