From nobody Sat Feb 7 19:04:12 2026 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81F2219E819 for ; Tue, 30 Dec 2025 17:53:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767117241; cv=none; b=F735D2gpsL5EqSygK/M1D7jsCJ9aYp4fcb8ricf9xjIgWtkiBnFMoTTrf6JxkwuKDSNIlBnPW2t2sKL8KZWg4D5JsMs6VAZemctOEbBzrqzywlUxUZS0gr54t4Ow+uvSW+/ReR70ocxnTS2xk3BUChvjKFba6FI6kxtpaABJflM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767117241; c=relaxed/simple; bh=JBh+MFnoGyYCeEvR8aZhFlDltAqOMVVaHmWlhKuZav4=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=K9PO9jZibaDnRoKhrf4MGeZGOKFyShjllrR9cGgZpUngvvGwEVxNTELZLXCNQrNfRixfLV/bO2gL23qiZkZj+V1dvcT2oitntnn6gXgkip/Hw0Kn2YfpZDTbqMKfi+kKj4rnmCALQnFmySBAVRgRRkZ4kg/VhpfOQBBHaywFLqI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--mmaurer.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=nalapQQp; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--mmaurer.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="nalapQQp" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-34ab8693a2cso28410155a91.0 for ; Tue, 30 Dec 2025 09:53:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1767117239; x=1767722039; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=far2F8SCiAeYEaUvenEigD/H34t42x7S+P8As/u5ias=; b=nalapQQpMMFKxjxlaTejRUVAViVtmjNea9JXh/A1B1sqOrLlJ50PrWw9zB+69njybo s4YWnTZqk7iEvJDtw8dio8chQYI41E4JYBMiOAkiUGIp9HaYFglJmNl+mKNUZVzTvdjr DaxIoo6mFl7tkqRnCX03EygXLbBWWwMCV/4mUIZSXbPaPLc20+k5wg3GCOVtl/9hAdpa YnXON15fwSj8Og1Ae1rNaHQK9Z/YSV7tFTX/pY8KSvnUeKBj489AM5GeipX1+rht11yb 3+5+Ze7dpBAcUJembHXN4mHnV4n/1pbM1d/yp+bfG4WkoVrkW+vqZrHT9eLeXWCbSwM6 fN3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767117239; x=1767722039; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=far2F8SCiAeYEaUvenEigD/H34t42x7S+P8As/u5ias=; b=bS42jSs6Irtpchgxp1Wng5h51oi/QLUyq3mniyHaHsjSdGwHHHRfUjpm/j4CXpOiF0 V1HRHyslX0vWu/nmLccvfP6hUGLmEJleCGoRD+Ctio9MlUx2Vq1O8ELtxGx4L2d5JrLG fzNCPDXsCP7EzMA6sUpCkzDYSVqDMywUNhVTdHBI+SP1Mke2DLn6hSdqHx2mcLN5CPl2 6m4xDMTVixgcpg5TICnyqvBbqOOlkqIxUrQgDmDuvdcs6ERvIqMOut93UmzG5QlmfVmE AcZ94jl6dqBov89pmN0x7XcBOgx8gDRPwMed1fCpi22WNhEHIMe3x6WBYVHL6kqvPIwF nWEw== X-Gm-Message-State: AOJu0YwgIu4LGIh5EXvIkr6wkS3ooAtfGnWvcFoxIze1zXKQgyotZpbm QO1HQMqx56ybu8UTvHKEFrHrMrxamNY2FEyAk6mMUNFm80y3n/WZvqUBV7wv8IH2mIRKy4E2jJV qgtlktuwPCw== X-Google-Smtp-Source: AGHT+IHV2kdC1JaYTIJG6O6YnJRAt6P0XRekxsdSb1kCm56XaC/gulRACcgSKgWwuMs3jAxCLVN4rnMYZfz9 X-Received: from dlbeg11.prod.google.com ([2002:a05:7022:f8b:b0:121:766b:11e4]) (user=mmaurer job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:150d:b0:11b:9386:7ecd with SMTP id a92af1059eb24-121722fa7c2mr31544819c88.42.1767117238799; Tue, 30 Dec 2025 09:53:58 -0800 (PST) Date: Tue, 30 Dec 2025 17:53:57 +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=H4sIALQRVGkC/2XMQQ6CMBCF4auQrq3pTAtFV97DuCh0gCZKSSFEQ ri7BTegyzeT759ZT8FRz67JzAKNrne+jUOdElY2pq2JOxs3Q4EpCLxwYy2ndgi+m3iVagKkggA Ei6ILVLn3Vrs/4m5cP/gwbfER1uu3g4CHzggcOGlhLBTlpczSW+19/aRz6V9sDY24x9kRY8TK5 llWxa/S6g/LHcYfLCM2UimRozRC2wNeluUDuUfrJiEBAAA= 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=1767117237; l=2619; i=mmaurer@google.com; s=20250429; h=from:subject:message-id; bh=JBh+MFnoGyYCeEvR8aZhFlDltAqOMVVaHmWlhKuZav4=; b=hTahNGSIZWN5fMIGiiwqZSArhmkOx8lNQCkXNCp8GTeHbpi99H7N8MNHbgNqJMjgw6zAw4d4a fUyMmJ8Rl9vCW6Hq1cH/gKB4RA4IMyE3zB/0OdXJl85Uv/roQKYgIFV X-Mailer: b4 0.14.2 Message-ID: <20251230-add-entropy-v4-1-fa9485b6d372@google.com> Subject: [PATCH v4] 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, Alexandre Courbot , 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. Reviewed-by: Alice Ryhl Reviewed-by: Alexandre Courbot Signed-off-by: Matthew Maurer --- Changes in v4: - Adjusted documentation phrasing. - Renamed module from `rand` to `random` to be more in line with the header name. - Link to v3: https://lore.kernel.org/r/20251226-add-entropy-v3-1-a3440823a= 07d@google.com 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/random.rs | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index f812cf12004286962985a068665443dc22c389a2..c82e6747043e2472d6b5e4d9043= fa8bc6d3c8434 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 random; pub mod rbtree; pub mod regulator; pub mod revocable; diff --git a/rust/kernel/random.rs b/rust/kernel/random.rs new file mode 100644 index 0000000000000000000000000000000000000000..a9b19698e09665696fef77b4486= c4a1a20d0a42e --- /dev/null +++ b/rust/kernel/random.rs @@ -0,0 +1,17 @@ +// 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 function mixes in data that is likely to differ between devices o= r boots, but may +/// otherwise be predictable. Examples include MAC addresses or RTC values= . This slightly improves +/// randomness in entropy-constrained environments (especially common 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