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1// SPDX-License-Identifier: GPL-2.0-only2/*3 *4 * Copyright (C) 2016 ARM Limited5 */6 7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt8 9#include <linux/atomic.h>10#include <linux/completion.h>11#include <linux/cpu.h>12#include <linux/cpuidle.h>13#include <linux/cpu_pm.h>14#include <linux/kernel.h>15#include <linux/kthread.h>16#include <uapi/linux/sched/types.h>17#include <linux/module.h>18#include <linux/preempt.h>19#include <linux/psci.h>20#include <linux/slab.h>21#include <linux/tick.h>22#include <linux/topology.h>23 24#include <asm/cpuidle.h>25 26#include <uapi/linux/psci.h>27 28#define NUM_SUSPEND_CYCLE (10)29 30static unsigned int nb_available_cpus;31static int tos_resident_cpu = -1;32 33static atomic_t nb_active_threads;34static struct completion suspend_threads_started =35 COMPLETION_INITIALIZER(suspend_threads_started);36static struct completion suspend_threads_done =37 COMPLETION_INITIALIZER(suspend_threads_done);38 39/*40 * We assume that PSCI operations are used if they are available. This is not41 * necessarily true on arm64, since the decision is based on the42 * "enable-method" property of each CPU in the DT, but given that there is no43 * arch-specific way to check this, we assume that the DT is sensible.44 */45static int psci_ops_check(void)46{47 int migrate_type = -1;48 int cpu;49 50 if (!(psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend)) {51 pr_warn("Missing PSCI operations, aborting tests\n");52 return -EOPNOTSUPP;53 }54 55 if (psci_ops.migrate_info_type)56 migrate_type = psci_ops.migrate_info_type();57 58 if (migrate_type == PSCI_0_2_TOS_UP_MIGRATE ||59 migrate_type == PSCI_0_2_TOS_UP_NO_MIGRATE) {60 /* There is a UP Trusted OS, find on which core it resides. */61 for_each_online_cpu(cpu)62 if (psci_tos_resident_on(cpu)) {63 tos_resident_cpu = cpu;64 break;65 }66 if (tos_resident_cpu == -1)67 pr_warn("UP Trusted OS resides on no online CPU\n");68 }69 70 return 0;71}72 73/*74 * offlined_cpus is a temporary array but passing it as an argument avoids75 * multiple allocations.76 */77static unsigned int down_and_up_cpus(const struct cpumask *cpus,78 struct cpumask *offlined_cpus)79{80 int cpu;81 int err = 0;82 83 cpumask_clear(offlined_cpus);84 85 /* Try to power down all CPUs in the mask. */86 for_each_cpu(cpu, cpus) {87 int ret = remove_cpu(cpu);88 89 /*90 * cpu_down() checks the number of online CPUs before the TOS91 * resident CPU.92 */93 if (cpumask_weight(offlined_cpus) + 1 == nb_available_cpus) {94 if (ret != -EBUSY) {95 pr_err("Unexpected return code %d while trying "96 "to power down last online CPU %d\n",97 ret, cpu);98 ++err;99 }100 } else if (cpu == tos_resident_cpu) {101 if (ret != -EPERM) {102 pr_err("Unexpected return code %d while trying "103 "to power down TOS resident CPU %d\n",104 ret, cpu);105 ++err;106 }107 } else if (ret != 0) {108 pr_err("Error occurred (%d) while trying "109 "to power down CPU %d\n", ret, cpu);110 ++err;111 }112 113 if (ret == 0)114 cpumask_set_cpu(cpu, offlined_cpus);115 }116 117 /* Try to power up all the CPUs that have been offlined. */118 for_each_cpu(cpu, offlined_cpus) {119 int ret = add_cpu(cpu);120 121 if (ret != 0) {122 pr_err("Error occurred (%d) while trying "123 "to power up CPU %d\n", ret, cpu);124 ++err;125 } else {126 cpumask_clear_cpu(cpu, offlined_cpus);127 }128 }129 130 /*131 * Something went bad at some point and some CPUs could not be turned132 * back on.133 */134 WARN_ON(!cpumask_empty(offlined_cpus) ||135 num_online_cpus() != nb_available_cpus);136 137 return err;138}139 140static void free_cpu_groups(int num, cpumask_var_t **pcpu_groups)141{142 int i;143 cpumask_var_t *cpu_groups = *pcpu_groups;144 145 for (i = 0; i < num; ++i)146 free_cpumask_var(cpu_groups[i]);147 kfree(cpu_groups);148}149 150static int alloc_init_cpu_groups(cpumask_var_t **pcpu_groups)151{152 int num_groups = 0;153 cpumask_var_t tmp, *cpu_groups;154 155 if (!alloc_cpumask_var(&tmp, GFP_KERNEL))156 return -ENOMEM;157 158 cpu_groups = kcalloc(nb_available_cpus, sizeof(*cpu_groups),159 GFP_KERNEL);160 if (!cpu_groups) {161 free_cpumask_var(tmp);162 return -ENOMEM;163 }164 165 cpumask_copy(tmp, cpu_online_mask);166 167 while (!cpumask_empty(tmp)) {168 const struct cpumask *cpu_group =169 topology_core_cpumask(cpumask_any(tmp));170 171 if (!alloc_cpumask_var(&cpu_groups[num_groups], GFP_KERNEL)) {172 free_cpumask_var(tmp);173 free_cpu_groups(num_groups, &cpu_groups);174 return -ENOMEM;175 }176 cpumask_copy(cpu_groups[num_groups++], cpu_group);177 cpumask_andnot(tmp, tmp, cpu_group);178 }179 180 free_cpumask_var(tmp);181 *pcpu_groups = cpu_groups;182 183 return num_groups;184}185 186static int hotplug_tests(void)187{188 int i, nb_cpu_group, err = -ENOMEM;189 cpumask_var_t offlined_cpus, *cpu_groups;190 char *page_buf;191 192 if (!alloc_cpumask_var(&offlined_cpus, GFP_KERNEL))193 return err;194 195 nb_cpu_group = alloc_init_cpu_groups(&cpu_groups);196 if (nb_cpu_group < 0)197 goto out_free_cpus;198 page_buf = (char *)__get_free_page(GFP_KERNEL);199 if (!page_buf)200 goto out_free_cpu_groups;201 202 /*203 * Of course the last CPU cannot be powered down and cpu_down() should204 * refuse doing that.205 */206 pr_info("Trying to turn off and on again all CPUs\n");207 err = down_and_up_cpus(cpu_online_mask, offlined_cpus);208 209 /*210 * Take down CPUs by cpu group this time. When the last CPU is turned211 * off, the cpu group itself should shut down.212 */213 for (i = 0; i < nb_cpu_group; ++i) {214 ssize_t len = cpumap_print_to_pagebuf(true, page_buf,215 cpu_groups[i]);216 /* Remove trailing newline. */217 page_buf[len - 1] = '\0';218 pr_info("Trying to turn off and on again group %d (CPUs %s)\n",219 i, page_buf);220 err += down_and_up_cpus(cpu_groups[i], offlined_cpus);221 }222 223 free_page((unsigned long)page_buf);224out_free_cpu_groups:225 free_cpu_groups(nb_cpu_group, &cpu_groups);226out_free_cpus:227 free_cpumask_var(offlined_cpus);228 return err;229}230 231static void dummy_callback(struct timer_list *unused) {}232 233static int suspend_cpu(struct cpuidle_device *dev,234 struct cpuidle_driver *drv, int index)235{236 struct cpuidle_state *state = &drv->states[index];237 bool broadcast = state->flags & CPUIDLE_FLAG_TIMER_STOP;238 int ret;239 240 arch_cpu_idle_enter();241 242 if (broadcast) {243 /*244 * The local timer will be shut down, we need to enter tick245 * broadcast.246 */247 ret = tick_broadcast_enter();248 if (ret) {249 /*250 * In the absence of hardware broadcast mechanism,251 * this CPU might be used to broadcast wakeups, which252 * may be why entering tick broadcast has failed.253 * There is little the kernel can do to work around254 * that, so enter WFI instead (idle state 0).255 */256 cpu_do_idle();257 ret = 0;258 goto out_arch_exit;259 }260 }261 262 ret = state->enter(dev, drv, index);263 264 if (broadcast)265 tick_broadcast_exit();266 267out_arch_exit:268 arch_cpu_idle_exit();269 270 return ret;271}272 273static int suspend_test_thread(void *arg)274{275 int cpu = (long)arg;276 int i, nb_suspend = 0, nb_shallow_sleep = 0, nb_err = 0;277 struct cpuidle_device *dev;278 struct cpuidle_driver *drv;279 /* No need for an actual callback, we just want to wake up the CPU. */280 struct timer_list wakeup_timer;281 282 /* Wait for the main thread to give the start signal. */283 wait_for_completion(&suspend_threads_started);284 285 /* Set maximum priority to preempt all other threads on this CPU. */286 sched_set_fifo(current);287 288 dev = this_cpu_read(cpuidle_devices);289 drv = cpuidle_get_cpu_driver(dev);290 291 pr_info("CPU %d entering suspend cycles, states 1 through %d\n",292 cpu, drv->state_count - 1);293 294 timer_setup_on_stack(&wakeup_timer, dummy_callback, 0);295 for (i = 0; i < NUM_SUSPEND_CYCLE; ++i) {296 int index;297 /*298 * Test all possible states, except 0 (which is usually WFI and299 * doesn't use PSCI).300 */301 for (index = 1; index < drv->state_count; ++index) {302 int ret;303 struct cpuidle_state *state = &drv->states[index];304 305 /*306 * Set the timer to wake this CPU up in some time (which307 * should be largely sufficient for entering suspend).308 * If the local tick is disabled when entering suspend,309 * suspend_cpu() takes care of switching to a broadcast310 * tick, so the timer will still wake us up.311 */312 mod_timer(&wakeup_timer, jiffies +313 usecs_to_jiffies(state->target_residency));314 315 /* IRQs must be disabled during suspend operations. */316 local_irq_disable();317 318 ret = suspend_cpu(dev, drv, index);319 320 /*321 * We have woken up. Re-enable IRQs to handle any322 * pending interrupt, do not wait until the end of the323 * loop.324 */325 local_irq_enable();326 327 if (ret == index) {328 ++nb_suspend;329 } else if (ret >= 0) {330 /* We did not enter the expected state. */331 ++nb_shallow_sleep;332 } else {333 pr_err("Failed to suspend CPU %d: error %d "334 "(requested state %d, cycle %d)\n",335 cpu, ret, index, i);336 ++nb_err;337 }338 }339 }340 341 /*342 * Disable the timer to make sure that the timer will not trigger343 * later.344 */345 del_timer(&wakeup_timer);346 destroy_timer_on_stack(&wakeup_timer);347 348 if (atomic_dec_return_relaxed(&nb_active_threads) == 0)349 complete(&suspend_threads_done);350 351 for (;;) {352 /* Needs to be set first to avoid missing a wakeup. */353 set_current_state(TASK_INTERRUPTIBLE);354 if (kthread_should_park())355 break;356 schedule();357 }358 359 pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n",360 cpu, nb_suspend, nb_shallow_sleep, nb_err);361 362 kthread_parkme();363 364 return nb_err;365}366 367static int suspend_tests(void)368{369 int i, cpu, err = 0;370 struct task_struct **threads;371 int nb_threads = 0;372 373 threads = kmalloc_array(nb_available_cpus, sizeof(*threads),374 GFP_KERNEL);375 if (!threads)376 return -ENOMEM;377 378 /*379 * Stop cpuidle to prevent the idle tasks from entering a deep sleep380 * mode, as it might interfere with the suspend threads on other CPUs.381 * This does not prevent the suspend threads from using cpuidle (only382 * the idle tasks check this status). Take the idle lock so that383 * the cpuidle driver and device look-up can be carried out safely.384 */385 cpuidle_pause_and_lock();386 387 for_each_online_cpu(cpu) {388 struct task_struct *thread;389 /* Check that cpuidle is available on that CPU. */390 struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);391 struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);392 393 if (!dev || !drv) {394 pr_warn("cpuidle not available on CPU %d, ignoring\n",395 cpu);396 continue;397 }398 399 thread = kthread_create_on_cpu(suspend_test_thread,400 (void *)(long)cpu, cpu,401 "psci_suspend_test");402 if (IS_ERR(thread))403 pr_err("Failed to create kthread on CPU %d\n", cpu);404 else405 threads[nb_threads++] = thread;406 }407 408 if (nb_threads < 1) {409 err = -ENODEV;410 goto out;411 }412 413 atomic_set(&nb_active_threads, nb_threads);414 415 /*416 * Wake up the suspend threads. To avoid the main thread being preempted417 * before all the threads have been unparked, the suspend threads will418 * wait for the completion of suspend_threads_started.419 */420 for (i = 0; i < nb_threads; ++i)421 wake_up_process(threads[i]);422 complete_all(&suspend_threads_started);423 424 wait_for_completion(&suspend_threads_done);425 426 427 /* Stop and destroy all threads, get return status. */428 for (i = 0; i < nb_threads; ++i) {429 err += kthread_park(threads[i]);430 err += kthread_stop(threads[i]);431 }432 out:433 cpuidle_resume_and_unlock();434 kfree(threads);435 return err;436}437 438static int __init psci_checker(void)439{440 int ret;441 442 /*443 * Since we're in an initcall, we assume that all the CPUs that all444 * CPUs that can be onlined have been onlined.445 *446 * The tests assume that hotplug is enabled but nobody else is using it,447 * otherwise the results will be unpredictable. However, since there448 * is no userspace yet in initcalls, that should be fine, as long as449 * no torture test is running at the same time (see Kconfig).450 */451 nb_available_cpus = num_online_cpus();452 453 /* Check PSCI operations are set up and working. */454 ret = psci_ops_check();455 if (ret)456 return ret;457 458 pr_info("PSCI checker started using %u CPUs\n", nb_available_cpus);459 460 pr_info("Starting hotplug tests\n");461 ret = hotplug_tests();462 if (ret == 0)463 pr_info("Hotplug tests passed OK\n");464 else if (ret > 0)465 pr_err("%d error(s) encountered in hotplug tests\n", ret);466 else {467 pr_err("Out of memory\n");468 return ret;469 }470 471 pr_info("Starting suspend tests (%d cycles per state)\n",472 NUM_SUSPEND_CYCLE);473 ret = suspend_tests();474 if (ret == 0)475 pr_info("Suspend tests passed OK\n");476 else if (ret > 0)477 pr_err("%d error(s) encountered in suspend tests\n", ret);478 else {479 switch (ret) {480 case -ENOMEM:481 pr_err("Out of memory\n");482 break;483 case -ENODEV:484 pr_warn("Could not start suspend tests on any CPU\n");485 break;486 }487 }488 489 pr_info("PSCI checker completed\n");490 return ret < 0 ? ret : 0;491}492late_initcall(psci_checker);493