[PATCH v3 2/3] selftest/ftrace: Move kprobe selftest function to separate compile unit

[Masami Hiramatsu]

From: Francis Deslauriers <francis.deslauriers@xxxxxxxxxxxx>

Move selftest function to its own compile unit so it can be compiled
with the ftrace cflags (CC_FLAGS_FTRACE) allowing it to be probed
during the ftrace startup tests.

Signed-off-by: Francis Deslauriers <francis.deslauriers@xxxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 kernel/trace/Makefile                |    5 +++++
 kernel/trace/trace_kprobe.c          |   12 +-----------
 kernel/trace/trace_kprobe_selftest.c |   10 ++++++++++
 kernel/trace/trace_kprobe_selftest.h |    7 +++++++
 4 files changed, 23 insertions(+), 11 deletions(-)
 create mode 100644 kernel/trace/trace_kprobe_selftest.c
 create mode 100644 kernel/trace/trace_kprobe_selftest.h

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index e2538c7638d4..e38771eccb2f 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -13,6 +13,11 @@ obj-y += trace_selftest_dynamic.o
 endif
 endif
 
+ifdef CONFIG_FTRACE_STARTUP_TEST
+CFLAGS_trace_kprobe_selftest.o = $(CC_FLAGS_FTRACE)
+obj-$(CONFIG_KPROBE_EVENTS) += trace_kprobe_selftest.o
+endif
+
 # If unlikely tracing is enabled, do not trace these files
 ifdef CONFIG_TRACING_BRANCHES
 KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 2bf75af92f16..88b49396ba08 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -23,6 +23,7 @@
 #include <linux/rculist.h>
 #include <linux/error-injection.h>
 
+#include "trace_kprobe_selftest.h"
 #include "trace_probe.h"
 
 #define KPROBE_EVENT_SYSTEM "kprobes"
@@ -1578,17 +1579,6 @@ fs_initcall(init_kprobe_trace);
 
 
 #ifdef CONFIG_FTRACE_STARTUP_TEST
-/*
- * The "__used" keeps gcc from removing the function symbol
- * from the kallsyms table. 'noinline' makes sure that there
- * isn't an inlined version used by the test method below
- */
-static __used __init noinline int
-kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
-{
-	return a1 + a2 + a3 + a4 + a5 + a6;
-}
-
 static __init struct trace_event_file *
 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
 {
diff --git a/kernel/trace/trace_kprobe_selftest.c b/kernel/trace/trace_kprobe_selftest.c
new file mode 100644
index 000000000000..16548ee4c8c6
--- /dev/null
+++ b/kernel/trace/trace_kprobe_selftest.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Function used during the kprobe self test. This function is in a separate
+ * compile unit so it can be compile with CC_FLAGS_FTRACE to ensure that it
+ * can be probed by the selftests.
+ */
+int kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
+{
+	return a1 + a2 + a3 + a4 + a5 + a6;
+}
diff --git a/kernel/trace/trace_kprobe_selftest.h b/kernel/trace/trace_kprobe_selftest.h
new file mode 100644
index 000000000000..4e10ec41c013
--- /dev/null
+++ b/kernel/trace/trace_kprobe_selftest.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Function used during the kprobe self test. This function is in a separate
+ * compile unit so it can be compile with CC_FLAGS_FTRACE to ensure that it
+ * can be probed by the selftests.
+ */
+int kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6);