Date: Thu, 17 Apr 2014 21:10:29 -0700 From: Tim Kientzle <tim@kientzle.com> To: Mark R V Murray <mark@grondar.org> Cc: freebsd-arm <freebsd-arm@FreeBSD.org>, Ian Lepore <ian@FreeBSD.org>, ticso@cicely.de Subject: Re: Building an ARM/RPI-B release (hacked) on CURRENT/AMD64. Message-ID: <1963F059-91A1-4D4C-84AE-7BC6C25044E1@kientzle.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 12:54 PM, Mark R V Murray <mark@grondar.org> wrote: > > On 17 Apr 2014, at 20:14, Warner Losh <imp@bsdimp.com> wrote: > >> >> On Apr 17, 2014, at 1:07 PM, Ian Lepore <ian@FreeBSD.org> wrote: >>> >>> 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. >> >> what’s the other part? Global register variables like this? > > Yah. U-boot/Arm is heavily dependant on using R9 (previously R8) as a > global register variable. > >>> 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. >> >> Is that a poke in the eye of uboot, or is it more of a contention that >> uboot is moving away from that need? > > It means that for now I guess we are stuck with using GCC to compile u-boot. Unless you can find some other way to make the ‘gd’ symbol return the value of r9. Hmmm…. How good is clang’s inline assembly? #define gd __asm(…. return r9 … ) Or maybe: #define gd getr9() gd_t *getr9(void); > I’d mind a lot less if this was done as a port. > > <thinking mode=“aloud”> > Hmm. A port to do what crochet does, without all the FreeBSD/ARM (build|install)(world|kernel) stuff? > > Something that makes an empty <mumble>.img (with only the weird boot bits in it) as its “product” for later use by the release process might be nice. /usr/ports/sysutils/u-boot-beaglebone-eabi is looking for an owner. ;-) This was my attempt to do essentially what you suggest, but I never got it quite working. There are experimental bits in Crochet to exploit this port if it’s been “installed” on the system. (“Install” in this case installs the built U-Boot bits in /usr/local/share and puts a shell script in /usr/local/bin that can copy those bits to a specified target dir.) Timhelp
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