Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace

include/trace/sched_event_types.h

@@ -71,10 +71,15 @@ TRACE_EVENT_FORMAT(sched_switch,
 	TRACE_STRUCT(
 		TRACE_FIELD(pid_t, prev_pid, prev->pid)
 		TRACE_FIELD(int, prev_prio, prev->prio)
+		TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN],
+				    next_comm,
+				    TPCMD(memcpy(TRACE_ENTRY->next_comm,
+						 next->comm,
+						 TASK_COMM_LEN)))
 		TRACE_FIELD(pid_t, next_pid, next->pid)
 		TRACE_FIELD(int, next_prio, next->prio)
 	),
-	TPRAWFMT("prev %d:%d ==> next %d:%d")
+	TPRAWFMT("prev %d:%d ==> next %s:%d:%d")
 	);
 
 TRACE_EVENT_FORMAT(sched_migrate_task,

kernel/trace/trace.c

@@ -342,13 +342,6 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 	tracing_record_cmdline(tsk);
 }
 
-static void
-trace_seq_reset(struct trace_seq *s)
-{
-	s->len = 0;
-	s->readpos = 0;
-}
-
 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
 {
 	int len;
@@ -395,7 +388,7 @@ trace_print_seq(struct seq_file *m, struct trace_seq *s)
 	s->buffer[len] = 0;
 	seq_puts(m, s->buffer);
 
-	trace_seq_reset(s);
+	trace_seq_init(s);
 }
 
 /**
@@ -2620,7 +2613,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
 	if (sret != -EBUSY)
 		return sret;
 
-	trace_seq_reset(&iter->seq);
+	trace_seq_init(&iter->seq);
 
 	/* copy the tracer to avoid using a global lock all around */
 	mutex_lock(&trace_types_lock);
@@ -2682,7 +2675,7 @@ waitagain:
 	/* Now copy what we have to the user */
 	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
 	if (iter->seq.readpos >= iter->seq.len)
-		trace_seq_reset(&iter->seq);
+		trace_seq_init(&iter->seq);
 
 	/*
 	 * If there was nothing to send to user, inspite of consuming trace
@@ -2819,7 +2812,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
 		partial[i].offset = 0;
 		partial[i].len = iter->seq.len;
 
-		trace_seq_reset(&iter->seq);
+		trace_seq_init(&iter->seq);
 	}
 
 	mutex_unlock(&iter->mutex);
@@ -3631,7 +3624,7 @@ trace_printk_seq(struct trace_seq *s)
 
 	printk(KERN_TRACE "%s", s->buffer);
 
-	trace_seq_reset(s);
+	trace_seq_init(s);
 }
 
 void ftrace_dump(void)

kernel/trace/trace.h

@@ -395,6 +395,14 @@ struct trace_seq {
 	unsigned int		readpos;
 };
 
+static inline void
+trace_seq_init(struct trace_seq *s)
+{
+	s->len = 0;
+	s->readpos = 0;
+}
+
+
 #define TRACE_PIPE_ALL_CPU	-1
 
 /*
@@ -746,6 +754,7 @@ struct ftrace_event_call {
 	int		(*raw_init)(void);
 	int		(*raw_reg)(void);
 	void		(*raw_unreg)(void);
+	int		(*show_format)(struct trace_seq *s);
 };
 
 void event_trace_printk(unsigned long ip, const char *fmt, ...);

kernel/trace/trace_events.c

@@ -3,6 +3,9 @@
  *
  * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
  *
+ *  - Added format output of fields of the trace point.
+ *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
+ *
  */
 
 #include <linux/debugfs.h>
@@ -10,10 +13,12 @@
 #include <linux/module.h>
 #include <linux/ctype.h>
 
-#include "trace.h"
+#include "trace_output.h"
 
 #define TRACE_SYSTEM "TRACE_SYSTEM"
 
+static DEFINE_MUTEX(event_mutex);
+
 #define events_for_each(event)						\
 	for (event = __start_ftrace_events;				\
 	     (unsigned long)event < (unsigned long)__stop_ftrace_events; \
@@ -104,6 +109,7 @@ static int ftrace_set_clr_event(char *buf, int set)
 			event = NULL;
 	}
 
+	mutex_lock(&event_mutex);
 	events_for_each(call) {
 
 		if (!call->name)
@@ -124,6 +130,8 @@ static int ftrace_set_clr_event(char *buf, int set)
 
 		ret = 0;
 	}
+	mutex_unlock(&event_mutex);
+
 	return ret;
 }
 
@@ -324,7 +332,9 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
 	switch (val) {
 	case 0:
 	case 1:
+		mutex_lock(&event_mutex);
 		ftrace_event_enable_disable(call, val);
+		mutex_unlock(&event_mutex);
 		break;
 
 	default:
@@ -437,6 +447,71 @@ event_available_types_read(struct file *filp, char __user *ubuf, size_t cnt,
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
+#undef FIELD
+#define FIELD(type, name) \
+	#type, #name, offsetof(typeof(field), name), sizeof(field.name)
+
+static int trace_write_header(struct trace_seq *s)
+{
+	struct trace_entry field;
+
+	/* struct trace_entry */
+	return trace_seq_printf(s,
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\n",
+				FIELD(unsigned char, type),
+				FIELD(unsigned char, flags),
+				FIELD(unsigned char, preempt_count),
+				FIELD(int, pid),
+				FIELD(int, tgid));
+}
+static ssize_t
+event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
+		  loff_t *ppos)
+{
+	struct ftrace_event_call *call = filp->private_data;
+	struct trace_seq *s;
+	char *buf;
+	int r;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	trace_seq_init(s);
+
+	if (*ppos)
+		return 0;
+
+	/* If any of the first writes fail, so will the show_format. */
+
+	trace_seq_printf(s, "name: %s\n", call->name);
+	trace_seq_printf(s, "ID: %d\n", call->id);
+	trace_seq_printf(s, "format:\n");
+	trace_write_header(s);
+
+	r = call->show_format(s);
+	if (!r) {
+		/*
+		 * ug!  The format output is bigger than a PAGE!!
+		 */
+		buf = "FORMAT TOO BIG\n";
+		r = simple_read_from_buffer(ubuf, cnt, ppos,
+					      buf, strlen(buf));
+		goto out;
+	}
+
+	r = simple_read_from_buffer(ubuf, cnt, ppos,
+				    s->buffer, s->len);
+ out:
+	kfree(s);
+	return r;
+}
+
 static const struct seq_operations show_event_seq_ops = {
 	.start = t_start,
 	.next = t_next,
@@ -483,6 +558,11 @@ static const struct file_operations ftrace_available_types_fops = {
 	.read = event_available_types_read,
 };
 
+static const struct file_operations ftrace_event_format_fops = {
+	.open = tracing_open_generic,
+	.read = event_format_read,
+};
+
 static struct dentry *event_trace_events_dir(void)
 {
 	static struct dentry *d_tracer;
@@ -595,7 +675,17 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
 				    &ftrace_available_types_fops);
 	if (!entry)
 		pr_warning("Could not create debugfs "
-			   "'%s/type' available_types\n", call->name);
+			   "'%s/available_types' entry\n", call->name);
+
+	/* A trace may not want to export its format */
+	if (!call->show_format)
+		return 0;
+
+	entry = debugfs_create_file("format", 0444, call->dir, call,
+				    &ftrace_event_format_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'%s/format' entry\n", call->name);
 
 	return 0;
 }

kernel/trace/trace_events_stage_1.h

@@ -30,5 +30,7 @@
 
 #define TRACE_FIELD(type, item, assign) \
 	type item;
+#define TRACE_FIELD_SPECIAL(type_item, item, cmd) \
+	type_item;
 
 #include <trace/trace_event_types.h>

kernel/trace/trace_events_stage_2.h

@@ -39,6 +39,10 @@
 #define TRACE_FIELD(type, item, assign) \
 	field->item,
 
+#undef TRACE_FIELD_SPECIAL
+#define TRACE_FIELD_SPECIAL(type_item, item, cmd) \
+	field->item,
+
 
 #undef TPRAWFMT
 #define TPRAWFMT(args...)	args
@@ -70,3 +74,57 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags)	\
 }
 
 #include <trace/trace_event_types.h>
+
+/*
+ * Setup the showing format of trace point.
+ *
+ * int
+ * ftrace_format_##call(struct trace_seq *s)
+ * {
+ * 	struct ftrace_raw_##call field;
+ * 	int ret;
+ *
+ * 	ret = trace_seq_printf(s, #type " " #item ";"
+ * 			       " size:%d; offset:%d;\n",
+ * 			       sizeof(field.type),
+ * 			       offsetof(struct ftrace_raw_##call,
+ * 					item));
+ *
+ * }
+ */
+
+#undef TRACE_FIELD
+#define TRACE_FIELD(type, item, assign)					\
+	ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t"	\
+			       "offset:%lu;\tsize:%lu;\n",		\
+			       offsetof(typeof(field), item),		\
+			       sizeof(field.item));			\
+	if (!ret)							\
+		return 0;
+
+
+#undef TRACE_FIELD_SPECIAL
+#define TRACE_FIELD_SPECIAL(type_item, item, cmd)			\
+	ret = trace_seq_printf(s, "\tfield special:" #type_item ";\t"	\
+			       "offset:%lu;\tsize:%lu;\n",		\
+			       offsetof(typeof(field), item),		\
+			       sizeof(field.item));			\
+	if (!ret)							\
+		return 0;
+
+#undef TRACE_EVENT_FORMAT
+#define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt)	\
+int									\
+ftrace_format_##call(struct trace_seq *s)				\
+{									\
+	struct ftrace_raw_##call field;					\
+	int ret;							\
+									\
+	tstruct;							\
+									\
+	trace_seq_printf(s, "\nprint fmt: \"%s\"\n", tpfmt);		\
+									\
+	return ret;							\
+}
+
+#include <trace/trace_event_types.h>

kernel/trace/trace_events_stage_3.h

@@ -101,6 +101,7 @@
  * 	.raw_init		= ftrace_raw_init_event_<call>,
  * 	.raw_reg		= ftrace_raw_reg_event_<call>,
  * 	.raw_unreg		= ftrace_raw_unreg_event_<call>,
+ *	.show_format		= ftrace_format_<call>,
  * }
  *
  */
@@ -147,6 +148,20 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
 #define TRACE_FIELD(type, item, assign)\
 	entry->item = assign;
 
+#undef TRACE_FIELD
+#define TRACE_FIELD(type, item, assign)\
+	entry->item = assign;
+
+#undef TPCMD
+#define TPCMD(cmd...)	cmd
+
+#undef TRACE_ENTRY
+#define TRACE_ENTRY	entry
+
+#undef TRACE_FIELD_SPECIAL
+#define TRACE_FIELD_SPECIAL(type_item, item, cmd) \
+	cmd;
+
 #undef TRACE_EVENT_FORMAT
 #define TRACE_EVENT_FORMAT(call, proto, args, fmt, tstruct, tpfmt)	\
 _TRACE_FORMAT(call, PARAMS(proto), PARAMS(args), PARAMS(fmt))		\
@@ -216,4 +231,5 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
 	.raw_init		= ftrace_raw_init_event_##call,		\
 	.raw_reg		= ftrace_raw_reg_event_##call,		\
 	.raw_unreg		= ftrace_raw_unreg_event_##call,	\
+	.show_format		= ftrace_format_##call,			\
 }