1 # SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/reserved-memory/ramoops.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: Ramoops oops/panic logger
8
9 description: |
10 ramoops provides persistent RAM storage for oops and panics, so they can be
11 recovered after a reboot. This is a child-node of "/reserved-memory", and
12 is named "ramoops" after the backend, rather than "pstore" which is the
13 subsystem.
14
15 Parts of this storage may be set aside for other persistent log buffers, such
16 as kernel log messages, or for optional ECC error-correction data. The total
17 size of these optional buffers must fit in the reserved region.
18
19 Any remaining space will be used for a circular buffer of oops and panic
20 records. These records have a configurable size, with a size of 0 indicating
21 that they should be disabled.
22
23 At least one of "record-size", "console-size", "ftrace-size", or "pmsg-size"
24 must be set non-zero, but are otherwise optional as listed below.
25
26 maintainers:
27 - Kees Cook <keescook@chromium.org>
28
29 allOf:
30 - $ref: reserved-memory.yaml
31
32 properties:
33 compatible:
34 const: ramoops
35
36 reg:
37 description: region of memory that is preserved between reboots
38
39 ecc-size:
40 $ref: /schemas/types.yaml#/definitions/uint32
41 description: enables ECC support and specifies ECC buffer size in bytes
42 default: 0 # no ECC
43
44 record-size:
45 $ref: /schemas/types.yaml#/definitions/uint32
46 description: maximum size in bytes of each kmsg dump
47 default: 0
48
49 console-size:
50 $ref: /schemas/types.yaml#/definitions/uint32
51 description: size in bytes of log buffer reserved for kernel messages
52 default: 0
53
54 ftrace-size:
55 $ref: /schemas/types.yaml#/definitions/uint32
56 description: size in bytes of log buffer reserved for function tracing and profiling
57 default: 0
58
59 pmsg-size:
60 $ref: /schemas/types.yaml#/definitions/uint32
61 description: size in bytes of log buffer reserved for userspace messages
62 default: 0
63
64 mem-type:
65 $ref: /schemas/types.yaml#/definitions/uint32
66 description: if present, sets the type of mapping is to be used to map the reserved region.
67 default: 0
68 oneOf:
69 - const: 0
70 description: write-combined
71 - const: 1
72 description: unbuffered
73 - const: 2
74 description: cached
75
76 max-reason:
77 $ref: /schemas/types.yaml#/definitions/uint32
78 default: 2 # log oopses and panics
79 maximum: 0x7fffffff
80 description: |
81 If present, sets maximum type of kmsg dump reasons to store.
82 This can be set to INT_MAX to store all kmsg dumps.
83 See include/linux/kmsg_dump.h KMSG_DUMP_* for other kmsg dump reason values.
84 Setting this to 0 (KMSG_DUMP_UNDEF), means the reason filtering will be
85 controlled by the printk.always_kmsg_dump boot param.
86 If unset, it will be 2 (KMSG_DUMP_OOPS), otherwise 5 (KMSG_DUMP_MAX).
87
88 flags:
89 $ref: /schemas/types.yaml#/definitions/uint32
90 default: 0
91 description: |
92 If present, pass ramoops behavioral flags
93 (see include/linux/pstore_ram.h RAMOOPS_FLAG_* for flag values).
94
95 no-dump-oops:
96 deprecated: true
97 type: boolean
98 description: |
99 Use max_reason instead. If present, and max_reason is not specified,
100 it is equivalent to max_reason = 1 (KMSG_DUMP_PANIC).
101
102 unbuffered:
103 deprecated: true
104 type: boolean
105 description: |
106 Use mem_type instead. If present, and mem_type is not specified,
107 it is equivalent to mem_type = 1 and uses unbuffered mappings to map
108 the reserved region (defaults to buffered mappings mem_type = 0).
109 If both are specified -- "mem_type" overrides "unbuffered".
110
111 unevaluatedProperties: false
112
113 required:
114 - compatible
115 - reg
116
117 anyOf:
118 - required: [record-size]
119 - required: [console-size]
120 - required: [ftrace-size]
121 - required: [pmsg-size]
122
123 examples:
124 - |
125 / {
126 compatible = "foo";
127 model = "foo";
128 #address-cells = <1>;
129 #size-cells = <1>;
130
131 reserved-memory {
132 #address-cells = <1>;
133 #size-cells = <1>;
134 ranges;
135
136 ramoops@bfdf0000 {
137 compatible = "ramoops";
138 reg = <0xbfdf0000 0x10000>; /* 64kB */
139 console-size = <0x8000>; /* 32kB */
140 record-size = <0x400>; /* 1kB */
141 ecc-size = <16>;
142 };
143 };
144 };
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TOMOYO® is a registered trademark of NTT DATA CORPORATION.