| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20240819133345.3438739-1-nmi@metaspace.dk>
Date: Mon, 19 Aug 2024 13:34:13 +0000
From: Andreas Hindborg <nmi@...aspace.dk>
To: Luis Chamberlain <mcgrof@...nel.org>, Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, Wedson Almeida Filho <wedsonaf@...il.com>
Cc: Andreas Hindborg <a.hindborg@...sung.com>, Adam Bratschi-Kaye <ark.email@...il.com>, Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, Björn Roy Baron <bjorn3_gh@...tonmail.com>, Benno Lossin <benno.lossin@...ton.me>, Alice Ryhl <aliceryhl@...gle.com>, Daniel Gomez <da.gomez@...sung.com>, rust-for-linux@...r.kernel.org, linux-modules@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] rust: add `module_params` macro
From: Andreas Hindborg <a.hindborg@...sung.com>
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].
Link: https://github.com/Rust-for-Linux/linux/tree/bc22545f38d74473cfef3e9fd65432733435b79f [1]
Cc: Adam Bratschi-Kaye <ark.email@...il.com>
Signed-off-by: Andreas Hindborg <a.hindborg@...sung.com>
---
Changes since v1 [2]:
- Remove support for params without values (`NOARG_ALLOWED`).
- Improve documentation for `try_from_param_arg`.
- Use prelude import.
- Refactor `try_from_param_arg` to return `Result`.
- Refactor `ParseInt::from_str` to return `Result`.
- Move C callable functions out of `ModuleParam` trait.
- Rename literal string field parser to `expect_string_field`.
- Move parameter parsing from generation to parsing stage.
- Use absolute type paths in macro code.
- Inline `kparam`and `read_func` values.
- Resolve TODO regarding alignment attributes.
- Remove unnecessary unsafe blocks in macro code.
- Improve error message for unrecognized parameter types.
- Do not use `self` receiver when reading parameter value.
- Add parameter documentation to `module!` macro.
- Use empty `enum` for parameter type.
- Use `addr_of_mut` to get address of parameter value variable.
- Enabled building of docs for for `module_param` module.
Link: https://lore.kernel.org/rust-for-linux/20240705111455.142790-1-nmi@metaspace.dk/ [2]
---
rust/kernel/error.rs | 2 -
rust/kernel/lib.rs | 1 +
rust/kernel/module_param.rs | 339 +++++++++++++++++++++++++++++++++++
rust/macros/helpers.rs | 8 +
rust/macros/lib.rs | 40 ++++-
rust/macros/module.rs | 229 ++++++++++++++++++++---
samples/rust/rust_minimal.rs | 10 ++
scripts/Makefile.build | 2 +-
8 files changed, 593 insertions(+), 38 deletions(-)
create mode 100644 rust/kernel/module_param.rs
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 145f5c397009..8532a09947d4 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -312,8 +312,6 @@ pub(crate) fn from_err_ptr<T>(ptr: *mut T) -> Result<*mut T> {
/// })
/// }
/// ```
-// TODO: Remove `dead_code` marker once an in-kernel client is available.
-#[allow(dead_code)]
pub(crate) fn from_result<T, F>(f: F) -> T
where
T: From<i16>,
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 274bdc1b0a82..2840237eb73b 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -38,6 +38,7 @@
pub mod ioctl;
#[cfg(CONFIG_KUNIT)]
pub mod kunit;
+pub mod module_param;
#[cfg(CONFIG_NET)]
pub mod net;
pub mod page;
diff --git a/rust/kernel/module_param.rs b/rust/kernel/module_param.rs
new file mode 100644
index 000000000000..9dfee0311d65
--- /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::prelude::*;
+
+/// 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;
+
+ /// Parse a parameter argument into the parameter value.
+ ///
+ /// `Err(_)` should be returned when parsing of the argument fails.
+ ///
+ /// 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: &'static [u8]) -> Result<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 T` 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 `T`.
+///
+/// # 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<T>(
+ val: *const core::ffi::c_char,
+ param: *const crate::bindings::kernel_param,
+) -> core::ffi::c_int
+where
+ T: ModuleParam,
+{
+ // NOTE: If we start supporting arguments without values, val _is_ allowed
+ // to be null here.
+ assert!(!val.is_null());
+
+ // 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.
+ let arg = unsafe { CStr::from_char_ptr(val).as_bytes() };
+
+ crate::error::from_result(|| {
+ let new_value = T::try_from_param_arg(arg)?;
+
+ // SAFETY: `param` is guaranteed to be valid by C API contract
+ // and `arg` is guaranteed to point to an instance of `T`.
+ let old_value = unsafe { (*param).__bindgen_anon_1.arg as *mut T };
+
+ // 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.
+ unsafe { core::ptr::replace(old_value, new_value) };
+ Ok(0)
+ })
+}
+
+/// 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.
+#[allow(clippy::extra_unused_type_parameters)]
+unsafe extern "C" fn get_param<T>(
+ _buf: *mut core::ffi::c_char,
+ _param: *const crate::bindings::kernel_param,
+) -> core::ffi::c_int
+where
+ T: ModuleParam,
+{
+ unreachable!("Parameters are not readable");
+}
+
+/// 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<T>(arg: *mut core::ffi::c_void)
+where
+ T: ModuleParam,
+{
+ // SAFETY: By function safety requirement, `arg` is an initialized
+ // instance of `T`. By C API contract, `arg` will not be used after
+ // this function returns.
+ unsafe { core::ptr::drop_in_place(arg as *mut T) };
+}
+
+/// 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>;
+
+ // NOTE: Required because `checked_neg` is not provided by any trait.
+ 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) -> Result<Self> {
+ match src.bytes().next() {
+ None => Err(EINVAL),
+ Some(b'-') => Self::from_str_unsigned(&src[1..])
+ .map_err(|_| EINVAL)?
+ .checked_neg()
+ .ok_or(EINVAL),
+ Some(b'+') => Self::from_str_unsigned(&src[1..]).map_err(|_| EINVAL),
+ Some(_) => Self::from_str_unsigned(src).map_err(|_| EINVAL),
+ }
+ }
+}
+
+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 = $ty;
+
+ fn try_from_param_arg(arg: &'static [u8]) -> Result<Self> {
+ let utf8 = core::str::from_utf8(arg)?;
+ <$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 = $crate::bindings::kernel_param_ops {
+ flags: 0,
+ set: Some(set_param::<$ty>),
+ get: Some(get_param::<$ty>),
+ free: Some(free::<$ty>),
+ };
+ };
+}
+
+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..49388907370d 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 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
+}
+
/// 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/lib.rs b/rust/macros/lib.rs
index 159e75292970..1d7bc99ec5e0 100644
--- a/rust/macros/lib.rs
+++ b/rust/macros/lib.rs
@@ -20,6 +20,30 @@
/// 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
@@ -36,21 +60,19 @@
/// 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;
///
/// impl kernel::Module for MyModule {
/// fn init() -> Result<Self> {
-/// // If the parameter is writeable, then the kparam lock must be
-/// // taken to read the parameter:
-/// {
-/// let lock = THIS_MODULE.kernel_param_lock();
-/// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock));
-/// }
-/// // If the parameter is read only, it can be read without locking
-/// // the kernel parameters:
-/// pr_info!("i32 param is: {}\n", my_i32.read());
+/// pr_info!("i32 param is: {}\n", module_parameters::my_parameter::read());
/// Ok(Self)
/// }
/// }
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
index 411dc103d82e..2fa9ed8e78ff 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", 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 +83,135 @@ 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 {
+ for param in params {
+ let ops = param_ops_path(¶m.ptype);
+
+ self.emit_param("parmtype", ¶m.name, ¶m.ptype);
+ self.emit_param("parm", ¶m.name, ¶m.description);
+
+ write!(
+ self.param_buffer,
+ "
+ static mut __{name}_{param_name}_value: {param_type} = {param_default};
+
+ pub(crate) enum {param_name} {{}}
+
+ impl {param_name} {{
+ pub(crate) fn read<'a>()
+ -> &'a <{param_type} 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} as ::kernel::module_param::ModuleParam>::value(
+ &__{name}_{param_name}_value
+ )
+ }}
+ }}
+ }}
+
+ /// 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(),
+ ops: &{ops} as *const ::kernel::bindings::kernel_param_ops,
+ perm: 0, // Will not appear in sysfs
+ level: -1,
+ flags: 0,
+ __bindgen_anon_1:
+ ::kernel::bindings::kernel_param__bindgen_ty_1 {{
+ // SAFETY: As this is evaluated in const context, it is
+ // safe to take a reference to a mut static.
+ arg: unsafe {{
+ ::core::ptr::addr_of_mut!(__{name}_{param_name}_value)
+ }}.cast::<::core::ffi::c_void>(),
+ }},
+ }});
+ ",
+ 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 default = try_literal(param_it).expect("Expected default param value");
+ assert_eq!(expect_punct(param_it), ',');
+ default
+}
+
#[derive(Debug, Default)]
struct ModuleInfo {
type_: String,
@@ -98,6 +221,50 @@ struct ModuleInfo {
description: Option<String>,
alias: Option<Vec<String>>,
firmware: Option<Vec<String>>,
+ params: Option<Vec<Parameter>>,
+}
+
+#[derive(Debug)]
+struct Parameter {
+ name: String,
+ ptype: String,
+ default: String,
+ description: String,
+}
+
+fn expect_params(it: &mut token_stream::IntoIter) -> Vec<Parameter> {
+ 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 {
@@ -112,6 +279,7 @@ 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 +308,7 @@ 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 \"{}\". Valid keys are: {:?}.",
key, EXPECTED_KEYS
@@ -183,28 +352,30 @@ 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);
}
}
- if let Some(firmware) = info.firmware {
+ if let Some(firmware) = &info.firmware {
for fw in firmware {
- modinfo.emit("firmware", &fw);
+ modinfo.emit("firmware", fw);
}
}
// 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!(
"
@@ -216,12 +387,14 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
// SAFETY: `__this_module` is constructed by the kernel at load time and will not be
// freed until the module is unloaded.
#[cfg(MODULE)]
- static THIS_MODULE: kernel::ThisModule = unsafe {{
- kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _)
+ static THIS_MODULE: ::kernel::ThisModule = unsafe {{
+ ::kernel::ThisModule::from_ptr(
+ &::kernel::bindings::__this_module as *const _ as *mut _
+ )
}};
#[cfg(not(MODULE))]
- static THIS_MODULE: kernel::ThisModule = unsafe {{
- kernel::ThisModule::from_ptr(core::ptr::null_mut())
+ static THIS_MODULE: ::kernel::ThisModule = unsafe {{
+ ::kernel::ThisModule::from_ptr(::core::ptr::null_mut())
}};
// Double nested modules, since then nobody can access the public items inside.
@@ -276,7 +449,8 @@ mod __module_init {{
#[doc(hidden)]
#[link_section = \"{initcall_section}\"]
#[used]
- pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
+ pub static __{name}_initcall: extern \"C\" fn()
+ -> ::core::ffi::c_int = __{name}_init;
#[cfg(not(MODULE))]
#[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
@@ -291,7 +465,7 @@ mod __module_init {{
#[cfg(not(MODULE))]
#[doc(hidden)]
#[no_mangle]
- pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
+ pub extern \"C\" fn __{name}_init() -> ::core::ffi::c_int {{
// SAFETY: This function is inaccessible to the outside due to the double
// module wrapping it. It is called exactly once by the C side via its
// placement above in the initcall section.
@@ -314,8 +488,8 @@ mod __module_init {{
/// # Safety
///
/// This function must only be called once.
- unsafe fn __init() -> core::ffi::c_int {{
- match <{type_} as kernel::Module>::init(&super::super::THIS_MODULE) {{
+ unsafe fn __init() -> ::core::ffi::c_int {{
+ match <{type_} as ::kernel::Module>::init(&super::super::THIS_MODULE) {{
Ok(m) => {{
// SAFETY: No data race, since `__MOD` can only be accessed by this
// module and there only `__init` and `__exit` access it. These
@@ -346,14 +520,17 @@ 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..d9bc2218d504 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)?;
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index efacca63c897..a65bd0233843 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -263,7 +263,7 @@ $(obj)/%.lst: $(obj)/%.c FORCE
# Compile Rust sources (.rs)
# ---------------------------------------------------------------------------
-rust_allowed_features := new_uninit
+rust_allowed_features := new_uninit,const_mut_refs
# `--out-dir` is required to avoid temporaries being created by `rustc` in the
# current working directory, which may be not accessible in the out-of-tree
base-commit: 7c626ce4bae1ac14f60076d00eafe71af30450ba
--
2.46.0
Powered by blists - more mailing lists