1 2 Previous Next 26 Replies Latest reply on Apr 30, 2016 2:39 PM by cresquin

    Edison 64-bit kernel

    Roman_Ts

      Hi,

       

      Intel Edision has 64-bit CPU on the board (48-bit addressing && lm flag in /proc/cpuinfo).

      Is there any x86_64 or even better x32 images for this device?

      How to build 64-bit kernel using Yocto Linux tools?

       

      Thanks!

        • 1. Re: Edison 64-bit kernel
          deium

          Roman_Ts

          Although I haven't created my own custom image for the Edison yet, the Intel Edison Board Support Package that goes over creating a custom image does show that one can choose a 64 bit kernel in the section Customizing the Linux Kernel.  That BSP document can be found here: Intel® Edison BSP User Guide

          The process of customizing your Edison image (as per the BSP) outlines how to add and remove packages for the image as well.

           

          There is a Debian Wheezy (stable) based ubilinux image that you can find discussed here.  https://communities.intel.com/message/256964#256964

           

          • 2. Re: Edison 64-bit kernel
            AlexT_Intel

            Out of curiosity - why would you need one? There's only a gig of RAM anyway. And I'm not 100% sure, but I was under impression it should be 32-bit core, even though flags may say otherwise (which could be just a phantom of the SoCs previous life).

            • 3. Re: Edison 64-bit kernel
              deium

              AlexT_Intel, is it really _not_ a 64 bit core?  I was kind of going by what is advertised in the flags?  I thought the Atom was always 64 bit?

              Appreciating that there is a difference in 64 bit and Intel_64 instruction set.

              • 4. Re: Edison 64-bit kernel
                deium

                Roman_Ts

                The Board Support Guide Intel® Edison BSP User Guide, Section 4, Figure 2 on Page 11 clearly shows a 64 bit kernel option in the configuration section.

                • 5. Re: Edison 64-bit kernel
                  AlexT_Intel

                  Not all Atoms are 64 bit (example list).

                   

                  I don't have any other information about this core than in the public docs.

                  And the Edison Compute Module HW Guide says it's IA-32 core (page 10, section 3.1). On the other hand, we see that flag reported by Linux and the same HW guide says it's Atom Z34xx core.There are only two processors in this family reported by ARK and both are 64-bit, however none of them matches the one used in Edison, it uses a heavily modified version of that SoC as far as I understand, so we can't just assume it's going to have the same features as those models listed in ARK. Other documents in the Documentation section of the community (like Product Brief and the IDF presentation) don't specifically mention bitness of the Atom core.

                   

                  So at the end of the day, IMHO it's either a 32bit core with 64 bit features switched off in such a way that flag is still there, but actual 64bitness doesn't work (artifact from the past I mentioned earlier), or it's actually a 64bit one, but for whatever reason that bitness is not supported right now (all the toolchains and Yocto configs for Edison are 32bit). After all, it only has 1GB of RAM and enabling 64bit won't give any real benefit as far as can think of.

                  • 6. Re: Edison 64-bit kernel
                    deium

                    AlexT_Intel,

                    Thanks for the info, I feel I have been schooled.   We could then also use ARK to check that 22nm and 32-bit reveals no subset.

                    To quote Dire Straights (Industrial Disease) "Two men say their Jesus, one of them must be wrong"  So one, both, or all of the documents are incorrect.

                    If it is a new class, such as the Quark, why is it not listed and classified "Edison".

                    • 7. Re: Edison 64-bit kernel
                      AlexT_Intel

                      If you mean schooling  in this sense then I was nowhere near that when writing the above Actually I was puzzled by that too as I haven't looked at the cpuinfo flags on Edison and I always believed it's unquestionably 32bit based on that information I saw previosly, so I did some research to understand what's going on. Not much came out as we can see, but I guess that's probably the same thing as with other documentation - it's just a bit behind the actual product and it will be fixed at some point in the future.

                      • 8. Re: Edison 64-bit kernel
                        deium

                          I wasn't thinking Urban dictionary, but of an episode of the Big Bang.  I noted that on a preboot sequence of the board that fails to provide the ota drive, Windows Device manager identified the Edison as Merrifield   -- and the z3460 Merrifield was 64 bit as by ARK, however, if the provided Intel support is for the 32 bit Yocto os, with 32 bit libraries -- I could see where documenting as 32 bit.  If it was stated as 64, then support would need to be simultaneous 32 and 64.

                         

                        How do we see what became of the z3460 - I noted that ARK does not list it with a tray price and refers to it as Formerly Merrifield with no suppliers listing the z3460

                        • 9. Re: Edison 64-bit kernel
                          anomaly256

                          AlexT_Intel wrote:

                          I don't have any other information about this core than in the public docs.

                          We need more public docs, specifically low-level stuff, if Intel expect us to create and invent using this new platform.  I think you can appreciate that 'is it really 32bit or is it 64bit' and

                          'are those cpu flags really supported' are important questions that software developers need to know if they are looking to implement anything closer to bare metal (and they will, because a 10~15 second bootup time isn't acceptable for consumer appliances).  I'm sure they're being worked on and I'm sure the delay is due to the definition of the platform still being somewhat in flux but the sooner the better

                          After all, it only has 1GB of RAM and enabling 64bit won't give any real benefit as far as can think of.

                          There is an advantage to using a 64bit kernel with a 32bit userland - kernel code gets access to more, wider, registers and extended instructions, while application code remains small and memory-efficient.  As far as I know this is the optimal configuration for a 64bit platform with less than 4gb physical memory. There are also applications that could be compelling on the Edison that are only available in 64bit environments despite not requiring > 4gb physical memory (docker maybe?  A stretch I know but such things do exist).

                          • 10. Re: Edison 64-bit kernel
                            deium

                            anomaly256,

                            You know the neat thing about the Edison is that it uses the same Intel instructions that have been around for years.  If we want to get to the bare metal without sulfur, we grab your assembler at the command console and tap it out.  Intel does provide us with the same massive 7 volume instruction set and guide that has been on the website for years.  If you are good at 64 bit assembly, we'd be able to go through all the flags and test the associated instructions - then we'd know.  First we have to port a 64 bit kernel - which I am sure bitbake and the source code provided could give our own insights.

                             

                            So, the low level stuff is here (my copy of the seven volumes still downloading)   the Merrifield specs ARK | Intel® Atom™ Processor Z3460 (1M Cache, up to 1.60 GHz), for the included quark ARK | Intel® Quark™ SoC X1000 (16K Cache, 400 MHz)

                            • 11. Re: Edison 64-bit kernel
                              anomaly256

                              deium,

                              Well that is assuming it *is* 64bit, which Intel can't even confirm for us yet.  Hence the need for more public docs specific to this SoC.

                              • 12. Re: Edison 64-bit kernel
                                anomaly256

                                Not to mention docs regarding how to talk to the Quark core from the Atom core!

                                • 13. Re: Edison 64-bit kernel
                                  deium

                                  Windows identified my Edison as a Merrifield - that is the z3460 - the ARK shows that was a 64 bit dual core.

                                  Intel may have a new name - good enough for me.  The Quark specs are posted.  Now, I agree, I am waiting for docs as well

                                  on addresses, peripherals, how do we access etc - but I am certain it is the intel programming we've been use too.

                                  • 14. Re: Edison 64-bit kernel
                                    arfoll

                                    Just see /proc/cpuinfo, it shows 'lm' in the flags which is long mode. I'm not usually one to believe the cpuid instruction lie so this is 64bit chip.

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