[PATCH v6 0/9] LKMM generic atomics in Rust

Boqun Feng
2025-07-10T06:00:59Z

Hi all,

This is the v6 of LKMM atomics in Rust, you can find the previous
versions at:

v5: https://lore.kernel.org/rust-for-linux/20250618164934.19817-1-boqun.feng@gmail.com/
v4: https://lore.kernel.org/rust-for-linux/20250609224615.27061-1-boqun.feng@gmail.com/
v3: https://lore.kernel.org/rust-for-linux/20250421164221.1121805-1-boqun.feng@gmail.com/
v2: https://lore.kernel.org/rust-for-linux/20241101060237.1185533-1-boqun.feng@gmail.com/
v1: https://lore.kernel.org/rust-for-linux/20240612223025.1158537-1-boqun.feng@gmail.com/
wip: https://lore.kernel.org/rust-for-linux/20240322233838.868874-1-boqun.feng@gmail.com/

I dropped the support for atomic pointers for now
(Atomic<{isize,usize}> still exists), because further more work is
needed to ensure the implementation could preserve provenance [1]. And
we already other series depending on atomics [2], so it makes sense to
get some basic support in-tree.

Peter & Ingo, I take it that it's OK for me to send a PR to tip later
this week or early next week if things went well? Of course, any
feedback is welcome!

Changes since v5:

* Replace `as` cast with `ptr.cast()` in atomic/ops.rs per the
suggestion of Andreas.
* Explicitly document `Acquire` and `Release` ordering definition per
the suggestion of Peter.
* Rename `All` to `Any` for ordering accept traits per the suggestion of
Andreas.
* Remove unnecessary fields in `AcquireOrRelaxed` and `ReleaseOrRelaxed`
per the suggestion of Gary.
* Add round-trip transmutability (thanks Benno) as the safety
requirement of `AllowAtomic` per discussion with Gary and Benno.
* Add doc alias for xchg() and cmpxchg() per the suggestion of Benno.
* Examples and documentation improvement.
* Applied Reviewed-by tags from Alice and Andreas.

[1]: https://lore.kernel.org/rust-for-linux/aGg4sIORQiG02IoD@Mac.home/
[2]: https://lore.kernel.org/rust-for-linux/20250709-module-params-v3-v16-1-4f926bcccb50@kernel.org/

Regards,
Boqun

Boqun Feng (9):
rust: Introduce atomic API helpers
rust: sync: Add basic atomic operation mapping framework
rust: sync: atomic: Add ordering annotation types
rust: sync: atomic: Add generic atomics
rust: sync: atomic: Add atomic {cmp,}xchg operations
rust: sync: atomic: Add the framework of arithmetic operations
rust: sync: atomic: Add Atomic<u{32,64}>
rust: sync: Add memory barriers
rust: sync: atomic: Add Atomic<{usize,isize}>

MAINTAINERS | 4 +-
rust/helpers/atomic.c | 1040 +++++++++++++++++++++
rust/helpers/barrier.c | 18 +
rust/helpers/helpers.c | 2 +
rust/kernel/sync.rs | 2 +
rust/kernel/sync/atomic.rs | 193 ++++
rust/kernel/sync/atomic/generic.rs | 567 +++++++++++
rust/kernel/sync/atomic/ops.rs | 195 ++++
rust/kernel/sync/atomic/ordering.rs | 97 ++
rust/kernel/sync/barrier.rs | 65 ++
scripts/atomic/gen-atomics.sh | 1 +
scripts/atomic/gen-rust-atomic-helpers.sh | 67 ++
12 files changed, 2250 insertions(+), 1 deletion(-)
create mode 100644 rust/helpers/atomic.c
create mode 100644 rust/helpers/barrier.c
create mode 100644 rust/kernel/sync/atomic.rs
create mode 100644 rust/kernel/sync/atomic/generic.rs
create mode 100644 rust/kernel/sync/atomic/ops.rs
create mode 100644 rust/kernel/sync/atomic/ordering.rs
create mode 100644 rust/kernel/sync/barrier.rs
create mode 100755 scripts/atomic/gen-rust-atomic-helpers.sh

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