// SPDX-License-Identifier: GPL-2.0+/* *  Pvpanic Device Support * *  Copyright (C) 2013 Fujitsu. *  Copyright (C) 2018 ZTE. *  Copyright (C) 2021 Oracle. */ #include <linux/device.h>#include <linux/errno.h>#include <linux/gfp_types.h>#include <linux/io.h>#include <linux/kexec.h>#include <linux/kstrtox.h>#include <linux/limits.h>#include <linux/list.h>#include <linux/module.h>#include <linux/panic_notifier.h>#include <linux/platform_device.h>#include <linux/reboot.h>#include <linux/spinlock.h>#include <linux/sysfs.h>#include <linux/types.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"); struct pvpanic_instance {	void __iomem *base;	unsigned int capability;	unsigned int events;	struct sys_off_handler *sys_off;	struct list_head list;}; static struct list_head pvpanic_list;static spinlock_t pvpanic_lock; static voidpvpanic_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 intpvpanic_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 int pvpanic_sys_off(struct sys_off_data *data){	pvpanic_send_event(PVPANIC_SHUTDOWN); 	return NOTIFY_DONE;} static void pvpanic_synchronize_sys_off_handler(struct device *dev, struct pvpanic_instance *pi){	/* The kernel core has logic to fall back to system halt if no	 * sys_off_handler is registered.	 * When the pvpanic sys_off_handler is disabled via sysfs the kernel	 * should use that fallback logic, so the handler needs to be unregistered.	 */ 	struct sys_off_handler *sys_off; 	if (!(pi->events & PVPANIC_SHUTDOWN) == !pi->sys_off)		return; 	if (!pi->sys_off) {		sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_LOW,						   pvpanic_sys_off, NULL);		if (IS_ERR(sys_off))			dev_warn(dev, "Could not register sys_off_handler: %pe\n", sys_off);		else			pi->sys_off = sys_off;	} else {		unregister_sys_off_handler(pi->sys_off);		pi->sys_off = NULL;	}} 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); 	unregister_sys_off_handler(pi->sys_off);} static ssize_t capability_show(struct device *dev, struct device_attribute *attr, char *buf){	struct pvpanic_instance *pi = dev_get_drvdata(dev); 	return sysfs_emit(buf, "%x\n", pi->capability);}static DEVICE_ATTR_RO(capability); static ssize_t events_show(struct device *dev, struct device_attribute *attr, char *buf){	struct pvpanic_instance *pi = dev_get_drvdata(dev); 	return sysfs_emit(buf, "%x\n", pi->events);} static ssize_t events_store(struct device *dev, struct device_attribute *attr,			    const char *buf, size_t count){	struct pvpanic_instance *pi = dev_get_drvdata(dev);	unsigned int tmp;	int err; 	err = kstrtouint(buf, 16, &tmp);	if (err)		return err; 	if ((tmp & pi->capability) != tmp)		return -EINVAL; 	pi->events = tmp;	pvpanic_synchronize_sys_off_handler(dev, pi); 	return count;}static DEVICE_ATTR_RW(events); static struct attribute *pvpanic_dev_attrs[] = {	&dev_attr_capability.attr,	&dev_attr_events.attr,	NULL}; static const struct attribute_group pvpanic_dev_group = {	.attrs = pvpanic_dev_attrs,}; const struct attribute_group *pvpanic_dev_groups[] = {	&pvpanic_dev_group,	NULL};EXPORT_SYMBOL_GPL(pvpanic_dev_groups); int devm_pvpanic_probe(struct device *dev, void __iomem *base){	struct pvpanic_instance *pi; 	if (!base)		return -EINVAL; 	pi = devm_kmalloc(dev, sizeof(*pi), GFP_KERNEL);	if (!pi)		return -ENOMEM; 	pi->base = base;	pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED | PVPANIC_SHUTDOWN; 	/* initlize capability by RDPT */	pi->capability &= ioread8(base);	pi->events = pi->capability; 	pi->sys_off = NULL;	pvpanic_synchronize_sys_off_handler(dev, pi); 	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);