On 02.08.24 11:31, Alice Ryhl wrote:
quoted hunk ↗ jump to hunk
diff --git a/rust/kernel/tracepoint.rs b/rust/kernel/tracepoint.rs
new file mode 100644
index 000000000000..69dafdb8bfe8
--- /dev/null
+++ b/rust/kernel/tracepoint.rs
@@ -0,0 +1,49 @@
+// 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.
I think we should mandate safety documentation for the function.
quoted hunk ↗ jump to hunk
+#[macro_export]
+macro_rules! declare_trace {
+ ($($(#[$attr:meta])* $pub:vis fn $name:ident($($argname:ident : $argtyp:ty),* $(,)?);)*) => {$(
Can you add an `unsafe` in front of `fn`, since this macro generates an
`unsafe` function? Otherwise I don't see how the SAFETY comment below is
correct.
---
Cheers,
Benno
+ $( #[$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::static_key::static_key_false!(
+ $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;
--
2.46.0.rc2.264.g509ed76dc8-goog