[PATCH v30 11/11] Documentation: dt: chosen properties for arm64 kdump
From: AKASHI Takahiro <hidden>
Date: 2017-01-24 08:53:20
Also in:
kexec, linux-devicetree
Subsystem:
open firmware and flattened device tree bindings, the rest · Maintainers:
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
From: James Morse <james.morse@arm.com> Add documentation for DT properties: linux,usable-memory-range linux,elfcorehdr used by arm64 kdump. Those decribe the usable memory range for crash dump kernel and the elfcorehdr's location within it, respectively. Signed-off-by: James Morse <james.morse@arm.com> [takahiro.akashi at linaro.org: added "linux,crashkernel-base" and "-size" ] Signed-off-by: AKASHI Takahiro <redacted> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: devicetree at vger.kernel.org Cc: Rob Herring <robh+dt@kernel.org> --- Documentation/devicetree/bindings/chosen.txt | 37 ++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+)
diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt
index 6ae9d82d4c37..8dc82431acc1 100644
--- a/Documentation/devicetree/bindings/chosen.txt
+++ b/Documentation/devicetree/bindings/chosen.txt@@ -52,3 +52,40 @@ 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,usable-memory-range +------------------------- + +This property (arm64 only) holds a base address and size, describing a +limited region in which memory may be considered available for use by +the kernel. Memory outside of this range is not available for use. + +This property describes a limitation: memory within this range is only +valid when also described through another mechanism that the kernel +would otherwise use to determine available memory (e.g. memory nodes +or the EFI memory map). Valid memory may be sparse within the range. +e.g. + +/ { + chosen { + linux,usable-memory-range = <0x9 0xf0000000 0x0 0x10000000>; + }; +}; + +The main usage is for crash dump kernel to identify its own usable +memory and exclude, at its boot time, any other memory areas that are +part of the panicked kernel's memory. + +linux,elfcorehdr +---------------- + +This property (currently used only on arm64) holds the memory range, +the address and the size, of the elf core header which mainly describes +the panicked kernel's memory layout as PT_LOAD segments of elf format. +e.g. + +/ { + chosen { + linux,elfcorehdr = <0x9 0xfffff000 0x0 0x800>; + }; +};
--
2.11.0