| 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 | #include <linux/export.h> |
| 13 | |
| 14 | #include <xen/xen.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> |
| 20 | |
| 21 | #include <asm/xen/hypercall.h> |
| 22 | #include <asm/xen/page.h> |
| 23 | #include <asm/xen/hypervisor.h> |
| 24 | |
| 25 | enum shutdown_state { |
| 26 | SHUTDOWN_INVALID = -1, |
| 27 | SHUTDOWN_POWEROFF = 0, |
| 28 | SHUTDOWN_SUSPEND = 2, |
| 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. */ |
| 33 | SHUTDOWN_HALT = 4, |
| 34 | }; |
| 35 | |
| 36 | /* Ignore multiple shutdown requests. */ |
| 37 | static enum shutdown_state shutting_down = SHUTDOWN_INVALID; |
| 38 | |
| 39 | struct suspend_info { |
| 40 | int cancelled; |
| 41 | unsigned long arg; /* extra hypercall argument */ |
| 42 | void (*pre)(void); |
| 43 | void (*post)(int cancelled); |
| 44 | }; |
| 45 | |
| 46 | static void xen_hvm_post_suspend(int cancelled) |
| 47 | { |
| 48 | xen_arch_hvm_post_suspend(cancelled); |
| 49 | gnttab_resume(); |
| 50 | } |
| 51 | |
| 52 | static void xen_pre_suspend(void) |
| 53 | { |
| 54 | xen_mm_pin_all(); |
| 55 | gnttab_suspend(); |
| 56 | xen_arch_pre_suspend(); |
| 57 | } |
| 58 | |
| 59 | static void xen_post_suspend(int cancelled) |
| 60 | { |
| 61 | xen_arch_post_suspend(cancelled); |
| 62 | gnttab_resume(); |
| 63 | xen_mm_unpin_all(); |
| 64 | } |
| 65 | |
| 66 | #ifdef CONFIG_HIBERNATE_CALLBACKS |
| 67 | static int xen_suspend(void *data) |
| 68 | { |
| 69 | struct suspend_info *si = data; |
| 70 | int err; |
| 71 | |
| 72 | BUG_ON(!irqs_disabled()); |
| 73 | |
| 74 | err = syscore_suspend(); |
| 75 | if (err) { |
| 76 | printk(KERN_ERR "xen_suspend: system core suspend failed: %d\n", |
| 77 | err); |
| 78 | return err; |
| 79 | } |
| 80 | |
| 81 | if (si->pre) |
| 82 | si->pre(); |
| 83 | |
| 84 | /* |
| 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. |
| 88 | */ |
| 89 | si->cancelled = HYPERVISOR_suspend(si->arg); |
| 90 | |
| 91 | if (si->post) |
| 92 | si->post(si->cancelled); |
| 93 | |
| 94 | if (!si->cancelled) { |
| 95 | xen_irq_resume(); |
| 96 | xen_console_resume(); |
| 97 | xen_timer_resume(); |
| 98 | } |
| 99 | |
| 100 | syscore_resume(); |
| 101 | |
| 102 | return 0; |
| 103 | } |
| 104 | |
| 105 | static void do_suspend(void) |
| 106 | { |
| 107 | int err; |
| 108 | struct suspend_info si; |
| 109 | |
| 110 | shutting_down = SHUTDOWN_SUSPEND; |
| 111 | |
| 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 |
| 115 | during suspend. */ |
| 116 | err = freeze_processes(); |
| 117 | if (err) { |
| 118 | printk(KERN_ERR "xen suspend: freeze failed %d\n", err); |
| 119 | goto out; |
| 120 | } |
| 121 | #endif |
| 122 | |
| 123 | err = dpm_suspend_start(PMSG_FREEZE); |
| 124 | if (err) { |
| 125 | printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err); |
| 126 | goto out_thaw; |
| 127 | } |
| 128 | |
| 129 | printk(KERN_DEBUG "suspending xenstore...\n"); |
| 130 | xs_suspend(); |
| 131 | |
| 132 | err = dpm_suspend_end(PMSG_FREEZE); |
| 133 | if (err) { |
| 134 | printk(KERN_ERR "dpm_suspend_end failed: %d\n", err); |
| 135 | si.cancelled = 0; |
| 136 | goto out_resume; |
| 137 | } |
| 138 | |
| 139 | si.cancelled = 1; |
| 140 | |
| 141 | if (xen_hvm_domain()) { |
| 142 | si.arg = 0UL; |
| 143 | si.pre = NULL; |
| 144 | si.post = &xen_hvm_post_suspend; |
| 145 | } else { |
| 146 | si.arg = virt_to_mfn(xen_start_info); |
| 147 | si.pre = &xen_pre_suspend; |
| 148 | si.post = &xen_post_suspend; |
| 149 | } |
| 150 | |
| 151 | err = stop_machine(xen_suspend, &si, cpumask_of(0)); |
| 152 | |
| 153 | dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE); |
| 154 | |
| 155 | if (err) { |
| 156 | printk(KERN_ERR "failed to start xen_suspend: %d\n", err); |
| 157 | si.cancelled = 1; |
| 158 | } |
| 159 | |
| 160 | out_resume: |
| 161 | if (!si.cancelled) { |
| 162 | xen_arch_resume(); |
| 163 | xs_resume(); |
| 164 | } else |
| 165 | xs_suspend_cancel(); |
| 166 | |
| 167 | dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE); |
| 168 | |
| 169 | /* Make sure timer events get retriggered on all CPUs */ |
| 170 | clock_was_set(); |
| 171 | |
| 172 | out_thaw: |
| 173 | #ifdef CONFIG_PREEMPT |
| 174 | thaw_processes(); |
| 175 | out: |
| 176 | #endif |
| 177 | shutting_down = SHUTDOWN_INVALID; |
| 178 | } |
| 179 | #endif /* CONFIG_HIBERNATE_CALLBACKS */ |
| 180 | |
| 181 | struct shutdown_handler { |
| 182 | const char *command; |
| 183 | void (*cb)(void); |
| 184 | }; |
| 185 | |
| 186 | static void do_poweroff(void) |
| 187 | { |
| 188 | shutting_down = SHUTDOWN_POWEROFF; |
| 189 | orderly_poweroff(false); |
| 190 | } |
| 191 | |
| 192 | static void do_reboot(void) |
| 193 | { |
| 194 | shutting_down = SHUTDOWN_POWEROFF; /* ? */ |
| 195 | ctrl_alt_del(); |
| 196 | } |
| 197 | |
| 198 | static void shutdown_handler(struct xenbus_watch *watch, |
| 199 | const char **vec, unsigned int len) |
| 200 | { |
| 201 | char *str; |
| 202 | struct xenbus_transaction xbt; |
| 203 | int err; |
| 204 | static struct shutdown_handler handlers[] = { |
| 205 | { "poweroff", do_poweroff }, |
| 206 | { "halt", do_poweroff }, |
| 207 | { "reboot", do_reboot }, |
| 208 | #ifdef CONFIG_HIBERNATE_CALLBACKS |
| 209 | { "suspend", do_suspend }, |
| 210 | #endif |
| 211 | {NULL, NULL}, |
| 212 | }; |
| 213 | static struct shutdown_handler *handler; |
| 214 | |
| 215 | if (shutting_down != SHUTDOWN_INVALID) |
| 216 | return; |
| 217 | |
| 218 | again: |
| 219 | err = xenbus_transaction_start(&xbt); |
| 220 | if (err) |
| 221 | return; |
| 222 | |
| 223 | str = (char *)xenbus_read(xbt, "control", "shutdown", NULL); |
| 224 | /* Ignore read errors and empty reads. */ |
| 225 | if (XENBUS_IS_ERR_READ(str)) { |
| 226 | xenbus_transaction_end(xbt, 1); |
| 227 | return; |
| 228 | } |
| 229 | |
| 230 | for (handler = &handlers[0]; handler->command; handler++) { |
| 231 | if (strcmp(str, handler->command) == 0) |
| 232 | break; |
| 233 | } |
| 234 | |
| 235 | /* Only acknowledge commands which we are prepared to handle. */ |
| 236 | if (handler->cb) |
| 237 | xenbus_write(xbt, "control", "shutdown", ""); |
| 238 | |
| 239 | err = xenbus_transaction_end(xbt, 0); |
| 240 | if (err == -EAGAIN) { |
| 241 | kfree(str); |
| 242 | goto again; |
| 243 | } |
| 244 | |
| 245 | if (handler->cb) { |
| 246 | handler->cb(); |
| 247 | } else { |
| 248 | printk(KERN_INFO "Ignoring shutdown request: %s\n", str); |
| 249 | shutting_down = SHUTDOWN_INVALID; |
| 250 | } |
| 251 | |
| 252 | kfree(str); |
| 253 | } |
| 254 | |
| 255 | #ifdef CONFIG_MAGIC_SYSRQ |
| 256 | static void sysrq_handler(struct xenbus_watch *watch, const char **vec, |
| 257 | unsigned int len) |
| 258 | { |
| 259 | char sysrq_key = '\0'; |
| 260 | struct xenbus_transaction xbt; |
| 261 | int err; |
| 262 | |
| 263 | again: |
| 264 | err = xenbus_transaction_start(&xbt); |
| 265 | if (err) |
| 266 | return; |
| 267 | if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) { |
| 268 | printk(KERN_ERR "Unable to read sysrq code in " |
| 269 | "control/sysrq\n"); |
| 270 | xenbus_transaction_end(xbt, 1); |
| 271 | return; |
| 272 | } |
| 273 | |
| 274 | if (sysrq_key != '\0') |
| 275 | xenbus_printf(xbt, "control", "sysrq", "%c", '\0'); |
| 276 | |
| 277 | err = xenbus_transaction_end(xbt, 0); |
| 278 | if (err == -EAGAIN) |
| 279 | goto again; |
| 280 | |
| 281 | if (sysrq_key != '\0') |
| 282 | handle_sysrq(sysrq_key); |
| 283 | } |
| 284 | |
| 285 | static struct xenbus_watch sysrq_watch = { |
| 286 | .node = "control/sysrq", |
| 287 | .callback = sysrq_handler |
| 288 | }; |
| 289 | #endif |
| 290 | |
| 291 | static struct xenbus_watch shutdown_watch = { |
| 292 | .node = "control/shutdown", |
| 293 | .callback = shutdown_handler |
| 294 | }; |
| 295 | |
| 296 | static int setup_shutdown_watcher(void) |
| 297 | { |
| 298 | int err; |
| 299 | |
| 300 | err = register_xenbus_watch(&shutdown_watch); |
| 301 | if (err) { |
| 302 | printk(KERN_ERR "Failed to set shutdown watcher\n"); |
| 303 | return err; |
| 304 | } |
| 305 | |
| 306 | #ifdef CONFIG_MAGIC_SYSRQ |
| 307 | err = register_xenbus_watch(&sysrq_watch); |
| 308 | if (err) { |
| 309 | printk(KERN_ERR "Failed to set sysrq watcher\n"); |
| 310 | return err; |
| 311 | } |
| 312 | #endif |
| 313 | |
| 314 | return 0; |
| 315 | } |
| 316 | |
| 317 | static int shutdown_event(struct notifier_block *notifier, |
| 318 | unsigned long event, |
| 319 | void *data) |
| 320 | { |
| 321 | setup_shutdown_watcher(); |
| 322 | return NOTIFY_DONE; |
| 323 | } |
| 324 | |
| 325 | int xen_setup_shutdown_event(void) |
| 326 | { |
| 327 | static struct notifier_block xenstore_notifier = { |
| 328 | .notifier_call = shutdown_event |
| 329 | }; |
| 330 | |
| 331 | if (!xen_domain()) |
| 332 | return -ENODEV; |
| 333 | register_xenstore_notifier(&xenstore_notifier); |
| 334 | |
| 335 | return 0; |
| 336 | } |
| 337 | EXPORT_SYMBOL_GPL(xen_setup_shutdown_event); |
| 338 | |
| 339 | subsys_initcall(xen_setup_shutdown_event); |