linux-toradex.git/drivers/hwmon/coretemp.c, branch v6.7

hwmon: (coretemp) Fix potentially truncated sysfs attribute name

2023-10-25T18:57:54+00:00

When build with W=1 and "-Werror=format-truncation", below error is
observed in coretemp driver,

   drivers/hwmon/coretemp.c: In function 'create_core_data':
>> drivers/hwmon/coretemp.c:393:34: error: '%s' directive output may be truncated writing likely 5 or more bytes into a region of size between 3 and 13 [-Werror=format-truncation=]
     393 |                          "temp%d_%s", attr_no, suffixes[i]);
         |                                  ^~
   drivers/hwmon/coretemp.c:393:26: note: assuming directive output of 5 bytes
     393 |                          "temp%d_%s", attr_no, suffixes[i]);
         |                          ^~~~~~~~~~~
   drivers/hwmon/coretemp.c:392:17: note: 'snprintf' output 7 or more bytes (assuming 22) into a destination of size 19
     392 |                 snprintf(tdata->attr_name[i], CORETEMP_NAME_LENGTH,
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     393 |                          "temp%d_%s", attr_no, suffixes[i]);
         |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors

Given that
1. '%d' could take 10 charactors,
2. '%s' could take 10 charactors ("crit_alarm"),
3. "temp", "_" and the NULL terminator take 6 charactors,
fix the problem by increasing CORETEMP_NAME_LENGTH to 28.

Signed-off-by: Zhang Rui 
Fixes: 7108b80a542b ("hwmon/coretemp: Handle large core ID value")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202310200443.iD3tUbbK-lkp@intel.com/
Link: https://lore.kernel.org/r/20231025122316.836400-1-rui.zhang@intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) Delete an obsolete comment

2023-04-19T14:08:39+00:00

The refinement of tjmax value retrieved from MSR_IA32_TEMPERATURE_TARGET
has been changed for several times.

Now, the raw value from MSR is used without refinement. Thus remove the
obsolete comment.

Signed-off-by: Zhang Rui 
Link: https://lore.kernel.org/r/20230330103346.6044-2-rui.zhang@intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) Delete tjmax debug message

2023-04-19T14:08:39+00:00

After commit c0c67f8761ce ("hwmon: (coretemp) Add support for dynamic
tjmax"), tjmax value is retrieved from MSR every time the temperature is
read.
This means that, with debug message enabled, the tjmax debug message is
printed out for every single temperature read for any CPU. This spams
the syslog.

Ideally, as tjmax is package scope unique, the debug message should show
once when tjmax is changed for one package. But this requires inventing
some new per-package data in the coretemp driver, and this is overkill.

To keep the code simple, delete the tjmax debug message.

Signed-off-by: Zhang Rui 
Link: https://lore.kernel.org/r/20230330103346.6044-1-rui.zhang@intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) Simplify platform device handling

2023-02-03T15:30:09+00:00

Coretemp's platform driver is unconventional. All the real work is done
globally by the initcall and CPU hotplug notifiers, while the "driver"
effectively just wraps an allocation and the registration of the hwmon
interface in a long-winded round-trip through the driver core.  The whole
logic of dynamically creating and destroying platform devices to bring
the interfaces up and down is error prone, since it assumes
platform_device_add() will synchronously bind the driver and set drvdata
before it returns, thus results in a NULL dereference if drivers_autoprobe
is turned off for the platform bus. Furthermore, the unusual approach of
doing that from within a CPU hotplug notifier, already commented in the
code that it deadlocks suspend, also causes lockdep issues for other
drivers or subsystems which may want to legitimately register a CPU
hotplug notifier from a platform bus notifier.

All of these issues can be solved by ripping this unusual behaviour out
completely, simply tying the platform devices to the lifetime of the
module itself, and directly managing the hwmon interfaces from the
hotplug notifiers. There is a slight user-visible change in that
/sys/bus/platform/drivers/coretemp will no longer appear, and
/sys/devices/platform/coretemp.n will remain present if package n is
hotplugged off, but hwmon users should really only be looking for the
presence of the hwmon interfaces, whose behaviour remains unchanged.

Link: https://lore.kernel.org/lkml/20220922101036.87457-1-janusz.krzysztofik@linux.intel.com/
Link: https://gitlab.freedesktop.org/drm/intel/issues/6641
Signed-off-by: Robin Murphy 
Signed-off-by: Janusz Krzysztofik 
Link: https://lore.kernel.org/r/20230103114620.15319-1-janusz.krzysztofik@linux.intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) avoid RDMSR interrupts to isolated CPUs

2023-02-03T15:30:09+00:00

The coretemp driver uses rdmsr_on_cpu calls to read
MSR_IA32_PACKAGE_THERM_STATUS/MSR_IA32_THERM_STATUS registers,
which contain information about current core temperature.

For certain low latency applications, the RDMSR interruption exceeds
the applications requirements.

So do not create core files in sysfs, for CPUs which have
isolation and nohz_full enabled.

Temperature information from the housekeeping cores should be
sufficient to infer die temperature.

Signed-off-by: Marcelo Tosatti 
Link: https://lore.kernel.org/r/Y5zT6B1mY9/pnwJV@tpad
Signed-off-by: Guenter Roeck

hwmon: (coretemp) Add support for dynamic ttarget

2022-12-05T00:45:03+00:00

Tjmax value retrieved from MSR_IA32_TEMPERATURE_TARGET can be changed at
runtime when the Intel SST-PP (Intel Speed Select Technology -
Performance Profile) level is changed. As a result, the ttarget value
also becomes dyamic.

Improve the code to always get updated ttarget value.

Signed-off-by: Zhang Rui 
Link: https://lore.kernel.org/r/20221113153145.32696-4-rui.zhang@intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) Add support for dynamic tjmax

2022-12-05T00:45:03+00:00

Tjmax value retrieved from MSR_IA32_TEMPERATURE_TARGET can be changed at
runtime when the Intel SST-PP (Intel Speed Select Technology -
Performance Profile) level is changed.

Improve the code to always use updated tjmax when it can be retrieved
from MSR_IA32_TEMPERATURE_TARGET.

When tjmax can not be retrieved from MSR_IA32_TEMPERATURE_TARGET, still
follow the previous logic and always use a static tjmax value.

Signed-off-by: Zhang Rui 
Link: https://lore.kernel.org/r/20221113153145.32696-3-rui.zhang@intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) rearrange tjmax handing code

2022-12-05T00:45:03+00:00

Rearrange the tjmax handling code so that it can be used directly in
the sysfs attribute callbacks without forward declarations.

No functional change in this patch.

Signed-off-by: Zhang Rui 
Link: https://lore.kernel.org/r/20221113153145.32696-2-rui.zhang@intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) Remove obsolete temp_data->valid

2022-12-05T00:45:02+00:00

Checking for the valid bit of IA32_THERM_STATUS is removed in commit
bf6ea084ebb5 ("hwmon: (coretemp) Do not return -EAGAIN for low
temperatures"), and temp_data->valid is set and never cleared when the
temperature has been read once.

Remove the obsolete temp_data->valid field.

Signed-off-by: Zhang Rui 
Link: https://lore.kernel.org/r/20221108075051.5139-2-rui.zhang@intel.com
Signed-off-by: Guenter Roeck

hwmon: (coretemp) fix pci device refcount leak in nv1a_ram_new()

2022-12-01T17:20:55+00:00

As comment of pci_get_domain_bus_and_slot() says, it returns
a pci device with refcount increment, when finish using it,
the caller must decrement the reference count by calling
pci_dev_put(). So call it after using to avoid refcount leak.

Fixes: 14513ee696a0 ("hwmon: (coretemp) Use PCI host bridge ID to identify CPU if necessary")
Signed-off-by: Yang Yingliang 
Link: https://lore.kernel.org/r/20221118093303.214163-1-yangyingliang@huawei.com
Signed-off-by: Guenter Roeck