linux/drivers/android
Linus Torvalds 26ff969926 Rust changes for v7.1
Toolchain and infrastructure:
 
  - Bump the minimum Rust version to 1.85.0 (and 'bindgen' to 0.71.1).
 
    As proposed in LPC 2025 and the Maintainers Summit [1], we are going
    to follow Debian Stable's Rust versions as our minimum versions.
 
    Debian Trixie was released on 2025-08-09 with a Rust 1.85.0 and
    'bindgen' 0.71.1 toolchain, which is a fair amount of time for e.g.
    kernel developers to upgrade.
 
    Other major distributions support a Rust version that is high enough
    as well, including:
 
      + Arch Linux.
      + Fedora Linux.
      + Gentoo Linux.
      + Nix.
      + openSUSE Slowroll and openSUSE Tumbleweed.
      + Ubuntu 25.10 and 26.04 LTS. In addition, 24.04 LTS using
        their versioned packages.
 
    The merged patch series comes with the associated cleanups and
    simplifications treewide that can be performed thanks to both bumps,
    as well as documentation updates.
 
    In addition, start using 'bindgen''s '--with-attribute-custom-enum'
    feature to set the 'cfi_encoding' attribute for the 'lru_status' enum
    used in Binder.
 
    Link: https://lwn.net/Articles/1050174/ [1]
 
  - Add experimental Kconfig option ('CONFIG_RUST_INLINE_HELPERS') that
    inlines C helpers into Rust.
 
    Essentially, it performs a step similar to LTO, but just for the
    helpers, i.e. very local and fast.
 
    It relies on 'llvm-link' and its '--internalize' flag, and requires
    a compatible LLVM between Clang and 'rustc' (i.e. same major version,
    'CONFIG_RUSTC_CLANG_LLVM_COMPATIBLE'). It is only enabled for two
    architectures for now.
 
    The result is a measurable speedup in different workloads that
    different users have tested. For instance, for the null block driver,
    it amounts to a 2%.
 
  - Support global per-version flags.
 
    While we already have per-version flags in many places, we didn't
    have a place to set global ones that depend on the compiler version,
    i.e. in 'rust_common_flags', which sometimes is needed to e.g. tweak
    the lints set per version.
 
    Use that to allow the 'clippy::precedence' lint for Rust < 1.86.0,
    since it had a change in behavior.
 
  - Support overriding the crate name and apply it to Rust Binder, which
    wanted the module to be called 'rust_binder'.
 
  - Add the remaining '__rust_helper' annotations (started in the
    previous cycle).
 
 'kernel' crate:
 
  - Introduce the 'const_assert!' macro: a more powerful version of
    'static_assert!' that can refer to generics inside functions or
    implementation bodies, e.g.:
 
        fn f<const N: usize>() {
            const_assert!(N > 1);
        }
 
        fn g<T>() {
            const_assert!(size_of::<T>() > 0, "T cannot be ZST");
        }
 
    In addition, reorganize our set of build-time assertion macros
    ('{build,const,static_assert}!') to live in the 'build_assert'
    module.
 
    Finally, improve the docs as well to clarify how these are different
    from one another and how to pick the right one to use, and their
    equivalence (if any) to the existing C ones for extra clarity.
 
  - 'sizes' module: add 'SizeConstants' trait.
 
    This gives us typed 'SZ_*' constants (avoiding casts) for use in
    device address spaces where the address width depends on the hardware
    (e.g. 32-bit MMIO windows, 64-bit GPU framebuffers, etc.), e.g.:
 
        let gpu_heap = 14 * u64::SZ_1M;
        let mmio_window = u32::SZ_16M;
 
  - 'clk' module: implement 'Send' and 'Sync' for 'Clk' and thus simplify
    the users in Tyr and PWM.
 
  - 'ptr' module: add 'const_align_up'.
 
  - 'str' module: improve the documentation of the 'c_str!' macro to
    explain that one should only use it for non-literal cases (for the
    other case we instead use C string literals, e.g. 'c"abc"').
 
  - Disallow the use of 'CStr::{as_ptr,from_ptr}' and clean one such use
    in the 'task' module.
 
  - 'sync' module: finish the move of 'ARef' and 'AlwaysRefCounted'
    outside of the 'types' module, i.e. update the last remaining
    instances and finally remove the re-exports.
 
  - 'error' module: clarify that 'from_err_ptr' can return 'Ok(NULL)',
    including runtime-tested examples.
 
    The intention is to hopefully prevent UB that assumes the result of
    the function is not 'NULL' if successful. This originated from a case
    of UB I noticed in 'regulator' that created a 'NonNull' on it.
 
 Timekeeping:
 
  - Expand the example section in the 'HrTimer' documentation.
 
  - Mark the 'ClockSource' trait as unsafe to ensure valid values for
    'ktime_get()'.
 
  - Add 'Delta::from_nanos()'.
 
 'pin-init' crate:
 
  - Replace the 'Zeroable' impls for 'Option<NonZero*>' with impls of
    'ZeroableOption' for 'NonZero*'.
 
  - Improve feature gate handling for unstable features.
 
  - Declutter the documentation of implementations of 'Zeroable' for
    tuples.
 
  - Replace uses of 'addr_of[_mut]!' with '&raw [mut]'.
 
 rust-analyzer:
 
  - Add type annotations to 'generate_rust_analyzer.py'.
 
  - Add support for scripts written in Rust ('generate_rust_target.rs',
    'rustdoc_test_builder.rs', 'rustdoc_test_gen.rs').
 
  - Refactor 'generate_rust_analyzer.py' to explicitly identify host and
    target crates, improve readability, and reduce duplication.
 
 And some other fixes, cleanups and improvements.
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Merge tag 'rust-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

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

   - Bump the minimum Rust version to 1.85.0 (and 'bindgen' to 0.71.1).

     As proposed in LPC 2025 and the Maintainers Summit [1], we are
     going to follow Debian Stable's Rust versions as our minimum
     versions.

     Debian Trixie was released on 2025-08-09 with a Rust 1.85.0 and
     'bindgen' 0.71.1 toolchain, which is a fair amount of time for e.g.
     kernel developers to upgrade.

     Other major distributions support a Rust version that is high
     enough as well, including:

       + Arch Linux.
       + Fedora Linux.
       + Gentoo Linux.
       + Nix.
       + openSUSE Slowroll and openSUSE Tumbleweed.
       + Ubuntu 25.10 and 26.04 LTS. In addition, 24.04 LTS using
         their versioned packages.

     The merged patch series comes with the associated cleanups and
     simplifications treewide that can be performed thanks to both
     bumps, as well as documentation updates.

     In addition, start using 'bindgen''s '--with-attribute-custom-enum'
     feature to set the 'cfi_encoding' attribute for the 'lru_status'
     enum used in Binder.

     Link: https://lwn.net/Articles/1050174/ [1]

   - Add experimental Kconfig option ('CONFIG_RUST_INLINE_HELPERS') that
     inlines C helpers into Rust.

     Essentially, it performs a step similar to LTO, but just for the
     helpers, i.e. very local and fast.

     It relies on 'llvm-link' and its '--internalize' flag, and requires
     a compatible LLVM between Clang and 'rustc' (i.e. same major
     version, 'CONFIG_RUSTC_CLANG_LLVM_COMPATIBLE'). It is only enabled
     for two architectures for now.

     The result is a measurable speedup in different workloads that
     different users have tested. For instance, for the null block
     driver, it amounts to a 2%.

   - Support global per-version flags.

     While we already have per-version flags in many places, we didn't
     have a place to set global ones that depend on the compiler
     version, i.e. in 'rust_common_flags', which sometimes is needed to
     e.g. tweak the lints set per version.

     Use that to allow the 'clippy::precedence' lint for Rust < 1.86.0,
     since it had a change in behavior.

   - Support overriding the crate name and apply it to Rust Binder,
     which wanted the module to be called 'rust_binder'.

   - Add the remaining '__rust_helper' annotations (started in the
     previous cycle).

  'kernel' crate:

   - Introduce the 'const_assert!' macro: a more powerful version of
     'static_assert!' that can refer to generics inside functions or
     implementation bodies, e.g.:

         fn f<const N: usize>() {
             const_assert!(N > 1);
         }

         fn g<T>() {
             const_assert!(size_of::<T>() > 0, "T cannot be ZST");
         }

     In addition, reorganize our set of build-time assertion macros
     ('{build,const,static_assert}!') to live in the 'build_assert'
     module.

     Finally, improve the docs as well to clarify how these are
     different from one another and how to pick the right one to use,
     and their equivalence (if any) to the existing C ones for extra
     clarity.

   - 'sizes' module: add 'SizeConstants' trait.

     This gives us typed 'SZ_*' constants (avoiding casts) for use in
     device address spaces where the address width depends on the
     hardware (e.g. 32-bit MMIO windows, 64-bit GPU framebuffers, etc.),
     e.g.:

         let gpu_heap = 14 * u64::SZ_1M;
         let mmio_window = u32::SZ_16M;

   - 'clk' module: implement 'Send' and 'Sync' for 'Clk' and thus
     simplify the users in Tyr and PWM.

   - 'ptr' module: add 'const_align_up'.

   - 'str' module: improve the documentation of the 'c_str!' macro to
     explain that one should only use it for non-literal cases (for the
     other case we instead use C string literals, e.g. 'c"abc"').

   - Disallow the use of 'CStr::{as_ptr,from_ptr}' and clean one such
     use in the 'task' module.

   - 'sync' module: finish the move of 'ARef' and 'AlwaysRefCounted'
     outside of the 'types' module, i.e. update the last remaining
     instances and finally remove the re-exports.

   - 'error' module: clarify that 'from_err_ptr' can return 'Ok(NULL)',
     including runtime-tested examples.

     The intention is to hopefully prevent UB that assumes the result of
     the function is not 'NULL' if successful. This originated from a
     case of UB I noticed in 'regulator' that created a 'NonNull' on it.

  Timekeeping:

   - Expand the example section in the 'HrTimer' documentation.

   - Mark the 'ClockSource' trait as unsafe to ensure valid values for
     'ktime_get()'.

   - Add 'Delta::from_nanos()'.

  'pin-init' crate:

   - Replace the 'Zeroable' impls for 'Option<NonZero*>' with impls of
     'ZeroableOption' for 'NonZero*'.

   - Improve feature gate handling for unstable features.

   - Declutter the documentation of implementations of 'Zeroable' for
     tuples.

   - Replace uses of 'addr_of[_mut]!' with '&raw [mut]'.

  rust-analyzer:

   - Add type annotations to 'generate_rust_analyzer.py'.

   - Add support for scripts written in Rust ('generate_rust_target.rs',
     'rustdoc_test_builder.rs', 'rustdoc_test_gen.rs').

   - Refactor 'generate_rust_analyzer.py' to explicitly identify host
     and target crates, improve readability, and reduce duplication.

  And some other fixes, cleanups and improvements"

* tag 'rust-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (79 commits)
  rust: sizes: add SizeConstants trait for device address space constants
  rust: kernel: update `file_with_nul` comment
  rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0
  rust: kbuild: support global per-version flags
  rust: declare cfi_encoding for lru_status
  docs: rust: general-information: use real example
  docs: rust: general-information: simplify Kconfig example
  docs: rust: quick-start: remove GDB/Binutils mention
  docs: rust: quick-start: remove Nix "unstable channel" note
  docs: rust: quick-start: remove Gentoo "testing" note
  docs: rust: quick-start: add Ubuntu 26.04 LTS and remove subsection title
  docs: rust: quick-start: update minimum Ubuntu version
  docs: rust: quick-start: update Ubuntu versioned packages
  docs: rust: quick-start: openSUSE provides `rust-src` package nowadays
  rust: kbuild: remove "dummy parameter" workaround for `bindgen` < 0.71.1
  rust: kbuild: update `bindgen --rust-target` version and replace comment
  rust: rust_is_available: remove warning for `bindgen` < 0.69.5 && libclang >= 19.1
  rust: rust_is_available: remove warning for `bindgen` 0.66.[01]
  rust: bump `bindgen` minimum supported version to 0.71.1 (Debian Trixie)
  rust: block: update `const_refs_to_static` MSRV TODO comment
  ...
2026-04-13 09:54:20 -07:00
..
binder Rust changes for v7.1 2026-04-13 09:54:20 -07:00
tests binder: mark binder_alloc_exhaustive_test as slow 2025-11-26 13:24:19 +01:00
Kconfig rust_binder: add Rust Binder driver 2025-09-19 09:40:46 +02:00
Makefile rust_binder: add Rust Binder driver 2025-09-19 09:40:46 +02:00
binder.c Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
binder_alloc.c Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
binder_alloc.h binder: Convert binder_alloc selftests to KUnit 2025-07-16 14:11:59 +02:00
binder_internal.h binder: add t->is_async and t->is_reply 2025-08-19 12:53:01 +02:00
binder_netlink.c tools: ynl-gen: add regeneration comment 2025-11-25 19:20:42 -08:00
binder_netlink.h tools: ynl-gen: add regeneration comment 2025-11-25 19:20:42 -08:00
binder_trace.h binder: add tracepoint for netlink reports 2025-08-19 12:53:02 +02:00
binderfs.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
dbitmap.h binder: fix double-free in dbitmap 2025-09-18 17:20:00 +02:00