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From: takahiro.akashi@linaro.org (AKASHI Takahiro)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v32 07/13] arm64: hibernate: preserve kdump image around hibernation
Date: Thu, 16 Feb 2017 18:52:15 +0900	[thread overview]
Message-ID: <20170216095214.GF18445@linaro.org> (raw)
In-Reply-To: <58A445B3.4080608@arm.com>

On Wed, Feb 15, 2017 at 12:12:35PM +0000, James Morse wrote:
> Hi Akashi,
> 
> On 07/02/17 08:08, AKASHI Takahiro wrote:
> > Since arch_kexec_protect_crashkres() removes a mapping for crash dump
> > kernel memory, the loaded contents won't be preserved around hibernation.
> > 
> > In this patch, arch_kexec_(un)protect_crashkres() are additionally called
> > before/after hibernation so that the relevant region will be mapped again
> > and restored just as the other memory regions are.
> 
> Reviewed-by: James Morse <james.morse@arm.com>

Thank you very much.

> A quick test of this took longer than expected (writing to a slow usb device),

Really? I use a uSD card on hikey as a swap device, and it takes just
a few moments to save a hibernate image although I do the test right after
the system comes up.

> I
> suspect it is save/restoring the whole crash region (which I don't think is a
> problem).

Now that we have only page-level mappings for the crash region,
it might be possible to mark all the unused pages "reserved"
in arch_kexec_unprotect_crashkres() if called in hibernate.

-Takahiro AKASHI

> If someone turns out to use this combination of features I will look
> at improving this, (almost certainly requires core-code changes).
> 
> 
> Thanks,
> 
> James

  reply	other threads:[~2017-02-16  9:52 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-07  8:06 [PATCH v32 00/13] arm64: add kdump support AKASHI Takahiro
2017-02-07  8:08 ` [PATCH v32 01/13] memblock: add memblock_clear_nomap() AKASHI Takahiro
2017-02-07  8:08 ` [PATCH v32 02/13] memblock: add memblock_cap_memory_range() AKASHI Takahiro
2017-02-07  8:08 ` [PATCH v32 03/13] arm64: limit memory regions based on DT property, usable-memory-range AKASHI Takahiro
2017-02-07  8:08 ` [PATCH v32 04/13] arm64: kdump: reserve memory for crash dump kernel AKASHI Takahiro
2017-02-07  8:08 ` [PATCH v32 05/13] arm64: mm: allow for unmapping part of kernel mapping AKASHI Takahiro
2017-02-07  8:08 ` [PATCH v32 06/13] arm64: kdump: protect crash dump kernel memory AKASHI Takahiro
2017-02-17 16:08   ` James Morse
2017-02-07  8:08 ` [PATCH v32 07/13] arm64: hibernate: preserve kdump image around hibernation AKASHI Takahiro
2017-02-15 12:12   ` James Morse
2017-02-16  9:52     ` AKASHI Takahiro [this message]
2017-02-07  8:09 ` [PATCH v32 08/13] arm64: kdump: implement machine_crash_shutdown() AKASHI Takahiro
2017-02-07  8:09 ` [PATCH v32 09/13] arm64: kdump: add VMCOREINFO's for user-space tools AKASHI Takahiro
2017-02-07  8:09 ` [PATCH v32 10/13] arm64: kdump: provide /proc/vmcore file AKASHI Takahiro
2017-02-07  8:09 ` [PATCH v32 11/13] arm64: kdump: enable kdump in defconfig AKASHI Takahiro
2017-02-07  8:09 ` [PATCH v32 12/13] Documentation: kdump: describe arm64 port AKASHI Takahiro
2017-02-07  8:10 ` [PATCH v32 13/13] Documentation: dt: chosen properties for arm64 kdump AKASHI Takahiro
2017-02-08  5:39 ` [PATCH v32 00/13] arm64: add kdump support Pratyush Anand
2017-03-02  0:51 ` Goel, Sameer
2017-03-02 10:34   ` AKASHI Takahiro

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