Re: [PATCH v3] powerpc/ppc64: Use preempt_schedule_irq instead of preempt_schedule

Benjamin Herrenschmidt wrote:

On Wed, 2009-10-28 at 22:19 +0300, Valentine wrote:

quoted

I'm just not sure that we need to clear HARDIRQEN here, since we don't 
really hard-disable the the interrupts.

We do, or rather, we come in with the interrupts hard disabled, no ?

Yes, looks like the interrupts are disabled at this point (before 
preempt_schedule_irq) most of the times, but we don't hard-disable them 
here. We just soft-disable them to make preempt_schedule_irq happy. Even 
if an interrupt fires, it will be hard-disabled and the hardirq flag 
will be cleared by the exception handler right away. I just think that 
there's no need to clear hardirq flag if we don't clear MSR_EE.

Thanks,
Val.

Ben.

quoted

Thanks,
Val.

quoted

+	TRACE_DISABLE_INTS
+
+	/* Call the scheduler with soft IRQs off */
+1:	bl	.preempt_schedule_irq
+
+	/* Hard-disable interrupts again (and update PACA) */
 #ifdef CONFIG_PPC_BOOK3E
-	wrteei	1
-	bl	.preempt_schedule
 	wrteei	0
 #else
-	ori	r10,r10,MSR_EE
-	mtmsrd	r10,1		/* reenable interrupts */
-	bl	.preempt_schedule
 	mfmsr	r10
-	clrrdi	r9,r1,THREAD_SHIFT
-	rldicl	r10,r10,48,1	/* disable interrupts again */
+	rldicl	r10,r10,48,1
 	rotldi	r10,r10,16
 	mtmsrd	r10,1
 #endif /* CONFIG_PPC_BOOK3E */
+	li	r0,0
+	stb	r0,PACAHARDIRQEN(r13)
+
+	/* Re-test flags and eventually loop */
+	clrrdi	r9,r1,THREAD_SHIFT
 	ld	r4,TI_FLAGS(r9)
 	andi.	r0,r4,_TIF_NEED_RESCHED
 	bne	1b
 	b	restore
 
 user_work:
-#endif
+#endif /* CONFIG_PREEMPT */
+
 	/* Enable interrupts */
 #ifdef CONFIG_PPC_BOOK3E
 	wrteei	1