Re: [PATCH] rsi: fix integer overflow warning
On Thu, 2017-10-05 at 15:12 +, David Laight wrote: > From: Joe Perches > > Sent: 05 October 2017 13:19 > > On Thu, 2017-10-05 at 14:05 +0200, Arnd Bergmann wrote: > > > gcc produces a harmless warning about a recently introduced > > > signed integer overflow: > > > > > > drivers/net/wireless/rsi/rsi_91x_hal.c: In function > > > 'rsi_prepare_mgmt_desc': > > > include/uapi/linux/swab.h:13:15: error: integer overflow in expression > > > [-Werror=overflow] > > > (((__u16)(x) & (__u16)0x00ffU) << 8) | \ > > >^ > > > include/uapi/linux/swab.h:104:2: note: in expansion of macro > > > '___constant_swab16' > > > ___constant_swab16(x) : \ > > > ^~ > > > include/uapi/linux/byteorder/big_endian.h:34:43: note: in expansion of > > > macro '__swab16' > > > #define __cpu_to_le16(x) ((__force __le16)__swab16((x))) > > > > [] > > > > > The problem is that the 'mask' value is a signed integer that gets > > > turned into a negative number when truncated to 16 bits. Making it > > > an unsigned constant avoids this. > > > > I would expect there are more of these. > > > > Perhaps this define in include/uapi/linux/swab.h: > > > > #define __swab16(x) \ > > (__builtin_constant_p((__u16)(x)) ? \ > > ___constant_swab16(x) : \ > > __fswab16(x)) > > > > should be > > > > #define __swab16(x) \ > > (__builtin_constant_p((__u16)(x)) ? \ > > ___constant_swab16((__u16)(x)) :\ > > __fswab16((__u16)(x))) > > You probably don't want the cast in the call to __fswab16() since > that is likely to generate an explicit and with 0x. > You will likely also get one if the argument is _u16 (not unsigned int). It would just an explicit vs implicit cast as __fswab16 is a static inline with a __u16 argument
RE: [PATCH] rsi: fix integer overflow warning
From: Joe Perches > Sent: 05 October 2017 13:19 > On Thu, 2017-10-05 at 14:05 +0200, Arnd Bergmann wrote: > > gcc produces a harmless warning about a recently introduced > > signed integer overflow: > > > > drivers/net/wireless/rsi/rsi_91x_hal.c: In function 'rsi_prepare_mgmt_desc': > > include/uapi/linux/swab.h:13:15: error: integer overflow in expression > > [-Werror=overflow] > > (((__u16)(x) & (__u16)0x00ffU) << 8) | \ > >^ > > include/uapi/linux/swab.h:104:2: note: in expansion of macro > > '___constant_swab16' > > ___constant_swab16(x) : \ > > ^~ > > include/uapi/linux/byteorder/big_endian.h:34:43: note: in expansion of > > macro '__swab16' > > #define __cpu_to_le16(x) ((__force __le16)__swab16((x))) > > [] > > > The problem is that the 'mask' value is a signed integer that gets > > turned into a negative number when truncated to 16 bits. Making it > > an unsigned constant avoids this. > > I would expect there are more of these. > > Perhaps this define in include/uapi/linux/swab.h: > > #define __swab16(x) \ > (__builtin_constant_p((__u16)(x)) ? \ > ___constant_swab16(x) : \ > __fswab16(x)) > > should be > > #define __swab16(x) \ > (__builtin_constant_p((__u16)(x)) ? \ > ___constant_swab16((__u16)(x)) :\ > __fswab16((__u16)(x))) You probably don't want the cast in the call to __fswab16() since that is likely to generate an explicit and with 0x. You will likely also get one if the argument is _u16 (not unsigned int). David
Re: [PATCH] rsi: fix integer overflow warning
On Thu, 2017-10-05 at 14:05 +0200, Arnd Bergmann wrote: > gcc produces a harmless warning about a recently introduced > signed integer overflow: > > drivers/net/wireless/rsi/rsi_91x_hal.c: In function 'rsi_prepare_mgmt_desc': > include/uapi/linux/swab.h:13:15: error: integer overflow in expression > [-Werror=overflow] > (((__u16)(x) & (__u16)0x00ffU) << 8) | \ >^ > include/uapi/linux/swab.h:104:2: note: in expansion of macro > '___constant_swab16' > ___constant_swab16(x) : \ > ^~ > include/uapi/linux/byteorder/big_endian.h:34:43: note: in expansion of macro > '__swab16' > #define __cpu_to_le16(x) ((__force __le16)__swab16((x))) [] > The problem is that the 'mask' value is a signed integer that gets > turned into a negative number when truncated to 16 bits. Making it > an unsigned constant avoids this. I would expect there are more of these. Perhaps this define in include/uapi/linux/swab.h: #define __swab16(x) \ (__builtin_constant_p((__u16)(x)) ? \ ___constant_swab16(x) : \ __fswab16(x)) should be #define __swab16(x) \ (__builtin_c onstant_p((__u16)(x)) ? \ ___constant_swab16((__u16)(x)) : \ __fswab16((__u16)(x)))
[PATCH] rsi: fix integer overflow warning
gcc produces a harmless warning about a recently introduced
signed integer overflow:
drivers/net/wireless/rsi/rsi_91x_hal.c: In function 'rsi_prepare_mgmt_desc':
include/uapi/linux/swab.h:13:15: error: integer overflow in expression
[-Werror=overflow]
(((__u16)(x) & (__u16)0x00ffU) << 8) | \
^
include/uapi/linux/swab.h:104:2: note: in expansion of macro
'___constant_swab16'
___constant_swab16(x) : \
^~
include/uapi/linux/byteorder/big_endian.h:34:43: note: in expansion of macro
'__swab16'
#define __cpu_to_le16(x) ((__force __le16)__swab16((x)))
^~~~
include/linux/byteorder/generic.h:89:21: note: in expansion of macro
'__cpu_to_le16'
#define cpu_to_le16 __cpu_to_le16
^
drivers/net/wireless/rsi/rsi_91x_hal.c:136:3: note: in expansion of macro
'cpu_to_le16'
cpu_to_le16((tx_params->vap_id << RSI_DESC_VAP_ID_OFST) &
^~~
The problem is that the 'mask' value is a signed integer that gets
turned into a negative number when truncated to 16 bits. Making it
an unsigned constant avoids this.
Fixes: eac4eed3224b ("rsi: tx and rx path enhancements for p2p mode")
Signed-off-by: Arnd Bergmann
---
drivers/net/wireless/rsi/rsi_mgmt.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/rsi/rsi_mgmt.h
b/drivers/net/wireless/rsi/rsi_mgmt.h
index b9d0802c1b0f..e21723013f8d 100644
--- a/drivers/net/wireless/rsi/rsi_mgmt.h
+++ b/drivers/net/wireless/rsi/rsi_mgmt.h
@@ -189,7 +189,7 @@
IEEE80211_WMM_IE_STA_QOSINFO_AC_BE | \
IEEE80211_WMM_IE_STA_QOSINFO_AC_BK)
-#define RSI_DESC_VAP_ID_MASK 0xC000
+#define RSI_DESC_VAP_ID_MASK 0xC000u
#define RSI_DESC_VAP_ID_OFST 14
#define RSI_DATA_DESC_MAC_BBP_INFO BIT(0)
#define RSI_DATA_DESC_NO_ACK_IND BIT(9)
--
2.9.0
