(2010/07/21 11:48), H. Peter Anvin wrote:
> On 07/20/2010 06:21 PM, Hidetoshi Seto wrote:
>> With v2.6.35-rc5, my x86-64 server doesn't boot but reports a
>> Completer Abort on lpfc card.
>>
>> The result of git-bisect is:
>> 6175ddf06b6172046a329e3abfd9c901a43efd2e is the first bad commit
>> commit 6175ddf06b6172046a329e3abfd9c901a43efd2e
>> Author: Brian Gerst <brgerst@xxxxxxxxx>
>> Date: Fri Feb 5 09:37:07 2010 -0500
>> x86: Clean up mem*io functions.
>>
>> What I found are:
>> - memcpy for 64bit uses movq if count >= 64 (arch/x86/lib/memcpy_64.S)
>> - memcpy_toio and memcpy_fromio have changed to use this memcpy by
>> the above commit.
>> - my debug shows that lpfc calls memcpy_toio with not-qword-aligned
>> addresses and count >= 64, e.g.:
>> memcpy_toio(0xffffc900118de004, 0xffff88047293d614, 124);
>> and it seems that it comes from:
>> [drivers/scsi/lpfc/lpfc_sli.c]
>> 4929 /* First copy mbox command data to HBA SLIM, skip past first
>> 4930 word */
>> 4931 to_slim = phba->MBslimaddr + sizeof (uint32_t);
>> 4932 lpfc_memcpy_to_slim(to_slim, &mb->un.varWords[0],
>> 4933 MAILBOX_CMD_SIZE - sizeof (uint32_t));
>>
>> Still I'm not sure what is wrong in software or hardware, however
>> I suppose that qword access to iomem is not always safe, so it will
>> be OK to back to use __inline_memcpy which uses movsl.
>>
>> I confirmed that my server (w/ lpfc) boots with 35-rc5 + this patch.
>>
>> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
>
> A driver should not use the memcpy-like instructions if it isn't set up
> to act as memory (meaning it can handle arbitrary byte enables.)
So then is this a problem of lpfc driver?
James, could you agree on that?
> The function it should be using is called, fairly counterintuitively,
> __iowrite32_copy(). It really should be called memcpy_toio32() or
> something similar.
>
> -hpa
It seems that lpfc already implemented lpfc_memcpy_{to,from}_slim()
as such memcpy_*io32, but limited use of it to on big endian platforms
only. Now lpfc can move to use it always, right?
Thanks,
H.Seto
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