Please read the following commits for arm64-specific constraints: arm64: kdump: reserve memory for crash dump kernel arm64: kdump: do not go into EL2 before starting a crash dump kernel
Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org --- Documentation/kdump/kdump.txt | 31 ++++++++++++++++++++++++++++++- arch/arm64/Kconfig | 12 ++++++++++++ 2 files changed, 42 insertions(+), 1 deletion(-)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index bc4bd5a..f9cf6f5 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -18,7 +18,7 @@ memory image to a dump file on the local disk, or across the network to a remote system.
Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64, -s390x and arm architectures. +s390x, arm and arm64 architectures.
When the system kernel boots, it reserves a small section of memory for the dump-capture kernel. This ensures that ongoing Direct Memory Access @@ -249,6 +249,29 @@ Dump-capture kernel config options (Arch Dependent, arm)
AUTO_ZRELADDR=y
+Dump-capture kernel config options (Arch Dependent, arm64) +---------------------------------------------------------- + +1) Disable symmetric multi-processing support under "Processor type and + features": + + CONFIG_SMP=n + + (If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line + when loading the dump-capture kernel, see section "Load the Dump-capture + Kernel".) + +2) Under uefi, the maximum memory size on the dump-capture kernel must be + limited by specifying: + + mem=X[MG] + + where X should be less than or equal to the size in "crashkernel=" + boot parameter. Kexec-tools will automatically add this. + +3) Currently, kvm will not be initialized on the dump-capture kernel even + if it is configured. + Extended crashkernel syntax ===========================
@@ -312,6 +335,7 @@ Boot into System Kernel any space below the alignment point may be overwritten by the dump-capture kernel, which means it is possible that the vmcore is not that precise as expected.
+ On arm64, use "crashkernel=Y@X".
Load the Dump-capture Kernel ============================ @@ -334,6 +358,8 @@ For s390x: - Use image or bzImage For arm: - Use zImage +For arm64: + - Use vmlinux
If you are using a uncompressed vmlinux image then use following command to load dump-capture kernel. @@ -377,6 +403,9 @@ For s390x: For arm: "1 maxcpus=1 reset_devices"
+For arm64: + "1 maxcpus=1 mem=X[MG] reset_devices" + Notes on loading the dump-capture kernel:
* By default, the ELF headers are stored in ELF64 format to support diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5a606d1..06a6ed4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -537,6 +537,18 @@ config KEXEC but it is independent of the system firmware. And like a reboot you can start any kernel with it, not just Linux.
+config CRASH_DUMP + bool "Build kdump crash kernel" + help + Generate crash dump after being started by kexec. This should + be normally only set in special crash dump kernels which are + loaded in the main kernel with kexec-tools into a specially + reserved region and then later executed after a crash by + kdump/kexec. The crash dump kernel must be compiled to a + memory address not used by the main kernel. + + For more details see Documentation/kdump/kdump.txt + config XEN_DOM0 def_bool y depends on XEN