Commit Graph

35 Commits

Author SHA1 Message Date
Linus Torvalds
5701725692 Rust changes for v6.12
Toolchain and infrastructure:
 
  - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up objtool
    warnings), teach objtool about 'noreturn' Rust symbols and mimic
    '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we should be
    objtool-warning-free, so enable it to run for all Rust object files.
 
  - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support.
 
  - Support 'RUSTC_VERSION', including re-config and re-build on change.
 
  - Split helpers file into several files in a folder, to avoid conflicts
    in it. Eventually those files will be moved to the right places with
    the new build system. In addition, remove the need to manually export
    the symbols defined there, reusing existing machinery for that.
 
  - Relax restriction on configurations with Rust + GCC plugins to just
    the RANDSTRUCT plugin.
 
 'kernel' crate:
 
  - New 'list' module: doubly-linked linked list for use with reference
    counted values, which is heavily used by the upcoming Rust Binder.
    This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed
    unique for the given ID), 'AtomicTracker' (tracks whether a 'ListArc'
    exists using an atomic), 'ListLinks' (the prev/next pointers for an
    item in a linked list), 'List' (the linked list itself), 'Iter' (an
    iterator over a 'List'), 'Cursor' (a cursor into a 'List' that allows
    to remove elements), 'ListArcField' (a field exclusively owned by a
    'ListArc'), as well as support for heterogeneous lists.
 
  - New 'rbtree' module: red-black tree abstractions used by the upcoming
    Rust Binder. This includes 'RBTree' (the red-black tree itself),
    'RBTreeNode' (a node), 'RBTreeNodeReservation' (a memory reservation
    for a node), 'Iter' and 'IterMut' (immutable and mutable iterators),
    'Cursor' (bidirectional cursor that allows to remove elements), as
    well as an entry API similar to the Rust standard library one.
 
  - 'init' module: add 'write_[pin_]init' methods and the 'InPlaceWrite'
    trait. Add the 'assert_pinned!' macro.
 
  - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by
    introducing an associated type in the trait.
 
  - 'alloc' module: add 'drop_contents' method to 'BoxExt'.
 
  - 'types' module: implement the 'ForeignOwnable' trait for
    'Pin<Box<T>>' and improve the trait's documentation. In addition,
    add the 'into_raw' method to the 'ARef' type.
 
  - 'error' module: in preparation for the upcoming Rust support for
    32-bit architectures, like arm, locally allow Clippy lint for those.
 
 Documentation:
 
  - https://rust.docs.kernel.org has been announced, so link to it.
 
  - Enable rustdoc's "jump to definition" feature, making its output a
    bit closer to the experience in a cross-referencer.
 
  - Debian Testing now also provides recent Rust releases (outside of
    the freeze period), so add it to the list.
 
 MAINTAINERS:
 
  - Trevor is joining as reviewer of the "RUST" entry.
 
 And a few other small bits.
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Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux

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

   - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up
     objtool warnings), teach objtool about 'noreturn' Rust symbols and
     mimic '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we
     should be objtool-warning-free, so enable it to run for all Rust
     object files.

   - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support.

   - Support 'RUSTC_VERSION', including re-config and re-build on
     change.

   - Split helpers file into several files in a folder, to avoid
     conflicts in it. Eventually those files will be moved to the right
     places with the new build system. In addition, remove the need to
     manually export the symbols defined there, reusing existing
     machinery for that.

   - Relax restriction on configurations with Rust + GCC plugins to just
     the RANDSTRUCT plugin.

  'kernel' crate:

   - New 'list' module: doubly-linked linked list for use with reference
     counted values, which is heavily used by the upcoming Rust Binder.

     This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed
     unique for the given ID), 'AtomicTracker' (tracks whether a
     'ListArc' exists using an atomic), 'ListLinks' (the prev/next
     pointers for an item in a linked list), 'List' (the linked list
     itself), 'Iter' (an iterator over a 'List'), 'Cursor' (a cursor
     into a 'List' that allows to remove elements), 'ListArcField' (a
     field exclusively owned by a 'ListArc'), as well as support for
     heterogeneous lists.

   - New 'rbtree' module: red-black tree abstractions used by the
     upcoming Rust Binder.

     This includes 'RBTree' (the red-black tree itself), 'RBTreeNode' (a
     node), 'RBTreeNodeReservation' (a memory reservation for a node),
     'Iter' and 'IterMut' (immutable and mutable iterators), 'Cursor'
     (bidirectional cursor that allows to remove elements), as well as
     an entry API similar to the Rust standard library one.

   - 'init' module: add 'write_[pin_]init' methods and the
     'InPlaceWrite' trait. Add the 'assert_pinned!' macro.

   - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by
     introducing an associated type in the trait.

   - 'alloc' module: add 'drop_contents' method to 'BoxExt'.

   - 'types' module: implement the 'ForeignOwnable' trait for
     'Pin<Box<T>>' and improve the trait's documentation. In addition,
     add the 'into_raw' method to the 'ARef' type.

   - 'error' module: in preparation for the upcoming Rust support for
     32-bit architectures, like arm, locally allow Clippy lint for
     those.

  Documentation:

   - https://rust.docs.kernel.org has been announced, so link to it.

   - Enable rustdoc's "jump to definition" feature, making its output a
     bit closer to the experience in a cross-referencer.

   - Debian Testing now also provides recent Rust releases (outside of
     the freeze period), so add it to the list.

  MAINTAINERS:

   - Trevor is joining as reviewer of the "RUST" entry.

  And a few other small bits"

* tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux: (54 commits)
  kasan: rust: Add KASAN smoke test via UAF
  kbuild: rust: Enable KASAN support
  rust: kasan: Rust does not support KHWASAN
  kbuild: rust: Define probing macros for rustc
  kasan: simplify and clarify Makefile
  rust: cfi: add support for CFI_CLANG with Rust
  cfi: add CONFIG_CFI_ICALL_NORMALIZE_INTEGERS
  rust: support for shadow call stack sanitizer
  docs: rust: include other expressions in conditional compilation section
  kbuild: rust: replace proc macros dependency on `core.o` with the version text
  kbuild: rust: rebuild if the version text changes
  kbuild: rust: re-run Kconfig if the version text changes
  kbuild: rust: add `CONFIG_RUSTC_VERSION`
  rust: avoid `box_uninit_write` feature
  MAINTAINERS: add Trevor Gross as Rust reviewer
  rust: rbtree: add `RBTree::entry`
  rust: rbtree: add cursor
  rust: rbtree: add mutable iterator
  rust: rbtree: add iterator
  rust: rbtree: add red-black tree implementation backed by the C version
  ...
2024-09-25 10:25:40 -07:00
Miguel Ojeda
aeb0e24abb kbuild: rust: replace proc macros dependency on core.o with the version text
With the `RUSTC_VERSION_TEXT` rebuild support in place, now proc macros
can depend on that instead of `core.o`.

This means that both the `core` and `macros` crates can be built in
parallel, and that touching `core.o` does not trigger a rebuild of the
proc macros.

This could be accomplished using the same approach as for `core`
(i.e. depending directly on `include/config/RUSTC_VERSION_TEXT`). However,
that is considered an implementation detail [1], and thus it is best
to avoid it. Instead, let fixdep find a string that we explicitly
write down in the source code for this purpose (like it is done for
`include/linux/compiler-version.h`), which we can easily do (unlike for
`core`) since this is our own source code.

Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/rust-for-linux/CAK7LNAQBG0nDupXSgAAk-6nOqeqGVkr3H1RjYaqRJ1OxmLm6xA@mail.gmail.com/ [1]
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240902165535.1101978-5-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-05 22:44:51 +02:00
Boqun Feng
a5a3c952e8 rust: macros: provide correct provenance when constructing THIS_MODULE
Currently while defining `THIS_MODULE` symbol in `module!()`, the
pointer used to construct `ThisModule` is derived from an immutable
reference of `__this_module`, which means the pointer doesn't have
the provenance for writing, and that means any write to that pointer
is UB regardless of data races or not. However, the usage of
`THIS_MODULE` includes passing this pointer to functions that may write
to it (probably in unsafe code), and this will create soundness issues.

One way to fix this is using `addr_of_mut!()` but that requires the
unstable feature "const_mut_refs". So instead of `addr_of_mut()!`,
an extern static `Opaque` is used here: since `Opaque<T>` is transparent
to `T`, an extern static `Opaque` will just wrap the C symbol (defined
in a C compile unit) in an `Opaque`, which provides a pointer with
writable provenance via `Opaque::get()`. This fix the potential UBs
because of pointer provenance unmatched.

Reported-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Closes: https://rust-for-linux.zulipchat.com/#narrow/stream/x/topic/x/near/465412664
Fixes: 1fbde52bde ("rust: add `macros` crate")
Cc: stable@vger.kernel.org # 6.6.x: be2ca1e039: ("rust: types: Make Opaque::get const")
Link: https://lore.kernel.org/r/20240828180129.4046355-1-boqun.feng@gmail.com
[ Fixed two typos, reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-02 09:14:28 +02:00
Miguel Ojeda
289088d546 rust: module: add static pointer to {init,cleanup}_module()
Add the equivalent of the `___ADDRESSABLE()` annotation in the
`module_{init,exit}` macros to the Rust `module!` macro.

Without this, `objtool` would complain if enabled for Rust (under IBT
builds), e.g.:

    samples/rust/rust_print.o: warning: objtool: cleanup_module(): not an indirect call target
    samples/rust/rust_print.o: warning: objtool: init_module(): not an indirect call target

Tested-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240725183325.122827-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-18 23:34:37 +02:00
Miguel Ojeda
0ba521d694 rust: macros: indent list item in module!'s docs
Like commit e516211f61 ("rust: macros: indent list item in `paste!`'s
docs"), but for `module!`.

Reviewed-by: Trevor Gross <tmgross@umich.edu>
Link: https://lore.kernel.org/r/20240725184644.135185-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-29 14:23:54 +02:00
Miguel Ojeda
e516211f61 rust: macros: indent list item in paste!'s docs
A new style lint, `doc_lazy_continuation` [1], has been introduced in the
upcoming Rust 1.80 (currently in beta), which detects missing indentation
in code documentation.

We have one such case:

    error: doc list item missing indentation
    --> rust/macros/lib.rs:315:5
        |
    315 | /// default the span of the `[< >]` group is used.
        |     ^
        |
        = help: if this is supposed to be its own paragraph, add a blank line
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_lazy_continuation
        = note: `-D clippy::doc-lazy-continuation` implied by `-D clippy::style`
        = help: to override `-D clippy::style` add `#[allow(clippy::doc_lazy_continuation)]`
    help: indent this line
        |
    315 | ///   default the span of the `[< >]` group is used.
        |     ++

While the rendering of the docs by `rustdoc` is not affected, we apply
this kind of indentation elsewhere since it looks better.

Thus clean it up.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#/doc_lazy_continuation [1]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Finn Behrens <me@kloenk.dev>
Tested-by: Benno Lossin <benno.lossin@proton.me>
Tested-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20240709160615.998336-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-10 10:28:51 +02:00
FUJITA Tomonori
549d3c2ffb rust: add 'firmware' field support to module! macro
This adds 'firmware' field support to module! macro, corresponds to
MODULE_FIRMWARE macro. You can specify the file names of binary
firmware that the kernel module requires. The information is embedded
in the modinfo section of the kernel module. For example, a tool to
build an initramfs uses this information to put the firmware files
into the initramfs image.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240501123548.51769-1-fujita.tomonori@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-08 22:20:09 +02:00
Aswin Unnikrishnan
63249a070e rust: fix datatype in docs for module macro arguments
Remove the mention of byte array as datatype for `module` macro arguments
since the arguments are defined as string, and `alias` is a string array.

Signed-off-by: Aswin Unnikrishnan <aswinunni01@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240512112324.8514-2-aswinunni01@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-08 22:20:08 +02:00
Aswin Unnikrishnan
67f9c312b0 rust: add example for alias argument in module macro documentation
Add example for `alias` argument supported by `module` macro.
`alias` accepts an array of alternate names for the module as string.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Aswin Unnikrishnan <aswinunni01@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240512112324.8514-1-aswinunni01@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-07-08 22:20:08 +02:00
Linus Torvalds
8f5b5f7811 Rust changes for v6.10
The most notable change is the drop of the 'alloc' in-tree fork. This
 is nicely reflected in the diffstat as a ~10k lines drop. In turn, this
 makes the version upgrades way simpler and smaller in the future, e.g.
 the latest one in commit 56f64b3706 ("rust: upgrade to Rust 1.78.0").
 
 More importantly, this increases the chances that a newer compiler
 version just works, which in turn means supporting several compiler
 versions is easier now. Thus we will look into finally setting a minimum
 version in the near future.
 
 Toolchain and infrastructure:
 
  - Upgrade to Rust 1.78.0.
 
    This time around, due to how the kernel and Rust schedules have
    aligned, there are two upgrades in fact. These allow us to remove one
    more unstable feature ('offset_of') from the list, among other
    improvements.
 
  - Drop 'alloc' in-tree fork of the standard library crate, which means
    all the unstable features used by 'alloc' (~30 language ones, ~60
    library ones) are not a concern anymore.
 
  - Support DWARFv5 via the '-Zdwarf-version' flag.
 
  - Support zlib and zstd debuginfo compression via the
    '-Zdebuginfo-compression' flag.
 
 'kernel' crate:
 
  - Support allocation flags ('GFP_*'), particularly in 'Box' (via
    'BoxExt'), 'Vec' (via 'VecExt'), 'Arc' and 'UniqueArc', as well as in
    the 'init' module APIs.
 
  - Remove usage of the 'allocator_api' unstable feature.
 
  - Remove 'try_' prefix in allocation APIs' names.
 
  - Add 'VecExt' (an extension trait) to be able to drop the 'alloc'
    fork.
 
  - Add the '{make,to}_{upper,lower}case()' methods to 'CStr'/'CString'.
 
  - Add the 'as_ptr' method to 'ThisModule'.
 
  - Add the 'from_raw' method to 'ArcBorrow'.
 
  - Add the 'into_unique_or_drop' method to 'Arc'.
 
  - Display column number in the 'dbg!' macro output by applying the
    equivalent change done to the standard library one.
 
  - Migrate 'Work' to '#[pin_data]' thanks to the changes in the 'macros'
    crate, which allows to remove an unsafe call in its 'new' associated
    function.
 
  - Prevent namespacing issues when using the '[try_][pin_]init!' macros
    by changing the generated name of guard variables.
 
  - Make the 'get' method in 'Opaque' const.
 
  - Implement the 'Default' trait for 'LockClassKey'.
 
  - Remove unneeded 'kernel::prelude' imports from doctests.
 
  - Remove redundant imports.
 
 'macros' crate:
 
  - Add 'decl_generics' to 'parse_generics()' to support default values,
    and use that to allow them in '#[pin_data]'.
 
 Helpers:
 
  - Trivial English grammar fix.
 
 Documentation:
 
  - Add section on Rust Kselftests to the "Testing" document.
 
  - Expand the "Abstractions vs. bindings" section of the "General
    Information" document.
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Merge tag 'rust-6.10' of https://github.com/Rust-for-Linux/linux

Pull Rust updates from Miguel Ojeda:
 "The most notable change is the drop of the 'alloc' in-tree fork. This
  is nicely reflected in the diffstat as a ~10k lines drop. In turn,
  this makes the version upgrades way simpler and smaller in the future,
  e.g. the latest one in commit 56f64b3706 ("rust: upgrade to Rust
  1.78.0").

  More importantly, this increases the chances that a newer compiler
  version just works, which in turn means supporting several compiler
  versions is easier now. Thus we will look into finally setting a
  minimum version in the near future.

  Toolchain and infrastructure:

   - Upgrade to Rust 1.78.0

     This time around, due to how the kernel and Rust schedules have
     aligned, there are two upgrades in fact. These allow us to remove
     one more unstable feature ('offset_of') from the list, among other
     improvements

   - Drop 'alloc' in-tree fork of the standard library crate, which
     means all the unstable features used by 'alloc' (~30 language ones,
     ~60 library ones) are not a concern anymore

   - Support DWARFv5 via the '-Zdwarf-version' flag

   - Support zlib and zstd debuginfo compression via the
     '-Zdebuginfo-compression' flag

  'kernel' crate:

   - Support allocation flags ('GFP_*'), particularly in 'Box' (via
     'BoxExt'), 'Vec' (via 'VecExt'), 'Arc' and 'UniqueArc', as well as
     in the 'init' module APIs

   - Remove usage of the 'allocator_api' unstable feature

   - Remove 'try_' prefix in allocation APIs' names

   - Add 'VecExt' (an extension trait) to be able to drop the 'alloc'
     fork

   - Add the '{make,to}_{upper,lower}case()' methods to 'CStr'/'CString'

   - Add the 'as_ptr' method to 'ThisModule'

   - Add the 'from_raw' method to 'ArcBorrow'

   - Add the 'into_unique_or_drop' method to 'Arc'

   - Display column number in the 'dbg!' macro output by applying the
     equivalent change done to the standard library one

   - Migrate 'Work' to '#[pin_data]' thanks to the changes in the
     'macros' crate, which allows to remove an unsafe call in its 'new'
     associated function

   - Prevent namespacing issues when using the '[try_][pin_]init!'
     macros by changing the generated name of guard variables

   - Make the 'get' method in 'Opaque' const

   - Implement the 'Default' trait for 'LockClassKey'

   - Remove unneeded 'kernel::prelude' imports from doctests

   - Remove redundant imports

  'macros' crate:

   - Add 'decl_generics' to 'parse_generics()' to support default
     values, and use that to allow them in '#[pin_data]'

  Helpers:

   - Trivial English grammar fix

  Documentation:

   - Add section on Rust Kselftests to the 'Testing' document

   - Expand the 'Abstractions vs. bindings' section of the 'General
     Information' document"

* tag 'rust-6.10' of https://github.com/Rust-for-Linux/linux: (31 commits)
  rust: alloc: fix dangling pointer in VecExt<T>::reserve()
  rust: upgrade to Rust 1.78.0
  rust: kernel: remove redundant imports
  rust: sync: implement `Default` for `LockClassKey`
  docs: rust: extend abstraction and binding documentation
  docs: rust: Add instructions for the Rust kselftest
  rust: remove unneeded `kernel::prelude` imports from doctests
  rust: update `dbg!()` to format column number
  rust: helpers: Fix grammar in comment
  rust: init: change the generated name of guard variables
  rust: sync: add `Arc::into_unique_or_drop`
  rust: sync: add `ArcBorrow::from_raw`
  rust: types: Make Opaque::get const
  rust: kernel: remove usage of `allocator_api` unstable feature
  rust: init: update `init` module to take allocation flags
  rust: sync: update `Arc` and `UniqueArc` to take allocation flags
  rust: alloc: update `VecExt` to take allocation flags
  rust: alloc: introduce the `BoxExt` trait
  rust: alloc: introduce allocation flags
  rust: alloc: remove our fork of the `alloc` crate
  ...
2024-05-13 15:13:54 -07:00
Aswin Unnikrishnan
19843452dc rust: remove params from module macro example
Remove argument `params` from the `module` macro example, because the
macro does not currently support module parameters since it was not sent
with the initial merge.

Signed-off-by: Aswin Unnikrishnan <aswinunni01@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Cc: stable@vger.kernel.org
Fixes: 1fbde52bde ("rust: add `macros` crate")
Link: https://lore.kernel.org/r/20240419215015.157258-1-aswinunni01@gmail.com
[ Reworded slightly. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-25 17:34:33 +02:00
Benno Lossin
7044dcff83 rust: macros: fix soundness issue in module! macro
The `module!` macro creates glue code that are called by C to initialize
the Rust modules using the `Module::init` function. Part of this glue
code are the local functions `__init` and `__exit` that are used to
initialize/destroy the Rust module.

These functions are safe and also visible to the Rust mod in which the
`module!` macro is invoked. This means that they can be called by other
safe Rust code. But since they contain `unsafe` blocks that rely on only
being called at the right time, this is a soundness issue.

Wrap these generated functions inside of two private modules, this
guarantees that the public functions cannot be called from the outside.
Make the safe functions `unsafe` and add SAFETY comments.

Cc: stable@vger.kernel.org
Reported-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Closes: https://github.com/Rust-for-Linux/linux/issues/629
Fixes: 1fbde52bde ("rust: add `macros` crate")
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20240401185222.12015-1-benno.lossin@proton.me
[ Moved `THIS_MODULE` out of the private-in-private modules since it
  should remain public, as Dirk Behme noticed [1]. Capitalized comments,
  avoided newline in non-list SAFETY comments and reworded to add
  Reported-by and newline. ]
Link: https://rust-for-linux.zulipchat.com/#narrow/stream/291565-Help/topic/x/near/433512583 [1]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-16 21:13:43 +02:00
Benno Lossin
22eed6068d rust: macros: allow generic parameter default values in #[pin_data]
Add support for generic parameters defaults in `#[pin_data]` by using
the newly introduced `decl_generics` instead of the `impl_generics`.

Before this would not compile:

    #[pin_data]
    struct Foo<const N: usize = 0> {
        // ...
    }

because it would be expanded to this:

    struct Foo<const N: usize = 0> {
        // ...
    }

    const _: () = {
        struct __ThePinData<const N: usize = 0> {
            __phantom: ::core::marker::PhantomData<fn(Foo<N>) -> Foo<N>>,
        }
        impl<const N: usize = 0> ::core::clone::Clone for __ThePinData<N> {
            fn clone(&self) -> Self {
                *self
            }
        }

        // [...] rest of expansion omitted
    };

The problem is with the `impl<const N: usize = 0>`, since that is
invalid Rust syntax. It should not mention the default value at all,
since default values only make sense on type definitions.

The new `impl_generics` do not contain the default values, thus
generating correct Rust code.

This is used by the next commit that puts `#[pin_data]` on
`kernel::workqueue::Work`.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240309155243.482334-2-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-07 22:03:42 +02:00
Benno Lossin
9762dca54a rust: macros: add decl_generics to parse_generics()
The generic parameters on a type definition can specify default values.
Currently `parse_generics()` cannot handle this though. For example when
parsing the following generics:

    <T: Clone, const N: usize = 0>

The `impl_generics` will be set to `T: Clone, const N: usize = 0` and
`ty_generics` will be set to `T, N`. Now using the `impl_generics` on an
impl block:

    impl<$($impl_generics)*> Foo {}

will result in invalid Rust code, because default values are only
available on type definitions.

Therefore add parsing support for generic parameter default values using
a new kind of generics called `decl_generics` and change the old
behavior of `impl_generics` to not contain the generic parameter default
values.

Now `Generics` has three fields:
- `impl_generics`: the generics with bounds
  (e.g. `T: Clone, const N: usize`)
- `decl_generics`: the generics with bounds and default values
  (e.g. `T: Clone, const N: usize = 0`)
- `ty_generics`:  contains the generics without bounds and without
  default values (e.g. `T, N`)

`impl_generics` is designed to be used on `impl<$impl_generics>`,
`decl_generics` for the type definition, so `struct Foo<$decl_generics>`
and `ty_generics` whenever you use the type, so `Foo<$ty_generics>`.

Here is an example that uses all three different types of generics:

    let (Generics { decl_generics, impl_generics, ty_generics }, rest) = parse_generics(input);
    quote! {
        struct Foo<$($decl_generics)*> {
            // ...
        }

        impl<$impl_generics> Foo<$ty_generics> {
            fn foo() {
                // ...
            }
        }
    }

The next commit contains a fix to the `#[pin_data]` macro making it
compatible with generic parameter default values by relying on this new
behavior.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240309155243.482334-1-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-04-07 22:03:42 +02:00
Thomas Bertschinger
1b6170ff7a rust: module: place generated init_module() function in .init.text
Currently Rust kernel modules have their init code placed in the `.text`
section of the .ko file. I don't think this causes any real problems
for Rust modules as long as all code called during initialization lives
in `.text`.

However, if a Rust `init_module()` function (that lives in `.text`)
calls a function marked with `__init` (in C) or
`#[link_section = ".init.text"]` (in Rust), then a warning is
generated by modpost because that function lives in `.init.text`.
For example:

WARNING: modpost: fs/bcachefs/bcachefs: section mismatch in reference: init_module+0x6 (section: .text) -> _RNvXCsj7d3tFpT5JS_15bcachefs_moduleNtB2_8BcachefsNtCsjDtqRIL3JAG_6kernel6Module4init (section: .init.text)

I ran into this while experimenting with converting the bcachefs kernel
module from C to Rust. The module's `init()`, written in Rust, calls C
functions like `bch2_vfs_init()` which are placed in `.init.text`.

This patch places the macro-generated `init_module()` Rust function in
the `.init.text` section. It also marks `init_module()` as unsafe--now
it may not be called after module initialization completes because it
may be freed already.

Note that this is not enough on its own to actually get all the module
initialization code in that section. The module author must still add
the `#[link_section = ".init.text"]` attribute to the Rust `init()` in
the `impl kernel::Module` block in order to then call `__init`
functions. However, this patch enables module authors do so, when
previously it would not be possible (without warnings).

Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240206153806.567055-1-tahbertschinger@gmail.com
[ Reworded title to add prefix. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-02-25 19:17:31 +01:00
Miguel Ojeda
bc2e7d5c29 rust: support srctree-relative links
Some of our links use relative paths in order to point to files in the
source tree, e.g.:

    //! C header: [`include/linux/printk.h`](../../../../include/linux/printk.h)
    /// [`struct mutex`]: ../../../../include/linux/mutex.h

These are problematic because they are hard to maintain and do not support
`O=` builds.

Instead, provide support for `srctree`-relative links, e.g.:

    //! C header: [`include/linux/printk.h`](srctree/include/linux/printk.h)
    /// [`struct mutex`]: srctree/include/linux/mutex.h

The links are fixed after `rustdoc` generation to be based on the absolute
path to the source tree.

Essentially, this is the automatic version of Tomonori's fix [1],
suggested by Gary [2].

Suggested-by: Gary Guo <gary@garyguo.net>
Reported-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Closes: https://lore.kernel.org/r/20231026.204058.2167744626131849993.fujita.tomonori@gmail.com [1]
Fixes: 48fadf4400 ("docs: Move rustdoc output, cross-reference it")
Link: https://lore.kernel.org/rust-for-linux/20231026154525.6d14b495@eugeo/ [2]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20231215235428.243211-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-12-21 20:54:17 +01:00
Benno Lossin
88c2e1169f rust: macros: improve #[vtable] documentation
Traits marked with `#[vtable]` need to provide default implementations
for optional functions. The C side represents these with `NULL` in the
vtable, so the default functions are never actually called. We do not
want to replicate the default behavior from C in Rust, because that is
not maintainable. Therefore we should use `build_error` in those default
implementations. The error message for that is provided at
`kernel::error::VTABLE_DEFAULT_ERROR`.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Finn Behrens <me@kloenk.dev>
Link: https://lore.kernel.org/r/20231026201855.1497680-1-benno.lossin@proton.me
[ Wrapped paragraph to 80 as requested and capitalized sentence. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-12-14 20:14:01 +01:00
Trevor Gross
2dc318ea96 rust: macros: update 'paste!' macro to accept string literals
Enable combining identifiers with literals in the 'paste!' macro. This
allows combining user-specified strings with affixes to create
namespaced identifiers.

This sample code:

    macro_rules! m {
        ($name:lit) => {
            paste!(struct [<_some_ $name _struct_>] {})
        }
    }

    m!("foo_bar");

Would previously cause a compilation error. It will now generate:

    struct _some_foo_bar_struct_ {}

Signed-off-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20231118013959.37384-1-tmgross@umich.edu
[ Added `:` before example block. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-12-14 20:14:01 +01:00
Linus Torvalds
a031fe8d1d Rust changes for v6.6
In terms of lines, most changes this time are on the pinned-init API
 and infrastructure. While we have a Rust version upgrade, and thus a
 bunch of changes from the vendored 'alloc' crate as usual, this time
 those do not account for many lines.
 
 Toolchain and infrastructure:
 
  - Upgrade to Rust 1.71.1. This is the second such upgrade, which is a
    smaller jump compared to the last time.
 
    This version allows us to remove the '__rust_*' allocator functions
    -- the compiler now generates them as expected, thus now our
    'KernelAllocator' is used.
 
    It also introduces the 'offset_of!' macro in the standard library
    (as an unstable feature) which we will need soon. So far, we were
    using a declarative macro as a prerequisite in some not-yet-landed
    patch series, which did not support sub-fields (i.e. nested structs):
 
        #[repr(C)]
        struct S {
            a: u16,
            b: (u8, u8),
        }
 
        assert_eq!(offset_of!(S, b.1), 3);
 
  - Upgrade to bindgen 0.65.1. This is the first time we upgrade its
    version.
 
    Given it is a fairly big jump, it comes with a fair number of
    improvements/changes that affect us, such as a fix needed to support
    LLVM 16 as well as proper support for '__noreturn' C functions, which
    are now mapped to return the '!' type in Rust:
 
        void __noreturn f(void); // C
        pub fn f() -> !;         // Rust
 
  - 'scripts/rust_is_available.sh' improvements and fixes.
 
    This series takes care of all the issues known so far and adds a few
    new checks to cover for even more cases, plus adds some more help
    texts. All this together will hopefully make problematic setups
    easier to identify and to be solved by users building the kernel.
 
    In addition, it adds a test suite which covers all branches of the
    shell script, as well as tests for the issues found so far.
 
  - Support rust-analyzer for out-of-tree modules too.
 
  - Give 'cfg's to rust-analyzer for the 'core' and 'alloc' crates.
 
  - Drop 'scripts/is_rust_module.sh' since it is not needed anymore.
 
 Macros crate:
 
  - New 'paste!' proc macro.
 
    This macro is a more flexible version of 'concat_idents!': it allows
    the resulting identifier to be used to declare new items and it
    allows to transform the identifiers before concatenating them, e.g.
 
        let x_1 = 42;
        paste!(let [<x _2>] = [<x _1>];);
        assert!(x_1 == x_2);
 
    The macro is then used for several of the pinned-init API changes in
    this pull.
 
 Pinned-init API:
 
  - Make '#[pin_data]' compatible with conditional compilation of fields,
    allowing to write code like:
 
        #[pin_data]
        pub struct Foo {
            #[cfg(CONFIG_BAR)]
            a: Bar,
            #[cfg(not(CONFIG_BAR))]
            a: Baz,
        }
 
  - New '#[derive(Zeroable)]' proc macro for the 'Zeroable' trait, which
    allows 'unsafe' implementations for structs where every field
    implements the 'Zeroable' trait, e.g.:
 
        #[derive(Zeroable)]
        pub struct DriverData {
            id: i64,
            buf_ptr: *mut u8,
            len: usize,
        }
 
  - Add '..Zeroable::zeroed()' syntax to the 'pin_init!'  macro for
    zeroing all other fields, e.g.:
 
        pin_init!(Buf {
            buf: [1; 64],
            ..Zeroable::zeroed()
        });
 
  - New '{,pin_}init_array_from_fn()' functions to create array
    initializers given a generator function, e.g.:
 
        let b: Box<[usize; 1_000]> = Box::init::<Error>(
            init_array_from_fn(|i| i)
        ).unwrap();
 
        assert_eq!(b.len(), 1_000);
        assert_eq!(b[123], 123);
 
  - New '{,pin_}chain' methods for '{,Pin}Init<T, E>' that allow to
    execute a closure on the value directly after initialization, e.g.:
 
        let foo = init!(Foo {
            buf <- init::zeroed()
        }).chain(|foo| {
            foo.setup();
            Ok(())
        });
 
  - Support arbitrary paths in init macros, instead of just identifiers
    and generic types.
 
  - Implement the 'Zeroable' trait for the 'UnsafeCell<T>' and
    'Opaque<T>' types.
 
  - Make initializer values inaccessible after initialization.
 
  - Make guards in the init macros hygienic.
 
 'allocator' module:
 
  - Use 'krealloc_aligned()' in 'KernelAllocator::alloc' preventing
    misaligned allocations when the Rust 1.71.1 upgrade is applied later
    in this pull.
 
    The equivalent fix for the previous compiler version (where
    'KernelAllocator' is not yet used) was merged into 6.5 already,
    which added the 'krealloc_aligned()' function used here.
 
  - Implement 'KernelAllocator::{realloc, alloc_zeroed}' for performance,
    using 'krealloc_aligned()' too, which forwards the call to the C API.
 
 'types' module:
 
  - Make 'Opaque' be '!Unpin', removing the need to add a 'PhantomPinned'
    field to Rust structs that contain C structs which must not be moved.
 
  - Make 'Opaque' use 'UnsafeCell' as the outer type, rather than inner.
 
 Documentation:
 
  - Suggest obtaining the source code of the Rust's 'core' library using
    the tarball instead of the repository.
 
 MAINTAINERS:
 
  - Andreas and Alice, from Samsung and Google respectively, are joining
    as reviewers of the "RUST" entry.
 
 As well as a few other minor changes and cleanups.
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Merge tag 'rust-6.6' of https://github.com/Rust-for-Linux/linux

Pull rust updates from Miguel Ojeda:
 "In terms of lines, most changes this time are on the pinned-init API
  and infrastructure. While we have a Rust version upgrade, and thus a
  bunch of changes from the vendored 'alloc' crate as usual, this time
  those do not account for many lines.

  Toolchain and infrastructure:

   - Upgrade to Rust 1.71.1. This is the second such upgrade, which is a
     smaller jump compared to the last time.

     This version allows us to remove the '__rust_*' allocator functions
     -- the compiler now generates them as expected, thus now our
     'KernelAllocator' is used.

     It also introduces the 'offset_of!' macro in the standard library
     (as an unstable feature) which we will need soon. So far, we were
     using a declarative macro as a prerequisite in some not-yet-landed
     patch series, which did not support sub-fields (i.e. nested
     structs):

         #[repr(C)]
         struct S {
             a: u16,
             b: (u8, u8),
         }

         assert_eq!(offset_of!(S, b.1), 3);

   - Upgrade to bindgen 0.65.1. This is the first time we upgrade its
     version.

     Given it is a fairly big jump, it comes with a fair number of
     improvements/changes that affect us, such as a fix needed to
     support LLVM 16 as well as proper support for '__noreturn' C
     functions, which are now mapped to return the '!' type in Rust:

         void __noreturn f(void); // C
         pub fn f() -> !;         // Rust

   - 'scripts/rust_is_available.sh' improvements and fixes.

     This series takes care of all the issues known so far and adds a
     few new checks to cover for even more cases, plus adds some more
     help texts. All this together will hopefully make problematic
     setups easier to identify and to be solved by users building the
     kernel.

     In addition, it adds a test suite which covers all branches of the
     shell script, as well as tests for the issues found so far.

   - Support rust-analyzer for out-of-tree modules too.

   - Give 'cfg's to rust-analyzer for the 'core' and 'alloc' crates.

   - Drop 'scripts/is_rust_module.sh' since it is not needed anymore.

  Macros crate:

   - New 'paste!' proc macro.

     This macro is a more flexible version of 'concat_idents!': it
     allows the resulting identifier to be used to declare new items and
     it allows to transform the identifiers before concatenating them,
     e.g.

         let x_1 = 42;
         paste!(let [<x _2>] = [<x _1>];);
         assert!(x_1 == x_2);

     The macro is then used for several of the pinned-init API changes
     in this pull.

  Pinned-init API:

   - Make '#[pin_data]' compatible with conditional compilation of
     fields, allowing to write code like:

         #[pin_data]
         pub struct Foo {
             #[cfg(CONFIG_BAR)]
             a: Bar,
             #[cfg(not(CONFIG_BAR))]
             a: Baz,
         }

   - New '#[derive(Zeroable)]' proc macro for the 'Zeroable' trait,
     which allows 'unsafe' implementations for structs where every field
     implements the 'Zeroable' trait, e.g.:

         #[derive(Zeroable)]
         pub struct DriverData {
             id: i64,
             buf_ptr: *mut u8,
             len: usize,
         }

   - Add '..Zeroable::zeroed()' syntax to the 'pin_init!' macro for
     zeroing all other fields, e.g.:

         pin_init!(Buf {
             buf: [1; 64],
             ..Zeroable::zeroed()
         });

   - New '{,pin_}init_array_from_fn()' functions to create array
     initializers given a generator function, e.g.:

         let b: Box<[usize; 1_000]> = Box::init::<Error>(
             init_array_from_fn(|i| i)
         ).unwrap();

         assert_eq!(b.len(), 1_000);
         assert_eq!(b[123], 123);

   - New '{,pin_}chain' methods for '{,Pin}Init<T, E>' that allow to
     execute a closure on the value directly after initialization, e.g.:

         let foo = init!(Foo {
             buf <- init::zeroed()
         }).chain(|foo| {
             foo.setup();
             Ok(())
         });

   - Support arbitrary paths in init macros, instead of just identifiers
     and generic types.

   - Implement the 'Zeroable' trait for the 'UnsafeCell<T>' and
     'Opaque<T>' types.

   - Make initializer values inaccessible after initialization.

   - Make guards in the init macros hygienic.

  'allocator' module:

   - Use 'krealloc_aligned()' in 'KernelAllocator::alloc' preventing
     misaligned allocations when the Rust 1.71.1 upgrade is applied
     later in this pull.

     The equivalent fix for the previous compiler version (where
     'KernelAllocator' is not yet used) was merged into 6.5 already,
     which added the 'krealloc_aligned()' function used here.

   - Implement 'KernelAllocator::{realloc, alloc_zeroed}' for
     performance, using 'krealloc_aligned()' too, which forwards the
     call to the C API.

  'types' module:

   - Make 'Opaque' be '!Unpin', removing the need to add a
     'PhantomPinned' field to Rust structs that contain C structs which
     must not be moved.

   - Make 'Opaque' use 'UnsafeCell' as the outer type, rather than
     inner.

  Documentation:

   - Suggest obtaining the source code of the Rust's 'core' library
     using the tarball instead of the repository.

  MAINTAINERS:

   - Andreas and Alice, from Samsung and Google respectively, are
     joining as reviewers of the "RUST" entry.

  As well as a few other minor changes and cleanups"

* tag 'rust-6.6' of https://github.com/Rust-for-Linux/linux: (42 commits)
  rust: init: update expanded macro explanation
  rust: init: add `{pin_}chain` functions to `{Pin}Init<T, E>`
  rust: init: make `PinInit<T, E>` a supertrait of `Init<T, E>`
  rust: init: implement `Zeroable` for `UnsafeCell<T>` and `Opaque<T>`
  rust: init: add support for arbitrary paths in init macros
  rust: init: add functions to create array initializers
  rust: init: add `..Zeroable::zeroed()` syntax for zeroing all missing fields
  rust: init: make initializer values inaccessible after initializing
  rust: init: wrap type checking struct initializers in a closure
  rust: init: make guards in the init macros hygienic
  rust: add derive macro for `Zeroable`
  rust: init: make `#[pin_data]` compatible with conditional compilation of fields
  rust: init: consolidate init macros
  docs: rust: clarify what 'rustup override' does
  docs: rust: update instructions for obtaining 'core' source
  docs: rust: add command line to rust-analyzer section
  scripts: generate_rust_analyzer: provide `cfg`s for `core` and `alloc`
  rust: bindgen: upgrade to 0.65.1
  rust: enable `no_mangle_with_rust_abi` Clippy lint
  rust: upgrade to Rust 1.71.1
  ...
2023-08-29 08:19:46 -07:00
Benno Lossin
071cedc84e rust: add derive macro for Zeroable
Add a derive proc-macro for the `Zeroable` trait. The macro supports
structs where every field implements the `Zeroable` trait. This way
`unsafe` implementations can be avoided.

The macro is split into two parts:
- a proc-macro to parse generics into impl and ty generics,
- a declarative macro that expands to the impl block.

Suggested-by: Asahi Lina <lina@asahilina.net>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230814084602.25699-4-benno.lossin@proton.me
[ Added `ignore` to the `lib.rs` example and cleaned trivial nit. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-21 14:31:48 +02:00
Andrea Righi
41bdc6decd btf, scripts: rust: drop is_rust_module.sh
With commit c1177979af ("btf, scripts: Exclude Rust CUs with pahole")
we are now able to use pahole directly to identify Rust compilation
units (CUs) and exclude them from generating BTF debugging information
(when DEBUG_INFO_BTF is enabled).

And if pahole doesn't support the --lang-exclude flag, we can't enable
both RUST and DEBUG_INFO_BTF at the same time.

So, in any case, the script is_rust_module.sh is just redundant and we
can drop it.

NOTE: we may also be able to drop the "Rust loadable module" mark
inside Rust modules, but it seems safer to keep it for now to make sure
we are not breaking any external tool that may potentially rely on it.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Eric Curtin <ecurtin@redhat.com>
Reviewed-by: Eric Curtin <ecurtin@redhat.com>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Acked-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/20230704052136.155445-1-andrea.righi@canonical.com
[ Picked the `Reviewed-by`s from the old patch too. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-10 22:28:04 +02:00
Gary Guo
823d4737d4 rust: macros: add paste! proc macro
This macro provides a flexible way to concatenated identifiers together
and it allows the resulting identifier to be used to declare new items,
which `concat_idents!` does not allow. It also allows identifiers to be
transformed before concatenated.

The `concat_idents!` example

    let x_1 = 42;
    let x_2 = concat_idents!(x, _1);
    assert!(x_1 == x_2);

can be written with `paste!` macro like this:

    let x_1 = 42;
    let x_2 = paste!([<x _1>]);
    assert!(x_1 == x_2);

However `paste!` macro is more flexible because it can be used to create
a new variable:

    let x_1 = 42;
    paste!(let [<x _2>] = [<x _1>];);
    assert!(x_1 == x_2);

While this is not possible with `concat_idents!`.

This macro is similar to the `paste!` crate [1], but this is a fresh
implementation to avoid vendoring large amount of code directly. Also, I
have augmented it to provide a way to specify span of the resulting
token, allowing precise control.

For example, this code is broken because the variable is declared inside
the macro, so Rust macro hygiene rules prevents access from the outside:

    macro_rules! m {
        ($id: ident) => {
            // The resulting token has hygiene of the macro.
            paste!(let [<$id>] = 1;)
        }
    }

    m!(a);
    let _ = a;

In this version of `paste!` macro I added a `span` modifier to allow
this:

    macro_rules! m {
        ($id: ident) => {
            // The resulting token has hygiene of `$id`.
            paste!(let [<$id:span>] = 1;)
        }
    }

    m!(a);
    let _ = a;

Link: http://docs.rs/paste/ [1]
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230628171108.1150742-1-gary@garyguo.net
[ Added SPDX license identifier as discussed in the list and fixed typo. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-10 22:28:02 +02:00
Qingsong Chen
3fa7187ece rust: macros: vtable: fix HAS_* redefinition (gen_const_name)
If we define the same function name twice in a trait (using `#[cfg]`),
the `vtable` macro will redefine its `gen_const_name`, e.g. this will
define `HAS_BAR` twice:

    #[vtable]
    pub trait Foo {
        #[cfg(CONFIG_X)]
        fn bar();

        #[cfg(not(CONFIG_X))]
        fn bar(x: usize);
    }

Fixes: b44becc5ee ("rust: macros: add `#[vtable]` proc macro")
Signed-off-by: Qingsong Chen <changxian.cqs@antgroup.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Sergio González Collado <sergio.collado@gmail.com>
Link: https://lore.kernel.org/r/20230808025404.2053471-1-changxian.cqs@antgroup.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-09 21:15:07 +02:00
Benno Lossin
52b7bb46ae rust: macros: replace Self with the concrete type in #[pin_data]
When using `#[pin_data]` on a struct that used `Self` in the field
types, a type error would be emitted when trying to use `pin_init!`.
Since an internal type would be referenced by `Self` instead of the
defined struct.

This patch fixes this issue by replacing all occurrences of `Self` in
the `#[pin_data]` macro with the concrete type circumventing the issue.
Since rust allows type definitions inside of blocks, which are
expressions, the macro also checks for these and emits a compile error
when it finds `trait`, `enum`, `union`, `struct` or `impl`. These
keywords allow creating new `Self` contexts, which conflicts with the
current implementation of replacing every `Self` ident. If these were
allowed, some `Self` idents would be replaced incorrectly.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reported-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20230424081112.99890-3-benno.lossin@proton.me
[ Added newline in commit message ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:09 +02:00
Benno Lossin
e957b9cda3 rust: macros: refactor generics parsing of #[pin_data] into its own function
Other macros might also want to parse generics. Additionally this makes
the code easier to read, as the next commit will introduce more code in
`#[pin_data]`. Also add more comments to explain how parsing generics
work.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230424081112.99890-2-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:09 +02:00
Benno Lossin
b8342addde rust: macros: fix usage of #[allow] in quote!
When using `quote!` as part of an expression that was not the last one
in a function, the `#[allow(clippy::vec_init_then_push)]` attribute
would be present on an expression, which is not allowed.
This patch refactors that part of the macro to use a statement instead.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20230424081112.99890-1-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:09 +02:00
Benno Lossin
d0fdc39612 rust: init: add PinnedDrop trait and macros
The `PinnedDrop` trait that facilitates destruction of pinned types.
It has to be implemented via the `#[pinned_drop]` macro, since the
`drop` function should not be called by normal code, only by other
destructors. It also only works on structs that are annotated with
`#[pin_data(PinnedDrop)]`.

Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-10-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Benno Lossin
fc6c6baa1f rust: init: add initialization macros
Add the following initializer macros:
- `#[pin_data]` to annotate structurally pinned fields of structs,
  needed for `pin_init!` and `try_pin_init!` to select the correct
  initializer of fields.
- `pin_init!` create a pin-initializer for a struct with the
  `Infallible` error type.
- `try_pin_init!` create a pin-initializer for a struct with a custom
  error type (`kernel::error::Error` is the default).
- `init!` create an in-place-initializer for a struct with the
  `Infallible` error type.
- `try_init!` create an in-place-initializer for a struct with a custom
  error type (`kernel::error::Error` is the default).

Also add their needed internal helper traits and structs.

Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-8-y86-dev@protonmail.com
[ Fixed three typos. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Gary Guo
70a21e54a4 rust: macros: add quote! macro
Add the `quote!` macro for creating `TokenStream`s directly via the
given Rust tokens. It also supports repetitions using iterators.

It will be used by the pin-init API proc-macros to generate code.

Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-3-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Asahi Lina
46384d0990 rust: error: Rename to_kernel_errno() -> to_errno()
This is kernel code, so specifying "kernel" is redundant. Let's simplify
things and just call it to_errno().

Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Asahi Lina <lina@asahilina.net>
Link: https://lore.kernel.org/r/20230224-rust-error-v3-1-03779bddc02b@asahilina.net
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:04 +02:00
Asahi Lina
39867fec28 rust: macros: Allow specifying multiple module aliases
Modules can (and usually do) have multiple alias tags, in order to
specify multiple possible device matches for autoloading. Allow this by
changing the alias ModuleInfo field to an Option<Vec<String>>.

Note: For normal device IDs this is autogenerated by modpost (which is
not properly integrated with Rust support yet), so it is useful to be
able to manually add device match aliases for now, and should still be
useful in the future for corner cases that modpost does not handle.

This pulls in the expect_group() helper from the rfl/rust branch
(with credit to authors).

Co-developed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Co-developed-by: Finn Behrens <me@kloenk.dev>
Signed-off-by: Finn Behrens <me@kloenk.dev>
Co-developed-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Asahi Lina <lina@asahilina.net>
Link: https://lore.kernel.org/r/20230224-rust-macros-v2-1-7396e8b7018d@asahilina.net
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-10 23:55:43 +02:00
Gary Guo
b13c9880f9 rust: macros: take string literals in module!
Instead of taking binary string literals, take string ones instead,
making it easier for users to define a module, i.e. instead of
calling `module!` like:

    module! {
        ...
        name: b"rust_minimal",
        ...
    }

now it is called as:

    module! {
        ...
        name: "rust_minimal",
        ...
    }

Module names, aliases and license strings are restricted to
ASCII only. However, the author and the description allows UTF-8.

For simplicity (avoid parsing), escape sequences and raw string
literals are not yet handled.

Link: https://github.com/Rust-for-Linux/linux/issues/252
Link: https://lore.kernel.org/lkml/YukvvPOOu8uZl7+n@yadro.com/
Signed-off-by: Gary Guo <gary@garyguo.net>
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-12-04 01:59:15 +01:00
Gary Guo
b44becc5ee rust: macros: add #[vtable] proc macro
This procedural macro attribute provides a simple way to declare
a trait with a set of operations that later users can partially
implement, providing compile-time `HAS_*` boolean associated
constants that indicate whether a particular operation was overridden.

This is useful as the Rust counterpart to structs like
`file_operations` where some pointers may be `NULL`, indicating
an operation is not provided.

For instance:

    #[vtable]
    trait Operations {
        fn read(...) -> Result<usize> {
            Err(EINVAL)
        }

        fn write(...) -> Result<usize> {
            Err(EINVAL)
        }
    }

    #[vtable]
    impl Operations for S {
        fn read(...) -> Result<usize> {
            ...
        }
    }

    assert_eq!(<S as Operations>::HAS_READ, true);
    assert_eq!(<S as Operations>::HAS_WRITE, false);

Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Sergio González Collado <sergio.collado@gmail.com>
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-12-04 01:59:15 +01:00
Björn Roy Baron
60f18c225f rust: macros: add concat_idents! proc macro
This macro provides similar functionality to the unstable feature
`concat_idents` without having to rely on it.

For instance:

    let x_1 = 42;
    let x_2 = concat_idents!(x, _1);
    assert!(x_1 == x_2);

It has different behavior with respect to macro hygiene. Unlike
the unstable `concat_idents!` macro, it allows, for example,
referring to local variables by taking the span of the second
macro as span for the output identifier.

Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Finn Behrens <me@kloenk.dev>
Reviewed-by: Gary Guo <gary@garyguo.net>
[Reworded, adapted for upstream and applied latest changes]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-12-04 01:59:04 +01:00
Miguel Ojeda
1fbde52bde rust: add macros crate
This crate contains all the procedural macros ("proc macros")
shared by all the kernel.

Procedural macros allow to create syntax extensions. They run at
compile-time and can consume as well as produce Rust syntax.

For instance, the `module!` macro that is used by Rust modules
is implemented here. It allows to easily declare the equivalent
information to the `MODULE_*` macros in C modules, e.g.:

    module! {
        type: RustMinimal,
        name: b"rust_minimal",
        author: b"Rust for Linux Contributors",
        description: b"Rust minimal sample",
        license: b"GPL",
    }

Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Finn Behrens <me@kloenk.de>
Signed-off-by: Finn Behrens <me@kloenk.de>
Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Matthew Bakhtiari <dev@mtbk.me>
Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-09-28 08:58:00 +02:00