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1EDAC - Error Detection And Correction
2=====================================
3
4"bluesmoke" was the name for this device driver when it
5was "out-of-tree" and maintained at sourceforge.net -
6bluesmoke.sourceforge.net. That site is mostly archaic now and can be
7used only for historical purposes.
8
9When the subsystem was pushed into 2.6.16 for the first time, it was
10renamed to 'EDAC'.
11
12PURPOSE
13-------
14
15The 'edac' kernel module's goal is to detect and report hardware errors
16that occur within the computer system running under linux.
17
18MEMORY
19------
20
21Memory Correctable Errors (CE) and Uncorrectable Errors (UE) are the
22primary errors being harvested. These types of errors are harvested by
23the 'edac_mc' device.
24
25Detecting CE events, then harvesting those events and reporting them,
26*can* but must not necessarily be a predictor of future UE events. With
27CE events only, the system can and will continue to operate as no data
28has been damaged yet.
29
30However, preventive maintenance and proactive part replacement of memory
31DIMMs exhibiting CEs can reduce the likelihood of the dreaded UE events
32and system panics.
33
34OTHER HARDWARE ELEMENTS
35-----------------------
36
37A new feature for EDAC, the edac_device class of device, was added in
38the 2.6.23 version of the kernel.
39
40This new device type allows for non-memory type of ECC hardware detectors
41to have their states harvested and presented to userspace via the sysfs
42interface.
43
44Some architectures have ECC detectors for L1, L2 and L3 caches,
45along with DMA engines, fabric switches, main data path switches,
46interconnections, and various other hardware data paths. If the hardware
47reports it, then a edac_device device probably can be constructed to
48harvest and present that to userspace.
49
50
51PCI BUS SCANNING
52----------------
53
54In addition, PCI devices are scanned for PCI Bus Parity and SERR Errors
55in order to determine if errors are occurring during data transfers.
56
57The presence of PCI Parity errors must be examined with a grain of salt.
58There are several add-in adapters that do *not* follow the PCI specification
59with regards to Parity generation and reporting. The specification says
60the vendor should tie the parity status bits to 0 if they do not intend
61to generate parity.  Some vendors do not do this, and thus the parity bit
62can "float" giving false positives.
63
64There is a PCI device attribute located in sysfs that is checked by
65the EDAC PCI scanning code. If that attribute is set, PCI parity/error
66scanning is skipped for that device. The attribute is:
67
68	broken_parity_status
69
70and is located in /sys/devices/pci<XXX>/0000:XX:YY.Z directories for
71PCI devices.
72
73
74VERSIONING
75----------
76
77EDAC is composed of a "core" module (edac_core.ko) and several Memory
78Controller (MC) driver modules. On a given system, the CORE is loaded
79and one MC driver will be loaded. Both the CORE and the MC driver (or
80edac_device driver) have individual versions that reflect current
81release level of their respective modules.
82
83Thus, to "report" on what version a system is running, one must report
84both the CORE's and the MC driver's versions.
85
86
87LOADING
88-------
89
90If 'edac' was statically linked with the kernel then no loading
91is necessary. If 'edac' was built as modules then simply modprobe
92the 'edac' pieces that you need. You should be able to modprobe
93hardware-specific modules and have the dependencies load the necessary
94core modules.
95
96Example:
97
98$> modprobe amd76x_edac
99
100loads both the amd76x_edac.ko memory controller module and the edac_mc.ko
101core module.
102
103
104SYSFS INTERFACE
105---------------
106
107EDAC presents a 'sysfs' interface for control and reporting purposes. It
108lives in the /sys/devices/system/edac directory.
109
110Within this directory there currently reside 2 components:
111
112	mc	memory controller(s) system
113	pci	PCI control and status system
114
115
116
117Memory Controller (mc) Model
118----------------------------
119
120Each 'mc' device controls a set of DIMM memory modules. These modules
121are laid out in a Chip-Select Row (csrowX) and Channel table (chX).
122There can be multiple csrows and multiple channels.
123
124Memory controllers allow for several csrows, with 8 csrows being a
125typical value. Yet, the actual number of csrows depends on the layout of
126a given motherboard, memory controller and DIMM characteristics.
127
128Dual channels allows for 128 bit data transfers to/from the CPU from/to
129memory. Some newer chipsets allow for more than 2 channels, like Fully
130Buffered DIMMs (FB-DIMMs). The following example will assume 2 channels:
131
132
133		Channel 0	Channel 1
134	===================================
135	csrow0	| DIMM_A0	| DIMM_B0 |
136	csrow1	| DIMM_A0	| DIMM_B0 |
137	===================================
138
139	===================================
140	csrow2	| DIMM_A1	| DIMM_B1 |
141	csrow3	| DIMM_A1	| DIMM_B1 |
142	===================================
143
144In the above example table there are 4 physical slots on the motherboard
145for memory DIMMs:
146
147	DIMM_A0
148	DIMM_B0
149	DIMM_A1
150	DIMM_B1
151
152Labels for these slots are usually silk-screened on the motherboard.
153Slots labeled 'A' are channel 0 in this example. Slots labeled 'B' are
154channel 1. Notice that there are two csrows possible on a physical DIMM.
155These csrows are allocated their csrow assignment based on the slot into
156which the memory DIMM is placed. Thus, when 1 DIMM is placed in each
157Channel, the csrows cross both DIMMs.
158
159Memory DIMMs come single or dual "ranked". A rank is a populated csrow.
160Thus, 2 single ranked DIMMs, placed in slots DIMM_A0 and DIMM_B0 above
161will have 1 csrow, csrow0. csrow1 will be empty. On the other hand,
162when 2 dual ranked DIMMs are similarly placed, then both csrow0 and
163csrow1 will be populated. The pattern repeats itself for csrow2 and
164csrow3.
165
166The representation of the above is reflected in the directory
167tree in EDAC's sysfs interface. Starting in directory
168/sys/devices/system/edac/mc each memory controller will be represented
169by its own 'mcX' directory, where 'X' is the index of the MC.
170
171
172	..../edac/mc/
173		   |
174		   |->mc0
175		   |->mc1
176		   |->mc2
177		   ....
178
179Under each 'mcX' directory each 'csrowX' is again represented by a
180'csrowX', where 'X' is the csrow index:
181
182
183	.../mc/mc0/
184		|
185		|->csrow0
186		|->csrow2
187		|->csrow3
188		....
189
190Notice that there is no csrow1, which indicates that csrow0 is composed
191of a single ranked DIMMs. This should also apply in both Channels, in
192order to have dual-channel mode be operational. Since both csrow2 and
193csrow3 are populated, this indicates a dual ranked set of DIMMs for
194channels 0 and 1.
195
196
197Within each of the 'mcX' and 'csrowX' directories are several EDAC
198control and attribute files.
199
200
201'mcX' directories
202-----------------
203
204In 'mcX' directories are EDAC control and attribute files for
205this 'X' instance of the memory controllers.
206
207For a description of the sysfs API, please see:
208	Documentation/ABI/testing/sysfs-devices-edac
209
210
211
212'csrowX' directories
213--------------------
214
215When CONFIG_EDAC_LEGACY_SYSFS is enabled, sysfs will contain the csrowX
216directories. As this API doesn't work properly for Rambus, FB-DIMMs and
217modern Intel Memory Controllers, this is being deprecated in favor of
218dimmX directories.
219
220In the 'csrowX' directories are EDAC control and attribute files for
221this 'X' instance of csrow:
222
223
224Total Uncorrectable Errors count attribute file:
225
226	'ue_count'
227
228	This attribute file displays the total count of uncorrectable
229	errors that have occurred on this csrow. If panic_on_ue is set
230	this counter will not have a chance to increment, since EDAC
231	will panic the system.
232
233
234Total Correctable Errors count attribute file:
235
236	'ce_count'
237
238	This attribute file displays the total count of correctable
239	errors that have occurred on this csrow. This count is very
240	important to examine. CEs provide early indications that a
241	DIMM is beginning to fail. This count field should be
242	monitored for non-zero values and report such information
243	to the system administrator.
244
245
246Total memory managed by this csrow attribute file:
247
248	'size_mb'
249
250	This attribute file displays, in count of megabytes, the memory
251	that this csrow contains.
252
253
254Memory Type attribute file:
255
256	'mem_type'
257
258	This attribute file will display what type of memory is currently
259	on this csrow. Normally, either buffered or unbuffered memory.
260	Examples:
261		Registered-DDR
262		Unbuffered-DDR
263
264
265EDAC Mode of operation attribute file:
266
267	'edac_mode'
268
269	This attribute file will display what type of Error detection
270	and correction is being utilized.
271
272
273Device type attribute file:
274
275	'dev_type'
276
277	This attribute file will display what type of DRAM device is
278	being utilized on this DIMM.
279	Examples:
280		x1
281		x2
282		x4
283		x8
284
285
286Channel 0 CE Count attribute file:
287
288	'ch0_ce_count'
289
290	This attribute file will display the count of CEs on this
291	DIMM located in channel 0.
292
293
294Channel 0 UE Count attribute file:
295
296	'ch0_ue_count'
297
298	This attribute file will display the count of UEs on this
299	DIMM located in channel 0.
300
301
302Channel 0 DIMM Label control file:
303
304	'ch0_dimm_label'
305
306	This control file allows this DIMM to have a label assigned
307	to it. With this label in the module, when errors occur
308	the output can provide the DIMM label in the system log.
309	This becomes vital for panic events to isolate the
310	cause of the UE event.
311
312	DIMM Labels must be assigned after booting, with information
313	that correctly identifies the physical slot with its
314	silk screen label. This information is currently very
315	motherboard specific and determination of this information
316	must occur in userland at this time.
317
318
319Channel 1 CE Count attribute file:
320
321	'ch1_ce_count'
322
323	This attribute file will display the count of CEs on this
324	DIMM located in channel 1.
325
326
327Channel 1 UE Count attribute file:
328
329	'ch1_ue_count'
330
331	This attribute file will display the count of UEs on this
332	DIMM located in channel 0.
333
334
335Channel 1 DIMM Label control file:
336
337	'ch1_dimm_label'
338
339	This control file allows this DIMM to have a label assigned
340	to it. With this label in the module, when errors occur
341	the output can provide the DIMM label in the system log.
342	This becomes vital for panic events to isolate the
343	cause of the UE event.
344
345	DIMM Labels must be assigned after booting, with information
346	that correctly identifies the physical slot with its
347	silk screen label. This information is currently very
348	motherboard specific and determination of this information
349	must occur in userland at this time.
350
351
352
353SYSTEM LOGGING
354--------------
355
356If logging for UEs and CEs is enabled, then system logs will contain
357information indicating that errors have been detected:
358
359EDAC MC0: CE page 0x283, offset 0xce0, grain 8, syndrome 0x6ec3, row 0,
360channel 1 "DIMM_B1": amd76x_edac
361
362EDAC MC0: CE page 0x1e5, offset 0xfb0, grain 8, syndrome 0xb741, row 0,
363channel 1 "DIMM_B1": amd76x_edac
364
365
366The structure of the message is:
367	the memory controller			(MC0)
368	Error type				(CE)
369	memory page				(0x283)
370	offset in the page			(0xce0)
371	the byte granularity 			(grain 8)
372		or resolution of the error
373	the error syndrome			(0xb741)
374	memory row				(row 0)
375	memory channel				(channel 1)
376	DIMM label, if set prior		(DIMM B1
377	and then an optional, driver-specific message that may
378		have additional information.
379
380Both UEs and CEs with no info will lack all but memory controller, error
381type, a notice of "no info" and then an optional, driver-specific error
382message.
383
384
385PCI Bus Parity Detection
386------------------------
387
388On Header Type 00 devices, the primary status is looked at for any
389parity error regardless of whether parity is enabled on the device or
390not. (The spec indicates parity is generated in some cases). On Header
391Type 01 bridges, the secondary status register is also looked at to see
392if parity occurred on the bus on the other side of the bridge.
393
394
395SYSFS CONFIGURATION
396-------------------
397
398Under /sys/devices/system/edac/pci are control and attribute files as follows:
399
400
401Enable/Disable PCI Parity checking control file:
402
403	'check_pci_parity'
404
405
406	This control file enables or disables the PCI Bus Parity scanning
407	operation. Writing a 1 to this file enables the scanning. Writing
408	a 0 to this file disables the scanning.
409
410	Enable:
411	echo "1" >/sys/devices/system/edac/pci/check_pci_parity
412
413	Disable:
414	echo "0" >/sys/devices/system/edac/pci/check_pci_parity
415
416
417Parity Count:
418
419	'pci_parity_count'
420
421	This attribute file will display the number of parity errors that
422	have been detected.
423
424
425
426MODULE PARAMETERS
427-----------------
428
429Panic on UE control file:
430
431	'edac_mc_panic_on_ue'
432
433	An uncorrectable error will cause a machine panic.  This is usually
434	desirable.  It is a bad idea to continue when an uncorrectable error
435	occurs - it is indeterminate what was uncorrected and the operating
436	system context might be so mangled that continuing will lead to further
437	corruption. If the kernel has MCE configured, then EDAC will never
438	notice the UE.
439
440	LOAD TIME: module/kernel parameter: edac_mc_panic_on_ue=[0|1]
441
442	RUN TIME:  echo "1" > /sys/module/edac_core/parameters/edac_mc_panic_on_ue
443
444
445Log UE control file:
446
447	'edac_mc_log_ue'
448
449	Generate kernel messages describing uncorrectable errors.  These errors
450	are reported through the system message log system.  UE statistics
451	will be accumulated even when UE logging is disabled.
452
453	LOAD TIME: module/kernel parameter: edac_mc_log_ue=[0|1]
454
455	RUN TIME: echo "1" > /sys/module/edac_core/parameters/edac_mc_log_ue
456
457
458Log CE control file:
459
460	'edac_mc_log_ce'
461
462	Generate kernel messages describing correctable errors.  These
463	errors are reported through the system message log system.
464	CE statistics will be accumulated even when CE logging is disabled.
465
466	LOAD TIME: module/kernel parameter: edac_mc_log_ce=[0|1]
467
468	RUN TIME: echo "1" > /sys/module/edac_core/parameters/edac_mc_log_ce
469
470
471Polling period control file:
472
473	'edac_mc_poll_msec'
474
475	The time period, in milliseconds, for polling for error information.
476	Too small a value wastes resources.  Too large a value might delay
477	necessary handling of errors and might loose valuable information for
478	locating the error.  1000 milliseconds (once each second) is the current
479	default. Systems which require all the bandwidth they can get, may
480	increase this.
481
482	LOAD TIME: module/kernel parameter: edac_mc_poll_msec=[0|1]
483
484	RUN TIME: echo "1000" > /sys/module/edac_core/parameters/edac_mc_poll_msec
485
486
487Panic on PCI PARITY Error:
488
489	'panic_on_pci_parity'
490
491
492	This control file enables or disables panicking when a parity
493	error has been detected.
494
495
496	module/kernel parameter: edac_panic_on_pci_pe=[0|1]
497
498	Enable:
499	echo "1" > /sys/module/edac_core/parameters/edac_panic_on_pci_pe
500
501	Disable:
502	echo "0" > /sys/module/edac_core/parameters/edac_panic_on_pci_pe
503
504
505
506EDAC device type
507----------------
508
509In the header file, edac_core.h, there is a series of edac_device structures
510and APIs for the EDAC_DEVICE.
511
512User space access to an edac_device is through the sysfs interface.
513
514At the location /sys/devices/system/edac (sysfs) new edac_device devices will
515appear.
516
517There is a three level tree beneath the above 'edac' directory. For example,
518the 'test_device_edac' device (found at the bluesmoke.sourceforget.net website)
519installs itself as:
520
521	/sys/devices/systm/edac/test-instance
522
523in this directory are various controls, a symlink and one or more 'instance'
524directories.
525
526The standard default controls are:
527
528	log_ce		boolean to log CE events
529	log_ue		boolean to log UE events
530	panic_on_ue	boolean to 'panic' the system if an UE is encountered
531			(default off, can be set true via startup script)
532	poll_msec	time period between POLL cycles for events
533
534The test_device_edac device adds at least one of its own custom control:
535
536	test_bits	which in the current test driver does nothing but
537			show how it is installed. A ported driver can
538			add one or more such controls and/or attributes
539			for specific uses.
540			One out-of-tree driver uses controls here to allow
541			for ERROR INJECTION operations to hardware
542			injection registers
543
544The symlink points to the 'struct dev' that is registered for this edac_device.
545
546INSTANCES
547---------
548
549One or more instance directories are present. For the 'test_device_edac' case:
550
551	test-instance0
552
553
554In this directory there are two default counter attributes, which are totals of
555counter in deeper subdirectories.
556
557	ce_count	total of CE events of subdirectories
558	ue_count	total of UE events of subdirectories
559
560BLOCKS
561------
562
563At the lowest directory level is the 'block' directory. There can be 0, 1
564or more blocks specified in each instance.
565
566	test-block0
567
568
569In this directory the default attributes are:
570
571	ce_count	which is counter of CE events for this 'block'
572			of hardware being monitored
573	ue_count	which is counter of UE events for this 'block'
574			of hardware being monitored
575
576
577The 'test_device_edac' device adds 4 attributes and 1 control:
578
579	test-block-bits-0	for every POLL cycle this counter
580				is incremented
581	test-block-bits-1	every 10 cycles, this counter is bumped once,
582				and test-block-bits-0 is set to 0
583	test-block-bits-2	every 100 cycles, this counter is bumped once,
584				and test-block-bits-1 is set to 0
585	test-block-bits-3	every 1000 cycles, this counter is bumped once,
586				and test-block-bits-2 is set to 0
587
588
589	reset-counters		writing ANY thing to this control will
590				reset all the above counters.
591
592
593Use of the 'test_device_edac' driver should enable any others to create their own
594unique drivers for their hardware systems.
595
596The 'test_device_edac' sample driver is located at the
597bluesmoke.sourceforge.net project site for EDAC.
598
599
600NEHALEM USAGE OF EDAC APIs
601--------------------------
602
603This chapter documents some EXPERIMENTAL mappings for EDAC API to handle
604Nehalem EDAC driver. They will likely be changed on future versions
605of the driver.
606
607Due to the way Nehalem exports Memory Controller data, some adjustments
608were done at i7core_edac driver. This chapter will cover those differences
609
6101) On Nehalem, there is one Memory Controller per Quick Patch Interconnect
611   (QPI). At the driver, the term "socket" means one QPI. This is
612   associated with a physical CPU socket.
613
614   Each MC have 3 physical read channels, 3 physical write channels and
615   3 logic channels. The driver currently sees it as just 3 channels.
616   Each channel can have up to 3 DIMMs.
617
618   The minimum known unity is DIMMs. There are no information about csrows.
619   As EDAC API maps the minimum unity is csrows, the driver sequentially
620   maps channel/dimm into different csrows.
621
622   For example, supposing the following layout:
623	Ch0 phy rd0, wr0 (0x063f4031): 2 ranks, UDIMMs
624	  dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
625	  dimm 1 1024 Mb offset: 4, bank: 8, rank: 1, row: 0x4000, col: 0x400
626        Ch1 phy rd1, wr1 (0x063f4031): 2 ranks, UDIMMs
627	  dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
628	Ch2 phy rd3, wr3 (0x063f4031): 2 ranks, UDIMMs
629	  dimm 0 1024 Mb offset: 0, bank: 8, rank: 1, row: 0x4000, col: 0x400
630   The driver will map it as:
631	csrow0: channel 0, dimm0
632	csrow1: channel 0, dimm1
633	csrow2: channel 1, dimm0
634	csrow3: channel 2, dimm0
635
636exports one
637   DIMM per csrow.
638
639   Each QPI is exported as a different memory controller.
640
6412) Nehalem MC has the ability to generate errors. The driver implements this
642   functionality via some error injection nodes:
643
644   For injecting a memory error, there are some sysfs nodes, under
645   /sys/devices/system/edac/mc/mc?/:
646
647   inject_addrmatch/*:
648      Controls the error injection mask register. It is possible to specify
649      several characteristics of the address to match an error code:
650         dimm = the affected dimm. Numbers are relative to a channel;
651         rank = the memory rank;
652         channel = the channel that will generate an error;
653         bank = the affected bank;
654         page = the page address;
655         column (or col) = the address column.
656      each of the above values can be set to "any" to match any valid value.
657
658      At driver init, all values are set to any.
659
660      For example, to generate an error at rank 1 of dimm 2, for any channel,
661      any bank, any page, any column:
662		echo 2 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/dimm
663		echo 1 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/rank
664
665	To return to the default behaviour of matching any, you can do:
666		echo any >/sys/devices/system/edac/mc/mc0/inject_addrmatch/dimm
667		echo any >/sys/devices/system/edac/mc/mc0/inject_addrmatch/rank
668
669   inject_eccmask:
670       specifies what bits will have troubles,
671
672   inject_section:
673       specifies what ECC cache section will get the error:
674		3 for both
675		2 for the highest
676		1 for the lowest
677
678   inject_type:
679       specifies the type of error, being a combination of the following bits:
680		bit 0 - repeat
681		bit 1 - ecc
682		bit 2 - parity
683
684       inject_enable starts the error generation when something different
685       than 0 is written.
686
687   All inject vars can be read. root permission is needed for write.
688
689   Datasheet states that the error will only be generated after a write on an
690   address that matches inject_addrmatch. It seems, however, that reading will
691   also produce an error.
692
693   For example, the following code will generate an error for any write access
694   at socket 0, on any DIMM/address on channel 2:
695
696   echo 2 >/sys/devices/system/edac/mc/mc0/inject_addrmatch/channel
697   echo 2 >/sys/devices/system/edac/mc/mc0/inject_type
698   echo 64 >/sys/devices/system/edac/mc/mc0/inject_eccmask
699   echo 3 >/sys/devices/system/edac/mc/mc0/inject_section
700   echo 1 >/sys/devices/system/edac/mc/mc0/inject_enable
701   dd if=/dev/mem of=/dev/null seek=16k bs=4k count=1 >& /dev/null
702
703   For socket 1, it is needed to replace "mc0" by "mc1" at the above
704   commands.
705
706   The generated error message will look like:
707
708   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))
709
7103) Nehalem specific Corrected Error memory counters
711
712   Nehalem have some registers to count memory errors. The driver uses those
713   registers to report Corrected Errors on devices with Registered Dimms.
714
715   However, those counters don't work with Unregistered Dimms. As the chipset
716   offers some counters that also work with UDIMMS (but with a worse level of
717   granularity than the default ones), the driver exposes those registers for
718   UDIMM memories.
719
720   They can be read by looking at the contents of all_channel_counts/
721
722   $ for i in /sys/devices/system/edac/mc/mc0/all_channel_counts/*; do echo $i; cat $i; done
723	/sys/devices/system/edac/mc/mc0/all_channel_counts/udimm0
724	0
725	/sys/devices/system/edac/mc/mc0/all_channel_counts/udimm1
726	0
727	/sys/devices/system/edac/mc/mc0/all_channel_counts/udimm2
728	0
729
730   What happens here is that errors on different csrows, but at the same
731   dimm number will increment the same counter.
732   So, in this memory mapping:
733	csrow0: channel 0, dimm0
734	csrow1: channel 0, dimm1
735	csrow2: channel 1, dimm0
736	csrow3: channel 2, dimm0
737   The hardware will increment udimm0 for an error at the first dimm at either
738	csrow0, csrow2  or csrow3;
739   The hardware will increment udimm1 for an error at the second dimm at either
740	csrow0, csrow2  or csrow3;
741   The hardware will increment udimm2 for an error at the third dimm at either
742	csrow0, csrow2  or csrow3;
743
7444) Standard error counters
745
746   The standard error counters are generated when an mcelog error is received
747   by the driver. Since, with udimm, this is counted by software, it is
748   possible that some errors could be lost. With rdimm's, they display the
749   contents of the registers
750
751AMD64_EDAC REFERENCE DOCUMENTS USED
752-----------------------------------
753amd64_edac module is based on the following documents
754(available from http://support.amd.com/en-us/search/tech-docs):
755
7561. Title:  BIOS and Kernel Developer's Guide for AMD Athlon 64 and AMD
757	   Opteron Processors
758   AMD publication #: 26094
759   Revision: 3.26
760   Link: http://support.amd.com/TechDocs/26094.PDF
761
7622. Title:  BIOS and Kernel Developer's Guide for AMD NPT Family 0Fh
763	   Processors
764   AMD publication #: 32559
765   Revision: 3.00
766   Issue Date: May 2006
767   Link: http://support.amd.com/TechDocs/32559.pdf
768
7693. Title:  BIOS and Kernel Developer's Guide (BKDG) For AMD Family 10h
770	   Processors
771   AMD publication #: 31116
772   Revision: 3.00
773   Issue Date: September 07, 2007
774   Link: http://support.amd.com/TechDocs/31116.pdf
775
7764. Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 15h
777	  Models 30h-3Fh Processors
778   AMD publication #: 49125
779   Revision: 3.06
780   Issue Date: 2/12/2015 (latest release)
781   Link: http://support.amd.com/TechDocs/49125_15h_Models_30h-3Fh_BKDG.pdf
782
7835. Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 15h
784	  Models 60h-6Fh Processors
785   AMD publication #: 50742
786   Revision: 3.01
787   Issue Date: 7/23/2015 (latest release)
788   Link: http://support.amd.com/TechDocs/50742_15h_Models_60h-6Fh_BKDG.pdf
789
7906. Title: BIOS and Kernel Developer's Guide (BKDG) for AMD Family 16h
791	  Models 00h-0Fh Processors
792   AMD publication #: 48751
793   Revision: 3.03
794   Issue Date: 2/23/2015 (latest release)
795   Link: http://support.amd.com/TechDocs/48751_16h_bkdg.pdf
796
797CREDITS:
798========
799
800Written by Doug Thompson <dougthompson@xmission.com>
8017 Dec 2005
80217 Jul 2007	Updated
803
804(c) Mauro Carvalho Chehab
80505 Aug 2009	Nehalem interface
806
807EDAC authors/maintainers:
808
809	Doug Thompson, Dave Jiang, Dave Peterson et al,
810	Mauro Carvalho Chehab
811	Borislav Petkov
812	original author: Thayne Harbaugh
813