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#include <linux/hardirq.h>
#include <xen/interface/xen.h>
#include <xen/interface/sched.h>
#include <xen/interface/vcpu.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);
}
static void __init __xen_init_IRQ(void)
{
int i;
/* Create identity vector->irq map */
for(i = 0; i < NR_VECTORS; i++) {
int cpu;
for_each_possible_cpu(cpu)
per_cpu(vector_irq, cpu)[i] = i;
}
xen_init_IRQ();
}
static unsigned long xen_save_fl(void)
{
struct vcpu_info *vcpu;
unsigned long flags;
vcpu = x86_read_percpu(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;
}
static void xen_restore_fl(unsigned long flags)
{
struct vcpu_info *vcpu;
/* convert from IF type flag */
flags = !(flags & X86_EFLAGS_IF);
/* 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();
vcpu = x86_read_percpu(xen_vcpu);
vcpu->evtchn_upcall_mask = flags;
preempt_enable_no_resched();
/* Doesn't matter if we get preempted here, because any
pending event will get dealt with anyway. */
if (flags == 0) {
preempt_check_resched();
barrier(); /* unmask then check (avoid races) */
if (unlikely(vcpu->evtchn_upcall_pending))
xen_force_evtchn_callback();
}
}
static 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();
x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1;
preempt_enable_no_resched();
}
static void xen_irq_enable(void)
{
struct vcpu_info *vcpu;
/* We don't need to worry about being preempted here, since
either a) interrupts are disabled, so no preemption, or b)
the caller is confused and is trying to re-enable interrupts
on an indeterminate processor. */
vcpu = x86_read_percpu(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();
}
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 __initdata = {
.init_IRQ = __xen_init_IRQ,
.save_fl = xen_save_fl,
.restore_fl = xen_restore_fl,
.irq_disable = xen_irq_disable,
.irq_enable = 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()
{
pv_irq_ops = xen_irq_ops;
}
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