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Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store de
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF |
Date: |
Wed, 27 Mar 2019 23:06:42 +1100 |
User-agent: |
Mutt/1.11.3 (2019-02-01) |
On Wed, Mar 27, 2019 at 10:44:03AM +0100, Greg Kurz wrote:
> On Wed, 27 Mar 2019 19:38:27 +1100
> David Gibson <address@hidden> wrote:
>
> > On Wed, Mar 27, 2019 at 08:09:26AM +0100, Greg Kurz wrote:
> > > On Wed, 27 Mar 2019 11:56:10 +1100
> > > David Gibson <address@hidden> wrote:
> > >
> > > > On Tue, Mar 26, 2019 at 08:09:53AM +0100, Greg Kurz wrote:
> > > > > On Tue, 26 Mar 2019 10:47:15 +1100
> > > > > David Gibson <address@hidden> wrote:
> > > > >
> > > > > > On Mon, Mar 25, 2019 at 05:33:21PM +0100, Greg Kurz wrote:
> > > > > > > On Mon, 25 Mar 2019 11:53:47 +1100
> > > > > > > David Gibson <address@hidden> wrote:
> > > > > > >
> > > > > > > > On Sun, Mar 24, 2019 at 12:03:54AM -0400, Brad Smith wrote:
> > > > > > > >
> > > > > > > > > Now that I am checking out 4.0.0 rc's I see this diff is
> > > > > > > > > broken and
> > > > > > > > > depends on a function libfdt does not expose. The breakage is
> > > > > > > > > hidden by the fallback check in the configure script.
> > > > > > > >
> > > > > > > > Ah, bother. That keeps happening, unfortunately. I think it's
> > > > > > > > because so many people use libfdt embedded, rather than as a
> > > > > > > > shared
> > > > > > > > library that we tend not to notice.
> > > > > > > >
> > > > > > >
> > > > > > > It's a bit more complicated. I do have latest libfdt packages on
> > > > > > > my laptop:
> > > > > > >
> > > > > > > libfdt-1.4.7-2.fc28.x86_64
> > > > > > > libfdt-devel-1.4.7-2.fc28.x86_64
> > > > > > >
> > > > > > > but I still end up using the embedded one and the build doesn't
> > > > > > > spot
> > > > > > > the missing symbols.
> > > > > >
> > > > > > Sorry, I wasn't clear. I wasn't meaning in the context of qemu, but
> > > > > > for dtc generally. A large portion of the users are things like
> > > > > > u-boot that have to use dtc embedded, rather than as a shared
> > > > > > library. That's why we tend not to notice missing symbols from the
> > > > > > version script upstream.
> > > > > >
> > > > >
> > > > > Ok, I get it.
> > > > >
> > > > > > > This happens because of several reasons:
> > > > > > >
> > > > > > > 1) configure unconditionally falls back to embedded if an error
> > > > > > > occurs with
> > > > > > > the system packages. And, as reported by Brad, the current
> > > > > > > 1.4.7 packages
> > > > > > > are broken indeed:
> > > > > > >
> > > > > > > $ objdump -T /usr/lib64/libfdt-1.4.7.so | grep fdt_check_full
> > > > > > > $
> > > > > > >
> > > > > > > 2) when building embedded, we only build the archive, not the
> > > > > > > shared lib.
> > > > > > >
> > > > > > > > I guess we should figure out how to force the testsuite to link
> > > > > > > > against the shared library rather than static to test for this.
> > > > > > > > I'll
> > > > > > > > look into it if I have time (which is a big if).
> > > > > > > >
> > > > > > >
> > > > > > > I think we should rather build the embedded shared library using
> > > > > > > the 'libfdt' rule of the top-level makefile of the dtc sub-module
> > > > > > > and have QEMU to be linked against this share library instead of
> > > > > > > the static one. AFAIK, this is what gcc does when it finds both
> > > > > > > .a and .so.
> > > > > >
> > > > > > Actually, I don't think this is a good idea. It means the resulting
> > > > > > qemu build would have to be installed with the libfdt image as well.
> > > > > > As well as complicating the install path, that means that the qemu
> > > > > > build will now actively conflict with a packaged libfdt, rather than
> > > > > > merely suboptimally failing to use it.
> > > > >
> > > > > Yes you're right: the resulting QEMU shouldn't be installed,
> > > > > especially
> > > > > if it has a RPATH poiting to the build directory.
> > > > >
> > > > > This being said, if someone wants to build AND install QEMU, shouldn't
> > > > > she rely exclusively on installed libfdt packages ? In other words,
> > > > > shouldn't the embedded libfdt be a QEMU developper only thing ? What
> > > > > are the real life use cases for embedded libfdt ?
> > > >
> > > > I don't think we should insist on that, although it's certainly the
> > > > way distros will usually work. If someone wants to build and install
> > > > qemu locally, I don't think we should insist they first work out how
> > > > to install a new enough libfdt for it to use.
> > > >
> > > > Likewise a limited purpose distro for whom qemu is the only user of
> > > > libfdt might not want to package it separately.
> > > >
> > >
> > > Fair enough. There's still one minor fix to make in configure for
> > > the tarball case though:
> > >
> > > # Not a git build & no libfdt found, prompt for system install
> > > error_exit "DTC (libfdt) version >= 1.4.2 not present." \
> > > "Please install the DTC (libfdt) devel package"
> > >
> > > Which version should that be ? Do you plan to release 1.5.0 or
> > > whatever anytime soon ?
> >
> > I released 1.5.0 about 3 weeks ago.
> >
>
> Hmm... I do see the version bumping patch in https://github.com/dgibson/dtc/
> but no trace of 1.5.0 in https://github.com/dgibson/dtc/releases... so
> I'm not sure if 1.5.0 is actually released. If it is released indeed, then
> I guess we need a 1.5.1 with the version.lds fix.
Looks like I forgot to push the tag to github. github is not the
primary site for dtc, just a mirror. The primary git tree is at
git://git.kernel.org/pub/scm/utils/dtc/dtc.git
and releases are at:
https://mirrors.edge.kernel.org/pub/software/utils/dtc/
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, (continued)
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, Brad Smith, 2019/03/24
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, David Gibson, 2019/03/25
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, Greg Kurz, 2019/03/25
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, Greg Kurz, 2019/03/25
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, David Gibson, 2019/03/25
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, Greg Kurz, 2019/03/26
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, David Gibson, 2019/03/27
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, Greg Kurz, 2019/03/27
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, David Gibson, 2019/03/27
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, Greg Kurz, 2019/03/27
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF,
David Gibson <=
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, Greg Kurz, 2019/03/27
- Re: [Qemu-ppc] [Qemu-devel] [PULL 02/29] ppc/spapr: Receive and store device tree blob from SLOF, David Gibson, 2019/03/27