Date: Sat, 24 May 2014 17:53:09 -0600 From: Warner Losh <imp@bsdimp.com> To: Tijl Coosemans <tijl@freebsd.org> Cc: Baptiste Daroussin <bapt@freebsd.org>, src-committers@freebsd.org, Ian Lepore <ian@freebsd.org>, svn-src-all@freebsd.org, Glen Barber <gjb@freebsd.org>, Nathan Whitehorn <nwhitehorn@freebsd.org>, svn-src-head@freebsd.org Subject: Re: svn commit: r266553 - head/release/scripts Message-ID: <3CCAFAD3-FABE-40EF-ABF9-815FE5826349@bsdimp.com> In-Reply-To: <20140525011307.142b41ab@kalimero.tijl.coosemans.org> References: <201405221922.s4MJM4Y9025265@svn.freebsd.org> <537F6706.6070509@freebsd.org> <20140523153619.GF72340@ivaldir.etoilebsd.net> <537F6EBC.3080008@freebsd.org> <20140523162020.GG72340@ivaldir.etoilebsd.net> <C5A59513-AF58-4749-BCD7-F54BB6F56E90@gmail.com> <20140524165940.3c687553@kalimero.tijl.coosemans.org> <5380C311.60201@freebsd.org> <20140524185345.263f230d@kalimero.tijl.coosemans.org> <1400955835.1152.323.camel@revolution.hippie.lan> <5380EBA8.1030200@freebsd.org> <20140525011307.142b41ab@kalimero.tijl.coosemans.org>
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--Apple-Mail=_02A95910-71D2-41B1-B1EA-81D13A907F81 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-7 On May 24, 2014, at 5:13 PM, Tijl Coosemans <tijl@freebsd.org> wrote: > On Sat, 24 May 2014 11:57:44 -0700 Nathan Whitehorn wrote: >> On 05/24/14 11:23, Ian Lepore wrote: >>> On Sat, 2014-05-24 at 18:53 +0200, Tijl Coosemans 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 = <bapt@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. >>>>>>>>>>=20 >>>>>>>>>> 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. >>>>>>>>>>=20 >>>>>>>>>> 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. >>>>>>>=20 >>>>>>>> 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=A2ve used for the past 20 years? If you need the = flexibility, which I=A2m not >>>>>>> entirely sure I=A2ve seen a good use case for. When would you = have a x86 binary >>>>>>> package? Wouldn=A2t 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. >>>=20 >>> All you have to do is look at the plethora of ARM ABIs we support = (and >>> the corresponding separate kernel for each) to see the falseness of = that >>> last sentence. ARM variations include v4 vs v6, OABI vs EABI = (calling >>> and register usage standards), hard vs soft float, little vs big = endian. >>> Virtually all combinations of those are possible (there are a few = combos >>> we don't support), and each one has its own MACHINE_ARCH. >>=20 >> Exactly. This doesn't rely on the kernel either. The hw.machine_arch=20= >> sysctl (what uname -p returns) gives the ABI of the calling binary=20 >> rather than the kernel. So if you use a 32-bit uname (e.g. in a = chroot)=20 >> on an amd64 host, you get i386. The same will be true if and when we=20= >> support a 32-bit amd64 userland -- even if there is no x32 kernel, an=20= >> x32 uname will return "x32" (or "amd32" or whatever it ends up being=20= >> called). That string will also appear in kern.supported_archs. >=20 > There isn't necessarily any chroot environment. There's one kernel, > two equally valid ABIs (ILP32 and LP64) and any binary like uname = might > use either of them. If uname -p returns a different result depending = on > which of these two ABIs it was compiled for that could be a problem = for > any script that uses it. Well, it depends on what you want to do with the script, eh? If you want = to know the ABI of the native binary uname, that=A2s one thing. But if = you want to know the supported ABIs, you are doing it wrong by using = uname. You should be using sysctl kern.supported_abi. That will tell you = all the ABIs that you can install packages for on this machine, which is = what you really want to know. So I=A2m having trouble connecting the = dots between this and what you are saying here. I still am absolutely flabbergasted why the MACHINE_ARCH names aren=A2t = necessary and sufficient for packaging. I=A2ve yet to see any coherent = reason to not use them. Warner --Apple-Mail=_02A95910-71D2-41B1-B1EA-81D13A907F81 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJTgTDlAAoJEGwc0Sh9sBEA/0YP+wff0BgZzV3tZYQiP0qp6b3I wlxdKCDQZRh0p7fcKc9+44iVkyCCzuZv0Gk97j5Y3sDZNIu5oU5uwR0X9Nsbt/Rp stbDMbv36fPsM6Kj7C07Ugb5ElN9gH/UulO9Vm3RqCL1tZJO35w/MXWwBDzZHZw8 TySBj2WUaSaFmgYGLmBv2X6sJJfEmYMl9GcC2TUpdEPfNLu5xNgDECmuO9uOmbSh aRO5pFRnprWkwWfv0PuXrBBkVJevgcWzq5euylIVfs85XTNmNugflJzQfYXiI5qx GBnJbXgI6B95qFIg37g95zKI35Ny591jy9X2oYpinYNxlhv2pRFjFlJD+liWtB0z Wpp7OnaWO1FxpQS+lSaqbjNPrJ9eLTpNMMenwXEU567t5w9P4pRjAUW/o8eFqbCj wHiRaaRAIJ5qEewF8sW33975gRufMy64ASnXCosz5RUG9wDTcXlQ5G+JiGwMo9BA 5fuEHlkHzpWZ3sCV4PfOYqWUH0Dy6YbZ74gfXI92QbyCq/4/TANG85fNC8DzZ14e FgE5WqhRzrBVJmoFFW+lQly/YV2i2Akh8xt3WqDEhPmppMCQ3uA0fGK4n7PXNmIK 2hc/E+qbMMoImT3sQ9rfVXanTCXoHdGNt+G06/C8b5d9jseElQuvuWUFeqCYq6iC TAy0uy04ejLfGBFICSb/ =Xm3M -----END PGP SIGNATURE----- --Apple-Mail=_02A95910-71D2-41B1-B1EA-81D13A907F81--
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