diff mbox series

[23/28] x86: mark target address as output in 'insb' asm

Message ID 20161017221650.1902729-4-arnd@arndb.de
State Superseded
Headers show
Series None | expand

Commit Message

Arnd Bergmann Oct. 17, 2016, 10:16 p.m. UTC 
The -Wmaybe-uninitialized warning triggers for one driver using the output
of the 'insb' I/O helper on x86:

drivers/net/wireless/wl3501_cs.c: In function ‘wl3501_mgmt_scan_confirm’:
drivers/net/wireless/wl3501_cs.c:665:9: error: ‘sig.status’ is used uninitialized in this function [-Werror=uninitialized]
drivers/net/wireless/wl3501_cs.c:668:12: error: ‘sig.cap_info’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

Apparently the assember constraints are slightly off here, as marking the
'addr' argument as a memory output seems appropriate here and gets rid
of the warning. For consistency I'm also adding it as input for outsb().

I'm not an x86 person and gcc inline assembly mystifies me all the time,
so please review this carefully and suggest a better way if this is not
how it should be done.

Cc: x86@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 arch/x86/include/asm/io.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.9.0
diff mbox series

Patch

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index de25aad..287234c 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -304,13 +304,13 @@  static inline unsigned type in##bwl##_p(int port)			\
 static inline void outs##bwl(int port, const void *addr, unsigned long count) \
 {									\
 	asm volatile("rep; outs" #bwl					\
-		     : "+S"(addr), "+c"(count) : "d"(port));		\
+		     : "+S"(addr), "+c"(count) : "d"(port), "m" (addr));\
 }									\
 									\
 static inline void ins##bwl(int port, void *addr, unsigned long count)	\
 {									\
 	asm volatile("rep; ins" #bwl					\
-		     : "+D"(addr), "+c"(count) : "d"(port));		\
+		     : "+D"(addr), "+c"(count), "=m" (addr) : "d"(port));\
 }
 
 BUILDIO(b, b, char)