Commit Graph

188 Commits

Author SHA1 Message Date
Mitchell Levy
50b22a98c1 rust: lockdep: Remove support for dynamically allocated LockClassKeys
commit 966944f3711665db13e214fef6d02982c49bb972 upstream.

Currently, dynamically allocated LockCLassKeys can be used from the Rust
side without having them registered. This is a soundness issue, so
remove them.

Fixes: 6ea5aa0885 ("rust: sync: introduce `LockClassKey`")
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250307232717.1759087-11-boqun.feng@gmail.com
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22 12:50:50 -07:00
Alban Kurti
2592a62874 rust: init: add missing newline to pr_info! calls
[ Upstream commit 6933c1067fe6df8ddb34dd68bdb2aa172cbd08c8 ]

Several pr_info! calls in rust/kernel/init.rs (both in code examples
and macro documentation) were missing a newline, causing logs to
run together. This commit updates these calls to include a trailing
newline, improving readability and consistency with the C side.

Fixes: 6841d45a30 ("rust: init: add `stack_pin_init!` macro")
Fixes: 7f8977a7fe ("rust: init: add `{pin_}chain` functions to `{Pin}Init<T, E>`")
Fixes: d0fdc39612 ("rust: init: add `PinnedDrop` trait and macros")
Fixes: 4af84c6a85 ("rust: init: update expanded macro explanation")
Reported-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1139
Signed-off-by: Alban Kurti <kurti@invicto.ai>
Link: https://lore.kernel.org/r/20250206-printing_fix-v3-3-a85273b501ae@invicto.ai
[ Replaced Closes with Link since it fixes part of the issue. Added
  one more Fixes tag (still same set of stable kernels). - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-22 12:50:48 -07:00
Alban Kurti
5da54be469 rust: error: add missing newline to pr_warn! calls
[ Upstream commit 6f5c36f56d475732981dcf624e0ac0cc7c8984c8 ]

Added missing newline at the end of pr_warn! usage
so the log is not missed.

Fixes: 6551a7fe0a ("rust: error: Add Error::from_errno{_unchecked}()")
Reported-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1139
Signed-off-by: Alban Kurti <kurti@invicto.ai>
Link: https://lore.kernel.org/r/20250206-printing_fix-v3-2-a85273b501ae@invicto.ai
[ Replaced Closes with Link since it fixes part of the issue. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-22 12:50:48 -07:00
Benno Lossin
aa4d9b54f1 rust: init: fix Zeroable implementation for Option<NonNull<T>> and Option<KBox<T>>
commit df27cef153603b18a7d094b53cc3d5264ff32797 upstream.

According to [1], `NonNull<T>` and `#[repr(transparent)]` wrapper types
such as our custom `KBox<T>` have the null pointer optimization only if
`T: Sized`. Thus remove the `Zeroable` implementation for the unsized
case.

Link: https://doc.rust-lang.org/stable/std/option/index.html#representation [1]
Reported-by: Alice Ryhl <aliceryhl@google.com>
Closes: https://lore.kernel.org/rust-for-linux/CAH5fLghL+qzrD8KiCF1V3vf2YcC6aWySzkmaE2Zzrnh1gKj-hw@mail.gmail.com/
Cc: stable@vger.kernel.org # v6.12+ (a custom patch will be needed for 6.6.y)
Fixes: 38cde0bd7b ("rust: init: add `Zeroable` trait and `init::zeroed` function")
Signed-off-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250305132836.2145476-1-benno.lossin@proton.me
[ Added Closes tag and moved up the Reported-by one. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-22 12:50:48 -07:00
Miguel Ojeda
6a42d63783 rust: init: use explicit ABI to clean warning in future compilers
commit c21bdb3d8a850afdfa4afe77eea39ae9533629b0 upstream.

Starting with Rust 1.86.0 (currently in nightly, to be released on
2025-04-03), the `missing_abi` lint is warn-by-default [1]:

    error: extern declarations without an explicit ABI are deprecated
        --> rust/doctests_kernel_generated.rs:3158:1
         |
    3158 | extern {
         | ^^^^^^ help: explicitly specify the C ABI: `extern "C"`
         |
         = note: `-D missing-abi` implied by `-D warnings`
         = help: to override `-D warnings` add `#[allow(missing_abi)]`

Thus clean it up.

Cc: <stable@vger.kernel.org> # Needed in 6.12.y and 6.13.y only (Rust is pinned in older LTSs).
Fixes: 7f8977a7fe ("rust: init: add `{pin_}chain` functions to `{Pin}Init<T, E>`")
Link: https://github.com/rust-lang/rust/pull/132397 [1]
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Fiona Behrens <me@kloenk.dev>
Link: https://lore.kernel.org/r/20250121200934.222075-1-ojeda@kernel.org
[ Added 6.13.y to Cc: stable tag. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17 09:40:27 +01:00
Paolo Bonzini
b7c4121a43 rust: macros: fix documentation of the paste! macro
[ Upstream commit 15541c9263ce34ff95a06bc68f45d9bc5c990bcd ]

One of the example in this section uses a curious mix of the constant
and function declaration syntaxes; fix it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Fixes: 823d4737d4 ("rust: macros: add `paste!` proc macro")
Link: https://lore.kernel.org/r/20241019072208.1016707-1-pbonzini@redhat.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-09 10:32:25 +01:00
Alice Ryhl
6fcd6feaf1 rust: sync: require T: Sync for LockedBy::access
commit a8ee30f45d5d57467ddb7877ed6914d0eba0af7f upstream.

The `LockedBy::access` method only requires a shared reference to the
owner, so if we have shared access to the `LockedBy` from several
threads at once, then two threads could call `access` in parallel and
both obtain a shared reference to the inner value. Thus, require that
`T: Sync` when calling the `access` method.

An alternative is to require `T: Sync` in the `impl Sync for LockedBy`.
This patch does not choose that approach as it gives up the ability to
use `LockedBy` with `!Sync` types, which is okay as long as you only use
`access_mut`.

Cc: stable@vger.kernel.org
Fixes: 7b1f55e3a9 ("rust: sync: introduce `LockedBy`")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240915-locked-by-sync-fix-v2-1-1a8d89710392@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-10 11:57:44 +02:00
Andreas Hindborg
b4b2115d1f rust: kbuild: fix export of bss symbols
[ Upstream commit b8673d56935c32a4e0a1a0b40951fdd313dbf340 ]

Symbols in the bss segment are not currently exported. This is a problem
for Rust modules that link against statics, that are resident in the kernel
image. Thus export symbols in the bss segment.

Fixes: 2f7ab1267d ("Kbuild: add Rust support")
Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240815074519.2684107-2-nmi@metaspace.dk
[ Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12 11:11:32 +02:00
Matthew Maurer
4de4e53bbd rust: Use awk instead of recent xargs
[ Upstream commit 45f97e6385cad6d0e48a27ddcd08793bb4d35851 ]

`awk` is already required by the kernel build, and the `xargs` feature
used in current Rust detection is not present in all `xargs` (notably,
toybox based xargs, used in the Android kernel build).

Signed-off-by: Matthew Maurer <mmaurer@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230928205045.2375899-1-mmaurer@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Stable-dep-of: b8673d56935c ("rust: kbuild: fix export of bss symbols")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12 11:11:32 +02:00
Boqun Feng
f9275893b0 rust: macros: provide correct provenance when constructing THIS_MODULE
commit a5a3c952e82c1ada12bf8c55b73af26f1a454bd2 upstream.

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: be2ca1e03965: ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-12 11:11:25 +02:00
Boqun Feng
d6344cc86f rust: types: Make Opaque::get const
commit be2ca1e03965ffb214b6cbda0ffd84daeeb5f214 upstream.

To support a potential usage:

    static foo: Opaque<Foo> = ..; // Or defined in an extern block.

    ...

    fn bar() {
        let ptr = foo.get();
    }

`Opaque::get` need to be `const`, otherwise compiler will complain
because calls on statics are limited to const functions.

Also `Opaque::get` should be naturally `const` since it's a composition
of two `const` functions: `UnsafeCell::get` and `ptr::cast`.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240401214543.1242286-1-boqun.feng@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-12 11:11:25 +02:00
Wedson Almeida Filho
00d2715aaa rust: kernel: require Send for Module implementations
[ Upstream commit 323617f649c0966ad5e741e47e27e06d3a680d8f ]

The thread that calls the module initialisation code when a module is
loaded is not guaranteed [in fact, it is unlikely] to be the same one
that calls the module cleanup code on module unload, therefore, `Module`
implementations must be `Send` to account for them moving from one
thread to another implicitly.

Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Cc: stable@vger.kernel.org # 6.8.x: df70d04d5697: rust: phy: implement `Send` for `Registration`
Cc: stable@vger.kernel.org
Fixes: 247b365dc8 ("rust: add `kernel` crate")
Link: https://lore.kernel.org/r/20240328195457.225001-3-wedsonaf@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 12:01:56 +02:00
Benno Lossin
a4dec33d27 rust: macros: fix soundness issue in module! macro
[ Upstream commit 7044dcff8301b29269016ebd17df27c4736140d2 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 12:01:56 +02:00
Thomas Bertschinger
738ea6d9ca rust: module: place generated init_module() function in .init.text
[ Upstream commit 1b6170ff7a203a5e8354f19b7839fe8b897a9c0d ]

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>
Stable-dep-of: 7044dcff8301 ("rust: macros: fix soundness issue in `module!` macro")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 12:01:55 +02:00
Aswin Unnikrishnan
ece94c74e4 rust: remove params from module macro example
commit 19843452dca40e28d6d3f4793d998b681d505c7f upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-02 16:32:42 +02:00
Miguel Ojeda
2eed4381ee kbuild: rust: remove unneeded @rustc_cfg to avoid ICE
commit 50cfe93b01475ba36878b65d35d812e1bb48ac71 upstream.

When KUnit tests are enabled, under very big kernel configurations
(e.g. `allyesconfig`), we can trigger a `rustdoc` ICE [1]:

      RUSTDOC TK rust/kernel/lib.rs
    error: the compiler unexpectedly panicked. this is a bug.

The reason is that this build step has a duplicated `@rustc_cfg` argument,
which contains the kernel configuration, and thus a lot of arguments. The
factor 2 happens to be enough to reach the ICE.

Thus remove the unneeded `@rustc_cfg`. By doing so, we clean up the
command and workaround the ICE.

The ICE has been fixed in the upcoming Rust 1.79 [2].

Cc: stable@vger.kernel.org
Fixes: a66d733da8 ("rust: support running Rust documentation tests as KUnit ones")
Link: https://github.com/rust-lang/rust/issues/122722 [1]
Link: https://github.com/rust-lang/rust/pull/122840 [2]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240422091215.526688-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-02 16:32:42 +02:00
Laine Taffin Altman
c34a8052af rust: init: remove impl Zeroable for Infallible
commit 49ceae68a0df9a92617a61e9ce8a0efcf6419585 upstream.

In Rust, producing an invalid value of any type is immediate undefined
behavior (UB); this includes via zeroing memory.  Therefore, since an
uninhabited type has no valid values, producing any values at all for it is
UB.

The Rust standard library type `core::convert::Infallible` is uninhabited,
by virtue of having been declared as an enum with no cases, which always
produces uninhabited types in Rust.

The current kernel code allows this UB to be triggered, for example by code
like `Box::<core::convert::Infallible>::init(kernel::init::zeroed())`.

Thus, remove the implementation of `Zeroable` for `Infallible`, thereby
avoiding the unsoundness (potential for future UB).

Cc: stable@vger.kernel.org
Fixes: 38cde0bd7b ("rust: init: add `Zeroable` trait and `init::zeroed` function")
Closes: https://github.com/Rust-for-Linux/pinned-init/pull/13
Signed-off-by: Laine Taffin Altman <alexanderaltman@me.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/CA160A4E-561E-4918-837E-3DCEBA74F808@me.com
[ Reformatted the comment slightly. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-02 16:32:42 +02:00
Miguel Ojeda
73596f5ab3 rust: upgrade to Rust 1.73.0
commit e08ff622c91af997cb89bc47e90a1a383e938bd0 upstream.

This is the next upgrade to the Rust toolchain, from 1.72.1 to 1.73.0
(i.e. the latest) [1].

See the upgrade policy [2] and the comments on the first upgrade in
commit 3ed03f4da0 ("rust: upgrade to Rust 1.68.2").

# Unstable features

No unstable features (that we use) were stabilized.

Therefore, the only unstable feature allowed to be used outside
the `kernel` crate is still `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [3] for details.

# Required changes

For the upgrade, the following changes are required:

  - Allow `internal_features` for `feature(compiler_builtins)` since
    now Rust warns about using internal compiler and standard library
    features (similar to how it also warns about incomplete ones) [4].

  - A cleanup for a documentation link thanks to a new `rustdoc` lint.
    See previous commits for details.

  - A need to make an intra-doc link to a macro explicit, due to a
    change in behavior in `rustdoc`. See previous commits for details.

# `alloc` upgrade and reviewing

The vast majority of changes 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://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1730-2023-10-05 [1]
Link: https://rust-for-linux.com/rust-version-policy [2]
Link: https://github.com/Rust-for-Linux/linux/issues/2 [3]
Link: https://github.com/rust-lang/compiler-team/issues/596 [4]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20231005210556.466856-4-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-16 19:10:43 +01:00
Miguel Ojeda
aacae44644 rust: print: use explicit link in documentation
commit a53d8cdd5a0aec75ae32badc2d8995c59ea6e3f0 upstream.

The future `rustdoc` in the Rust 1.73.0 upgrade requires an explicit
link for `pr_info!`:

    error: unresolved link to `pr_info`
       --> rust/kernel/print.rs:395:63
        |
    395 | /// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
        |                                                               ^^^^^^^^ no item named `pr_info` in scope
        |
        = note: `macro_rules` named `pr_info` exists in this crate, but it is not in scope at this link's location
        = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`

Thus do so to avoid a broken link while upgrading.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Finn Behrens <me@kloenk.dev>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20231005210556.466856-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-16 19:10:43 +01:00
Miguel Ojeda
e8e7a52822 rust: task: remove redundant explicit link
commit c61bcc278b1924da13fd52edbd46b08a518c11ef upstream.

Starting with Rust 1.73.0, `rustdoc` detects redundant explicit
links with its new lint `redundant_explicit_links` [1]:

    error: redundant explicit link target
      --> rust/kernel/task.rs:85:21
       |
    85 |     /// [`current`](crate::current) macro because it is safe.
       |          ---------  ^^^^^^^^^^^^^^ explicit target is redundant
       |          |
       |          because label contains path that resolves to same destination
       |
       = note: when a link's destination is not specified,
               the label is used to resolve intra-doc links
       = note: `-D rustdoc::redundant-explicit-links` implied by `-D warnings`
    help: remove explicit link target
       |
    85 |     /// [`current`] macro because it is safe.

In order to avoid the warning in the compiler upgrade commit,
make it an intra-doc link as the tool suggests.

Link: https://github.com/rust-lang/rust/pull/113167 [1]
Reviewed-by: Finn Behrens <me@kloenk.dev>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Link: https://lore.kernel.org/r/20231005210556.466856-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-16 19:10:43 +01:00
Miguel Ojeda
9b33bb254d rust: upgrade to Rust 1.72.1
commit ae6df65dabc3f8bd89663d96203963323e266d90 upstream.

This is the third upgrade to the Rust toolchain, from 1.71.1 to 1.72.1
(i.e. the latest) [1].

See the upgrade policy [2] and the comments on the first upgrade in
commit 3ed03f4da0 ("rust: upgrade to Rust 1.68.2").

# Unstable features

No unstable features (that we use) were stabilized.

Therefore, the only unstable feature allowed to be used outside
the `kernel` crate is still `new_uninit`, though other code to be
upstreamed may increase the list.

Please see [3] for details.

# Other improvements

Previously, the compiler could incorrectly generate a `.eh_frame`
section under `-Cpanic=abort`. We were hitting this bug when debug
assertions were enabled (`CONFIG_RUST_DEBUG_ASSERTIONS=y`) [4]:

      LD      .tmp_vmlinux.kallsyms1
    ld.lld: error: <internal>:(.eh_frame) is being placed in '.eh_frame'

Gary fixed the issue in Rust 1.72.0 [5].

# Required changes

For the upgrade, the following changes are required:

  - A call to `Box::from_raw` in `rust/kernel/sync/arc.rs` now requires
    an explicit `drop()` call. See previous patch for details.

# `alloc` upgrade and reviewing

The vast majority of changes 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://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1721-2023-09-19 [1]
Link: https://rust-for-linux.com/rust-version-policy [2]
Link: https://github.com/Rust-for-Linux/linux/issues/2 [3]
Closes: https://github.com/Rust-for-Linux/linux/issues/1012 [4]
Link: https://github.com/rust-lang/rust/pull/112403 [5]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Link: https://lore.kernel.org/r/20230823160244.188033-3-ojeda@kernel.org
[ Used 1.72.1 instead of .0 (no changes in `alloc`) and reworded
  to mention that we hit the `.eh_frame` bug under debug assertions. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-16 19:10:43 +01:00
Miguel Ojeda
31a254f692 rust: arc: add explicit drop() around Box::from_raw()
commit 828176d037e29f813792a8b3ac1591834240e96f upstream.

`Box::from_raw()` is `#[must_use]`, which means the result cannot
go unused.

In Rust 1.71.0, this was not detected because the block expression
swallows the diagnostic [1]:

    unsafe { Box::from_raw(self.ptr.as_ptr()) };

It would have been detected, however, if the line had been instead:

    unsafe { Box::from_raw(self.ptr.as_ptr()); }

i.e. the semicolon being inside the `unsafe` block, rather than
outside.

In Rust 1.72.0, the compiler started warning about this [2], so
without this patch we will get:

        error: unused return value of `alloc::boxed::Box::<T>::from_raw` that must be used
        --> rust/kernel/sync/arc.rs:302:22
        |
    302 |             unsafe { Box::from_raw(self.ptr.as_ptr()) };
        |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        |
        = note: call `drop(Box::from_raw(ptr))` if you intend to drop the `Box`
        = note: `-D unused-must-use` implied by `-D warnings`
    help: use `let _ = ...` to ignore the resulting value
        |
    302 |             unsafe { let _ = Box::from_raw(self.ptr.as_ptr()); };
        |                      +++++++                                 +

Thus add an add an explicit `drop()` as the `#[must_use]`'s
annotation suggests (instead of the more general help line).

Link: https://github.com/rust-lang/rust/issues/104253 [1]
Link: https://github.com/rust-lang/rust/pull/112529 [2]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Link: https://lore.kernel.org/r/20230823160244.188033-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-16 19:10:43 +01:00
Matthew Maurer
9853f1307e rust: Ignore preserve-most functions
commit bad098d76835c1379e1cf6afc935f8a7e050f83c upstream.

Neither bindgen nor Rust know about the preserve-most calling
convention, and Clang describes it as unstable. Since we aren't using
functions with this calling convention from Rust, blocklist them.

These functions are only added to the build when list hardening is
enabled, which is likely why others didn't notice this yet.

Signed-off-by: Matthew Maurer <mmaurer@google.com>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20231031201945.1412345-1-mmaurer@google.com
[ Used Markdown for consistency with the other comments in the file. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-25 15:35:41 -08:00
Miguel Ojeda
cfd96726e6 rust: docs: fix logo replacement
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>
2023-10-19 16:40:00 +02:00
Andrea Righi
344b6c0a75 rust: fix bindgen build error with fstrict-flex-arrays
Commit df8fc4e934 ("kbuild: Enable -fstrict-flex-arrays=3") enabled
'-fstrict-flex-arrays=3' globally, but bindgen does not recognized this
compiler option, triggering the following build error:

 error: unknown argument: '-fstrict-flex-arrays=3', err: true

[ Miguel: Commit df8fc4e934 ("kbuild: Enable -fstrict-flex-arrays=3")
  did it so only conditionally (i.e. only if the C compiler supports
  it). This explains what Andrea was seeing: he was  compiling with a
  modern enough GCC, which enables the option, but with an old enough
  Clang. Andrea confirmed this was the case: he was using Clang 14 with
  GCC 13; and that Clang 15 worked for him.

  While it is possible to construct code (see mailing list for an
  example I came up with) where this could break, it is fairly
  contrived, and anyway GCC-built kernels with Rust enabled should
  only be used for experimentation until we get support for
  `rustc_codegen_gcc` and/or GCC Rust. So let's add this for the
  time being in case it helps somebody. ]

Add '-fstrict-flex-arrays' to the list of cflags that should be ignored
by bindgen.

Fixes: df8fc4e934 ("kbuild: Enable -fstrict-flex-arrays=3")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Tested-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20230815065346.131387-1-andrea.righi@canonical.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-10-12 22:58:52 +02:00