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// SPDX-License-Identifier: GPL-2.0
/*
* (C) 2003 - Rolf Neugebauer - Intel Research Cambridge
* (C) 2005 - Grzegorz Milos - Intel Research Cambridge
* (C) 2020 - EPAM Systems Inc.
*
* File: events.c [1]
* Author: Rolf Neugebauer (neugebar@dcs.gla.ac.uk)
* Changes: Grzegorz Milos (gm281@cam.ac.uk)
*
* Date: Jul 2003, changes Jun 2005
*
* Description: Deals with events received on event channels
*
* [1] - http://xenbits.xen.org/gitweb/?p=mini-os.git;a=summary
*/
#include <common.h>
#include <log.h>
#include <asm/io.h>
#include <asm/xen/system.h>
#include <xen/events.h>
#include <xen/hvm.h>
#if IS_ENABLED(CONFIG_XEN_SERIAL)
extern u32 console_evtchn;
#endif /* IS_ENABLED(CONFIG_XEN_SERIAL) */
#define NR_EVS 1024
/**
* struct _ev_action - represents a event handler.
*
* Chaining or sharing is not allowed
*/
struct _ev_action {
void (*handler)(evtchn_port_t port, struct pt_regs *regs, void *data);
void *data;
u32 count;
};
static struct _ev_action ev_actions[NR_EVS];
void default_handler(evtchn_port_t port, struct pt_regs *regs, void *data);
static unsigned long bound_ports[NR_EVS / (8 * sizeof(unsigned long))];
void unbind_all_ports(void)
{
int i;
int cpu = 0;
struct shared_info *s = HYPERVISOR_shared_info;
struct vcpu_info *vcpu_info = &s->vcpu_info[cpu];
for (i = 0; i < NR_EVS; i++) {
#if IS_ENABLED(CONFIG_XEN_SERIAL)
if (i == console_evtchn)
continue;
#endif /* IS_ENABLED(CONFIG_XEN_SERIAL) */
if (test_and_clear_bit(i, bound_ports)) {
printf("port %d still bound!\n", i);
unbind_evtchn(i);
}
}
vcpu_info->evtchn_upcall_pending = 0;
vcpu_info->evtchn_pending_sel = 0;
}
int do_event(evtchn_port_t port, struct pt_regs *regs)
{
struct _ev_action *action;
clear_evtchn(port);
if (port >= NR_EVS) {
printk("WARN: do_event(): Port number too large: %d\n", port);
return 1;
}
action = &ev_actions[port];
action->count++;
/* call the handler */
action->handler(port, regs, action->data);
return 1;
}
evtchn_port_t bind_evtchn(evtchn_port_t port,
void (*handler)(evtchn_port_t, struct pt_regs *, void *),
void *data)
{
if (ev_actions[port].handler != default_handler)
printf("WARN: Handler for port %d already registered, replacing\n",
port);
ev_actions[port].data = data;
wmb();
ev_actions[port].handler = handler;
synch_set_bit(port, bound_ports);
return port;
}
/**
* unbind_evtchn() - Unbind event channel for selected port
*/
void unbind_evtchn(evtchn_port_t port)
{
struct evtchn_close close;
int rc;
if (ev_actions[port].handler == default_handler)
debug("Default handler for port %d when unbinding\n", port);
mask_evtchn(port);
clear_evtchn(port);
ev_actions[port].handler = default_handler;
wmb();
ev_actions[port].data = NULL;
synch_clear_bit(port, bound_ports);
close.port = port;
rc = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
if (rc)
printf("WARN: close_port %d failed rc=%d. ignored\n", port, rc);
}
void default_handler(evtchn_port_t port, struct pt_regs *regs, void *ignore)
{
debug("[Port %d] - event received\n", port);
}
/**
* evtchn_alloc_unbound() - Create a port available to the pal for
* exchanging notifications.
*
* Unfortunate confusion of terminology: the port is unbound as far
* as Xen is concerned, but we automatically bind a handler to it.
*
* Return: The result of the hypervisor call.
*/
int evtchn_alloc_unbound(domid_t pal,
void (*handler)(evtchn_port_t, struct pt_regs *, void *),
void *data, evtchn_port_t *port)
{
int rc;
struct evtchn_alloc_unbound op;
op.dom = DOMID_SELF;
op.remote_dom = pal;
rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &op);
if (rc) {
printf("ERROR: alloc_unbound failed with rc=%d", rc);
return rc;
}
if (!handler)
handler = default_handler;
*port = bind_evtchn(op.port, handler, data);
return rc;
}
/**
* eventchn_poll() - Event channel polling function
*
* Check and process any pending events
*/
void eventchn_poll(void)
{
do_hypervisor_callback(NULL);
}
/**
* init_events() - Initialize event handler
*
* Initially all events are without a handler and disabled.
*/
void init_events(void)
{
int i;
debug("%s\n", __func__);
for (i = 0; i < NR_EVS; i++) {
ev_actions[i].handler = default_handler;
mask_evtchn(i);
}
}
/**
* fini_events() - Close all ports
*
* Mask and clear event channels. Close port using EVTCHNOP_close
* hypercall.
*/
void fini_events(void)
{
debug("%s\n", __func__);
/* Dealloc all events */
unbind_all_ports();
}
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