tracing: Add function probe to trigger a ftrace dump of current CPU trace

[~andy/linux] / kernel / trace / trace_functions.c

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index d7c8719734b8be2b8064736226768fdb58d7ae52..b863f93b30f35caae4239629ea56d05b58b38639 100644 (file)
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -297,6 +297,14 @@ ftrace_dump_probe(unsigned long ip, unsigned long parent_ip, void **data)
                ftrace_dump(DUMP_ALL);
 }
 
+/* Only dump the current CPU buffer. */
+static void
+ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip, void **data)
+{
+       if (update_count(data))
+               ftrace_dump(DUMP_ORIG);
+}
+
 static int
 ftrace_probe_print(const char *name, struct seq_file *m,
                   unsigned long ip, void *data)
@@ -341,6 +349,13 @@ ftrace_dump_print(struct seq_file *m, unsigned long ip,
        return ftrace_probe_print("dump", m, ip, data);
 }
 
+static int
+ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
+                       struct ftrace_probe_ops *ops, void *data)
+{
+       return ftrace_probe_print("cpudump", m, ip, data);
+}
+
 static struct ftrace_probe_ops traceon_count_probe_ops = {
        .func                   = ftrace_traceon_count,
        .print                  = ftrace_traceon_print,
@@ -361,6 +376,11 @@ static struct ftrace_probe_ops dump_probe_ops = {
        .print                  = ftrace_dump_print,
 };
 
+static struct ftrace_probe_ops cpudump_probe_ops = {
+       .func                   = ftrace_cpudump_probe,
+       .print                  = ftrace_cpudump_print,
+};
+
 static struct ftrace_probe_ops traceon_probe_ops = {
        .func                   = ftrace_traceon,
        .print                  = ftrace_traceon_print,
@@ -457,6 +477,19 @@ ftrace_dump_callback(struct ftrace_hash *hash,
                                           "1", enable);
 }
 
+static int
+ftrace_cpudump_callback(struct ftrace_hash *hash,
+                          char *glob, char *cmd, char *param, int enable)
+{
+       struct ftrace_probe_ops *ops;
+
+       ops = &cpudump_probe_ops;
+
+       /* Only dump once. */
+       return ftrace_trace_probe_callback(ops, hash, glob, cmd,
+                                          "1", enable);
+}
+
 static struct ftrace_func_command ftrace_traceon_cmd = {
        .name                   = "traceon",
        .func                   = ftrace_trace_onoff_callback,
@@ -477,6 +510,11 @@ static struct ftrace_func_command ftrace_dump_cmd = {
        .func                   = ftrace_dump_callback,
 };
 
+static struct ftrace_func_command ftrace_cpudump_cmd = {
+       .name                   = "cpudump",
+       .func                   = ftrace_cpudump_callback,
+};
+
 static int __init init_func_cmd_traceon(void)
 {
        int ret;
@@ -497,8 +535,14 @@ static int __init init_func_cmd_traceon(void)
        if (ret)
                goto out_free_stacktrace;
 
+       ret = register_ftrace_command(&ftrace_cpudump_cmd);
+       if (ret)
+               goto out_free_dump;
+
        return 0;
 
+ out_free_dump:
+       unregister_ftrace_command(&ftrace_dump_cmd);
  out_free_stacktrace:
        unregister_ftrace_command(&ftrace_stacktrace_cmd);
  out_free_traceon: