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>
16 #include <linux/panic_notifier.h>
17 #include <linux/types.h>
18 #include <linux/cdev.h>
19 #include <linux/list.h>
20
21 #include <uapi/misc/pvpanic.h>
22
23 #include "pvpanic.h"
24
25 MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
26 MODULE_DESCRIPTION("pvpanic device driver ");
27 MODULE_LICENSE("GPL");
28
29 static struct list_head pvpanic_list;
30 static spinlock_t pvpanic_lock;
31
32 static void
pvpanic_send_event(unsigned int event)33 pvpanic_send_event(unsigned int event)
34 {
35 struct pvpanic_instance *pi_cur;
36
37 if (!spin_trylock(&pvpanic_lock))
38 return;
39
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);
45 }
46
47 static int
pvpanic_panic_notify(struct notifier_block * nb,unsigned long code,void * unused)48 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
49 void *unused)
50 {
51 unsigned int event = PVPANIC_PANICKED;
52
53 if (kexec_crash_loaded())
54 event = PVPANIC_CRASH_LOADED;
55
56 pvpanic_send_event(event);
57
58 return NOTIFY_DONE;
59 }
60
61 /*
62 * Call our notifier very early on panic, deferring the
63 * action taken to the hypervisor.
64 */
65 static struct notifier_block pvpanic_panic_nb = {
66 .notifier_call = pvpanic_panic_notify,
67 .priority = INT_MAX,
68 };
69
pvpanic_remove(void * param)70 static void pvpanic_remove(void *param)
71 {
72 struct pvpanic_instance *pi_cur, *pi_next;
73 struct pvpanic_instance *pi = param;
74
75 spin_lock(&pvpanic_lock);
76 list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
77 if (pi_cur == pi) {
78 list_del(&pi_cur->list);
79 break;
80 }
81 }
82 spin_unlock(&pvpanic_lock);
83 }
84
devm_pvpanic_probe(struct device * dev,struct pvpanic_instance * pi)85 int devm_pvpanic_probe(struct device *dev, struct pvpanic_instance *pi)
86 {
87 if (!pi || !pi->base)
88 return -EINVAL;
89
90 spin_lock(&pvpanic_lock);
91 list_add(&pi->list, &pvpanic_list);
92 spin_unlock(&pvpanic_lock);
93
94 dev_set_drvdata(dev, pi);
95
96 return devm_add_action_or_reset(dev, pvpanic_remove, pi);
97 }
98 EXPORT_SYMBOL_GPL(devm_pvpanic_probe);
99
pvpanic_init(void)100 static int pvpanic_init(void)
101 {
102 INIT_LIST_HEAD(&pvpanic_list);
103 spin_lock_init(&pvpanic_lock);
104
105 atomic_notifier_chain_register(&panic_notifier_list,
106 &pvpanic_panic_nb);
107
108 return 0;
109 }
110
pvpanic_exit(void)111 static void pvpanic_exit(void)
112 {
113 atomic_notifier_chain_unregister(&panic_notifier_list,
114 &pvpanic_panic_nb);
115
116 }
117
118 module_init(pvpanic_init);
119 module_exit(pvpanic_exit);
120