From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 109E529AB1D; Mon, 7 Jul 2025 13:32:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751895128; cv=none; b=Nunxcm+i+XqnkFGYmzELRtGlxYLIy8KIsS6ze2Yl442XhGzfvPO75sB+kO+OSXdAP91FiqktYLAUoAfaV08zJEPvqb9CuAValAVPBMbSE572CFbRR3CGku/lxm6+h6gDvaaJoMDpUcy399T8mQnKwcXauPElvgKVjWXHp0Isxuc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751895128; c=relaxed/simple; bh=2YIwwnFSN+fDOy0TmIgAKz1LQndsAk+izFq3MdUVAOE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=I2w/WDJV0yVQdFn5b3y7CIneRNEFfxskPFvSOwayOmOMmJNRrvP973pKzKQ56MBZtNciK/Kvs/lkwUvLGWhO3UdIFpx98di0hTM+lwJr/DjzOzQBfrq/xS7nHvJVbaJq8LcSwEHzz3Uka5XsRDbbCAw6pH2snUVwIxo0OEIzZeU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eUeFLERV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eUeFLERV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A39A1C4CEF4; Mon, 7 Jul 2025 13:32:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751895127; bh=2YIwwnFSN+fDOy0TmIgAKz1LQndsAk+izFq3MdUVAOE=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=eUeFLERVlY2Lz8CDJ68r2ONcfhKseuXe3tRbNb7SrY6a66wKxfTxMNQv27VpF+q1I +/M5kiK+wmQ6ZPHidPAgkN3bU+gUWyhVhwCQP7eM+gdpPv5dh10pq/TTm3cbA5R343 PBmhFjNw7yGwFe2s/+eGpeRvrOEDkn4ws+r23AbeyFjItOQiAmX2W3gO+OvjrMWQFU jGsbbGhL+cetoMsnV+grRFLeBXLemq6jY720i1B+QPO+VUQ+QTxslAtRZAdl757Ose msmRtYYrSaHujDsaepJAXWljWeOSCQV9uy1uEpOJEYFzoVHiI9W+9Xgjtw5MTjrosS 5F6w4mgvAxlWQ== From: Andreas Hindborg Date: Mon, 07 Jul 2025 15:29:09 +0200 Subject: [PATCH v15 5/7] rust: module: update the module macro with module parameter support Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250707-module-params-v3-v15-5-c1f4269a57b9@kernel.org> References: <20250707-module-params-v3-v15-0-c1f4269a57b9@kernel.org> In-Reply-To: <20250707-module-params-v3-v15-0-c1f4269a57b9@kernel.org> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Alice Ryhl , Masahiro Yamada , Nathan Chancellor , Luis Chamberlain , Danilo Krummrich , Benno Lossin , Benno Lossin , Nicolas Schier Cc: Trevor Gross , Adam Bratschi-Kaye , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Petr Pavlu , Sami Tolvanen , Daniel Gomez , Simona Vetter , Greg KH , Fiona Behrens , Daniel Almeida , linux-modules@vger.kernel.org, Andreas Hindborg X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=13520; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=2YIwwnFSN+fDOy0TmIgAKz1LQndsAk+izFq3MdUVAOE=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBoa8u3QgQakqkaGtZFh1bxTyECSwDoUc6xm5eQf MWOc/16csmJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaGvLtwAKCRDhuBo+eShj d64PD/4mux3V8xSdg4KgCDnv0BDFmC51T8cvXH9GW37JYImXkPD8uo8e+RD0Vtvz/8ePBpxejUp +eZJ2lwIrB2FO414K3xUT8gcv1uCiYoHrIICoUzdWafiDYlK2y9HsWW8SBtIe80SF9wCYZwwnj5 N+pSGxs4bJEKGKfuK+sNNcIQwK63Fn+xc3RivpAbMiCnpBqAHPlktnMDyrUMelWhuidGP8uunt0 Q4KAZ8klSMNnOHj9d2ftK5hVeX4v1H2f2Wae72Mg0giIq4EnCttWnBufvazSP0LZ7hR27vEw9gm BuH/p3szLa6gHaBReIonGP1QPo/JmOrkwiB7+l+Zlq8MuxIqlG6yr42uHWPD9tzMl0T66fzP5L+ NbrwKjjrXNxzmcPuqAEGXF/dugjbVPPccdYZhd6DQIednjtdi6uiyQuIy/RAQaO6DBBQUaMRQfr YuISOnoqNxY+zXyYHR9gCM6kVZntVucjA2eqDlHkIRWer9stg/I8jEcg1EszJbeJ6058mKphMpm Hve6cm8M0vfOUKhvQY8zJsrcEVzbV1isnVCOio+JIbClUt2q0/Bb5Nm8W4CBbzatUfk+yAjfP7n 4kj7H7XZptvxYhNG0KKNfipGbXaemgzemgr0wAwxBHQq3wSHCHtrH0TFqaU9aazdCdg+5puEBJi o6K7B4af66KSe2g== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 Allow module parameters to be declared in the rust `module!` macro. Reviewed-by: Benno Lossin Signed-off-by: Andreas Hindborg --- rust/macros/helpers.rs | 25 +++++++ rust/macros/lib.rs | 31 +++++++++ rust/macros/module.rs | 178 ++++++++++++++++++++++++++++++++++++++++++++++--- 3 files changed, 224 insertions(+), 10 deletions(-) diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs index e2602be402c10..365d7eb499c08 100644 --- a/rust/macros/helpers.rs +++ b/rust/macros/helpers.rs @@ -10,6 +10,17 @@ pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option { } } +pub(crate) fn try_sign(it: &mut token_stream::IntoIter) -> Option { + let peek = it.clone().next(); + match peek { + Some(TokenTree::Punct(punct)) if punct.as_char() == '-' => { + let _ = it.next(); + Some(punct.as_char()) + } + _ => None, + } +} + pub(crate) fn try_literal(it: &mut token_stream::IntoIter) -> Option { if let Some(TokenTree::Literal(literal)) = it.next() { Some(literal.to_string()) @@ -103,3 +114,17 @@ pub(crate) fn file() -> String { proc_macro::Span::call_site().file() } } + +/// Parse a token stream of the form `expected_name: "value",` and return the +/// string in the position of "value". +/// +/// # Panics +/// +/// - On parse error. +pub(crate) fn expect_string_field(it: &mut token_stream::IntoIter, expected_name: &str) -> String { + assert_eq!(expect_ident(it), expected_name); + assert_eq!(expect_punct(it), ':'); + let string = expect_string(it); + assert_eq!(expect_punct(it), ','); + string +} diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index fa847cf3a9b5f..2fb520dc930af 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -28,6 +28,30 @@ /// The `type` argument should be a type which implements the [`Module`] /// trait. Also accepts various forms of kernel metadata. /// +/// The `params` field describe module parameters. Each entry has the form +/// +/// ```ignore +/// parameter_name: type { +/// default: default_value, +/// description: "Description", +/// } +/// ``` +/// +/// `type` may be one of +/// +/// - [`i8`] +/// - [`u8`] +/// - [`i8`] +/// - [`u8`] +/// - [`i16`] +/// - [`u16`] +/// - [`i32`] +/// - [`u32`] +/// - [`i64`] +/// - [`u64`] +/// - [`isize`] +/// - [`usize`] +/// /// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) /// /// [`Module`]: ../kernel/trait.Module.html @@ -44,6 +68,12 @@ /// description: "My very own kernel module!", /// license: "GPL", /// alias: ["alternate_module_name"], +/// params: { +/// my_parameter: i64 { +/// default: 1, +/// description: "This parameter has a default of 1", +/// }, +/// }, /// } /// /// struct MyModule(i32); @@ -52,6 +82,7 @@ /// fn init(_module: &'static ThisModule) -> Result { /// let foo: i32 = 42; /// pr_info!("I contain: {}\n", foo); +/// pr_info!("i32 param is: {}\n", module_parameters::my_parameter.read()); /// Ok(Self(foo)) /// } /// } diff --git a/rust/macros/module.rs b/rust/macros/module.rs index 1a867a1e787ed..c1400597774a5 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -26,6 +26,7 @@ struct ModInfoBuilder<'a> { module: &'a str, counter: usize, buffer: String, + param_buffer: String, } impl<'a> ModInfoBuilder<'a> { @@ -34,10 +35,11 @@ fn new(module: &'a str) -> Self { module, counter: 0, buffer: String::new(), + param_buffer: String::new(), } } - fn emit_base(&mut self, field: &str, content: &str, builtin: bool) { + fn emit_base(&mut self, field: &str, content: &str, builtin: bool, param: bool) { let string = if builtin { // Built-in modules prefix their modinfo strings by `module.`. format!( @@ -51,8 +53,14 @@ fn emit_base(&mut self, field: &str, content: &str, builtin: bool) { format!("{field}={content}\0") }; + let buffer = if param { + &mut self.param_buffer + } else { + &mut self.buffer + }; + write!( - &mut self.buffer, + buffer, " {cfg} #[doc(hidden)] @@ -75,20 +83,119 @@ fn emit_base(&mut self, field: &str, content: &str, builtin: bool) { self.counter += 1; } - fn emit_only_builtin(&mut self, field: &str, content: &str) { - self.emit_base(field, content, true) + fn emit_only_builtin(&mut self, field: &str, content: &str, param: bool) { + self.emit_base(field, content, true, param) } - fn emit_only_loadable(&mut self, field: &str, content: &str) { - self.emit_base(field, content, false) + fn emit_only_loadable(&mut self, field: &str, content: &str, param: bool) { + self.emit_base(field, content, false, param) } fn emit(&mut self, field: &str, content: &str) { - self.emit_only_builtin(field, content); - self.emit_only_loadable(field, content); + self.emit_internal(field, content, false); + } + + fn emit_internal(&mut self, field: &str, content: &str, param: bool) { + self.emit_only_builtin(field, content, param); + self.emit_only_loadable(field, content, param); + } + + fn emit_param(&mut self, field: &str, param: &str, content: &str) { + let content = format!("{param}:{content}", param = param, content = content); + self.emit_internal(field, &content, true); + } + + fn emit_params(&mut self, info: &ModuleInfo) { + let Some(params) = &info.params else { + return; + }; + + for param in params { + let ops = param_ops_path(¶m.ptype); + + // Note: The spelling of these fields is dictated by the user space + // tool `modinfo`. + self.emit_param("parmtype", ¶m.name, ¶m.ptype); + self.emit_param("parm", ¶m.name, ¶m.description); + + write!( + self.param_buffer, + " + pub(crate) static {param_name}: + ::kernel::module_param::ModuleParamAccess<{param_type}> = + ::kernel::module_param::ModuleParamAccess::new({param_default}); + + const _: () = {{ + #[link_section = \"__param\"] + #[used] + static __{module_name}_{param_name}_struct: + ::kernel::module_param::KernelParam = + ::kernel::module_param::KernelParam::new( + ::kernel::bindings::kernel_param {{ + name: if ::core::cfg!(MODULE) {{ + ::kernel::c_str!(\"{param_name}\").as_bytes_with_nul() + }} else {{ + ::kernel::c_str!(\"{module_name}.{param_name}\") + .as_bytes_with_nul() + }}.as_ptr(), + // SAFETY: `__this_module` is constructed by the kernel at load + // time and will not be freed until the module is unloaded. + #[cfg(MODULE)] + mod_: unsafe {{ + core::ptr::from_ref(&::kernel::bindings::__this_module) + .cast_mut() + }}, + #[cfg(not(MODULE))] + mod_: ::core::ptr::null_mut(), + ops: core::ptr::from_ref(&{ops}), + perm: 0, // Will not appear in sysfs + level: -1, + flags: 0, + __bindgen_anon_1: ::kernel::bindings::kernel_param__bindgen_ty_1 {{ + arg: {param_name}.as_void_ptr() + }}, + }} + ); + }}; + ", + module_name = info.name, + param_type = param.ptype, + param_default = param.default, + param_name = param.name, + ops = ops, + ) + .unwrap(); + } + } +} + +fn param_ops_path(param_type: &str) -> &'static str { + match param_type { + "i8" => "::kernel::module_param::PARAM_OPS_I8", + "u8" => "::kernel::module_param::PARAM_OPS_U8", + "i16" => "::kernel::module_param::PARAM_OPS_I16", + "u16" => "::kernel::module_param::PARAM_OPS_U16", + "i32" => "::kernel::module_param::PARAM_OPS_I32", + "u32" => "::kernel::module_param::PARAM_OPS_U32", + "i64" => "::kernel::module_param::PARAM_OPS_I64", + "u64" => "::kernel::module_param::PARAM_OPS_U64", + "isize" => "::kernel::module_param::PARAM_OPS_ISIZE", + "usize" => "::kernel::module_param::PARAM_OPS_USIZE", + t => panic!("Unsupported parameter type {}", t), } } +fn expect_param_default(param_it: &mut token_stream::IntoIter) -> String { + assert_eq!(expect_ident(param_it), "default"); + assert_eq!(expect_punct(param_it), ':'); + let sign = try_sign(param_it); + let default = try_literal(param_it).expect("Expected default param value"); + assert_eq!(expect_punct(param_it), ','); + let mut value = sign.map(String::from).unwrap_or_default(); + value.push_str(&default); + value +} + #[derive(Debug, Default)] struct ModuleInfo { type_: String, @@ -99,6 +206,50 @@ struct ModuleInfo { description: Option, alias: Option>, firmware: Option>, + params: Option>, +} + +#[derive(Debug)] +struct Parameter { + name: String, + ptype: String, + default: String, + description: String, +} + +fn expect_params(it: &mut token_stream::IntoIter) -> Vec { + let params = expect_group(it); + assert_eq!(params.delimiter(), Delimiter::Brace); + let mut it = params.stream().into_iter(); + let mut parsed = Vec::new(); + + loop { + let param_name = match it.next() { + Some(TokenTree::Ident(ident)) => ident.to_string(), + Some(_) => panic!("Expected Ident or end"), + None => break, + }; + + assert_eq!(expect_punct(&mut it), ':'); + let param_type = expect_ident(&mut it); + let group = expect_group(&mut it); + assert_eq!(group.delimiter(), Delimiter::Brace); + assert_eq!(expect_punct(&mut it), ','); + + let mut param_it = group.stream().into_iter(); + let param_default = expect_param_default(&mut param_it); + let param_description = expect_string_field(&mut param_it, "description"); + expect_end(&mut param_it); + + parsed.push(Parameter { + name: param_name, + ptype: param_type, + default: param_default, + description: param_description, + }) + } + + parsed } impl ModuleInfo { @@ -114,6 +265,7 @@ fn parse(it: &mut token_stream::IntoIter) -> Self { "license", "alias", "firmware", + "params", ]; const REQUIRED_KEYS: &[&str] = &["type", "name", "license"]; let mut seen_keys = Vec::new(); @@ -140,6 +292,7 @@ fn parse(it: &mut token_stream::IntoIter) -> Self { "license" => info.license = expect_string_ascii(it), "alias" => info.alias = Some(expect_string_array(it)), "firmware" => info.firmware = Some(expect_string_array(it)), + "params" => info.params = Some(expect_params(it)), _ => panic!("Unknown key \"{key}\". Valid keys are: {EXPECTED_KEYS:?}."), } @@ -205,7 +358,9 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { // Built-in modules also export the `file` modinfo string. let file = std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable"); - modinfo.emit_only_builtin("file", &file); + modinfo.emit_only_builtin("file", &file, false); + + modinfo.emit_params(&info); format!( " @@ -369,15 +524,18 @@ unsafe fn __exit() {{ __MOD.assume_init_drop(); }} }} - {modinfo} }} }} + mod module_parameters {{ + {params} + }} ", type_ = info.type_, name = info.name, ident = ident, modinfo = modinfo.buffer, + params = modinfo.param_buffer, initcall_section = ".initcall6.init" ) .parse() -- 2.47.2