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Subject: Re: [PATCH 1/1] x86/platform/x86: Fix count of CHas on
 multi-pci-segment arches
From: "Liang, Kan" <kan.liang@linux.intel.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Kroening, Gary" <gary.kroening@hpe.com>,
        "mingo@redhat.com" <mingo@redhat.com>, "hpa@zytor.com" <hpa@zytor.com>,
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Date: Tue, 13 Mar 2018 13:42:55 -0400
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On 3/13/2018 1:16 PM, Liang, Kan wrote:
> 
> 
> On 3/13/2018 11:58 AM, Andy Shevchenko wrote:
>> On Tue, Mar 13, 2018 at 3:42 AM, Liang, Kan 
>> <kan.liang@linux.intel.com> wrote:
>>
>>> +#define SKX_CAPID6             0x9c
>>> +#define SKX_CHA_BIT_WIDTH      28
>>> +
>>>   static int skx_count_chabox(void)
>>>   {
>>> +       struct pci_dev *dev = NULL;
>>> +       u32 val = 0;
>>>
>>
>>> +       dev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x2083, dev);
>>> +       if (!dev)
>>> +               return 0;
>>
>> Where is pci_dev_put()?
>>
>>>
>>> +       pci_read_config_dword(dev, SKX_CAPID6, &val);
>>> +       return bitmap_weight((unsigned long *)&val, SKX_CHA_BIT_WIDTH);
>>
>> UB is here.
>> Fix is simple, use unsigned long and drop this ugly casting.
>>

Just noticed that we have to do casting anyway.
pci_read_config_dword uses u32.
bitmap_weight uses unsigned long.

Thanks,
Kan