[PATCH 00/13] Support several Rust toolchain versions

[PATCH 00/13] Support several Rust toolchain versions

[Miguel Ojeda]

Hi all,

It is time to start supporting several Rust toolchain versions and thus
establish a minimum Rust compiler and `bindgen` version.

For the Rust compiler, we will start with a window of two stable
releases, and widen it over time. This series keeps the minimum where
it is (1.78.0), but adds support for the recently released 1.79.0.

This should already be enough for kernel developers in distributions that
provide recent Rust compiler versions routinely, such as Arch Linux,
Debian Unstable (outside the freeze period), Fedora Linux, Gentoo
Linux (especially the testing channel), Nix (unstable) and openSUSE
Tumbleweed. A documentation adds the instructions for each of them.

In addition, Rust for Linux is now being built-tested in Rust's
pre-merge CI. That is, every change that is attempting to land into the
Rust compiler is tested against the kernel, and it is merged only if it
passes -- thanks to the Rust project for that!

Thus, with the pre-merge CI in place, both projects hope to avoid
unintentional changes to Rust that break the kernel. This means that,
in general, apart from intentional changes on their side (that we will
need to workaround conditionally on our side), the upcoming Rust compiler
versions should generally work.

For instance, currently, the beta (1.80.0) and nightly (1.81.0) branches
work as well.

Similarly, we kept the minimum as it is for `bindgen`. `bindgen` is also
adding the kernel to its CI -- thanks!

Cheers,
Miguel


Miguel Ojeda (13):
  rust: macros: indent list item in `paste!`'s docs
  rust: init: simplify from `map_err` to `inspect_err`
  rust: allow `dead_code` for never constructed bindings
  rust: relax most deny-level lints to warnings
  rust: simplify Clippy warning flags set
  rust: start supporting several compiler versions
  rust: warn about `bindgen` versions 0.66.0 and 0.66.1
  rust: work around `bindgen` 0.69.0 issue
  rust: avoid assuming a particular `bindgen` build
  rust: start supporting several `bindgen` versions
  kbuild: rust: add `rustc-version` support
  rust: support the new `-Zub-checks` flag
  docs: rust: quick-start: add section on Linux distributions

 Documentation/process/changes.rst  |   9 +--
 Documentation/rust/quick-start.rst | 118 +++++++++++++++++++++++------
 Makefile                           |  29 +++----
 init/Kconfig                       |  11 ++-
 lib/Kconfig.debug                  |  18 +++++
 rust/Makefile                      |   4 +-
 rust/bindings/lib.rs               |   1 +
 rust/kernel/init.rs                |  12 +--
 rust/macros/lib.rs                 |   2 +-
 rust/uapi/lib.rs                   |   1 +
 scripts/Kconfig.include            |   6 ++
 scripts/Makefile.compiler          |   4 +
 scripts/rust_is_available.sh       |  20 ++---
 scripts/rust_is_available_test.py  |  40 +++++-----
 scripts/rustc-version.sh           |  52 +++++++++++++
 15 files changed, 238 insertions(+), 89 deletions(-)
 create mode 100755 scripts/rustc-version.sh


base-commit: f2661062f16b2de5d7b6a5c42a9a5c96326b8454
-- 
2.45.2

Re: [PATCH 00/13] Support several Rust toolchain versions

[Benno Lossin]

On 01.07.24 20:36, Miguel Ojeda wrote:
> Hi all,
> 
> It is time to start supporting several Rust toolchain versions and thus
> establish a minimum Rust compiler and `bindgen` version.
> 
> For the Rust compiler, we will start with a window of two stable
> releases, and widen it over time. This series keeps the minimum where
> it is (1.78.0), but adds support for the recently released 1.79.0.
> 
> This should already be enough for kernel developers in distributions that
> provide recent Rust compiler versions routinely, such as Arch Linux,
> Debian Unstable (outside the freeze period), Fedora Linux, Gentoo
> Linux (especially the testing channel), Nix (unstable) and openSUSE
> Tumbleweed. A documentation adds the instructions for each of them.
> 
> In addition, Rust for Linux is now being built-tested in Rust's
> pre-merge CI. That is, every change that is attempting to land into the
> Rust compiler is tested against the kernel, and it is merged only if it
> passes -- thanks to the Rust project for that!
> 
> Thus, with the pre-merge CI in place, both projects hope to avoid
> unintentional changes to Rust that break the kernel. This means that,
> in general, apart from intentional changes on their side (that we will
> need to workaround conditionally on our side), the upcoming Rust compiler
> versions should generally work.
> 
> For instance, currently, the beta (1.80.0) and nightly (1.81.0) branches
> work as well.
> 
> Similarly, we kept the minimum as it is for `bindgen`. `bindgen` is also
> adding the kernel to its CI -- thanks!
> 
> Cheers,
> Miguel
> 
> 
> Miguel Ojeda (13):
>   rust: macros: indent list item in `paste!`'s docs
>   rust: init: simplify from `map_err` to `inspect_err`
>   rust: allow `dead_code` for never constructed bindings
>   rust: relax most deny-level lints to warnings
>   rust: simplify Clippy warning flags set
>   rust: start supporting several compiler versions
>   rust: warn about `bindgen` versions 0.66.0 and 0.66.1
>   rust: work around `bindgen` 0.69.0 issue
>   rust: avoid assuming a particular `bindgen` build
>   rust: start supporting several `bindgen` versions
>   kbuild: rust: add `rustc-version` support
>   rust: support the new `-Zub-checks` flag
>   docs: rust: quick-start: add section on Linux distributions
> 
>  Documentation/process/changes.rst  |   9 +--
>  Documentation/rust/quick-start.rst | 118 +++++++++++++++++++++++------
>  Makefile                           |  29 +++----
>  init/Kconfig                       |  11 ++-
>  lib/Kconfig.debug                  |  18 +++++
>  rust/Makefile                      |   4 +-
>  rust/bindings/lib.rs               |   1 +
>  rust/kernel/init.rs                |  12 +--
>  rust/macros/lib.rs                 |   2 +-
>  rust/uapi/lib.rs                   |   1 +
>  scripts/Kconfig.include            |   6 ++
>  scripts/Makefile.compiler          |   4 +
>  scripts/rust_is_available.sh       |  20 ++---
>  scripts/rust_is_available_test.py  |  40 +++++-----
>  scripts/rustc-version.sh           |  52 +++++++++++++
>  15 files changed, 238 insertions(+), 89 deletions(-)
>  create mode 100755 scripts/rustc-version.sh
> 
> 
> base-commit: f2661062f16b2de5d7b6a5c42a9a5c96326b8454
> --
> 2.45.2

I applied the series and successfully ran the kunit tests on nixos.
I tried the following rust versions via fenix:
- rustc 1.78.0 (9b00956e5 2024-04-29)
- rustc 1.79.0 (129f3b996 2024-06-10)
- 1.80.0-beta.4 (64a1fe671 2024-06-21)
- 1.81.0-nightly (6868c831a 2024-06-30)

My bindgen version is 0.69.4.

Everything worked as expected :)

Tested-by: Benno Lossin <benno.lossin@proton.me>

---
Cheers,
Benno

Re: [PATCH 00/13] Support several Rust toolchain versions

[Miguel Ojeda]

On Tue, Jul 2, 2024 at 8:25 AM Benno Lossin <benno.lossin@proton.me> wrote:
>
> I applied the series and successfully ran the kunit tests on nixos.
> I tried the following rust versions via fenix:
> - rustc 1.78.0 (9b00956e5 2024-04-29)
> - rustc 1.79.0 (129f3b996 2024-06-10)
> - 1.80.0-beta.4 (64a1fe671 2024-06-21)
> - 1.81.0-nightly (6868c831a 2024-06-30)
>
> My bindgen version is 0.69.4.
>
> Everything worked as expected :)

Thanks Benno! I tried nixpkgs' toolchain for the examples in the docs
patch, but not fenix's ones, so it's good to know those work as well. :)

Cheers,
Miguel

Re: [PATCH 00/13] Support several Rust toolchain versions

[Andreas Hindborg]

Hi Miguel,

Miguel Ojeda <ojeda@kernel.org> writes:

> Hi all,
>
> It is time to start supporting several Rust toolchain versions and thus
> establish a minimum Rust compiler and `bindgen` version.
>
> For the Rust compiler, we will start with a window of two stable
> releases, and widen it over time. This series keeps the minimum where
> it is (1.78.0), but adds support for the recently released 1.79.0.
>
> This should already be enough for kernel developers in distributions that
> provide recent Rust compiler versions routinely, such as Arch Linux,
> Debian Unstable (outside the freeze period), Fedora Linux, Gentoo
> Linux (especially the testing channel), Nix (unstable) and openSUSE
> Tumbleweed. A documentation adds the instructions for each of them.
>
> In addition, Rust for Linux is now being built-tested in Rust's
> pre-merge CI. That is, every change that is attempting to land into the
> Rust compiler is tested against the kernel, and it is merged only if it
> passes -- thanks to the Rust project for that!
>
> Thus, with the pre-merge CI in place, both projects hope to avoid
> unintentional changes to Rust that break the kernel. This means that,
> in general, apart from intentional changes on their side (that we will
> need to workaround conditionally on our side), the upcoming Rust compiler
> versions should generally work.
>
> For instance, currently, the beta (1.80.0) and nightly (1.81.0) branches
> work as well.
>
> Similarly, we kept the minimum as it is for `bindgen`. `bindgen` is also
> adding the kernel to its CI -- thanks!
>
> Cheers,
> Miguel
>

Applied the series to [1], based on v6.9:

rustup override set --path ../rnull-v6.9-build 1.76.0
make O=../rnull-v6.9-build LLVM=1

Builds fine.

rustup override set --path ../rnull-v6.9-build 1.79.0
make O=../rnull-v6.9-build LLVM=1

make[1]: Entering directory '/home/aeh/src/linux-rust/rnull-v6.9-build'
  GEN     Makefile
mkdir -p /home/aeh/src/linux-rust/rnull-v6.9-build/tools/objtool && make O=/home/aeh/src/linux-rust/rnull-v6.9-build subdir=tools/objtool --no-print-directory -C objtool
  CALL    /home/aeh/src/linux-rust/rnull-v6.9/scripts/checksyscalls.sh
  INSTALL libsubcmd_headers
  RUSTC L rust/core.o
error: data-layout for target `target-12379853866016577623`, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128`, differs from LLVM target's `x86_64-linux-gnu` default layout, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128`

error: aborting due to 1 previous error

make[3]: *** [/home/aeh/src/linux-rust/rnull-v6.9/rust/Makefile:461: rust/core.o] Error 1
make[2]: *** [/home/aeh/src/linux-rust/rnull-v6.9/Makefile:1206: prepare] Error 2
make[1]: *** [/home/aeh/src/linux-rust/rnull-v6.9/Makefile:240: __sub-make] Error 2
make[1]: Leaving directory '/home/aeh/src/linux-rust/rnull-v6.9-build'
make: *** [Makefile:240: __sub-make] Error 2
error: Recipe `lo` failed with exit code 2


rm ../rnull-v6.9-build/rust
make O=../rnull-v6.9-build LLVM=1

same result.

rm ../rnull-v6.9-build/rust
<configure>
make O=../rnull-v6.9-build LLVM=1

same result.

Maybe because I am on v6.9?


Best regards,
Andreas


[1] https://github.com/metaspace/linux/tree/rnull-v6.9

Re: [PATCH 00/13] Support several Rust toolchain versions

[Miguel Ojeda]

On Wed, Jul 3, 2024 at 7:35 PM Andreas Hindborg <nmi@metaspace.dk> wrote:
>
> Maybe because I am on v6.9?

Yeah, you need https://lore.kernel.org/rust-for-linux/20240401212303.537355-4-ojeda@kernel.org/
-- please see the "## LLVM's data layout" section in the commit
message.

Thanks for giving it a try!

Cheers,
Miguel

Re: [PATCH 00/13] Support several Rust toolchain versions

[Andreas Hindborg]

"Miguel Ojeda" <miguel.ojeda.sandonis@gmail.com> writes:

> On Wed, Jul 3, 2024 at 7:35 PM Andreas Hindborg <nmi@metaspace.dk> wrote:
>>
>> Maybe because I am on v6.9?
>
> Yeah, you need https://lore.kernel.org/rust-for-linux/20240401212303.537355-4-ojeda@kernel.org/
> -- please see the "## LLVM's data layout" section in the commit
> message.

I applied it to the rnull tree based on v6.10-rc3 [1] and ran some tests
with rustc 1.78.0 and 1.79.0 without encountering any problems.


Tested-by: Andreas Hindborg <a.hindborg@samsung.com>


Best regards,
Andreas


[1] https://github.com/metaspace/linux/tree/rnull-v6.10-rc3