[PATCH 2/2] ARM: kexec: Check segment memory addresses

Will Deacon will.deacon at arm.com
Fri Sep 7 06:04:22 EDT 2012

On Fri, Sep 07, 2012 at 09:49:38AM +0100, Russell King - ARM Linux wrote:
> On Fri, Sep 07, 2012 at 09:41:00AM +0100, Matthew Leach wrote:
> > Ensure that the memory regions that are set within the segments
> > correspond to physical contiguous memory regions.
> > 
> > Reviewed-by: Simon Horman <horms at verge.net.au>
> > Reviewed-by: Will Deacon <will.deacon at arm.com>
> > Signed-off-by: Matthew Leach <matthew.leach at arm.com>
> What about platforms which pull out bits of physical RAM from memblock
> via arm_memblock_steal() ?  Doesn't this mean such platforms will reduce
> their available memory on each subsequent kexec?

I don't think that will happen. All that kexec does is check that the
location where it wants to load the new kernel is physically contiguous -- the
memblock configuration is not inherited by the target kernel.

What *might* happen is that a memblock_steal on the host kernel could cause
the kexec to fail with -EINVAL if the area removed corresponds to the area
where the target kernel wants to be loaded. I think this is correct
behaviour, because we have no idea what the stolen region is being used for.


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