[Minios-devel] [UNIKRAFT PATCH 02/11] include/uk: import write_once and read_once from freebsd

[Yuri Volchkov <yuri.volchkov@xxxxxxxxx>]

commit <910f555845468ecbdd14dbce7bcc584812e084dc>

Signed-off-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
---
 include/uk/arch/atomic.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/include/uk/arch/atomic.h b/include/uk/arch/atomic.h
index ce8f6e5..ccd4417 100644
--- a/include/uk/arch/atomic.h
+++ b/include/uk/arch/atomic.h
@@ -87,4 +87,21 @@ extern "C" {
 }
 #endif
 
+#define        UK_ACCESS_ONCE(x)                       (*(volatile __typeof(x) 
*)&(x))
+
+#define        UK_WRITE_ONCE(x, v) do {        \
+       barrier();                      \
+       UK_ACCESS_ONCE(x) = (v);        \
+       barrier();                      \
+} while (0)
+
+#define        UK_READ_ONCE(x) ({              \
+       __typeof(x) __var = ({          \
+               barrier();              \
+               UK_ACCESS_ONCE(x);      \
+       });                             \
+       barrier();                      \
+       __var;                          \
+})
+
 #endif /* __UKARCH_ATOMIC_H__ */
-- 
2.19.2


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