1 files changed, 74 insertions, 30 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index b5c09242683..4de3e57f723 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -38,15 +38,6 @@ struct fgraph_data {
 
 #define TRACE_GRAPH_INDENT	2
 
-/* Flag options */
-#define TRACE_GRAPH_PRINT_OVERRUN	0x1
-#define TRACE_GRAPH_PRINT_CPU		0x2
-#define TRACE_GRAPH_PRINT_OVERHEAD	0x4
-#define TRACE_GRAPH_PRINT_PROC		0x8
-#define TRACE_GRAPH_PRINT_DURATION	0x10
-#define TRACE_GRAPH_PRINT_ABS_TIME	0x20
-#define TRACE_GRAPH_PRINT_IRQS		0x40
-
 static unsigned int max_depth;
 
 static struct tracer_opt trace_opts[] = {
@@ -64,11 +55,13 @@ static struct tracer_opt trace_opts[] = {
 	{ TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
 	/* Display interrupts */
 	{ TRACER_OPT(funcgraph-irqs, TRACE_GRAPH_PRINT_IRQS) },
+	/* Display function name after trailing } */
+	{ TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
 	{ } /* Empty entry */
 };
 
 static struct tracer_flags tracer_flags = {
-	/* Don't display overruns and proc by default */
+	/* Don't display overruns, proc, or tail by default */
 	.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
 	       TRACE_GRAPH_PRINT_DURATION | TRACE_GRAPH_PRINT_IRQS,
 	.opts = trace_opts
@@ -82,9 +75,9 @@ static struct trace_array *graph_array;
  * to fill in space into DURATION column.
  */
 enum {
-	DURATION_FILL_FULL  = -1,
-	DURATION_FILL_START = -2,
-	DURATION_FILL_END   = -3,
+	FLAGS_FILL_FULL  = 1 << TRACE_GRAPH_PRINT_FILL_SHIFT,
+	FLAGS_FILL_START = 2 << TRACE_GRAPH_PRINT_FILL_SHIFT,
+	FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 };
 
 static enum print_line_t
@@ -114,16 +107,37 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 		return -EBUSY;
 	}
 
+	/*
+	 * The curr_ret_stack is an index to ftrace return stack of
+	 * current task.  Its value should be in [0, FTRACE_RETFUNC_
+	 * DEPTH) when the function graph tracer is used.  To support
+	 * filtering out specific functions, it makes the index
+	 * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
+	 * so when it sees a negative index the ftrace will ignore
+	 * the record.  And the index gets recovered when returning
+	 * from the filtered function by adding the FTRACE_NOTRACE_
+	 * DEPTH and then it'll continue to record functions normally.
+	 *
+	 * The curr_ret_stack is initialized to -1 and get increased
+	 * in this function.  So it can be less than -1 only if it was
+	 * filtered out via ftrace_graph_notrace_addr() which can be
+	 * set from set_graph_notrace file in debugfs by user.
+	 */
+	if (current->curr_ret_stack < -1)
+		return -EBUSY;
+
 	calltime = trace_clock_local();
 
 	index = ++current->curr_ret_stack;
+	if (ftrace_graph_notrace_addr(func))
+		current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
 	barrier();
 	current->ret_stack[index].ret = ret;
 	current->ret_stack[index].func = func;
 	current->ret_stack[index].calltime = calltime;
 	current->ret_stack[index].subtime = 0;
 	current->ret_stack[index].fp = frame_pointer;
-	*depth = index;
+	*depth = current->curr_ret_stack;
 
 	return 0;
 }
@@ -137,7 +151,17 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 
 	index = current->curr_ret_stack;
 
-	if (unlikely(index < 0)) {
+	/*
+	 * A negative index here means that it's just returned from a
+	 * notrace'd function.  Recover index to get an original
+	 * return address.  See ftrace_push_return_trace().
+	 *
+	 * TODO: Need to check whether the stack gets corrupted.
+	 */
+	if (index < 0)
+		index += FTRACE_NOTRACE_DEPTH;
+
+	if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
 		ftrace_graph_stop();
 		WARN_ON(1);
 		/* Might as well panic, otherwise we have no where to go */
@@ -193,6 +217,15 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 	trace.rettime = trace_clock_local();
 	barrier();
 	current->curr_ret_stack--;
+	/*
+	 * The curr_ret_stack can be less than -1 only if it was
+	 * filtered out and it's about to return from the function.
+	 * Recover the index and continue to trace normal functions.
+	 */
+	if (current->curr_ret_stack < -1) {
+		current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
+		return ret;
+	}
 
 	/*
 	 * The trace should run after decrementing the ret counter
@@ -230,7 +263,7 @@ int __trace_graph_entry(struct trace_array *tr,
 		return 0;
 	entry	= ring_buffer_event_data(event);
 	entry->graph_ent			= *trace;
-	if (!filter_current_check_discard(buffer, call, entry, event))
+	if (!call_filter_check_discard(call, entry, buffer, event))
 		__buffer_unlock_commit(buffer, event);
 
 	return 1;
@@ -259,10 +292,20 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
 
 	/* trace it when it is-nested-in or is a function enabled. */
 	if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
-	     ftrace_graph_ignore_irqs()) ||
+	     ftrace_graph_ignore_irqs()) || (trace->depth < 0) ||
 	    (max_depth && trace->depth >= max_depth))
 		return 0;
 
+	/*
+	 * Do not trace a function if it's filtered by set_graph_notrace.
+	 * Make the index of ret stack negative to indicate that it should
+	 * ignore further functions.  But it needs its own ret stack entry
+	 * to recover the original index in order to continue tracing after
+	 * returning from the function.
+	 */
+	if (ftrace_graph_notrace_addr(trace->func))
+		return 1;
+
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = per_cpu_ptr(tr->trace_buffer.data, cpu);
@@ -335,7 +378,7 @@ void __trace_graph_return(struct trace_array *tr,
 		return;
 	entry	= ring_buffer_event_data(event);
 	entry->ret				= *trace;
-	if (!filter_current_check_discard(buffer, call, entry, event))
+	if (!call_filter_check_discard(call, entry, buffer, event))
 		__buffer_unlock_commit(buffer, event);
 }
 
@@ -652,7 +695,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 	}
 
 	/* No overhead */
-	ret = print_graph_duration(DURATION_FILL_START, s, flags);
+	ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
 	if (ret != TRACE_TYPE_HANDLED)
 		return ret;
 
@@ -664,7 +707,7 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
-	ret = print_graph_duration(DURATION_FILL_END, s, flags);
+	ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
 	if (ret != TRACE_TYPE_HANDLED)
 		return ret;
 
@@ -729,14 +772,14 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s,
 			return TRACE_TYPE_HANDLED;
 
 	/* No real adata, just filling the column with spaces */
-	switch (duration) {
-	case DURATION_FILL_FULL:
+	switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
+	case FLAGS_FILL_FULL:
 		ret = trace_seq_puts(s, "              |  ");
 		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-	case DURATION_FILL_START:
+	case FLAGS_FILL_START:
 		ret = trace_seq_puts(s, "  ");
 		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
-	case DURATION_FILL_END:
+	case FLAGS_FILL_END:
 		ret = trace_seq_puts(s, " |");
 		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -852,7 +895,7 @@ print_graph_entry_nested(struct trace_iterator *iter,
 	}
 
 	/* No time */
-	ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
+	ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 	if (ret != TRACE_TYPE_HANDLED)
 		return ret;
 
@@ -1126,9 +1169,10 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 	 * If the return function does not have a matching entry,
 	 * then the entry was lost. Instead of just printing
 	 * the '}' and letting the user guess what function this
-	 * belongs to, write out the function name.
+	 * belongs to, write out the function name. Always do
+	 * that if the funcgraph-tail option is enabled.
 	 */
-	if (func_match) {
+	if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) {
 		ret = trace_seq_puts(s, "}\n");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
@@ -1172,7 +1216,7 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 		return TRACE_TYPE_PARTIAL_LINE;
 
 	/* No time */
-	ret = print_graph_duration(DURATION_FILL_FULL, s, flags);
+	ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 	if (ret != TRACE_TYPE_HANDLED)
 		return ret;
 
@@ -1426,7 +1470,8 @@ void graph_trace_close(struct trace_iterator *iter)
 	}
 }
 
-static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
+static int
+func_graph_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 {
 	if (bit == TRACE_GRAPH_PRINT_IRQS)
 		ftrace_graph_skip_irqs = !set;
@@ -1454,7 +1499,6 @@ static struct tracer graph_trace __tracer_data = {
 	.pipe_open	= graph_trace_open,
 	.close		= graph_trace_close,
 	.pipe_close	= graph_trace_close,
-	.wait_pipe	= poll_wait_pipe,
 	.init		= graph_trace_init,
 	.reset		= graph_trace_reset,
 	.print_line	= print_graph_function,