Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fixes from Thomas Gleixner:
 "The itimer removal one is not strictly a fix, but I really wanted to
  avoid a rebase of the urgent ones."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "clocksource: Load the ACPI PM clocksource asynchronously"
  clockevents: tTack broadcast device mode change in tick_broadcast_switch_to_oneshot()
  itimer: Use printk_once instead of WARN_ONCE
  nohz: Fix stale jiffies update in tick_nohz_restart()
  tick: Document TICK_ONESHOT config option
  proc: stats: Use arch_idle_time for idle and iowait times if available
  itimer: Schedule silent NULL pointer fixup in setitimer() for removal

Documentation/feature-removal-schedule.txt

@@ -531,3 +531,11 @@ Why:	There appear to be no production users of the get_robust_list syscall,
 	of ASLR. It was only ever intended for debugging, so it should be
 	removed.
 Who:	Kees Cook <keescook@chromium.org>
+
+----------------------------
+
+What:	setitimer accepts user NULL pointer (value)
+When:	3.6
+Why:	setitimer is not returning -EFAULT if user pointer is NULL. This
+	violates the spec.
+Who:	Sasikantha Babu <sasikanth.v19@gmail.com>

drivers/clocksource/acpi_pm.c

@@ -23,7 +23,6 @@
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/delay.h>
-#include <linux/async.h>
 #include <asm/io.h>
 
 /*
@@ -180,15 +179,17 @@ static int verify_pmtmr_rate(void)
 /* Number of reads we try to get two different values */
 #define ACPI_PM_READ_CHECKS 10000
 
-static void __init acpi_pm_clocksource_async(void *unused, async_cookie_t cookie)
+static int __init init_acpi_pm_clocksource(void)
 {
 	cycle_t value1, value2;
 	unsigned int i, j = 0;
 
+	if (!pmtmr_ioport)
+		return -ENODEV;
 
 	/* "verify" this timing source: */
 	for (j = 0; j < ACPI_PM_MONOTONICITY_CHECKS; j++) {
-		usleep_range(100 * j, 100 * j + 100);
+		udelay(100 * j);
 		value1 = clocksource_acpi_pm.read(&clocksource_acpi_pm);
 		for (i = 0; i < ACPI_PM_READ_CHECKS; i++) {
 			value2 = clocksource_acpi_pm.read(&clocksource_acpi_pm);
@@ -202,34 +203,25 @@ static void __init acpi_pm_clocksource_async(void *unused, async_cookie_t cookie
 			       " 0x%#llx, 0x%#llx - aborting.\n",
 			       value1, value2);
 			pmtmr_ioport = 0;
-			return;
+			return -EINVAL;
 		}
 		if (i == ACPI_PM_READ_CHECKS) {
 			printk(KERN_INFO "PM-Timer failed consistency check "
 			       " (0x%#llx) - aborting.\n", value1);
 			pmtmr_ioport = 0;
-			return;
+			return -ENODEV;
 		}
 	}
 
 	if (verify_pmtmr_rate() != 0){
 		pmtmr_ioport = 0;
-		return;
+		return -ENODEV;
 	}
 
-	clocksource_register_hz(&clocksource_acpi_pm,
+	return clocksource_register_hz(&clocksource_acpi_pm,
 						PMTMR_TICKS_PER_SEC);
 }
 
-static int __init init_acpi_pm_clocksource(void)
-{
-	if (!pmtmr_ioport)
-		return -ENODEV;
-
-	async_schedule(acpi_pm_clocksource_async, NULL);
-	return 0;
-}
-
 /* We use fs_initcall because we want the PCI fixups to have run
  * but we still need to load before device_initcall
  */

fs/proc/stat.c

@@ -18,19 +18,39 @@
 #ifndef arch_irq_stat
 #define arch_irq_stat() 0
 #endif
-#ifndef arch_idle_time
-#define arch_idle_time(cpu) 0
-#endif
+
+#ifdef arch_idle_time
+
+static cputime64_t get_idle_time(int cpu)
+{
+	cputime64_t idle;
+
+	idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
+	if (cpu_online(cpu) && !nr_iowait_cpu(cpu))
+		idle += arch_idle_time(cpu);
+	return idle;
+}
+
+static cputime64_t get_iowait_time(int cpu)
+{
+	cputime64_t iowait;
+
+	iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];
+	if (cpu_online(cpu) && nr_iowait_cpu(cpu))
+		iowait += arch_idle_time(cpu);
+	return iowait;
+}
+
+#else
 
 static u64 get_idle_time(int cpu)
 {
 	u64 idle, idle_time = get_cpu_idle_time_us(cpu, NULL);
 
-	if (idle_time == -1ULL) {
+	if (idle_time == -1ULL)
 		/* !NO_HZ so we can rely on cpustat.idle */
 		idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
-		idle += arch_idle_time(cpu);
-	} else
+	else
 		idle = usecs_to_cputime64(idle_time);
 
 	return idle;
@@ -49,6 +69,8 @@ static u64 get_iowait_time(int cpu)
 	return iowait;
 }
 
+#endif
+
 static int show_stat(struct seq_file *p, void *v)
 {
 	int i, j;

kernel/itimer.c

@@ -284,8 +284,12 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
 	if (value) {
 		if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
 			return -EFAULT;
-	} else
-		memset((char *) &set_buffer, 0, sizeof(set_buffer));
+	} else {
+		memset(&set_buffer, 0, sizeof(set_buffer));
+		printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
+			    " Misfeature support will be removed\n",
+			    current->comm);
+	}
 
 	error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
 	if (error || !ovalue)

kernel/time/Kconfig

@@ -1,6 +1,10 @@
 #
 # Timer subsystem related configuration options
 #
+
+# Core internal switch. Selected by NO_HZ / HIGH_RES_TIMERS. This is
+# only related to the tick functionality. Oneshot clockevent devices
+# are supported independ of this.
 config TICK_ONESHOT
 	bool
 

kernel/time/tick-broadcast.c

@@ -575,10 +575,12 @@ void tick_broadcast_switch_to_oneshot(void)
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
+
+	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
+
 	if (cpumask_empty(tick_get_broadcast_mask()))
 		goto end;
 
-	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
 	bc = tick_broadcast_device.evtdev;
 	if (bc)
 		tick_broadcast_setup_oneshot(bc);

kernel/time/tick-sched.c

@@ -534,9 +534,9 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
 				hrtimer_get_expires(&ts->sched_timer), 0))
 				break;
 		}
-		/* Update jiffies and reread time */
-		tick_do_update_jiffies64(now);
+		/* Reread time and update jiffies */
 		now = ktime_get();
+		tick_do_update_jiffies64(now);
 	}
 }