diff options
| -rw-r--r-- | MAINTAINERS | 3 | ||||
| -rw-r--r-- | drivers/media/radio/si470x/radio-si470x-i2c.c | 2 | ||||
| -rw-r--r-- | drivers/media/usb/dvb-usb-v2/lmedm04.c | 12 | ||||
| -rw-r--r-- | include/linux/moduleparam.h | 3 | ||||
| -rw-r--r-- | rust/kernel/lib.rs | 1 | ||||
| -rw-r--r-- | rust/kernel/module_param.rs | 182 | ||||
| -rw-r--r-- | rust/kernel/str.rs | 2 | ||||
| -rw-r--r-- | rust/kernel/str/parse_int.rs | 148 | ||||
| -rw-r--r-- | rust/kernel/sync.rs | 2 | ||||
| -rw-r--r-- | rust/kernel/sync/set_once.rs | 125 | ||||
| -rw-r--r-- | rust/macros/helpers.rs | 25 | ||||
| -rw-r--r-- | rust/macros/lib.rs | 31 | ||||
| -rw-r--r-- | rust/macros/module.rs | 198 | ||||
| -rw-r--r-- | samples/rust/rust_minimal.rs | 10 |
14 files changed, 717 insertions, 27 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 074d4351714c..05db8b2df438 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17522,6 +17522,7 @@ M: Luis Chamberlain <mcgrof@kernel.org> M: Petr Pavlu <petr.pavlu@suse.com> M: Daniel Gomez <da.gomez@kernel.org> R: Sami Tolvanen <samitolvanen@google.com> +R: Aaron Tomlin <atomlin@atomlin.com> L: linux-modules@vger.kernel.org L: linux-kernel@vger.kernel.org S: Maintained @@ -17531,6 +17532,8 @@ F: include/linux/module*.h F: kernel/module/ F: lib/test_kmod.c F: lib/tests/module/ +F: rust/kernel/module_param.rs +F: rust/macros/module.rs F: scripts/module* F: tools/testing/selftests/kmod/ F: tools/testing/selftests/module/ diff --git a/drivers/media/radio/si470x/radio-si470x-i2c.c b/drivers/media/radio/si470x/radio-si470x-i2c.c index cdd2ac198f2c..3932a449a1b1 100644 --- a/drivers/media/radio/si470x/radio-si470x-i2c.c +++ b/drivers/media/radio/si470x/radio-si470x-i2c.c @@ -10,7 +10,7 @@ /* driver definitions */ -#define DRIVER_AUTHOR "Joonyoung Shim <jy0922.shim@samsung.com>"; +#define DRIVER_AUTHOR "Joonyoung Shim <jy0922.shim@samsung.com>" #define DRIVER_CARD "Silicon Labs Si470x FM Radio" #define DRIVER_DESC "I2C radio driver for Si470x FM Radio Receivers" #define DRIVER_VERSION "1.0.2" diff --git a/drivers/media/usb/dvb-usb-v2/lmedm04.c b/drivers/media/usb/dvb-usb-v2/lmedm04.c index 0c510035805b..05c18b6de5c6 100644 --- a/drivers/media/usb/dvb-usb-v2/lmedm04.c +++ b/drivers/media/usb/dvb-usb-v2/lmedm04.c @@ -70,12 +70,12 @@ #include "ts2020.h" -#define LME2510_C_S7395 "dvb-usb-lme2510c-s7395.fw"; -#define LME2510_C_LG "dvb-usb-lme2510c-lg.fw"; -#define LME2510_C_S0194 "dvb-usb-lme2510c-s0194.fw"; -#define LME2510_C_RS2000 "dvb-usb-lme2510c-rs2000.fw"; -#define LME2510_LG "dvb-usb-lme2510-lg.fw"; -#define LME2510_S0194 "dvb-usb-lme2510-s0194.fw"; +#define LME2510_C_S7395 "dvb-usb-lme2510c-s7395.fw" +#define LME2510_C_LG "dvb-usb-lme2510c-lg.fw" +#define LME2510_C_S0194 "dvb-usb-lme2510c-s0194.fw" +#define LME2510_C_RS2000 "dvb-usb-lme2510c-rs2000.fw" +#define LME2510_LG "dvb-usb-lme2510-lg.fw" +#define LME2510_S0194 "dvb-usb-lme2510-s0194.fw" /* debug */ static int dvb_usb_lme2510_debug; diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 6907aedc4f74..915f32f7d888 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -26,6 +26,9 @@ /* Generic info of form tag = "info" */ #define MODULE_INFO(tag, info) \ + static_assert( \ + sizeof(info) - 1 == __builtin_strlen(info), \ + "MODULE_INFO(" #tag ", ...) contains embedded NUL byte"); \ static const char __UNIQUE_ID(modinfo)[] \ __used __section(".modinfo") __aligned(1) \ = __MODULE_INFO_PREFIX __stringify(tag) "=" info diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 12c4f0c1cdaf..6083dec1f190 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -112,6 +112,7 @@ pub mod list; pub mod maple_tree; pub mod miscdevice; pub mod mm; +pub mod module_param; #[cfg(CONFIG_NET)] pub mod net; pub mod num; diff --git a/rust/kernel/module_param.rs b/rust/kernel/module_param.rs new file mode 100644 index 000000000000..6a8a7a875643 --- /dev/null +++ b/rust/kernel/module_param.rs @@ -0,0 +1,182 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Support for module parameters. +//! +//! C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h) + +use crate::prelude::*; +use crate::str::BStr; +use bindings; +use kernel::sync::SetOnce; + +/// Newtype to make `bindings::kernel_param` [`Sync`]. +#[repr(transparent)] +#[doc(hidden)] +pub struct KernelParam(bindings::kernel_param); + +impl KernelParam { + #[doc(hidden)] + pub const fn new(val: bindings::kernel_param) -> Self { + Self(val) + } +} + +// SAFETY: C kernel handles serializing access to this type. We never access it +// from Rust module. +unsafe impl Sync for KernelParam {} + +/// Types that can be used for module parameters. +// NOTE: This trait is `Copy` because drop could produce unsoundness during teardown. +pub trait ModuleParam: Sized + Copy { + /// Parse a parameter argument into the parameter value. + fn try_from_param_arg(arg: &BStr) -> Result<Self>; +} + +/// 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`. +/// +/// See `struct kernel_param_ops.set`. +/// +/// # Safety +/// +/// - If `val` is non-null then it must point to a valid null-terminated string that must be valid +/// for reads for the duration of the call. +/// - `param` must be a pointer to a `bindings::kernel_param` initialized by the rust module macro. +/// The pointee must be valid for reads for the duration of the call. +/// +/// # Note +/// +/// - The safety requirements are satisfied by C API contract when this function is invoked by the +/// module subsystem C code. +/// - 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 c_char, param: *const bindings::kernel_param) -> c_int +where + T: ModuleParam, +{ + // NOTE: If we start supporting arguments without values, val _is_ allowed + // to be null here. + if val.is_null() { + // TODO: Use pr_warn_once available. + crate::pr_warn!("Null pointer passed to `module_param::set_param`"); + return EINVAL.to_errno(); + } + + // SAFETY: By function safety requirement, val is non-null, null-terminated + // and valid for reads for the duration of this function. + let arg = unsafe { CStr::from_char_ptr(val) }; + let arg: &BStr = arg.as_ref(); + + crate::error::from_result(|| { + let new_value = T::try_from_param_arg(arg)?; + + // SAFETY: By function safety requirements, this access is safe. + let container = unsafe { &*((*param).__bindgen_anon_1.arg.cast::<SetOnce<T>>()) }; + + container + .populate(new_value) + .then_some(0) + .ok_or(kernel::error::code::EEXIST) + }) +} + +macro_rules! impl_int_module_param { + ($ty:ident) => { + impl ModuleParam for $ty { + fn try_from_param_arg(arg: &BStr) -> Result<Self> { + <$ty as crate::str::parse_int::ParseInt>::from_str(arg) + } + } + }; +} + +impl_int_module_param!(i8); +impl_int_module_param!(u8); +impl_int_module_param!(i16); +impl_int_module_param!(u16); +impl_int_module_param!(i32); +impl_int_module_param!(u32); +impl_int_module_param!(i64); +impl_int_module_param!(u64); +impl_int_module_param!(isize); +impl_int_module_param!(usize); + +/// A wrapper for kernel parameters. +/// +/// This type is instantiated by the [`module!`] macro when module parameters are +/// defined. You should never need to instantiate this type directly. +/// +/// Note: This type is `pub` because it is used by module crates to access +/// parameter values. +pub struct ModuleParamAccess<T> { + value: SetOnce<T>, + default: T, +} + +// SAFETY: We only create shared references to the contents of this container, +// so if `T` is `Sync`, so is `ModuleParamAccess`. +unsafe impl<T: Sync> Sync for ModuleParamAccess<T> {} + +impl<T> ModuleParamAccess<T> { + #[doc(hidden)] + pub const fn new(default: T) -> Self { + Self { + value: SetOnce::new(), + default, + } + } + + /// Get a shared reference to the parameter value. + // Note: When sysfs access to parameters are enabled, we have to pass in a + // held lock guard here. + pub fn value(&self) -> &T { + self.value.as_ref().unwrap_or(&self.default) + } + + /// Get a mutable pointer to `self`. + /// + /// NOTE: In most cases it is not safe deref the returned pointer. + pub const fn as_void_ptr(&self) -> *mut c_void { + core::ptr::from_ref(self).cast_mut().cast() + } +} + +#[doc(hidden)] +/// Generate a static [`kernel_param_ops`](srctree/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) => { + #[doc(hidden)] + pub static $ops: $crate::bindings::kernel_param_ops = $crate::bindings::kernel_param_ops { + flags: 0, + set: Some(set_param::<$ty>), + get: None, + free: None, + }; + }; +} + +make_param_ops!(PARAM_OPS_I8, i8); +make_param_ops!(PARAM_OPS_U8, u8); +make_param_ops!(PARAM_OPS_I16, i16); +make_param_ops!(PARAM_OPS_U16, u16); +make_param_ops!(PARAM_OPS_I32, i32); +make_param_ops!(PARAM_OPS_U32, u32); +make_param_ops!(PARAM_OPS_I64, i64); +make_param_ops!(PARAM_OPS_U64, u64); +make_param_ops!(PARAM_OPS_ISIZE, isize); +make_param_ops!(PARAM_OPS_USIZE, usize); diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 6fcc9d47f12e..fa87779d2253 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -15,6 +15,8 @@ use core::{ pub use crate::prelude::CStr; +pub mod parse_int; + /// Byte string without UTF-8 validity guarantee. #[repr(transparent)] pub struct BStr([u8]); diff --git a/rust/kernel/str/parse_int.rs b/rust/kernel/str/parse_int.rs new file mode 100644 index 000000000000..48eb4c202984 --- /dev/null +++ b/rust/kernel/str/parse_int.rs @@ -0,0 +1,148 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Integer parsing functions. +//! +//! Integer parsing functions for parsing signed and unsigned integers +//! potentially prefixed with `0x`, `0o`, or `0b`. + +use crate::prelude::*; +use crate::str::BStr; +use core::ops::Deref; + +// Make `FromStrRadix` a public type with a private name. This seals +// `ParseInt`, that is, prevents downstream users from implementing the +// trait. +mod private { + use crate::prelude::*; + use crate::str::BStr; + + /// Trait that allows parsing a [`&BStr`] to an integer with a radix. + pub trait FromStrRadix: Sized { + /// Parse `src` to [`Self`] using radix `radix`. + fn from_str_radix(src: &BStr, radix: u32) -> Result<Self>; + + /// Tries to convert `value` into [`Self`] and negates the resulting value. + fn from_u64_negated(value: u64) -> Result<Self>; + } +} + +/// Extract the radix from an integer literal optionally prefixed with +/// one of `0x`, `0X`, `0o`, `0O`, `0b`, `0B`, `0`. +fn strip_radix(src: &BStr) -> (u32, &BStr) { + match src.deref() { + [b'0', b'x' | b'X', rest @ ..] => (16, rest.as_ref()), + [b'0', b'o' | b'O', rest @ ..] => (8, rest.as_ref()), + [b'0', b'b' | b'B', rest @ ..] => (2, rest.as_ref()), + // NOTE: We are including the leading zero to be able to parse + // literal `0` here. If we removed it as a radix prefix, we would + // not be able to parse `0`. + [b'0', ..] => (8, src), + _ => (10, src), + } +} + +/// Trait for parsing string representations of 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://docs.kernel.org/core-api/kernel-api.html#c.kstrtol +/// [`kstrtoul()`]: https://docs.kernel.org/core-api/kernel-api.html#c.kstrtoul +/// +/// # Examples +/// +/// ``` +/// # use kernel::str::parse_int::ParseInt; +/// # use kernel::b_str; +/// +/// assert_eq!(Ok(0u8), u8::from_str(b_str!("0"))); +/// +/// assert_eq!(Ok(0xa2u8), u8::from_str(b_str!("0xa2"))); +/// assert_eq!(Ok(-0xa2i32), i32::from_str(b_str!("-0xa2"))); +/// +/// assert_eq!(Ok(-0o57i8), i8::from_str(b_str!("-0o57"))); +/// assert_eq!(Ok(0o57i8), i8::from_str(b_str!("057"))); +/// +/// assert_eq!(Ok(0b1001i16), i16::from_str(b_str!("0b1001"))); +/// assert_eq!(Ok(-0b1001i16), i16::from_str(b_str!("-0b1001"))); +/// +/// assert_eq!(Ok(127i8), i8::from_str(b_str!("127"))); +/// assert!(i8::from_str(b_str!("128")).is_err()); +/// assert_eq!(Ok(-128i8), i8::from_str(b_str!("-128"))); +/// assert!(i8::from_str(b_str!("-129")).is_err()); +/// assert_eq!(Ok(255u8), u8::from_str(b_str!("255"))); +/// assert!(u8::from_str(b_str!("256")).is_err()); +/// ``` +pub trait ParseInt: private::FromStrRadix + TryFrom<u64> { + /// Parse a string according to the description in [`Self`]. + fn from_str(src: &BStr) -> Result<Self> { + match src.deref() { + [b'-', rest @ ..] => { + let (radix, digits) = strip_radix(rest.as_ref()); + // 2's complement values range from -2^(b-1) to 2^(b-1)-1. + // So if we want to parse negative numbers as positive and + // later multiply by -1, we have to parse into a larger + // integer. We choose `u64` as sufficiently large. + // + // NOTE: 128 bit integers are not available on all + // platforms, hence the choice of 64 bits. + let val = + u64::from_str_radix(core::str::from_utf8(digits).map_err(|_| EINVAL)?, radix) + .map_err(|_| EINVAL)?; + Self::from_u64_negated(val) + } + _ => { + let (radix, digits) = strip_radix(src); + Self::from_str_radix(digits, radix).map_err(|_| EINVAL) + } + } + } +} + +macro_rules! impl_parse_int { + ($($ty:ty),*) => { + $( + impl private::FromStrRadix for $ty { + fn from_str_radix(src: &BStr, radix: u32) -> Result<Self> { + <$ty>::from_str_radix(core::str::from_utf8(src).map_err(|_| EINVAL)?, radix) + .map_err(|_| EINVAL) + } + + fn from_u64_negated(value: u64) -> Result<Self> { + const ABS_MIN: u64 = { + #[allow(unused_comparisons)] + if <$ty>::MIN < 0 { + 1u64 << (<$ty>::BITS - 1) + } else { + 0 + } + }; + + if value > ABS_MIN { + return Err(EINVAL); + } + + if value == ABS_MIN { + return Ok(<$ty>::MIN); + } + + // SAFETY: The above checks guarantee that `value` fits into `Self`: + // - if `Self` is unsigned, then `ABS_MIN == 0` and thus we have returned above + // (either `EINVAL` or `MIN`). + // - if `Self` is signed, then we have that `0 <= value < ABS_MIN`. And since + // `ABS_MIN - 1` fits into `Self` by construction, `value` also does. + let value: Self = unsafe { value.try_into().unwrap_unchecked() }; + + Ok((!value).wrapping_add(1)) + } + } + + impl ParseInt for $ty {} + )* + }; +} + +impl_parse_int![i8, u8, i16, u16, i32, u32, i64, u64, isize, usize]; diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs index c94753d6413e..5df87e2bd212 100644 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@ -20,6 +20,7 @@ mod locked_by; pub mod poll; pub mod rcu; mod refcount; +mod set_once; pub use arc::{Arc, ArcBorrow, UniqueArc}; pub use completion::Completion; @@ -29,6 +30,7 @@ pub use lock::mutex::{new_mutex, Mutex, MutexGuard}; pub use lock::spinlock::{new_spinlock, SpinLock, SpinLockGuard}; pub use locked_by::LockedBy; pub use refcount::Refcount; +pub use set_once::SetOnce; /// Represents a lockdep class. It's a wrapper around C's `lock_class_key`. #[repr(transparent)] diff --git a/rust/kernel/sync/set_once.rs b/rust/kernel/sync/set_once.rs new file mode 100644 index 000000000000..bdba601807d8 --- /dev/null +++ b/rust/kernel/sync/set_once.rs @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! A container that can be initialized at most once. + +use super::atomic::{ + ordering::{Acquire, Relaxed, Release}, + Atomic, +}; +use core::{cell::UnsafeCell, mem::MaybeUninit}; + +/// A container that can be populated at most once. Thread safe. +/// +/// Once the a [`SetOnce`] is populated, it remains populated by the same object for the +/// lifetime `Self`. +/// +/// # Invariants +/// +/// - `init` may only increase in value. +/// - `init` may only assume values in the range `0..=2`. +/// - `init == 0` if and only if `value` is uninitialized. +/// - `init == 1` if and only if there is exactly one thread with exclusive +/// access to `self.value`. +/// - `init == 2` if and only if `value` is initialized and valid for shared +/// access. +/// +/// # Example +/// +/// ``` +/// # use kernel::sync::SetOnce; +/// let value = SetOnce::new(); +/// assert_eq!(None, value.as_ref()); +/// +/// let status = value.populate(42u8); +/// assert_eq!(true, status); +/// assert_eq!(Some(&42u8), value.as_ref()); +/// assert_eq!(Some(42u8), value.copy()); +/// +/// let status = value.populate(101u8); +/// assert_eq!(false, status); +/// assert_eq!(Some(&42u8), value.as_ref()); +/// assert_eq!(Some(42u8), value.copy()); +/// ``` +pub struct SetOnce<T> { + init: Atomic<u32>, + value: UnsafeCell<MaybeUninit<T>>, +} + +impl<T> Default for SetOnce<T> { + fn default() -> Self { + Self::new() + } +} + +impl<T> SetOnce<T> { + /// Create a new [`SetOnce`]. + /// + /// The returned instance will be empty. + pub const fn new() -> Self { + // INVARIANT: The container is empty and we initialize `init` to `0`. + Self { + value: UnsafeCell::new(MaybeUninit::uninit()), + init: Atomic::new(0), + } + } + + /// Get a reference to the contained object. + /// + /// Returns [`None`] if this [`SetOnce`] is empty. + pub fn as_ref(&self) -> Option<&T> { + if self.init.load(Acquire) == 2 { + // SAFETY: By the type invariants of `Self`, `self.init == 2` means that `self.value` + // is initialized and valid for shared access. + Some(unsafe { &*self.value.get().cast() }) + } else { + None + } + } + + /// Populate the [`SetOnce`]. + /// + /// Returns `true` if the [`SetOnce`] was successfully populated. + pub fn populate(&self, value: T) -> bool { + // INVARIANT: If the swap succeeds: + // - We increase `init`. + // - We write the valid value `1` to `init`. + // - Only one thread can succeed in this write, so we have exclusive access after the + // write. + if let Ok(0) = self.init.cmpxchg(0, 1, Relaxed) { + // SAFETY: By the type invariants of `Self`, the fact that we succeeded in writing `1` + // to `self.init` means we obtained exclusive access to `self.value`. + unsafe { core::ptr::write(self.value.get().cast(), value) }; + // INVARIANT: + // - We increase `init`. + // - We write the valid value `2` to `init`. + // - We release our exclusive access to `self.value` and it is now valid for shared + // access. + self.init.store(2, Release); + true + } else { + false + } + } + + /// Get a copy of the contained object. + /// + /// Returns [`None`] if the [`SetOnce`] is empty. + pub fn copy(&self) -> Option<T> + where + T: Copy, + { + self.as_ref().copied() + } +} + +impl<T> Drop for SetOnce<T> { + fn drop(&mut self) { + if *self.init.get_mut() == 2 { + let value = self.value.get_mut(); + // SAFETY: By the type invariants of `Self`, `self.init == 2` means that `self.value` + // contains a valid value. We have exclusive access, as we hold a `mut` reference to + // `self`. + unsafe { value.assume_init_drop() }; + } + } +} diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs index e2602be402c1..365d7eb499c0 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<String> { } } +pub(crate) fn try_sign(it: &mut token_stream::IntoIter) -> Option<char> { + 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<String> { 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 793f712dbf7c..b38002151871 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -29,6 +29,30 @@ use proc_macro::TokenStream; /// 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 @@ -45,6 +69,12 @@ use proc_macro::TokenStream; /// 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); @@ -53,6 +83,7 @@ use proc_macro::TokenStream; /// fn init(_module: &'static ThisModule) -> Result<Self> { /// 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 49131ff3e097..80cb9b16f5aa 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 @@ impl<'a> ModInfoBuilder<'a> { 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 @@ impl<'a> ModInfoBuilder<'a> { 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 @@ impl<'a> ModInfoBuilder<'a> { 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}\").to_bytes_with_nul() + }} else {{ + ::kernel::c_str!(\"{module_name}.{param_name}\") + .to_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 { alias: Option<Vec<String>>, firmware: Option<Vec<String>>, imports_ns: 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 { @@ -114,6 +265,7 @@ impl ModuleInfo { "alias", "firmware", "imports_ns", + "params", ]; const REQUIRED_KEYS: &[&str] = &["type", "name", "license"]; let mut seen_keys = Vec::new(); @@ -140,6 +292,7 @@ impl ModuleInfo { "alias" => info.alias = Some(expect_string_array(it)), "firmware" => info.firmware = Some(expect_string_array(it)), "imports_ns" => info.imports_ns = Some(expect_string_array(it)), + "params" => info.params = Some(expect_params(it)), _ => panic!("Unknown key \"{key}\". Valid keys are: {EXPECTED_KEYS:?}."), } @@ -179,35 +332,37 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { // Rust does not allow hyphens in identifiers, use underscore instead. let ident = info.name.replace('-', "_"); let mut modinfo = ModInfoBuilder::new(ident.as_ref()); - if let Some(authors) = info.authors { + if let Some(authors) = &info.authors { for author in authors { - modinfo.emit("author", &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); } } - if let Some(imports) = info.imports_ns { + if let Some(imports) = &info.imports_ns { for ns in imports { - modinfo.emit("import_ns", &ns); + modinfo.emit("import_ns", ns); } } // 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!( " @@ -371,15 +526,18 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream { __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() diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs index 1fc7a1be6b6d..8eb9583571d7 100644 --- a/samples/rust/rust_minimal.rs +++ b/samples/rust/rust_minimal.rs @@ -10,6 +10,12 @@ module! { authors: ["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!( + "test_parameter: {}\n", + *module_parameters::test_parameter.value() + ); let mut numbers = KVec::new(); numbers.push(72, GFP_KERNEL)?; |