tracing: Add get_syscall_name()

Add a utility function to grab the syscall name from the syscall
metadata, given a syscall id.

Link: http://lkml.kernel.org/r/be26a8dfe3f15e16a837799f1c1e2b4d62742843.1449767187.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 16 insertions, 0 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index c10456e72106..0044b91d5469 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1394,8 +1394,13 @@ int perf_ftrace_event_register(struct trace_event_call *call,
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 void init_ftrace_syscalls(void);
+const char *get_syscall_name(int syscall);
 #else
 static inline void init_ftrace_syscalls(void) { }
+static inline const char *get_syscall_name(int syscall)
+{
+        return NULL;
+}
 #endif
 
 #ifdef CONFIG_EVENT_TRACING
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 0655afbea83f..50be5602217c 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -106,6 +106,17 @@ static struct syscall_metadata *syscall_nr_to_meta(int nr)
         return syscalls_metadata[nr];
 }
 
+const char *get_syscall_name(int syscall)
+{
+        struct syscall_metadata *entry;
+
+        entry = syscall_nr_to_meta(syscall);
+        if (!entry)
+                return NULL;
+
+        return entry->name;
+}
+
 static enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags,
                     struct trace_event *event)