--- /dev/null
+/*
+ * Handle extern requests for shutdown, reboot and sysrq
+ */
+
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/reboot.h>
+#include <linux/sysrq.h>
+#include <linux/stop_machine.h>
+#include <linux/freezer.h>
+#include <linux/syscore_ops.h>
+#include <linux/export.h>
+
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/grant_table.h>
+#include <xen/events.h>
+#include <xen/hvc-console.h>
+#include <xen/xen-ops.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/page.h>
+#include <asm/xen/hypervisor.h>
+
+enum shutdown_state {
+ SHUTDOWN_INVALID = -1,
+ SHUTDOWN_POWEROFF = 0,
+ SHUTDOWN_SUSPEND = 2,
+ /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
+ report a crash, not be instructed to crash!
+ HALT is the same as POWEROFF, as far as we're concerned. The tools use
+ the distinction when we return the reason code to them. */
+ SHUTDOWN_HALT = 4,
+};
+
+/* Ignore multiple shutdown requests. */
+static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
+
+struct suspend_info {
+ int cancelled;
+};
+
+static RAW_NOTIFIER_HEAD(xen_resume_notifier);
+
+void xen_resume_notifier_register(struct notifier_block *nb)
+{
+ raw_notifier_chain_register(&xen_resume_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
+
+void xen_resume_notifier_unregister(struct notifier_block *nb)
+{
+ raw_notifier_chain_unregister(&xen_resume_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
+
+#ifdef CONFIG_HIBERNATE_CALLBACKS
+static int xen_suspend(void *data)
+{
+ struct suspend_info *si = data;
+ int err;
+
+ BUG_ON(!irqs_disabled());
+
+ err = syscore_suspend();
+ if (err) {
+ pr_err("%s: system core suspend failed: %d\n", __func__, err);
+ return err;
+ }
+
+ gnttab_suspend();
+ xen_arch_pre_suspend();
+
+ /*
+ * This hypercall returns 1 if suspend was cancelled
+ * or the domain was merely checkpointed, and 0 if it
+ * is resuming in a new domain.
+ */
+ si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
+ ? virt_to_mfn(xen_start_info)
+ : 0);
+
+ xen_arch_post_suspend(si->cancelled);
+ gnttab_resume();
+
+ if (!si->cancelled) {
+ xen_irq_resume();
+ xen_timer_resume();
+ }
+
+ syscore_resume();
+
+ return 0;
+}
+
+static void do_suspend(void)
+{
+ int err;
+ struct suspend_info si;
+
+ shutting_down = SHUTDOWN_SUSPEND;
+
+ err = freeze_processes();
+ if (err) {
+ pr_err("%s: freeze processes failed %d\n", __func__, err);
+ goto out;
+ }
+
+ err = freeze_kernel_threads();
+ if (err) {
+ pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
+ goto out_thaw;
+ }
+
+ err = dpm_suspend_start(PMSG_FREEZE);
+ if (err) {
+ pr_err("%s: dpm_suspend_start %d\n", __func__, err);
+ goto out_thaw;
+ }
+
+ printk(KERN_DEBUG "suspending xenstore...\n");
+ xs_suspend();
+
+ err = dpm_suspend_end(PMSG_FREEZE);
+ if (err) {
+ pr_err("dpm_suspend_end failed: %d\n", err);
+ si.cancelled = 0;
+ goto out_resume;
+ }
+
+ xen_arch_suspend();
+
+ si.cancelled = 1;
+
+ err = stop_machine(xen_suspend, &si, cpumask_of(0));
+
+ /* Resume console as early as possible. */
+ if (!si.cancelled)
+ xen_console_resume();
+
+ raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
+
+ dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
+
+ if (err) {
+ pr_err("failed to start xen_suspend: %d\n", err);
+ si.cancelled = 1;
+ }
+
+ xen_arch_resume();
+
+out_resume:
+ if (!si.cancelled)
+ xs_resume();
+ else
+ xs_suspend_cancel();
+
+ dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
+
+out_thaw:
+ thaw_processes();
+out:
+ shutting_down = SHUTDOWN_INVALID;
+}
+#endif /* CONFIG_HIBERNATE_CALLBACKS */
+
+struct shutdown_handler {
+ const char *command;
+ void (*cb)(void);
+};
+
+static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
+{
+ switch (code) {
+ case SYS_DOWN:
+ case SYS_HALT:
+ case SYS_POWER_OFF:
+ shutting_down = SHUTDOWN_POWEROFF;
+ default:
+ break;
+ }
+ return NOTIFY_DONE;
+}
+static void do_poweroff(void)
+{
+ switch (system_state) {
+ case SYSTEM_BOOTING:
+ orderly_poweroff(true);
+ break;
+ case SYSTEM_RUNNING:
+ orderly_poweroff(false);
+ break;
+ default:
+ /* Don't do it when we are halting/rebooting. */
+ pr_info("Ignoring Xen toolstack shutdown.\n");
+ break;
+ }
+}
+
+static void do_reboot(void)
+{
+ shutting_down = SHUTDOWN_POWEROFF; /* ? */
+ ctrl_alt_del();
+}
+
+static void shutdown_handler(struct xenbus_watch *watch,
+ const char **vec, unsigned int len)
+{
+ char *str;
+ struct xenbus_transaction xbt;
+ int err;
+ static struct shutdown_handler handlers[] = {
+ { "poweroff", do_poweroff },
+ { "halt", do_poweroff },
+ { "reboot", do_reboot },
+#ifdef CONFIG_HIBERNATE_CALLBACKS
+ { "suspend", do_suspend },
+#endif
+ {NULL, NULL},
+ };
+ static struct shutdown_handler *handler;
+
+ if (shutting_down != SHUTDOWN_INVALID)
+ return;
+
+ again:
+ err = xenbus_transaction_start(&xbt);
+ if (err)
+ return;
+
+ str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
+ /* Ignore read errors and empty reads. */
+ if (XENBUS_IS_ERR_READ(str)) {
+ xenbus_transaction_end(xbt, 1);
+ return;
+ }
+
+ for (handler = &handlers[0]; handler->command; handler++) {
+ if (strcmp(str, handler->command) == 0)
+ break;
+ }
+
+ /* Only acknowledge commands which we are prepared to handle. */
+ if (handler->cb)
+ xenbus_write(xbt, "control", "shutdown", "");
+
+ err = xenbus_transaction_end(xbt, 0);
+ if (err == -EAGAIN) {
+ kfree(str);
+ goto again;
+ }
+
+ if (handler->cb) {
+ handler->cb();
+ } else {
+ pr_info("Ignoring shutdown request: %s\n", str);
+ shutting_down = SHUTDOWN_INVALID;
+ }
+
+ kfree(str);
+}
+
+#ifdef CONFIG_MAGIC_SYSRQ
+static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
+ unsigned int len)
+{
+ char sysrq_key = '\0';
+ struct xenbus_transaction xbt;
+ int err;
+
+ again:
+ err = xenbus_transaction_start(&xbt);
+ if (err)
+ return;
+ if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
+ pr_err("Unable to read sysrq code in control/sysrq\n");
+ xenbus_transaction_end(xbt, 1);
+ return;
+ }
+
+ if (sysrq_key != '\0')
+ xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
+
+ err = xenbus_transaction_end(xbt, 0);
+ if (err == -EAGAIN)
+ goto again;
+
+ if (sysrq_key != '\0')
+ handle_sysrq(sysrq_key);
+}
+
+static struct xenbus_watch sysrq_watch = {
+ .node = "control/sysrq",
+ .callback = sysrq_handler
+};
+#endif
+
+static struct xenbus_watch shutdown_watch = {
+ .node = "control/shutdown",
+ .callback = shutdown_handler
+};
+
+static struct notifier_block xen_reboot_nb = {
+ .notifier_call = poweroff_nb,
+};
+
+static int setup_shutdown_watcher(void)
+{
+ int err;
+
+ err = register_xenbus_watch(&shutdown_watch);
+ if (err) {
+ pr_err("Failed to set shutdown watcher\n");
+ return err;
+ }
+
+
+#ifdef CONFIG_MAGIC_SYSRQ
+ err = register_xenbus_watch(&sysrq_watch);
+ if (err) {
+ pr_err("Failed to set sysrq watcher\n");
+ return err;
+ }
+#endif
+
+ return 0;
+}
+
+static int shutdown_event(struct notifier_block *notifier,
+ unsigned long event,
+ void *data)
+{
+ setup_shutdown_watcher();
+ return NOTIFY_DONE;
+}
+
+int xen_setup_shutdown_event(void)
+{
+ static struct notifier_block xenstore_notifier = {
+ .notifier_call = shutdown_event
+ };
+
+ if (!xen_domain())
+ return -ENODEV;
+ register_xenstore_notifier(&xenstore_notifier);
+ register_reboot_notifier(&xen_reboot_nb);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
+
+subsys_initcall(xen_setup_shutdown_event);
Code Review / kvmfornfv.git / blobdiff