1 #include <linux/hardirq.h>
3 #include <xen/interface/xen.h>
4 #include <xen/interface/sched.h>
5 #include <xen/interface/vcpu.h>
7 #include <asm/xen/hypercall.h>
8 #include <asm/xen/hypervisor.h>
13 * Force a proper event-channel callback from Xen after clearing the
14 * callback mask. We do this in a very simple manner, by making a call
15 * down into Xen. The pending flag will be checked by Xen on return.
17 void xen_force_evtchn_callback(void)
19 (void)HYPERVISOR_xen_version(0, NULL);
22 static void __init __xen_init_IRQ(void)
26 /* Create identity vector->irq map */
27 for(i = 0; i < NR_VECTORS; i++) {
30 for_each_possible_cpu(cpu)
31 per_cpu(vector_irq, cpu)[i] = i;
37 static unsigned long xen_save_fl(void)
39 struct vcpu_info *vcpu;
42 vcpu = percpu_read(xen_vcpu);
44 /* flag has opposite sense of mask */
45 flags = !vcpu->evtchn_upcall_mask;
47 /* convert to IF type flag
51 return (-flags) & X86_EFLAGS_IF;
53 PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
55 static void xen_restore_fl(unsigned long flags)
57 struct vcpu_info *vcpu;
59 /* convert from IF type flag */
60 flags = !(flags & X86_EFLAGS_IF);
62 /* There's a one instruction preempt window here. We need to
63 make sure we're don't switch CPUs between getting the vcpu
64 pointer and updating the mask. */
66 vcpu = percpu_read(xen_vcpu);
67 vcpu->evtchn_upcall_mask = flags;
68 preempt_enable_no_resched();
70 /* Doesn't matter if we get preempted here, because any
71 pending event will get dealt with anyway. */
74 preempt_check_resched();
75 barrier(); /* unmask then check (avoid races) */
76 if (unlikely(vcpu->evtchn_upcall_pending))
77 xen_force_evtchn_callback();
80 PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
82 static void xen_irq_disable(void)
84 /* There's a one instruction preempt window here. We need to
85 make sure we're don't switch CPUs between getting the vcpu
86 pointer and updating the mask. */
88 percpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
89 preempt_enable_no_resched();
91 PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
93 static void xen_irq_enable(void)
95 struct vcpu_info *vcpu;
97 /* We don't need to worry about being preempted here, since
98 either a) interrupts are disabled, so no preemption, or b)
99 the caller is confused and is trying to re-enable interrupts
100 on an indeterminate processor. */
102 vcpu = percpu_read(xen_vcpu);
103 vcpu->evtchn_upcall_mask = 0;
105 /* Doesn't matter if we get preempted here, because any
106 pending event will get dealt with anyway. */
108 barrier(); /* unmask then check (avoid races) */
109 if (unlikely(vcpu->evtchn_upcall_pending))
110 xen_force_evtchn_callback();
112 PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
114 static void xen_safe_halt(void)
116 /* Blocking includes an implicit local_irq_enable(). */
117 if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
121 static void xen_halt(void)
124 HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
129 static const struct pv_irq_ops xen_irq_ops __initdata = {
130 .init_IRQ = __xen_init_IRQ,
132 .save_fl = PV_CALLEE_SAVE(xen_save_fl),
133 .restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
134 .irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
135 .irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
137 .safe_halt = xen_safe_halt,
140 .adjust_exception_frame = xen_adjust_exception_frame,
144 void __init xen_init_irq_ops()
146 pv_irq_ops = xen_irq_ops;