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Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -07001/*
2 * Handle extern requests for shutdown, reboot and sysrq
3 */
4#include <linux/kernel.h>
5#include <linux/err.h>
6#include <linux/reboot.h>
7#include <linux/sysrq.h>
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +01008#include <linux/stop_machine.h>
9#include <linux/freezer.h>
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -070010
11#include <xen/xenbus.h>
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010012#include <xen/grant_table.h>
13#include <xen/events.h>
14#include <xen/hvc-console.h>
15#include <xen/xen-ops.h>
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -070016
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010017#include <asm/xen/hypercall.h>
18#include <asm/xen/page.h>
19
20enum shutdown_state {
21 SHUTDOWN_INVALID = -1,
22 SHUTDOWN_POWEROFF = 0,
23 SHUTDOWN_SUSPEND = 2,
24 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
25 report a crash, not be instructed to crash!
26 HALT is the same as POWEROFF, as far as we're concerned. The tools use
27 the distinction when we return the reason code to them. */
28 SHUTDOWN_HALT = 4,
29};
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -070030
31/* Ignore multiple shutdown requests. */
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010032static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
33
Jeremy Fitzhardingec7827722008-05-29 09:02:19 +010034#ifdef CONFIG_PM_SLEEP
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010035static int xen_suspend(void *data)
36{
37 int *cancelled = data;
Jeremy Fitzhardinge359cdd32008-05-26 23:31:28 +010038 int err;
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010039
40 BUG_ON(!irqs_disabled());
41
Rafael J. Wysocki770824b2009-02-22 18:38:50 +010042 err = sysdev_suspend(PMSG_SUSPEND);
43 if (err) {
44 printk(KERN_ERR "xen_suspend: sysdev_suspend failed: %d\n",
45 err);
46 device_power_up(PMSG_RESUME);
47 return err;
48 }
Jeremy Fitzhardinge359cdd32008-05-26 23:31:28 +010049
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010050 xen_mm_pin_all();
51 gnttab_suspend();
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010052 xen_pre_suspend();
53
54 /*
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.
58 */
59 *cancelled = HYPERVISOR_suspend(virt_to_mfn(xen_start_info));
60
61 xen_post_suspend(*cancelled);
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010062 gnttab_resume();
63 xen_mm_unpin_all();
64
65 if (!*cancelled) {
66 xen_irq_resume();
67 xen_console_resume();
Isaku Yamahataad55db92008-07-08 15:06:32 -070068 xen_timer_resume();
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010069 }
70
Ian Campbell9a5a2ca2009-03-25 17:46:42 +000071 sysdev_resume();
72 device_power_up(PMSG_RESUME);
73
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +010074 return 0;
75}
76
77static void do_suspend(void)
78{
79 int err;
80 int cancelled = 1;
81
82 shutting_down = SHUTDOWN_SUSPEND;
83
84#ifdef CONFIG_PREEMPT
85 /* If the kernel is preemptible, we need to freeze all the processes
86 to prevent them from being in the middle of a pagetable update
87 during suspend. */
88 err = freeze_processes();
89 if (err) {
90 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
91 return;
92 }
93#endif
94
95 err = device_suspend(PMSG_SUSPEND);
96 if (err) {
97 printk(KERN_ERR "xen suspend: device_suspend %d\n", err);
98 goto out;
99 }
100
101 printk("suspending xenbus...\n");
102 /* XXX use normal device tree? */
103 xenbus_suspend();
104
Rafael J. Wysocki2ed8d2b2009-03-16 22:34:06 +0100105 err = device_power_down(PMSG_SUSPEND);
106 if (err) {
107 printk(KERN_ERR "device_power_down failed: %d\n", err);
108 goto resume_devices;
109 }
110
Rusty Russellf7df8ed2009-01-10 21:58:09 -0800111 err = stop_machine(xen_suspend, &cancelled, cpumask_of(0));
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100112 if (err) {
113 printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
114 goto out;
115 }
116
Isaku Yamahataad55db92008-07-08 15:06:32 -0700117 if (!cancelled) {
118 xen_arch_resume();
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100119 xenbus_resume();
Isaku Yamahataad55db92008-07-08 15:06:32 -0700120 } else
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100121 xenbus_suspend_cancel();
122
Rafael J. Wysocki2ed8d2b2009-03-16 22:34:06 +0100123 device_power_up(PMSG_RESUME);
124
125resume_devices:
Stephen Rothwell55ca0892008-07-17 13:09:24 +1000126 device_resume(PMSG_RESUME);
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100127
Jeremy Fitzhardinge359cdd32008-05-26 23:31:28 +0100128 /* Make sure timer events get retriggered on all CPUs */
129 clock_was_set();
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100130out:
131#ifdef CONFIG_PREEMPT
132 thaw_processes();
133#endif
134 shutting_down = SHUTDOWN_INVALID;
135}
Jeremy Fitzhardingec7827722008-05-29 09:02:19 +0100136#endif /* CONFIG_PM_SLEEP */
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -0700137
138static void shutdown_handler(struct xenbus_watch *watch,
139 const char **vec, unsigned int len)
140{
141 char *str;
142 struct xenbus_transaction xbt;
143 int err;
144
145 if (shutting_down != SHUTDOWN_INVALID)
146 return;
147
148 again:
149 err = xenbus_transaction_start(&xbt);
150 if (err)
151 return;
152
153 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
154 /* Ignore read errors and empty reads. */
155 if (XENBUS_IS_ERR_READ(str)) {
156 xenbus_transaction_end(xbt, 1);
157 return;
158 }
159
160 xenbus_write(xbt, "control", "shutdown", "");
161
162 err = xenbus_transaction_end(xbt, 0);
163 if (err == -EAGAIN) {
164 kfree(str);
165 goto again;
166 }
167
168 if (strcmp(str, "poweroff") == 0 ||
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100169 strcmp(str, "halt") == 0) {
170 shutting_down = SHUTDOWN_POWEROFF;
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -0700171 orderly_poweroff(false);
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100172 } else if (strcmp(str, "reboot") == 0) {
173 shutting_down = SHUTDOWN_POWEROFF; /* ? */
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -0700174 ctrl_alt_del();
Jeremy Fitzhardinge0e913982008-05-26 23:31:27 +0100175#ifdef CONFIG_PM_SLEEP
176 } else if (strcmp(str, "suspend") == 0) {
177 do_suspend();
178#endif
179 } else {
Jeremy Fitzhardinge3e2b8fb2007-07-17 18:37:07 -0700180 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
181 shutting_down = SHUTDOWN_INVALID;
182 }
183
184 kfree(str);
185}
186
187static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
188 unsigned int len)
189{
190 char sysrq_key = '\0';
191 struct xenbus_transaction xbt;
192 int err;
193
194 again:
195 err = xenbus_transaction_start(&xbt);
196 if (err)
197 return;
198 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
199 printk(KERN_ERR "Unable to read sysrq code in "
200 "control/sysrq\n");
201 xenbus_transaction_end(xbt, 1);
202 return;
203 }
204
205 if (sysrq_key != '\0')
206 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
207
208 err = xenbus_transaction_end(xbt, 0);
209 if (err == -EAGAIN)
210 goto again;
211
212 if (sysrq_key != '\0')
213 handle_sysrq(sysrq_key, NULL);
214}
215
216static struct xenbus_watch shutdown_watch = {
217 .node = "control/shutdown",
218 .callback = shutdown_handler
219};
220
221static struct xenbus_watch sysrq_watch = {
222 .node = "control/sysrq",
223 .callback = sysrq_handler
224};
225
226static int setup_shutdown_watcher(void)
227{
228 int err;
229
230 err = register_xenbus_watch(&shutdown_watch);
231 if (err) {
232 printk(KERN_ERR "Failed to set shutdown watcher\n");
233 return err;
234 }
235
236 err = register_xenbus_watch(&sysrq_watch);
237 if (err) {
238 printk(KERN_ERR "Failed to set sysrq watcher\n");
239 return err;
240 }
241
242 return 0;
243}
244
245static int shutdown_event(struct notifier_block *notifier,
246 unsigned long event,
247 void *data)
248{
249 setup_shutdown_watcher();
250 return NOTIFY_DONE;
251}
252
253static int __init setup_shutdown_event(void)
254{
255 static struct notifier_block xenstore_notifier = {
256 .notifier_call = shutdown_event
257 };
258 register_xenstore_notifier(&xenstore_notifier);
259
260 return 0;
261}
262
263subsys_initcall(setup_shutdown_event);