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The silicon - the rest of the logic that makes the CPU - isn't. There's more to CPUs than microcode. Besides, how can you audit that the open source microcode i

The silicon - the rest of the logic that makes the CPU - isn't. There's more to CPUs than microcode. Besides, how can you audit that the open source microcode is what the manufacturer actually put into the CPU? Microcode is usually ROM-based with only runtime patches. Open source microcode does not change the fact that you need to trust the CPU manufacturer not to backdoor your CPU. There is literally no way around that that does not involve using FPGAs and restricting yourself to 100MHz CPUs. By the way, I googled POWER9 microcode and was not able to find any source or reference to it. The source code for the firmware running on various auxiliary cores is open source. However, the CPU cores do contain microcode for executing more complex instructions, and I am not finding any reference to this being open source.

nix23 5y ago
I understand that you have problems reading so i repeat it for you the third time: >>>since you cannot check the silicon... And since you have problems using google too: https://www.sbir.gov/node/1620879 https://www.sbir.gov/node/1620879 >>A small business has already shown that a completely open source solution (to include CPU firmware, CPU Microcode, Baseboard Management Controller (BMC), BIOS boot code, power management, etc.) based on a high performance CPU is possible. Imagine who that "small business" is?
- marcan_42 5y ago
  Where's the link to the source? FYI, IBM loves to use the term "microcode" to include side CPU firmware and such. This is different from Intel "microcode" which strictly refers to the instruction dispatch part. Is the instruction dispatch microcode in POWER9 open source or not? None of these are it: https://wiki.raptorcs.com/wiki/OpenPOWER_Firmware https://wiki.raptorcs.com/wiki/OpenPOWER_Firmware
  - nix23 5y ago
    https://git.raptorcs.com/git/ https://git.raptorcs.com/git/ >>CPU Internal Firmware >>CPU External Firmware
    - marcan_42 5y ago
      SBE, OCC, HCODE. Those are from the list I linked. None of them are the instruction dispatch microcode. Maybe it's time for you to have the realization that POWER9 has proprietary microcode just like Intel. At least it seems they probably have less of it, and they do vaguely document it in the CPU manual (they have micro-op classes and counts) but it's there, and I don't see any real source code anywhere. They also have patch registers, so you can't even say it's not updatable. The POWER9 manual mentions six Instruction Mask Registers per core, but these registers are documented nowhere (I just spent a good 30 minutes digging through the giant register documentation PDFs and HCODE source, but I couldn't find anything). Is this better than Intel? Yes. Is it "fully free"? No. Nothing's fully free. Which is why we need nuanced analysis, not the nonsense arbitrary lines the FSF draws in the sand.

nix23 5y ago

I understand that you have problems reading so i repeat it for you the third time: >>>since you cannot check the silicon... And since you have problems using google too: https://www.sbir.gov/node/1620879 https://www.sbir.gov/node/1620879 >>A small business has already shown that a completely open source solution (to include CPU firmware, CPU Microcode, Baseboard Management Controller (BMC), BIOS boot code, power management, etc.) based on a high performance CPU is possible. Imagine who that "small business" is?

marcan_42 5y ago
Where's the link to the source? FYI, IBM loves to use the term "microcode" to include side CPU firmware and such. This is different from Intel "microcode" which strictly refers to the instruction dispatch part. Is the instruction dispatch microcode in POWER9 open source or not? None of these are it: https://wiki.raptorcs.com/wiki/OpenPOWER_Firmware https://wiki.raptorcs.com/wiki/OpenPOWER_Firmware
- nix23 5y ago
  https://git.raptorcs.com/git/ https://git.raptorcs.com/git/ >>CPU Internal Firmware >>CPU External Firmware
  - marcan_42 5y ago
    SBE, OCC, HCODE. Those are from the list I linked. None of them are the instruction dispatch microcode. Maybe it's time for you to have the realization that POWER9 has proprietary microcode just like Intel. At least it seems they probably have less of it, and they do vaguely document it in the CPU manual (they have micro-op classes and counts) but it's there, and I don't see any real source code anywhere. They also have patch registers, so you can't even say it's not updatable. The POWER9 manual mentions six Instruction Mask Registers per core, but these registers are documented nowhere (I just spent a good 30 minutes digging through the giant register documentation PDFs and HCODE source, but I couldn't find anything). Is this better than Intel? Yes. Is it "fully free"? No. Nothing's fully free. Which is why we need nuanced analysis, not the nonsense arbitrary lines the FSF draws in the sand.