Messages in this thread Patch in this message | | | Subject | [PATCH] printk: add console output tracing | From | Johannes Berg <> | Date | Wed, 16 Nov 2011 22:25:19 +0100 |
| |
From: Johannes Berg <johannes.berg@intel.com>
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.
Signed-off-by: Johannes Berg <johannes.berg@intel.com> --- include/trace/events/printk.h | 44 ++++++++++++++++++++++++++++++++++++++++++ kernel/printk.c | 3 ++ kernel/trace/Makefile | 1 kernel/trace/printk-trace.c | 14 +++++++++++++ 4 files changed, 62 insertions(+)
--- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ b/include/trace/events/printk.h 2011-11-16 22:06:43.000000000 +0100 @@ -0,0 +1,44 @@ +#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 + log_buf_len) & + (log_buf_len - 1)) + 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 + log_buf_len) & (log_buf_len - 1)); + ((char *)__get_dynamic_array(msg))[(end - start + log_buf_len) & + (log_buf_len - 1)] = 0; + ), + + TP_printk("%s", __get_str(msg)) +); +#endif /* _TRACE_PRINTK_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> --- a/kernel/printk.c 2011-11-16 16:37:20.000000000 +0100 +++ b/kernel/printk.c 2011-11-16 21:47:20.000000000 +0100 @@ -41,6 +41,7 @@ #include <linux/cpu.h> #include <linux/notifier.h> #include <linux/rculist.h> +#include <trace/events/printk.h> #include <asm/uaccess.h> @@ -542,6 +543,8 @@ MODULE_PARM_DESC(ignore_loglevel, "ignor 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)) { --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ b/kernel/trace/printk-trace.c 2011-11-16 21:22:20.000000000 +0100 @@ -0,0 +1,14 @@ +/* + * printk trace points + * + * Copyright (C) 2011 Johannes Berg <johannes.berg@intel.com> + */ + +#include <linux/string.h> +#include <linux/types.h> +#include <linux/workqueue.h> +#include <linux/sched.h> +#include <linux/module.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/printk.h> --- a/kernel/trace/Makefile 2011-11-16 16:37:20.000000000 +0100 +++ b/kernel/trace/Makefile 2011-11-16 21:38:49.000000000 +0100 @@ -55,6 +55,7 @@ endif obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o obj-$(CONFIG_TRACEPOINTS) += power-traces.o +obj-$(CONFIG_TRACEPOINTS) += printk-trace.o ifeq ($(CONFIG_PM_RUNTIME),y) obj-$(CONFIG_TRACEPOINTS) += rpm-traces.o endif
| |