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: 1) "mem=" boot parameter must be specified on crash dump kernel 2) 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
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