Hello wonderful people! I'm bunnie - just noticed this is on HN. Unfortunately due to timezones I'm about to afk for a bit. I'll check back when I can, and try to answer questions that accumulate here.
I'd assume the point is that they think that the possibility of serving the website to an individual physically within a prohibited country constitutes unacceptable liability.
Wait a minute, why can't I reply to bunnie's top-level comment? Anyway, here's what I wanted to say:
Adding your CPU to another company's silicon is a genius move, well done. I wonder why companies don't sell their spare die space to others, is it because of trust/risk?
Crossbar is unusual to start with in that they wanted to do open RTL - so for starters, there's to a first order no companies even willing to discuss open RTL designs. Beyond that - mainly risk. I had to pinky swear that whatever I added would not break the chip, cause timing closure issues, delay the schedule, consume too much area or power, impact yield, I had to run my own validation and review program while meeting their dev methodology, etc. etc. I had to exercise an enormous amount of self-restraint to not push harder and do more interesting things as it was. It's very hard to build up inter-personal trust, and they had to take a calculated risk letting a schmuck like me potentially foul up a multi-million dollar mask set. Hats off to them for making that bold decision, it would have been easier to say nope, too risky, no benefit, cut it from the code base.
I'm basically ignorant of this entire space--I have mostly worked on SaaS products--so please forgive the question if it's too naive but as (the first?) someone who has just experienced this new and rare way of bringing a design to life are there any obvious process/tooling/whatever improvements you noticed that might make it less risky (and therefore less rare)? Reading your blog posts, the crowd supply materials, Xous docs, etc the burning thought at the front of my mind has been "there needs to be a lot more of this". Is there a path towards that?
There's actually a whole space of shared-mask tapeouts. You might have heard of TinyTapeout [1]/LibreLane [2] and the general concept of "MPW" masks - multi-project wafer masks. These effectively share cost among hundreds of developers, bringing the cost of a tape-out down.
If you're lucky enough to have an affiliation with certain institutions, there are programs that basically give academics the experience I had for a nominal fee. TSMC has a finfet program [3] which powers Soclabs [4] to provide an environment that exceeds Baochip's capabilities. If you look through [4] notice the block that says "Users' HW circuits" - that's basically what my logic is on Baochip. The problem with these is you need to be academic and I think there isn't a clear path to commercialization, and of course lots of NDAs. China also has a program called "One Student One Chip" [5] where students can tape out quite sophisticated SoCs as part of their course work.
It's probably just a matter of time before these academic programs yield a commercially compelling chip, and then that would pave a path for a transition program from the academic program to industry.
Another option is, if Baochip is quite successful, it in itself could serve as a "proof point" that may encourage other companies to allow hitchhikers. When the co-designed IP works, then it's a sales upside for the company, so there is some incentive alignment.
The trick is figuring out how to mitigate the possibility that the IP doesn't work, and bridging the gap between people with ideas and people with tape-out experience. I'm lucky in that in my first jobs out of college I did a deep dive into silicon, even designing custom transistor and standard cells for a bespoke nanophotonics PDK that I helped to develop, so I had the shared language to communicate with both classic chip companies and open source community.
There's an enormous cultural gap between the chip community and the open source community, but everyone's curiosity in this thread and participating in this dialog with questions like yours helps close that gap and thus manifest more hitchhiking opportunities in the future.
Having paid for multi-million dollar mask sets for ASICs before, I can confirm that this would take a lot of trust on Crossbar’s side. Great job on working with them.
Yeah, true, it's all downside for them for this, basically. Still, there must be some price for which companies will let other companies use die space, but maybe that price is higher than just doing the thing yourself...
In the space of possibilities this can be abstractly thought of as a Caravell [1] harness gone wild. But if you had to price access to the project in a commercial sense, then, the pricing is going to be quite high. Because it's not just the cost of the masks - there's a whole lot of talent and skill in the team that does the "backend" processing. That is, once the RTL is done, it goes through multiple passes of place/route/timing, ATPG, DRC, LVS...and that's just to get to the tape-out. After that there's still more to do with the chip probe, packaging and reeling.
The open-source argument is that if we could make that back-end part more transparent, then, we could improve the tooling and thus decrease the labor. But, even a single mistake at these backend steps can scuttle a whole mask set. The methodology is incredibly incremental, scripts are handed down for generations and there are magic settings in them that make things "just work" and nobody quite remembers why or how but it was probably a lesson learned the hard way so we just leave it that way. And it's not just the money - the iteration time through a fab is months. So you have to be a bit careful about prioritizing your experiments and your risk budget when trying to make progress in this field.
I am lucky in my case because what I want to do aligns with their original commercial interests, so the strategic benefit makes things worth the tactical risk. Frankly a big part of the project overall was just figuring out how to scope things so that we both came away reasonably satisfied in terms of risk and outcomes. Would I like things to be more open? yes. would I liked to have put an opentitan core in there? yes. Would I have been able to take advantage of more back-end support to do a faster CPU? yes. But, we had to constantly balance tactical risks, and even if I don't agree with all their decisions, I have to respect their experience.
> Those with a bit of silicon savvy would note that it’s not cheap to produce such a chip, yet, I have not raised a dollar of venture capital. I’m also not independently wealthy. So how is this possible?
What kind of order of magnitude of cost are we talking about?
What are the next steps - is there some service to cut the wafer and put into a package for you?
The masks alone are single digit millions, but with all the design tools and staff costs typically tens of millions is the benchmark number for a tape out in this node.
After coming out of the fab, the chips go through probing, packaging and reeling.
Yes, exactly. A lot depends on your expected volume. Essentially, masks are your fixed tooling cost for chips. You then amortize that over your full volume. It’s easier to justify another mask set to fix bugs if you are going to be selling oodles of chips and the cost ends up being negligible and much harder to justify it if the volume is low. Years ago, I was CTO at a startup when our chips came back from fab. Everything looked good except for a silly error that our chief architect had made. He felt horrible for a couple weeks. He was a great architect (meticulous and precise) and I kept telling him that it was no use crying over spilled milk. Engineering is hard. But there went another few million dollars of precious venture capital up in smoke for the replacement mask sets.
Rule of thumb is that a processed wafer from 28nm and older is around $3k/wafer and the cost goes up kind of exponentially towards the smaller nodes. Also, in general, the fab wants you to order a "FOUP" of wafers at a time - that's 25 wafers at a go.
This is wonderful! Also what a fantastic partnership that allowed adding a new CPU to that die. Kudos to them.
I had a lot of trouble finding out which open source license applies. Wikipedia’s RISC-V page doesn’t seem to say; its citation for being released under open source doesn’t seem to say which one either.[0] Could be wrong. Exhausted after working all day. But it’s not front and center…
On the RISC-V site I thought it might be more prominent too but if it is I missed it. I found some docs there licensed Creative Commons. Is that the license for the entire CPU? Even layouts and everything that is past the ISA to actual silicon?
bunnie your book "Hacking the XBox" taught me how to get started on reversing electronics, took the fear out of the process, and replaced it with fun. Thanks for the multi-decades long effort you've made to make these tools available and accessible and approachable, your contributions to the hacker community are immeasurable and I cannot say thank you enough.
> What’s a banker going to do with the source code of a chip, anyway?
Hand it to someone who does know what to do with it. It's not as important who initially gets the source so much as having it available when it is needed.
Great work on the chip, I’m really onboard with the trusted computing aim!
Is there a way to bootstrap binary code into the reram? I’m thinking being able to ‘hand-type’ in a few hundred byte kernel rather than use a flashing tool
> If the pen tester doing a security evaluation judges that a bug is easier to find and exploit if the source code is public, then, sharing the source code lowers your score
Good on the author for calling out how nuts this is! In the age of LLM coding agents, I feel this mentality needs to change quickly. Security through obscurity is dead. LLMs have little to no issues conversing in encoded or obfuscated data.
I didn't know there were partially open source RISC-V. I might have missed it in the article, but what was the reason for having some parts closed source?
MMU's have held sway for nearly 60 years, but I wonder if in ten years time when the AI is the whole stack/runs the whole stack and the majority of us wont be running anything but prompts they will be required. I have a big interest in how the AI will penetrate into the hardware level, not just as a sci-fi fan/author but as an electronics engineer/programmer. I should add that I doubt AI hardware will penetrate much into the embedded market due to cost.
A bit sad to see another famous hacker turning to the "dark side" --- as "security chips" are a treacherous slippery slope, no matter who controls them. Just because it's "open source" doesn't mean it's a good thing.
Edit: give Stallman's "Right to Read" another read.
79 comments
*edit, Crowdsupply does a full block on multiple VPN providers. There is no way to access their site without turning off your VPN.
> few individuals relying on snake oil security
Please don't.
I'm not saying it's totally unrelated, only that there do have a dedicated non technical but legal check.
Adding your CPU to another company's silicon is a genius move, well done. I wonder why companies don't sell their spare die space to others, is it because of trust/risk?
If you're lucky enough to have an affiliation with certain institutions, there are programs that basically give academics the experience I had for a nominal fee. TSMC has a finfet program [3] which powers Soclabs [4] to provide an environment that exceeds Baochip's capabilities. If you look through [4] notice the block that says "Users' HW circuits" - that's basically what my logic is on Baochip. The problem with these is you need to be academic and I think there isn't a clear path to commercialization, and of course lots of NDAs. China also has a program called "One Student One Chip" [5] where students can tape out quite sophisticated SoCs as part of their course work.
It's probably just a matter of time before these academic programs yield a commercially compelling chip, and then that would pave a path for a transition program from the academic program to industry.
Another option is, if Baochip is quite successful, it in itself could serve as a "proof point" that may encourage other companies to allow hitchhikers. When the co-designed IP works, then it's a sales upside for the company, so there is some incentive alignment.
The trick is figuring out how to mitigate the possibility that the IP doesn't work, and bridging the gap between people with ideas and people with tape-out experience. I'm lucky in that in my first jobs out of college I did a deep dive into silicon, even designing custom transistor and standard cells for a bespoke nanophotonics PDK that I helped to develop, so I had the shared language to communicate with both classic chip companies and open source community.
There's an enormous cultural gap between the chip community and the open source community, but everyone's curiosity in this thread and participating in this dialog with questions like yours helps close that gap and thus manifest more hitchhiking opportunities in the future.
[1] https://tinytapeout.com/
[2] https://github.com/librelane/librelane
[3] https://www.tsmc.com/english/dedicatedFoundry/services/unive...
[4] https://soclabs.org/project/tsri-arm-cortex-m55-aiot-soc-des...
[5] https://ysyx.oscc.cc/en/project/intro.html
The open-source argument is that if we could make that back-end part more transparent, then, we could improve the tooling and thus decrease the labor. But, even a single mistake at these backend steps can scuttle a whole mask set. The methodology is incredibly incremental, scripts are handed down for generations and there are magic settings in them that make things "just work" and nobody quite remembers why or how but it was probably a lesson learned the hard way so we just leave it that way. And it's not just the money - the iteration time through a fab is months. So you have to be a bit careful about prioritizing your experiments and your risk budget when trying to make progress in this field.
I am lucky in my case because what I want to do aligns with their original commercial interests, so the strategic benefit makes things worth the tactical risk. Frankly a big part of the project overall was just figuring out how to scope things so that we both came away reasonably satisfied in terms of risk and outcomes. Would I like things to be more open? yes. would I liked to have put an opentitan core in there? yes. Would I have been able to take advantage of more back-end support to do a faster CPU? yes. But, we had to constantly balance tactical risks, and even if I don't agree with all their decisions, I have to respect their experience.
[1] https://github.com/efabless/caravel
> Wait a minute, why can't I reply to bunnie's top-level comment?
The powers that be here think they've found a bunch of "hacks" to curb off low quality comments.
> Those with a bit of silicon savvy would note that it’s not cheap to produce such a chip, yet, I have not raised a dollar of venture capital. I’m also not independently wealthy. So how is this possible?
What kind of order of magnitude of cost are we talking about?
What are the next steps - is there some service to cut the wafer and put into a package for you?
After coming out of the fab, the chips go through probing, packaging and reeling.
> The masks alone are single digit millions,
Ah, another reason why hardware erratas get fixed so rarely (I assume - along with retesting of course).
I had a lot of trouble finding out which open source license applies. Wikipedia’s RISC-V page doesn’t seem to say; its citation for being released under open source doesn’t seem to say which one either.[0] Could be wrong. Exhausted after working all day. But it’s not front and center…
On the RISC-V site I thought it might be more prominent too but if it is I missed it. I found some docs there licensed Creative Commons. Is that the license for the entire CPU? Even layouts and everything that is past the ISA to actual silicon?
[0] https://www.extremetech.com/computing/188405-risc-rides-agai...
Thanks man!
https://www.youtube.com/watch?v=H5CR-7TJtm0
> What’s a banker going to do with the source code of a chip, anyway?
Hand it to someone who does know what to do with it. It's not as important who initially gets the source so much as having it available when it is needed.
Is there a way to bootstrap binary code into the reram? I’m thinking being able to ‘hand-type’ in a few hundred byte kernel rather than use a flashing tool
Is it big Bao? Or take-away (just learnt the second meaning), or something else?
> If the pen tester doing a security evaluation judges that a bug is easier to find and exploit if the source code is public, then, sharing the source code lowers your score
Good on the author for calling out how nuts this is! In the age of LLM coding agents, I feel this mentality needs to change quickly. Security through obscurity is dead. LLMs have little to no issues conversing in encoded or obfuscated data.
Thank you Bunnie.
I'm also curious about the current draw, but I couldn't find anything?
Big fan of this project by the way.
Edit: give Stallman's "Right to Read" another read.