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misc/pvpanic: add support for normal shutdowns

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Shutdown requests are normally hardware dependent.
By extending pvpanic to also handle shutdown requests, guests can
submit such requests with an easily implementable and cross-platform
mechanism.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20240412-pvpanic-shutdown-v3-1-c214e9873b3f@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Weißschuh 2024-04-12 08:26:40 +02:00 committed by Greg Kroah-Hartman
parent 11e5e1aba7
commit 7b51b13733
1 changed files with 42 additions and 1 deletions
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43
drivers/misc/pvpanic/pvpanic.c
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@ -19,6 +19,7 @@
#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>
@ -35,6 +36,7 @@ struct pvpanic_instance {
void __iomem *base;
unsigned int capability;
unsigned int events;
struct sys_off_handler *sys_off;
struct list_head list;
};
@ -78,6 +80,39 @@ static struct notifier_block pvpanic_panic_nb = {
.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;
@ -91,6 +126,8 @@ static void pvpanic_remove(void *param)
}
}
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)
@ -123,6 +160,7 @@ static ssize_t events_store(struct device *dev, struct device_attribute *attr,
return -EINVAL;
pi->events = tmp;
pvpanic_synchronize_sys_off_handler(dev, pi);
return count;
}
@ -156,12 +194,15 @@ int devm_pvpanic_probe(struct device *dev, void __iomem *base)
return -ENOMEM;
pi->base = base;
pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
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);