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Documentation/acpi/einj: Correct and streamline text

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Streamline and simplify formulations, improve formatting and extend the
injection example in the error injection write up for users which we
carry in Documentation/.

Add a paragraph about checking for EINJ support and expand the ACPI5.0
memory errors section, as requested by Tony.

Acked-by: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1422553845-30717-1-git-send-email-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
This commit is contained in:
Borislav Petkov 2015-01-20 17:40:43 +01:00
parent 2cd4c303a7
commit 0eac092d83
1 changed files with 118 additions and 70 deletions
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188
Documentation/acpi/apei/einj.txt
View file

@ -1,129 +1,177 @@
APEI Error INJection APEI Error INJection
~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~
EINJ provides a hardware error injection mechanism EINJ provides a hardware error injection mechanism. It is very useful
It is very useful for debugging and testing of other APEI and RAS features. for debugging and testing APEI and RAS features in general.
To use EINJ, make sure the following are enabled in your kernel You need to check whether your BIOS supports EINJ first. For that, look
for early boot messages similar to this one:
ACPI: EINJ 0x000000007370A000 000150 (v01 INTEL 00000001 INTL 00000001)
which shows that the BIOS is exposing an EINJ table - it is the
mechanism through which the injection is done.
Alternatively, look in /sys/firmware/acpi/tables for an "EINJ" file,
which is a different representation of the same thing.
It doesn't necessarily mean that EINJ is not supported if those above
don't exist: before you give up, go into BIOS setup to see if the BIOS
has an option to enable error injection. Look for something called WHEA
or similar. Often, you need to enable an ACPI5 support option prior, in
order to see the APEI,EINJ,... functionality supported and exposed by
the BIOS menu.
To use EINJ, make sure the following are options enabled in your kernel
configuration: configuration:
CONFIG_DEBUG_FS CONFIG_DEBUG_FS
CONFIG_ACPI_APEI CONFIG_ACPI_APEI
CONFIG_ACPI_APEI_EINJ CONFIG_ACPI_APEI_EINJ
The user interface of EINJ is debug file system, under the The EINJ user interface is in <debugfs mount point>/apei/einj.
directory apei/einj. The following files are provided.
The following files belong to it:
- available_error_type - 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 This file shows which error types are supported:
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 Error Type Value Error Description
available error type lines. ================ =================
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 the file contents are as above, except present are only
the available error types.
- error_type - error_type
This file is used to set the error type value. The error type value
is defined in "available_error_type" description. Set the value of the error type being injected. Possible error types
are defined in the file available_error_type above.
- error_inject - error_inject
Write any integer to this file to trigger the error
injection. Before this, please specify all necessary error Write any integer to this file to trigger the error injection. Make
parameters. sure you have specified all necessary error parameters, i.e. this
write should be the last step when injecting errors.
- flags - flags
Present for kernel version 3.13 and above. Used to specify which
of param{1..4} are valid and should be used by BIOS during injection. Present for kernel versions 3.13 and above. Used to specify which
Value is a bitmask as specified in ACPI5.0 spec for the of param{1..4} are valid and should be used by the firmware during
injection. Value is a bitmask as specified in ACPI5.0 spec for the
SET_ERROR_TYPE_WITH_ADDRESS data structure: SET_ERROR_TYPE_WITH_ADDRESS data structure:
Bit 0 - Processor APIC field valid (see param3 below)
Bit 1 - Memory address and mask valid (param1 and param2) Bit 0 - Processor APIC field valid (see param3 below).
Bit 2 - PCIe (seg,bus,dev,fn) valid (param4 below) Bit 1 - Memory address and mask valid (param1 and param2).
If set to zero, legacy behaviour is used where the type of injection Bit 2 - PCIe (seg,bus,dev,fn) valid (see param4 below).
specifies just one bit set, and param1 is multiplexed.
If set to zero, legacy behavior is mimicked where the type of
injection specifies just one bit set, and param1 is multiplexed.
- param1 - param1
This file is used to set the first error parameter value. Effect of
parameter depends on error_type specified. For example, if error This file is used to set the first error parameter value. Its effect
type is memory related type, the param1 should be a valid physical depends on the error type specified in error_type. For example, if
memory address. [Unless "flag" is set - see above] error type is memory related type, the param1 should be a valid
physical memory address. [Unless "flag" is set - see above]
- param2 - param2
This file is used to set the second error parameter value. Effect of
parameter depends on error_type specified. For example, if error Same use as param1 above. For example, if error type is of memory
type is memory related type, the param2 should be a physical memory related type, then param2 should be a physical memory address mask.
address mask. Linux requires page or narrower granularity, say, Linux requires page or narrower granularity, say, 0xfffffffffffff000.
0xfffffffffffff000.
- param3 - param3
Used when the 0x1 bit is set in "flag" to specify the APIC id
Used when the 0x1 bit is set in "flags" to specify the APIC id
- param4 - param4
Used when the 0x4 bit is set in "flag" to specify target PCIe device Used when the 0x4 bit is set in "flags" to specify target PCIe device
- notrigger - 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 The error injection mechanism is a two-step process. First inject the
to control where the errors are injected. Your BIOS may support an error, then perform some actions to trigger it. Setting "notrigger"
extension (enabled with the param_extension=1 module parameter, or to 1 skips the trigger phase, which *may* allow the user to cause the
boot command line einj.param_extension=1). This allows the address error in some other context by a simple access to the CPU, memory
and mask for memory injections to be specified by the param1 and location, or device that is the target of the error injection. Whether
param2 files in apei/einj. this actually works depends on what operations the BIOS actually
includes in the trigger phase.
BIOS versions using the ACPI 5.0 specification have more control over BIOS versions based on the ACPI 4.0 specification have limited options
the target of the injection. For processor related errors (type 0x1, in controlling where the errors are injected. Your BIOS may support an
0x2 and 0x4) the APICID of the target should be provided using the extension (enabled with the param_extension=1 module parameter, or boot
param1 file in apei/einj. For memory errors (type 0x8, 0x10 and 0x20) command line einj.param_extension=1). This allows the address and mask
the address is set using param1 with a mask in param2 (0x0 is equivalent for memory injections to be specified by the param1 and param2 files in
to all ones). For PCI express errors (type 0x40, 0x80 and 0x100) the apei/einj.
segment, bus, device and function are specified using param1:
BIOS versions based on the ACPI 5.0 specification have more control over
the target of the injection. For processor-related errors (type 0x1, 0x2
and 0x4), you can set flags to 0x3 (param3 for bit 0, and param1 and
param2 for bit 1) so that you have more information added to the error
signature being injected. The actual data passed is this:
memory_address = param1;
memory_address_range = param2;
apicid = param3;
pcie_sbdf = param4;
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 31 24 23 16 15 11 10 8 7 0
+-------------------------------------------------+ +-------------------------------------------------+
| segment | bus | device | function | reserved | | segment | bus | device | function | reserved |
+-------------------------------------------------+ +-------------------------------------------------+
An ACPI 5.0 BIOS may also allow vendor specific errors to be injected. Anyway, you get the idea, if there's doubt just take a look at the code
in drivers/acpi/apei/einj.c.
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 In this case a file named vendor will contain identifying information
from the BIOS that hopefully will allow an application wishing to use 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 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 that supports it. All vendor extensions have the 0x80000000 bit set in
error_type. A file vendor_flags controls the interpretation of param1 error_type. A file vendor_flags controls the interpretation of param1
and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor
documentation for details (and expect changes to this API if vendors documentation for details (and expect changes to this API if vendors
creativity in using this feature expands beyond our expectations). creativity in using this feature expands beyond our expectations).
Example:
An error injection example:
# cd /sys/kernel/debug/apei/einj # cd /sys/kernel/debug/apei/einj
# cat available_error_type # See which errors can be injected # cat available_error_type # See which errors can be injected
0x00000002 Processor Uncorrectable non-fatal 0x00000002 Processor Uncorrectable non-fatal
0x00000008 Memory Correctable 0x00000008 Memory Correctable
0x00000010 Memory Uncorrectable non-fatal 0x00000010 Memory Uncorrectable non-fatal
# echo 0x12345000 > param1 # Set memory address for injection # echo 0x12345000 > param1 # Set memory address for injection
# echo 0xfffffffffffff000 > param2 # Mask - anywhere in this page # echo $((-1 << 12)) > param2 # Mask 0xfffffffffffff000 - anywhere in this page
# echo 0x8 > error_type # Choose correctable memory error # echo 0x8 > error_type # Choose correctable memory error
# echo 1 > error_inject # Inject now # echo 1 > error_inject # Inject now
You should see something like this in dmesg:
[22715.830801] EDAC sbridge MC3: HANDLING MCE MEMORY ERROR
[22715.834759] EDAC sbridge MC3: CPU 0: Machine Check Event: 0 Bank 7: 8c00004000010090
[22715.834759] EDAC sbridge MC3: TSC 0
[22715.834759] EDAC sbridge MC3: ADDR 12345000 EDAC sbridge MC3: MISC 144780c86
[22715.834759] EDAC sbridge MC3: PROCESSOR 0:306e7 TIME 1422553404 SOCKET 0 APIC 0
[22716.616173] EDAC MC3: 1 CE memory read error on CPU_SrcID#0_Channel#0_DIMM#0 (channel:0 slot:0 page:0x12345 offset:0x0 grain:32 syndrome:0x0 - area:DRAM err_code:0001:0090 socket:0 channel_mask:1 rank:0)
For more information about EINJ, please refer to ACPI specification For more information about EINJ, please refer to ACPI specification
version 4.0, section 17.5 and ACPI 5.0, section 18.6. version 4.0, section 17.5 and ACPI 5.0, section 18.6.