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# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/reserved-memory/ramoops.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Ramoops oops/panic logger
description: |
ramoops provides persistent RAM storage for oops and panics, so they can be
recovered after a reboot. This is a child-node of "/reserved-memory", and
is named "ramoops" after the backend, rather than "pstore" which is the
subsystem.
Parts of this storage may be set aside for other persistent log buffers, such
as kernel log messages, or for optional ECC error-correction data. The total
size of these optional buffers must fit in the reserved region.
Any remaining space will be used for a circular buffer of oops and panic
records. These records have a configurable size, with a size of 0 indicating
that they should be disabled.
At least one of "record-size", "console-size", "ftrace-size", or "pmsg-size"
must be set non-zero, but are otherwise optional as listed below.
maintainers:
- Kees Cook <keescook@chromium.org>
allOf:
- $ref: reserved-memory.yaml
properties:
compatible:
const: ramoops
reg:
description: region of memory that is preserved between reboots
ecc-size:
$ref: /schemas/types.yaml#/definitions/uint32
description: enables ECC support and specifies ECC buffer size in bytes
default: 0 # no ECC
record-size:
$ref: /schemas/types.yaml#/definitions/uint32
description: maximum size in bytes of each kmsg dump
default: 0
console-size:
$ref: /schemas/types.yaml#/definitions/uint32
description: size in bytes of log buffer reserved for kernel messages
default: 0
ftrace-size:
$ref: /schemas/types.yaml#/definitions/uint32
description: size in bytes of log buffer reserved for function tracing and profiling
default: 0
pmsg-size:
$ref: /schemas/types.yaml#/definitions/uint32
description: size in bytes of log buffer reserved for userspace messages
default: 0
mem-type:
$ref: /schemas/types.yaml#/definitions/uint32
description: if present, sets the type of mapping is to be used to map the reserved region.
default: 0
oneOf:
- const: 0
description: write-combined
- const: 1
description: unbuffered
- const: 2
description: cached
max-reason:
$ref: /schemas/types.yaml#/definitions/uint32
default: 2 # log oopses and panics
maximum: 0x7fffffff
description: |
If present, sets maximum type of kmsg dump reasons to store.
This can be set to INT_MAX to store all kmsg dumps.
See include/linux/kmsg_dump.h KMSG_DUMP_* for other kmsg dump reason values.
Setting this to 0 (KMSG_DUMP_UNDEF), means the reason filtering will be
controlled by the printk.always_kmsg_dump boot param.
If unset, it will be 2 (KMSG_DUMP_OOPS), otherwise 5 (KMSG_DUMP_MAX).
flags:
$ref: /schemas/types.yaml#/definitions/uint32
default: 0
description: |
If present, pass ramoops behavioral flags
(see include/linux/pstore_ram.h RAMOOPS_FLAG_* for flag values).
no-dump-oops:
deprecated: true
type: boolean
description: |
Use max_reason instead. If present, and max_reason is not specified,
it is equivalent to max_reason = 1 (KMSG_DUMP_PANIC).
unbuffered:
deprecated: true
type: boolean
description: |
Use mem_type instead. If present, and mem_type is not specified,
it is equivalent to mem_type = 1 and uses unbuffered mappings to map
the reserved region (defaults to buffered mappings mem_type = 0).
If both are specified -- "mem_type" overrides "unbuffered".
unevaluatedProperties: false
required:
- compatible
- reg
anyOf:
- required: [record-size]
- required: [console-size]
- required: [ftrace-size]
- required: [pmsg-size]
examples:
- |
/ {
compatible = "foo";
model = "foo";
#address-cells = <1>;
#size-cells = <1>;
reserved-memory {
#address-cells = <1>;
#size-cells = <1>;
ranges;
ramoops@bfdf0000 {
compatible = "ramoops";
reg = <0xbfdf0000 0x10000>; /* 64kB */
console-size = <0x8000>; /* 32kB */
record-size = <0x400>; /* 1kB */
ecc-size = <16>;
};
};
};
|
