Hi Pratyush,
On 04/02/2015 12:56 AM, Pratyush Anand wrote:
Hi Akashi,
On Thursday 26 March 2015 01:58 PM, AKASHI Takahiro wrote:
This patch set enables kdump (crash dump kernel) support on arm64 on top of Geoff's kexec patchset.
In this version, there are some arm64-specific usage/constraints:
- "mem=" boot parameter must be specified on crash dump kernel
- Kvm will not be enabled on crash dump kernel even if configured
See commit messages and Documentation/kdump/kdump.txt for details.
The only concern I have is whether or not we can use the exact same kernel as both system kernel and crash dump kernel. The current arm64 kernel is not relocatable in the exact sense but I have no problems in using the same binary for testing kdump.
I tested the code with - ATF v1.1 + EDK2(UEFI) v3.0-rc0 - kernel v4.0-rc4 + Geoff' kexec v8 on Base fast model, using my yet-to-be-submitted kexec-tools [1]. You may want to start a kernel with the following boot parameter: crashkernel=64M@2240M and try $ kexec -p --load <vmlinux> --append ... $ echo c > /proc/sysrq-trigger
I tried to use your kdump patches for kernel and kexec-tools. I am not able to load the crash kernel properly.
I passed crashkernel=64M@259G (My 8GB RAM starts at 256G) to primary kernel.
Used following to load the crash kernel kexec -p --load vmlinux --append="$( cat /proc/cmdline ) maxcpus=1 mem=64M reset_devices"
I see:
kexec_load failed: Cannot assign requested address entry = 0x40c40005d0 flags = 0xb70001
What I noticed that arm64_load_other_segments does not calculate correct load address for purgatory or if I pass initrd then for that too within crash kernel allocated memory.
It seems that you hit the same problem that I mentioned in: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/334613.html
Please try my latest kexec-tools in my linaro repo (branch name is kdump/v0.11) and let me know the result.
Shouldn't we have a function similar to locate_dtb_in_crashmem for putgatory as well as initrd? I can try to fix this allocation, but I was just wondering if I understood correctly or I am missing something.
I don't think a function for purgatory is necessary since we try to find a hole just after dtb.
Thanks, -Takahiro AKASHI
~Pratyush
To examine vmcore (/proc/vmcore), you may use - gdb v7.7 or later - crash + a small patch (to recognize v4.0 kernel)
[1] https://git.linaro.org/people/takahiro.akashi/kexec-tools.git
AKASHI Takahiro (5): arm64: kdump: reserve memory for crash dump kernel arm64: kdump: implement machine_crash_shutdown() arm64: kdump: do not go into EL2 before starting a crash dump kernel arm64: add kdump support arm64: enable kdump in the arm64 defconfig
Documentation/kdump/kdump.txt | 31 ++++++++++++++- arch/arm64/Kconfig | 12 ++++++ arch/arm64/configs/defconfig | 1 + arch/arm64/include/asm/kexec.h | 34 +++++++++++++++- arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/crash_dump.c | 71 +++++++++++++++++++++++++++++++++ arch/arm64/kernel/machine_kexec.c | 55 +++++++++++++++++++++++++- arch/arm64/kernel/process.c | 7 +++- arch/arm64/kernel/setup.c | 78 +++++++++++++++++++++++++++++++++++++ arch/arm64/kernel/smp.c | 10 ++++- 10 files changed, 294 insertions(+), 6 deletions(-) create mode 100644 arch/arm64/kernel/crash_dump.c