From 9c37cb6e80b8fcdddc1236ba42ffd438f511192b Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 27 Oct 2025 09:44:55 +0100
Subject: rseq: Provide static branch for runtime debugging

Config based debug is rarely turned on and is not available easily when
things go wrong.

Provide a static branch to allow permanent integration of debug mechanisms
along with the usual toggles in Kconfig, command line and debugfs.

Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.089270547@linutronix.de
---
 include/linux/rseq_entry.h | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'include/linux')

diff --git a/include/linux/rseq_entry.h b/include/linux/rseq_entry.h
index ff9080b89be3..ed8e5f89499b 100644
--- a/include/linux/rseq_entry.h
+++ b/include/linux/rseq_entry.h
@@ -34,6 +34,7 @@ DECLARE_PER_CPU(struct rseq_stats, rseq_stats);
 #endif /* !CONFIG_RSEQ_STATS */
 
 #ifdef CONFIG_RSEQ
+#include <linux/jump_label.h>
 #include <linux/rseq.h>
 
 #include <linux/tracepoint-defs.h>
@@ -64,6 +65,8 @@ static inline void rseq_trace_ip_fixup(unsigned long ip, unsigned long start_ip,
 				       unsigned long offset, unsigned long abort_ip) { }
 #endif /* !CONFIG_TRACEPOINT */
 
+DECLARE_STATIC_KEY_MAYBE(CONFIG_RSEQ_DEBUG_DEFAULT_ENABLE, rseq_debug_enabled);
+
 static __always_inline void rseq_note_user_irq_entry(void)
 {
 	if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY))
-- 
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