From: James Morse <james.morse@xxxxxxx>
Add documentation for
linux,crashkernel-base and crashkernel-size,
linux,usable-memory-range
linux,elfcorehdr
used by arm64 kdump to decribe the kdump reserved area, and
the elfcorehdr's location within it.
Signed-off-by: James Morse <james.morse@xxxxxxx>
[takahiro.akashi@xxxxxxxxxx: added "linux,crashkernel-base" and "-size" ]
Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
---
Documentation/devicetree/bindings/chosen.txt | 50 ++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt
index 6ae9d82d4c37..7b115165e9ec 100644
--- a/Documentation/devicetree/bindings/chosen.txt
+++ b/Documentation/devicetree/bindings/chosen.txt
@@ -52,3 +52,53 @@ 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 (currently used on PowerPC and arm64) indicates
+the base address and the size, respectively, of the reserved memory
+range for crash dump kernel.
+e.g.
+
+/ {
+ chosen {
+ linux,crashkernel-base = <0x9 0xf0000000>;
+ linux,crashkernel-size = <0x0 0x10000000>;
+ };
+};
+
+linux,usable-memory-range
+-------------------------
+
+This property (currently used only on arm64) holds the memory range,
+the base address and the size, which can be used as system ram on
+the *current* kernel. Note that, if this property is present, any memory
+regions under "memory" nodes in DT blob or ones marked as "conventional
+memory" in EFI memory map should be ignored.
+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
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