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 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 48 pvpanic_panic_notify(struct notifier_block *nb, unsigned long code, void *unused) 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 60 /* 61 * Call our notifier very early on panic, deferring the 62 * action taken to the hypervisor. 63 */ 64 static struct notifier_block pvpanic_panic_nb = { 65 .notifier_call = pvpanic_panic_notify, 66 .priority = INT_MAX, 67 }; 68 69 static void pvpanic_remove(void *param) 70 { 71 struct pvpanic_instance *pi_cur, *pi_next; 72 struct pvpanic_instance *pi = param; 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); 82 } 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 93 dev_set_drvdata(dev, pi); 94 95 return devm_add_action_or_reset(dev, pvpanic_remove, pi); 96 } 97 EXPORT_SYMBOL_GPL(devm_pvpanic_probe); 98 99 static int pvpanic_init(void) 100 { 101 INIT_LIST_HEAD(&pvpanic_list); 102 spin_lock_init(&pvpanic_lock); 103 104 atomic_notifier_chain_register(&panic_notifier_list, &pvpanic_panic_nb); 105 106 return 0; 107 } 108 module_init(pvpanic_init); 109 110 static void pvpanic_exit(void) 111 { 112 atomic_notifier_chain_unregister(&panic_notifier_list, &pvpanic_panic_nb); 113 114 } 115 module_exit(pvpanic_exit); 116