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authorSinan Kaya <okaya@codeaurora.org>2018-04-05 09:09:10 -0400
committerArnd Bergmann <arnd@arndb.de>2018-04-06 12:01:43 +0200
commit032d59e1cde9dd71bb5918e1f6529776623ee86b (patch)
tree4d66120ac6a1d2e4e34545fe68c19d1dd48ddde7 /include/asm-generic
parent64e2c6738b4d49d69d697b5887f72ad07c206ab3 (diff)
downloadlinux-032d59e1cde9dd71bb5918e1f6529776623ee86b.tar.bz2
io: define stronger ordering for the default readX() implementation
The default implementation of mapping readX() to __raw_readX() is wrong. readX() has stronger ordering semantics. Compiler is allowed to reorder __raw_readX() against the memory accesses following register read. Use the previously defined __io_ar() and __io_br() macros to harden code generation according to architecture support. Signed-off-by: Sinan Kaya <okaya@codeaurora.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/io.h28
1 files changed, 24 insertions, 4 deletions
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 570433b34180..d27e8af9dd5a 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -154,7 +154,12 @@ static inline void __raw_writeq(u64 value, volatile void __iomem *addr)
#define readb readb
static inline u8 readb(const volatile void __iomem *addr)
{
- return __raw_readb(addr);
+ u8 val;
+
+ __io_br();
+ val = __raw_readb(addr);
+ __io_ar();
+ return val;
}
#endif
@@ -162,7 +167,12 @@ static inline u8 readb(const volatile void __iomem *addr)
#define readw readw
static inline u16 readw(const volatile void __iomem *addr)
{
- return __le16_to_cpu(__raw_readw(addr));
+ u16 val;
+
+ __io_br();
+ val = __le16_to_cpu(__raw_readw(addr));
+ __io_ar();
+ return val;
}
#endif
@@ -170,7 +180,12 @@ static inline u16 readw(const volatile void __iomem *addr)
#define readl readl
static inline u32 readl(const volatile void __iomem *addr)
{
- return __le32_to_cpu(__raw_readl(addr));
+ u32 val;
+
+ __io_br();
+ val = __le32_to_cpu(__raw_readl(addr));
+ __io_ar();
+ return val;
}
#endif
@@ -179,7 +194,12 @@ static inline u32 readl(const volatile void __iomem *addr)
#define readq readq
static inline u64 readq(const volatile void __iomem *addr)
{
- return __le64_to_cpu(__raw_readq(addr));
+ u64 val;
+
+ __io_br();
+ val = __le64_to_cpu(__raw_readq(addr));
+ __io_ar();
+ return val;
}
#endif
#endif /* CONFIG_64BIT */