tree:   git://git.armlinux.org.uk/~rmk/linux-arm.git cex7
head:   c333ba58ac979daa84d7ea59b7d4a04c15cce2e7
commit: d45ed9abba2dce5bb6faeb3474264ba64ef2d610 [96/112] ahci: qoriq: workaround for errata A-379364 on lx2160a
config: sparc64-randconfig-a001-20200303 (attached as .config)
compiler: sparc64-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout d45ed9abba2dce5bb6faeb3474264ba64ef2d610
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=sparc64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

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 >>):

   In file included from arch/sparc/include/asm/io.h:5:0,
                    from include/linux/io.h:13,
                    from include/linux/of_address.h:7,
                    from drivers//ata/ahci_qoriq.c:14:
   drivers//ata/ahci_qoriq.c: In function 'ahci_qoriq_hardreset':
>> arch/sparc/include/asm/io_64.h:179:2: warning: 'px_is' may be used uninitialized in this function [-Wmaybe-uninitialized]
     __asm__ __volatile__("stwa\t%r0, [%1] %2\t/* pci_writel */"
     ^~~~~~~
   drivers//ata/ahci_qoriq.c:229:14: note: 'px_is' was declared here
     u32 px_cmd, px_is, px_val;
                 ^~~~~
   In file included from arch/sparc/include/asm/io.h:5:0,
                    from include/linux/io.h:13,
                    from include/linux/of_address.h:7,
                    from drivers//ata/ahci_qoriq.c:14:
>> arch/sparc/include/asm/io_64.h:179:2: warning: 'px_cmd' may be used uninitialized in this function [-Wmaybe-uninitialized]
     __asm__ __volatile__("stwa\t%r0, [%1] %2\t/* pci_writel */"
     ^~~~~~~
   drivers//ata/ahci_qoriq.c:229:6: note: 'px_cmd' was declared here
     u32 px_cmd, px_is, px_val;
         ^~~~~~
--
   In file included from arch/sparc/include/asm/io.h:5:0,
                    from include/linux/io.h:13,
                    from include/linux/of_address.h:7,
                    from drivers/ata/ahci_qoriq.c:14:
   drivers/ata/ahci_qoriq.c: In function 'ahci_qoriq_hardreset':
>> arch/sparc/include/asm/io_64.h:179:2: warning: 'px_is' may be used uninitialized in this function [-Wmaybe-uninitialized]
     __asm__ __volatile__("stwa\t%r0, [%1] %2\t/* pci_writel */"
     ^~~~~~~
   drivers/ata/ahci_qoriq.c:229:14: note: 'px_is' was declared here
     u32 px_cmd, px_is, px_val;
                 ^~~~~
   In file included from arch/sparc/include/asm/io.h:5:0,
                    from include/linux/io.h:13,
                    from include/linux/of_address.h:7,
                    from drivers/ata/ahci_qoriq.c:14:
>> arch/sparc/include/asm/io_64.h:179:2: warning: 'px_cmd' may be used uninitialized in this function [-Wmaybe-uninitialized]
     __asm__ __volatile__("stwa\t%r0, [%1] %2\t/* pci_writel */"
     ^~~~~~~
   drivers/ata/ahci_qoriq.c:229:6: note: 'px_cmd' was declared here
     u32 px_cmd, px_is, px_val;
         ^~~~~~

vim +/px_is +179 arch/sparc/include/asm/io_64.h

f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17  174  
79294d7eff89f6 arch/sparc/include/asm/io_64.h Sam Ravnborg  2014-07-20  175  #define writel writel
7c3969c3a4f359 arch/sparc/include/asm/io_64.h Arnd Bergmann 2014-11-19  176  #define writel_relaxed writel
79294d7eff89f6 arch/sparc/include/asm/io_64.h Sam Ravnborg  2014-07-20  177  static inline void writel(u32 l, volatile void __iomem *addr)
f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17  178  {
f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17 @179  	__asm__ __volatile__("stwa\t%r0, [%1] %2\t/* pci_writel */"
f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17  180  			     : /* no outputs */
f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17  181  			     : "Jr" (l), "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E_L)
f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17  182  			     : "memory");
f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17  183  }
f5e706ad886b6a include/asm-sparc/io_64.h      Sam Ravnborg  2008-07-17  184  

:::::: The code at line 179 was first introduced by commit
:::::: f5e706ad886b6a5eb59637830110b09ccebf01c5 sparc: join the remaining header files

:::::: TO: Sam Ravnborg <sam@ravnborg.org>
:::::: CC: David S. Miller <davem@davemloft.net>

---
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