2 files changed, 115 insertions, 1 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 55e1f7f0db12..593debefc4e9 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -472,11 +472,11 @@ extern void trace_find_cmdline(int pid, char comm[]);
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 extern unsigned long ftrace_update_tot_cnt;
+#endif
 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
 extern int DYN_FTRACE_TEST_NAME(void);
 #define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2
 extern int DYN_FTRACE_TEST_NAME2(void);
-#endif
 
 extern int ring_buffer_expanded;
 extern bool tracing_selftest_disabled;
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 86422f91dbe1..1003a4d5eb25 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -543,6 +543,116 @@ out:
 # define trace_selftest_function_recursion() ({ 0; })
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+static enum {
+        TRACE_SELFTEST_REGS_START,
+        TRACE_SELFTEST_REGS_FOUND,
+        TRACE_SELFTEST_REGS_NOT_FOUND,
+} trace_selftest_regs_stat;
+
+static void trace_selftest_test_regs_func(unsigned long ip,
+                                          unsigned long pip,
+                                          struct ftrace_ops *op,
+                                          struct pt_regs *pt_regs)
+{
+        if (pt_regs)
+                trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
+        else
+                trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;
+}
+
+static struct ftrace_ops test_regs_probe = {
+        .func           = trace_selftest_test_regs_func,
+        .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_SAVE_REGS,
+};
+
+static int
+trace_selftest_function_regs(void)
+{
+        int save_ftrace_enabled = ftrace_enabled;
+        int save_tracer_enabled = tracer_enabled;
+        char *func_name;
+        int len;
+        int ret;
+        int supported = 0;
+
+#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+        supported = 1;
+#endif
+
+        /* The previous test PASSED */
+        pr_cont("PASSED\n");
+        pr_info("Testing ftrace regs%s: ",
+                !supported ? "(no arch support)" : "");
+
+        /* enable tracing, and record the filter function */
+        ftrace_enabled = 1;
+        tracer_enabled = 1;
+
+        /* Handle PPC64 '.' name */
+        func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
+        len = strlen(func_name);
+
+        ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1);
+        /*
+         * If DYNAMIC_FTRACE is not set, then we just trace all functions.
+         * This test really doesn't care.
+         */
+        if (ret && ret != -ENODEV) {
+                pr_cont("*Could not set filter* ");
+                goto out;
+        }
+
+        ret = register_ftrace_function(&test_regs_probe);
+        /*
+         * Now if the arch does not support passing regs, then this should
+         * have failed.
+         */
+        if (!supported) {
+                if (!ret) {
+                        pr_cont("*registered save-regs without arch support* ");
+                        goto out;
+                }
+                test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED;
+                ret = register_ftrace_function(&test_regs_probe);
+        }
+        if (ret) {
+                pr_cont("*could not register callback* ");
+                goto out;
+        }
+
+
+        DYN_FTRACE_TEST_NAME();
+
+        unregister_ftrace_function(&test_regs_probe);
+
+        ret = -1;
+
+        switch (trace_selftest_regs_stat) {
+        case TRACE_SELFTEST_REGS_START:
+                pr_cont("*callback never called* ");
+                goto out;
+
+        case TRACE_SELFTEST_REGS_FOUND:
+                if (supported)
+                        break;
+                pr_cont("*callback received regs without arch support* ");
+                goto out;
+
+        case TRACE_SELFTEST_REGS_NOT_FOUND:
+                if (!supported)
+                        break;
+                pr_cont("*callback received NULL regs* ");
+                goto out;
+        }
+
+        ret = 0;
+out:
+        ftrace_enabled = save_ftrace_enabled;
+        tracer_enabled = save_tracer_enabled;
+
+        return ret;
+}
+
 /*
  * Simple verification test of ftrace function tracer.
  * Enable ftrace, sleep 1/10 second, and then read the trace
@@ -592,6 +702,10 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
                 goto out;
 
         ret = trace_selftest_function_recursion();
+        if (ret)
+                goto out;
+
+        ret = trace_selftest_function_regs();
  out:
         ftrace_enabled = save_ftrace_enabled;
         tracer_enabled = save_tracer_enabled;