linux-kernel - [for-next][PATCH 07/24] sh: ftrace: Use ftrace_graph_get_ret_stack() instead of curr_ret

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Message-Id: <20181221175656.345267788@goodmis.org>
Date:   Fri, 21 Dec 2018 12:56:25 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     linux-kernel@...r.kernel.org
Cc:     Ingo Molnar <mingo@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        linux-sh@...r.kernel.org,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>
Subject: [for-next][PATCH 07/24] sh: ftrace: Use ftrace_graph_get_ret_stack() instead of
 curr_ret_stack

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

The structure of the ret_stack array on the task struct is going to
change, and accessing it directly via the curr_ret_stack index will no
longer give the ret_stack entry that holds the return address. To access
that, architectures must now use ftrace_graph_get_ret_stack() to get the
associated ret_stack that matches the saved return address.

Cc: linux-sh@...r.kernel.org
Cc: Yoshinori Sato <ysato@...rs.sourceforge.jp>
Cc: Rich Felker <dalias@...c.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
 arch/sh/kernel/dumpstack.c | 11 +++++++----
 arch/sh/kernel/dwarf.c     |  9 +++++----
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c
index b564b1eae4ae..2c2e151bf39e 100644
--- a/arch/sh/kernel/dumpstack.c
+++ b/arch/sh/kernel/dumpstack.c
@@ -59,17 +59,20 @@ print_ftrace_graph_addr(unsigned long addr, void *data,
 			struct thread_info *tinfo, int *graph)
 {
 	struct task_struct *task = tinfo->task;
+	struct ftrace_ret_stack *ret_stack;
 	unsigned long ret_addr;
-	int index = task->curr_ret_stack;
 
 	if (addr != (unsigned long)return_to_handler)
 		return;
 
-	if (!task->ret_stack || index < *graph)
+	if (!task->ret_stack)
 		return;
 
-	index -= *graph;
-	ret_addr = task->ret_stack[index].ret;
+	ret_stack = ftrace_graph_get_ret_stack(task, *graph);
+	if (!ret_stack)
+		return;
+
+	ret_addr = ret_stack->ret;
 
 	ops->address(data, ret_addr, 1);
 
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index bb511e2d9d68..df0fd6efe758 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -608,17 +608,18 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
 	 * expected to find the real return address.
 	 */
 	if (pc == (unsigned long)&return_to_handler) {
-		int index = current->curr_ret_stack;
+		struct ftrace_ret_stack *ret_stack;
 
+		ret_stack = ftrace_graph_get_ret_stack(current, 0);
+		if (ret_stack)
+			pc = ret_stack->ret;
 		/*
 		 * We currently have no way of tracking how many
 		 * return_to_handler()'s we've seen. If there is more
 		 * than one patched return address on our stack,
 		 * complain loudly.
 		 */
-		WARN_ON(index > 0);
-
-		pc = current->ret_stack[index].ret;
+		WARN_ON(ftrace_graph_get_ret_stack(current, 1);
 	}
 #endif
 
-- 
2.19.2