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1/*
2 * Handle extern requests for shutdown, reboot and sysrq
3 */
4#include <linux/kernel.h>
5#include <linux/err.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
13#include <xen/xen.h>
14#include <xen/xenbus.h>
15#include <xen/grant_table.h>
16#include <xen/events.h>
17#include <xen/hvc-console.h>
18#include <xen/xen-ops.h>
19
20#include <asm/xen/hypercall.h>
21#include <asm/xen/page.h>
22#include <asm/xen/hypervisor.h>
23
24enum shutdown_state {
25 SHUTDOWN_INVALID = -1,
26 SHUTDOWN_POWEROFF = 0,
27 SHUTDOWN_SUSPEND = 2,
28 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
29 report a crash, not be instructed to crash!
30 HALT is the same as POWEROFF, as far as we're concerned. The tools use
31 the distinction when we return the reason code to them. */
32 SHUTDOWN_HALT = 4,
33};
34
35/* Ignore multiple shutdown requests. */
36static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
37
38struct suspend_info {
39 int cancelled;
40 unsigned long arg; /* extra hypercall argument */
41 void (*pre)(void);
42 void (*post)(int cancelled);
43};
44
45static void xen_hvm_post_suspend(int cancelled)
46{
47 xen_arch_hvm_post_suspend(cancelled);
48 gnttab_resume();
49}
50
51static void xen_pre_suspend(void)
52{
53 xen_mm_pin_all();
54 gnttab_suspend();
55 xen_arch_pre_suspend();
56}
57
58static void xen_post_suspend(int cancelled)
59{
60 xen_arch_post_suspend(cancelled);
61 gnttab_resume();
62 xen_mm_unpin_all();
63}
64
65#ifdef CONFIG_HIBERNATE_CALLBACKS
66static int xen_suspend(void *data)
67{
68 struct suspend_info *si = data;
69 int err;
70
71 BUG_ON(!irqs_disabled());
72
73 err = syscore_suspend();
74 if (err) {
75 printk(KERN_ERR "xen_suspend: system core suspend failed: %d\n",
76 err);
77 return err;
78 }
79
80 if (si->pre)
81 si->pre();
82
83 /*
84 * This hypercall returns 1 if suspend was cancelled
85 * or the domain was merely checkpointed, and 0 if it
86 * is resuming in a new domain.
87 */
88 si->cancelled = HYPERVISOR_suspend(si->arg);
89
90 if (si->post)
91 si->post(si->cancelled);
92
93 if (!si->cancelled) {
94 xen_irq_resume();
95 xen_console_resume();
96 xen_timer_resume();
97 }
98
99 syscore_resume();
100
101 return 0;
102}
103
104static void do_suspend(void)
105{
106 int err;
107 struct suspend_info si;
108
109 shutting_down = SHUTDOWN_SUSPEND;
110
111#ifdef CONFIG_PREEMPT
112 /* If the kernel is preemptible, we need to freeze all the processes
113 to prevent them from being in the middle of a pagetable update
114 during suspend. */
115 err = freeze_processes();
116 if (err) {
117 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
118 goto out;
119 }
120#endif
121
122 err = dpm_suspend_start(PMSG_FREEZE);
123 if (err) {
124 printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
125 goto out_thaw;
126 }
127
128 printk(KERN_DEBUG "suspending xenstore...\n");
129 xs_suspend();
130
131 err = dpm_suspend_noirq(PMSG_FREEZE);
132 if (err) {
133 printk(KERN_ERR "dpm_suspend_noirq failed: %d\n", err);
134 goto out_resume;
135 }
136
137 si.cancelled = 1;
138
139 if (xen_hvm_domain()) {
140 si.arg = 0UL;
141 si.pre = NULL;
142 si.post = &xen_hvm_post_suspend;
143 } else {
144 si.arg = virt_to_mfn(xen_start_info);
145 si.pre = &xen_pre_suspend;
146 si.post = &xen_post_suspend;
147 }
148
149 err = stop_machine(xen_suspend, &si, cpumask_of(0));
150
151 dpm_resume_noirq(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
152
153 if (err) {
154 printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
155 si.cancelled = 1;
156 }
157
158out_resume:
159 if (!si.cancelled) {
160 xen_arch_resume();
161 xs_resume();
162 } else
163 xs_suspend_cancel();
164
165 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
166
167 /* Make sure timer events get retriggered on all CPUs */
168 clock_was_set();
169
170out_thaw:
171#ifdef CONFIG_PREEMPT
172 thaw_processes();
173out:
174#endif
175 shutting_down = SHUTDOWN_INVALID;
176}
177#endif /* CONFIG_HIBERNATE_CALLBACKS */
178
179struct shutdown_handler {
180 const char *command;
181 void (*cb)(void);
182};
183
184static void do_poweroff(void)
185{
186 shutting_down = SHUTDOWN_POWEROFF;
187 orderly_poweroff(false);
188}
189
190static void do_reboot(void)
191{
192 shutting_down = SHUTDOWN_POWEROFF; /* ? */
193 ctrl_alt_del();
194}
195
196static void shutdown_handler(struct xenbus_watch *watch,
197 const char **vec, unsigned int len)
198{
199 char *str;
200 struct xenbus_transaction xbt;
201 int err;
202 static struct shutdown_handler handlers[] = {
203 { "poweroff", do_poweroff },
204 { "halt", do_poweroff },
205 { "reboot", do_reboot },
206#ifdef CONFIG_HIBERNATE_CALLBACKS
207 { "suspend", do_suspend },
208#endif
209 {NULL, NULL},
210 };
211 static struct shutdown_handler *handler;
212
213 if (shutting_down != SHUTDOWN_INVALID)
214 return;
215
216 again:
217 err = xenbus_transaction_start(&xbt);
218 if (err)
219 return;
220
221 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
222 /* Ignore read errors and empty reads. */
223 if (XENBUS_IS_ERR_READ(str)) {
224 xenbus_transaction_end(xbt, 1);
225 return;
226 }
227
228 for (handler = &handlers[0]; handler->command; handler++) {
229 if (strcmp(str, handler->command) == 0)
230 break;
231 }
232
233 /* Only acknowledge commands which we are prepared to handle. */
234 if (handler->cb)
235 xenbus_write(xbt, "control", "shutdown", "");
236
237 err = xenbus_transaction_end(xbt, 0);
238 if (err == -EAGAIN) {
239 kfree(str);
240 goto again;
241 }
242
243 if (handler->cb) {
244 handler->cb();
245 } else {
246 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
247 shutting_down = SHUTDOWN_INVALID;
248 }
249
250 kfree(str);
251}
252
253#ifdef CONFIG_MAGIC_SYSRQ
254static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
255 unsigned int len)
256{
257 char sysrq_key = '\0';
258 struct xenbus_transaction xbt;
259 int err;
260
261 again:
262 err = xenbus_transaction_start(&xbt);
263 if (err)
264 return;
265 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
266 printk(KERN_ERR "Unable to read sysrq code in "
267 "control/sysrq\n");
268 xenbus_transaction_end(xbt, 1);
269 return;
270 }
271
272 if (sysrq_key != '\0')
273 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
274
275 err = xenbus_transaction_end(xbt, 0);
276 if (err == -EAGAIN)
277 goto again;
278
279 if (sysrq_key != '\0')
280 handle_sysrq(sysrq_key);
281}
282
283static struct xenbus_watch sysrq_watch = {
284 .node = "control/sysrq",
285 .callback = sysrq_handler
286};
287#endif
288
289static struct xenbus_watch shutdown_watch = {
290 .node = "control/shutdown",
291 .callback = shutdown_handler
292};
293
294static int setup_shutdown_watcher(void)
295{
296 int err;
297
298 err = register_xenbus_watch(&shutdown_watch);
299 if (err) {
300 printk(KERN_ERR "Failed to set shutdown watcher\n");
301 return err;
302 }
303
304#ifdef CONFIG_MAGIC_SYSRQ
305 err = register_xenbus_watch(&sysrq_watch);
306 if (err) {
307 printk(KERN_ERR "Failed to set sysrq watcher\n");
308 return err;
309 }
310#endif
311
312 return 0;
313}
314
315static int shutdown_event(struct notifier_block *notifier,
316 unsigned long event,
317 void *data)
318{
319 setup_shutdown_watcher();
320 return NOTIFY_DONE;
321}
322
323int xen_setup_shutdown_event(void)
324{
325 static struct notifier_block xenstore_notifier = {
326 .notifier_call = shutdown_event
327 };
328
329 if (!xen_domain())
330 return -ENODEV;
331 register_xenstore_notifier(&xenstore_notifier);
332
333 return 0;
334}
335EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
336
337subsys_initcall(xen_setup_shutdown_event);
1/*
2 * Handle extern requests for shutdown, reboot and sysrq
3 */
4
5#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
6
7#include <linux/kernel.h>
8#include <linux/err.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>
16
17#include <xen/xen.h>
18#include <xen/xenbus.h>
19#include <xen/grant_table.h>
20#include <xen/events.h>
21#include <xen/hvc-console.h>
22#include <xen/page.h>
23#include <xen/xen-ops.h>
24
25#include <asm/xen/hypercall.h>
26#include <asm/xen/hypervisor.h>
27
28enum shutdown_state {
29 SHUTDOWN_INVALID = -1,
30 SHUTDOWN_POWEROFF = 0,
31 SHUTDOWN_SUSPEND = 2,
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. */
36 SHUTDOWN_HALT = 4,
37};
38
39/* Ignore multiple shutdown requests. */
40static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
41
42struct suspend_info {
43 int cancelled;
44};
45
46static RAW_NOTIFIER_HEAD(xen_resume_notifier);
47
48void xen_resume_notifier_register(struct notifier_block *nb)
49{
50 raw_notifier_chain_register(&xen_resume_notifier, nb);
51}
52EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
53
54void xen_resume_notifier_unregister(struct notifier_block *nb)
55{
56 raw_notifier_chain_unregister(&xen_resume_notifier, nb);
57}
58EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
59
60#ifdef CONFIG_HIBERNATE_CALLBACKS
61static int xen_suspend(void *data)
62{
63 struct suspend_info *si = data;
64 int err;
65
66 BUG_ON(!irqs_disabled());
67
68 err = syscore_suspend();
69 if (err) {
70 pr_err("%s: system core suspend failed: %d\n", __func__, err);
71 return err;
72 }
73
74 gnttab_suspend();
75 xen_manage_runstate_time(-1);
76 xen_arch_pre_suspend();
77
78 si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
79 ? virt_to_gfn(xen_start_info)
80 : 0);
81
82 xen_arch_post_suspend(si->cancelled);
83 xen_manage_runstate_time(si->cancelled ? 1 : 0);
84 gnttab_resume();
85
86 if (!si->cancelled) {
87 xen_irq_resume();
88 xen_timer_resume();
89 }
90
91 syscore_resume();
92
93 return 0;
94}
95
96static void do_suspend(void)
97{
98 int err;
99 struct suspend_info si;
100
101 shutting_down = SHUTDOWN_SUSPEND;
102
103 err = freeze_processes();
104 if (err) {
105 pr_err("%s: freeze processes failed %d\n", __func__, err);
106 goto out;
107 }
108
109 err = freeze_kernel_threads();
110 if (err) {
111 pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
112 goto out_thaw;
113 }
114
115 err = dpm_suspend_start(PMSG_FREEZE);
116 if (err) {
117 pr_err("%s: dpm_suspend_start %d\n", __func__, err);
118 goto out_thaw;
119 }
120
121 printk(KERN_DEBUG "suspending xenstore...\n");
122 xs_suspend();
123
124 err = dpm_suspend_end(PMSG_FREEZE);
125 if (err) {
126 pr_err("dpm_suspend_end failed: %d\n", err);
127 si.cancelled = 0;
128 goto out_resume;
129 }
130
131 xen_arch_suspend();
132
133 si.cancelled = 1;
134
135 err = stop_machine(xen_suspend, &si, cpumask_of(0));
136
137 /* Resume console as early as possible. */
138 if (!si.cancelled)
139 xen_console_resume();
140
141 raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
142
143 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
144
145 if (err) {
146 pr_err("failed to start xen_suspend: %d\n", err);
147 si.cancelled = 1;
148 }
149
150 xen_arch_resume();
151
152out_resume:
153 if (!si.cancelled)
154 xs_resume();
155 else
156 xs_suspend_cancel();
157
158 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
159
160out_thaw:
161 thaw_processes();
162out:
163 shutting_down = SHUTDOWN_INVALID;
164}
165#endif /* CONFIG_HIBERNATE_CALLBACKS */
166
167struct shutdown_handler {
168#define SHUTDOWN_CMD_SIZE 11
169 const char command[SHUTDOWN_CMD_SIZE];
170 bool flag;
171 void (*cb)(void);
172};
173
174static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
175{
176 switch (code) {
177 case SYS_DOWN:
178 case SYS_HALT:
179 case SYS_POWER_OFF:
180 shutting_down = SHUTDOWN_POWEROFF;
181 default:
182 break;
183 }
184 return NOTIFY_DONE;
185}
186static void do_poweroff(void)
187{
188 switch (system_state) {
189 case SYSTEM_BOOTING:
190 case SYSTEM_SCHEDULING:
191 orderly_poweroff(true);
192 break;
193 case SYSTEM_RUNNING:
194 orderly_poweroff(false);
195 break;
196 default:
197 /* Don't do it when we are halting/rebooting. */
198 pr_info("Ignoring Xen toolstack shutdown.\n");
199 break;
200 }
201}
202
203static void do_reboot(void)
204{
205 shutting_down = SHUTDOWN_POWEROFF; /* ? */
206 ctrl_alt_del();
207}
208
209static struct shutdown_handler shutdown_handlers[] = {
210 { "poweroff", true, do_poweroff },
211 { "halt", false, do_poweroff },
212 { "reboot", true, do_reboot },
213#ifdef CONFIG_HIBERNATE_CALLBACKS
214 { "suspend", true, do_suspend },
215#endif
216};
217
218static void shutdown_handler(struct xenbus_watch *watch,
219 const char *path, const char *token)
220{
221 char *str;
222 struct xenbus_transaction xbt;
223 int err;
224 int idx;
225
226 if (shutting_down != SHUTDOWN_INVALID)
227 return;
228
229 again:
230 err = xenbus_transaction_start(&xbt);
231 if (err)
232 return;
233
234 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
235 /* Ignore read errors and empty reads. */
236 if (XENBUS_IS_ERR_READ(str)) {
237 xenbus_transaction_end(xbt, 1);
238 return;
239 }
240
241 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
242 if (strcmp(str, shutdown_handlers[idx].command) == 0)
243 break;
244 }
245
246 /* Only acknowledge commands which we are prepared to handle. */
247 if (idx < ARRAY_SIZE(shutdown_handlers))
248 xenbus_write(xbt, "control", "shutdown", "");
249
250 err = xenbus_transaction_end(xbt, 0);
251 if (err == -EAGAIN) {
252 kfree(str);
253 goto again;
254 }
255
256 if (idx < ARRAY_SIZE(shutdown_handlers)) {
257 shutdown_handlers[idx].cb();
258 } else {
259 pr_info("Ignoring shutdown request: %s\n", str);
260 shutting_down = SHUTDOWN_INVALID;
261 }
262
263 kfree(str);
264}
265
266#ifdef CONFIG_MAGIC_SYSRQ
267static void sysrq_handler(struct xenbus_watch *watch, const char *path,
268 const char *token)
269{
270 char sysrq_key = '\0';
271 struct xenbus_transaction xbt;
272 int err;
273
274 again:
275 err = xenbus_transaction_start(&xbt);
276 if (err)
277 return;
278 err = xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key);
279 if (err < 0) {
280 /*
281 * The Xenstore watch fires directly after registering it and
282 * after a suspend/resume cycle. So ENOENT is no error but
283 * might happen in those cases.
284 */
285 if (err != -ENOENT)
286 pr_err("Error %d reading sysrq code in control/sysrq\n",
287 err);
288 xenbus_transaction_end(xbt, 1);
289 return;
290 }
291
292 if (sysrq_key != '\0')
293 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
294
295 err = xenbus_transaction_end(xbt, 0);
296 if (err == -EAGAIN)
297 goto again;
298
299 if (sysrq_key != '\0')
300 handle_sysrq(sysrq_key);
301}
302
303static struct xenbus_watch sysrq_watch = {
304 .node = "control/sysrq",
305 .callback = sysrq_handler
306};
307#endif
308
309static struct xenbus_watch shutdown_watch = {
310 .node = "control/shutdown",
311 .callback = shutdown_handler
312};
313
314static struct notifier_block xen_reboot_nb = {
315 .notifier_call = poweroff_nb,
316};
317
318static int setup_shutdown_watcher(void)
319{
320 int err;
321 int idx;
322#define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-"))
323 char node[FEATURE_PATH_SIZE];
324
325 err = register_xenbus_watch(&shutdown_watch);
326 if (err) {
327 pr_err("Failed to set shutdown watcher\n");
328 return err;
329 }
330
331
332#ifdef CONFIG_MAGIC_SYSRQ
333 err = register_xenbus_watch(&sysrq_watch);
334 if (err) {
335 pr_err("Failed to set sysrq watcher\n");
336 return err;
337 }
338#endif
339
340 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
341 if (!shutdown_handlers[idx].flag)
342 continue;
343 snprintf(node, FEATURE_PATH_SIZE, "feature-%s",
344 shutdown_handlers[idx].command);
345 xenbus_printf(XBT_NIL, "control", node, "%u", 1);
346 }
347
348 return 0;
349}
350
351static int shutdown_event(struct notifier_block *notifier,
352 unsigned long event,
353 void *data)
354{
355 setup_shutdown_watcher();
356 return NOTIFY_DONE;
357}
358
359int xen_setup_shutdown_event(void)
360{
361 static struct notifier_block xenstore_notifier = {
362 .notifier_call = shutdown_event
363 };
364
365 if (!xen_domain())
366 return -ENODEV;
367 register_xenstore_notifier(&xenstore_notifier);
368 register_reboot_notifier(&xen_reboot_nb);
369
370 return 0;
371}
372EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
373
374subsys_initcall(xen_setup_shutdown_event);