thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header

The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY
attribute to receive HFI events from kernel sp

thermal/netlink: Prevent userspace segmentation fault by adjusting UAPI header

The intel-lpmd tool [1], which uses the THERMAL_GENL_ATTR_CPU_CAPABILITY
attribute to receive HFI events from kernel space, encounters a
segmentation fault after commit 1773572863c4 ("thermal: netlink: Add the
commands and the events for the thresholds").

The issue arises because the THERMAL_GENL_ATTR_CPU_CAPABILITY raw value
was changed while intel_lpmd still uses the old value.

Although intel_lpmd can be updated to check the THERMAL_GENL_VERSION and
use the appropriate THERMAL_GENL_ATTR_CPU_CAPABILITY value, the commit
itself is questionable.

The commit introduced a new element in the middle of enum thermal_genl_attr,
which affects many existing attributes and introduces potential risks
and unnecessary maintenance burdens for userspace thermal netlink event
users.

Solve the issue by moving the newly introduced
THERMAL_GENL_ATTR_TZ_PREV_TEMP attribute to the end of the
enum thermal_genl_attr. This ensures that all existing thermal generic
netlink attributes remain unaffected.

Link: https://github.com/intel/intel-lpmd [1]
Fixes: 1773572863c4 ("thermal: netlink: Add the commands and the events for the thresholds")
Signed-off-by: Zhang Rui <[email protected]>
Reviewed-by: Daniel Lezcano <[email protected]>
Link: https://patch.msgid.link/[email protected]
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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thermal/thresholds: Fix uapi header macros leading to a compilation error

The macros giving the direction of the crossing thresholds use the BIT
macro which is not exported to the userspace. Consequ

thermal/thresholds: Fix uapi header macros leading to a compilation error

The macros giving the direction of the crossing thresholds use the BIT
macro which is not exported to the userspace. Consequently when an
userspace program includes the header, it fails to compile.

Replace the macros by their litteral to allow the compilation of
userspace program using this header.

Fixes: 445936f9e258 ("thermal: core: Add user thresholds support")
Signed-off-by: Daniel Lezcano <[email protected]>
Link: https://patch.msgid.link/[email protected]
[ rjw: Add Fixes: ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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thermal: netlink: Add the commands and the events for the thresholds

The thresholds exist but there is no notification neither action code
related to them yet.

These changes implement the netlink f

thermal: netlink: Add the commands and the events for the thresholds

The thresholds exist but there is no notification neither action code
related to them yet.

These changes implement the netlink for the notifications when the
thresholds are crossed, added, deleted or flushed as well as the
commands which allows to get the list of the thresholds, flush them,
add and delete.

Signed-off-by: Daniel Lezcano <[email protected]>
Reviewed-by: Lukasz Luba <[email protected]>
Link: https://patch.msgid.link/[email protected]
[ rjw: Use the thermal_zone guard for locking, subject edit ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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thermal: core: Add user thresholds support

The user thresholds mechanism is a way to have the userspace to tell
the thermal framework to send a notification when a temperature limit
is crossed. Ther

thermal: core: Add user thresholds support

The user thresholds mechanism is a way to have the userspace to tell
the thermal framework to send a notification when a temperature limit
is crossed. There is no id, no hysteresis, just the temperature and
the direction of the limit crossing. That means we can be notified
when a threshold is crossed the way up only, or the way down only or
both ways. That allows to create hysteresis values if it is needed.

A threshold can be added, deleted or flushed. The latter means all
thresholds belonging to a thermal zone will be deleted.

When a threshold is added:

- if the same threshold (temperature and direction) exists, an error
is returned

- if a threshold is specified with the same temperature but a
different direction, the specified direction is added

- if there is no threshold with the same temperature then it is
created

When a threshold is deleted:

- if the same threshold (temperature and direction) exists, it is
deleted

- if a threshold is specified with the same temperature but a
different direction, the specified direction is removed

- if there is no threshold with the same temperature, then an error
is returned

When the threshold are flushed:

- All thresholds related to a thermal zone are deleted

When a threshold is crossed:

- the userspace does not need to know which threshold(s) have been
crossed, it will be notified with the current temperature and the
previous temperature

- if multiple thresholds have been crossed between two updates only
one notification will be send to the userspace, it is pointless to
send a notification per thresholds crossed as the userspace can
handle that easily when it has the temperature delta information

Signed-off-by: Daniel Lezcano <[email protected]>
Link: https://patch.msgid.link/[email protected]
[ rjw: Subject edit, use BIT(0) and BIT(1) in symbol definitions ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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thermal: netlink: Add a new event to notify CPU capabilities change

Add a new netlink event to notify change in CPU capabilities in terms of
performance and efficiency.

Firmware may change CPU capa

thermal: netlink: Add a new event to notify CPU capabilities change

Add a new netlink event to notify change in CPU capabilities in terms of
performance and efficiency.

Firmware may change CPU capabilities as a result of thermal events in the
system or to account for changes in the TDP (thermal design power) level.

This notification type will allow user space to avoid running workloads
on certain CPUs or proactively adjust power limits to avoid future events.

The netlink message consists of a nested attribute
(THERMAL_GENL_ATTR_CPU_CAPABILITY) with three attributes:

* THERMAL_GENL_ATTR_CPU_CAPABILITY_ID (type u32):
-- logical CPU number
* THERMAL_GENL_ATTR_CPU_CAPABILITY_PERFORMANCE (type u32):
-- Scaled performance from 0-1023
* THERMAL_GENL_ATTR_CPU_CAPABILITY_EFFICIENCY (type u32):
-- Scaled efficiency from 0-1023

Reviewed-by: Len Brown <[email protected]>
Signed-off-by: Srinivas Pandruvada <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

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thermal: Fix spelling mistake "disabed" -> "disabled"

There is a spelling mistake in a comment, fix it.

Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Daniel Lezcano <danie

thermal: Fix spelling mistake "disabed" -> "disabled"

There is a spelling mistake in a comment, fix it.

Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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thermal: core: genetlink support for events/cmd/sampling

Initially the thermal framework had a very simple notification
mechanism to send generic netlink messages to the userspace.

The notification

thermal: core: genetlink support for events/cmd/sampling

Initially the thermal framework had a very simple notification
mechanism to send generic netlink messages to the userspace.

The notification function was never called from anywhere and the
corresponding dead code was removed. It was probably a first attempt
to introduce the netlink notification.

At LPC2018, the presentation "Linux thermal: User kernel interface",
proposed to create the notifications to the userspace via a kfifo.

The advantage of the kfifo is the performance. It is usually used from
a 1:1 communication channel where a driver captures data and sends it
as fast as possible to a userspace process.

The drawback is that only one process uses the notification channel
exclusively, thus no other process is allowed to use the channel to
get temperature or notifications.

This patch defines a generic netlink API to discover the current
thermal setup and adds event notifications as well as temperature
sampling. As any genetlink protocol, it can evolve and the versioning
allows to keep the backward compatibility.

In order to prevent the user from getting flooded with data on a
single channel, there are two multicast channels, one for the
temperature sampling when the thermal zone is updated and another one
for the events, so the user can get the events only without the
thermal zone temperature sampling.

Also, a list of commands to discover the thermal setup is added and
can be extended when needed.

Reviewed-by: Amit Kucheria <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Acked-by: Zhang Rui <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine

License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.

By default are files without license information under the default
license of the kernel, which is GPLV2. Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

otherwise syscall usage would not be possible.

Update the files which contain no license information with an SPDX
license identifier. The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception. SPDX license identifiers are a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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thermal: provide an UAPI header file

include/linux/thermal.h contains definitions for the Thermal generic
netlink family, but none of the valuable information relevant to
user-space such as the Genl

thermal: provide an UAPI header file

include/linux/thermal.h contains definitions for the Thermal generic
netlink family, but none of the valuable information relevant to
user-space such as the Genl family name, multicast group, version or
command set and data types is exported to user-space.

Export all the relevant generic netlink information to user-space to
make this genl family usable by user-space, and while at it, export
THERMAL_NAME_LENGTH since it limits name length for thermal_hwmon
devices.

Kbuild and MAINTAINERS are also updated accordingly to reflect this new
file: include/uapi/linux/thermal.h.

Signed-off-by: Florian Fainelli <[email protected]>
Signed-off-by: Zhang Rui <[email protected]>

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