From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v26 0/7] arm64: add kdump support
Date: Mon, 19 Sep 2016 17:10:27 +0100 [thread overview]
Message-ID: <CAKv+Gu-pDS8C9uAkWq3mbuT2TZ9G6h-XTEd75fqaZv74kQ4WuQ@mail.gmail.com> (raw)
In-Reply-To: <57E00CDC.70403@arm.com>
On 19 September 2016 at 17:05, James Morse <james.morse@arm.com> wrote:
> On 16/09/16 21:17, Ard Biesheuvel wrote:
>> On 16 September 2016 at 17:04, James Morse <james.morse@arm.com> wrote:
>>> Mark, Ard, how does/will reserved-memory work on an APCI only system?
>>
>> It works by accident, at the moment. We used to ignore both
>> /memreserve/s and the /reserved-memory node, but due to some unrelated
>> refactoring, we ended up honouring the reserved-memory node when
>> booting via UEFI
>
> Okay, so kdump probably shouldn't rely on this behaviour...
>
No, but I would still like to keep /reserved-memory node support for
dynamic ranges, since they are guaranteed not to contain anything
'magic' left behind by the firmware. So if we keep /that/, keeping
static allocation support (with validation, as I proposed in the
series I quoted) is only a small step.
--
Ard.
> For an acpi-only system, we could get reserve_crashkernel() to copy the uefi
> memory map into the reserved region, changing the region types for existing
> kernel memory to EfiReservedMemoryType (for example) and fixing up the reserved
> region boundaries.
>
> This second memory map could then be added alongside the real one in the
> DT/chosen, and used in preference the second time we go through uefi_init() in
> the crash kernel.
>
> kexec-tools would still need to keep the '/reserved-memory' node for non-uefi
> systems.
>
> Doing this doesn't depend on userspace, and means the uefi memory map is still
> the one and only true source of memory layout information. If fixing it like
> this is valid I don't think it should block kdump.
>
> ... I will think about this some more before trying to put it together.
>
>
>
> Thanks,
>
> James
WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: James Morse <james.morse@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Geoff Levand <geoff@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
Dave Young <dyoung@redhat.com>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v26 0/7] arm64: add kdump support
Date: Mon, 19 Sep 2016 17:10:27 +0100 [thread overview]
Message-ID: <CAKv+Gu-pDS8C9uAkWq3mbuT2TZ9G6h-XTEd75fqaZv74kQ4WuQ@mail.gmail.com> (raw)
In-Reply-To: <57E00CDC.70403@arm.com>
On 19 September 2016 at 17:05, James Morse <james.morse@arm.com> wrote:
> On 16/09/16 21:17, Ard Biesheuvel wrote:
>> On 16 September 2016 at 17:04, James Morse <james.morse@arm.com> wrote:
>>> Mark, Ard, how does/will reserved-memory work on an APCI only system?
>>
>> It works by accident, at the moment. We used to ignore both
>> /memreserve/s and the /reserved-memory node, but due to some unrelated
>> refactoring, we ended up honouring the reserved-memory node when
>> booting via UEFI
>
> Okay, so kdump probably shouldn't rely on this behaviour...
>
No, but I would still like to keep /reserved-memory node support for
dynamic ranges, since they are guaranteed not to contain anything
'magic' left behind by the firmware. So if we keep /that/, keeping
static allocation support (with validation, as I proposed in the
series I quoted) is only a small step.
--
Ard.
> For an acpi-only system, we could get reserve_crashkernel() to copy the uefi
> memory map into the reserved region, changing the region types for existing
> kernel memory to EfiReservedMemoryType (for example) and fixing up the reserved
> region boundaries.
>
> This second memory map could then be added alongside the real one in the
> DT/chosen, and used in preference the second time we go through uefi_init() in
> the crash kernel.
>
> kexec-tools would still need to keep the '/reserved-memory' node for non-uefi
> systems.
>
> Doing this doesn't depend on userspace, and means the uefi memory map is still
> the one and only true source of memory layout information. If fixing it like
> this is valid I don't think it should block kdump.
>
> ... I will think about this some more before trying to put it together.
>
>
>
> Thanks,
>
> James
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next prev parent reply other threads:[~2016-09-19 16:10 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-07 4:29 [PATCH v26 0/7] arm64: add kdump support AKASHI Takahiro
2016-09-07 4:29 ` AKASHI Takahiro
2016-09-07 4:29 ` [PATCH v26 1/7] arm64: kdump: reserve memory for crash dump kernel AKASHI Takahiro
2016-09-07 4:29 ` AKASHI Takahiro
2016-09-22 10:23 ` Matthias Bruger
2016-09-22 10:23 ` Matthias Bruger
2016-09-23 8:37 ` AKASHI Takahiro
2016-09-23 8:37 ` AKASHI Takahiro
2016-09-07 4:29 ` [PATCH v26 2/7] arm64: kdump: implement machine_crash_shutdown() AKASHI Takahiro
2016-09-07 4:29 ` AKASHI Takahiro
2016-09-14 18:09 ` James Morse
2016-09-14 18:09 ` James Morse
2016-09-15 8:13 ` Marc Zyngier
2016-09-15 8:13 ` Marc Zyngier
2016-09-16 3:21 ` AKASHI Takahiro
2016-09-16 3:21 ` AKASHI Takahiro
2016-09-16 14:49 ` James Morse
2016-09-16 14:49 ` James Morse
2016-09-20 7:36 ` AKASHI Takahiro
2016-09-20 7:36 ` AKASHI Takahiro
2016-09-07 4:29 ` [PATCH v26 3/7] arm64: kdump: add kdump support AKASHI Takahiro
2016-09-07 4:29 ` AKASHI Takahiro
2016-09-16 14:50 ` James Morse
2016-09-16 14:50 ` James Morse
2016-09-20 7:46 ` AKASHI Takahiro
2016-09-20 7:46 ` AKASHI Takahiro
2016-09-22 15:50 ` Matthias Brugger
2016-09-22 15:50 ` Matthias Brugger
2016-09-07 4:29 ` [PATCH v26 4/7] arm64: kdump: add VMCOREINFO's for user-space coredump tools AKASHI Takahiro
2016-09-07 4:29 ` AKASHI Takahiro
2016-09-16 16:04 ` James Morse
2016-09-16 16:04 ` James Morse
2016-09-07 4:29 ` [PATCH v26 5/7] arm64: kdump: enable kdump in the arm64 defconfig AKASHI Takahiro
2016-09-07 4:29 ` AKASHI Takahiro
2016-09-07 4:29 ` [PATCH v26 6/7] arm64: kdump: update a kernel doc AKASHI Takahiro
2016-09-07 4:29 ` AKASHI Takahiro
2016-09-16 16:08 ` James Morse
2016-09-16 16:08 ` James Morse
2016-09-20 8:27 ` AKASHI Takahiro
2016-09-20 8:27 ` AKASHI Takahiro
2016-09-26 17:21 ` Matthias Brugger
2016-09-26 17:21 ` Matthias Brugger
[not found] ` <20160907042908.6232-1-takahiro.akashi-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-09-07 4:32 ` [PATCH v26 7/7] Documentation: dt: chosen properties for arm64 kdump AKASHI Takahiro
2016-09-07 4:32 ` AKASHI Takahiro
2016-09-07 4:32 ` AKASHI Takahiro
[not found] ` <20160907043203.6309-1-takahiro.akashi-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-09-16 13:03 ` Rob Herring
2016-09-16 13:03 ` Rob Herring
2016-09-16 13:03 ` Rob Herring
2016-09-07 4:37 ` [PATCH v26 0/7] arm64: add kdump support AKASHI Takahiro
2016-09-07 4:37 ` AKASHI Takahiro
2016-09-16 16:04 ` James Morse
2016-09-16 16:04 ` James Morse
2016-09-16 20:17 ` Ard Biesheuvel
2016-09-16 20:17 ` Ard Biesheuvel
2016-09-19 16:05 ` James Morse
2016-09-19 16:05 ` James Morse
2016-09-19 16:10 ` Ard Biesheuvel [this message]
2016-09-19 16:10 ` Ard Biesheuvel
2016-09-21 7:42 ` AKASHI Takahiro
2016-09-21 7:42 ` AKASHI Takahiro
2016-09-21 7:33 ` AKASHI Takahiro
2016-09-21 7:33 ` AKASHI Takahiro
2016-10-03 7:54 ` Manish Jaggi
2016-10-03 7:54 ` Manish Jaggi
2016-10-03 11:04 ` AKASHI Takahiro
2016-10-03 11:04 ` AKASHI Takahiro
2016-10-03 12:41 ` Manish Jaggi
2016-10-03 12:41 ` Manish Jaggi
2016-10-04 2:56 ` AKASHI Takahiro
2016-10-04 2:56 ` AKASHI Takahiro
2016-10-04 9:46 ` James Morse
2016-10-04 9:46 ` James Morse
2016-10-04 10:05 ` Manish Jaggi
2016-10-04 10:05 ` Manish Jaggi
2016-10-04 10:53 ` James Morse
2016-10-04 10:53 ` James Morse
2016-10-04 13:23 ` Manish Jaggi
2016-10-04 13:23 ` Manish Jaggi
2016-10-05 5:48 ` AKASHI Takahiro
2016-10-05 5:48 ` AKASHI Takahiro
2016-10-05 5:41 ` AKASHI Takahiro
2016-10-05 5:41 ` AKASHI Takahiro
2016-10-04 10:18 ` Mark Rutland
2016-10-04 10:18 ` Mark Rutland
2016-10-17 15:41 ` Ruslan Bilovol
2016-10-17 15:41 ` Ruslan Bilovol
2016-10-18 6:26 ` AKASHI Takahiro
2016-10-18 6:26 ` AKASHI Takahiro
2016-11-01 12:19 ` Ruslan Bilovol
2016-11-01 12:19 ` Ruslan Bilovol
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