Linux 3.2.80

[pandora-kernel.git] / kernel / sys.c

diff --git a/kernel/sys.c b/kernel/sys.c
index d06c091..9d557df 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -4,7 +4,7 @@
  *  Copyright (C) 1991, 1992  Linus Torvalds
  */
 
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/utsname.h>
 #include <linux/mman.h>
@@ -12,6 +12,7 @@
 #include <linux/prctl.h>
 #include <linux/highuid.h>
 #include <linux/fs.h>
+#include <linux/kmod.h>
 #include <linux/perf_event.h>
 #include <linux/resource.h>
 #include <linux/kernel.h>
@@ -319,7 +320,6 @@ void kernel_restart_prepare(char *cmd)
        system_state = SYSTEM_RESTART;
        usermodehelper_disable();
        device_shutdown();
-       syscore_shutdown();
 }
 
 /**
@@ -353,6 +353,29 @@ 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
@@ -364,6 +387,8 @@ EXPORT_SYMBOL(unregister_reboot_notifier);
 void kernel_restart(char *cmd)
 {
        kernel_restart_prepare(cmd);
+       migrate_to_reboot_cpu();
+       syscore_shutdown();
        if (!cmd)
                printk(KERN_EMERG "Restarting system.\n");
        else
@@ -389,6 +414,7 @@ static void kernel_shutdown_prepare(enum system_states state)
 void kernel_halt(void)
 {
        kernel_shutdown_prepare(SYSTEM_HALT);
+       migrate_to_reboot_cpu();
        syscore_shutdown();
        printk(KERN_EMERG "System halted.\n");
        kmsg_dump(KMSG_DUMP_HALT);
@@ -407,7 +433,7 @@ 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);
@@ -1169,15 +1195,16 @@ DECLARE_RWSEM(uts_sem);
  * Work around broken programs that cannot handle "Linux 3.0".
  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
  */
-static int override_release(char __user *release, int len)
+static int override_release(char __user *release, size_t len)
 {
        int ret = 0;
-       char buf[65];
 
        if (current->personality & UNAME26) {
-               char *rest = UTS_RELEASE;
+               const char *rest = UTS_RELEASE;
+               char buf[65] = { 0 };
                int ndots = 0;
                unsigned v;
+               size_t copy;
 
                while (*rest) {
                        if (*rest == '.' && ++ndots >= 3)
@@ -1187,8 +1214,9 @@ static int override_release(char __user *release, int len)
                        rest++;
                }
                v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
-               snprintf(buf, len, "2.6.%u%s", v, rest);
-               ret = copy_to_user(release, buf, len);
+               copy = clamp_t(size_t, len, 1, sizeof(buf));
+               copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
+               ret = copy_to_user(release, buf, copy + 1);
        }
        return ret;
 }