linux.git/rust, branch v6.11

rust: macros: provide correct provenance when constructing THIS_MODULE

2024-09-02T07:14:28+00:00

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` 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 
Signed-off-by: Boqun Feng 
Reviewed-by: Alice Ryhl 
Reviewed-by: Trevor Gross 
Reviewed-by: Benno Lossin 
Reviewed-by: Gary Guo 
Closes: https://rust-for-linux.zulipchat.com/#narrow/stream/x/topic/x/near/465412664
Fixes: 1fbde52bde73 ("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

rust: alloc: eschew `Box>::write`

2024-08-26T22:07:05+00:00

Upstream Rust's libs-api team has consensus for stabilizing some of
`feature(new_uninit)`, but not for `Box>::write`. Instead,
we can use `MaybeUninit::write`, so Rust for Linux can drop the
feature after stabilization. That will happen after merging, as the FCP
has completed [1].

This is required before stabilization because remaining-unstable API
will be divided into new features. This code doesn't know about those
yet. It can't: they haven't landed, as the relevant PR is blocked on
rustc's CI testing Rust-for-Linux without this patch.

[ The PR has landed [2] and will be released in Rust 1.82.0 (expected on
  2024-10-17), so we could conditionally enable the new unstable feature
  (`box_uninit_write` [3]) instead, but just for a single `unsafe` block
  it is probably not worth it. For the time being, I added it to the
  "nice to have" section of our unstable features list. - Miguel ]

Link: https://github.com/rust-lang/rust/issues/63291#issuecomment-2183022955 [1]
Link: https://github.com/rust-lang/rust/pull/129416 [2]
Link: https://github.com/rust-lang/rust/issues/129397 [3]
Signed-off-by: Jubilee Young 
Reviewed-by: Alice Ryhl 
Reviewed-by: Trevor Gross 
[ Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: kernel: fix typos in code comments

2024-08-21T11:29:36+00:00

Fix spelling mistakes in code comments.

Signed-off-by: Michael Vetter 
Reviewed-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Link: https://lore.kernel.org/r/20240819205731.2163-1-jubalh@iodoru.org
[ Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: block: fix wrong usage of lockdep API

2024-08-21T11:28:13+00:00

When allocating `struct gendisk`, `GenDiskBuilder` is using a dynamic
lock class key without registering the key. This is an incorrect use of
the API, which causes a `WARN` trace.

Fix the issue by using a static lock class key, which is more appropriate
for the situation anyway.

Fixes: 3253aba3408a ("rust: block: introduce `kernel::block::mq` module")
Reported-by: Behme Dirk (XC-CP/ESB5) 
Closes: https://rust-for-linux.zulipchat.com/#narrow/stream/x/topic/x/near/457090036
Signed-off-by: Andreas Hindborg 
Reviewed-by: Benno Lossin 
Reviewed-by: Gary Guo 
Reviewed-by: Alice Ryhl 
Tested-by: Dirk Behme 
Link: https://lore.kernel.org/r/20240815074519.2684107-3-nmi@metaspace.dk
[ Applied `rustfmt`, reworded slightly and made Zulip link
  a permalink. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: kbuild: fix export of bss symbols

2024-08-20T23:24:10+00:00

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: 2f7ab1267dc9 ("Kbuild: add Rust support")
Signed-off-by: Andreas Hindborg 
Reviewed-by: Alice Ryhl 
Tested-by: Alice Ryhl 
Reviewed-by: Gary Guo 
Link: https://lore.kernel.org/r/20240815074519.2684107-2-nmi@metaspace.dk
[ Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda

Merge tag 'rust-fixes-6.11' of https://github.com/Rust-for-Linux/linux

2024-08-16T18:24:06+00:00

Pull rust fixes from Miguel Ojeda:

 - Fix '-Os' Rust 1.80.0+ builds adding more intrinsics (also tweaked in
   upstream Rust for the upcoming 1.82.0).

 - Fix support for the latest version of rust-analyzer due to a change
   on rust-analyzer config file semantics (considered a fix since most
   developers use the latest version of the tool, which is the only one
   actually supported by upstream). I am discussing stability of the
   config file with upstream -- they may be able to start versioning it.

 - Fix GCC 14 builds due to '-fmin-function-alignment' not skipped for
   libclang (bindgen).

 - A couple Kconfig fixes around '{RUSTC,BINDGEN}_VERSION_TEXT' to
   suppress error messages in a foreign architecture chroot and to use a
   proper default format.

 - Clean 'rust-analyzer' target warning due to missing recursive make
   invocation mark.

 - Clean Clippy warning due to missing indentation in docs.

 - Clean LLVM 19 build warning due to removed 3dnow feature upstream.

* tag 'rust-fixes-6.11' of https://github.com/Rust-for-Linux/linux:
  rust: x86: remove `-3dnow{,a}` from target features
  kbuild: rust-analyzer: mark `rust_is_available.sh` invocation as recursive
  rust: add intrinsics to fix `-Os` builds
  kbuild: rust: skip -fmin-function-alignment in bindgen flags
  rust: Support latest version of `rust-analyzer`
  rust: macros: indent list item in `module!`'s docs
  rust: fix the default format for CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT
  rust: suppress error messages from CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT

rust: add intrinsics to fix `-Os` builds

2024-08-09T22:05:10+00:00

Alice reported [1] that an arm64 build failed with:

    ld.lld: error: undefined symbol: __extendsfdf2
    >>> referenced by core.a6f5fc5794e7b7b3-cgu.0
    >>>               rust/core.o:(::midpoint) in archive vmlinux.a
    >>> referenced by core.a6f5fc5794e7b7b3-cgu.0
    >>>               rust/core.o:(::midpoint) in archive vmlinux.a

    ld.lld: error: undefined symbol: __truncdfsf2
    >>> referenced by core.a6f5fc5794e7b7b3-cgu.0
    >>>               rust/core.o:(::midpoint) in archive vmlinux.a

Rust 1.80.0 or later together with `CONFIG_CC_OPTIMIZE_FOR_SIZE=y`
is what triggers it.

In addition, x86_64 builds also fail the same way.

Similarly, compiling with Rust 1.82.0 (currently in nightly) makes
another one appear, possibly due to the LLVM 19 upgrade there:

    ld.lld: error: undefined symbol: __eqdf2
    >>> referenced by core.20495ea57a9f069d-cgu.0
    >>>               rust/core.o:(::next_up) in archive vmlinux.a
    >>> referenced by core.20495ea57a9f069d-cgu.0
    >>>               rust/core.o:(::next_down) in archive vmlinux.a

Gary adds [1]:

> Usually the fix on rustc side is to mark those functions as `#[inline]`
>
> All of {midpoint,next_up,next_down} are indeed unstable functions not
> marked as inline...

Fix all those by adding those intrinsics to our usual workaround.

[ Trevor quickly submitted a fix to upstream Rust [2] that has already
  been merged, to be released in Rust 1.82.0 (2024-10-17). - Miguel ]

Cc: Gary Guo 
Reported-by: Alice Ryhl 
Closes: https://rust-for-linux.zulipchat.com/#narrow/stream/x/topic/x/near/455637364 [1]
Reviewed-by: Trevor Gross 
Tested-by: Alice Ryhl 
Tested-by: Boqun Feng 
Reviewed-by: Gary Guo 
Link: https://github.com/rust-lang/rust/pull/128749 [2]
Link: https://lore.kernel.org/r/20240806150619.192882-1-ojeda@kernel.org
[ Shortened Zulip link. - Miguel ]
Signed-off-by: Miguel Ojeda

kbuild: rust: skip -fmin-function-alignment in bindgen flags

2024-08-09T22:01:01+00:00

GCC 14 recently added -fmin-function-alignment option and the
root Makefile uses it to replace -falign-functions when available.
However, this flag can cause issues when passed to the Rust
Makefile and affect the bindgen process. Bindgen relies on
libclang to parse C code, and currently does not support the
-fmin-function-alignment flag, leading to compilation failures
when GCC 14 is used.

This patch addresses the issue by adding -fmin-function-alignment
to the bindgen_skip_c_flags in rust/Makefile. This prevents the
flag from causing compilation issues.

[ Matthew and Gary confirm function alignment should not change
  the ABI in a way that bindgen would care about, thus we did
  not need the extra logic for bindgen from v2. - Miguel ]

Link: https://lore.kernel.org/linux-kbuild/20240222133500.16991-1-petr.pavlu@suse.com/
Signed-off-by: Zehui Xu 
Reviewed-by: Alice Ryhl 
Reviewed-by: Neal Gompa 
Reviewed-by: Gary Guo 
Link: https://lore.kernel.org/r/20240731134346.10630-1-zehuixu@whu.edu.cn
[ Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: Support latest version of `rust-analyzer`

2024-08-06T23:16:52+00:00

Sets the `sysroot` field in rust-project.json which is now needed in
newer versions of rust-analyzer instead of the `sysroot_src` field.

Till [1] `rust-analyzer` used to guess the `sysroot` based on the
`sysroot_src` at [2]. Now `sysroot` is a required parameter for a
`rust-project.json` file. It is required because `rust-analyzer`
need it to find the proc-macro server [3].

In the current version of `rust-analyzer` the `sysroot_src` is only used
to include the inbuilt library crates (std, core, alloc, etc) [4]. Since
we already specify the core library to be included in the
`rust-project.json` we don't need to define the `sysroot_src`.

Code editors like VS Code try to use the latest version of rust-analyzer
(which is updated every week) instead of the version of rust-analyzer
that comes with the rustup toolchain (which is updated every six weeks
along with the rust version).

Without this change `rust-analyzer` is breaking for anyone using VS Code.
As they are getting the latest version of `rust-analyzer` with the
changes made in [1].

`rust-analyzer` will also start breaking for other developers as they
update their rust version (assuming that also updates the rust-analyzer
version on their system).

This patch should work with every setup as there is no more guess work
being done by `rust-analyzer`.

[ Lukas, who leads the rust-analyzer team, says:

`sysroot_src` is required now if you want to have the sysroot
source libraries be loaded. I think we used to infer it as
`{sysroot}/lib/rustlib/src/rust/library` before when only the
`sysroot` field was given but that was since changed to make it
possible in having a sysroot without the standard library sources
(that is only have the binaries available). So if you want the
library sources to be loaded by rust-analyzer you will have to set
that field as well now.

- Miguel ]

Link: https://github.com/rust-lang/rust-analyzer/pull/17287 [1]
Link: https://github.com/rust-lang/rust-analyzer/blob/f372a8a1176ff8dd5f45ab2ddd45f3530db0374f/crates/project-model/src/workspace.rs#L367-L374 [2]
Link: https://github.com/rust-lang/rust-analyzer/blob/eeb192b79aeac47b40add66347022af17a74fbaf/crates/project-model/src/sysroot.rs#L180-L192 [3]
Link: https://github.com/search?q=repo%3AVeykril%2Frust-analyzer%20src_root()&type=code [4]
Tested-by: Dirk Behme
Signed-off-by: Sarthak Singh
Link: https://rust-for-linux.zulipchat.com/#narrow/stream/291565-Help/topic/How.20to.20rust-analyzer.20correctly.20working
Link: https://lore.kernel.org/r/20240724172713.899399-1-sarthak.singh99@gmail.com
[ Formatted comment, fixed typo and removed spurious empty line. - Miguel ]
Signed-off-by: Miguel Ojeda

rust: firmware: fix invalid rustdoc link

2024-07-31T11:24:29+00:00

remove an extra quote from the doc comment so that rustdoc
no longer genertes a link to a nonexistent file.

Signed-off-by: Andrew Ballance 
Reviewed-by: Danilo Krummrich 
Acked-by: Miguel Ojeda 
Fixes: de6582833db0 ("rust: add firmware abstractions")
Link: https://lore.kernel.org/r/20240709004426.44854-1-andrewjballance@gmail.com
Signed-off-by: Greg Kroah-Hartman