1 files changed, 337 insertions, 0 deletions
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
new file mode 100644
index 00000000..0b5366b5
--- /dev/null
+++ b/drivers/xen/manage.c
@@ -0,0 +1,337 @@
+/*
+ * Handle extern requests for shutdown, reboot and sysrq
+ */
+#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 <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;
+	unsigned long arg; /* extra hypercall argument */
+	void (*pre)(void);
+	void (*post)(int cancelled);
+};
+
+static void xen_hvm_post_suspend(int cancelled)
+{
+	xen_arch_hvm_post_suspend(cancelled);
+	gnttab_resume();
+}
+
+static void xen_pre_suspend(void)
+{
+	xen_mm_pin_all();
+	gnttab_suspend();
+	xen_arch_pre_suspend();
+}
+
+static void xen_post_suspend(int cancelled)
+{
+	xen_arch_post_suspend(cancelled);
+	gnttab_resume();
+	xen_mm_unpin_all();
+}
+
+#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) {
+		printk(KERN_ERR "xen_suspend: system core suspend failed: %d\n",
+			err);
+		return err;
+	}
+
+	if (si->pre)
+		si->pre();
+
+	/*
+	 * 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(si->arg);
+
+	if (si->post)
+		si->post(si->cancelled);
+
+	if (!si->cancelled) {
+		xen_irq_resume();
+		xen_console_resume();
+		xen_timer_resume();
+	}
+
+	syscore_resume();
+
+	return 0;
+}
+
+static void do_suspend(void)
+{
+	int err;
+	struct suspend_info si;
+
+	shutting_down = SHUTDOWN_SUSPEND;
+
+#ifdef CONFIG_PREEMPT
+	/* If the kernel is preemptible, we need to freeze all the processes
+	   to prevent them from being in the middle of a pagetable update
+	   during suspend. */
+	err = freeze_processes();
+	if (err) {
+		printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
+		goto out;
+	}
+#endif
+
+	err = dpm_suspend_start(PMSG_FREEZE);
+	if (err) {
+		printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
+		goto out_thaw;
+	}
+
+	printk(KERN_DEBUG "suspending xenstore...\n");
+	xs_suspend();
+
+	err = dpm_suspend_noirq(PMSG_FREEZE);
+	if (err) {
+		printk(KERN_ERR "dpm_suspend_noirq failed: %d\n", err);
+		goto out_resume;
+	}
+
+	si.cancelled = 1;
+
+	if (xen_hvm_domain()) {
+		si.arg = 0UL;
+		si.pre = NULL;
+		si.post = &xen_hvm_post_suspend;
+	} else {
+		si.arg = virt_to_mfn(xen_start_info);
+		si.pre = &xen_pre_suspend;
+		si.post = &xen_post_suspend;
+	}
+
+	err = stop_machine(xen_suspend, &si, cpumask_of(0));
+
+	dpm_resume_noirq(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
+
+	if (err) {
+		printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
+		si.cancelled = 1;
+	}
+
+out_resume:
+	if (!si.cancelled) {
+		xen_arch_resume();
+		xs_resume();
+	} else
+		xs_suspend_cancel();
+
+	dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
+
+	/* Make sure timer events get retriggered on all CPUs */
+	clock_was_set();
+
+out_thaw:
+#ifdef CONFIG_PREEMPT
+	thaw_processes();
+out:
+#endif
+	shutting_down = SHUTDOWN_INVALID;
+}
+#endif	/* CONFIG_HIBERNATE_CALLBACKS */
+
+struct shutdown_handler {
+	const char *command;
+	void (*cb)(void);
+};
+
+static void do_poweroff(void)
+{
+	shutting_down = SHUTDOWN_POWEROFF;
+	orderly_poweroff(false);
+}
+
+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 {
+		printk(KERN_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)) {
+		printk(KERN_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 int setup_shutdown_watcher(void)
+{
+	int err;
+
+	err = register_xenbus_watch(&shutdown_watch);
+	if (err) {
+		printk(KERN_ERR "Failed to set shutdown watcher\n");
+		return err;
+	}
+
+#ifdef CONFIG_MAGIC_SYSRQ
+	err = register_xenbus_watch(&sysrq_watch);
+	if (err) {
+		printk(KERN_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);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
+
+subsys_initcall(xen_setup_shutdown_event);