From: Will Deacon <will.deacon@arm.com>
To: Stephen Warren <swarren@wwwdotorg.org>
Cc: Stephen Warren <swarren@nvidia.com>,
Peter De Schrijver <pdeschrijver@nvidia.com>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
Eric Biederman <ebiederm@xmission.com>,
Joseph Lo <josephl@nvidia.com>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] kexec: disable non-boot CPUs
Date: Sun, 23 Dec 2012 11:06:02 +0000 [thread overview]
Message-ID: <20121223110602.GA16237@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <50D371E2.1030807@wwwdotorg.org>
On Thu, Dec 20, 2012 at 08:15:30PM +0000, Stephen Warren wrote:
> On 12/20/2012 10:59 AM, Stephen Warren wrote:
> > On 12/20/2012 10:36 AM, Will Deacon wrote:
> >> I think you're better off using what we currently have and hanging your code
> >> off platform_cpu_kill.
> >
> > OK, I'll look into that. Joseph Lo just posted patches to implement
> > cpu_kill() on Tegra, which was needed to fix some issues in our hotplug
> > code anyway. Perhaps that will remove the need for any other changes...
>
> Will,
Hi Stephen,
> I just remembered one other advantage of disable_nonboot_cpus(); it
> always makes the kexec happen on the boot CPU. Without this, I believe
> it's random whether CPU0 or CPU1 performs the kexec. I suspect it's most
> likely to work if we can always kexec on the boot CPU rather than a
> random CPU?
It will be the same CPU as the one which made the kexec system call. If you
need to invoke this from a specific CPU, you currently have to do this in
userspace using something like the `taskset' utility. Linux can actually
boot on any physical CPU for ARM now (thanks to the logical map) but most
platforms have restrictions related to secure firmware.
Will
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prev parent reply other threads:[~2012-12-23 11:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-19 23:44 [PATCH] kexec: disable non-boot CPUs Stephen Warren
2012-12-19 23:55 ` Eric W. Biederman
2012-12-20 10:49 ` Will Deacon
2012-12-20 17:21 ` Stephen Warren
2012-12-20 17:36 ` Will Deacon
2012-12-20 17:59 ` Stephen Warren
2012-12-20 20:15 ` Stephen Warren
2012-12-23 11:06 ` Will Deacon [this message]
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