Pull cpufreq driver fixes for v5.1 from Viresh Kumar:
"This pull request contains minor fixes for ap806 and kryo cpufreq
drivers (Julia Lawall and Viresh Kumar)."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: kryo: Release OPP tables on module removal
cpufreq: ap806: add missing of_node_put after of_device_is_available
Commit 5ad7346b4a ("cpufreq: kryo: Add module remove and exit") made
it possible to build the kryo cpufreq driver as a module, but it failed
to release all the resources, i.e. OPP tables, when the module is
unloaded.
This patch fixes it by releasing the OPP tables, by calling
dev_pm_opp_put_supported_hw() for them, from the
qcom_cpufreq_kryo_remove() routine. The array of pointers to the OPP
tables is also allocated dynamically now in qcom_cpufreq_kryo_probe(),
as the pointers will be required while releasing the resources.
Compile tested only.
Cc: 4.18+ <stable@vger.kernel.org> # v4.18+
Fixes: 5ad7346b4a ("cpufreq: kryo: Add module remove and exit")
Reviewed-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Add an of_node_put when a tested device node is not available.
The semantic patch that fixes this problem is as follows
(http://coccinelle.lip6.fr):
// <smpl>
@@
identifier f;
local idexpression e;
expression x;
@@
e = f(...);
... when != of_node_put(e)
when != x = e
when != e = x
when any
if (<+...of_device_is_available(e)...+>) {
... when != of_node_put(e)
(
return e;
|
+ of_node_put(e);
return ...;
)
}
// </smpl>
Fixes: f525a67053 ("cpufreq: ap806: add cpufreq driver for Armada 8K")
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
There is some rare cases where CPB (and possibly IDA) are missing on
processors.
This is the case fixed by commit f7f3dc00f6 ("x86/cpu/AMD: Fix
erratum 1076 (CPB bit)") and following.
In such context, the boost status isn't reported by
/sys/devices/system/cpu/cpufreq/boost.
This commit is about printing a message to report that the CPU
doesn't expose the boost capabilities.
This message could help debugging platforms hit by this phenomena.
Signed-off-by: Erwan Velu <e.velu@criteo.com>
[ rjw: Change the message text somewhat ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The invocation of the ->setpolicy() cpufreq driver callback should
be equivalent to calling cpufreq_governor_limits(policy) for drivers
with internal governors, but in fact it isn't so, because the
temporary new_policy object is passed to it instead of the updated
policy.
That is a bit confusing, so make cpufreq_set_policy() pass the
updated policy to the driver ->setpolicy() callback.
No intentional changes of behavior.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Remove the redundant "cpufreq:" prefix from two debug messages in
cpufreq_set_policy().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
In cpufreq_update_policy(), instead of updating new_policy.cur
separately, which is kind of confusing, because cpufreq_set_policy()
doesn't take that value into account directly anyway, make the copy
of the existing policy after calling cpufreq_update_current_freq().
No intentional changes of behavior.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Add kerneldoc comments describing cpufreq_set_policy() and
cpufreq_update_policy() as they have not been properly documented
so far and they really need to be documented.
While at it, fix white space around the cpufreq_set_policy() header.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
This issue was detected with the help of Coccinelle. So
change the order of function calls to fix it.
Fixes: 1690d8bb91 (cpufreq: scpi/scmi: Fix freeing of dynamic OPPs)
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull cpufreq drivers material for v5.1 from Viresh Kumar:
"This contains:
- Minor cleanups for pcc, longhaul, powerenv and speedstep drivers (Yangtao Li).
- Moving configuration data out of mach directory for davinci (Bartosz Golaszewski)."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: davinci: move configuration to include/linux/platform_data
cpufreq: speedstep: convert BUG() to BUG_ON()
cpufreq: powernv: fix missing check of return value in init_powernv_pstates()
cpufreq: longhaul: remove unneeded semicolon
cpufreq: pcc-cpufreq: remove unneeded semicolon
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 a5a0809bc5 ("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>
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>
After commit 1a4fe38add ("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>
Hisilicon chips do not support delivered performance counter register
and reference performance counter register. But the platform can
calculate the real performance using its own method. We reuse the
desired performance register to store the real performance calculated by
the platform. After the platform finished the frequency adjust, it gets
the real performance and writes it into desired performance register. Os
can use it to calculate the real frequency.
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
[ rjw: Drop unnecessary braces ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The header containing the configuration structure for davinci cpufreq
driver lives in mach-davinci/include/mach/. This is fine for now but
if we want to make davinci part of the multi_v5 build, no code external
to mach-davinci should include machine-specific headers.
Move the configuration structure to include/linux/platform_data.
While we're at it: convert the GPL-2.0 boilerplate to a proper SPDX
license identifier.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
To fix coccinelle WARNING.
WARNING: Use BUG_ON instead of if condition followed by BUG.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
kmalloc() could fail, so insert a check of its return value. And
if it fails, returns -ENOMEM.
And remove (struct pstate_idx_revmap_data *) to fix coccinelle WARNING
by the way.
WARNING: casting value returned by memory allocation function to (struct
pstate_idx_revmap_data *) is useless.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Double NOT (!!) operation is normally done to convert a non-zero value
to 1 and keep zero as is, but that isn't the requirement in this case.
All we wanted was to make sure that only one of the two routines isn't
set, i.e. either both function pointers are set or both are unset.
This can be done with a single NOT (!) operation as well.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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>
Pull ARM cpufreq driver updates for v5.1 from Viresh Kumar:
"This pull request contains following changes:
- New Armada 8k cpufreq driver (Gregory CLEMENT).
- qcom driver cleanups (Amit Kucheria, Taniya Das, Yangtao Li).
- s5pv210 driver cleanup (Paweł Chmiel).
- tegra driver cleanup (Yangtao Li).
- Minor update to MAINTAINERS file (Baruch Siach)."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: qcom-hw: Register an Energy Model
cpufreq: qcom: Read voltage LUT and populate OPP
cpufreq: qcom-hw: Move to device_initcall
cpufreq: tegra124: add missing of_node_put()
cpufreq: qcom-kryo: make some variables static
MAINTAINERS: Update the active pm tree for ARM
cpufreq: ap806: add cpufreq driver for Armada 8K
MAINTAINERS: add new entries for Armada 8K cpufreq driver
cpufreq: s5pv210: Defer probe if getting regulators fail
MAINTAINERS: use common indentation
PM / OPP: Introduce a power estimation helper
PM / OPP: Remove unused parameter of _generic_set_opp_clk_only()
Implement the light-weight tear down and bring up helpers to reduce the
amount of work to do on CPU offline/online operation.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The cpufreq core doesn't remove the cpufreq policy anymore on CPU
offline operation, rather that happens when the CPU device gets
unregistered from the kernel. This allows faster recovery when the CPU
comes back online. This is also very useful during system wide
suspend/resume where we offline all non-boot CPUs during suspend and
then bring them back on resume.
This commit takes the same idea a step ahead to allow drivers to do
light weight tear-down and bring-up during CPU offline and online
operations.
A new set of callbacks is introduced, online/offline(). online() gets
called when the first CPU of an inactive policy is brought up and
offline() gets called when all the CPUs of a policy are offlined.
The existing init/exit() callback get called on policy
creation/destruction. They also get called instead of online/offline()
callbacks if the online/offline() callbacks aren't provided.
This also moves around some code to get executed only for the new-policy
case going forward.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Try and register an Energy Model from qcom-cpufreq-hw to allow
interested sub-systems like the task scheduler to use the provided
information.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
[ Viresh: Rebased over cpufreq related changes ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Add support to read the voltage look up table and populate OPP for all
corresponding CPUS for consumers like the energy model could use the
frequency and voltage from the OPP tables. Also update the logic to not add
duplicate OPPs.
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Taniya Das <tdas@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
subsys_initcall causes problems registering the driver as a thermal
cooling device.
If "faster boot" is the main reason for doing subsys_initcall, this
should be handled in the bootloader or another boot constraint
framework.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Add cpufreq driver for Marvell AP-806 found on Aramda 8K.
The AP-806 has DFS (Dynamic Frequency Scaling) with coupled
clock domain for two clusters, so this driver will directly
use generic cpufreq-dt driver as backend.
Based on the work of Omri Itach <omrii@marvell.com>.
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
of_cpu_device_node_get() will increase the refcount of device_node,
it is necessary to call of_node_put() at the end to release the
refcount.
Fixes: 9eb15dbbfa ("cpufreq: Add cpufreq driver for Tegra124")
Cc: <stable@vger.kernel.org> # 4.4+
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The variables are local to the source and do not
need to be in global scope, so make them static.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
There is possibility, that when probing driver, regulators are not yet
initialized. In this case we should return EPROBE_DEFER and wait till
they're initialized, since they're required currently for cpufreq driver
to work. Also move regulator initialization code at beginning of probe,
so we can defer as fast as posibble.
Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
It is possible for cpufreq_stats_clear_table() and
cpufreq_stats_record_transition() to get called concurrently and they
will try to update same variables simultaneously and may lead to
corruption of data.
Prevent that with the help of existing spinlock.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Freq attribute for "trans_table" is defined right after its callback
(without any blank line between them), but the others are defined
separately later on. Keep this consistent and define all attributes
right after their callbacks.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.
This allows removal of boiler plate code from the driver.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.
This allows removal of boiler plate code from the driver.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.
This allows removal of boiler plate code from the driver.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.
This allows removal of boiler plate code from the driver.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.
This allows removal of boiler plate code from the driver.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Use the CPUFREQ_IS_COOLING_DEV flag to allow cpufreq core to
automatically register as a thermal cooling device.
This allows removal of boiler plate code from the driver.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add the CPUFREQ_IS_COOLING_DEV flag to allow the cpufreq core to
auto-register the driver as a cooling device.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
All cpufreq drivers do similar things to register as a cooling device.
Provide a cpufreq driver flag so drivers can just ask the cpufreq core
to register the cooling device on their behalf. This allows us to get
rid of duplicated code in the drivers.
In order to allow this, we add a struct thermal_cooling_device pointer
to struct cpufreq_policy so that drivers don't need to store it in a
private data structure.
Suggested-by: Stephen Boyd <swboyd@chromium.org>
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The CPU cooling driver (cpu_cooling.c) allows the platform's cpufreq
driver to register as a cooling device and cool down the platform by
throttling the CPU frequency. In order to be able to auto-register a
cpufreq driver as a cooling device from the cpufreq core, we need access
to code inside cpu_cooling.c which, in turn, accesses code inside
thermal core.
CPU_FREQ is a bool while THERMAL is tristate. In some configurations
(e.g. allmodconfig), CONFIG_THERMAL ends up as a module while
CONFIG_CPU_FREQ is compiled in. This leads to following error:
drivers/cpufreq/cpufreq.o: In function `cpufreq_offline':
cpufreq.c:(.text+0x407c): undefined reference to `cpufreq_cooling_unregister'
drivers/cpufreq/cpufreq.o: In function `cpufreq_online':
cpufreq.c:(.text+0x70c0): undefined reference to `of_cpufreq_cooling_register'
Given that platforms using CPU_THERMAL usually want it compiled-in so it
is available early in boot, make CPU_THERMAL depend on THERMAL being
compiled-in instead of allowing it to be a module.
As a result of this change, get rid of the ugly (!CPU_THERMAL ||
THERMAL) dependency in all cpufreq drivers using CPU_THERMAL.
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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>
One of the more common cases of allocation size calculations is
finding the size of a structure that has a zero-sized array at
the end, along with memory for some number of elements for that
array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we
can now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The local variable "new_policy" hasn't been used in the error path of
cpufreq_online() since commit f9f41e3ef9 (cpufreq: Remove policy
create/remove notifiers). Don't update it in that error path.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The scmi-cpufreq driver calls the arch_set_freq_scale() callback on
frequency changes to provide scale-invariant load-tracking signals to
the scheduler. However, in the slow path, it does so while specifying
the current and max frequencies in different units, hence resulting in a
broken freq_scale factor.
Fix this by passing all frequencies in KHz, as stored in the CPUFreq
frequency table.
Fixes: 99d6bdf338 (cpufreq: add support for CPU DVFS based on SCMI message protocol)
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: 4.17+ <stable@vger.kernel.org> # v4.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpuinfo_cur_freq gets current CPU frequency as detected by hardware
while scaling_cur_freq last known CPU frequency. Some platforms may not
allow checking the CPU frequency of an offline CPU or the associated
resources may have been released via cpufreq_exit when the CPU gets
offlined, in which case the policy would have been invalidated already.
If we attempt to get current frequency from the hardware, it may result
in hang or crash.
For example on Juno, I see:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188
[0000000000000188] pgd=0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 5 PID: 4202 Comm: cat Not tainted 4.20.0-08251-ga0f2c0318a15-dirty #87
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform
pstate: 40000005 (nZcv daif -PAN -UAO)
pc : scmi_cpufreq_get_rate+0x34/0xb0
lr : scmi_cpufreq_get_rate+0x34/0xb0
Call trace:
scmi_cpufreq_get_rate+0x34/0xb0
__cpufreq_get+0x34/0xc0
show_cpuinfo_cur_freq+0x24/0x78
show+0x40/0x60
sysfs_kf_seq_show+0xc0/0x148
kernfs_seq_show+0x44/0x50
seq_read+0xd4/0x480
kernfs_fop_read+0x15c/0x208
__vfs_read+0x60/0x188
vfs_read+0x94/0x150
ksys_read+0x6c/0xd8
__arm64_sys_read+0x24/0x30
el0_svc_common+0x78/0x100
el0_svc_handler+0x38/0x78
el0_svc+0x8/0xc
---[ end trace 3d1024e58f77f6b2 ]---
So fix the issue by checking if the policy is invalid early in
__cpufreq_get before attempting to get the current frequency.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
