From: Balbir Singh <bsingharora@gmail•com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>,
linuxppc-dev@lists•ozlabs.org
Cc: Anton Blanchard <anton@au1•ibm.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
Subject: Re: [RFC/PATCH 3/4] powerpc/64/kexec: Copy image with MMU off when possible
Date: Fri, 8 Jul 2016 13:08:44 +1000 [thread overview]
Message-ID: <f1887661-e287-2235-ab72-0d2abdce7dfa@gmail.com> (raw)
In-Reply-To: <1467779707.13965.103.camel@kernel.crashing.org>
On 06/07/16 14:35, Benjamin Herrenschmidt wrote:
> 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@kernel•crashing.org>
> ---
> Currently only compile tested
This makes sense
Acked-by: Balbir Singh <bsingharora@gmail•com>
prev parent reply other threads:[~2016-07-08 3:08 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-06 4:35 [RFC/PATCH 3/4] powerpc/64/kexec: Copy image with MMU off when possible Benjamin Herrenschmidt
2016-07-08 3:08 ` Balbir Singh [this message]
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