From 2760f5a415c3b86c6394738c6cff740c8b4ce664 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 6 May 2022 15:54:01 -0700 Subject: stop_machine: Add stop_core_cpuslocked() for per-core operations Hardware core level testing features require near simultaneous execution of WRMSR instructions on all threads of a core to initiate a test. Provide a customized cut down version of stop_machine_cpuslocked() that just operates on the threads of a single core. Suggested-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Tony Luck Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/20220506225410.1652287-4-tony.luck@intel.com Signed-off-by: Hans de Goede --- include/linux/stop_machine.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux') diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h index 46fb3ebdd16e..ea7a74ea7389 100644 --- a/include/linux/stop_machine.h +++ b/include/linux/stop_machine.h @@ -124,6 +124,22 @@ int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); */ int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); +/** + * stop_core_cpuslocked: - stop all threads on just one core + * @cpu: any cpu in the targeted core + * @fn: the function to run + * @data: the data ptr for @fn() + * + * Same as above, but instead of every CPU, only the logical CPUs of a + * single core are affected. + * + * Context: Must be called from within a cpus_read_lock() protected region. + * + * Return: 0 if all executions of @fn returned 0, any non zero return + * value if any returned non zero. + */ +int stop_core_cpuslocked(unsigned int cpu, cpu_stop_fn_t fn, void *data); + int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); #else /* CONFIG_SMP || CONFIG_HOTPLUG_CPU */ -- cgit v1.2.3