This patch fixes following compiler warnings when build via make W=1:

drivers/acpi/processor_throttling.c: In function ‘acpi_processor_throttling_init’:
drivers/acpi/processor_throttling.c:216:40: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Using a u64 here creates an endian bug.  We store a u32 number in the
top byte which is a larger number than intended on big endian systems.
There is no reason to use a 64 bit data type here, I guess it was just
an oversight.

I removed the initialization to zero as well.  It's needed with a u64
but with a u32, the variable gets initialized properly inside the call
to acpi_os_read_port().

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Merge reason: Pick up the following two fix commits.

  2be19102b7: x86, NUMA: Fix empty memblk detection in numa_cleanup_meminfo()
  765af22da8: x86-32, NUMA: Fix ACPI NUMA init broken by recent x86-64 change

Scheduled NUMA init 32/64bit unification changes depend on these.

Signed-off-by: Tejun Heo <tj@kernel.org>

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

With the this_cpu_xx we no longer need to pass an acpi
structure to the msr management code. Simplifies code and improves
performance.

NOTE: This code is x86 specific (see #ifdef CONFIG_X86) but not under
      arch/x86.

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

After one CPU is offlined, it is unnecessary to switch T-state for it.
So it will be better that the throttling is disabled after the cpu
is offline.
At the same time after one cpu is online, we should check whether
the T-state is supported and then set the corresponding T-state
flag.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Now before it executes the T-state operation on one CPU, it will try to
migrate to the target CPU. Especially this is required on the system that
uses the MSR_IA32_THERMAL_CONTROL register to switch T-state.
But unfortunately it doesn't check whether the migration is successful or not.
In such case we will get/set the incorrect T-state on the offline CPU as
it fails in the migration to the offline CPU.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Remove deprecated ACPI process procfs I/F for throttling control.

This is because the t-state control should only be done in kernel,
when system is in a overheating state.

Now users can only change the processor t-state indirectly,
by poking the cooling device sysfs I/F of the processor.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

As a feature that would only be used when system is overheating,
the processor t-state control should not be exported to user space.
Make /proc/acpi/processor/*/throttle depends on CONFIG_ACPI_PROCFS,
which is cleared by default.
And we will remove this I/F in 2.6.38.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>