1 files changed, 40 insertions, 7 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index b95d3c72ba21..071de900c824 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -362,6 +362,29 @@ int unregister_reboot_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_reboot_notifier);
 
+/* Add backwards compatibility for stable trees. */
+#ifndef PF_NO_SETAFFINITY
+#define PF_NO_SETAFFINITY               PF_THREAD_BOUND
+#endif
+
+static void migrate_to_reboot_cpu(void)
+{
+        /* The boot cpu is always logical cpu 0 */
+        int cpu = 0;
+
+        cpu_hotplug_disable();
+
+        /* Make certain the cpu I'm about to reboot on is online */
+        if (!cpu_online(cpu))
+                cpu = cpumask_first(cpu_online_mask);
+
+        /* Prevent races with other tasks migrating this task */
+        current->flags |= PF_NO_SETAFFINITY;
+
+        /* Make certain I only run on the appropriate processor */
+        set_cpus_allowed_ptr(current, cpumask_of(cpu));
+}
+
 /**
  *      kernel_restart - reboot the system
  *      @cmd: pointer to buffer containing command to execute for restart
@@ -373,7 +396,7 @@ EXPORT_SYMBOL(unregister_reboot_notifier);
 void kernel_restart(char *cmd)
 {
         kernel_restart_prepare(cmd);
-        disable_nonboot_cpus();
+        migrate_to_reboot_cpu();
         syscore_shutdown();
         if (!cmd)
                 printk(KERN_EMERG "Restarting system.\n");
@@ -400,7 +423,7 @@ static void kernel_shutdown_prepare(enum system_states state)
 void kernel_halt(void)
 {
         kernel_shutdown_prepare(SYSTEM_HALT);
-        disable_nonboot_cpus();
+        migrate_to_reboot_cpu();
         syscore_shutdown();
         printk(KERN_EMERG "System halted.\n");
         kmsg_dump(KMSG_DUMP_HALT);
@@ -419,7 +442,7 @@ void kernel_power_off(void)
         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
         if (pm_power_off_prepare)
                 pm_power_off_prepare();
-        disable_nonboot_cpus();
+        migrate_to_reboot_cpu();
         syscore_shutdown();
         printk(KERN_EMERG "Power down.\n");
         kmsg_dump(KMSG_DUMP_POWEROFF);
@@ -488,7 +511,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
         case LINUX_REBOOT_CMD_HALT:
                 kernel_halt();
                 do_exit(0);
-                panic("cannot halt");
+                panic("cannot halt.\n");
 
         case LINUX_REBOOT_CMD_POWER_OFF:
                 kernel_power_off();
@@ -1286,6 +1309,17 @@ out:
         return retval;
 }
 
+static void set_special_pids(struct pid *pid)
+{
+        struct task_struct *curr = current->group_leader;
+
+        if (task_session(curr) != pid)
+                change_pid(curr, PIDTYPE_SID, pid);
+
+        if (task_pgrp(curr) != pid)
+                change_pid(curr, PIDTYPE_PGID, pid);
+}
+
 SYSCALL_DEFINE0(setsid)
 {
         struct task_struct *group_leader = current->group_leader;
@@ -1305,7 +1339,7 @@ SYSCALL_DEFINE0(setsid)
                 goto out;
 
         group_leader->signal->leader = 1;
-        __set_special_pids(sid);
+        set_special_pids(sid);
 
         proc_clear_tty(group_leader);
 
@@ -2332,8 +2366,7 @@ static int do_sysinfo(struct sysinfo *info)
 
         memset(info, 0, sizeof(struct sysinfo));
 
-        ktime_get_ts(&tp);
-        monotonic_to_bootbased(&tp);
+        get_monotonic_boottime(&tp);
         info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
 
         get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);