ftrace: Allow other users of function tracing to use the output listing
The function tracer is set up to allow any other subsystem (like perf)
to use it. Ftrace already has a way to list what functions are enabled
by the global_ops. It would be very helpful to let other users of
the function tracer to be able to use the same code.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 31b9fd7..aa7559f 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -202,6 +202,14 @@
FTRACE_UPDATE_MAKE_NOP,
};
+enum {
+ FTRACE_ITER_FILTER = (1 << 0),
+ FTRACE_ITER_NOTRACE = (1 << 1),
+ FTRACE_ITER_PRINTALL = (1 << 2),
+ FTRACE_ITER_HASH = (1 << 3),
+ FTRACE_ITER_ENABLED = (1 << 4),
+};
+
void arch_ftrace_update_code(int command);
struct ftrace_rec_iter;
@@ -217,6 +225,15 @@
extern ftrace_func_t ftrace_trace_function;
+int ftrace_regex_open(struct ftrace_ops *ops, int flag,
+ struct inode *inode, struct file *file);
+ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
+ size_t cnt, loff_t *ppos);
+ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
+ size_t cnt, loff_t *ppos);
+loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int origin);
+int ftrace_regex_release(struct inode *inode, struct file *file);
+
/* defined in arch */
extern int ftrace_ip_converted(unsigned long ip);
extern int ftrace_dyn_arch_init(void *data);
@@ -311,6 +328,24 @@
{
return 0;
}
+
+/*
+ * Again users of functions that have ftrace_ops may not
+ * have them defined when ftrace is not enabled, but these
+ * functions may still be called. Use a macro instead of inline.
+ */
+#define ftrace_regex_open(ops, flag, inod, file) ({ -ENODEV; })
+
+static inline ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
+ size_t cnt, loff_t *ppos) { return -ENODEV; }
+static inline ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
+ size_t cnt, loff_t *ppos) { return -ENODEV; }
+static inline loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
+{
+ return -ENODEV;
+}
+static inline int
+ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
#endif /* CONFIG_DYNAMIC_FTRACE */
/* totally disable ftrace - can not re-enable after this */
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e1ee07f..5b105c5 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2134,14 +2134,6 @@
return 0;
}
-enum {
- FTRACE_ITER_FILTER = (1 << 0),
- FTRACE_ITER_NOTRACE = (1 << 1),
- FTRACE_ITER_PRINTALL = (1 << 2),
- FTRACE_ITER_HASH = (1 << 3),
- FTRACE_ITER_ENABLED = (1 << 4),
-};
-
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
struct ftrace_iterator {
@@ -2249,7 +2241,7 @@
t_next(struct seq_file *m, void *v, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
- struct ftrace_ops *ops = &global_ops;
+ struct ftrace_ops *ops = iter->ops;
struct dyn_ftrace *rec = NULL;
if (unlikely(ftrace_disabled))
@@ -2305,7 +2297,7 @@
static void *t_start(struct seq_file *m, loff_t *pos)
{
struct ftrace_iterator *iter = m->private;
- struct ftrace_ops *ops = &global_ops;
+ struct ftrace_ops *ops = iter->ops;
void *p = NULL;
loff_t l;
@@ -2414,6 +2406,7 @@
return -ENOMEM;
iter->pg = ftrace_pages_start;
+ iter->ops = &global_ops;
ret = seq_open(file, &show_ftrace_seq_ops);
if (!ret) {
@@ -2442,6 +2435,7 @@
iter->pg = ftrace_pages_start;
iter->flags = FTRACE_ITER_ENABLED;
+ iter->ops = &global_ops;
ret = seq_open(file, &show_ftrace_seq_ops);
if (!ret) {
@@ -2462,7 +2456,23 @@
mutex_unlock(&ftrace_lock);
}
-static int
+/**
+ * ftrace_regex_open - initialize function tracer filter files
+ * @ops: The ftrace_ops that hold the hash filters
+ * @flag: The type of filter to process
+ * @inode: The inode, usually passed in to your open routine
+ * @file: The file, usually passed in to your open routine
+ *
+ * ftrace_regex_open() initializes the filter files for the
+ * @ops. Depending on @flag it may process the filter hash or
+ * the notrace hash of @ops. With this called from the open
+ * routine, you can use ftrace_filter_write() for the write
+ * routine if @flag has FTRACE_ITER_FILTER set, or
+ * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
+ * ftrace_regex_lseek() should be used as the lseek routine, and
+ * release must call ftrace_regex_release().
+ */
+int
ftrace_regex_open(struct ftrace_ops *ops, int flag,
struct inode *inode, struct file *file)
{
@@ -2542,7 +2552,7 @@
inode, file);
}
-static loff_t
+loff_t
ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
{
loff_t ret;
@@ -3095,14 +3105,14 @@
return ret;
}
-static ssize_t
+ssize_t
ftrace_filter_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
}
-static ssize_t
+ssize_t
ftrace_notrace_write(struct file *file, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
@@ -3292,8 +3302,7 @@
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
}
-static int
-ftrace_regex_release(struct inode *inode, struct file *file)
+int ftrace_regex_release(struct inode *inode, struct file *file)
{
struct seq_file *m = (struct seq_file *)file->private_data;
struct ftrace_iterator *iter;