3 files changed, 49 insertions, 0 deletions

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 5541e75e140a..87d06c173ddc 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -189,6 +189,7 @@ static void prof_sysexit_disable_##sname(struct ftrace_event_call *event_call) \
                 .system                 = "syscalls",                   \
                 .event                  = &event_syscall_enter,         \
                 .raw_init               = init_enter_##sname,           \
+                .show_format            = ftrace_format_syscall,        \
                 .regfunc                = reg_event_syscall_enter,      \
                 .unregfunc              = unreg_event_syscall_enter,    \
                 .data                   = "sys"#sname,                  \
diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 3ab6dd18fa3a..0cb03625edd9 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -55,6 +55,8 @@ extern int reg_event_syscall_enter(void *ptr);
 extern void unreg_event_syscall_enter(void *ptr);
 extern int reg_event_syscall_exit(void *ptr);
 extern void unreg_event_syscall_exit(void *ptr);
+extern int
+ftrace_format_syscall(struct ftrace_event_call *call, struct trace_seq *s);
 enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags);
 enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags);
 #endif
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index f4eaec3d559a..9ee6386cf842 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -105,6 +105,52 @@ print_syscall_exit(struct trace_iterator *iter, int flags)
         return TRACE_TYPE_HANDLED;
 }
 
+int ftrace_format_syscall(struct ftrace_event_call *call, struct trace_seq *s)
+{
+        int i;
+        int nr;
+        int ret = 0;
+        struct syscall_metadata *entry;
+        int offset = sizeof(struct trace_entry);
+
+        nr = syscall_name_to_nr((char *)call->data);
+        entry = syscall_nr_to_meta(nr);
+
+        if (!entry)
+                return ret;
+
+        for (i = 0; i < entry->nb_args; i++) {
+                ret = trace_seq_printf(s, "\tfield:%s %s;", entry->types[i],
+                                        entry->args[i]);
+                if (!ret)
+                        return 0;
+                ret = trace_seq_printf(s, "\toffset:%d;\tsize:%lu;\n", offset,
+                                       sizeof(unsigned long));
+                if (!ret)
+                        return 0;
+                offset += sizeof(unsigned long);
+        }
+
+        trace_seq_printf(s, "\nprint fmt: \"");
+        for (i = 0; i < entry->nb_args; i++) {
+                ret = trace_seq_printf(s, "%s: 0x%%0%lulx%s", entry->args[i],
+                                        sizeof(unsigned long),
+                                        i == entry->nb_args - 1 ? "\", " : ", ");
+                if (!ret)
+                        return 0;
+        }
+
+        for (i = 0; i < entry->nb_args; i++) {
+                ret = trace_seq_printf(s, "((unsigned long)(REC->%s))%s",
+                                        entry->args[i],
+                                        i == entry->nb_args - 1 ? "\n" : ", ");
+                if (!ret)
+                        return 0;
+        }
+
+        return ret;
+}
+
 void ftrace_syscall_enter(struct pt_regs *regs, long id)
 {
         struct syscall_trace_enter *entry;