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