linux-toradex.git/drivers/base/cpu.c, branch v4.4-rc6

cpu: Remove bogus __ref annotation of cpu_subsys_online()

2015-08-05T22:18:26+00:00

In commit 0db0628d9012 ("kernel: delete __cpuinit usage from all core
kernel files") cpu_up() lost its __cpuinit annotation, vanishing the
need for cpu_subsys_online() to have a __ref annotation. Just drop it
to be able to catch real section mismatches in the future.

Signed-off-by: Mathias Krause 
Cc: Paul Gortmaker 
Signed-off-by: Greg Kroah-Hartman

show nohz_full cpus in sysfs

2015-05-20T07:15:09+00:00

Currently there is no way to query which CPUs are in nohz_full
mode from userspace.

Export the CPU list running in nohz_full mode in sysfs,
specifically in the file /sys/devices/system/cpu/nohz_full

This can be used by system management tools like libvirt,
openstack, and others to ensure proper task placement.

Signed-off-by: Rik van Riel 
Acked-by: Mike Galbraith 
Acked-by: Chris Metcalf 
Signed-off-by: Greg Kroah-Hartman

show isolated cpus in sysfs

2015-05-20T07:15:06+00:00

After system bootup, there is no totally reliable way to see
which CPUs are isolated, because the kernel may modify the
CPUs specified on the isolcpus= kernel command line option.

Export the CPU list that actually got isolated in sysfs,
specifically in the file /sys/devices/system/cpu/isolated

This can be used by system management tools like libvirt,
openstack, and others to ensure proper placement of tasks.

Suggested-by: Li Zefan 
Signed-off-by: Rik van Riel 
Acked-by: Mike Galbraith 
Acked-by: Chris Metcalf 
Signed-off-by: Greg Kroah-Hartman

drivers/base: use %*pb[l] to print bitmaps including cpumasks and nodemasks

2015-02-14T05:21:38+00:00

printk and friends can now format bitmaps using '%*pb[l]'.  cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr_args()
respectively which can be used to generate the two printf arguments
necessary to format the specified cpu/nodemask.

* Line termination only requires one extra space at the end of the
  buffer.  Use PAGE_SIZE - 1 instead of PAGE_SIZE - 2 when formatting.

Signed-off-by: Tejun Heo 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

drivers: base: add cpu_device_create to support per-cpu devices

2014-11-07T19:45:00+00:00

This patch adds a new function to create per-cpu devices.
This helps in:
1. reusing the device infrastructure to create any cpu related
   attributes and corresponding sysfs instead of creating and
   dealing with raw kobjects directly
2. retaining the legacy path(/sys/devices/system/cpu/..) to support
   existing sysfs ABI
3. avoiding to create links in the bus directory pointing to the
   device as there would be per-cpu instance of these devices with
   the same name since dev->bus is not populated to cpu_sysbus on
   purpose

Signed-off-by: Sudeep Holla 
Tested-by: Stephen Boyd 
Cc: Greg Kroah-Hartman 
Cc: David Herrmann 
Cc: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

cpumask: factor out show_cpumap into separate helper function

2014-11-07T19:45:00+00:00

Many sysfs *_show function use cpu{list,mask}_scnprintf to copy cpumap
to the buffer aligned to PAGE_SIZE, append '\n' and '\0' to return null
terminated buffer with newline.

This patch creates a new helper function cpumap_print_to_pagebuf in
cpumask.h using newly added bitmap_print_to_pagebuf and consolidates
most of those sysfs functions using the new helper function.

Signed-off-by: Sudeep Holla 
Suggested-by: Stephen Boyd 
Tested-by: Stephen Boyd 
Acked-by: "Rafael J. Wysocki" 
Acked-by: Bjorn Helgaas 
Acked-by: Peter Zijlstra (Intel) 
Cc: Greg Kroah-Hartman 
Cc: x86@kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

x86: align x86 arch with generic CPU modalias handling

2014-02-18T20:45:38+00:00

The x86 CPU feature modalias handling existed before it was reimplemented
generically. This patch aligns the x86 handling so that it
(a) reuses some more code that is now generic;
(b) uses the generic format for the modalias module metadata entry, i.e., it
    now uses 'cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:,XXXX,YYYY' instead of
    the 'x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:,XXXX,YYYY' that was
    used before.

Signed-off-by: Ard Biesheuvel 
Acked-by: H. Peter Anvin 
Signed-off-by: Greg Kroah-Hartman

cpu: add generic support for CPU feature based module autoloading

2014-02-18T20:38:37+00:00

This patch adds support for advertising optional CPU features over udev
using the modalias, and for declaring compatibility with/dependency upon
such a feature in a module.

The mapping between feature numbers and actual features should be provided
by the architecture in a file called  which exports the
following functions/macros:
- cpu_feature(FEAT), a preprocessor macro that maps token FEAT to a
  numeric index;
- bool cpu_have_feature(n), returning whether this CPU has support for
  feature #n;
- MAX_CPU_FEATURES, an upper bound for 'n' in the previous function.

The feature can then be enabled by setting CONFIG_GENERIC_CPU_AUTOPROBE
for the architecture.

For instance, a module that registers its module init function using

  module_cpu_feature_match(FEAT_X, module_init_function)

will be probed automatically when the CPU's support for the 'FEAT_X'
feature is advertised over udev, and will only allow the module to be
loaded by hand if the 'FEAT_X' feature is supported.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Greg Kroah-Hartman

hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock()

2013-09-30T17:55:51+00:00

cpu_hotplug_driver_lock() serializes CPU online/offline operations
when ARCH_CPU_PROBE_RELEASE is set.  This lock interface is no longer
necessary with the following reason:

 - lock_device_hotplug() now protects CPU online/offline operations,
   including the probe & release interfaces enabled by
   ARCH_CPU_PROBE_RELEASE.  The use of cpu_hotplug_driver_lock() is
   redundant.
 - cpu_hotplug_driver_lock() is only valid when ARCH_CPU_PROBE_RELEASE
   is defined, which is misleading and is only enabled on powerpc.

This patch removes the cpu_hotplug_driver_lock() interface.  As
a result, ARCH_CPU_PROBE_RELEASE only enables / disables the cpu
probe & release interface as intended.  There is no functional change
in this patch.

Signed-off-by: Toshi Kani 
Reviewed-by: Nathan Fontenot 
Signed-off-by: Rafael J. Wysocki

hotplug / x86: Add hotplug lock to missing places

2013-09-25T08:38:09+00:00

lock_device_hotplug[_sysfs]() serializes CPU & Memory online/offline
and hotplug operations.  However, this lock is not held in the debug
interfaces below that initiate CPU online/offline operations.

 - _debug_hotplug_cpu(), cpu0 hotplug test interface enabled by
   CONFIG_DEBUG_HOTPLUG_CPU0.
 - cpu_probe_store() and cpu_release_store(), cpu hotplug test interface
   enabled by CONFIG_ARCH_CPU_PROBE_RELEASE.

This patch changes the above interfaces to hold lock_device_hotplug().

Signed-off-by: Toshi Kani 
Acked-by: Greg Kroah-Hartman 
Acked-by: Yasuaki Ishimatsu 
Signed-off-by: Rafael J. Wysocki