linux/samples/rust
Linus Torvalds 784faa8eca Rust changes for v6.19
Toolchain and infrastructure:
 
  - Add support for 'syn'.
 
      Syn is a parsing library for parsing a stream of Rust tokens into a
      syntax tree of Rust source code.
 
      Currently this library is geared toward use in Rust procedural
      macros, but contains some APIs that may be useful more generally.
 
    'syn' allows us to greatly simplify writing complex macros such as
    'pin-init' (Benno has already prepared the 'syn'-based version). We
    will use it in the 'macros' crate too.
 
    'syn' is the most downloaded Rust crate (according to crates.io), and
    it is also used by the Rust compiler itself. While the amount of code
    is substantial, there should not be many updates needed for these
    crates, and even if there are, they should not be too big, e.g. +7k
    -3k lines across the 3 crates in the last year.
 
    'syn' requires two smaller dependencies: 'quote' and 'proc-macro2'.
    I only modified their code to remove a third dependency
    ('unicode-ident') and to add the SPDX identifiers. The code can be
    easily verified to exactly match upstream with the provided scripts.
 
    They are all licensed under "Apache-2.0 OR MIT", like the other
    vendored 'alloc' crate we had for a while.
 
    Please see the merge commit with the cover letter for more context.
 
  - Allow 'unreachable_pub' and 'clippy::disallowed_names' for doctests.
 
    Examples (i.e. doctests) may want to do things like show public items
    and use names such as 'foo'.
 
    Nevertheless, we still try to keep examples as close to real code as
    possible (this is part of why running Clippy on doctests is important
    for us, e.g. for safety comments, which userspace Rust does not
    support yet but we are stricter).
 
 'kernel' crate:
 
  - Replace our custom 'CStr' type with 'core::ffi::CStr'.
 
    Using the standard library type reduces our custom code footprint,
    and we retain needed custom functionality through an extension trait
    and a new 'fmt!' macro which replaces the previous 'core' import.
 
    This started in 6.17 and continued in 6.18, and we finally land the
    replacement now. This required quite some stamina from Tamir, who
    split the changes in steps to prepare for the flag day change here.
 
  - Replace 'kernel::c_str!' with C string literals.
 
    C string literals were added in Rust 1.77, which produce '&CStr's
    (the 'core' one), so now we can write:
 
        c"hi"
 
    instead of:
 
        c_str!("hi")
 
  - Add 'num' module for numerical features.
 
    It includes the 'Integer' trait, implemented for all primitive
    integer types.
 
    It also includes the 'Bounded' integer wrapping type: an integer
    value that requires only the 'N' less significant bits of the wrapped
    type to be encoded:
 
        // An unsigned 8-bit integer, of which only the 4 LSBs are used.
        let v = Bounded::<u8, 4>:🆕:<15>();
        assert_eq!(v.get(), 15);
 
    'Bounded' is useful to e.g. enforce guarantees when working with
    bitfields that have an arbitrary number of bits.
 
    Values can be constructed from simple non-constant expressions or,
    for more complex ones, validated at runtime.
 
    'Bounded' also comes with comparison and arithmetic operations (with
    both their backing type and other 'Bounded's with a compatible
    backing type), casts to change the backing type, extending/shrinking
    and infallible/fallible conversions from/to primitives as applicable.
 
  - 'rbtree' module: add immutable cursor ('Cursor').
 
    It enables to use just an immutable tree reference where appropriate.
    The existing fully-featured mutable cursor is renamed to 'CursorMut'.
 
 kallsyms:
 
  - Fix wrong "big" kernel symbol type read from procfs.
 
 'pin-init' crate:
 
  - A couple minor fixes (Benno asked me to pick these patches up for
    him this cycle).
 
 Documentation:
 
  - Quick Start guide: add Debian 13 (Trixie).
 
    Debian Stable is now able to build Linux, since Debian 13 (released
    2025-08-09) packages Rust 1.85.0, which is recent enough.
 
    We are planning to propose that the minimum supported Rust version in
    Linux follows Debian Stable releases, with Debian 13 being the first
    one we upgrade to, i.e. Rust 1.85.
 
 MAINTAINERS:
 
  - Add entry for the new 'num' module.
 
  - Remove Alex as Rust maintainer: he hasn't had the time to contribute
    for a few years now, so it is a no-op change in practice.
 
 And a few other cleanups and improvements.
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Merge tag 'rust-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Add support for 'syn'.

     Syn is a parsing library for parsing a stream of Rust tokens into a
     syntax tree of Rust source code.

     Currently this library is geared toward use in Rust procedural
     macros, but contains some APIs that may be useful more generally.

     'syn' allows us to greatly simplify writing complex macros such as
     'pin-init' (Benno has already prepared the 'syn'-based version). We
     will use it in the 'macros' crate too.

     'syn' is the most downloaded Rust crate (according to crates.io),
     and it is also used by the Rust compiler itself. While the amount
     of code is substantial, there should not be many updates needed for
     these crates, and even if there are, they should not be too big,
     e.g. +7k -3k lines across the 3 crates in the last year.

     'syn' requires two smaller dependencies: 'quote' and 'proc-macro2'.
     I only modified their code to remove a third dependency
     ('unicode-ident') and to add the SPDX identifiers. The code can be
     easily verified to exactly match upstream with the provided
     scripts.

     They are all licensed under "Apache-2.0 OR MIT", like the other
     vendored 'alloc' crate we had for a while.

     Please see the merge commit with the cover letter for more context.

   - Allow 'unreachable_pub' and 'clippy::disallowed_names' for
     doctests.

     Examples (i.e. doctests) may want to do things like show public
     items and use names such as 'foo'.

     Nevertheless, we still try to keep examples as close to real code
     as possible (this is part of why running Clippy on doctests is
     important for us, e.g. for safety comments, which userspace Rust
     does not support yet but we are stricter).

  'kernel' crate:

   - Replace our custom 'CStr' type with 'core::ffi::CStr'.

     Using the standard library type reduces our custom code footprint,
     and we retain needed custom functionality through an extension
     trait and a new 'fmt!' macro which replaces the previous 'core'
     import.

     This started in 6.17 and continued in 6.18, and we finally land the
     replacement now. This required quite some stamina from Tamir, who
     split the changes in steps to prepare for the flag day change here.

   - Replace 'kernel::c_str!' with C string literals.

     C string literals were added in Rust 1.77, which produce '&CStr's
     (the 'core' one), so now we can write:

         c"hi"

     instead of:

         c_str!("hi")

   - Add 'num' module for numerical features.

     It includes the 'Integer' trait, implemented for all primitive
     integer types.

     It also includes the 'Bounded' integer wrapping type: an integer
     value that requires only the 'N' least significant bits of the
     wrapped type to be encoded:

         // An unsigned 8-bit integer, of which only the 4 LSBs are used.
         let v = Bounded::<u8, 4>:🆕:<15>();
         assert_eq!(v.get(), 15);

     'Bounded' is useful to e.g. enforce guarantees when working with
     bitfields that have an arbitrary number of bits.

     Values can also be constructed from simple non-constant expressions
     or, for more complex ones, validated at runtime.

     'Bounded' also comes with comparison and arithmetic operations
     (with both their backing type and other 'Bounded's with a
     compatible backing type), casts to change the backing type,
     extending/shrinking and infallible/fallible conversions from/to
     primitives as applicable.

   - 'rbtree' module: add immutable cursor ('Cursor').

     It enables to use just an immutable tree reference where
     appropriate. The existing fully-featured mutable cursor is renamed
     to 'CursorMut'.

  kallsyms:

   - Fix wrong "big" kernel symbol type read from procfs.

  'pin-init' crate:

   - A couple minor fixes (Benno asked me to pick these patches up for
     him this cycle).

  Documentation:

   - Quick Start guide: add Debian 13 (Trixie).

     Debian Stable is now able to build Linux, since Debian 13 (released
     2025-08-09) packages Rust 1.85.0, which is recent enough.

     We are planning to propose that the minimum supported Rust version
     in Linux follows Debian Stable releases, with Debian 13 being the
     first one we upgrade to, i.e. Rust 1.85.

  MAINTAINERS:

   - Add entry for the new 'num' module.

   - Remove Alex as Rust maintainer: he hasn't had the time to
     contribute for a few years now, so it is a no-op change in
     practice.

  And a few other cleanups and improvements"

* tag 'rust-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (53 commits)
  rust: macros: support `proc-macro2`, `quote` and `syn`
  rust: syn: enable support in kbuild
  rust: syn: add `README.md`
  rust: syn: remove `unicode-ident` dependency
  rust: syn: add SPDX License Identifiers
  rust: syn: import crate
  rust: quote: enable support in kbuild
  rust: quote: add `README.md`
  rust: quote: add SPDX License Identifiers
  rust: quote: import crate
  rust: proc-macro2: enable support in kbuild
  rust: proc-macro2: add `README.md`
  rust: proc-macro2: remove `unicode_ident` dependency
  rust: proc-macro2: add SPDX License Identifiers
  rust: proc-macro2: import crate
  rust: kbuild: support using libraries in `rustc_procmacro`
  rust: kbuild: support skipping flags in `rustc_test_library`
  rust: kbuild: add proc macro library support
  rust: kbuild: simplify `--cfg` handling
  rust: kbuild: introduce `core-flags` and `core-skip_flags`
  ...
2025-12-03 14:16:49 -08:00
..
hostprogs
Kconfig Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
Makefile Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
rust_configfs.rs for-6.18/block-20250929 2025-10-02 10:16:56 -07:00
rust_debugfs.rs rust: debugfs: Replace the usage of Rust native atomics 2025-11-12 08:56:42 -08:00
rust_debugfs_scoped.rs Rust changes for v6.19 2025-12-03 14:16:49 -08:00
rust_dma.rs drm next for 6.18-rc1 2025-10-02 12:47:25 -07:00
rust_driver_auxiliary.rs rust: pci: use pci::Vendor instead of bindings::PCI_VENDOR_ID_* 2025-09-01 20:16:36 +02:00
rust_driver_faux.rs Driver core updates for 6.15-rc1 2025-04-01 11:02:03 -07:00
rust_driver_pci.rs drm next for 6.18-rc1 2025-10-02 12:47:25 -07:00
rust_driver_platform.rs samples: rust: platform: remove trailing commas 2025-10-20 04:04:23 +02:00
rust_driver_usb.rs samples: rust: add a USB driver sample 2025-09-24 13:13:04 +02:00
rust_minimal.rs rust: module: introduce `authors` key 2025-03-10 15:12:17 +01:00
rust_misc_device.rs Merge patch series "Rust support for `struct iov_iter`" 2025-09-06 13:27:23 +02:00
rust_print_events.c rust: samples: add tracepoint to Rust sample 2024-11-04 16:21:44 -05:00
rust_print_main.rs rust: use `kernel::{fmt,prelude::fmt!}` 2025-07-21 01:16:35 +02:00