From: Will Deacon <will.deacon@arm.com>
To: McClintock Matthew-B29882 <B29882@freescale.com>
Cc: "linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
Joonyoung Shim <jy0922.shim@samsung.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: ARM kexec SMP problem using exynos4210
Date: Wed, 11 Jan 2012 17:42:06 +0000 [thread overview]
Message-ID: <20120111174206.GD29015@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <CAEsOVNfWdHfy3XinAd836RqUpj6hF+7B8Af-3+vX14XuDV1niQ@mail.gmail.com>
On Wed, Jan 11, 2012 at 05:20:43PM +0000, McClintock Matthew-B29882 wrote:
> On Wed, Jan 11, 2012 at 5:03 AM, Will Deacon <will.deacon@arm.com> wrote:
> > On Wed, Jan 11, 2012 at 10:23:18AM +0000, Joonyoung Shim wrote:
> >> One more question, generally boot cpu is first cpu(cpu0). If current
> >> cpu is secondary cpu(cpu1), smp_send_stop of machine_shutdown will stop
> >> first cpu and next kernel will try to boot on secondary cpu. Is it
> >> possible?
> >
> > I added the cpu_logical_map stuff for this, so the kernel can handle it.
> > That said, your platform may have restrictions about the boot CPU so if it
> > doesn't work, you'll need to taskset the kexec command to CPU 0.
>
> Would this negatively effect kdump though where you might not be able
> to switch back to cpu0? I think It's best to be able to boot on any
> core.
Ideally, we would boot on any core. That's what the logical map is for. The
problem is that you may have hardware restrictions that prevent this (for
example, the secure monitor on OMAP4 is, I believe, only present on CPU 0).
Will
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WARNING: multiple messages have this Message-ID (diff)
From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: ARM kexec SMP problem using exynos4210
Date: Wed, 11 Jan 2012 17:42:06 +0000 [thread overview]
Message-ID: <20120111174206.GD29015@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <CAEsOVNfWdHfy3XinAd836RqUpj6hF+7B8Af-3+vX14XuDV1niQ@mail.gmail.com>
On Wed, Jan 11, 2012 at 05:20:43PM +0000, McClintock Matthew-B29882 wrote:
> On Wed, Jan 11, 2012 at 5:03 AM, Will Deacon <will.deacon@arm.com> wrote:
> > On Wed, Jan 11, 2012 at 10:23:18AM +0000, Joonyoung Shim wrote:
> >> One more question, generally boot cpu is first cpu(cpu0). If current
> >> cpu is secondary cpu(cpu1), smp_send_stop of machine_shutdown will stop
> >> first cpu and next kernel will try to boot on secondary cpu. Is it
> >> possible?
> >
> > I added the cpu_logical_map stuff for this, so the kernel can handle it.
> > That said, your platform may have restrictions about the boot CPU so if it
> > doesn't work, you'll need to taskset the kexec command to CPU 0.
>
> Would this negatively effect kdump though where you might not be able
> to switch back to cpu0? I think It's best to be able to boot on any
> core.
Ideally, we would boot on any core. That's what the logical map is for. The
problem is that you may have hardware restrictions that prevent this (for
example, the secure monitor on OMAP4 is, I believe, only present on CPU 0).
Will
next prev parent reply other threads:[~2012-01-11 17:42 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-11 8:35 ARM kexec SMP problem using exynos4210 Joonyoung Shim
2012-01-11 10:06 ` Will Deacon
2012-01-11 10:06 ` Will Deacon
2012-01-11 10:23 ` Joonyoung Shim
2012-01-11 10:23 ` Joonyoung Shim
2012-01-11 11:03 ` Will Deacon
2012-01-11 11:03 ` Will Deacon
2012-01-11 17:20 ` McClintock Matthew-B29882
2012-01-11 17:20 ` McClintock Matthew-B29882
2012-01-11 17:42 ` Will Deacon [this message]
2012-01-11 17:42 ` Will Deacon
-- strict thread matches above, loose matches on Subject: below --
2012-01-11 8:45 Joonyoung Shim
2012-01-11 8:45 ` Joonyoung Shim
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