On May 24, 2014, at 10:53 AM, Tijl Coosemans <t...@freebsd.org> wrote:
> On Sat, 24 May 2014 09:04:33 -0700 Nathan Whitehorn wrote: >> On 05/24/14 07:59, Tijl Coosemans wrote: >>> On Fri, 23 May 2014 17:29:48 -0600 Warner Losh wrote: >>>> On May 23, 2014, at 10:20 AM, Baptiste Daroussin <b...@freebsd.org> wrote: >>>>> On Fri, May 23, 2014 at 08:52:28AM -0700, Nathan Whitehorn wrote: >>>>>> On 05/23/14 08:36, Baptiste Daroussin wrote: >>>>>>> On Fri, May 23, 2014 at 08:19:34AM -0700, Nathan Whitehorn wrote: >>>>>>>> Is there any chance of finally switching the pkg abi identifiers to >>>>>>>> just >>>>>>>> be uname -p? >>>>>>>> -Nathan >>>>>>> Keeping asking won't make it happen, I have explained a large number of >>>>>>> time why it >>>>>>> happened, why it is not easy for compatibility and why uname -p is >>>>>>> still not >>>>>>> representing the ABI we do support, and what flexibility we need that >>>>>>> the >>>>>>> current string offers to us. >>>>>>> >>>>>>> if one is willing to do the work, please be my guess, just dig into the >>>>>>> archives >>>>>>> and join the pkg development otherwise: no it won't happen before a >>>>>>> while >>>>>>> because we have way too much work on the todo and this item is stored >>>>>>> at the >>>>>>> very end of this todo. >>>>>>> >>>>>>> regards, >>>>>>> Bapt >>>>>> I'm happy to do the work, and have volunteered now many times. If uname >>>>>> -p does not describe the ABI fully, then uname -p needs changes on the >>>>>> relevant platforms. Which are they? What extra flexibility does the >>>>>> string give you if uname -p describes the ABI completely? >>>>>> -Nathan >>>>> just simple examples in armv6: >>>>> - eabi vs oabi >>>>> - The different float abi (even if only one is supported for now others >>>>> are >>>>> being worked on) >>>>> - little endian vs big endian >>>> All of those are encoded in the MACHINE_ARCH + freebsd version, no >>>> exceptions >>>> on supported architectures that are tier 2 or higher. This seems like a >>>> weak reason. >>>> >>>>> the extras flexibilit is being able to say this binary do support freebsd >>>>> i386 >>>>> and amd64 in one key, freebsd:9:x86:*, or or all arches freebsd:10:* >>>> Will there be a program to convert this new, special invention to the >>>> standard >>>> that we’ve used for the past 20 years? If you need the flexibility, which >>>> I’m not >>>> entirely sure I’ve seen a good use case for. When would you have a x86 >>>> binary >>>> package? Wouldn’t it be either i386 or amd64? >>> ABI isn't just about the instruction set. It's also about the sizes of C >>> types (like pointers). If I remember correctly, the pkg scheme was chosen >>> to allow for ABIs like x32 which use the 64 bit instruction set with 32 >>> bit pointers. MACHINE_ARCH would also be amd64 in this case. >> >> No, it wouldn't. MACHINE_ARCH would be something else (x32, probably) in >> such cases. MACHINE_ARCH (and uname -p, which reports it) is the FreeBSD >> ABI identifier and encodes 100% of the ABI information. This would be >> true even if there is never an x32 kernel. > > No, there's no such thing as an x32 kernel. It's an amd64 kernel that > supports a second userland ABI. In C preprocessor terms they are > distinguished by (__amd64__ && _LP64) and (__amd64__ && !_LP64). > uname -p gives you the processor architecture (the __amd64__ bit) but > then you can still choose the sizes of standard C types (the _LP64 bit). > So far we've always had one ABI per processor architecture but this > is not strictly necessary. I think we’re talking past each other here. It absolutely would be MACHINE_ARCH == x32. That would be the name. And you could have an x32 kernel, if you wanted. When we’re building in the FreeBSD build system, we’d absolutely need a second MACHINE_ARCH. What you are doing here is confuse MACHINE_ARCH with MACHINE_CPUARCH. If you look at how we handle this for MIPS you’ll see we do exactly this for MIPS N32, which is exact likely x32. You don’t have to have a n32 kernel to run n32 binaries (but in MIPS’ case you can, if you want). Warner
signature.asc
Description: Message signed with OpenPGP using GPGMail
