1 files changed, 85 insertions, 3 deletions

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 15ef08d9add1..5a7d18c43634 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -27,6 +27,9 @@
 #undef __field
 #define __field(type, item)             type    item;
 
+#undef __string
+#define __string(item, src)             int     __str_loc_##item;
+
 #undef TP_STRUCT__entry
 #define TP_STRUCT__entry(args...) args
 
@@ -35,14 +38,53 @@
         struct ftrace_raw_##name {                              \
                 struct trace_entry      ent;                    \
                 tstruct                                         \
+                char                    __str_data[0];          \
         };                                                      \
         static struct ftrace_event_call event_##name
 
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 
+
 /*
  * Stage 2 of the trace events.
  *
+ * Include the following:
+ *
+ * struct ftrace_str_offsets_<call> {
+ *      int                             <str1>;
+ *      int                             <str2>;
+ *      [...]
+ * };
+ *
+ * The __string() macro will create each int <str>, this is to
+ * keep the offset of each string from the beggining of the event
+ * once we perform the strlen() of the src strings.
+ *
+ */
+
+#undef TRACE_FORMAT
+#define TRACE_FORMAT(call, proto, args, fmt)
+
+#undef __array
+#define __array(type, item, len)
+
+#undef __field
+#define __field(type, item);
+
+#undef __string
+#define __string(item, src)     int item;
+
+#undef TRACE_EVENT
+#define TRACE_EVENT(call, proto, args, tstruct, assign, print)          \
+        struct ftrace_str_offsets_##call {                              \
+                tstruct;                                                \
+        };
+
+#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
+
+/*
+ * Stage 3 of the trace events.
+ *
  * Override the macros in <trace/trace_events.h> to include the following:
  *
  * enum print_line_t
@@ -80,6 +122,9 @@
 #undef TP_printk
 #define TP_printk(fmt, args...) fmt "\n", args
 
+#undef __get_str
+#define __get_str(field)        (char *)__entry + __entry->__str_loc_##field
+
 #undef TRACE_EVENT
 #define TRACE_EVENT(call, proto, args, tstruct, assign, print)          \
 enum print_line_t                                                       \
@@ -146,6 +191,16 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags)	\
         if (!ret)                                                       \
                 return 0;
 
+#undef __string
+#define __string(item, src)                                                    \
+        ret = trace_seq_printf(s, "\tfield: __str_loc " #item ";\t"            \
+                               "offset:%u;tsize:%u;\n",                        \
+                               (unsigned int)offsetof(typeof(field),           \
+                                        __str_loc_##item),                     \
+                               (unsigned int)sizeof(field.__str_loc_##item));  \
+        if (!ret)                                                              \
+                return 0;
+
 #undef __entry
 #define __entry REC
 
@@ -189,6 +244,12 @@ ftrace_format_##call(struct trace_seq *s)				\
         if (ret)                                                        \
                 return ret;
 
+#undef __string
+#define __string(item, src)                                                    \
+        ret = trace_define_field(event_call, "__str_loc", #item,               \
+                                offsetof(typeof(field), __str_loc_##item),     \
+                                sizeof(field.__str_loc_##item));
+
 #undef TRACE_EVENT
 #define TRACE_EVENT(call, proto, args, tstruct, func, print)            \
 int                                                                     \
@@ -212,7 +273,7 @@ ftrace_define_fields_##call(void)					\
 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 
 /*
- * Stage 3 of the trace events.
+ * Stage 4 of the trace events.
  *
  * Override the macros in <trace/trace_events.h> to include the following:
  *
@@ -409,6 +470,23 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
 #undef __entry
 #define __entry entry
 
+#undef __field
+#define __field(type, item)
+
+#undef __array
+#define __array(type, item, len)
+
+#undef __string
+#define __string(item, src)                                                    \
+        __str_offsets.item = __str_size +                                      \
+                             offsetof(typeof(*entry), __str_data);             \
+        __str_size += strlen(src) + 1;
+
+#undef __assign_str
+#define __assign_str(dst, src)                                          \
+        __entry->__str_loc_##dst = __str_offsets.dst;                   \
+        strcpy(__get_str(dst), src);
+
 #undef TRACE_EVENT
 #define TRACE_EVENT(call, proto, args, tstruct, assign, print)          \
 _TRACE_PROFILE(call, PARAMS(proto), PARAMS(args))                       \
@@ -417,18 +495,22 @@ static struct ftrace_event_call event_##call;				\
                                                                         \
 static void ftrace_raw_event_##call(proto)                              \
 {                                                                       \
+        struct ftrace_str_offsets_##call __maybe_unused __str_offsets;  \
         struct ftrace_event_call *call = &event_##call;                 \
         struct ring_buffer_event *event;                                \
         struct ftrace_raw_##call *entry;                                \
         unsigned long irq_flags;                                        \
+        int __str_size = 0;                                             \
         int pc;                                                         \
                                                                         \
         local_save_flags(irq_flags);                                    \
         pc = preempt_count();                                           \
                                                                         \
+        tstruct;                                                        \
+                                                                        \
         event = trace_current_buffer_lock_reserve(event_##call.id,      \
-                                  sizeof(struct ftrace_raw_##call),     \
-                                  irq_flags, pc);                       \
+                                 sizeof(struct ftrace_raw_##call) + __str_size,\
+                                 irq_flags, pc);                        \
         if (!event)                                                     \
                 return;                                                 \
         entry   = ring_buffer_event_data(event);                        \