tracetool/ftrace: add Rust support

Signed-off-by: Tanish Desai <tanishdesai37@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20250929154938.594389-16-pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

3 files changed, 48 insertions, 2 deletions

diff --git a/scripts/tracetool/backend/ftrace.py b/scripts/tracetool/backend/ftrace.py
index 7ddd5d11a6..e03698a2ed 100644
--- a/scripts/tracetool/backend/ftrace.py
+++ b/scripts/tracetool/backend/ftrace.py
@@ -12,7 +12,7 @@ __maintainer__ = "Stefan Hajnoczi"
 __email__      = "stefanha@redhat.com"
 
 
-from tracetool import out
+from tracetool import out, expand_format_string
 
 
 PUBLIC = True
@@ -43,3 +43,9 @@ def generate_h(event, group):
 def generate_h_backend_dstate(event, group):
     out('    trace_event_get_state_dynamic_by_id(%(event_id)s) || \\',
         event_id="TRACE_" + event.name.upper())
+
+def generate_rs(event, group):
+    out('        let format_string = c"%(fmt)s";',
+        '        unsafe {bindings::ftrace_write(format_string.as_ptr() as *const c_char, %(args)s);}',
+        fmt=expand_format_string(event.fmt),
+        args=event.args.rust_call_varargs())
diff --git a/tests/tracetool/ftrace.rs b/tests/tracetool/ftrace.rs
new file mode 100644
index 0000000000..07b9259cf2
--- /dev/null
+++ b/tests/tracetool/ftrace.rs
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// This file is @generated by tracetool, do not edit.
+
+#[allow(unused_imports)]
+use std::ffi::c_char;
+#[allow(unused_imports)]
+use util::bindings;
+
+#[inline(always)]
+fn trace_event_state_is_enabled(dstate: u16) -> bool {
+    (unsafe { trace_events_enabled_count }) != 0 && dstate != 0
+}
+
+extern "C" {
+    static mut trace_events_enabled_count: u32;
+}
+extern "C" {
+    static mut _TRACE_TEST_BLAH_DSTATE: u16;
+    static mut _TRACE_TEST_WIBBLE_DSTATE: u16;
+}
+
+#[inline(always)]
+#[allow(dead_code)]
+pub fn trace_test_blah(_context: *mut (), _filename: &std::ffi::CStr)
+{
+    if trace_event_state_is_enabled(unsafe { _TRACE_TEST_BLAH_DSTATE}) {
+        let format_string = c"Blah context=%p filename=%s";
+        unsafe {bindings::ftrace_write(format_string.as_ptr() as *const c_char, _context /* as *mut () */, _filename.as_ptr());}
+    }
+}
+
+#[inline(always)]
+#[allow(dead_code)]
+pub fn trace_test_wibble(_context: *mut (), _value: std::ffi::c_int)
+{
+    if trace_event_state_is_enabled(unsafe { _TRACE_TEST_WIBBLE_DSTATE}) {
+        let format_string = c"Wibble context=%p value=%d";
+        unsafe {bindings::ftrace_write(format_string.as_ptr() as *const c_char, _context /* as *mut () */, _value /* as std::ffi::c_int */);}
+    }
+}
diff --git a/tests/tracetool/tracetool-test.py b/tests/tracetool/tracetool-test.py
index f58f3b795e..3341fb18f9 100755
--- a/tests/tracetool/tracetool-test.py
+++ b/tests/tracetool/tracetool-test.py
@@ -14,7 +14,7 @@ def get_formats(backend):
         "c",
         "h",
     ]
-    if backend in {"log", "simple"}:
+    if backend in {"ftrace", "log", "simple"}:
         formats += ["rs"]
     if backend == "dtrace":
         formats += [