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 7title: Ramoops oops/panic logger 8 9description: | 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 26maintainers: 27 - Kees Cook <keescook@chromium.org> 28 29allOf: 30 - $ref: reserved-memory.yaml 31 32properties: 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 111unevaluatedProperties: false 112 113required: 114 - compatible 115 - reg 116 117anyOf: 118 - required: [record-size] 119 - required: [console-size] 120 - required: [ftrace-size] 121 - required: [pmsg-size] 122 123examples: 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 }; 145