linux-toradex.git/drivers/acpi/processor_driver.c, branch v4.16-rc6

ACPI: processor: use dev_dbg() instead of dev_warn() when CPPC probe failed

2017-07-26T23:51:06+00:00

_CPC is a optinal object for processor device so it's
fine for processor devices in DSDT without CPPC data,
but when booting the system with CPPC enabled in the
kernel but without its support in the firmware, I got
lots of warnings on a 64 core system:

[    6.346016] acpi ACPI0007:00: CPPC data invalid or not present
[    6.346028] acpi ACPI0007:01: CPPC data invalid or not present
[    6.346039] acpi ACPI0007:02: CPPC data invalid or not present
[    6.346050] acpi ACPI0007:03: CPPC data invalid or not present
[    6.346063] acpi ACPI0007:04: CPPC data invalid or not present
...
[    6.346737] acpi ACPI0007:3f: CPPC data invalid or not present

This isn't much useful and a little bit noise, so
switch the dev_warn() to dev_dbg().

Signed-off-by: Hanjun Guo 
Signed-off-by: Rafael J. Wysocki

ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus()

2017-05-26T08:10:44+00:00

Converting the hotplug locking, i.e. get_online_cpus(), to a percpu rwsem
unearthed a circular lock dependency which was hidden from lockdep due to
the lockdep annotation of get_online_cpus() which prevents lockdep from
creating full dependency chains.

CPU0                    CPU1
----                    ----
lock((&wfc.work));
                         lock(cpu_hotplug_lock.rw_sem);
                         lock((&wfc.work));
lock(cpu_hotplug_lock.rw_sem);

This dependency is established via acpi_processor_start() which calls into
the work queue code. And the work queue code establishes the reverse
dependency.

This is not a problem of get_online_cpus() recursion, it's a possible
deadlock undetected by lockdep so far.

The cure is to use cpu_hotplug_disable() instead of get_online_cpus() to
protect the probing from acpi_processor_start().

There is a side effect to this: cpu_hotplug_disable() makes a concurrent
cpu hotplug attempt via the sysfs interfaces fail with -EBUSY, but that
probing usually happens during the boot process where no interaction is
possible. Any later invocations are infrequent enough and concurrent
hotplug attempts are so unlikely that the danger of user space visible
regressions is very close to zero. Anyway, thats preferrable over a real
deadlock.

Signed-off-by: Thomas Gleixner 
Acked-by: Ingo Molnar 
Acked-by: Rafael J. Wysocki 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Sebastian Siewior 
Cc: Steven Rostedt 
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown 
Link: http://lkml.kernel.org/r/20170524081548.851588594@linutronix.de

ACPI/processor: Replace racy task affinity logic

2017-04-15T10:20:54+00:00

acpi_processor_get_throttling() requires to invoke the getter function on
the target CPU. This is achieved by temporarily setting the affinity of the
calling user space thread to the requested CPU and reset it to the original
affinity afterwards.

That's racy vs. CPU hotplug and concurrent affinity settings for that
thread resulting in code executing on the wrong CPU and overwriting the
new affinity setting.

acpi_processor_get_throttling() is invoked in two ways:

1) The CPU online callback, which is already running on the target CPU and
   obviously protected against hotplug and not affected by affinity
   settings.

2) The ACPI driver probe function, which is not protected against hotplug
   during modprobe.

Switch it over to work_on_cpu() and protect the probe function against CPU
hotplug.

Signed-off-by: Thomas Gleixner 
Cc: Fenghua Yu 
Cc: Tony Luck 
Cc: Herbert Xu 
Cc: "Rafael J. Wysocki" 
Cc: Peter Zijlstra 
Cc: Benjamin Herrenschmidt 
Cc: Sebastian Siewior 
Cc: Lai Jiangshan 
Cc: linux-acpi@vger.kernel.org
Cc: Viresh Kumar 
Cc: Michael Ellerman 
Cc: Tejun Heo 
Cc: "David S. Miller" 
Cc: Len Brown 
Link: http://lkml.kernel.org/r/20170412201042.785920903@linutronix.de
Signed-off-by: Thomas Gleixner

ACPI/processor: Fix error handling in __acpi_processor_start()

2017-04-15T10:20:54+00:00

When acpi_install_notify_handler() fails the cooling device stays
registered and the sysfs files created via acpi_pss_perf_init() are
leaked and the function returns success.

Undo acpi_pss_perf_init() and return a proper error code.

Signed-off-by: Thomas Gleixner 
Cc: Fenghua Yu 
Cc: Tony Luck 
Cc: Herbert Xu 
Cc: "Rafael J. Wysocki" 
Cc: Peter Zijlstra 
Cc: Benjamin Herrenschmidt 
Cc: Sebastian Siewior 
Cc: Lai Jiangshan 
Cc: linux-acpi@vger.kernel.org
Cc: Viresh Kumar 
Cc: Michael Ellerman 
Cc: Tejun Heo 
Cc: "David S. Miller" 
Cc: Len Brown 
Link: http://lkml.kernel.org/r/20170412201042.695499645@linutronix.de
Signed-off-by: Thomas Gleixner

Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-10-04T02:43:08+00:00

Pull CPU hotplug updates from Thomas Gleixner:
 "Yet another batch of cpu hotplug core updates and conversions:

   - Provide core infrastructure for multi instance drivers so the
     drivers do not have to keep custom lists.

   - Convert custom lists to the new infrastructure. The block-mq custom
     list conversion comes through the block tree and makes the diffstat
     tip over to more lines removed than added.

   - Handle unbalanced hotplug enable/disable calls more gracefully.

   - Remove the obsolete CPU_STARTING/DYING notifier support.

   - Convert another batch of notifier users.

   The relayfs changes which conflicted with the conversion have been
   shipped to me by Andrew.

   The remaining lot is targeted for 4.10 so that we finally can remove
   the rest of the notifiers"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
  cpufreq: Fix up conversion to hotplug state machine
  blk/mq: Reserve hotplug states for block multiqueue
  x86/apic/uv: Convert to hotplug state machine
  s390/mm/pfault: Convert to hotplug state machine
  mips/loongson/smp: Convert to hotplug state machine
  mips/octeon/smp: Convert to hotplug state machine
  fault-injection/cpu: Convert to hotplug state machine
  padata: Convert to hotplug state machine
  cpufreq: Convert to hotplug state machine
  ACPI/processor: Convert to hotplug state machine
  virtio scsi: Convert to hotplug state machine
  oprofile/timer: Convert to hotplug state machine
  block/softirq: Convert to hotplug state machine
  lib/irq_poll: Convert to hotplug state machine
  x86/microcode: Convert to hotplug state machine
  sh/SH-X3 SMP: Convert to hotplug state machine
  ia64/mca: Convert to hotplug state machine
  ARM/OMAP/wakeupgen: Convert to hotplug state machine
  ARM/shmobile: Convert to hotplug state machine
  arm64/FP/SIMD: Convert to hotplug state machine
  ...

ACPI/processor: Convert to hotplug state machine

2016-09-19T19:44:29+00:00

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior 
Acked-by: "Rafael J. Wysocki" 
Cc: Peter Zijlstra 
Cc: linux-acpi@vger.kernel.org
Cc: rt@linutronix.de
Cc: Len Brown 
Link: http://lkml.kernel.org/r/20160906170457.32393-12-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner

ACPI / CPPC: Don't return on CPPC probe failure

2016-09-08T21:02:14+00:00

It is still possible to continue even CPPC data is invalid or missing.

Suggested-by: Alexey Klimov 
Signed-off-by: Srinivas Pandruvada 
Signed-off-by: Rafael J. Wysocki

ACPI / CPPC: Allow build with ACPI_CPU_FREQ_PSS config

2016-09-08T21:02:14+00:00

Some newer x86 platforms have support for both _CPC and _PSS object. So
kernel config can have both ACPI_CPU_FREQ_PSS and ACPI_CPPC_LIB. So remove
restriction for ACPI_CPPC_LIB to build only when ACPI_CPU_FREQ_PSS is not
defined.
Also for legacy systems with only _PSS, we shouldn't bail out if
acpi_cppc_processor_probe() fails, if ACPI_CPU_FREQ_PSS is also defined.

Signed-off-by: Srinivas Pandruvada 
Signed-off-by: Rafael J. Wysocki

Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-07-29T20:55:30+00:00

Pull smp hotplug updates from Thomas Gleixner:
 "This is the next part of the hotplug rework.

   - Convert all notifiers with a priority assigned

   - Convert all CPU_STARTING/DYING notifiers

     The final removal of the STARTING/DYING infrastructure will happen
     when the merge window closes.

  Another 700 hundred line of unpenetrable maze gone :)"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
  timers/core: Correct callback order during CPU hot plug
  leds/trigger/cpu: Move from CPU_STARTING to ONLINE level
  powerpc/numa: Convert to hotplug state machine
  arm/perf: Fix hotplug state machine conversion
  irqchip/armada: Avoid unused function warnings
  ARC/time: Convert to hotplug state machine
  clocksource/atlas7: Convert to hotplug state machine
  clocksource/armada-370-xp: Convert to hotplug state machine
  clocksource/exynos_mct: Convert to hotplug state machine
  clocksource/arm_global_timer: Convert to hotplug state machine
  rcu: Convert rcutree to hotplug state machine
  KVM/arm/arm64/vgic-new: Convert to hotplug state machine
  smp/cfd: Convert core to hotplug state machine
  x86/x2apic: Convert to CPU hotplug state machine
  profile: Convert to hotplug state machine
  timers/core: Convert to hotplug state machine
  hrtimer: Convert to hotplug state machine
  x86/tboot: Convert to hotplug state machine
  arm64/armv8 deprecated: Convert to hotplug state machine
  hwtracing/coresight-etm4x: Convert to hotplug state machine
  ...

ACPI / processor_idle: Add support for Low Power Idle(LPI) states

2016-07-21T21:25:58+00:00

ACPI 6.0 introduced an optional object _LPI that provides an alternate
method to describe Low Power Idle states. It defines the local power
states for each node in a hierarchical processor topology. The OSPM can
use _LPI object to select a local power state for each level of processor
hierarchy in the system. They used to produce a composite power state
request that is presented to the platform by the OSPM.

Since multiple processors affect the idle state for any non-leaf hierarchy
node, coordination of idle state requests between the processors is
required. ACPI supports two different coordination schemes: Platform
coordinated and  OS initiated.

This patch adds initial support for Platform coordination scheme of LPI.

Signed-off-by: Sudeep Holla 
Signed-off-by: Rafael J. Wysocki