diff options
Diffstat (limited to 'drivers/misc/pvpanic/pvpanic.c')
| -rw-r--r-- | drivers/misc/pvpanic/pvpanic.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/misc/pvpanic/pvpanic.c b/drivers/misc/pvpanic/pvpanic.c new file mode 100644 index 000000000000..17c0eb549463 --- /dev/null +++ b/drivers/misc/pvpanic/pvpanic.c @@ -0,0 +1,232 @@ +// 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/mod_devicetable.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 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 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); |