[prev in list] [next in list] [prev in thread] [next in thread]
List: linux-alpha
Subject: [PATCH 03/18] asm/rwonce: Allow __READ_ONCE to be overridden by the architecture
From: Will Deacon <will () kernel ! org>
Date: 2020-06-30 17:37:19
Message-ID: 20200630173734.14057-4-will () kernel ! org
[Download RAW message or body]
The meat and potatoes of READ_ONCE() is defined by the __READ_ONCE()
macro, which uses a volatile casts in an attempt to avoid tearing of
byte, halfword, word and double-word accesses. Allow this to be
overridden by the architecture code in the case that things like memory
barriers are also required.
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
include/asm-generic/rwonce.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/asm-generic/rwonce.h b/include/asm-generic/rwonce.h
index 92cc2f223cb3..f9dfa88fc04d 100644
--- a/include/asm-generic/rwonce.h
+++ b/include/asm-generic/rwonce.h
@@ -33,7 +33,9 @@
* atomicity or dependency ordering guarantees. Note that this may result
* in tears!
*/
+#ifndef __READ_ONCE
#define __READ_ONCE(x) (*(const volatile __unqual_scalar_typeof(x) *)&(x))
+#endif
#define __READ_ONCE_SCALAR(x) \
({ \
--
2.27.0.212.ge8ba1cc988-goog
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic