From: "Vincenzo Palazzo" <vincenzopalazzodev@gmail.com>
To: "Andrea Righi" <andrea.righi@canonical.com>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: <rust-for-linux@vger.kernel.org>
Subject: Re: distribute linux-headers to build out-of-tree Rust modules
Date: Sun, 12 Mar 2023 14:39:20 +0100 [thread overview]
Message-ID: <CR4G3AY4U6IJ.2ZRJBDCGH9Z0Q@vincent-arch> (raw)
In-Reply-To: <ZAzedS9sx5l6gmzB@righiandr-XPS-13-7390>
On Sat Mar 11, 2023 at 9:03 PM CET, Andrea Righi wrote:
> On Sat, Mar 11, 2023 at 04:27:52PM +0000, Björn Roy Baron wrote:
> > On Saturday, March 11th, 2023 at 15:01, Andrea Righi <andrea.righi@canonical.com> wrote:
> >
> > > Hello,
> > >
> > > I'm trying to distribute a linux-headers package (deb) that would allow
> > > to build out-of-tree Rust modules.
> > >
> > > Everything looks fine, except for the following error:
> > >
> > > error[E0461]: couldn't find crate `core` with expected target triple target-10951614936105594995
> > > |
> > > = note: the following crate versions were found:
> > > crate `core`, target triple target-3759196539525232825: /usr/src/linux-headers-6.2.0-16-generic/rust/libcore.rmeta
> > >
> > > All I need to do is to "refresh" the headers by running a
> > > "make modules_prepare" after installing my linux-headers package on my
> > > system and then everything works perfectly.
> > >
> > > Is this because my system, where I try to build the out-of-tree module,
> > > has different toolchain versions (e.g., binutils) than the build host?
> > >
> > > Any pointer/documentation to better understand how the target triple
> > > version is determined?
> >
> > The target id for external targets should be determined based on the filename and the hash of the target specification json file since https://github.com/rust-lang/rust/pull/98225. That it happens to work with "make modules_prepare" may be that it recompiles all rust code for the new target triple and through luck it just so happens to have the exact same abi as the original. There is no guarantee that two compiled rust crates have the same abi unless they have the exact same contents. To debug why the target id changed could you try running the following rust program in both the linux source dir and the /usr/src/linux-headers-6.2.0-16-generic dir?
>
> $ pwd
> /usr/src/linux-headers-6.2.0-16-generic
> $ ./test
> 5559158138856098584
>
> $ pwd
> /home/ubuntu/src/linux
> $ ./test
> 5559158138856098584
>
> ^ Same hash, but at this point I think we already know that the problem
> is the patch above that I'm missing in rustc.
Maybe we should increase the compiler version required by rust in the
kernel?
Cheers!
Vincent.
next prev parent reply other threads:[~2023-03-12 13:39 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-11 14:01 distribute linux-headers to build out-of-tree Rust modules Andrea Righi
2023-03-11 14:51 ` Geert Stappers
2023-03-11 16:27 ` Björn Roy Baron
2023-03-11 20:03 ` Andrea Righi
2023-03-12 13:39 ` Vincenzo Palazzo [this message]
2023-03-12 22:08 ` Andrea Righi
2023-03-13 1:35 ` Miguel Ojeda
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