[linux-2.6-block.git] / drivers / misc / pvpanic / pvpanic.c

// 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);
Commit	Line	Data
6861d27c MC	1	// SPDX-License-Identifier: GPL-2.0+
	2	/*
	3	* Pvpanic Device Support
	4	*
	5	* Copyright (C) 2013 Fujitsu.
	6	* Copyright (C) 2018 ZTE.
	7	* Copyright (C) 2021 Oracle.
	8	*/
	9
	10	#include <linux/io.h>
	11	#include <linux/kernel.h>
	12	#include <linux/kexec.h>
	13	#include <linux/mod_devicetable.h>
	14	#include <linux/module.h>
	15	#include <linux/platform_device.h>
f39650de	16	#include <linux/panic_notifier.h>
6861d27c	17	#include <linux/types.h>
b3c0f877 MC	18	#include <linux/cdev.h>
b3c0f877 MC	19	#include <linux/list.h>
6861d27c MC	20
	21	#include <uapi/misc/pvpanic.h>
	22
	23	#include "pvpanic.h"
	24
	25	MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
84b0f12a	26	MODULE_DESCRIPTION("pvpanic device driver");
6861d27c MC	27	MODULE_LICENSE("GPL");
6861d27c MC	28
391e2415 Y	29	static struct list_head pvpanic_list;
391e2415 Y	30	static spinlock_t pvpanic_lock;
6861d27c MC	31
	32	static void
	33	pvpanic_send_event(unsigned int event)
	34	{
b3c0f877 MC	35	struct pvpanic_instance *pi_cur;
b3c0f877 MC	36
e918c102 GP	37	if (!spin_trylock(&pvpanic_lock))
	38	return;
	39
b3c0f877 MC	40	list_for_each_entry(pi_cur, &pvpanic_list, list) {
	41	if (event & pi_cur->capability & pi_cur->events)
	42	iowrite8(event, pi_cur->base);
	43	}
	44	spin_unlock(&pvpanic_lock);
6861d27c MC	45	}
	46
	47	static int
84b0f12a	48	pvpanic_panic_notify(struct notifier_block nb, unsigned long code, void unused)
6861d27c MC	49	{
	50	unsigned int event = PVPANIC_PANICKED;
	51
	52	if (kexec_crash_loaded())
	53	event = PVPANIC_CRASH_LOADED;
	54
	55	pvpanic_send_event(event);
	56
	57	return NOTIFY_DONE;
	58	}
	59
e918c102 GP	60	/*
	61	* Call our notifier very early on panic, deferring the
	62	* action taken to the hypervisor.
	63	*/
6861d27c MC	64	static struct notifier_block pvpanic_panic_nb = {
6861d27c MC	65	.notifier_call = pvpanic_panic_notify,
e918c102	66	.priority = INT_MAX,
6861d27c MC	67	};
6861d27c MC	68
394febc9	69	static void pvpanic_remove(void *param)
6861d27c	70	{
b3c0f877	71	struct pvpanic_instance pi_cur, pi_next;
394febc9	72	struct pvpanic_instance *pi = param;
b3c0f877 MC	73
	74	spin_lock(&pvpanic_lock);
	75	list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
	76	if (pi_cur == pi) {
	77	list_del(&pi_cur->list);
	78	break;
	79	}
	80	}
	81	spin_unlock(&pvpanic_lock);
6861d27c	82	}
394febc9 CJ	83
	84	int devm_pvpanic_probe(struct device dev, struct pvpanic_instance pi)
	85	{
	86	if (!pi \|\| !pi->base)
	87	return -EINVAL;
	88
	89	spin_lock(&pvpanic_lock);
	90	list_add(&pi->list, &pvpanic_list);
	91	spin_unlock(&pvpanic_lock);
	92
a99009bc MC	93	dev_set_drvdata(dev, pi);
a99009bc MC	94
394febc9 CJ	95	return devm_add_action_or_reset(dev, pvpanic_remove, pi);
	96	}
	97	EXPORT_SYMBOL_GPL(devm_pvpanic_probe);
6861d27c	98
b3c0f877	99	static int pvpanic_init(void)
6861d27c	100	{
b3c0f877 MC	101	INIT_LIST_HEAD(&pvpanic_list);
	102	spin_lock_init(&pvpanic_lock);
	103
84b0f12a	104	atomic_notifier_chain_register(&panic_notifier_list, &pvpanic_panic_nb);
b3c0f877 MC	105
b3c0f877 MC	106	return 0;
6861d27c	107	}
33a43041	108	module_init(pvpanic_init);
b3c0f877 MC	109
	110	static void pvpanic_exit(void)
	111	{
84b0f12a	112	atomic_notifier_chain_unregister(&panic_notifier_list, &pvpanic_panic_nb);
b3c0f877 MC	113
b3c0f877 MC	114	}
b3c0f877	115	module_exit(pvpanic_exit);