On Tue, Mar 26, 2019 at 08:09:53AM +0100, Greg Kurz wrote: > On Tue, 26 Mar 2019 10:47:15 +1100 > David Gibson <da...@gibson.dropbear.id.au> 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 <da...@gibson.dropbear.id.au> 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.
--
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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