[PATCH V2 4/5] powerpc/64/kexec: Copy image with MMU off when possible

Balbir Singh bsingharora at gmail.com
Tue Aug 23 10:21:13 AEST 2016



On 19/08/16 18:52, Aneesh Kumar K.V wrote:
> From: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> 
> Currently we turn the MMU off after copying the image, and we make
> sure there is no overlap between the hash table and the target pages
> in that case.
> 
> That doesn't work for Radix however. In that case, the page tables
> are scattered and we can't really enforce that the target of the
> image isn't overlapping one of them.
> 
> So instead, let's turn the MMU off before copying the image in radix
> mode. Thankfully, in radix mode, even under a hypervisor, we know we
> don't have the same kind of RMA limitations that hash mode has.
> 
> While at it, also turn the MMU off early when using hash in non-LPAR
> mode, that way we can get rid of the collision check completely.
> 
> Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>

Looks good

Acked-by: Balbir Singh <bsingharora at gmail.com>


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