Core changes:
- Provide IRQF_NO_AUTOEN as a flag for request*_irq() so drivers can be
cleaned up which either use a seperate mechanism to prevent auto-enable
at request time or have a racy mechanism which disables the interrupt
right after request.
- Get rid of the last usage of irq_create_identity_mapping() and remove
the interface.
- An overhaul of tasklet_disable(). Most usage sites of tasklet_disable()
are in task context and usually in cleanup, teardown code pathes.
tasklet_disable() spinwaits for a tasklet which is currently executed.
That's not only a problem for PREEMPT_RT where this can lead to a live
lock when the disabling task preempts the softirq thread. It's also
problematic in context of virtualization when the vCPU which runs the
tasklet is scheduled out and the disabling code has to spin wait until
it's scheduled back in. Though there are a few code pathes which invoke
tasklet_disable() from non-sleepable context. For these a new disable
variant which still spinwaits is provided which allows to switch
tasklet_disable() to a sleep wait mechanism. For the atomic use cases
this does not solve the live lock issue on PREEMPT_RT. That is mitigated
by blocking on the RT specific softirq lock.
- The PREEMPT_RT specific implementation of softirq processing and
local_bh_disable/enable().
On RT enabled kernels soft interrupt processing happens always in task
context and all interrupt handlers, which are not explicitly marked to
be invoked in hard interrupt context are forced into task context as
well. This allows to protect against softirq processing with a per
CPU lock, which in turn allows to make BH disabled regions preemptible.
Most of the softirq handling code is still shared. The RT/non-RT
specific differences are addressed with a set of inline functions which
provide the context specific functionality. The local_bh_disable() /
local_bh_enable() mechanism are obviously seperate.
- The usual set of small improvements and cleanups
Driver changes:
- New drivers for Nuvoton WPCM450 and DT 79rc3243x interrupt controllers
- Extended functionality for MStar, STM32 and SC7280 irq chips
- Enhanced robustness for ARM GICv3/4.1 drivers
- The usual set of cleanups and improvements all over the place
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Merge tag 'irq-core-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq updates from Thomas Gleixner:
"The usual updates from the irq departement:
Core changes:
- Provide IRQF_NO_AUTOEN as a flag for request*_irq() so drivers can
be cleaned up which either use a seperate mechanism to prevent
auto-enable at request time or have a racy mechanism which disables
the interrupt right after request.
- Get rid of the last usage of irq_create_identity_mapping() and
remove the interface.
- An overhaul of tasklet_disable().
Most usage sites of tasklet_disable() are in task context and
usually in cleanup, teardown code pathes. tasklet_disable()
spinwaits for a tasklet which is currently executed. That's not
only a problem for PREEMPT_RT where this can lead to a live lock
when the disabling task preempts the softirq thread. It's also
problematic in context of virtualization when the vCPU which runs
the tasklet is scheduled out and the disabling code has to spin
wait until it's scheduled back in.
There are a few code pathes which invoke tasklet_disable() from
non-sleepable context. For these a new disable variant which still
spinwaits is provided which allows to switch tasklet_disable() to a
sleep wait mechanism. For the atomic use cases this does not solve
the live lock issue on PREEMPT_RT. That is mitigated by blocking on
the RT specific softirq lock.
- The PREEMPT_RT specific implementation of softirq processing and
local_bh_disable/enable().
On RT enabled kernels soft interrupt processing happens always in
task context and all interrupt handlers, which are not explicitly
marked to be invoked in hard interrupt context are forced into task
context as well. This allows to protect against softirq processing
with a per CPU lock, which in turn allows to make BH disabled
regions preemptible.
Most of the softirq handling code is still shared. The RT/non-RT
specific differences are addressed with a set of inline functions
which provide the context specific functionality. The
local_bh_disable() / local_bh_enable() mechanism are obviously
seperate.
- The usual set of small improvements and cleanups
Driver changes:
- New drivers for Nuvoton WPCM450 and DT 79rc3243x interrupt
controllers
- Extended functionality for MStar, STM32 and SC7280 irq chips
- Enhanced robustness for ARM GICv3/4.1 drivers
- The usual set of cleanups and improvements all over the place"
* tag 'irq-core-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
irqchip/xilinx: Expose Kconfig option for Zynq/ZynqMP
irqchip/gic-v3: Do not enable irqs when handling spurious interrups
dt-bindings: interrupt-controller: Add IDT 79RC3243x Interrupt Controller
irqchip: Add support for IDT 79rc3243x interrupt controller
irqdomain: Drop references to recusive irqdomain setup
irqdomain: Get rid of irq_create_strict_mappings()
irqchip/jcore-aic: Kill use of irq_create_strict_mappings()
ARM: PXA: Kill use of irq_create_strict_mappings()
irqchip/gic-v4.1: Disable vSGI upon (GIC CPUIF < v4.1) detection
irqchip/tb10x: Use 'fallthrough' to eliminate a warning
genirq: Reduce irqdebug cacheline bouncing
kernel: Initialize cpumask before parsing
irqchip/wpcm450: Drop COMPILE_TEST
irqchip/irq-mst: Support polarity configuration
irqchip: Add driver for WPCM450 interrupt controller
dt-bindings: interrupt-controller: Add nuvoton, wpcm450-aic
dt-bindings: qcom,pdc: Add compatible for sc7280
irqchip/stm32: Add usart instances exti direct event support
irqchip/gic-v3: Fix OF_BAD_ADDR error handling
irqchip/sifive-plic: Mark two global variables __ro_after_init
...
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