On Sun, Nov 5, 2023 at 6:12 AM Martin Rodriguez Reboredo <yakoyoku@xxxxxxxxx> wrote: > > This RFC provides makes possible to have bindings for kernel subsystems > that are compiled as modules. > > Previously, if you wanted to have Rust bindings for a subsystem, like > AMBA for example, you had to put it under `rust/kernel/` so it came > part of the `kernel` crate, but this came with many downsides. Namely > if you compiled said subsystem as a module you've a dependency on it > from `kernel`, which is linked directly on `vmlinux`. > > So instead of overpopulating `kernel` with a gazillion modules that > throws you into dire straits you should rather have the bindings in the > same directory as the subsystem you want to bind with and link it to > it. > > With this patch Rust sources can be compiled into libraries for them to > be consumed. These libraries are ar archives that follow the `.rlib` > structure, namely a libfoo.rlib thin archive with a foo.foo.o object > and a libfoo.rmeta rustc metadata as members. Such Rust crates get > their symbols exposed and the `bindings` crate is made available for > them. > > Also included there's a sample usage of this in another patch, but it > is not meant to be merged as it remains as an example. > > If you want to use a crate with your Rust module just add a `rust-libs` > variable in your Makefile with a value of the relative directory of > said crate plus its name, e.g. > > # Link with the foo crate > rust-libs += ../path/to/foo I will not provide a line-by-line review. Just one thing I'd like to point out. You assume the library (drivers/usb/core/*) is built before its consumers (samples/rust/*). If Kbuild ends up with building lib consumers first, it will be a build error. Kbuild descends into multiple directories in parallel building. You cannot predict which directory is built first. > Martin Rodriguez Reboredo (2): > kbuild: Build Rust crates as libraries > samples: rust: Add USB sample bindings > > .gitignore | 2 ++ > Makefile | 4 ++-- > drivers/usb/core/Kconfig | 7 ++++++ > drivers/usb/core/Makefile | 3 +++ > drivers/usb/core/usb.rs | 13 ++++++++++ > rust/bindings/bindings_helper.h | 1 + > samples/rust/Kconfig | 10 ++++++++ > samples/rust/Makefile | 3 +++ > samples/rust/rust_usb_simple.rs | 22 +++++++++++++++++ > scripts/Makefile.build | 42 ++++++++++++++++++++++++++++++--- > scripts/Makefile.lib | 20 ++++++++++++---- > scripts/Makefile.modfinal | 9 +++++-- > 12 files changed, 125 insertions(+), 11 deletions(-) > create mode 100644 drivers/usb/core/usb.rs > create mode 100644 samples/rust/rust_usb_simple.rs > > -- > 2.42.1 > -- Best Regards Masahiro Yamada
