From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FC50EB64DA for ; Sat, 24 Jun 2023 09:25:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233033AbjFXJZ0 (ORCPT ); Sat, 24 Jun 2023 05:25:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231752AbjFXJZX (ORCPT ); Sat, 24 Jun 2023 05:25:23 -0400 Received: from mail-4316.protonmail.ch (mail-4316.protonmail.ch [185.70.43.16]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B347B1BF2; Sat, 24 Jun 2023 02:25:18 -0700 (PDT) Date: Sat, 24 Jun 2023 09:25:03 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1687598716; x=1687857916; bh=8VcczR7TSrM7NM+PW6yKJnJo9tNhZ0vALWp60pbLLGg=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=CQ8JgzRY5eg8ZFcZ8U/kQhsNREbJ5BKQRnOYiPvVf/nAkIyKAYf6M0555lN4BsGux BgbRBJRRq6SPFVx3OK1+8IOj8efQfXqs7HoBvUSAjSsMsXf+amhcMnj7ZZmwHT1SCW dw9NwCnI3mIOpdzgtoInHRNvvfVFCSrW9lkgSGG15BWohm61FZ0I9gy/wjXnPiXODD ceMgI69ITB2prVNu2aW4W5EaPhoVI7OzGIp0JPResWODeinoRFa2W4ydfKxbShz6wQ PMbmYti9KDxP1GN5xvtVFWuodPTXqd5JVEugWP77yQkVSRTkMkk9xudkH0LYHXLibS QxSC+2lhM4/Tg== To: Miguel Ojeda , Wedson Almeida Filho , Alex Gaynor From: Benno Lossin Cc: Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Andreas Hindborg , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Asahi Lina Subject: [PATCH 2/7] rust: add derive macro for `Zeroable` Message-ID: <20230624092330.157338-2-benno.lossin@proton.me> In-Reply-To: <20230624092330.157338-1-benno.lossin@proton.me> References: <20230624092330.157338-1-benno.lossin@proton.me> Feedback-ID: 71780778:user:proton MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: rust-for-linux@vger.kernel.org Add a derive proc-macro for the `Zeroable` trait. The macro supports structs where every field implements the `Zeroable` trait. This way `unsafe` implementations can be avoided. The macro is split into two parts: - a proc-macro to parse generics into impl and ty generics, - a declarative macro that expands to the impl block. Suggested-by: Asahi Lina Signed-off-by: Benno Lossin --- rust/kernel/init/macros.rs | 28 ++++++++++++++++++++++++++++ rust/kernel/prelude.rs | 2 +- rust/macros/lib.rs | 20 ++++++++++++++++++++ rust/macros/quote.rs | 6 ++++++ rust/macros/zeroable.rs | 25 +++++++++++++++++++++++++ 5 files changed, 80 insertions(+), 1 deletion(-) create mode 100644 rust/macros/zeroable.rs diff --git a/rust/kernel/init/macros.rs b/rust/kernel/init/macros.rs index fbaebd34f218..e8165ff53a94 100644 --- a/rust/kernel/init/macros.rs +++ b/rust/kernel/init/macros.rs @@ -1213,3 +1213,31 @@ macro_rules! __init_internal { ); }; } + +#[doc(hidden)] +#[macro_export] +macro_rules! __derive_zeroable { + (parse_input: + @sig( + $(#[$($struct_attr:tt)*])* + $vis:vis struct $name:ident + $(where $($whr:tt)*)? + ), + @impl_generics($($impl_generics:tt)*), + @ty_generics($($ty_generics:tt)*), + @body({ + $( + $(#[$($field_attr:tt)*])* + $field:ident : $field_ty:ty + ),* $(,)? + }), + ) =3D> { + // SAFETY: every field type implements `Zeroable` and padding byte= s may be zero. + #[automatically_derived] + unsafe impl<$($impl_generics)*> $crate::Zeroable for $name<$($ty_g= enerics)*> + where + $($field_ty: $crate::Zeroable,)* + $($($whr)*)? + {} + }; +} diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index c28587d68ebc..ae21600970b3 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -18,7 +18,7 @@ pub use alloc::{boxed::Box, vec::Vec}; #[doc(no_inline)] -pub use macros::{module, pin_data, pinned_drop, vtable}; +pub use macros::{module, pin_data, pinned_drop, vtable, Zeroable}; pub use super::build_assert; diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 3fc74cb4ea19..9f056a5c780a 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -10,6 +10,7 @@ mod pin_data; mod pinned_drop; mod vtable; +mod zeroable; use proc_macro::TokenStream; @@ -246,3 +247,22 @@ pub fn pin_data(inner: TokenStream, item: TokenStream)= -> TokenStream { pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream { pinned_drop::pinned_drop(args, input) } + +/// Derives the [`Zeroable`] trait for the given struct. +/// +/// This can only be used for structs where every field implements the [`Z= eroable`] trait. +/// +/// # Examples +/// +/// ```rust +/// #[derive(Zeroable)] +/// pub struct DriverData { +/// id: i64, +/// buf_ptr: *mut u8, +/// len: usize, +/// } +/// ``` +#[proc_macro_derive(Zeroable)] +pub fn derive_zeroable(input: TokenStream) -> TokenStream { + zeroable::derive(input) +} diff --git a/rust/macros/quote.rs b/rust/macros/quote.rs index dddbb4e6f4cb..b76c198a4ed5 100644 --- a/rust/macros/quote.rs +++ b/rust/macros/quote.rs @@ -124,6 +124,12 @@ macro_rules! quote_spanned { )); quote_spanned!(@proc $v $span $($tt)*); }; + (@proc $v:ident $span:ident ; $($tt:tt)*) =3D> { + $v.push(::proc_macro::TokenTree::Punct( + ::proc_macro::Punct::new(';', ::proc_macro::Spacing::Alone= ) + )); + quote_spanned!(@proc $v $span $($tt)*); + }; (@proc $v:ident $span:ident $id:ident $($tt:tt)*) =3D> { $v.push(::proc_macro::TokenTree::Ident(::proc_macro::Ident::new(st= ringify!($id), $span))); quote_spanned!(@proc $v $span $($tt)*); diff --git a/rust/macros/zeroable.rs b/rust/macros/zeroable.rs new file mode 100644 index 000000000000..cddb866c44ef --- /dev/null +++ b/rust/macros/zeroable.rs @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 + +use crate::helpers::{parse_generics, Generics}; +use proc_macro::TokenStream; + +pub(crate) fn derive(input: TokenStream) -> TokenStream { + let ( + Generics { + impl_generics, + ty_generics, + }, + mut rest, + ) =3D parse_generics(input); + // This should be the body of the struct `{...}`. + let last =3D rest.pop(); + quote! { + ::kernel::__derive_zeroable!( + parse_input: + @sig(#(#rest)*), + @impl_generics(#(#impl_generics)*), + @ty_generics(#(#ty_generics)*), + @body(#last), + ); + } +} -- 2.41.0