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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Handle extern requests for shutdown, reboot and sysrq
4 */
5
6#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
7
8#include <linux/kernel.h>
9#include <linux/err.h>
10#include <linux/slab.h>
11#include <linux/reboot.h>
12#include <linux/sysrq.h>
13#include <linux/stop_machine.h>
14#include <linux/freezer.h>
15#include <linux/syscore_ops.h>
16#include <linux/export.h>
17
18#include <xen/xen.h>
19#include <xen/xenbus.h>
20#include <xen/grant_table.h>
21#include <xen/events.h>
22#include <xen/hvc-console.h>
23#include <xen/page.h>
24#include <xen/xen-ops.h>
25
26#include <asm/xen/hypercall.h>
27#include <asm/xen/hypervisor.h>
28
29enum shutdown_state {
30 SHUTDOWN_INVALID = -1,
31 SHUTDOWN_POWEROFF = 0,
32 SHUTDOWN_SUSPEND = 2,
33 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
34 report a crash, not be instructed to crash!
35 HALT is the same as POWEROFF, as far as we're concerned. The tools use
36 the distinction when we return the reason code to them. */
37 SHUTDOWN_HALT = 4,
38};
39
40/* Ignore multiple shutdown requests. */
41static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
42
43struct suspend_info {
44 int cancelled;
45};
46
47static RAW_NOTIFIER_HEAD(xen_resume_notifier);
48
49void xen_resume_notifier_register(struct notifier_block *nb)
50{
51 raw_notifier_chain_register(&xen_resume_notifier, nb);
52}
53EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
54
55void xen_resume_notifier_unregister(struct notifier_block *nb)
56{
57 raw_notifier_chain_unregister(&xen_resume_notifier, nb);
58}
59EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
60
61#ifdef CONFIG_HIBERNATE_CALLBACKS
62static int xen_suspend(void *data)
63{
64 struct suspend_info *si = data;
65 int err;
66
67 BUG_ON(!irqs_disabled());
68
69 err = syscore_suspend();
70 if (err) {
71 pr_err("%s: system core suspend failed: %d\n", __func__, err);
72 return err;
73 }
74
75 gnttab_suspend();
76 xen_manage_runstate_time(-1);
77 xen_arch_pre_suspend();
78
79 si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
80 ? virt_to_gfn(xen_start_info)
81 : 0);
82
83 xen_arch_post_suspend(si->cancelled);
84 xen_manage_runstate_time(si->cancelled ? 1 : 0);
85 gnttab_resume();
86
87 if (!si->cancelled) {
88 xen_irq_resume();
89 xen_timer_resume();
90 }
91
92 syscore_resume();
93
94 return 0;
95}
96
97static void do_suspend(void)
98{
99 int err;
100 struct suspend_info si;
101
102 shutting_down = SHUTDOWN_SUSPEND;
103
104 err = freeze_processes();
105 if (err) {
106 pr_err("%s: freeze processes failed %d\n", __func__, err);
107 goto out;
108 }
109
110 err = freeze_kernel_threads();
111 if (err) {
112 pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
113 goto out_thaw;
114 }
115
116 err = dpm_suspend_start(PMSG_FREEZE);
117 if (err) {
118 pr_err("%s: dpm_suspend_start %d\n", __func__, err);
119 goto out_thaw;
120 }
121
122 printk(KERN_DEBUG "suspending xenstore...\n");
123 xs_suspend();
124
125 err = dpm_suspend_end(PMSG_FREEZE);
126 if (err) {
127 pr_err("dpm_suspend_end failed: %d\n", err);
128 si.cancelled = 0;
129 goto out_resume;
130 }
131
132 xen_arch_suspend();
133
134 si.cancelled = 1;
135
136 err = stop_machine(xen_suspend, &si, cpumask_of(0));
137
138 /* Resume console as early as possible. */
139 if (!si.cancelled)
140 xen_console_resume();
141
142 raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
143
144 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
145
146 if (err) {
147 pr_err("failed to start xen_suspend: %d\n", err);
148 si.cancelled = 1;
149 }
150
151 xen_arch_resume();
152
153out_resume:
154 if (!si.cancelled)
155 xs_resume();
156 else
157 xs_suspend_cancel();
158
159 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
160
161out_thaw:
162 thaw_processes();
163out:
164 shutting_down = SHUTDOWN_INVALID;
165}
166#endif /* CONFIG_HIBERNATE_CALLBACKS */
167
168struct shutdown_handler {
169#define SHUTDOWN_CMD_SIZE 11
170 const char command[SHUTDOWN_CMD_SIZE];
171 bool flag;
172 void (*cb)(void);
173};
174
175static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
176{
177 switch (code) {
178 case SYS_DOWN:
179 case SYS_HALT:
180 case SYS_POWER_OFF:
181 shutting_down = SHUTDOWN_POWEROFF;
182 default:
183 break;
184 }
185 return NOTIFY_DONE;
186}
187static void do_poweroff(void)
188{
189 switch (system_state) {
190 case SYSTEM_BOOTING:
191 case SYSTEM_SCHEDULING:
192 orderly_poweroff(true);
193 break;
194 case SYSTEM_RUNNING:
195 orderly_poweroff(false);
196 break;
197 default:
198 /* Don't do it when we are halting/rebooting. */
199 pr_info("Ignoring Xen toolstack shutdown.\n");
200 break;
201 }
202}
203
204static void do_reboot(void)
205{
206 shutting_down = SHUTDOWN_POWEROFF; /* ? */
207 ctrl_alt_del();
208}
209
210static struct shutdown_handler shutdown_handlers[] = {
211 { "poweroff", true, do_poweroff },
212 { "halt", false, do_poweroff },
213 { "reboot", true, do_reboot },
214#ifdef CONFIG_HIBERNATE_CALLBACKS
215 { "suspend", true, do_suspend },
216#endif
217};
218
219static void shutdown_handler(struct xenbus_watch *watch,
220 const char *path, const char *token)
221{
222 char *str;
223 struct xenbus_transaction xbt;
224 int err;
225 int idx;
226
227 if (shutting_down != SHUTDOWN_INVALID)
228 return;
229
230 again:
231 err = xenbus_transaction_start(&xbt);
232 if (err)
233 return;
234
235 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
236 /* Ignore read errors and empty reads. */
237 if (XENBUS_IS_ERR_READ(str)) {
238 xenbus_transaction_end(xbt, 1);
239 return;
240 }
241
242 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
243 if (strcmp(str, shutdown_handlers[idx].command) == 0)
244 break;
245 }
246
247 /* Only acknowledge commands which we are prepared to handle. */
248 if (idx < ARRAY_SIZE(shutdown_handlers))
249 xenbus_write(xbt, "control", "shutdown", "");
250
251 err = xenbus_transaction_end(xbt, 0);
252 if (err == -EAGAIN) {
253 kfree(str);
254 goto again;
255 }
256
257 if (idx < ARRAY_SIZE(shutdown_handlers)) {
258 shutdown_handlers[idx].cb();
259 } else {
260 pr_info("Ignoring shutdown request: %s\n", str);
261 shutting_down = SHUTDOWN_INVALID;
262 }
263
264 kfree(str);
265}
266
267#ifdef CONFIG_MAGIC_SYSRQ
268static void sysrq_handler(struct xenbus_watch *watch, const char *path,
269 const char *token)
270{
271 char sysrq_key = '\0';
272 struct xenbus_transaction xbt;
273 int err;
274
275 again:
276 err = xenbus_transaction_start(&xbt);
277 if (err)
278 return;
279 err = xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key);
280 if (err < 0) {
281 /*
282 * The Xenstore watch fires directly after registering it and
283 * after a suspend/resume cycle. So ENOENT is no error but
284 * might happen in those cases. ERANGE is observed when we get
285 * an empty value (''), this happens when we acknowledge the
286 * request by writing '\0' below.
287 */
288 if (err != -ENOENT && err != -ERANGE)
289 pr_err("Error %d reading sysrq code in control/sysrq\n",
290 err);
291 xenbus_transaction_end(xbt, 1);
292 return;
293 }
294
295 if (sysrq_key != '\0') {
296 err = xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
297 if (err) {
298 pr_err("%s: Error %d writing sysrq in control/sysrq\n",
299 __func__, err);
300 xenbus_transaction_end(xbt, 1);
301 return;
302 }
303 }
304
305 err = xenbus_transaction_end(xbt, 0);
306 if (err == -EAGAIN)
307 goto again;
308
309 if (sysrq_key != '\0')
310 handle_sysrq(sysrq_key);
311}
312
313static struct xenbus_watch sysrq_watch = {
314 .node = "control/sysrq",
315 .callback = sysrq_handler
316};
317#endif
318
319static struct xenbus_watch shutdown_watch = {
320 .node = "control/shutdown",
321 .callback = shutdown_handler
322};
323
324static struct notifier_block xen_reboot_nb = {
325 .notifier_call = poweroff_nb,
326};
327
328static int setup_shutdown_watcher(void)
329{
330 int err;
331 int idx;
332#define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-"))
333 char node[FEATURE_PATH_SIZE];
334
335 err = register_xenbus_watch(&shutdown_watch);
336 if (err) {
337 pr_err("Failed to set shutdown watcher\n");
338 return err;
339 }
340
341
342#ifdef CONFIG_MAGIC_SYSRQ
343 err = register_xenbus_watch(&sysrq_watch);
344 if (err) {
345 pr_err("Failed to set sysrq watcher\n");
346 return err;
347 }
348#endif
349
350 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
351 if (!shutdown_handlers[idx].flag)
352 continue;
353 snprintf(node, FEATURE_PATH_SIZE, "feature-%s",
354 shutdown_handlers[idx].command);
355 err = xenbus_printf(XBT_NIL, "control", node, "%u", 1);
356 if (err) {
357 pr_err("%s: Error %d writing %s\n", __func__,
358 err, node);
359 return err;
360 }
361 }
362
363 return 0;
364}
365
366static int shutdown_event(struct notifier_block *notifier,
367 unsigned long event,
368 void *data)
369{
370 setup_shutdown_watcher();
371 return NOTIFY_DONE;
372}
373
374int xen_setup_shutdown_event(void)
375{
376 static struct notifier_block xenstore_notifier = {
377 .notifier_call = shutdown_event
378 };
379
380 if (!xen_domain())
381 return -ENODEV;
382 register_xenstore_notifier(&xenstore_notifier);
383 register_reboot_notifier(&xen_reboot_nb);
384
385 return 0;
386}
387EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
388
389subsys_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/xen-ops.h>
23
24#include <asm/xen/hypercall.h>
25#include <asm/xen/page.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 unsigned long arg; /* extra hypercall argument */
45 void (*pre)(void);
46 void (*post)(int cancelled);
47};
48
49static RAW_NOTIFIER_HEAD(xen_resume_notifier);
50
51void xen_resume_notifier_register(struct notifier_block *nb)
52{
53 raw_notifier_chain_register(&xen_resume_notifier, nb);
54}
55EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
56
57void xen_resume_notifier_unregister(struct notifier_block *nb)
58{
59 raw_notifier_chain_unregister(&xen_resume_notifier, nb);
60}
61EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
62
63#ifdef CONFIG_HIBERNATE_CALLBACKS
64static void xen_hvm_post_suspend(int cancelled)
65{
66 xen_arch_hvm_post_suspend(cancelled);
67 gnttab_resume();
68}
69
70static void xen_pre_suspend(void)
71{
72 xen_mm_pin_all();
73 gnttab_suspend();
74 xen_arch_pre_suspend();
75}
76
77static void xen_post_suspend(int cancelled)
78{
79 xen_arch_post_suspend(cancelled);
80 gnttab_resume();
81 xen_mm_unpin_all();
82}
83
84static int xen_suspend(void *data)
85{
86 struct suspend_info *si = data;
87 int err;
88
89 BUG_ON(!irqs_disabled());
90
91 err = syscore_suspend();
92 if (err) {
93 pr_err("%s: system core suspend failed: %d\n", __func__, err);
94 return err;
95 }
96
97 if (si->pre)
98 si->pre();
99
100 /*
101 * This hypercall returns 1 if suspend was cancelled
102 * or the domain was merely checkpointed, and 0 if it
103 * is resuming in a new domain.
104 */
105 si->cancelled = HYPERVISOR_suspend(si->arg);
106
107 if (si->post)
108 si->post(si->cancelled);
109
110 if (!si->cancelled) {
111 xen_irq_resume();
112 xen_console_resume();
113 xen_timer_resume();
114 }
115
116 syscore_resume();
117
118 return 0;
119}
120
121static void do_suspend(void)
122{
123 int err;
124 struct suspend_info si;
125
126 shutting_down = SHUTDOWN_SUSPEND;
127
128#ifdef CONFIG_PREEMPT
129 /* If the kernel is preemptible, we need to freeze all the processes
130 to prevent them from being in the middle of a pagetable update
131 during suspend. */
132 err = freeze_processes();
133 if (err) {
134 pr_err("%s: freeze failed %d\n", __func__, err);
135 goto out;
136 }
137#endif
138
139 err = dpm_suspend_start(PMSG_FREEZE);
140 if (err) {
141 pr_err("%s: dpm_suspend_start %d\n", __func__, err);
142 goto out_thaw;
143 }
144
145 printk(KERN_DEBUG "suspending xenstore...\n");
146 xs_suspend();
147
148 err = dpm_suspend_end(PMSG_FREEZE);
149 if (err) {
150 pr_err("dpm_suspend_end failed: %d\n", err);
151 si.cancelled = 0;
152 goto out_resume;
153 }
154
155 si.cancelled = 1;
156
157 if (xen_hvm_domain()) {
158 si.arg = 0UL;
159 si.pre = NULL;
160 si.post = &xen_hvm_post_suspend;
161 } else {
162 si.arg = virt_to_mfn(xen_start_info);
163 si.pre = &xen_pre_suspend;
164 si.post = &xen_post_suspend;
165 }
166
167 err = stop_machine(xen_suspend, &si, cpumask_of(0));
168
169 raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
170
171 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
172
173 if (err) {
174 pr_err("failed to start xen_suspend: %d\n", err);
175 si.cancelled = 1;
176 }
177
178out_resume:
179 if (!si.cancelled) {
180 xen_arch_resume();
181 xs_resume();
182 } else
183 xs_suspend_cancel();
184
185 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
186
187out_thaw:
188#ifdef CONFIG_PREEMPT
189 thaw_processes();
190out:
191#endif
192 shutting_down = SHUTDOWN_INVALID;
193}
194#endif /* CONFIG_HIBERNATE_CALLBACKS */
195
196struct shutdown_handler {
197 const char *command;
198 void (*cb)(void);
199};
200
201static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
202{
203 switch (code) {
204 case SYS_DOWN:
205 case SYS_HALT:
206 case SYS_POWER_OFF:
207 shutting_down = SHUTDOWN_POWEROFF;
208 default:
209 break;
210 }
211 return NOTIFY_DONE;
212}
213static void do_poweroff(void)
214{
215 switch (system_state) {
216 case SYSTEM_BOOTING:
217 orderly_poweroff(true);
218 break;
219 case SYSTEM_RUNNING:
220 orderly_poweroff(false);
221 break;
222 default:
223 /* Don't do it when we are halting/rebooting. */
224 pr_info("Ignoring Xen toolstack shutdown.\n");
225 break;
226 }
227}
228
229static void do_reboot(void)
230{
231 shutting_down = SHUTDOWN_POWEROFF; /* ? */
232 ctrl_alt_del();
233}
234
235static void shutdown_handler(struct xenbus_watch *watch,
236 const char **vec, unsigned int len)
237{
238 char *str;
239 struct xenbus_transaction xbt;
240 int err;
241 static struct shutdown_handler handlers[] = {
242 { "poweroff", do_poweroff },
243 { "halt", do_poweroff },
244 { "reboot", do_reboot },
245#ifdef CONFIG_HIBERNATE_CALLBACKS
246 { "suspend", do_suspend },
247#endif
248 {NULL, NULL},
249 };
250 static struct shutdown_handler *handler;
251
252 if (shutting_down != SHUTDOWN_INVALID)
253 return;
254
255 again:
256 err = xenbus_transaction_start(&xbt);
257 if (err)
258 return;
259
260 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
261 /* Ignore read errors and empty reads. */
262 if (XENBUS_IS_ERR_READ(str)) {
263 xenbus_transaction_end(xbt, 1);
264 return;
265 }
266
267 for (handler = &handlers[0]; handler->command; handler++) {
268 if (strcmp(str, handler->command) == 0)
269 break;
270 }
271
272 /* Only acknowledge commands which we are prepared to handle. */
273 if (handler->cb)
274 xenbus_write(xbt, "control", "shutdown", "");
275
276 err = xenbus_transaction_end(xbt, 0);
277 if (err == -EAGAIN) {
278 kfree(str);
279 goto again;
280 }
281
282 if (handler->cb) {
283 handler->cb();
284 } else {
285 pr_info("Ignoring shutdown request: %s\n", str);
286 shutting_down = SHUTDOWN_INVALID;
287 }
288
289 kfree(str);
290}
291
292#ifdef CONFIG_MAGIC_SYSRQ
293static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
294 unsigned int len)
295{
296 char sysrq_key = '\0';
297 struct xenbus_transaction xbt;
298 int err;
299
300 again:
301 err = xenbus_transaction_start(&xbt);
302 if (err)
303 return;
304 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
305 pr_err("Unable to read sysrq code in control/sysrq\n");
306 xenbus_transaction_end(xbt, 1);
307 return;
308 }
309
310 if (sysrq_key != '\0')
311 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
312
313 err = xenbus_transaction_end(xbt, 0);
314 if (err == -EAGAIN)
315 goto again;
316
317 if (sysrq_key != '\0')
318 handle_sysrq(sysrq_key);
319}
320
321static struct xenbus_watch sysrq_watch = {
322 .node = "control/sysrq",
323 .callback = sysrq_handler
324};
325#endif
326
327static struct xenbus_watch shutdown_watch = {
328 .node = "control/shutdown",
329 .callback = shutdown_handler
330};
331
332static struct notifier_block xen_reboot_nb = {
333 .notifier_call = poweroff_nb,
334};
335
336static int setup_shutdown_watcher(void)
337{
338 int err;
339
340 err = register_xenbus_watch(&shutdown_watch);
341 if (err) {
342 pr_err("Failed to set shutdown watcher\n");
343 return err;
344 }
345
346
347#ifdef CONFIG_MAGIC_SYSRQ
348 err = register_xenbus_watch(&sysrq_watch);
349 if (err) {
350 pr_err("Failed to set sysrq watcher\n");
351 return err;
352 }
353#endif
354
355 return 0;
356}
357
358static int shutdown_event(struct notifier_block *notifier,
359 unsigned long event,
360 void *data)
361{
362 setup_shutdown_watcher();
363 return NOTIFY_DONE;
364}
365
366int xen_setup_shutdown_event(void)
367{
368 static struct notifier_block xenstore_notifier = {
369 .notifier_call = shutdown_event
370 };
371
372 if (!xen_domain())
373 return -ENODEV;
374 register_xenstore_notifier(&xenstore_notifier);
375 register_reboot_notifier(&xen_reboot_nb);
376
377 return 0;
378}
379EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
380
381subsys_initcall(xen_setup_shutdown_event);