Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/kernel/arch/x86/kernel/irq_work.c b/kernel/arch/x86/kernel/irq_work.c
new file mode 100644
index 000000000..15d741ddf
--- /dev/null
+++ b/kernel/arch/x86/kernel/irq_work.c
@@ -0,0 +1,50 @@
+/*
+ * x86 specific code for irq_work
+ *
+ * Copyright (C) 2010 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/irq_work.h>
+#include <linux/hardirq.h>
+#include <asm/apic.h>
+#include <asm/trace/irq_vectors.h>
+
+static inline void irq_work_entering_irq(void)
+{
+	irq_enter();
+	ack_APIC_irq();
+}
+
+static inline void __smp_irq_work_interrupt(void)
+{
+	inc_irq_stat(apic_irq_work_irqs);
+	irq_work_run();
+}
+
+__visible void smp_irq_work_interrupt(struct pt_regs *regs)
+{
+	irq_work_entering_irq();
+	__smp_irq_work_interrupt();
+	exiting_irq();
+}
+
+__visible void smp_trace_irq_work_interrupt(struct pt_regs *regs)
+{
+	irq_work_entering_irq();
+	trace_irq_work_entry(IRQ_WORK_VECTOR);
+	__smp_irq_work_interrupt();
+	trace_irq_work_exit(IRQ_WORK_VECTOR);
+	exiting_irq();
+}
+
+void arch_irq_work_raise(void)
+{
+#ifdef CONFIG_X86_LOCAL_APIC
+	if (!arch_irq_work_has_interrupt())
+		return;
+
+	apic->send_IPI_self(IRQ_WORK_VECTOR);
+	apic_wait_icr_idle();
+#endif
+}