[PATCH v24 0/9] arm64: add kdump support
AKASHI Takahiro
takahiro.akashi at linaro.org
Mon Sep 5 01:15:02 PDT 2016
[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).
-Takahiro AKASHI
> > Thanks,
> > -Takahiro AKASHI
> >
> >> Thanks,
> >> Manish
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