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