From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: James Morse <james.morse@arm.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>,
James Morris <jmorris@namei.org>, Sasha Levin <sashal@kernel.org>,
Eric Biederman <ebiederm@xmission.com>,
kexec mailing list <kexec@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Catalin Marinas <catalin.marinas@arm.com>,
will@kernel.org,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [v1 0/5] allow to reserve memory for normal kexec kernel
Date: Wed, 10 Jul 2019 11:56:50 -0400 [thread overview]
Message-ID: <CA+CK2bBWis8TgyOmDhVgLYrOU95Za-UhSGSB3ufsjiNDt-Zd_w@mail.gmail.com> (raw)
In-Reply-To: <f9bea5bd-370a-47b5-8ad1-a30bd43d6cca@arm.com>
On Wed, Jul 10, 2019 at 11:19 AM James Morse <james.morse@arm.com> wrote:
>
> Hi Pasha,
>
> On 09/07/2019 14:07, Pavel Tatashin wrote:
> >>> Enabling MMU and D-Cache for relocation would essentially require the
> >>> same changes in kernel. Could you please share exactly why these were
> >>> not accepted upstream into kexec-tools?
> >>
> >> Because '--no-checks' is a much simpler alternative.
> >>
> >> More of the discussion:
> >> https://lore.kernel.org/linux-arm-kernel/5599813d-f83c-d154-287a-c131c48292ca@arm.com/
> >>
> >> While you can make purgatory a fully-fledged operating system, it doesn't really need to
> >> do anything on arm64. Errata-workarounds alone are a reason not do start down this path.
> >
> > Thank you James. I will summaries the information gathered from the
> > yesterday's/today's discussion and add it to the cover letter together
> > with ARM64 tag. I think, the patch series makes sense for ARM64 only,
> > unless there are other platforms that disable caching/MMU during
> > relocation.
>
> I'd prefer not to reserve additional memory for regular kexec just to avoid the relocation.
> If the kernel's relocation work is so painful we can investigate doing it while the MMU is
> enabled. If you can compare regular-kexec with kexec_file_load() you eliminate the
> purgatory part of the work.
Relocation time is exactly the same for regular-kexec and
kexec_file_load(). So, the relocation is indeed painful for our case.
I am working on adding MMU enabled kernel relocation.
Pasha
next prev parent reply other threads:[~2019-07-10 15:57 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-08 21:15 [v1 0/5] allow to reserve memory for normal kexec kernel Pavel Tatashin
2019-07-08 21:15 ` [v1 1/5] kexec: quiet down kexec reboot Pavel Tatashin
2019-07-08 21:15 ` [v1 2/5] kexec: add resource for normal kexec region Pavel Tatashin
2019-07-08 21:15 ` [v1 3/5] kexec: export common crashkernel/kexeckernel parser Pavel Tatashin
2019-07-08 21:15 ` [v1 4/5] kexec: use reserved memory for normal kexec reboot Pavel Tatashin
2019-07-08 21:15 ` [v1 5/5] arm64, kexec: reserve kexeckernel region Pavel Tatashin
2019-07-08 23:53 ` [v1 0/5] allow to reserve memory for normal kexec kernel Eric W. Biederman
2019-07-09 0:09 ` Pavel Tatashin
2019-07-09 10:18 ` James Morse
2019-07-09 10:36 ` Bhupesh Sharma
2019-07-09 10:55 ` Pavel Tatashin
2019-07-09 11:59 ` James Morse
2019-07-09 13:07 ` Pavel Tatashin
2019-07-10 15:19 ` James Morse
2019-07-10 15:56 ` Pavel Tatashin [this message]
2019-07-11 8:12 ` Vladimir Murzin
2019-07-11 12:26 ` Pavel Tatashin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CA+CK2bBWis8TgyOmDhVgLYrOU95Za-UhSGSB3ufsjiNDt-Zd_w@mail.gmail.com \
--to=pasha.tatashin@soleen.com \
--cc=bhsharma@redhat.com \
--cc=catalin.marinas@arm.com \
--cc=corbet@lwn.net \
--cc=ebiederm@xmission.com \
--cc=james.morse@arm.com \
--cc=jmorris@namei.org \
--cc=kexec@lists.infradead.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=sashal@kernel.org \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).