gcc might re-order MMIO accessors vs. surrounding consistent
memory accesses, which is a "bad thing".
Signed-off-by: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
---
include/asm-powerpc/io.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
--- linux-work.orig/include/asm-powerpc/io.h 2008-05-28 09:39:11.000000000
+1000
+++ linux-work/include/asm-powerpc/io.h 2008-05-28 09:40:28.000000000 +1000
@@ -100,7 +100,7 @@ static inline type name(const volatile t
{ \
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; \
}
@@ -108,8 +108,8 @@ static inline type name(const volatile t
static inline void name(volatile type __iomem *addr, type val) \
{ \
__asm__ __volatile__("sync;" insn \
- : "=m" (*addr) : "r" (val), "r" (addr)); \
- IO_SET_SYNC_FLAG(); \
+ : "=m" (*addr) : "r" (val), "r" (addr) : "memory"); \
+ IO_SET_SYNC_FLAG(); \
}
@@ -333,7 +333,8 @@ static inline unsigned int name(unsigned
" .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
" .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")
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