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authorFathi Boudra <fathi.boudra@linaro.org>2013-04-28 09:33:08 +0300
committerFathi Boudra <fathi.boudra@linaro.org>2013-04-28 09:33:08 +0300
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treeb9996006addfd7ae70a39672b76843b49aebc189 /Documentation/acpi/apei/einj.txt
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+ APEI Error INJection
+ ~~~~~~~~~~~~~~~~~~~~
+
+EINJ provides a hardware error injection mechanism
+It is very useful for debugging and testing of other APEI and RAS features.
+
+To use EINJ, make sure the following are enabled in your kernel
+configuration:
+
+CONFIG_DEBUG_FS
+CONFIG_ACPI_APEI
+CONFIG_ACPI_APEI_EINJ
+
+The user interface of EINJ is debug file system, under the
+directory apei/einj. The following files are provided.
+
+- available_error_type
+ Reading this file returns the error injection capability of the
+ platform, that is, which error types are supported. The error type
+ definition is as follow, the left field is the error type value, the
+ right field is error description.
+
+ 0x00000001 Processor Correctable
+ 0x00000002 Processor Uncorrectable non-fatal
+ 0x00000004 Processor Uncorrectable fatal
+ 0x00000008 Memory Correctable
+ 0x00000010 Memory Uncorrectable non-fatal
+ 0x00000020 Memory Uncorrectable fatal
+ 0x00000040 PCI Express Correctable
+ 0x00000080 PCI Express Uncorrectable fatal
+ 0x00000100 PCI Express Uncorrectable non-fatal
+ 0x00000200 Platform Correctable
+ 0x00000400 Platform Uncorrectable non-fatal
+ 0x00000800 Platform Uncorrectable fatal
+
+ The format of file contents are as above, except there are only the
+ available error type lines.
+
+- error_type
+ This file is used to set the error type value. The error type value
+ is defined in "available_error_type" description.
+
+- error_inject
+ Write any integer to this file to trigger the error
+ injection. Before this, please specify all necessary error
+ parameters.
+
+- param1
+ This file is used to set the first error parameter value. Effect of
+ parameter depends on error_type specified.
+
+- param2
+ This file is used to set the second error parameter value. Effect of
+ parameter depends on error_type specified.
+
+- notrigger
+ The EINJ mechanism is a two step process. First inject the error, then
+ perform some actions to trigger it. Setting "notrigger" to 1 skips the
+ trigger phase, which *may* allow the user to cause the error in some other
+ context by a simple access to the cpu, memory location, or device that is
+ the target of the error injection. Whether this actually works depends
+ on what operations the BIOS actually includes in the trigger phase.
+
+BIOS versions based in the ACPI 4.0 specification have limited options
+to control where the errors are injected. Your BIOS may support an
+extension (enabled with the param_extension=1 module parameter, or
+boot command line einj.param_extension=1). This allows the address
+and mask for memory injections to be specified by the param1 and
+param2 files in apei/einj.
+
+BIOS versions using the ACPI 5.0 specification have more control over
+the target of the injection. For processor related errors (type 0x1,
+0x2 and 0x4) the APICID of the target should be provided using the
+param1 file in apei/einj. For memory errors (type 0x8, 0x10 and 0x20)
+the address is set using param1 with a mask in param2 (0x0 is equivalent
+to all ones). For PCI express errors (type 0x40, 0x80 and 0x100) the
+segment, bus, device and function are specified using param1:
+
+ 31 24 23 16 15 11 10 8 7 0
+ +-------------------------------------------------+
+ | segment | bus | device | function | reserved |
+ +-------------------------------------------------+
+
+An ACPI 5.0 BIOS may also allow vendor specific errors to be injected.
+In this case a file named vendor will contain identifying information
+from the BIOS that hopefully will allow an application wishing to use
+the vendor specific extension to tell that they are running on a BIOS
+that supports it. All vendor extensions have the 0x80000000 bit set in
+error_type. A file vendor_flags controls the interpretation of param1
+and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor
+documentation for details (and expect changes to this API if vendors
+creativity in using this feature expands beyond our expectations).
+
+Example:
+# cd /sys/kernel/debug/apei/einj
+# cat available_error_type # See which errors can be injected
+0x00000002 Processor Uncorrectable non-fatal
+0x00000008 Memory Correctable
+0x00000010 Memory Uncorrectable non-fatal
+# echo 0x12345000 > param1 # Set memory address for injection
+# echo 0xfffffffffffff000 > param2 # Mask - anywhere in this page
+# echo 0x8 > error_type # Choose correctable memory error
+# echo 1 > error_inject # Inject now
+
+
+For more information about EINJ, please refer to ACPI specification
+version 4.0, section 17.5 and ACPI 5.0, section 18.6.