Date: Tue, 16 Jun 2015 23:48:53 +1030 From: Michael Vale <m.vale@live.com.au> To: Adrian Chadd <adrian@freebsd.org>, Warner Losh <imp@bsdimp.com> Cc: "freebsd-embedded@freebsd.org" <embedded@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: RE: Starting to cross-compile non-base software for MIPS - what it's like Message-ID: <COL130-W1459933AF469DF96988866C4A70@phx.gbl> In-Reply-To: <CAJ-Vmo=8oyyWiRBS9EU%2BKicz_jm90gO46cu_QRu9Az2RHU7zRw@mail.gmail.com> References: <CAJ-VmonSXYdLP_VpGh%2B3N_WfGwDLqWGcuPvOCf4VkOd0pJ5QWg@mail.gmail.com>, <B29CEB72-367C-4295-BD93-2A5C417D0553@bsdimp.com>, <CAJ-Vmo=8oyyWiRBS9EU%2BKicz_jm90gO46cu_QRu9Az2RHU7zRw@mail.gmail.com>
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Here is onething that can be added under .if defined(X_BUILD_FOR)=2C either=
as an .include e.g. bsd.cross.mk. or just paste it in there. if X_BUILD_F=
OR /is/ defined=2C configure --host mips-freebsd-* etc will already be done=
if you just invoke a normal ports build rather than running configure manu=
ally from port/work/.
=20
I know it's not perfect=2C but the only thing that needs and overview is th=
e declaration of SYSROOT. I used ${LOCALBASE} to define the right position=
=2C i'm unsure if this is correct.
=20
---------------------------- bsd.cross.mk ---------------------------------=
-------------------------------------------
=20
.if exist(/usr/${X_BUILD_FOR}/usr/bin/${X_BUILD_FOR}-portbld-freebsd11.0-gc=
c) then \
MAKE_ENV+=3D CPU_ARGS=3D"-march=3D${X_BUILD_FOR}"
INCS=3D"-l${SRCDIR}/../root/${X_BUILD_FOR}
.else
IGNORE=3D Install gcc with mips support from ports first.
.if FLOAT=3D"hard" then \
MAKE_ENV+=3D CPU_ARGS=3D"-mhard-float=2C -Wa=2C-mhard-float"
.else \
MAKE_ENV+=3D CPU_ARGS=3D"-msoft-float=2C -Wa=2C-msoft-float"
MAKE_ENV+=3D CROSS_COMPILE=3D"${X_BUILD_FOR}-portbld-freebsd${OS_REL} \
CC=3D${CROSS_COMPILE}-gcc \
CXX=3D${CROSS_COMPILE}-g++ \
LD=3D${X_BUILD_FOR}-freebsd-ld \
AR=3D${X_BUILD_FOR}-freebsd-ar \
RANLIB=3D${X_BUILD_FOR}-freebsd-ranlib \
STRIP=3D${X_BUILD_FOR}-freebsd-strip \
SYSROOT=3D${LOCALBASE}/${X_BUILD_FOR}/ \
CFLAGS=3D"--sysroot=3D$SYSROOT ${CPU_ARGS} ${INCS} -O"
CXXFLAGS=3D"--sysroot=3D$SYSROOM ${CPU_ARGS} ${INCS} -O"
=20
> Date: Mon=2C 15 Jun 2015 11:45:00 -0700
> Subject: Re: Starting to cross-compile non-base software for MIPS - what =
it's like
> From: adrian@freebsd.org
> To: imp@bsdimp.com
> CC: embedded@freebsd.org=3B freebsd-mips@freebsd.org
>=20
> On 15 June 2015 at 10:23=2C Warner Losh <imp@bsdimp.com> wrote:
> >
> >> On Jun 14=2C 2015=2C at 1:13 PM=2C Adrian Chadd <adrian@freebsd.org> w=
rote:
> >>
> >> Hi!
> >>
> >> I've been hacking at cross compiling things on FreeBSD for a while=2C
> >> and I have made some progress. This email is less of a "how you can do
> >> it" and more of a "these are the roadblocks that prevent it from
> >> working out of the box."
> >>
> >> I'm using gcc-4.9.2 from ports - there's a cross compiler for
> >> mips/mips64=2C and there's mips-binutils/mips64-binutils. I'm using
> >> those to compile world and kernel. The kernel works=3B world requires
> >> some patching to compile. I'll write a post when I have a complete
> >> system booting/running from gcc-4.9.2.
> >>
> >> My test application is dropbear. Ie=2C I'm cross-compiling dropbear fo=
r
> >> mips from freebsd/i386.
> >>
> >> * There are some issues in libgcc - I have a patch that I've emailed
> >> out for review. I'll do some more testing and commit it next week when
> >> I know it works.
> >> * There are some environment variables that need to be set before I
> >> compile dropbear. Here's what it looks like:
> >>
> >> CPU_ARGS=3D"-march=3Dmips32 -msoft-float -Wa=2C-msoft-float"
> >> INCS=3D"-I/home/adrian/work/freebsd/head-embedded-2/root/mips/usr/incl=
ude"
> >>
> >> export CROSS_COMPILE=3Dmips-portbld-freebsd11.0
> >> export CC=3D${CROSS_COMPILE}-gcc
> >> export CXX=3D${CROSS_COMPILE}-g++
> >> #export LD=3D${CROSS_COMPILE}-ld
> >> #export AR=3D${CROSS_COMPILE}-ar
> >> #export RANLIB=3D${CROSS_COMPILE}-ranlib
> >> #export STRIP=3D${CROSS_COMPILE}-strip
> >> export LD=3Dmips-freebsd-l
> >> export AR=3Dmips-freebsd-ar
> >> export RANLIB=3Dmips-freebsd-ranlib
> >> export STRIP=3Dmips-freebsd-strip
> >> export SYSROOT=3D/home/adrian/work/freebsd/head-embedded-2/root/mips/
> >> export CFLAGS=3D"--sysroot=3D$SYSROOT ${CPU_ARGS} ${INCS} -O"
> >> export CXXFLAGS=3D"--sysroot=3D$SYSROOT ${CPU_ARGS} ${INCS} -O"
> >> export CPPFLAGS=3D"--sysroot=3D$SYSROOT ${CPU_ARGS} ${INCS} -O"
> >> export LDFLAGS=3D--sysroot=3D$SYSROOT
> >>
> >> # now run:
> >> # /configure --host=3Dmips-portbld-freebsd11.0
> >> # gmake
> >>
> >> ... then I hit a problem with how we populate links in /usr/lib and
> >> such. TL=3BDR - the symlinks we use are not relative paths=2C they're
> >> absolute paths - and this makes cross building using sysroot /
> >> explicit library paths fail to work right. Sigh. In particular=2C I
> >> needed to manually undo the libgcc symlink for it to compile.
> >> compilation complained about other libraries=2C but the resulting
> >> binaries did run.
> >
> > That=92s one of about 6 reasons that what we produce isn=92t a
> > sysroot. We need to create a sysroot target that=92s very close
> > to the xdev targets with all the compiler bits stripped out. We=92re
> > close though. I have about 1/2 of the patch needed to remove
> > xdev entirely and replace it with sysroot.
>=20
> Sweet.
>=20
> > You shouldn=92t need the INCS args if you have a proper sysroot.
> > And the CPU_ARGS is an indication we=92re building our port
> > incorrectly. This is the same feedback I gave on the kernel
> > make changes you suggested.
>=20
> It looks like a proper sysroot - I think it's just the dynamic sysroot
> stuff being broken.
>=20
> > I=92ve had hacks like this for =93simple=94 arts for years. It=92s why =
I wrote
> > xdev in the first place. I had it working in the FreeBSD 6 time frame
> > for cross building some ports. But once you get past a certain
> > class of very well behaved ports=2C it goes to hell in a hurry.
>=20
>=20
> >> * I'll try to wrangle juli/bsdimp to review the kernel changes needed
> >> to compile up the kernel with gcc-4.9.
> >
> > I=92ve already reviewed that one. gcc isn=92t being compiled correctly
> > and that need to be fixed. This is the forth time I=92ve given this
> > feedback.
>=20
> There are some other issues too. The softfloat/hardfloat stuff reared
> its head - in order to avoid assembler warnings we have to manually
> set it=2C but then the floating point register accesses in fp.S /
> swtch.S generate errors. I've worked around that for now=2C but I need
> to dig into why the warnings are generated in the first case.
>=20
> >> * I'd like some help / comments on what we can do about the absolute
> >> symlinks used for various things inside an installed root. Ideally
> >> we'd have an option that would let us populate only relative links -
> >> that'd instantly make this problem go away.
> >
> > All installworld-ish targets should use relative path symbolic links.
> > The fact they are using absolute paths is a bug. In the FreeBSD 6
> > time frame=2C I fought this battle at work and it wasn=92t hard to fix.=
I
> > no longer have access to those sources=2C and I honestly can=92t
> > recall how I fixed it (it may have been in a post-processing
> > step).
>=20
> I'd love to get this fixed and into the tree.
>=20
> >> * I'll go hit up bapt and some netbsd friends for some help with
> >> expected sysroot behaviour on gcc/binutils. It's possible there are
> >> still bugs with the dynamic sysroot (ie=2C when you don't compile your
> >> toolchain with an explicit sysroot to something other than '/') that
> >> need addressing.
> >
> > bapt and I have been talking about this for a while. We=92ve both been
> > busy doing other things so haven=92t focused on it other than in off
> > moments.
> >
> >> Then I'll worry about starting to convert a few ports to be native
> >> cross building.
> >
> > You should talk to bapt about the rather extensive work he=92s done
> > in this area=2C which is why I=92ve looked at transitioning the xdev
> > support to just sysroot support.
>=20
> I have been too! fear not. That's how I got this far!
>=20
>=20
> -a
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