@@ -310,6 +310,26 @@ unsigned long read_word_at_a_time(const void *addr)
__u.__val; \
})
+#include <linux/kcsan.h>
+
+/*
+ * data_race: macro to document that accesses in an expression may conflict with
+ * other concurrent accesses resulting in data races, but the resulting
+ * behaviour is deemed safe regardless.
+ *
+ * This macro *does not* affect normal code generation, but is a hint to tooling
+ * that data races here should be ignored.
+ */
+#define data_race(expr) \
+ ({ \
+ typeof(({ expr; })) __val; \
+ kcsan_nestable_atomic_begin(); \
+ __val = ({ expr; }); \
+ kcsan_nestable_atomic_end(); \
+ __val; \
+ })
+#else
+
#endif /* __KERNEL__ */
/*
This introduces the data_race(expr) macro, which can be used to annotate expressions for purposes of (1) documenting, and (2) giving tooling such as KCSAN information about which data races are deemed "safe". More context: http://lkml.kernel.org/r/CAHk-=wg5CkOEF8DTez1Qu0XTEFw_oHhxN98bDnFqbY7HL5AB2g@mail.gmail.com Signed-off-by: Marco Elver <elver@google.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Eric Dumazet <edumazet@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@kernel.org> --- v4: * Introduce this patch to KCSAN series. --- include/linux/compiler.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)