Re: [PATCH v2 2/2] perf: ThunderX2: Add Cavium Thunderx2 SoC UNCORE PMU driver

[kbuild test robot]

Hi Ganapatrao,

[auto build test WARNING on linus/master]
[also build test WARNING on v4.12-rc3 next-20170531]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Ganapatrao-Kulkarni/perf-uncore-Adding-documentation-for-ThunderX2-pmu-uncore-driver/20170531-204518
config: i386-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All warnings (new ones prefixed by >>):

   drivers/perf/thunderx2_pmu.c: In function 'thunderx2_uncore_update':
>> drivers/perf/thunderx2_pmu.c:499:18: warning: left shift count >= width of type [-Wshift-count-overflow]
      delta = (((1UL << 32) - prev) + new);
                     ^~

vim +499 drivers/perf/thunderx2_pmu.c

   483		u64 delta;
   484		struct hw_perf_event *hwc = &event->hw;
   485		struct thunderx2_pmu_uncore_channel *pmu_uncore;
   486		enum thunderx2_uncore_type type;
   487	
   488		pmu_uncore = pmu_to_thunderx2_pmu_uncore(event->pmu);
   489		type = pmu_uncore->uncore_dev->type;
   490	
   491		if (pmu_uncore->uncore_dev->select_channel)
   492			pmu_uncore->uncore_dev->select_channel(event);
   493	
   494		new = reg_readl(hwc->event_base);
   495		prev = local64_xchg(&hwc->prev_count, new);
   496	
   497		/* handle rollover of counters */
   498		if (new < prev)
 > 499			delta = (((1UL << 32) - prev) + new);
   500		else
   501			delta = new - prev;
   502	
   503		local64_add(delta, &event->count);
   504	}
   505	
   506	enum thunderx2_uncore_type get_uncore_device_type(struct acpi_device *adev)
   507	{

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