Hi Andrew,
On 08/02/17 19:10, Andrew Cooper wrote:
c/s 11c397c broke the ARM build by introducing a common ACCESS_ONCE() which is
different to the definiton in smmu.c
The SMMU code included a scalar typecheck, which is worth keeping in the
common case, given ACCESS_ONCE()'s restrictions. However, express the
typecheck differently so as to avoid Coverity compliants about unused
s/compliants/complaint/
variables.
OOI, the variable is marked as "__maybe_unused", so why Coverity would
complaint?
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Acked-by: Julien Grall <julien.gr...@arm.com>
Cheers,
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Stefano Stabellini <sstabell...@kernel.org>
CC: Julien Grall <julien.gr...@arm.com>
---
xen/drivers/passthrough/arm/smmu.c | 10 ----------
xen/include/xen/lib.h | 5 ++++-
2 files changed, 4 insertions(+), 11 deletions(-)
diff --git a/xen/drivers/passthrough/arm/smmu.c
b/xen/drivers/passthrough/arm/smmu.c
index cf8b8b8..06c0a45 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -198,16 +198,6 @@ typedef paddr_t phys_addr_t;
#define VA_BITS 0 /* Only used for configuring stage-1
input size */
-/* The macro ACCESS_ONCE start to be replaced in Linux in favor of
- * {READ, WRITE}_ONCE. Rather than introducing in the common code, keep a
- * version here. We will have to drop it when the SMMU code in Linux will
- * switch to {READ, WRITE}_ONCE.
- */
-#define __ACCESS_ONCE(x) ({ \
- __maybe_unused typeof(x) __var = 0; \
- (volatile typeof(x) *)&(x); })
-#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
-
#define MODULE_DEVICE_TABLE(type, name)
#define module_param_named(name, value, type, perm)
#define MODULE_PARM_DESC(_parm, desc)
diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
index 1976e4b..995a85a 100644
--- a/xen/include/xen/lib.h
+++ b/xen/include/xen/lib.h
@@ -56,7 +56,10 @@
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + __must_be_array(x))
-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
+#define __ACCESS_ONCE(x) ({ \
+ (void)(typeof(x))0; /* Scalar typecheck. */ \
+ (volatile typeof(x) *)&(x); })
+#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
#define MASK_EXTR(v, m) (((v) & (m)) / ((m) & -(m)))
#define MASK_INSR(v, m) (((v) * ((m) & -(m))) & (m))
--
Julien Grall
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