From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- drivers/clocksource/dummy_timer.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 drivers/clocksource/dummy_timer.c (limited to 'drivers/clocksource/dummy_timer.c') diff --git a/drivers/clocksource/dummy_timer.c b/drivers/clocksource/dummy_timer.c new file mode 100644 index 000000000..6cee6dce5 --- /dev/null +++ b/drivers/clocksource/dummy_timer.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/drivers/clocksource/dummy_timer.c + * + * Copyright (C) 2013 ARM Ltd. + * All Rights Reserved + */ +#include +#include +#include +#include +#include + +static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt); + +static int dummy_timer_starting_cpu(unsigned int cpu) +{ + struct clock_event_device *evt = per_cpu_ptr(&dummy_timer_evt, cpu); + + evt->name = "dummy_timer"; + evt->features = CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_DUMMY; + evt->rating = 100; + evt->cpumask = cpumask_of(cpu); + + clockevents_register_device(evt); + return 0; +} + +static int __init dummy_timer_register(void) +{ + return cpuhp_setup_state(CPUHP_AP_DUMMY_TIMER_STARTING, + "clockevents/dummy_timer:starting", + dummy_timer_starting_cpu, NULL); +} +early_initcall(dummy_timer_register); -- cgit v1.3.1