Date: Thu, 17 Apr 2014 14:06:02 -0600 From: Warner Losh <imp@bsdimp.com> To: Mark R V Murray <mark@grondar.org> Cc: Tim Kientzle <tim@kientzle.com>, freebsd-arm <freebsd-arm@FreeBSD.org>, ticso@cicely.de, Ian Lepore <ian@FreeBSD.org> Subject: Re: Building an ARM/RPI-B release (hacked) on CURRENT/AMD64. Message-ID: <E0A43FC9-CBC9-4E6F-BDF1-B72C57145B3F@bsdimp.com> In-Reply-To: <54D788B2-BD68-4F75-86FF-0C4E71D9B75A@grondar.org> References: <9FDD6F0E-B2A9-48D9-A3E4-181868995FDA@grondar.org> <EC41E53F-96EF-4652-9A02-D49448D104BE@kientzle.com> <20140417103117.GE44138@cicely7.cicely.de> <1397738961.1124.157.camel@revolution.hippie.lan> <ED243420-AC33-4D90-A23D-0266C142F3C1@grondar.org> <1397761628.1124.245.camel@revolution.hippie.lan> <7196A020-54E1-42FA-B8A0-25B145B0E412@bsdimp.com> <54D788B2-BD68-4F75-86FF-0C4E71D9B75A@grondar.org>
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On Apr 17, 2014, at 1:54 PM, Mark R V Murray <mark@grondar.org> wrote: >=20 > On 17 Apr 2014, at 20:14, Warner Losh <imp@bsdimp.com> wrote: >=20 >>=20 >> On Apr 17, 2014, at 1:07 PM, Ian Lepore <ian@FreeBSD.org> wrote: >>>=20 >>> Hmmm. After a bit of poking around in the llvm code, it looks like = the >>> full extent of the support for -ffixed-r9 is that it doesn't = consider >>> that register available for use by the code generator; that's only = part >>> of what u-boot needs. =20 >>=20 >> what=92s the other part? Global register variables like this? >=20 > Yah. U-boot/Arm is heavily dependant on using R9 (previously R8) as a > global register variable. >=20 >>> Some online notes I found for clang 3.5 claim that global register >>> variables aren't supported, and aren't likely to be any time soon. >>=20 >> Is that a poke in the eye of uboot, or is it more of a contention = that >> uboot is moving away from that need? >=20 > It means that for now I guess we are stuck with using GCC to compile = u-boot. >=20 > I=92d mind a lot less if this was done as a port. >=20 > <thinking mode=3D=93aloud=94> > Hmm. A port to do what crochet does, without all the FreeBSD/ARM = (build|install)(world|kernel) stuff? >=20 > Something that makes an empty <mumble>.img (with only the weird boot = bits in it) as its =93product=94 for later use by the release process = might be nice. >=20 > I=92m guessing (more like hoping) that once the boot bits work, = they=92ll be pretty stable for a given platform for a while, and the = .img file could be kept under src/release/=85 somewhere. This way, it = doesn=92t matter if some humongous GCC port is used for cross-building; = this would be only needed when the boot-bits change. > <thinking> Ideally we=92d have it as a package which crochet could grab and use = rather than build from scratch. And the package should build with = whatever arm gcc we provide it with. Then crochet wouldn=92t need to = build xdev. It is really kinda abusing it as it is because xdev is = intended to be a fully functional cross compiler for FreeBSD/arm, not = just an arm cross compiler=85 Warner=
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