[PATCH v21 1/8] arm64: kdump: reserve memory for crash dump kernel

Thiago Jung Bauermann bauerman at linux.vnet.ibm.com
Wed Jul 6 11:11:45 PDT 2016

Am Mittwoch, 06 Juli 2016, 16:52:19 schrieb AKASHI Takahiro:
> On the startup of primary kernel, the memory region used by crash dump
> kernel must be specified by "crashkernel=" kernel parameter.
> reserve_crashkernel() will allocate and reserve the region for later use.
> User space tools, like kexec-tools, will be able to find that region
> marked as "Crash kernel" in /proc/iomem.

On powerpc, userspace tools get everything from the device tree (exposed to 
userspace in /proc/device-tree/), not /proc/iomem.

In the case of the crashkernel reserved region, that information is in 
/chosen/linux,crashkernel-base and /chosen/linux,crashkernel-size.

Either way is fine I think. I'm just mentioning this for reference in case 
you want the ARM implementation to be closer to another arch which is also 
based on the device tree.

Thiago Jung Bauermann
IBM Linux Technology Center

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