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>"One of the most interesting members of the RISC-style x86 group was the Transmeta Crusoe processor, which translated x86 instructions into an internal VLIW fo
by peter_d_sherman 6y ago
>"One of the most interesting members of the RISC-style x86 group was the Transmeta Crusoe processor, which translated x86 instructions into an internal VLIW form, rather than internal superscalar, and used software to do the translation at runtime, much like a Java virtual machine. This approach allowed the processor itself to be a simple VLIW, without the complex x86 decoding and register-renaming hardware of decoupled x86 designs, and without any superscalar dispatch or OOO logic either."
PDS: Why do I bet that the Transmeta Crusoe didn't suffer from Spectre -- or any other other x86 cache-based or microcode-based security vulnerabilities that are so prevalent today?
Observation: Intentional hardware backdoors -- would have been difficult to place in Transmeta VLIW processors -- at least in the software-based x86 translation portions of it... Now, are there intentional hardware backdoors in its lower-level VLIW instructions?
I don't know and can't speculate on that...
Nor do I know if the Transmeta Crusoes contained secret deeply embedded "security" cores/processors -- or not...
But secret deeply embedded "security" cores/processors and backdoored VLIW instructions aside -- it would sure be hard as heck for the usual "powers-that-be" -- to be able to create secret/undocumented x86 instructions with side effects/covert communication to lower/secret levels -- and run that code from the Transmeta Crusoe's x86 software interpreter/translator -- especially if the code for the x86 software interpreter/translator -- is open source and throughly reviewed...
In other words, from a pro-security perspective -- there's a lot to be said about architecturally simpler CPU's -- regardless of how slow they might be compared to some of today's super-complex (and, ahem, less secure...) CPU's...
- detaro 6y agoAFAIK Transmeta's core was doing a lot of speculative execution stuff, so if it evolved until today I wouldn't bet on it also gaining issues like Spectre.
- peter_d_sherman 6y agoIt would be an interesting test, wouldn't it? See if Transmeta Crusoe is vulnerable to Spectre? But, even if it is... keep in mind that when running x86 instructions, you still have the x86 translation software proxy layer... that means that could could grab any given offending / problem-causing x86 instruction -- when you encountered it, and recode the VLIW output from it to output a different set of native VLIW instructions -- that you knew were safe... In other words, with a Transmeta Crusoe -- if the x86 translation layer is open source and you possess it (and can code / understand things) -- then you'll have some options there. Which is unlike a regular x86 CPU -- where the way it decodes and executes instructions -- cannot be changed in any way by the user...
- detaro 6y agoTransmeta Crusoe is unlikely to be vulnerable, but it's Intel contemporaries aren't either. So you'd need to be looking at some hypothetical "today" version. An open system with such a design would indeed be fascinating (the original wasn't open, and Transmeta was big on their patents on this stuff). More flexibility than microcode patches too.
- peter_d_sherman 6y ago>An open system with such a design would indeed be fascinating Agreed completely! >More flexibility than microcode patches too Agreed completely!
- ruslan 6y agoElbrus 2000 is a mass-produced VLIW microprocessor with binary translation of x86. There is a set of different models having different number of cores and DSP blocks. https://en.wikipedia.org/wiki/Elbrus_2000 https://en.wikipedia.org/wiki/Elbrus_2000
- monocasa 6y agoThe code morphing software itself is almost certainly a new source of new side channel spectre like attacks. Like being able to tell if something is already in the translation cache via timing.
- mhh__ 6y agoIt would be much easier for a vendor to turn off speculative compilation in that case though, i.e. for HPC you want all the performance, but a cloud vendor could still protect vulnerable interfaces.
- monocasa 6y agoThe compilation doesn't need to be speculative. It'd be a lot like the micro op cache attack that was on the front page not too long ago. The point is to leak privileged code flow.
- ruslan 6y agoSome consider E2K (Elbrus 2000) as successor to Transmeta Crusoe and it is not effected to Spectre issue. It does binary translation of x86 code as well and quite fast (20% preformance loss).
- peter_d_sherman 6y agoFascinating! Did not know that Elbrus continued on the same technology path as Transmeta! Here, let's put a link for posterity: https://en.wikipedia.org/wiki/Elbrus_2000 https://en.wikipedia.org/wiki/Elbrus_2000 PDS: Opinion: Transmeta/Elbrus/VLIW designs in general -- worthy of future study...
- bsder 6y agoAny speculation with any shared hardware is a no-no from a security standpoint. You can either separate your hardware (physically or virtually) or do no speculation.