linux-toradex.git/kernel/irq, branch v6.18-rc2

Merge tag 'irq-core-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-09-30T22:55:25+00:00

Pull irq core updates from Thomas Gleixner:
 "A set of updates for the interrupt core subsystem:

   - Introduce irq_chip_[startup|shutdown]_parent() to prepare for
     addressing a few short comings in the PCI/MSI interrupt subsystem.

     It allows to utilize the interrupt chip startup/shutdown callbacks
     for initializing the interrupt chip hierarchy properly on certain
     RISCV implementations and provides a mechanism to reduce the
     overhead of masking and unmasking PCI/MSI interrupts during
     operation when the underlying MSI provider can mask the interrupt.

     The actual usage comes with the interrupt driver pull request.

   - Add generic error handling for devm_request_*_irq()

     This allows to remove the zoo of random error printk's all over the
     usage sites.

   - Add a mechanism to warn about long-running interrupt handlers

     Long running interrupt handlers can introduce latencies and
     tracking them down is a tedious task. The tracking has to be
     enabled with a threshold on the kernel command line and utilizes a
     static branch to remove the overhead when disabled.

   - Update and extend the selftests which validate the CPU hotplug
     interrupt migration logic

   - Allow dropping the per CPU softirq lock on PREEMPT_RT kernels,
     which causes contention and latencies all over the place.

     The serialization requirements have been pushed down into the
     actual affected usage sites already.

   - The usual small cleanups and improvements"

* tag 'irq-core-2025-09-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  softirq: Allow to drop the softirq-BKL lock on PREEMPT_RT
  softirq: Provide a handshake for canceling tasklets via polling
  genirq/test: Ensure CPU 1 is online for hotplug test
  genirq/test: Drop CONFIG_GENERIC_IRQ_MIGRATION assumptions
  genirq/test: Depend on SPARSE_IRQ
  genirq/test: Fail early if interrupt request fails
  genirq/test: Factor out fake-virq setup
  genirq/test: Select IRQ_DOMAIN
  genirq/test: Fix depth tests on architectures with NOREQUEST by default.
  genirq: Add support for warning on long-running interrupt handlers
  genirq/devres: Add error handling in devm_request_*_irq()
  genirq: Add irq_chip_(startup/shutdown)_parent()
  genirq: Remove GENERIC_IRQ_LEGACY

genirq/msi: Remove msi_post_free()

2025-09-23T08:59:51+00:00

The only user of msi_post_free() - powerpc/pseries - has been changed to
use msi_teardown().

Remove this unused callback.

Signed-off-by: Nam Cao 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Madhavan Srinivasan 
Link: https://patch.msgid.link/20250916061007.964005-1-namcao@linutronix.de

genirq/test: Ensure CPU 1 is online for hotplug test

2025-09-03T15:04:52+00:00

It's possible to run these tests on platforms that think they have a
hotpluggable CPU1, but for whatever reason, CPU1 is not online and can't be
brought online:

    # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:210
    Expected remove_cpu(1) == 0, but
        remove_cpu(1) == 1 (0x1)
CPU1: failed to boot: -38
    # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:214
    Expected add_cpu(1) == 0, but
        add_cpu(1) == -38 (0xffffffffffffffda)

Check that CPU1 is actually online before trying to run the test.

Fixes: 66067c3c8a1e ("genirq: Add kunit tests for depth counts")
Reported-by: Guenter Roeck 
Signed-off-by: Brian Norris 
Signed-off-by: Thomas Gleixner 
Tested-by: Guenter Roeck 
Reviewed-by: David Gow 
Link: https://lore.kernel.org/all/20250822190140.2154646-7-briannorris@chromium.org

genirq/test: Drop CONFIG_GENERIC_IRQ_MIGRATION assumptions

2025-09-03T15:04:52+00:00

Not all platforms use the generic IRQ migration code, even if they select
GENERIC_IRQ_MIGRATION. (See, for example, powerpc / pseries_cpu_disable().)

If such platforms don't perform managed shutdown the same way, the interrupt
may not actually shut down, and these tests fail:

[    4.357022][  T101]     # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:211
[    4.357022][  T101]     Expected irqd_is_activated(data) to be false, but is true
[    4.358128][  T101]     # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:212
[    4.358128][  T101]     Expected irqd_is_started(data) to be false, but is true
[    4.375558][  T101]     # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:216
[    4.375558][  T101]     Expected irqd_is_activated(data) to be false, but is true
[    4.376088][  T101]     # irq_cpuhotplug_test: EXPECTATION FAILED at kernel/irq/irq_test.c:217
[    4.376088][  T101]     Expected irqd_is_started(data) to be false, but is true
[    4.377851][    T1]     # irq_cpuhotplug_test: pass:0 fail:1 skip:0 total:1
[    4.377901][    T1]     not ok 4 irq_cpuhotplug_test
[    4.378073][    T1] # irq_test_cases: pass:3 fail:1 skip:0 total:4

Rather than test that PowerPC performs migration the same way as the
unterrupt core, just drop the state checks. The point of the test was to
ensure that the code kept |depth| balanced, which still can be tested for.

Fixes: 66067c3c8a1e ("genirq: Add kunit tests for depth counts")
Reported-by: Guenter Roeck 
Signed-off-by: Brian Norris 
Signed-off-by: Thomas Gleixner 
Tested-by: Guenter Roeck 
Reviewed-by: David Gow 
Link: https://lore.kernel.org/all/20250822190140.2154646-6-briannorris@chromium.org

genirq/test: Depend on SPARSE_IRQ

2025-09-03T15:04:52+00:00

Some architectures have a static interrupt layout, with a limited number of
interrupts. Without SPARSE_IRQ, the test may not be able to allocate any
fake interrupts, and the test will fail. (This occurs on ARCH=m68k, for
example.)

Additionally, managed-affinity is only supported with CONFIG_SPARSE_IRQ=y,
so irq_shutdown_depth_test() and irq_cpuhotplug_test() would fail without
it.

Add a 'SPARSE_IRQ' dependency to avoid these problems.

Many architectures 'select SPARSE_IRQ', so this is easy to miss.

Notably, this also excludes ARCH=um from running any of these tests, even
though some of them might work.

Fixes: 66067c3c8a1e ("genirq: Add kunit tests for depth counts")
Reported-by: Guenter Roeck 
Signed-off-by: Brian Norris 
Signed-off-by: Thomas Gleixner 
Tested-by: Guenter Roeck 
Reviewed-by: David Gow 
Link: https://lore.kernel.org/all/20250822190140.2154646-5-briannorris@chromium.org

genirq/test: Fail early if interrupt request fails

2025-09-03T15:04:52+00:00

Requesting an interrupt is part of the basic test setup. If it fails, most
of the subsequent tests are likely to fail, and the output gets noisy.

Use "assert" to fail early.

Signed-off-by: Brian Norris 
Signed-off-by: Thomas Gleixner 
Tested-by: Guenter Roeck 
Reviewed-by: David Gow 
Link: https://lore.kernel.org/all/20250822190140.2154646-4-briannorris@chromium.org

genirq/test: Factor out fake-virq setup

2025-09-03T15:04:52+00:00

A few things need to be repeated in tests. Factor out the creation of fake
interrupts.

Signed-off-by: Brian Norris 
Signed-off-by: Thomas Gleixner 
Tested-by: Guenter Roeck 
Reviewed-by: David Gow 
Link: https://lore.kernel.org/all/20250822190140.2154646-3-briannorris@chromium.org

genirq/test: Select IRQ_DOMAIN

2025-09-03T15:04:52+00:00

These tests use irq_domain_alloc_descs() and so require CONFIG_IRQ_DOMAIN.

Fixes: 66067c3c8a1e ("genirq: Add kunit tests for depth counts")
Reported-by: Guenter Roeck 
Signed-off-by: Brian Norris 
Signed-off-by: Thomas Gleixner 
Tested-by: Guenter Roeck 
Reviewed-by: David Gow 
Link: https://lore.kernel.org/all/20250822190140.2154646-2-briannorris@chromium.org
Closes: https://lore.kernel.org/lkml/ded44edf-eeb7-420c-b8a8-d6543b955e6e@roeck-us.net/

genirq/test: Fix depth tests on architectures with NOREQUEST by default.

2025-09-03T15:04:51+00:00

The new irq KUnit tests fail on some architectures (notably PowerPC and
32-bit ARM), as the request_irq() call fails due to the ARCH_IRQ_INIT_FLAGS
containing IRQ_NOREQUEST, yielding the following errors:

[10:17:45]     # irq_free_disabled_test: EXPECTATION FAILED at kernel/irq/irq_test.c:88
[10:17:45]     Expected ret == 0, but
[10:17:45]         ret == -22 (0xffffffffffffffea)
[10:17:45]     # irq_free_disabled_test: EXPECTATION FAILED at kernel/irq/irq_test.c:90
[10:17:45]     Expected desc->depth == 0, but
[10:17:45]         desc->depth == 1 (0x1)
[10:17:45]     # irq_free_disabled_test: EXPECTATION FAILED at kernel/irq/irq_test.c:93
[10:17:45]     Expected desc->depth == 1, but
[10:17:45]         desc->depth == 2 (0x2)

By clearing IRQ_NOREQUEST from the interrupt descriptor, these tests now
pass on ARM and PowerPC.

Fixes: 66067c3c8a1e ("genirq: Add kunit tests for depth counts")
Signed-off-by: David Gow 
Signed-off-by: Thomas Gleixner 
Tested-by: Guenter Roeck 
Tested-by: Brian Norris 
Reviewed-by: Brian Norris 
Link: https://lore.kernel.org/all/20250816094528.3560222-2-davidgow@google.com

genirq: Add support for warning on long-running interrupt handlers

2025-09-03T14:10:40+00:00

Introduce a mechanism to detect and warn about prolonged interrupt handlers.
With a new command-line parameter (irqhandler.duration_warn_us=), users can
configure the duration threshold in microseconds when a warning in such
format should be emitted:

"[CPU14] long duration of IRQ[159:bad_irq_handler [long_irq]], took: 1330 us"

The implementation uses local_clock() to measure the execution duration of the
generic IRQ per-CPU event handler.

Signed-off-by: Wladislav Wiebe 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/all/20250804093525.851-1-wladislav.wiebe@nokia.com