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/******************************************************************************
* evtchn.h
*
* Communication via Xen event channels.
* Also definitions for the device that demuxes notifications to userspace.
*
* Copyright (c) 2004, K A Fraser
*/
#ifndef __ASM_EVTCHN_H__
#define __ASM_EVTCHN_H__
#include <linux/config.h>
#include <asm/hypervisor.h>
#include <asm/ptrace.h>
/*
* LOW-LEVEL DEFINITIONS
*/
/* Entry point for notifications into Linux subsystems. */
void evtchn_do_upcall(struct pt_regs *regs);
/* Entry point for notifications into the userland character device. */
void evtchn_device_upcall(int port, int exception);
static inline void mask_evtchn(int port)
{
shared_info_t *s = HYPERVISOR_shared_info;
set_bit(port, &s->evtchn_mask[0]);
}
/*
* I haven't thought too much about the synchronisation in here against
* other CPUs, but all the bit-update operations are reorder barriers on
* x86 so reordering concerns aren't a problem for now. Some mb() calls
* would be required on weaker architectures I think. -- KAF (24/3/2004)
*/
static inline void unmask_evtchn(int port)
{
shared_info_t *s = HYPERVISOR_shared_info;
int need_upcall = 0;
clear_bit(port, &s->evtchn_mask[0]);
/*
* The following is basically the equivalent of 'hw_resend_irq'. Just like
* a real IO-APIC we 'lose the interrupt edge' if the channel is masked.
*/
/* Asserted a standard notification? */
if ( test_bit (port, &s->evtchn_pending[0]) &&
!test_and_set_bit(port>>5, &s->evtchn_pending_sel) )
need_upcall = 1;
/* Asserted an exceptional notification? */
if ( test_bit (port, &s->evtchn_exception[0]) &&
!test_and_set_bit(port>>5, &s->evtchn_exception_sel) )
need_upcall = 1;
/* If asserted either type of notification, check the master flags. */
if ( need_upcall &&
!test_and_set_bit(0, &s->evtchn_upcall_pending) &&
!test_bit (0, &s->evtchn_upcall_mask) )
evtchn_do_upcall(NULL);
}
static inline void clear_evtchn(int port)
{
shared_info_t *s = HYPERVISOR_shared_info;
clear_bit(port, &s->evtchn_pending[0]);
}
static inline void clear_evtchn_exception(int port)
{
shared_info_t *s = HYPERVISOR_shared_info;
clear_bit(port, &s->evtchn_exception[0]);
}
/*
* CHARACTER-DEVICE DEFINITIONS
*/
#define PORT_NORMAL 0x0000
#define PORT_EXCEPTION 0x8000
#define PORTIDX_MASK 0x7fff
/* /dev/xen/evtchn resides at device number major=10, minor=200 */
#define EVTCHN_MINOR 200
/* /dev/xen/evtchn ioctls: */
/* EVTCHN_RESET: Clear and reinit the event buffer. Clear error condition. */
#define EVTCHN_RESET _IO('E', 1)
#endif /* __ASM_EVTCHN_H__ */
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