powerpc/booke64: Check napping in performance monitor interrupt

The performance monitor interrupt is asynchronous, so we should check
if the current processor is in napping status in the handler of this
interrupt.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/exceptions-64e.S

@@ -607,6 +607,7 @@ kernel_dbg_exc:
 	NORMAL_EXCEPTION_PROLOG(0x260, BOOKE_INTERRUPT_PERFORMANCE_MONITOR,
 				PROLOG_ADDITION_NONE)
 	EXCEPTION_COMMON(0x260, PACA_EXGEN, INTS_DISABLE)
+	CHECK_NAPPING()
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	.performance_monitor_exception
 	b	.ret_from_except_lite