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authorJohannes Berg <johannes.berg@intel.com>2011-11-24 20:03:08 +0100
committerSteven Rostedt <rostedt@goodmis.org>2012-02-13 13:46:05 -0500
commit95100358491abaa2e9a5483811370059bbca4645 (patch)
tree4fc32c4bf2ef4416b4a914f5426f96ba58f29ec1
parentcdfb0d30e943f36c8a074a26c3d168a05bdbb372 (diff)
downloadop-kernel-dev-95100358491abaa2e9a5483811370059bbca4645.zip
op-kernel-dev-95100358491abaa2e9a5483811370059bbca4645.tar.gz
printk/tracing: Add console output tracing
Add a printk.console trace point to record any printk messages into the trace, regardless of the current console loglevel. This can help correlate (existing) printk debugging with other tracing. Link: http://lkml.kernel.org/r/1322161388.5366.54.camel@jlt3.sipsolutions.net Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rw-r--r--include/trace/events/printk.h41
-rw-r--r--kernel/printk.c5
2 files changed, 46 insertions, 0 deletions
diff --git a/include/trace/events/printk.h b/include/trace/events/printk.h
new file mode 100644
index 0000000..94ec79c
--- /dev/null
+++ b/include/trace/events/printk.h
@@ -0,0 +1,41 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM printk
+
+#if !defined(_TRACE_PRINTK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PRINTK_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT_CONDITION(console,
+ TP_PROTO(const char *log_buf, unsigned start, unsigned end,
+ unsigned log_buf_len),
+
+ TP_ARGS(log_buf, start, end, log_buf_len),
+
+ TP_CONDITION(start != end),
+
+ TP_STRUCT__entry(
+ __dynamic_array(char, msg, end - start + 1)
+ ),
+
+ TP_fast_assign(
+ if ((start & (log_buf_len - 1)) > (end & (log_buf_len - 1))) {
+ memcpy(__get_dynamic_array(msg),
+ log_buf + (start & (log_buf_len - 1)),
+ log_buf_len - (start & (log_buf_len - 1)));
+ memcpy((char *)__get_dynamic_array(msg) +
+ log_buf_len - (start & (log_buf_len - 1)),
+ log_buf, end & (log_buf_len - 1));
+ } else
+ memcpy(__get_dynamic_array(msg),
+ log_buf + (start & (log_buf_len - 1)),
+ end - start);
+ ((char *)__get_dynamic_array(msg))[end - start] = 0;
+ ),
+
+ TP_printk("%s", __get_str(msg))
+);
+#endif /* _TRACE_PRINTK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/printk.c b/kernel/printk.c
index 13c0a11..cb8a6bd 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -44,6 +44,9 @@
#include <asm/uaccess.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/printk.h>
+
/*
* Architectures can override it:
*/
@@ -542,6 +545,8 @@ MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
static void _call_console_drivers(unsigned start,
unsigned end, int msg_log_level)
{
+ trace_console(&LOG_BUF(0), start, end, log_buf_len);
+
if ((msg_log_level < console_loglevel || ignore_loglevel) &&
console_drivers && start != end) {
if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
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