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Fri, 26 Dec 2025 11:15:12 -0800 (PST) Date: Fri, 26 Dec 2025 19:15:10 +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=H4sIAL3eTmkC/1WMQQ6CMBBFr0JmbU1nhCKuvIdxAe0ATZSSljQSw t0tuJHl+z/vLRDYWw5wyxbwHG2wbkhwOWWg+3roWFiTGEhSgZIqURsjeJi8G2fRFiUjccOIEpI xem7tZ689nol7Gybn5z0ecVt/HUI6dCIKFFzK2mCjK62Ke+dc9+Kzdm/YQpH+ZXWUKcm5uSrVp jcv84O8rusXmBtqBuQAAAA= 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=1766776511; l=2293; i=mmaurer@google.com; s=20250429; h=from:subject:message-id; bh=ldHNZ5zeLjLocyFIc9O/h8jKxqQSgOapyv1qPGU77Fo=; b=G/xqDZrLBAz7oFDv0/3ZcSk+1lnR0jJc6L02D0JBb3w2OKY1pEZt/hzMZlgw+mJvMIgrSZItz r59z+d7bLBED3w3+R6UoEayU1BEtV9UUNuuBLQzc4u3s2tBWdWDPCKM X-Mailer: b4 0.14.2 Message-ID: <20251226-add-entropy-v3-1-a3440823a07d@google.com> Subject: [PATCH v3] 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 Reviewed-by: Alexandre Courbot Reviewed-by: Alice Ryhl --- Changes in v3: - Fixed doclink to be srctree-based instead of relative. - Switched to prelude import instead of fine-grained imports. - Link to v2: https://lore.kernel.org/r/20251216-add-entropy-v2-1-4d866f251= 474@google.com 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 | 18 ++++++++++++++++++ 2 files changed, 19 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..3e0aef2f53af122f510b34c4743= a20452aaad9ad --- /dev/null +++ b/rust/kernel/rand.rs @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Randomness. +//! +//! C header: [`include/linux/random.h`](srctree/include/linux/random.h) + +use crate::prelude::*; + +/// 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