Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / x86 / xen / irq.c

diff --git a/kernel/arch/x86/xen/irq.c b/kernel/arch/x86/xen/irq.c
new file mode 100644 (file)
index 0000000..a1207cb
--- /dev/null
+++ b/kernel/arch/x86/xen/irq.c
@@ -0,0 +1,136 @@
+#include <linux/hardirq.h>
+
+#include <asm/x86_init.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/sched.h>
+#include <xen/interface/vcpu.h>
+#include <xen/features.h>
+#include <xen/events.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include "xen-ops.h"
+
+/*
+ * Force a proper event-channel callback from Xen after clearing the
+ * callback mask. We do this in a very simple manner, by making a call
+ * down into Xen. The pending flag will be checked by Xen on return.
+ */
+void xen_force_evtchn_callback(void)
+{
+       (void)HYPERVISOR_xen_version(0, NULL);
+}
+
+asmlinkage __visible unsigned long xen_save_fl(void)
+{
+       struct vcpu_info *vcpu;
+       unsigned long flags;
+
+       vcpu = this_cpu_read(xen_vcpu);
+
+       /* flag has opposite sense of mask */
+       flags = !vcpu->evtchn_upcall_mask;
+
+       /* convert to IF type flag
+          -0 -> 0x00000000
+          -1 -> 0xffffffff
+       */
+       return (-flags) & X86_EFLAGS_IF;
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
+
+__visible void xen_restore_fl(unsigned long flags)
+{
+       struct vcpu_info *vcpu;
+
+       /* convert from IF type flag */
+       flags = !(flags & X86_EFLAGS_IF);
+
+       /* See xen_irq_enable() for why preemption must be disabled. */
+       preempt_disable();
+       vcpu = this_cpu_read(xen_vcpu);
+       vcpu->evtchn_upcall_mask = flags;
+
+       if (flags == 0) {
+               barrier(); /* unmask then check (avoid races) */
+               if (unlikely(vcpu->evtchn_upcall_pending))
+                       xen_force_evtchn_callback();
+               preempt_enable();
+       } else
+               preempt_enable_no_resched();
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
+
+asmlinkage __visible void xen_irq_disable(void)
+{
+       /* There's a one instruction preempt window here.  We need to
+          make sure we're don't switch CPUs between getting the vcpu
+          pointer and updating the mask. */
+       preempt_disable();
+       this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
+       preempt_enable_no_resched();
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
+
+asmlinkage __visible void xen_irq_enable(void)
+{
+       struct vcpu_info *vcpu;
+
+       /*
+        * We may be preempted as soon as vcpu->evtchn_upcall_mask is
+        * cleared, so disable preemption to ensure we check for
+        * events on the VCPU we are still running on.
+        */
+       preempt_disable();
+
+       vcpu = this_cpu_read(xen_vcpu);
+       vcpu->evtchn_upcall_mask = 0;
+
+       /* Doesn't matter if we get preempted here, because any
+          pending event will get dealt with anyway. */
+
+       barrier(); /* unmask then check (avoid races) */
+       if (unlikely(vcpu->evtchn_upcall_pending))
+               xen_force_evtchn_callback();
+
+       preempt_enable();
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
+
+static void xen_safe_halt(void)
+{
+       /* Blocking includes an implicit local_irq_enable(). */
+       if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
+               BUG();
+}
+
+static void xen_halt(void)
+{
+       if (irqs_disabled())
+               HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
+       else
+               xen_safe_halt();
+}
+
+static const struct pv_irq_ops xen_irq_ops __initconst = {
+       .save_fl = PV_CALLEE_SAVE(xen_save_fl),
+       .restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
+       .irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
+       .irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
+
+       .safe_halt = xen_safe_halt,
+       .halt = xen_halt,
+#ifdef CONFIG_X86_64
+       .adjust_exception_frame = xen_adjust_exception_frame,
+#endif
+};
+
+void __init xen_init_irq_ops(void)
+{
+       /* For PVH we use default pv_irq_ops settings. */
+       if (!xen_feature(XENFEAT_hvm_callback_vector))
+               pv_irq_ops = xen_irq_ops;
+       x86_init.irqs.intr_init = xen_init_IRQ;
+}