cpuidle, cpu_pm: Remove RCU fiddling from cpu_pm_{enter,exit}()

All callers should still have RCU enabled.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <m

cpuidle, cpu_pm: Remove RCU fiddling from cpu_pm_{enter,exit}()

All callers should still have RCU enabled.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Tony Lindgren <[email protected]>
Tested-by: Ulf Hansson <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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context_tracking: Take IRQ eqs entrypoints over RCU

The RCU dynticks counter is going to be merged into the context tracking
subsystem. Prepare with moving the IRQ extended quiescent states
entrypoi

context_tracking: Take IRQ eqs entrypoints over RCU

The RCU dynticks counter is going to be merged into the context tracking
subsystem. Prepare with moving the IRQ extended quiescent states
entrypoints to context tracking. For now those are dumb redirection to
existing RCU calls.

[ paulmck: Apply Stephen Rothwell feedback from -next. ]
[ paulmck: Apply Nathan Chancellor feedback. ]

Acked-by: Paul E. McKenney <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Neeraj Upadhyay <[email protected]>
Cc: Uladzislau Rezki <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Boqun Feng <[email protected]>
Cc: Nicolas Saenz Julienne <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: Xiongfeng Wang <[email protected]>
Cc: Yu Liao <[email protected]>
Cc: Phil Auld <[email protected]>
Cc: Paul Gortmaker<[email protected]>
Cc: Alex Belits <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Reviewed-by: Nicolas Saenz Julienne <[email protected]>
Tested-by: Nicolas Saenz Julienne <[email protected]>

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PM: cpu: Make notifier chain use a raw_spinlock_t

Invoking atomic_notifier_chain_notify() requires acquiring a spinlock_t,
which can block under CONFIG_PREEMPT_RT. Notifications for members of the
c

PM: cpu: Make notifier chain use a raw_spinlock_t

Invoking atomic_notifier_chain_notify() requires acquiring a spinlock_t,
which can block under CONFIG_PREEMPT_RT. Notifications for members of the
cpu_pm notification chain will be issued by the idle task, which can never
block.

Making *all* atomic_notifiers use a raw_spinlock is too big of a hammer, as
only notifications issued by the idle task are problematic.

Special-case cpu_pm_notifier_chain by kludging a raw_notifier and
raw_spinlock_t together, matching the atomic_notifier behavior with a
raw_spinlock_t.

Fixes: 70d932985757 ("notifier: Fix broken error handling pattern")
Signed-off-by: Valentin Schneider <[email protected]>
Acked-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

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notifier: Fix broken error handling pattern

The current notifiers have the following error handling pattern all
over the place:

int err, nr;

err = __foo_notifier_call_chain(&chain, val_up, v, -1

notifier: Fix broken error handling pattern

The current notifiers have the following error handling pattern all
over the place:

int err, nr;

err = __foo_notifier_call_chain(&chain, val_up, v, -1, &nr);
if (err & NOTIFIER_STOP_MASK)
__foo_notifier_call_chain(&chain, val_down, v, nr-1, NULL)

And aside from the endless repetition thereof, it is broken. Consider
blocking notifiers; both calls take and drop the rwsem, this means
that the notifier list can change in between the two calls, making @nr
meaningless.

Fix this by replacing all the __foo_notifier_call_chain() functions
with foo_notifier_call_chain_robust() that embeds the above pattern,
but ensures it is inside a single lock region.

Note: I switched atomic_notifier_call_chain_robust() to use
the spinlock, since RCU cannot provide the guarantee
required for the recovery.

Note: software_resume() error handling was broken afaict.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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kernel/cpu_pm: Fix uninitted local in cpu_pm

cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it

kernel/cpu_pm: Fix uninitted local in cpu_pm

cpu_pm_notify() is basically a wrapper of notifier_call_chain().
notifier_call_chain() doesn't initialize *nr_calls to 0 before it
starts incrementing it--presumably it's up to the callers to do this.

Unfortunately the callers of cpu_pm_notify() don't init *nr_calls.
This potentially means you could get too many or two few calls to
CPU_PM_ENTER_FAILED or CPU_CLUSTER_PM_ENTER_FAILED depending on the
luck of the stack.

Let's fix this.

Fixes: ab10023e0088 ("cpu_pm: Add cpu power management notifiers")
Cc: [email protected]
Cc: Rafael J. Wysocki <[email protected]>
Reviewed-by: Stephen Boyd <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
Link: https://lore.kernel.org/r/20200504104917.v6.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid
Signed-off-by: Bjorn Andersson <[email protected]>

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282

Based on 1 normalized pattern(s):

this software is licensed under the terms of the gnu general public
license version 2 as pub

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282

Based on 1 normalized pattern(s):

this software is licensed under the terms of the gnu general public
license version 2 as published by the free software foundation and
may be copied distributed and modified under those terms this
program is distributed in the hope that it will be useful but
without any warranty without even the implied warranty of
merchantability or fitness for a particular purpose see the gnu
general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 285 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexios Zavras <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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PM / CPU: replace raw_notifier with atomic_notifier

This patch replaces an rwlock and raw notifier by an atomic notifier
protected by a spin_lock and RCU.

The main reason for this change is due to

PM / CPU: replace raw_notifier with atomic_notifier

This patch replaces an rwlock and raw notifier by an atomic notifier
protected by a spin_lock and RCU.

The main reason for this change is due to a 'scheduling while atomic'
bug with RT kernels on ARM/ARM64. On ARM/ARM64, the rwlock
cpu_pm_notifier_lock in cpu_pm_enter/exit() causes a potential
schedule after IRQ disable in the idle call chain:

cpu_startup_entry
cpu_idle_loop
local_irq_disable()
cpuidle_idle_call
call_cpuidle
cpuidle_enter
cpuidle_enter_state
->enter :arm_enter_idle_state
cpu_pm_enter/exit
CPU_PM_CPU_IDLE_ENTER
read_lock(&cpu_pm_notifier_lock); <-- sleep in idle
__rt_spin_lock();
schedule();

The kernel panic is here:
[ 4.609601] BUG: scheduling while atomic: swapper/1/0/0x00000002
[ 4.609608] [<ffff0000086fae70>] arm_enter_idle_state+0x18/0x70
[ 4.609614] Modules linked in:
[ 4.609615] [<ffff0000086f9298>] cpuidle_enter_state+0xf0/0x218
[ 4.609620] [<ffff0000086f93f8>] cpuidle_enter+0x18/0x20
[ 4.609626] Preemption disabled at:
[ 4.609627] [<ffff0000080fa234>] call_cpuidle+0x24/0x40
[ 4.609635] [<ffff000008882fa4>] schedule_preempt_disabled+0x1c/0x28
[ 4.609639] [<ffff0000080fa49c>] cpu_startup_entry+0x154/0x1f8
[ 4.609645] [<ffff00000808e004>] secondary_start_kernel+0x15c/0x1a0

Daniel Lezcano said this notification is needed on arm/arm64 platforms.
Sebastian suggested using atomic_notifier instead of rwlock, which is not
only removing the sleeping in idle, but also improving latency.

Tony Lindgren found a miss use that rcu_read_lock used after rcu_idle_enter
Paul McKenney suggested trying RCU_NONIDLE.

Signed-off-by: Alex Shi <[email protected]>
Tested-by: Tony Lindgren <[email protected]>
Acked-by: Sebastian Andrzej Siewior <[email protected]>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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kernel/cpu_pm: fix cpu_cluster_pm_exit comment

cpu_cluster_pm_exit() must be sent after cpu_cluster_pm_enter() has been
sent for the cluster and before any cpu_pm_exit() notifications are sent
for a

kernel/cpu_pm: fix cpu_cluster_pm_exit comment

cpu_cluster_pm_exit() must be sent after cpu_cluster_pm_enter() has been
sent for the cluster and before any cpu_pm_exit() notifications are sent
for any CPU.

Cc: Nicolas Pitre <[email protected]>
Acked-by: Kevin Hilman <[email protected]>
Signed-off-by: Lina Iyer <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

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kernel/cpu_pm.c: fix various typos

Signed-off-by: Nicolas Pitre <[email protected]>
Acked-by: Colin Cross <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Signed-off-by: And

kernel/cpu_pm.c: fix various typos

Signed-off-by: Nicolas Pitre <[email protected]>
Acked-by: Colin Cross <[email protected]>
Acked-by: Santosh Shilimkar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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cpu_pm: call notifiers during suspend

Implements syscore_ops in cpu_pm to call the cpu and
cpu cluster notifiers during suspend and resume,
allowing drivers receiving the notifications to
avoid impl

cpu_pm: call notifiers during suspend

Implements syscore_ops in cpu_pm to call the cpu and
cpu cluster notifiers during suspend and resume,
allowing drivers receiving the notifications to
avoid implementing syscore_ops.

Signed-off-by: Colin Cross <[email protected]>
Signed-off-by: Santosh Shilimkar <[email protected]>
Reviewed-by: Kevin Hilman <[email protected]>
Tested-and-Acked-by: Shawn Guo <[email protected]>
Tested-by: Vishwanath BS <[email protected]>

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cpu_pm: Add cpu power management notifiers

During some CPU power modes entered during idle, hotplug and
suspend, peripherals located in the CPU power domain, such as
the GIC, localtimers, and VFP, m

cpu_pm: Add cpu power management notifiers

During some CPU power modes entered during idle, hotplug and
suspend, peripherals located in the CPU power domain, such as
the GIC, localtimers, and VFP, may be powered down. Add a
notifier chain that allows drivers for those peripherals to
be notified before and after they may be reset.

Notified drivers can include VFP co-processor, interrupt controller
and it's PM extensions, local CPU timers context save/restore which
shouldn't be interrupted. Hence CPU PM event APIs must be called
with interrupts disabled.

Signed-off-by: Colin Cross <[email protected]>
Signed-off-by: Santosh Shilimkar <[email protected]>
Reviewed-by: Kevin Hilman <[email protected]>
Tested-and-Acked-by: Shawn Guo <[email protected]>
Tested-by: Kevin Hilman <[email protected]>
Tested-by: Vishwanath BS <[email protected]>

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