1 files changed, 142 insertions, 60 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index f006632c2ba7..0bcaed6560ac 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -16,6 +16,8 @@
 #include <linux/init.h>
 #include <linux/highuid.h>
 #include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
 #include <linux/workqueue.h>
 #include <linux/device.h>
 #include <linux/key.h>
@@ -359,6 +361,64 @@ out_unlock:
         return retval;
 }
 
+void emergency_restart(void)
+{
+        machine_emergency_restart();
+}
+EXPORT_SYMBOL_GPL(emergency_restart);
+
+void kernel_restart(char *cmd)
+{
+        notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
+        system_state = SYSTEM_RESTART;
+        device_shutdown();
+        if (!cmd) {
+                printk(KERN_EMERG "Restarting system.\n");
+        } else {
+                printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
+        }
+        printk(".\n");
+        machine_restart(cmd);
+}
+EXPORT_SYMBOL_GPL(kernel_restart);
+
+void kernel_kexec(void)
+{
+#ifdef CONFIG_KEXEC
+        struct kimage *image;
+        image = xchg(&kexec_image, 0);
+        if (!image) {
+                return;
+        }
+        notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
+        system_state = SYSTEM_RESTART;
+        device_shutdown();
+        printk(KERN_EMERG "Starting new kernel\n");
+        machine_shutdown();
+        machine_kexec(image);
+#endif
+}
+EXPORT_SYMBOL_GPL(kernel_kexec);
+
+void kernel_halt(void)
+{
+        notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
+        system_state = SYSTEM_HALT;
+        device_shutdown();
+        printk(KERN_EMERG "System halted.\n");
+        machine_halt();
+}
+EXPORT_SYMBOL_GPL(kernel_halt);
+
+void kernel_power_off(void)
+{
+        notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
+        system_state = SYSTEM_POWER_OFF;
+        device_shutdown();
+        printk(KERN_EMERG "Power down.\n");
+        machine_power_off();
+}
+EXPORT_SYMBOL_GPL(kernel_power_off);
 
 /*
  * Reboot system call: for obvious reasons only root may call it,
@@ -387,11 +447,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
         lock_kernel();
         switch (cmd) {
         case LINUX_REBOOT_CMD_RESTART:
-                notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
-                system_state = SYSTEM_RESTART;
-                device_shutdown();
-                printk(KERN_EMERG "Restarting system.\n");
-                machine_restart(NULL);
+                kernel_restart(NULL);
                 break;
 
         case LINUX_REBOOT_CMD_CAD_ON:
@@ -403,21 +459,13 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
                 break;
 
         case LINUX_REBOOT_CMD_HALT:
-                notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
-                system_state = SYSTEM_HALT;
-                device_shutdown();
-                printk(KERN_EMERG "System halted.\n");
-                machine_halt();
+                kernel_halt();
                 unlock_kernel();
                 do_exit(0);
                 break;
 
         case LINUX_REBOOT_CMD_POWER_OFF:
-                notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
-                system_state = SYSTEM_POWER_OFF;
-                device_shutdown();
-                printk(KERN_EMERG "Power down.\n");
-                machine_power_off();
+                kernel_power_off();
                 unlock_kernel();
                 do_exit(0);
                 break;
@@ -429,13 +477,14 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
                 }
                 buffer[sizeof(buffer) - 1] = '\0';
 
-                notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
-                system_state = SYSTEM_RESTART;
-                device_shutdown();
-                printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
-                machine_restart(buffer);
+                kernel_restart(buffer);
                 break;
 
+        case LINUX_REBOOT_CMD_KEXEC:
+                kernel_kexec();
+                unlock_kernel();
+                return -EINVAL;
+
 #ifdef CONFIG_SOFTWARE_SUSPEND
         case LINUX_REBOOT_CMD_SW_SUSPEND:
                 {
@@ -455,8 +504,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
 
 static void deferred_cad(void *dummy)
 {
-        notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
-        machine_restart(NULL);
+        kernel_restart(NULL);
 }
 
 /*
@@ -525,7 +573,7 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
         }
         if (new_egid != old_egid)
         {
-                current->mm->dumpable = 0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         if (rgid != (gid_t) -1 ||
@@ -556,7 +604,7 @@ asmlinkage long sys_setgid(gid_t gid)
         {
                 if(old_egid != gid)
                 {
-                        current->mm->dumpable=0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->gid = current->egid = current->sgid = current->fsgid = gid;
@@ -565,7 +613,7 @@ asmlinkage long sys_setgid(gid_t gid)
         {
                 if(old_egid != gid)
                 {
-                        current->mm->dumpable=0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->egid = current->fsgid = gid;
@@ -596,7 +644,7 @@ static int set_user(uid_t new_ruid, int dumpclear)
 
         if(dumpclear)
         {
-                current->mm->dumpable = 0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         current->uid = new_ruid;
@@ -653,7 +701,7 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 
         if (new_euid != old_euid)
         {
-                current->mm->dumpable=0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         current->fsuid = current->euid = new_euid;
@@ -703,7 +751,7 @@ asmlinkage long sys_setuid(uid_t uid)
 
         if (old_euid != uid)
         {
-                current->mm->dumpable = 0;
+                current->mm->dumpable = suid_dumpable;
                 smp_wmb();
         }
         current->fsuid = current->euid = uid;
@@ -748,7 +796,7 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
         if (euid != (uid_t) -1) {
                 if (euid != current->euid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->euid = euid;
@@ -798,7 +846,7 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
         if (egid != (gid_t) -1) {
                 if (egid != current->egid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->egid = egid;
@@ -845,7 +893,7 @@ asmlinkage long sys_setfsuid(uid_t uid)
         {
                 if (uid != old_fsuid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->fsuid = uid;
@@ -875,7 +923,7 @@ asmlinkage long sys_setfsgid(gid_t gid)
         {
                 if (gid != old_fsgid)
                 {
-                        current->mm->dumpable = 0;
+                        current->mm->dumpable = suid_dumpable;
                         smp_wmb();
                 }
                 current->fsgid = gid;
@@ -894,35 +942,69 @@ asmlinkage long sys_times(struct tms __user * tbuf)
          */
         if (tbuf) {
                 struct tms tmp;
-                struct task_struct *tsk = current;
-                struct task_struct *t;
                 cputime_t utime, stime, cutime, cstime;
 
-                read_lock(&tasklist_lock);
-                utime = tsk->signal->utime;
-                stime = tsk->signal->stime;
-                t = tsk;
-                do {
-                        utime = cputime_add(utime, t->utime);
-                        stime = cputime_add(stime, t->stime);
-                        t = next_thread(t);
-                } while (t != tsk);
-
-                /*
-                 * While we have tasklist_lock read-locked, no dying thread
-                 * can be updating current->signal->[us]time.  Instead,
-                 * we got their counts included in the live thread loop.
-                 * However, another thread can come in right now and
-                 * do a wait call that updates current->signal->c[us]time.
-                 * To make sure we always see that pair updated atomically,
-                 * we take the siglock around fetching them.
-                 */
-                spin_lock_irq(&tsk->sighand->siglock);
-                cutime = tsk->signal->cutime;
-                cstime = tsk->signal->cstime;
-                spin_unlock_irq(&tsk->sighand->siglock);
-                read_unlock(&tasklist_lock);
+#ifdef CONFIG_SMP
+                if (thread_group_empty(current)) {
+                        /*
+                         * Single thread case without the use of any locks.
+                         *
+                         * We may race with release_task if two threads are
+                         * executing. However, release task first adds up the
+                         * counters (__exit_signal) before  removing the task
+                         * from the process tasklist (__unhash_process).
+                         * __exit_signal also acquires and releases the
+                         * siglock which results in the proper memory ordering
+                         * so that the list modifications are always visible
+                         * after the counters have been updated.
+                         *
+                         * If the counters have been updated by the second thread
+                         * but the thread has not yet been removed from the list
+                         * then the other branch will be executing which will
+                         * block on tasklist_lock until the exit handling of the
+                         * other task is finished.
+                         *
+                         * This also implies that the sighand->siglock cannot
+                         * be held by another processor. So we can also
+                         * skip acquiring that lock.
+                         */
+                        utime = cputime_add(current->signal->utime, current->utime);
+                        stime = cputime_add(current->signal->utime, current->stime);
+                        cutime = current->signal->cutime;
+                        cstime = current->signal->cstime;
+                } else
+#endif
+                {
+
+                        /* Process with multiple threads */
+                        struct task_struct *tsk = current;
+                        struct task_struct *t;
 
+                        read_lock(&tasklist_lock);
+                        utime = tsk->signal->utime;
+                        stime = tsk->signal->stime;
+                        t = tsk;
+                        do {
+                                utime = cputime_add(utime, t->utime);
+                                stime = cputime_add(stime, t->stime);
+                                t = next_thread(t);
+                        } while (t != tsk);
+
+                        /*
+                         * While we have tasklist_lock read-locked, no dying thread
+                         * can be updating current->signal->[us]time.  Instead,
+                         * we got their counts included in the live thread loop.
+                         * However, another thread can come in right now and
+                         * do a wait call that updates current->signal->c[us]time.
+                         * To make sure we always see that pair updated atomically,
+                         * we take the siglock around fetching them.
+                         */
+                        spin_lock_irq(&tsk->sighand->siglock);
+                        cutime = tsk->signal->cutime;
+                        cstime = tsk->signal->cstime;
+                        spin_unlock_irq(&tsk->sighand->siglock);
+                        read_unlock(&tasklist_lock);
+                }
                 tmp.tms_utime = cputime_to_clock_t(utime);
                 tmp.tms_stime = cputime_to_clock_t(stime);
                 tmp.tms_cutime = cputime_to_clock_t(cutime);
@@ -1225,7 +1307,7 @@ static void groups_sort(struct group_info *group_info)
 }
 
 /* a simple bsearch */
-static int groups_search(struct group_info *group_info, gid_t grp)
+int groups_search(struct group_info *group_info, gid_t grp)
 {
         int left, right;
 
@@ -1652,7 +1734,7 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                                 error = 1;
                         break;
                 case PR_SET_DUMPABLE:
-                        if (arg2 != 0 && arg2 != 1) {
+                        if (arg2 < 0 || arg2 > 2) {
                                 error = -EINVAL;
                                 break;
                         }