Adds a wrapper around `kuid_t` called `Kuid`. This allows us to define
various operations on kuids such as equality and current_euid. It also
lets us provide conversions from kuid into userspace values.
Rust Binder needs these operations because it needs to compare kuids for
equality, and it needs to tell userspace about the pid and uid of
incoming transactions.
To read kuids from a `struct task_struct`, you must currently use
various #defines that perform the appropriate field access under an RCU
read lock. Currently, we do not have a Rust wrapper for rcu_read_lock,
which means that for this patch, there are two ways forward:
1. Inline the methods into Rust code, and use __rcu_read_lock directly
rather than the rcu_read_lock wrapper. This gives up lockdep for
these usages of RCU.
2. Wrap the various #defines in helpers and call the helpers from Rust.
This patch uses the second option. One possible disadvantage of the
second option is the possible introduction of speculation gadgets, but
as discussed in [1], the risk appears to be acceptable.
Of course, once a wrapper for rcu_read_lock is available, it is
preferable to use that over either of the two above approaches.
Link: https://lore.kernel.org/all/202312080947.674CD2DC7@keescook/ [1]
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240915-alice-file-v10-7-88484f7a3dcf@google.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Rust's `unused_imports` lint covers both unused and redundant imports.
In the upcoming 1.78.0, the lint detects more cases of redundant imports
[1], e.g.:
error: the item `bindings` is imported redundantly
--> rust/kernel/print.rs:38:9
|
38 | use crate::bindings;
| ^^^^^^^^^^^^^^^ the item `bindings` is already defined by prelude
Most cases are `use crate::bindings`, plus a few other items like `Box`.
Thus clean them up.
Note that, in the `bindings` case, the message "defined by prelude"
above means the extern prelude, i.e. the `--extern` flags we pass.
Link: https://github.com/rust-lang/rust/pull/117772 [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240401212303.537355-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Replace instances of 'ref-count[ed]' with 'refcount[ed]' to increase
consistency within the Rust documentation. The latter form is used more
widely in the rest of the kernel:
```console
$ rg '(\*|//).*?\srefcount(|ed)[\s,.]' | wc -l
1605
$ rg '(\*|//).*?\sref-count(|ed)[\s,.]' | wc -l
43
```
(numbers are for commit 052d534373 ("Merge tag 'exfat-for-6.8-rc1'
of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat"))
Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240131-doc-fixes-v3-v3-7-0c8af94ed7de@valentinobst.de
[ Reworded to use the kernel's commit description style. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Reduce the chances of compilation failures due to integer type
mismatches in `CondVar`.
When an integer is defined using a #define in C, bindgen doesn't know
which integer type it is supposed to be, so it will just use `u32` by
default (if it fits in an u32). Whenever the right type is something
else, we insert a cast in Rust. However, this means that the code has a
lot of extra casts, and sometimes the code will be missing casts if u32
happens to be correct on the developer's machine, even though the type
might be something else on a different platform.
This patch updates all uses of such constants in
`rust/kernel/sync/condvar.rs` to use constants defined with the right
type. This allows us to remove various unnecessary casts, while also
future-proofing for the case where `unsigned int != u32` (even though
that is unlikely to ever happen in the kernel).
I wrote this patch at the suggestion of Benno in [1].
Link: https://lore.kernel.org/all/nAEg-6vbtX72ZY3oirDhrSEf06TBWmMiTt73EklMzEAzN4FD4mF3TPEyAOxBZgZtjzoiaBYtYr3s8sa9wp1uYH9vEWRf2M-Lf4I0BY9rAgk=@proton.me/ [1]
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Tiago Lam <tiagolam@gmail.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240108-rb-new-condvar-methods-v4-4-88e0c871cc05@google.com
[ Added note on the unlikeliness of `sizeof(int)` changing. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Sleep on a condition variable with a timeout.
This is used by Rust Binder for process freezing. There, we want to
sleep until the freeze operation completes, but we want to be able to
abort the process freezing if it doesn't complete within some timeout.
Note that it is not enough to avoid jiffies by introducing a variant of
`CondVar::wait_timeout` that takes the timeout in msecs because we need
to be able to restart the sleep with the remaining sleep duration if it
is interrupted, and if the API takes msecs rather than jiffies, then
that would require a conversion roundtrip jiffies->msecs->jiffies that
is best avoided.
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Tiago Lam <tiagolam@gmail.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240108-rb-new-condvar-methods-v4-3-88e0c871cc05@google.com
[ Added `CondVarTimeoutResult` re-export and fixed typo. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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>
