cpufreq: intel_pstate: Update default EPPs for Meteor Lake

Update default balanced_performance EPP to 115 and performance EPP to 16.

Changing the balanced_performance EPP has better performance/watt
compared to default powerup EPP value of 128.

Changing the performance EPP to 0x10 shows reduced power for similar
performance as EPP 0. On small form factor devices this is beneficial
as lower power results in lower CPU and skin temperature. This
results in reduced thermal throttling and higher performance.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Allow model specific EPPs

The current implementation allows model specific EPP override for
balanced_performance. Add feature to allow model specific EPP for all
predefined EPP strings. For example for some CPU models, even changing
performance EPP has benefits

Use a mask of EPPs as driver_data instead of just balanced_performance.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: remove cpudata::prev_cummulative_iowait

Commit 09c448d3c61f ("cpufreq: intel_pstate: Use IOWAIT flag in Atom
algorithm") removed the last user of cpudata::prev_cummulative_iowait.
Remove the member too.

Found by https://github.com/jirislaby/clang-struct.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: fix pstate limits enforcement for adjust_perf call back

There is a loophole in pstate limit clamping for the intel_cpufreq CPU
frequency scaling driver (intel_pstate in passive mode), schedutil CPU
frequency scaling governor, HWP (HardWare Pstate) control enabled, when
the adjust_perf call back path is used.

Fix it.

Fixes: a365ab6b9dfb cpufreq: intel_pstate: Implement the ->adjust_perf() callback
Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Refine computation of P-state for given frequency

On systems using HWP, if a given frequency is equal to the maximum turbo
frequency or the maximum non-turbo frequency, the HWP performance level
corresponding to it is already known and can be used directly without
any computation.

Accordingly, adjust the code to use the known HWP performance levels in
the cases mentioned above.

This also helps to avoid limiting CPU capacity artificially in some
cases when the BIOS produces the HWP_CAP numbers using a different
E-core-to-P-core performance scaling factor than expected by the kernel.

Fixes: f5c8cf2a4992 ("cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores")
Cc: 6.1+ <stable@vger.kernel.org> # 6.1+
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Update hybrid scaling factor for Meteor Lake

On some Meteor Lake platforms, maximum one core turbo frequency is not
observed. During hybrid performance to frequency conversion, the maximum
frequency is 100 MHz less. This results in requesting maximum frequency
100 MHz less.

For example when the max one core turbo is 4.9 GHz:
MSR HWP_CAPABILITIES shows highest performance ratio for P-core is 0x3E.
With the current scaling factor of 78741 (1.27x for converting frequency
to performance) results in max frequency of 4.8 GHz. This results in
capping the max scaling frequency as 4.8 GHz, which is 100 MHz less than
the desired.

Add capability to define per CPU model specific scaling factor and define
scaling factor of 80000 (1.25x for converting frequency to performance for
P-cores) for Meteor Lake.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Debug message adjustment, subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add Emerald Rapids support in no-HWP mode

Users may disable HWP in firmware, in which case intel_pstate will give up
unless the CPU model is explicitly supported.

See also the following past commits:

- commit df51f287b5de ("cpufreq: intel_pstate: Add Sapphire Rapids support
in no-HWP mode")
- commit d8de7a44e11f ("cpufreq: intel_pstate: Add Skylake servers support")
- commit 706c5328851d ("cpufreq: intel_pstate: Add Cometlake support in
no-HWP mode")
- commit fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in
no-HWP mode")
- commit 71bb5c82aaae ("cpufreq: intel_pstate: Add Tigerlake support in
no-HWP mode")

Signed-off-by: Zhenguo Yao <yaozhenguo1@gmail.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Prioritize firmware-provided balance performance EPP

The platform firmware can provide a balance performance EPP value by
enabling HWP and programming the EPP to the desired value.

However, currently this only takes effect for processors listed in
intel_epp_balance_perf[], so in order to enable a new processor model
to utilize this mechanism, that table needs to be updated. It arguably
should not be necessary to modify the kernel to work properly with
every new generation of processors, though, and distributions that don't
always ship the most recent kernels should be able to run reasonably well
on new hardware without code changes.

For this reason, move the check to avoid updating the EPP when the balance
performance EPP is unmodified from the power-up default of 0x80 after the
check that allows the firmware-provided balance performance EPP value to
be retrieved. This will cause the code to always look for the firmware-
provided value before consulting intel_epp_balance_perf[] and the handling
of new hardware will not depend on whether or not that thable has been
updated yet.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Revise global turbo disable check

Setting global turbo flag based on CPU 0 P-state limits is problematic
as it limits max P-state request on every CPU on the system just based
on its P-state limits.

There are two cases in which global.turbo_disabled flag is set:
- When the MSR_IA32_MISC_ENABLE_TURBO_DISABLE bit is set to 1
in the MSR MSR_IA32_MISC_ENABLE. This bit can be only changed by
the system BIOS before power up.
- When the max non turbo P-state is same as max turbo P-state for CPU 0.

The second check is not a valid to decide global turbo state based on
the CPU 0. CPU 0 max turbo P-state can be same as max non turbo P-state,
but for other CPUs this may not be true.

There is no guarantee that max P-state limits are same for every CPU. This
is possible that during fusing max P-state for a CPU is constrained. Also
with the Intel Speed Select performance profile, CPU 0 may not be present
in all profiles. In this case the max non turbo and turbo P-state can be
set to the lowest possible P-state by the hardware when switched to
such profile. Since max non turbo and turbo P-state is same,
global.turbo_disabled flag will be set.

Once global.turbo_disabled is set, any scaling max and min frequency
update for any CPU will result in its max P-state constrained to the max
non turbo P-state.

Hence remove the check of max non turbo P-state equal to max turbo P-state
of CPU 0 to set global turbo disabled flag.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: set stale CPU frequency to minimum

The intel_pstate CPU frequency scaling driver does not
use policy->cur and it is 0.
When the CPU frequency is outdated arch_freq_get_on_cpu()
will default to the nominal clock frequency when its call to
cpufreq_quick_getpolicy_cur returns the never updated 0.
Thus, the listed frequency might be outside of currently
set limits. Some users are complaining about the high
reported frequency, albeit stale, when their system is
idle and/or it is above the reduced maximum they have set.

This patch will maintain policy_cur for the intel_pstate
driver at the current minimum CPU frequency.

Reported-by: Yang Jie <yang.jie@linux.intel.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217597
Signed-off-by: Doug Smythies <dsmythies@telus.net>
[ rjw: White space damage fixes and comment adjustment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix scaling for hybrid-capable systems with disabled E-cores

Some system BIOS configuration may provide option to disable E-cores.
As part of this change, CPUID feature for hybrid (Leaf 7 sub leaf 0,
EDX[15] = 0) may not be set. But HWP performance limits will still be
using a scaling factor like any other hybrid enabled system.

The current check for applying scaling factor will fail when hybrid
CPUID feature is not set and the only way to make sure that scaling
should be applied by checking CPPC nominal frequency and nominal
performance.

First, or systems predating Alder Lake, the CPPC nominal frequency and
nominal performance are 0, which can be used to distinguish those
systems from hybrid systems with disabled E-cores.

Second, if the CPPC nominal frequency and nominal performance are
defined, which indicates the need to use a special scaling factor, and
the nominal performance value multiplied by 100 is not equal to the
nominal frequency one, use hybrid scaling factor.

This can be done for all HWP systems without additional CPU model check.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject and changelog edits, removal of unneeded parens, comment
edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix energy_performance_preference for passive

If the intel_pstate driver is set to passive mode, then writing the
same value to the energy_performance_preference sysfs twice will fail.
This is caused by the wrong return value used (index of the matched
energy_perf_string), instead of the length of the passed in parameter.
Fix by forcing the internal return value to zero when the same
preference is passed in by user. This same issue is not present when
active mode is used for the driver.

Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled")
Reported-by: Niklas Neronin <niklas.neronin@intel.com>
Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: move to use bus_get_dev_root()

Direct access to the struct bus_type dev_root pointer is going away soon
so replace that with a call to bus_get_dev_root() instead, which is what
it is there for.

Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-pm@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20230313182918.1312597-3-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

cpufreq: intel_pstate: Enable HWP IO boost for all servers

The HWP IO boost results in slight improvements for IO performance on
both Ice Lake and Sapphire Rapid servers.

Currently there is a CPU model check for Skylake desktop and server along
with the ACPI PM profile for performance and enterprise servers to enable
IO boost.

Remove the CPU model check, so that all current server models enable HWP
IO boost by default.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4454e ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Adjust balance_performance EPP for Sapphire Rapids

While the majority of server OS distributions are deployed with the
"performance" governor as the default, some distributions like Ubuntu use
the "powersave" governor by default.

While using the "powersave" governor in its default configuration on
Sapphire Rapids systems leads to much lower power, the performance is
lower by more than 25% for several workloads relative to the
"performance" governor.

A 37% difference has been reported by www.Phoronix.com [1].

This is a consequence of using a relatively high EPP value in the
default configuration of the "powersave" governor and the performance
can be made much closer to the "performance" governor's level by
adjusting the default EPP value. Based on experiments, with EPP of 0x00,
0x10, 0x20, the performance delta between the "powersave" governor and
the "performance" one is around 12%. However, the EPP of 0x20 reduces
average power by 18% with respect to the lower EPP values.

[Note that raising min_perf_pct in sysfs as high as 50% in addition to
adjusting EPP does not improve the performance any further.]

For this reason, change the EPP value corresponding to the the default
balance_performance setting for Sapphire Rapids to 0x20, which is
straightforward, because analogous default EPP adjustment has been
applied to Alder Lake and there is a way to set the balance_performance
EPP value in intel_pstate based on the processor model already.

The goal here is to limit the mean performance delta between the
"powersave" governor in the default configuration and the "performance"
governor for a wide variety of server workloadsto to around 10-12%. For
some bursty workloads, this delta can be still large, as the frequency
ramp-up will still lag when the "powersave" governor is in use
irrespective of the EPP setting, because the performance governor always
requests the maximum possible frequency.

Link: https://www.phoronix.com/review/centos-clear-spr/6 # [1]
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop ACPI _PSS states table patching

After making acpi_processor_get_platform_limit() use the "no limit"
value for its frequency QoS request when _PPC returns 0, it is not
necessary to replace the frequency corresponding to the first _PSS
return package entry with the maximum turbo frequency of the given
CPU in intel_pstate_init_acpi_perf_limits() any more, so drop the
code doing that along with the comment explaining it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add Sapphire Rapids support in no-HWP mode

Users may disable HWP in firmware, in which case intel_pstate wouldn't load
unless the CPU model is explicitly supported.

See also the following past commits:

commit d8de7a44e11f ("cpufreq: intel_pstate: Add Skylake servers support")
commit 706c5328851d ("cpufreq: intel_pstate: Add Cometlake support in
no-HWP mode")
commit fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in
no-HWP mode")
commit 71bb5c82aaae ("cpufreq: intel_pstate: Add Tigerlake support in
no-HWP mode")

Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Allow EPP 0x80 setting by the firmware

With the
"commit 3d13058ed2a6 ("cpufreq: intel_pstate: Use firmware default EPP")"
the firmware can set an EPP, which driver will not overwrite. But the
driver has a valid range check for:
0x40 > firmware epp < 0x80.
Hence firmware can't specify EPP of 0x80.

If the firmware didn't specify in the valid range, the driver has a
hard coded EPP of 102. But some Chrome hardware vendors don't want
this overwrite and wants to boot with chipset default EPP of 0x80 as
this improves battery life.

In this case they want to have capability to specify EPP of 0x80 via
the firmware. This require the valid range to include 0x80 also.
But here the valid range can't be simply extended to include 0x80 as
this is the chipset default EPP. Even without any firmware specifying
EPP, the chipset will always boot with EPP of 0x80.

To make sure that firmware specified EPP of 0x80 and not by the
chipset default, it will require additional check to make sure HWP
was enabled by the firmware before boot. Only way the firmware can
update EPP, is to enable HWP and update EPP via MSR_HWP_REQUEST.

This driver already checks, if the HWP is enabled by the firmware.
Use the same flag and extend valid range to include 0x80.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores

Commit 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP
calibration") attempted to use the information from CPPC (the nominal
performance in particular) to obtain the scaling factor allowing the
frequency to be computed if the HWP performance level of the given CPU
is known or vice versa.

However, it turns out that on some platforms this doesn't work, because
the CPPC information on them does not align with the contents of the
MSR_HWP_CAPABILITIES registers.

This basically means that the only way to make intel_pstate work on all
of the hybrid platforms to date is to use the observation that on all
of them the scaling factor between the HWP performance levels and
frequency for P-cores is 78741 (approximately 100000/1.27). For
E-cores it is 100000, which is the same as for all of the non-hybrid
"core" platforms and does not require any changes.

Accordingly, make intel_pstate use 78741 as the scaling factor between
HWP performance levels and frequency for P-cores on all hybrid platforms
and drop the dependency of the HWP calibration code on CPPC.

Fixes: 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP calibration")
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 5.15+ <stable@vger.kernel.org> # 5.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Read all MSRs on the target CPU

Some of the MSR accesses in intel_pstate are carried out on the CPU
that is running the code, but the values coming from them are used
for the performance scaling of the other CPUs.

This is problematic, for example, on hybrid platforms where
MSR_TURBO_RATIO_LIMIT for P-cores and E-cores is different, so the
values read from it on a P-core are generally not applicable to E-cores
and the other way around.

For this reason, make the driver access all MSRs on the target CPU on
platforms using the "core" pstate_funcs callbacks which is the case for
all of the hybrid platforms released to date. For this purpose, pass
a CPU argument to the ->get_max(), ->get_max_physical(), ->get_min()
and ->get_turbo() pstate_funcs callbacks and from there pass it to
rdmsrl_on_cpu() or rdmsrl_safe_on_cpu() to access the MSR on the target
CPU.

Fixes: 46573fd6369f ("cpufreq: intel_pstate: hybrid: Rework HWP calibration")
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 5.15+ <stable@vger.kernel.org> # 5.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add Tigerlake support in no-HWP mode

Users may disable HWP in firmware, in which case intel_pstate wouldn't load
unless the CPU model is explicitly supported.

Add TIGERLAKE to the list of CPUs that can register intel_pstate while not
advertising the HWP capability. Without this change, an TIGERLAKE in no-HWP
mode could only use the acpi_cpufreq frequency scaling driver.

See also commits:
d8de7a44e11f: cpufreq: intel_pstate: Add Skylake servers support
fbdc21e9b038: cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode
706c5328851d: cpufreq: intel_pstate: Add Cometlake support in no-HWP mode

Reported by: M. Cargi Ari <cagriari@pm.me>
Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Support Sapphire Rapids OOB mode

Prevent intel_pstate to load when OOB (Out Of Band) P-states mode is
enabled in Sapphire Rapids. The OOB identifying bits are same as the
prior generation CPUs like Ice Lake servers. So, also add Sapphire
Rapids to intel_pstate_cpu_oob_ids list.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Handle no_turbo in frequency invariance

Problem statement:

Once the user has disabled turbo frequency by

# echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo

the cfs_rq's util_avg becomes quite small when compared with
CPU capacity.

Step to reproduce:

# echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo

# ./x86_cpuload --count 1 --start 3 --timeout 100 --busy 99

would launch 1 thread and bind it to CPU3, lasting for 100 seconds,
with a CPU utilization of 99%. [1]

top result:
%Cpu3 : 98.4 us, 0.0 sy, 0.0 ni, 1.6 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st

check util_avg:
cat /sys/kernel/debug/sched/debug | grep "cfs_rq\[3\]" -A 20 | grep util_avg
.util_avg : 611

So the util_avg/cpu capacity is 611/1024, which is much smaller than
98.4% shown in the top result.

This might impact some logic in the scheduler. For example,
group_is_overloaded() would compare the group_capacity and group_util
in the sched group, to check if this sched group is overloaded or not.
With this gap, even when there is a nearly 100% workload, the sched
group will not be regarded as overloaded. Besides group_is_overloaded(),
there are also other victims. There is a ongoing work that aims to
optimize the task wakeup in a LLC domain. The main idea is to stop
searching idle CPUs if the sched domain is overloaded[2]. This proposal
also relies on the util_avg/CPU capacity to decide whether the LLC
domain is overloaded.

Analysis:

CPU frequency invariance has caused this difference. In summary,
the util_sum of cfs rq would decay quite fast when the CPU is in
idle, when the CPU frequency invariance is enabled.

The detail is as followed:

As depicted in update_rq_clock_pelt(), when the frequency invariance
is enabled, there would be two clock variables on each rq, clock_task
and clock_pelt:

The clock_pelt scales the time to reflect the effective amount of
computation done during the running delta time but then syncs back to
clock_task when rq is idle.

absolute time | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16
@ max frequency ------******---------------******---------------
@ half frequency ------************---------************---------
clock pelt | 1| 2| 3| 4| 7| 8| 9| 10| 11|14|15|16

The fast decay of util_sum during idle is due to:

1. rq->clock_pelt is always behind rq->clock_task
2. rq->last_update is updated to rq->clock_pelt' after invoking
___update_load_sum()
3. Then the CPU becomes idle, the rq->clock_pelt' would be suddenly
increased a lot to rq->clock_task
4. Enters ___update_load_sum() again, the idle period is calculated by
rq->clock_task - rq->last_update, AKA, rq->clock_task - rq->clock_pelt'.
The lower the CPU frequency is, the larger the delta =
rq->clock_task - rq->clock_pelt' will be. Since the idle period will be
used to decay the util_sum only, the util_sum drops significantly during
idle period.

Proposal:

This symptom is not only caused by disabling turbo frequency, but it
would also appear if the user limits the max frequency at runtime.

Because, if the frequency is always lower than the max frequency,
CPU frequency invariance would decay the util_sum quite fast during
idle.

As some end users would disable turbo after boot up, this patch aims to
present this symptom and deals with turbo scenarios for now.

It might be ideal if CPU frequency invariance is aware of the max CPU
frequency (user specified) at runtime in the future.

Link: https://github.com/yu-chen-surf/x86_cpuload.git #1
Link: https://lore.kernel.org/lkml/20220310005228.11737-1-yu.c.chen@intel.com/ #2
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use firmware default EPP

For some specific platforms (E.g. AlderLake) the balance performance
EPP is updated from the hard coded value in the driver. This acts as
the default and balance_performance EPP. The purpose of this EPP
update is to reach maximum 1 core turbo frequency (when possible) out
of the box.

Although we can achieve the objective by using hard coded value in the
driver, there can be other EPP which can be better in terms of power.
But that will be very subjective based on platform and use cases.
This is not practical to have a per platform specific default hard coded
in the driver.

If a platform wants to specify default EPP, it can be set in the firmware.
If this EPP is not the chipset default of 0x80 (balance_perf_epp unless
driver changed it) and more performance oriented but not 0, the driver
can use this as the default and balanced_perf EPP. In this case no driver
update is required every time there is some new platform and default EPP.

If the firmware didn't update the EPP from the chipset default then
the hard coded value is used as per existing implementation.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Update cpuinfo.max_freq on HWP_CAP changes

With HWP enabled, when the turbo range of performance levels is
disabled by the platform firmware, the CPU capacity is given by
the "guaranteed performance" field in MSR_HWP_CAPABILITIES which
is generally dynamic. When it changes, the kernel receives an HWP
notification interrupt handled by notify_hwp_interrupt().

When the "guaranteed performance" value changes in the above
configuration, the CPU performance scaling needs to be adjusted so
as to use the new CPU capacity in computations, which means that
the cpuinfo.max_freq value needs to be updated for that CPU.

Accordingly, modify intel_pstate_notify_work() to read
MSR_HWP_CAPABILITIES and update cpuinfo.max_freq to reflect the
new configuration (this update can be carried out even if the
configuration doesn't actually change, because it simply doesn't
matter then and it takes less time to update it than to do extra
checks to decide whether or not a change has really occurred).

Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Update EPP for AlderLake mobile

There is an expectation from users that they can get frequency specified
by cpufreq/cpuinfo_max_freq when conditions permit. But with AlderLake
mobile it may not be possible. This is possible that frequency is clipped
based on the system power-up EPP value. In this case users can update
cpufreq/energy_performance_preference to some performance oriented EPP to
limit clipping of frequencies.

To get out of box behavior as the prior generations of CPUs, update EPP
for AlderLake mobile CPUs on boot. On prior generations of CPUs EPP = 128
was enough to get maximum frequency, but with AlderLake mobile the
equivalent EPP is 102. Since EPP is model specific, this is possible that
they have different meaning on each generation of CPU.

The current EPP string "balance_performance" corresponds to EPP = 128.
Change the EPP corresponding to "balance_performance" to 102 for only
AlderLake mobile CPUs and update this on each CPU during boot.

To implement reuse epp_values[] array and update the modified EPP at the
index for BALANCE_PERFORMANCE. Add a dummy EPP_INDEX_DEFAULT to
epp_values[] to match indexes in the energy_perf_strings[].

After HWP PM is enabled also update EPP when "balance_performance" is
redefined for the very first time after the boot on each CPU. On
subsequent suspend/resume or offline/online the old EPP is restored,
so no specific action is needed.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop redundant intel_pstate_get_hwp_cap() call

It is not necessary to call intel_pstate_get_hwp_cap() from
intel_pstate_update_perf_limits(), because it gets called from
intel_pstate_verify_cpu_policy() which is either invoked directly
right before intel_pstate_update_perf_limits(), in
intel_cpufreq_verify_policy() in the passive mode, or called
from driver callbacks in a sequence that causes it to be followed
by an immediate intel_pstate_update_perf_limits().

Namely, in the active mode intel_cpufreq_verify_policy() is called
by intel_pstate_verify_policy() which is the ->verify() callback
routine of intel_pstate and gets called by the cpufreq core right
before intel_pstate_set_policy(), which is the driver's ->setoplicy()
callback routine, where intel_pstate_update_perf_limits() is called.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: ITMT support for overclocked system

On systems with overclocking enabled, CPPC Highest Performance can be
hard coded to 0xff. In this case even if we have cores with different
highest performance, ITMT can't be enabled as the current implementation
depends on CPPC Highest Performance.

On such systems we can use MSR_HWP_CAPABILITIES maximum performance field
when CPPC.Highest Performance is 0xff.

Due to legacy reasons, we can't solely depend on MSR_HWP_CAPABILITIES as
in some older systems CPPC Highest Performance is the only way to identify
different performing cores.

Reported-by: Michael Larabel <Michael@MichaelLarabel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Michael Larabel <Michael@MichaelLarabel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix active mode offline/online EPP handling

After commit 4adcf2e5829f ("cpufreq: intel_pstate: Add ->offline and
->online callbacks") the EPP value set by the "performance" scaling
algorithm in the active mode is not restored after an offline/online
cycle which replaces it with the saved EPP value coming from user
space.

Address this issue by forcing intel_pstate_hwp_set() to set a new
EPP value when it runs first time after online.

Fixes: 4adcf2e5829f ("cpufreq: intel_pstate: Add ->offline and ->online callbacks")
Link: https://lore.kernel.org/linux-pm/adc7132c8655bd4d1c8b6129578e931a14fe1db2.camel@linux.intel.com/
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add Ice Lake server to out-of-band IDs

Commit fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers
support in no-HWP mode") enabled the use of Intel P-State driver
for Ice Lake servers.

But it doesn't cover the case when OS can't control P-States.

Therefore, for Ice Lake server, if MSR_MISC_PWR_MGMT bits 8 or 18
are enabled, then the Intel P-State driver should exit as OS can't
control P-States.

Fixes: fbdc21e9b038 ("cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode")
Signed-off-by: Adamos Ttofari <attofari@amazon.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Clear HWP Status during HWP Interrupt enable

It is possible that some performance excursions happened before OS boot
or enable HWP interrupts. So clear MSR_HWP_STATUS bits when we enable
HWP interrupt. In this way a next excursion will results in a HWP
interrupt.

The status bits of MSR_HWP_STATUS must be cleared (0) by software so
that a new status condition change will cause the hardware to set the
bit again and issue the notification.

Fixes: 57577c996d73 ("cpufreq: intel_pstate: Process HWP Guaranteed change notification")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix unchecked MSR 0x773 access

It is possible that on some platforms HWP interrupts are disabled. In
that case accessing MSR 0x773 will result in warning.

So check X86_FEATURE_HWP_NOTIFY feature to access MSR 0x773. The other
places in code where this MSR is accessed, already checks this feature
except during disable path called during cpufreq offline and suspend
callbacks.

Fixes: 57577c996d73 ("cpufreq: intel_pstate: Process HWP Guaranteed change notification")
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Clear HWP desired on suspend/shutdown and offline

Commit a365ab6b9dfb ("cpufreq: intel_pstate: Implement the
->adjust_perf() callback") caused intel_pstate to use nonzero HWP
desired values in certain usage scenarios, but it did not prevent
them from being leaked into the confugirations in which HWP desired
is expected to be 0.

The failing scenarios are switching the driver from the passive
mode to the active mode and starting a new kernel via kexec() while
intel_pstate is running in the passive mode.

To address this issue, ensure that HWP desired will be cleared on
offline and suspend/shutdown.

Fixes: a365ab6b9dfb ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback")
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Tested-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix cpu->pstate.turbo_freq initialization

Fix a problem in active mode that cpu->pstate.turbo_freq is initialized
only if HWP-to-frequency scaling factor is refined.

In passive mode, this problem is not exposed, because
cpu->pstate.turbo_freq is set again, later in
intel_cpufreq_cpu_init()->intel_pstate_get_hwp_cap().

Fixes: eb3693f0521e ("cpufreq: intel_pstate: hybrid: CPU-specific scaling factor")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Process HWP Guaranteed change notification

It is possible that HWP guaranteed ratio is changed in response to
change in power and thermal limits. For example when Intel Speed Select
performance profile is changed or there is change in TDP, hardware can
send notifications. It is possible that the guaranteed ratio is
increased. This creates an issue when turbo is disabled, as the old
limits set in MSR_HWP_REQUEST are still lower and hardware will clip
to older limits.

This change enables HWP interrupt and process HWP interrupts. When
guaranteed is changed, calls cpufreq_update_policy() so that driver
callbacks are called to update to new HWP limits. This callback
is called from a delayed workqueue of 10ms to avoid frequent updates.

Although the scope of IA32_HWP_INTERRUPT is per logical cpu, on some
plaforms interrupt is generated on all CPUs. This is particularly a
problem during initialization, when the driver didn't allocated
data for other CPUs. So this change uses a cpumask of enabled CPUs and
process interrupts on those CPUs only.

When the cpufreq offline() or suspend() callback is called, HWP interrupt
is disabled on those CPUs and also cancels any pending work item.

Spin lock is used to protect data and processing shared with interrupt
handler. Here READ_ONCE(), WRITE_ONCE() macros are used to designate
shared data, even though spin lock act as an optimization barrier here.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: pablomh@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Override parameters if HWP forced by BIOS

If HWP has been already been enabled by BIOS, it may be
necessary to override some kernel command line parameters.
Once it has been enabled it requires a reset to be disabled.

Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: hybrid: Rework HWP calibration

The current HWP calibration for hybrid processors in intel_pstate is
fragile, because it depends too much on the information provided by
the platform firmware via CPPC which may not be reliable enough. It
also need not be so complicated.

In order to improve that mechanism and make it more resistant to
platform firmware issues, make it only use the CPPC nominal_perf
values to compute the HWP-to-frequency scaling factors for all
CPUs and possibly use the HWP_CAP highest_perf values to recompute
them if the ones derived from the CPPC nominal_perf values alone
appear to be too high.

Namely, fetch CPC.nominal_perf for all CPUs present in the system,
find the minimum one and use it as a reference for computing all of
the CPUs' scaling factors (using the observation that for the CPUs
having the minimum CPC.nominal_perf the HWP range of available
performance levels should be the same as the range of available
"legacy" P-states and so the HWP-to-frequency scaling factor for
them should be the same as the corresponding scaling factor used
for representing the P-state values in kHz).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Zhang Rui <rui.zhang@intel.com>

Revert "cpufreq: intel_pstate: Process HWP Guaranteed change notification"

Revert commit d0e936adbd22 ("cpufreq: intel_pstate: Process HWP
Guaranteed change notification"), because it causes a NULL pointer
dereference to occur on Lenovo X1 gen9 laptops due to an HWP
guaranteed performance change interrupt arriving prematurely.

This feature will be revisited in the next cycle.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Process HWP Guaranteed change notification

It is possible that HWP guaranteed ratio is changed in response to
change in power and thermal limits. For example when Intel Speed Select
performance profile is changed or there is change in TDP, hardware can
send notifications. It is possible that the guaranteed ratio is
increased. This creates an issue when turbo is disabled, as the old
limits set in MSR_HWP_REQUEST are still lower and hardware will clip
to older limits.

This change enables HWP interrupt and process HWP interrupts. When
guaranteed is changed, calls cpufreq_update_policy() so that driver
callbacks are called to update to new HWP limits. This callback
is called from a delayed workqueue of 10ms to avoid frequent updates.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Replace deprecated CPU-hotplug functions

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Combine ->stop_cpu() and ->offline()

Combine the ->stop_cpu() and ->offline() callback routines for
intel_pstate in the active mode so as to avoid setting the
->stop_cpu callback pointer which is going to be dropped from
the framework.

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

cpufreq: intel_pstate: hybrid: Fix build with CONFIG_ACPI unset

One of the previous commits introducing hybrid processor support to
intel_pstate broke build with CONFIG_ACPI unset.

Fix that and while at it make empty stubs of two functions related
to ACPI CPPC static inline and fix a spelling mistake in the name of
one of them.

Fixes: eb3693f0521e ("cpufreq: intel_pstate: hybrid: CPU-specific scaling factor")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested

cpufreq: intel_pstate: Add Cometlake support in no-HWP mode

Users may disable HWP in firmware, in which case intel_pstate wouldn't load
unless the CPU model is explicitly supported.

See also commit d8de7a44e11f ("cpufreq: intel_pstate: Add Skylake servers
support").

Suggested-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode

Users may disable HWP in firmware, in which case intel_pstate wouldn't load
unless the CPU model is explicitly supported.

Add ICELAKE_X to the list of CPUs that can register intel_pstate while not
advertising the HWP capability. Without this change, an ICELAKE_X in no-HWP
mode could only use the acpi_cpufreq frequency scaling driver.

See also commit d8de7a44e11f ("cpufreq: intel_pstate: Add Skylake servers
support").

Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: hybrid: CPU-specific scaling factor

The scaling factor between HWP performance levels and CPU frequency
may be different for different types of CPUs in a hybrid processor
and in general the HWP performance levels need not correspond to
"P-states" representing values that would be written to
MSR_IA32_PERF_CTL if HWP was disabled.

However, the policy limits control in cpufreq is defined in terms
of CPU frequency, so it is necessary to map the frequency limits set
through that interface to HWP performance levels with reasonable
accuracy and the behavior of that interface on hybrid processors
has to be compatible with its behavior on non-hybrid ones.

To address this problem, use the observations that (1) on hybrid
processors the sysfs interface can operate by mapping frequency
to "P-states" and translating those "P-states" to specific HWP
performance levels of the given CPU and (2) the scaling factor
between the MSR_IA32_PERF_CTL "P-states" and CPU frequency can be
regarded as a known value. Moreover, the mapping between the
HWP performance levels and CPU frequency can be assumed to be
linear and such that HWP performance level 0 correspond to the
frequency value of 0, so it is only necessary to know the
frequency corresponding to one specific HWP performance level
to compute the scaling factor applicable to all of them.

One possibility is to take the nominal performance value from CPPC,
if available, and use cpu_khz as the corresponding frequency. If
the CPPC capabilities interface is not there or the nominal
performance value provided by it is out of range, though, something
else needs to be done.

Namely, the guaranteed performance level either from CPPC or from
MSR_HWP_CAPABILITIES can be used instead, but the corresponding
frequency needs to be determined. That can be done by computing the
product of the (known) scaling factor between the MSR_IA32_PERF_CTL
P-states and CPU frequency (the PERF_CTL scaling factor) and the
P-state value referred to as the "TDP ratio".

If the HWP-to-frequency scaling factor value obtained in one of the
ways above turns out to be euqal to the PERF_CTL scaling factor, it
can be assumed that the number of HWP performance levels is equal to
the number of P-states and the given CPU can be handled as though
this was not a hybrid processor.

Otherwise, one more adjustment may still need to be made, because the
HWP-to-frequency scaling factor computed so far may not be accurate
enough (e.g. because the CPPC information does not match the exact
behavior of the processor). Specifically, in that case the frequency
corresponding to the highest HWP performance value from
MSR_HWP_CAPABILITIES (computed as the product of that value and the
HWP-to-frequency scaling factor) cannot exceed the frequency that
corresponds to the maximum 1-core turbo P-state value from
MSR_TURBO_RATIO_LIMIT (computed as the procuct of that value and the
PERF_CTL scaling factor) and the HWP-to-frequency scaling factor may
need to be adjusted accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: hybrid: Avoid exposing two global attributes

The turbo_pct and num_pstates sysfs attributes represent CPU
properties that may be different for differenty types of CPUs in
a hybrid processor, so avoid exposing them in that case.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use HWP if enabled by platform firmware

It turns out that there are systems where HWP is enabled during
initialization by the platform firmware (BIOS), but HWP EPP support
is not advertised.

After commit 7aa1031223bc ("cpufreq: intel_pstate: Avoid enabling HWP
if EPP is not supported") intel_pstate refuses to use HWP on those
systems, but the fallback PERF_CTL interface does not work on them
either because of enabled HWP, and once enabled, HWP cannot be
disabled. Consequently, the users of those systems cannot control
CPU performance scaling.

Address this issue by making intel_pstate use HWP unconditionally if
it is enabled already when the driver starts.

Fixes: 7aa1031223bc ("cpufreq: intel_pstate: Avoid enabling HWP if EPP is not supported")
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+

cpufreq: intel_pstate: Simplify intel_pstate_update_perf_limits()

Because pstate.max_freq is always equal to the product of
pstate.max_pstate and pstate.scaling and, analogously,
pstate.turbo_freq is always equal to the product of
pstate.turbo_pstate and pstate.scaling, the result of the
max_policy_perf computation in intel_pstate_update_perf_limits() is
always equal to the quotient of policy_max and pstate.scaling,
regardless of whether or not turbo is disabled. Analogously, the
result of min_policy_perf in intel_pstate_update_perf_limits() is
always equal to the quotient of policy_min and pstate.scaling.

Accordingly, intel_pstate_update_perf_limits() need not check
whether or not turbo is enabled at all and in order to compute
max_policy_perf and min_policy_perf it can always divide policy_max
and policy_min, respectively, by pstate.scaling. Make it do so.

While at it, move the definition and initialization of the
turbo_max local variable to the code branch using it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>

cpufreq: intel_pstate: Clean up frequency computations

Notice that some computations related to frequency in intel_pstate
can be simplified if (a) intel_pstate_get_hwp_max() updates the
relevant members of struct cpudata by itself and (b) the "turbo
disabled" check is moved from it to its callers, so modify the code
accordingly and while at it rename intel_pstate_get_hwp_max() to
intel_pstate_get_hwp_cap() which better reflects its purpose and
provide a simplified variat of it, __intel_pstate_get_hwp_cap(),
suitable for the initialization path.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>

cpufreq: intel_pstate: Remove repeated word

In the comment for trace in passive mode there is an
unnecessary "the". Eradicate it.

Signed-off-by: Nigel Christian <nigel.l.christian@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Get per-CPU max freq via MSR_HWP_CAPABILITIES if available

Currently, when turbo is disabled (either by BIOS or by the user),
the intel_pstate driver reads the max non-turbo frequency from the
package-wide MSR_PLATFORM_INFO(0xce) register.

However, on asymmetric platforms it is possible in theory that small
and big core with HWP enabled might have different max non-turbo CPU
frequency, because MSR_HWP_CAPABILITIES is per-CPU scope according
to Intel Software Developer Manual.

The turbo max freq is already per-CPU in current code, so make
similar change to the max non-turbo frequency as well.

Reported-by: Wendy Wang <wendy.wang@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw: Subject and changelog edits ]
Cc: 4.18+ <stable@vger.kernel.org> # 4.18+: a45ee4d4e13b: cpufreq: intel_pstate: Change intel_pstate_get_hwp_max() argument
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Rename two functions

Rename intel_cpufreq_adjust_hwp() and intel_cpufreq_adjust_perf_ctl()
to intel_cpufreq_hwp_update() and intel_cpufreq_perf_ctl_update(),
respectively, to avoid possible confusion with the ->adjist_perf()
callback function, intel_cpufreq_adjust_perf().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>

cpufreq: intel_pstate: Change intel_pstate_get_hwp_max() argument

All of the callers of intel_pstate_get_hwp_max() access the struct
cpudata object that corresponds to the given CPU already and the
function itself needs to access that object (in order to update
hwp_cap_cached), so modify the code to pass a struct cpudata pointer
to it instead of the CPU number.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>

cpufreq: intel_pstate: Always read hwp_cap_cached with READ_ONCE()

Because intel_pstate_get_hwp_max() which updates hwp_cap_cached
may run in parallel with the readers of it, annotate all of the
read accesses to it with READ_ONCE().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>

cpufreq: intel_pstate: remove obsolete functions

percent_fp() was used in intel_pstate_pid_reset(), which was removed in
commit 9d0ef7af1f2d ("cpufreq: intel_pstate: Do not use PID-based P-state
selection") and hence, percent_fp() is unused since then.

percent_ext_fp() was last used in intel_pstate_update_perf_limits(), which
was refactored in commit 1a4fe38add8b ("cpufreq: intel_pstate: Remove
max/min fractions to limit performance"), and hence, percent_ext_fp() is
unused since then.

make CC=clang W=1 points us those unused functions:

drivers/cpufreq/intel_pstate.c:79:23: warning: unused function 'percent_fp' [-Wunused-function]
static inline int32_t percent_fp(int percent)
^

drivers/cpufreq/intel_pstate.c:94:23: warning: unused function 'percent_ext_fp' [-Wunused-function]
static inline int32_t percent_ext_fp(int percent)
^

Remove those obsolete functions.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use HWP capabilities in intel_cpufreq_adjust_perf()

If turbo P-states cannot be used, either due to the configuration of
the processor, or because intel_pstate is not allowed to used them,
the maximum available P-state with HWP enabled corresponds to the
HWP_CAP.GUARANTEED value which is not static. It can be adjusted by
an out-of-band agent or during an Intel Speed Select performance
level change, so long as it remains less than or equal to
HWP_CAP.MAX.

However, if turbo P-states cannot be used, intel_cpufreq_adjust_perf()
always uses pstate.max_pstate (set during the initialization of the
driver only) as the maximum available P-state, so it may miss a change
of the HWP_CAP.GUARANTEED value.

Prevent that from happening by modifyig intel_cpufreq_adjust_perf()
to always read the "guaranteed" and "maximum turbo" performance
levels from the cached HWP_CAP value.

Fixes: a365ab6b9dfb ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Fix fast-switch fallback path

When sugov_update_single_perf() falls back to the "frequency"
path due to the missing scale-invariance, it will call
cpufreq_driver_fast_switch() via sugov_fast_switch()
and the driver's ->fast_switch() callback will be invoked,
so it must not be NULL.

However, after commit a365ab6b9dfb ("cpufreq: intel_pstate: Implement
the ->adjust_perf() callback") intel_pstate sets ->fast_switch() to
NULL when it is going to use intel_cpufreq_adjust_perf(), which is a
mistake, because on x86 the scale-invariance may be turned off
dynamically, so modify it to retain the original ->adjust_perf()
callback pointer.

Fixes: a365ab6b9dfb ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback")
Reported-by: Kenneth R. Crudup <kenny@panix.com>
Tested-by: Kenneth R. Crudup <kenny@panix.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use most recent guaranteed performance values

When turbo has been disabled by the BIOS, but HWP_CAP.GUARANTEED is
changed later, user space may want to take advantage of this increased
guaranteed performance.

HWP_CAP.GUARANTEED is not a static value. It can be adjusted by an
out-of-band agent or during an Intel Speed Select performance level
change. The HWP_CAP.MAX is still the maximum achievable performance
with turbo disabled by the BIOS, so HWP_CAP.GUARANTEED can still
change as long as it remains less than or equal to HWP_CAP.MAX.

When HWP_CAP.GUARANTEED is changed, the sysfs base_frequency
attribute shows the most recent guaranteed frequency value. This
attribute can be used by user space software to update the scaling
min/max limits of the CPU.

Currently, the ->setpolicy() callback already uses the latest
HWP_CAP values when setting HWP_REQ, but the ->verify() callback will
restrict the user settings to the to old guaranteed performance value
which prevents user space from making use of the extra CPU capacity
theoretically available to it after increasing HWP_CAP.GUARANTEED.

To address this, read HWP_CAP in intel_pstate_verify_cpu_policy()
to obtain the maximum P-state that can be used and use that to
confine the policy max limit instead of using the cached and
possibly stale pstate.max_freq value for this purpose.

For consistency, update intel_pstate_update_perf_limits() to use the
maximum available P-state returned by intel_pstate_get_hwp_max() to
compute the maximum frequency instead of using the return value of
intel_pstate_get_max_freq() which, again, may be stale.

This issue is a side-effect of fixing the scaling frequency limits in
commit eacc9c5a927e ("cpufreq: intel_pstate: Fix intel_pstate_get_hwp_max()
for turbo disabled") which corrected the setting of the reduced scaling
frequency values, but caused stale HWP_CAP.GUARANTEED to be used in
the case at hand.

Fixes: eacc9c5a927e ("cpufreq: intel_pstate: Fix intel_pstate_get_hwp_max() for turbo disabled")
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 5.8+ <stable@vger.kernel.org> # 5.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Implement the ->adjust_perf() callback

Make intel_pstate expose the ->adjust_perf() callback when it
operates in the passive mode with HWP enabled which causes the
schedutil governor to use that callback instead of ->fast_switch().

The minimum and target performance-level values passed by the
governor to ->adjust_perf() are converted to HWP.REQ.MIN and
HWP.REQ.DESIRED, respectively, which allows the processor to
adjust its configuration to maximize energy-efficiency while
providing sufficient capacity.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: intel_pstate: Simplify intel_cpufreq_update_pstate()

Avoid doing the same assignment in both branches of a conditional,
do it after the whole conditional instead.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Take CPUFREQ_GOV_STRICT_TARGET into account

Make intel_pstate take the new CPUFREQ_GOV_STRICT_TARGET governor
flag into account when it operates in the passive mode with HWP
enabled, so as to fix the "powersave" governor behavior in that
case (currently, HWP is allowed to scale the performance all the
way up to the policy max limit when the "powersave" governor is
used, but it should be constrained to the policy min limit then).

Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: 9a2a9ebc0a75 cpufreq: Introduce governor flags
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: 218f66870181 cpufreq: Introduce CPUFREQ_GOV_STRICT_TARGET
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: ea9364bbadf1 cpufreq: Add strict_target to struct cpufreq_policy

cpufreq: intel_pstate: Avoid missing HWP max updates in passive mode

If the cpufreq policy max limit is changed when intel_pstate operates
in the passive mode with HWP enabled and the "powersave" governor is
used on top of it, the HWP max limit is not updated as appropriate.

Namely, in the "powersave" governor case, the target P-state
is always equal to the policy min limit, so if the latter does
not change, intel_cpufreq_adjust_hwp() is not invoked to update
the HWP Request MSR due to the "target_pstate != old_pstate" check
in intel_cpufreq_update_pstate(), so the HWP max limit is not
updated as a result.

Also, if the CPUFREQ_NEED_UPDATE_LIMITS flag is not set for the
driver and the target frequency does not change along with the
policy max limit, the "target_freq == policy->cur" check in
__cpufreq_driver_target() prevents the driver's ->target() callback
from being invoked at all, so the HWP max limit is not updated.

To prevent that occurring, set the CPUFREQ_NEED_UPDATE_LIMITS flag
in the intel_cpufreq driver structure if HWP is enabled and modify
intel_cpufreq_update_pstate() to do the "target_pstate != old_pstate"
check only in the non-HWP case and let intel_cpufreq_adjust_hwp()
always run in the HWP case (it will update HWP Request only if the
cached value of the register is different from the new one including
the limits, so if neither the target P-state value nor the max limit
changes, the register write will still be avoided).

Fixes: f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled")
Reported-by: Zhang Rui <rui.zhang@intel.com>
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: 1c534352f47f cpufreq: Introduce CPUFREQ_NEED_UPDATE_LIMITS ...
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>

cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver

There is a corner case that if the intel_pstate driver fails to be
registered (might be due to invalid MSR access) and acpi_cpufreq
takse over, the intel_pstate sysfs interface is still populated
which may confuse user space (turbostat for example):

grep . /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
acpi-cpufreq

grep . /sys/devices/system/cpu/intel_pstate/*
/sys/devices/system/cpu/intel_pstate/max_perf_pct:0
/sys/devices/system/cpu/intel_pstate/min_perf_pct:0
grep: /sys/devices/system/cpu/intel_pstate/no_turbo: Resource temporarily unavailable
grep: /sys/devices/system/cpu/intel_pstate/num_pstates: Resource temporarily unavailable
/sys/devices/system/cpu/intel_pstate/status:off
grep: /sys/devices/system/cpu/intel_pstate/turbo_pct: Resource temporarily unavailable

The mere presence of the intel_pstate sysfs interface does not mean
that intel_pstate is in use (for example, echo "off" to "status"),
but it should not be created in the failing case.

Fix this issue by deleting the intel_pstate sysfs if the driver
registration fails.

Reported-by: Wendy Wang <wendy.wang@intel.com>
Suggested-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com
[ rjw: Refactor code to avoid jumps, change function name, changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix missing return statement

Fix missing return statement when writing "off" to intel_pstate status
sysfs I/F.

Fixes: 55671ea3257a ("cpufreq: intel_pstate: Free memory only when turning off")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix intel_pstate_get_hwp_max() for turbo disabled

This fixes the behavior of the scaling_max_freq and scaling_min_freq
sysfs files in systems which had turbo disabled by the BIOS.

Caleb noticed that the HWP is programmed to operate in the wrong
P-state range on his system when the CPUFREQ policy min/max frequency
is set via sysfs. This seems to be because in his system
intel_pstate_get_hwp_max() is returning the maximum turbo P-state even
though turbo was disabled by the BIOS, which causes intel_pstate to
scale kHz frequencies incorrectly e.g. setting the maximum turbo
frequency whenever the maximum guaranteed frequency is requested via
sysfs.

Tested-by: Caleb Callaway <caleb.callaway@intel.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Minor subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Free memory only when turning off

When intel_pstate switches the operation mode from "active" to
"passive" or the other way around, freeing its data structures
representing CPUs and allocating them again from scratch is not
necessary and wasteful. Moreover, if these data structures are
preserved, the cached HWP Request MSR value from there may be
written to the MSR to start with to reinitialize it and help to
restore the EPP value set previously (it is set to 0xFF when CPUs
go offline to allow their SMT siblings to use the full range of
EPP values and that also happens when the driver gets unregistered).

Accordingly, modify the driver to only do a full cleanup on driver
object registration errors and when its status is changed to "off"
via sysfs and to write the cached HWP Request MSR value back to
the MSR on CPU init if the data structure representing the given
CPU is still there.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Add ->offline and ->online callbacks

Add ->offline and ->online driver callbacks to prepare for taking a
CPU offline and to restore its working configuration when it goes
back online, respectively, to avoid invoking the ->init callback on
every CPU online which is quite a bit of unnecessary overhead.

Define ->offline and ->online so that they can be used in the
passive mode as well as in the active mode and because ->offline
will do the majority of ->stop_cpu work, the passive mode does
not need that callback any more, so drop it from there.

Also modify the active mode ->suspend and ->resume callbacks to
prevent them from interfering with the new ->offline and ->online
ones in case the latter are invoked withing the system-wide suspend
and resume code flow and make the passive mode use them too.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Tweak the EPP sysfs interface

Modify the EPP sysfs interface to reject attempts to change the EPP
to values different from 0 ("performance") in the active mode with
the "performance" policy (ie. scaling_governor set to "performance"),
to avoid situations in which the kernel appears to discard data
passed to it via the EPP sysfs attribute.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Update cached EPP in the active mode

Make intel_pstate update the cached EPP value when setting the EPP
via sysfs in the active mode just like it is the case in the passive
mode, for consistency, but also for the benefit of subsequent
changes.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Refuse to turn off with HWP enabled

After commit f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive
mode with HWP enabled") it is possible to change the driver status
to "off" via sysfs with HWP enabled, which effectively causes the
driver to unregister itself, but HWP remains active and it forces the
minimum performance, so even if another cpufreq driver is loaded,
it will not be able to control the CPU frequency.

For this reason, make the driver refuse to change the status to
"off" with HWP enabled.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

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>

cpufreq: intel_pstate: Fix cpuinfo_max_freq when MSR_TURBO_RATIO_LIMIT is 0

The MSR_TURBO_RATIO_LIMIT can be 0. This is not an error. User can update
this MSR via BIOS settings on some systems or can use msr tools to update.
Also some systems boot with value = 0.

This results in display of cpufreq/cpuinfo_max_freq wrong. This value
will be equal to cpufreq/base_frequency, even though turbo is enabled.

But platform will still function normally in HWP mode as we get max
1-core frequency from the MSR_HWP_CAPABILITIES. This MSR is already used
to calculate cpu->pstate.turbo_freq, which is used for to set
policy->cpuinfo.max_freq. But some other places cpu->pstate.turbo_pstate
is used. For example to set policy->max.

To fix this, also update cpu->pstate.turbo_pstate when updating
cpu->pstate.turbo_freq.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix EPP setting via sysfs in active mode

Because intel_pstate_set_energy_pref_index() reads and writes the
MSR_HWP_REQUEST register without using the cached value of it used by
intel_pstate_hwp_boost_up() and intel_pstate_hwp_boost_down(), those
functions may overwrite the value written by it and so the EPP value
set via sysfs may be lost.

To avoid that, make intel_pstate_set_energy_pref_index() take the
cached value of MSR_HWP_REQUEST just like the other two routines
mentioned above and update it with the new EPP value coming from
user space in addition to updating the MSR.

Note that the MSR itself still needs to be updated too in case
hwp_boost is unset or the boosting mechanism is not active at the
EPP change time.

Fixes: e0efd5be63e8 ("cpufreq: intel_pstate: Add HWP boost utility and sched util hooks")
Reported-by: Francisco Jerez <currojerez@riseup.net>
Cc: 4.18+ <stable@vger.kernel.org> # 4.18+: 3da97d4db8ee cpufreq: intel_pstate: Rearrange ...
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>

cpufreq: intel_pstate: Rearrange the storing of new EPP values

Move the locking away from intel_pstate_set_energy_pref_index()
into its only caller and drop the (now redundant) return_pref label
from it.

Also move the "raw" EPP value check into the caller of that function,
so as to do it before acquiring the mutex, and reduce code duplication
related to the "raw" EPP values processing somewhat.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>

cpufreq: intel_pstate: Avoid enabling HWP if EPP is not supported

Although there are processors supporting hardware-managed P-states
(HWP) without the energy-performance preference (EPP) feature, they
are not expected to be run with HWP enabled (the BIOS should disable
HWP on those systems). Missing EPP support generally indicates an
incomplete HWP implementation and so it is better to avoid using
HWP on those systems in production.

However, intel_pstate currently enables HWP on such systems, which
is questionable, so prevent it from doing that by making it check
EPP support before enabling HWP and avoid enabling it if EPP is not
supported by the processor at hand.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Clean up aperf_mperf_shift description

The kerneldoc description of the aperf_mperf_shift field in
struct global_params is unclear and there is a typo in it, so
simplify it and clean it up.

Reported-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lee Jones <lee.jones@linaro.org>

cpufreq: intel_pstate: Supply struct attribute description for get_aperf_mperf_shift()

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

drivers/cpufreq/intel_pstate.c:293: warning: Function parameter or member 'get_aperf_mperf_shift' not described in 'pstate_funcs'

Suggested-by: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Remove line break ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix active mode setting from command line

If intel_pstate starts in the passive mode by default (that happens
when the processor in the system doesn't support HWP), passing
intel_pstate=active in the kernel command line doesn't work, so
fix that.

Fixes: 33aa46f252c7 ("cpufreq: intel_pstate: Use passive mode by default without HWP")
Reported-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Doug Smythies <dsmythies@telus.net>

cpufreq: intel_pstate: Fix static checker warning for epp variable

Fix warning for:
drivers/cpufreq/intel_pstate.c:731 store_energy_performance_preference()
error: uninitialized symbol 'epp'.

This warning is for a case, when energy_performance_preference attribute
matches pre defined strings. In this case the value of raw epp will not
be used to set EPP bits in MSR_HWP_REQUEST. So initializing with any
value is fine.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Allow raw energy performance preference value

Currently using attribute "energy_performance_preference", user space can
write one of the four per-defined preference string. These preference
strings gets mapped to a hard-coded Energy-Performance Preference (EPP) or
Energy-Performance Bias (EPB) knob.

These four values are supposed to cover broad spectrum of use cases, but
are not uniformly distributed in the range. There are number of cases,
where this is not enough. For example:

Suppose user wants more performance when connected to AC. Instead of using
default "balance performance", the "performance" setting can be used. This
changes EPP value from 0x80 to 0x00. But setting EPP to 0, results in
electrical and thermal issues on some platforms. This results in
aggressive throttling, which causes a drop in performance. But some value
between 0x80 and 0x00 results in better performance. But that value can't
be fixed as the power curve is not linear. In some cases just changing EPP
from 0x80 to 0x75 is enough to get significant performance gain.

Similarly on battery the default "balance_performance" mode can be
aggressive in power consumption. But picking up the next choice
"balance power" results in too much loss of performance, which results in
bad user experience in use cases like "Google Hangout". It was observed
that some value between these two EPP is optimal.

This change allows fine grain EPP tuning for platform like Chromebook or
for users who wants to fine tune power and performance.
Here based on the product and use cases, different EPP values can be set.
This change is similar to the change done for:
/sys/devices/system/cpu/cpu*/power/energy_perf_bias
where user has choice to write a predefined string or raw value.

The change itself is trivial. When user preference doesn't match
predefined string preferences and value is an unsigned integer and in
range, use that value for EPP. When the EPP feature is not present
writing raw value is not supported.

Suggested-by: Len Brown <lenb@kernel.org>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Allow enable/disable energy efficiency

By default intel_pstate the driver disables energy efficiency by setting
MSR_IA32_POWER_CTL bit 19 for Kaby Lake desktop CPU model in HWP mode.
This CPU model is also shared by Coffee Lake desktop CPUs. This allows
these systems to reach maximum possible frequency. But this adds power
penalty, which some customers don't want. They want some way to enable/
disable dynamically.

So, add an additional attribute "energy_efficiency" under
/sys/devices/system/cpu/intel_pstate/ for these CPU models. This allows
to read and write bit 19 ("Disable Energy Efficiency Optimization") in
the MSR IA32_POWER_CTL.

This attribute is present in both HWP and non-HWP mode as this has an
effect in both modes. Refer to Intel Software Developer's manual for
details.

The scope of this bit is package wide. Also these systems are single
package systems. So read/write MSR on the current CPU is enough.

The energy efficiency (EE) bit setting needs to be preserved during
suspend/resume and CPU offline/online operation. To do this:
- Restoring the EE setting from the cpufreq resume() callback, if there
is change from the system default.
- By default, don't disable EE from cpufreq init() callback for matching
CPU models. Since the scope is package wide and is a single package
system, move the disable EE calls from init() callback to
intel_pstate_init() function, which is called only once.

Suggested-by: Len Brown <lenb@kernel.org>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add one more OOB control bit

Add one more bit for OOB (Out Of Band) enabling of P-states.

If OOB handling of P-states is enabled, intel_pstate shouldn't load.
Currently, only "BIT(8) == 1" of the MSR MSR_MISC_PWR_MGMT is
considered as OOB, but "BIT(18) == 1" needs to be taken into
consideration as OOB condition too.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Add an empty code line, edit subject and changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Only mention the BIOS disabling turbo mode once

Make a note of the first time we discover the turbo mode has been
disabled by the BIOS, as otherwise we complain every time we try to
update the mode.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use passive mode by default without HWP

After recent changes allowing scale-invariant utilization to be
used on x86, the schedutil governor on top of intel_pstate in the
passive mode should be on par with (or better than) the active mode
"powersave" algorithm of intel_pstate on systems in which
hardware-managed P-states (HWP) are not used, so it should not be
necessary to use the internal scaling algorithm in those cases.

Accordingly, modify intel_pstate to start in the passive mode by
default if the processor at hand does not support HWP of if the driver
is requested to avoid using HWP through the kernel command line.

Among other things, that will allow utilization clamps and the
support for RT/DL tasks in the schedutil governor to be utilized on
systems in which intel_pstate is used.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Simplify intel_pstate_cpu_init()

The initial policy value set by intel_pstate_cpu_init() depends on
whether or not CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is set, but
that is not necessary, because the core will set the policy to
"performance" in cpufreq_init_policy() if the default governor is
"performance" anyway.

Accordingly, change intel_pstate_cpu_init() to always set policy
to CPUFREQ_POLICY_POWERSAVE initially to provide a valid fallback
value to cpufreq_init_policy() in case the default cpufreq governor
is neither "powersave" nor "performance".

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq/intel_pstate: Fix wrong macro conversion

The feature flag hwp_support_ids are supposed to match on is
X86_FEATURE_HWP, not X86_FEATURE_APERFMPERF. Fix it.

[ bp: Write commit message. ]

Fixes: b11d77fa300d ("cpufreq: Convert to new X86 CPU match macros")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200324060124.GC11705@shao2-debian

cpufreq: Convert to new X86 CPU match macros

The new macro set has a consistent namespace and uses C99 initializers
instead of the grufty C89 ones.

Get rid the of most local macro wrappers for consistency. The ones which
make sense for readability are renamed to X86_MATCH*.

In the centrino driver this also removes the two extra duplicates of family
6 model 13 which have no value at all.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/87eetheu88.fsf@nanos.tec.linutronix.de

cpufreq: intel_pstate: Consolidate policy verification

There is still some code duplication between intel_pstate_verify_policy()
and intel_cpufreq_verify_policy(), so avoid it by moving the common
code into a separate function and calling it from both these places.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

x86/intel_pstate: Handle runtime turbo disablement/enablement in frequency invariance

On some platforms such as the Dell XPS 13 laptop the firmware disables turbo
when the machine is disconnected from AC, and viceversa it enables it again
when it's reconnected. In these cases a _PPC ACPI notification is issued.

The scheduler needs to know freq_max for frequency-invariant calculations.
To account for turbo availability to come and go, record freq_max at boot as
if turbo was available and store it in a helper variable. Use a setter
function to swap between freq_base and freq_max every time turbo goes off or on.

Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20200122151617.531-7-ggherdovich@suse.cz

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: 3000ce3c52f8 ("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>

cpufreq: intel_pstate: fix spelling mistake: "Whethet" -> "Whether"

Fix a spelling typo in the comment, no function change.

Signed-off-by: Harry Pan <harry.pan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix invalid EPB setting

The max value of EPB can only be 0x0F. Attempting to set more than that
triggers an "unchecked MSR access error" warning which happens in
intel_pstate_hwp_force_min_perf() called via cpufreq stop_cpu().

However, it is not even necessary to touch the EPB from intel_pstate,
because it is restored on every CPU online by the intel_epb.c code,
so let that code do the right thing and drop the redundant (and
incorrect) EPB update from intel_pstate.

Fixes: af3b7379e2d70 ("cpufreq: intel_pstate: Force HWP min perf before offline")
Reported-by: Qian Cai <cai@lca.pw>
Cc: 5.2+ <stable@vger.kernel.org> # 5.2+
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix plain int as pointer warning from sparse

Fix sparse warning: Using plain integer as NULL pointer.

Replace assignment of 0 to pointers with NULL assignment.

Signed-off-by: Jamal Shareef <jamal.k.shareef@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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: 67d874c3b2c6 ("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>

x86/intel: Aggregate microserver naming

Currently big microservers have _XEON_D while small microservers have
_X, Make it uniformly: _D.

for i in `git grep -l "\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*_\(X\|XEON_D\)"`
do
sed -i -e 's/\(\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*ATOM.*\)_X/\1_D/g' \
-e 's/\(\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*\)_XEON_D/\1_D/g' ${i}
done

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: x86@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20190827195122.677152989@infradead.org

x86/intel: Aggregate big core graphics naming

Currently big core clients with extra graphics on have:

- _G
- _GT3E

Make it uniformly: _G

for i in `git grep -l "\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*_GT3E"`
do
sed -i -e 's/\(\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*\)_GT3E/\1_G/g' ${i}
done

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: x86@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20190827195122.622802314@infradead.org

x86/intel: Aggregate big core mobile naming

Currently big core mobile chips have either:

- _L
- _ULT
- _MOBILE

Make it uniformly: _L.

for i in `git grep -l "\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*_\(MOBILE\|ULT\)"`
do
sed -i -e 's/\(\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*\)_\(MOBILE\|ULT\)/\1_L/g' ${i}
done

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: x86@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190827195122.568978530@infradead.org

x86/intel: Aggregate big core client naming

Currently the big core client models either have:

- no OPTDIFF
- _CORE
- _DESKTOP

Make it uniformly: 'no OPTDIFF'.

for i in `git grep -l "\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*_\(CORE\|DESKTOP\)"`
do
sed -i -e 's/\(\(INTEL_FAM6_\|VULNWL_INTEL\|INTEL_CPU_FAM6\).*\)_\(CORE\|DESKTOP\)/\1/g' ${i}
done

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: x86@kernel.org
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190827195122.513945586@infradead.org

cpufreq: intel_pstate: Implement QoS supported freq constraints

Intel pstate driver exposes min_perf_pct and max_perf_pct sysfs files,
which can be used to force a limit on the min/max P state of the driver.
Though these files eventually control the min/max frequencies that the
CPUs will run at, they don't make a change to policy->min/max values.

When the values of these files are changed (in passive mode of the
driver), it leads to calling ->limits() callback of the cpufreq
governors, like schedutil. On a call to it the governors shall
forcefully update the frequency to come within the limits. Since the
limits, i.e. policy->min/max, aren't updated by the driver, the
governors fails to get the target freq within limit and sometimes aborts
the update believing that the frequency is already set to the target
value.

This patch implements the QoS supported frequency constraints to update
policy->min/max values whenever min_perf_pct or max_perf_pct files are
updated. This is only done for the passive mode as of now, as the driver
is already working fine in active mode.

Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX")
Reported-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

Based on 1 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 as published by
the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/cpufreq: Convert some slow-path static_cpu_has() callers to boot_cpu_has()

Using static_cpu_has() is pointless on those paths, convert them to the
boot_cpu_has() variant.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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>

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>

cpufreq/intel_pstate: Load only on Intel hardware

This driver is Intel-only so loading on anything which is not Intel is
pointless. Prevent it from doing so.

While at it, correct the "not supported" print statement to say CPU
"model" which is what that test does.

Fixes: 076b862c7e44 (cpufreq: intel_pstate: Add reasons for failure and debug messages)
Suggested-by: Erwan Velu <e.velu@criteo.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Also use CPPC nominal_perf for base_frequency

The ACPI specification states that if the "Guaranteed Performance
Register" is not implemented, the OSPM assumes guaranteed performance
to always be equal to nominal performance.

So for invalid or unimplemented guaranteed performance register, use
nominal performance as guaranteed performance.

This change will fall back to nominal_perf when guranteed_perf is
invalid. If nominal_perf is also invalid or not present, fall back
to the existing implementation, which is to read from HWP Capabilities
MSR.

Fixes: 86d333a8cc7f ("cpufreq: intel_pstate: Add base_frequency attribute")
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix up iowait_boost computation

After commit b8bd1581aa61 ("cpufreq: intel_pstate: Rework iowait
boosting to be less aggressive") the handling of the case when
the SCHED_CPUFREQ_IOWAIT flag is set again after a few iterations of
intel_pstate_update_util() is a bit inconsistent, because the
new value of cpu->iowait_boost may be lower than ONE_EIGHTH_FP
if it was set before, but has not dropped down to zero just yet.

Fix that up by ensuring that the new value of cpu->iowait_boost
will always be at least ONE_EIGHTH_FP then.

Fixes: b8bd1581aa61 ("cpufreq: intel_pstate: Rework iowait boosting to be less aggressive")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Rework iowait boosting to be less aggressive

The current iowait boosting mechanism in intel_pstate_update_util()
is quite aggressive, as it goes to the maximum P-state right away,
and may cause excessive amounts of energy to be used, which is not
desirable and arguably isn't necessary too.

Follow commit a5a0809bc58e ("cpufreq: schedutil: Make iowait boost
more energy efficient") that reworked the analogous iowait boost
mechanism in the schedutil governor and make the iowait boosting
in intel_pstate_update_util() work along the same lines.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Eliminate intel_pstate_get_base_pstate()

There is only one caller of intel_pstate_get_base_pstate() and it is
more straightforward to carry out the computation directly in the
caller, so do that and drop intel_pstate_get_base_pstate().

No intentional changes of behavior.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Avoid redundant initialization of local vars

After commit 1a4fe38add8b ("cpufreq: intel_pstate: Remove max/min
fractions to limit performance") the initial value of the pstate local
variable in intel_pstate_max_within_limits() and the initial value of
the max_pstate local variable in intel_pstate_prepare_request() are
both immediately discarded, so initialize both these variables to
their target values upfront.

No intentional changes of behavior.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add reasons for failure and debug messages

The init code path has several exceptions where the driver can
decide not to load.

As CONFIG_X86_INTEL_PSTATE is generally set to Y, the return code is
not reachable. The initialization code is neither verbose of the
reason why it did choose to prematurely exit, so it is difficult for
a user to determine, on a given platform, why the driver didn't load
properly.

This patch is about reporting to the user the reason/context of why
the driver failed to load. That is a precious hint when debugging
a platform.

Signed-off-by: Erwan Velu <e.velu@criteo.com>
[ rjw: Subject & changelog, minor fixups ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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>

cpufreq: intel_pstate: Force HWP min perf before offline

Force HWP Request MAX = HWP Request MIN = HWP Capability MIN and EPP to
0xFF. In this way the performance limits on the offlined CPU will not
influence performance limits on its sibling CPU, which is still online.

If the sibling CPU is calling for higher performance, it will impact the
max core performance. Here core performance will follow higher of the
performance requests from each sibling.

Reported-and-tested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq/intel_pstate: Replace synchronize_sched() with synchronize_rcu()

Now that synchronize_rcu() waits for preempt-disable regions of code
as well as RCU read-side critical sections, synchronize_sched() can be
replaced by synchronize_rcu(). This commit therefore makes this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: <linux-pm@vger.kernel.org>

cpufreq: intel_pstate: Fix compilation for !CONFIG_ACPI

While at it, add a few comments which config options #ifdef
and #else statements refer to.

Fixes: 86d333a8cc7f (cpufreq: intel_pstate: Add base_frequency attribute)
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add base_frequency attribute

Expose base_frequency to user space via cpufreq sysfs when HWP is in
use.

This HWP base frequency is read from the ACPI _CPC object if present,
or from the HWP Capabilities MSR otherwise.

On the majority of the HWP platforms the _CPC object will point to
the HWP Capabilities MSR using the "Functional Fixed Hardware"
address space type. The address space type also can simply be
ACPI_TYPE_INTEGER, however, in which case the platform firmware
can set its value at the initialization time based on the system
constraints.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

x86/cpu: Sanitize FAM6_ATOM naming

Going primarily by:

https://en.wikipedia.org/wiki/List_of_Intel_Atom_microprocessors

with additional information gleaned from other related pages; notably:

- Bonnell shrink was called Saltwell
- Moorefield is the Merriefield refresh which makes it Airmont

The general naming scheme is: FAM6_ATOM_UARCH_SOCTYPE

for i in `git grep -l FAM6_ATOM` ; do
sed -i -e 's/ATOM_PINEVIEW/ATOM_BONNELL/g' \
-e 's/ATOM_LINCROFT/ATOM_BONNELL_MID/' \
-e 's/ATOM_PENWELL/ATOM_SALTWELL_MID/g' \
-e 's/ATOM_CLOVERVIEW/ATOM_SALTWELL_TABLET/g' \
-e 's/ATOM_CEDARVIEW/ATOM_SALTWELL/g' \
-e 's/ATOM_SILVERMONT1/ATOM_SILVERMONT/g' \
-e 's/ATOM_SILVERMONT2/ATOM_SILVERMONT_X/g' \
-e 's/ATOM_MERRIFIELD/ATOM_SILVERMONT_MID/g' \
-e 's/ATOM_MOOREFIELD/ATOM_AIRMONT_MID/g' \
-e 's/ATOM_DENVERTON/ATOM_GOLDMONT_X/g' \
-e 's/ATOM_GEMINI_LAKE/ATOM_GOLDMONT_PLUS/g' ${i}
done

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: dave.hansen@linux.intel.com
Cc: len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

cpufreq: intel_pstate: Ignore turbo active ratio in HWP

When HWP is active turbo active ratio is not used, so we should allow
policy max frequency above turbo activation ratio to be set. When HWP is
not active, then any policy max frequency above turbo activation ratio
can result upto max one-core turbo frequency.

This fix helps better thermal control in turbo region when other methods
like "Running Average Power Limit" is not available to use.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Limit the scope of HWP dynamic boost platforms

Dynamic boosting of HWP performance on IO wake showed significant
improvement to IO workloads. This series was intended for Skylake Xeon
platforms only and feature was enabled by default based on CPU model
number.

But some Xeon platforms reused the Skylake desktop CPU model number. This
caused some undesirable side effects to some graphics workloads. Since
they are heavily IO bound, the increase in CPU performance decreased the
power available for GPU to do its computing and hence decrease in graphics
benchmark performance.

For example on a Skylake desktop, GpuTest benchmark showed average FPS
reduction from 529 to 506.

This change makes sure that HWP boost feature is only enabled for Skylake
server platforms by using ACPI FADT preferred PM Profile. If some desktop
users wants to get benefit of boost, they can still enable boost from
intel_pstate sysfs attribute "hwp_dynamic_boost".

Fixes: 41ab43c9c89e (cpufreq: intel_pstate: enable boost for Skylake Xeon)
Link: https://bugs.freedesktop.org/show_bug.cgi?id=107410
Reported-by: Eero Tamminen <eero.t.tamminen@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Show different max frequency with turbo 3 and HWP

On HWP platforms with Turbo 3.0, the HWP capability max ratio shows the
maximum ratio of that core, which can be different than other cores. If
we show the correct maximum frequency in cpufreq sysfs via
cpuinfo_max_freq and scaling_max_freq then, user can know which cores
can run faster for pinning some high priority tasks.

Currently the max turbo frequency is shown as max frequency, which is
the max of all cores, even if some cores can't reach that frequency
even for single threaded workload.

But it is possible that max ratio in HWP capabilities is set as 0xFF or
some high invalid value (E.g. One KBL NUC). Since the actual performance
can never exceed 1 core turbo frequency from MSR TURBO_RATIO_LIMIT, we
use this as a bound check.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Register when ACPI PCCH is present

Currently, intel_pstate doesn't register if _PSS is not present on
HP Proliant systems, because it expects the firmware to take over
CPU performance scaling in that case. However, if ACPI PCCH is
present, the firmware expects the kernel to use it for CPU
performance scaling and the pcc-cpufreq driver is loaded for that.

Unfortunately, the firmware interface used by that driver is not
scalable for fundamental reasons, so pcc-cpufreq is way suboptimal
on systems with more than just a few CPUs. In fact, it is better to
avoid using it at all.

For this reason, modify intel_pstate to look for ACPI PCCH if _PSS
is not present and register if it is there. Also prevent the
pcc-cpufreq driver from trying to initialize itself if intel_pstate
has been registered already.

Fixes: fbbcdc0744da (intel_pstate: skip the driver if ACPI has power mgmt option)
Reported-by: Andreas Herrmann <aherrmann@suse.com>
Reviewed-by: Andreas Herrmann <aherrmann@suse.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Andreas Herrmann <aherrmann@suse.com>
Cc: 4.16+ <stable@vger.kernel.org> # 4.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: use match_string() helper

match_string() returns the index of an array for a matching string,
which can be used instead of open coded variant.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix scaling max/min limits with Turbo 3.0

When scaling max/min settings are changed, internally they are converted
to a ratio using the max turbo 1 core turbo frequency. This works fine
when 1 core max is same irrespective of the core. But under Turbo 3.0,
this will not be the case. For example:
Core 0: max turbo pstate: 43 (4.3GHz)
Core 1: max turbo pstate: 45 (4.5GHz)
In this case 1 core turbo ratio will be maximum of all, so it will be
45 (4.5GHz). Suppose scaling max is set to 4GHz (ratio 40) for all cores
,then on core one it will be
= max_state * policy->max / max_freq;
= 43 * (4000000/4500000) = 38 (3.8GHz)
= 38
which is 200MHz less than the desired.
On core2, it will be correctly set to ratio 40 (4GHz). Same holds true
for scaling min frequency limit. So this requires usage of correct turbo
max frequency for core one, which in this case is 4.3GHz. So we need to
adjust per CPU cpu->pstate.turbo_freq using the maximum HWP ratio of that
core.

This change uses the HWP capability of a core to adjust max turbo
frequency. But since Broadwell HWP doesn't use ratios in the HWP
capabilities, we have to use legacy max 1 core turbo ratio. This is not
a problem as the HWP capabilities don't differ among cores in Broadwell.
We need to check for non Broadwell CPU model for applying this change,
though.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 4.6+ <stable@vger.kernel.org> # 4.6+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

treewide: Use array_size() in vzalloc()

The vzalloc() function has no 2-factor argument form, so multiplication
factors need to be wrapped in array_size(). This patch replaces cases of:

vzalloc(a * b)

with:
vzalloc(array_size(a, b))

as well as handling cases of:

vzalloc(a * b * c)

with:

vzalloc(array3_size(a, b, c))

This does, however, attempt to ignore constant size factors like:

vzalloc(4 * 1024)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
vzalloc(
- (sizeof(TYPE)) * E
+ sizeof(TYPE) * E
, ...)
|
vzalloc(
- (sizeof(THING)) * E
+ sizeof(THING) * E
, ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
vzalloc(
- sizeof(u8) * (COUNT)
+ COUNT
, ...)
|
vzalloc(
- sizeof(__u8) * (COUNT)
+ COUNT
, ...)
|
vzalloc(
- sizeof(char) * (COUNT)
+ COUNT
, ...)
|
vzalloc(
- sizeof(unsigned char) * (COUNT)
+ COUNT
, ...)
|
vzalloc(
- sizeof(u8) * COUNT
+ COUNT
, ...)
|
vzalloc(
- sizeof(__u8) * COUNT
+ COUNT
, ...)
|
vzalloc(
- sizeof(char) * COUNT
+ COUNT
, ...)
|
vzalloc(
- sizeof(unsigned char) * COUNT
+ COUNT
, ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
vzalloc(
- sizeof(TYPE) * (COUNT_ID)
+ array_size(COUNT_ID, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(TYPE) * COUNT_ID
+ array_size(COUNT_ID, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(TYPE) * (COUNT_CONST)
+ array_size(COUNT_CONST, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(TYPE) * COUNT_CONST
+ array_size(COUNT_CONST, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(THING) * (COUNT_ID)
+ array_size(COUNT_ID, sizeof(THING))
, ...)
|
vzalloc(
- sizeof(THING) * COUNT_ID
+ array_size(COUNT_ID, sizeof(THING))
, ...)
|
vzalloc(
- sizeof(THING) * (COUNT_CONST)
+ array_size(COUNT_CONST, sizeof(THING))
, ...)
|
vzalloc(
- sizeof(THING) * COUNT_CONST
+ array_size(COUNT_CONST, sizeof(THING))
, ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

vzalloc(
- SIZE * COUNT
+ array_size(COUNT, SIZE)
, ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
vzalloc(
- sizeof(TYPE) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(TYPE) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(TYPE) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(TYPE) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(TYPE))
, ...)
|
vzalloc(
- sizeof(THING) * (COUNT) * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vzalloc(
- sizeof(THING) * (COUNT) * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vzalloc(
- sizeof(THING) * COUNT * (STRIDE)
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
|
vzalloc(
- sizeof(THING) * COUNT * STRIDE
+ array3_size(COUNT, STRIDE, sizeof(THING))
, ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
vzalloc(
- sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
vzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
, ...)
|
vzalloc(
- sizeof(THING1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
vzalloc(
- sizeof(THING1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(THING1), sizeof(THING2))
, ...)
|
vzalloc(
- sizeof(TYPE1) * sizeof(THING2) * COUNT
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
|
vzalloc(
- sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+ array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
, ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
vzalloc(
- (COUNT) * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vzalloc(
- COUNT * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vzalloc(
- COUNT * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vzalloc(
- (COUNT) * (STRIDE) * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vzalloc(
- COUNT * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vzalloc(
- (COUNT) * STRIDE * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vzalloc(
- (COUNT) * (STRIDE) * (SIZE)
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
|
vzalloc(
- COUNT * STRIDE * SIZE
+ array3_size(COUNT, STRIDE, SIZE)
, ...)
)

// Any remaining multi-factor products, first at least 3-factor products
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
vzalloc(C1 * C2 * C3, ...)
|
vzalloc(
- E1 * E2 * E3
+ array3_size(E1, E2, E3)
, ...)
)

// And then all remaining 2 factors products when they're not all constants.
@@
expression E1, E2;
constant C1, C2;
@@

(
vzalloc(C1 * C2, ...)
|
vzalloc(
- E1 * E2
+ array_size(E1, E2)
, ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>

cpufreq: intel_pstate: enable boost for Skylake Xeon

Enable HWP boost on Skylake server and workstations.

Reported-by: Mel Gorman <mgorman@techsingularity.net>
Tested-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: New sysfs entry to control HWP boost

A new attribute is added to intel_pstate sysfs to enable/disable
HWP dynamic performance boost.

Reported-by: Mel Gorman <mgorman@techsingularity.net>
Tested-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: HWP boost performance on IO wakeup

This change uses SCHED_CPUFREQ_IOWAIT flag to boost HWP performance.
Since SCHED_CPUFREQ_IOWAIT flag is set frequently, we don't start
boosting steps unless we see two consecutive flags in two ticks. This
avoids boosting due to IO because of regular system activities.

To avoid synchronization issues, the actual processing of the flag is
done on the local CPU callback.

Reported-by: Mel Gorman <mgorman@techsingularity.net>
Tested-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add HWP boost utility and sched util hooks

Added two utility functions to HWP boost up gradually and boost down to
the default cached HWP request values.

Boost up:
Boost up updates HWP request minimum value in steps. This minimum value
can reach upto at HWP request maximum values depends on how frequently,
this boost up function is called. At max, boost up will take three steps
to reach the maximum, depending on the current HWP request levels and HWP
capabilities. For example, if the current settings are:
If P0 (Turbo max) = P1 (Guaranteed max) = min
No boost at all.
If P0 (Turbo max) > P1 (Guaranteed max) = min
Should result in one level boost only for P0.
If P0 (Turbo max) = P1 (Guaranteed max) > min
Should result in two level boost:
(min + p1)/2 and P1.
If P0 (Turbo max) > P1 (Guaranteed max) > min
Should result in three level boost:
(min + p1)/2, P1 and P0.
We don't set any level between P0 and P1 as there is no guarantee that
they will be honored.

Boost down:
After the system is idle for hold time of 3ms, the HWP request is reset
to the default value from HWP init or user modified one via sysfs.

Caching of HWP Request and Capabilities
Store the HWP request value last set using MSR_HWP_REQUEST and read
MSR_HWP_CAPABILITIES. This avoid reading of MSRs in the boost utility
functions.

These boost utility functions calculated limits are based on the latest
HWP request value, which can be modified by setpolicy() callback. So if
user space modifies the minimum perf value, that will be accounted for
every time the boost up is called. There will be case when there can be
contention with the user modified minimum perf, in that case user value
will gain precedence. For example just before HWP_REQUEST MSR is updated
from setpolicy() callback, the boost up function is called via scheduler
tick callback. Here the cached MSR value is already the latest and limits
are updated based on the latest user limits, but on return the MSR write
callback called from setpolicy() callback will update the HWP_REQUEST
value. This will be used till next time the boost up function is called.

In addition add a variable to control HWP dynamic boosting. When HWP
dynamic boost is active then set the HWP specific update util hook. The
contents in the utility hooks will be filled in the subsequent patches.

Reported-by: Mel Gorman <mgorman@techsingularity.net>
Tested-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: allow trace in passive mode

Allow use of the trace_pstate_sample trace function
when the intel_pstate driver is in passive mode.
Since the core_busy and scaled_busy fields are not
used, and it might be desirable to know which path
through the driver was used, either intel_cpufreq_target
or intel_cpufreq_fast_switch, re-task the core_busy
field as a flag indicator.

The user can then use the intel_pstate_tracer.py utility
to summarize and plot the trace.

Note: The core_busy feild still goes by that name
in include/trace/events/power.h and within the
intel_pstate_tracer.py script and csv file headers,
but it is graphed as "performance", and called
core_avg_perf now in the intel_pstate driver.

Sometimes, in passive mode, the driver is not called for
many tens or even hundreds of seconds. The user
needs to understand, and not be confused by, this limitation.

Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Do not include debugfs.h

The intel_pstate driver doesn't use debugfs any more, so drop
linux/debugfs.h from the list of included headers in it.

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

cpufreq: intel_pstate: Enable HWP during system resume on CPU0

When maxcpus=1 is in the kernel command line, the BP is responsible
for re-enabling the HWP - because currently only the APs invoke
intel_pstate_hwp_enable() during their online process - which might
put the system into unstable state after resume.

Fix this by enabling the HWP explicitly on BP during resume.

Reported-by: Doug Smythies <dsmythies@telus.net>
Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Yu Chen <yu.c.chen@intel.com>
[ rjw: Subject/changelog, minor modifications ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add Skylake servers support

Currently intel_pstate can function only in HWP mode on Skylake servers.
When HWP feature is not enabled on the processor then acpi-cpufreq is
driver is used.

Based on the power and performance tests using intel_pstate scaling
algorithm the results are comparable. But intel_pstate brings in
additional features:
- Display of turbo frequency range, which many users like to see
- Place limits in the turbo frequency range when platform allows

Since these tests are done only using non PID algorithm introduced in
kernel version 4.14, this patch is not a backport candidate. So each user
has to carefully weigh the benefits before he backports.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Replace bxt_funcs with core_funcs

Since core_funcs and bxt_funcs have same set of callbacks, replace
bxt_funcs with core_funcs.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

intel_pstate: convert to use acpi_match_platform_list()

Convert to use acpi_match_platform_list() for the platform check.
There is no change in functionality.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: remove setting of policy->cpu in policy->cpus during init

policy->cpu is copied into policy->cpus in cpufreq_online() before
calling into cpufreq_driver->init(). So there's no need to set the
same in the individual driver init() functions again.

This patch removes the redundant setting of policy->cpu in policy->cpus
in intel_pstate and cppc drivers.

Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
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>

cpufreq: intel_pstate: report correct CPU frequencies during trace

The intel_pstate CPU frequency scaling driver has always
calculated CPU frequency incorrectly. Recent changes have
eliminted most of the issues, however the frequency reported
in the trace buffer, if used, is incorrect.

It remains desireable that cpu->pstate.scaling still be a nice
round number for things such as when setting max and min frequencies.
So the proposal is to just fix the reported frequency in the trace data.

Fixes what remains of [1].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=96521 # [1]
Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Shorten a couple of long names

The names of the INTEL_PSTATE_DEFAULT_SAMPLING_INTERVAL symbol and
the get_target_pstate_use_cpu_load() function don't need to be so
long any more, so make them shorter.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Simplify intel_pstate_adjust_pstate()

Since there is only one P-state selection routine in intel_pstate
now, make intel_pstate_adjust_pstate() call it directly and drop
the target_pstate argument from that function.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Improve IO performance with per-core P-states

In the current implementation, the response latency between seeing
SCHED_CPUFREQ_IOWAIT set and the actual P-state adjustment can be up
to 10ms. It can be reduced by bumping up the P-state to the max at
the time SCHED_CPUFREQ_IOWAIT is passed to intel_pstate_update_util().
With this change, the IO performance improves significantly.

For a simple "grep -r . linux" (Here linux is the kernel source
folder) with caches dropped every time on a Broadwell Xeon workstation
with per-core P-states, the user and system time is shorter by as much
as 30% - 40%.

The same performance difference was not observed on clients that don't
support per-core P-state.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

sched: cpufreq: Allow remote cpufreq callbacks

With Android UI and benchmarks the latency of cpufreq response to
certain scheduling events can become very critical. Currently, callbacks
into cpufreq governors are only made from the scheduler if the target
CPU of the event is the same as the current CPU. This means there are
certain situations where a target CPU may not run the cpufreq governor
for some time.

One testcase to show this behavior is where a task starts running on
CPU0, then a new task is also spawned on CPU0 by a task on CPU1. If the
system is configured such that the new tasks should receive maximum
demand initially, this should result in CPU0 increasing frequency
immediately. But because of the above mentioned limitation though, this
does not occur.

This patch updates the scheduler core to call the cpufreq callbacks for
remote CPUs as well.

The schedutil, ondemand and conservative governors are updated to
process cpufreq utilization update hooks called for remote CPUs where
the remote CPU is managed by the cpufreq policy of the local CPU.

The intel_pstate driver is updated to always reject remote callbacks.

This is tested with couple of usecases (Android: hackbench, recentfling,
galleryfling, vellamo, Ubuntu: hackbench) on ARM hikey board (64 bit
octa-core, single policy). Only galleryfling showed minor improvements,
while others didn't had much deviation.

The reason being that this patch only targets a corner case, where
following are required to be true to improve performance and that
doesn't happen too often with these tests:

- Task is migrated to another CPU.
- The task has high demand, and should take the target CPU to higher
OPPs.
- And the target CPU doesn't call into the cpufreq governor until the
next tick.

Based on initial work from Steve Muckle.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop INTEL_PSTATE_HWP_SAMPLING_INTERVAL

After commit 62611cb912f7 (intel_pstate: delete scheduler hook in HWP
mode) the INTEL_PSTATE_HWP_SAMPLING_INTERVAL is not used anywhere in
the code, so drop it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop ->get from intel_pstate structure

The ->get callback in the intel_pstate structure was mostly there
for the scaling_cur_freq sysfs attribute to work, but after commit
f8475cef9008 (x86: use common aperfmperf_khz_on_cpu() to calculate
KHz using APERF/MPERF) that attribute uses arch_freq_get_on_cpu()
provided by the x86 arch code on all processors supported by
intel_pstate, so it doesn't need the ->get callback from the
driver any more.

Moreover, the very presence of the ->get callback in the intel_pstate
structure causes the cpuinfo_cur_freq attribute to be present when
intel_pstate operates in the active mode, which is bogus, because
the role of that attribute is to return the current CPU frequency
as seen by the hardware. For intel_pstate, though, this is just an
average frequency and not really current, but computed for the
previous sampling interval (the actual current frequency may be
way different at the point this value is obtained by reading from
cpuinfo_cur_freq), and after commit 82b4e03e01bc (intel_pstate: skip
scheduler hook when in "performance" mode) the value in
cpuinfo_cur_freq may be stale or just 0, depending on the driver's
operation mode. In fact, however, on the hardware supported by
intel_pstate there is no way to read the current CPU frequency
from it, so the cpuinfo_cur_freq attribute should not be present
at all when this driver is in use.

For this reason, drop intel_pstate_get() and clear the ->get
callback pointer pointing to it, so that the cpuinfo_cur_freq is
not present for intel_pstate in the active mode any more.

Fixes: 82b4e03e01bc (intel_pstate: skip scheduler hook when in "performance" mode)
Reported-by: Huaisheng Ye <yehs1@lenovo.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: intel_pstate: Drop ->update_util from pstate_funcs

All systems use the same P-state selection "powersave" algorithm
in the active mode if HWP is not used, so there's no need to provide
a pointer for it in struct pstate_funcs any more.

Drop ->update_util from struct pstate_funcs and make
intel_pstate_set_update_util_hook() use intel_pstate_update_util()
directly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Do not use PID-based P-state selection

All systems with a defined ACPI preferred profile that are not
"servers" have been using the load-based P-state selection algorithm
in intel_pstate since 4.12-rc1 (mobile systems and laptops have been
using it since 4.10-rc1) and no problems with it have been reported
to date. In particular, no regressions with respect to the PID-based
P-state selection have been reported. Also testing indicates that
the P-state selection algorithm based on CPU load is generally on par
with the PID-based algorithm performance-wise, and for some workloads
it turns out to be better than the other one, while being more
straightforward and easier to understand at the same time.

Moreover, the PID-based P-state selection algorithm in intel_pstate
is known to be unstable in some situation and generally problematic,
the issues with it are hard to address and it has become a
significant maintenance burden.

For these reasons, make intel_pstate use the "powersave" P-state
selection algorithm based on CPU load in the active mode on all
systems and drop the PID-based P-state selection code along with
all things related to it from the driver. Also update the
documentation accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: Don't set transition_latency for setpolicy drivers

The transition_latency field isn't used for drivers with ->setpolicy()
callback present and there is no point setting it from the drivers.

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

cpufreq: intel_pstate: Correct the busy calculation for KNL

The busy percent calculated for the Knights Landing (KNL) platform
is 1024 times smaller than the correct busy value. This causes
performance to get stuck at the lowest ratio.

The scaling algorithm used for KNL is performance-based, but it still
looks at the CPU load to set the scaled busy factor to 0 when the
load is less than 1 percent. In this case, since the computed load
is 1024x smaller than it should be, the scaled busy factor will
always be 0, irrespective of CPU business.

This needs a fix similar to the turbostat one in commit b2b34dfe4d9a
(tools/power turbostat: KNL workaround for %Busy and Avg_MHz).

For this reason, add one more callback to processor-specific
callbacks to specify an MPERF multiplier represented by a number of
bit positions to shift the value of that register to the left to
copmensate for its rate difference with respect to the TSC. This
shift value is used during CPU busy calculations.

Fixes: ffb810563c (intel_pstate: Avoid getting stuck in high P-states when idle)
Reported-and-tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 4.6+ <stable@vger.kernel.org> # 4.6+
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix ratio setting for min_perf_pct

When the minimum performance limit percentage is set to the power-up
default, it is possible that minimum performance ratio is off by one.

In the set_policy() callback the minimum ratio is calculated by
applying global.min_perf_pct to turbo_ratio and rounding up, but the
power-up default global.min_perf_pct is already rounded up to the
next percent in min_perf_pct_min(). That results in two round up
operations, so for the default min_perf_pct one of them is not
required.

It is better to remove rounding up in min_perf_pct_min() as this
matches the displayed min_perf_pct prior to commit c5a2ee7dde89
(cpufreq: intel_pstate: Active mode P-state limits rework) in 4.12.

For example on a platform with max turbo ratio of 37 and minimum
ratio of 10, the min_perf_pct resulted in 28 with the above commit.
Before this commit it was 27 and it will be the same after this
change.

Fixes: 1a4fe38add8b (cpufreq: intel_pstate: Remove max/min fractions to limit performance)
Reported-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: constify attribute_group structures

attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.

File size before:
text data bss dec hex filename
15197 2552 40 17789 457d drivers/cpufreq/intel_pstate.o

File size After adding 'const':
text data bss dec hex filename
15261 2488 40 17789 457d drivers/cpufreq/intel_pstate.o

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Clean up after performance governor changes

After commit 82b4e03e01bc (intel_pstate: skip scheduler hook when in
"performance" mode) get_target_pstate_use_performance() and
get_target_pstate_use_cpu_load() are never called if scaling_governor
is "performance", so drop the CPUFREQ_POLICY_PERFORMANCE checks from
them as they will never trigger anyway.

Moreover, the documentation needs to be updated to reflect the change
made by the above commit, so do that too.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

intel_pstate: skip scheduler hook when in "performance" mode

When the governor is set to "performance", intel_pstate does not
need the scheduler hook for doing any calculations. Under these
conditions, its only purpose is to continue to maintain
cpufreq/scaling_cur_freq.

The cpufreq/scaling_cur_freq sysfs attribute is now provided by
shared x86 cpufreq code on modern x86 systems, including
all systems supported by the intel_pstate driver.

So in "performance" governor mode, the scheduler hook can be skipped.
This applies to both in Software and Hardware P-state control modes.

Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

intel_pstate: delete scheduler hook in HWP mode

The cpufreq/scaling_cur_freq sysfs attribute is now provided by
shared x86 cpufreq code on modern x86 systems, including
all systems supported by the intel_pstate driver.

In HWP mode, maintaining that value was the sole purpose of
the scheduler hook, intel_pstate_update_util_hwp(),
so it can now be removed.

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Remove max/min fractions to limit performance

In the current model the max/min perf limits are a fraction of current
user space limits to the allowed max_freq or 100% for global limits.
This results in wrong ratio limits calculation because of rounding
issues for some user space limits.

Initially we tried to solve this issue by issue by having more shift
bits to increase precision. Still there are isolated cases where we still
have error.

This can be avoided by using ratios all together. Since the way we get
cpuinfo.max_freq is by multiplying scaling factor to max ratio, we can
easily keep the max/min ratios in terms of ratios and not fractions.

For example:
if the max ratio = 36
cpuinfo.max_freq = 36 * 100000 = 3600000

Suppose user space sets a limit of 1200000, then we can calculate
max ratio limit as
= 36 * 1200000 / 3600000
= 12
This will be correct for any user limits.

The other advantage is that, we don't need to do any calculation in the
fast path as ratio limit is already calculated via set_policy() callback.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Avoid division by 0 in min_perf_pct_min()

Commit c5a2ee7dde89 (cpufreq: intel_pstate: Active mode P-state
limits rework) incorrectly assumed that pstate.turbo_pstate would
always be nonzero for CPU0 in min_perf_pct_min() if
cpufreq_register_driver() had succeeded which may not be the case
in virtualized environments.

If that assumption doesn't hold, it leads to an early crash on boot
in intel_pstate_register_driver(), so add a sanity check to
min_perf_pct_min() to prevent the crash from happening.

Fixes: c5a2ee7dde89 (cpufreq: intel_pstate: Active mode P-state limits rework)
Reported-and-tested-by: Jongman Heo <jongman.heo@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

intel_pstate: use updated msr-index.h HWP.EPP values

intel_pstate exports sysfs attributes for setting and observing HWP.EPP.
These attributes use strings to describe 4 operating states, and
inside the driver, these strings are mapped to numerical register
values.

The authorative mapping between the strings and numerical HWP.EPP values
are now globally defined in msr-index.h, replacing the out-dated
mapping that were open-coded into intel_pstate.c

new old string
--- --- ------
0 0 performance
128 64 balance_performance
192 128 balance_power
255 192 power

Note that the HW and BIOS default value on most system is 128,
which intel_pstate will now call "balance_performance"
while it used to call it "balance_power".

Signed-off-by: Len Brown <len.brown@intel.com>

cpufreq: schedutil: Use policy-dependent transition delays

Make the schedutil governor take the initial (default) value of the
rate_limit_us sysfs attribute from the (new) transition_delay_us
policy parameter (to be set by the scaling driver).

That will allow scaling drivers to make schedutil use smaller default
values of rate_limit_us and reduce the default average time interval
between consecutive frequency changes.

Make intel_pstate set transition_delay_us to 500.

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

cpufreq: intel_pstate: Add support for Gemini Lake

Use same parameters as INTEL_FAM6_ATOM_GOLDMONT to enable
Gemini Lake.

Signed-off-by: Box, David E <david.e.box@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Eliminate intel_pstate_get_min_max()

Some computations in intel_pstate_get_min_max() are not necessary
and one of its two callers doesn't even use the full result.

First off, the fixed-point value of cpu->max_perf represents a
non-negative number between 0 and 1 inclusive and cpu->min_perf
cannot be greater than cpu->max_perf. It is not necessary to check
those conditions every time the numbers in question are used.

Moreover, since intel_pstate_max_within_limits() only needs the
upper boundary, it doesn't make sense to compute the lower one in
there and returning min and max from intel_pstate_get_min_max()
via pointers doesn't look particularly nice.

For the above reasons, drop intel_pstate_get_min_max(), add a helper
to get the base P-state for min/max computations and carry out them
directly in the previous callers of intel_pstate_get_min_max().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Do not walk policy->cpus

intel_pstate_hwp_set() is the only function walking policy->cpus
in intel_pstate. The rest of the code simply assumes one CPU per
policy, including the initialization code.

Therefore it doesn't make sense for intel_pstate_hwp_set() to
walk policy->cpus as it is guaranteed to have only one bit set
for policy->cpu.

For this reason, rearrange intel_pstate_hwp_set() to take the CPU
number as the argument and drop the loop over policy->cpus from it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Introduce pid_in_use()

Add a new function pid_in_use() to return the information on whether
or not the PID-based P-state selection algorithm is in use.

That allows a couple of complicated conditions in the code to be
reduced to simple checks against the new function's return value.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop struct cpu_defaults

The cpu_defaults structure is redundant, because it only contains
one member of type struct pstate_funcs which can be used directly
instead of struct cpu_defaults.

For this reason, drop struct cpu_defaults, use struct pstate_funcs
directly instead of it where applicable and rename all of the
variables of that type accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Move cpu_defaults definitions

Move the definitions of the cpu_defaults structures after the
definitions of utilization update callback routines to avoid
extra declarations of the latter.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add update_util callback to pstate_funcs

Avoid using extra function pointers during P-state selection by
dropping the get_target_pstate member from struct pstate_funcs,
adding a new update_util callback to it (to be registered with
the CPU scheduler as the utilization update callback in the active
mode) and reworking the utilization update callback routines to
invoke specific P-state selection functions directly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use different utilization update callbacks

Notice that some overhead in the utilization update callbacks
registered by intel_pstate in the active mode can be avoided if
those callbacks are tailored to specific configurations of the
driver. For example, the utilization update callback for the HWP
enabled case only needs to update the average CPU performance
periodically whereas the utilization update callback for the
PID-based algorithm does not need to take IO-wait boosting into
account and so on.

With that in mind, define three utilization update callbacks for
three different use cases: HWP enabled, the CPU load "powersave"
P-state selection algorithm and the PID-based "powersave" P-state
selection algorithm and modify the driver initialization to
choose the callback matching its current configuration.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Modify check in intel_pstate_update_status()

One of the checks in intel_pstate_update_status() implicitly relies
on the information that there are only two struct cpufreq_driver
objects available, but it is better to do it directly against the
value it really is about (to make the code easier to follow if
nothing else).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop driver_registered variable

The driver_registered variable in intel_pstate is used for checking
whether or not the driver has been registered, but intel_pstate_driver
can be used for that too (with the rule that the driver is not
registered as long as it is NULL).

That is a bit more straightforward and the code may be simplified
a bit this way, so modify the driver accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Skip unnecessary PID resets on init

PID controller parameters only need to be initialized if the
get_target_pstate_use_performance() P-state selection routine
is going to be used. It is not necessary to initialize them
otherwise, so don't do that.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Set HWP sampling interval once

In the HWP enabled case pid_params.sample_rate_ns only needs to be
updated once, because it is global, so do that when setting hwp_active
instead of doing it during the initialization of every CPU.

Moreover, pid_params.sample_rate_ms is never used if HWP is enabled,
so do not update it at all then.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Clean up intel_pstate_busy_pid_reset()

intel_pstate_busy_pid_reset() is the only caller of pid_reset(),
pid_p_gain_set(), pid_i_gain_set(), and pid_d_gain_set(). Moreover,
it passes constants as two parameters of pid_reset() and all of
the other routines above essentially contain the same code, so
fold all of them into the caller and drop unnecessary computations.

Introduce percent_fp() for converting integer values in percent
to fixed-point fractions and use it in the above code cleanup.

Finally, rename intel_pstate_busy_pid_reset() to
intel_pstate_pid_reset() as it also is used for the
initialization of PID parameters for every CPU and the
meaning of the "busy" part of the name is not particularly
clear.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fold intel_pstate_reset_all_pid() into the caller

There is only one caller of intel_pstate_reset_all_pid(), which is
pid_param_set() used in the debugfs interface only, and having that
code split does not make it particularly convenient to follow.

For this reason, move the body of intel_pstate_reset_all_pid() into
its caller and drop that function.

Also change the loop from for_each_online_cpu() (which is obviously
racy with respect to CPU offline/online) to for_each_possible_cpu(),
so that all PID parameters are reset for all CPUs regardless of their
online/offline status (to prevent, for example, a previously offline
CPU from going online with a stale set of PID parameters).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Initialize pid_params statically

Notice that both the existing struct cpu_defaults instances in which
PID parameters are actually initialized use the same values of those
parameters, so it is not really necessary to copy them over to
pid_params dynamically.

Instead, initialize pid_params statically with those values and
drop the unused pid_policy member from struct cpu_defaults along
with copy_pid_params() used for initializing it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop pointless initialization of PID parameters

The P-state selection algorithm used by intel_pstate for Atom
processors is not based on the PID controller and the initialization
of PID parametrs for those processors is pointless and confusing, so
drop it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Eliminate struct perf_limits

After recent changes the purpose of struct perf_limits is not
particularly clear any more and the code may be made somewhat
easier to follow by eliminating it, so go for that.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Avoid transient updates of cpuinfo.max_freq

Both intel_pstate_verify_policy() and intel_cpufreq_verify_policy()
set policy->cpuinfo.max_freq depending on the turbo status, but the
updates made by them are discarded by the core, because the policy
object passed to them by the core is temporary and cpuinfo.max_freq
from that object is not copied to the final policy object in
cpufreq_set_policy().

However, cpufreq_set_policy() passes the temporary policy object
to the ->setpolicy callback of the driver, so intel_pstate_set_policy()
actually sees the policy->cpuinfo.max_freq value updated by
intel_pstate_verify_policy() and not the final one. It also
updates policy->max sometimes which basically has no effect after
it returns, because the core discards that update.

To avoid confusion, eliminate policy->cpuinfo.max_freq updates from
intel_pstate_verify_policy() and intel_cpufreq_verify_policy()
entirely and check the maximum frequency explicitly in
intel_pstate_update_perf_limits() instead of relying on the
transiently updated policy->cpuinfo.max_freq value.

Moreover, move the max->policy adjustment carried out in
intel_pstate_set_policy() to a separate function and call that
function from the ->verify driver callbacks to ensure that it will
actually be effective.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Active mode P-state limits rework

The coordination of P-state limits used by intel_pstate in the active
mode (ie. by default) is problematic, because it synchronizes all of
the limits (ie. the global ones and the per-policy ones) so as to use
one common pair of P-state limits (min and max) across all CPUs in
the system. The drawbacks of that are as follows:

- If P-states are coordinated in hardware, it is not necessary
to coordinate them in software on top of that, so in that case
all of the above activity is in vain.

- If P-states are not coordinated in hardware, then the processor
is actually capable of setting different P-states for different
CPUs and coordinating them at the software level simply doesn't
allow that capability to be utilized.

- The coordination works in such a way that setting a per-policy
limit (eg. scaling_max_freq) for one CPU causes the common
effective limit to change (and it will affect all of the other
CPUs too), but subsequent reads from the corresponding sysfs
attributes for the other CPUs will return stale values (which
is confusing).

- Reads from the global P-state limit attributes, min_perf_pct and
max_perf_pct, return the effective common values and not the last
values set through these attributes. However, the last values
set through these attributes become hard limits that cannot be
exceeded by writes to scaling_min_freq and scaling_max_freq,
respectively, and they are not exposed, so essentially users
have to remember what they are.

All of that is painful enough to warrant a change of the management
of P-state limits in the active mode.

To that end, redesign the active mode P-state limits management in
intel_pstate in accordance with the following rules:

(1) All CPUs are affected by the global limits (that is, none of
them can be requested to run faster than the global max and
none of them can be requested to run slower than the global
min).

(2) Each individual CPU is affected by its own per-policy limits
(that is, it cannot be requested to run faster than its own
per-policy max and it cannot be requested to run slower than
its own per-policy min).

(3) The global and per-policy limits can be set independently.

Also, the global maximum and minimum P-state limits will be always
expressed as percentages of the maximum supported turbo P-state.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use load-based P-state selection more widely

Extend the set of systems for which intel_pstate will use the
"powersave" P-state selection algorithm based on CPU load in the
active mode by systems with ACPI preferred profile set to "tablet",
"appliance PC", "desktop", or "workstation" (ie. everything with a
specified preferred profile that is not a "server").

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Support HWP processors in all operation modes

Currently, some processors supporting HWP are only supported by
intel_pstate if HWP is actually going to be used and not supported
otherwise which is confusing.

Specifically, they are not supported if "intel_pstate=no_hwp" is
passed to the kernel in the command line or if the driver is started
in the passive mode ("intel_pstate=passive").

There is no real reason for that, because everything about those
processor is known anyway and the driver can work with them in all
modes, so make that happen, but use the load-based P-state selection
algorithm for the active mode "powersave" policy with them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix policy data management in passive mode

The policy->cpuinfo.max_freq and policy->max updates in
intel_cpufreq_turbo_update() are excessive as they are done for no
good reason and may lead to problems in principle, so they should be
dropped. However, after dropping them intel_cpufreq_turbo_update()
becomes almost entirely pointless, because the check made by it is
made again down the road in intel_pstate_prepare_request(). The
only thing in it that still needs to be done is the call to
update_turbo_state(), so drop intel_cpufreq_turbo_update() altogether
and make its callers invoke update_turbo_state() directly instead of
it.

In addition to that, fix intel_cpufreq_verify_policy() so that it
checks global.no_turbo in addition to global.turbo_disabled when
updating policy->cpuinfo.max_freq to make it consistent with
intel_pstate_verify_policy().

Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: One set of global limits in active mode

In the active mode intel_pstate currently uses two sets of global
limits, each associated with one of the possible scaling_governor
settings in that mode: "powersave" or "performance".

The driver switches over from one of those sets to the other
depending on the scaling_governor setting for the last CPU whose
per-policy cpufreq interface in sysfs was last used to change
parameters exposed in there. That obviously leads to no end of
issues when the scaling_governor settings differ between CPUs.

The most recent issue was introduced by commit a240c4aa5d0f (cpufreq:
intel_pstate: Do not reinit performance limits in ->setpolicy)
that eliminated the reinitialization of "performance" limits in
intel_pstate_set_policy() preventing the max limit from being set
to anything below 100, among other things.

Namely, an undesirable side effect of commit a240c4aa5d0f is that
now, after setting scaling_governor to "performance" in the active
mode, the per-policy limits for the CPU in question go to the highest
level and stay there even when it is switched back to "powersave"
later.

As it turns out, some distributions set scaling_governor to
"performance" temporarily for all CPUs to speed-up system
initialization, so that change causes them to misbehave later.

To fix that, get rid of the performance/powersave global limits
split and use just one set of global limits for everything.

From the user's persepctive, after this modification, when
scaling_governor is switched from "performance" to "powersave"
or the other way around on one CPU, the limits settings (ie. the
global max/min_perf_pct and per-policy scaling_max/min_freq for
any CPUs) will not change. Still, switching from "performance"
to "powersave" or the other way around changes the way in which
P-states are selected and in particular "performance" causes the
driver to always request the highest P-state it is allowed to ask
for for the given CPU.

Fixes: a240c4aa5d0f (cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Avoid percentages in limits-related computations

Currently, intel_pstate_update_perf_limits() first converts the
policy minimum and maximum limits into percentages of the maximum
turbo frequency (rounding up to an integer) and then converts these
percentages to fractions (by using fixed-point arithmetic to divide
them by 100).

That introduces a rounding error unnecessarily, because the fractions
can be obtained by carrying out fixed-point divisions directly on the
input numbers.

Rework the computations in intel_pstate_hwp_set() to use fractions
instead of percentages (and drop redundant local variables from
there) and modify intel_pstate_update_perf_limits() to compute the
fractions directly and percentages out of them.

While at it, introduce percent_ext_fp() for converting percentages
to fractions (with extended number of fraction bits) and use it in
the computations.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Correct frequency setting in the HWP mode

In the functions intel_pstate_hwp_set(), min/max range from HWP capability
MSR along with max_perf_pct and min_perf_pct, is used to set the HWP
request MSR. In some cases this doesn't result in the correct HWP max/min
in HWP request.

For example: In the following case:

HWP capabilities from MSR 0x771
0x70a1220

Here cpufreq min/max frequencies from above MSR dump are 700MHz and 3.2GHz
respectively.

This will result in
hwp_min = 0x07
hwp_max = 0x20

To limit max frequency to 2GHz:

perf_limits->max_perf_pct = 63 (2GHz as a percent of 3.2GHz rounded up)

With the current calculation:
adj_range = max_perf_pct * range / 100;
adj_range = 63 * (32 - 7) / 100
adj_range = 15

max = hw_min + adj_range;
max = 7 + 15 = 22

This will result in HWP request of 0x160f, which will result in a
frequency cap of 2.2GHz not 2GHz.

The problem with the above calculation is that hwp_min of 7 is treated
as 0% in the range. But max_perf_pct is calculated with respect to minimum
as 0 and max as 3.2GHz or hwp_max, so adding hwp_min to it will result in
more than the desired.

Since the min_perf_pct and max_perf_pct is already a percent of max
frequency or hwp_max, this min/max HWP request value can be calculated
directly applying these percentage to hwp_max.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Update pid_params.sample_rate_ns in pid_param_set()

Fix the debugfs interface for PID tuning to actually update
pid_params.sample_rate_ns on PID parameters updates, as changing
pid_params.sample_rate_ms via debugfs has no effect now.

Fixes: a4675fbc4a7a (cpufreq: intel_pstate: Replace timers with utilization update callbacks)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: intel_pstate: Drop redundant wrapper function

intel_pstate_hwp_set_policy() is a wrapper around
intel_pstate_hwp_set(), but the only value it adds is to check
hwp_active before calling the latter and one of its two callers
has already checked hwp_active before that happens, so in that
code path the additional check is redundant and using the wrapper
is rather pointless.

For this reason, drop intel_pstate_hwp_set_policy() and make its
callers invoke intel_pstate_hwp_set() directly (after checking
hwp_active).

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

cpufreq: intel_pstate: Do not reinit performance limits in ->setpolicy

If the current P-state selection algorithm is set to "performance"
in intel_pstate_set_policy(), the limits may be initialized from
scratch, but only if no_turbo is not set and the maximum frequency
allowed for the given CPU (i.e. the policy object representing it)
is at least equal to the max frequency supported by the CPU. In all
of the other cases, the limits will not be updated.

For example, the following can happen:

# cat intel_pstate/status
active
# echo performance > cpufreq/policy0/scaling_governor
# cat intel_pstate/min_perf_pct
100
# echo 94 > intel_pstate/min_perf_pct
# cat intel_pstate/min_perf_pct
100
# cat cpufreq/policy0/scaling_max_freq
3100000
echo 3000000 > cpufreq/policy0/scaling_max_freq
# cat intel_pstate/min_perf_pct
94
# echo 95 > intel_pstate/min_perf_pct
# cat intel_pstate/min_perf_pct
95

That is confusing for two reasons. First, the initial attempt to
change min_perf_pct to 94 seems to have no effect, even though
setting the global limits should always work. Second, after
changing scaling_max_freq for policy0 the global min_perf_pct
attribute shows 94, even though it should have not been affected
by that operation in principle.

Moreover, the final attempt to change min_perf_pct to 95 worked
as expected, because scaling_max_freq for the only policy with
scaling_governor equal to "performance" was different from the
maximum at that time.

To make all that confusion go away, modify intel_pstate_set_policy()
so that it doesn't reinitialize the limits at all.

At the same time, change intel_pstate_set_performance_limits() to
set min_sysfs_pct to 100 in the "performance" limits set so that
switching the P-state selection algorithm to "performance" causes
intel_pstate/min_perf_pct in sysfs to go to 100 (or whatever value
min_sysfs_pct in the "performance" limits is set to later).

That requires per-CPU limits to be initialized explicitly rather
than by copying the global limits to avoid setting min_sysfs_pct
in the per-CPU limits to 100.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix intel_pstate_verify_policy()

The code added to intel_pstate_verify_policy() by commit 1443ebbacfd7
(cpufreq: intel_pstate: Fix sysfs limits enforcement for performance
policy) should use perf_limits instead of limits, because otherwise
setting global limits via sysfs may affect policies inconsistently.

For example, in the sequence of shell commands below, the
scaling_min_freq attribute for policy1 and policy2 should be
affected in the same way, because scaling_governor is set in
the same way for both of them:

# cat cpufreq/policy1/scaling_governor
powersave
# cat cpufreq/policy2/scaling_governor
powersave
# echo performance > cpufreq/policy0/scaling_governor
# echo 94 > intel_pstate/min_perf_pct
# cat cpufreq/policy0/scaling_min_freq
2914000
# cat cpufreq/policy1/scaling_min_freq
2914000
# cat cpufreq/policy2/scaling_min_freq
800000

The are affected differently, because intel_pstate_verify_policy()
is invoked with limits set to &performance_limits (left behind by
policy0) for policy1 and with limits set to &powersave_limits (left
behind by policy1) for policy2. Since perf_limits is set to the
set of limits matching the policy being updated, using it instead
of limits fixes the inconsistency.

Fixes: 1443ebbacfd7 (cpufreq: intel_pstate: Fix sysfs limits enforcement for performance policy)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix global settings in active mode

Commit 111b8b3fe4fa (cpufreq: intel_pstate: Always keep all
limits settings in sync) changed intel_pstate to invoke
cpufreq_update_policy() for every registered CPU on global sysfs
attributes updates, but that led to undesirable effects in the
active mode if the "performance" P-state selection algorithm is
configufred for one CPU and the "powersave" one is chosen for
all of the other CPUs.

Namely, in that case, the following is possible:

# cd /sys/devices/system/cpu/
# cat intel_pstate/max_perf_pct
100
# cat intel_pstate/min_perf_pct
26
# echo performance > cpufreq/policy0/scaling_governor
# cat intel_pstate/max_perf_pct
100
# cat intel_pstate/min_perf_pct
100
# echo 94 > intel_pstate/min_perf_pct
# cat intel_pstate/min_perf_pct
26

The reason why this happens is because intel_pstate attempts to
maintain two sets of global limits in the active mode, one for
the "performance" P-state selection algorithm and one for the
"powersave" P-state selection algorithm, but the P-state selection
algorithms are set per policy, so the global limits cannot reflect
all of them at the same time if they are different for different
policies.

In the particular situation above, the attempt to change
min_perf_pct to 94 caused cpufreq_update_policy() to be run
for a CPU with the "powersave" P-state selection algorithm
and intel_pstate_set_policy() called by it silently switched the
global limits to the "powersave" set which finally was reflected
by the sysfs interface.

To prevent that from happening, modify intel_pstate_update_policies()
to always switch back to the set of limits that was used right before
it has been invoked.

Fixes: 111b8b3fe4fa (cpufreq: intel_pstate: Always keep all limits settings in sync)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Avoid triggering cpu_frequency tracepoint unnecessarily

In the passive mode the cpu_frequency trace event is already
triggered by the cpufreq core or by scaling governors, so
intel_pstate should not trigger it once again for the same
P-state updates.

In addition to that, the frequency returned by
intel_cpufreq_fast_switch() and passed via freqs.new from
intel_cpufreq_target() to cpufreq_freq_transition_end() should
reflect the P-state actually set, so make that happen.

Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix intel_cpufreq_verify_policy()

The intel_pstate_update_perf_limits() called from
intel_cpufreq_verify_policy() may cause global P-state limits
to change which is generally confusing and unnecessary.

In the passive mode the global limits are only applied to the
frequency selected by the scaling governor (they are not taken
into account by governors when making decisions anyway), so making
them follow the per-policy limits serves no purpose and may go
against user expectations (as it generally causes the global
attributes in sysfs to change even though they have not been
written to in some cases).

Fix that by dropping the intel_pstate_update_perf_limits()
invocation from intel_cpufreq_verify_policy() (which also
reduces the code size by a few lines).

This change does not affect the per-CPU limits case, because those
limits allow any P-state to be set by default in the passive mode
and it removes the only piece of code updating them in that mode,
so the per-policy settings will be the only ones taken into account
in that case as expected.

Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Do not use performance_limits in passive mode

Using performance_limits in the passive mode doesn't make
sense, because in that mode the global limits are applied to the
frequency selected by the scaling governor.

The maximum and minimum P-state limits in performance_limits are both
set to 100 percent which will put all CPUs into the turbo range
regardless of what governor is used and what frequencies are
selected by it (that is particularly undesirable on CPUs with the
generic powersave governor attached).

For this reason, make intel_pstate_register_driver() always point
limits to powersave_limits in the passive mode.

Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

sched/headers: Prepare for new header dependencies before moving code to <linux/sched/cpufreq.h>

We are going to split <linux/sched/cpufreq.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/cpufreq.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

intel_pstate: use MSR_ATOM_RATIOS definitions from msr-index.h

Originally, these MSRs were locally defined in this driver.
Now the definitions are in msr-index.h -- use them.

Signed-off-by: Len Brown <len.brown@intel.com>

cpufreq: intel_pstate: Fix limits issue with operation mode switching

There is a problem with intel_pstate operation mode switching
introduced by commit fb1fe1041c04 (cpufreq: intel_pstate: Operation
mode control from sysfs), because the global sysfs limits are
preserved across operation modes while per-policy limits are
reinitialized from scratch on a mode switch and both sets of limits
may get out of sync this way.

Fix that by always reinitializing the global limits upon the
registration of the driver.

Fixes: fb1fe1041c04 (cpufreq: intel_pstate: Operation mode control from sysfs)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Disable energy efficiency optimization

Some Kabylake desktop processors may not reach max turbo when running in
HWP mode, even if running under sustained 100% utilization.

This occurs when the HWP.EPP (Energy Performance Preference) is set to
"balance_power" (0x80) -- the default on most systems.

It occurs because the platform BIOS may erroneously enable an
energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not
recommended to be enabled on this SKU.

On the failing systems, this BIOS issue was not discovered when the
desktop motherboard was tested with Windows, because the BIOS also
neglects to provide the ACPI/CPPC table, that Windows requires to enable
HWP, and so Windows runs in legacy P-state mode, where this setting has
no effect.

Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and
so it runs in HWP mode, exposing this incorrect BIOS configuration.

There are several ways to address this problem.

First, Linux can also run in legacy P-state mode on this system.
As intel_pstate is how Linux enables HWP, booting with
"intel_pstate=disable"
will run in acpi-cpufreq/ondemand legacy p-state mode.

Or second, the "performance" governor can be used with intel_pstate,
which will modify HWP.EPP to 0.

Or third, starting in 4.10, the
/sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference
attribute in can be updated from "balance_power" to "performance".

Or fourth, apply this patch, which fixes the erroneous setting of
MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default
configuration to function as designed.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Cc: 4.6+ <stable@vger.kernel.org> # 4.6+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Calculate guaranteed performance for HWP

When HWP is active, turbo activation ratio is not used to calculate max
non turbo ratio. But on these systems the max non turbo ratio is decided
by config TDP settings.

This change removes usage of MSR_TURBO_ACTIVATION_RATIO for HWP systems,
instead directly use TDP ratios, when more than one TDPs are available.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Make HWP limits compatible with legacy

Under HWP the performance limits are calculated using max_perf_pct
and min_perf_pct using possible performance, not available performance.
The available performance can be reduced by no_turbo setting. To make
compatible with legacy mode, use max/min performance percentage with
respect to available performance.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Lower frequency than expected under no_turbo

When turbo is not disabled by BIOS, but user disabled from intel P-State
sysfs and changes max/min using cpufreq sysfs, the resultant frequency
is lower than what user requested.

The reason for this, when the perf limits are calculated in set_policy()
callback, they are with reference to max cpu frequency (turbo frequency
), but when enforced in the intel_pstate_get_min_max() they are with
reference to max available performance as documented in the intel_pstate
documentation (in this case max non turbo P-State).

This needs similar change as done in intel_cpufreq_verify_policy() for
passive mode. Set policy->cpuinfo.max_freq based on the turbo status.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Operation mode control from sysfs

Make it possible to change the operation mode of intel_pstate with
the help of a new sysfs attribute called "status".

There are three possible configurations that can be selected using
this attribute:

"off" - The driver is not in use at this time.
"active" - The driver works as a P-state governor (default).
"passive" - The driver works as a regular cpufreq one and collaborates
with the generic cpufreq governors (it sets P-states as
requested by those governors). [This is the same mode
the driver can be started in by passing intel_pstate=passive
in the kernel command line.]

The current setting is returned by reads from this attribute. Writing
one of the above strings to it changes the operation mode as indicated
by that string, if possible.

If HW-managed P-states (HWP) feature is enabled, it is not possible
to change the driver's operation mode and attempts to write to this
attribute will fail.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Expose global sysfs attributes upfront

Expose the intel_pstate's global sysfs attributes before registering
the driver to prepare for the addition of an attribute that also will
have to work if the driver is not registered.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix sysfs limits enforcement for performance policy

A side effect of keeping intel_pstate sysfs limits in sync with cpufreq
is that the now sysfs limits can't enforced under performance policy.

For example, if the max_perf_pct is changed from 100 to 80, this will call
intel_pstate_set_policy(), which will change the max_perf to 100 again for
performance policy. Same issue happens, when no_turbo is set.

This change calculates max and min frequency using sysfs performance
limits in intel_pstate_verify_policy() and adjusts policy limits by
calling cpufreq_verify_within_limits().

Also, it causes the setting of performance limits to be skipped if
no_turbo is set.

Fixes: 111b8b3fe4fa (cpufreq: intel_pstate: Always keep all limits settings in sync)
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Always keep all limits settings in sync

Make intel_pstate update per-logical-CPU limits when the global
settings are changed to ensure that they are always in sync and
users will not see confusing values in per-logical-CPU sysfs
attributes.

This also fixes the problem that setting the "no_turbo" global
attribute to 1 in the "passive" mode (ie. when intel_pstate acts
as a regular cpufreq driver) when scaling_governor is set to
"performance" has no effect.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Use locking in intel_cpufreq_verify_policy()

Race conditions are possible if intel_cpufreq_verify_policy()
is executed in parallel with global limits updates from sysfs,
so the invocation of intel_pstate_update_perf_limits() in it
should be carried out under intel_pstate_limits_lock.

Make that happen.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Use locking in intel_pstate_resume()

Theoretically, intel_pstate_resume() may be executed in parallel
with intel_pstate_set_policy(), if the latter is invoked via
cpufreq_update_policy() as a result of a notification, so use
intel_pstate_limits_lock in there too to avoid race conditions.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Do not expose PID parameters in passive mode

If intel_pstate works in the passive mode in which it acts as
a regular cpufreq driver and collaborates with generic cpufreq
governors, the PID parameters are not used, so do not expose
them via debugfs in that case.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Support for energy performance hints with HWP

It is possible to provide hints to the HWP algorithms in the processor
to be more performance centric to more energy centric. These hints are
provided by using HWP energy performance preference (EPP) or energy
performance bias (EPB) settings.

The scope of these settings is per logical processor, which means that
each of the logical processors in the package can be programmed with a
different value.

This change provides cpufreq sysfs interface to provide hint. For each
policy, two additional attributes will be available to check and provide
hint. These attributes will only be present when the intel_pstate driver
is using HWP mode.

These attributes are:
- energy_performance_available_preferences
- energy_performance_preference

To get list of supported hints:
$ cat energy_performance_available_preferences
default performance balance_performance balance_power power

The current preference can be read or changed via cpufreq sysfs
attribute "energy_performance_preference". Reading from this attribute
will display current effective setting changed via any method. User can
write any of the valid preference string to this attribute. User can
always restore to power-on default by writing "default".

Implementation
Since these hints can be provided by direct MSR write or using some tools
like x86_energy_perf_policy, the driver internally doesn't maintain any
state. The user operation will result in direct read/write of MSR: 0x774
(HWP_REQUEST_MSR). Also driver use read modify write to update other
fields in this MSR.

Summary of changes:
- struct cpudata field epp_saved is renamed to epp_powersave, as this
stores the value to restore once policy is switched from performance
to powersave to restore original powersave EPP value.
- A new struct cpudata field epp_saved is used to store the raw MSR
EPP/EPB value when a CPU goes offline or on suspend and restore on
online/resume. This ensures that EPP value is restored to correct
value irrespective of the means used to set.
- EPP/EPB value ranges are fixed for each preference, which can be
set for the cpufreq sysfs, so user request is mapped to/from this
range.
- New attributes are only added when HWP is present.
- Since EPP value of 0 is valid the fields are initialized to
-EINVAL when not valid. The field epp_default is read only once
after powerup to avoid reading on subsequent CPU online operation
- New suspend callback to store epp on suspend operation
- Don't invalidate old epp_saved field on resume and online as now
we can restore last epp value on suspend and this field can still
have old EPP value sampled during switch to performance from
powersave.
- While here optimized setting of cpu_data->epp_powersave = epp in
intel_pstate_hwp_set() as this was done in both true and false
paths.
- epp/epb set function returns error to caller on failure to pass
on to user space for display.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add locking around HWP requests

To avoid race conditions from multiple threads, increase the scope
of intel_pstate_limits_lock to include HWP requests also.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add Knights Mill CPUID

Add Knights Mill (KNM) to the list of CPUIDs supported by intel_pstate.

Signed-off-by: Piotr Luc <piotr.luc@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: fix intel_pstate_exit_perf_limits() prototype

The addition of the generic governor support marked the
intel_pstate_exit_perf_limits as inline(), which fixed a warning,
but it introduced another warning:

drivers/cpufreq/intel_pstate.c: In function ‘intel_pstate_exit_perf_limits’:
drivers/cpufreq/intel_pstate.c:483:1: error: no return statement in function returning non-void [-Werror=return-type]

This changes it back to a 'void' return type, and changes the
corresponding intel_pstate_init_acpi_perf_limits() function to
be inline as well for consistency.

Fixes: 001c76f05b01 (cpufreq: intel_pstate: Generic governors support)
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Set EPP/EPB to 0 in performance mode

When user has selected performance policy, then set the EPP (Energy
Performance Preference) or EPB (Energy Performance Bias) to maximum
performance mode.

Also when user switch back to powersave, then restore EPP/EPB to last
EPP/EPB value before entering performance mode. If user has not changed
EPP/EPB manually then it will be power on default value.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq/intel_pstate: Use CPPC to get max performance

Use the acpi cppc_lib interface to get CPPC performance limits and update
the per cpu priority for the ITMT scheduler. If the highest performance of
CPUs differs the ITMT feature is enabled.

Co-developed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: linux-pm@vger.kernel.org
Cc: peterz@infradead.org
Cc: jolsa@redhat.com
Cc: rjw@rjwysocki.net
Cc: linux-acpi@vger.kernel.org
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: bp@suse.de
Link: http://lkml.kernel.org/r/0998b98943bcdec7d1ddd4ff27358da555ea8e92.1479844244.git.tim.c.chen@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

cpufreq: intel_pstate: increase precision of performance limits

Even with round up of limits->min_perf and limits->max_perf, in some
cases resultant performance is 100 MHz less than the desired.

For example when the maximum frequency is 3.50 GHz, setting
scaling_min_frequency to 2.3 GHz always results in 2.2 GHz minimum.

Currently the fixed floating point operation uses 8 bit precision for
calculating limits->min_perf and limits->max_perf. For some operations
in this driver the 14 bit precision is used. Using the 14 bit precision
also for calculating limits->min_perf and limits->max_perf, addresses
this issue.

Introduced fp_ext_toint() equivalent to fp_toint() and int_ext_tofp()
equivalent to int_tofp() with 14 bit precision.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: round up min_perf limits

In some use cases, user wants to enforce a minimum performance limit on
CPUs. But because of simple division the resultant performance is 100 MHz
less than the desired in some cases.

For example when the maximum frequency is 3.50 GHz, setting
scaling_min_frequency to 1.6 GHz always results in 1.5 GHz minimum. With
simple round up, the frequency can be set to 1.6 GHz to minimum in this
case. This round up is already done to max_policy_pct and max_perf, so do
the same for min_policy_pct and min_perf.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Generic governors support

There may be reasons to use generic cpufreq governors (eg. schedutil)
on Intel platforms instead of the intel_pstate driver's internal
governor. However, that currently can only be done by disabling
intel_pstate altogether and using the acpi-cpufreq driver instead
of it, which is subject to limitations.

First of all, acpi-cpufreq only works on systems where the _PSS
object is present in the ACPI tables for all logical CPUs. Second,
on those systems acpi-cpufreq will only use frequencies listed by
_PSS which may be suboptimal. In particular, by convention, the
whole turbo range is represented in _PSS as a single P-state and
the frequency assigned to it is greater by 1 MHz than the greatest
non-turbo frequency listed by _PSS. That may confuse governors to
use turbo frequencies less frequently which may lead to suboptimal
performance.

For this reason, make it possible to use the intel_pstate driver
with generic cpufreq governors as a "normal" cpufreq driver. That
mode is enforced by adding intel_pstate=passive to the kernel
command line and cannot be disabled at run time. In that mode,
intel_pstate provides a cpufreq driver interface including
the ->target() and ->fast_switch() callbacks and is listed in
scaling_driver as "intel_cpufreq".

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Doug Smythies <dsmythies@telus.net>

cpufreq: intel_pstate: Request P-states control from SMM if needed

Currently, intel_pstate is unable to control P-states on my
IvyBridge-based Acer Aspire S5, because they are controlled by SMM
on that machine by default and it is necessary to request OS control
of P-states from it via the SMI Command register exposed in the ACPI
FADT. intel_pstate doesn't do that now, but acpi-cpufreq and other
cpufreq drivers for x86 platforms do.

Address this problem by making intel_pstate use the ACPI-defined
mechanism as well. However, intel_pstate is not modular and it
doesn't need the module refcount tricks played by
acpi_processor_notify_smm(), so export the core of this function
to it as acpi_processor_pstate_control() and make it call that.
[The changes in processor_perflib.c related to this should not
make any functional difference for the acpi_processor_notify_smm()
users].

To be safe, only call acpi_processor_notify_smm() from intel_pstate
if ACPI _PPC support is enabled in it.

Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Use CPU load based algorithm for PM_MOBILE

Use get_target_pstate_use_cpu_load() to calculate target P-State for
devices, with the preferred power management profile in ACPI FADT
set to PM_MOBILE.

This may help in resolving some thermal issues caused by low sustained
cpu bound workloads. The current algorithm tend to over provision in this
case as it doesn't look at the CPU busyness.

Also included the fix from Arnd Bergmann <arnd@arndb.de> to solve compile
issue, when CONFIG_ACPI is not defined.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: protect limits variable

The limits variable gets modified from intel_pstate sysfs and also gets
modified from cpufreq sysfs. So protect with a mutex to keep data
integrity, when they are getting modified from multiple threads.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Reduce impact due to rounding error

When policy->max and policy->min are same, in some cases they don't
result in the same frequency cap. The max_policy_pct is rounded up but
not min_perf_pct. So even when they are same, results in different
percentage or maximum and minimum.
Since minimum is a conservative value for power, a lower value without
rounding is better in most of the cases, unless user wants
policy->max = policy->min.
This change uses use the same policy percentage when policy->max and
policy->min are same.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Per CPU P-State limits

Intel P-State offers two interface to set performance limits:
- Intel P-State sysfs
/sys/devices/system/cpu/intel_pstate/max_perf_pct
/sys/devices/system/cpu/intel_pstate/min_perf_pct
- cpufreq
/sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
/sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq

In the current implementation both of the above methods, change limits
to every CPU in the system. Moreover the limits placed using cpufreq
policy interface also presented in the Intel P-State sysfs via modified
max_perf_pct and min_per_pct during sysfs reads. This allows to check
percent of reduced/increased performance, irrespective of method used to
limit.

There are some new generations of processors, where it is possible to
have limits placed on individual CPU cores. Using cpufreq interface it
is possible to set limits on each CPU. But the current processing will
use last limits placed on all CPUs. So the per core limit feature of
CPUs can't be used.

This change brings in capability to set P-States limits for each CPU,
with some limitations. In this case what should be the read of
max_perf_pct and min_perf_pct? It can be most restrictive limits placed
on any CPU or max possible performance on any given CPU on which no
limits are placed. In either case someone will have issue.

So the consensus is, we can't have both sysfs controls present when user
wants to use limit per core limits.
- By default per-core-control feature is not enabled. So no one will
notice any difference.
- The way to enable is by kernel command line
intel_pstate=per_cpu_perf_limits
- When the per-core-controls are enabled there is no display of for both
read and write on
/sys/devices/system/cpu/intel_pstate/max_perf_pct
/sys/devices/system/cpu/intel_pstate/min_perf_pct
- User can change limits using
/sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
/sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq
/sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
- User can still observe turbo percent and number of P-States from
/sys/devices/system/cpu/intel_pstate/turbo_pct
/sys/devices/system/cpu/intel_pstate/num_pstates
- User can read write system wide turbo status
/sys/devices/system/cpu/no_turbo

While changing this BUG_ON is changed to WARN_ON, as they are not fatal
errors for the system.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Always set max P-state in performance mode

The only times at which intel_pstate checks the policy set for
a given CPU is the initialization of that CPU and updates of its
policy settings from cpufreq when intel_pstate_set_policy() is
invoked.

That is insufficient, however, because intel_pstate uses the same
P-state selection function for all CPUs regardless of the policy
setting for each of them and the P-state limits are shared between
them. Thus if the policy is set to "performance" for a particular
CPU, it may not behave as expected if the cpufreq settings are
changed subsequently for another CPU.

That can be easily demonstrated by writing "performance" to
scaling_governor for all CPUs and then switching it to "powersave"
for one of them in which case all of the CPUs will behave as though
their scaling_governor were all "powersave" (even though the policy
still appears to be "performance" for the remaining CPUs).

Fix this problem by modifying intel_pstate_adjust_busy_pstate() to
always set the P-state to the maximum allowed by the current limits
for all CPUs whose policy is set to "performance".

Note that it still is recommended to always change the policy setting
in the same way for all CPUs even with this fix applied to avoid
confusion.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Set P-state upfront in performance mode

After commit a4675fbc4a7a (cpufreq: intel_pstate: Replace timers with
utilization update callbacks) the cpufreq governor callbacks may not
be invoked on NOHZ_FULL CPUs and, in particular, switching to the
"performance" policy via sysfs may not have any effect on them. That
is a problem, because it usually is desirable to squeeze the last
bit of performance out of those CPUs, so work around it by setting
the maximum P-state (within the limits) in intel_pstate_set_policy()
upfront when the policy is CPUFREQ_POLICY_PERFORMANCE.

Fixes: a4675fbc4a7a (cpufreq: intel_pstate: Replace timers with utilization update callbacks)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Remove PID debugfs when not used

When target state is calculated using get_target_pstate_use_cpu_load(),
PID controller is not used, hence it has no effect on performance.
So don't present debugfs entries to tune PID controller.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Drop boost_iowait flag

The "IOwait boosting" mechanism is only used by the
get_target_pstate_use_cpu_load() governor function and the
boost_iowait flag in pid_params is always set when that function
is in use (and it is never set otherwise). This means that the
boost_iowait flag is in fact redundant and may be dropped.

For this reason, replace the boost_iowait flag check in
intel_pstate_update_util() with an equivalent check against
pstate_funcs.get_target_pstate and drop that flag.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Fix struct pstate_adjust_policy kerneldoc

It looks like the name of struct pstate_adjust_policy was updated
without updating its kerneldoc comment accordingly, so fix that
mistake.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Proportional algorithm for Atom

The PID algorithm used by the intel_pstate driver tends to drive
performance to the minimum for workloads with utilization below the
setpoint, which is undesirable, so replace it with a modified
"proportional" algorithm on Atom.

The new algorithm will set the new P-state to be 1.25 times the
available maximum times the (frequency-invariant) utilization during
the previous sampling period except when the target P-state computed
this way is lower than the average P-state during the previous
sampling period. In the latter case, it will increase the target by
50% of the difference between it and the average P-state to prevent
performance from dropping down too fast in some cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

cpufreq: intel_pstate: Clarify comment in get_target_pstate_use_performance()

Make the comment explaining the meaning of the perf_scaled variable
in get_target_pstate_use_performance() more straightforward.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Fix unsafe HWP MSR access

This is a requirement that MSR MSR_PM_ENABLE must be set to 0x01 before
reading MSR_HWP_CAPABILITIES on a given CPU. If cpufreq init() is
scheduled on a CPU which is not same as policy->cpu or migrates to a
different CPU before calling msr read for MSR_HWP_CAPABILITIES, it
is possible that MSR_PM_ENABLE was not to set to 0x01 on that CPU.
This will cause GP fault. So like other places in this path
rdmsrl_on_cpu should be used instead of rdmsrl.

Moreover the scope of MSR_HWP_CAPABILITIES is on per thread basis, so it
should be read from the same CPU, for which MSR MSR_HWP_REQUEST is
getting set.

dmesg dump or warning:

[ 22.014488] WARNING: CPU: 139 PID: 1 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x68/0x70
[ 22.014492] unchecked MSR access error: RDMSR from 0x771
[ 22.014493] Modules linked in:
[ 22.014507] CPU: 139 PID: 1 Comm: swapper/0 Not tainted 4.7.5+ #1
...
...
[ 22.014516] Call Trace:
[ 22.014542] [<ffffffff813d7dd1>] dump_stack+0x63/0x82
[ 22.014558] [<ffffffff8107bc8b>] __warn+0xcb/0xf0
[ 22.014561] [<ffffffff8107bcff>] warn_slowpath_fmt+0x4f/0x60
[ 22.014563] [<ffffffff810676f8>] ex_handler_rdmsr_unsafe+0x68/0x70
[ 22.014564] [<ffffffff810677d9>] fixup_exception+0x39/0x50
[ 22.014604] [<ffffffff8102e400>] do_general_protection+0x80/0x150
[ 22.014610] [<ffffffff817f9ec8>] general_protection+0x28/0x30
[ 22.014635] [<ffffffff81687940>] ? get_target_pstate_use_performance+0xb0/0xb0
[ 22.014642] [<ffffffff810600c7>] ? native_read_msr+0x7/0x40
[ 22.014657] [<ffffffff81688123>] intel_pstate_hwp_set+0x23/0x130
[ 22.014660] [<ffffffff81688406>] intel_pstate_set_policy+0x1b6/0x340
[ 22.014662] [<ffffffff816829bb>] cpufreq_set_policy+0xeb/0x2c0
[ 22.014664] [<ffffffff81682f39>] cpufreq_init_policy+0x79/0xe0
[ 22.014666] [<ffffffff81682cb0>] ? cpufreq_update_policy+0x120/0x120
[ 22.014669] [<ffffffff816833a6>] cpufreq_online+0x406/0x820
[ 22.014671] [<ffffffff8168381f>] cpufreq_add_dev+0x5f/0x90
[ 22.014717] [<ffffffff81530ac8>] subsys_interface_register+0xb8/0x100
[ 22.014719] [<ffffffff816821bc>] cpufreq_register_driver+0x14c/0x210
[ 22.014749] [<ffffffff81fe1d90>] intel_pstate_init+0x39d/0x4d5
[ 22.014751] [<ffffffff81fe13f2>] ? cpufreq_gov_dbs_init+0x12/0x12

Cc: 4.3+ <stable@vger.kernel.org> # 4.3+
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Add io_boost trace

Add io_boost percent to current pstate_sample tracepoint.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Use IOWAIT flag in Atom algorithm

Modify the P-state selection algorithm for Atom processors to use
the new SCHED_CPUFREQ_IOWAIT flag instead of the questionable
get_cpu_iowait_time_us() function.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

intel_pstate: constify local structures

For structure types defined in the same file or local header files, find
top-level static structure declarations that have the following
properties:
1. Never reassigned.
2. Address never taken
3. Not passed to a top-level macro call
4. No pointer or array-typed field passed to a function or stored in a
variable.
Declare structures having all of these properties as const.

Done using Coccinelle.
Based on a suggestion by Joe Perches <joe@perches.com>.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq / sched: Pass flags to cpufreq_update_util()

It is useful to know the reason why cpufreq_update_util() has just
been called and that can be passed as flags to cpufreq_update_util()
and to the ->func() callback in struct update_util_data. However,
doing that in addition to passing the util and max arguments they
already take would be clumsy, so avoid it.

Instead, use the observation that the schedutil governor is part
of the scheduler proper, so it can access scheduler data directly.
This allows the util and max arguments of cpufreq_update_util()
and the ->func() callback in struct update_util_data to be replaced
with a flags one, but schedutil has to be modified to follow.

Thus make the schedutil governor obtain the CFS utilization
information from the scheduler and use the "RT" and "DL" flags
instead of the special utilization value of ULONG_MAX to track
updates from the RT and DL sched classes. Make it non-modular
too to avoid having to export scheduler variables to modules at
large.

Next, update all of the other users of cpufreq_update_util()
and the ->func() callback in struct update_util_data accordingly.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

cpufreq: intel_pstate: Add more out-of-band IDs

Add Skylake-X and Broadwell-X IDs for out-of-band (OBB) control of
P-States.

For these processors, if MSR_MISC_PWR_MGMT BIT(8) == 1, then the
Intel P-State driver should exit as OS can't control P-States.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw : Subject/changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: intel_pstate: Check cpuid for MSR_HWP_INTERRUPT

The MSR MSR_HWP_INTERRUPT is valid only when CPUID.06H:EAX[8] = 1, so
check for feature before accessing this MSR.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

intel_pstate: Update cpu_frequency tracepoint every time

Currently, intel_pstate only updates the cpu_frequency tracepoint
if the new P-state to set is different from the current one, but
that causes powertop to report 100% idle on an 100% loaded system
sometimes.

Prevent that from happening by updating the cpu_frequency tracepoint
every time intel_pstate_update_pstate() is called.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>-

cpufreq: intel_pstate: clean remnant struct element

When I was working with the Intel P state driver I came across a
remnant struct element that is no longer needed after the function
intel_pstate_calc_freq() was retired.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate()

If MSR_CONFIG_TDP_CONTROL is locked, we currently try to address some
MSR 0x80000648 or so. Mask out the relevant level bits 0 and 1.

Found while running over the Jailhouse hypervisor which became upset
about this strange MSR index.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 4.4+ <stable@vger.kernel.org> # 4.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>