sparc64: Add interface for registering a performance counter IRQ handler.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc64/kernel/irq.c b/arch/sparc64/kernel/irq.c
index 52fc836..a3ea2bc 100644
--- a/arch/sparc64/kernel/irq.c
+++ b/arch/sparc64/kernel/irq.c
@@ -775,6 +775,69 @@
local_irq_restore(flags);
}
+static void unhandled_perf_irq(struct pt_regs *regs)
+{
+ unsigned long pcr, pic;
+
+ read_pcr(pcr);
+ read_pic(pic);
+
+ write_pcr(0);
+
+ printk(KERN_EMERG "CPU %d: Got unexpected perf counter IRQ.\n",
+ smp_processor_id());
+ printk(KERN_EMERG "CPU %d: PCR[%016lx] PIC[%016lx]\n",
+ smp_processor_id(), pcr, pic);
+}
+
+/* Almost a direct copy of the powerpc PMC code. */
+static DEFINE_SPINLOCK(perf_irq_lock);
+static void *perf_irq_owner_caller; /* mostly for debugging */
+static void (*perf_irq)(struct pt_regs *regs) = unhandled_perf_irq;
+
+/* Invoked from level 15 PIL handler in trap table. */
+void perfctr_irq(int irq, struct pt_regs *regs)
+{
+ clear_softint(1 << irq);
+ perf_irq(regs);
+}
+
+int register_perfctr_intr(void (*handler)(struct pt_regs *))
+{
+ int ret;
+
+ if (!handler)
+ return -EINVAL;
+
+ spin_lock(&perf_irq_lock);
+ if (perf_irq != unhandled_perf_irq) {
+ printk(KERN_WARNING "register_perfctr_intr: "
+ "perf IRQ busy (reserved by caller %p)\n",
+ perf_irq_owner_caller);
+ ret = -EBUSY;
+ goto out;
+ }
+
+ perf_irq_owner_caller = __builtin_return_address(0);
+ perf_irq = handler;
+
+ ret = 0;
+out:
+ spin_unlock(&perf_irq_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(register_perfctr_intr);
+
+void release_perfctr_intr(void (*handler)(struct pt_regs *))
+{
+ spin_lock(&perf_irq_lock);
+ perf_irq_owner_caller = NULL;
+ perf_irq = unhandled_perf_irq;
+ spin_unlock(&perf_irq_lock);
+}
+EXPORT_SYMBOL_GPL(release_perfctr_intr);
+
#ifdef CONFIG_HOTPLUG_CPU
void fixup_irqs(void)
{