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Wed, 31 Dec 2025 04:22:36 -0800 (PST) Date: Wed, 31 Dec 2025 12:22:24 +0000 Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAIAVVWkC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyDHUUlJIzE vPSU3UzU4B8JSMDI1NDI2MD3aLy/LzkVF3DVIsUo9RUg6TkNEsloOKCotS0zAqwQdGxtbUAFXT clFgAAAA= X-Change-Id: 20251230-rwonce-1e8d2ee0bcf9 X-Developer-Key: i=aliceryhl@google.com; a=openpgp; fpr=49F6C1FAA74960F43A5B86A1EE7A392FDE96209F X-Developer-Signature: v=1; a=openpgp-sha256; l=1686; i=aliceryhl@google.com; h=from:subject:message-id; bh=DgkCDNZwcq8gq47PvBSES/tVZ/480I2oLP6adymLeb4=; b=owEBbQKS/ZANAwAKAQRYvu5YxjlGAcsmYgBpVRWGF5bAiUtejlxi6BOwMVDKnGMRxV0brpJMZ 4N76blF6DqJAjMEAAEKAB0WIQSDkqKUTWQHCvFIvbIEWL7uWMY5RgUCaVUVhgAKCRAEWL7uWMY5 Rq6PEACahBDOuqhWNRdS7KKKt5/h9IB0Ae0tEIYhZCaGdynMz9p5ZroHJGY3427iEbwD1Xf1sd3 krvr6Thhw3P3Xe/n9H8Zv/X9u1c5luZ3Xf4eCUMRH4chFWH9JwzEvBz7jXADexXhLdQpug7K2mb wcyPQj1ud8v+7Di8+fu4PtJLHimoywoMf6ZFhCGnAxPySJWvVweGV7hUrW8LxDszplrE2HZ8tD9 RPAbn1uqanDGL40aeAib7oCMvMY0u3Qwpf7JB+7YpeulCoPXBOoLck6sczMbHd7yzidbpiP+RnS 37uYnZopCUQmCd47pDgFlfMgZD27v6IYXqZ8zIryrOl3Sod72AtB9UoCLEW11pV2LQ1AlYpBJL3 rU7Ya3QisvjzdEQ6OOLsnzwTh0b25pX6GjpAOkQxz6xI3oeH9Epbm5H/pviAgf3R1wjJrOvIOxj 0GmRhz2x4wq8lHjcbjoljHHRYDgHFXMm0qSjahun8/DqZkoYlfBxzuxT46T2n5gdefNJ8ejq+Dv Sm69I+Q/czN4RKBQIQDvayvG7VhtPNqrAKgOupQ9wDPuDSMURnwra3sFVkMWxmkk6wr8VB86lin 9RO+10zQWOISHeiZ3OkAmQ5U361UXsQx2g45A72GjESpW/kXTosPejSa7Qj5uclYBBvCaLrP0Uj f+YHVZGzb5+fZ7Q== X-Mailer: b4 0.14.2 Message-ID: <20251231-rwonce-v1-0-702a10b85278@google.com> Subject: [PATCH 0/5] Add READ_ONCE and WRITE_ONCE to Rust From: Alice Ryhl To: Boqun Feng , Will Deacon , Peter Zijlstra Cc: Richard Henderson , Matt Turner , Magnus Lindholm , Catalin Marinas , Miguel Ojeda , Gary Guo , "=?utf-8?q?Bj=C3=B6rn_Roy_Baron?=" , Benno Lossin , Andreas Hindborg , Trevor Gross , Danilo Krummrich , Mark Rutland , FUJITA Tomonori , Frederic Weisbecker , Lyude Paul , Thomas Gleixner , Anna-Maria Behnsen , John Stultz , Stephen Boyd , Alexander Viro , Christian Brauner , Jan Kara , linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, rust-for-linux@vger.kernel.org, linux-fsdevel@vger.kernel.org, Alice Ryhl Content-Type: text/plain; charset="utf-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251231_042239_497226_B88E1F96 X-CRM114-Status: GOOD ( 11.91 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org There are currently a few places in the kernel where we use volatile reads when we really should be using `READ_ONCE`. To make it possible to replace these with proper `READ_ONCE` calls, introduce a Rust version of `READ_ONCE`. A new config option CONFIG_ARCH_USE_CUSTOM_READ_ONCE is introduced so that Rust is able to use conditional compilation to implement READ_ONCE in terms of either a volatile read, or by calling into a C helper function, depending on the architecture. This series is intended to be merged through ATOMIC INFRASTRUCTURE. Signed-off-by: Alice Ryhl --- Alice Ryhl (5): arch: add CONFIG_ARCH_USE_CUSTOM_READ_ONCE for arm64/alpha rust: sync: add READ_ONCE and WRITE_ONCE rust: sync: support using bool with READ_ONCE rust: hrtimer: use READ_ONCE instead of read_volatile rust: fs: use READ_ONCE instead of read_volatile MAINTAINERS | 2 + arch/Kconfig | 11 +++ arch/alpha/Kconfig | 1 + arch/alpha/include/asm/rwonce.h | 4 +- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/rwonce.h | 4 +- rust/helpers/helpers.c | 1 + rust/helpers/rwonce.c | 34 +++++++ rust/kernel/fs/file.rs | 8 +- rust/kernel/sync.rs | 2 + rust/kernel/sync/rwonce.rs | 207 ++++++++++++++++++++++++++++++++++++++++ rust/kernel/time/hrtimer.rs | 8 +- 12 files changed, 268 insertions(+), 15 deletions(-) --- base-commit: f8f9c1f4d0c7a64600e2ca312dec824a0bc2f1da change-id: 20251230-rwonce-1e8d2ee0bcf9 Best regards, -- Alice Ryhl