tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk()

[pandora-kernel.git] / kernel / trace / trace_printk.c

diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
new file mode 100644 (file)
index 0000000..a50aea2
--- /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);