After commit 0edb555a65 ("platform: Make platform_driver::remove()
return void") .remove() is (again) the right callback to implement for
platform drivers.
Convert all platform drivers below drivers/perf to use .remove(), with
the eventual goal to drop struct platform_driver::remove_new(). As
.remove() and .remove_new() have the same prototypes, conversion is done
by just changing the structure member name in the driver initializer.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20241027180313.410964-2-u.kleine-koenig@baylibre.com
Signed-off-by: Will Deacon <will@kernel.org>
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20cc24ede88f5e000991dfe6f4cf1222b819e337.1702648125.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Will Deacon <will@kernel.org>
The following circular locking dependency was reported when running
cpus online/offline test on an arm64 system.
[ 84.195923] Chain exists of:
dmc620_pmu_irqs_lock --> cpu_hotplug_lock --> cpuhp_state-down
[ 84.207305] Possible unsafe locking scenario:
[ 84.213212] CPU0 CPU1
[ 84.217729] ---- ----
[ 84.222247] lock(cpuhp_state-down);
[ 84.225899] lock(cpu_hotplug_lock);
[ 84.232068] lock(cpuhp_state-down);
[ 84.238237] lock(dmc620_pmu_irqs_lock);
[ 84.242236]
*** DEADLOCK ***
The following locking order happens when dmc620_pmu_get_irq() calls
cpuhp_state_add_instance_nocalls().
lock(dmc620_pmu_irqs_lock) --> lock(cpu_hotplug_lock)
On the other hand, the calling sequence
cpuhp_thread_fun()
=> cpuhp_invoke_callback()
=> dmc620_pmu_cpu_teardown()
leads to the locking sequence
lock(cpuhp_state-down) => lock(dmc620_pmu_irqs_lock)
Here dmc620_pmu_irqs_lock protects both the dmc620_pmu_irqs and the
pmus_node lists in various dmc620_pmu instances. dmc620_pmu_get_irq()
requires protected access to dmc620_pmu_irqs whereas
dmc620_pmu_cpu_teardown() needs protection to the pmus_node lists.
Break this circular locking dependency by using two separate locks to
protect dmc620_pmu_irqs list and the pmus_node lists respectively.
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20230812235549.494174-1-longman@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
The driver uses irq_set_affinity_hint() to set the affinity for the PMU
interrupts, which relies on the undocumented side effect that this function
actually sets the affinity under the hood.
Setting an hint is clearly not a guarantee and for these PMU interrupts an
affinity hint, which is supposed to guide userspace for setting affinity,
is beyond pointless, because the affinity of these interrupts cannot be
modified from user space.
Aside of that the error checks are bogus because the only error which is
returned from irq_set_affinity_hint() is when there is no irq descriptor
for the interrupt number, but not when the affinity set fails. That's on
purpose because the hint can point to an offline CPU.
Replace the mindless abuse with irq_set_affinity().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210518093118.395086573@linutronix.de
Signed-off-by: Will Deacon <will@kernel.org>
DMC-620 PMU supports total 10 counters which each is
independently programmable to different events and can
be started and stopped individually.
Currently, it only supports ACPI. Other platforms feel free to test and add
support for device tree.
Usage example:
#perf stat -e arm_dmc620_10008c000/clk_cycle_count/ -C 0
Get perf event for clk_cycle_count counter.
#perf stat -e arm_dmc620_10008c000/clkdiv2_allocate,mask=0x1f,match=0x2f,
incr=2,invert=1/ -C 0
The above example shows how to specify mask, match, incr,
invert parameters for clkdiv2_allocate event.
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Tuan Phan <tuanphan@os.amperecomputing.com>
Link: https://lore.kernel.org/r/1604518246-6198-1-git-send-email-tuanphan@os.amperecomputing.com
Signed-off-by: Will Deacon <will@kernel.org>
