In place kexec

[Eric W. Biederman]

"H. Peter Anvin" <hpa at zytor.com> writes:

> On 07/29/2010 12:55 PM, Randy Dunlap wrote:
>>>
>>> And device_shutdown calls every drivers .shutdown method.
>>>
>>> Things like this are always a driver problem.
>> 
>> so is there a default .shutdown method for drivers that do not specify one?
>> 
>> like the qla2xxx driver does not.
>> 
>
> If it doesn't, even if bus mastering gets shut off at the core level,
> there is a risk that is clobbers data when it turns it back on if the
> initialization sequence is problematic.

There isn't a bus master shut off at the core level.  When we did
the original analysis it turned out that the bus mastering bit
was implemented on a lot of devices in advisory way, so it didn't
make sense to count on it.

That said it looks like the code to do the shutdown is in
qla2x00_remove_one so it should be too hard if someone cared to
extract just the hardware bits.

Eric