[PATCH v24 0/9] arm64: add kdump support
Manish Jaggi
mjaggi at caviumnetworks.com
Tue Sep 6 09:15:36 PDT 2016
On 09/06/2016 09:03 PM, Marc Zyngier wrote:
> On 05/09/16 13:42, Manish Jaggi wrote:
>>
>>
>> On 09/05/2016 01:45 PM, AKASHI Takahiro wrote:
>>> [Cc: Marc]
>>>
>>> On Fri, Sep 02, 2016 at 06:23:25PM +0530, Manish Jaggi wrote:
>>>>
>>>>
>>>> On 08/31/2016 11:01 AM, AKASHI Takahiro wrote:
>>>>> Manish,
>>>>>
>>>>> Thank you for testing my kdump and reporting issues.
>>>>>
>>>>> On Wed, Aug 31, 2016 at 09:11:52AM +0530, Manish Jaggi wrote:
>>>>>> Hi Akashi,
>>>>>>
>>>>>> On 08/09/2016 07:22 AM, AKASHI Takahiro wrote:
>>>>>>> This patch series adds kdump support on arm64.
>>>>>>>
>>>>>>> To load a crash-dump kernel to the systems, a series of patches to
>>>>>>> kexec-tools, which have not yet been merged upstream, are needed.
>>>>>>> Please use my kdump patches [1].
>>>>>>>
>>>>>>> To examine vmcore (/proc/vmcore) on a crash-dump kernel, you can use
>>>>>>> - crash utility (coming v7.1.6 or later) [2]
>>>>>>> (Necessary patches have already been queued in the master.)
>>>>>>>
>>>>>>> [1] T.B.D.
>>>>>>> [2] https://github.com/crash-utility/crash.git
>>>>>>>
>>>>>>> Changes for v24 (Aug 9, 2016):
>>>>>>> o Rebase to Linux-4.8-rc1
>>>>>>> o Update descriptions about newly added DT proerties
>>>>>>>
>>>>>>> Changes for v23 (July 26, 2016):
>>>>>>>
>>>>>>> o Move memblock_reserve() to a single place in reserve_crashkernel()
>>>>>>> o Use cpu_park_loop() in ipi_cpu_crash_stop()
>>>>>>> o Always enforce ARCH_LOW_ADDRESS_LIMIT to the memory range of crash kernel
>>>>>>> o Re-implement fdt_enforce_memory_region() to remove non-reserve regions
>>>>>>> (for ACPI) from usable memory at crash kernel
>>>>>>>
>>>>>>> Changes for v22 (July 12, 2016):
>>>>>>>
>>>>>>> o Export "crashkernel-base" and "crashkernel-size" via device-tree,
>>>>>>> and add some descriptions about them in chosen.txt
>>>>>>> o Rename "usable-memory" to "usable-memory-range" to avoid inconsistency
>>>>>>> with powerpc's "usable-memory"
>>>>>>> o Make cosmetic changes regarding "ifdef" usage
>>>>>>> o Correct some wordings in kdump.txt
>>>>>>>
>>>>>>> Changes for v21 (July 6, 2016):
>>>>>>>
>>>>>>> o Remove kexec patches.
>>>>>>> o Rebase to arm64's for-next/core (Linux-4.7-rc4 based).
>>>>>>> o Clarify the description about kvm in kdump.txt.
>>>>>>>
>>>>>>> See the following link [3] for older changes:
>>>>>>> [3] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-June/438780.html
>>>>>>>
>>>>>>> AKASHI Takahiro (8):
>>>>>>> arm64: kdump: reserve memory for crash dump kernel
>>>>>>> memblock: add memblock_cap_memory_range()
>>>>>>> arm64: limit memory regions based on DT property, usable-memory-range
>>>>>>> arm64: kdump: implement machine_crash_shutdown()
>>>>>>> arm64: kdump: add kdump support
>>>>>>> arm64: kdump: add VMCOREINFO's for user-space coredump tools
>>>>>>> arm64: kdump: enable kdump in the arm64 defconfig
>>>>>>> arm64: kdump: update a kernel doc
>>>>>>>
>>>>>>> James Morse (1):
>>>>>>> Documentation: dt: chosen properties for arm64 kdump
>>>>>>>
>>>>>>> Documentation/devicetree/bindings/chosen.txt | 45 ++++++
>>>>>>> Documentation/kdump/kdump.txt | 16 ++-
>>>>>>> arch/arm64/Kconfig | 11 ++
>>>>>>> arch/arm64/configs/defconfig | 1 +
>>>>>>> arch/arm64/include/asm/hardirq.h | 2 +-
>>>>>>> arch/arm64/include/asm/kexec.h | 41 +++++-
>>>>>>> arch/arm64/include/asm/smp.h | 2 +
>>>>>>> arch/arm64/kernel/Makefile | 1 +
>>>>>>> arch/arm64/kernel/crash_dump.c | 71 ++++++++++
>>>>>>> arch/arm64/kernel/machine_kexec.c | 67 ++++++++-
>>>>>>> arch/arm64/kernel/setup.c | 7 +-
>>>>>>> arch/arm64/kernel/smp.c | 63 +++++++++
>>>>>>> arch/arm64/mm/init.c | 202 +++++++++++++++++++++++++++
>>>>>>> include/linux/memblock.h | 1 +
>>>>>>> mm/memblock.c | 28 ++++
>>>>>>> 15 files changed, 551 insertions(+), 7 deletions(-)
>>>>>>> create mode 100644 arch/arm64/kernel/crash_dump.c
>>>>>>>
>>>>>> Couple of points
>>>>>> a) Just a note, while testing, the crashkernel reserved memory should be less than ARCH_LOW_ADDRESS_LIMIT (=arm64_dma_phys_limit).
>>>>>
>>>>> I think that this is a common mistake not only for kdump, but also
>>>>> for general kernels.
>>>>> Since request_standard_resources() calls alloc_bootmem_low(),
>>>>> the kernel will panic if any of usable "System RAM" is located
>>>>> above ARCH_LOW_ADDRESS_LIMIT.
>>>>> For kdump, using "crashkernel=SS" notation is a convenient way
>>>>> to avoid this issue.
>>>>>
>>>>>> b) Has anyone tested this on a SoC with Gicv3 ITS ?
>>>>>> Should the GICD/R be reset prior to switching to crash kernel ?
>>>>>> I am seeing lot of GICv3: RWP timeout, gone fishing while crash kernel boots.
>>>>>
>>>>> I've never seen this kind of messages.
>>>>> I usually do my testing on a fast model.
>>>>> "compatible" of interrupt-controller is "arm,gic-v3."
>>>>>
>>>> I suspect gic_cpu_pm_notifier is not being called on any of the cores prior to start of crash kernel.
>>>> We might have to call it explicitly.
>>>
>>> I'm not sure that it is the cause, but anyway none of any cpu_pm_notifier's
>>> will be called at panic. That is the reason why "maxcpus=1" should be
>>> specified (for kdump on arm64).
>>>
>> What I meant was that since cpu_pm_notifier is not called before
>> crash kernel is started, GIC Distributor/re-distributor/ITS is not
>> set in quiescent state.
>
> Which is fine, they are not expected to be in a sane state anyway
> (that's what a crash is about...). The ITS now has provision to be put
> in a disabled state before being reinitialized. As for GICD, it is
> disabled before being reprogrammed, which should be enough.
>
>> In my setup the GICD_CTRL[RWP] bit is not cleared in the
>> crashkernels' distributor init function.
>
> Which instance is failing? The initial one (just after the initial
> disable)? Or the one called from gic_dist_config()?
>
In crash kernel, when the GICD_CTRL is set to 0x0, RWP is not getting clear.
And is never cleared for any subsequent writes.
> Thanks,
>
> M.
>
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