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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Joel Fernandes <joel@joelfernandes.org>,
	Andy Lutomirski <luto@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Namhyung Kim <namhyung@kernel.org>,
	"Frank Ch. Eigler" <fche@redhat.com>
Subject: [PATCH 12/16 v3] function_graph: Move set_graph_function tests to shadow stack global var
Date: Fri, 24 May 2019 23:16:45 -0400	[thread overview]
Message-ID: <20190525031747.042357741@goodmis.org> (raw)
In-Reply-To: 20190525031633.811342628@goodmis.org

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The use of the task->trace_recursion for the logic used for the
set_graph_funnction was a bit of an abuse of that variable. Now that there
exists global vars that are per stack for registered graph traces, use that
instead.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h                 | 37 +++++++++++++++++-----------
 kernel/trace/trace_functions_graph.c |  6 ++---
 kernel/trace/trace_irqsoff.c         |  4 +--
 kernel/trace/trace_sched_wakeup.c    |  4 +--
 4 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index c45932573317..4baa2887f66b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -567,9 +567,6 @@ enum {
  */
 	TRACE_IRQ_BIT,
 
-	/* Set if the function is in the set_graph_function file */
-	TRACE_GRAPH_BIT,
-
 	/*
 	 * In the very unlikely case that an interrupt came in
 	 * at a start of graph tracing, and we want to trace
@@ -583,7 +580,7 @@ enum {
 	 * that preempted a softirq start of a function that
 	 * preempted normal context!!!! Luckily, it can't be
 	 * greater than 3, so the next two bits are a mask
-	 * of what the depth is when we set TRACE_GRAPH_BIT
+	 * of what the depth is when we set TRACE_GRAPH_FL
 	 */
 
 	TRACE_GRAPH_DEPTH_START_BIT,
@@ -937,11 +934,16 @@ extern void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops
 extern int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops);
 extern void free_fgraph_ops(struct trace_array *tr);
 
+enum {
+	TRACE_GRAPH_FL		= 1,
+};
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 extern struct ftrace_hash *ftrace_graph_hash;
 extern struct ftrace_hash *ftrace_graph_notrace_hash;
 
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int
+ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace)
 {
 	unsigned long addr = trace->func;
 	int ret = 0;
@@ -954,12 +956,11 @@ static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
 	}
 
 	if (ftrace_lookup_ip(ftrace_graph_hash, addr)) {
-
 		/*
 		 * This needs to be cleared on the return functions
 		 * when the depth is zero.
 		 */
-		trace_recursion_set(TRACE_GRAPH_BIT);
+		*task_var |= TRACE_GRAPH_FL;
 		trace_recursion_set_depth(trace->depth);
 
 		/*
@@ -979,11 +980,14 @@ static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
 	return ret;
 }
 
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void
+ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret *trace)
 {
-	if (trace_recursion_test(TRACE_GRAPH_BIT) &&
+	unsigned long *task_var = fgraph_get_task_var(gops);
+
+	if ((*task_var & TRACE_GRAPH_FL) &&
 	    trace->depth == trace_recursion_depth())
-		trace_recursion_clear(TRACE_GRAPH_BIT);
+		*task_var &= ~TRACE_GRAPH_FL;
 }
 
 static inline int ftrace_graph_notrace_addr(unsigned long addr)
@@ -1000,7 +1004,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
 }
 
 #else
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace)
 {
 	return 1;
 }
@@ -1009,17 +1013,20 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
 {
 	return 0;
 }
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret *trace)
 { }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 extern unsigned int fgraph_max_depth;
 
-static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
+static inline bool
+ftrace_graph_ignore_func(struct fgraph_ops *gops, struct ftrace_graph_ent *trace)
 {
+	unsigned long *task_var = fgraph_get_task_var(gops);
+
 	/* trace it when it is-nested-in or is a function enabled. */
-	return !(trace_recursion_test(TRACE_GRAPH_BIT) ||
-		 ftrace_graph_addr(trace)) ||
+	return !((*task_var & TRACE_GRAPH_FL) ||
+		 ftrace_graph_addr(task_var, trace)) ||
 		(trace->depth < 0) ||
 		(fgraph_max_depth && trace->depth >= fgraph_max_depth);
 }
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 0434e6052650..054ec91e5086 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -148,7 +148,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace,
 	if (!ftrace_trace_task(tr))
 		return 0;
 
-	if (ftrace_graph_ignore_func(trace))
+	if (ftrace_graph_ignore_func(gops, trace))
 		return 0;
 
 	if (ftrace_graph_ignore_irqs())
@@ -246,7 +246,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
 	int cpu;
 	int pc;
 
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
 		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
@@ -268,7 +268,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
 				      struct fgraph_ops *gops)
 {
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
 		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 55c547f6e31d..7e31f0a2ef58 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -181,7 +181,7 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace,
 	int ret;
 	int pc;
 
-	if (ftrace_graph_ignore_func(trace))
+	if (ftrace_graph_ignore_func(gops, trace))
 		return 0;
 	/*
 	 * Do not trace a function if it's filtered by set_graph_notrace.
@@ -211,7 +211,7 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace,
 	unsigned long flags;
 	int pc;
 
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (!func_prolog_dec(tr, &data, &flags))
 		return;
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 9da1062a8181..a04e59f6f13f 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -120,7 +120,7 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace,
 	unsigned long flags;
 	int pc, ret = 0;
 
-	if (ftrace_graph_ignore_func(trace))
+	if (ftrace_graph_ignore_func(gops, trace))
 		return 0;
 	/*
 	 * Do not trace a function if it's filtered by set_graph_notrace.
@@ -151,7 +151,7 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace,
 	unsigned long flags;
 	int pc;
 
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (!func_prolog_preempt_disable(tr, &data, &pc))
 		return;
-- 
2.20.1



  parent reply	other threads:[~2019-05-25  3:18 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-25  3:16 [PATCH 00/16 v3] function_graph: Rewrite to allow multiple users Steven Rostedt
2019-05-25  3:16 ` [PATCH 01/16 v3] function_graph: Convert ret_stack to a series of longs Steven Rostedt
2019-05-28  9:50   ` Joel Fernandes
2019-05-28 12:58     ` Steven Rostedt
2019-05-28 17:46       ` Joel Fernandes
2019-05-25  3:16 ` [PATCH 02/16 v3] fgraph: Use BUILD_BUG_ON() to make sure we have structures divisible by long Steven Rostedt
2019-05-25  3:16 ` [PATCH 03/16 v3] fgraph: Have the current->ret_stack go down not up Steven Rostedt
2019-05-25  3:16 ` [PATCH 04/16 v3] function_graph: Add an array structure that will allow multiple callbacks Steven Rostedt
2019-05-25  3:16 ` [PATCH 05/16 v3] function_graph: Allow multiple users to attach to function graph Steven Rostedt
2019-05-25  3:16 ` [PATCH 06/16 v3] function_graph: Remove logic around ftrace_graph_entry and return Steven Rostedt
2019-05-25  3:16 ` [PATCH 07/16 v3] ftrace/function_graph: Pass fgraph_ops to function graph callbacks Steven Rostedt
2019-05-25  3:16 ` [PATCH 08/16 v3] ftrace: Allow function_graph tracer to be enabled in instances Steven Rostedt
2019-05-25  3:16 ` [PATCH 09/16 v3] ftrace: Allow ftrace startup flags exist without dynamic ftrace Steven Rostedt
2019-05-25  3:16 ` [PATCH 10/16 v3] function_graph: Have the instances use their own ftrace_ops for filtering Steven Rostedt
2019-05-25  3:16 ` [PATCH 11/16 v3] function_graph: Add "task variables" per task for fgraph_ops Steven Rostedt
2019-05-25  3:16 ` Steven Rostedt [this message]
2019-05-25  3:16 ` [PATCH 13/16 v3] function_graph: Move graph depth stored data to shadow stack global var Steven Rostedt
2019-05-25  3:16 ` [PATCH 14/16 v3] function_graph: Move graph notrace bit " Steven Rostedt
2019-05-25  3:16 ` [PATCH 15/16 v3] function_graph: Implement fgraph_reserve_data() and fgraph_retrieve_data() Steven Rostedt
2019-05-25  3:16 ` [PATCH 16/16 v3] function_graph: Add selftest for passing local variables Steven Rostedt

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