159 Commits
Author SHA1 Message Date
Kees CookandLinus Torvalds 189f164e57 Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses
Conversion performed via this Coccinelle script:

  // SPDX-License-Identifier: GPL-2.0-only
  // Options: --include-headers-for-types --all-includes --include-headers --keep-comments
  virtual patch

  @gfp depends on patch && !(file in "tools") && !(file in "samples")@
  identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex,
 		    kzalloc_obj,kzalloc_objs,kzalloc_flex,
		    kvmalloc_obj,kvmalloc_objs,kvmalloc_flex,
		    kvzalloc_obj,kvzalloc_objs,kvzalloc_flex};
  @@

  	ALLOC(...
  -		, GFP_KERNEL
  	)

  $ make coccicheck MODE=patch COCCI=gfp.cocci

Build and boot tested x86_64 with Fedora 42's GCC and Clang:

Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01
Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01

Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-22 08:26:33 -08:00
Linus Torvalds 32a92f8c89 Convert more 'alloc_obj' cases to default GFP_KERNEL arguments
This converts some of the visually simpler cases that have been split
over multiple lines.  I only did the ones that are easy to verify the
resulting diff by having just that final GFP_KERNEL argument on the next
line.

Somebody should probably do a proper coccinelle script for this, but for
me the trivial script actually resulted in an assertion failure in the
middle of the script.  I probably had made it a bit _too_ trivial.

So after fighting that far a while I decided to just do some of the
syntactically simpler cases with variations of the previous 'sed'
scripts.

The more syntactically complex multi-line cases would mostly really want
whitespace cleanup anyway.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 20:03:00 -08:00
Linus Torvalds bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook 69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Laveesh BansalandGuenter Roeck bcd5120ad4 hwmon: (coretemp) Add TjMax for Silvermont through Tremont Atoms
Add fallback TjMax values for Intel Atom processors based on Silvermont,
Airmont, Goldmont, and Tremont microarchitectures. These processors
support MSR_IA32_TEMPERATURE_TARGET for reading TjMax directly, so these
table entries serve as fallback values only when the MSR read fails
(e.g., in some virtualization scenarios).

Added processors and TjMax values:

- INTEL_ATOM_SILVERMONT (0x37, Bay Trail):
  - Stepping 9 (E38xx embedded): 110C
  - Other steppings (Z37xx tablet): 90C
  Stepping identified from Intel E3800 Specification Update.

- INTEL_ATOM_SILVERMONT_MID (0x4a, Merrifield): 90C

- INTEL_ATOM_SILVERMONT_MID2 (0x5a, Moorefield): 90C

- INTEL_ATOM_AIRMONT (0x4c, Cherry Trail): 90C

- INTEL_ATOM_GOLDMONT (0x5c, Apollo Lake): 105C

- INTEL_ATOM_GOLDMONT_PLUS (0x7a, Gemini Lake): 105C

- INTEL_ATOM_TREMONT (0x96, Elkhart Lake): 105C

- INTEL_ATOM_TREMONT_L (0x9c, Jasper Lake): 105C

Not included (MSR reads work reliably, server/specialized chips):
- INTEL_ATOM_SILVERMONT_D (Avoton): Server, Tcase 97C
- INTEL_ATOM_GOLDMONT_D (Denverton): Server, Tcase 82C
- INTEL_ATOM_AIRMONT_NP (Lightning Mountain): Network processor
- INTEL_ATOM_TREMONT_D (Jacobsville): Server
- INTEL_ATOM_GRACEMONT (Alder Lake-N): Very new, MSR works

Reference: Intel datasheets and ARK processor specifications
- Z3600/Z3700 datasheet: https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/atom-z36xxx-z37xxx-datasheet-vol-1.pdf
- E3845 ARK: https://www.intel.com/content/www/us/en/products/sku/78475/intel-atom-processor-e3845-2m-cache-1-91-ghz/specifications.html
- E3800 Spec Update: https://community.intel.com/cipcp26785/attachments/cipcp26785/embedded-atom-processors/4708/1/600834-329901-intel-atom-processor-e3800-product-family-su-rev015.pdf

Signed-off-by: Laveesh Bansal <laveeshb@laveeshbansal.com>
Link: https://lore.kernel.org/r/20260106155426.547872-3-laveeshb@laveeshbansal.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2026-01-31 07:38:32 -08:00
Dave HansenandGuenter Roeck 468a20df2b hwmon: (coretemp) Replace x86_model checks with VFM ones
Intel CPUs have been using Family 6 for a while. The Family-model checks
in the coretemp driver implicitly assume Family 6. With the upcoming
Family 18 and 19 models, some of these checks fall apart.

While reading the temperature target MSR, cpu_has_tjmax() performs model
checks only to determine if a device warning should be printed. Instead
of expanding the checks, get rid of the function and print the warning
once unconditionally if the MSR read fails. The checks aren't worth
preventing a single line warning to dmesg.

Update the rest of the x86_model checks with VFM ones to make them more
robust. This automatically covers the upcoming Family 18 and 19 as well
as any future extended families.

Add a code comment to reflect that none of the CPUs in Family 5 or
Family 15 set X86_FEATURE_DTHERM. The VFM checks do not impact these
CPUs since the driver does not load on them.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20250828201729.1145420-1-sohil.mehta@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2025-09-07 16:33:47 -07:00
Ricardo NeriandGuenter Roeck f0c344c000 hwmon: (coretemp) Extend the bitmask to read temperature to 0xff
The Intel Software Development manual defines the temperature digital
readout as the bits [22:16] of the IA32_[PACKAGE]_THERM_STATUS registers.
Bit 23 is specified as reserved.

In recent processors, however, the temperature digital readout uses bits
[23:16]. In those processors, using the bitmask 0x7f would lead to
incorrect readings if the temperature deviates from TjMax by more than
127 degrees Celsius.

Although not guaranteed, bit 23 is likely to be 0 in processors from a few
generations ago. The temperature reading would still be correct in those
processors when using a 0xff bitmask.

Model-specific provisions can be made for older processors in which bit 23
is not 0 should the need arise.

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Link: https://lore.kernel.org/r/20240425171311.19519-4-ricardo.neri-calderon@linux.intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-04-28 10:08:43 -07:00
Linus Torvalds 15223fdbdf Merge tag 'hwmon-for-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon updates from Guenter Roeck:
 "New drivers:
   - Amphenol ChipCap 2
   - ASPEED g6 PWM/Fan tach
   - Astera Labs PT5161L retimer
   - ASUS ROG RYUJIN II 360 AIO cooler
   - LTC4282
   - Microsoft Surface devices
   - MPS MPQ8785 Synchronous Step-Down Converter
   - NZXT Kraken X and Z series AIO CPU coolers

  Additional chip support in existing drivers:
   - Ayaneo Air Plus 7320u (oxp-sensors)
   - INA260 (ina2xx)
   - XPS 9315 (dell-smm)
   - MSI customer ID (nct6683)

  Devicetree bindings updates:
   - Common schema for hardware monitoring devices
   - Common schema for fans
   - Update chip descriptions to use common schema
   - Document regulator properties in several drivers
   - Explicit bindings for infineon buck converters

  Other improvements:
   - Replaced rbtree with maple tree register cache in several drivers
   - Added support for humidity min/max alarm and volatage fault
     attributes to hwmon core
   - Dropped non-functional I2C_CLASS_HWMON support for drivers w/o
     detect()
   - Dropped obsolete and redundant entried from MAINTAINERS
   - Cleaned up axi-fan-control and coretemp drivers
   - Minor fixes and improvements in several other drivers"

* tag 'hwmon-for-v6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: (70 commits)
  hwmon: (dell-smm) Add XPS 9315 to fan control whitelist
  hwmon: (aspeed-g6-pwm-tacho): Support for ASPEED g6 PWM/Fan tach
  dt-bindings: hwmon: Support Aspeed g6 PWM TACH Control
  dt-bindings: hwmon: fan: Add fan binding to schema
  dt-bindings: hwmon: tda38640: Add interrupt & regulator properties
  hwmon: (amc6821) add of_match table
  dt-bindings: hwmon: lm75: use common hwmon schema
  hwmon: (sis5595) drop unused DIV_TO_REG function
  dt-bindings: hwmon: reference common hwmon schema
  dt-bindings: hwmon: lltc,ltc4286: use common hwmon schema
  dt-bindings: hwmon: adi,adm1275: use common hwmon schema
  dt-bindings: hwmon: ti,ina2xx: use common hwmon schema
  dt-bindings: hwmon: add common properties
  hwmon: (pmbus/ir38064) Use PMBUS_REGULATOR_ONE to declare regulator
  hwmon: (pmbus/lm25066) Use PMBUS_REGULATOR_ONE to declare regulator
  hwmon: (pmbus/tda38640) Use PMBUS_REGULATOR_ONE to declare regulator
  regulator: dt-bindings: promote infineon buck converters to their own binding
  dt-bindings: hwmon/pmbus: ti,lm25066: document regulators
  dt-bindings: hwmon: nuvoton,nct6775: Add compatible value for NCT6799
  MAINTAINERS: Drop redundant hwmon entries
  ...
2024-03-13 11:26:58 -07:00
Zhang RuiandGuenter Roeck 1a793caf6f hwmon: (coretemp) Use dynamic allocated memory for core temp_data
The total memory needed for saving per core temperature data depends on
the number of cores in a package. Using static allocated memory wastes
memories on systems with low per package core count.

Improve the code to use dynamic allocated memory so that it can be
improved further when per package core count information becomes
available.

No functional change intended.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-12-rui.zhang@intel.com
[groeck: Fixed continuation line alignment]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Zhang RuiandGuenter Roeck 18b24a5f9c hwmon: (coretemp) Remove redundant temp_data->is_pkg_data
temp_data->index saves the index in pdata->core_data[]. It is not used
by package temp_data.

Use temp_data->index as the indicator of package temp_data and remove
redundant temp_data->is_pkg_data.

No functional change.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-11-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Zhang RuiandGuenter Roeck 326241f71f hwmon: (coretemp) Split package temp_data and core temp_data
Saving package temp_data and core temp_data in one array with different
offsets is fragile.

Split them and clean up crabbed maths and macros. This also fixes a
problem that pdata->core_data[0] was never used.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-10-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Zhang RuiandGuenter Roeck b0b01414a2 hwmon: (coretemp) Abstract core_temp helpers
coretemp driver has an obscure and fragile logic for handling package
and core temperature data.

Place the logic in newly introduced helpers for further optimizations.

No functional change.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-9-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Zhang RuiandGuenter Roeck 87eb801925 hwmon: (coretemp) Remove redundant pdata->cpu_map[]
pdata->cpu_map[] saves the mapping between cpu core id and the index in
pdata->core_data[]. This is used to find the temp_data structure using
cpu_core_id, by traversing the pdata->cpu_map[] array. But the same goal
can be achieved by traversing the pdata->core_temp[] array directly.

Remove redundant pdata->cpu_map[].

No functional change.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-8-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Zhang RuiandGuenter Roeck 18d8f55833 hwmon: (coretemp) Replace sensor_device_attribute with device_attribute
Replace sensor_device_attribute with device_attribute because
sensor_device_attribute->index is no longer used.

No functional change.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-7-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Zhang RuiandGuenter Roeck 25f8e01baa hwmon: (coretemp) Remove unnecessary dependency of array index
When sensor_device_attribute pointer is available, use container_of() to
get the temp_data address.

This removes the unnecessary dependency of cached index in
pdata->core_data[].

No functional change.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-6-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Zhang RuiandGuenter Roeck c8c2074020 hwmon: (coretemp) Introduce enum for attr index
Introduce enum coretemp_attr_index to better describe the index of each
sensor attribute.

No functional change.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-5-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:37 -08:00
Thomas Gleixner bd745d1c41 x86/cpu/topology: Rename topology_max_die_per_package()
The plural of die is dies.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210253.065874205@linutronix.de
2024-02-15 22:07:45 +01:00
Zhang RuiandGuenter Roeck 34cf8c657c hwmon: (coretemp) Enlarge per package core count limit
Currently, coretemp driver supports only 128 cores per package.
This loses some core temperature information on systems that have more
than 128 cores per package.
 [   58.685033] coretemp coretemp.0: Adding Core 128 failed
 [   58.692009] coretemp coretemp.0: Adding Core 129 failed
 ...

Enlarge the limitation to 512 because there are platforms with more than
256 cores per package.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-4-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-04 06:43:45 -08:00
Zhang RuiandGuenter Roeck fdaf0c8629 hwmon: (coretemp) Fix bogus core_id to attr name mapping
Before commit 7108b80a54 ("hwmon/coretemp: Handle large core ID
value"), there is a fixed mapping between
1. cpu_core_id
2. the index in pdata->core_data[] array
3. the sysfs attr name, aka "tempX_"
The later two always equal cpu_core_id + 2.

After the commit, pdata->core_data[] index is got from ida so that it
can handle sparse core ids and support more cores within a package.

However, the commit erroneously maps the sysfs attr name to
pdata->core_data[] index instead of cpu_core_id + 2.

As a result, the code is not aligned with the comments, and brings user
visible changes in hwmon sysfs on systems with sparse core id.

For example, before commit 7108b80a54 ("hwmon/coretemp: Handle large
core ID value"),
/sys/class/hwmon/hwmon2/temp2_label:Core 0
/sys/class/hwmon/hwmon2/temp3_label:Core 1
/sys/class/hwmon/hwmon2/temp4_label:Core 2
/sys/class/hwmon/hwmon2/temp5_label:Core 3
/sys/class/hwmon/hwmon2/temp6_label:Core 4
/sys/class/hwmon/hwmon3/temp10_label:Core 8
/sys/class/hwmon/hwmon3/temp11_label:Core 9
after commit,
/sys/class/hwmon/hwmon2/temp2_label:Core 0
/sys/class/hwmon/hwmon2/temp3_label:Core 1
/sys/class/hwmon/hwmon2/temp4_label:Core 2
/sys/class/hwmon/hwmon2/temp5_label:Core 3
/sys/class/hwmon/hwmon2/temp6_label:Core 4
/sys/class/hwmon/hwmon2/temp7_label:Core 8
/sys/class/hwmon/hwmon2/temp8_label:Core 9

Restore the previous behavior and rework the code, comments and variable
names to avoid future confusions.

Fixes: 7108b80a54 ("hwmon/coretemp: Handle large core ID value")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20240202092144.71180-3-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-04 06:43:45 -08:00
Zhang RuiandGuenter Roeck 4e440abc89 hwmon: (coretemp) Fix out-of-bounds memory access
Fix a bug that pdata->cpu_map[] is set before out-of-bounds check.
The problem might be triggered on systems with more than 128 cores per
package.

Fixes: 7108b80a54 ("hwmon/coretemp: Handle large core ID value")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20240202092144.71180-2-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-04 06:43:44 -08:00
Zhang RuiandGuenter Roeck bbfff736d3 hwmon: (coretemp) Fix potentially truncated sysfs attribute name
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 <rui.zhang@intel.com>
Fixes: 7108b80a54 ("hwmon/coretemp: Handle large core ID value")
Reported-by: kernel test robot <lkp@intel.com>
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 <linux@roeck-us.net>
2023-10-25 11:57:54 -07:00
Zhang RuiandGuenter Roeck a2930f6dc9 hwmon: (coretemp) Delete an obsolete comment
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 <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20230330103346.6044-2-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-04-19 07:08:39 -07:00
Zhang RuiandGuenter Roeck 6c2b659913 hwmon: (coretemp) Delete tjmax debug message
After commit c0c67f8761 ("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 <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20230330103346.6044-1-rui.zhang@intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-04-19 07:08:39 -07:00
Robin MurphyandGuenter Roeck 6d03bbff45 hwmon: (coretemp) Simplify platform device handling
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 <robin.murphy@arm.com>
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Link: https://lore.kernel.org/r/20230103114620.15319-1-janusz.krzysztofik@linux.intel.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-02-03 07:30:09 -08:00
Marcelo TosattiandGuenter Roeck 0f8b916bc5 hwmon: (coretemp) avoid RDMSR interrupts to isolated CPUs
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 <mtosatti@redhat.com>
Link: https://lore.kernel.org/r/Y5zT6B1mY9/pnwJV@tpad
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-02-03 07:30:09 -08:00