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Documentation / acpi / apei / einj.txt




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Based on kernel version 3.15.4. Page generated on 2014-07-07 08:59 EST.

1				APEI Error INJection
2				~~~~~~~~~~~~~~~~~~~~
3	
4	EINJ provides a hardware error injection mechanism
5	It is very useful for debugging and testing of other APEI and RAS features.
6	
7	To use EINJ, make sure the following are enabled in your kernel
8	configuration:
9	
10	CONFIG_DEBUG_FS
11	CONFIG_ACPI_APEI
12	CONFIG_ACPI_APEI_EINJ
13	
14	The user interface of EINJ is debug file system, under the
15	directory apei/einj. The following files are provided.
16	
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.
22	
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
35	
36	  The format of file contents are as above, except there are only the
37	  available error type lines.
38	
39	- error_type
40	  This file is used to set the error type value. The error type value
41	  is defined in "available_error_type" description.
42	
43	- error_inject
44	  Write any integer to this file to trigger the error
45	  injection. Before this, please specify all necessary error
46	  parameters.
47	
48	- flags
49	  Present for kernel version 3.13 and above. Used to specify which
50	  of param{1..4} are valid and should be used by BIOS during injection.
51	  Value is a bitmask as specified in ACPI5.0 spec for the
52	  SET_ERROR_TYPE_WITH_ADDRESS data structure:
53		Bit 0 - Processor APIC field valid (see param3 below)
54		Bit 1 - Memory address and mask valid (param1 and param2)
55		Bit 2 - PCIe (seg,bus,dev,fn) valid (param4 below)
56	  If set to zero, legacy behaviour is used where the type of injection
57	  specifies just one bit set, and param1 is multiplexed.
58	
59	- param1
60	  This file is used to set the first error parameter value. Effect of
61	  parameter depends on error_type specified. For example, if error
62	  type is memory related type, the param1 should be a valid physical
63	  memory address. [Unless "flag" is set - see above]
64	
65	- param2
66	  This file is used to set the second error parameter value. Effect of
67	  parameter depends on error_type specified. For example, if error
68	  type is memory related type, the param2 should be a physical memory
69	  address mask. Linux requires page or narrower granularity, say,
70	  0xfffffffffffff000.
71	
72	- param3
73	  Used when the 0x1 bit is set in "flag" to specify the APIC id
74	
75	- param4
76	  Used when the 0x4 bit is set in "flag" to specify target PCIe device
77	
78	- notrigger
79	  The EINJ mechanism is a two step process. First inject the error, then
80	  perform some actions to trigger it. Setting "notrigger" to 1 skips the
81	  trigger phase, which *may* allow the user to cause the error in some other
82	  context by a simple access to the cpu, memory location, or device that is
83	  the target of the error injection. Whether this actually works depends
84	  on what operations the BIOS actually includes in the trigger phase.
85	
86	BIOS versions based in the ACPI 4.0 specification have limited options
87	to control where the errors are injected.  Your BIOS may support an
88	extension (enabled with the param_extension=1 module parameter, or
89	boot command line einj.param_extension=1). This allows the address
90	and mask for memory injections to be specified by the param1 and
91	param2 files in apei/einj.
92	
93	BIOS versions using the ACPI 5.0 specification have more control over
94	the target of the injection. For processor related errors (type 0x1,
95	0x2 and 0x4) the APICID of the target should be provided using the
96	param1 file in apei/einj. For memory errors (type 0x8, 0x10 and 0x20)
97	the address is set using param1 with a mask in param2 (0x0 is equivalent
98	to all ones). For PCI express errors (type 0x40, 0x80 and 0x100) the
99	segment, bus, device and function are specified using param1:
100	
101	         31     24 23    16 15    11 10      8  7        0
102		+-------------------------------------------------+
103		| segment |   bus  | device | function | reserved |
104		+-------------------------------------------------+
105	
106	An ACPI 5.0 BIOS may also allow vendor specific errors to be injected.
107	In this case a file named vendor will contain identifying information
108	from the BIOS that hopefully will allow an application wishing to use
109	the vendor specific extension to tell that they are running on a BIOS
110	that supports it. All vendor extensions have the 0x80000000 bit set in
111	error_type. A file vendor_flags controls the interpretation of param1
112	and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor
113	documentation for details (and expect changes to this API if vendors
114	creativity in using this feature expands beyond our expectations).
115	
116	Example:
117	# cd /sys/kernel/debug/apei/einj
118	# cat available_error_type		# See which errors can be injected
119	0x00000002	Processor Uncorrectable non-fatal
120	0x00000008	Memory Correctable
121	0x00000010	Memory Uncorrectable non-fatal
122	# echo 0x12345000 > param1		# Set memory address for injection
123	# echo 0xfffffffffffff000 > param2	# Mask - anywhere in this page
124	# echo 0x8 > error_type			# Choose correctable memory error
125	# echo 1 > error_inject			# Inject now
126	
127	
128	For more information about EINJ, please refer to ACPI specification
129	version 4.0, section 17.5 and ACPI 5.0, section 18.6.
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