linux-stable.git/drivers/cpufreq, branch v5.4.38

cpufreq: powernv: Fix use-after-free

2020-04-17T08:50:22+00:00

commit d0a72efac89d1c35ac55197895201b7b94c5e6ef upstream.

The cpufreq driver has a use-after-free that we can hit if:

a) There's an OCC message pending when the notifier is registered, and
b) The cpufreq driver fails to register with the core.

When a) occurs the notifier schedules a workqueue item to handle the
message. The backing work_struct is located on chips[].throttle and
when b) happens we clean up by freeing the array. Once we get to
the (now free) queued item and the kernel crashes.

Fixes: c5e29ea7ac14 ("cpufreq: powernv: Fix bugs in powernv_cpufreq_{init/exit}")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Oliver O'Halloran 
Reviewed-by: Gautham R. Shenoy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200206062622.28235-1-oohall@gmail.com
Signed-off-by: Greg Kroah-Hartman

cpufreq: imx6q: fix error handling

2020-04-17T08:50:03+00:00

[ Upstream commit 3646f50a3838c5949a89ecbdb868497cdc05b8fd ]

When speed checking failed, direclty jumping to put_node label
is not correct. Need jump to out_free_opp to avoid resources leak.

Fixes: 2733fb0d0699 ("cpufreq: imx6q: read OCOTP through nvmem for imx6ul/imx6ull")
Signed-off-by: Peng Fan 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: imx6q: Fixes unwanted cpu overclocking on i.MX6ULL

2020-04-17T08:50:00+00:00

[ Upstream commit 36eb7dc1bd42fe5f850329c893768ff89b696fba ]

imx6ul_opp_check_speed_grading is called for both i.MX6UL and i.MX6ULL.
Since the i.MX6ULL was introduced to a separate ocotp compatible node
later, it is possible that the i.MX6ULL has also dtbs with
"fsl,imx6ull-ocotp". On a system without nvmem-cell speed grade a
missing check on this node causes a driver fail without considering
the cpu speed grade.

This patch prevents unwanted cpu overclocking on i.MX6ULL with compatible
node "fsl,imx6ull-ocotp" in old dtbs without nvmem-cell speed grade.

Fixes: 2733fb0d0699 ("cpufreq: imx6q: read OCOTP through nvmem for imx6ul/imx6ull")
Signed-off-by: Christoph Niedermaier 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: Fix policy initialization for internal governor drivers

2020-03-05T15:43:44+00:00

commit f5739cb0b56590d68d8df8a44659893b6d0084c3 upstream.

Before commit 1e4f63aecb53 ("cpufreq: Avoid creating excessively
large stack frames") the initial value of the policy field in struct
cpufreq_policy set by the driver's ->init() callback was implicitly
passed from cpufreq_init_policy() to cpufreq_set_policy() if the
default governor was neither "performance" nor "powersave".  After
that commit, however, cpufreq_init_policy() must take that case into
consideration explicitly and handle it as appropriate, so make that
happen.

Fixes: 1e4f63aecb53 ("cpufreq: Avoid creating excessively large stack frames")
Link: https://lore.kernel.org/linux-pm/39fb762880c27da110086741315ca8b111d781cd.camel@gmail.com/
Reported-by: Artem Bityutskiy 
Cc: 5.4+  # 5.4+
Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar 
Signed-off-by: Greg Kroah-Hartman

cpufreq: Avoid creating excessively large stack frames

2020-02-11T12:35:25+00:00

commit 1e4f63aecb53e48468661e922fc2fa3b83e55722 upstream.

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 
Reported-by: Geert Uytterhoeven 
Cc: 5.4+  # 5.4+
Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar 
Signed-off-by: Greg Kroah-Hartman

cpufreq: Register drivers only after CPU devices have been registered

2019-12-31T15:45:26+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: sun50i: Fix CPU speed bin detection

2019-12-31T15:44:38+00:00

[ Upstream commit c23734487fb44ee16c1b007ba72d793c085e4ec4 ]

I have observed failures to boot on Orange Pi 3, because this driver
determined that my SoC is from the normal bin, but my SoC only works
reliably with the OPP values for the slowest bin.

By querying H6 owners, it was found that e-fuse values found in the wild
are in the range of 1-3, value of 7 was not reported, yet. From this and
from unused defines in BSP code, it can be assumed that meaning of efuse
values on H6 actually is:

- 1 = slowest bin
- 2 = normal bin
- 3 = fastest bin

Vendor code actually treats 0 and 2 as invalid efuse values, but later
treats all invalid values as a normal bin. This looks like a mistake in
bin detection code, that was plastered over by a hack in cpufreq code,
so let's not repeat it here. It probably only works because there are no
SoCs in the wild with efuse value of 0, and fast bin SoCs are made to
use normal bin OPP tables, which is also safe.

Let's play it safe and interpret 0 as the slowest bin, but fix detection
of other bins to match this research. More research will be done before
actual OPP tables are merged.

Fixes: f328584f7bff ("cpufreq: Add sun50i nvmem based CPU scaling driver")
Acked-by: Maxime Ripard 
Signed-off-by: Ondrej Jirman 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: powernv: fix stack bloat and hard limit on number of CPUs

2019-12-17T18:56:26+00:00

commit db0d32d84031188443e25edbd50a71a6e7ac5d1d upstream.

The following build warning occurred on powerpc 64-bit builds:

drivers/cpufreq/powernv-cpufreq.c: In function 'init_chip_info':
drivers/cpufreq/powernv-cpufreq.c:1070:1: warning: the frame size of
1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]

This is with a cross-compiler based on gcc 8.1.0, which I got from:
  https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/

The warning is due to putting 1024 bytes on the stack:

    unsigned int chip[256];

...and it's also undesirable to have a hard limit on the number of
CPUs here.

Fix both problems by dynamically allocating based on num_possible_cpus,
as recommended by Michael Ellerman.

Fixes: 053819e0bf840 ("cpufreq: powernv: Handle throttling due to Pmax capping at chip level")
Signed-off-by: John Hubbard 
Acked-by: Viresh Kumar 
Cc: 4.10+  # 4.10+
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: imx-cpufreq-dt: Correct i.MX8MN's default speed grade value

2019-12-13T07:43:28+00:00

[ Upstream commit af44d180e3de4cb411ce327b147ea3513f0bbbcb ]

i.MX8MN has different speed grade definition compared to
i.MX8MQ/i.MX8MM, when fuses are NOT written, the default
speed_grade should be set to minimum available OPP defined
in DT which is 1.2GHz, the corresponding speed_grade value
should be 0xb.

Fixes: 5b8010ba70d5 ("cpufreq: imx-cpufreq-dt: Add i.MX8MN support")
Signed-off-by: Anson Huang 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

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

2019-11-29T09:10:07+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