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// SPDX-License-Identifier: GPL-2.0+
/*
* Pvpanic Device Support
*
* Copyright (C) 2013 Fujitsu.
* Copyright (C) 2018 ZTE.
* Copyright (C) 2021 Oracle.
*/
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/panic_notifier.h>
#include <linux/types.h>
#include <linux/cdev.h>
#include <linux/list.h>
#include <uapi/misc/pvpanic.h>
#include "pvpanic.h"
MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
MODULE_DESCRIPTION("pvpanic device driver");
MODULE_LICENSE("GPL");
static struct list_head pvpanic_list;
static spinlock_t pvpanic_lock;
static void
pvpanic_send_event(unsigned int event)
{
struct pvpanic_instance *pi_cur;
if (!spin_trylock(&pvpanic_lock))
return;
list_for_each_entry(pi_cur, &pvpanic_list, list) {
if (event & pi_cur->capability & pi_cur->events)
iowrite8(event, pi_cur->base);
}
spin_unlock(&pvpanic_lock);
}
static int
pvpanic_panic_notify(struct notifier_block *nb, unsigned long code, void *unused)
{
unsigned int event = PVPANIC_PANICKED;
if (kexec_crash_loaded())
event = PVPANIC_CRASH_LOADED;
pvpanic_send_event(event);
return NOTIFY_DONE;
}
/*
* Call our notifier very early on panic, deferring the
* action taken to the hypervisor.
*/
static struct notifier_block pvpanic_panic_nb = {
.notifier_call = pvpanic_panic_notify,
.priority = INT_MAX,
};
static void pvpanic_remove(void *param)
{
struct pvpanic_instance *pi_cur, *pi_next;
struct pvpanic_instance *pi = param;
spin_lock(&pvpanic_lock);
list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
if (pi_cur == pi) {
list_del(&pi_cur->list);
break;
}
}
spin_unlock(&pvpanic_lock);
}
int devm_pvpanic_probe(struct device *dev, struct pvpanic_instance *pi)
{
if (!pi || !pi->base)
return -EINVAL;
spin_lock(&pvpanic_lock);
list_add(&pi->list, &pvpanic_list);
spin_unlock(&pvpanic_lock);
dev_set_drvdata(dev, pi);
return devm_add_action_or_reset(dev, pvpanic_remove, pi);
}
EXPORT_SYMBOL_GPL(devm_pvpanic_probe);
static int pvpanic_init(void)
{
INIT_LIST_HEAD(&pvpanic_list);
spin_lock_init(&pvpanic_lock);
atomic_notifier_chain_register(&panic_notifier_list, &pvpanic_panic_nb);
return 0;
}
module_init(pvpanic_init);
static void pvpanic_exit(void)
{
atomic_notifier_chain_unregister(&panic_notifier_list, &pvpanic_panic_nb);
}
module_exit(pvpanic_exit);
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