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From: takahiro.akashi@linaro.org (AKASHI Takahiro)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v35 13/14] Documentation: dt: chosen properties for arm64 kdump
Date: Mon,  3 Apr 2017 11:26:06 +0900	[thread overview]
Message-ID: <20170403022606.12609-1-takahiro.akashi@linaro.org> (raw)
In-Reply-To: <20170403022139.12383-1-takahiro.akashi@linaro.org>

From: James Morse <james.morse@arm.com>

Add documentation for DT properties:
	linux,usable-memory-range
	linux,elfcorehdr
used by arm64 kdump. Those are, respectively, a usable memory range
allocated to crash dump kernel and the elfcorehdr's location within it.

Signed-off-by: James Morse <james.morse@arm.com>
[takahiro.akashi at linaro.org: update the text due to recent changes ]
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
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 | 45 ++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt
index 6ae9d82d4c37..b5e39af4ddc0 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,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.
+
+While this property does not represent a real hardware, the address
+and the size are expressed in #address-cells and #size-cells,
+respectively, of the root node.
+
+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>;
+	};
+};
+
+While this property does not represent a real hardware, the address
+and the size are expressed in #address-cells and #size-cells,
+respectively, of the root node.
-- 
2.11.1

  parent reply	other threads:[~2017-04-03  2:26 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-03  2:21 [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro
2017-04-03  2:23 ` [PATCH v35 01/14] memblock: add memblock_clear_nomap() AKASHI Takahiro
2017-04-03  2:23 ` [PATCH v35 02/14] memblock: add memblock_cap_memory_range() AKASHI Takahiro
2017-04-05 17:20   ` Catalin Marinas
2017-04-03  2:24 ` [PATCH v35 03/14] arm64: limit memory regions based on DT property, usable-memory-range AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 04/14] arm64: kdump: reserve memory for crash dump kernel AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 05/14] arm64: mm: add set_memory_valid() AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 06/14] arm64: kdump: protect crash dump kernel memory AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 07/14] arm64: hibernate: preserve kdump image around hibernation AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 08/14] arm64: kdump: implement machine_crash_shutdown() AKASHI Takahiro
2017-04-03  9:21   ` David Woodhouse
2017-04-04  7:29     ` AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 09/14] arm64: kdump: add VMCOREINFO's for user-space tools AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 10/14] arm64: kdump: provide /proc/vmcore file AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 11/14] arm64: kdump: enable kdump in defconfig AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 12/14] Documentation: kdump: describe arm64 port AKASHI Takahiro
2017-04-03  2:26 ` AKASHI Takahiro [this message]
2017-04-03  2:26 ` [PATCH v35 14/14] efi/libstub/arm*: Set default address and size cells values for an empty dtb AKASHI Takahiro
2017-05-22  0:25 ` [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro

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