powerpc/frace: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack

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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 96f34730010fe3f5f778400a14a7a470d4d38142..ce393df243aa3a642935c78e37a943e58cddf1fe 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2061,9 +2061,10 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
        int count = 0;
        int firstframe = 1;
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-       int curr_frame = current->curr_ret_stack;
+       struct ftrace_ret_stack *ret_stack;
        extern void return_to_handler(void);
        unsigned long rth = (unsigned long)return_to_handler;
+       int curr_frame = 0;
 #endif
 
        sp = (unsigned long) stack;
@@ -2089,9 +2090,13 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
                        printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
                        if ((ip == rth) && curr_frame >= 0) {
-                               pr_cont(" (%pS)",
-                                      (void *)current->ret_stack[curr_frame].ret);
-                               curr_frame--;
+                               ret_stack = ftrace_graph_get_ret_stack(current,
+                                                                 curr_frame++);
+                               if (ret_stack)
+                                       pr_cont(" (%pS)",
+                                               (void *)ret_stack->ret);
+                               else
+                                       curr_frame = -1;
                        }
 #endif
                        if (firstframe)