Article now added !!! Preliminary, AS IS, no warranties... but USABLE imho.
Please contact me (yes, you, any you!) thru email, PM, or publicly in the forum, over technical inaccuracies, additions and so on.
Anyone is welcome to make simple corrections of form, grammar, formatting and the like as far as the software used for the knowledge base allows... Thank you!
http://www.woodmann.com/collaborative/knowledge/index.php/Super-secret_debug_capabilities_of_AMD_processors_!
Last edited by Czernobyl; November 11th, 2010 at 15:17. Reason: corrected URL
Looks nice Czernobyl.
I did some minot fixups in the text, as you requested.
Looking forward to more details about this!
"Give a man a quote from the FAQ, and he'll ignore it. Print the FAQ, shove it up his ass, kick him in the balls, DDoS his ass and kick/ban him, and the point usually gets through eventually."
Thanks! ... How do you add formatting at the Wiki, by the way ?Originally Posted by dELTA
Do you use HTML tags directly, or BBS-style tags, or something else ?
Yay, this is HUGE, I must stress : carries the power to create break conditions which otherwise were available only to owners of expensive hardware debuggers/ICEs, the price of which last time I checked would easily pay a dozen PCs...Looking forward to more details about this!
My expectation is word about this will spread and the expanded capabilities be added to existing debuggers (open and commercial). First let's check my assumption, that this is available in all newer AMD procs. This is a spell for you all to test your AMD-based computers for compliance. Do I need to provide a small program which checked for the existence of the expanded debug MSRs, or would that be an insult to those who hang out here !
There isn't actually any way to apply special formatting to the text of entries in the collaborative libraries. The recommended thing for more complex articles is rather to submit them as a PDF file, with a text introduction/preamble in the entry's text.
Yeah, you can say that again, your CRCEKL article was Slashdotted yesterday (http://hardware.slashdot.org/story/10/11/12/047243/Hidden-Debug-Mode-Found-In-AMD-Processors), which blew our entire server out of the water for 24 hours of so.
So, more people than you and me apparently agree that this is very cool, yes.
"Give a man a quote from the FAQ, and he'll ignore it. Print the FAQ, shove it up his ass, kick him in the balls, DDoS his ass and kick/ban him, and the point usually gets through eventually."
So is that what happened to the server.Couldn't get it to load the Forums for most of the day.
Regards,
JMI
If you'd have read your "special email account" a bit more often, you would have been informed about what was going on a long time ago.Anyway, let's not hijack this thread any more with that topic.
"Give a man a quote from the FAQ, and he'll ignore it. Print the FAQ, shove it up his ass, kick him in the balls, DDoS his ass and kick/ban him, and the point usually gets through eventually."
Wow! That slash-dot effect! Sorry for indirectly putting this site down for awhile, though in a way it's had the effect I secretly hoped - I mean of course not crashing woodmann.com, but, this is all over the web now! Just google "Czernobyl + AMD"A plume of fame for this site and for my persona indeed : "an intrepid Polish (or Ukrainian?) hacker". Ha,ha! I can't help thinking how the late Fravia would have made fun of all the nonsense that's being spread, useless alarms about (non existent, AFAICT) security implications.
Why no, I'm waiting for you all to do your homework while me goes to rest - in particular, please check for the functions I have disclosed in as representative as possible a sample of AMD procs. I did the work on one lowly Sempron 2400+ (Thoroughbred die). Why do you think I chose /this/ board for unleashing my cute little findings ? What are you waiting for ? Go test /your/ AMDs !Anyway, let's not hijack this thread any more with that topic.
Cheers
--
Czerno
Czerno:
dELTA was suggesting he and I not hijack the thread to talk about my not checking my email.
Regards.
JMI
I grasped as much; what I'm wondering is why this thread is not (yet) being overflowed with all your test results. I chose this board to air my little bomb - out of a thousand places - because I believed that here, at least, it would meet with enthusiastic testers. Let me not be disappointed, the spirit of Fravia is blowing still isn't it ?
It's really not a tough matter to check for the debugctlmsr2 etc. features. Do people want to be spoon-fed a test program ? I didn't propse to write one out of respect for this community members ! I'll tell you a secret : perso, I do most of the quick and dirty tests under good old DOS debug (or rather the Freedos version, now maintained by Japheth). Just change some IDT vectors (at the minimum, 06 and the 0Dh one- GPF) so they point to Debug's routine for int3, and you can test the most arcane processor bits in less time than it costs to recount the results :=)
But whatever method you best like, go test and report results here for deity's sake !
Maybe we're all using Intel these days! (That's my excuse, at least...)
That's my excuse, too.
My last AMD was a K7. Never missed it dreadfully.
I have a slight dislike for AMD. Guess it's since they took over ATI.
Interesting reading, though.
Intel here as well. I too had a bad experience with an AMD processor several years ago and have been an Intel user since.
Yeah, Intel for years and years...
I guess a test program (preferably "open source" though, to avoid paranoia) might help you get more results from the few people who use AMD today anyway.
"Give a man a quote from the FAQ, and he'll ignore it. Print the FAQ, shove it up his ass, kick him in the balls, DDoS his ass and kick/ban him, and the point usually gets through eventually."
You may be right, people might want to be spoon fed nowadays. Well, I shall make a small test program, time allowing, only don't hold your breath : I'm busy with other priorities ATM
well... I have several AMD CPU's, I think that I might do some tests on that. However I never did a low level reverse engineering. But I think that i have enough knowledge to do at least some tests.
I have some AMD Athlon/Sempron and a Phenom XII (mayble useless). maybe there will be a Athlon 64 X2 but I'm not sure.
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