cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
differen

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
differen

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
differen

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
differen

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
differen

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
differen

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
differen

cppc_cpufreq: Fix possible null pointer dereference

[ Upstream commit cf7de25878a1f4508c69dc9f6819c21ba177dbfe ]

cppc_cpufreq_get_rate() and hisi_cppc_cpufreq_get_rate() can be called from
different places with various parameters. So cpufreq_cpu_get() can return
null as 'policy' in some circumstances.
Fix this bug by adding null return check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cpufreq: cppc: Set fie_disabled to FIE_DISABLED if fails to create kworker_fie

The function cppc_freq_invariance_init() may failed to create
kworker_fie, make it more robust by setting fie_disabled

cpufreq: cppc: Set fie_disabled to FIE_DISABLED if fails to create kworker_fie

The function cppc_freq_invariance_init() may failed to create
kworker_fie, make it more robust by setting fie_disabled to FIE_DISBALED
to prevent an invalid pointer dereference in kthread_destroy_worker(),
which called from cppc_freq_invariance_exit().

Signed-off-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

show more ...

cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.

The cpufreq framework used to use the zero of return value to reflect
the cppc_cpufreq_get_rate() had failed to get current fr

cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.

The cpufreq framework used to use the zero of return value to reflect
the cppc_cpufreq_get_rate() had failed to get current frequecy and treat
all positive integer to be succeed. Since cppc_get_perf_ctrs() returns a
negative integer in error case, so it is better to convert the value to
zero as the return value of cppc_cpufreq_get_rate().

Signed-off-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

show more ...

cpufreq: CPPC: Add u64 casts to avoid overflowing

The fields of the _CPC object are unsigned 32-bits values.
To avoid overflows while using _CPC's values, add 'u64' casts.

Signed-off-by: Pierre Gon

cpufreq: CPPC: Add u64 casts to avoid overflowing

The fields of the _CPC object are unsigned 32-bits values.
To avoid overflows while using _CPC's values, add 'u64' casts.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

show more ...

ACPI: CPPC: Disable FIE if registers in PCC regions

PCC regions utilize a mailbox to set/retrieve register values used by
the CPPC code. This is fine as long as the operations are
infrequent. With t

ACPI: CPPC: Disable FIE if registers in PCC regions

PCC regions utilize a mailbox to set/retrieve register values used by
the CPPC code. This is fine as long as the operations are
infrequent. With the FIE code enabled though the overhead can range
from 2-11% of system CPU overhead (ex: as measured by top) on Arm
based machines.

So, before enabling FIE assure none of the registers used by
cppc_get_perf_ctrs() are in the PCC region. Finally, add a module
parameter which can override the PCC region detection at boot or
module reload.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

ACPI: CPPC: Add ACPI disabled check to acpi_cpc_valid()

Make acpi_cpc_valid() check if ACPI is disabled, so that its callers
don't need to check that separately. This will also cause the AMD
pstate

ACPI: CPPC: Add ACPI disabled check to acpi_cpc_valid()

Make acpi_cpc_valid() check if ACPI is disabled, so that its callers
don't need to check that separately. This will also cause the AMD
pstate driver to refuse to load right away when ACPI is disabled.

Also update the warning message in amd_pstate_init() to mention the
ACPI disabled case for completeness.

Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
[ rjw: Subject edits, new changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

cpufreq: CPPC: Fix unused-function warning

Building the cppc_cpufreq driver with for arm64 with
CONFIG_ENERGY_MODEL=n triggers the following warnings:
drivers/cpufreq/cppc_cpufreq.c:550:12: error:

cpufreq: CPPC: Fix unused-function warning

Building the cppc_cpufreq driver with for arm64 with
CONFIG_ENERGY_MODEL=n triggers the following warnings:
drivers/cpufreq/cppc_cpufreq.c:550:12: error: ‘cppc_get_cpu_cost’ defined but not used
[-Werror=unused-function]
550 | static int cppc_get_cpu_cost(struct device *cpu_dev, unsigned long KHz,
| ^~~~~~~~~~~~~~~~~
drivers/cpufreq/cppc_cpufreq.c:481:12: error: ‘cppc_get_cpu_power’ defined but not used
[-Werror=unused-function]
481 | static int cppc_get_cpu_power(struct device *cpu_dev,
| ^~~~~~~~~~~~~~~~~~

Move the Energy Model related functions into specific guards.
This allows to fix the warning and prevent doing extra work
when the Energy Model is not present.

Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information")
Reported-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Tested-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

cpufreq: CPPC: Fix build error without CONFIG_ACPI_CPPC_CPUFREQ_FIE

If CONFIG_ACPI_CPPC_CPUFREQ_FIE is not set, building fails:

drivers/cpufreq/cppc_cpufreq.c: In function ‘populate_efficiency_clas

cpufreq: CPPC: Fix build error without CONFIG_ACPI_CPPC_CPUFREQ_FIE

If CONFIG_ACPI_CPPC_CPUFREQ_FIE is not set, building fails:

drivers/cpufreq/cppc_cpufreq.c: In function ‘populate_efficiency_class’:
drivers/cpufreq/cppc_cpufreq.c:584:2: error: ‘cppc_cpufreq_driver’ undeclared (first use in this function); did you mean ‘cpufreq_driver’?
cppc_cpufreq_driver.register_em = cppc_cpufreq_register_em;
^~~~~~~~~~~~~~~~~~~
cpufreq_driver

Make declare of cppc_cpufreq_driver out of CONFIG_ACPI_CPPC_CPUFREQ_FIE
to fix this.

Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information")
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

cpufreq: CPPC: Enable dvfs_possible_from_any_cpu

The communication mean of the _CPC desired performance can be
PCC, System Memory, System IO, or Functional Fixed Hardware (FFH).

PCC, SystemMemory a

cpufreq: CPPC: Enable dvfs_possible_from_any_cpu

The communication mean of the _CPC desired performance can be
PCC, System Memory, System IO, or Functional Fixed Hardware (FFH).

PCC, SystemMemory and SystemIo address spaces are available from any
CPU. Thus, dvfs_possible_from_any_cpu should be enabled in such case.
For FFH, let the FFH implementation do smp_call_function_*() calls.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-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>

show more ...

cpufreq: CPPC: Enable fast_switch

The communication mean of the _CPC desired performance can be
PCC, System Memory, System IO, or Functional Fixed Hardware.

commit b7898fda5bc7 ("cpufreq: Support f

cpufreq: CPPC: Enable fast_switch

The communication mean of the _CPC desired performance can be
PCC, System Memory, System IO, or Functional Fixed Hardware.

commit b7898fda5bc7 ("cpufreq: Support for fast frequency switching")
fast_switching is 'for switching CPU frequencies from interrupt
context'.
Writes to SystemMemory and SystemIo are fast and suitable this.
This is not the case for PCC and might not be the case for FFH.

Enable fast_switching for the cppc_cpufreq driver in above cases.

Add cppc_allow_fast_switch() to check the desired performance
register address space and set fast_switching accordingly.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-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>

show more ...

cpufreq: CPPC: Register EM based on efficiency class information

Performance states and energy consumption values are not advertised
in ACPI. In the GicC structure of the MADT table, the "Processor

cpufreq: CPPC: Register EM based on efficiency class information

Performance states and energy consumption values are not advertised
in ACPI. In the GicC structure of the MADT table, the "Processor
Power Efficiency Class field" (called efficiency class from now)
allows to describe the relative energy efficiency of CPUs.

To leverage the EM and EAS, the CPPC driver creates a set of
artificial performance states and registers them in the Energy Model
(EM), such as:
- Every 20 capacity unit, a performance state is created.
- The energy cost of each performance state gradually increases.
No power value is generated as only the cost is used in the EM.

During task placement, a task can raise the frequency of its whole
pd. This can make EAS place a task on a pd with CPUs that are
individually less energy efficient.
As cost values are artificial, and to place tasks on CPUs with the
lower efficiency class, a gap in cost values is generated for adjacent
efficiency classes.
E.g.:
- efficiency class = 0, capacity is in [0-1024], so cost values
are in [0: 51] (one performance state every 20 capacity unit)
- efficiency class = 1, capacity is in [0-1024], cost values
are in [1*gap+0: 1*gap+51].

The value of the cost gap is chosen to absorb a the energy of 4 CPUs
at their maximum capacity. This means that between:
1- a pd of 4 CPUs, each of them being used at almost their full
capacity. Their efficiency class is N.
2- a CPU using almost none of its capacity. Its efficiency class is
N+1
EAS will choose the first option.

This patch also populates the (struct cpufreq_driver).register_em
callback if the valid efficiency_class ACPI values are provided.

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

cpufreq: CPPC: Add per_cpu efficiency_class

In ACPI, describing power efficiency of CPUs can be done through the
following arm specific field:
ACPI 6.4, s5.2.12.14 'GIC CPU Interface (GICC) Structur

cpufreq: CPPC: Add per_cpu efficiency_class

In ACPI, describing power efficiency of CPUs can be done through the
following arm specific field:
ACPI 6.4, s5.2.12.14 'GIC CPU Interface (GICC) Structure',
'Processor Power Efficiency Class field':
Describes the relative power efficiency of the associated pro-
cessor. Lower efficiency class numbers are more efficient than
higher ones (e.g. efficiency class 0 should be treated as more
efficient than efficiency class 1). However, absolute values
of this number have no meaning: 2 isn’t necessarily half as
efficient as 1.

The efficiency_class field is stored in the GicC structure of the
ACPI MADT table and it's currently supported in Linux for arm64 only.
Thus, this new functionality is introduced for arm64 only.

To allow the cppc_cpufreq driver to know and preprocess the
efficiency_class values of all the CPUs, add a per_cpu efficiency_class
variable to store them.

At least 2 different efficiency classes must be present,
otherwise there is no use in creating an Energy Model.

The efficiency_class values are squeezed in [0:#efficiency_class-1]
while conserving the order. For instance, efficiency classes of:
[111, 212, 250]
will be mapped to:
[0 (was 111), 1 (was 212), 2 (was 250)].

Each policy being independently registered in the driver, populating
the per_cpu efficiency_class is done only once at the driver
initialization. This prevents from having each policy re-searching the
efficiency_class values of other CPUs. The EM will be registered in a
following patch.

The patch also exports acpi_cpu_get_madt_gicc() to fetch the GicC
structure of the ACPI MADT table for each CPU.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

show more ...

cpufreq: CPPC: Fix performance/frequency conversion

CPUfreq governors request CPU frequencies using information
on current CPU usage. The CPPC driver converts them to
performance requests. Frequency

cpufreq: CPPC: Fix performance/frequency conversion

CPUfreq governors request CPU frequencies using information
on current CPU usage. The CPPC driver converts them to
performance requests. Frequency targets are computed as:
target_freq = (util / cpu_capacity) * max_freq
target_freq is then clamped between [policy->min, policy->max].

The CPPC driver converts performance values to frequencies
(and vice-versa) using cppc_cpufreq_perf_to_khz() and
cppc_cpufreq_khz_to_perf(). These functions both use two different
factors depending on the range of the input value. For
cppc_cpufreq_khz_to_perf():
- (NOMINAL_PERF / NOMINAL_FREQ) or
- (LOWEST_PERF / LOWEST_FREQ)
and for cppc_cpufreq_perf_to_khz():
- (NOMINAL_FREQ / NOMINAL_PERF) or
- ((NOMINAL_PERF - LOWEST_FREQ) / (NOMINAL_PERF - LOWEST_PERF))

This means:
1- the functions are not inverse for some values:
(perf_to_khz(khz_to_perf(x)) != x)
2- cppc_cpufreq_perf_to_khz(LOWEST_PERF) can sometimes give
a different value from LOWEST_FREQ due to integer approximation
3- it is implied that performance and frequency are proportional
(NOMINAL_FREQ / NOMINAL_PERF) == (LOWEST_PERF / LOWEST_FREQ)

This patch changes the conversion functions to an affine function.
This fixes the 3 points above.

Suggested-by: Lukasz Luba <lukasz.luba@arm.com>
Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

show more ...

cpufreq: remove useless INIT_LIST_HEAD()

list cpu_data_list has been inited staticly through LIST_HEAD,
so there's no need to call another INIT_LIST_HEAD. Simply remove
it from cppc_cpufreq_init.

S

cpufreq: remove useless INIT_LIST_HEAD()

list cpu_data_list has been inited staticly through LIST_HEAD,
so there's no need to call another INIT_LIST_HEAD. Simply remove
it from cppc_cpufreq_init.

Signed-off-by: Han Wang <zjuwanghan@outlook.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

show more ...

cpufreq: CPPC: Fix performance/frequency conversion

[ Upstream commit ec1c7ad47664f964c1101fe555b6fde0cb124b38 ]

CPUfreq governors request CPU frequencies using information
on current CPU usage. Th

cpufreq: CPPC: Fix performance/frequency conversion

[ Upstream commit ec1c7ad47664f964c1101fe555b6fde0cb124b38 ]

CPUfreq governors request CPU frequencies using information
on current CPU usage. The CPPC driver converts them to
performance requests. Frequency targets are computed as:
target_freq = (util / cpu_capacity) * max_freq
target_freq is then clamped between [policy->min, policy->max].

The CPPC driver converts performance values to frequencies
(and vice-versa) using cppc_cpufreq_perf_to_khz() and
cppc_cpufreq_khz_to_perf(). These functions both use two different
factors depending on the range of the input value. For
cppc_cpufreq_khz_to_perf():
- (NOMINAL_PERF / NOMINAL_FREQ) or
- (LOWEST_PERF / LOWEST_FREQ)
and for cppc_cpufreq_perf_to_khz():
- (NOMINAL_FREQ / NOMINAL_PERF) or
- ((NOMINAL_PERF - LOWEST_FREQ) / (NOMINAL_PERF - LOWEST_PERF))

This means:
1- the functions are not inverse for some values:
(perf_to_khz(khz_to_perf(x)) != x)
2- cppc_cpufreq_perf_to_khz(LOWEST_PERF) can sometimes give
a different value from LOWEST_FREQ due to integer approximation
3- it is implied that performance and frequency are proportional
(NOMINAL_FREQ / NOMINAL_PERF) == (LOWEST_PERF / LOWEST_FREQ)

This patch changes the conversion functions to an affine function.
This fixes the 3 points above.

Suggested-by: Lukasz Luba <lukasz.luba@arm.com>
Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

cpufreq: CPPC: Add support for frequency invariance

The Frequency Invariance Engine (FIE) is providing a frequency scaling
correction factor that helps achieve more accurate load-tracking.

Normally

cpufreq: CPPC: Add support for frequency invariance

The Frequency Invariance Engine (FIE) is providing a frequency scaling
correction factor that helps achieve more accurate load-tracking.

Normally, this scaling factor can be obtained directly with the help of
the cpufreq drivers as they know the exact frequency the hardware is
running at. But that isn't the case for CPPC cpufreq driver.

Another way of obtaining that is using the arch specific counter
support, which is already present in kernel, but that hardware is
optional for platforms.

This patch updates the CPPC driver to register itself with the topology
core to provide its own implementation (cppc_scale_freq_tick()) of
topology_scale_freq_tick() which gets called by the scheduler on every
tick. Note that the arch specific counters have higher priority than
CPPC counters, if available, though the CPPC driver doesn't need to have
any special handling for that.

On an invocation of cppc_scale_freq_tick(), we schedule an irq work
(since we reach here from hard-irq context), which then schedules a
normal work item and cppc_scale_freq_workfn() updates the per_cpu
arch_freq_scale variable based on the counter updates since the last
tick.

To allow platforms to disable this CPPC counter-based frequency
invariance support, this is all done under CONFIG_ACPI_CPPC_CPUFREQ_FIE,
which is enabled by default.

This also exports sched_setattr_nocheck() as the CPPC driver can be
built as a module.

Cc: linux-acpi@vger.kernel.org
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Qian Cai <quic_qiancai@quicinc.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

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cpufreq: CPPC: Pass structure instance by reference

Don't pass structure instance by value, pass it by reference instead.

Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Ionela

cpufreq: CPPC: Pass structure instance by reference

Don't pass structure instance by value, pass it by reference instead.

Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Qian Cai <quic_qiancai@quicinc.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

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cpufreq: CPPC: Fix potential memleak in cppc_cpufreq_cpu_init

It's a classic example of memleak, we allocate something, we fail and
never free the resources.

Make sure we free all resources on poli

cpufreq: CPPC: Fix potential memleak in cppc_cpufreq_cpu_init

It's a classic example of memleak, we allocate something, we fail and
never free the resources.

Make sure we free all resources on policy ->init() failures.

Fixes: a28b2bfc099c ("cppc_cpufreq: replace per-cpu data array with a list")
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Qian Cai <quic_qiancai@quicinc.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

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cpufreq: CPPC: Migrate to ->exit() callback instead of ->stop_cpu()

Commit 367dc4aa932b ("cpufreq: Add stop CPU callback to cpufreq_driver
interface") added the ->stop_cpu() callback to allow the dr

cpufreq: CPPC: Migrate to ->exit() callback instead of ->stop_cpu()

Commit 367dc4aa932b ("cpufreq: Add stop CPU callback to cpufreq_driver
interface") added the ->stop_cpu() callback to allow the drivers to do
clean up before the CPU is completely down and its state can't be
modified.

At that time the CPU hotplug framework used to call the cpufreq core's
registered notifier for different events like CPU_DOWN_PREPARE and
CPU_POST_DEAD. The ->stop_cpu() callback was called during the
CPU_DOWN_PREPARE event.

This is no longer the case, cpuhp_cpufreq_offline() is called only
once by the CPU hotplug core now and we don't really need two
separate callbacks for cpufreq drivers, i.e. ->stop_cpu() and
-<exit(), as everything can be done from the ->exit() callback
itself.

Migrate to using the ->exit() callback instead of ->stop_cpu().

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Minor edits in the changelog and subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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