sh: resume_kernel fix for kernel oops built with CONFIG_BKL_PREEMPT=y.

This patch fixes a problem within the SH implementation of resume_kernel code,
that implements in assembly the bulk of preempt_schedule_irq function without
taking care of the extra code needed to handle the BKL preemptible.

The patch basically consists of removing this asm code and calling the common
C implementation (see kernel/sched.c) as other archs do.

Another change is the missing 'cli' macro invocation at the beginning of
the resume_kernel.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/entry-common.S

@@ -92,6 +92,7 @@ ENTRY(ret_from_irq)
 	bra	resume_userspace
 	 nop
 ENTRY(resume_kernel)
+	cli
 	mov.l	@(TI_PRE_COUNT,r8), r0	! current_thread_info->preempt_count
 	tst	r0, r0
 	bf	noresched
@@ -105,28 +106,9 @@ need_resched:
 	and	#0xf0, r0		! interrupts off (exception path)?
 	cmp/eq	#0xf0, r0
 	bt	noresched
-
-	mov.l	1f, r0
-	mov.l	r0, @(TI_PRE_COUNT,r8)
-
-#ifdef CONFIG_TRACE_IRQFLAGS
 	mov.l	3f, r0
-	jsr	@r0
-	 nop
-#endif
-	sti
-	mov.l	2f, r0
-	jsr	@r0
-	 nop
-	mov	#0, r0
-	mov.l	r0, @(TI_PRE_COUNT,r8)
-	cli
-#ifdef CONFIG_TRACE_IRQFLAGS
-	mov.l	4f, r0
-	jsr	@r0
+	jsr	@r0			! call preempt_schedule_irq
 	 nop
-#endif
-
 	bra	need_resched
 	 nop
 
@@ -137,10 +119,7 @@ noresched:
 	.align 2
 1:	.long	PREEMPT_ACTIVE
 2:	.long	schedule
-#ifdef CONFIG_TRACE_IRQFLAGS
-3:	.long	trace_hardirqs_on
-4:	.long	trace_hardirqs_off
-#endif
+3:	.long	preempt_schedule_irq
 #endif
 
 ENTRY(resume_userspace)