From: Stephen Warren <swarren@wwwdotorg.org>
To: Vijay Kilari <vijay.kilari@gmail.com>
Cc: "linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
"Prasun.Kapoor@caviumnetworks.com"
<Prasun.Kapoor@caviumnetworks.com>,
Will Deacon <will.deacon@arm.com>,
Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] ARM: kexec: offline non panic CPUs on Kdump panic
Date: Tue, 30 Jul 2013 10:59:13 -0600 [thread overview]
Message-ID: <51F7F0E1.5030200@wwwdotorg.org> (raw)
In-Reply-To: <CALicx6ugumPG__rSAsTS95SH=6fTGqhpPFsQ8bLG-u-fbk0=pQ@mail.gmail.com>
On 07/30/2013 04:37 AM, Vijay Kilari wrote:
> On Fri, Jul 26, 2013 at 10:38 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
...
>> Does a kernel that's used as the crash kernel guarantee:
>>
>> * Never to re-use the memory that was used by the previous kernel, so
>> that the spin loop code/data won't be corrupted, ever, no matter how
>> long the crash recovery kernel runs.
>>
>> * Not use SMP, so there's never a need to re-activate the non-boot CPUs,
>> which might not work if they aren't truly disabled but rather just
>> running a pin loop?
>
> From cat /proc/iomem, normal kernel is executed from (0x80xxxxxx) with crash
> kernel reserved 64M@0xa0000000
>
> 80000000-bfffffff : System RAM
> 80008000-805aeddf : Kernel code
> 805e2000-8063e427 : Kernel data
> a0000000-a3ffffff : Crash kernel
>
> crash kernel is loaded to reserved memory location and is executed from there.
> I could confirm this from /proc/iomem when crash kernel is running
>
> a0000000-a3efffff : System RAM
> a0008000-a05aeddf : Kernel code
> a05e2000-a063e427 : Kernel data
OK, but in the crash dump kernel, is 80008000..8063e427 reserved as
well, which would guarantee that the spin loop being executed by the
non-crash CPUs won't be corrupted?
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next prev parent reply other threads:[~2013-07-30 16:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-26 5:41 [PATCH] ARM: kexec: offline non panic CPUs on Kdump panic vijay.kilari
2013-07-26 10:49 ` Will Deacon
2013-07-26 17:08 ` Stephen Warren
2013-07-26 17:11 ` Will Deacon
2013-07-30 10:37 ` Vijay Kilari
2013-07-30 16:59 ` Stephen Warren [this message]
2013-07-31 11:37 ` Vijay Kilari
2013-07-31 17:14 ` Stephen Warren
2013-08-01 13:49 ` Vijay Kilari
2013-08-01 16:25 ` Stephen Warren
2013-08-12 12:18 ` Vijay Kilari
2013-08-13 11:18 ` Will Deacon
2013-07-26 17:05 ` Stephen Warren
2013-07-30 10:05 ` Vijay Kilari
2013-07-30 16:57 ` Stephen Warren
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