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When I added support for ACPI5 I made the assumption that injected processor errors would just need to know the APICID, memory errors just the address and mask, and PCIe errors just the segment/bus/device/function. So I had the code check the type of injection and multiplex the "param1" value appropriately. This was not a good assumption :-( There are injection scenarios where we need to specify more than one of these items. E.g. injecting a cache error we need to specify an APICID of the cpu that owns the cache, and also an address (so that we can trip the error by accessing the address). Add a "flags" file to give the user direct access to specify which items are valid in the ACPI SET_ERROR_TYPE_WITH_ADDRESS structure. Also add new files param3 and param4 to hold all these values. For backwards compatability with old injection scripts we maintain the old behaviour if flags remains set at zero (or is reset to 0). Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
130 lines
5.5 KiB
Plaintext
130 lines
5.5 KiB
Plaintext
APEI Error INJection
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~~~~~~~~~~~~~~~~~~~~
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EINJ provides a hardware error injection mechanism
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It is very useful for debugging and testing of other APEI and RAS features.
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To use EINJ, make sure the following are enabled in your kernel
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configuration:
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CONFIG_DEBUG_FS
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CONFIG_ACPI_APEI
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CONFIG_ACPI_APEI_EINJ
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The user interface of EINJ is debug file system, under the
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directory apei/einj. The following files are provided.
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- available_error_type
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Reading this file returns the error injection capability of the
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platform, that is, which error types are supported. The error type
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definition is as follow, the left field is the error type value, the
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right field is error description.
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0x00000001 Processor Correctable
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0x00000002 Processor Uncorrectable non-fatal
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0x00000004 Processor Uncorrectable fatal
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0x00000008 Memory Correctable
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0x00000010 Memory Uncorrectable non-fatal
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0x00000020 Memory Uncorrectable fatal
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0x00000040 PCI Express Correctable
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0x00000080 PCI Express Uncorrectable fatal
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0x00000100 PCI Express Uncorrectable non-fatal
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0x00000200 Platform Correctable
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0x00000400 Platform Uncorrectable non-fatal
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0x00000800 Platform Uncorrectable fatal
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The format of file contents are as above, except there are only the
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available error type lines.
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- error_type
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This file is used to set the error type value. The error type value
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is defined in "available_error_type" description.
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- error_inject
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Write any integer to this file to trigger the error
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injection. Before this, please specify all necessary error
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parameters.
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- flags
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Present for kernel version 3.13 and above. Used to specify which
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of param{1..4} are valid and should be used by BIOS during injection.
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Value is a bitmask as specified in ACPI5.0 spec for the
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SET_ERROR_TYPE_WITH_ADDRESS data structure:
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Bit 0 - Processor APIC field valid (see param3 below)
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Bit 1 - Memory address and mask valid (param1 and param2)
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Bit 2 - PCIe (seg,bus,dev,fn) valid (param4 below)
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If set to zero, legacy behaviour is used where the type of injection
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specifies just one bit set, and param1 is multiplexed.
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- param1
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This file is used to set the first error parameter value. Effect of
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parameter depends on error_type specified. For example, if error
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type is memory related type, the param1 should be a valid physical
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memory address. [Unless "flag" is set - see above]
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- param2
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This file is used to set the second error parameter value. Effect of
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parameter depends on error_type specified. For example, if error
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type is memory related type, the param2 should be a physical memory
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address mask. Linux requires page or narrower granularity, say,
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0xfffffffffffff000.
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- param3
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Used when the 0x1 bit is set in "flag" to specify the APIC id
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- param4
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Used when the 0x4 bit is set in "flag" to specify target PCIe device
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- notrigger
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The EINJ mechanism is a two step process. First inject the error, then
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perform some actions to trigger it. Setting "notrigger" to 1 skips the
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trigger phase, which *may* allow the user to cause the error in some other
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context by a simple access to the cpu, memory location, or device that is
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the target of the error injection. Whether this actually works depends
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on what operations the BIOS actually includes in the trigger phase.
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BIOS versions based in the ACPI 4.0 specification have limited options
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to control where the errors are injected. Your BIOS may support an
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extension (enabled with the param_extension=1 module parameter, or
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boot command line einj.param_extension=1). This allows the address
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and mask for memory injections to be specified by the param1 and
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param2 files in apei/einj.
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BIOS versions using the ACPI 5.0 specification have more control over
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the target of the injection. For processor related errors (type 0x1,
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0x2 and 0x4) the APICID of the target should be provided using the
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param1 file in apei/einj. For memory errors (type 0x8, 0x10 and 0x20)
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the address is set using param1 with a mask in param2 (0x0 is equivalent
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to all ones). For PCI express errors (type 0x40, 0x80 and 0x100) the
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segment, bus, device and function are specified using param1:
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31 24 23 16 15 11 10 8 7 0
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+-------------------------------------------------+
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| segment | bus | device | function | reserved |
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+-------------------------------------------------+
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An ACPI 5.0 BIOS may also allow vendor specific errors to be injected.
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In this case a file named vendor will contain identifying information
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from the BIOS that hopefully will allow an application wishing to use
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the vendor specific extension to tell that they are running on a BIOS
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that supports it. All vendor extensions have the 0x80000000 bit set in
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error_type. A file vendor_flags controls the interpretation of param1
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and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor
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documentation for details (and expect changes to this API if vendors
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creativity in using this feature expands beyond our expectations).
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Example:
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# cd /sys/kernel/debug/apei/einj
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# cat available_error_type # See which errors can be injected
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0x00000002 Processor Uncorrectable non-fatal
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0x00000008 Memory Correctable
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0x00000010 Memory Uncorrectable non-fatal
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# echo 0x12345000 > param1 # Set memory address for injection
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# echo 0xfffffffffffff000 > param2 # Mask - anywhere in this page
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# echo 0x8 > error_type # Choose correctable memory error
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# echo 1 > error_inject # Inject now
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For more information about EINJ, please refer to ACPI specification
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version 4.0, section 17.5 and ACPI 5.0, section 18.6.
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