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>
13 #include <xen/xenbus.h>
14 #include <xen/grant_table.h>
15 #include <xen/events.h>
16 #include <xen/hvc-console.h>
17 #include <xen/xen-ops.h>
19 #include <asm/xen/hypercall.h>
20 #include <asm/xen/page.h>
21 #include <asm/xen/hypervisor.h>
24 SHUTDOWN_INVALID = -1,
25 SHUTDOWN_POWEROFF = 0,
27 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
28 report a crash, not be instructed to crash!
29 HALT is the same as POWEROFF, as far as we're concerned. The tools use
30 the distinction when we return the reason code to them. */
34 /* Ignore multiple shutdown requests. */
35 static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
41 #ifdef CONFIG_PM_SLEEP
42 static int xen_hvm_suspend(void *data)
44 struct suspend_info *si = data;
47 BUG_ON(!irqs_disabled());
49 err = sysdev_suspend(PMSG_SUSPEND);
51 printk(KERN_ERR "xen_hvm_suspend: sysdev_suspend failed: %d\n",
57 * This hypercall returns 1 if suspend was cancelled
58 * or the domain was merely checkpointed, and 0 if it
59 * is resuming in a new domain.
61 si->cancelled = HYPERVISOR_suspend(0UL);
63 xen_hvm_post_suspend(si->cancelled);
77 static int xen_suspend(void *data)
79 struct suspend_info *si = data;
82 BUG_ON(!irqs_disabled());
84 err = sysdev_suspend(PMSG_SUSPEND);
86 printk(KERN_ERR "xen_suspend: sysdev_suspend failed: %d\n",
96 * This hypercall returns 1 if suspend was cancelled
97 * or the domain was merely checkpointed, and 0 if it
98 * is resuming in a new domain.
100 si->cancelled = HYPERVISOR_suspend(virt_to_mfn(xen_start_info));
102 xen_post_suspend(si->cancelled);
106 if (!si->cancelled) {
108 xen_console_resume();
117 static void do_suspend(void)
120 struct suspend_info si;
122 shutting_down = SHUTDOWN_SUSPEND;
124 #ifdef CONFIG_PREEMPT
125 /* If the kernel is preemptible, we need to freeze all the processes
126 to prevent them from being in the middle of a pagetable update
128 err = freeze_processes();
130 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
135 err = dpm_suspend_start(PMSG_SUSPEND);
137 printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
141 printk(KERN_DEBUG "suspending xenstore...\n");
144 err = dpm_suspend_noirq(PMSG_SUSPEND);
146 printk(KERN_ERR "dpm_suspend_noirq failed: %d\n", err);
152 if (xen_hvm_domain())
153 err = stop_machine(xen_hvm_suspend, &si, cpumask_of(0));
155 err = stop_machine(xen_suspend, &si, cpumask_of(0));
157 dpm_resume_noirq(PMSG_RESUME);
160 printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
171 dpm_resume_end(PMSG_RESUME);
173 /* Make sure timer events get retriggered on all CPUs */
177 #ifdef CONFIG_PREEMPT
181 shutting_down = SHUTDOWN_INVALID;
183 #endif /* CONFIG_PM_SLEEP */
185 struct shutdown_handler {
190 static void do_poweroff(void)
192 shutting_down = SHUTDOWN_POWEROFF;
193 orderly_poweroff(false);
196 static void do_reboot(void)
198 shutting_down = SHUTDOWN_POWEROFF; /* ? */
202 static void shutdown_handler(struct xenbus_watch *watch,
203 const char **vec, unsigned int len)
206 struct xenbus_transaction xbt;
208 static struct shutdown_handler handlers[] = {
209 { "poweroff", do_poweroff },
210 { "halt", do_poweroff },
211 { "reboot", do_reboot },
212 #ifdef CONFIG_PM_SLEEP
213 { "suspend", do_suspend },
217 static struct shutdown_handler *handler;
219 if (shutting_down != SHUTDOWN_INVALID)
223 err = xenbus_transaction_start(&xbt);
227 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
228 /* Ignore read errors and empty reads. */
229 if (XENBUS_IS_ERR_READ(str)) {
230 xenbus_transaction_end(xbt, 1);
234 for (handler = &handlers[0]; handler->command; handler++) {
235 if (strcmp(str, handler->command) == 0)
239 /* Only acknowledge commands which we are prepared to handle. */
241 xenbus_write(xbt, "control", "shutdown", "");
243 err = xenbus_transaction_end(xbt, 0);
244 if (err == -EAGAIN) {
252 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
253 shutting_down = SHUTDOWN_INVALID;
259 #ifdef CONFIG_MAGIC_SYSRQ
260 static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
263 char sysrq_key = '\0';
264 struct xenbus_transaction xbt;
268 err = xenbus_transaction_start(&xbt);
271 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
272 printk(KERN_ERR "Unable to read sysrq code in "
274 xenbus_transaction_end(xbt, 1);
278 if (sysrq_key != '\0')
279 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
281 err = xenbus_transaction_end(xbt, 0);
285 if (sysrq_key != '\0')
286 handle_sysrq(sysrq_key);
289 static struct xenbus_watch sysrq_watch = {
290 .node = "control/sysrq",
291 .callback = sysrq_handler
295 static struct xenbus_watch shutdown_watch = {
296 .node = "control/shutdown",
297 .callback = shutdown_handler
300 static int setup_shutdown_watcher(void)
304 err = register_xenbus_watch(&shutdown_watch);
306 printk(KERN_ERR "Failed to set shutdown watcher\n");
310 #ifdef CONFIG_MAGIC_SYSRQ
311 err = register_xenbus_watch(&sysrq_watch);
313 printk(KERN_ERR "Failed to set sysrq watcher\n");
321 static int shutdown_event(struct notifier_block *notifier,
325 setup_shutdown_watcher();
329 int xen_setup_shutdown_event(void)
331 static struct notifier_block xenstore_notifier = {
332 .notifier_call = shutdown_event
337 register_xenstore_notifier(&xenstore_notifier);
341 EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
343 subsys_initcall(xen_setup_shutdown_event);