[ARM] gic: Fix gic cascade irq handling

No need for the cascade irq function to have a "fastcall" annotation.
Fix the range checking for valid IRQ numbers - comparing the value
returned by the GIC with NR_IRQS is meaningless since we translate
the GIC irq number to a Linux IRQ number afterwards.

Check the GIC returned IRQ number is within limits first, then add
the IRQ offset, and only then compare with NR_IRQS.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 9 insertions, 11 deletions

diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 4deece5fbdf..2ae0bd1c907 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -125,12 +125,11 @@ static void gic_set_cpu(unsigned int irq, cpumask_t mask_val)
 }
 #endif
 
-static void fastcall gic_handle_cascade_irq(unsigned int irq,
-                                            struct irq_desc *desc)
+static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
 {
         struct gic_chip_data *chip_data = get_irq_data(irq);
         struct irq_chip *chip = get_irq_chip(irq);
-        unsigned int cascade_irq;
+        unsigned int cascade_irq, gic_irq;
         unsigned long status;
 
         /* primary controller ack'ing */
@@ -140,16 +139,15 @@ static void fastcall gic_handle_cascade_irq(unsigned int irq,
         status = readl(chip_data->cpu_base + GIC_CPU_INTACK);
         spin_unlock(&irq_controller_lock);
 
-        cascade_irq = (status & 0x3ff);
-        if (cascade_irq > 1020)
+        gic_irq = (status & 0x3ff);
+        if (gic_irq == 1023)
                 goto out;
-        if (cascade_irq < 32 || cascade_irq >= NR_IRQS) {
-                do_bad_IRQ(cascade_irq, desc);
-                goto out;
-        }
 
-        cascade_irq += chip_data->irq_offset;
-        generic_handle_irq(cascade_irq);
+        cascade_irq = gic_irq + chip_data->irq_offset;
+        if (unlikely(gic_irq < 32 || gic_irq > 1020 || cascade_irq >= NR_IRQS))
+                do_bad_IRQ(cascade_irq, desc);
+        else
+                generic_handle_irq(cascade_irq);
 
  out:
         /* primary controller unmasking */