s390/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 s390 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.
Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Julian Wiedmann <jwi@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: stable@kernel.org
Fixes: 03274a3f ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent e949b6db
...@@ -203,22 +203,13 @@ device_initcall(ftrace_plt_init); ...@@ -203,22 +203,13 @@ device_initcall(ftrace_plt_init);
*/ */
unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip) unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
{ {
struct ftrace_graph_ent trace;
if (unlikely(ftrace_graph_is_dead())) if (unlikely(ftrace_graph_is_dead()))
goto out; goto out;
if (unlikely(atomic_read(&current->tracing_graph_pause))) if (unlikely(atomic_read(&current->tracing_graph_pause)))
goto out; goto out;
ip -= MCOUNT_INSN_SIZE; ip -= MCOUNT_INSN_SIZE;
trace.func = ip; if (!function_graph_enter(parent, ip, 0, NULL))
trace.depth = current->curr_ret_stack + 1; parent = (unsigned long) return_to_handler;
/* Only trace if the calling function expects to. */
if (!ftrace_graph_entry(&trace))
goto out;
if (ftrace_push_return_trace(parent, ip, &trace.depth, 0,
NULL) == -EBUSY)
goto out;
parent = (unsigned long) return_to_handler;
out: out:
return parent; return parent;
} }
......
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