linux-toradex.git/drivers/cpuidle/cpuidle.c, branch v7.0-rc2 Linux kernel for Apalis and Colibri modules cpuidle: Skip governor when only one idle state is available 2026-02-17T14:49:02+00:00 Aboorva Devarajan aboorvad@linux.ibm.com 2026-02-16T18:50:02+00:00 e5c9ffc6ae1bcdb1062527d611043681ac301aca On certain platforms (PowerNV systems without a power-mgt DT node), cpuidle may register only a single idle state. In cases where that single state is a polling state (state 0), the ladder governor may incorrectly treat state 1 as the first usable state and pass an out-of-bounds index. This can lead to a NULL enter callback being invoked, ultimately resulting in a system crash. [ 13.342636] cpuidle-powernv : Only Snooze is available [ 13.351854] Faulting instruction address: 0x00000000 [ 13.376489] NIP [0000000000000000] 0x0 [ 13.378351] LR [c000000001e01974] cpuidle_enter_state+0x2c4/0x668 Fix this by adding a bail-out in cpuidle_select() that returns state 0 directly when state_count <= 1, bypassing the governor and keeping the tick running. Fixes: dc2251bf98c6 ("cpuidle: Eliminate the CPUIDLE_DRIVER_STATE_START symbol") Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Reviewed-by: Christian Loehle <christian.loehle@arm.com> Link: https://patch.msgid.link/20260216185005.1131593-2-aboorvad@linux.ibm.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
On certain platforms (PowerNV systems without a power-mgt DT node),
cpuidle may register only a single idle state. In cases where that
single state is a polling state (state 0), the ladder governor may
incorrectly treat state 1 as the first usable state and pass an
out-of-bounds index. This can lead to a NULL enter callback being
invoked, ultimately resulting in a system crash.

[   13.342636] cpuidle-powernv : Only Snooze is available
[   13.351854] Faulting instruction address: 0x00000000
[   13.376489] NIP [0000000000000000] 0x0
[   13.378351] LR  [c000000001e01974] cpuidle_enter_state+0x2c4/0x668

Fix this by adding a bail-out in cpuidle_select() that returns state 0
directly when state_count <= 1, bypassing the governor and keeping the
tick running.

Fixes: dc2251bf98c6 ("cpuidle: Eliminate the CPUIDLE_DRIVER_STATE_START symbol")
Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/20260216185005.1131593-2-aboorvad@linux.ibm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
sched: idle: Respect the CPU system wakeup QoS limit for s2idle 2025-11-25T18:01:29+00:00 Ulf Hansson ulf.hansson@linaro.org 2025-11-25T11:26:45+00:00 99b42445f4a4aaff75eca24dfc9e6e376292dd48 A CPU system wakeup QoS limit may have been requested by user space. To avoid breaking this constraint when entering a low power state during s2idle, let's start to take into account the QoS limit. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dhruva Gole <d-gole@ti.com> Reviewed-by: Kevin Hilman (TI) <khilman@baylibre.com> Tested-by: Kevin Hilman (TI) <khilman@baylibre.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Link: https://patch.msgid.link/20251125112650.329269-5-ulf.hansson@linaro.org Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
A CPU system wakeup QoS limit may have been requested by user space. To
avoid breaking this constraint when entering a low power state during
s2idle, let's start to take into account the QoS limit.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Kevin Hilman (TI) <khilman@baylibre.com>
Tested-by: Kevin Hilman (TI) <khilman@baylibre.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/20251125112650.329269-5-ulf.hansson@linaro.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpuidle: Fail cpuidle device registration if there is one already 2025-09-20T11:08:54+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2025-09-19T11:22:20+00:00 7b1b7961170e4fcad488755e5ffaaaf9bd527e8f Refuse to register a cpuidle device if the given CPU has a cpuidle device already and print a message regarding it. Without this, an attempt to register a new cpuidle device without unregistering the existing one leads to the removal of the existing cpuidle device without removing its sysfs interface. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Refuse to register a cpuidle device if the given CPU has a cpuidle
device already and print a message regarding it.

Without this, an attempt to register a new cpuidle device without
unregistering the existing one leads to the removal of the existing
cpuidle device without removing its sysfs interface.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpuidle: Do not return from cpuidle_play_dead() on callback failures 2024-11-19T20:46:51+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2024-11-15T20:58:31+00:00 f65ee094eda6e5897172a1276ffee88cf5489928 If the :enter_dead() idle state callback fails for a certain state, there may be still a shallower state for which it will work. Because the only caller of cpuidle_play_dead(), native_play_dead(), falls back to hlt_play_dead() if it returns an error, it should better try all of the idle states for which :enter_dead() is present before failing, so change it accordingly. Also notice that the :enter_dead() state callback is not expected to return on success (the CPU should be "dead" then), so make cpuidle_play_dead() ignore its return value. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Tested-by: Mario Limonciello <mario.limonciello@amd.com> # 6.12-rc7 Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Link: https://patch.msgid.link/3318440.aeNJFYEL58@rjwysocki.net 
If the :enter_dead() idle state callback fails for a certain state,
there may be still a shallower state for which it will work.

Because the only caller of cpuidle_play_dead(), native_play_dead(),
falls back to hlt_play_dead() if it returns an error, it should
better try all of the idle states for which :enter_dead() is present
before failing, so change it accordingly.

Also notice that the :enter_dead() state callback is not expected
to return on success (the CPU should be "dead" then), so make
cpuidle_play_dead() ignore its return value.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Mario Limonciello <mario.limonciello@amd.com> # 6.12-rc7
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://patch.msgid.link/3318440.aeNJFYEL58@rjwysocki.net
cpuidle: Correct some typos in comments 2024-10-18T16:44:32+00:00 Shen Lichuan shenlichuan@vivo.com 2024-09-27T08:10:18+00:00 ee702fdaf1563078758065aca7beb5e5d89367e5 Fixed some confusing typos that were currently identified with codespell, the details are as follows: -in the code comments: drivers/cpuidle/cpuidle-arm.c:142: registeration ==> registration drivers/cpuidle/cpuidle-qcom-spm.c:51: accidently ==> accidentally drivers/cpuidle/cpuidle.c:409: dependant ==> dependent drivers/cpuidle/driver.c:264: occuring ==> occurring drivers/cpuidle/driver.c:299: occuring ==> occurring Signed-off-by: Shen Lichuan <shenlichuan@vivo.com> Link: https://patch.msgid.link/20240927081018.8608-1-shenlichuan@vivo.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Fixed some confusing typos that were currently identified with codespell,
the details are as follows:

 -in the code comments:
  drivers/cpuidle/cpuidle-arm.c:142: registeration ==> registration
  drivers/cpuidle/cpuidle-qcom-spm.c:51: accidently ==> accidentally
  drivers/cpuidle/cpuidle.c:409: dependant ==> dependent
  drivers/cpuidle/driver.c:264: occuring ==> occurring
  drivers/cpuidle/driver.c:299: occuring ==> occurring

Signed-off-by: Shen Lichuan <shenlichuan@vivo.com>
Link: https://patch.msgid.link/20240927081018.8608-1-shenlichuan@vivo.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpuidle: remove dead code from cpuidle_enter_state() 2024-08-22T19:03:52+00:00 Dhruva Gole d-gole@ti.com 2024-08-21T11:42:50+00:00 6baacf9391c03f91a7644b3f94634b7d4b2c5e34 Checking for index < 0 is useless because the find_deepest_state() function never really returns a negative value. Since this hasn't been reported in over 9 years it's dead code, so remove it. Signed-off-by: Dhruva Gole <d-gole@ti.com> Link: https://patch.msgid.link/20240821114250.1416421-1-d-gole@ti.com [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Checking for index < 0 is useless because the find_deepest_state()
function never really returns a negative value.

Since this hasn't been reported in over 9 years it's dead code, so
remove it.

Signed-off-by: Dhruva Gole <d-gole@ti.com>
Link: https://patch.msgid.link/20240821114250.1416421-1-d-gole@ti.com
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
x86/mm: delete unused cpu argument to leave_mm() 2024-02-22T18:24:41+00:00 Yosry Ahmed yosryahmed@google.com 2024-01-26T08:06:43+00:00 7dbbc8f57d4ba3c369b692db9fd2c9653abf0bb5 The argument is unused since commit 3d28ebceaffa ("x86/mm: Rework lazy TLB to track the actual loaded mm"), delete it. Link: https://lkml.kernel.org/r/20240126080644.1714297-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
The argument is unused since commit 3d28ebceaffa ("x86/mm: Rework lazy
TLB to track the actual loaded mm"), delete it.

Link: https://lkml.kernel.org/r/20240126080644.1714297-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cpuidle: Use local_clock_noinstr() 2023-06-05T19:11:09+00:00 Peter Zijlstra peterz@infradead.org 2023-05-19T10:21:11+00:00 e6a15fa9ea8372ad4db973191233f743ae1081d5 With the introduction of local_clock_noinstr(), local_clock() itself is no longer marked noinstr, use the correct function. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rafael J. Wysocki <rafael@kernel.org> Tested-by: Michael Kelley <mikelley@microsoft.com> # Hyper-V Link: https://lore.kernel.org/r/20230519102716.045980863@infradead.org 
With the introduction of local_clock_noinstr(), local_clock() itself
is no longer marked noinstr, use the correct function.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>  # Hyper-V
Link: https://lore.kernel.org/r/20230519102716.045980863@infradead.org
cpuidle: move to use bus_get_dev_root() 2023-03-22T19:25:23+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2023-03-22T09:05:57+00:00 bf6479dbe743ca343fa122aaffbe9dcb1de80a51 Direct access to the struct bus_type dev_root pointer is going away soon so replace that with a call to bus_get_dev_root() instead, which is what it is there for. This allows us to clean up the cpuidle_add_interface() call a bit as it was only called in one place, with the same argument so just put that into the function itself. Note that cpuidle_remove_interface() should also probably be removed in the future as there are no callers of it for some reason. Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-pm@vger.kernel.org Acked-by: Rafael J. Wysocki <rafael@kernel.org> Link: https://lore.kernel.org/r/20230322090557.2943479-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Direct access to the struct bus_type dev_root pointer is going away soon
so replace that with a call to bus_get_dev_root() instead, which is what
it is there for.

This allows us to clean up the cpuidle_add_interface() call a bit as it
was only called in one place, with the same argument so just put that
into the function itself.  Note that cpuidle_remove_interface() should
also probably be removed in the future as there are no callers of it for
some reason.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-pm@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230322090557.2943479-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cpuidle: Fix poll_idle() noinstr annotation 2023-01-31T14:01:47+00:00 Peter Zijlstra peterz@infradead.org 2023-01-26T15:08:38+00:00 4d627628d7584f3d3add1d53342d0f01aa878e04 The instrumentation_begin()/end() annotations in poll_idle() were complete nonsense. Specifically they caused tracing to happen in the middle of noinstr code, resulting in RCU splats. Now that local_clock() is noinstr, mark up the rest and let it rip. Fixes: 00717eb8c955 ("cpuidle: Annotate poll_idle()") Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/oe-lkp/202301192148.58ece903-oliver.sang@intel.com Link: https://lore.kernel.org/r/20230126151323.819534689@infradead.org 
The instrumentation_begin()/end() annotations in poll_idle() were
complete nonsense. Specifically they caused tracing to happen in the
middle of noinstr code, resulting in RCU splats.

Now that local_clock() is noinstr, mark up the rest and let it rip.

Fixes: 00717eb8c955 ("cpuidle: Annotate poll_idle()")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/oe-lkp/202301192148.58ece903-oliver.sang@intel.com
Link: https://lore.kernel.org/r/20230126151323.819534689@infradead.org