The patch titled
Subject: Documentation: KHO: add memblock bindings
has been added to the -mm mm-nonmm-unstable branch. Its filename is
documentation-kho-add-memblock-bindings.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/documentation-kho-add-memblock-bindings.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Mike Rapoport (Microsoft)" <rppt@xxxxxxxxxx>
Subject: Documentation: KHO: add memblock bindings
Date: Thu, 6 Feb 2025 15:27:54 +0200
We introduced KHO into Linux: A framework that allows Linux to pass
metadata and memory across kexec from Linux to Linux. KHO reuses fdt as
file format and shares a lot of the same properties of firmware-to- Linux
boot formats: It needs a stable, documented ABI that allows for forward
and backward compatibility as well as versioning.
As first user of KHO, we introduced memblock which can now preserve memory
ranges reserved with reserve_mem command line options contents across
kexec, so you can use the post-kexec kernel to read traces from the
pre-kexec kernel.
This patch adds memblock schemas similar to "device" device tree ones to a
new kho bindings directory. This allows us to force contributors to
document the data that moves across KHO kexecs and catch breaking change
during review.
Link: https://lkml.kernel.org/r/20250206132754.2596694-15-rppt@xxxxxxxxxx
Co-developed-by: Alexander Graf <graf@xxxxxxxxxx>
Signed-off-by: Alexander Graf <graf@xxxxxxxxxx>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Ashish Kalra <ashish.kalra@xxxxxxx>
Cc: Ben Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Betkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: James Gowans <jgowans@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Pratyush Yadav <ptyadav@xxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Saravana Kannan <saravanak@xxxxxxxxxx>
Cc: Stanislav Kinsburskii <skinsburskii@xxxxxxxxxxxxxxxxxxx>
Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Usama Arif <usama.arif@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/kho/bindings/memblock/reserve_mem.yaml | 41 +++++++++
Documentation/kho/bindings/memblock/reserve_mem_map.yaml | 42 ++++++++++
2 files changed, 83 insertions(+)
diff --git a/Documentation/kho/bindings/memblock/reserve_mem_map.yaml a/Documentation/kho/bindings/memblock/reserve_mem_map.yaml
new file mode 100644
--- /dev/null
+++ a/Documentation/kho/bindings/memblock/reserve_mem_map.yaml
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memblock/reserve_mem_map.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Memblock reserved memory regions
+
+maintainers:
+ - Mike Rapoport <rppt@xxxxxxxxxx>
+
+description: |
+ Memblock can serialize its current memory reservations created with
+ reserve_mem command line option across kexec through KHO.
+ This object describes each such region.
+
+properties:
+ compatible:
+ enum:
+ - reserve_mem_map-v1
+
+ mem:
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ description: |
+ Array of { u64 phys_addr, u64 len } elements that describe a list of
+ memory ranges.
+
+required:
+ - compatible
+ - mem
+
+additionalProperties: false
+
+examples:
+ - |
+ reserve_mem {
+ compatible = "reserve_mem-v1";
+ r1 {
+ compatible = "reserve_mem_map-v1";
+ mem = <0xc07c 0x2000000 0x01 0x00>;
+ };
+ };
diff --git a/Documentation/kho/bindings/memblock/reserve_mem.yaml a/Documentation/kho/bindings/memblock/reserve_mem.yaml
new file mode 100644
--- /dev/null
+++ a/Documentation/kho/bindings/memblock/reserve_mem.yaml
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/memblock/reserve_mem.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Memblock reserved memory
+
+maintainers:
+ - Mike Rapoport <rppt@xxxxxxxxxx>
+
+description: |
+ Memblock can serialize its current memory reservations created with
+ reserve_mem command line option across kexec through KHO.
+ The post-KHO kernel can then consume these reservations and they are
+ guaranteed to have the same physical address.
+
+properties:
+ compatible:
+ enum:
+ - reserve_mem-v1
+
+patternProperties:
+ "$[0-9a-f_]+^":
+ $ref: reserve_mem_map.yaml#
+ description: reserved memory regions
+
+required:
+ - compatible
+
+additionalProperties: false
+
+examples:
+ - |
+ reserve_mem {
+ compatible = "reserve_mem-v1";
+ r1 {
+ compatible = "reserve_mem_map-v1";
+ mem = <0xc07c 0x2000000 0x01 0x00>;
+ };
+ };
_
Patches currently in -mm which might be from rppt@xxxxxxxxxx are
mm-mm_init-rename-init_reserved_page-to-init_deferred_page.patch
memblock-add-memblock_rsrv_kern-flag.patch
memblock-introduce-memmap_init_kho_scratch.patch
x86-setup-use-memblock_reserve_kern-for-memory-used-by-kernel.patch
documentation-kho-add-memblock-bindings.patch
