linux-toradex.git/drivers/hwmon/coretemp.c, branch v6.3

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

hwmon: (coretemp) Check for null before removing sysfs attrs

2022-12-01T17:20:24+00:00

If coretemp_add_core() gets an error then pdata->core_data[indx]
is already NULL and has been kfreed. Don't pass that to
sysfs_remove_group() as that will crash in sysfs_remove_group().

[Shortened for readability]
[91854.020159] sysfs: cannot create duplicate filename '/devices/platform/coretemp.0/hwmon/hwmon2/temp20_label'

[91855.126115] BUG: kernel NULL pointer dereference, address: 0000000000000188
[91855.165103] #PF: supervisor read access in kernel mode
[91855.194506] #PF: error_code(0x0000) - not-present page
[91855.224445] PGD 0 P4D 0
[91855.238508] Oops: 0000 [#1] PREEMPT SMP PTI
...
[91855.342716] RIP: 0010:sysfs_remove_group+0xc/0x80
...
[91855.796571] Call Trace:
[91855.810524]  coretemp_cpu_offline+0x12b/0x1dd [coretemp]
[91855.841738]  ? coretemp_cpu_online+0x180/0x180 [coretemp]
[91855.871107]  cpuhp_invoke_callback+0x105/0x4b0
[91855.893432]  cpuhp_thread_fun+0x8e/0x150
...

Fix this by checking for NULL first.

Signed-off-by: Phil Auld 
Cc: linux-hwmon@vger.kernel.org
Cc: Fenghua Yu 
Cc: Jean Delvare 
Cc: Guenter Roeck 
Link: https://lore.kernel.org/r/20221117162313.3164803-1-pauld@redhat.com
Fixes: 199e0de7f5df3 ("hwmon: (coretemp) Merge pkgtemp with coretemp")
Signed-off-by: Guenter Roeck

hwmon/coretemp: Handle large core ID value

2022-10-17T18:58:52+00:00

The coretemp driver supports up to a hard-coded limit of 128 cores.

Today, the driver can not support a core with an ID above that limit.
Yet, the encoding of core ID's is arbitrary (BIOS APIC-ID) and so they
may be sparse and they may be large.

Update the driver to map arbitrary core ID numbers into appropriate
array indexes so that 128 cores can be supported, no matter the encoding
of core ID's.

Signed-off-by: Zhang Rui 
Signed-off-by: Dave Hansen 
Acked-by: Len Brown 
Acked-by: Guenter Roeck 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20221014090147.1836-3-rui.zhang@intel.com

hwmon: cleanup non-bool "valid" data fields

2021-10-12T14:22:41+00:00

We have bool so use it consistently in all the drivers.

The following Coccinelle script was used:

@@
identifier T;
type t = { char, int };
@@
struct T {
...
-	t valid;
+	bool valid;
...
}

@@
identifier v;
@@
(
- v->valid = 0
+ v->valid = false
|
- v->valid = 1
+ v->valid = true
)

followed by sed to fixup the comments:
sed '/bool valid;/{s/!=0/true/;s/zero/false/}'

Few whitespace changes were fixed manually. All modified drivers were
compile-tested.

Signed-off-by: Paul Fertser 
Link: https://lore.kernel.org/r/20210924195202.27917-1-fercerpav@gmail.com
[groeck: Fixed up 'u8 valid' to 'boool valid' in atxp1.c]
Signed-off-by: Guenter Roeck