1 files changed, 227 insertions, 0 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 65b9e863056b..b17a30350f06 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1320,6 +1320,224 @@ static struct file_operations ftrace_notrace_fops = {
         .release = ftrace_notrace_release,
 };
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+static DEFINE_MUTEX(graph_lock);
+
+int ftrace_graph_count;
+unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
+
+static void *
+g_next(struct seq_file *m, void *v, loff_t *pos)
+{
+        unsigned long *array = m->private;
+        int index = *pos;
+
+        (*pos)++;
+
+        if (index >= ftrace_graph_count)
+                return NULL;
+
+        return &array[index];
+}
+
+static void *g_start(struct seq_file *m, loff_t *pos)
+{
+        void *p = NULL;
+
+        mutex_lock(&graph_lock);
+
+        p = g_next(m, p, pos);
+
+        return p;
+}
+
+static void g_stop(struct seq_file *m, void *p)
+{
+        mutex_unlock(&graph_lock);
+}
+
+static int g_show(struct seq_file *m, void *v)
+{
+        unsigned long *ptr = v;
+        char str[KSYM_SYMBOL_LEN];
+
+        if (!ptr)
+                return 0;
+
+        kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
+
+        seq_printf(m, "%s\n", str);
+
+        return 0;
+}
+
+static struct seq_operations ftrace_graph_seq_ops = {
+        .start = g_start,
+        .next = g_next,
+        .stop = g_stop,
+        .show = g_show,
+};
+
+static int
+ftrace_graph_open(struct inode *inode, struct file *file)
+{
+        int ret = 0;
+
+        if (unlikely(ftrace_disabled))
+                return -ENODEV;
+
+        mutex_lock(&graph_lock);
+        if ((file->f_mode & FMODE_WRITE) &&
+            !(file->f_flags & O_APPEND)) {
+                ftrace_graph_count = 0;
+                memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
+        }
+
+        if (file->f_mode & FMODE_READ) {
+                ret = seq_open(file, &ftrace_graph_seq_ops);
+                if (!ret) {
+                        struct seq_file *m = file->private_data;
+                        m->private = ftrace_graph_funcs;
+                }
+        } else
+                file->private_data = ftrace_graph_funcs;
+        mutex_unlock(&graph_lock);
+
+        return ret;
+}
+
+static ssize_t
+ftrace_graph_read(struct file *file, char __user *ubuf,
+                       size_t cnt, loff_t *ppos)
+{
+        if (file->f_mode & FMODE_READ)
+                return seq_read(file, ubuf, cnt, ppos);
+        else
+                return -EPERM;
+}
+
+static int
+ftrace_set_func(unsigned long *array, int idx, char *buffer)
+{
+        char str[KSYM_SYMBOL_LEN];
+        struct dyn_ftrace *rec;
+        struct ftrace_page *pg;
+        int found = 0;
+        int i;
+
+        if (ftrace_disabled)
+                return -ENODEV;
+
+        /* should not be called from interrupt context */
+        spin_lock(&ftrace_lock);
+
+        for (pg = ftrace_pages_start; pg; pg = pg->next) {
+                for (i = 0; i < pg->index; i++) {
+                        rec = &pg->records[i];
+
+                        if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
+                                continue;
+
+                        kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
+                        if (strcmp(str, buffer) == 0) {
+                                found = 1;
+                                array[idx] = rec->ip;
+                                break;
+                        }
+                }
+        }
+        spin_unlock(&ftrace_lock);
+
+        return found ? 0 : -EINVAL;
+}
+
+static ssize_t
+ftrace_graph_write(struct file *file, const char __user *ubuf,
+                   size_t cnt, loff_t *ppos)
+{
+        unsigned char buffer[FTRACE_BUFF_MAX+1];
+        unsigned long *array;
+        size_t read = 0;
+        ssize_t ret;
+        int index = 0;
+        char ch;
+
+        if (!cnt || cnt < 0)
+                return 0;
+
+        mutex_lock(&graph_lock);
+
+        if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
+                ret = -EBUSY;
+                goto out;
+        }
+
+        if (file->f_mode & FMODE_READ) {
+                struct seq_file *m = file->private_data;
+                array = m->private;
+        } else
+                array = file->private_data;
+
+        ret = get_user(ch, ubuf++);
+        if (ret)
+                goto out;
+        read++;
+        cnt--;
+
+        /* skip white space */
+        while (cnt && isspace(ch)) {
+                ret = get_user(ch, ubuf++);
+                if (ret)
+                        goto out;
+                read++;
+                cnt--;
+        }
+
+        if (isspace(ch)) {
+                *ppos += read;
+                ret = read;
+                goto out;
+        }
+
+        while (cnt && !isspace(ch)) {
+                if (index < FTRACE_BUFF_MAX)
+                        buffer[index++] = ch;
+                else {
+                        ret = -EINVAL;
+                        goto out;
+                }
+                ret = get_user(ch, ubuf++);
+                if (ret)
+                        goto out;
+                read++;
+                cnt--;
+        }
+        buffer[index] = 0;
+
+        /* we allow only one at a time */
+        ret = ftrace_set_func(array, ftrace_graph_count, buffer);
+        if (ret)
+                goto out;
+
+        ftrace_graph_count++;
+
+        file->f_pos += read;
+
+        ret = read;
+ out:
+        mutex_unlock(&graph_lock);
+
+        return ret;
+}
+
+static const struct file_operations ftrace_graph_fops = {
+        .open = ftrace_graph_open,
+        .read = ftrace_graph_read,
+        .write = ftrace_graph_write,
+};
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
 {
         struct dentry *entry;
@@ -1347,6 +1565,15 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
                 pr_warning("Could not create debugfs "
                            "'set_ftrace_notrace' entry\n");
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
+                                    NULL,
+                                    &ftrace_graph_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'set_graph_function' entry\n");
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
         return 0;
 }