linux-stable.git/drivers/devfreq, branch v4.19.92

PM / devfreq: Lock devfreq in trans_stat_show

2019-12-17T19:35:03+00:00

commit 2abb0d5268ae7b5ddf82099b1f8d5aa8414637d4 upstream.

There is no locking in this sysfs show function so stats printing can
race with a devfreq_update_status called as part of freq switching or
with initialization.

Also add an assert in devfreq_update_status to make it clear that lock
must be held by caller.

Fixes: 39688ce6facd ("PM / devfreq: account suspend/resume for stats")
Cc: stable@vger.kernel.org
Signed-off-by: Leonard Crestez 
Reviewed-by: Matthias Kaehlcke 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Fix kernel oops on governor module load

2019-12-01T08:17:46+00:00

commit 7544fd7f384591038646d3cd9efb311ab4509e24 upstream.

A bit unexpectedly (but still documented), request_module may
return a positive value, in case of a modprobe error.
This is currently causing issues in the devfreq framework.

When a request_module exits with a positive value, we currently
return that via ERR_PTR. However, because the value is positive,
it's not a ERR_VALUE proper, and is therefore treated as a
valid struct devfreq_governor pointer, leading to a kernel oops.

Fix this by returning -EINVAL if request_module returns a positive
value.

Fixes: b53b0128052ff ("PM / devfreq: Fix static checker warning in try_then_request_governor")
Signed-off-by: Ezequiel Garcia 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Cc: Nobuhiro Iwamatsu 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Fix static checker warning in try_then_request_governor

2019-11-24T07:21:07+00:00

[ Upstream commit b53b0128052ffd687797d5f4deeb76327e7b5711 ]

The patch 23c7b54ca1cd: "PM / devfreq: Fix devfreq_add_device() when
drivers are built as modules." leads to the following static checker
warning:

    drivers/devfreq/devfreq.c:1043 governor_store()
    warn: 'governor' can also be NULL

The reason is that the try_then_request_governor() function returns both
error pointers and NULL. It should just return error pointers, so fix
this by returning a ERR_PTR to the error intead of returning NULL.

Fixes: 23c7b54ca1cd ("PM / devfreq: Fix devfreq_add_device() when drivers are built as modules.")
Reported-by: Dan Carpenter 
Signed-off-by: Enric Balletbo i Serra 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin

PM / devfreq: stopping the governor before device_unregister()

2019-11-24T07:19:36+00:00

[ Upstream commit 2f061fd0c2d852e32e03a903fccd810663c5c31e ]

device_release() is freeing the resources before calling the device
specific release callback which is, in the case of devfreq, stopping
the governor.

It is a problem as some governors are using the device resources. e.g.
simpleondemand which is using the devfreq deferrable monitoring work. If it
is not stopped before the resources are freed, it might lead to a use after
free.

Signed-off-by: Vincent Donnefort 
Reviewed-by: John Einar Reitan 
[cw00.choi: Fix merge conflict]
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin

PM / devfreq: Fix handling of min/max_freq == 0

2019-11-24T07:19:35+00:00

[ Upstream commit df5cf4a36178c5d4f2b8b9469cb2f722e64cd102 ]

Commit ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when adding the
devfreq device") initializes df->min/max_freq with the min/max OPP when
the device is added. Later commit f1d981eaecf8 ("PM / devfreq: Use the
available min/max frequency") adds df->scaling_min/max_freq and the
following to the frequency adjustment code:

  max_freq = MIN(devfreq->scaling_max_freq, devfreq->max_freq);

With the current handling of min/max_freq this is incorrect:

Even though df->max_freq is now initialized to a value != 0 user space
can still set it to 0, in this case max_freq would be 0 instead of
df->scaling_max_freq as intended. In consequence the frequency adjustment
is not performed:

  if (max_freq && freq > max_freq) {
	freq = max_freq;

To fix this set df->min/max freq to the min/max OPP in max/max_freq_store,
when the user passes a value of 0. This also prevents df->max_freq from
being set below the min OPP when df->min_freq is 0, and similar for
min_freq. Since it is now guaranteed that df->min/max_freq can't be 0 the
checks for this case can be removed.

Fixes: f1d981eaecf8 ("PM / devfreq: Use the available min/max frequency")
Signed-off-by: Matthias Kaehlcke 
Reviewed-by: Brian Norris 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin

PM / devfreq: Fix devfreq_add_device() when drivers are built as modules.

2019-11-24T07:19:34+00:00

[ Upstream commit 23c7b54ca1cd1797ef39169ab85e6d46f1c2d061 ]

When the devfreq driver and the governor driver are built as modules,
the call to devfreq_add_device() or governor_store() fails because the
governor driver is not loaded at the time the devfreq driver loads. The
devfreq driver has a build dependency on the governor but also should
have a runtime dependency. We need to make sure that the governor driver
is loaded before the devfreq driver.

This patch fixes this bug by adding a try_then_request_governor()
function. First tries to find the governor, and then, if it is not found,
it requests the module and tries again.

Fixes: 1b5c1be2c88e (PM / devfreq: map devfreq drivers to governor using name)
Signed-off-by: Enric Balletbo i Serra 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin

PM / devfreq: tegra: Fix kHz to Hz conversion

2019-10-11T16:20:46+00:00

commit 62bacb06b9f08965c4ef10e17875450490c948c0 upstream.

The kHz to Hz is incorrectly converted in a few places in the code,
this results in a wrong frequency being calculated because devfreq core
uses OPP frequencies that are given in Hz to clamp the rate, while
tegra-devfreq gives to the core value in kHz and then it also expects to
receive value in kHz from the core. In a result memory freq is always set
to a value which is close to ULONG_MAX because of the bug. Hence the EMC
frequency is always capped to the maximum and the driver doesn't do
anything useful. This patch was tested on Tegra30 and Tegra124 SoC's, EMC
frequency scaling works properly now.

Cc:  # 4.14+
Tested-by: Steev Klimaszewski 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Dmitry Osipenko 
Acked-by: Thierry Reding 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: passive: fix compiler warning

2019-10-05T11:09:59+00:00

[ Upstream commit 0465814831a926ce2f83e8f606d067d86745234e ]

The recent commit of
PM / devfreq: passive: Use non-devm notifiers
had incurred compiler warning, "unused variable 'dev'".

Reported-by: Stephen Rothwell 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin

PM / devfreq: exynos-bus: Correct clock enable sequence

2019-10-05T11:09:48+00:00

[ Upstream commit 2c2b20e0da89c76759ee28c6824413ab2fa3bfc6 ]

Regulators should be enabled before clocks to avoid h/w hang. This
require change in exynos_bus_probe() to move exynos_bus_parse_of()
after exynos_bus_parent_parse_of() and change in error handling.
Similar change is needed in exynos_bus_exit() where clock should be
disabled before regulators.

Signed-off-by: Kamil Konieczny 
Acked-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin

PM / devfreq: passive: Use non-devm notifiers

2019-10-05T11:09:48+00:00

[ Upstream commit 0ef7c7cce43f6ecc2b96d447e69b2900a9655f7c ]

The devfreq passive governor registers and unregisters devfreq
transition notifiers on DEVFREQ_GOV_START/GOV_STOP using devm wrappers.

If devfreq itself is registered with devm then a warning is triggered on
rmmod from devm_devfreq_unregister_notifier. Call stack looks like this:

	devm_devfreq_unregister_notifier+0x30/0x40
	devfreq_passive_event_handler+0x4c/0x88
	devfreq_remove_device.part.8+0x6c/0x9c
	devm_devfreq_dev_release+0x18/0x20
	release_nodes+0x1b0/0x220
	devres_release_all+0x78/0x84
	device_release_driver_internal+0x100/0x1c0
	driver_detach+0x4c/0x90
	bus_remove_driver+0x7c/0xd0
	driver_unregister+0x2c/0x58
	platform_driver_unregister+0x10/0x18
	imx_devfreq_platdrv_exit+0x14/0xd40 [imx_devfreq]

This happens because devres_release_all will first remove all the nodes
into a separate todo list so the nested devres_release from
devm_devfreq_unregister_notifier won't find anything.

Fix the warning by calling the non-devm APIS for frequency notification.
Using devm wrappers is not actually useful for a governor anyway: it
relies on the devfreq core to correctly match the GOV_START/GOV_STOP
notifications.

Fixes: 996133119f57 ("PM / devfreq: Add new passive governor")
Signed-off-by: Leonard Crestez 
Acked-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin