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641 commits

Author SHA1 Message Date
Valentin Schneider
ecddc3a0d5 arch_topology, cpufreq: constify arch_* cpumasks
The passed cpumask arguments to arch_set_freq_scale() and
arch_freq_counters_available() are only iterated over, so reflect this
in the prototype. This also allows to pass system cpumasks like
cpu_online_mask without getting a warning.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-09-18 19:11:04 +02:00
Ionela Voinescu
874f635310 cpufreq: report whether cpufreq supports Frequency Invariance (FI)
Now that the update of the FI scale factor is done in cpufreq core for
selected functions - target(), target_index() and fast_switch(),
we can provide feedback to the task scheduler and architecture code
on whether cpufreq supports FI.

For this purpose provide an external function to expose whether the
cpufreq drivers support FI, by using a static key.

The logic behind the enablement of cpufreq-based invariance is as
follows:
 - cpufreq-based invariance is disabled by default
 - cpufreq-based invariance is enabled if any of the callbacks
   above is implemented while the unsupported setpolicy() is not

The cpufreq_supports_freq_invariance() function only returns whether
cpufreq is instrumented with the arch_set_freq_scale() calls that
result in support for frequency invariance. Due to the lack of knowledge
on whether the implementation of arch_set_freq_scale() actually results
in the setting of a scale factor based on cpufreq information, it is up
to the architecture code to ensure the setting and provision of the
scale factor to the scheduler.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-09-18 19:10:56 +02:00
Ionela Voinescu
1a0419b0db cpufreq: move invariance setter calls in cpufreq core
To properly scale its per-entity load-tracking signals, the task scheduler
needs to be given a frequency scale factor, i.e. some image of the current
frequency the CPU is running at. Currently, this scale can be computed
either by using counters (APERF/MPERF on x86, AMU on arm64), or by
piggy-backing on the frequency selection done by cpufreq.

For the latter, drivers have to explicitly set the scale factor
themselves, despite it being purely boiler-plate code: the required
information depends entirely on the kind of frequency switch callback
implemented by the driver, i.e. either of: target_index(), target(),
fast_switch() and setpolicy().

The fitness of those callbacks with regard to driving the Frequency
Invariance Engine (FIE) is studied below:

target_index()
==============
Documentation states that the chosen frequency "must be determined by
freq_table[index].frequency". It isn't clear if it *has* to be that
frequency, or if it can use that frequency value to do some computation
that ultimately leads to a different frequency selection. All drivers
go for the former, while the vexpress-spc-cpufreq has an atypical
implementation which is handled separately.

Therefore, the hook works on the assumption the core can use
freq_table[index].frequency.

target()
=======
This has been flagged as deprecated since:

  commit 9c0ebcf78f ("cpufreq: Implement light weight ->target_index() routine")

It also doesn't have that many users:

  gx-suspmod.c:439:       .target = cpufreq_gx_target,
  s3c24xx-cpufreq.c:428:  .target = s3c_cpufreq_target,
  intel_pstate.c:2528:    .target = intel_cpufreq_target,
  cppc_cpufreq.c:401:     .target = cppc_cpufreq_set_target,
  cpufreq-nforce2.c:371:  .target = nforce2_target,
  sh-cpufreq.c:163:       .target = sh_cpufreq_target,
  pcc-cpufreq.c:573:      .target = pcc_cpufreq_target,

Similarly to the path taken for target_index() calls in the cpufreq core
during a frequency change, all of the drivers above will mark the end of a
frequency change by a call to cpufreq_freq_transition_end().

Therefore, cpufreq_freq_transition_end() can be used as the location for
the arch_set_freq_scale() call to potentially inform the scheduler of the
frequency change.

This change maintains the previous functionality for the drivers that
implement the target_index() callback, while also adding support for the
few drivers that implement the deprecated target() callback.

fast_switch()
=============
This callback *has* to return the frequency that was selected.

setpolicy()
===========
This callback does not have any designated way of informing what was the
end choice. But there are only two drivers using setpolicy(), and none
of them have current FIE support:

  drivers/cpufreq/longrun.c:281:	.setpolicy	= longrun_set_policy,
  drivers/cpufreq/intel_pstate.c:2215:	.setpolicy	= intel_pstate_set_policy,

The intel_pstate is known to use counter-driven frequency invariance.

Conclusion
==========

Given that the significant majority of current FIE enabled drivers use
callbacks that lend themselves to triggering the setting of the FIE scale
factor in a generic way, move the invariance setter calls to cpufreq core.

As a result of setting the frequency scale factor in cpufreq core, after
callbacks that lend themselves to trigger it, remove this functionality
from the driver side.

To be noted that despite marking a successful frequency change, many
cpufreq drivers will consider the new frequency as the requested
frequency, although this is might not be the one granted by the hardware.

Therefore, the call to arch_set_freq_scale() is a "best effort" one, and
it is up to the architecture if the new frequency is used in the new
frequency scale factor setting (determined by the implementation of
arch_set_freq_scale()) or eventually used by the scheduler (determined
by the implementation of arch_scale_freq_capacity()). The architecture
is in a better position to decide if it has better methods to obtain
more accurate information regarding the current frequency and use that
information instead (for example, the use of counters).

Also, the implementation to arch_set_freq_scale() will now have to handle
error conditions (current frequency == 0) in order to prevent the
overhead in cpufreq core when the default arch_set_freq_scale()
implementation is used.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Suggested-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-09-18 19:10:42 +02:00
Viresh Kumar
681fe68448 cpufreq: No need to verify cpufreq_driver in show_scaling_cur_freq()
"cpufreq_driver" is guaranteed to be valid here, no need to check it
here.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-08-27 12:51:25 +02:00
Rafael J. Wysocki
f6ebbcf08f cpufreq: intel_pstate: Implement passive mode with HWP enabled
Allow intel_pstate to work in the passive mode with HWP enabled and
make it set the HWP minimum performance limit (HWP floor) to the
P-state value given by the target frequency supplied by the cpufreq
governor, so as to prevent the HWP algorithm and the CPU scheduler
from working against each other, at least when the schedutil governor
is in use, and update the intel_pstate documentation accordingly.

Among other things, this allows utilization clamps to be taken
into account, at least to a certain extent, when intel_pstate is
in use and makes it more likely that sufficient capacity for
deadline tasks will be provided.

After this change, the resulting behavior of an HWP system with
intel_pstate in the passive mode should be close to the behavior
of the analogous non-HWP system with intel_pstate in the passive
mode, except that the HWP algorithm is generally allowed to make the
CPU run at a frequency above the floor P-state set by intel_pstate in
the entire available range of P-states, while without HWP a CPU can
run in a P-state above the requested one if the latter falls into the
range of turbo P-states (referred to as the turbo range) or if the
P-states of all CPUs in one package are coordinated with each other
at the hardware level.

[Note that in principle the HWP floor may not be taken into account
 by the processor if it falls into the turbo range, in which case the
 processor has a license to choose any P-state, either below or above
 the HWP floor, just like a non-HWP processor in the case when the
 target P-state falls into the turbo range.]

With this change applied, intel_pstate in the passive mode assumes
complete control over the HWP request MSR and concurrent changes of
that MSR (eg. via the direct MSR access interface) are overridden by
it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
2020-08-11 17:29:45 +02:00
Rafael J. Wysocki
9ac1fb156a Merge branch 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm
Pull ARM cpufreq driver changes for v5.9-rc1 from Viresh Kumar:

"Here are the details:

- Adaptive voltage scaling (AVS) support and minor cleanups for
  brcmstb driver (Florian Fainelli and Markus Mayer).

- A new tegra driver and cleanup for the existing one (Sumit Gupta and
  Jon Hunter).

- Bandwidth level support for Qcom driver along with OPP changes (Sibi
  Sankar).

- Cleanups to sti, cpufreq-dt, ap806, CPPC drivers (Viresh Kumar, Lee
  Jones, Ivan Kokshaysky, Sven Auhagen, and Xin Hao).

- Make schedutil default governor for ARM (Valentin Schneider).

- Fix dependency issues for imx (Walter Lozano).

- Cleanup around cached_resolved_idx in cpufreq core (Viresh Kumar)."

* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
  cpufreq: make schedutil the default for arm and arm64
  cpufreq: cached_resolved_idx can not be negative
  cpufreq: Add Tegra194 cpufreq driver
  dt-bindings: arm: Add NVIDIA Tegra194 CPU Complex binding
  cpufreq: imx: Select NVMEM_IMX_OCOTP
  cpufreq: sti-cpufreq: Fix some formatting and misspelling issues
  cpufreq: tegra186: Simplify probe return path
  cpufreq: CPPC: Reuse caps variable in few routines
  cpufreq: ap806: fix cpufreq driver needs ap cpu clk
  cpufreq: cppc: Reorder code and remove apply_hisi_workaround variable
  cpufreq: dt: fix oops on armada37xx
  cpufreq: brcmstb-avs-cpufreq: send S2_ENTER / S2_EXIT commands to AVS
  cpufreq: brcmstb-avs-cpufreq: Support polling AVS firmware
  cpufreq: brcmstb-avs-cpufreq: more flexible interface for __issue_avs_command()
  cpufreq: qcom: Disable fast switch when scaling DDR/L3
  cpufreq: qcom: Update the bandwidth levels on frequency change
  OPP: Add and export helper to set bandwidth
  cpufreq: blacklist SC7180 in cpufreq-dt-platdev
  cpufreq: blacklist SDM845 in cpufreq-dt-platdev
2020-08-04 12:44:53 +02:00
Viresh Kumar
292072c387 cpufreq: cached_resolved_idx can not be negative
It is not possible for cached_resolved_idx to be invalid here as the
cpufreq core always sets index to a positive value.

Change its type to unsigned int and fix qcom usage a bit.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-07-30 11:40:16 +05:30
Lee Jones
a9909c217f cpufreq: cpufreq: Demote lots of function headers unworthy of kerneldoc status
Also provide missing function parameter description for 'cpu' and 'policy'.

Fixes the following W=1 kernel build warning(s):

 drivers/cpufreq/cpufreq.c:60: warning: cannot understand function prototype: 'struct cpufreq_driver *cpufreq_driver; '
 drivers/cpufreq/cpufreq.c:90: warning: Function parameter or member 'cpufreq_policy_notifier_list' not described in 'BLOCKING_NOTIFIER_HEAD'
 drivers/cpufreq/cpufreq.c:312: warning: Function parameter or member 'val' not described in 'adjust_jiffies'
 drivers/cpufreq/cpufreq.c:312: warning: Function parameter or member 'ci' not described in 'adjust_jiffies'
 drivers/cpufreq/cpufreq.c:538: warning: Function parameter or member 'policy' not described in 'cpufreq_driver_resolve_freq'
 drivers/cpufreq/cpufreq.c:686: warning: Function parameter or member 'file_name' not described in 'show_one'
 drivers/cpufreq/cpufreq.c:686: warning: Function parameter or member 'object' not described in 'show_one'
 drivers/cpufreq/cpufreq.c:731: warning: Function parameter or member 'file_name' not described in 'store_one'
 drivers/cpufreq/cpufreq.c:731: warning: Function parameter or member 'object' not described in 'store_one'
 drivers/cpufreq/cpufreq.c:741: warning: Function parameter or member 'policy' not described in 'show_cpuinfo_cur_freq'
 drivers/cpufreq/cpufreq.c:741: warning: Function parameter or member 'buf' not described in 'show_cpuinfo_cur_freq'
 drivers/cpufreq/cpufreq.c:754: warning: Function parameter or member 'policy' not described in 'show_scaling_governor'
 drivers/cpufreq/cpufreq.c:754: warning: Function parameter or member 'buf' not described in 'show_scaling_governor'
 drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'policy' not described in 'store_scaling_governor'
 drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'buf' not described in 'store_scaling_governor'
 drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'count' not described in 'store_scaling_governor'
 drivers/cpufreq/cpufreq.c:806: warning: Function parameter or member 'policy' not described in 'show_scaling_driver'
 drivers/cpufreq/cpufreq.c:806: warning: Function parameter or member 'buf' not described in 'show_scaling_driver'
 drivers/cpufreq/cpufreq.c:815: warning: Function parameter or member 'policy' not described in 'show_scaling_available_governors'
 drivers/cpufreq/cpufreq.c:815: warning: Function parameter or member 'buf' not described in 'show_scaling_available_governors'
 drivers/cpufreq/cpufreq.c:859: warning: Function parameter or member 'policy' not described in 'show_related_cpus'
 drivers/cpufreq/cpufreq.c:859: warning: Function parameter or member 'buf' not described in 'show_related_cpus'
 drivers/cpufreq/cpufreq.c:867: warning: Function parameter or member 'policy' not described in 'show_affected_cpus'
 drivers/cpufreq/cpufreq.c:867: warning: Function parameter or member 'buf' not described in 'show_affected_cpus'
 drivers/cpufreq/cpufreq.c:901: warning: Function parameter or member 'policy' not described in 'show_bios_limit'
 drivers/cpufreq/cpufreq.c:901: warning: Function parameter or member 'buf' not described in 'show_bios_limit'
 drivers/cpufreq/cpufreq.c:1625: warning: Function parameter or member 'dev' not described in 'cpufreq_remove_dev'
 drivers/cpufreq/cpufreq.c:1625: warning: Function parameter or member 'sif' not described in 'cpufreq_remove_dev'
 drivers/cpufreq/cpufreq.c:2380: warning: Function parameter or member 'cpu' not described in 'cpufreq_get_policy'
 drivers/cpufreq/cpufreq.c:2771: warning: Function parameter or member 'driver' not described in 'cpufreq_unregister_driver'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-15 15:17:06 +02:00
Viresh Kumar
3a7e4fbbfd cpufreq: Remove the weakly defined cpufreq_default_governor()
The default cpufreq governor is chosen with the help of a "choice"
option in the Kconfig which will always end up selecting one of
the governors and so the weakly defined definition of
cpufreq_default_governor() will never get called.

Moreover, this makes us skip the checking of the return value of
that routine as it will always be non NULL.

If the Kconfig option changes in future, then we will start getting
a link error instead (and it won't go unnoticed as in the case of the
weak definition).

Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-02 13:03:31 +02:00
Quentin Perret
8412b4563e cpufreq: Specify default governor on command line
Currently, the only way to specify the default CPUfreq governor is
via Kconfig options, which suits users who can build the kernel
themselves perfectly.

However, for those who use a distro-like kernel (such as Android,
with the Generic Kernel Image project), the only way to use a
non-default governor is to boot to userspace, and to then switch
using the sysfs interface. Being able to specify the default governor
on the command line, like is the case for cpuidle, would allow those
users to specify their governor of choice earlier on, and to simplify
the userspace boot procedure slighlty.

To support this use-case, add a kernel command line parameter
allowing the default governor for CPUfreq to be specified, which
takes precedence over the built-in default.

This implementation has one notable limitation: the default governor
must be registered before the driver. This is solved for builtin
governors and drivers using appropriate *_initcall() functions. And
in the modular case, this must be reflected as a constraint on the
module loading order.

Signed-off-by: Quentin Perret <qperret@google.com>
[ Viresh: Converted 'default_governor' to a string and parsing it only
	  at initcall level, and several updates to
	  cpufreq_init_policy(). ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-02 13:03:30 +02:00
Viresh Kumar
8cc46ae565 cpufreq: Fix locking issues with governors
The locking around governors handling isn't adequate currently.

The list of governors should never be traversed without the locking
in place. Also governor modules must not be removed while the code
in them is still in use.

Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-02 13:02:55 +02:00
Xiongfeng Wang
cf6fada715 cpufreq: change '.set_boost' to act on one policy
Macro 'for_each_active_policy()' is defined internally. To avoid some
cpufreq driver needing this macro to iterate over all the policies in
'.set_boost' callback, we redefine '.set_boost' to act on only one
policy and pass the policy as an argument.

'cpufreq_boost_trigger_state()' iterates over all the policies to set
boost for the system.

This is preparation for adding SW BOOST support for CPPC.

To protect Boost enable/disable by sysfs from CPU online/offline,
add 'cpu_hotplug_lock' before calling '.set_boost' for each CPU.

Also move the lock from 'set_boost()' to 'store_cpb()' in
acpi_cpufreq.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-06-05 14:20:02 +02:00
Rafael J. Wysocki
552abb884e cpufreq: Fix up cpufreq_boost_set_sw()
After commit 18c49926c4 ("cpufreq: Add QoS requests for userspace
constraints") the return value of freq_qos_update_request(), that can
be 1, passed by cpufreq_boost_set_sw() to its caller sometimes
confuses the latter, which only expects to see 0 or negative error
codes, so notice that cpufreq_boost_set_sw() can return an error code
(which should not be -EINVAL for that matter) as soon as the first
policy without a frequency table is found (because either all policies
have a frequency table or none of them have it) and rework it to meet
its caller's expectations.

Fixes: 18c49926c4 ("cpufreq: Add QoS requests for userspace constraints")
Reported-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reported-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 5.3+ <stable@vger.kernel.org> # 5.3+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-05-18 13:01:28 +02:00
Linus Torvalds
3cd86a58f7 arm64 updates for 5.7:
- In-kernel Pointer Authentication support (previously only offered to
   user space).
 
 - ARM Activity Monitors (AMU) extension support allowing better CPU
   utilisation numbers for the scheduler (frequency invariance).
 
 - Memory hot-remove support for arm64.
 
 - Lots of asm annotations (SYM_*) in preparation for the in-kernel
   Branch Target Identification (BTI) support.
 
 - arm64 perf updates: ARMv8.5-PMU 64-bit counters, refactoring the PMU
   init callbacks, support for new DT compatibles.
 
 - IPv6 header checksum optimisation.
 
 - Fixes: SDEI (software delegated exception interface) double-lock on
   hibernate with shared events.
 
 - Minor clean-ups and refactoring: cpu_ops accessor, cpu_do_switch_mm()
   converted to C, cpufeature finalisation helper.
 
 - sys_mremap() comment explaining the asymmetric address untagging
   behaviour.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "The bulk is in-kernel pointer authentication, activity monitors and
  lots of asm symbol annotations. I also queued the sys_mremap() patch
  commenting the asymmetry in the address untagging.

  Summary:

   - In-kernel Pointer Authentication support (previously only offered
     to user space).

   - ARM Activity Monitors (AMU) extension support allowing better CPU
     utilisation numbers for the scheduler (frequency invariance).

   - Memory hot-remove support for arm64.

   - Lots of asm annotations (SYM_*) in preparation for the in-kernel
     Branch Target Identification (BTI) support.

   - arm64 perf updates: ARMv8.5-PMU 64-bit counters, refactoring the
     PMU init callbacks, support for new DT compatibles.

   - IPv6 header checksum optimisation.

   - Fixes: SDEI (software delegated exception interface) double-lock on
     hibernate with shared events.

   - Minor clean-ups and refactoring: cpu_ops accessor,
     cpu_do_switch_mm() converted to C, cpufeature finalisation helper.

   - sys_mremap() comment explaining the asymmetric address untagging
     behaviour"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (81 commits)
  mm/mremap: Add comment explaining the untagging behaviour of mremap()
  arm64: head: Convert install_el2_stub to SYM_INNER_LABEL
  arm64: Introduce get_cpu_ops() helper function
  arm64: Rename cpu_read_ops() to init_cpu_ops()
  arm64: Declare ACPI parking protocol CPU operation if needed
  arm64: move kimage_vaddr to .rodata
  arm64: use mov_q instead of literal ldr
  arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH
  lkdtm: arm64: test kernel pointer authentication
  arm64: compile the kernel with ptrauth return address signing
  kconfig: Add support for 'as-option'
  arm64: suspend: restore the kernel ptrauth keys
  arm64: __show_regs: strip PAC from lr in printk
  arm64: unwind: strip PAC from kernel addresses
  arm64: mask PAC bits of __builtin_return_address
  arm64: initialize ptrauth keys for kernel booting task
  arm64: initialize and switch ptrauth kernel keys
  arm64: enable ptrauth earlier
  arm64: cpufeature: handle conflicts based on capability
  arm64: cpufeature: Move cpu capability helpers inside C file
  ...
2020-03-31 10:05:01 -07:00
Ionela Voinescu
bbce8eaa60 cpufreq: add function to get the hardware max frequency
Add weak function to return the hardware maximum frequency of a CPU,
with the default implementation returning cpuinfo.max_freq, which is
the best information we can generically get from the cpufreq framework.

The default can be overwritten by a strong function in platforms
that want to provide an alternative implementation, with more accurate
information, obtained either from hardware or firmware.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-03-06 16:02:50 +00:00
Rafael J. Wysocki
f5739cb0b5 cpufreq: Fix policy initialization for internal governor drivers
Before commit 1e4f63aecb ("cpufreq: Avoid creating excessively
large stack frames") the initial value of the policy field in struct
cpufreq_policy set by the driver's ->init() callback was implicitly
passed from cpufreq_init_policy() to cpufreq_set_policy() if the
default governor was neither "performance" nor "powersave".  After
that commit, however, cpufreq_init_policy() must take that case into
consideration explicitly and handle it as appropriate, so make that
happen.

Fixes: 1e4f63aecb ("cpufreq: Avoid creating excessively large stack frames")
Link: https://lore.kernel.org/linux-pm/39fb762880c27da110086741315ca8b111d781cd.camel@gmail.com/
Reported-by: Artem Bityutskiy <dedekind1@gmail.com>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-02-27 08:57:48 +01:00
Yangtao Li
183edb20e6 cpufreq: Make cpufreq_global_kobject static
The cpufreq_global_kobject is only used internally by cpufreq.c
after commit 2361be2366 ("cpufreq: Don't create empty
/sys/devices/system/cpu/cpufreq directory").

Make it static.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
[ rjw: Add empty line after cpufreq_global_kobject definition ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-02-03 16:56:48 +01:00
Rafael J. Wysocki
1e4f63aecb cpufreq: Avoid creating excessively large stack frames
In the process of modifying a cpufreq policy, the cpufreq core makes
a copy of it including all of the internals which is stored on the
CPU stack.  Because struct cpufreq_policy is relatively large, this
may cause the size of the stack frame to exceed the 2 KB limit and
so the GCC complains when -Wframe-larger-than= is used.

In fact, it is not necessary to copy the entire policy structure
in order to modify it, however.

First, because cpufreq_set_policy() obtains the min and max policy
limits from frequency QoS now, it is not necessary to pass the limits
to it from the callers.  The only things that need to be passed to it
from there are the new governor pointer or (if there is a built-in
governor in the driver) the "policy" value representing the governor
choice.  They both can be passed as individual arguments, though, so
make cpufreq_set_policy() take them this way and rework its callers
accordingly.  This avoids making copies of cpufreq policies in the
callers of cpufreq_set_policy().

Second, cpufreq_set_policy() still needs to pass the new policy
data to the ->verify() callback of the cpufreq driver whose task
is to sanitize the min and max policy limits.  It still does not
need to make a full copy of struct cpufreq_policy for this purpose,
but it needs to pass a few items from it to the driver in case they
are needed (different drivers have different needs in that respect
and all of them have to be covered).  For this reason, introduce
struct cpufreq_policy_data to hold copies of the members of
struct cpufreq_policy used by the existing ->verify() driver
callbacks and pass a pointer to a temporary structure of that
type to ->verify() (instead of passing a pointer to full struct
cpufreq_policy to it).

While at it, notice that intel_pstate and longrun don't really need
to verify the "policy" value in struct cpufreq_policy, so drop those
check from them to avoid copying "policy" into struct
cpufreq_policy_data (which allows it to be slightly smaller).

Also while at it fix up white space in a couple of places and make
cpufreq_set_policy() static (as it can be so).

Fixes: 3000ce3c52 ("cpufreq: Use per-policy frequency QoS")
Link: https://lore.kernel.org/linux-pm/CAMuHMdX6-jb1W8uC2_237m8ctCpsnGp=JCxqt8pCWVqNXHmkVg@mail.gmail.com
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-01-27 10:33:33 +01:00
Linus Torvalds
9e7a03233e Power management updates for 5.5-rc1
- Use nanoseconds (instead of microseconds) as the unit of time in
    the cpuidle core and simplify checks for disabled idle states in
    the idle loop (Rafael Wysocki).
 
  - Fix and clean up the teo cpuidle governor (Rafael Wysocki).
 
  - Fix the cpuidle registration error code path (Zhenzhong Duan).
 
  - Avoid excessive vmexits in the ACPI cpuidle driver (Yin Fengwei).
 
  - Extend the idle injection infrastructure to be able to measure the
    requested duration in nanoseconds and to allow an exit latency
    limit for idle states to be specified (Daniel Lezcano).
 
  - Fix cpufreq driver registration and clarify a comment in the
    cpufreq core (Viresh Kumar).
 
  - Add NULL checks to the show() and store() methods of sysfs
    attributes exposed by cpufreq (Kai Shen).
 
  - Update cpufreq drivers:
 
    * Fix for a plain int as pointer warning from sparse in
      intel_pstate (Jamal Shareef).
 
    * Fix for a hardcoded number of CPUs and stack bloat in the
      powernv driver (John Hubbard).
 
    * Updates to the ti-cpufreq driver and DT files to support new
      platforms and migrate bindings from opp-v1 to opp-v2 (Adam Ford,
      H. Nikolaus Schaller).
 
    * Merging of the arm_big_little and vexpress-spc drivers and
      related cleanup (Sudeep Holla).
 
    * Fix for imx's default speed grade value (Anson Huang).
 
    * Minor cleanup of the s3c64xx driver (Nathan Chancellor).
 
    * CPU speed bin detection fix for sun50i (Ondrej Jirman).
 
  - Appoint Chanwoo Choi as the new devfreq maintainer.
 
  - Update the devfreq core:
 
    * Check NULL governor in available_governors_show sysfs to prevent
      showing wrong governor information and fix a race condition
      between devfreq_update_status() and trans_stat_show() (Leonard
      Crestez).
 
    * Add new 'interrupt-driven' flag for devfreq governors to allow
      interrupt-driven governors to prevent the devfreq core from
      polling devices for status (Dmitry Osipenko).
 
    * Improve an error message in devfreq_add_device() (Matthias
      Kaehlcke).
 
  - Update devfreq drivers:
 
    * tegra30 driver fixes and cleanups (Dmitry Osipenko).
 
    * Removal of unused property from dt-binding documentation for
      the exynos-bus driver (Kamil Konieczny).
 
    * exynos-ppmu cleanup and DT bindings update (Lukasz Luba, Marek
      Szyprowski).
 
  - Add new CPU IDs for CometLake Mobile and Desktop to the Intel RAPL
    power capping driver (Zhang Rui).
 
  - Allow device initialization in the generic power domains (genpd)
    framework to be more straightforward and clean it up (Ulf Hansson).
 
  - Add support for adjusting OPP voltages at run time to the OPP
    framework (Stephen Boyd).
 
  - Avoid freeing memory that has never been allocated in the
    hibernation core (Andy Whitcroft).
 
  - Clean up function headers in a header file and coding style in the
    wakeup IRQs handling code (Ulf Hansson, Xiaofei Tan).
 
  - Clean up the SmartReflex adaptive voltage scaling (AVS) driver for
    ARM (Ben Dooks, Geert Uytterhoeven).
 
  - Wrap power management documentation to fit in 80 columns (Bjorn
    Helgaas).
 
  - Add pm-graph utility entry to MAINTAINERS (Todd Brandt).
 
  - Update the cpupower utility:
 
    * Fix the handling of set and info subcommands (Abhishek Goel).
 
    * Fix build warnings (Nathan Chancellor).
 
    * Improve mperf_monitor handling (Janakarajan Natarajan).
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Merge tag 'pm-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These include cpuidle changes to use nanoseconds (instead of
  microseconds) as the unit of time and to simplify checks for disabled
  idle states in the idle loop, some cpuidle fixes and governor updates,
  assorted cpufreq updates (driver updates mostly and a few core fixes
  and cleanups), devfreq updates (dominated by the tegra30 driver
  changes), new CPU IDs for the RAPL power capping driver, relatively
  minor updates of the generic power domains (genpd) and operation
  performance points (OPP) frameworks, and assorted fixes and cleanups.

  There are also two maintainer information updates: Chanwoo Choi will
  be maintaining the devfreq subsystem going forward and Todd Brandt is
  going to maintain the pm-graph utility (created by him).

  Specifics:

   - Use nanoseconds (instead of microseconds) as the unit of time in
     the cpuidle core and simplify checks for disabled idle states in
     the idle loop (Rafael Wysocki)

   - Fix and clean up the teo cpuidle governor (Rafael Wysocki)

   - Fix the cpuidle registration error code path (Zhenzhong Duan)

   - Avoid excessive vmexits in the ACPI cpuidle driver (Yin Fengwei)

   - Extend the idle injection infrastructure to be able to measure the
     requested duration in nanoseconds and to allow an exit latency
     limit for idle states to be specified (Daniel Lezcano)

   - Fix cpufreq driver registration and clarify a comment in the
     cpufreq core (Viresh Kumar)

   - Add NULL checks to the show() and store() methods of sysfs
     attributes exposed by cpufreq (Kai Shen)

   - Update cpufreq drivers:
      * Fix for a plain int as pointer warning from sparse in
        intel_pstate (Jamal Shareef)
      * Fix for a hardcoded number of CPUs and stack bloat in the
        powernv driver (John Hubbard)
      * Updates to the ti-cpufreq driver and DT files to support new
        platforms and migrate bindings from opp-v1 to opp-v2 (Adam Ford,
        H. Nikolaus Schaller)
      * Merging of the arm_big_little and vexpress-spc drivers and
        related cleanup (Sudeep Holla)
      * Fix for imx's default speed grade value (Anson Huang)
      * Minor cleanup of the s3c64xx driver (Nathan Chancellor)
      * CPU speed bin detection fix for sun50i (Ondrej Jirman)

   - Appoint Chanwoo Choi as the new devfreq maintainer.

   - Update the devfreq core:
      * Check NULL governor in available_governors_show sysfs to prevent
        showing wrong governor information and fix a race condition
        between devfreq_update_status() and trans_stat_show() (Leonard
        Crestez)
      * Add new 'interrupt-driven' flag for devfreq governors to allow
        interrupt-driven governors to prevent the devfreq core from
        polling devices for status (Dmitry Osipenko)
      * Improve an error message in devfreq_add_device() (Matthias
        Kaehlcke)

   - Update devfreq drivers:
      * tegra30 driver fixes and cleanups (Dmitry Osipenko)
      * Removal of unused property from dt-binding documentation for the
        exynos-bus driver (Kamil Konieczny)
      * exynos-ppmu cleanup and DT bindings update (Lukasz Luba, Marek
        Szyprowski)

   - Add new CPU IDs for CometLake Mobile and Desktop to the Intel RAPL
     power capping driver (Zhang Rui)

   - Allow device initialization in the generic power domains (genpd)
     framework to be more straightforward and clean it up (Ulf Hansson)

   - Add support for adjusting OPP voltages at run time to the OPP
     framework (Stephen Boyd)

   - Avoid freeing memory that has never been allocated in the
     hibernation core (Andy Whitcroft)

   - Clean up function headers in a header file and coding style in the
     wakeup IRQs handling code (Ulf Hansson, Xiaofei Tan)

   - Clean up the SmartReflex adaptive voltage scaling (AVS) driver for
     ARM (Ben Dooks, Geert Uytterhoeven)

   - Wrap power management documentation to fit in 80 columns (Bjorn
     Helgaas)

   - Add pm-graph utility entry to MAINTAINERS (Todd Brandt)

   - Update the cpupower utility:
      * Fix the handling of set and info subcommands (Abhishek Goel)
      * Fix build warnings (Nathan Chancellor)
      * Improve mperf_monitor handling (Janakarajan Natarajan)"

* tag 'pm-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (83 commits)
  PM: Wrap documentation to fit in 80 columns
  cpuidle: Pass exit latency limit to cpuidle_use_deepest_state()
  cpuidle: Allow idle injection to apply exit latency limit
  cpuidle: Introduce cpuidle_driver_state_disabled() for driver quirks
  cpuidle: teo: Avoid code duplication in conditionals
  cpufreq: Register drivers only after CPU devices have been registered
  cpuidle: teo: Avoid using "early hits" incorrectly
  cpuidle: teo: Exclude cpuidle overhead from computations
  PM / Domains: Convert to dev_to_genpd_safe() in genpd_syscore_switch()
  mmc: tmio: Avoid boilerplate code in ->runtime_suspend()
  PM / Domains: Implement the ->start() callback for genpd
  PM / Domains: Introduce dev_pm_domain_start()
  ARM: OMAP2+: SmartReflex: add omap_sr_pdata definition
  PM / wakeirq: remove unnecessary parentheses
  power: avs: smartreflex: Remove superfluous cast in debugfs_create_file() call
  cpuidle: Use nanoseconds as the unit of time
  PM / OPP: Support adjusting OPP voltages at runtime
  PM / core: Clean up some function headers in power.h
  cpufreq: Add NULL checks to show() and store() methods of cpufreq
  cpufreq: intel_pstate: Fix plain int as pointer warning from sparse
  ...
2019-11-26 19:06:44 -08:00
Frederic Weisbecker
5720821ba1 cpufreq: Use vtime aware kcpustat accessors for user time
We can now safely read user and guest kcpustat fields on nohz_full CPUs.
Use the appropriate accessors.

Reported-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Link: https://lkml.kernel.org/r/20191121024430.19938-5-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-21 07:33:25 +01:00
Viresh Kumar
46770be0cf cpufreq: Register drivers only after CPU devices have been registered
The cpufreq core heavily depends on the availability of the struct
device for CPUs and if they aren't available at the time cpufreq driver
is registered, we will never succeed in making cpufreq work.

This happens due to following sequence of events:

- cpufreq_register_driver()
  - subsys_interface_register()
  - return 0; //successful registration of driver

... at a later point of time

- register_cpu();
  - device_register();
    - bus_probe_device();
      - sif->add_dev();
	- cpufreq_add_dev();
	  - get_cpu_device(); //FAILS
  - per_cpu(cpu_sys_devices, num) = &cpu->dev; //used by get_cpu_device()
  - return 0; //CPU registered successfully

Because the per-cpu variable cpu_sys_devices is set only after the CPU
device is regsitered, cpufreq will never be able to get it when
cpufreq_add_dev() is called.

This patch avoids this failure by making sure device structure of at
least CPU0 is available when the cpufreq driver is registered, else
return -EPROBE_DEFER.

Reported-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-11-14 09:37:14 +01:00
Ingo Molnar
6d5a763c30 Linux 5.4-rc7
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Merge tag 'v5.4-rc7' into sched/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-11 08:34:59 +01:00
Kai Shen
e6e8df0726 cpufreq: Add NULL checks to show() and store() methods of cpufreq
Add NULL checks to show() and store() in cpufreq.c to avoid attempts
to invoke a NULL callback.

Though some interfaces of cpufreq are set as read-only, users can
still get write permission using chmod which can lead to a kernel
crash, as follows:

chmod +w /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
echo 1 >  /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq

This bug was found in linux 4.19.

Signed-off-by: Kai Shen <shenkai8@huawei.com>
Reported-by: Feilong Lin <linfeilong@huawei.com>
Reviewed-by: Feilong Lin <linfeilong@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-11-08 11:49:15 +01:00
Viresh Kumar
737ffb27f2 cpufreq: Clarify the comment in cpufreq_set_policy()
One of the responsibility of the ->verify() callback is to make sure
that the policy's min frequency is <= max frequency as this isn't
guaranteed by the QoS framework which gave us those values.

Update the comment in cpufreq_set_policy() to clarify that.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Minor changes of the new comment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-11-04 11:44:26 +01:00
Frederic Weisbecker
49bb001e24 cpufreq: Use vtime aware kcpustat accessor to fetch CPUTIME_SYSTEM
Now that we have a vtime safe kcpustat accessor for CPUTIME_SYSTEM, use
it to start fixing frozen kcpustat values on nohz_full CPUs.

Reported-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpengli@tencent.com>
Link: https://lkml.kernel.org/r/20191016025700.31277-14-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-29 10:01:18 +01:00
Sudeep Holla
6941051d30 cpufreq: Cancel policy update work scheduled before freeing
Scheduled policy update work may end up racing with the freeing of the
policy and unregistering the driver.

One possible race is as below, where the cpufreq_driver is unregistered,
but the scheduled work gets executed at later stage when, cpufreq_driver
is NULL (i.e. after freeing the policy and driver).

Unable to handle kernel NULL pointer dereference at virtual address 0000001c
pgd = (ptrval)
[0000001c] *pgd=80000080204003, *pmd=00000000
Internal error: Oops: 206 [#1] SMP THUMB2
Modules linked in:
CPU: 0 PID: 34 Comm: kworker/0:1 Not tainted 5.4.0-rc3-00006-g67f5a8081a4b #86
Hardware name: ARM-Versatile Express
Workqueue: events handle_update
PC is at cpufreq_set_policy+0x58/0x228
LR is at dev_pm_qos_read_value+0x77/0xac
Control: 70c5387d  Table: 80203000  DAC: fffffffd
Process kworker/0:1 (pid: 34, stack limit = 0x(ptrval))
	(cpufreq_set_policy) from (refresh_frequency_limits.part.24+0x37/0x48)
	(refresh_frequency_limits.part.24) from (handle_update+0x2f/0x38)
	(handle_update) from (process_one_work+0x16d/0x3cc)
	(process_one_work) from (worker_thread+0xff/0x414)
	(worker_thread) from (kthread+0xff/0x100)
	(kthread) from (ret_from_fork+0x11/0x28)

Fixes: 67d874c3b2 ("cpufreq: Register notifiers with the PM QoS framework")
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
[ rjw: Cancel the work before dropping the QoS requests ]
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-10-22 18:07:30 +02:00
Rafael J. Wysocki
3000ce3c52 cpufreq: Use per-policy frequency QoS
Replace the CPU device PM QoS used for the management of min and max
frequency constraints in cpufreq (and its users) with per-policy
frequency QoS to avoid problems with cpufreq policies covering
more then one CPU.

Namely, a cpufreq driver is registered with the subsys interface
which calls cpufreq_add_dev() for each CPU, starting from CPU0, so
currently the PM QoS notifiers are added to the first CPU in the
policy (i.e. CPU0 in the majority of cases).

In turn, when the cpufreq driver is unregistered, the subsys interface
doing that calls cpufreq_remove_dev() for each CPU, starting from CPU0,
and the PM QoS notifiers are only removed when cpufreq_remove_dev() is
called for the last CPU in the policy, say CPUx, which as a rule is
not CPU0 if the policy covers more than one CPU.  Then, the PM QoS
notifiers cannot be removed, because CPUx does not have them, and
they are still there in the device PM QoS notifiers list of CPU0,
which prevents new PM QoS notifiers from being registered for CPU0
on the next attempt to register the cpufreq driver.

The same issue occurs when the first CPU in the policy goes offline
before unregistering the driver.

After this change it does not matter which CPU is the policy CPU at
the driver registration time and whether or not it is online all the
time, because the frequency QoS is per policy and not per CPU.

Fixes: 67d874c3b2 ("cpufreq: Register notifiers with the PM QoS framework")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Diagnosed-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/linux-pm/5ad2624194baa2f53acc1f1e627eb7684c577a19.1562210705.git.viresh.kumar@linaro.org/T/#md2d89e95906b8c91c15f582146173dce2e86e99f
Link: https://lore.kernel.org/linux-pm/20191017094612.6tbkwoq4harsjcqv@vireshk-i7/T/#m30d48cc23b9a80467fbaa16e30f90b3828a5a29b
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-10-21 02:05:21 +02:00
Rafael J. Wysocki
65650b3513 cpufreq: Avoid cpufreq_suspend() deadlock on system shutdown
It is incorrect to set the cpufreq syscore shutdown callback pointer
to cpufreq_suspend(), because that function cannot be run in the
syscore stage of system shutdown for two reasons: (a) it may attempt
to carry out actions depending on devices that have already been shut
down at that point and (b) the RCU synchronization carried out by it
may not be able to make progress then.

The latter issue has been present since commit 45975c7d21 ("rcu:
Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds"),
but the former one has been there since commit 90de2a4aa9 ("cpufreq:
suspend cpufreq governors on shutdown") regardless.

Fix that by dropping cpufreq_syscore_ops altogether and making
device_shutdown() call cpufreq_suspend() directly before shutting
down devices, which is along the lines of what system-wide power
management does.

Fixes: 45975c7d21 ("rcu: Define RCU-sched API in terms of RCU for Tree RCU PREEMPT builds")
Fixes: 90de2a4aa9 ("cpufreq: suspend cpufreq governors on shutdown")
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.0+ <stable@vger.kernel.org> # 4.0+
2019-10-10 11:11:17 +02:00
Rafael J. Wysocki
beb4e08e21 Merge branch 'pm-cpufreq-qos'
* pm-cpufreq-qos:
  Documentation: cpufreq: Update policy notifier documentation
  cpufreq: Remove CPUFREQ_ADJUST and CPUFREQ_NOTIFY policy notifier events
  ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier
  video: pxafb: Remove cpufreq policy notifier
  video: sa1100fb: Remove cpufreq policy notifier
  arch_topology: Use CPUFREQ_CREATE_POLICY instead of CPUFREQ_NOTIFY
  cpufreq: powerpc_cbe: Switch to QoS requests for freq limits
  cpufreq: powerpc: macintosh: Switch to QoS requests for freq limits
  thermal: cpu_cooling: Switch to QoS requests for freq limits
  cpufreq: Add policy create/remove notifiers back
2019-09-05 09:01:26 +02:00
Viresh Kumar
df0eea4488 cpufreq: Remove CPUFREQ_ADJUST and CPUFREQ_NOTIFY policy notifier events
No driver makes reference to these events now, remove them and the code
related to them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-09-02 22:44:04 +02:00
Florian Fainelli
e9a7cc1d97 cpufreq: Print driver name if cpufreq_suspend() fails
Instead of printing the policy, which is incidentally a kernel pointer,
so with limited interest, print the cpufreq driver name that failed to
be suspend, which is more useful for debugging.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-22 09:27:25 +02:00
Colin Ian King
62c23a89fd cpufreq: remove redundant assignment to ret
Variable ret is initialized to a value that is never read and it is
re-assigned later. The initialization is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-21 00:28:30 +02:00
Viresh Kumar
6a1490367c cpufreq: Add policy create/remove notifiers back
This effectively reverts some changes made by commit f9f41e3ef9
("cpufreq: Remove policy create/remove notifiers").

We have a new use case for policy create/remove notifiers (for
allocating/freeing QoS requests per policy), so add them back.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-10 14:05:48 +02:00
Viresh Kumar
e61a41256e cpufreq: dev_pm_qos_update_request() can return 1 on success
dev_pm_qos_update_request() can return 1 on success, so don't treat
it as an error.

Fixes: 18c49926c4 ("cpufreq: Add QoS requests for userspace constraints")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-10 13:39:47 +02:00
Rafael J. Wysocki
918e162e6a Merge branch 'pm-cpufreq'
* pm-cpufreq:
  cpufreq: Make cpufreq_generic_init() return void
  cpufreq: imx-cpufreq-dt: Add i.MX8MN support
  cpufreq: Add QoS requests for userspace constraints
  cpufreq: intel_pstate: Reuse refresh_frequency_limits()
  cpufreq: Register notifiers with the PM QoS framework
  PM / QoS: Add support for MIN/MAX frequency constraints
  PM / QOS: Pass request type to dev_pm_qos_read_value()
  PM / QOS: Rename __dev_pm_qos_read_value() and dev_pm_qos_raw_read_value()
  PM / QOS: Pass request type to dev_pm_qos_{add|remove}_notifier()
2019-07-18 09:49:30 +02:00
Viresh Kumar
c4dcc8a162 cpufreq: Make cpufreq_generic_init() return void
It always returns 0 (success) and its return type should really be void.

Over that, many drivers have added error handling code based on its
return value, which is not required at all.

Change its return type to void and update all the callers.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-16 10:20:11 +02:00
Viresh Kumar
18c49926c4 cpufreq: Add QoS requests for userspace constraints
This implements QoS requests to manage userspace configuration of min
and max frequency.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: syzbot <syzbot+de771ae9390dffed7266@syzkaller.appspotmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-08 23:56:39 +02:00
Viresh Kumar
c57b25bdf7 cpufreq: intel_pstate: Reuse refresh_frequency_limits()
The implementation of intel_pstate_update_max_freq() is quite similar to
refresh_frequency_limits(), lets reuse it.

Finding minimum of policy->user_policy.max and policy->cpuinfo.max_freq
in intel_pstate_update_max_freq() is redundant as cpufreq_set_policy()
will call the ->verify() callback of intel-pstate driver, which will do
this comparison anyway and so dropping it from
intel_pstate_update_max_freq() doesn't harm.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-08 23:56:39 +02:00
Viresh Kumar
67d874c3b2 cpufreq: Register notifiers with the PM QoS framework
Register notifiers for min/max frequency constraints with the PM QoS
framework. The constraints are also taken into consideration in
cpufreq_set_policy().

This also relocates cpufreq_policy_put_kobj() as it is required to be
called from cpufreq_policy_alloc() now.

refresh_frequency_limits() is updated to avoid calling
cpufreq_set_policy() for inactive policies and handle_update() is
updated to have proper locking in place.

No constraints are added until now though.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-07-08 23:56:13 +02:00
Rafael J. Wysocki
586a07dca8 Merge branch 'pm-cpufreq'
* pm-cpufreq:
  cpufreq: Avoid calling cpufreq_verify_current_freq() from handle_update()
  cpufreq: Consolidate cpufreq_update_current_freq() and __cpufreq_get()
  cpufreq: Don't skip frequency validation for has_target() drivers
  cpufreq: Use has_target() instead of !setpolicy
  cpufreq: Remove redundant !setpolicy check
  cpufreq: Move the IS_ENABLED(CPU_THERMAL) macro into a stub
  cpufreq: s5pv210: Don't flood kernel log after cpufreq change
  cpufreq: pcc-cpufreq: Fail initialization if driver cannot be registered
  cpufreq: add driver for Raspberry Pi
  cpufreq: Switch imx7d to imx-cpufreq-dt for speed grading
  cpufreq: imx-cpufreq-dt: Remove global platform match list
  cpufreq: brcmstb-avs-cpufreq: Fix types for voltage/frequency
  cpufreq: brcmstb-avs-cpufreq: Fix initial command check
  cpufreq: armada-37xx: Remove set but not used variable 'freq'
  cpufreq: imx-cpufreq-dt: Fix no OPPs available on unfused parts
  dt-bindings: imx-cpufreq-dt: Document opp-supported-hw usage
  cpufreq: Add imx-cpufreq-dt driver
2019-07-08 11:00:02 +02:00
Viresh Kumar
70a59fde6e cpufreq: Avoid calling cpufreq_verify_current_freq() from handle_update()
On some occasions cpufreq_verify_current_freq() schedules a work whose
callback is handle_update(), which further calls cpufreq_update_policy()
which may end up calling cpufreq_verify_current_freq() again.

On the other hand, when cpufreq_update_policy() is called from
handle_update(), the pointer to the cpufreq policy is already
available, but cpufreq_cpu_acquire() is still called to get it in
cpufreq_update_policy(), which should be avoided as well.

To fix these issues, create a new helper, refresh_frequency_limits(),
and make both handle_update() call it cpufreq_update_policy().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Rename reeval_frequency_limits() as refresh_frequency_limits() ]
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-28 11:24:56 +02:00
Viresh Kumar
5980752e6e cpufreq: Consolidate cpufreq_update_current_freq() and __cpufreq_get()
Their implementations are quite similar, so modify
cpufreq_update_current_freq() somewhat and call it from
__cpufreq_get().

Also rename cpufreq_update_current_freq() to
cpufreq_verify_current_freq(), as that's what it is doing.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-28 11:17:12 +02:00
Viresh Kumar
9801522840 cpufreq: Don't skip frequency validation for has_target() drivers
CPUFREQ_CONST_LOOPS was introduced in a very old commit from pre-2.6
kernel release by commit 6a4a93f9c0d5 ("[CPUFREQ] Fix 'out of sync'
issue").

Basically, that commit does two things:

 - It adds the frequency verification code (which is quite similar to
   what we have today as well).

 - And it sets the CPUFREQ_CONST_LOOPS flag only for setpolicy drivers,
   rightly so based on the code we had then. The idea was to avoid
   frequency validation for setpolicy drivers as the cpufreq core doesn't
   know what frequency the hardware is running at and so no point in
   doing frequency verification.

The problem happened when we started to use the same CPUFREQ_CONST_LOOPS
flag for constant loops-per-jiffy thing as well and many has_target()
drivers started using the same flag and unknowingly skipped the
verification of frequency. There is no logical reason behind skipping
frequency validation because of the presence of CPUFREQ_CONST_LOOPS
flag otherwise.

Fix this issue by skipping frequency validation only for setpolicy
drivers and always doing it for has_target() drivers irrespective of
the presence or absence of CPUFREQ_CONST_LOOPS flag.

cpufreq_notify_transition() is only called for has_target() type driver
and not for set_policy type, and the check is simply redundant. Remove
it as well.

Also remove () around freq comparison statement as they aren't required
and checkpatch also warns for them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-28 10:16:14 +02:00
Viresh Kumar
5ddc6d4e30 cpufreq: Use has_target() instead of !setpolicy
For code consistency, use has_target() instead of !setpolicy everywhere,
as it is already done at several places. Maybe we should also use
"!has_target()" instead of "cpufreq_driver->setpolicy" where we need to
check if the driver supports setpolicy, so to use only one expression
for this kind of differentiation.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-26 11:41:04 +02:00
Viresh Kumar
407d0fff22 cpufreq: Remove redundant !setpolicy check
cpufreq_start_governor() is only called for !setpolicy case, checking it
again is not required.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-26 11:36:55 +02:00
Daniel Lezcano
bcc6156999 cpufreq: Move the IS_ENABLED(CPU_THERMAL) macro into a stub
cpufreq_online() and cpufreq_offline() [un]register the driver as
a cooling device. This is done if the driver is flagged as a cooling
device in addition with an IS_ENABLED() check to compile out the branching
code.

Group this test in a stub function added in the cpufreq header instead
of having the IS_ENABLED() in the code.

Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-26 10:59:57 +02:00
Thomas Gleixner
d2912cb15b treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00
Linus Torvalds
bfbfbf7368 More power management updates for 5.2-rc1
- Fix recent regression causing kernels built with CONFIG_PM
    unset to crash on systems that support the Performance and
    Energy Bias Hint (EPB) by avoiding to compile the EPB-related
    code depending on CONFIG_PM when it is unset (Rafael Wysocki).
 
  - Clean up the transition notifier invocation code in the cpufreq
    core and change some users of cpufreq transition notifiers
    accordingly (Viresh Kumar).
 
  - Change MAINTAINERS to cover the schedutil governor as part of
    cpufreq (Viresh Kumar).
 
  - Simplify cpufreq_init_policy() to avoid redundant computations
    (Yue Hu).
 
  - Add explanatory comment to the cpufreq core (Rafael Wysocki).
 
  - Introduce a new flag, GENPD_FLAG_RPM_ALWAYS_ON, to the generic
    power domains (genpd) framework along with the first user of it
    (Leonard Crestez).
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Merge tag 'pm-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power management updates from Rafael Wysocki:
 "These fix a recent regression causing kernels built with CONFIG_PM
  unset to crash on systems that support the Performance and Energy Bias
  Hint (EPB), clean up the cpufreq core and some users of transition
  notifiers and introduce a new power domain flag into the generic power
  domains framework (genpd).

  Specifics:

   - Fix recent regression causing kernels built with CONFIG_PM unset to
     crash on systems that support the Performance and Energy Bias Hint
     (EPB) by avoiding to compile the EPB-related code depending on
     CONFIG_PM when it is unset (Rafael Wysocki).

   - Clean up the transition notifier invocation code in the cpufreq
     core and change some users of cpufreq transition notifiers
     accordingly (Viresh Kumar).

   - Change MAINTAINERS to cover the schedutil governor as part of
     cpufreq (Viresh Kumar).

   - Simplify cpufreq_init_policy() to avoid redundant computations (Yue
     Hu).

   - Add explanatory comment to the cpufreq core (Rafael Wysocki).

   - Introduce a new flag, GENPD_FLAG_RPM_ALWAYS_ON, to the generic
     power domains (genpd) framework along with the first user of it
     (Leonard Crestez)"

* tag 'pm-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  soc: imx: gpc: Use GENPD_FLAG_RPM_ALWAYS_ON for ERR009619
  PM / Domains: Add GENPD_FLAG_RPM_ALWAYS_ON flag
  cpufreq: Update MAINTAINERS to include schedutil governor
  cpufreq: Don't find governor for setpolicy drivers in cpufreq_init_policy()
  cpufreq: Explain the kobject_put() in cpufreq_policy_alloc()
  cpufreq: Call transition notifier only once for each policy
  x86: intel_epb: Take CONFIG_PM into account
2019-05-15 08:46:44 -07:00
Yue Hu
ab05d97a37 cpufreq: Don't find governor for setpolicy drivers in cpufreq_init_policy()
In cpufreq_init_policy() we will check if there's last_governor for target
and setpolicy type. However last_governor is set only if has_target() is
true in cpufreq_offline(). That means find last_governor for setpolicy
type is pointless. Also new_policy.governor will not be used if ->setpolicy
callback is set in cpufreq_set_policy().

Moreover, there's duplicate ->setpolicy check in using default policy path.
Let's add a new helper function to avoid it. Also update comments.

Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-05-13 10:46:24 +02:00
Rafael J. Wysocki
2acb9bdae9 cpufreq: Explain the kobject_put() in cpufreq_policy_alloc()
It may not be particularly clear why the kobject_put() after
failing kobject_init_and_add() in cpufreq_policy_alloc() is not
redundant, so add a comment to explain that.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-05-13 10:43:53 +02:00
Viresh Kumar
df24014abe cpufreq: Call transition notifier only once for each policy
Currently, the notifiers are called once for each CPU of the policy->cpus
cpumask. It would be more optimal if the notifier can be called only
once and all the relevant information be provided to it. Out of the 23
drivers that register for the transition notifiers today, only 4 of them
do per-cpu updates and the callback for the rest can be called only once
for the policy without any impact.

This would also avoid multiple function calls to the notifier callbacks
and reduce multiple iterations of notifier core's code (which does
locking as well).

This patch adds pointer to the cpufreq policy to the struct
cpufreq_freqs, so the notifier callback has all the information
available to it with a single call. The five drivers which perform
per-cpu updates are updated to use the cpufreq policy. The freqs->cpu
field is redundant now and is removed.

Acked-by: David S. Miller <davem@davemloft.net> (sparc)
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-05-10 12:20:36 +02:00
Linus Torvalds
0968621917 Printk changes for 5.2
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Merge tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Allow state reset of printk_once() calls.

 - Prevent crashes when dereferencing invalid pointers in vsprintf().
   Only the first byte is checked for simplicity.

 - Make vsprintf warnings consistent and inlined.

 - Treewide conversion of obsolete %pf, %pF to %ps, %pF printf
   modifiers.

 - Some clean up of vsprintf and test_printf code.

* tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  lib/vsprintf: Make function pointer_string static
  vsprintf: Limit the length of inlined error messages
  vsprintf: Avoid confusion between invalid address and value
  vsprintf: Prevent crash when dereferencing invalid pointers
  vsprintf: Consolidate handling of unknown pointer specifiers
  vsprintf: Factor out %pO handler as kobject_string()
  vsprintf: Factor out %pV handler as va_format()
  vsprintf: Factor out %p[iI] handler as ip_addr_string()
  vsprintf: Do not check address of well-known strings
  vsprintf: Consistent %pK handling for kptr_restrict == 0
  vsprintf: Shuffle restricted_pointer()
  printk: Tie printk_once / printk_deferred_once into .data.once for reset
  treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively
  lib/test_printf: Switch to bitmap_zalloc()
2019-05-07 09:18:12 -07:00
Viresh Kumar
4ebe36c94a cpufreq: Fix kobject memleak
Currently the error return path from kobject_init_and_add() is not
followed by a call to kobject_put() - which means we are leaking the
kobject.

Fix it by adding a call to kobject_put() in the error path of
kobject_init_and_add().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Tobin C. Harding <tobin@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-30 10:54:23 +02:00
Yue Hu
4db7c34cb4 cpufreq: Move ->get callback check outside of __cpufreq_get()
Currenly, __cpufreq_get() called by show_cpuinfo_cur_freq() will check
->get callback. That is needless since cpuinfo_cur_freq attribute will
not be created if ->get is not set. So let's drop it in __cpufreq_get().
Also keep this check in cpufreq_get().

Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-23 10:58:43 +02:00
Yue Hu
b23aa311fa cpufreq: Remove needless bios_limit check in show_bios_limit()
Initially, bios_limit attribute will be created if driver->bios_limit
is set in cpufreq_add_dev_interface(). So remove the redundant check
for latter show operation.

Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-16 23:10:42 +02:00
Sakari Ailus
d75f773c86 treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively
%pF and %pf are functionally equivalent to %pS and %ps conversion
specifiers. The former are deprecated, therefore switch the current users
to use the preferred variant.

The changes have been produced by the following command:

	git grep -l '%p[fF]' | grep -v '^\(tools\|Documentation\)/' | \
	while read i; do perl -i -pe 's/%pf/%ps/g; s/%pF/%pS/g;' $i; done

And verifying the result.

Link: http://lkml.kernel.org/r/20190325193229.23390-1-sakari.ailus@linux.intel.com
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: sparclinux@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: xen-devel@lists.xenproject.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Cc: linux-mmc@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: linux-pci@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: linux-btrfs@vger.kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: linux-mm@kvack.org
Cc: ceph-devel@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: David Sterba <dsterba@suse.com> (for btrfs)
Acked-by: Mike Rapoport <rppt@linux.ibm.com> (for mm/memblock.c)
Acked-by: Bjorn Helgaas <bhelgaas@google.com> (for drivers/pci)
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-04-09 14:19:06 +02:00
Yue Hu
89f98d7e5f cpufreq: Remove cpufreq_driver check in cpufreq_boost_supported()
Currently there are three calling paths for cpufreq_boost_supported() in
all as below, we can see the cpufreq_driver null check is needless since
it is already checked before.

<path1>
  cpufreq_enable_boost_support()
    |-> if (!cpufreq_driver)
    |-> cpufreq_boost_supported()

<path2>
  cpufreq_register_driver()
    |-> if (!driver_data ...
    |-> cpufreq_driver = driver_data
    |-> cpufreq_boost_supported()
    |-> remove_boost_sysfs_file()
          |-> cpufreq_boost_supported()

<path3>
  cpufreq_unregister_driver()
    |-> if (!cpufreq_driver ...
    |-> remove_boost_sysfs_file()
          |-> cpufreq_boost_supported()

Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-09 09:57:16 +02:00
Rafael J. Wysocki
9083e49861 cpufreq: intel_pstate: Update max frequency on global turbo changes
While the cpuinfo.max_freq value doesn't really matter for
intel_pstate in the active mode, in the passive mode it is used by
governors as the maximum physical frequency of the CPU and the
results of governor computations generally depend on it.  Also it
is made available to user space via sysfs and it should match the
current HW configuration.

For this reason, make intel_pstate update cpuinfo.max_freq for all
CPUs if it detects a global change of turbo frequency settings from
"disable" to "enable" or the other way associated with a _PPC change
notification from the platform firmware.

Note that policy_is_inactive(),  cpufreq_cpu_acquire(),
cpufreq_cpu_release(), and cpufreq_set_policy() need to be made
available to it for this purpose.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759
Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-08 11:26:09 +02:00
Rafael J. Wysocki
540a375822 cpufreq: Add cpufreq_cpu_acquire() and cpufreq_cpu_release()
It sometimes is necessary to find a cpufreq policy for a given CPU
and acquire its rwsem (for writing) immediately after that, so
introduce cpufreq_cpu_acquire() as a helper for that and the
complementary cpufreq_cpu_release().

Make cpufreq_update_policy() use the new functions.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-01 23:43:05 +02:00
Rafael J. Wysocki
5a25e3f7cc cpufreq: intel_pstate: Driver-specific handling of _PPC updates
In some cases, the platform firmware disables or enables turbo
frequencies for all CPUs globally before triggering a _PPC change
notification for one of them.  Obviously, that global change affects
all CPUs, not just the notified one, and it needs to be acted upon by
cpufreq.

The intel_pstate driver is able to detect such global changes of
the settings, but it also needs to update policy limits for all
CPUs if that happens, in particular if turbo frequencies are
enabled globally - to allow them to be used.

For this reason, introduce a new cpufreq driver callback to be
invoked on _PPC notifications, if present, instead of simply
calling cpufreq_update_policy() for the notified CPU and make
intel_pstate use it to trigger policy updates for all CPUs
in the system if global settings change.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759
Reported-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-04-01 23:43:05 +02:00
Rafael J. Wysocki
5d094fea14 cpufreq: Improve kerneldoc comments for cpufreq_cpu_get/put()
Fix the formatting of the cpufreq_cpu_get() and cpufreq_cpu_put()
kerneldoc comments and rework them to be somewhat easier to follow.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-03-07 10:55:29 +01:00
Rafael J. Wysocki
167a38dcd5 cpufreq: Pass updated policy to driver ->setpolicy() callback
The invocation of the ->setpolicy() cpufreq driver callback should
be equivalent to calling cpufreq_governor_limits(policy) for drivers
with internal governors, but in fact it isn't so, because the
temporary new_policy object is passed to it instead of the updated
policy.

That is a bit confusing, so make cpufreq_set_policy() pass the
updated policy to the driver ->setpolicy() callback.

No intentional changes of behavior.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-20 10:18:37 +01:00
Rafael J. Wysocki
2bb4059e07 cpufreq: Fix two debug messages in cpufreq_set_policy()
Remove the redundant "cpufreq:" prefix from two debug messages in
cpufreq_set_policy().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-20 10:18:37 +01:00
Rafael J. Wysocki
348a2ec5f5 cpufreq: Reorder and simplify cpufreq_update_policy()
In cpufreq_update_policy(), instead of updating new_policy.cur
separately, which is kind of confusing, because cpufreq_set_policy()
doesn't take that value into account directly anyway, make the copy
of the existing policy after calling cpufreq_update_current_freq().

No intentional changes of behavior.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-20 10:18:37 +01:00
Rafael J. Wysocki
a0dbb819b8 cpufreq: Add kerneldoc comments for two core functions
Add kerneldoc comments describing cpufreq_set_policy() and
cpufreq_update_policy() as they have not been properly documented
so far and they really need to be documented.

While at it, fix white space around the cpufreq_set_policy() header.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2019-02-20 10:18:37 +01:00
Viresh Kumar
a9a22b570b cpufreq: Replace double NOT (!!) with single NOT (!)
Double NOT (!!) operation is normally done to convert a non-zero value
to 1 and keep zero as is, but that isn't the requirement in this case.
All we wanted was to make sure that only one of the two routines isn't
set, i.e. either both function pointers are set or both are unset.

This can be done with a single NOT (!) operation as well.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-14 12:06:38 +01:00
Viresh Kumar
91a12e91dc cpufreq: Allow light-weight tear down and bring up of CPUs
The cpufreq core doesn't remove the cpufreq policy anymore on CPU
offline operation, rather that happens when the CPU device gets
unregistered from the kernel. This allows faster recovery when the CPU
comes back online. This is also very useful during system wide
suspend/resume where we offline all non-boot CPUs during suspend and
then bring them back on resume.

This commit takes the same idea a step ahead to allow drivers to do
light weight tear-down and bring-up during CPU offline and online
operations.

A new set of callbacks is introduced, online/offline(). online() gets
called when the first CPU of an inactive policy is brought up and
offline() gets called when all the CPUs of a policy are offlined.

The existing init/exit() callback get called on policy
creation/destruction. They also get called instead of online/offline()
callbacks if the online/offline() callbacks aren't provided.

This also moves around some code to get executed only for the new-policy
case going forward.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-12 23:47:42 +01:00
Amit Kucheria
5c238a8b59 cpufreq: Auto-register the driver as a thermal cooling device if asked
All cpufreq drivers do similar things to register as a cooling device.
Provide a cpufreq driver flag so drivers can just ask the cpufreq core
to register the cooling device on their behalf. This allows us to get
rid of duplicated code in the drivers.

In order to allow this, we add a struct thermal_cooling_device pointer
to struct cpufreq_policy so that drivers don't need to store it in a
private data structure.

Suggested-by: Stephen Boyd <swboyd@chromium.org>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-30 23:02:26 +01:00
Viresh Kumar
625c85a62c cpufreq: Use struct kobj_attribute instead of struct global_attr
The cpufreq_global_kobject is created using kobject_create_and_add()
helper, which assigns the kobj_type as dynamic_kobj_ktype and show/store
routines are set to kobj_attr_show() and kobj_attr_store().

These routines pass struct kobj_attribute as an argument to the
show/store callbacks. But all the cpufreq files created using the
cpufreq_global_kobject expect the argument to be of type struct
attribute. Things work fine currently as no one accesses the "attr"
argument. We may not see issues even if the argument is used, as struct
kobj_attribute has struct attribute as its first element and so they
will both get same address.

But this is logically incorrect and we should rather use struct
kobj_attribute instead of struct global_attr in the cpufreq core and
drivers and the show/store callbacks should take struct kobj_attribute
as argument instead.

This bug is caught using CFI CLANG builds in android kernel which
catches mismatch in function prototypes for such callbacks.

Reported-by: Donghee Han <dh.han@samsung.com>
Reported-by: Sangkyu Kim <skwith.kim@samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-29 11:44:30 +01:00
Viresh Kumar
21469df467 cpufreq: Don't update new_policy on failures
The local variable "new_policy" hasn't been used in the error path of
cpufreq_online() since commit f9f41e3ef9 (cpufreq: Remove policy
create/remove notifiers).  Don't update it in that error path.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-15 22:57:04 +01:00
Rafael J. Wysocki
343e60e52a Merge branches 'pm-cpuidle', 'pm-cpufreq' and 'pm-sleep'
* pm-cpuidle:
  doc: trace: fix reference to cpuidle documentation file
  cpuidle / Documentation: Update cpuidle MAINTAINERS entry

* pm-cpufreq:
  cpufreq: scmi: Fix frequency invariance in slow path
  cpufreq: check if policy is inactive early in __cpufreq_get()
  cpufreq: scpi/scmi: Fix freeing of dynamic OPPs
  cpufreq / Documentation: Update cpufreq MAINTAINERS entry

* pm-sleep:
  PM: sleep: call devfreq suspend/resume
2019-01-11 10:09:51 +01:00
Sudeep Holla
2f66196208 cpufreq: check if policy is inactive early in __cpufreq_get()
cpuinfo_cur_freq gets current CPU frequency as detected by hardware
while scaling_cur_freq last known CPU frequency. Some platforms may not
allow checking the CPU frequency of an offline CPU or the associated
resources may have been released via cpufreq_exit when the CPU gets
offlined, in which case the policy would have been invalidated already.
If we attempt to get current frequency from the hardware, it may result
in hang or crash.

For example on Juno, I see:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188
[0000000000000188] pgd=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 5 PID: 4202 Comm: cat Not tainted 4.20.0-08251-ga0f2c0318a15-dirty #87
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform
pstate: 40000005 (nZcv daif -PAN -UAO)
pc : scmi_cpufreq_get_rate+0x34/0xb0
lr : scmi_cpufreq_get_rate+0x34/0xb0
Call trace:
 scmi_cpufreq_get_rate+0x34/0xb0
 __cpufreq_get+0x34/0xc0
 show_cpuinfo_cur_freq+0x24/0x78
 show+0x40/0x60
 sysfs_kf_seq_show+0xc0/0x148
 kernfs_seq_show+0x44/0x50
 seq_read+0xd4/0x480
 kernfs_fop_read+0x15c/0x208
 __vfs_read+0x60/0x188
 vfs_read+0x94/0x150
 ksys_read+0x6c/0xd8
 __arm64_sys_read+0x24/0x30
 el0_svc_common+0x78/0x100
 el0_svc_handler+0x38/0x78
 el0_svc+0x8/0xc
---[ end trace 3d1024e58f77f6b2 ]---

So fix the issue by checking if the policy is invalid early in
__cpufreq_get before attempting to get the current frequency.

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-01-08 10:49:50 +01:00
Quentin Perret
531b5c9f5c sched/topology: Make Energy Aware Scheduling depend on schedutil
Energy Aware Scheduling (EAS) is designed with the assumption that
frequencies of CPUs follow their utilization value. When using a CPUFreq
governor other than schedutil, the chances of this assumption being true
are small, if any. When schedutil is being used, EAS' predictions are at
least consistent with the frequency requests. Although those requests
have no guarantees to be honored by the hardware, they should at least
guide DVFS in the right direction and provide some hope in regards to the
EAS model being accurate.

To make sure EAS is only used in a sane configuration, create a strong
dependency on schedutil being used. Since having sugov compiled-in does
not provide that guarantee, make CPUFreq call a scheduler function on
governor changes hence letting it rebuild the scheduling domains, check
the governors of the online CPUs, and enable/disable EAS accordingly.

Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adharmap@codeaurora.org
Cc: chris.redpath@arm.com
Cc: currojerez@riseup.net
Cc: dietmar.eggemann@arm.com
Cc: edubezval@gmail.com
Cc: gregkh@linuxfoundation.org
Cc: javi.merino@kernel.org
Cc: joel@joelfernandes.org
Cc: juri.lelli@redhat.com
Cc: morten.rasmussen@arm.com
Cc: patrick.bellasi@arm.com
Cc: pkondeti@codeaurora.org
Cc: skannan@codeaurora.org
Cc: smuckle@google.com
Cc: srinivas.pandruvada@linux.intel.com
Cc: thara.gopinath@linaro.org
Cc: tkjos@google.com
Cc: valentin.schneider@arm.com
Cc: vincent.guittot@linaro.org
Cc: viresh.kumar@linaro.org
Link: https://lkml.kernel.org/r/20181203095628.11858-9-quentin.perret@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-12-11 15:17:00 +01:00
Igor Stoppa
0e7ea2f3b0 cpufreq: remove unnecessary unlikely()
WARN_ON() already contains an unlikely(), so it's not necessary to wrap it
into another.

Signed-off-by: Igor Stoppa <igor.stoppa@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-09-10 12:04:42 +02:00
Waiman Long
9b3d9bb3e4 cpufreq: Fix a circular lock dependency problem
With lockdep turned on, the following circular lock dependency problem
was reported:

[   57.470040] ======================================================
[   57.502900] WARNING: possible circular locking dependency detected
[   57.535208] 4.18.0-0.rc3.1.el8+7.x86_64+debug #1 Tainted: G
[   57.577761] ------------------------------------------------------
[   57.609714] tuned/1505 is trying to acquire lock:
[   57.633808] 00000000559deec5 (cpu_hotplug_lock.rw_sem){++++}, at: store+0x27/0x120
[   57.672880]
[   57.672880] but task is already holding lock:
[   57.702184] 000000002136ca64 (kn->count#118){++++}, at: kernfs_fop_write+0x1d0/0x410
[   57.742176]
[   57.742176] which lock already depends on the new lock.
[   57.742176]
[   57.785220]
[   57.785220] the existing dependency chain (in reverse order) is:
    :
[   58.932512] other info that might help us debug this:
[   58.932512]
[   58.973344] Chain exists of:
[   58.973344]   cpu_hotplug_lock.rw_sem --> subsys mutex#5 --> kn->count#118
[   58.973344]
[   59.030795]  Possible unsafe locking scenario:
[   59.030795]
[   59.061248]        CPU0                    CPU1
[   59.085377]        ----                    ----
[   59.108160]   lock(kn->count#118);
[   59.124935]                                lock(subsys mutex#5);
[   59.156330]                                lock(kn->count#118);
[   59.186088]   lock(cpu_hotplug_lock.rw_sem);
[   59.208541]
[   59.208541]  *** DEADLOCK ***

In the cpufreq_register_driver() function, the lock sequence is:

  cpus_read_lock --> kn->count

For the cpufreq sysfs store method, the lock sequence is:

  kn->count --> cpus_read_lock

These sequences are actually safe as they are taking a share lock on
cpu_hotplug_lock. However, the current lockdep code doesn't check for
share locking when detecting circular lock dependency.  Fixing that
could be a substantial effort.

Instead, we can work around this problem by using cpus_read_trylock()
in the store method which is much simpler. The chance of not getting
the read lock is very small. If that happens, the userspace application
that writes the sysfs file will get an error.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-26 10:37:36 +02:00
Ruchi Kandoi
601b218568 cpufreq: trace frequency limits change
systrace used for tracing for Android systems has carried a patch for
many years in the Android tree that traces when the cpufreq limits
change.  With the help of this information, systrace can know when the
policy limits change and can visually display the data. Lets add
upstream support for the same.

Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-26 10:17:47 +02:00
Sebastian Andrzej Siewior
cc85de361d cpufreq: Use static SRCU initializer
Use the static SRCU initializer for `cpufreq_transition_notifier_list'.
This avoids the init_cpufreq_transition_notifier_list() initcall. Its
only purpose is to initialize the SRCU notifier once during boot and set
another variable which is used as an indicator whether the init was
perfromed before cpufreq_register_notifier() was used.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-30 11:16:59 +02:00
Tao Wang
c7d1f119c4 cpufreq: Fix new policy initialization during limits updates via sysfs
If the policy limits are updated via cpufreq_update_policy() and
subsequently via sysfs, the limits stored in user_policy may be
set incorrectly.

For example, if both min and max are set via sysfs to the maximum
available frequency, user_policy.min and user_policy.max will also
be the maximum.  If a policy notifier triggered by
cpufreq_update_policy() lowers both the min and the max at this
point, that change is not reflected by the user_policy limits, so
if the max is updated again via sysfs to the same lower value,
then user_policy.max will be lower than user_policy.min which
shouldn't happen.  In particular, if one of the policy CPUs is
then taken offline and back online, cpufreq_set_policy() will
fail for it due to a failing limits check.

To prevent that from happening, initialize the min and max fields
of the new_policy object to the ones stored in user_policy that
were previously set via sysfs.

Signed-off-by: Kevin Wangtao <kevin.wangtao@hisilicon.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject & changelog ]
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-30 10:11:34 +02:00
Viresh Kumar
20b5324d83 cpufreq: optimize cpufreq_notify_transition()
cpufreq_notify_transition() calls __cpufreq_notify_transition() for each
CPU of a policy. There is a lot of code in __cpufreq_notify_transition()
though which isn't required to be executed for each CPU, like checking
about disabled cpufreq or irqs, adjusting jiffies, updating cpufreq
stats and some debug print messages.

This commit merges __cpufreq_notify_transition() into
cpufreq_notify_transition() and modifies cpufreq_notify_transition() to
execute minimum amount of code for each CPU.

Also fix the kerneldoc for cpufreq_notify_transition() while at it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-13 11:09:00 +02:00
Viresh Kumar
92c99d159c cpufreq: Don't validate cpufreq table from cpufreq_generic_init()
The cpufreq table is already validated by the cpufreq core and none of
the users of cpufreq_generic_init() have any dependency on it to
validate the table as well.

Don't validate the cpufreq table anymore from cpufreq_generic_init().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-03-20 12:07:51 +01:00
Viresh Kumar
d417e0691a cpufreq: Validate frequency table in the core
By design, cpufreq drivers are responsible for calling
cpufreq_frequency_table_cpuinfo() from their ->init()
callbacks to validate the frequency table.

However, if a cpufreq driver is buggy and fails to do so properly, it
lead to unexpected behavior of the driver or the cpufreq core at a
later point in time.  It would be better if the core could
validate the frequency table during driver initialization.

To that end, introduce cpufreq_table_validate_and_sort() and make
the cpufreq core call it right after invoking the ->init() callback
of the driver and destroy the cpufreq policy if the table is invalid.

For the time being the validation of the table happens twice, once
from the driver and then from the core.  The individual drivers will
be updated separately to drop table validation if they don't need it
for other reasons.

The frequency table is marked "sorted" or "unsorted" by the new helper
now instead of in cpufreq_table_validate_and_show(), as it should only
be done after validating the table (which the drivers won't do going
forward).

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject/changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-27 18:22:12 +01:00
Viresh Kumar
b24b6478e6 cpufreq: Reorder cpufreq_online() error code path
Ideally the de-allocation of resources should happen in the exact
opposite order in which they were allocated. It helps maintain the code
in long term, even if nothing really breaks with incorrect ordering.

That wasn't followed in cpufreq_online() and it has some
inconsistencies.  For example, the symlinks were created from within
the locked region while they are removed only after putting the locks.
Also ->exit() should have been called only after the symlinks are
removed and the lock is dropped, as that was the case when ->init()
was first called.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-27 18:22:12 +01:00
Bo Yan
703cbaa601 cpufreq: Skip cpufreq resume if it's not suspended
cpufreq_resume can be called even without preceding cpufreq_suspend.
This can happen in following scenario:

    suspend_devices_and_enter
       --> dpm_suspend_start
          --> dpm_prepare
              --> device_prepare : this function errors out
          --> dpm_suspend: this is skipped due to dpm_prepare failure
                           this means cpufreq_suspend is skipped over
       --> goto Recover_platform, due to previous error
       --> goto Resume_devices
       --> dpm_resume_end
           --> dpm_resume
               --> cpufreq_resume

In case schedutil is used as frequency governor, cpufreq_resume will
eventually call sugov_start, which does following:

    memset(sg_cpu, 0, sizeof(*sg_cpu));
    ....

This effectively erases function pointer for frequency update, causing
crash later on. The function pointer would have been set correctly if
subsequent cpufreq_add_update_util_hook runs successfully, but that
function returns earlier because cpufreq_suspend was not called:

    if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
		return;

The fix is to check cpufreq_suspended first, if it's false, that means
cpufreq_suspend was not called in the first place, so do not resume
cpufreq.

Signed-off-by: Bo Yan <byan@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Dropped printing a message ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-02-05 11:03:33 +01:00
Rafael J. Wysocki
a8b149d32b cpufreq: Fix governor module removal race
It is possible to remove a cpufreq governor module after
cpufreq_parse_governor() has returned success in
store_scaling_governor() and before cpufreq_set_policy()
acquires a reference to it, because the governor list is
not protected during that period and nothing prevents the
governor from being unregistered then.

Prevent that from happening by acquiring an extra reference
to the governor module temporarily in cpufreq_parse_governor(),
under cpufreq_governor_mutex, and dropping it in
store_scaling_governor(), when cpufreq_set_policy() returns.

Note that the second cpufreq_parse_governor() call site is fine,
because it only cares about the policy member of new_policy.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04 15:35:41 +01:00
Rafael J. Wysocki
70d1ff7116 cpufreq: Drop pointless return statement
Drop a pointless return statement from cpufreq_unregister_governor().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04 15:35:41 +01:00
Rafael J. Wysocki
ae0ff89f36 cpufreq: Pass policy pointer to cpufreq_parse_governor()
Pass policy pointer to cpufreq_parse_governor() instead of passing
pointers to two members of it so as to make the code slightly more
straightforward.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04 15:35:41 +01:00
Rafael J. Wysocki
045149e6a2 cpufreq: Clean up cpufreq_parse_governor()
Drop an unnecessary local variable from cpufreq_parse_governor()
and rearrange the code in there to make it easier to follow.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-12-04 15:35:40 +01:00
Dietmar Eggemann
e7d5459dfa cpufreq: provide default frequency-invariance setter function
Frequency-invariant accounting support based on the ratio of current
frequency and maximum supported frequency is an optional feature an arch
can implement.

Since there are cpufreq drivers (e.g. cpufreq-dt) which can be build for
different arch's a default implementation of the frequency-invariance
setter function arch_set_freq_scale() is needed.

This default implementation is an empty weak function which will be
overwritten by a strong function in case the arch provides one.

The setter function passes the cpumask of related (to the frequency
change) cpus (online and offline cpus), the (new) current frequency and
the maximum supported frequency.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-10-03 02:37:53 +02:00
Rafael J. Wysocki
08a10002be Merge branch 'pm-cpufreq-sched'
* pm-cpufreq-sched:
  cpufreq: schedutil: Always process remote callback with slow switching
  cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily
  cpufreq: Return 0 from ->fast_switch() on errors
  cpufreq: Simplify cpufreq_can_do_remote_dvfs()
  cpufreq: Process remote callbacks from any CPU if the platform permits
  sched: cpufreq: Allow remote cpufreq callbacks
  cpufreq: schedutil: Use unsigned int for iowait boost
  cpufreq: schedutil: Make iowait boost more energy efficient
2017-09-04 00:05:22 +02:00
Viresh Kumar
e948bc8fbe cpufreq: Cap the default transition delay value to 10 ms
If transition_delay_us isn't defined by the cpufreq driver, the default
value of transition delay (time after which the cpufreq governor will
try updating the frequency again) is currently calculated by multiplying
transition_latency (nsec) with LATENCY_MULTIPLIER (1000) and then
converting this time to usec. That gives the exact same value as
transition_latency, just that the time unit is usec instead of nsec.

With acpi-cpufreq for example, transition_latency is set to around 10
usec and we get transition delay as 10 ms. Which seems to be a
reasonable amount of time to reevaluate the frequency again.

But for platforms where frequency switching isn't that fast (like ARM),
the transition_latency varies from 500 usec to 3 ms, and the transition
delay becomes 500 ms to 3 seconds. Of course, that is a pretty bad
default value to start with.

We can try to come across a better formula (instead of multiplying with
LATENCY_MULTIPLIER) to solve this problem, but will that be worth it ?

This patch tries a simple approach and caps the maximum value of default
transition delay to 10 ms. Of course, userspace can still come in and
change this value anytime or individual drivers can rather provide
transition_delay_us instead.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-22 15:50:03 +02:00
Viresh Kumar
209887e6b9 cpufreq: Return 0 from ->fast_switch() on errors
CPUFREQ_ENTRY_INVALID is a special symbol which is used to specify that
an entry in the cpufreq table is invalid. But using it outside of the
scope of the cpufreq table looks a bit incorrect.

We can represent an invalid frequency by writing it as 0 instead if we
need. Note that it is already done that way for the return value of the
->get() callback.

Lets do the same for ->fast_switch() and not use CPUFREQ_ENTRY_INVALID
outside of the scope of cpufreq table.

Also update the comment over cpufreq_driver_fast_switch() to clearly
mention what this returns.

None of the drivers return CPUFREQ_ENTRY_INVALID as of now from
->fast_switch() callback and so we don't need to update any of those.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-10 01:26:35 +02:00
Viresh Kumar
fc4c709fc8 cpufreq: Allow dynamic switching with CPUFREQ_ETERNAL latency
With the recent updates, CPUFREQ_ETERNAL is only used by the drivers
which don't know their transition latency but want to use dynamic
switching.

Anyway, the routine cpufreq_policy_transition_delay_us() caps the value
of transition latency to 10 ms now and that can be used safely with such
platforms.

Remove the check from cpufreq_init_governor() and allow dynamic
switching for such configurations as well.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26 00:15:47 +02:00
Viresh Kumar
fe829ed8ef cpufreq: Add CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING cpufreq driver flag
The policy->transition_latency field is used for multiple purposes
today and its not straight forward at all. This is how it is used:

A. Set the correct transition_latency value.

B. Set it to CPUFREQ_ETERNAL because:
   1. We don't want automatic dynamic switching (with
      ondemand/conservative) to happen at all.
   2. We don't know the transition latency.

This patch handles the B.1. case in a more readable way. A new flag for
the cpufreq drivers is added to disallow use of cpufreq governors which
have dynamic_switching flag set.

All the current cpufreq drivers which are setting transition_latency
unconditionally to CPUFREQ_ETERNAL are updated to use it. They don't
need to set transition_latency anymore.

There shouldn't be any functional change after this patch.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26 00:15:46 +02:00
Viresh Kumar
ed4676e254 cpufreq: Replace "max_transition_latency" with "dynamic_switching"
There is no limitation in the ondemand or conservative governors which
disallow the transition_latency to be greater than 10 ms.

The max_transition_latency field is rather used to disallow automatic
dynamic frequency switching for platforms which didn't wanted these
governors to run.

Replace max_transition_latency with a boolean (dynamic_switching) and
check for transition_latency == CPUFREQ_ETERNAL along with that. This
makes it pretty straight forward to read/understand now.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26 00:15:45 +02:00
Viresh Kumar
aa7519af45 cpufreq: Use transition_delay_us for legacy governors as well
The policy->transition_delay_us field is used only by the schedutil
governor currently, and this field describes how fast the driver wants
the cpufreq governor to change CPUs frequency. It should rather be a
common thing across all governors, as it doesn't have any schedutil
dependency here.

Create a new helper cpufreq_policy_transition_delay_us() to get the
transition delay across all governors.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-22 02:25:20 +02:00
Linus Torvalds
408c9861c6 Power management updates for v4.13-rc1
- Rework suspend-to-idle to allow it to take wakeup events signaled
    by the EC into account on ACPI-based platforms in order to properly
    support power button wakeup from suspend-to-idle on recent Dell
    laptops (Rafael Wysocki).
 
    That includes the core suspend-to-idle code rework, support for
    the Low Power S0 _DSM interface, and support for the ACPI INT0002
    Virtual GPIO device from Hans de Goede (required for USB keyboard
    wakeup from suspend-to-idle to work on some machines).
 
  - Stop trying to export the current CPU frequency via /proc/cpuinfo
    on x86 as that is inaccurate and confusing (Len Brown).
 
  - Rework the way in which the current CPU frequency is exported by
    the kernel (over the cpufreq sysfs interface) on x86 systems with
    the APERF and MPERF registers by always using values read from
    these registers, when available, to compute the current frequency
    regardless of which cpufreq driver is in use (Len Brown).
 
  - Rework the PCI/ACPI device wakeup infrastructure to remove the
    questionable and artificial distinction between "devices that
    can wake up the system from sleep states" and "devices that can
    generate wakeup signals in the working state" from it, which
    allows the code to be simplified quite a bit (Rafael Wysocki).
 
  - Fix the wakeup IRQ framework by making it use SRCU instead of
    RCU which doesn't allow sleeping in the read-side critical
    sections, but which in turn is expected to be allowed by the
    IRQ bus locking infrastructure (Thomas Gleixner).
 
  - Modify some computations in the intel_pstate driver to avoid
    rounding errors resulting from them (Srinivas Pandruvada).
 
  - Reduce the overhead of the intel_pstate driver in the HWP
    (hardware-managed P-states) mode and when the "performance"
    P-state selection algorithm is in use by making it avoid
    registering scheduler callbacks in those cases (Len Brown).
 
  - Rework the energy_performance_preference sysfs knob in
    intel_pstate by changing the values that correspond to
    different symbolic hint names used by it (Len Brown).
 
  - Make it possible to use more than one cpuidle driver at the same
    time on ARM (Daniel Lezcano).
 
  - Make it possible to prevent the cpuidle menu governor from using
    the 0 state by disabling it via sysfs (Nicholas Piggin).
 
  - Add support for FFH (Fixed Functional Hardware) MWAIT in ACPI C1
    on AMD systems (Yazen Ghannam).
 
  - Make the CPPC cpufreq driver take the lowest nonlinear performance
    information into account (Prashanth Prakash).
 
  - Add support for hi3660 to the cpufreq-dt driver, fix the
    imx6q driver and clean up the sfi, exynos5440 and intel_pstate
    drivers (Colin Ian King, Krzysztof Kozlowski, Octavian Purdila,
    Rafael Wysocki, Tao Wang).
 
  - Fix a few minor issues in the generic power domains (genpd)
    framework and clean it up somewhat (Krzysztof Kozlowski,
    Mikko Perttunen, Viresh Kumar).
 
  - Fix a couple of minor issues in the operating performance points
    (OPP) framework and clean it up somewhat (Viresh Kumar).
 
  - Fix a CONFIG dependency in the hibernation core and clean it up
    slightly (Balbir Singh, Arvind Yadav, BaoJun Luo).
 
  - Add rk3228 support to the rockchip-io adaptive voltage scaling
    (AVS) driver (David Wu).
 
  - Fix an incorrect bit shift operation in the RAPL power capping
    driver (Adam Lessnau).
 
  - Add support for the EPP field in the HWP (hardware managed
    P-states) control register, HWP.EPP, to the x86_energy_perf_policy
    tool and update msr-index.h with HWP.EPP values (Len Brown).
 
  - Fix some minor issues in the turbostat tool (Len Brown).
 
  - Add support for AMD family 0x17 CPUs to the cpupower tool and fix
    a minor issue in it (Sherry Hurwitz).
 
  - Assorted cleanups, mostly related to the constification of some
    data structures (Arvind Yadav, Joe Perches, Kees Cook, Krzysztof
    Kozlowski).
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Merge tag 'pm-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "The big ticket items here are the rework of suspend-to-idle in order
  to add proper support for power button wakeup from it on recent Dell
  laptops and the rework of interfaces exporting the current CPU
  frequency on x86.

  In addition to that, support for a few new pieces of hardware is
  added, the PCI/ACPI device wakeup infrastructure is simplified
  significantly and the wakeup IRQ framework is fixed to unbreak the IRQ
  bus locking infrastructure.

  Also, there are some functional improvements for intel_pstate, tools
  updates and small fixes and cleanups all over.

  Specifics:

   - Rework suspend-to-idle to allow it to take wakeup events signaled
     by the EC into account on ACPI-based platforms in order to properly
     support power button wakeup from suspend-to-idle on recent Dell
     laptops (Rafael Wysocki).

     That includes the core suspend-to-idle code rework, support for the
     Low Power S0 _DSM interface, and support for the ACPI INT0002
     Virtual GPIO device from Hans de Goede (required for USB keyboard
     wakeup from suspend-to-idle to work on some machines).

   - Stop trying to export the current CPU frequency via /proc/cpuinfo
     on x86 as that is inaccurate and confusing (Len Brown).

   - Rework the way in which the current CPU frequency is exported by
     the kernel (over the cpufreq sysfs interface) on x86 systems with
     the APERF and MPERF registers by always using values read from
     these registers, when available, to compute the current frequency
     regardless of which cpufreq driver is in use (Len Brown).

   - Rework the PCI/ACPI device wakeup infrastructure to remove the
     questionable and artificial distinction between "devices that can
     wake up the system from sleep states" and "devices that can
     generate wakeup signals in the working state" from it, which allows
     the code to be simplified quite a bit (Rafael Wysocki).

   - Fix the wakeup IRQ framework by making it use SRCU instead of RCU
     which doesn't allow sleeping in the read-side critical sections,
     but which in turn is expected to be allowed by the IRQ bus locking
     infrastructure (Thomas Gleixner).

   - Modify some computations in the intel_pstate driver to avoid
     rounding errors resulting from them (Srinivas Pandruvada).

   - Reduce the overhead of the intel_pstate driver in the HWP
     (hardware-managed P-states) mode and when the "performance" P-state
     selection algorithm is in use by making it avoid registering
     scheduler callbacks in those cases (Len Brown).

   - Rework the energy_performance_preference sysfs knob in intel_pstate
     by changing the values that correspond to different symbolic hint
     names used by it (Len Brown).

   - Make it possible to use more than one cpuidle driver at the same
     time on ARM (Daniel Lezcano).

   - Make it possible to prevent the cpuidle menu governor from using
     the 0 state by disabling it via sysfs (Nicholas Piggin).

   - Add support for FFH (Fixed Functional Hardware) MWAIT in ACPI C1 on
     AMD systems (Yazen Ghannam).

   - Make the CPPC cpufreq driver take the lowest nonlinear performance
     information into account (Prashanth Prakash).

   - Add support for hi3660 to the cpufreq-dt driver, fix the imx6q
     driver and clean up the sfi, exynos5440 and intel_pstate drivers
     (Colin Ian King, Krzysztof Kozlowski, Octavian Purdila, Rafael
     Wysocki, Tao Wang).

   - Fix a few minor issues in the generic power domains (genpd)
     framework and clean it up somewhat (Krzysztof Kozlowski, Mikko
     Perttunen, Viresh Kumar).

   - Fix a couple of minor issues in the operating performance points
     (OPP) framework and clean it up somewhat (Viresh Kumar).

   - Fix a CONFIG dependency in the hibernation core and clean it up
     slightly (Balbir Singh, Arvind Yadav, BaoJun Luo).

   - Add rk3228 support to the rockchip-io adaptive voltage scaling
     (AVS) driver (David Wu).

   - Fix an incorrect bit shift operation in the RAPL power capping
     driver (Adam Lessnau).

   - Add support for the EPP field in the HWP (hardware managed
     P-states) control register, HWP.EPP, to the x86_energy_perf_policy
     tool and update msr-index.h with HWP.EPP values (Len Brown).

   - Fix some minor issues in the turbostat tool (Len Brown).

   - Add support for AMD family 0x17 CPUs to the cpupower tool and fix a
     minor issue in it (Sherry Hurwitz).

   - Assorted cleanups, mostly related to the constification of some
     data structures (Arvind Yadav, Joe Perches, Kees Cook, Krzysztof
     Kozlowski)"

* tag 'pm-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (69 commits)
  cpufreq: Update scaling_cur_freq documentation
  cpufreq: intel_pstate: Clean up after performance governor changes
  PM: hibernate: constify attribute_group structures.
  cpuidle: menu: allow state 0 to be disabled
  intel_idle: Use more common logging style
  PM / Domains: Fix missing default_power_down_ok comment
  PM / Domains: Fix unsafe iteration over modified list of domains
  PM / Domains: Fix unsafe iteration over modified list of domain providers
  PM / Domains: Fix unsafe iteration over modified list of device links
  PM / Domains: Handle safely genpd_syscore_switch() call on non-genpd device
  PM / Domains: Call driver's noirq callbacks
  PM / core: Drop run_wake flag from struct dev_pm_info
  PCI / PM: Simplify device wakeup settings code
  PCI / PM: Drop pme_interrupt flag from struct pci_dev
  ACPI / PM: Consolidate device wakeup settings code
  ACPI / PM: Drop run_wake from struct acpi_device_wakeup_flags
  PM / QoS: constify *_attribute_group.
  PM / AVS: rockchip-io: add io selectors and supplies for rk3228
  powercap/RAPL: prevent overridding bits outside of the mask
  PM / sysfs: Constify attribute groups
  ...
2017-07-04 13:39:41 -07:00
Linus Torvalds
9a9594efe5 Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP hotplug updates from Thomas Gleixner:
 "This update is primarily a cleanup of the CPU hotplug locking code.

  The hotplug locking mechanism is an open coded RWSEM, which allows
  recursive locking. The main problem with that is the recursive nature
  as it evades the full lockdep coverage and hides potential deadlocks.

  The rework replaces the open coded RWSEM with a percpu RWSEM and
  establishes full lockdep coverage that way.

  The bulk of the changes fix up recursive locking issues and address
  the now fully reported potential deadlocks all over the place. Some of
  these deadlocks have been observed in the RT tree, but on mainline the
  probability was low enough to hide them away."

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
  cpu/hotplug: Constify attribute_group structures
  powerpc: Only obtain cpu_hotplug_lock if called by rtasd
  ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init
  cpu/hotplug: Remove unused check_for_tasks() function
  perf/core: Don't release cred_guard_mutex if not taken
  cpuhotplug: Link lock stacks for hotplug callbacks
  acpi/processor: Prevent cpu hotplug deadlock
  sched: Provide is_percpu_thread() helper
  cpu/hotplug: Convert hotplug locking to percpu rwsem
  s390: Prevent hotplug rwsem recursion
  arm: Prevent hotplug rwsem recursion
  arm64: Prevent cpu hotplug rwsem recursion
  kprobes: Cure hotplug lock ordering issues
  jump_label: Reorder hotplug lock and jump_label_lock
  perf/tracing/cpuhotplug: Fix locking order
  ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus()
  PCI: Replace the racy recursion prevention
  PCI: Use cpu_hotplug_disable() instead of get_online_cpus()
  perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode()
  x86/perf: Drop EXPORT of perf_check_microcode
  ...
2017-07-03 18:08:06 -07:00
Len Brown
f8475cef90 x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF
The goal of this change is to give users a uniform and meaningful
result when they read /sys/...cpufreq/scaling_cur_freq
on modern x86 hardware, as compared to what they get today.

Modern x86 processors include the hardware needed
to accurately calculate frequency over an interval --
APERF, MPERF, and the TSC.

Here we provide an x86 routine to make this calculation
on supported hardware, and use it in preference to any
driver driver-specific cpufreq_driver.get() routine.

MHz is computed like so:

MHz = base_MHz * delta_APERF / delta_MPERF

MHz is the average frequency of the busy processor
over a measurement interval.  The interval is
defined to be the time between successive invocations
of aperfmperf_khz_on_cpu(), which are expected to to
happen on-demand when users read sysfs attribute
cpufreq/scaling_cur_freq.

As with previous methods of calculating MHz,
idle time is excluded.

base_MHz above is from TSC calibration global "cpu_khz".

This x86 native method to calculate MHz returns a meaningful result
no matter if P-states are controlled by hardware or firmware
and/or if the Linux cpufreq sub-system is or is-not installed.

When this routine is invoked more frequently, the measurement
interval becomes shorter.  However, the code limits re-computation
to 10ms intervals so that average frequency remains meaningful.

Discerning users are encouraged to take advantage of
the turbostat(8) utility, which can gracefully handle
concurrent measurement intervals of arbitrary length.

Signed-off-by: Len Brown <len.brown@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-27 01:47:32 +02:00
David Arcari
6c77003677 cpufreq: cpufreq_register_driver() should return -ENODEV if init fails
For a driver that does not set the CPUFREQ_STICKY flag, if all of the
->init() calls fail, cpufreq_register_driver() should return an error.
This will prevent the driver from loading.

Fixes: ce1bcfe94d (cpufreq: check cpufreq_policy_list instead of scanning policies for all CPUs)
Cc: 4.0+ <stable@vger.kernel.org> # 4.0+
Signed-off-by: David Arcari <darcari@redhat.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-05-30 00:07:20 +02:00
Sebastian Andrzej Siewior
a92551e41d cpufreq: Use cpuhp_setup_state_nocalls_cpuslocked()
cpufreq holds get_online_cpus() while invoking cpuhp_setup_state_nocalls()
to make subsys_interface_register() and the registration of hotplug calls
atomic versus cpu hotplug.

cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.

Use cpuhp_setup/remove_state_nocalls_cpuslocked() to avoid the nested
call. Convert *_online_cpus() to the new interfaces while at it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081547.731628408@linutronix.de
2017-05-26 10:10:38 +02:00