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Commit 0f4fc29d authored by Steven Rostedt's avatar Steven Rostedt Committed by Frederic Weisbecker
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tracing: add __print_symbolic to trace events 



This patch adds __print_symbolic which is similar to __print_flags but
works for an enumeration type instead. That is, there is only a one to one
mapping between the values and the symbols. When a match is made, then
it is printed, otherwise the hex value is outputed.

[ Impact: add interface for showing symbol names in events ]

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 62ba180e

include/linux/ftrace_event.h

+3 −0
Original line number Diff line number Diff line
@@ -20,6 +20,9 @@ const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim, 
				   unsigned long flags,

				   const struct trace_print_flags *flag_array);



const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,

				     const struct trace_print_flags *symbol_array);



/*

 * The trace entry - the most basic unit of tracing. This is what

 * is printed in the end as a single line in the trace output, such as:

include/trace/ftrace.h

+8 −0
Original line number Diff line number Diff line
@@ -130,6 +130,14 @@ 
		ftrace_print_flags_seq(p, delim, flag, flags);		\

	})



#undef __print_symbolic

#define __print_symbolic(value, symbol_array...)			\

	({								\

		static const struct trace_print_flags symbols[] =	\

			{ symbol_array, { -1, NULL }};			\

		ftrace_print_symbols_seq(p, value, symbols);		\

	})



#undef TRACE_EVENT

#define TRACE_EVENT(call, proto, args, tstruct, assign, print)		\

enum print_line_t							\

kernel/trace/trace_output.c

+25 −0
Original line number Diff line number Diff line
@@ -251,6 +251,31 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim, 
	return p->buffer;

}



const char *

ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,

			 const struct trace_print_flags *symbol_array)

{

	int i;



	trace_seq_init(p);



	for (i = 0;  symbol_array[i].name; i++) {



		if (val != symbol_array[i].mask)

			continue;



		trace_seq_puts(p, symbol_array[i].name);

		break;

	}



	if (!p->len)

		trace_seq_printf(p, "0x%lx", val);

		

	trace_seq_putc(p, 0);



	return p->buffer;

}



#ifdef CONFIG_KRETPROBES

static inline const char *kretprobed(const char *name)

{