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

[Steven Rostedt]

On Sat, 22 Dec 2018 20:51:21 +1100
Michael Ellerman  wrote:


> I did test the previous series you posted and I think everything was OK
> running the ftracetest suite (I got one or two fails but I think that
> was because of missing CONFIG options).
> 
> Acked-by: Michael Ellerman  (powerpc)

Thanks! I'll add your ack.

-- Steve

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

[Michael Ellerman]

Steven Rostedt  writes:

> From: "Steven Rostedt (VMware)" 
>
> 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 
> Cc: Paul Mackerras 
> Cc: Michael Ellerman 
> Cc: linuxppc-dev@lists.ozlabs.org
> Signed-off-by: Steven Rostedt (VMware) 
> ---
>  arch/powerpc/kernel/process.c | 13 +
>  1 file changed, 9 insertions(+), 4 deletions(-)

I did test the previous series you posted and I think everything was OK
running the ftracetest suite (I got one or two fails but I think that
was because of missing CONFIG options).

Acked-by: Michael Ellerman  (powerpc)

cheers

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

[Steven Rostedt]

From: "Steven Rostedt (VMware)" 

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 
Cc: Paul Mackerras 
Cc: Michael Ellerman 
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Steven Rostedt (VMware) 
---
 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