01 Sep, 2020
1 commit
-
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)
Signed-off-by: Ingo Molnar
Acked-by: Rafael J. Wysocki
Link: https://lore.kernel.org/r/20200818135804.325626653@infradead.org
16 May, 2020
1 commit
-
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: stable@vger.kernel.org
Cc: Rafael J. Wysocki
Reviewed-by: Stephen Boyd
Reviewed-by: Greg Kroah-Hartman
Signed-off-by: Douglas Anderson
Link: https://lore.kernel.org/r/20200504104917.v6.3.I2d44fc0053d019f239527a4e5829416714b7e299@changeid
Signed-off-by: Bjorn Andersson
05 Jun, 2019
1 commit
-
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 detailsextracted 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
Reviewed-by: Alexios Zavras
Reviewed-by: Allison Randal
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141900.642774971@linutronix.de
Signed-off-by: Greg Kroah-Hartman
31 Jul, 2017
1 commit
-
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); ] arm_enter_idle_state+0x18/0x70
[ 4.609614] Modules linked in:
[ 4.609615] [] cpuidle_enter_state+0xf0/0x218
[ 4.609620] [] cpuidle_enter+0x18/0x20
[ 4.609626] Preemption disabled at:
[ 4.609627] [] call_cpuidle+0x24/0x40
[ 4.609635] [] schedule_preempt_disabled+0x1c/0x28
[ 4.609639] [] cpu_startup_entry+0x154/0x1f8
[ 4.609645] [] secondary_start_kernel+0x15c/0x1a0Daniel 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
Tested-by: Tony Lindgren
Acked-by: Sebastian Andrzej Siewior
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki
03 Sep, 2015
1 commit
-
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
Acked-by: Kevin Hilman
Signed-off-by: Lina Iyer
Signed-off-by: Rafael J. Wysocki
01 Jun, 2012
1 commit
-
Signed-off-by: Nicolas Pitre
Acked-by: Colin Cross
Acked-by: Santosh Shilimkar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Sep, 2011
2 commits
-
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
Signed-off-by: Santosh Shilimkar
Reviewed-by: Kevin Hilman
Tested-and-Acked-by: Shawn Guo
Tested-by: Vishwanath BS -
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
Signed-off-by: Santosh Shilimkar
Reviewed-by: Kevin Hilman
Tested-and-Acked-by: Shawn Guo
Tested-by: Kevin Hilman
Tested-by: Vishwanath BS
