4 ms·

I feel uneasy giving up general purpose computing in the name of security. Can't we have both?

tomxor 8y ago
Yes but at a performance cost. I _think_ general purpose scalar processors lack any of the timing vulnerability since they almost literally do one thing at a time. But you are winding back the performance clock 1-2 decades - that's not to say they are unusable, for instance the arm core in the pi zero is scalar... but I doubt there is any modern desktop x86 equivalent without speculative execution.
- blattimwind 8y ago
  That ARM11 core is actually partially out of order (i.e. it issues in order, but permits out of order completion of independent insns) and has branch prediction.
- gpderetta 8y ago
  More like 4 decades. OoO itself is about three decades.
  - vardump 8y ago
    Yup. OoO is a thing from the mid-nineties for us mere mortals. CPUs like Pentium Pro and AMD K5. Of course the first out-of-order CPU is way older CDC 6600, back from 1964. MIPS R2000 from 1986 could do simple form of speculative execution.
AnIdiotOnTheNet 8y ago
Apparently not. The security twonks of the world would prefer we all get locked in cages and just consume the content we're fed (slowly as it passes through a hundred layers of abstraction each doing their own bounds checks and the likes). Specter and Meltdown are a great example of this, the community went ape over the whole thing introducing all sorts of slow-your-shit-down mitigations with a lot of people even suggesting that maybe we should ditch speculative execution entirely, for what? Because now there's a relatively high-effort way someone could exfiltrate data from my desktop via a browser? The only people who should have cared about Specter and Meltdown are hosting companies and people working in intelligence, and I would hope the latter have more reliable security practices that already take into account the possibility of things like Specter and Meltdown before they're even known about.

Yes but at a performance cost. I _think_ general purpose scalar processors lack any of the timing vulnerability since they almost literally do one thing at a time. But you are winding back the performance clock 1-2 decades - that's not to say they are unusable, for instance the arm core in the pi zero is scalar... but I doubt there is any modern desktop x86 equivalent without speculative execution.

blattimwind 8y ago
That ARM11 core is actually partially out of order (i.e. it issues in order, but permits out of order completion of independent insns) and has branch prediction.
gpderetta 8y ago
More like 4 decades. OoO itself is about three decades.
- vardump 8y ago
  Yup. OoO is a thing from the mid-nineties for us mere mortals. CPUs like Pentium Pro and AMD K5. Of course the first out-of-order CPU is way older CDC 6600, back from 1964. MIPS R2000 from 1986 could do simple form of speculative execution.

AnIdiotOnTheNet 8y ago

Apparently not. The security twonks of the world would prefer we all get locked in cages and just consume the content we're fed (slowly as it passes through a hundred layers of abstraction each doing their own bounds checks and the likes). Specter and Meltdown are a great example of this, the community went ape over the whole thing introducing all sorts of slow-your-shit-down mitigations with a lot of people even suggesting that maybe we should ditch speculative execution entirely, for what? Because now there's a relatively high-effort way someone could exfiltrate data from my desktop via a browser? The only people who should have cared about Specter and Meltdown are hosting companies and people working in intelligence, and I would hope the latter have more reliable security practices that already take into account the possibility of things like Specter and Meltdown before they're even known about.