sparc32, leon: must protect IRQ controller register with spinlock

The LEON interrupt controller has one single mask register for all
IRQs per CPU, even though the genirq layer protects us from accessing
the same IRQ at the same time other IRQs share the same mask register
and may thus interfere. Some other IRQ controllers has a mask register
or similar per IRQ instead which makes spinlocks unncessary.
Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/kernel/leon_kernel.c

@@ -31,6 +31,7 @@ int leondebug_irq_disable;
 int leon_debug_irqout;
 static int dummy_master_l10_counter;
 unsigned long amba_system_id;
+static DEFINE_SPINLOCK(leon_irq_lock);
 
 unsigned long leon3_gptimer_irq; /* interrupt controller irq number */
 unsigned long leon3_gptimer_idx; /* Timer Index (0..6) within Timer Core */
@@ -88,10 +89,10 @@ static void leon_unmask_irq(struct irq_data *data)
 	unsigned long mask, flags;
 
 	mask = (unsigned long)data->chip_data;
-	local_irq_save(flags);
+	spin_lock_irqsave(&leon_irq_lock, flags);
 	LEON3_BYPASS_STORE_PA(LEON_IMASK,
 			      (LEON3_BYPASS_LOAD_PA(LEON_IMASK) | (mask)));
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&leon_irq_lock, flags);
 }
 
 static void leon_mask_irq(struct irq_data *data)
@@ -99,11 +100,10 @@ static void leon_mask_irq(struct irq_data *data)
 	unsigned long mask, flags;
 
 	mask = (unsigned long)data->chip_data;
-	local_irq_save(flags);
+	spin_lock_irqsave(&leon_irq_lock, flags);
 	LEON3_BYPASS_STORE_PA(LEON_IMASK,
 			      (LEON3_BYPASS_LOAD_PA(LEON_IMASK) & ~(mask)));
-	local_irq_restore(flags);
-
+	spin_unlock_irqrestore(&leon_irq_lock, flags);
 }
 
 static unsigned int leon_startup_irq(struct irq_data *data)
@@ -383,10 +383,10 @@ void leon_enable_irq_cpu(unsigned int irq_nr, unsigned int cpu)
 {
 	unsigned long mask, flags, *addr;
 	mask = get_irqmask(irq_nr);
-	local_irq_save(flags);
+	spin_lock_irqsave(&leon_irq_lock, flags);
 	addr = (unsigned long *)&(leon3_irqctrl_regs->mask[cpu]);
 	LEON3_BYPASS_STORE_PA(addr, (LEON3_BYPASS_LOAD_PA(addr) | (mask)));
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&leon_irq_lock, flags);
 }
 
 #endif