Re: [patch] edac i5000: fix pointer math in i5000_get_mc_regs()

walter harms
2012-03-02T19:20:59Z

Am 02.03.2012 20:09, schrieb Dan Carpenter:
> On Fri, Mar 02, 2012 at 10:00:06AM +0100, walter harms wrote:
>>> diff --git a/drivers/edac/i5000_edac.c b/drivers/edac/i5000_edac.c
>>> index 4dc3ac2..fcdc4ab 100644
>>> --- a/drivers/edac/i5000_edac.c
>>> +++ b/drivers/edac/i5000_edac.c
>>> @@ -1130,7 +1130,7 @@ static void i5000_get_mc_regs(struct mem_ctl_info *mci)
>>> pci_read_config_dword(pvt->system_address, AMBASE,
>>> (u32 *) & pvt->ambase);
>>> pci_read_config_dword(pvt->system_address, AMBASE + sizeof(u32),
>>> - ((u32 *) & pvt->ambase) + sizeof(u32));
>>> + (u32 *)((char *) &pvt->ambase + sizeof(u32)));
>>>
>>> maxdimmperch = pvt->maxdimmperch;
>>> maxch = pvt->maxch;
>>
>> i think this is hard to understand. personally i would prefer a union or other
>> more obvious solutions. my suggestion would be to get rid of this.
>>
>> u32 bottom,top;
>> pci_read_config_dword(pvt->system_address, AMBASE,
>> &bottom);
>> pci_read_config_dword(pvt->system_address, AMBASE+ sizeof(u32),
>> &top);
>> maxdimmperch=(u64)top<<32|bottom;
>>
>> you can find this pattern in other parts of the kernel also.
>>
>
> Sure. I want to do this again anyway because I see I've missed some
> other parts which have the same bug. I'll resend a patch later.
>
> regards,
> dan carpenter

I have no idea how ofter a64bit value is need but perhaps is pci_read_config_qword()
an option ?

re,
wh