Hasn’t Ken Shirriff been doing this for quite a while? (:->
Can you reverse engineer an ASIC?
51–60 of 89 posts
Re: Can you reverse engineer an ASIC?
#52Hasn’t Ken Shirriff been doing this for quite a while? (:->
I'm too busy trying to reverse-engineer the Intel 8087 floating-point chip, although it would be interesting to look at this puzzle chip.
Re: Can you reverse engineer an ASIC?
#53Man, these guys always have insane puzzles. What the heck.
Re: Can you reverse engineer an ASIC?
#54I wrote a guide for newbies to learn
Re: Can you reverse engineer an ASIC?
#55What prerequisites I need to solve this puzzle? I don't have much knowledge in electrical engineering.
It’s hard without some basic knowledge maybe this can help https://siliconzoo.org/tutorial.html
Re: Can you reverse engineer an ASIC?
#56At my uni, 15 years ago, one postdoc reverse engineered NVIDIA chip and wrote more performant compiler. He did that by connecting oscyloscops to all chip's outputs and started with applying random current on inputs. Using ML and his genius he rediscoverd all opcodes including a few hidden ones. Eventually he got hired by some company that was doing a lot of GPU on supercomputers.
There is absolutely no way that happened. 15 years ago, we're talking Fermi class GPUs and chips with hundreds of millions of bits of on-chip state and much more if you include the DRAM. You can't tease out the right information by applying random inputs. Which input would you even use? The PCIe interface? You'd first "randomly" need to get past its complex training sequences... Your postdoc probably wrote micro-benc…
You might is they included DFT (design for test, stuff to make sure when you make a chip all of it actually works) - a scan chain thru all the internal flops will provide you with info about the internal flops and how they are connected - reverse engineering this into a model of reality would certainly be extremely hard, but maybe not impossible
Re: Can you reverse engineer an ASIC?
#57Earlier quoted context omitted.
There is absolutely no way that happened. 15 years ago, we're talking Fermi class GPUs and chips with hundreds of millions of bits of on-chip state and much more if you include the DRAM. You can't tease out the right information by applying random inputs. Which input would you even use? The PCIe interface? You'd first "randomly" need to get past its complex training sequences... Your postdoc probably wrote micro-benc…
You might is they included DFT (design for test, stuff to make sure when you make a chip all of it actually works) - a scan chain thru all the internal flops will provide you with info about the internal flops and how they are connected - reverse engineering this into a model of reality would certainly be extremely hard, but maybe not impossible
While that's theoretically possible, it's even harder than trying to do it over, say, PCIe, because the latter at least still has a higher meaning to it while scan chain FFs are just grouped based on spatial proximity.
And of course that's assuming that a) the JTAG port is accessible on these boards and b) the raw scan chain access before scan chain compression hasn't been fused off or isn't locked behind some authentication protocol.
So, no. That didn't happen either. :-)
Re: Can you reverse engineer an ASIC?
#58At my uni, 15 years ago, one postdoc reverse engineered NVIDIA chip and wrote more performant compiler. He did that by connecting oscyloscops to all chip's outputs and started with applying random current on inputs. Using ML and his genius he rediscoverd all opcodes including a few hidden ones. Eventually he got hired by some company that was doing a lot of GPU on supercomputers.
> He did that by connecting oscyloscops to all chip's outputs and started with applying random current on inputs This is absolutely not how reverse engineering a digital logic ASIC works. Either the story got embellished through retellings, or this person was a fantasist. There are people who hack on GPUs but it’s done at the software level. I did get a kick out of imagining a scene where someone is trying to connect…
Many laymen confuse logic analyzers with oscilloscopes. Don't take it personally - the person you responded to is clearly not a native English speaker.
You absolutely can reverse chips with logic analysis. It is big business in some parts of the world.
Re: Can you reverse engineer an ASIC?
#59Earlier quoted context omitted.
There is absolutely no way that happened. 15 years ago, we're talking Fermi class GPUs and chips with hundreds of millions of bits of on-chip state and much more if you include the DRAM. You can't tease out the right information by applying random inputs. Which input would you even use? The PCIe interface? You'd first "randomly" need to get past its complex training sequences... Your postdoc probably wrote micro-benc…
And you don't use an o-scope in anycase, since you'd need...what...a thousand of them to watch all the signals. You'd use a logic analyzer. I think I read somewhere that those older nvidia chips had something like 2000 BGA balls, and Tektronix does make an LA that can scale to 2000-something channels (TLA7000), for a modest US$500k or so. Then you gotta figure how to mount the thing to attach the probes. So...agreed.…
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Re: Can you reverse engineer an ASIC?
#60At my uni, 15 years ago, one postdoc reverse engineered NVIDIA chip and wrote more performant compiler. He did that by connecting oscyloscops to all chip's outputs and started with applying random current on inputs. Using ML and his genius he rediscoverd all opcodes including a few hidden ones. Eventually he got hired by some company that was doing a lot of GPU on supercomputers.
> He did that by connecting oscyloscops to all chip's outputs and started with applying random current on inputs This is absolutely not how reverse engineering a digital logic ASIC works. Either the story got embellished through retellings, or this person was a fantasist. There are people who hack on GPUs but it’s done at the software level. I did get a kick out of imagining a scene where someone is trying to connect…
Thank you for taking your time to squash another potential "urban legend" in the making. We've got enough of them already in tech.