From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx> This patch includes changes required for Rust kernel modules to utilize module parameters. This code implements read only support for integer types without `sysfs` support. This code is a reduced and updated version of code by Adam available in the original `rust` branch [1]. [1] https://github.com/Rust-for-Linux/linux/tree/bc22545f38d74473cfef3e9fd65432733435b79f Cc: Adam Bratschi-Kaye <ark.email@xxxxxxxxx> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx> --- I have patches queued up for `rnull` that depend on this patch. --- rust/bindings/bindings_helper.h | 1 + rust/kernel/lib.rs | 2 + rust/kernel/module_param.rs | 339 ++++++++++++++++++++++++++++++++ rust/macros/helpers.rs | 8 + rust/macros/module.rs | 230 ++++++++++++++++++++-- samples/rust/rust_minimal.rs | 10 + 6 files changed, 571 insertions(+), 19 deletions(-) create mode 100644 rust/kernel/module_param.rs diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index ddb5644d4fd9..767169f46f10 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -25,3 +25,4 @@ const gfp_t RUST_CONST_HELPER_GFP_KERNEL = GFP_KERNEL; const gfp_t RUST_CONST_HELPER_GFP_KERNEL_ACCOUNT = GFP_KERNEL_ACCOUNT; const gfp_t RUST_CONST_HELPER_GFP_NOWAIT = GFP_NOWAIT; const gfp_t RUST_CONST_HELPER___GFP_ZERO = __GFP_ZERO; +const size_t RUST_CONST_HELPER_PAGE_SIZE = PAGE_SIZE; diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index fbd91a48ff8b..7cc2730e572f 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -33,6 +33,8 @@ pub mod ioctl; #[cfg(CONFIG_KUNIT)] pub mod kunit; +#[doc(hidden)] +pub mod module_param; #[cfg(CONFIG_NET)] pub mod net; pub mod prelude; diff --git a/rust/kernel/module_param.rs b/rust/kernel/module_param.rs new file mode 100644 index 000000000000..dc1108d20723 --- /dev/null +++ b/rust/kernel/module_param.rs @@ -0,0 +1,339 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Types for module parameters. +//! +//! C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h) + +use crate::{error::code::*, str::CStr}; + +/// Types that can be used for module parameters. +/// +/// Note that displaying the type in `sysfs` will fail if +/// [`core::str::from_utf8`] (as implemented through the [`core::fmt::Display`] +/// trait) writes more than [`PAGE_SIZE`] bytes (including an additional null +/// terminator). +/// +/// [`PAGE_SIZE`]: `bindings::PAGE_SIZE` +pub trait ModuleParam: core::fmt::Display + core::marker::Sized { + /// The `ModuleParam` will be used by the kernel module through this type. + /// + /// This may differ from `Self` if, for example, `Self` needs to track + /// ownership without exposing it or allocate extra space for other possible + /// parameter values. This is required to support string parameters in the + /// future. + type Value: ?Sized; + + /// Whether the parameter is allowed to be set without an argument. + /// + /// Setting this to `true` allows the parameter to be passed without an + /// argument (e.g. just `module.param` instead of `module.param=foo`). + const NOARG_ALLOWED: bool; + + /// Convert a parameter argument into the parameter value. + /// + /// `None` should be returned when parsing of the argument fails. + /// `arg == None` indicates that the parameter was passed without an + /// argument. If `NOARG_ALLOWED` is set to `false` then `arg` is guaranteed + /// to always be `Some(_)`. + /// + /// Parameters passed at boot time will be set before [`kmalloc`] is + /// available (even if the module is loaded at a later time). However, in + /// this case, the argument buffer will be valid for the entire lifetime of + /// the kernel. So implementations of this method which need to allocate + /// should first check that the allocator is available (with + /// [`crate::bindings::slab_is_available`]) and when it is not available + /// provide an alternative implementation which doesn't allocate. In cases + /// where the allocator is not available it is safe to save references to + /// `arg` in `Self`, but in other cases a copy should be made. + /// + /// [`kmalloc`]: ../../../include/linux/slab.h + fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self>; + + /// Get the current value of the parameter for use in the kernel module. + /// + /// This function should not be used directly. Instead use the wrapper + /// `read` which will be generated by [`macros::module`]. + fn value(&self) -> &Self::Value; + + /// Set the module parameter from a string. + /// + /// Used to set the parameter value at kernel initialization, when loading + /// the module or when set through `sysfs`. + /// + /// `param.arg` is a pointer to `*mut Self` as set up by the [`module!`] + /// macro. + /// + /// See `struct kernel_param_ops.set`. + /// + /// # Safety + /// + /// If `val` is non-null then it must point to a valid null-terminated + /// string. The `arg` field of `param` must be an instance of `Self`. + /// + /// # Invariants + /// + /// Currently, we only support read-only parameters that are not readable + /// from `sysfs`. Thus, this function is only called at kernel + /// initialization time, or at module load time, and we have exclusive + /// access to the parameter for the duration of the function. + /// + /// [`module!`]: macros::module + unsafe extern "C" fn set_param( + val: *const core::ffi::c_char, + param: *const crate::bindings::kernel_param, + ) -> core::ffi::c_int { + let arg = if val.is_null() { + None + } else { + // SAFETY: By function safety requirement, val is non-null and + // null-terminated. By C API contract, `val` is live and valid for + // reads for the duration of this function. + Some(unsafe { CStr::from_char_ptr(val).as_bytes() }) + }; + match Self::try_from_param_arg(arg) { + Some(new_value) => { + // SAFETY: `param` is guaranteed to be valid by C API contract + // and `arg` is guaranteed to point to an instance of `Self`. + let old_value = unsafe { (*param).__bindgen_anon_1.arg as *mut Self }; + // SAFETY: `old_value` is valid for writes, as we have exclusive + // access. `old_value` is pointing to an initialized static, an + // so it is properly initialized. + let _ = unsafe { core::ptr::replace(old_value, new_value) }; + 0 + } + None => EINVAL.to_errno(), + } + } + + /// Write a string representation of the current parameter value to `buf`. + /// + /// # Safety + /// + /// Must not be called. + /// + /// # Note + /// + /// This should not be called as we declare all parameters as read only. + unsafe extern "C" fn get_param( + _buf: *mut core::ffi::c_char, + _param: *const crate::bindings::kernel_param, + ) -> core::ffi::c_int { + 0 + } + + /// Drop the parameter. + /// + /// Called when unloading a module. + /// + /// # Safety + /// + /// The `arg` field of `param` must be an initialized instance of `Self`. + unsafe extern "C" fn free(arg: *mut core::ffi::c_void) { + // SAFETY: By function safety requirement, `arg` is an initialized + // instance of `Self`. By C API contract, `arg` will not be used after + // this function returns. + unsafe { core::ptr::drop_in_place(arg as *mut Self) }; + } +} + +/// Trait for parsing integers. +/// +/// Strings beginning with `0x`, `0o`, or `0b` are parsed as hex, octal, or +/// binary respectively. Strings beginning with `0` otherwise are parsed as +/// octal. Anything else is parsed as decimal. A leading `+` or `-` is also +/// permitted. Any string parsed by [`kstrtol()`] or [`kstrtoul()`] will be +/// successfully parsed. +/// +/// [`kstrtol()`]: https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtol +/// [`kstrtoul()`]: https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtoul +trait ParseInt: Sized { + fn from_str_radix(src: &str, radix: u32) -> Result<Self, core::num::ParseIntError>; + fn checked_neg(self) -> Option<Self>; + + fn from_str_unsigned(src: &str) -> Result<Self, core::num::ParseIntError> { + let (radix, digits) = if let Some(n) = src.strip_prefix("0x") { + (16, n) + } else if let Some(n) = src.strip_prefix("0X") { + (16, n) + } else if let Some(n) = src.strip_prefix("0o") { + (8, n) + } else if let Some(n) = src.strip_prefix("0O") { + (8, n) + } else if let Some(n) = src.strip_prefix("0b") { + (2, n) + } else if let Some(n) = src.strip_prefix("0B") { + (2, n) + } else if src.starts_with('0') { + (8, src) + } else { + (10, src) + }; + Self::from_str_radix(digits, radix) + } + + fn from_str(src: &str) -> Option<Self> { + match src.bytes().next() { + None => None, + Some(b'-') => Self::from_str_unsigned(&src[1..]).ok()?.checked_neg(), + Some(b'+') => Some(Self::from_str_unsigned(&src[1..]).ok()?), + Some(_) => Some(Self::from_str_unsigned(src).ok()?), + } + } +} + +macro_rules! impl_parse_int { + ($ty:ident) => { + impl ParseInt for $ty { + fn from_str_radix(src: &str, radix: u32) -> Result<Self, core::num::ParseIntError> { + $ty::from_str_radix(src, radix) + } + + fn checked_neg(self) -> Option<Self> { + self.checked_neg() + } + } + }; +} + +impl_parse_int!(i8); +impl_parse_int!(u8); +impl_parse_int!(i16); +impl_parse_int!(u16); +impl_parse_int!(i32); +impl_parse_int!(u32); +impl_parse_int!(i64); +impl_parse_int!(u64); +impl_parse_int!(isize); +impl_parse_int!(usize); + +macro_rules! impl_module_param { + ($ty:ident) => { + impl ModuleParam for $ty { + type Value = $ty; + + const NOARG_ALLOWED: bool = false; + + fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> { + let bytes = arg?; + let utf8 = core::str::from_utf8(bytes).ok()?; + <$ty as crate::module_param::ParseInt>::from_str(utf8) + } + + #[inline(always)] + fn value(&self) -> &Self::Value { + self + } + } + }; +} + +#[doc(hidden)] +#[macro_export] +/// Generate a static [`kernel_param_ops`](../../../include/linux/moduleparam.h) struct. +/// +/// # Examples +/// +/// ```ignore +/// make_param_ops!( +/// /// Documentation for new param ops. +/// PARAM_OPS_MYTYPE, // Name for the static. +/// MyType // A type which implements [`ModuleParam`]. +/// ); +/// ``` +macro_rules! make_param_ops { + ($ops:ident, $ty:ty) => { + $crate::make_param_ops!( + #[doc=""] + $ops, + $ty + ); + }; + ($(#[$meta:meta])* $ops:ident, $ty:ty) => { + $(#[$meta])* + /// + /// Static [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// struct generated by [`make_param_ops`]. + pub static $ops: $crate::bindings::kernel_param_ops = $crate::bindings::kernel_param_ops { + flags: if <$ty as $crate::module_param::ModuleParam>::NOARG_ALLOWED { + $crate::bindings::KERNEL_PARAM_OPS_FL_NOARG + } else { + 0 + }, + set: Some(<$ty as $crate::module_param::ModuleParam>::set_param), + get: Some(<$ty as $crate::module_param::ModuleParam>::get_param), + free: Some(<$ty as $crate::module_param::ModuleParam>::free), + }; + }; +} + +impl_module_param!(i8); +impl_module_param!(u8); +impl_module_param!(i16); +impl_module_param!(u16); +impl_module_param!(i32); +impl_module_param!(u32); +impl_module_param!(i64); +impl_module_param!(u64); +impl_module_param!(isize); +impl_module_param!(usize); + +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`i8`]. + PARAM_OPS_I8, + i8 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`u8`]. + PARAM_OPS_U8, + u8 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`i16`]. + PARAM_OPS_I16, + i16 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`u16`]. + PARAM_OPS_U16, + u16 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`i32`]. + PARAM_OPS_I32, + i32 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`u32`]. + PARAM_OPS_U32, + u32 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`i64`]. + PARAM_OPS_I64, + i64 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`u64`]. + PARAM_OPS_U64, + u64 +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`isize`]. + PARAM_OPS_ISIZE, + isize +); +make_param_ops!( + /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h) + /// for [`usize`]. + PARAM_OPS_USIZE, + usize +); diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs index 563dcd2b7ace..dc0b47879a8c 100644 --- a/rust/macros/helpers.rs +++ b/rust/macros/helpers.rs @@ -107,6 +107,14 @@ pub(crate) struct Generics { pub(crate) ty_generics: Vec<TokenTree>, } +pub(crate) fn get_string(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 +} + /// Parses the given `TokenStream` into `Generics` and the rest. /// /// The generics are not present in the rest, but a where clause might remain. diff --git a/rust/macros/module.rs b/rust/macros/module.rs index acd0393b5095..fc794855b99e 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 use crate::helpers::*; -use proc_macro::{token_stream, Delimiter, Literal, TokenStream, TokenTree}; +use proc_macro::{token_stream, Delimiter, Group, Literal, TokenStream, TokenTree}; use std::fmt::Write; fn expect_string_array(it: &mut token_stream::IntoIter) -> Vec<String> { @@ -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", field = field, content = content) }; + let buffer = if param { + &mut self.param_buffer + } else { + &mut self.buffer + }; + write!( - &mut self.buffer, + buffer, " {cfg} #[doc(hidden)] @@ -75,20 +83,190 @@ 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) { + if let Some(params) = &info.params { + assert_eq!(params.delimiter(), Delimiter::Brace); + + let mut it = params.stream().into_iter(); + + 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!(expect_punct(&mut it), ','); + + assert_eq!(group.delimiter(), Delimiter::Brace); + + let mut param_it = group.stream().into_iter(); + let param_default = get_param_default(&mut param_it); + let param_description = get_string(&mut param_it, "description"); + expect_end(&mut param_it); + + let (param_kernel_type, ops): (String, _) = ( + param_type.to_string(), + param_ops_path(¶m_type).to_string(), + ); + + self.emit_param("parmtype", ¶m_name, ¶m_kernel_type); + self.emit_param("parm", ¶m_name, ¶m_description); + let param_type_internal = param_type.clone(); + + let read_func = format!( + " + pub(crate) fn read(&self) + -> &<{param_type_internal} + as kernel::module_param::ModuleParam>::Value {{ + // Note: when we enable r/w parameters, we need to lock here. + + // SAFETY: Parameters do not need to be locked because they are + // read only or sysfs is not enabled. + unsafe {{ + <{param_type_internal} as kernel::module_param::ModuleParam>::value( + &__{name}_{param_name}_value + ) + }} + }} + ", + name = info.name, + param_name = param_name, + param_type_internal = param_type_internal, + ); + + let kparam = format!( + " + kernel::bindings::kernel_param__bindgen_ty_1 {{ + // SAFETY: Access through the resulting pointer is + // serialized by C side and only happens before module + // `init` or after module `drop` is called. + arg: unsafe {{ &__{name}_{param_name}_value }} + as *const _ as *mut core::ffi::c_void, + }}, + ", + name = info.name, + param_name = param_name, + ); + write!( + self.param_buffer, + " + static mut __{name}_{param_name}_value: {param_type_internal} = {param_default}; + + pub(crate) struct __{name}_{param_name}; + + impl __{name}_{param_name} {{ {read_func} }} + + pub(crate) const {param_name}: __{name}_{param_name} = __{name}_{param_name}; + + // Note: the C macro that generates the static structs for the `__param` section + // asks for them to be `aligned(sizeof(void *))`. However, that was put in place + // in 2003 in commit 38d5b085d2a0 (\"[PATCH] Fix over-alignment problem on x86-64\") + // to undo GCC over-alignment of static structs of >32 bytes. It seems that is + // not the case anymore, so we simplify to a transparent representation here + // in the expectation that it is not needed anymore. + // TODO: Revisit this to confirm the above comment and remove it if it happened. + /// Newtype to make `bindings::kernel_param` `Sync`. + #[repr(transparent)] + struct __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param); + + // SAFETY: C kernel handles serializing access to this type. We + // never access from Rust module. + unsafe impl Sync for __{name}_{param_name}_RacyKernelParam {{ + }} + + #[cfg(not(MODULE))] + const __{name}_{param_name}_name: *const core::ffi::c_char = + b\"{name}.{param_name}\\0\" as *const _ as *const core::ffi::c_char; + + #[cfg(MODULE)] + const __{name}_{param_name}_name: *const core::ffi::c_char = + b\"{param_name}\\0\" as *const _ as *const core::ffi::c_char; + + #[link_section = \"__param\"] + #[used] + static __{name}_{param_name}_struct: __{name}_{param_name}_RacyKernelParam = + __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param {{ + name: __{name}_{param_name}_name, + // 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 {{ &kernel::bindings::__this_module as *const _ as *mut _ }}, + #[cfg(not(MODULE))] + mod_: core::ptr::null_mut(), + // SAFETY: This static is actually constant as seen by + // module code. But we need a unique address for it, so it + // must be static. + ops: unsafe {{ &{ops} }} as *const kernel::bindings::kernel_param_ops, + perm: 0, // Will not appear in sysfs + level: -1, + flags: 0, + __bindgen_anon_1: {kparam} + }}); + ", + name = info.name, + param_type_internal = param_type_internal, + read_func = read_func, + param_default = param_default, + param_name = param_name, + ops = ops, + kparam = kparam, + ) + .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!("Unrecognized type {}", t), + } +} + +fn get_param_default(param_it: &mut token_stream::IntoIter) -> String { + assert_eq!(expect_ident(param_it), "default"); + assert_eq!(expect_punct(param_it), ':'); + let default = try_literal(param_it).expect("Expected default param value"); + assert_eq!(expect_punct(param_it), ','); + default +} + #[derive(Debug, Default)] struct ModuleInfo { type_: String, @@ -97,14 +275,22 @@ struct ModuleInfo { author: Option<String>, description: Option<String>, alias: Option<Vec<String>>, + params: Option<Group>, } impl ModuleInfo { fn parse(it: &mut token_stream::IntoIter) -> Self { let mut info = ModuleInfo::default(); - const EXPECTED_KEYS: &[&str] = - &["type", "name", "author", "description", "license", "alias"]; + const EXPECTED_KEYS: &[&str] = &[ + "type", + "name", + "author", + "description", + "license", + "alias", + "params", + ]; const REQUIRED_KEYS: &[&str] = &["type", "name", "license"]; let mut seen_keys = Vec::new(); @@ -131,6 +317,7 @@ fn parse(it: &mut token_stream::IntoIter) -> Self { "description" => info.description = Some(expect_string(it)), "license" => info.license = expect_string_ascii(it), "alias" => info.alias = Some(expect_string_array(it)), + "params" => info.params = Some(expect_group(it)), _ => panic!( "Unknown key \"{}\". Valid keys are: {:?}.", key, EXPECTED_KEYS @@ -174,23 +361,25 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { let info = ModuleInfo::parse(&mut it); let mut modinfo = ModInfoBuilder::new(info.name.as_ref()); - if let Some(author) = info.author { - modinfo.emit("author", &author); + if let Some(author) = &info.author { + modinfo.emit("author", author); } - if let Some(description) = info.description { - modinfo.emit("description", &description); + if let Some(description) = &info.description { + modinfo.emit("description", description); } modinfo.emit("license", &info.license); - if let Some(aliases) = info.alias { + if let Some(aliases) = &info.alias { for alias in aliases { - modinfo.emit("alias", &alias); + modinfo.emit("alias", alias); } } // 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!( " @@ -332,14 +521,17 @@ unsafe fn __exit() {{ __MOD = None; }} }} - {modinfo} }} }} + mod module_parameters {{ + {params} + }} ", type_ = info.type_, name = info.name, modinfo = modinfo.buffer, + params = modinfo.param_buffer, initcall_section = ".initcall6.init" ) .parse() diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs index 2a9eaab62d1c..359e6d8ec983 100644 --- a/samples/rust/rust_minimal.rs +++ b/samples/rust/rust_minimal.rs @@ -10,6 +10,12 @@ author: "Rust for Linux Contributors", description: "Rust minimal sample", license: "GPL", + params: { + test_parameter: i64 { + default: 1, + description: "This parameter has a default of 1", + }, + }, } struct RustMinimal { @@ -20,6 +26,10 @@ impl kernel::Module for RustMinimal { fn init(_module: &'static ThisModule) -> Result<Self> { pr_info!("Rust minimal sample (init)\n"); pr_info!("Am I built-in? {}\n", !cfg!(MODULE)); + pr_info!( + "My parameter: {}\n", + *module_parameters::test_parameter.read() + ); let mut numbers = Vec::new(); numbers.push(72, GFP_KERNEL)?; base-commit: f2661062f16b2de5d7b6a5c42a9a5c96326b8454 -- 2.45.2
