4.19-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt (VMware) rostedt@goodmis.org
commit 18588e1487b19e45bd90bd55ec8d3a1d44f3257f upstream.
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: Martin 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: 03274a3ffb449 ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kernel/ftrace.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-)
--- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -203,22 +203,13 @@ device_initcall(ftrace_plt_init); */ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip) { - struct ftrace_graph_ent trace; - if (unlikely(ftrace_graph_is_dead())) goto out; if (unlikely(atomic_read(¤t->tracing_graph_pause))) goto out; ip -= MCOUNT_INSN_SIZE; - trace.func = ip; - trace.depth = current->curr_ret_stack + 1; - /* 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; + if (!function_graph_enter(parent, ip, 0, NULL)) + parent = (unsigned long) return_to_handler; out: return parent; }