From 35fae10aaf080c2de06a80463e1129e588600db8 Mon Sep 17 00:00:00 2001 From: Sinan Nalkaya Date: Wed, 27 Aug 2025 15:04:18 -0700 Subject: [PATCH] um: Support SPARSE_IRQ Motivation: IRQ KUnit tests are going to require CONFIG_SPARSE_IRQ [1] in order to: (a) reliably allocate additional (fake) IRQs and (b) ensure we can test managed affinity, which is only supported with SPARSE_IRQ. It seems that the only thing necessary for ARCH=um is to tell the genirq core to skip over our preallocated NR_IRQS. Tested with: $ ./tools/testing/kunit/kunit.py run [...] [13:55:58] Testing complete. Ran 676 tests: passed: 646, skipped: 30 [...] This compares with pre-patch results: Ran 672 tests: passed: 644, skipped: 28 i.e., we no longer skip tests that 'depend on SPARSE_IRQ', and existing tests all pass. [1] [PATCH v2 4/6] genirq/test: Depend on SPARSE_IRQ https://lore.kernel.org/all/CABVgOSngoD0fh1WEkUCEwSdk0Joypo3dA_Y_SjW+K=nVDnZs3Q@mail.gmail.com/ Signed-off-by: Sinan Nalkaya [Brian: Adapted Sinan's patch; rewrote commit message] Signed-off-by: Brian Norris Tested-by: David Gow Signed-off-by: Johannes Berg --- arch/um/Kconfig | 1 + arch/um/kernel/irq.c | 5 +++++ 2 files changed, 6 insertions(+) diff --git a/arch/um/Kconfig b/arch/um/Kconfig index 9083bfdb77350..8161cc5ae6f7e 100644 --- a/arch/um/Kconfig +++ b/arch/um/Kconfig @@ -38,6 +38,7 @@ config UML select HAVE_ARCH_TRACEHOOK select HAVE_SYSCALL_TRACEPOINTS select THREAD_INFO_IN_TASK + select SPARSE_IRQ config MMU bool diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c index 0dfaf96bb7da3..d69d137a0334a 100644 --- a/arch/um/kernel/irq.c +++ b/arch/um/kernel/irq.c @@ -691,6 +691,11 @@ void __init init_IRQ(void) os_setup_epoll(); } +int __init arch_probe_nr_irqs(void) +{ + return NR_IRQS; +} + void sigchld_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs, void *mc) { -- 2.47.3