From: Jake Moilanen <moilanen@austin.ibm.com>
In xics_get_irq(), for a real-to-virt irq lookup, go down the
slowpath by looking through the entire virt_irq_to_real_map array
if take a miss on the radix tree. This is possible, when an
interrupt is taken before the driver has called request_irq() (eg IDE).
---
25-akpm/arch/ppc64/kernel/irq.c | 33 +++++++++++++++++++++++++++++++++
25-akpm/arch/ppc64/kernel/xics.c | 4 ++++
2 files changed, 37 insertions(+)
diff -puN arch/ppc64/kernel/irq.c~ppc64-ide_request_irq arch/ppc64/kernel/irq.c
--- 25/arch/ppc64/kernel/irq.c~ppc64-ide_request_irq 2004-03-14 15:35:09.508493072 -0800
+++ 25-akpm/arch/ppc64/kernel/irq.c 2004-03-14 15:35:09.511492616 -0800
@@ -910,4 +910,37 @@ int virt_irq_create_mapping(unsigned int
return NO_IRQ;
}
+/*
+ * In most cases will get a hit on the very first slot checked in the
+ * virt_irq_to_real_map. Only when there are a large number of
+ * IRQs will this be expensive.
+ */
+unsigned int real_irq_to_virt_slowpath(unsigned int real_irq)
+{
+ unsigned int virq;
+ unsigned int first_virq;
+
+ virq = real_irq;
+
+ if (virq > MAX_VIRT_IRQ)
+ virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;
+
+ first_virq = virq;
+
+ do {
+ if (virt_irq_to_real_map[virq] == real_irq)
+ return virq;
+
+ virq++;
+
+ if (virq >= MAX_VIRT_IRQ)
+ virq = 0;
+
+ } while (first_virq != virq);
+
+ return NO_IRQ;
+
+}
+
+
#endif
diff -puN arch/ppc64/kernel/xics.c~ppc64-ide_request_irq arch/ppc64/kernel/xics.c
--- 25/arch/ppc64/kernel/xics.c~ppc64-ide_request_irq 2004-03-14 15:35:09.509492920 -0800
+++ 25-akpm/arch/ppc64/kernel/xics.c 2004-03-14 15:35:09.512492464 -0800
@@ -327,6 +327,8 @@ static void xics_mask_and_ack_irq(unsign
}
}
+extern unsigned int real_irq_to_virt_slowpath(unsigned int real_irq);
+
int xics_get_irq(struct pt_regs *regs)
{
unsigned int cpu = smp_processor_id();
@@ -349,6 +351,8 @@ int xics_get_irq(struct pt_regs *regs)
irq = -1;
} else {
irq = real_irq_to_virt(vec);
+ if (irq == NO_IRQ)
+ irq = real_irq_to_virt_slowpath(vec);
if (irq == NO_IRQ) {
printk(KERN_ERR "Interrupt 0x%x (real) is invalid,"
" disabling it.\n", vec);
_