This expands the existing smp barriers to also mandatory barriers and DMA
barriers.
The API looks like: `mb(Ordering)`/`smp_mb(Ordering)`/`dma_mb(Ordering)`,
where `Ordering` is one of `Full`, `Read`, `Write`.
I retain the use of generics to avoid duplicating `CONFIG_SMP` check (but
also retaining the ability to easily add `Acquire` and `Release` ordering
in the future).
A user of these introduced API is included in patch 3, which is a
concurrency bug that exists in Nova code today due to missing barriers.
Signed-off-by: Gary Guo <gary@garyguo.net>
---
Changes in v2:
- Dropped `Acquire` and `Release` aliases of `Full` (Joel)
- Use macros to implement most `MemoryBarrier`
- Split Nova change to GSP->CPU commit and CPU->GSP commit (Joel)
- Link to v1: https://patch.msgid.link/20260402152443.1059634-2-gary@kernel.org
To: Miguel Ojeda <ojeda@kernel.org>
To: Boqun Feng <boqun@kernel.org>
To: Gary Guo <gary@garyguo.net>
To: Björn Roy Baron <bjorn3_gh@protonmail.com>
To: Benno Lossin <lossin@kernel.org>
To: Andreas Hindborg <a.hindborg@kernel.org>
To: Alice Ryhl <aliceryhl@google.com>
To: Trevor Gross <tmgross@umich.edu>
To: Danilo Krummrich <dakr@kernel.org>
To: Will Deacon <will@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
To: Mark Rutland <mark.rutland@arm.com>
To: Alexandre Courbot <acourbot@nvidia.com>
To: David Airlie <airlied@gmail.com>
To: Simona Vetter <simona@ffwll.ch>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Akira Yokosawa <akiyks@gmail.com>
Cc: Daniel Lustig <dlustig@nvidia.com>
Cc: Joel Fernandes <joelagnelf@nvidia.com>
Cc: rust-for-linux@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: nova-gpu@lists.linux.dev
Cc: dri-devel@lists.freedesktop.org
Cc: lkmm@lists.linux.dev
---
Gary Guo (4):
rust: sync: add helpers for mb, dma_mb and friends
rust: sync: generic memory barriers
gpu: nova-core: fix barrier usage in CPU->GSP messaging path
gpu: nova-core: fix barrier usage in GSP->CPU messaging path
drivers/gpu/nova-core/gsp/cmdq.rs | 18 ++++++
drivers/gpu/nova-core/gsp/fw.rs | 12 ----
rust/helpers/barrier.c | 30 +++++++++
rust/kernel/sync/atomic/ordering.rs | 2 +-
rust/kernel/sync/barrier.rs | 123 ++++++++++++++++++++++++++++--------
5 files changed, 144 insertions(+), 41 deletions(-)
---
base-commit: a87737435cfa134f9cdcc696ba3080759d04cf72
change-id: 20260609-rust-barrier-63078ea76216
Best regards,
--
Gary Guo <gary@garyguo.net>