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Mon, 15 Dec 2025 16:37:17 -0800 (PST) Date: Tue, 16 Dec 2025 00:37:15 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIALqpQGkC/1XMQQrDIBCF4auEWdfiDNiQrnqPkoXRiRFaDRokI eTutemqy//B+3bInDxnuDc7JC4++xhq0KUBM+ngWHhbG0iSQkmd0NYKDkuK8yZG1TISD4wooT7 mxKNfT+3Z1558XmLaTrzgd/05hPTnFBQouJXa4mA6c1MPF6N78dXEN/THcXwAsB19bKcAAAA= X-Change-Id: 20251029-add-entropy-f57e12ebe110 X-Developer-Key: i=mmaurer@google.com; a=ed25519; pk=2Ezhl7+fEjTOMVFpplDeak2AdQ8cjJieLRVJdNzrW+E= X-Developer-Signature: v=1; a=ed25519-sha256; t=1765845435; l=2092; i=mmaurer@google.com; s=20250429; h=from:subject:message-id; bh=Mqk5zIfaBDUtjJZOyrmGT/+i2AR6QM1tSX71Qn4f8K0=; b=omxI4bkkK/AfpKhEqESb44yKwWRrfbaH02BLbNp42DipDEfvzhAop6wRYSBNOiKc3L1OreKu4 rjNIMVlyRCbAzB7xGN4CqB1gffKkiOQNIe3lNjXXoc8X3RFsvoo4uho X-Mailer: b4 0.14.2 Message-ID: <20251216-add-entropy-v2-1-4d866f251474@google.com> Subject: [PATCH v2] rust: Add support for feeding entropy to randomness pool From: Matthew Maurer To: Miguel Ojeda , Boqun Feng , Gary Guo , "=?utf-8?q?Bj=C3=B6rn_Roy_Baron?=" , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Matthew Maurer Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Adds just enough support to allow device drivers to feed entropy to the central pool. Signed-off-by: Matthew Maurer --- Changes in v2: - Added more details in the docs about the API, specifically about it not crediting entropy and when it ought to be used. - Link to v1: https://lore.kernel.org/r/20251212-add-entropy-v1-1-e70ad1bc9= c65@google.com --- rust/kernel/lib.rs | 1 + rust/kernel/rand.rs | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index f812cf12004286962985a068665443dc22c389a2..bf64752d276b0bdea06ac0de8a5= e219190129377 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -130,6 +130,7 @@ pub mod ptr; #[cfg(CONFIG_RUST_PWM_ABSTRACTIONS)] pub mod pwm; +pub mod rand; pub mod rbtree; pub mod regulator; pub mod revocable; diff --git a/rust/kernel/rand.rs b/rust/kernel/rand.rs new file mode 100644 index 0000000000000000000000000000000000000000..abaafa12c6ec7fe600463dfc2bd= b78385a09cc52 --- /dev/null +++ b/rust/kernel/rand.rs @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Randomness. +//! +//! C header: [`include/linux/random.h`](../../../../include/linux/random.= h) + +use crate::bindings; +use crate::ffi::c_void; + +/// Adds the given buffer to the entropy pool, but does not credit any ent= ropy. +/// +/// This is intended for use mixing in data that is likely to differ betwe= en devices or boots, but +/// may otherwise be predictable. Examples include MAC addresses or RTC va= lues. This slightly +/// improves randomness in entropy-constrained environments (especially co= mmon for embedded +/// devices). +pub fn add_device_randomness(buf: &[u8]) { + // SAFETY: We just need the pointer to be valid for the length, which = a slice provides. + unsafe { bindings::add_device_randomness(buf.as_ptr().cast::()= , buf.len()) }; +} --- base-commit: 008d3547aae5bc86fac3eda317489169c3fda112 change-id: 20251029-add-entropy-f57e12ebe110 Best regards, --=20 Matthew Maurer