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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-16 09:37:03 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-16 09:37:03 -0800
commit9dfe495c7b4896fb88aa745660254a9704ae5930 (patch)
tree51d753459bdbd19d13609129da2b71ba0fe9928c /Documentation
parent9936f44add987355a7d79d52e48cd12255651c0d (diff)
parent4838a0def07f5611347860b1fc0129c3fe77cc02 (diff)
downloadlinux-stericsson-9dfe495c7b4896fb88aa745660254a9704ae5930.tar.gz
Merge tag 'edac/v4.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-edac
Pull edac updates from Mauro Carvalho Chehab: "This contains the conversion of the EDAC uAPI documentation to ReST and the addition of the EDAC kAPI documentation to the driver-api docs. It also splits the EDAC headers by their functions" * tag 'edac/v4.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-edac: EDAC: Document HW_EVENT_ERR_DEFERRED type edac.rst: move concepts dictionary from edac.h edac: fix kenel-doc markups at edac.h edac: fix kernel-doc tags at the drivers/edac_*.h edac: adjust docs location at MAINTAINERS and 00-INDEX driver-api: create an edac.rst file with EDAC documentation edac: move documentation from edac_mc.c to edac_core.h edac: move documentation from edac_pci*.c to edac_pci.h edac: move documentation from edac_device to edac_core.h edac: rename edac_core.h to edac_mc.h edac: move EDAC device definitions to drivers/edac/edac_device.h edac: move EDAC PCI definitions to drivers/edac/edac_pci.h docs-rst: admin-guide: add documentation for EDAC edac.txt: Improve documentation, adding RAS introduction edac.txt: update information about newer Intel CPUs edac.txt: remove info that the Nehalem EDAC is experimental edac.txt: convert EDAC documentation to ReST edac.txt: add a section explaining the dimmX and rankX directories edac: edac_core.h: remove prototype for edac_pci_reset_delay_period() edac: edac_core.h: get rid of unused kobj_complete
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/00-INDEX2
-rw-r--r--Documentation/admin-guide/index.rst1
-rw-r--r--Documentation/admin-guide/ras.rst1190
-rw-r--r--Documentation/driver-api/edac.rst178
-rw-r--r--Documentation/driver-api/index.rst1
-rw-r--r--Documentation/edac.txt812
6 files changed, 1370 insertions, 814 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX
index 5bd4b07c2f90..c8a8eb1a2b11 100644
--- a/Documentation/00-INDEX
+++ b/Documentation/00-INDEX
@@ -152,8 +152,6 @@ driver-model/
- directory with info about Linux driver model.
early-userspace/
- info about initramfs, klibc, and userspace early during boot.
-edac.txt
- - information on EDAC - Error Detection And Correction
efi-stub.txt
- How to use the EFI boot stub to bypass GRUB or elilo on EFI systems.
eisa.txt
diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst
index 2681cbd24cdd..8ddae4e4299a 100644
--- a/Documentation/admin-guide/index.rst
+++ b/Documentation/admin-guide/index.rst
@@ -59,6 +59,7 @@ configure specific aspects of kernel behavior to your liking.
binfmt-misc
mono
java
+ ras
.. only:: subproject and html
diff --git a/Documentation/admin-guide/ras.rst b/Documentation/admin-guide/ras.rst
new file mode 100644
index 000000000000..d71340e86c27
--- /dev/null
+++ b/Documentation/admin-guide/ras.rst
@@ -0,0 +1,1190 @@
+.. include:: <isonum.txt>
+
+============================================
+Reliability, Availability and Serviceability
+============================================
+
+RAS concepts
+************
+
+Reliability, Availability and Serviceability (RAS) is a concept used on
+servers meant to measure their robusteness.
+
+Reliability
+ is the probability that a system will produce correct outputs.
+
+ * Generally measured as Mean Time Between Failures (MTBF)
+ * Enhanced by features that help to avoid, detect and repair hardware faults
+
+Availability
+ is the probability that a system is operational at a given time
+
+ * Generally measured as a percentage of downtime per a period of time
+ * Often uses mechanisms to detect and correct hardware faults in
+ runtime;
+
+Serviceability (or maintainability)
+ is the simplicity and speed with which a system can be repaired or
+ maintained
+
+ * Generally measured on Mean Time Between Repair (MTBR)
+
+Improving RAS
+-------------
+
+In order to reduce systems downtime, a system should be capable of detecting
+hardware errors, and, when possible correcting them in runtime. It should
+also provide mechanisms to detect hardware degradation, in order to warn
+the system administrator to take the action of replacing a component before
+it causes data loss or system downtime.
+
+Among the monitoring measures, the most usual ones include:
+
+* CPU – detect errors at instruction execution and at L1/L2/L3 caches;
+* Memory – add error correction logic (ECC) to detect and correct errors;
+* I/O – add CRC checksums for tranfered data;
+* Storage – RAID, journal file systems, checksums,
+ Self-Monitoring, Analysis and Reporting Technology (SMART).
+
+By monitoring the number of occurrences of error detections, it is possible
+to identify if the probability of hardware errors is increasing, and, on such
+case, do a preventive maintainance to replace a degrated component while
+those errors are correctable.
+
+Types of errors
+---------------
+
+Most mechanisms used on modern systems use use technologies like Hamming
+Codes that allow error correction when the number of errors on a bit packet
+is below a threshold. If the number of errors is above, those mechanisms
+can indicate with a high degree of confidence that an error happened, but
+they can't correct.
+
+Also, sometimes an error occur on a component that it is not used. For
+example, a part of the memory that it is not currently allocated.
+
+That defines some categories of errors:
+
+* **Correctable Error (CE)** - the error detection mechanism detected and
+ corrected the error. Such errors are usually not fatal, although some
+ Kernel mechanisms allow the system administrator to consider them as fatal.
+
+* **Uncorrected Error (UE)** - the amount of errors happened above the error
+ correction threshold, and the system was unable to auto-correct.
+
+* **Fatal Error** - when an UE error happens on a critical component of the
+ system (for example, a piece of the Kernel got corrupted by an UE), the
+ only reliable way to avoid data corruption is to hang or reboot the machine.
+
+* **Non-fatal Error** - when an UE error happens on an unused component,
+ like a CPU in power down state or an unused memory bank, the system may
+ still run, eventually replacing the affected hardware by a hot spare,
+ if available.
+
+ Also, when an error happens on an userspace process, it is also possible to
+ kill such process and let userspace restart it.
+
+The mechanism for handling non-fatal errors is usually complex and may
+require the help of some userspace application, in order to apply the
+policy desired by the system administrator.
+
+Identifying a bad hardware component
+------------------------------------
+
+Just detecting a hardware flaw is usually not enough, as the system needs
+to pinpoint to the minimal replaceable unit (MRU) that should be exchanged
+to make the hardware reliable again.
+
+So, it requires not only error logging facilities, but also mechanisms that
+will translate the error message to the silkscreen or component label for
+the MRU.
+
+Typically, it is very complex for memory, as modern CPUs interlace memory
+from different memory modules, in order to provide a better performance. The
+DMI BIOS usually have a list of memory module labels, with can be obtained
+using the ``dmidecode`` tool. For example, on a desktop machine, it shows::
+
+ Memory Device
+ Total Width: 64 bits
+ Data Width: 64 bits
+ Size: 16384 MB
+ Form Factor: SODIMM
+ Set: None
+ Locator: ChannelA-DIMM0
+ Bank Locator: BANK 0
+ Type: DDR4
+ Type Detail: Synchronous
+ Speed: 2133 MHz
+ Rank: 2
+ Configured Clock Speed: 2133 MHz
+
+On the above example, a DDR4 SO-DIMM memory module is located at the
+system's memory labeled as "BANK 0", as given by the *bank locator* field.
+Please notice that, on such system, the *total width* is equal to the
+*data witdh*. It means that such memory module doesn't have error
+detection/correction mechanisms.
+
+Unfortunately, not all systems use the same field to specify the memory
+bank. On this example, from an older server, ``dmidecode`` shows::
+
+ Memory Device
+ Array Handle: 0x1000
+ Error Information Handle: Not Provided
+ Total Width: 72 bits
+ Data Width: 64 bits
+ Size: 8192 MB
+ Form Factor: DIMM
+ Set: 1
+ Locator: DIMM_A1
+ Bank Locator: Not Specified
+ Type: DDR3
+ Type Detail: Synchronous Registered (Buffered)
+ Speed: 1600 MHz
+ Rank: 2
+ Configured Clock Speed: 1600 MHz
+
+There, the DDR3 RDIMM memory module is located at the system's memory labeled
+as "DIMM_A1", as given by the *locator* field. Please notice that this
+memory module has 64 bits of *data witdh* and 72 bits of *total width*. So,
+it has 8 extra bits to be used by error detection and correction mechanisms.
+Such kind of memory is called Error-correcting code memory (ECC memory).
+
+To make things even worse, it is not uncommon that systems with different
+labels on their system's board to use exactly the same BIOS, meaning that
+the labels provided by the BIOS won't match the real ones.
+
+ECC memory
+----------
+
+As mentioned on the previous section, ECC memory has extra bits to be
+used for error correction. So, on 64 bit systems, a memory module
+has 64 bits of *data width*, and 74 bits of *total width*. So, there are
+8 bits extra bits to be used for the error detection and correction
+mechanisms. Those extra bits are called *syndrome*\ [#f1]_\ [#f2]_.
+
+So, when the cpu requests the memory controller to write a word with
+*data width*, the memory controller calculates the *syndrome* in real time,
+using Hamming code, or some other error correction code, like SECDED+,
+producing a code with *total width* size. Such code is then written
+on the memory modules.
+
+At read, the *total width* bits code is converted back, using the same
+ECC code used on write, producing a word with *data width* and a *syndrome*.
+The word with *data width* is sent to the CPU, even when errors happen.
+
+The memory controller also looks at the *syndrome* in order to check if
+there was an error, and if the ECC code was able to fix such error.
+If the error was corrected, a Corrected Error (CE) happened. If not, an
+Uncorrected Error (UE) happened.
+
+The information about the CE/UE errors is stored on some special registers
+at the memory controller and can be accessed by reading such registers,
+either by BIOS, by some special CPUs or by Linux EDAC driver. On x86 64
+bit CPUs, such errors can also be retrieved via the Machine Check
+Architecture (MCA)\ [#f3]_.
+
+.. [#f1] Please notice that several memory controllers allow operation on a
+ mode called "Lock-Step", where it groups two memory modules together,
+ doing 128-bit reads/writes. That gives 16 bits for error correction, with
+ significatively improves the error correction mechanism, at the expense
+ that, when an error happens, there's no way to know what memory module is
+ to blame. So, it has to blame both memory modules.
+
+.. [#f2] Some memory controllers also allow using memory in mirror mode.
+ On such mode, the same data is written to two memory modules. At read,
+ the system checks both memory modules, in order to check if both provide
+ identical data. On such configuration, when an error happens, there's no
+ way to know what memory module is to blame. So, it has to blame both
+ memory modules (or 4 memory modules, if the system is also on Lock-step
+ mode).
+
+.. [#f3] For more details about the Machine Check Architecture (MCA),
+ please read Documentation/x86/x86_64/machinecheck at the Kernel tree.
+
+EDAC - Error Detection And Correction
+*************************************
+
+.. note::
+
+ "bluesmoke" was the name for this device driver subsystem when it
+ was "out-of-tree" and maintained at http://bluesmoke.sourceforge.net.
+ That site is mostly archaic now and can be used only for historical
+ purposes.
+
+ When the subsystem was pushed upstream for the first time, on
+ Kernel 2.6.16, for the first time, it was renamed to ``EDAC``.
+
+Purpose
+-------
+
+The ``edac`` kernel module's goal is to detect and report hardware errors
+that occur within the computer system running under linux.
+
+Memory
+------
+
+Memory Correctable Errors (CE) and Uncorrectable Errors (UE) are the
+primary errors being harvested. These types of errors are harvested by
+the ``edac_mc`` device.
+
+Detecting CE events, then harvesting those events and reporting them,
+**can** but must not necessarily be a predictor of future UE events. With
+CE events only, the system can and will continue to operate as no data
+has been damaged yet.
+
+However, preventive maintenance and proactive part replacement of memory
+modules exhibiting CEs can reduce the likelihood of the dreaded UE events
+and system panics.
+
+Other hardware elements
+-----------------------
+
+A new feature for EDAC, the ``edac_device`` class of device, was added in
+the 2.6.23 version of the kernel.
+
+This new device type allows for non-memory type of ECC hardware detectors
+to have their states harvested and presented to userspace via the sysfs
+interface.
+
+Some architectures have ECC detectors for L1, L2 and L3 caches,
+along with DMA engines, fabric switches, main data path switches,
+interconnections, and various other hardware data paths. If the hardware
+reports it, then a edac_device device probably can be constructed to
+harvest and present that to userspace.
+
+
+PCI bus scanning
+----------------
+
+In addition, PCI devices are scanned for PCI Bus Parity and SERR Errors
+in order to determine if errors are occurring during data transfers.
+
+The presence of PCI Parity errors must be examined with a grain of salt.
+There are several add-in adapters that do **not** follow the PCI specification
+with regards to Parity generation and reporting. The specification says
+the vendor should tie the parity status bits to 0 if they do not intend
+to generate parity. Some vendors do not do this, and thus the parity bit
+can "float" giving false positives.
+
+There is a PCI device attribute located in sysfs that is checked by
+the EDAC PCI scanning code. If that attribute is set, PCI parity/error
+scanning is skipped for that device. The attribute is::
+
+ broken_parity_status
+
+and is located in ``/sys/devices/pci<XXX>/0000:XX:YY.Z`` directories for
+PCI devices.
+
+
+Versioning
+----------
+
+EDAC is composed of a "core" module (``edac_core.ko``) and several Memory
+Controller (MC) driver modules. On a given system, the CORE is loaded
+and one MC driver will be loaded. Both the CORE and the MC driver (or
+``edac_device`` driver) have individual versions that reflect current
+release level of their respective modules.
+
+Thus, to "report" on what version a system is running, one must report
+both the CORE's and the MC driver's versions.
+
+
+Loading
+-------
+
+If ``edac`` was statically linked with the kernel then no loading
+is necessary. If ``edac`` was built as modules then simply modprobe
+the ``edac`` pieces that you need. You should be able to modprobe
+hardware-specific modules and have the dependencies load the necessary
+core modules.
+
+Example::
+
+ $ modprobe amd76x_edac
+
+loads both the ``amd76x_edac.ko`` memory controller module and the
+``edac_mc.ko`` core module.
+
+
+Sysfs interface
+---------------
+
+EDAC presents a ``sysfs`` interface for control and reporting purposes. It
+lives in the /sys/devices/system/edac directory.
+
+Within this directory there currently reside 2 components:
+
+ ======= ==============================
+ mc memory controller(s) system
+ pci PCI control and status system
+ ======= ==============================
+
+
+
+Memory Controller (mc) Model
+----------------------------
+
+Each ``mc`` device controls a set of memory modules [#f4]_. These modules
+are laid out in a Chip-Select Row (``csrowX``) and Channel table (``chX``).
+There can be multiple csrows and multiple channels.
+
+.. [#f4] Nowadays, the term DIMM (Dual In-line Memory Module) is widely
+ used to refer to a memory module, although there are other memory
+ packaging alternatives, like SO-DIMM, SIMM, etc. Along this document,
+ and inside the EDAC system, the term "dimm" is used for all memory
+ modules, even when they use a different kind of packaging.
+
+Memory controllers allow for several csrows, with 8 csrows being a
+typical value. Yet, the actual number of csrows depends on the layout of
+a given motherboard, memory controller and memory module characteristics.
+
+Dual channels allow for dual data length (e. g. 128 bits, on 64 bit systems)
+data transfers to/from the CPU from/to memory. Some newer chipsets allow
+for more than 2 channels, like Fully Buffered DIMMs (FB-DIMMs) memory
+controllers. The following example will assume 2 channels:
+
+ +------------+-----------------------+
+ | Chip | Channels |
+ | Select +-----------+-----------+
+ | rows | ``ch0`` | ``ch1`` |
+ +============+===========+===========+
+ | ``csrow0`` | DIMM_A0 | DIMM_B0 |
+ +------------+ | |
+ | ``csrow1`` | | |
+ +------------+-----------+-----------+
+ | ``csrow2`` | DIMM_A1 | DIMM_B1 |
+ +------------+ | |
+ | ``csrow3`` | | |
+ +------------+-----------+-----------+
+
+In the above example, there are 4 physical slots on the motherboard
+for memory DIMMs:
+
+ +---------+---------+
+ | DIMM_A0 | DIMM_B0 |
+ +---------+---------+
+ | DIMM_A1 | DIMM_B1 |
+ +---------+---------+
+
+Labels for these slots are usually silk-screened on the motherboard.
+Slots labeled ``A`` are channel 0 in this example. Slots labeled ``B`` are
+channel 1. Notice that there are two csrows possible on a physical DIMM.
+These csrows are allocated their csrow assignment based on the slot into
+which the memory DIMM is placed. Thus, when 1 DIMM is placed in each
+Channel, the csrows cross both DIMMs.
+
+Memory DIMMs come single or dual "ranked". A rank is a populated csrow.
+Thus, 2 single ranked DIMMs, placed in slots DIMM_A0 and DIMM_B0 above
+will have just one csrow (csrow0). csrow1 will be empty. On the other
+hand, when 2 dual ranked DIMMs are similarly placed, then both csrow0
+and csrow1 will be populated. The pattern repeats itself for csrow2 and
+csrow3.
+
+The representation of the above is reflected in the directory
+tree in EDAC's sysfs interface. Starting in directory
+``/sys/devices/system/edac/mc``, each memory controller will be
+represented by its own ``mcX`` directory, where ``X`` is the
+index of the MC::
+
+ ..../edac/mc/
+ |
+ |->mc0
+ |->mc1
+ |->mc2
+ ....
+
+Under each ``mcX`` directory each ``csrowX`` is again represented by a
+``csrowX``, where ``X`` is the csrow index::
+
+ .../mc/mc0/
+ |
+ |->csrow0
+ |->csrow2
+ |->csrow3
+ ....
+
+Notice that there is no csrow1, which indicates that csrow0 is composed
+of a single ranked DIMMs. This should also apply in both Channels, in
+order to have dual-channel mode be operational. Since both csrow2 and
+csrow3 are populated, this indicates a dual ranked set of DIMMs for
+channels 0 and 1.
+
+Within each of the ``mcX`` and ``csrowX`` directories are several EDAC
+control and attribute files.
+
+``mcX`` directories
+-------------------
+
+In ``mcX`` directories are EDAC control and attribute files for
+this ``X`` instance of the memory controllers.
+
+For a description of the sysfs API, please see:
+
+ Documentation/ABI/testing/sysfs-devices-edac
+
+
+``dimmX`` or ``rankX`` directories
+----------------------------------
+
+The recommended way to use the EDAC subsystem is to look at the information
+provided by the ``dimmX`` or ``rankX`` directories [#f5]_.
+
+A typical EDAC system has the following structure under
+``/sys/devices/system/edac/``\ [#f6]_::
+
+ /sys/devices/system/edac/
+ ├── mc
+ │   ├── mc0
+ │   │   ├── ce_count
+ │   │   ├── ce_noinfo_count
+ │   │   ├── dimm0
+ │   │   │   ├── dimm_dev_type
+ │   │   │   ├── dimm_edac_mode
+ │   │   │   ├── dimm_label
+ │   │   │   ├── dimm_location
+ │   │   │   ├── dimm_mem_type
+ │   │   │   ├── size
+ │   │   │   └── uevent
+ │   │   ├── max_location
+ │   │   ├── mc_name
+ │   │   ├── reset_counters
+ │   │   ├── seconds_since_reset
+ │   │   ├── size_mb
+ │   │   ├── ue_count
+ │   │   ├── ue_noinfo_count
+ │   │   └── uevent
+ │   ├── mc1
+ │   │   ├── ce_count
+ │   │   ├── ce_noinfo_count
+ │   │   ├── dimm0
+ │   │   │   ├── dimm_dev_type
+ │   │   │   ├── dimm_edac_mode
+ │   │   │   ├── dimm_label
+ │   │   │   ├── dimm_location
+ │   │   │   ├── dimm_mem_type
+ │   │   │   ├── size
+ │   │   │   └── uevent
+ │   │   ├── max_location
+ │   │   ├── mc_name
+ │   │   ├── reset_counters
+ │   │   ├── seconds_since_reset
+ │   │   ├── size_mb
+ │   │   ├── ue_count
+ │   │   ├── ue_noinfo_count
+ │   │   └── uevent
+ │   └── uevent
+ └── uevent
+
+In the ``dimmX`` directories are EDAC control and attribute files for
+this ``X`` memory module:
+
+- ``size`` - Total memory managed by this csrow attribute file
+
+ This attribute file displays, in count of megabytes, the memory
+ that this csrow contains.
+
+- ``dimm_dev_type`` - Device type attribute file
+
+ This attribute file will display what type of DRAM device is
+ being utilized on this DIMM.
+ Examples:
+
+ - x1
+ - x2
+ - x4
+ - x8
+
+- ``dimm_edac_mode`` - EDAC Mode of operation attribute file
+
+ This attribute file will display what type of Error detection
+ and correction is being utilized.
+
+- ``dimm_label`` - memory module label control file
+
+ This control file allows this DIMM to have a label assigned
+ to it. With this label in the module, when errors occur
+ the output can provide the DIMM label in the system log.
+ This becomes vital for panic events to isolate the
+ cause of the UE event.
+
+ DIMM Labels must be assigned after booting, with information
+ that correctly identifies the physical slot with its
+ silk screen label. This information is currently very
+ motherboard specific and determination of this information
+ must occur in userland at this time.
+
+- ``dimm_location`` - location of the memory module
+
+ The location can have up to 3 levels, and describe how the
+ memory controller identifies the location of a memory module.
+ Depending on the type of memory and memory controller, it
+ can be:
+
+ - *csrow* and *channel* - used when the memory controller
+ doesn't identify a single DIMM - e. g. in ``rankX`` dir;
+ - *branch*, *channel*, *slot* - typically used on FB-DIMM memory
+ controllers;
+ - *channel*, *slot* - used on Nehalem and newer Intel drivers.
+
+- ``dimm_mem_type`` - Memory Type attribute file
+
+ This attribute file will display what type of memory is currently
+ on this csrow. Normally, either buffered or unbuffered memory.
+ Examples:
+
+ - Registered-DDR
+ - Unbuffered-DDR
+
+.. [#f5] On some systems, the memory controller doesn't have any logic
+ to identify the memory module. On such systems, the directory is called ``rankX`` and works on a similar way as the ``csrowX`` directories.
+ On modern Intel memory controllers, the memory controller identifies the
+ memory modules directly. On such systems, the directory is called ``dimmX``.
+
+.. [#f6] There are also some ``power`` directories and ``subsystem``
+ symlinks inside the sysfs mapping that are automatically created by
+ the sysfs subsystem. Currently, they serve no purpose.
+
+``csrowX`` directories
+----------------------
+
+When CONFIG_EDAC_LEGACY_SYSFS is enabled, sysfs will contain the ``csrowX``
+directories. As this API doesn't work properly for Rambus, FB-DIMMs and
+modern Intel Memory Controllers, this is being deprecated in favor of
+``dimmX`` directories.
+
+In the ``csrowX`` directories are EDAC control and attribute files for
+this ``X`` instance of csrow:
+
+
+- ``ue_count`` - Total Uncorrectable Errors count attribute file
+
+ This attribute file displays the total count of uncorrectable
+ errors that have occurred on this csrow. If panic_on_ue is set
+ this counter will not have a chance to increment, since EDAC
+ will panic the system.
+
+
+- ``ce_count`` - Total Correctable Errors count attribute file
+
+ This attribute file displays the total count of correctable
+ errors that have occurred on this csrow. This count is very
+ important to examine. CEs provide early indications that a
+ DIMM is beginning to fail. This count field should be
+ monitored for non-zero values and report such information
+ to the system administrator.
+
+
+- ``size_mb`` - Total memory managed by this csrow attribute file
+
+ This attribute file displays, in count of megabytes, the memory
+ that this csrow contains.
+
+
+- ``mem_type`` - Memory Type attribute file
+
+ This attribute file will display what type of memory is currently
+ on this csrow. Normally, either buffered or unbuffered memory.
+ Examples:
+
+ - Registered-DDR
+ - Unbuffered-DDR
+
+
+- ``edac_mode`` - EDAC Mode of operation attribute file
+
+ This attribute file will display what type of Error detection
+ and correction is being utilized.
+
+
+- ``dev_type`` - Device type attribute file
+
+ This attribute file will display what type of DRAM device is
+ being utilized on this DIMM.
+ Examples:
+
+ - x1
+ - x2
+ - x4
+ - x8
+
+
+- ``ch0_ce_count`` - Channel 0 CE Count attribute file
+
+ This attribute file will display the count of CEs on this
+ DIMM located in channel 0.
+
+
+- ``ch0_ue_count`` - Channel 0 UE Count attribute file
+
+ This attribute file will display the count of UEs on this
+ DIMM located in channel 0.
+
+
+- ``ch0_dimm_label`` - Channel 0 DIMM Label control file
+
+
+ This control file allows this DIMM to have a label assigned
+ to it. With this label in the module, when errors occur
+ the output can provide the DIMM label in the system log.
+ This becomes vital for panic events to isolate the
+ cause of the UE event.
+
+ DIMM Labels must be assigned after booting, with information
+ that correctly identifies the physical slot with its
+ silk screen label. This information is currently very
+ motherboard specific and determination of this information
+ must occur in userland at this time.
+
+
+- ``ch1_ce_count`` - Channel 1 CE Count attribute file
+
+
+ This attribute file will display the count of CEs on this
+ DIMM located in channel 1.
+
+
+- ``ch1_ue_count`` - Channel 1 UE Count attribute file
+
+
+ This attribute file will display the count of UEs on this
+ DIMM located in channel 0.
+
+
+- ``ch1_dimm_label`` - Channel 1 DIMM Label control file
+
+ This control file allows this DIMM to have a label assigned
+ to it. With this label in the module, when errors occur
+ the output can provide the DIMM label in the system log.
+ This becomes vital for panic events to isolate the
+ cause of the UE event.
+
+ DIMM Labels must be assigned after booting, with information
+ that correctly identifies the physical slot with its
+ silk screen label. This information is currently very
+ motherboard specific and determination of this information
+ must occur in userland at this time.
+
+
+System Logging
+--------------
+
+If logging for UEs and CEs is enabled, then system logs will contain
+information indicating that errors have been detected::
+
+ EDAC MC0: CE page 0x283, offset 0xce0, grain 8, syndrome 0x6ec3, row 0, channel 1 "DIMM_B1": amd76x_edac
+ EDAC MC0: CE page 0x1e5, offset 0xfb0, grain 8, syndrome 0xb741, row 0, channel 1 "DIMM_B1": amd76x_edac
+
+
+The structure of the message is:
+
+ +---------------------------------------+-------------+
+ | Content + Example |
+ +=======================================+=============+
+ | The memory controller | MC0 |
+ +---------------------------------------+-------------+
+ | Error type | CE |
+ +---------------------------------------+-------------+
+ | Memory page | 0x283 |
+ +---------------------------------------+-------------+
+ | Offset in the page | 0xce0 |
+ +---------------------------------------+-------------+
+ | The byte granularity | grain 8 |
+ | or resolution of the error | |
+ +---------------------------------------+-------------+
+ | The error syndrome | 0xb741 |
+ +---------------------------------------+-------------+
+ | Memory row | row 0 +
+ +---------------------------------------+-------------+
+ | Memory channel | channel 1 |
+ +---------------------------------------+-------------+
+ | DIMM label, if set prior | DIMM B1 |
+ +---------------------------------------+-------------+
+ | And then an optional, driver-specific | |
+ | message that may have additional | |
+ | information. | |
+ +---------------------------------------+-------------+
+
+Both UEs and CEs with no info will lack all but memory controller, error
+type, a notice of "no info" and then an optional, driver-specific error
+message.
+
+
+PCI Bus Parity Detection
+------------------------
+
+On Header Type 00 devices, the primary status is looked at for any
+parity error regardless of whether parity is enabled on the device or
+not. (The spec indicates parity is generated in some cases). On Header
+Type 01 bridges, the secondary status register is also looked at to see
+if parity occurred on the bus on the other side of the bridge.
+
+
+Sysfs configuration
+-------------------
+
+Under ``/sys/devices/system/edac/pci`` are control and attribute files as
+follows:
+
+
+- ``check_pci_parity`` - Enable/Disable PCI Parity checking control file
+
+ This control file enables or disables the PCI Bus Parity scanning
+ operation. Writing a 1 to this file enables the scanning. Writing
+ a 0 to this file disables the scanning.
+
+ Enable::
+
+ echo "1" >/sys/devices/system/edac/pci/check_pci_parity
+
+ Disable::
+
+ echo "0" >/sys/devices/system/edac/pci/check_pci_parity
+
+
+- ``pci_parity_count`` - Parity Count
+
+ This attribute file will display the number of parity errors that
+ have been detected.
+
+
+Module parameters
+-----------------
+
+- ``edac_mc_panic_on_ue`` - Panic on UE control file
+
+ An uncorrectable error will cause a machine panic. This is usually
+ desirable. It is a bad idea to continue when an uncorrectable error
+ occurs - it is indeterminate what was uncorrected and the operating
+ system context might be so mangled that continuing will lead to further
+ corruption. If the kernel has MCE configured, then EDAC will never
+ notice the UE.
+
+ LOAD TIME::
+
+ module/kernel parameter: edac_mc_panic_on_ue=[0|1]
+
+ RUN TIME::
+
+ echo "1" > /sys/module/edac_core/parameters/edac_mc_panic_on_ue
+
+
+- ``edac_mc_log_ue`` - Log UE control file
+
+
+ Generate kernel messages describing uncorrectable errors. These errors
+ are reported through the system message log system. UE statistics
+ will be accumulated even when UE logging is disabled.
+
+ LOAD TIME::
+
+ module/kernel parameter: edac_mc_log_ue=[0|1]
+
+ RUN TIME::
+
+ echo "1" > /sys/module/edac_core/parameters/edac_mc_log_ue
+
+
+- ``edac_mc_log_ce`` - Log CE control file
+
+
+ Generate kernel messages describing correctable errors. These
+ errors are reported through the system message log system.
+ CE statistics will be accumulated even when CE logging is disabled.
+
+ LOAD TIME::
+
+ module/kernel parameter: edac_mc_log_ce=[0|1]
+
+ RUN TIME::
+
+ echo "1" > /sys/module/edac_core/parameters/edac_mc_log_ce
+
+
+- ``edac_mc_poll_msec`` - Polling period control file
+
+
+ The time period, in milliseconds, for polling for error information.
+ Too small a value wastes resources. Too large a value might delay
+ necessary handling of errors and might loose valuable information for
+ locating the error. 1000 milliseconds (once each second) is the current
+ default. Systems which require all the bandwidth they can get, may
+ increase this.
+
+ LOAD TIME::
+
+ module/kernel parameter: edac_mc_poll_msec=[0|1]
+
+ RUN TIME::
+
+ echo "1000" > /sys/module/edac_core/parameters/edac_mc_poll_msec
+
+
+- ``panic_on_pci_parity`` - Panic on PCI PARITY Error
+
+
+ This control file enables or disables panicking when a parity
+ error has been detected.
+
+
+ module/kernel parameter::
+
+ edac_panic_on_pci_pe=[0|1]
+
+ Enable::
+
+ echo "1" > /sys/module/edac_core/parameters/edac_panic_on_pci_pe
+
+ Disable::
+
+ echo "0" > /sys/module/edac_core/parameters/edac_panic_on_pci_pe
+
+
+
+EDAC device type
+----------------
+
+In the header file, edac_pci.h, there is a series of edac_device structures
+and APIs for the EDAC_DEVICE.
+
+User space access to an edac_device is through the sysfs interface.
+
+At the location ``/sys/devices/system/edac`` (sysfs) new edac_device devices
+will appear.
+
+There is a three level tree beneath the above ``edac`` directory. For example,
+the ``test_device_edac`` device (found at the http://bluesmoke.sourceforget.net
+website) installs itself as::
+
+ /sys/devices/system/edac/test-instance
+
+in this directory are various controls, a symlink and one or more ``instance``
+directories.
+
+The standard default controls are:
+
+ ============== =======================================================
+ log_ce boolean to log CE events
+ log_ue boolean to log UE events
+ panic_on_ue boolean to ``panic`` the system if an UE is encountered
+ (default off, can be set true via startup script)
+ poll_msec time period between POLL cycles for events
+ ============== =======================================================
+
+The test_device_edac device adds at least one of its own custom control:
+
+ ============== ==================================================
+ test_bits which in the current test driver does nothing but
+ show how it is installed. A ported driver can
+ add one or more such controls and/or attributes
+ for specific uses.
+ One out-of-tree driver uses controls here to allow
+ for ERROR INJECTION operations to hardware
+ injection registers
+ ============== ==================================================
+
+The symlink points to the 'struct dev' that is registered for this edac_device.
+
+Instances
+---------
+
+One or more instance directories are present. For the ``test_device_edac``
+case:
+
+ +----------------+
+ | test-instance0 |
+ +----------------+
+
+
+In this directory there are two default counter attributes, which are totals of
+counter in deeper subdirectories.
+
+ ============== ====================================
+ ce_count total of CE events of subdirectories
+ ue_count total of UE events of subdirectories
+ ============== ====================================
+
+Blocks
+------
+
+At the lowest directory level is the ``block`` directory. There can be 0, 1
+or more blocks specified in each instance:
+
+ +-------------+
+ | test-block0 |
+ +-------------+
+
+In this directory the default attributes are:
+
+ ============== ================================================
+ ce_count which is counter of CE events for this ``block``
+ of hardware being monitored
+ ue_count which is counter of UE events for this ``block``
+ of hardware being monitored
+ ============== ================================================
+
+
+The ``test_device_edac`` device adds 4 attributes and 1 control:
+
+ ================== ====================================================
+ test-block-bits-0 for every POLL cycle this counter
+ is incremented
+ test-block-bits-1 every 10 cycles, this counter is bumped once,
+ and test-block-bits-0 is set to 0
+ test-block-bits-2 every 100 cycles, this counter is bumped once,
+ and test-block-bits-1 is set to 0
+ test-block-bits-3 every 1000 cycles, this counter is bumped once,
+ and test-block-bits-2 is set to 0
+ ================== ====================================================
+
+
+ ================== ====================================================
+ reset-counters writing ANY thing to this control will
+ reset all the above counters.
+ ================== ====================================================
+
+
+Use of the ``test_device_edac`` driver should enable any others to create their own
+unique drivers for their hardware systems.
+
+The ``test_device_edac`` sample driver is located at the
+http://bluesmoke.sourceforge.net project site for EDAC.
+
+
+Usage of EDAC APIs on Nehalem and newer Intel CPUs
+--------------------------------------------------
+
+On older Intel architectures, the memory controller was part of the North
+Bridge chipset. Nehalem, Sandy Bridge, Ivy Bridge, Haswell, Sky Lake and
+newer Intel architectures integrated an enhanced version of the memory
+controller (MC) inside the CPUs.
+
+This chapter will cover the differences of the enhanced memory controllers
+found on newer Intel CPUs, such as ``i7core_edac``, ``sb_edac`` and
+``sbx_edac`` drivers.
+
+.. note::
+
+ The Xeon E7 processor families use a separate chip for the memory
+ controller, called Intel Scalable Memory Buffer. This section doesn't
+ apply for such families.
+
+1) There is one Memory Controller per Quick Patch Interconnect
+ (QPI). At the driver, the term "socket" means one QPI. This is
+ associated with a physical CPU socket.
+
+ Each MC have 3 physical read channels, 3 physical write channels and
+ 3 logic channels. The driver currently sees it as just 3 channels.
+ Each channel can have up to 3 DIMMs.
+
+ The minimum known unity is DIMMs. There are no information about csrows.
+ As EDAC API maps the minimum unity is csrows, the driver sequentially
+ maps channel/DIMM into different csrows.
+
+ For example, supposing the following layout::
+
+ Ch0 phy rd0, wr0 (0x063f4031): 2 ranks, UDIMMs
+ dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
+ dimm 1 1024 Mb offset: 4, bank: 8, rank: 1, row: 0x4000, col: 0x400
+ Ch1 phy rd1, wr1 (0x063f4031): 2 ranks, UDIMMs
+ dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
+ Ch2 phy rd3, wr3 (0x063f4031): 2 ranks, UDIMMs
+ dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
+
+ The driver will map it as::
+
+ csrow0: channel 0, dimm0
+ csrow1: channel 0, dimm1
+ csrow2: channel 1, dimm0
+ csrow3: channel 2, dimm0
+
+ exports one DIMM per csrow.
+
+ Each QPI is exported as a different memory controller.
+
+2) The MC has the ability to inject errors to test drivers. The drivers
+ implement this functionality via some error injection nodes:
+
+ For injecting a memory error, there are some sysfs nodes, under
+ ``/sys/devices/system/edac/mc/mc?/``:
+
+ - ``inject_addrmatch/*``:
+ Controls the error injection mask register. It is possible to specify
+ several characteristics of the address to match an error code::
+
+ dimm = the affected dimm. Numbers are relative to a channel;
+ rank = the memory rank;
+ channel = the channel that will generate an error;
+ bank = the affected bank;
+ page = the page address;
+ column (or col) = the address column.
+
+ each of the above values can be set to "any" to match any valid value.
+
+ At driver init, all values are set to any.
+
+ For example, to generate an error at rank 1 of dimm 2, for any channel,
+ any bank, any page, any column::
+
+ echo 2 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/dimm
+ echo 1 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/rank
+
+ To return to the default behaviour of matching any, you can do::
+
+ echo any >/sys/devices/system/edac/mc/mc0/inject_addrmatch/dimm
+ echo any >/sys/devices/system/edac/mc/mc0/inject_addrmatch/rank
+
+ - ``inject_eccmask``:
+ specifies what bits will have troubles,
+
+ - ``inject_section``:
+ specifies what ECC cache section will get the error::
+
+ 3 for both
+ 2 for the highest
+ 1 for the lowest
+
+ - ``inject_type``:
+ specifies the type of error, being a combination of the following bits::
+
+ bit 0 - repeat
+ bit 1 - ecc
+ bit 2 - parity
+
+ - ``inject_enable``:
+ starts the error generation when something different than 0 is written.
+
+ All inject vars can be read. root permission is needed for write.
+
+ Datasheet states that the error will only be generated after a write on an
+ address that matches inject_addrmatch. It seems, however, that reading will
+ also produce an error.
+
+ For example, the following code will generate an error for any write access
+ at socket 0, on any DIMM/address on channel 2::
+
+ echo 2 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/channel
+ echo 2 >/sys/devices/system/edac/mc/mc0/inject_type
+ echo 64 >/sys/devices/system/edac/mc/mc0/inject_eccmask
+ echo 3 >/sys/devices/system/edac/mc/mc0/inject_section
+ echo 1 >/sys/devices/system/edac/mc/mc0/inject_enable
+ dd if=/dev/mem of=/dev/null seek=16k bs=4k count=1 >& /dev/null
+
+ For socket 1, it is needed to replace "mc0" by "mc1" at the above
+ commands.
+
+ The generated error message will look like::
+
+ EDAC MC0: UE row 0, channel-a= 0 channel-b= 0 labels "-": NON_FATAL (addr = 0x0075b980, socket=0, Dimm=0, Channel=2, syndrome=0x00000040, count=1, Err=8c0000400001009f:4000080482 (read error: read ECC error))
+
+3) Corrected Error memory register counters
+
+ Those newer MCs have some registers to count memory errors. The driver
+ uses those registers to report Corrected Errors on devices with Registered
+ DIMMs.
+
+ However, those counters don't work with Unregistered DIMM. As the chipset
+ offers some counters that also work with UDIMMs (but with a worse level of
+ granularity than the default ones), the driver exposes those registers for
+ UDIMM memories.
+
+ They can be read by looking at the contents of ``all_channel_counts/``::
+
+ $ for i in /sys/devices/system/edac/mc/mc0/all_channel_counts/*; do echo $i; cat $i; done
+ /sys/devices/system/edac/mc/mc0/all_channel_counts/udimm0
+ 0
+ /sys/devices/system/edac/mc/mc0/all_channel_counts/udimm1
+ 0
+ /sys/devices/system/edac/mc/mc0/all_channel_counts/udimm2
+ 0
+
+ What happens here is that errors on different csrows, but at the same
+ dimm number will increment the same counter.
+ So, in this memory mapping::
+
+ csrow0: channel 0, dimm0
+ csrow1: channel 0, dimm1
+ csrow2: channel 1, dimm0
+ csrow3: channel 2, dimm0
+
+ The hardware will increment udimm0 for an error at the first dimm at either
+ csrow0, csrow2 or csrow3;
+
+ The hardware will increment udimm1 for an error at the second dimm at either
+ csrow0, csrow2 or csrow3;
+
+ The hardware will increment udimm2 for an error at the third dimm at either
+ csrow0, csrow2 or csrow3;
+
+4) Standard error counters
+
+ The standard error counters are generated when an mcelog error is received
+ by the driver. Since, with UDIMM, this is counted by software, it is
+ possible that some errors could be lost. With RDIMM's, they display the
+ contents of the registers
+
+Reference documents used on ``amd64_edac``
+------------------------------------------
+
+``amd64_edac`` module is based on the following documents
+(available from http://support.amd.com/en-us/search/tech-docs):
+
+1. :Title: BIOS and Kernel Developer's Guide for AMD Athlon 64 and AMD
+ Opteron Processors
+ :AMD publication #: 26094
+ :Revision: 3.26
+ :Link: http://support.amd.com/TechDocs/26094.PDF
+
+2. :Title: BIOS and Kernel Developer's Guide for AMD NPT Family 0Fh
+ Processors
+ :AMD publication #: 32559
+ :Revision: 3.00
+ :Issue Date: May 2006
+ :Link: http://support.amd.com/TechDocs/32559.pdf
+
+3. :Title: BIOS and Kernel Developer's Guide (BKDG) For AMD Family 10h
+ Processors
+ :AMD publication #: 31116
+ :Revision: 3.00
+ :Issue Date: September 07, 2007
+ :Link: http://support.amd.com/TechDocs/31116.pdf
+
+4. :Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 15h
+ Models 30h-3Fh Processors
+ :AMD publication #: 49125
+ :Revision: 3.06
+ :Issue Date: 2/12/2015 (latest release)
+ :Link: http://support.amd.com/TechDocs/49125_15h_Models_30h-3Fh_BKDG.pdf
+
+5. :Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 15h
+ Models 60h-6Fh Processors
+ :AMD publication #: 50742
+ :Revision: 3.01
+ :Issue Date: 7/23/2015 (latest release)
+ :Link: http://support.amd.com/TechDocs/50742_15h_Models_60h-6Fh_BKDG.pdf
+
+6. :Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 16h
+ Models 00h-0Fh Processors
+ :AMD publication #: 48751
+ :Revision: 3.03
+ :Issue Date: 2/23/2015 (latest release)
+ :Link: http://support.amd.com/TechDocs/48751_16h_bkdg.pdf
+
+Credits
+=======
+
+* Written by Doug Thompson <dougthompson@xmission.com>
+
+ - 7 Dec 2005
+ - 17 Jul 2007 Updated
+
+* |copy| Mauro Carvalho Chehab
+
+ - 05 Aug 2009 Nehalem interface
+ - 26 Oct 2016 Converted to ReST and cleanups at the Nehalem section
+
+* EDAC authors/maintainers:
+
+ - Doug Thompson, Dave Jiang, Dave Peterson et al,
+ - Mauro Carvalho Chehab
+ - Borislav Petkov
+ - original author: Thayne Harbaugh
diff --git a/Documentation/driver-api/edac.rst b/Documentation/driver-api/edac.rst
new file mode 100644
index 000000000000..b8c742aa0a71
--- /dev/null
+++ b/Documentation/driver-api/edac.rst
@@ -0,0 +1,178 @@
+Error Detection And Correction (EDAC) Devices
+=============================================
+
+Main Concepts used at the EDAC subsystem
+----------------------------------------
+
+There are several things to be aware of that aren't at all obvious, like
+*sockets, *socket sets*, *banks*, *rows*, *chip-select rows*, *channels*,
+etc...
+
+These are some of the many terms that are thrown about that don't always
+mean what people think they mean (Inconceivable!). In the interest of
+creating a common ground for discussion, terms and their definitions
+will be established.
+
+* Memory devices
+
+The individual DRAM chips on a memory stick. These devices commonly
+output 4 and 8 bits each (x4, x8). Grouping several of these in parallel
+provides the number of bits that the memory controller expects:
+typically 72 bits, in order to provide 64 bits + 8 bits of ECC data.
+
+* Memory Stick
+
+A printed circuit board that aggregates multiple memory devices in
+parallel. In general, this is the Field Replaceable Unit (FRU) which
+gets replaced, in the case of excessive errors. Most often it is also
+called DIMM (Dual Inline Memory Module).
+
+* Memory Socket
+
+A physical connector on the motherboard that accepts a single memory
+stick. Also called as "slot" on several datasheets.
+
+* Channel
+
+A memory controller channel, responsible to communicate with a group of
+DIMMs. Each channel has its own independent control (command) and data
+bus, and can be used independently or grouped with other channels.
+
+* Branch
+
+It is typically the highest hierarchy on a Fully-Buffered DIMM memory
+controller. Typically, it contains two channels. Two channels at the
+same branch can be used in single mode or in lockstep mode. When
+lockstep is enabled, the cacheline is doubled, but it generally brings
+some performance penalty. Also, it is generally not possible to point to
+just one memory stick when an error occurs, as the error correction code
+is calculated using two DIMMs instead of one. Due to that, it is capable
+of correcting more errors than on single mode.
+
+* Single-channel
+
+The data accessed by the memory controller is contained into one dimm
+only. E. g. if the data is 64 bits-wide, the data flows to the CPU using
+one 64 bits parallel access. Typically used with SDR, DDR, DDR2 and DDR3
+memories. FB-DIMM and RAMBUS use a different concept for channel, so
+this concept doesn't apply there.
+
+* Double-channel
+
+The data size accessed by the memory controller is interlaced into two
+dimms, accessed at the same time. E. g. if the DIMM is 64 bits-wide (72
+bits with ECC), the data flows to the CPU using a 128 bits parallel
+access.
+
+* Chip-select row
+
+This is the name of the DRAM signal used to select the DRAM ranks to be
+accessed. Common chip-select rows for single channel are 64 bits, for
+dual channel 128 bits. It may not be visible by the memory controller,
+as some DIMM types have a memory buffer that can hide direct access to
+it from the Memory Controller.
+
+* Single-Ranked stick
+
+A Single-ranked stick has 1 chip-select row of memory. Motherboards
+commonly drive two chip-select pins to a memory stick. A single-ranked
+stick, will occupy only one of those rows. The other will be unused.
+
+.. _doubleranked:
+
+* Double-Ranked stick
+
+A double-ranked stick has two chip-select rows which access different
+sets of memory devices. The two rows cannot be accessed concurrently.
+
+* Double-sided stick
+
+**DEPRECATED TERM**, see :ref:`Double-Ranked stick <doubleranked>`.
+
+A double-sided stick has two chip-select rows which access different sets
+of memory devices. The two rows cannot be accessed concurrently.
+"Double-sided" is irrespective of the memory devices being mounted on
+both sides of the memory stick.
+
+* Socket set
+
+All of the memory sticks that are required for a single memory access or
+all of the memory sticks spanned by a chip-select row. A single socket
+set has two chip-select rows and if double-sided sticks are used these
+will occupy those chip-select rows.
+
+* Bank
+
+This term is avoided because it is unclear when needing to distinguish
+between chip-select rows and socket sets.
+
+
+Memory Controllers
+------------------
+
+Most of the EDAC core is focused on doing Memory Controller error detection.
+The :c:func:`edac_mc_alloc`. It uses internally the struct ``mem_ctl_info``
+to describe the memory controllers, with is an opaque struct for the EDAC
+drivers. Only the EDAC core is allowed to touch it.
+
+.. kernel-doc:: include/linux/edac.h
+
+.. kernel-doc:: drivers/edac/edac_mc.h
+
+PCI Controllers
+---------------
+
+The EDAC subsystem provides a mechanism to handle PCI controllers by calling
+the :c:func:`edac_pci_alloc_ctl_info`. It will use the struct
+:c:type:`edac_pci_ctl_info` to describe the PCI controllers.
+
+.. kernel-doc:: drivers/edac/edac_pci.h
+
+EDAC Blocks
+-----------
+
+The EDAC subsystem also provides a generic mechanism to report errors on
+other parts of the hardware via :c:func:`edac_device_alloc_ctl_info` function.
+
+The structures :c:type:`edac_dev_sysfs_block_attribute`,
+:c:type:`edac_device_block`, :c:type:`edac_device_instance` and
+:c:type:`edac_device_ctl_info` provide a generic or abstract 'edac_device'
+representation at sysfs.
+
+This set of structures and the code that implements the APIs for the same, provide for registering EDAC type devices which are NOT standard memory or
+PCI, like:
+
+- CPU caches (L1 and L2)
+- DMA engines
+- Core CPU switches
+- Fabric switch units
+- PCIe interface controllers
+- other EDAC/ECC type devices that can be monitored for
+ errors, etc.
+
+It allows for a 2 level set of hierarchy.
+
+For example, a cache could be composed of L1, L2 and L3 levels of cache.
+Each CPU core would have its own L1 cache, while sharing L2 and maybe L3
+caches. On such case, those can be represented via the following sysfs
+nodes::
+
+ /sys/devices/system/edac/..
+
+ pci/ <existing pci directory (if available)>
+ mc/ <existing memory device directory>
+ cpu/cpu0/.. <L1 and L2 block directory>
+ /L1-cache/ce_count
+ /ue_count
+ /L2-cache/ce_count
+ /ue_count
+ cpu/cpu1/.. <L1 and L2 block directory>
+ /L1-cache/ce_count
+ /ue_count
+ /L2-cache/ce_count
+ /ue_count
+ ...
+
+ the L1 and L2 directories would be "edac_device_block's"
+
+.. kernel-doc:: drivers/edac/edac_device.h
diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
index a528178a54a5..5475a2807e7a 100644
--- a/Documentation/driver-api/index.rst
+++ b/Documentation/driver-api/index.rst
@@ -26,6 +26,7 @@ available subsections can be seen below.
spi
i2c
hsi
+ edac
miscellaneous
vme
80211/index
diff --git a/Documentation/edac.txt b/Documentation/edac.txt
deleted file mode 100644
index f89cfd85ae13..000000000000
--- a/Documentation/edac.txt
+++ /dev/null
@@ -1,812 +0,0 @@
-EDAC - Error Detection And Correction
-=====================================
-
-"bluesmoke" was the name for this device driver when it
-was "out-of-tree" and maintained at sourceforge.net -
-bluesmoke.sourceforge.net. That site is mostly archaic now and can be
-used only for historical purposes.
-
-When the subsystem was pushed into 2.6.16 for the first time, it was
-renamed to 'EDAC'.
-
-PURPOSE
--------
-
-The 'edac' kernel module's goal is to detect and report hardware errors
-that occur within the computer system running under linux.
-
-MEMORY
-------
-
-Memory Correctable Errors (CE) and Uncorrectable Errors (UE) are the
-primary errors being harvested. These types of errors are harvested by
-the 'edac_mc' device.
-
-Detecting CE events, then harvesting those events and reporting them,
-*can* but must not necessarily be a predictor of future UE events. With
-CE events only, the system can and will continue to operate as no data
-has been damaged yet.
-
-However, preventive maintenance and proactive part replacement of memory
-DIMMs exhibiting CEs can reduce the likelihood of the dreaded UE events
-and system panics.
-
-OTHER HARDWARE ELEMENTS
------------------------
-
-A new feature for EDAC, the edac_device class of device, was added in
-the 2.6.23 version of the kernel.
-
-This new device type allows for non-memory type of ECC hardware detectors
-to have their states harvested and presented to userspace via the sysfs
-interface.
-
-Some architectures have ECC detectors for L1, L2 and L3 caches,
-along with DMA engines, fabric switches, main data path switches,
-interconnections, and various other hardware data paths. If the hardware
-reports it, then a edac_device device probably can be constructed to
-harvest and present that to userspace.
-
-
-PCI BUS SCANNING
-----------------
-
-In addition, PCI devices are scanned for PCI Bus Parity and SERR Errors
-in order to determine if errors are occurring during data transfers.
-
-The presence of PCI Parity errors must be examined with a grain of salt.
-There are several add-in adapters that do *not* follow the PCI specification
-with regards to Parity generation and reporting. The specification says
-the vendor should tie the parity status bits to 0 if they do not intend
-to generate parity. Some vendors do not do this, and thus the parity bit
-can "float" giving false positives.
-
-There is a PCI device attribute located in sysfs that is checked by
-the EDAC PCI scanning code. If that attribute is set, PCI parity/error
-scanning is skipped for that device. The attribute is:
-
- broken_parity_status
-
-and is located in /sys/devices/pci<XXX>/0000:XX:YY.Z directories for
-PCI devices.
-
-
-VERSIONING
-----------
-
-EDAC is composed of a "core" module (edac_core.ko) and several Memory
-Controller (MC) driver modules. On a given system, the CORE is loaded
-and one MC driver will be loaded. Both the CORE and the MC driver (or
-edac_device driver) have individual versions that reflect current
-release level of their respective modules.
-
-Thus, to "report" on what version a system is running, one must report
-both the CORE's and the MC driver's versions.
-
-
-LOADING
--------
-
-If 'edac' was statically linked with the kernel then no loading
-is necessary. If 'edac' was built as modules then simply modprobe
-the 'edac' pieces that you need. You should be able to modprobe
-hardware-specific modules and have the dependencies load the necessary
-core modules.
-
-Example:
-
-$> modprobe amd76x_edac
-
-loads both the amd76x_edac.ko memory controller module and the edac_mc.ko
-core module.
-
-
-SYSFS INTERFACE
----------------
-
-EDAC presents a 'sysfs' interface for control and reporting purposes. It
-lives in the /sys/devices/system/edac directory.
-
-Within this directory there currently reside 2 components:
-
- mc memory controller(s) system
- pci PCI control and status system
-
-
-
-Memory Controller (mc) Model
-----------------------------
-
-Each 'mc' device controls a set of DIMM memory modules. These modules
-are laid out in a Chip-Select Row (csrowX) and Channel table (chX).
-There can be multiple csrows and multiple channels.
-
-Memory controllers allow for several csrows, with 8 csrows being a
-typical value. Yet, the actual number of csrows depends on the layout of
-a given motherboard, memory controller and DIMM characteristics.
-
-Dual channels allows for 128 bit data transfers to/from the CPU from/to
-memory. Some newer chipsets allow for more than 2 channels, like Fully
-Buffered DIMMs (FB-DIMMs). The following example will assume 2 channels:
-
-
- Channel 0 Channel 1
- ===================================
- csrow0 | DIMM_A0 | DIMM_B0 |
- csrow1 | DIMM_A0 | DIMM_B0 |
- ===================================
-
- ===================================
- csrow2 | DIMM_A1 | DIMM_B1 |
- csrow3 | DIMM_A1 | DIMM_B1 |
- ===================================
-
-In the above example table there are 4 physical slots on the motherboard
-for memory DIMMs:
-
- DIMM_A0
- DIMM_B0
- DIMM_A1
- DIMM_B1
-
-Labels for these slots are usually silk-screened on the motherboard.
-Slots labeled 'A' are channel 0 in this example. Slots labeled 'B' are
-channel 1. Notice that there are two csrows possible on a physical DIMM.
-These csrows are allocated their csrow assignment based on the slot into
-which the memory DIMM is placed. Thus, when 1 DIMM is placed in each
-Channel, the csrows cross both DIMMs.
-
-Memory DIMMs come single or dual "ranked". A rank is a populated csrow.
-Thus, 2 single ranked DIMMs, placed in slots DIMM_A0 and DIMM_B0 above
-will have 1 csrow, csrow0. csrow1 will be empty. On the other hand,
-when 2 dual ranked DIMMs are similarly placed, then both csrow0 and
-csrow1 will be populated. The pattern repeats itself for csrow2 and
-csrow3.
-
-The representation of the above is reflected in the directory
-tree in EDAC's sysfs interface. Starting in directory
-/sys/devices/system/edac/mc each memory controller will be represented
-by its own 'mcX' directory, where 'X' is the index of the MC.
-
-
- ..../edac/mc/
- |
- |->mc0
- |->mc1
- |->mc2
- ....
-
-Under each 'mcX' directory each 'csrowX' is again represented by a
-'csrowX', where 'X' is the csrow index:
-
-
- .../mc/mc0/
- |
- |->csrow0
- |->csrow2
- |->csrow3
- ....
-
-Notice that there is no csrow1, which indicates that csrow0 is composed
-of a single ranked DIMMs. This should also apply in both Channels, in
-order to have dual-channel mode be operational. Since both csrow2 and
-csrow3 are populated, this indicates a dual ranked set of DIMMs for
-channels 0 and 1.
-
-
-Within each of the 'mcX' and 'csrowX' directories are several EDAC
-control and attribute files.
-
-
-'mcX' directories
------------------
-
-In 'mcX' directories are EDAC control and attribute files for
-this 'X' instance of the memory controllers.
-
-For a description of the sysfs API, please see:
- Documentation/ABI/testing/sysfs-devices-edac
-
-
-
-'csrowX' directories
---------------------
-
-When CONFIG_EDAC_LEGACY_SYSFS is enabled, sysfs will contain the csrowX
-directories. As this API doesn't work properly for Rambus, FB-DIMMs and
-modern Intel Memory Controllers, this is being deprecated in favor of
-dimmX directories.
-
-In the 'csrowX' directories are EDAC control and attribute files for
-this 'X' instance of csrow:
-
-
-Total Uncorrectable Errors count attribute file:
-
- 'ue_count'
-
- This attribute file displays the total count of uncorrectable
- errors that have occurred on this csrow. If panic_on_ue is set
- this counter will not have a chance to increment, since EDAC
- will panic the system.
-
-
-Total Correctable Errors count attribute file:
-
- 'ce_count'
-
- This attribute file displays the total count of correctable
- errors that have occurred on this csrow. This count is very
- important to examine. CEs provide early indications that a
- DIMM is beginning to fail. This count field should be
- monitored for non-zero values and report such information
- to the system administrator.
-
-
-Total memory managed by this csrow attribute file:
-
- 'size_mb'
-
- This attribute file displays, in count of megabytes, the memory
- that this csrow contains.
-
-
-Memory Type attribute file:
-
- 'mem_type'
-
- This attribute file will display what type of memory is currently
- on this csrow. Normally, either buffered or unbuffered memory.
- Examples:
- Registered-DDR
- Unbuffered-DDR
-
-
-EDAC Mode of operation attribute file:
-
- 'edac_mode'
-
- This attribute file will display what type of Error detection
- and correction is being utilized.
-
-
-Device type attribute file:
-
- 'dev_type'
-
- This attribute file will display what type of DRAM device is
- being utilized on this DIMM.
- Examples:
- x1
- x2
- x4
- x8
-
-
-Channel 0 CE Count attribute file:
-
- 'ch0_ce_count'
-
- This attribute file will display the count of CEs on this
- DIMM located in channel 0.
-
-
-Channel 0 UE Count attribute file:
-
- 'ch0_ue_count'
-
- This attribute file will display the count of UEs on this
- DIMM located in channel 0.
-
-
-Channel 0 DIMM Label control file:
-
- 'ch0_dimm_label'
-
- This control file allows this DIMM to have a label assigned
- to it. With this label in the module, when errors occur
- the output can provide the DIMM label in the system log.
- This becomes vital for panic events to isolate the
- cause of the UE event.
-
- DIMM Labels must be assigned after booting, with information
- that correctly identifies the physical slot with its
- silk screen label. This information is currently very
- motherboard specific and determination of this information
- must occur in userland at this time.
-
-
-Channel 1 CE Count attribute file:
-
- 'ch1_ce_count'
-
- This attribute file will display the count of CEs on this
- DIMM located in channel 1.
-
-
-Channel 1 UE Count attribute file:
-
- 'ch1_ue_count'
-
- This attribute file will display the count of UEs on this
- DIMM located in channel 0.
-
-
-Channel 1 DIMM Label control file:
-
- 'ch1_dimm_label'
-
- This control file allows this DIMM to have a label assigned
- to it. With this label in the module, when errors occur
- the output can provide the DIMM label in the system log.
- This becomes vital for panic events to isolate the
- cause of the UE event.
-
- DIMM Labels must be assigned after booting, with information
- that correctly identifies the physical slot with its
- silk screen label. This information is currently very
- motherboard specific and determination of this information
- must occur in userland at this time.
-
-
-
-SYSTEM LOGGING
---------------
-
-If logging for UEs and CEs is enabled, then system logs will contain
-information indicating that errors have been detected:
-
-EDAC MC0: CE page 0x283, offset 0xce0, grain 8, syndrome 0x6ec3, row 0,
-channel 1 "DIMM_B1": amd76x_edac
-
-EDAC MC0: CE page 0x1e5, offset 0xfb0, grain 8, syndrome 0xb741, row 0,
-channel 1 "DIMM_B1": amd76x_edac
-
-
-The structure of the message is:
- the memory controller (MC0)
- Error type (CE)
- memory page (0x283)
- offset in the page (0xce0)
- the byte granularity (grain 8)
- or resolution of the error
- the error syndrome (0xb741)
- memory row (row 0)
- memory channel (channel 1)
- DIMM label, if set prior (DIMM B1
- and then an optional, driver-specific message that may
- have additional information.
-
-Both UEs and CEs with no info will lack all but memory controller, error
-type, a notice of "no info" and then an optional, driver-specific error
-message.
-
-
-PCI Bus Parity Detection
-------------------------
-
-On Header Type 00 devices, the primary status is looked at for any
-parity error regardless of whether parity is enabled on the device or
-not. (The spec indicates parity is generated in some cases). On Header
-Type 01 bridges, the secondary status register is also looked at to see
-if parity occurred on the bus on the other side of the bridge.
-
-
-SYSFS CONFIGURATION
--------------------
-
-Under /sys/devices/system/edac/pci are control and attribute files as follows:
-
-
-Enable/Disable PCI Parity checking control file:
-
- 'check_pci_parity'
-
-
- This control file enables or disables the PCI Bus Parity scanning
- operation. Writing a 1 to this file enables the scanning. Writing
- a 0 to this file disables the scanning.
-
- Enable:
- echo "1" >/sys/devices/system/edac/pci/check_pci_parity
-
- Disable:
- echo "0" >/sys/devices/system/edac/pci/check_pci_parity
-
-
-Parity Count:
-
- 'pci_parity_count'
-
- This attribute file will display the number of parity errors that
- have been detected.
-
-
-
-MODULE PARAMETERS
------------------
-
-Panic on UE control file:
-
- 'edac_mc_panic_on_ue'
-
- An uncorrectable error will cause a machine panic. This is usually
- desirable. It is a bad idea to continue when an uncorrectable error
- occurs - it is indeterminate what was uncorrected and the operating
- system context might be so mangled that continuing will lead to further
- corruption. If the kernel has MCE configured, then EDAC will never
- notice the UE.
-
- LOAD TIME: module/kernel parameter: edac_mc_panic_on_ue=[0|1]
-
- RUN TIME: echo "1" > /sys/module/edac_core/parameters/edac_mc_panic_on_ue
-
-
-Log UE control file:
-
- 'edac_mc_log_ue'
-
- Generate kernel messages describing uncorrectable errors. These errors
- are reported through the system message log system. UE statistics
- will be accumulated even when UE logging is disabled.
-
- LOAD TIME: module/kernel parameter: edac_mc_log_ue=[0|1]
-
- RUN TIME: echo "1" > /sys/module/edac_core/parameters/edac_mc_log_ue
-
-
-Log CE control file:
-
- 'edac_mc_log_ce'
-
- Generate kernel messages describing correctable errors. These
- errors are reported through the system message log system.
- CE statistics will be accumulated even when CE logging is disabled.
-
- LOAD TIME: module/kernel parameter: edac_mc_log_ce=[0|1]
-
- RUN TIME: echo "1" > /sys/module/edac_core/parameters/edac_mc_log_ce
-
-
-Polling period control file:
-
- 'edac_mc_poll_msec'
-
- The time period, in milliseconds, for polling for error information.
- Too small a value wastes resources. Too large a value might delay
- necessary handling of errors and might loose valuable information for
- locating the error. 1000 milliseconds (once each second) is the current
- default. Systems which require all the bandwidth they can get, may
- increase this.
-
- LOAD TIME: module/kernel parameter: edac_mc_poll_msec=[0|1]
-
- RUN TIME: echo "1000" > /sys/module/edac_core/parameters/edac_mc_poll_msec
-
-
-Panic on PCI PARITY Error:
-
- 'panic_on_pci_parity'
-
-
- This control file enables or disables panicking when a parity
- error has been detected.
-
-
- module/kernel parameter: edac_panic_on_pci_pe=[0|1]
-
- Enable:
- echo "1" > /sys/module/edac_core/parameters/edac_panic_on_pci_pe
-
- Disable:
- echo "0" > /sys/module/edac_core/parameters/edac_panic_on_pci_pe
-
-
-
-EDAC device type
-----------------
-
-In the header file, edac_core.h, there is a series of edac_device structures
-and APIs for the EDAC_DEVICE.
-
-User space access to an edac_device is through the sysfs interface.
-
-At the location /sys/devices/system/edac (sysfs) new edac_device devices will
-appear.
-
-There is a three level tree beneath the above 'edac' directory. For example,
-the 'test_device_edac' device (found at the bluesmoke.sourceforget.net website)
-installs itself as:
-
- /sys/devices/systm/edac/test-instance
-
-in this directory are various controls, a symlink and one or more 'instance'
-directories.
-
-The standard default controls are:
-
- log_ce boolean to log CE events
- log_ue boolean to log UE events
- panic_on_ue boolean to 'panic' the system if an UE is encountered
- (default off, can be set true via startup script)
- poll_msec time period between POLL cycles for events
-
-The test_device_edac device adds at least one of its own custom control:
-
- test_bits which in the current test driver does nothing but
- show how it is installed. A ported driver can
- add one or more such controls and/or attributes
- for specific uses.
- One out-of-tree driver uses controls here to allow
- for ERROR INJECTION operations to hardware
- injection registers
-
-The symlink points to the 'struct dev' that is registered for this edac_device.
-
-INSTANCES
----------
-
-One or more instance directories are present. For the 'test_device_edac' case:
-
- test-instance0
-
-
-In this directory there are two default counter attributes, which are totals of
-counter in deeper subdirectories.
-
- ce_count total of CE events of subdirectories
- ue_count total of UE events of subdirectories
-
-BLOCKS
-------
-
-At the lowest directory level is the 'block' directory. There can be 0, 1
-or more blocks specified in each instance.
-
- test-block0
-
-
-In this directory the default attributes are:
-
- ce_count which is counter of CE events for this 'block'
- of hardware being monitored
- ue_count which is counter of UE events for this 'block'
- of hardware being monitored
-
-
-The 'test_device_edac' device adds 4 attributes and 1 control:
-
- test-block-bits-0 for every POLL cycle this counter
- is incremented
- test-block-bits-1 every 10 cycles, this counter is bumped once,
- and test-block-bits-0 is set to 0
- test-block-bits-2 every 100 cycles, this counter is bumped once,
- and test-block-bits-1 is set to 0
- test-block-bits-3 every 1000 cycles, this counter is bumped once,
- and test-block-bits-2 is set to 0
-
-
- reset-counters writing ANY thing to this control will
- reset all the above counters.
-
-
-Use of the 'test_device_edac' driver should enable any others to create their own
-unique drivers for their hardware systems.
-
-The 'test_device_edac' sample driver is located at the
-bluesmoke.sourceforge.net project site for EDAC.
-
-
-NEHALEM USAGE OF EDAC APIs
---------------------------
-
-This chapter documents some EXPERIMENTAL mappings for EDAC API to handle
-Nehalem EDAC driver. They will likely be changed on future versions
-of the driver.
-
-Due to the way Nehalem exports Memory Controller data, some adjustments
-were done at i7core_edac driver. This chapter will cover those differences
-
-1) On Nehalem, there is one Memory Controller per Quick Patch Interconnect
- (QPI). At the driver, the term "socket" means one QPI. This is
- associated with a physical CPU socket.
-
- Each MC have 3 physical read channels, 3 physical write channels and
- 3 logic channels. The driver currently sees it as just 3 channels.
- Each channel can have up to 3 DIMMs.
-
- The minimum known unity is DIMMs. There are no information about csrows.
- As EDAC API maps the minimum unity is csrows, the driver sequentially
- maps channel/dimm into different csrows.
-
- For example, supposing the following layout:
- Ch0 phy rd0, wr0 (0x063f4031): 2 ranks, UDIMMs
- dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
- dimm 1 1024 Mb offset: 4, bank: 8, rank: 1, row: 0x4000, col: 0x400
- Ch1 phy rd1, wr1 (0x063f4031): 2 ranks, UDIMMs
- dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
- Ch2 phy rd3, wr3 (0x063f4031): 2 ranks, UDIMMs
- dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
- The driver will map it as:
- csrow0: channel 0, dimm0
- csrow1: channel 0, dimm1
- csrow2: channel 1, dimm0
- csrow3: channel 2, dimm0
-
-exports one
- DIMM per csrow.
-
- Each QPI is exported as a different memory controller.
-
-2) Nehalem MC has the ability to generate errors. The driver implements this
- functionality via some error injection nodes:
-
- For injecting a memory error, there are some sysfs nodes, under
- /sys/devices/system/edac/mc/mc?/:
-
- inject_addrmatch/*:
- Controls the error injection mask register. It is possible to specify
- several characteristics of the address to match an error code:
- dimm = the affected dimm. Numbers are relative to a channel;
- rank = the memory rank;
- channel = the channel that will generate an error;
- bank = the affected bank;
- page = the page address;
- column (or col) = the address column.
- each of the above values can be set to "any" to match any valid value.
-
- At driver init, all values are set to any.
-
- For example, to generate an error at rank 1 of dimm 2, for any channel,
- any bank, any page, any column:
- echo 2 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/dimm
- echo 1 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/rank
-
- To return to the default behaviour of matching any, you can do:
- echo any >/sys/devices/system/edac/mc/mc0/inject_addrmatch/dimm
- echo any >/sys/devices/system/edac/mc/mc0/inject_addrmatch/rank
-
- inject_eccmask:
- specifies what bits will have troubles,
-
- inject_section:
- specifies what ECC cache section will get the error:
- 3 for both
- 2 for the highest
- 1 for the lowest
-
- inject_type:
- specifies the type of error, being a combination of the following bits:
- bit 0 - repeat
- bit 1 - ecc
- bit 2 - parity
-
- inject_enable starts the error generation when something different
- than 0 is written.
-
- All inject vars can be read. root permission is needed for write.
-
- Datasheet states that the error will only be generated after a write on an
- address that matches inject_addrmatch. It seems, however, that reading will
- also produce an error.
-
- For example, the following code will generate an error for any write access
- at socket 0, on any DIMM/address on channel 2:
-
- echo 2 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/channel
- echo 2 >/sys/devices/system/edac/mc/mc0/inject_type
- echo 64 >/sys/devices/system/edac/mc/mc0/inject_eccmask
- echo 3 >/sys/devices/system/edac/mc/mc0/inject_section
- echo 1 >/sys/devices/system/edac/mc/mc0/inject_enable
- dd if=/dev/mem of=/dev/null seek=16k bs=4k count=1 >& /dev/null
-
- For socket 1, it is needed to replace "mc0" by "mc1" at the above
- commands.
-
- The generated error message will look like:
-
- EDAC MC0: UE row 0, channel-a= 0 channel-b= 0 labels "-": NON_FATAL (addr = 0x0075b980, socket=0, Dimm=0, Channel=2, syndrome=0x00000040, count=1, Err=8c0000400001009f:4000080482 (read error: read ECC error))
-
-3) Nehalem specific Corrected Error memory counters
-
- Nehalem have some registers to count memory errors. The driver uses those
- registers to report Corrected Errors on devices with Registered Dimms.
-
- However, those counters don't work with Unregistered Dimms. As the chipset
- offers some counters that also work with UDIMMS (but with a worse level of
- granularity than the default ones), the driver exposes those registers for
- UDIMM memories.
-
- They can be read by looking at the contents of all_channel_counts/
-
- $ for i in /sys/devices/system/edac/mc/mc0/all_channel_counts/*; do echo $i; cat $i; done
- /sys/devices/system/edac/mc/mc0/all_channel_counts/udimm0
- 0
- /sys/devices/system/edac/mc/mc0/all_channel_counts/udimm1
- 0
- /sys/devices/system/edac/mc/mc0/all_channel_counts/udimm2
- 0
-
- What happens here is that errors on different csrows, but at the same
- dimm number will increment the same counter.
- So, in this memory mapping:
- csrow0: channel 0, dimm0
- csrow1: channel 0, dimm1
- csrow2: channel 1, dimm0
- csrow3: channel 2, dimm0
- The hardware will increment udimm0 for an error at the first dimm at either
- csrow0, csrow2 or csrow3;
- The hardware will increment udimm1 for an error at the second dimm at either
- csrow0, csrow2 or csrow3;
- The hardware will increment udimm2 for an error at the third dimm at either
- csrow0, csrow2 or csrow3;
-
-4) Standard error counters
-
- The standard error counters are generated when an mcelog error is received
- by the driver. Since, with udimm, this is counted by software, it is
- possible that some errors could be lost. With rdimm's, they display the
- contents of the registers
-
-AMD64_EDAC REFERENCE DOCUMENTS USED
------------------------------------
-amd64_edac module is based on the following documents
-(available from http://support.amd.com/en-us/search/tech-docs):
-
-1. Title: BIOS and Kernel Developer's Guide for AMD Athlon 64 and AMD
- Opteron Processors
- AMD publication #: 26094
- Revision: 3.26
- Link: http://support.amd.com/TechDocs/26094.PDF
-
-2. Title: BIOS and Kernel Developer's Guide for AMD NPT Family 0Fh
- Processors
- AMD publication #: 32559
- Revision: 3.00
- Issue Date: May 2006
- Link: http://support.amd.com/TechDocs/32559.pdf
-
-3. Title: BIOS and Kernel Developer's Guide (BKDG) For AMD Family 10h
- Processors
- AMD publication #: 31116
- Revision: 3.00
- Issue Date: September 07, 2007
- Link: http://support.amd.com/TechDocs/31116.pdf
-
-4. Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 15h
- Models 30h-3Fh Processors
- AMD publication #: 49125
- Revision: 3.06
- Issue Date: 2/12/2015 (latest release)
- Link: http://support.amd.com/TechDocs/49125_15h_Models_30h-3Fh_BKDG.pdf
-
-5. Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 15h
- Models 60h-6Fh Processors
- AMD publication #: 50742
- Revision: 3.01
- Issue Date: 7/23/2015 (latest release)
- Link: http://support.amd.com/TechDocs/50742_15h_Models_60h-6Fh_BKDG.pdf
-
-6. Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 16h
- Models 00h-0Fh Processors
- AMD publication #: 48751
- Revision: 3.03
- Issue Date: 2/23/2015 (latest release)
- Link: http://support.amd.com/TechDocs/48751_16h_bkdg.pdf
-
-CREDITS:
-========
-
-Written by Doug Thompson <dougthompson@xmission.com>
-7 Dec 2005
-17 Jul 2007 Updated
-
-(c) Mauro Carvalho Chehab
-05 Aug 2009 Nehalem interface
-
-EDAC authors/maintainers:
-
- Doug Thompson, Dave Jiang, Dave Peterson et al,
- Mauro Carvalho Chehab
- Borislav Petkov
- original author: Thayne Harbaugh