diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2022-05-06 15:54:01 -0700 |
|---|---|---|
| committer | Hans de Goede <hdegoede@redhat.com> | 2022-05-12 15:35:29 +0200 |
| commit | 2760f5a415c3b86c6394738c6cff740c8b4ce664 (patch) | |
| tree | 97c1c0391a33742be5c5ef7b7b0dd0b990bf4f97 | |
| parent | db1af12929c99d15fc04cc5c4447b87ab51eab0a (diff) | |
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 <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220506225410.1652287-4-tony.luck@intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
| -rw-r--r-- | include/linux/stop_machine.h | 16 | ||||
| -rw-r--r-- | kernel/stop_machine.c | 21 |
2 files changed, 37 insertions, 0 deletions
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 */ diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index cbc30271ea4d..0887b3af609e 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -633,6 +633,27 @@ int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus) } EXPORT_SYMBOL_GPL(stop_machine); +#ifdef CONFIG_SCHED_SMT +int stop_core_cpuslocked(unsigned int cpu, cpu_stop_fn_t fn, void *data) +{ + const struct cpumask *smt_mask = cpu_smt_mask(cpu); + + struct multi_stop_data msdata = { + .fn = fn, + .data = data, + .num_threads = cpumask_weight(smt_mask), + .active_cpus = smt_mask, + }; + + lockdep_assert_cpus_held(); + + /* Set the initial state and stop all online cpus. */ + set_state(&msdata, MULTI_STOP_PREPARE); + return stop_cpus(smt_mask, multi_cpu_stop, &msdata); +} +EXPORT_SYMBOL_GPL(stop_core_cpuslocked); +#endif + /** * stop_machine_from_inactive_cpu - stop_machine() from inactive CPU * @fn: the function to run |