x86/mm/pat: Don't report PAT on CPUs that don't support it
[linux/fpc-iii.git] / drivers / firmware / psci_checker.c
blob6523ce9628659755fb6e6e0640e155cf02de31b2
1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
11 * Copyright (C) 2016 ARM Limited
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/atomic.h>
17 #include <linux/completion.h>
18 #include <linux/cpu.h>
19 #include <linux/cpuidle.h>
20 #include <linux/cpu_pm.h>
21 #include <linux/kernel.h>
22 #include <linux/kthread.h>
23 #include <uapi/linux/sched/types.h>
24 #include <linux/module.h>
25 #include <linux/preempt.h>
26 #include <linux/psci.h>
27 #include <linux/slab.h>
28 #include <linux/tick.h>
29 #include <linux/topology.h>
31 #include <asm/cpuidle.h>
33 #include <uapi/linux/psci.h>
35 #define NUM_SUSPEND_CYCLE (10)
37 static unsigned int nb_available_cpus;
38 static int tos_resident_cpu = -1;
40 static atomic_t nb_active_threads;
41 static struct completion suspend_threads_started =
42 COMPLETION_INITIALIZER(suspend_threads_started);
43 static struct completion suspend_threads_done =
44 COMPLETION_INITIALIZER(suspend_threads_done);
47 * We assume that PSCI operations are used if they are available. This is not
48 * necessarily true on arm64, since the decision is based on the
49 * "enable-method" property of each CPU in the DT, but given that there is no
50 * arch-specific way to check this, we assume that the DT is sensible.
52 static int psci_ops_check(void)
54 int migrate_type = -1;
55 int cpu;
57 if (!(psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend)) {
58 pr_warn("Missing PSCI operations, aborting tests\n");
59 return -EOPNOTSUPP;
62 if (psci_ops.migrate_info_type)
63 migrate_type = psci_ops.migrate_info_type();
65 if (migrate_type == PSCI_0_2_TOS_UP_MIGRATE ||
66 migrate_type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
67 /* There is a UP Trusted OS, find on which core it resides. */
68 for_each_online_cpu(cpu)
69 if (psci_tos_resident_on(cpu)) {
70 tos_resident_cpu = cpu;
71 break;
73 if (tos_resident_cpu == -1)
74 pr_warn("UP Trusted OS resides on no online CPU\n");
77 return 0;
80 static int find_clusters(const struct cpumask *cpus,
81 const struct cpumask **clusters)
83 unsigned int nb = 0;
84 cpumask_var_t tmp;
86 if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
87 return -ENOMEM;
88 cpumask_copy(tmp, cpus);
90 while (!cpumask_empty(tmp)) {
91 const struct cpumask *cluster =
92 topology_core_cpumask(cpumask_any(tmp));
94 clusters[nb++] = cluster;
95 cpumask_andnot(tmp, tmp, cluster);
98 free_cpumask_var(tmp);
99 return nb;
103 * offlined_cpus is a temporary array but passing it as an argument avoids
104 * multiple allocations.
106 static unsigned int down_and_up_cpus(const struct cpumask *cpus,
107 struct cpumask *offlined_cpus)
109 int cpu;
110 int err = 0;
112 cpumask_clear(offlined_cpus);
114 /* Try to power down all CPUs in the mask. */
115 for_each_cpu(cpu, cpus) {
116 int ret = cpu_down(cpu);
119 * cpu_down() checks the number of online CPUs before the TOS
120 * resident CPU.
122 if (cpumask_weight(offlined_cpus) + 1 == nb_available_cpus) {
123 if (ret != -EBUSY) {
124 pr_err("Unexpected return code %d while trying "
125 "to power down last online CPU %d\n",
126 ret, cpu);
127 ++err;
129 } else if (cpu == tos_resident_cpu) {
130 if (ret != -EPERM) {
131 pr_err("Unexpected return code %d while trying "
132 "to power down TOS resident CPU %d\n",
133 ret, cpu);
134 ++err;
136 } else if (ret != 0) {
137 pr_err("Error occurred (%d) while trying "
138 "to power down CPU %d\n", ret, cpu);
139 ++err;
142 if (ret == 0)
143 cpumask_set_cpu(cpu, offlined_cpus);
146 /* Try to power up all the CPUs that have been offlined. */
147 for_each_cpu(cpu, offlined_cpus) {
148 int ret = cpu_up(cpu);
150 if (ret != 0) {
151 pr_err("Error occurred (%d) while trying "
152 "to power up CPU %d\n", ret, cpu);
153 ++err;
154 } else {
155 cpumask_clear_cpu(cpu, offlined_cpus);
160 * Something went bad at some point and some CPUs could not be turned
161 * back on.
163 WARN_ON(!cpumask_empty(offlined_cpus) ||
164 num_online_cpus() != nb_available_cpus);
166 return err;
169 static int hotplug_tests(void)
171 int err;
172 cpumask_var_t offlined_cpus;
173 int i, nb_cluster;
174 const struct cpumask **clusters;
175 char *page_buf;
177 err = -ENOMEM;
178 if (!alloc_cpumask_var(&offlined_cpus, GFP_KERNEL))
179 return err;
180 /* We may have up to nb_available_cpus clusters. */
181 clusters = kmalloc_array(nb_available_cpus, sizeof(*clusters),
182 GFP_KERNEL);
183 if (!clusters)
184 goto out_free_cpus;
185 page_buf = (char *)__get_free_page(GFP_KERNEL);
186 if (!page_buf)
187 goto out_free_clusters;
189 err = 0;
190 nb_cluster = find_clusters(cpu_online_mask, clusters);
193 * Of course the last CPU cannot be powered down and cpu_down() should
194 * refuse doing that.
196 pr_info("Trying to turn off and on again all CPUs\n");
197 err += down_and_up_cpus(cpu_online_mask, offlined_cpus);
200 * Take down CPUs by cluster this time. When the last CPU is turned
201 * off, the cluster itself should shut down.
203 for (i = 0; i < nb_cluster; ++i) {
204 int cluster_id =
205 topology_physical_package_id(cpumask_any(clusters[i]));
206 ssize_t len = cpumap_print_to_pagebuf(true, page_buf,
207 clusters[i]);
208 /* Remove trailing newline. */
209 page_buf[len - 1] = '\0';
210 pr_info("Trying to turn off and on again cluster %d "
211 "(CPUs %s)\n", cluster_id, page_buf);
212 err += down_and_up_cpus(clusters[i], offlined_cpus);
215 free_page((unsigned long)page_buf);
216 out_free_clusters:
217 kfree(clusters);
218 out_free_cpus:
219 free_cpumask_var(offlined_cpus);
220 return err;
223 static void dummy_callback(unsigned long ignored) {}
225 static int suspend_cpu(int index, bool broadcast)
227 int ret;
229 arch_cpu_idle_enter();
231 if (broadcast) {
233 * The local timer will be shut down, we need to enter tick
234 * broadcast.
236 ret = tick_broadcast_enter();
237 if (ret) {
239 * In the absence of hardware broadcast mechanism,
240 * this CPU might be used to broadcast wakeups, which
241 * may be why entering tick broadcast has failed.
242 * There is little the kernel can do to work around
243 * that, so enter WFI instead (idle state 0).
245 cpu_do_idle();
246 ret = 0;
247 goto out_arch_exit;
252 * Replicate the common ARM cpuidle enter function
253 * (arm_enter_idle_state).
255 ret = CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, index);
257 if (broadcast)
258 tick_broadcast_exit();
260 out_arch_exit:
261 arch_cpu_idle_exit();
263 return ret;
266 static int suspend_test_thread(void *arg)
268 int cpu = (long)arg;
269 int i, nb_suspend = 0, nb_shallow_sleep = 0, nb_err = 0;
270 struct sched_param sched_priority = { .sched_priority = MAX_RT_PRIO-1 };
271 struct cpuidle_device *dev;
272 struct cpuidle_driver *drv;
273 /* No need for an actual callback, we just want to wake up the CPU. */
274 struct timer_list wakeup_timer;
276 /* Wait for the main thread to give the start signal. */
277 wait_for_completion(&suspend_threads_started);
279 /* Set maximum priority to preempt all other threads on this CPU. */
280 if (sched_setscheduler_nocheck(current, SCHED_FIFO, &sched_priority))
281 pr_warn("Failed to set suspend thread scheduler on CPU %d\n",
282 cpu);
284 dev = this_cpu_read(cpuidle_devices);
285 drv = cpuidle_get_cpu_driver(dev);
287 pr_info("CPU %d entering suspend cycles, states 1 through %d\n",
288 cpu, drv->state_count - 1);
290 setup_timer_on_stack(&wakeup_timer, dummy_callback, 0);
291 for (i = 0; i < NUM_SUSPEND_CYCLE; ++i) {
292 int index;
294 * Test all possible states, except 0 (which is usually WFI and
295 * doesn't use PSCI).
297 for (index = 1; index < drv->state_count; ++index) {
298 struct cpuidle_state *state = &drv->states[index];
299 bool broadcast = state->flags & CPUIDLE_FLAG_TIMER_STOP;
300 int ret;
303 * Set the timer to wake this CPU up in some time (which
304 * should be largely sufficient for entering suspend).
305 * If the local tick is disabled when entering suspend,
306 * suspend_cpu() takes care of switching to a broadcast
307 * tick, so the timer will still wake us up.
309 mod_timer(&wakeup_timer, jiffies +
310 usecs_to_jiffies(state->target_residency));
312 /* IRQs must be disabled during suspend operations. */
313 local_irq_disable();
315 ret = suspend_cpu(index, broadcast);
318 * We have woken up. Re-enable IRQs to handle any
319 * pending interrupt, do not wait until the end of the
320 * loop.
322 local_irq_enable();
324 if (ret == index) {
325 ++nb_suspend;
326 } else if (ret >= 0) {
327 /* We did not enter the expected state. */
328 ++nb_shallow_sleep;
329 } else {
330 pr_err("Failed to suspend CPU %d: error %d "
331 "(requested state %d, cycle %d)\n",
332 cpu, ret, index, i);
333 ++nb_err;
339 * Disable the timer to make sure that the timer will not trigger
340 * later.
342 del_timer(&wakeup_timer);
344 if (atomic_dec_return_relaxed(&nb_active_threads) == 0)
345 complete(&suspend_threads_done);
347 /* Give up on RT scheduling and wait for termination. */
348 sched_priority.sched_priority = 0;
349 if (sched_setscheduler_nocheck(current, SCHED_NORMAL, &sched_priority))
350 pr_warn("Failed to set suspend thread scheduler on CPU %d\n",
351 cpu);
352 for (;;) {
353 /* Needs to be set first to avoid missing a wakeup. */
354 set_current_state(TASK_INTERRUPTIBLE);
355 if (kthread_should_stop()) {
356 __set_current_state(TASK_RUNNING);
357 break;
359 schedule();
362 pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n",
363 cpu, nb_suspend, nb_shallow_sleep, nb_err);
365 return nb_err;
368 static int suspend_tests(void)
370 int i, cpu, err = 0;
371 struct task_struct **threads;
372 int nb_threads = 0;
374 threads = kmalloc_array(nb_available_cpus, sizeof(*threads),
375 GFP_KERNEL);
376 if (!threads)
377 return -ENOMEM;
380 * Stop cpuidle to prevent the idle tasks from entering a deep sleep
381 * mode, as it might interfere with the suspend threads on other CPUs.
382 * This does not prevent the suspend threads from using cpuidle (only
383 * the idle tasks check this status). Take the idle lock so that
384 * the cpuidle driver and device look-up can be carried out safely.
386 cpuidle_pause_and_lock();
388 for_each_online_cpu(cpu) {
389 struct task_struct *thread;
390 /* Check that cpuidle is available on that CPU. */
391 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
392 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
394 if (!dev || !drv) {
395 pr_warn("cpuidle not available on CPU %d, ignoring\n",
396 cpu);
397 continue;
400 thread = kthread_create_on_cpu(suspend_test_thread,
401 (void *)(long)cpu, cpu,
402 "psci_suspend_test");
403 if (IS_ERR(thread))
404 pr_err("Failed to create kthread on CPU %d\n", cpu);
405 else
406 threads[nb_threads++] = thread;
409 if (nb_threads < 1) {
410 err = -ENODEV;
411 goto out;
414 atomic_set(&nb_active_threads, nb_threads);
417 * Wake up the suspend threads. To avoid the main thread being preempted
418 * before all the threads have been unparked, the suspend threads will
419 * wait for the completion of suspend_threads_started.
421 for (i = 0; i < nb_threads; ++i)
422 wake_up_process(threads[i]);
423 complete_all(&suspend_threads_started);
425 wait_for_completion(&suspend_threads_done);
428 /* Stop and destroy all threads, get return status. */
429 for (i = 0; i < nb_threads; ++i)
430 err += kthread_stop(threads[i]);
431 out:
432 cpuidle_resume_and_unlock();
433 kfree(threads);
434 return err;
437 static int __init psci_checker(void)
439 int ret;
442 * Since we're in an initcall, we assume that all the CPUs that all
443 * CPUs that can be onlined have been onlined.
445 * The tests assume that hotplug is enabled but nobody else is using it,
446 * otherwise the results will be unpredictable. However, since there
447 * is no userspace yet in initcalls, that should be fine, as long as
448 * no torture test is running at the same time (see Kconfig).
450 nb_available_cpus = num_online_cpus();
452 /* Check PSCI operations are set up and working. */
453 ret = psci_ops_check();
454 if (ret)
455 return ret;
457 pr_info("PSCI checker started using %u CPUs\n", nb_available_cpus);
459 pr_info("Starting hotplug tests\n");
460 ret = hotplug_tests();
461 if (ret == 0)
462 pr_info("Hotplug tests passed OK\n");
463 else if (ret > 0)
464 pr_err("%d error(s) encountered in hotplug tests\n", ret);
465 else {
466 pr_err("Out of memory\n");
467 return ret;
470 pr_info("Starting suspend tests (%d cycles per state)\n",
471 NUM_SUSPEND_CYCLE);
472 ret = suspend_tests();
473 if (ret == 0)
474 pr_info("Suspend tests passed OK\n");
475 else if (ret > 0)
476 pr_err("%d error(s) encountered in suspend tests\n", ret);
477 else {
478 switch (ret) {
479 case -ENOMEM:
480 pr_err("Out of memory\n");
481 break;
482 case -ENODEV:
483 pr_warn("Could not start suspend tests on any CPU\n");
484 break;
488 pr_info("PSCI checker completed\n");
489 return ret < 0 ? ret : 0;
491 late_initcall(psci_checker);