[for-next][PATCH 05/24] powerpc/frace: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack

Steven Rostedt
2018-12-21T17:57:00Z

From: "Steven Rostedt (VMware)" <rostedt@goodmis.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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
arch/powerpc/kernel/process.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 96f34730010f..ce393df243aa 100644
--- 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)
--
2.19.2