diff mbox

[v28,9/9] Documentation: dt: chosen properties for arm64 kdump

Message ID 20161124095944.7167-1-takahiro.akashi@linaro.org
State Superseded
Headers show

Commit Message

AKASHI Takahiro Nov. 24, 2016, 9:59 a.m. UTC 
From: James Morse <james.morse@arm.com>


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@arm.com>

[takahiro.akashi@linaro.org: added "linux,crashkernel-base" and "-size" ]
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

Cc: devicetree@vger.kernel.org
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
---
 Documentation/devicetree/bindings/chosen.txt | 50 ++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

-- 
2.10.0

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Comments

Catalin Marinas Nov. 24, 2016, 5:14 p.m. UTC | #1 
On Thu, Nov 24, 2016 at 06:59:44PM +0900, AKASHI Takahiro wrote:
> From: James Morse <james.morse@arm.com>

> 

> 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@arm.com>

> [takahiro.akashi@linaro.org: added "linux,crashkernel-base" and "-size" ]

> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

> Cc: devicetree@vger.kernel.org

> Cc: Rob Herring <robh+dt@kernel.org>

> Cc: Mark Rutland <mark.rutland@arm.com>


Rob, Mark, are you ok with this patch?

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Catalin
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diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt
index 6ae9d82..7b11516 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>;
+	};
+};