ACPICA: Remove global option to serialize all control methods.

According to the reports, the "acpi_serialize" mechanism is broken as:

 A. The parallel method calls can still happen when the interpreter lock is
    released under the following conditions:
    1. External callbacks are invoked, for example, by the region handlers,
       the exception handlers, etc.;
    2. Module level execution is performed when Load/LoadTable opcodes are
       executed, and
    3. The _REG control methods are invoked to complete the region
       registrations.
 B. For the following situations, the interpreter lock need to be released
    even for a serialized method while currently, the lock-releasing
    operation is marked as a no-op by
    acpi_ex_relinquish/reacquire_interpreter() when this mechanism is
    enabled:
    1. Wait opcode is executed,
    2. Acquire opcode is executed, and
    3. Sleep opcode is executed.

This patch removes this mechanism and the internal
acpi_ex_relinquish/reacquire_interpreter() APIs.  Lv Zheng.

References: https://bugzilla.kernel.org/show_bug.cgi?id=52191
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA: Add auto-serialization support for ill-behaved control methods.

This change adds support to automatically mark a control method as
"serialized" if the method creates any named objects. This will
positively prevent the method from being entered by more than one
thread and thus preventing a possible abort when an attempt is
made to create an object twice.

Implemented by parsing all non-serialize control methods at table
load time.

This feature is disabled by default and this patch also adds a new
Linux kernel parameter "acpi_auto_serialize" to allow this feature
to be turned on for a specific boot.

References: https://bugzilla.kernel.org/show_bug.cgi?id=52191
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA: Add additional named objects for the auto-serialize method scan.

This change adds some additional opcodes that are detected and will
cause a method to be auto-serialized. These opcodes are the various
CreateXField and the FieldUnit opcodes. Lv Zheng.

References: https://bugzilla.kernel.org/show_bug.cgi?id=52191
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA: Ignore sync_level for methods that have been auto-serialized.

Cannot use a sync_level for methods that have been serialized at load-time
or runtime because this may interfere with any existing use of sync_levels
within the ASL code. So, we simply ignore the sync_level for these methods,
thus preserving any existing sync_level priorities. Note, the use of
sync_levels is actually rather rare within BIOS ASL code.

References: http://www.spinics.net/lists/linux-acpi/msg49496.html
Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Reported-by: Sabrina Dubroka <sd@queasysnail.net>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA: Enable auto-serialization as a default kernel behavior.

The previous commit "ACPICA: Add auto-serialization support for ill-behaved
control methods" introduced the auto-serialization facility as a workaround
that can be enabled by "acpi_auto_serialize":

This feature marks control methods that create named objects as "serialized"
to avoid unwanted AE_ALREADY_EXISTS control method evaluation failures.

Enable method auto-serialization as the default kernel behavior.  The new kernel
parameter is also changed from "acpi_auto_serialize" to "acpi_no_auto_serialize"
to reflect the default behavior.

References: https://bugzilla.kernel.org/show_bug.cgi?id=52191
References: http://www.spinics.net/lists/linux-acpi/msg49496.html
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpica' into bleeding-edge

* acpica:
  ACPICA: Enable auto-serialization as a default kernel behavior.
  ACPICA: Ignore sync_level for methods that have been auto-serialized.
  ACPICA: Add additional named objects for the auto-serialize method scan.
  ACPICA: Add auto-serialization support for ill-behaved control methods.
  ACPICA: Remove global option to serialize all control methods.
Revert "ACPI / processor: Make it possible to get APIC ID via GIC"

Revert commit df86f5df79d8 (ACPI / processor: Make it possible to get
APIC ID via GIC).

APIC ID refers the hardware ID of the CPU, which means MPIDR on
ARM/ARM64, but in ACPI 5.0, GIC ID feild in GIC structure have
no explicit definition and may not refer to the MPIDR.

Commit df86f5df79d8 assumed that gic->gic_id as MPIDR which may not be
the case, so revert it until the explicit definition of GIC structure
is ready.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'acpi-processor' into bleeding-edge

* acpi-processor:
  Revert "ACPI / processor: Make it possible to get APIC ID via GIC"
PM / Runtime: dev_pm_info.runtime_error is signed

dev_pm_info.runtime_error has always been a signed int, to store a signed
error code. Correct the documentation.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / Runtime: Split line longer than 80 characters

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / Runtime: Correct documented return values for generic PM callbacks

As of commit 05aa55dddb9ee4045c320661068bea78dad6a6e5 ("PM / Runtime:
Lenient generic runtime pm callbacks"), the generic power management
callbacks pm_generic_runtime_suspend() and pm_generic_runtime_resume()
return 0, not -EINVAL, if the device doesn't provide its own callbacks.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / Runtime: GENERIC_SUBSYS_PM_OPS is gone

Update the documentation for the removal of GENERIC_SUBSYS_PM_OPS in commit
90363ddf0a1a4dccfbb8d0c10b8f488bc7fa69f8 ("PM: Drop generic_subsys_pm_ops")

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / Runtime: s/foo_process_requests/foo_process_next_request/

The example uses foo_process_next_request() everywhere else.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PM / Runtime: Spelling s/competing/completing/

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-runtime' into bleeding-edge

* pm-runtime:
  PM / Runtime: Spelling s/competing/completing/
  PM / Runtime: s/foo_process_requests/foo_process_next_request/
  PM / Runtime: GENERIC_SUBSYS_PM_OPS is gone
  PM / Runtime: Correct documented return values for generic PM callbacks
  PM / Runtime: Split line longer than 80 characters
  PM / Runtime: dev_pm_info.runtime_error is signed
cpufreq: resume drivers before enabling governors

During suspend, we first stop governors and then suspend cpufreq drivers and
resume must be exactly opposite of that. i.e. resume drivers first and then
start governors.

But the current code in resume enables governors first and then resume drivers.
Fix it be changing code sequence there.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
intel_pstate: Use del_timer_sync in intel_pstate_cpu_stop

Ensure that no timer callback is running since we are about to free
the timer structure.  We cannot guarantee that the call back is called
on the CPU where the timer is running.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Make sure frequency transitions are serialized

Whenever we change the frequency of a CPU, we call the PRECHANGE and POSTCHANGE
notifiers. They must be serialized, i.e. PRECHANGE and POSTCHANGE notifiers
should strictly alternate, thereby preventing two different sets of PRECHANGE or
POSTCHANGE notifiers from interleaving arbitrarily.

The following examples illustrate why this is important:

Scenario 1:
-----------
A thread reading the value of cpuinfo_cur_freq, will call
__cpufreq_cpu_get()->cpufreq_out_of_sync()->cpufreq_notify_transition()

The ondemand governor can decide to change the frequency of the CPU at the same
time and hence it can end up sending the notifications via ->target().

If the notifiers are not serialized, the following sequence can occur:
- PRECHANGE Notification for freq A (from cpuinfo_cur_freq)
- PRECHANGE Notification for freq B (from target())
- Freq changed by target() to B
- POSTCHANGE Notification for freq B
- POSTCHANGE Notification for freq A

We can see from the above that the last POSTCHANGE Notification happens for freq
A but the hardware is set to run at freq B.

Where would we break then?: adjust_jiffies() in cpufreq.c & cpufreq_callback()
in arch/arm/kernel/smp.c (which also adjusts the jiffies). All the
loops_per_jiffy calculations will get messed up.

Scenario 2:
-----------
The governor calls __cpufreq_driver_target() to change the frequency. At the
same time, if we change scaling_{min|max}_freq from sysfs, it will end up
calling the governor's CPUFREQ_GOV_LIMITS notification, which will also call
__cpufreq_driver_target(). And hence we end up issuing concurrent calls to
->target().

Typically, platforms have the following logic in their ->target() routines:
(Eg: cpufreq-cpu0, omap, exynos, etc)

A. If new freq is more than old: Increase voltage
B. Change freq
C. If new freq is less than old: decrease voltage

Now, if the two concurrent calls to ->target() are X and Y, where X is trying to
increase the freq and Y is trying to decrease it, we get the following race
condition:

X.A: voltage gets increased for larger freq
Y.A: nothing happens
Y.B: freq gets decreased
Y.C: voltage gets decreased
X.B: freq gets increased
X.C: nothing happens

Thus we can end up setting a freq which is not supported by the voltage we have
set. That will probably make the clock to the CPU unstable and the system might
not work properly anymore.

This patch introduces a set of synchronization primitives to serialize frequency
transitions, which are to be used as shown below:

cpufreq_freq_transition_begin();

//Perform the frequency change

cpufreq_freq_transition_end();

The _begin() call sends the PRECHANGE notification whereas the _end() call sends
the POSTCHANGE notification. Also, all the necessary synchronization is handled
within these calls. In particular, even drivers which set the ASYNC_NOTIFICATION
flag can also use these APIs for performing frequency transitions (ie., you can
call _begin() from one task, and call the corresponding _end() from a different
task).

The actual synchronization underneath is not that complicated:

The key challenge is to allow drivers to begin the transition from one thread
and end it in a completely different thread (this is to enable drivers that do
asynchronous POSTCHANGE notification from bottom-halves, to also use the same
interface).

To achieve this, a 'transition_ongoing' flag, a 'transition_lock' spinlock and a
wait-queue are added per-policy. The flag and the wait-queue are used in
conjunction to create an "uninterrupted flow" from _begin() to _end(). The
spinlock is used to ensure that only one such "flow" is in flight at any given
time. Put together, this provides us all the necessary synchronization.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end}

CPUFreq core has new infrastructure that would guarantee serialized calls to
target() or target_index() callbacks. These are called
cpufreq_freq_transition_begin() and cpufreq_freq_transition_end().

This patch converts existing drivers to use these new set of routines.

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Make cpufreq_notify_transition & cpufreq_notify_post_transition static

cpufreq_notify_transition() and cpufreq_notify_post_transition() shouldn't be
called directly by cpufreq drivers anymore and so these should be marked static.

Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>