rseq: Provide tracepoint wrappers for inline code

Provide tracepoint wrappers for the upcoming RSEQ exit to user space inline
fast path, so that the header can be safely included by code which defines
actual trace points.

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/20251027084306.967114316@linutronix.de

diff --git a/include/linux/rseq_entry.h b/include/linux/rseq_entry.h
index ce30e87ce1f573c9a0d05bed757292012525b537..5be507a127eb4594b6d600f927acf3883a34afd4 100644 (file)
--- a/include/linux/rseq_entry.h
+++ b/include/linux/rseq_entry.h
@@ -5,6 +5,34 @@
 #ifdef CONFIG_RSEQ
 #include <linux/rseq.h>
 
+#include <linux/tracepoint-defs.h>
+
+#ifdef CONFIG_TRACEPOINTS
+DECLARE_TRACEPOINT(rseq_update);
+DECLARE_TRACEPOINT(rseq_ip_fixup);
+void __rseq_trace_update(struct task_struct *t);
+void __rseq_trace_ip_fixup(unsigned long ip, unsigned long start_ip,
+                          unsigned long offset, unsigned long abort_ip);
+
+static inline void rseq_trace_update(struct task_struct *t, struct rseq_ids *ids)
+{
+       if (tracepoint_enabled(rseq_update) && ids)
+               __rseq_trace_update(t);
+}
+
+static inline void rseq_trace_ip_fixup(unsigned long ip, unsigned long start_ip,
+                                      unsigned long offset, unsigned long abort_ip)
+{
+       if (tracepoint_enabled(rseq_ip_fixup))
+               __rseq_trace_ip_fixup(ip, start_ip, offset, abort_ip);
+}
+
+#else /* CONFIG_TRACEPOINT */
+static inline void rseq_trace_update(struct task_struct *t, struct rseq_ids *ids) { }
+static inline void rseq_trace_ip_fixup(unsigned long ip, unsigned long start_ip,
+                                      unsigned long offset, unsigned long abort_ip) { }
+#endif /* !CONFIG_TRACEPOINT */
+
 static __always_inline void rseq_note_user_irq_entry(void)
 {
        if (IS_ENABLED(CONFIG_GENERIC_IRQ_ENTRY))

diff --git a/kernel/rseq.c b/kernel/rseq.c
index ad1e7cecd527df6bfa5f99f49c61969ab7b5cbb9..f49d3118c3e003550a352d3b043e845052c7e79c 100644 (file)
--- a/kernel/rseq.c
+++ b/kernel/rseq.c
@@ -70,7 +70,7 @@
 #include <linux/sched.h>
 #include <linux/uaccess.h>
 #include <linux/syscalls.h>
-#include <linux/rseq.h>
+#include <linux/rseq_entry.h>
 #include <linux/types.h>
 #include <linux/ratelimit.h>
 #include <asm/ptrace.h>
@@ -91,6 +91,23 @@
                                  RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL | \
                                  RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE)
 
+#ifdef CONFIG_TRACEPOINTS
+/*
+ * Out of line, so the actual update functions can be in a header to be
+ * inlined into the exit to user code.
+ */
+void __rseq_trace_update(struct task_struct *t)
+{
+       trace_rseq_update(t);
+}
+
+void __rseq_trace_ip_fixup(unsigned long ip, unsigned long start_ip,
+                          unsigned long offset, unsigned long abort_ip)
+{
+       trace_rseq_ip_fixup(ip, start_ip, offset, abort_ip);
+}
+#endif /* CONFIG_TRACEPOINTS */
+
 #ifdef CONFIG_DEBUG_RSEQ
 static struct rseq *rseq_kernel_fields(struct task_struct *t)
 {