ARM: add cpufreq transiton notifier to adjust loops_per_jiffy for smp

If CONFIG_SMP, cpufreq skips loops_per_jiffy update, because different
arch has different per-cpu loops_per_jiffy definition.

Signed-off-by: Richard Zhao <richard.zhao@linaro.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
sched_avg: add run queue averaging.

Add code to calculate the run queue depth of a cpu and iowait
depth of the cpu.

The scheduler calls in to sched_update_nr_prod whenever there
is a runqueue change. This function maintains the runqueue average
and the iowait of that cpu in that time interval.

Whoever wants to know the runqueue average is expected to call
sched_get_nr_running_avg periodically to get the accumulated
runqueue and iowait averages for all the cpus.

Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org>
(cherry picked from commit 0299fcaaad80e2c0ac9aa583c95107f6edc27750)

Signed-off-by: Ram Kumar Chakravarthy Chebathini <rcheba@codeaurora.org>
(cherry picked from commit 5325d8a44f8296170cd8f42e245dd79f7b7347bf)

Change-Id: I92875789886c3f7c2457a063de4b3b6d8c893718
Signed-off-by: Sudhir Sharma <sudsha@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	include/linux/sched.h
ARM: smp: Fix cpu_up() racing with sys_reboot

Nothing stops a process from hotplugging in a CPU concurrently
with a sys_reboot() call. In such a situation we could have
ipi_cpu_stop() mark a cpu as 'offline' and _cpu_up() ignore the
fact that the CPU is not really offline and call the
CPU_UP_PREPARE notifier. When this happens stop_machine code will
complain that the cpu thread already exists and BUG_ON().

CPU0                      CPU1

sys_reboot()
 kernel_restart()
  machine_restart()
   machine_shutdown()
    smp_send_stop()
    ...                   ipi_cpu_stop()
                           set_cpu_online(1, false)
                            local_irq_disable()
                             while(1)
    <PREEMPT>
cpu_up()
 _cpu_up()
   if (!cpu_online(1))
    __cpu_notify(CPU_UP_PREPARE...)

cpu_stop_cpu_callback()
  BUG_ON(stopper->thread)

This is easily reproducible by hotplugging in and out in a tight
loop while also rebooting.

Since the CPU is not really offline and hasn't gone through the
proper steps to be marked as such, let's mark the CPU as inactive.
This is just as easily testable as online and avoids any possibility
of _cpu_up() trying to bring the CPU back online when it never was
offline to begin with.

Change-Id: Ia1daea407220578d4212ef6c65c4be837ca370fd
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
ARM: SoC: add per-platform SMP operations

This adds a 'struct smp_operations' to abstract the CPU initialization
and hot plugging functions on SMP systems, which otherwise conflict
in a multiplatform kernel. This also helps shmobile and potentially
others that have more than one method to do these.

To allow the kernel to continue building, the platform hooks are
defined as weak symbols which are overrided by the platform code.
Once all platforms are converted, the "weak" attribute will be
removed and the function made static.

Unlike the original version from Marc, this new version from Arnd
does not use a generalized abstraction for per-soc data structures
but only tries to solve the problem for the SMP operations. This
way, we can collapse the previous four data structures into a
single struct, which is less systematic but also easier to follow
as a causal reader.

Change-Id: I9d022d4e789f8f87f26a237fa2e9e410be070976
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[rameezmustafa@codeaurora.org: backport to kernel 3.4]
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	arch/arm/include/asm/mach/arch.h
	arch/arm/include/asm/smp.h
	arch/arm/kernel/smp.c
smp: fix derp.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
arm: Remove no-longer-required RCU_NONIDLE wrapper

Commit 21111be8 "ARM: Fix negative idle stats for offline cpu" moved call
to cpu_die() to occur outside of rcu_idle_enter()/rcu_idle_exit() section.
As a result, the RCU_NONIDLE() wrapper to complete() call in
arch/arm/kernel/process.c:cpu_die() is no longer required (and is
technically incorrect to have). Removing RCU_NONIDLE() wrapper also removes
this warning seen during CPU offline:

[Note: Below message has been edited to fit 75-char per line limit.
Insignificant portions of warning message has been removed in each line.]

------------[ cut here ]------------
WARNING: at kernel/rcutree.c:456 rcu_idle_exit_common+0x4c/0xe0()
Modules linked in:
(unwind_backtrace+0x0/0x120) from (warn_slowpath_common+0x4c/0x64)
(warn_slowpath_common+0x4c/0x64) from (warn_slowpath_null+0x18/0x1c)
(warn_slowpath_null+0x18/0x1c) from (rcu_idle_exit_common+0x4c/0xe0)
(rcu_idle_exit_common+0x4c/0xe0) from (rcu_idle_exit+0xa8/0xc0)
(rcu_idle_exit+0xa8/0xc0) from (cpu_die+0x24/0x5c)
(cpu_die+0x24/0x5c) from (cpu_idle+0xdc/0xf0)
(cpu_idle+0xdc/0xf0) from (0x8160)
---[ end trace 61bf21937a496a37 ]---

Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Change-Id: I721e6b20651674e6f6f584cf8d814af00b688c91
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>

Conflicts:
	arch/arm/kernel/smp.c