Clang staic checker warning: drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c:184:49: The result of the left shift is undefined due to shifting by '32', which is greater or equal to the width of type 'u32'. [core.UndefinedBinaryOperatorResult] If the value of the right operand is negative or is greater than or equal to the width of the promoted left operand, the behavior is undefined.[1][2] For example, when using different gcc's compilation optimizaation options (-O0 or -O2), the result of '(u32)data << 32' is different. One is 0, the other is old value of data. Adding an u64 cast to fix this problem. [1]:https://stackoverflow.com/questions/11270492/what-does-the-c- standard-say-about-bitshifting-more-bits-than-the-width-of-type [2]:https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf Fixes: 21e4b0726dc6 ("rtlwifi: rtl8821ae: Move driver from staging to regular tree") Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx> --- drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c index 6df270e29e66..89713e0587b5 100644 --- a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c @@ -106,7 +106,7 @@ u32 rtl8821ae_phy_query_bb_reg(struct ieee80211_hw *hw, u32 regaddr, regaddr, bitmask); originalvalue = rtl_read_dword(rtlpriv, regaddr); bitshift = _rtl8821ae_phy_calculate_bit_shift(bitmask); - returnvalue = (originalvalue & bitmask) >> bitshift; + returnvalue = (u64)(originalvalue & bitmask) >> bitshift; rtl_dbg(rtlpriv, COMP_RF, DBG_TRACE, "BBR MASK=0x%x Addr[0x%x]=0x%x\n", @@ -128,7 +128,7 @@ void rtl8821ae_phy_set_bb_reg(struct ieee80211_hw *hw, originalvalue = rtl_read_dword(rtlpriv, regaddr); bitshift = _rtl8821ae_phy_calculate_bit_shift(bitmask); data = ((originalvalue & (~bitmask)) | - ((data << bitshift) & bitmask)); + (((u64)data << bitshift) & bitmask)); } rtl_write_dword(rtlpriv, regaddr, data); @@ -153,7 +153,7 @@ u32 rtl8821ae_phy_query_rf_reg(struct ieee80211_hw *hw, original_value = _rtl8821ae_phy_rf_serial_read(hw, rfpath, regaddr); bitshift = _rtl8821ae_phy_calculate_bit_shift(bitmask); - readback_value = (original_value & bitmask) >> bitshift; + readback_value = (u64)(original_value & bitmask) >> bitshift; spin_unlock(&rtlpriv->locks.rf_lock); @@ -181,7 +181,7 @@ void rtl8821ae_phy_set_rf_reg(struct ieee80211_hw *hw, original_value = _rtl8821ae_phy_rf_serial_read(hw, rfpath, regaddr); bitshift = _rtl8821ae_phy_calculate_bit_shift(bitmask); - data = ((original_value & (~bitmask)) | (data << bitshift)); + data = ((original_value & (~bitmask)) | ((u64)data << bitshift)); } _rtl8821ae_phy_rf_serial_write(hw, rfpath, regaddr, data); -- 2.30.2
