1 files changed, 138 insertions, 0 deletions
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
new file mode 100644
index 000000000000..a50aea22e929
--- /dev/null
+++ b/kernel/trace/trace_printk.c
@@ -0,0 +1,138 @@
+/*
+ * trace binary printk
+ *
+ * Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com>
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/marker.h>
+#include <linux/uaccess.h>
+
+#include "trace.h"
+
+#ifdef CONFIG_MODULES
+
+/*
+ * modules trace_printk()'s formats are autosaved in struct trace_bprintk_fmt
+ * which are queued on trace_bprintk_fmt_list.
+ */
+static LIST_HEAD(trace_bprintk_fmt_list);
+
+/* serialize accesses to trace_bprintk_fmt_list */
+static DEFINE_MUTEX(btrace_mutex);
+
+struct trace_bprintk_fmt {
+	struct list_head list;
+	char fmt[0];
+};
+
+static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
+{
+	struct trace_bprintk_fmt *pos;
+	list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
+		if (!strcmp(pos->fmt, fmt))
+			return pos;
+	}
+	return NULL;
+}
+
+static
+void hold_module_trace_bprintk_format(const char **start, const char **end)
+{
+	const char **iter;
+
+	mutex_lock(&btrace_mutex);
+	for (iter = start; iter < end; iter++) {
+		struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
+		if (tb_fmt) {
+			*iter = tb_fmt->fmt;
+			continue;
+		}
+
+		tb_fmt = kmalloc(offsetof(struct trace_bprintk_fmt, fmt)
+				+ strlen(*iter) + 1, GFP_KERNEL);
+		if (tb_fmt) {
+			list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list);
+			strcpy(tb_fmt->fmt, *iter);
+			*iter = tb_fmt->fmt;
+		} else
+			*iter = NULL;
+	}
+	mutex_unlock(&btrace_mutex);
+}
+
+static int module_trace_bprintk_format_notify(struct notifier_block *self,
+		unsigned long val, void *data)
+{
+	struct module *mod = data;
+	if (mod->num_trace_bprintk_fmt) {
+		const char **start = mod->trace_bprintk_fmt_start;
+		const char **end = start + mod->num_trace_bprintk_fmt;
+
+		if (val == MODULE_STATE_COMING)
+			hold_module_trace_bprintk_format(start, end);
+	}
+	return 0;
+}
+
+#else /* !CONFIG_MODULES */
+__init static int
+module_trace_bprintk_format_notify(struct notifier_block *self,
+		unsigned long val, void *data)
+{
+	return 0;
+}
+#endif /* CONFIG_MODULES */
+
+
+__initdata_or_module static
+struct notifier_block module_trace_bprintk_format_nb = {
+	.notifier_call = module_trace_bprintk_format_notify,
+};
+
+int __trace_printk(unsigned long ip, const char *fmt, ...)
+ {
+	int ret;
+	va_list ap;
+
+	if (unlikely(!fmt))
+		return 0;
+
+	if (!(trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	va_start(ap, fmt);
+	ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+	va_end(ap);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_printk);
+
+int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
+ {
+	if (unlikely(!fmt))
+		return 0;
+
+	if (!(trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+}
+EXPORT_SYMBOL_GPL(__ftrace_vprintk);
+
+
+static __init int init_trace_printk(void)
+{
+	return register_module_notifier(&module_trace_bprintk_format_nb);
+}
+
+early_initcall(init_trace_printk);