rust: samples: add tracepoint to Rust sample

This updates the Rust printing sample to invoke a tracepoint. This
ensures that we have a user in-tree from the get-go even though the
patch is being merged before its real user.

Cc: Masami Hiramatsu <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Alex Gaynor <[email protected]>
Cc: Wedson Almeida Filho <[email protected]>
Cc: Gary Guo <[email protected]>
Cc: " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " <[email protected]>
Cc: Benno Lossin <[email protected]>
Cc: Andreas Hindborg <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: Uros Bizjak <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Oliver Upton <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Fuad Tabba <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Anup Patel <[email protected]>
Cc: Andrew Jones <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: Conor Dooley <[email protected]>
Cc: Samuel Holland <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Bibo Mao <[email protected]>
Cc: Tiezhu Yang <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Tianrui Zhao <[email protected]>
Link: https://lore.kernel.org/[email protected]
Reviewed-by: Boqun Feng <[email protected]>
Signed-off-by: Alice Ryhl <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

1 files changed, 18 insertions, 0 deletions

diff --git a/samples/rust/rust_print.rs b/samples/rust/rust_print.rs
index 6eabb0d79ea3..6d14b08cac1c 100644
--- a/samples/rust/rust_print.rs
+++ b/samples/rust/rust_print.rs
@@ -69,6 +69,8 @@ impl kernel::Module for RustPrint {
 
         arc_print()?;
 
+        trace::trace_rust_sample_loaded(42);
+
         Ok(RustPrint)
     }
 }
@@ -78,3 +80,19 @@ impl Drop for RustPrint {
         pr_info!("Rust printing macros sample (exit)\n");
     }
 }
+
+mod trace {
+    use core::ffi::c_int;
+
+    kernel::declare_trace! {
+        /// # Safety
+        ///
+        /// Always safe to call.
+        unsafe fn rust_sample_loaded(magic: c_int);
+    }
+
+    pub(crate) fn trace_rust_sample_loaded(magic: i32) {
+        // SAFETY: Always safe to call.
+        unsafe { rust_sample_loaded(magic as c_int) }
+    }
+}