uprobes/tracing: Make register_uprobe_event() paths uretprobe-friendly

Change uprobe_event_define_fields(), and __set_print_fmt() to check
is_ret_probe() and use the appropriate format/fields.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Anton Arapov <anton@redhat.com>

1 files changed, 15 insertions, 4 deletions

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 0ed99a27d122..457576215b3a 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -628,8 +628,14 @@ static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
         struct uprobe_trace_entry_head field;
         struct trace_uprobe *tu = event_call->data;
 
-        DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
-        size = SIZEOF_TRACE_ENTRY(false);
+        if (is_ret_probe(tu)) {
+                DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
+                DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
+                size = SIZEOF_TRACE_ENTRY(true);
+        } else {
+                DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
+                size = SIZEOF_TRACE_ENTRY(false);
+        }
         /* Set argument names as fields */
         for (i = 0; i < tu->nr_args; i++) {
                 ret = trace_define_field(event_call, tu->args[i].type->fmttype,
@@ -652,8 +658,13 @@ static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
         int i;
         int pos = 0;
 
-        fmt = "(%lx)";
-        arg = "REC->" FIELD_STRING_IP;
+        if (is_ret_probe(tu)) {
+                fmt = "(%lx <- %lx)";
+                arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+        } else {
+                fmt = "(%lx)";
+                arg = "REC->" FIELD_STRING_IP;
+        }
 
         /* When len=0, we just calculate the needed length */