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* kthread: add kthread_stop_putAndreas Gruenbacher2023-10-041-10/+5
| | | | | | | | | | | | | | | | Add a kthread_stop_put() helper that stops a thread and puts its task struct. Use it to replace the various instances of kthread_stop() followed by put_task_struct(). Remove the kthread_stop_put() macro in usbip that is similar but doesn't return the result of kthread_stop(). [agruenba@redhat.com: fix kerneldoc comment] Link: https://lkml.kernel.org/r/20230911111730.2565537-1-agruenba@redhat.com [akpm@linux-foundation.org: document kthread_stop_put()'s argument] Link: https://lkml.kernel.org/r/20230907234048.2499820-1-agruenba@redhat.com Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* genirq: Prevent nested thread vs synchronize_hardirq() deadlockVincent Whitchurch2023-07-311-12/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a possibility of deadlock if synchronize_hardirq() is called when the nested threaded interrupt is active. The following scenario was observed on a uniprocessor PREEMPT_NONE system: Thread 1 Thread 2 handle_nested_thread() Set INPROGRESS Call ->thread_fn() thread_fn goes to sleep free_irq() __synchronize_hardirq() Busy-loop forever waiting for INPROGRESS to be cleared The INPROGRESS flag is only supposed to be used for hard interrupt handlers. Remove the incorrect usage in the nested threaded interrupt case and instead re-use the threads_active / wait_for_threads mechanism to wait for nested threaded interrupts to complete. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230613-genirq-nested-v3-1-ae58221143eb@axis.com
* genirq: Update affinity of secondary threadsJohn Keeping2023-04-151-1/+4
| | | | | | | | | | | | | | For interrupts with secondary threads, the affinity is applied when the thread is created but if the interrupts affinity is changed later only the primary thread is updated. Update the secondary thread's affinity as well to keep all the interrupts activity on the assigned CPUs. Signed-off-by: John Keeping <john@metanate.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230406180857.588682-1-john@metanate.com
* genirq: Add might_sleep() to disable_irq()Manfred Spraul2023-01-111-1/+4
| | | | | | | | | | | | | | | | With the introduction of threaded interrupt handlers, it is virtually never safe to call disable_irq() from non-premptible context. Thus: Update the documentation, add an explicit might_sleep() to catch any offenders. This is more obvious and straight forward than the implicit might_sleep() check deeper down in the disable_irq() call chain. Fixes: 3aa551c9b4c4 ("genirq: add threaded interrupt handler support") Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20221216150441.200533-3-manfred@colorfullife.com
* genirq: Remove unused argument force of irq_set_affinity_deactivated()Angus Chen2022-11-171-2/+2
| | | | | | | | | The force parameter in irq_set_affinity_deactivated() is not used, get rid of it. Signed-off-by: Angus Chen <angus.chen@jaguarmicro.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20221007103236.599-1-angus.chen@jaguarmicro.com
* genirq: Drop redundant irq_init_effective_affinitySamuel Holland2022-07-071-9/+1
| | | | | | | | It does exactly the same thing as irq_data_update_effective_affinity. Signed-off-by: Samuel Holland <samuel@sholland.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220701200056.46555-5-samuel@sholland.org
* Merge tag 'irq-core-2022-05-23' of ↵Linus Torvalds2022-05-231-8/+23
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull interrupt handling updates from Thomas Gleixner: "Core code: - Make the managed interrupts more robust by shutting them down in the core code when the assigned affinity mask does not contain online CPUs. - Make the irq simulator chip work on RT - A small set of cpumask and power manageent cleanups Drivers: - A set of changes which mark GPIO interrupt chips immutable to prevent the GPIO subsystem from modifying it under the hood. This provides the necessary infrastructure and converts a set of GPIO and pinctrl drivers over. - A set of changes to make the pseudo-NMI handling for GICv3 more robust: a missing barrier and consistent handling of the priority mask. - Another set of GICv3 improvements and fixes, but nothing outstanding - The usual set of improvements and cleanups all over the place - No new irqchip drivers and not even a new device tree binding! 100+ interrupt chips are truly enough" * tag 'irq-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits) irqchip: Add Kconfig symbols for sunxi drivers irqchip/gic-v3: Fix priority mask handling irqchip/gic-v3: Refactor ISB + EOIR at ack time irqchip/gic-v3: Ensure pseudo-NMIs have an ISB between ack and handling genirq/irq_sim: Make the irq_work always run in hard irq context irqchip/armada-370-xp: Do not touch Performance Counter Overflow on A375, A38x, A39x irqchip/gic: Improved warning about incorrect type irqchip/csky: Return true/false (not 1/0) from bool functions irqchip/imx-irqsteer: Add runtime PM support irqchip/imx-irqsteer: Constify irq_chip struct irqchip/armada-370-xp: Enable MSI affinity configuration irqchip/aspeed-scu-ic: Fix irq_of_parse_and_map() return value irqchip/aspeed-i2c-ic: Fix irq_of_parse_and_map() return value irqchip/sun6i-r: Use NULL for chip_data irqchip/xtensa-mx: Fix initial IRQ affinity in non-SMP setup irqchip/exiu: Fix acknowledgment of edge triggered interrupts irqchip/gic-v3: Claim iomem resources dt-bindings: interrupt-controller: arm,gic-v3: Make the v2 compat requirements explicit irqchip/gic-v3: Relax polling of GIC{R,D}_CTLR.RWP irqchip/gic-v3: Detect LPI invalidation MMIO registers ...
| * genirq: Take the proposed affinity at face value if force==trueMarc Zyngier2022-04-141-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although setting the affinity of an interrupt to a set of CPUs that doesn't have any online CPU is generally frowned apon, there are a few limited cases where such affinity is set from a CPUHP notifier, setting the affinity to a CPU that isn't online yet. The saving grace is that this is always done using the 'force' attribute, which gives a hint that the affinity setting can be outside of the online CPU mask and the callsite set this flag with the knowledge that the underlying interrupt controller knows to handle it. This restores the expected behaviour on Marek's system. Fixes: 33de0aa4bae9 ("genirq: Always limit the affinity to online CPUs") Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/4b7fc13c-887b-a664-26e8-45aed13f048a@samsung.com Link: https://lore.kernel.org/r/20220414140011.541725-1-maz@kernel.org
| * genirq: Always limit the affinity to online CPUsMarc Zyngier2022-04-101-8/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When booting with maxcpus=<small number> (or even loading a driver while most CPUs are offline), it is pretty easy to observe managed affinities containing a mix of online and offline CPUs being passed to the irqchip driver. This means that the irqchip cannot trust the affinity passed down from the core code, which is a bit annoying and requires (at least in theory) all drivers to implement some sort of affinity narrowing. In order to address this, always limit the cpumask to the set of online CPUs. Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20220405185040.206297-3-maz@kernel.org
* | genirq: Synchronize interrupt thread startupThomas Pfaff2022-05-051-10/+29
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A kernel hang can be observed when running setserial in a loop on a kernel with force threaded interrupts. The sequence of events is: setserial open("/dev/ttyXXX") request_irq() do_stuff() -> serial interrupt -> wake(irq_thread) desc->threads_active++; close() free_irq() kthread_stop(irq_thread) synchronize_irq() <- hangs because desc->threads_active != 0 The thread is created in request_irq() and woken up, but does not get on a CPU to reach the actual thread function, which would handle the pending wake-up. kthread_stop() sets the should stop condition which makes the thread immediately exit, which in turn leaves the stale threads_active count around. This problem was introduced with commit 519cc8652b3a, which addressed a interrupt sharing issue in the PCIe code. Before that commit free_irq() invoked synchronize_irq(), which waits for the hard interrupt handler and also for associated threads to complete. To address the PCIe issue synchronize_irq() was replaced with __synchronize_hardirq(), which only waits for the hard interrupt handler to complete, but not for threaded handlers. This was done under the assumption, that the interrupt thread already reached the thread function and waits for a wake-up, which is guaranteed to be handled before acting on the stop condition. The problematic case, that the thread would not reach the thread function, was obviously overlooked. Make sure that the interrupt thread is really started and reaches thread_fn() before returning from __setup_irq(). This utilizes the existing wait queue in the interrupt descriptor. The wait queue is unused for non-shared interrupts. For shared interrupts the usage might cause a spurious wake-up of a waiter in synchronize_irq() or the completion of a threaded handler might cause a spurious wake-up of the waiter for the ready flag. Both are harmless and have no functional impact. [ tglx: Amended changelog ] Fixes: 519cc8652b3a ("genirq: Synchronize only with single thread on free_irq()") Signed-off-by: Thomas Pfaff <tpfaff@pcs.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/552fe7b4-9224-b183-bb87-a8f36d335690@pcs.com
* sched/isolation: Use single feature type while referring to housekeeping cpumaskFrederic Weisbecker2022-02-161-2/+2
| | | | | | | | | | | | | Refer to housekeeping APIs using single feature types instead of flags. This prevents from passing multiple isolation features at once to housekeeping interfaces, which soon won't be possible anymore as each isolation features will have their own cpumask. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Juri Lelli <juri.lelli@redhat.com> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://lore.kernel.org/r/20220207155910.527133-5-frederic@kernel.org
* genirq: Provide new interfaces for affinity hintsThomas Gleixner2021-12-101-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The discussion about removing the side effect of irq_set_affinity_hint() of actually applying the cpumask (if not NULL) as affinity to the interrupt, unearthed a few unpleasantries: 1) The modular perf drivers rely on the current behaviour for the very wrong reasons. 2) While none of the other drivers prevents user space from changing the affinity, a cursorily inspection shows that there are at least expectations in some drivers. #1 needs to be cleaned up anyway, so that's not a problem #2 might result in subtle regressions especially when irqbalanced (which nowadays ignores the affinity hint) is disabled. Provide new interfaces: irq_update_affinity_hint() - Only sets the affinity hint pointer irq_set_affinity_and_hint() - Set the pointer and apply the affinity to the interrupt Make irq_set_affinity_hint() a wrapper around irq_apply_affinity_hint() and document it to be phased out. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210501021832.743094-1-jesse.brandeburg@intel.com Link: https://lore.kernel.org/r/20210903152430.244937-2-nitesh@redhat.com
* genirq: Move prio assignment into the newly created threadThomas Gleixner2021-09-171-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With enabled threaded interrupts the nouveau driver reported the following: | Chain exists of: | &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem | | Possible unsafe locking scenario: | | CPU0 CPU1 | ---- ---- | lock(&cpuset_rwsem); | lock(&device->mutex); | lock(&cpuset_rwsem); | lock(&mm->mmap_lock#2); The device->mutex is nvkm_device::mutex. Unblocking the lockchain at `cpuset_rwsem' is probably the easiest thing to do. Move the priority assignment to the start of the newly created thread. Fixes: 710da3c8ea7df ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()") Reported-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [bigeasy: Patch description] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de
* genirq: Update irq_set_irqchip_state documentationJosh Cartwright2021-09-171-1/+1
| | | | | | | | | | | | On RT kernels, the use of migrate_disable()/migrate_enable() is sufficient to guarantee a task isn't moved to another CPU. Update the irq_set_irqchip_state() documentation to reflect this. Signed-off-by: Josh Cartwright <joshc@ni.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210917103055.92150-1-bigeasy@linutronix.de
* genirq: Fix kernel doc indentationThomas Gleixner2021-08-131-3/+1
| | | | | | Fixes: 61377ec14457 ("genirq: Clarify documentation for request_threaded_irq()") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* genirq: Change force_irqthreads to a static keyTanner Love2021-08-101-6/+5
| | | | | | | | | | | | | | | | | With CONFIG_IRQ_FORCED_THREADING=y, testing the boolean force_irqthreads could incur a cache line miss in invoke_softirq() and other places. Replace the test with a static key to avoid the potential cache miss. [ tglx: Dropped the IDE part, removed the export and updated blk-mq ] Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Tanner Love <tannerlove@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210602180338.3324213-1-tannerlove.kernel@gmail.com
* genirq: Clarify documentation for request_threaded_irq()Joel Savitz2021-08-101-3/+5
| | | | | | | | | Clarify wording and document commonly used IRQF_ONESHOT flag. Signed-off-by: Joel Savitz <jsavitz@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210731050740.444454-1-jsavitz@redhat.com
* Merge branch 'irq/affinity' into irq/coreThomas Gleixner2021-05-191-1/+32
|\ | | | | | | | | Merge the export of irq_set_affinity() which is a standalone commit so it can be pulled into other trees.
| * genirq: Export affinity setter for modulesThomas Gleixner2021-05-191-1/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Perf modules abuse irq_set_affinity_hint() to set the affinity of system PMU interrupts just because irq_set_affinity() was not exported. The fact that irq_set_affinity_hint() actually sets the affinity is a non-documented side effect and the name is clearly saying it's a hint. To clean this up, export the real affinity setter. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210518093117.968251441@linutronix.de
* | genirq: Add a IRQF_NO_DEBUG flagThomas Gleixner2021-05-171-0/+5
|/ | | | | | | | | | | | | | | | | | | | The whole call to note_interrupt() can be avoided or return early when interrupts would be marked accordingly. For IPI handlers which always return HANDLED the whole procedure is pretty pointless to begin with. Add a IRQF_NO_DEBUG flag and mark the interrupt accordingly if supplied when the interrupt is requested. When noirqdebug is set on the kernel commandline, then the interrupt is marked unconditionally so that there is only one condition in the hotpath to evaluate. [ clg: Add changelog ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/7a8ad02f-63a8-c1aa-fdd1-39d973593d02@kaod.org
* Merge tag 'irq-core-2021-04-26' of ↵Linus Torvalds2021-04-261-8/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ...
| * irq: Fix typos in commentsIngo Molnar2021-03-221-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | Fix ~36 single-word typos in the IRQ, irqchip and irqdomain code comments. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Marc Zyngier <maz@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * genirq: Fix typos and misspellings in commentsKrzysztof Kozlowski2021-03-161-3/+3
| | | | | | | | | | | | | | | | | | No functional change. Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210316100205.23492-1-krzysztof.kozlowski@canonical.com
| * genirq: Add IRQF_NO_AUTOEN for request_irq/nmi()Barry Song2021-03-061-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many drivers don't want interrupts enabled automatically via request_irq(). So they are handling this issue by either way of the below two: (1) irq_set_status_flags(irq, IRQ_NOAUTOEN); request_irq(dev, irq...); (2) request_irq(dev, irq...); disable_irq(irq); The code in the second way is silly and unsafe. In the small time gap between request_irq() and disable_irq(), interrupts can still come. The code in the first way is safe though it's subobtimal. Add a new IRQF_NO_AUTOEN flag which can be handed in by drivers to request_irq() and request_nmi(). It prevents the automatic enabling of the requested interrupt/nmi in the same safe way as #1 above. With that the various usage sites of #1 and #2 above can be simplified and corrected. Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: dmitry.torokhov@gmail.com Link: https://lore.kernel.org/r/20210302224916.13980-2-song.bao.hua@hisilicon.com
* | genirq: Disable interrupts for force threaded handlersThomas Gleixner2021-03-211-0/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With interrupt force threading all device interrupt handlers are invoked from kernel threads. Contrary to hard interrupt context the invocation only disables bottom halfs, but not interrupts. This was an oversight back then because any code like this will have an issue: thread(irq_A) irq_handler(A) spin_lock(&foo->lock); interrupt(irq_B) irq_handler(B) spin_lock(&foo->lock); This has been triggered with networking (NAPI vs. hrtimers) and console drivers where printk() happens from an interrupt which interrupted the force threaded handler. Now people noticed and started to change the spin_lock() in the handler to spin_lock_irqsave() which affects performance or add IRQF_NOTHREAD to the interrupt request which in turn breaks RT. Fix the root cause and not the symptom and disable interrupts before invoking the force threaded handler which preserves the regular semantics and the usefulness of the interrupt force threading as a general debugging tool. For not RT this is not changing much, except that during the execution of the threaded handler interrupts are delayed until the handler returns. Vs. scheduling and softirq processing there is no difference. For RT kernels there is no issue. Fixes: 8d32a307e4fa ("genirq: Provide forced interrupt threading") Reported-by: Johan Hovold <johan@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Johan Hovold <johan@kernel.org> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20210317143859.513307808@linutronix.de
* genirq: Export irq_check_status_bit()Thomas Gleixner2021-01-131-0/+1
| | | | | | | | | | | One of the users can be built modular: ERROR: modpost: "irq_check_status_bit" [drivers/perf/arm_spe_pmu.ko] undefined! Fixes: fdd029630434 ("genirq: Move status flag checks to core") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201227192049.GA195845@roeck-us.net
* genirq: Move status flag checks to coreThomas Gleixner2020-12-151-0/+20
| | | | | | | | | | These checks are used by modules and prevent the removal of the export of irq_to_desc(). Move the accessor into the core. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201210194042.703779349@linutronix.de
* genirq: Move irq_has_action() into core codeThomas Gleixner2020-12-151-0/+17
| | | | | | | | | | | | | | This function uses irq_to_desc() and is going to be used by modules to replace the open coded irq_to_desc() (ab)usage. The final goal is to remove the export of irq_to_desc() so driver cannot fiddle with it anymore. Move it into the core code and fixup the usage sites to include the proper header. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201210194042.548936472@linutronix.de
* genirq/affinity: Add irq_update_affinity_desc()John Garry2020-12-111-0/+70
| | | | | | | | | | | | | | | | | | | | Add a function to allow the affinity of an interrupt be switched to managed, such that interrupts allocated for platform devices may be managed. This new interface has certain limitations, and attempts to use it in the following circumstances will fail: - For when the kernel is configured for generic IRQ reservation mode (in config GENERIC_IRQ_RESERVATION_MODE). The reason being that it could conflict with managed vs. non-managed interrupt accounting. - The interrupt is already started, which should not be the case during init - The interrupt is already configured as managed, which means double init Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Garry <john.garry@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/1606905417-183214-2-git-send-email-john.garry@huawei.com
* task_work: cleanup notification modesJens Axboe2020-10-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | A previous commit changed the notification mode from true/false to an int, allowing notify-no, notify-yes, or signal-notify. This was backwards compatible in the sense that any existing true/false user would translate to either 0 (on notification sent) or 1, the latter which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2. Clean this up properly, and define a proper enum for the notification mode. Now we have: - TWA_NONE. This is 0, same as before the original change, meaning no notification requested. - TWA_RESUME. This is 1, same as before the original change, meaning that we use TIF_NOTIFY_RESUME. - TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the notification. Clean up all the callers, switching their 0/1/false/true to using the appropriate TWA_* mode for notifications. Fixes: e91b48162332 ("task_work: teach task_work_add() to do signal_wake_up()") Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva2020-08-231-2/+2
| | | | | | | | | | Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
* genirq: Unlock irq descriptor after errorsGuenter Roeck2020-08-131-2/+5
| | | | | | | | | | | | | In irq_set_irqchip_state(), the irq descriptor is not unlocked after an error is encountered. While that should never happen in practice, a buggy driver may trigger it. This would result in a lockup, so fix it. Fixes: 1d0326f352bb ("genirq: Check irq_data_get_irq_chip() return value before use") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200811180012.80269-1-linux@roeck-us.net
* Merge tag 'sched-fifo-2020-08-04' of ↵Linus Torvalds2020-08-061-5/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull sched/fifo updates from Ingo Molnar: "This adds the sched_set_fifo*() encapsulation APIs to remove static priority level knowledge from non-scheduler code. The three APIs for non-scheduler code to set SCHED_FIFO are: - sched_set_fifo() - sched_set_fifo_low() - sched_set_normal() These are two FIFO priority levels: default (high), and a 'low' priority level, plus sched_set_normal() to set the policy back to non-SCHED_FIFO. Since the changes affect a lot of non-scheduler code, we kept this in a separate tree" * tag 'sched-fifo-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) sched,tracing: Convert to sched_set_fifo() sched: Remove sched_set_*() return value sched: Remove sched_setscheduler*() EXPORTs sched,psi: Convert to sched_set_fifo_low() sched,rcutorture: Convert to sched_set_fifo_low() sched,rcuperf: Convert to sched_set_fifo_low() sched,locktorture: Convert to sched_set_fifo() sched,irq: Convert to sched_set_fifo() sched,watchdog: Convert to sched_set_fifo() sched,serial: Convert to sched_set_fifo() sched,powerclamp: Convert to sched_set_fifo() sched,ion: Convert to sched_set_normal() sched,powercap: Convert to sched_set_fifo*() sched,spi: Convert to sched_set_fifo*() sched,mmc: Convert to sched_set_fifo*() sched,ivtv: Convert to sched_set_fifo*() sched,drm/scheduler: Convert to sched_set_fifo*() sched,msm: Convert to sched_set_fifo*() sched,psci: Convert to sched_set_fifo*() sched,drbd: Convert to sched_set_fifo*() ...
| * sched,irq: Convert to sched_set_fifo()Peter Zijlstra2020-06-151-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | Because SCHED_FIFO is a broken scheduler model (see previous patches) take away the priority field, the kernel can't possibly make an informed decision. Effectively no change. Cc: tglx@linutronix.de Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org>
* | genirq/affinity: Make affinity setting if activated opt-inThomas Gleixner2020-07-271-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | John reported that on a RK3288 system the perf per CPU interrupts are all affine to CPU0 and provided the analysis: "It looks like what happens is that because the interrupts are not per-CPU in the hardware, armpmu_request_irq() calls irq_force_affinity() while the interrupt is deactivated and then request_irq() with IRQF_PERCPU | IRQF_NOBALANCING. Now when irq_startup() runs with IRQ_STARTUP_NORMAL, it calls irq_setup_affinity() which returns early because IRQF_PERCPU and IRQF_NOBALANCING are set, leaving the interrupt on its original CPU." This was broken by the recent commit which blocked interrupt affinity setting in hardware before activation of the interrupt. While this works in general, it does not work for this particular case. As contrary to the initial analysis not all interrupt chip drivers implement an activate callback, the safe cure is to make the deferred interrupt affinity setting at activation time opt-in. Implement the necessary core logic and make the two irqchip implementations for which this is required opt-in. In hindsight this would have been the right thing to do, but ... Fixes: baedb87d1b53 ("genirq/affinity: Handle affinity setting on inactive interrupts correctly") Reported-by: John Keeping <john@metanate.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marc Zyngier <maz@kernel.org> Acked-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/87blk4tzgm.fsf@nanos.tec.linutronix.de
* | genirq/affinity: Handle affinity setting on inactive interrupts correctlyThomas Gleixner2020-07-171-2/+35
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Setting interrupt affinity on inactive interrupts is inconsistent when hierarchical irq domains are enabled. The core code should just store the affinity and not call into the irq chip driver for inactive interrupts because the chip drivers may not be in a state to handle such requests. X86 has a hacky workaround for that but all other irq chips have not which causes problems e.g. on GIC V3 ITS. Instead of adding more ugly hacks all over the place, solve the problem in the core code. If the affinity is set on an inactive interrupt then: - Store it in the irq descriptors affinity mask - Update the effective affinity to reflect that so user space has a consistent view - Don't call into the irq chip driver This is the core equivalent of the X86 workaround and works correctly because the affinity setting is established in the irq chip when the interrupt is activated later on. Note, that this is only effective when hierarchical irq domains are enabled by the architecture. Doing it unconditionally would break legacy irq chip implementations. For hierarchial irq domains this works correctly as none of the drivers can have a dependency on affinity setting in inactive state by design. Remove the X86 workaround as it is not longer required. Fixes: 02edee152d6e ("x86/apic/vector: Ignore set_affinity call for inactive interrupts") Reported-by: Ali Saidi <alisaidi@amazon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Ali Saidi <alisaidi@amazon.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200529015501.15771-1-alisaidi@amazon.com Link: https://lkml.kernel.org/r/877dv2rv25.fsf@nanos.tec.linutronix.de
* genirq: Check irq_data_get_irq_chip() return value before useMarek Vasut2020-05-281-0/+4
| | | | | | | | | | | irq_data_get_irq_chip() can return NULL, however it is expected that this never happens. If a buggy driver leads to NULL being returned from irq_data_get_irq_chip(), warn about it instead of crashing the machine. Signed-off-by: Marek Vasut <marex@denx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> To: linux-arm-kernel@lists.infradead.org
* genirq: Remove setup_irq() and remove_irq()afzal mohammed2020-04-141-44/+0
| | | | | | | | | | | Now that all the users of setup_irq() & remove_irq() have been replaced by request_irq() & free_irq() respectively, delete them. Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lkml.kernel.org/r/0aa8771ada1ac8e1312f6882980c9c08bd023148.1585320721.git.afzal.mohd.ma@gmail.com
* genirq: Fix reference leaks on irq affinity notifiersEdward Cree2020-03-211-2/+9
| | | | | | | | | | | | | | | | | | | | | | The handling of notify->work did not properly maintain notify->kref in two cases: 1) where the work was already scheduled, another irq_set_affinity_locked() would get the ref and (no-op-ly) schedule the work. Thus when irq_affinity_notify() ran, it would drop the original ref but not the additional one. 2) when cancelling the (old) work in irq_set_affinity_notifier(), if there was outstanding work a ref had been got for it but was never put. Fix both by checking the return values of the work handling functions (schedule_work() for (1) and cancel_work_sync() for (2)) and put the extra ref if the return value indicates preexisting work. Fixes: cd7eab44e994 ("genirq: Add IRQ affinity notifiers") Fixes: 59c39840f5ab ("genirq: Prevent use-after-free and work list corruption") Signed-off-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ben Hutchings <ben@decadent.org.uk> Link: https://lkml.kernel.org/r/24f5983f-2ab5-e83a-44ee-a45b5f9300f5@solarflare.com
* genirq/proc: Reject invalid affinity masks (again)Thomas Gleixner2020-02-141-16/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Qian Cai reported that the WARN_ON() in the x86/msi affinity setting code, which catches cases where the affinity setting is not done on the CPU which is the current target of the interrupt, triggers during CPU hotplug stress testing. It turns out that the warning which was added with the commit addressing the MSI affinity race unearthed yet another long standing bug. If user space writes a bogus affinity mask, i.e. it contains no online CPUs, then it calls irq_select_affinity_usr(). This was introduced for ALPHA in eee45269b0f5 ("[PATCH] Alpha: convert to generic irq framework (generic part)") and subsequently made available for all architectures in 18404756765c ("genirq: Expose default irq affinity mask (take 3)") which introduced the circumvention of the affinity setting restrictions for interrupt which cannot be moved in process context. The whole exercise is bogus in various aspects: 1) If the interrupt is already started up then there is absolutely no point to honour a bogus interrupt affinity setting from user space. The interrupt is already assigned to an online CPU and it does not make any sense to reassign it to some other randomly chosen online CPU. 2) If the interupt is not yet started up then there is no point either. A subsequent startup of the interrupt will invoke irq_setup_affinity() anyway which will chose a valid target CPU. So the only correct solution is to just return -EINVAL in case user space wrote an affinity mask which does not contain any online CPUs, except for ALPHA which has it's own magic sauce for this. Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)") Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Qian Cai <cai@lca.pw> Link: https://lkml.kernel.org/r/878sl8xdbm.fsf@nanos.tec.linutronix.de
* genirq: Clarify that irq wake state is orthogonal to enable/disableStephen Boyd2020-02-071-0/+7
| | | | | | | | | | | | | | | There's some confusion around if an irq that's disabled with disable_irq() can still wake the system from sleep states such as "suspend to RAM". Clarify this in the kernel documentation for irq_set_irq_wake() so that it's clear that an irq can be disabled and still wake the system if it has been marked for wakeup. Signed-off-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lkml.kernel.org/r/20200206191521.94559-1-swboyd@chromium.org
* genirq, sched/isolation: Isolate from handling managed interruptsMing Lei2020-01-221-1/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The affinity of managed interrupts is completely handled in the kernel and cannot be changed via the /proc/irq/* interfaces from user space. As the kernel tries to spread out interrupts evenly accross CPUs on x86 to prevent vector exhaustion, it can happen that a managed interrupt whose affinity mask contains both isolated and housekeeping CPUs is routed to an isolated CPU. As a consequence IO submitted on a housekeeping CPU causes interrupts on the isolated CPU. Add a new sub-parameter 'managed_irq' for 'isolcpus' and the corresponding logic in the interrupt affinity selection code. The subparameter indicates to the interrupt affinity selection logic that it should try to avoid the above scenario. This isolation is best effort and only effective if the automatically assigned interrupt mask of a device queue contains isolated and housekeeping CPUs. If housekeeping CPUs are online then such interrupts are directed to the housekeeping CPU so that IO submitted on the housekeeping CPU cannot disturb the isolated CPU. If a queue's affinity mask contains only isolated CPUs then this parameter has no effect on the interrupt routing decision, though interrupts are only happening when tasks running on those isolated CPUs submit IO. IO submitted on housekeeping CPUs has no influence on those queues. If the affinity mask contains both housekeeping and isolated CPUs, but none of the contained housekeeping CPUs is online, then the interrupt is also routed to an isolated CPU. Interrupts are only delivered when one of the isolated CPUs in the affinity mask submits IO. If one of the contained housekeeping CPUs comes online, the CPU hotplug logic migrates the interrupt automatically back to the upcoming housekeeping CPU. Depending on the type of interrupt controller, this can require that at least one interrupt is delivered to the isolated CPU in order to complete the migration. [ tglx: Removed unused parameter, added and edited comments/documentation and rephrased the changelog so it contains more details. ] Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200120091625.17912-1-ming.lei@redhat.com
* genirq: Show irq name in non-oneshot error messageLuca Ceresoli2020-01-091-2/+2
| | | | | | | | | | | | | | Requesting a threaded IRQ with handler=NULL and !ONESHOT fails, but the error message does not include the IRQ line name, which makes it harder to find the offending driver. Print the IRQ line name to clarify where the error comes from. Use the same format as the other pr_err() above in the same function. Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191105140854.27893-1-luca@lucaceresoli.net
* Merge branch 'irq-core-for-linus' of ↵Linus Torvalds2019-09-171-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core irq updates from Thomas Gleixner: "Updates from the irq departement: - Update the interrupt spreading code so it handles numa node with different CPU counts properly. - A large overhaul of the ARM GiCv3 driver to support new PPI and SPI ranges. - Conversion of all alloc_fwnode() users to use physical addresses instead of virtual addresses so the virtual addresses are not leaked. The physical address is sufficient to identify the associated interrupt chip. - Add support for Marvel MMP3, Amlogic Meson SM1 interrupt chips. - Enforce interrupt threading at compile time if RT is enabled. - Small updates and improvements all over the place" * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) irqchip/gic-v3-its: Fix LPI release for Multi-MSI devices irqchip/uniphier-aidet: Use devm_platform_ioremap_resource() irqdomain: Add the missing assignment of domain->fwnode for named fwnode irqchip/mmp: Coexist with GIC root IRQ controller irqchip/mmp: Mask off interrupts from other cores irqchip/mmp: Add missing chained_irq_{enter,exit}() irqchip/mmp: Do not use of_address_to_resource() to get mux regs irqchip/meson-gpio: Add support for meson sm1 SoCs dt-bindings: interrupt-controller: New binding for the meson sm1 SoCs genirq/affinity: Remove const qualifier from node_to_cpumask argument genirq/affinity: Spread vectors on node according to nr_cpu ratio genirq/affinity: Improve __irq_build_affinity_masks() irqchip: Remove dev_err() usage after platform_get_irq() irqchip: Add include guard to irq-partition-percpu.h irqchip/mmp: Do not call irq_set_default_host() on DT platforms irqchip/gic-v3-its: Remove the redundant set_bit for lpi_map irqchip/gic-v3: Add quirks for HIP06/07 invalid GICD_TYPER erratum 161010803 irqchip/gic: Skip DT quirks when evaluating IIDR-based quirks irqchip/gic-v3: Warn about inconsistent implementations of extended ranges irqchip/gic-v3: Add EPPI range support ...
| * genirq: Force interrupt threading on RTThomas Gleixner2019-08-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | Switch force_irqthreads from a boot time modifiable variable to a compile time constant when CONFIG_PREEMPT_RT is enabled. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190816160923.12855-1-bigeasy@linutronix.de
* | sched/core: Convert get_task_struct() to return the taskMatthew Wilcox (Oracle)2019-07-251-2/+1
|/ | | | | | | | | | | | | Returning the pointer that was passed in allows us to write slightly more idiomatic code. Convert a few users. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190704221323.24290-1-willy@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'x86-apic-for-linus' of ↵Linus Torvalds2019-07-081-21/+69
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x96 apic updates from Thomas Gleixner: "Updates for the x86 APIC interrupt handling and APIC timer: - Fix a long standing issue with spurious interrupts which was caused by the big vector management rework a few years ago. Robert Hodaszi provided finally enough debug data and an excellent initial failure analysis which allowed to understand the underlying issues. This contains a change to the core interrupt management code which is required to handle this correctly for the APIC/IO_APIC. The core changes are NOOPs for most architectures except ARM64. ARM64 is not impacted by the change as confirmed by Marc Zyngier. - Newer systems allow to disable the PIT clock for power saving causing panic in the timer interrupt delivery check of the IO/APIC when the HPET timer is not enabled either. While the clock could be turned on this would cause an endless whack a mole game to chase the proper register in each affected chipset. These systems provide the relevant frequencies for TSC, CPU and the local APIC timer via CPUID and/or MSRs, which allows to avoid the PIT/HPET based calibration. As the calibration code is the only usage of the legacy timers on modern systems and is skipped anyway when the frequencies are known already, there is no point in setting up the PIT and actually checking for the interrupt delivery via IO/APIC. To achieve this on a wide variety of platforms, the CPUID/MSR based frequency readout has been made more robust, which also allowed to remove quite some workarounds which turned out to be not longer required. Thanks to Daniel Drake for analysis, patches and verification" * 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/irq: Seperate unused system vectors from spurious entry again x86/irq: Handle spurious interrupt after shutdown gracefully x86/ioapic: Implement irq_get_irqchip_state() callback genirq: Add optional hardware synchronization for shutdown genirq: Fix misleading synchronize_irq() documentation genirq: Delay deactivation in free_irq() x86/timer: Skip PIT initialization on modern chipsets x86/apic: Use non-atomic operations when possible x86/apic: Make apic_bsp_setup() static x86/tsc: Set LAPIC timer period to crystal clock frequency x86/apic: Rename 'lapic_timer_frequency' to 'lapic_timer_period' x86/tsc: Use CPUID.0x16 to calculate missing crystal frequency
| * genirq: Add optional hardware synchronization for shutdownThomas Gleixner2019-07-031-19/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | free_irq() ensures that no hardware interrupt handler is executing on a different CPU before actually releasing resources and deactivating the interrupt completely in a domain hierarchy. But that does not catch the case where the interrupt is on flight at the hardware level but not yet serviced by the target CPU. That creates an interesing race condition: CPU 0 CPU 1 IRQ CHIP interrupt is raised sent to CPU1 Unable to handle immediately (interrupts off, deep idle delay) mask() ... free() shutdown() synchronize_irq() release_resources() do_IRQ() -> resources are not available That might be harmless and just trigger a spurious interrupt warning, but some interrupt chips might get into a wedged state. Utilize the existing irq_get_irqchip_state() callback for the synchronization in free_irq(). synchronize_hardirq() is not using this mechanism as it might actually deadlock unter certain conditions, e.g. when called with interrupts disabled and the target CPU is the one on which the synchronization is invoked. synchronize_irq() uses it because that function cannot be called from non preemtible contexts as it might sleep. No functional change intended and according to Marc the existing GIC implementations where the driver supports the callback should be able to cope with that core change. Famous last words. Fixes: 464d12309e1b ("x86/vector: Switch IOAPIC to global reservation mode") Reported-by: Robert Hodaszi <Robert.Hodaszi@digi.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Link: https://lkml.kernel.org/r/20190628111440.279463375@linutronix.de
| * genirq: Fix misleading synchronize_irq() documentationThomas Gleixner2019-07-031-1/+2
| | | | | | | | | | | | | | | | | | | | The function might sleep, so it cannot be called from interrupt context. Not even with care. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Link: https://lkml.kernel.org/r/20190628111440.189241552@linutronix.de
| * genirq: Delay deactivation in free_irq()Thomas Gleixner2019-07-031-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When interrupts are shutdown, they are immediately deactivated in the irqdomain hierarchy. While this looks obviously correct there is a subtle issue: There might be an interrupt in flight when free_irq() is invoking the shutdown. This is properly handled at the irq descriptor / primary handler level, but the deactivation might completely disable resources which are required to acknowledge the interrupt. Split the shutdown code and deactivate the interrupt after synchronization in free_irq(). Fixup all other usage sites where this is not an issue to invoke the combined shutdown_and_deactivate() function instead. This still might be an issue if the interrupt in flight servicing is delayed on a remote CPU beyond the invocation of synchronize_irq(), but that cannot be handled at that level and needs to be handled in the synchronize_irq() context. Fixes: f8264e34965a ("irqdomain: Introduce new interfaces to support hierarchy irqdomains") Reported-by: Robert Hodaszi <Robert.Hodaszi@digi.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Link: https://lkml.kernel.org/r/20190628111440.098196390@linutronix.de
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