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>
11 #include <linux/syscore_ops.h>
12 #include <linux/export.h>
15 #include <xen/xenbus.h>
16 #include <xen/grant_table.h>
17 #include <xen/events.h>
18 #include <xen/hvc-console.h>
19 #include <xen/xen-ops.h>
21 #include <asm/xen/hypercall.h>
22 #include <asm/xen/page.h>
23 #include <asm/xen/hypervisor.h>
26 SHUTDOWN_INVALID = -1,
27 SHUTDOWN_POWEROFF = 0,
29 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
30 report a crash, not be instructed to crash!
31 HALT is the same as POWEROFF, as far as we're concerned. The tools use
32 the distinction when we return the reason code to them. */
36 /* Ignore multiple shutdown requests. */
37 static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
41 unsigned long arg; /* extra hypercall argument */
43 void (*post)(int cancelled);
46 static void xen_hvm_post_suspend(int cancelled)
48 xen_arch_hvm_post_suspend(cancelled);
52 static void xen_pre_suspend(void)
56 xen_arch_pre_suspend();
59 static void xen_post_suspend(int cancelled)
61 xen_arch_post_suspend(cancelled);
66 #ifdef CONFIG_HIBERNATE_CALLBACKS
67 static int xen_suspend(void *data)
69 struct suspend_info *si = data;
72 BUG_ON(!irqs_disabled());
74 err = syscore_suspend();
76 printk(KERN_ERR "xen_suspend: system core suspend failed: %d\n",
85 * This hypercall returns 1 if suspend was cancelled
86 * or the domain was merely checkpointed, and 0 if it
87 * is resuming in a new domain.
89 si->cancelled = HYPERVISOR_suspend(si->arg);
92 si->post(si->cancelled);
105 static void do_suspend(void)
108 struct suspend_info si;
110 shutting_down = SHUTDOWN_SUSPEND;
112 #ifdef CONFIG_PREEMPT
113 /* If the kernel is preemptible, we need to freeze all the processes
114 to prevent them from being in the middle of a pagetable update
116 err = freeze_processes();
118 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
123 err = dpm_suspend_start(PMSG_FREEZE);
125 printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
129 printk(KERN_DEBUG "suspending xenstore...\n");
132 err = dpm_suspend_end(PMSG_FREEZE);
134 printk(KERN_ERR "dpm_suspend_end failed: %d\n", err);
141 if (xen_hvm_domain()) {
144 si.post = &xen_hvm_post_suspend;
146 si.arg = virt_to_mfn(xen_start_info);
147 si.pre = &xen_pre_suspend;
148 si.post = &xen_post_suspend;
151 err = stop_machine(xen_suspend, &si, cpumask_of(0));
153 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
156 printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
167 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
170 #ifdef CONFIG_PREEMPT
174 shutting_down = SHUTDOWN_INVALID;
176 #endif /* CONFIG_HIBERNATE_CALLBACKS */
178 struct shutdown_handler {
183 static void do_poweroff(void)
185 shutting_down = SHUTDOWN_POWEROFF;
186 orderly_poweroff(false);
189 static void do_reboot(void)
191 shutting_down = SHUTDOWN_POWEROFF; /* ? */
195 static void shutdown_handler(struct xenbus_watch *watch,
196 const char **vec, unsigned int len)
199 struct xenbus_transaction xbt;
201 static struct shutdown_handler handlers[] = {
202 { "poweroff", do_poweroff },
203 { "halt", do_poweroff },
204 { "reboot", do_reboot },
205 #ifdef CONFIG_HIBERNATE_CALLBACKS
206 { "suspend", do_suspend },
210 static struct shutdown_handler *handler;
212 if (shutting_down != SHUTDOWN_INVALID)
216 err = xenbus_transaction_start(&xbt);
220 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
221 /* Ignore read errors and empty reads. */
222 if (XENBUS_IS_ERR_READ(str)) {
223 xenbus_transaction_end(xbt, 1);
227 for (handler = &handlers[0]; handler->command; handler++) {
228 if (strcmp(str, handler->command) == 0)
232 /* Only acknowledge commands which we are prepared to handle. */
234 xenbus_write(xbt, "control", "shutdown", "");
236 err = xenbus_transaction_end(xbt, 0);
237 if (err == -EAGAIN) {
245 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
246 shutting_down = SHUTDOWN_INVALID;
252 #ifdef CONFIG_MAGIC_SYSRQ
253 static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
256 char sysrq_key = '\0';
257 struct xenbus_transaction xbt;
261 err = xenbus_transaction_start(&xbt);
264 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
265 printk(KERN_ERR "Unable to read sysrq code in "
267 xenbus_transaction_end(xbt, 1);
271 if (sysrq_key != '\0')
272 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
274 err = xenbus_transaction_end(xbt, 0);
278 if (sysrq_key != '\0')
279 handle_sysrq(sysrq_key);
282 static struct xenbus_watch sysrq_watch = {
283 .node = "control/sysrq",
284 .callback = sysrq_handler
288 static struct xenbus_watch shutdown_watch = {
289 .node = "control/shutdown",
290 .callback = shutdown_handler
293 static int setup_shutdown_watcher(void)
297 err = register_xenbus_watch(&shutdown_watch);
299 printk(KERN_ERR "Failed to set shutdown watcher\n");
303 #ifdef CONFIG_MAGIC_SYSRQ
304 err = register_xenbus_watch(&sysrq_watch);
306 printk(KERN_ERR "Failed to set sysrq watcher\n");
314 static int shutdown_event(struct notifier_block *notifier,
318 setup_shutdown_watcher();
322 int xen_setup_shutdown_event(void)
324 static struct notifier_block xenstore_notifier = {
325 .notifier_call = shutdown_event
330 register_xenstore_notifier(&xenstore_notifier);
334 EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
336 subsys_initcall(xen_setup_shutdown_event);