kernel/linux.git/drivers/acpi/platform_profile.c, branch v6.12.80

ACPI: platform-profile: Fix CFI violation when accessing sysfs files

2025-04-20T08:16:00+00:00

commit dd4f730b557ce701a2cd4f604bf1e57667bd8b6e upstream. 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 Fixes: a2ff95e018f1 ("ACPI: platform: Add platform profile support") Reported-by: John Rowley Closes: https://github.com/ClangBuiltLinux/linux/issues/2047 Tested-by: John Rowley Reviewed-by: Sami Tolvanen Signed-off-by: Nathan Chancellor Acked-by: Greg Kroah-Hartman Reviewed-by: Mark Pearson Tested-by: Mark Pearson 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 [nathan: Fix conflicts in older stable branches] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman

ACPI: add missing MODULE_DESCRIPTION() macros

2024-06-13T19:06:30+00:00

make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/acpi/acpi_tad.o WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/acpi/platform_profile.o Add the missing invocations of the MODULE_DESCRIPTION() macro. Signed-off-by: Jeff Johnson Signed-off-by: Rafael J. Wysocki

ACPI: platform-profile: add platform_profile_cycle()

2024-04-15T13:46:56+00:00

Some laptops have a key to switch platform profiles. Add a platform_profile_cycle() function to cycle between the enabled profiles. Signed-off-by: Gergo Koteles Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/5a97deddf72aa5e764d881eb39a7ba35c01a903e.1712597199.git.soyer@irl.hu Reviewed-by: Hans de Goede Signed-off-by: Hans de Goede

ACPI: platform-profile: call sysfs_notify() from platform_profile_store()

2021-08-16T16:32:02+00:00

Drivers like thinkpad_acpi and ideapad_laptop call the platform_profile_notify() helper when the profile is changed by hardware (the embedded-controller/EC) in response to an EC handled hotkey. This allows userspace to monitor for such changes by polling for POLLPRI on the platform_profile sysfs file. But the profile can also be changed underneath a userspace program monitoring it by anonther userspace program storing a new value. Add a sysfs_notify() call to platform_profile_store(), so that userspace programs monitoring for changes also get notified in this case. Also update the documentation to document that POLLPRI polling can be used to watch for changes. Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: platform: Add balanced-performance platform profile

2021-02-24T13:52:41+00:00

Some devices, including most Microsoft Surface devices, have a platform profile somewhere inbetween balanced and performance. More specifically, adding this profile allows the following mapping on Surface devices: Vendor Name Platform Profile ------------------------------------------ Battery Saver low-power Recommended balanced Better Performance balanced-performance Best Performance performance Suggested-by: Hans de Goede Signed-off-by: Maximilian Luz Reviewed-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: platform-profile: Fix possible deadlock in platform_profile_remove()

2021-01-27T17:48:12+00:00

After a rmmod thinkpad_acpi, lockdep pointed out this possible deadlock: Our _show and _store sysfs attr functions get called with the kn->active lock held for the sysfs attr and then take the profile_lock. sysfs_remove_group() also takes the kn->active lock for the sysfs attr, so if we call it with the profile_lock held, then we get an ABBA deadlock. platform_profile_remove() must only be called by drivers which have first *successfully* called platform_profile_register(). Anything else is a driver bug. So the check for cur_profile being set before calling sysfs_remove_group() is not necessary and it can be dropped. It is safe to call sysfs_remove_group() without holding the profile_lock since the attr-group group cannot be re-added until after we clear cur_profile. Change platform_profile_remove() to only hold the profile_lock while clearing the cur_profile, fixing the deadlock. Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: platform-profile: Introduce object pointers to callbacks

2021-01-27T17:45:29+00:00

Add an object pointer to handler callbacks to avoid the need for drivers to have a global variable to get to their driver-data struct. Link: https://lore.kernel.org/linux-acpi/6a29f338-d9e4-150c-81dd-2ffb54f5bc35@redhat.com/ Link: https://lore.kernel.org/r/20210114073429.176462-3-jiaxun.yang@flygoat.com Signed-off-by: Jiaxun Yang Suggested-by: Hans de Goede Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: platform-profile: Drop const qualifier for cur_profile

2021-01-25T16:30:10+00:00

Drop the const qualifier from the static global cur_profile pointer declaration. This is a preparation patch for passing the cur_profile pointer as parameter to the profile_get() and profile_set() callbacks so that drivers dynamically allocating their driver-data struct, with their platform_profile_handler struct embedded, can use this pointer to get to their driver-data. Note this also requires dropping the const from the pprof platform_profile_register() function argument. Dropping this const is not a problem, non of the queued up consumers of platform_profile_register() actually pass in a const pointer. Link: https://lore.kernel.org/linux-acpi/5e7a4d87-52ef-e487-9cc2-8e7094beaa08@redhat.com/ Link: https://lore.kernel.org/r/20210114073429.176462-2-jiaxun.yang@flygoat.com Suggested-by: Hans de Goede Signed-off-by: Jiaxun Yang [ hdegoede@redhat.com: Also remove const from platform_profile_register() ] Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki

ACPI: platform: Add platform profile support

2020-12-30T17:34:53+00:00

This is the initial implementation of the platform-profile feature. It provides the details discussed and outlined in the sysfs-platform_profile document. Many modern systems have the ability to modify the operating profile to control aspects like fan speed, temperature and power levels. This module provides a common sysfs interface that platform modules can register against to control their individual profile options. Signed-off-by: Mark Pearson Reviewed-by: Hans de Goede [ rjw: Use full words in enum values names ] Signed-off-by: Rafael J. Wysocki