linux-stable.git/drivers/cpufreq, branch v4.4.271

cpufreq: powernow-k8: pass policy rather than use cpufreq_cpu_get()

2021-01-17T12:55:13+00:00

commit 943bdd0cecad06da8392a33093230e30e501eccc upstream.

Currently there is an unlikely case where cpufreq_cpu_get() returns a
NULL policy and this will cause a NULL pointer dereference later on.

Fix this by passing the policy to transition_frequency_fidvid() from
the caller and hence eliminating the need for the cpufreq_cpu_get()
and cpufreq_cpu_put().

Thanks to Viresh Kumar for suggesting the fix.

Addresses-Coverity: ("Dereference null return")
Fixes: b43a7ffbf33b ("cpufreq: Notify all policy->cpus in cpufreq_notify_transition()")
Suggested-by: Viresh Kumar 
Signed-off-by: Colin Ian King 
Acked-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: scpi: Add missing MODULE_ALIAS

2020-12-29T12:42:38+00:00

[ Upstream commit c0382d049d2def37b81e907a8b22661a4a4a6eb5 ]

This patch adds missing MODULE_ALIAS for automatic loading of this cpufreq
driver when it is compiled as an external module.

Signed-off-by: Pali Rohár 
Fixes: 8def31034d033 ("cpufreq: arm_big_little: add SCPI interface driver")
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: loongson1: Add missing MODULE_ALIAS

2020-12-29T12:42:38+00:00

[ Upstream commit b9acab091842ca8b288882798bb809f7abf5408a ]

This patch adds missing MODULE_ALIAS for automatic loading of this cpufreq
driver when it is compiled as an external module.

Signed-off-by: Pali Rohár 
Fixes: a0a22cf14472f ("cpufreq: Loongson1: Add cpufreq driver for Loongson1B")
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: highbank: Add missing MODULE_DEVICE_TABLE

2020-12-29T12:42:38+00:00

[ Upstream commit 9433777a6e0aae27468d3434b75cd51bb88ff711 ]

This patch adds missing MODULE_DEVICE_TABLE definition which generates
correct modalias for automatic loading of this cpufreq driver when it is
compiled as an external module.

Signed-off-by: Pali Rohár 
Fixes: 6754f556103be ("cpufreq / highbank: add support for highbank cpufreq")
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

acpi-cpufreq: Honor _PSD table setting on new AMD CPUs

2020-11-10T09:22:15+00:00

commit 5368512abe08a28525d9b24abbfc2a72493e8dba upstream.

acpi-cpufreq has a old quirk that overrides the _PSD table supplied by
BIOS on AMD CPUs. However the _PSD table of new AMD CPUs (Family 19h+)
now accurately reports the P-state dependency of CPU cores. Hence this
quirk needs to be fixed in order to support new CPUs' frequency control.

Fixes: acd316248205 ("acpi-cpufreq: Add quirk to disable _PSD usage on all AMD CPUs")
Signed-off-by: Wei Huang 
[ rjw: Subject edit ]
Cc: 3.10+  # 3.10+
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_reboot_notifier

2020-10-29T08:03:06+00:00

[ Upstream commit a2d0230b91f7e23ceb5d8fb6a9799f30517ec33a ]

The patch avoids allocating cpufreq_policy on stack hence fixing frame
size overflow in 'powernv_cpufreq_reboot_notifier':

  drivers/cpufreq/powernv-cpufreq.c: In function powernv_cpufreq_reboot_notifier:
  drivers/cpufreq/powernv-cpufreq.c:906:1: error: the frame size of 2064 bytes is larger than 2048 bytes

Fixes: cf30af76 ("cpufreq: powernv: Set the cpus to nominal frequency during reboot/kexec")
Signed-off-by: Srikar Dronamraju 
Reviewed-by: Daniel Axtens 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200922080254.41497-1-srikar@linux.vnet.ibm.com
Signed-off-by: Sasha Levin

x86/cpu: Rename cpu_data.x86_mask to cpu_data.x86_stepping

2020-06-11T07:21:40+00:00

commit b399151cb48db30ad1e0e93dd40d68c6d007b637 upstream.

x86_mask is a confusing name which is hard to associate with the
processor's stepping.

Additionally, correct an indent issue in lib/cpu.c.

[ Backport by Mark Gross to simplify the SRBDS backport ]

Signed-off-by: Jia Zhang 
[ Updated it to more recent kernels. ]
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: bp@alien8.de
Cc: tony.luck@intel.com
Link: http://lkml.kernel.org/r/1514771530-70829-1-git-send-email-qianyue.zj@alibaba-inc.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

Revert "cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT"

2020-05-10T08:26:24+00:00

commit 68e80dae09033d778b98dc88e5bfe8fdade188e5 upstream.

Earlier, when the struct freq-attr was used to represent governor
attributes, the standard cpufreq show/store sysfs attribute callbacks
were applied to the governor tunable attributes and they always acquire
the policy->rwsem lock before carrying out the operation.  That could
have resulted in an ABBA deadlock if governor tunable attributes are
removed under policy->rwsem while one of them is being accessed
concurrently (if sysfs attributes removal wins the race, it will wait
for the access to complete with policy->rwsem held while the attribute
callback will block on policy->rwsem indefinitely).

We attempted to address this issue by dropping policy->rwsem around
governor tunable attributes removal (that is, around invocations of the
->governor callback with the event arg equal to CPUFREQ_GOV_POLICY_EXIT)
in cpufreq_set_policy(), but that opened up race conditions that had not
been possible with policy->rwsem held all the time.

The previous commit, "cpufreq: governor: New sysfs show/store callbacks
for governor tunables", fixed the original ABBA deadlock by adding new
governor specific show/store callbacks.

We don't have to drop rwsem around invocations of governor event
CPUFREQ_GOV_POLICY_EXIT anymore, and original fix can be reverted now.

Fixes: 955ef4833574 (cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT)
Signed-off-by: Viresh Kumar 
Reported-by: Juri Lelli 
Tested-by: Juri Lelli 
Tested-by: Shilpasri G Bhat 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: Register drivers only after CPU devices have been registered

2020-01-04T12:34:16+00:00

[ Upstream commit 46770be0cf94149ca48be87719bda1d951066644 ]

The cpufreq core heavily depends on the availability of the struct
device for CPUs and if they aren't available at the time cpufreq driver
is registered, we will never succeed in making cpufreq work.

This happens due to following sequence of events:

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

... at a later point of time

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

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

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

Reported-by: Bjorn Andersson 
Co-developed-by: Amit Kucheria 
Signed-off-by: Viresh Kumar 
Tested-by: Amit Kucheria 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cpufreq: Add NULL checks to show() and store() methods of cpufreq

2019-11-28T17:26:19+00:00

commit e6e8df07268c1f75dd9215536e2ce4587b70f977 upstream.

Add NULL checks to show() and store() in cpufreq.c to avoid attempts
to invoke a NULL callback.

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

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

This bug was found in linux 4.19.

Signed-off-by: Kai Shen 
Reported-by: Feilong Lin 
Reviewed-by: Feilong Lin 
Acked-by: Viresh Kumar 
[ rjw: Subject & changelog ]
Cc: All applicable 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman