Hi Nicholas,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on powerpc/next]
[also build test WARNING on linus/master scottwood/next v5.7-rc3]
[cannot apply to next-20200501]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Nicholas-Piggin/OPAL-V4/20200502-195816
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=powerpc 

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

All warnings (new ones prefixed by >>):

   arch/powerpc/platforms/powernv/opal-call.c: In function 'opal_call':
>> arch/powerpc/platforms/powernv/opal-call.c:119:5: warning: 'fn' is used uninitialized in this function [-Wuninitialized]
     119 |  if (fn) {
         |     ^

vim +/fn +119 arch/powerpc/platforms/powernv/opal-call.c

   102	
   103	typedef int64_t (*opal_v4_le_entry_fn)(uint64_t r3, uint64_t r4, uint64_t r5,
   104	                               uint64_t r6, uint64_t r7, uint64_t r8,
   105	                               uint64_t r9, uint64_t r10);
   106	
   107	static int64_t opal_call(int64_t a0, int64_t a1, int64_t a2, int64_t a3,
   108		     int64_t a4, int64_t a5, int64_t a6, int64_t a7, int64_t opcode)
   109	{
   110		unsigned long flags;
   111		unsigned long msr = mfmsr();
   112		bool mmu = (msr & (MSR_IR|MSR_DR));
   113		int64_t ret;
   114		opal_v4_le_entry_fn fn;
   115	
   116		if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN))
   117			fn = (opal_v4_le_entry_fn)(opal.v4_le_entry);
   118	
 > 119		if (fn) {
   120			if (!mmu) {
   121				BUG_ON(msr & MSR_EE);
   122				ret = fn(opcode, a0, a1, a2, a3, a4, a5, a6);
   123				return ret;
   124			}
   125	
   126			local_irq_save(flags);
   127			hard_irq_disable(); /* XXX r13 */
   128			msr &= ~MSR_EE;
   129			mtmsr(msr & ~(MSR_IR|MSR_DR));
   130	
   131			ret = fn(opcode, a0, a1, a2, a3, a4, a5, a6);
   132	
   133			mtmsr(msr);
   134			local_irq_restore(flags);
   135	
   136			return ret;
   137		}
   138	
   139		msr &= ~MSR_EE;
   140	
   141		if (unlikely(!mmu))
   142			return __opal_call(a0, a1, a2, a3, a4, a5, a6, a7, opcode, msr);
   143	
   144		local_save_flags(flags);
   145		hard_irq_disable();
   146	
   147		if (DO_TRACE) {
   148			ret = __opal_call_trace(a0, a1, a2, a3, a4, a5, a6, a7, opcode, msr);
   149		} else {
   150			ret = __opal_call(a0, a1, a2, a3, a4, a5, a6, a7, opcode, msr);
   151		}
   152	
   153		local_irq_restore(flags);
   154	
   155		return ret;
   156	}
   157	

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