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Commit cfab3bdf authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Paul Mackerras
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[POWERPC] Add "memory" clobber to MMIO accessors 



Gcc might re-order MMIO accessors vs. surrounding consistent
memory accesses, which is a "bad thing", and could break drivers.
This fixes it by adding a "memory" clobber to the MMIO accessors,
which should prevent gcc from doing that reordering.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 732bee4c

include/asm-powerpc/io.h

+7 −5
Original line number Diff line number Diff line
@@ -100,7 +100,7 @@ static inline type name(const volatile type __iomem *addr) \ 
{									\

	type ret;							\

	__asm__ __volatile__("sync;" insn ";twi 0,%0,0;isync"		\

 		: "=r" (ret) : "r" (addr), "m" (*addr));		\

		: "=r" (ret) : "r" (addr), "m" (*addr) : "memory");	\

	return ret;							\

}
@@ -108,7 +108,7 @@ static inline type name(const volatile type __iomem *addr) \ 
static inline void name(volatile type __iomem *addr, type val)		\

{									\

	__asm__ __volatile__("sync;" insn				\

 		: "=m" (*addr) : "r" (val), "r" (addr));		\

		: "=m" (*addr) : "r" (val), "r" (addr) : "memory");	\

	IO_SET_SYNC_FLAG();						\

}
@@ -333,7 +333,8 @@ static inline unsigned int name(unsigned int port) \ 
		"	.long	3b,5b\n"		\

		".previous"				\

		: "=&r" (x)				\

		: "r" (port + _IO_BASE));		\

		: "r" (port + _IO_BASE)			\

		: "memory");  				\

	return x;					\

}
@@ -350,7 +351,8 @@ static inline void name(unsigned int val, unsigned int port) \ 
		"	.long	0b,2b\n"		\

		"	.long	1b,2b\n"		\

		".previous"				\

		: : "r" (val), "r" (port + _IO_BASE));	\

		: : "r" (val), "r" (port + _IO_BASE)	\

		: "memory");   	   	   		\

}



__do_in_asm(_rec_inb, "lbzx")