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| author | Sinan Kaya <okaya@codeaurora.org> | 2018-04-05 09:09:10 -0400 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2018-04-06 12:01:43 +0200 |
| commit | 032d59e1cde9dd71bb5918e1f6529776623ee86b (patch) | |
| tree | 4d66120ac6a1d2e4e34545fe68c19d1dd48ddde7 /include/asm-generic | |
| parent | 64e2c6738b4d49d69d697b5887f72ad07c206ab3 (diff) | |
| download | linux-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.h | 28 |
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 */ |