timer: Prevent overflow in apply_slack

commit 98a01e779f3c66b0b11cd7e64d531c0e41c95762 upstream.

On architectures with sizeof(int) < sizeof (long), the
computation of mask inside apply_slack() can be undefined if the
computed bit is > 32.

E.g. with: expires = 0xffffe6f5 and slack = 25, we get:

expires_limit = 0x20000000e
bit = 33
mask = (1 << 33) - 1  /* undefined */

On x86, mask becomes 1 and and the slack is not applied properly.
On s390, mask is -1, expires is set to 0 and the timer fires immediately.

Use 1UL << bit to solve that issue.

Suggested-by: Deborah Townsend <dstownse@us.ibm.com>
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Link: http://lkml.kernel.org/r/20140418152310.GA13654@midget.suse.cz
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
add zen and make it default
cpuidle: Fix NULL pointer dereference during hotplug
cpuidle: make a single register function for all

The usual scheme to initialize a cpuidle driver on a SMP is:

	cpuidle_register_driver(drv);
	for_each_possible_cpu(cpu) {
		device = &per_cpu(cpuidle_dev, cpu);
		cpuidle_register_device(device);
	}

This code is duplicated in each cpuidle driver.

On UP systems, it is done this way:

	cpuidle_register_driver(drv);
	device = &per_cpu(cpuidle_dev, cpu);
	cpuidle_register_device(device);

On UP, the macro 'for_each_cpu' does one iteration:

        for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)

Hence, the initialization loop is the same for UP than SMP.

Beside, we saw different bugs / mis-initialization / return code
unchecked in
the different drivers, the code is duplicated including bugs. After
fixing all
these ones, it appears the initialization pattern is the same for
everyone.

Please note, some drivers are doing dev->state_count = drv->state_count.
This is
not necessary because it is done by the cpuidle_enable_device function
in the
cpuidle framework. This is true, until you have the same states for all
your
devices. Otherwise, the 'low level' API should be used instead with the
specific
initialization for the driver.

Let's add a wrapper function doing this initialization with a cpumask
parameter
for the coupled idle states and use it for all the drivers.

That will save a lot of LOC, consolidate the code, and the modifications
in the
future could be done in a single place. Another benefit is the
consolidation of
the cpuidle_device variable which is now in the cpuidle framework and no
longer
spread accross the different arch specific drivers.

Change-Id: I8f75188d5770871620f758c2973b74384ac570d5
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Karthik Parsha <kparsha@codeaurora.org>
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
random: speed up the fast_mix function by a factor of four (faux123)
disable auto_hotplug for now,the driver needs some work :/
cpufreq: interactive: handle errors from cpufreq_frequency_table_target

Add checks for error return from cpufreq_frequency_table_target, and be
less noisy on the existing call with an error check.  CPU hotplug and
system shutdown may cause this call to return -EINVAL.

Bug: 8613560
Change-Id: Id78d8829920462c0db1c7e14e717d91740d6cb44
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive: reduce chance of zero time delta on load eval

Reschedule load sampling timer after timestamp of sample start taken,
hold spinlock across entire sequence to avoid preemption.  Avoid the
WARN for zero time delta in the load sampling timer function.

Change-Id: Idc10a756f09141decb6df92669521a1ebf0dbc10
Signed-off-by: Todd Poynor <toddpoynor@google.com>
cpufreq: interactive: avoid underflow on active time calculation

Check for idle time delta less than elapsed time delta, avoid
underflow computing active time.

Change-Id: I3e4c6ef1ad794eec49ed379c0c50fa727fd6ad28
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
omapdss: remove warnings in gamma code
hrtimer: Consider preemption when migrating hrtimer cpu_bases

When switching to a new cpu_base in switch_hrtimer_base(), we
briefly enable preemption by unlocking the cpu_base lock in two
places. During this interval it's possible for the running thread
to be swapped to a different CPU.

Consider the following example:

CPU #0                                 CPU #1
----                                   ----
hrtimer_start()                        ...
 lock_hrtimer_base()
 switch_hrtimer_base()
  this_cpu = 0;
  target_cpu_base = 0;
  raw_spin_unlock(&cpu_base->lock)
<migrate to CPU 1>
...                                    this_cpu == 0
                                       cpu == this_cpu
                                       timer->base = CPU #0
                                       timer->base != LOCAL_CPU

Since the cached this_cpu is no longer accurate, we'll skip the
hrtimer_check_target() check. Once we eventually go to program
the hardware, we'll decide not to do so since it knows the real
CPU that we're running on is not the same as the chosen base. As
a consequence, we may end up missing the hrtimer's deadline.

Fix this by updating the local CPU number each time we retake a
cpu_base lock in switch_hrtimer_base().

Another possibility is to disable preemption across the whole of
switch_hrtimer_base.  This looks suboptimal since preemption
would be disabled while waiting for lock(s).

Change-Id: I3f76d528ab2288ef5f950f4d048e7f3fa6cf1228
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
hrtimer: Prevent enqueue of hrtimer on dead CPU

When switching the hrtimer cpu_base, we briefly allow for
preemption to become enabled by unlocking the cpu_base lock.
During this time, the CPU corresponding to the new cpu_base
that was selected may in fact go offline. In this scenario, the
hrtimer is enqueued to a CPU that's not online, and therefore
it never fires.

As an example, consider this example:

CPU #0                          CPU #1
----                            ----
...                             hrtimer_start()
                                 lock_hrtimer_base()
                                 switch_hrtimer_base()
                                  cpu = hrtimer_get_target() -> 1
                                  spin_unlock(&cpu_base->lock)
                                <migrate thread to CPU #0>
                                <offline>
spin_lock(&new_base->lock)
this_cpu = 0
cpu != this_cpu
enqueue_hrtimer(cpu_base #1)

To prevent this scenario, verify that the CPU corresponding to
the new cpu_base is indeed online before selecting it in
hrtimer_switch_base(). If it's not online, fallback to using the
base of the current CPU.

Change-Id: I6359cb299ba7e08abf25d3360fcdd925b4c03b69
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
add 224 mhz freq opp