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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2024 Google LLC.
//! Logic for tracepoints.
/// Declare the Rust entry point for a tracepoint.
///
/// This macro generates an unsafe function that calls into C, and its safety requirements will be
/// whatever the relevant C code requires. To document these safety requirements, you may add
/// doc-comments when invoking the macro.
#[macro_export]
macro_rules! declare_trace {
($($(#[$attr:meta])* $pub:vis unsafe fn $name:ident($($argname:ident : $argtyp:ty),* $(,)?);)*) => {$(
$( #[$attr] )*
#[inline(always)]
$pub unsafe fn $name($($argname : $argtyp),*) {
#[cfg(CONFIG_TRACEPOINTS)]
{
// SAFETY: It's always okay to query the static key for a tracepoint.
let should_trace = unsafe {
$crate::macros::paste! {
$crate::jump_label::static_branch_unlikely!(
$crate::bindings::[< __tracepoint_ $name >],
$crate::bindings::tracepoint,
key
)
}
};
if should_trace {
$crate::macros::paste! {
// SAFETY: The caller guarantees that it is okay to call this tracepoint.
unsafe { $crate::bindings::[< rust_do_trace_ $name >]($($argname),*) };
}
}
}
#[cfg(not(CONFIG_TRACEPOINTS))]
{
// If tracepoints are disabled, insert a trivial use of each argument
// to avoid unused argument warnings.
$( let _unused = $argname; )*
}
}
)*}
}
pub use declare_trace;
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