rust: adapt `alloc` crate to the kernel

This customizes the subset of the Rust standard library `alloc` that
was just imported as-is, mainly by:

- Adding SPDX license identifiers.

- Skipping m

rust: adapt `alloc` crate to the kernel

This customizes the subset of the Rust standard library `alloc` that
was just imported as-is, mainly by:

- Adding SPDX license identifiers.

- Skipping modules (e.g. `rc` and `sync`) via new `cfg`s.

- Adding fallible (`try_*`) versions of existing infallible methods
(i.e. returning a `Result` instead of panicking).

Since the standard library requires stable/unstable attributes,
these additions are annotated with:

#[stable(feature = "kernel", since = "1.0.0")]

Using "kernel" as the feature allows to have the additions
clearly marked. The "1.0.0" version is just a placeholder.

(At the moment, only one is needed, but in the future more
fallible methods will be added).

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Gary Guo <gary@garyguo.net>
Co-developed-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Matthew Bakhtiari <dev@mtbk.me>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

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rust: import upstream `alloc` crate

This is a subset of the Rust standard library `alloc` crate,
version 1.62.0, licensed under "Apache-2.0 OR MIT", from:

https://github.com/rust-lang/rust/tree

rust: import upstream `alloc` crate

This is a subset of the Rust standard library `alloc` crate,
version 1.62.0, licensed under "Apache-2.0 OR MIT", from:

https://github.com/rust-lang/rust/tree/1.62.0/library/alloc/src

The files are copied as-is, with no modifications whatsoever
(not even adding the SPDX identifiers).

For copyright details, please see:

https://github.com/rust-lang/rust/blob/1.62.0/COPYRIGHT

The next patch modifies these files as needed for use within
the kernel. This patch split allows reviewers to double-check
the import and to clearly see the differences introduced.

Vendoring `alloc`, at least for the moment, allows us to have fallible
allocations support (i.e. the `try_*` versions of methods which return
a `Result` instead of panicking) early on. It also gives a bit more
freedom to experiment with new interfaces and to iterate quickly.

Eventually, the goal is to have everything the kernel needs in
upstream `alloc` and drop it from the kernel tree.

For a summary of work on `alloc` happening upstream, please see:

https://github.com/Rust-for-Linux/linux/issues/408

The following script may be used to verify the contents:

for path in $(cd rust/alloc/ && find . -type f -name '*.rs'); do
curl --silent --show-error --location \
https://github.com/rust-lang/rust/raw/1.62.0/library/alloc/src/$path \
| diff --unified rust/alloc/$path - && echo $path: OK
done

Reviewed-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

show more ...