Re: [Fastboot] Re: Announce: dumpfs v0.01 - common RAS output API

Jesse Barnes
2004-07-28T22:54:49Z

On Wednesday, July 28, 2004 3:42 pm, Andrew Morton wrote:
> But they're welcome to do that: the memory for the DMA transfer has
> already been allocated and our new universe will not be touching it.

Yeah, for the most part that should be ok. We can be paranoid about
misdirected DMA later... (Some platforms will let you protect memory regions
at the chipset level, so it seems like the new kernel should be so protected
until it's actually jumped to by kexec, but prior to unprotecting it you'd
want to make sure that a bad DMA from the broken kernel doesn't hose it.)

> What we need to do is to ensure that the new kexec-ed kernel appropriately
> whacks the devices to stop any in-progress operations. So it's the probe()
> and open() routines which need to get the device into a sane state, not the
> shutdown routines.

That makes sense, and means that drivers may want to call a shutdown-like
routine in their probe functions to make sure their device is in a known
state before starting. But all of this is very driver specific it seems.

Jesse