Merge branch 'xen-upstream' of ssh://master.kernel.org/pub/scm/linux/kernel/git/jeremy/xen

* 'xen-upstream' of ssh://master.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: (44 commits)
  xen: disable all non-virtual drivers
  xen: use iret directly when possible
  xen: suppress abs symbol warnings for unused reloc pointers
  xen: Attempt to patch inline versions of common operations
  xen: Place vcpu_info structure into per-cpu memory
  xen: handle external requests for shutdown, reboot and sysrq
  xen: machine operations
  xen: add virtual network device driver
  xen: add virtual block device driver.
  xen: add the Xenbus sysfs and virtual device hotplug driver
  xen: Add grant table support
  xen: use the hvc console infrastructure for Xen console
  xen: hack to prevent bad segment register reload
  xen: lazy-mmu operations
  xen: Add support for preemption
  xen: SMP guest support
  xen: Implement sched_clock
  xen: Account for stolen time
  xen: ignore RW mapping of RO pages in pagetable_init
  xen: Complete pagetable pinning
  ...

1 files changed, 58 insertions, 0 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 4d141ae3e802..18987c7f6add 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2286,3 +2286,61 @@ asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
 	}
 	return err ? -EFAULT : 0;
 }
+
+char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
+
+static void argv_cleanup(char **argv, char **envp)
+{
+	argv_free(argv);
+}
+
+/**
+ * orderly_poweroff - Trigger an orderly system poweroff
+ * @force: force poweroff if command execution fails
+ *
+ * This may be called from any context to trigger a system shutdown.
+ * If the orderly shutdown fails, it will force an immediate shutdown.
+ */
+int orderly_poweroff(bool force)
+{
+	int argc;
+	char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
+	static char *envp[] = {
+		"HOME=/",
+		"PATH=/sbin:/bin:/usr/sbin:/usr/bin",
+		NULL
+	};
+	int ret = -ENOMEM;
+	struct subprocess_info *info;
+
+	if (argv == NULL) {
+		printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
+		       __func__, poweroff_cmd);
+		goto out;
+	}
+
+	info = call_usermodehelper_setup(argv[0], argv, envp);
+	if (info == NULL) {
+		argv_free(argv);
+		goto out;
+	}
+
+	call_usermodehelper_setcleanup(info, argv_cleanup);
+
+	ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
+
+  out:
+	if (ret && force) {
+		printk(KERN_WARNING "Failed to start orderly shutdown: "
+		       "forcing the issue\n");
+
+		/* I guess this should try to kick off some daemon to
+		   sync and poweroff asap.  Or not even bother syncing
+		   if we're doing an emergency shutdown? */
+		emergency_sync();
+		kernel_power_off();
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(orderly_poweroff);