2 * Handle extern requests for shutdown, reboot and sysrq
5 #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
7 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include <linux/reboot.h>
11 #include <linux/sysrq.h>
12 #include <linux/stop_machine.h>
13 #include <linux/freezer.h>
14 #include <linux/syscore_ops.h>
15 #include <linux/export.h>
18 #include <xen/xenbus.h>
19 #include <xen/grant_table.h>
20 #include <xen/events.h>
21 #include <xen/hvc-console.h>
23 #include <xen/xen-ops.h>
25 #include <asm/xen/hypercall.h>
26 #include <asm/xen/hypervisor.h>
29 SHUTDOWN_INVALID
= -1,
30 SHUTDOWN_POWEROFF
= 0,
32 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
33 report a crash, not be instructed to crash!
34 HALT is the same as POWEROFF, as far as we're concerned. The tools use
35 the distinction when we return the reason code to them. */
39 /* Ignore multiple shutdown requests. */
40 static enum shutdown_state shutting_down
= SHUTDOWN_INVALID
;
46 static RAW_NOTIFIER_HEAD(xen_resume_notifier
);
48 void xen_resume_notifier_register(struct notifier_block
*nb
)
50 raw_notifier_chain_register(&xen_resume_notifier
, nb
);
52 EXPORT_SYMBOL_GPL(xen_resume_notifier_register
);
54 void xen_resume_notifier_unregister(struct notifier_block
*nb
)
56 raw_notifier_chain_unregister(&xen_resume_notifier
, nb
);
58 EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister
);
60 #ifdef CONFIG_HIBERNATE_CALLBACKS
61 static int xen_suspend(void *data
)
63 struct suspend_info
*si
= data
;
66 BUG_ON(!irqs_disabled());
68 err
= syscore_suspend();
70 pr_err("%s: system core suspend failed: %d\n", __func__
, err
);
75 xen_arch_pre_suspend();
78 * This hypercall returns 1 if suspend was cancelled
79 * or the domain was merely checkpointed, and 0 if it
80 * is resuming in a new domain.
82 si
->cancelled
= HYPERVISOR_suspend(xen_pv_domain()
83 ? virt_to_gfn(xen_start_info
)
86 xen_arch_post_suspend(si
->cancelled
);
99 static void do_suspend(void)
102 struct suspend_info si
;
104 shutting_down
= SHUTDOWN_SUSPEND
;
106 err
= freeze_processes();
108 pr_err("%s: freeze processes failed %d\n", __func__
, err
);
112 err
= freeze_kernel_threads();
114 pr_err("%s: freeze kernel threads failed %d\n", __func__
, err
);
118 err
= dpm_suspend_start(PMSG_FREEZE
);
120 pr_err("%s: dpm_suspend_start %d\n", __func__
, err
);
124 printk(KERN_DEBUG
"suspending xenstore...\n");
127 err
= dpm_suspend_end(PMSG_FREEZE
);
129 pr_err("dpm_suspend_end failed: %d\n", err
);
138 err
= stop_machine(xen_suspend
, &si
, cpumask_of(0));
140 /* Resume console as early as possible. */
142 xen_console_resume();
144 raw_notifier_call_chain(&xen_resume_notifier
, 0, NULL
);
146 dpm_resume_start(si
.cancelled
? PMSG_THAW
: PMSG_RESTORE
);
149 pr_err("failed to start xen_suspend: %d\n", err
);
161 dpm_resume_end(si
.cancelled
? PMSG_THAW
: PMSG_RESTORE
);
166 shutting_down
= SHUTDOWN_INVALID
;
168 #endif /* CONFIG_HIBERNATE_CALLBACKS */
170 struct shutdown_handler
{
171 #define SHUTDOWN_CMD_SIZE 11
172 const char command
[SHUTDOWN_CMD_SIZE
];
177 static int poweroff_nb(struct notifier_block
*cb
, unsigned long code
, void *unused
)
183 shutting_down
= SHUTDOWN_POWEROFF
;
189 static void do_poweroff(void)
191 switch (system_state
) {
193 orderly_poweroff(true);
196 orderly_poweroff(false);
199 /* Don't do it when we are halting/rebooting. */
200 pr_info("Ignoring Xen toolstack shutdown.\n");
205 static void do_reboot(void)
207 shutting_down
= SHUTDOWN_POWEROFF
; /* ? */
211 static struct shutdown_handler shutdown_handlers
[] = {
212 { "poweroff", true, do_poweroff
},
213 { "halt", false, do_poweroff
},
214 { "reboot", true, do_reboot
},
215 #ifdef CONFIG_HIBERNATE_CALLBACKS
216 { "suspend", true, do_suspend
},
220 static void shutdown_handler(struct xenbus_watch
*watch
,
221 const char *path
, const char *token
)
224 struct xenbus_transaction xbt
;
228 if (shutting_down
!= SHUTDOWN_INVALID
)
232 err
= xenbus_transaction_start(&xbt
);
236 str
= (char *)xenbus_read(xbt
, "control", "shutdown", NULL
);
237 /* Ignore read errors and empty reads. */
238 if (XENBUS_IS_ERR_READ(str
)) {
239 xenbus_transaction_end(xbt
, 1);
243 for (idx
= 0; idx
< ARRAY_SIZE(shutdown_handlers
); idx
++) {
244 if (strcmp(str
, shutdown_handlers
[idx
].command
) == 0)
248 /* Only acknowledge commands which we are prepared to handle. */
249 if (idx
< ARRAY_SIZE(shutdown_handlers
))
250 xenbus_write(xbt
, "control", "shutdown", "");
252 err
= xenbus_transaction_end(xbt
, 0);
253 if (err
== -EAGAIN
) {
258 if (idx
< ARRAY_SIZE(shutdown_handlers
)) {
259 shutdown_handlers
[idx
].cb();
261 pr_info("Ignoring shutdown request: %s\n", str
);
262 shutting_down
= SHUTDOWN_INVALID
;
268 #ifdef CONFIG_MAGIC_SYSRQ
269 static void sysrq_handler(struct xenbus_watch
*watch
, const char *path
,
272 char sysrq_key
= '\0';
273 struct xenbus_transaction xbt
;
277 err
= xenbus_transaction_start(&xbt
);
280 if (xenbus_scanf(xbt
, "control", "sysrq", "%c", &sysrq_key
) < 0) {
281 pr_err("Unable to read sysrq code in control/sysrq\n");
282 xenbus_transaction_end(xbt
, 1);
286 if (sysrq_key
!= '\0')
287 xenbus_printf(xbt
, "control", "sysrq", "%c", '\0');
289 err
= xenbus_transaction_end(xbt
, 0);
293 if (sysrq_key
!= '\0')
294 handle_sysrq(sysrq_key
);
297 static struct xenbus_watch sysrq_watch
= {
298 .node
= "control/sysrq",
299 .callback
= sysrq_handler
303 static struct xenbus_watch shutdown_watch
= {
304 .node
= "control/shutdown",
305 .callback
= shutdown_handler
308 static struct notifier_block xen_reboot_nb
= {
309 .notifier_call
= poweroff_nb
,
312 static int setup_shutdown_watcher(void)
316 #define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-"))
317 char node
[FEATURE_PATH_SIZE
];
319 err
= register_xenbus_watch(&shutdown_watch
);
321 pr_err("Failed to set shutdown watcher\n");
326 #ifdef CONFIG_MAGIC_SYSRQ
327 err
= register_xenbus_watch(&sysrq_watch
);
329 pr_err("Failed to set sysrq watcher\n");
334 for (idx
= 0; idx
< ARRAY_SIZE(shutdown_handlers
); idx
++) {
335 if (!shutdown_handlers
[idx
].flag
)
337 snprintf(node
, FEATURE_PATH_SIZE
, "feature-%s",
338 shutdown_handlers
[idx
].command
);
339 xenbus_printf(XBT_NIL
, "control", node
, "%u", 1);
345 static int shutdown_event(struct notifier_block
*notifier
,
349 setup_shutdown_watcher();
353 int xen_setup_shutdown_event(void)
355 static struct notifier_block xenstore_notifier
= {
356 .notifier_call
= shutdown_event
361 register_xenstore_notifier(&xenstore_notifier
);
362 register_reboot_notifier(&xen_reboot_nb
);
366 EXPORT_SYMBOL_GPL(xen_setup_shutdown_event
);
368 subsys_initcall(xen_setup_shutdown_event
);