2 * Handle extern requests for shutdown, reboot and sysrq
4 #include <linux/kernel.h>
6 #include <linux/slab.h>
7 #include <linux/reboot.h>
8 #include <linux/sysrq.h>
9 #include <linux/stop_machine.h>
10 #include <linux/freezer.h>
12 #include <xen/xenbus.h>
13 #include <xen/grant_table.h>
14 #include <xen/events.h>
15 #include <xen/hvc-console.h>
16 #include <xen/xen-ops.h>
18 #include <asm/xen/hypercall.h>
19 #include <asm/xen/page.h>
22 SHUTDOWN_INVALID = -1,
23 SHUTDOWN_POWEROFF = 0,
25 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
26 report a crash, not be instructed to crash!
27 HALT is the same as POWEROFF, as far as we're concerned. The tools use
28 the distinction when we return the reason code to them. */
32 /* Ignore multiple shutdown requests. */
33 static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
35 #ifdef CONFIG_PM_SLEEP
36 static int xen_suspend(void *data)
38 int *cancelled = data;
41 BUG_ON(!irqs_disabled());
43 err = sysdev_suspend(PMSG_SUSPEND);
45 printk(KERN_ERR "xen_suspend: sysdev_suspend failed: %d\n",
55 * This hypercall returns 1 if suspend was cancelled
56 * or the domain was merely checkpointed, and 0 if it
57 * is resuming in a new domain.
59 *cancelled = HYPERVISOR_suspend(virt_to_mfn(xen_start_info));
61 xen_post_suspend(*cancelled);
76 static void do_suspend(void)
81 shutting_down = SHUTDOWN_SUSPEND;
84 /* If the kernel is preemptible, we need to freeze all the processes
85 to prevent them from being in the middle of a pagetable update
87 err = freeze_processes();
89 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
94 err = dpm_suspend_start(PMSG_SUSPEND);
96 printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
100 printk(KERN_DEBUG "suspending xenstore...\n");
103 err = dpm_suspend_noirq(PMSG_SUSPEND);
105 printk(KERN_ERR "dpm_suspend_noirq failed: %d\n", err);
109 err = stop_machine(xen_suspend, &cancelled, cpumask_of(0));
111 dpm_resume_noirq(PMSG_RESUME);
114 printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
125 dpm_resume_end(PMSG_RESUME);
127 /* Make sure timer events get retriggered on all CPUs */
131 #ifdef CONFIG_PREEMPT
135 shutting_down = SHUTDOWN_INVALID;
137 #endif /* CONFIG_PM_SLEEP */
139 static void shutdown_handler(struct xenbus_watch *watch,
140 const char **vec, unsigned int len)
143 struct xenbus_transaction xbt;
146 if (shutting_down != SHUTDOWN_INVALID)
150 err = xenbus_transaction_start(&xbt);
154 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
155 /* Ignore read errors and empty reads. */
156 if (XENBUS_IS_ERR_READ(str)) {
157 xenbus_transaction_end(xbt, 1);
161 xenbus_write(xbt, "control", "shutdown", "");
163 err = xenbus_transaction_end(xbt, 0);
164 if (err == -EAGAIN) {
169 if (strcmp(str, "poweroff") == 0 ||
170 strcmp(str, "halt") == 0) {
171 shutting_down = SHUTDOWN_POWEROFF;
172 orderly_poweroff(false);
173 } else if (strcmp(str, "reboot") == 0) {
174 shutting_down = SHUTDOWN_POWEROFF; /* ? */
176 #ifdef CONFIG_PM_SLEEP
177 } else if (strcmp(str, "suspend") == 0) {
181 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
182 shutting_down = SHUTDOWN_INVALID;
188 #ifdef CONFIG_MAGIC_SYSRQ
189 static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
192 char sysrq_key = '\0';
193 struct xenbus_transaction xbt;
197 err = xenbus_transaction_start(&xbt);
200 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
201 printk(KERN_ERR "Unable to read sysrq code in "
203 xenbus_transaction_end(xbt, 1);
207 if (sysrq_key != '\0')
208 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
210 err = xenbus_transaction_end(xbt, 0);
214 if (sysrq_key != '\0')
215 handle_sysrq(sysrq_key, NULL);
218 static struct xenbus_watch sysrq_watch = {
219 .node = "control/sysrq",
220 .callback = sysrq_handler
224 static struct xenbus_watch shutdown_watch = {
225 .node = "control/shutdown",
226 .callback = shutdown_handler
229 static int setup_shutdown_watcher(void)
233 err = register_xenbus_watch(&shutdown_watch);
235 printk(KERN_ERR "Failed to set shutdown watcher\n");
239 #ifdef CONFIG_MAGIC_SYSRQ
240 err = register_xenbus_watch(&sysrq_watch);
242 printk(KERN_ERR "Failed to set sysrq watcher\n");
250 static int shutdown_event(struct notifier_block *notifier,
254 setup_shutdown_watcher();
258 static int __init setup_shutdown_event(void)
260 static struct notifier_block xenstore_notifier = {
261 .notifier_call = shutdown_event
263 register_xenstore_notifier(&xenstore_notifier);
268 subsys_initcall(setup_shutdown_event);