On Tue, Jul 26, 2016 at 05:02:06PM +0900, AKASHI Takahiro wrote:
> From: James Morse <[email protected]>
>
> Add documentation for
> linux,crashkernel-base and crashkernel-size,
> linux,usable-memory-range, and
> linux,elfcorehdr
> used by arm64 kexec/kdump to decribe the kdump reserved area, and
> the elfcorehdr's location within it.
>
> Signed-off-by: James Morse <[email protected]>
> [[email protected]:
> renamed "usable-memory" to "usable-memory-range",
> added "linux,crashkernel-base" and "-size" ]
> Signed-off-by: AKASHI Takahiro <[email protected]>
> ---
> Documentation/devicetree/bindings/chosen.txt | 45
> ++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/chosen.txt
> b/Documentation/devicetree/bindings/chosen.txt
> index 6ae9d82..d7a3a86 100644
> --- a/Documentation/devicetree/bindings/chosen.txt
> +++ b/Documentation/devicetree/bindings/chosen.txt
> @@ -52,3 +52,48 @@ This property is set (currently only on PowerPC, and only
> needed on
> book3e) by some versions of kexec-tools to tell the new kernel that it
> is being booted by kexec, as the booting environment may differ (e.g.
> a different secondary CPU release mechanism)
> +
> +linux,crashkernel-base
> +linux,crashkernel-size
> +----------------------
> +These properties are set (on PowerPC and arm64) during kdump to tell
> +use-space tools, like kexec-tools, the base address of the crash-dump
s/use/user/
Ideally, userspace should not care whether this comes from DT, kernel
command-line or somewhere else and should be exposed in some source
independent way. However, that's not really the problem for the binding.
> +kernel's reserved area of memory and the size. e.g.
> +
> +/ {
> + chosen {
> + linux,crashkernel-base = <0x9 0xf0000000>;
> + linux,crashkernel-size = <0x0 0x10000000>;
> + };
> +};
> +
> +linux,usable-memory-range
> +-------------------------
> +
> +This property is set (currently only on arm64) during kdump to tell
> +the crash-dump kernel the base address of its reserved area of memory,
> +and the size. e.g.
> +
> +/ {
> + chosen {
> + linux,usable-memory-range = <0x9 0xf0000000 0x0 0x10000000>;
This is the same range as linux,crashkernel-*, but used by the 2nd
kernel? Why not just update the memory node or use command line mem=
parameter?
Why has PPC not need this and ARM does?
> + };
> +};
> +
> +Please note that, if this property is present, any memory regions under
> +"memory" nodes will be ignored.
> +
> +linux,elfcorehdr
> +----------------
> +
> +This property is set (currently only on arm64) during kdump to tell
> +the crash-dump kernel the address and size of the elfcorehdr that describes
> +the old kernel's memory as an elf file. This memory must reside within
> +the area described by 'linux,usable-memory-range'. e.g.
> +
> +/ {
> + chosen {
> + linux,usable-memory = <0x9 0xf0000000 0x0 0x10000000>;
> + linux,elfcorehdr = <0x9 0xfffff000 0x0 0x800>;
> + };
> +};
> --
> 2.9.0
>
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