From: Benjamin Herrenschmidt Date: Wed, 28 May 2008 00:18:17 +0000 (+1000) Subject: [POWERPC] Add "memory" clobber to MMIO accessors X-Git-Tag: v2.6.26-rc5~27^2~2 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cfab3bdf8292edec19492c89520b1ad11279a648;p=linux-2.6 [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 Signed-off-by: Paul Mackerras --- diff --git a/include/asm-powerpc/io.h b/include/asm-powerpc/io.h index e0062d73db..89189488e2 100644 --- a/include/asm-powerpc/io.h +++ b/include/asm-powerpc/io.h @@ -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; \ } @@ -108,8 +108,8 @@ 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)); \ - 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 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")