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Commit 032d59e1 authored by Sinan Kaya's avatar Sinan Kaya Committed by Arnd Bergmann
Browse files

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: default avatarSinan Kaya <okaya@codeaurora.org>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 64e2c673

include/asm-generic/io.h

+24 −4
Original line number Diff line number Diff line
@@ -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 */