mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 04:31:50 +00:00
00280272a0
Rust's `unused_imports` lint covers both unused and redundant imports.
In the upcoming 1.78.0, the lint detects more cases of redundant imports
[1], e.g.:
error: the item `bindings` is imported redundantly
--> rust/kernel/print.rs:38:9
|
38 | use crate::bindings;
| ^^^^^^^^^^^^^^^ the item `bindings` is already defined by prelude
Most cases are `use crate::bindings`, plus a few other items like `Box`.
Thus clean them up.
Note that, in the `bindings` case, the message "defined by prelude"
above means the extern prelude, i.e. the `--extern` flags we pass.
Link: https://github.com/rust-lang/rust/pull/117772 [1]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240401212303.537355-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
414 lines
13 KiB
Rust
414 lines
13 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
|
|
|
|
//! Printing facilities.
|
|
//!
|
|
//! C header: [`include/linux/printk.h`](srctree/include/linux/printk.h)
|
|
//!
|
|
//! Reference: <https://www.kernel.org/doc/html/latest/core-api/printk-basics.html>
|
|
|
|
use core::{
|
|
ffi::{c_char, c_void},
|
|
fmt,
|
|
};
|
|
|
|
use crate::str::RawFormatter;
|
|
|
|
// Called from `vsprintf` with format specifier `%pA`.
|
|
#[no_mangle]
|
|
unsafe extern "C" fn rust_fmt_argument(
|
|
buf: *mut c_char,
|
|
end: *mut c_char,
|
|
ptr: *const c_void,
|
|
) -> *mut c_char {
|
|
use fmt::Write;
|
|
// SAFETY: The C contract guarantees that `buf` is valid if it's less than `end`.
|
|
let mut w = unsafe { RawFormatter::from_ptrs(buf.cast(), end.cast()) };
|
|
let _ = w.write_fmt(unsafe { *(ptr as *const fmt::Arguments<'_>) });
|
|
w.pos().cast()
|
|
}
|
|
|
|
/// Format strings.
|
|
///
|
|
/// Public but hidden since it should only be used from public macros.
|
|
#[doc(hidden)]
|
|
pub mod format_strings {
|
|
/// The length we copy from the `KERN_*` kernel prefixes.
|
|
const LENGTH_PREFIX: usize = 2;
|
|
|
|
/// The length of the fixed format strings.
|
|
pub const LENGTH: usize = 10;
|
|
|
|
/// Generates a fixed format string for the kernel's [`_printk`].
|
|
///
|
|
/// The format string is always the same for a given level, i.e. for a
|
|
/// given `prefix`, which are the kernel's `KERN_*` constants.
|
|
///
|
|
/// [`_printk`]: srctree/include/linux/printk.h
|
|
const fn generate(is_cont: bool, prefix: &[u8; 3]) -> [u8; LENGTH] {
|
|
// Ensure the `KERN_*` macros are what we expect.
|
|
assert!(prefix[0] == b'\x01');
|
|
if is_cont {
|
|
assert!(prefix[1] == b'c');
|
|
} else {
|
|
assert!(prefix[1] >= b'0' && prefix[1] <= b'7');
|
|
}
|
|
assert!(prefix[2] == b'\x00');
|
|
|
|
let suffix: &[u8; LENGTH - LENGTH_PREFIX] = if is_cont {
|
|
b"%pA\0\0\0\0\0"
|
|
} else {
|
|
b"%s: %pA\0"
|
|
};
|
|
|
|
[
|
|
prefix[0], prefix[1], suffix[0], suffix[1], suffix[2], suffix[3], suffix[4], suffix[5],
|
|
suffix[6], suffix[7],
|
|
]
|
|
}
|
|
|
|
// Generate the format strings at compile-time.
|
|
//
|
|
// This avoids the compiler generating the contents on the fly in the stack.
|
|
//
|
|
// Furthermore, `static` instead of `const` is used to share the strings
|
|
// for all the kernel.
|
|
pub static EMERG: [u8; LENGTH] = generate(false, bindings::KERN_EMERG);
|
|
pub static ALERT: [u8; LENGTH] = generate(false, bindings::KERN_ALERT);
|
|
pub static CRIT: [u8; LENGTH] = generate(false, bindings::KERN_CRIT);
|
|
pub static ERR: [u8; LENGTH] = generate(false, bindings::KERN_ERR);
|
|
pub static WARNING: [u8; LENGTH] = generate(false, bindings::KERN_WARNING);
|
|
pub static NOTICE: [u8; LENGTH] = generate(false, bindings::KERN_NOTICE);
|
|
pub static INFO: [u8; LENGTH] = generate(false, bindings::KERN_INFO);
|
|
pub static DEBUG: [u8; LENGTH] = generate(false, bindings::KERN_DEBUG);
|
|
pub static CONT: [u8; LENGTH] = generate(true, bindings::KERN_CONT);
|
|
}
|
|
|
|
/// Prints a message via the kernel's [`_printk`].
|
|
///
|
|
/// Public but hidden since it should only be used from public macros.
|
|
///
|
|
/// # Safety
|
|
///
|
|
/// The format string must be one of the ones in [`format_strings`], and
|
|
/// the module name must be null-terminated.
|
|
///
|
|
/// [`_printk`]: srctree/include/linux/_printk.h
|
|
#[doc(hidden)]
|
|
#[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
|
|
pub unsafe fn call_printk(
|
|
format_string: &[u8; format_strings::LENGTH],
|
|
module_name: &[u8],
|
|
args: fmt::Arguments<'_>,
|
|
) {
|
|
// `_printk` does not seem to fail in any path.
|
|
#[cfg(CONFIG_PRINTK)]
|
|
unsafe {
|
|
bindings::_printk(
|
|
format_string.as_ptr() as _,
|
|
module_name.as_ptr(),
|
|
&args as *const _ as *const c_void,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// Prints a message via the kernel's [`_printk`] for the `CONT` level.
|
|
///
|
|
/// Public but hidden since it should only be used from public macros.
|
|
///
|
|
/// [`_printk`]: srctree/include/linux/printk.h
|
|
#[doc(hidden)]
|
|
#[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
|
|
pub fn call_printk_cont(args: fmt::Arguments<'_>) {
|
|
// `_printk` does not seem to fail in any path.
|
|
//
|
|
// SAFETY: The format string is fixed.
|
|
#[cfg(CONFIG_PRINTK)]
|
|
unsafe {
|
|
bindings::_printk(
|
|
format_strings::CONT.as_ptr() as _,
|
|
&args as *const _ as *const c_void,
|
|
);
|
|
}
|
|
}
|
|
|
|
/// Performs formatting and forwards the string to [`call_printk`].
|
|
///
|
|
/// Public but hidden since it should only be used from public macros.
|
|
#[doc(hidden)]
|
|
#[cfg(not(testlib))]
|
|
#[macro_export]
|
|
#[allow(clippy::crate_in_macro_def)]
|
|
macro_rules! print_macro (
|
|
// The non-continuation cases (most of them, e.g. `INFO`).
|
|
($format_string:path, false, $($arg:tt)+) => (
|
|
// To remain sound, `arg`s must be expanded outside the `unsafe` block.
|
|
// Typically one would use a `let` binding for that; however, `format_args!`
|
|
// takes borrows on the arguments, but does not extend the scope of temporaries.
|
|
// Therefore, a `match` expression is used to keep them around, since
|
|
// the scrutinee is kept until the end of the `match`.
|
|
match format_args!($($arg)+) {
|
|
// SAFETY: This hidden macro should only be called by the documented
|
|
// printing macros which ensure the format string is one of the fixed
|
|
// ones. All `__LOG_PREFIX`s are null-terminated as they are generated
|
|
// by the `module!` proc macro or fixed values defined in a kernel
|
|
// crate.
|
|
args => unsafe {
|
|
$crate::print::call_printk(
|
|
&$format_string,
|
|
crate::__LOG_PREFIX,
|
|
args,
|
|
);
|
|
}
|
|
}
|
|
);
|
|
|
|
// The `CONT` case.
|
|
($format_string:path, true, $($arg:tt)+) => (
|
|
$crate::print::call_printk_cont(
|
|
format_args!($($arg)+),
|
|
);
|
|
);
|
|
);
|
|
|
|
/// Stub for doctests
|
|
#[cfg(testlib)]
|
|
#[macro_export]
|
|
macro_rules! print_macro (
|
|
($format_string:path, $e:expr, $($arg:tt)+) => (
|
|
()
|
|
);
|
|
);
|
|
|
|
// We could use a macro to generate these macros. However, doing so ends
|
|
// up being a bit ugly: it requires the dollar token trick to escape `$` as
|
|
// well as playing with the `doc` attribute. Furthermore, they cannot be easily
|
|
// imported in the prelude due to [1]. So, for the moment, we just write them
|
|
// manually, like in the C side; while keeping most of the logic in another
|
|
// macro, i.e. [`print_macro`].
|
|
//
|
|
// [1]: https://github.com/rust-lang/rust/issues/52234
|
|
|
|
/// Prints an emergency-level message (level 0).
|
|
///
|
|
/// Use this level if the system is unusable.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_emerg`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_emerg`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_emerg
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_emerg!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! pr_emerg (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::EMERG, false, $($arg)*)
|
|
)
|
|
);
|
|
|
|
/// Prints an alert-level message (level 1).
|
|
///
|
|
/// Use this level if action must be taken immediately.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_alert`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_alert`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_alert
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_alert!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! pr_alert (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::ALERT, false, $($arg)*)
|
|
)
|
|
);
|
|
|
|
/// Prints a critical-level message (level 2).
|
|
///
|
|
/// Use this level for critical conditions.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_crit`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_crit`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_crit
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_crit!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! pr_crit (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::CRIT, false, $($arg)*)
|
|
)
|
|
);
|
|
|
|
/// Prints an error-level message (level 3).
|
|
///
|
|
/// Use this level for error conditions.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_err`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_err`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_err
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_err!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! pr_err (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::ERR, false, $($arg)*)
|
|
)
|
|
);
|
|
|
|
/// Prints a warning-level message (level 4).
|
|
///
|
|
/// Use this level for warning conditions.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_warn`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_warn`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_warn
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_warn!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! pr_warn (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::WARNING, false, $($arg)*)
|
|
)
|
|
);
|
|
|
|
/// Prints a notice-level message (level 5).
|
|
///
|
|
/// Use this level for normal but significant conditions.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_notice`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_notice`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_notice
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_notice!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! pr_notice (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::NOTICE, false, $($arg)*)
|
|
)
|
|
);
|
|
|
|
/// Prints an info-level message (level 6).
|
|
///
|
|
/// Use this level for informational messages.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_info`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_info`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_info
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_info!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
#[doc(alias = "print")]
|
|
macro_rules! pr_info (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::INFO, false, $($arg)*)
|
|
)
|
|
);
|
|
|
|
/// Prints a debug-level message (level 7).
|
|
///
|
|
/// Use this level for debug messages.
|
|
///
|
|
/// Equivalent to the kernel's [`pr_debug`] macro, except that it doesn't support dynamic debug
|
|
/// yet.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_debug`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_debug
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// pr_debug!("hello {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
#[doc(alias = "print")]
|
|
macro_rules! pr_debug (
|
|
($($arg:tt)*) => (
|
|
if cfg!(debug_assertions) {
|
|
$crate::print_macro!($crate::print::format_strings::DEBUG, false, $($arg)*)
|
|
}
|
|
)
|
|
);
|
|
|
|
/// Continues a previous log message in the same line.
|
|
///
|
|
/// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
|
|
///
|
|
/// Equivalent to the kernel's [`pr_cont`] macro.
|
|
///
|
|
/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
|
|
/// `alloc::format!` for information about the formatting syntax.
|
|
///
|
|
/// [`pr_info!`]: crate::pr_info!
|
|
/// [`pr_cont`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_cont
|
|
/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// # use kernel::pr_cont;
|
|
/// pr_info!("hello");
|
|
/// pr_cont!(" {}\n", "there");
|
|
/// ```
|
|
#[macro_export]
|
|
macro_rules! pr_cont (
|
|
($($arg:tt)*) => (
|
|
$crate::print_macro!($crate::print::format_strings::CONT, true, $($arg)*)
|
|
)
|
|
);
|