arc: unwind: warn only once if DW2_UNWIND is disabled

commit 9bd54517ee86cb164c734f72ea95aeba4804f10b upstream.

If CONFIG_ARC_DW2_UNWIND is disabled every time arc_unwind_core()
gets called following message gets printed in debug console:
----------------->8---------------
CONFIG_ARC_DW2_UNWIND needs to be enabled
----------------->8---------------

That message makes sense if user indeed wants to see a backtrace or
get nice function call-graphs in perf but what if user disabled
unwinder for the purpose? Why pollute his debug console?

So instead we'll warn user about possibly missing feature once and
let him decide if that was what he or she really wanted.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index 001de4ce711eae2b095451a52f68e77db3d81ef4..11b50959f20ed38a18d6edbe9d7da969a1970f54 100644 (file)
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -142,7 +142,7 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
         * prelogue is setup (callee regs saved and then fp set and not other
         * way around
         */
-       pr_warn("CONFIG_ARC_DW2_UNWIND needs to be enabled\n");
+       pr_warn_once("CONFIG_ARC_DW2_UNWIND needs to be enabled\n");
        return 0;
 
 #endif