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[v18,13/13] Documentation: dt: usable-memory and elfcorehdr nodes for arm64 kexec

Message ID a02229764b36469c739e39eeaf8809e96c4e1ff6.1465502767.git.geoff@infradead.org (mailing list archive)
State New, archived
Headers show

Commit Message

Geoff Levand June 9, 2016, 8:08 p.m. UTC 
From: James Morse <james.morse@arm.com>

Add documentation for linux,usable-memory and linux,elfcorehdr chosen nodes
used by arm64 kexec to decribe the kdump reserved area, and the elfcorehdr's
location within it.

Signed-off-by: James Morse <james.morse@arm.com>
---
 Documentation/devicetree/bindings/chosen.txt | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
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Patch

diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt
index 6ae9d82..443f88b 100644
--- a/Documentation/devicetree/bindings/chosen.txt
+++ b/Documentation/devicetree/bindings/chosen.txt
@@ -52,3 +52,31 @@  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
+-------------------
+
+This property is set on PowerPC and arm64 by kexec-tools during kdump
+to tell the crash kernel the base address of its reserved area of memory, and
+the size. e.g.
+
+/ {
+	chosen {
+		linux,usable-memory = <0x9 0xf0000000 0x0 0x10000000>;
+	};
+};
+
+linux,elfcorehdr
+----------------
+
+This property is set (currently only on arm64) by kexec-tools during kdump
+to tell the crash 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'. e.g.
+
+/ {
+	chosen {
+		linux,usable-memory = <0x9 0xf0000000 0x0 0x10000000>;
+		linux,elfcorehdr = <0x9 0xfffff000 0x0 0x800>;
+	};
+};