[xlnx:xlnx_rebase_v5.4 1563/1765] drivers/net/ethernet/xilinx/xilinx_axienet_main.c:1962:10: warning: 'regval' may be used uninitialized in this function

Hi Harini,

FYI, the error/warning still remains.

tree:   https://github.com/Xilinx/linux-xlnx xlnx_rebase_v5.4
head:   2f686fa6c0bf7fa168dc45dd7ce1359217212911
commit: d42de16ed2832785de4066fac3883d46ed3f063f [1563/1765] net: xilinx: XXV Ethernet HW timestamp fixes
config: s390-randconfig-s031-20210722 (attached as .config)
compiler: s390-linux-gcc (GCC) 10.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-341-g8af24329-dirty
        # https://github.com/Xilinx/linux-xlnx/commit/d42de16ed2832785de4066fac3883d46ed3f063f
        git remote add xlnx https://github.com/Xilinx/linux-xlnx
        git fetch --no-tags xlnx xlnx_rebase_v5.4
        git checkout d42de16ed2832785de4066fac3883d46ed3f063f
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers/net/ethernet/xilinx/xilinx_axienet_main.c: In function 'axienet_queue_xmit':
   drivers/net/ethernet/xilinx/xilinx_axienet_main.c:1077:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
    1077 |   const struct ethhdr *eth;
         |   ^~~~~
   drivers/net/ethernet/xilinx/xilinx_axienet_main.c: In function 'axienet_set_ts_config':

quoted

drivers/net/ethernet/xilinx/xilinx_axienet_main.c:1962:10: warning: 'regval' may be used uninitialized in this function [-Wmaybe-uninitialized]

    1962 |   regval &= ~XAE_TC_INBAND1588_MASK;
   drivers/net/ethernet/xilinx/xilinx_axienet_main.c:1927:6: note: 'regval' was declared here
    1927 |  u32 regval;
         |      ^~~~~~

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for PTP_1588_CLOCK
   Depends on NET && POSIX_TIMERS
   Selected by
   - XILINX_TSN_PTP && NETDEVICES && ETHERNET && NET_VENDOR_XILINX && XILINX_TSN
   Selected by
   - XILINX_AXI_EMAC_HWTSTAMP && NETDEVICES && ETHERNET && NET_VENDOR_XILINX && XILINX_AXI_EMAC


vim +/regval +1962 drivers/net/ethernet/xilinx/xilinx_axienet_main.c

bbcf6f9bb1bc2063 Saurabh Sengar               2020-02-13  1951  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1952  	/* reserved for future extensions */
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1953  	if (config->flags)
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1954  		return -EINVAL;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1955  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1956  	/* Read the current value in the MAC TX CTRL register */
d42de16ed2832785 Harini Katakam               2020-09-24  1957  	if (lp->axienet_config->mactype != XAXIENET_10G_25G)
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1958  		regval = axienet_ior(lp, XAE_TC_OFFSET);
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1959  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1960  	switch (config->tx_type) {
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1961  	case HWTSTAMP_TX_OFF:
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24 @1962  		regval &= ~XAE_TC_INBAND1588_MASK;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1963  		break;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1964  	case HWTSTAMP_TX_ON:
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1965  		config->tx_type = HWTSTAMP_TX_ON;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1966  		regval |= XAE_TC_INBAND1588_MASK;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1967  		break;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1968  	case HWTSTAMP_TX_ONESTEP_SYNC:
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1969  		config->tx_type = HWTSTAMP_TX_ONESTEP_SYNC;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1970  		regval |= XAE_TC_INBAND1588_MASK;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1971  		break;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1972  	default:
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1973  		return -ERANGE;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1974  	}
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1975  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1976  	if (lp->axienet_config->mactype != XAXIENET_10G_25G)
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1977  		axienet_iow(lp, XAE_TC_OFFSET, regval);
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1978  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1979  	/* Read the current value in the MAC RX RCW1 register */
d42de16ed2832785 Harini Katakam               2020-09-24  1980  	if (lp->axienet_config->mactype != XAXIENET_10G_25G)
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1981  		regval = axienet_ior(lp, XAE_RCW1_OFFSET);
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1982  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1983  	/* On RX always timestamp everything */
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1984  	switch (config->rx_filter) {
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1985  	case HWTSTAMP_FILTER_NONE:
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1986  		regval &= ~XAE_RCW1_INBAND1588_MASK;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1987  		break;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1988  	default:
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1989  		config->rx_filter = HWTSTAMP_FILTER_ALL;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1990  		regval |= XAE_RCW1_INBAND1588_MASK;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1991  	}
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1992  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1993  	if (lp->axienet_config->mactype != XAXIENET_10G_25G)
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1994  		axienet_iow(lp, XAE_RCW1_OFFSET, regval);
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1995  
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1996  	return 0;
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1997  }
7aee9da192ba5721 Appana Durga Kedareswara Rao 2020-01-24  1998  

:::::: The code at line 1962 was first introduced by commit
:::::: 7aee9da192ba57210897a418ada793ac5b15a851 net: axienet: Add support for 1588

:::::: TO: Appana Durga Kedareswara Rao [off-list ref]
:::::: CC: Michal Simek [off-list ref]

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org