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ARM: function_graph: Simplify with function_graph_enter() 

The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().

Have ARM use the new code, and remove the shadow stack management as well as
having to set up the trace structure.

This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.

Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@kernel.org
Fixes: 03274a3ffb ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
hifive-unleashed-5.1
Steven Rostedt (VMware) 2018-11-18 17:19:26 -05:00
parent 07f7175b43
commit f1f5b14afd
1 changed files with 1 additions and 16 deletions
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17
arch/arm/kernel/ftrace.c
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@ -183,9 +183,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
unsigned long frame_pointer)
{
unsigned long return_hooker = (unsigned long) &return_to_handler;
struct ftrace_graph_ent trace;
unsigned long old;
int err;
if (unlikely(atomic_read(&current->tracing_graph_pause)))
return;
@ -193,21 +191,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
old = *parent;
*parent = return_hooker;
trace.func = self_addr;
trace.depth = current->curr_ret_stack + 1;
/* Only trace if the calling function expects to */
if (!ftrace_graph_entry(&trace)) {
if (function_graph_enter(old, self_addr, frame_pointer, NULL))
*parent = old;
return;
}
err = ftrace_push_return_trace(old, self_addr, &trace.depth,
frame_pointer, NULL);
if (err == -EBUSY) {
*parent = old;
return;
}
}
#ifdef CONFIG_DYNAMIC_FTRACE