[PATCH] ppc64: Remove lpqueue pointer from the paca on iSeries

The iSeries code keeps a pointer to the ItLpQueue in its paca struct. But
all these pointers end up pointing to the one place, ie. xItLpQueue.

So remove the pointer from the paca struct and just refer to xItLpQueue
directly where needed.

The only complication is that the spread_lpevents logic was implemented by
having a NULL lpqueue pointer in the paca on CPUs that weren't supposed to
process events. Instead we just compare the spread_lpevents value to the
processor id to get the same behaviour.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/ppc64/kernel/ItLpQueue.c

@@ -69,15 +69,17 @@ struct HvLpEvent * ItLpQueue_getNextLpEvent( struct ItLpQueue * lpQueue )
 	return nextLpEvent;
 }
 
+unsigned long spread_lpevents = 1;
+
 int ItLpQueue_isLpIntPending( struct ItLpQueue * lpQueue )
 {
-	int retval = 0;
-	struct HvLpEvent * nextLpEvent;
-	if ( lpQueue ) {
-		nextLpEvent = (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
-		retval = nextLpEvent->xFlags.xValid | lpQueue->xPlicOverflowIntPending;
-	}
-	return retval;
+	struct HvLpEvent *next_event;
+
+	if (smp_processor_id() >= spread_lpevents)
+		return 0;
+
+	next_event = (struct HvLpEvent *)lpQueue->xSlicCurEventPtr;
+	return next_event->xFlags.xValid | lpQueue->xPlicOverflowIntPending;
 }
 
 void ItLpQueue_clearValid( struct HvLpEvent * event )

arch/ppc64/kernel/iSeries_setup.c

@@ -855,17 +855,15 @@ late_initcall(iSeries_src_init);
 
 static int set_spread_lpevents(char *str)
 {
-	unsigned long i;
 	unsigned long val = simple_strtoul(str, NULL, 0);
+	extern unsigned long spread_lpevents;
 
 	/*
 	 * The parameter is the number of processors to share in processing
 	 * lp events.
 	 */
 	if (( val > 0) && (val <= NR_CPUS)) {
-		for (i = 1; i < val; ++i)
-			paca[i].lpqueue_ptr = paca[0].lpqueue_ptr;
-
+		spread_lpevents = val;
 		printk("lpevent processing spread over %ld processors\n", val);
 	} else {
 		printk("invalid spread_lpevents %ld\n", val);

arch/ppc64/kernel/idle.c

@@ -88,7 +88,7 @@ static int iSeries_idle(void)
 
 	while (1) {
 		if (lpaca->lppaca.shared_proc) {
-			if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
+			if (ItLpQueue_isLpIntPending(&xItLpQueue))
 				process_iSeries_events();
 			if (!need_resched())
 				yield_shared_processor();
@@ -100,7 +100,7 @@ static int iSeries_idle(void)
 
 				while (!need_resched()) {
 					HMT_medium();
-					if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
+					if (ItLpQueue_isLpIntPending(&xItLpQueue))
 						process_iSeries_events();
 					HMT_low();
 				}

arch/ppc64/kernel/irq.c

@@ -269,7 +269,6 @@ void ppc_irq_dispatch_handler(struct pt_regs *regs, int irq)
 void do_IRQ(struct pt_regs *regs)
 {
 	struct paca_struct *lpaca;
-	struct ItLpQueue *lpq;
 
 	irq_enter();
 
@@ -295,9 +294,8 @@ void do_IRQ(struct pt_regs *regs)
 		iSeries_smp_message_recv(regs);
 	}
 #endif /* CONFIG_SMP */
-	lpq = lpaca->lpqueue_ptr;
-	if (lpq && ItLpQueue_isLpIntPending(lpq))
-		lpevent_count += ItLpQueue_process(lpq, regs);
+	if (ItLpQueue_isLpIntPending(&xItLpQueue))
+		lpevent_count += ItLpQueue_process(&xItLpQueue, regs);
 
 	irq_exit();
 

arch/ppc64/kernel/mf.c

@@ -802,9 +802,8 @@ int mf_get_boot_rtc(struct rtc_time *tm)
 	/* We need to poll here as we are not yet taking interrupts */
 	while (rtc_data.busy) {
 		extern unsigned long lpevent_count;
-		struct ItLpQueue *lpq = get_paca()->lpqueue_ptr;
-		if (lpq && ItLpQueue_isLpIntPending(lpq))
-			lpevent_count += ItLpQueue_process(lpq, NULL);
+		if (ItLpQueue_isLpIntPending(&xItLpQueue))
+			lpevent_count += ItLpQueue_process(&xItLpQueue, NULL);
 	}
 	return rtc_set_tm(rtc_data.rc, rtc_data.ce_msg.ce_msg, tm);
 }

arch/ppc64/kernel/pacaData.c

@@ -45,7 +45,6 @@ extern unsigned long __toc_start;
 #ifdef CONFIG_PPC_ISERIES
 #define EXTRA_INITS(number, lpq)					    \
 	.lppaca_ptr = &paca[number].lppaca,				    \
-	.lpqueue_ptr = (lpq),		/* &xItLpQueue, */		    \
 	.reg_save_ptr = &paca[number].reg_save,				    \
 	.reg_save = {							    \
 		.xDesc = 0xd397d9e2,	/* "LpRS" */			    \

arch/ppc64/kernel/time.c

@@ -367,11 +367,8 @@ int timer_interrupt(struct pt_regs * regs)
 	set_dec(next_dec);
 
 #ifdef CONFIG_PPC_ISERIES
-	{
-		struct ItLpQueue *lpq = lpaca->lpqueue_ptr;
-		if (lpq && ItLpQueue_isLpIntPending(lpq))
-			lpevent_count += ItLpQueue_process(lpq, regs);
-	}
+	if (ItLpQueue_isLpIntPending(&xItLpQueue))
+		lpevent_count += ItLpQueue_process(&xItLpQueue, regs);
 #endif
 
 /* collect purr register values often, for accurate calculations */

include/asm-ppc64/paca.h

@@ -20,7 +20,6 @@
 #include	<asm/types.h>
 #include	<asm/lppaca.h>
 #include	<asm/iSeries/ItLpRegSave.h>
-#include	<asm/iSeries/ItLpQueue.h>
 #include	<asm/mmu.h>
 
 register struct paca_struct *local_paca asm("r13");
@@ -62,7 +61,6 @@ struct paca_struct {
 	u16 paca_index;			/* Logical processor number */
 
 	u32 default_decr;		/* Default decrementer value */
-	struct ItLpQueue *lpqueue_ptr;	/* LpQueue handled by this CPU */
 	u64 kernel_toc;			/* Kernel TOC address */
 	u64 stab_real;			/* Absolute address of segment table */
 	u64 stab_addr;			/* Virtual address of segment table */