Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
kho/abi: add memblock ABI header
Introduce KHO ABI header describing preservation ABI for memblock's
reserve_mem regions and link the relevant documentation to KHO docs.
[lukas.bulwahn@redhat.com: MAINTAINERS: adjust file entry in MEMBLOCK AND MEMORY MANAGEMENT INITIALIZATION]
Link: https://lkml.kernel.org/r/20260107090438.22901-1-lukas.bulwahn@redhat.com
[rppt@kernel.org: update reserved_mem node description, per Pratyush]
Link: https://lkml.kernel.org/r/aW_M-HYZzx5SkbnZ@kernel.org
Link: https://lkml.kernel.org/r/20260105165839.285270-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Jason Miu <jasonmiu@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
authored by
Mike Rapoport (Microsoft)
and committed by
Andrew Morton
dd1e79ef
ac2d8102
+81
-83
+6
Documentation/core-api/kho/abi.rst
+6
Documentation/core-api/kho/abi.rst
···
16
16
.. kernel-doc:: include/linux/kho/abi/kexec_handover.h
17
17
:doc: Kexec Handover ABI for vmalloc Preservation
18
18
19
+
memblock preservation ABI
20
+
=========================
21
+
22
+
.. kernel-doc:: include/linux/kho/abi/memblock.h
23
+
:doc: memblock kexec handover ABI
24
+
19
25
See Also
20
26
========
21
27
-39
Documentation/core-api/kho/bindings/memblock/memblock.yaml
-39
Documentation/core-api/kho/bindings/memblock/memblock.yaml
···
1
-
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2
-
%YAML 1.2
3
-
---
4
-
title: Memblock reserved memory
5
-
6
-
maintainers:
7
-
- Mike Rapoport <rppt@kernel.org>
8
-
9
-
description: |
10
-
Memblock can serialize its current memory reservations created with
11
-
reserve_mem command line option across kexec through KHO.
12
-
The post-KHO kernel can then consume these reservations and they are
13
-
guaranteed to have the same physical address.
14
-
15
-
properties:
16
-
compatible:
17
-
enum:
18
-
- reserve-mem-v1
19
-
20
-
patternProperties:
21
-
"$[0-9a-f_]+^":
22
-
$ref: reserve-mem.yaml#
23
-
description: reserved memory regions
24
-
25
-
required:
26
-
- compatible
27
-
28
-
additionalProperties: false
29
-
30
-
examples:
31
-
- |
32
-
memblock {
33
-
compatible = "memblock-v1";
34
-
n1 {
35
-
compatible = "reserve-mem-v1";
36
-
start = <0xc06b 0x4000000>;
37
-
size = <0x04 0x00>;
38
-
};
39
-
};
-40
Documentation/core-api/kho/bindings/memblock/reserve-mem.yaml
-40
Documentation/core-api/kho/bindings/memblock/reserve-mem.yaml
···
1
-
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2
-
%YAML 1.2
3
-
---
4
-
title: Memblock reserved memory regions
5
-
6
-
maintainers:
7
-
- Mike Rapoport <rppt@kernel.org>
8
-
9
-
description: |
10
-
Memblock can serialize its current memory reservations created with
11
-
reserve_mem command line option across kexec through KHO.
12
-
This object describes each such region.
13
-
14
-
properties:
15
-
compatible:
16
-
enum:
17
-
- reserve-mem-v1
18
-
19
-
start:
20
-
description: |
21
-
physical address (u64) of the reserved memory region.
22
-
23
-
size:
24
-
description: |
25
-
size (u64) of the reserved memory region.
26
-
27
-
required:
28
-
- compatible
29
-
- start
30
-
- size
31
-
32
-
additionalProperties: false
33
-
34
-
examples:
35
-
- |
36
-
n1 {
37
-
compatible = "reserve-mem-v1";
38
-
start = <0xc06b 0x4000000>;
39
-
size = <0x04 0x00>;
40
-
};
+1
-1
MAINTAINERS
+1
-1
MAINTAINERS
···
16396
16396
T: git git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock.git for-next
16397
16397
T: git git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock.git fixes
16398
16398
F: Documentation/core-api/boot-time-mm.rst
16399
-
F: Documentation/core-api/kho/bindings/memblock/*
16399
+
F: include/linux/kho/abi/memblock.h
16400
16400
F: include/linux/memblock.h
16401
16401
F: mm/bootmem_info.c
16402
16402
F: mm/memblock.c
+73
include/linux/kho/abi/memblock.h
+73
include/linux/kho/abi/memblock.h
···
1
+
/* SPDX-License-Identifier: GPL-2.0 */
2
+
3
+
#ifndef _LINUX_KHO_ABI_MEMBLOCK_H
4
+
#define _LINUX_KHO_ABI_MEMBLOCK_H
5
+
6
+
/**
7
+
* DOC: memblock kexec handover ABI
8
+
*
9
+
* Memblock can serialize its current memory reservations created with
10
+
* reserve_mem command line option across kexec through KHO.
11
+
* The post-KHO kernel can then consume these reservations and they are
12
+
* guaranteed to have the same physical address.
13
+
*
14
+
* The state is serialized using Flattened Device Tree (FDT) format. Any
15
+
* modification to the FDT structure, node properties, or the compatible
16
+
* strings constitutes a breaking change. Such changes require incrementing the
17
+
* version number in the relevant `_COMPATIBLE` string to prevent a new kernel
18
+
* from misinterpreting data from an old kernel.
19
+
*
20
+
* Changes are allowed provided the compatibility version is incremented.
21
+
* However, backward/forward compatibility is only guaranteed for kernels
22
+
* supporting the same ABI version.
23
+
*
24
+
* FDT Structure Overview:
25
+
* The entire memblock state is encapsulated within a single KHO entry named
26
+
* "memblock".
27
+
* This entry contains an FDT with the following layout:
28
+
*
29
+
* .. code-block:: none
30
+
*
31
+
* / {
32
+
* compatible = "memblock-v1";
33
+
*
34
+
* n1 {
35
+
* compatible = "reserve-mem-v1";
36
+
* start = <0xc06b 0x4000000>;
37
+
* size = <0x04 0x00>;
38
+
* };
39
+
* };
40
+
*
41
+
* Main memblock node (/):
42
+
*
43
+
* - compatible: "memblock-v1"
44
+
45
+
* Identifies the overall memblock ABI version.
46
+
*
47
+
* reserved_mem node:
48
+
* These nodes describe all reserve_mem regions. The node name is the name
49
+
* defined by the user for a reserve_mem region.
50
+
*
51
+
* - compatible: "reserve-mem-v1"
52
+
*
53
+
* Identifies the ABI version of reserve_mem descriptions
54
+
*
55
+
* - start: u64
56
+
*
57
+
* Physical address of the reserved memory region.
58
+
*
59
+
* - size: u64
60
+
*
61
+
* size in bytes of the reserved memory region.
62
+
*/
63
+
64
+
/* Top level memblock FDT node name. */
65
+
#define MEMBLOCK_KHO_FDT "memblock"
66
+
67
+
/* The compatible string for the memblock FDT root node. */
68
+
#define MEMBLOCK_KHO_NODE_COMPATIBLE "memblock-v1"
69
+
70
+
/* The compatible string for the reserve_mem FDT nodes. */
71
+
#define RESERVE_MEM_KHO_NODE_COMPATIBLE "reserve-mem-v1"
72
+
73
+
#endif /* _LINUX_KHO_ABI_MEMBLOCK_H */
+1
-3
mm/memblock.c
+1
-3
mm/memblock.c
···
21
21
#ifdef CONFIG_KEXEC_HANDOVER
22
22
#include <linux/libfdt.h>
23
23
#include <linux/kexec_handover.h>
24
+
#include <linux/kho/abi/memblock.h>
24
25
#endif /* CONFIG_KEXEC_HANDOVER */
25
26
26
27
#include <asm/sections.h>
···
2443
2442
}
2444
2443
2445
2444
#ifdef CONFIG_KEXEC_HANDOVER
2446
-
#define MEMBLOCK_KHO_FDT "memblock"
2447
-
#define MEMBLOCK_KHO_NODE_COMPATIBLE "memblock-v1"
2448
-
#define RESERVE_MEM_KHO_NODE_COMPATIBLE "reserve-mem-v1"
2449
2445
2450
2446
static int __init reserved_mem_preserve(void)
2451
2447
{