Commit Graph

132 Commits

Author SHA1 Message Date
Benno Lossin a58f5fabca rust: types: make `Opaque` be `!Unpin`
[ Upstream commit 0b4e3b6f6b ]

Adds a `PhantomPinned` field to `Opaque<T>`. This removes the last Rust
guarantee: the assumption that the type `T` can be freely moved. This is
not the case for many types from the C side (e.g. if they contain a
`struct list_head`). This change removes the need to add a
`PhantomPinned` field manually to Rust structs that contain C structs
which must not be moved.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230630150216.109789-1-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-08 14:09:04 +01:00
Alice Ryhl 7fba72536e rust: make `UnsafeCell` the outer type in `Opaque`
[ Upstream commit 35cad617df ]

When combining `UnsafeCell` with `MaybeUninit`, it is idiomatic to use
`UnsafeCell` as the outer type. Intuitively, this is because a
`MaybeUninit<T>` might not contain a `T`, but we always want the effect
of the `UnsafeCell`, even if the inner value is uninitialized.

Now, strictly speaking, this doesn't really make a difference. The
compiler will always apply the `UnsafeCell` effect even if the inner
value is uninitialized. But I think we should follow the convention
here.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-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/20230614115328.2825961-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Stable-dep-of: 0b4e3b6f6b ("rust: types: make `Opaque` be `!Unpin`")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-08 14:09:03 +01:00
Miguel Ojeda 69cd191012 rust: docs: fix logo replacement
[ Upstream commit cfd96726e6 ]

The static files placement by `rustdoc` changed in Rust 1.67.0 [1],
but the custom code we have to replace the logo in the generated
HTML files did not get updated.

Thus update it to have the Linux logo again in the output.

Hopefully `rustdoc` will eventually support a custom logo from
a local file [2], so that we do not need to maintain this hack
on our side.

Link: https://github.com/rust-lang/rust/pull/101702 [1]
Link: https://github.com/rust-lang/rfcs/pull/3226 [2]
Fixes: 3ed03f4da0 ("rust: upgrade to Rust 1.68.2")
Cc: stable@vger.kernel.org
Tested-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20231018155527.1015059-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-25 12:16:29 +02:00
Carlos Bilbao 43f4e8e32b docs: Move rustdoc output, cross-reference it
[ Upstream commit 48fadf4400 ]

Generate rustdoc documentation with the rest of subsystem's documentation
in Documentation/output. Add a cross reference to the generated rustdoc in
Documentation/rust/index.rst if Sphinx target rustdoc is set.

Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230718151534.4067460-2-carlos.bilbao@amd.com
Stable-dep-of: cfd96726e6 ("rust: docs: fix logo replacement")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-10-25 12:16:29 +02:00
Wedson Almeida Filho 0236504746 rust: error: fix the description for `ECHILD`
commit 17bfcd6a81 upstream.

A mistake was made and the description of `ECHILD` is wrong (it reuses
the description of `ENOEXEC`). This fixes it to reflect what's in
`errno-base.h`.

Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Finn Behrens <me@kloenk.dev>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Fixes: 266def2a0f ("rust: error: add codes from `errno-base.h`")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230930144958.46051-1-wedsonaf@gmail.com
[ Use the plural, as noticed by Benno. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-25 12:16:28 +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
Andrea Righi b055448843 rust: fix bindgen build error with UBSAN_BOUNDS_STRICT
With commit 2d47c6956a ("ubsan: Tighten UBSAN_BOUNDS on GCC") if
CONFIG_UBSAN is enabled and gcc supports -fsanitize=bounds-strict, we
can trigger the following build error due to bindgen lacking support for
this additional build option:

   BINDGEN rust/bindings/bindings_generated.rs
 error: unsupported argument 'bounds-strict' to option '-fsanitize='

Fix by adding -fsanitize=bounds-strict to the list of skipped gcc flags
for bindgen.

Fixes: 2d47c6956a ("ubsan: Tighten UBSAN_BOUNDS on GCC")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230711071914.133946-1-andrea.righi@canonical.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-04 17:10:50 +02:00
Alice Ryhl 1d24eb2d53 rust: delete `ForeignOwnable::borrow_mut`
We discovered that the current design of `borrow_mut` is problematic.
This patch removes it until a better solution can be found.

Specifically, the current design gives you access to a `&mut T`, which
lets you change where the `ForeignOwnable` points (e.g., with
`core::mem::swap`). No upcoming user of this API intended to make that
possible, making all of them unsound.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Fixes: 0fc4424d24 ("rust: types: introduce `ForeignOwnable`")
Link: https://lore.kernel.org/r/20230706094615.3080784-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-04 17:10:50 +02:00
Boqun Feng b3d8aa84bb rust: allocator: Prevent mis-aligned allocation
Currently the rust allocator simply passes the size of the type Layout
to krealloc(), and in theory the alignment requirement from the type
Layout may be larger than the guarantee provided by SLAB, which means
the allocated object is mis-aligned.

Fix this by adjusting the allocation size to the nearest power of two,
which SLAB always guarantees a size-aligned allocation. And because Rust
guarantees that the original size must be a multiple of alignment and
the alignment must be a power of two, then the alignment requirement is
satisfied.

Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Co-developed-by: "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
Signed-off-by: "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Cc: stable@vger.kernel.org # v6.1+
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Fixes: 247b365dc8 ("rust: add `kernel` crate")
Link: https://github.com/Rust-for-Linux/linux/issues/974
Link: https://lore.kernel.org/r/20230730012905.643822-2-boqun.feng@gmail.com
[ Applied rewording of comment as discussed in the mailing list. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-04 17:10:31 +02:00
Gary Guo d2e3115d71 rust: error: `impl Debug` for `Error` with `errname()` integration
Integrate the `Error` type with `errname()` by providing a new
`name()` method.

Then, implement `Debug` for the type using the new method.

[ Miguel: under `CONFIG_SYMBOLIC_ERRNAME=n`, `errname()` is a
  `static inline`, so added a helper to support that case,
  like we had in the `rust` branch. Also moved `#include` up
  and reworded commit message for clarity. ]

Co-developed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230531174450.3733220-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-06-13 01:24:42 +02:00
Alice Ryhl d09a61024f rust: task: add `Send` marker to `Task`
When a type also implements `Sync`, the meaning of `Send` is just "this
type may be accessed mutably from threads other than the one it is
created on". That's ok for this type.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230531145939.3714886-5-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl be7724cdbb rust: specify when `ARef` is thread safe
An `ARef` behaves just like the `Arc` when it comes to thread safety, so
we can reuse the thread safety comments from `Arc` here.

This is necessary because without this change, the Rust compiler will
assume that things are not thread safe even though they are.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230531145939.3714886-4-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl d701e061cb rust: sync: reword the `Arc` safety comment for `Sync`
The safety comment on `impl Sync for Arc` references the Send safety
comment. This commit avoids that in case the two comments drift apart in
the future.

Suggested-by: Andreas Hindborg <a.hindborg@samsung.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230531145939.3714886-3-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl f8110cd157 rust: sync: reword the `Arc` safety comment for `Send`
The safety comment on `impl Send for Arc` talks about "directly"
accessing the value, when it really means "accessing the value with a
mutable reference". This commit clarifies that.

Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230531145939.3714886-2-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl 47329ba14b rust: sync: implement `AsRef<T>` for `Arc<T>`
This trait lets you use `Arc<T>` in code that is generic over smart
pointer types.

The `AsRef` trait should be implemented on all smart pointers. The
standard library also implements it on the ordinary `Arc`.

Co-developed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230517200814.3157916-2-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl bd780aea67 rust: sync: add `Arc::ptr_eq`
Add a method for comparing whether two `Arc` pointers reference the same
underlying object.

This comparison can already be done by getting a reference to the inner
values and comparing whether the references have the same address.
However, writing `Arc::ptr_eq(a, b)` is generally less error-prone than
doing the same check on the references, since you might otherwise
accidentally compare the two `&Arc<T>` references instead, which wont
work because those are pointers to pointers to the inner value, when you
just want to compare the pointers to the inner value.

Also, this method might optimize better because getting a reference to
the inner value involves offsetting the pointer, which this method does
not need to do.

Co-developed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230517200814.3157916-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl e37b654c37 rust: error: add missing error codes
This adds the error codes from `include/linux/errno.h` to the list of
Rust error constants. These errors were not included originally, because
they are not supposed to be visible from userspace. However, they are
still a perfectly valid error to use when writing a kernel driver. For
example, you might want to return ERESTARTSYS if you receive a signal
during a call to `schedule`.

This patch inserts an annotation to skip rustfmt on the list of error
codes. Without it, three of the error codes are split over several
lines, which looks terribly inconsistent.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230504064854.774820-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl 66bd7533ef rust: str: add conversion from `CStr` to `CString`
These methods can be used to copy the data in a temporary c string into
a separate allocation, so that it can be accessed later even if the
original is deallocated.

The API in this change mirrors the standard library API for the `&str`
and `String` types. The `ToOwned` trait is not implemented because it
assumes that allocations are infallible.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230503141016.683634-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Alice Ryhl 4a59081c09 rust: error: allow specifying error type on `Result`
Currently, if the `kernel::error::Result` type is in scope (which is
often is, since it's in the kernel's prelude), you cannot write
`Result<T, SomeOtherErrorType>` when you want to use a different error
type than `kernel::error::Error`.

To solve this we change the error type from being hard-coded to just
being a default generic parameter. This still lets you write `Result<T>`
when you just want to use the `Error` error type, but also lets you
write `Result<T, SomeOtherErrorType>` when necessary.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Asahi Lina <lina@asahilina.net>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20230502124015.356001-1-aliceryhl@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +02:00
Benno Lossin 309786c239 rust: init: update macro expansion example in docs
Also improve the explaining comments.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230424081112.99890-4-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 18:53:10 +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
Miguel Ojeda 3ed03f4da0 rust: upgrade to Rust 1.68.2
This is the first upgrade to the Rust toolchain since the initial Rust
merge, from 1.62.0 to 1.68.2 (i.e. the latest).

# Context

The kernel currently supports only a single Rust version [1] (rather
than a minimum) given our usage of some "unstable" Rust features [2]
which do not promise backwards compatibility.

The goal is to reach a point where we can declare a minimum version for
the toolchain. For instance, by waiting for some of the features to be
stabilized. Therefore, the first minimum Rust version that the kernel
will support is "in the future".

# Upgrade policy

Given we will eventually need to reach that minimum version, it would be
ideal to upgrade the compiler from time to time to be as close as
possible to that goal and find any issues sooner. In the extreme, we
could upgrade as soon as a new Rust release is out. Of course, upgrading
so often is in stark contrast to what one normally would need for GCC
and LLVM, especially given the release schedule: 6 weeks for Rust vs.
half a year for LLVM and a year for GCC.

Having said that, there is no particular advantage to updating slowly
either: kernel developers in "stable" distributions are unlikely to be
able to use their distribution-provided Rust toolchain for the kernel
anyway [3]. Instead, by routinely upgrading to the latest instead,
kernel developers using Linux distributions that track the latest Rust
release may be able to use those rather than Rust-provided ones,
especially if their package manager allows to pin / hold back /
downgrade the version for some days during windows where the version may
not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide
and track the latest version of Rust as they get released every 6 weeks.

Then, when the minimum version is reached, we will stop upgrading and
decide how wide the window of support will be. For instance, a year of
Rust versions. We will probably want to start small, and then widen it
over time, just like the kernel did originally for LLVM, see commit
3519c4d6e0 ("Documentation: add minimum clang/llvm version").

# Unstable features stabilized

This upgrade allows us to remove the following unstable features since
they were stabilized:

  - `feature(explicit_generic_args_with_impl_trait)` (1.63).
  - `feature(core_ffi_c)` (1.64).
  - `feature(generic_associated_types)` (1.65).
  - `feature(const_ptr_offset_from)` (1.65, *).
  - `feature(bench_black_box)` (1.66, *).
  - `feature(pin_macro)` (1.68).

The ones marked with `*` apply only to our old `rust` branch, not
mainline yet, i.e. only for code that we may potentially upstream.

With this patch applied, the only unstable feature allowed to be used
outside the `kernel` crate is `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [2] for details.

# Other required changes

Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for
links pointing to exported (`#[macro_export]`) `macro_rules`. An issue
was opened upstream [4], but it turns out it is intended behavior. For
the moment, just add an explicit reference for each link. Later we can
revisit this if `rustdoc` removes the compatibility measure.

Nevertheless, this was helpful to discover a link that was pointing to
the wrong place unintentionally. Since that one was actually wrong, it
is fixed in a previous commit independently.

Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in
upstream [5], thus remove our original changes for that.

Similarly, upstream now tests that it compiles successfully with
`#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid
of some changes, such as an `#[allow(dead_code)]`.

In addition, remove another `#[allow(dead_code)]` due to new uses
within the standard library.

Finally, add `try_extend_trusted` and move the code in `spec_extend.rs`
since upstream moved it for the infallible version.

# `alloc` upgrade and reviewing

There are a large amount of changes, but the vast majority of them are
due to our `alloc` fork being upgraded at once.

There are two kinds of changes to be aware of: the ones coming from
upstream, which we should follow as closely as possible, and the updates
needed in our added fallible APIs to keep them matching the newer
infallible APIs coming from upstream.

Instead of taking a look at the diff of this patch, an alternative
approach is reviewing a diff of the changes between upstream `alloc` and
the kernel's. This allows to easily inspect the kernel additions only,
especially to check if the fallible methods we already have still match
the infallible ones in the new version coming from upstream.

Another approach is reviewing the changes introduced in the additions in
the kernel fork between the two versions. This is useful to spot
potentially unintended changes to our additions.

To apply these approaches, one may follow steps similar to the following
to generate a pair of patches that show the differences between upstream
Rust and the kernel (for the subset of `alloc` we use) before and after
applying this patch:

    # Get the difference with respect to the old version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > old.patch
    git -C linux restore rust/alloc

    # Apply this patch.
    git -C linux am rust-upgrade.patch

    # Get the difference with respect to the new version.
    git -C rust checkout $(linux/scripts/min-tool-version.sh rustc)
    git -C linux ls-tree -r --name-only HEAD -- rust/alloc |
        cut -d/ -f3- |
        grep -Fv README.md |
        xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH
    git -C linux diff --patch-with-stat --summary -R > new.patch
    git -C linux restore rust/alloc

Now one may check the `new.patch` to take a look at the additions (first
approach) or at the difference between those two patches (second
approach). For the latter, a side-by-side tool is recommended.

Link: https://rust-for-linux.com/rust-version-policy [1]
Link: https://github.com/Rust-for-Linux/linux/issues/2 [2]
Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3]
Link: https://github.com/rust-lang/rust/issues/106142 [4]
Link: https://github.com/rust-lang/rust/pull/89891 [5]
Link: https://github.com/rust-lang/rust/pull/98652 [6]
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org
[ Removed `feature(core_ffi_c)` from `uapi` ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 17:35:03 +02:00
Miguel Ojeda eed7a146b8 rust: arc: fix intra-doc link in `Arc<T>::init`
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link
using the text `pin_init`, rather than more explicitly, which makes
`rustdoc` point it to the `pin_init!` macro instead.

This is required for the compiler upgrade since the newer `rustdoc`
would trigger the `broken_intra_doc_links` lint [1], but in this case
the macro was not the intended target to begin with, and so the actual
fix is to make it point to the right place, regardless of the upgrade.

Thus make it more explicit.

Fixes: 92c4a1e7e8 ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers")
Link: https://github.com/rust-lang/rust/issues/106142 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 16:12:06 +02:00
Miguel Ojeda f438c1dd9e rust: alloc: clarify what is the upstream version
It may be unclear for readers which upstream Rust version these files
are based on. They may be unaware that they are intended to match the
minimum (and only, so far) supported version of Rust in the kernel.

Thus clarify it.

Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Tested-by: Ariel Miculas <amiculas@cisco.com>
Tested-by: David Gow <davidgow@google.com>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20230418214347.324156-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31 16:12:06 +02:00
Linus Torvalds 310897659c Rust changes for v6.4
More additions to the Rust core. Importantly, this adds the pin-init
 API, which will be used by other abstractions, such as the
 synchronization ones added here too:
 
   - pin-init API: a solution for the safe pinned initialization problem.
     This allows to reduce the need for 'unsafe' code in the kernel when
     dealing with data structures that require a stable address. Commit
     90e53c5e70 ("rust: add pin-init API core") contains a nice
     introduction -- here is an example of how it looks like:
 
         #[pin_data]
         struct Example {
             #[pin]
             value: Mutex<u32>,
 
             #[pin]
             value_changed: CondVar,
         }
 
         impl Example {
             fn new() -> impl PinInit<Self> {
                 pin_init!(Self {
                     value <- new_mutex!(0),
                     value_changed <- new_condvar!(),
                 })
             }
         }
 
         // In a `Box`.
         let b = Box::pin_init(Example::new())?;
 
         // In the stack.
         stack_pin_init!(let s = Example::new());
 
   - 'sync' module: new types 'LockClassKey' ('struct lock_class_key'),
     'Lock', 'Guard', 'Mutex' ('struct mutex'), 'SpinLock'
     ('spinlock_t'), 'LockedBy' and 'CondVar' (uses 'wait_queue_head_t'),
     plus macros such as 'static_lock_class!' and 'new_spinlock!'.
 
     In particular, 'Lock' and 'Guard' are generic implementations that
     contain code that is common to all locks. Then, different backends
     (the new 'Backend' trait) are implemented and used to define types
     like 'Mutex':
 
         type Mutex<T> = Lock<T, MutexBackend>;
 
     In addition, new methods 'assume_init()', 'init_with()' and
     'pin_init_with()' for 'UniqueArc<MaybeUninit<T>>' and 'downcast()'
     for 'Arc<dyn Any + Send + Sync>'; as well as 'Debug' and 'Display'
     implementations for 'Arc' and 'UniqueArc'. Reduced stack usage of
     'UniqueArc::try_new_uninit()', too.
 
   - 'types' module: new trait 'AlwaysRefCounted' and new type 'ARef'
     (an owned reference to an always-reference-counted object, meant to
     be used in wrappers for C types that have their own ref counting
     functions).
 
     Moreover, new associated functions 'raw_get()' and 'ffi_init()'
     for 'Opaque'.
 
   - New 'task' module with a new type 'Task' ('struct task_struct'), and
     a new macro 'current!' to safely get a reference to the current one.
 
   - New 'ioctl' module with new '_IOC*' const functions (equivalent to
     the C macros).
 
   - New 'uapi' crate, intended to be accessible by drivers directly.
 
   - 'macros' crate: new 'quote!' macro (similar to the one provided in
     userspace by the 'quote' crate); and the 'module!' macro now allows
     specifying multiple module aliases.
 
   - 'error' module: new associated functions for the 'Error' type,
     such as 'from_errno()' and new functions such as 'to_result()'.
 
   - 'alloc' crate: more fallible 'Vec' methods: 'try_resize` and
     'try_extend_from_slice' and the infrastructure (imported from
     the Rust standard library) they need.
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Merge tag 'rust-6.4' of https://github.com/Rust-for-Linux/linux

Pull rust updates from Miguel Ojeda
 "More additions to the Rust core. Importantly, this adds the pin-init
  API, which will be used by other abstractions, such as the
  synchronization ones added here too:

   - pin-init API: a solution for the safe pinned initialization
     problem.

     This allows to reduce the need for 'unsafe' code in the kernel when
     dealing with data structures that require a stable address. Commit
     90e53c5e70 ("rust: add pin-init API core") contains a nice
     introduction -- here is an example of how it looks like:

        #[pin_data]
        struct Example {
            #[pin]
            value: Mutex<u32>,

            #[pin]
            value_changed: CondVar,
        }

        impl Example {
            fn new() -> impl PinInit<Self> {
                pin_init!(Self {
                    value <- new_mutex!(0),
                    value_changed <- new_condvar!(),
                })
            }
        }

        // In a `Box`.
        let b = Box::pin_init(Example::new())?;

        // In the stack.
        stack_pin_init!(let s = Example::new());

   - 'sync' module:

     New types 'LockClassKey' ('struct lock_class_key'), 'Lock',
     'Guard', 'Mutex' ('struct mutex'), 'SpinLock' ('spinlock_t'),
     'LockedBy' and 'CondVar' (uses 'wait_queue_head_t'), plus macros
     such as 'static_lock_class!' and 'new_spinlock!'.

     In particular, 'Lock' and 'Guard' are generic implementations that
     contain code that is common to all locks. Then, different backends
     (the new 'Backend' trait) are implemented and used to define types
     like 'Mutex':

        type Mutex<T> = Lock<T, MutexBackend>;

     In addition, new methods 'assume_init()', 'init_with()' and
     'pin_init_with()' for 'UniqueArc<MaybeUninit<T>>' and 'downcast()'
     for 'Arc<dyn Any + Send + Sync>'; as well as 'Debug' and 'Display'
     implementations for 'Arc' and 'UniqueArc'. Reduced stack usage of
     'UniqueArc::try_new_uninit()', too.

   - 'types' module:

     New trait 'AlwaysRefCounted' and new type 'ARef' (an owned
     reference to an always-reference-counted object, meant to be used
     in wrappers for C types that have their own ref counting
     functions).

     Moreover, new associated functions 'raw_get()' and 'ffi_init()' for
     'Opaque'.

   - New 'task' module with a new type 'Task' ('struct task_struct'),
     and a new macro 'current!' to safely get a reference to the current
     one.

   - New 'ioctl' module with new '_IOC*' const functions (equivalent to
     the C macros).

   - New 'uapi' crate, intended to be accessible by drivers directly.

   - 'macros' crate: new 'quote!' macro (similar to the one provided in
     userspace by the 'quote' crate); and the 'module!' macro now allows
     specifying multiple module aliases.

   - 'error' module:

     New associated functions for the 'Error' type, such as
     'from_errno()' and new functions such as 'to_result()'.

   - 'alloc' crate:

     More fallible 'Vec' methods: 'try_resize` and
     'try_extend_from_slice' and the infrastructure (imported from the
     Rust standard library) they need"

* tag 'rust-6.4' of https://github.com/Rust-for-Linux/linux: (44 commits)
  rust: ioctl: Add ioctl number manipulation functions
  rust: uapi: Add UAPI crate
  rust: sync: introduce `CondVar`
  rust: lock: add `Guard::do_unlocked`
  rust: sync: introduce `LockedBy`
  rust: introduce `current`
  rust: add basic `Task`
  rust: introduce `ARef`
  rust: lock: introduce `SpinLock`
  rust: lock: introduce `Mutex`
  rust: sync: introduce `Lock` and `Guard`
  rust: sync: introduce `LockClassKey`
  MAINTAINERS: add Benno Lossin as Rust reviewer
  rust: init: broaden the blanket impl of `Init`
  rust: sync: add functions for initializing `UniqueArc<MaybeUninit<T>>`
  rust: sync: reduce stack usage of `UniqueArc::try_new_uninit`
  rust: types: add `Opaque::ffi_init`
  rust: prelude: add `pin-init` API items to prelude
  rust: init: add `Zeroable` trait and `init::zeroed` function
  rust: init: add `stack_pin_init!` macro
  ...
2023-04-30 11:20:22 -07:00
Asahi Lina ea76e08f4d rust: ioctl: Add ioctl number manipulation functions
Add simple 1:1 wrappers of the C ioctl number manipulation functions.
Since these are macros we cannot bindgen them directly, and since they
should be usable in const context we cannot use helper wrappers, so
we'll have to reimplement them in Rust. Thankfully, the C headers do
declare defines for the relevant bitfield positions, so we don't need
to duplicate that.

Signed-off-by: Asahi Lina <lina@asahilina.net>
Link: https://lore.kernel.org/r/20230329-rust-uapi-v2-2-bca5fb4d4a12@asahilina.net
[ Moved the `#![allow(non_snake_case)]` to the usual place. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 01:46:45 +02:00
Asahi Lina 4e17466568 rust: uapi: Add UAPI crate
This crate mirrors the `bindings` crate, but will contain only UAPI
bindings. Unlike the bindings crate, drivers may directly use this crate
if they have to interface with userspace.

Initially, just bind the generic ioctl stuff.

In the future, we would also like to add additional checks to ensure
that all types exposed by this crate satisfy UAPI-safety guarantees
(that is, they are safely castable to/from a "bag of bits").

[ Miguel: added support for the `rustdoc` and `rusttest` targets,
  since otherwise they fail, and we want to keep them working. ]

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Asahi Lina <lina@asahilina.net>
Link: https://lore.kernel.org/r/20230329-rust-uapi-v2-1-bca5fb4d4a12@asahilina.net
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 01:46:45 +02:00
Wedson Almeida Filho 19096bce81 rust: sync: introduce `CondVar`
This is the traditional condition variable or monitor synchronisation
primitive. It is implemented with C's `wait_queue_head_t`.

It allows users to release a lock and go to sleep while guaranteeing
that notifications won't be missed. This is achieved by enqueuing a wait
entry before releasing the lock.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20230411054543.21278-12-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 01:46:45 +02:00
Wedson Almeida Filho e32cca32c3 rust: lock: add `Guard::do_unlocked`
It releases the lock, executes some function provided by the caller,
then reacquires the lock. This is preparation for the implementation of
condvars, which will sleep after between unlocking and relocking.

We need an explicit `relock` method for primitives like `SpinLock` that
have an irqsave variant: we use the guard state to determine if the lock
was originally acquired with the regular `lock` function or
`lock_irqsave`.

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/rust-for-linux/20230412121431.41627-1-wedsonaf@gmail.com/
[ Removed the irqsave bits as discussed. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 01:46:30 +02:00
Wedson Almeida Filho 7b1f55e3a9 rust: sync: introduce `LockedBy`
This allows us to have data protected by a lock despite not being
wrapped by it. Access is granted by providing evidence that the lock is
held by the caller.

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230411054543.21278-13-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 00:20:00 +02:00
Wedson Almeida Filho 8da7a2b743 rust: introduce `current`
This allows Rust code to get a reference to the current task without
having to increment the refcount, but still guaranteeing memory safety.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230411054543.21278-10-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 00:20:00 +02:00
Wedson Almeida Filho 313c4281bc rust: add basic `Task`
It is an abstraction for C's `struct task_struct`. It implements
`AlwaysRefCounted`, so the refcount of the wrapped object is managed
safely on the Rust side.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230411054543.21278-9-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 00:20:00 +02:00
Wedson Almeida Filho f1fbd6a864 rust: introduce `ARef`
This is an owned reference to an object that is always ref-counted. This
is meant to be used in wrappers for C types that have their own ref
counting functions, for example, tasks, files, inodes, dentries, etc.

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20230411054543.21278-8-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 00:20:00 +02:00
Wedson Almeida Filho c6d917a498 rust: lock: introduce `SpinLock`
This is the `spinlock_t` lock backend and allows Rust code to use the
kernel spinlock idiomatically.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230419174426.132207-1-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 00:20:00 +02:00
Wedson Almeida Filho 6d20d629c6 rust: lock: introduce `Mutex`
This is the `struct mutex` lock backend and allows Rust code to use the
kernel mutex idiomatically.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230411054543.21278-3-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 00:20:00 +02:00
Wedson Almeida Filho 76d4bd591e rust: sync: introduce `Lock` and `Guard`
They are generic Rust implementations of a lock and a lock guard that
contain code that is common to all locks. Different backends will be
introduced in subsequent commits.

Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Suggested-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230411054543.21278-2-wedsonaf@gmail.com
[ Fixed typo. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-22 00:19:42 +02:00
Wedson Almeida Filho 6ea5aa0885 rust: sync: introduce `LockClassKey`
It is a wrapper around C's `lock_class_key`, which is used by the
synchronisation primitives that are checked with lockdep. This is in
preparation for introducing Rust abstractions for these primitives.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20230411054543.21278-1-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-21 00:35:26 +02:00
Benno Lossin 52a7f2deb4 rust: init: broaden the blanket impl of `Init`
This makes it possible to use `T` as a `impl Init<T, E>` for every error
type `E` instead of just `Infallible`.

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/20230413100157.740697-1-benno.lossin@proton.me
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-21 00:35:26 +02:00
Andrea Righi d966c3cab9 rust: allow to use INIT_STACK_ALL_ZERO
With CONFIG_INIT_STACK_ALL_ZERO enabled, bindgen passes
-ftrivial-auto-var-init=zero to clang, that triggers the following
error:

 error: '-ftrivial-auto-var-init=zero' hasn't been enabled; enable it at your own peril for benchmarking purpose only with '-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang'

However, this additional option that is currently required by clang is
deprecated since clang-16 and going to be removed in the future,
likely with clang-18.

So, make sure bindgen is using this extra option if the major version of
the libclang used by bindgen is < 16.

In this way we can enable CONFIG_INIT_STACK_ALL_ZERO with CONFIG_RUST
without triggering any build error.

Link: https://github.com/llvm/llvm-project/issues/44842
Link: https://github.com/llvm/llvm-project/blob/llvmorg-16.0.0-rc2/clang/docs/ReleaseNotes.rst#deprecated-compiler-flags
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[Changed to < 16, added link and reworded]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-19 19:34:43 +02:00
Benno Lossin 1944caa8e8 rust: sync: add functions for initializing `UniqueArc<MaybeUninit<T>>`
Add two functions `init_with` and `pin_init_with` to
`UniqueArc<MaybeUninit<T>>` to initialize the memory of already allocated
`UniqueArc`s. This is useful when you want to allocate memory check some
condition inside of a context where allocation is forbidden and then
conditionally initialize an object.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-16-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Benno Lossin 701608bd03 rust: sync: reduce stack usage of `UniqueArc::try_new_uninit`
`UniqueArc::try_new_uninit` calls `Arc::try_new(MaybeUninit::uninit())`.
This results in the uninitialized memory being placed on the stack,
which may be arbitrarily large due to the generic `T` and thus could
cause a stack overflow for large types.

Change the implementation to use the pin-init API which enables in-place
initialization. In particular it avoids having to first construct and
then move the uninitialized memory from the stack into the final location.

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: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-15-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Benno Lossin 692e8935e2 rust: types: add `Opaque::ffi_init`
This function allows to easily initialize `Opaque` with the pin-init
API. `Opaque::ffi_init` takes a closure and returns a pin-initializer.
This pin-initiailizer calls the given closure with a pointer to the
inner `T`.

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: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-14-y86-dev@protonmail.com
[ Fixed typo. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Benno Lossin 8586f1acd3 rust: prelude: add `pin-init` API items to prelude
Add `pin-init` API macros and traits to the prelude.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-13-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Benno Lossin 38cde0bd7b rust: init: add `Zeroable` trait and `init::zeroed` function
Add the `Zeroable` trait which marks types that can be initialized by
writing `0x00` to every byte of the type. Also add the `init::zeroed`
function that creates an initializer for a `Zeroable` type that writes
`0x00` to every byte.

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: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-12-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +02:00
Benno Lossin 6841d45a30 rust: init: add `stack_pin_init!` macro
The `stack_pin_init!` macro allows pin-initializing a value on the
stack. It accepts a `impl PinInit<T, E>` to initialize a `T`. It allows
propagating any errors via `?` or handling it normally via `match`.

Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20230408122429.1103522-11-y86-dev@protonmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-04-12 18:41:05 +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 92c4a1e7e8 rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers
The `InPlaceInit` trait that provides two functions, for initializing
using `PinInit<T, E>` and `Init<T>`. It is implemented by `Arc<T>`,
`UniqueArc<T>` and `Box<T>`.

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: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20230408122429.1103522-9-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