[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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/io.h b/include/asm-powerpc/io.h
index e0062d7..8918948 100644
--- a/include/asm-powerpc/io.h
+++ b/include/asm-powerpc/io.h
@@ -100,7 +100,7 @@
{ \
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 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 @@
" .long 3b,5b\n" \
".previous" \
: "=&r" (x) \
- : "r" (port + _IO_BASE)); \
+ : "r" (port + _IO_BASE) \
+ : "memory"); \
return x; \
}
@@ -350,7 +351,8 @@
" .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")