The platform profile driver is loaded even on platforms that do not have
ACPI enabled. The initialization of the sysfs entries was recently moved
from platform_profile_register() to the module init call, and those
entries need acpi_kobj to be initialized which is not the case when ACPI
is disabled.

This results in the following warning:

 WARNING: CPU: 5 PID: 1 at fs/sysfs/group.c:131 internal_create_group+0xa22/0xdd8
 Modules linked in:
 CPU: 5 UID: 0 PID: 1 Comm: swapper/0 Tainted: G        W           6.15.0-rc7-dirty #6 PREEMPT
 Tainted: [W]=WARN
 Hardware name: riscv-virtio,qemu (DT)
 epc : internal_create_group+0xa22/0xdd8
  ra : internal_create_group+0xa22/0xdd8

 Call Trace:

 internal_create_group+0xa22/0xdd8
 sysfs_create_group+0x22/0x2e
 platform_profile_init+0x74/0xb2
 do_one_initcall+0x198/0xa9e
 kernel_init_freeable+0x6d8/0x780
 kernel_init+0x28/0x24c
 ret_from_fork+0xe/0x18

Fix this by checking if ACPI is enabled before trying to create sysfs
entries.

Fixes: 77be5cacb2c2 ("ACPI: platform_profile: Create class for ACPI platform profile")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://patch.msgid.link/20250522141410.31315-1-alexghiti@rivosinc.com
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Choices aggregates passed to _aggregate_choices() are already filled
with ones, therefore we can avoid copying a new bitmap on the first
iteration.

This makes setting the PLATFORM_PROFILE_LAST bit on aggregates
unnecessary, so drop it as well.

While at it, add a couple empty lines to improve style.

Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Link: https://patch.msgid.link/20250325-pprof-opt-v2-1-736291e6e66b@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

When two drivers don't support all the same profiles the legacy interface
only exports the common profiles.

This causes problems for cases where one driver uses low-power but another
uses quiet because the result is that neither is exported to sysfs.

To allow two drivers to disagree, add support for "hidden choices".
Hidden choices are platform profiles that a driver supports to be
compatible with the platform profile of another driver.

Fixes: 688834743d67 ("ACPI: platform_profile: Allow multiple handlers")
Reported-by: Antheas Kapenekakis <lkml@antheas.dev>
Closes: https://lore.kernel.org/platform-driver-x86/e64b771e-3255-42ad-9257-5b8fc6c24ac9@gmx.de/T/#mc068042dd29df36c16c8af92664860fc4763974b
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Antheas Kapenekakis <lkml@antheas.dev>
Tested-by: Derek J. Clark <derekjohn.clark@gmail.com>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20250228170155.2623386-2-superm1@kernel.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If class_find_device() finds a device, it's reference count is
incremented.

Call put_device() to drop this reference before returning.

Fixes: 77be5cacb2c2 ("ACPI: platform_profile: Create class for ACPI platform profile")
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://patch.msgid.link/20250212193058.32110-1-kuurtb@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Drivers usually call this method on error/exit paths and do not check
for it's return value, which is always 0 anyway, so make it void.

This is safe to do as currently all drivers use
devm_platform_profile_register().

While at it, improve the style and make the function safer by checking
for IS_ERR_OR_NULL before dereferencing the device pointer.

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://patch.msgid.link/20250212190308.21209-1-kuurtb@gmail.com
[ rjw: Minor changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

When an attribute group is created with sysfs_create_group(), the
->sysfs_ops() callback is set to kobj_sysfs_ops, which sets the ->show()
and ->store() callbacks to kobj_attr_show() and kobj_attr_store()
respectively. These functions use container_of() to get the respective
callback from the passed attribute, meaning that these callbacks need to
be of the same type as the callbacks in 'struct kobj_attribute'.

However, ->show() and ->store() in the platform_profile driver are
defined for struct device_attribute with the help of DEVICE_ATTR_RO()
and DEVICE_ATTR_RW(), which results in a CFI violation when accessing
platform_profile or platform_profile_choices under /sys/firmware/acpi
because the types do not match:

  CFI failure at kobj_attr_show+0x19/0x30 (target: platform_profile_choices_show+0x0/0x140; expected type: 0x7a69590c)

There is no functional issue from the type mismatch because the layout
of 'struct kobj_attribute' and 'struct device_attribute' are the same,
so the container_of() cast does not break anything aside from CFI.

Change the type of platform_profile_choices_show() and
platform_profile_{show,store}() to match the callbacks in
'struct kobj_attribute' and update the attribute variables to
match, which resolves the CFI violation.

Cc: All applicable <stable@vger.kernel.org>
Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support")
Reported-by: John Rowley <lkml@johnrowley.me>
Closes: https://github.com/ClangBuiltLinux/linux/issues/2047
Tested-by: John Rowley <lkml@johnrowley.me>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://patch.msgid.link/20250210-acpi-platform_profile-fix-cfi-violation-v3-1-ed9e9901c33a@kernel.org
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Declare a pr_fmt prefix.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://lore.kernel.org/r/20250116002721.75592-20-kuurtb@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Add kerneldoc and sysfs class documentation.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://lore.kernel.org/r/20250116002721.75592-19-kuurtb@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>