4 EINJ provides a hardware error injection mechanism
5 It is very useful for debugging and testing of other APEI and RAS features.
7 To use EINJ, make sure the following are enabled in your kernel
14 The user interface of EINJ is debug file system, under the
15 directory apei/einj. The following files are provided.
17 - available_error_type
18 Reading this file returns the error injection capability of the
19 platform, that is, which error types are supported. The error type
20 definition is as follow, the left field is the error type value, the
21 right field is error description.
23 0x00000001 Processor Correctable
24 0x00000002 Processor Uncorrectable non-fatal
25 0x00000004 Processor Uncorrectable fatal
26 0x00000008 Memory Correctable
27 0x00000010 Memory Uncorrectable non-fatal
28 0x00000020 Memory Uncorrectable fatal
29 0x00000040 PCI Express Correctable
30 0x00000080 PCI Express Uncorrectable fatal
31 0x00000100 PCI Express Uncorrectable non-fatal
32 0x00000200 Platform Correctable
33 0x00000400 Platform Uncorrectable non-fatal
34 0x00000800 Platform Uncorrectable fatal
36 The format of file contents are as above, except there are only the
37 available error type lines.
40 This file is used to set the error type value. The error type value
41 is defined in "available_error_type" description.
44 Write any integer to this file to trigger the error
45 injection. Before this, please specify all necessary error
49 This file is used to set the first error parameter value. Effect of
50 parameter depends on error_type specified. For example, if error
51 type is memory related type, the param1 should be a valid physical
55 This file is used to set the second error parameter value. Effect of
56 parameter depends on error_type specified. For example, if error
57 type is memory related type, the param2 should be a physical memory
58 address mask. Linux requires page or narrower granularity, say,
62 The EINJ mechanism is a two step process. First inject the error, then
63 perform some actions to trigger it. Setting "notrigger" to 1 skips the
64 trigger phase, which *may* allow the user to cause the error in some other
65 context by a simple access to the cpu, memory location, or device that is
66 the target of the error injection. Whether this actually works depends
67 on what operations the BIOS actually includes in the trigger phase.
69 BIOS versions based in the ACPI 4.0 specification have limited options
70 to control where the errors are injected. Your BIOS may support an
71 extension (enabled with the param_extension=1 module parameter, or
72 boot command line einj.param_extension=1). This allows the address
73 and mask for memory injections to be specified by the param1 and
74 param2 files in apei/einj.
76 BIOS versions using the ACPI 5.0 specification have more control over
77 the target of the injection. For processor related errors (type 0x1,
78 0x2 and 0x4) the APICID of the target should be provided using the
79 param1 file in apei/einj. For memory errors (type 0x8, 0x10 and 0x20)
80 the address is set using param1 with a mask in param2 (0x0 is equivalent
81 to all ones). For PCI express errors (type 0x40, 0x80 and 0x100) the
82 segment, bus, device and function are specified using param1:
84 31 24 23 16 15 11 10 8 7 0
85 +-------------------------------------------------+
86 | segment | bus | device | function | reserved |
87 +-------------------------------------------------+
89 An ACPI 5.0 BIOS may also allow vendor specific errors to be injected.
90 In this case a file named vendor will contain identifying information
91 from the BIOS that hopefully will allow an application wishing to use
92 the vendor specific extension to tell that they are running on a BIOS
93 that supports it. All vendor extensions have the 0x80000000 bit set in
94 error_type. A file vendor_flags controls the interpretation of param1
95 and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor
96 documentation for details (and expect changes to this API if vendors
97 creativity in using this feature expands beyond our expectations).
100 # cd /sys/kernel/debug/apei/einj
101 # cat available_error_type # See which errors can be injected
102 0x00000002 Processor Uncorrectable non-fatal
103 0x00000008 Memory Correctable
104 0x00000010 Memory Uncorrectable non-fatal
105 # echo 0x12345000 > param1 # Set memory address for injection
106 # echo 0xfffffffffffff000 > param2 # Mask - anywhere in this page
107 # echo 0x8 > error_type # Choose correctable memory error
108 # echo 1 > error_inject # Inject now
111 For more information about EINJ, please refer to ACPI specification
112 version 4.0, section 17.5 and ACPI 5.0, section 18.6.