1 files changed, 505 insertions, 0 deletions

diff --git a/drivers/firmware/psci/psci_checker.c b/drivers/firmware/psci/psci_checker.c
new file mode 100644
index 000000000000..346943657962
--- /dev/null
+++ b/drivers/firmware/psci/psci_checker.c
@@ -0,0 +1,505 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Copyright (C) 2016 ARM Limited
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/completion.h>
+#include <linux/cpu.h>
+#include <linux/cpuidle.h>
+#include <linux/cpu_pm.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/module.h>
+#include <linux/preempt.h>
+#include <linux/psci.h>
+#include <linux/slab.h>
+#include <linux/tick.h>
+#include <linux/topology.h>
+
+#include <asm/cpuidle.h>
+
+#include <uapi/linux/psci.h>
+
+#define NUM_SUSPEND_CYCLE (10)
+
+static unsigned int nb_available_cpus;
+static int tos_resident_cpu = -1;
+
+static atomic_t nb_active_threads;
+static struct completion suspend_threads_started =
+        COMPLETION_INITIALIZER(suspend_threads_started);
+static struct completion suspend_threads_done =
+        COMPLETION_INITIALIZER(suspend_threads_done);
+
+/*
+ * We assume that PSCI operations are used if they are available. This is not
+ * necessarily true on arm64, since the decision is based on the
+ * "enable-method" property of each CPU in the DT, but given that there is no
+ * arch-specific way to check this, we assume that the DT is sensible.
+ */
+static int psci_ops_check(void)
+{
+        int migrate_type = -1;
+        int cpu;
+
+        if (!(psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend)) {
+                pr_warn("Missing PSCI operations, aborting tests\n");
+                return -EOPNOTSUPP;
+        }
+
+        if (psci_ops.migrate_info_type)
+                migrate_type = psci_ops.migrate_info_type();
+
+        if (migrate_type == PSCI_0_2_TOS_UP_MIGRATE ||
+            migrate_type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
+                /* There is a UP Trusted OS, find on which core it resides. */
+                for_each_online_cpu(cpu)
+                        if (psci_tos_resident_on(cpu)) {
+                                tos_resident_cpu = cpu;
+                                break;
+                        }
+                if (tos_resident_cpu == -1)
+                        pr_warn("UP Trusted OS resides on no online CPU\n");
+        }
+
+        return 0;
+}
+
+/*
+ * offlined_cpus is a temporary array but passing it as an argument avoids
+ * multiple allocations.
+ */
+static unsigned int down_and_up_cpus(const struct cpumask *cpus,
+                                     struct cpumask *offlined_cpus)
+{
+        int cpu;
+        int err = 0;
+
+        cpumask_clear(offlined_cpus);
+
+        /* Try to power down all CPUs in the mask. */
+        for_each_cpu(cpu, cpus) {
+                int ret = cpu_down(cpu);
+
+                /*
+                 * cpu_down() checks the number of online CPUs before the TOS
+                 * resident CPU.
+                 */
+                if (cpumask_weight(offlined_cpus) + 1 == nb_available_cpus) {
+                        if (ret != -EBUSY) {
+                                pr_err("Unexpected return code %d while trying "
+                                       "to power down last online CPU %d\n",
+                                       ret, cpu);
+                                ++err;
+                        }
+                } else if (cpu == tos_resident_cpu) {
+                        if (ret != -EPERM) {
+                                pr_err("Unexpected return code %d while trying "
+                                       "to power down TOS resident CPU %d\n",
+                                       ret, cpu);
+                                ++err;
+                        }
+                } else if (ret != 0) {
+                        pr_err("Error occurred (%d) while trying "
+                               "to power down CPU %d\n", ret, cpu);
+                        ++err;
+                }
+
+                if (ret == 0)
+                        cpumask_set_cpu(cpu, offlined_cpus);
+        }
+
+        /* Try to power up all the CPUs that have been offlined. */
+        for_each_cpu(cpu, offlined_cpus) {
+                int ret = cpu_up(cpu);
+
+                if (ret != 0) {
+                        pr_err("Error occurred (%d) while trying "
+                               "to power up CPU %d\n", ret, cpu);
+                        ++err;
+                } else {
+                        cpumask_clear_cpu(cpu, offlined_cpus);
+                }
+        }
+
+        /*
+         * Something went bad at some point and some CPUs could not be turned
+         * back on.
+         */
+        WARN_ON(!cpumask_empty(offlined_cpus) ||
+                num_online_cpus() != nb_available_cpus);
+
+        return err;
+}
+
+static void free_cpu_groups(int num, cpumask_var_t **pcpu_groups)
+{
+        int i;
+        cpumask_var_t *cpu_groups = *pcpu_groups;
+
+        for (i = 0; i < num; ++i)
+                free_cpumask_var(cpu_groups[i]);
+        kfree(cpu_groups);
+}
+
+static int alloc_init_cpu_groups(cpumask_var_t **pcpu_groups)
+{
+        int num_groups = 0;
+        cpumask_var_t tmp, *cpu_groups;
+
+        if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
+                return -ENOMEM;
+
+        cpu_groups = kcalloc(nb_available_cpus, sizeof(cpu_groups),
+                             GFP_KERNEL);
+        if (!cpu_groups)
+                return -ENOMEM;
+
+        cpumask_copy(tmp, cpu_online_mask);
+
+        while (!cpumask_empty(tmp)) {
+                const struct cpumask *cpu_group =
+                        topology_core_cpumask(cpumask_any(tmp));
+
+                if (!alloc_cpumask_var(&cpu_groups[num_groups], GFP_KERNEL)) {
+                        free_cpu_groups(num_groups, &cpu_groups);
+                        return -ENOMEM;
+                }
+                cpumask_copy(cpu_groups[num_groups++], cpu_group);
+                cpumask_andnot(tmp, tmp, cpu_group);
+        }
+
+        free_cpumask_var(tmp);
+        *pcpu_groups = cpu_groups;
+
+        return num_groups;
+}
+
+static int hotplug_tests(void)
+{
+        int i, nb_cpu_group, err = -ENOMEM;
+        cpumask_var_t offlined_cpus, *cpu_groups;
+        char *page_buf;
+
+        if (!alloc_cpumask_var(&offlined_cpus, GFP_KERNEL))
+                return err;
+
+        nb_cpu_group = alloc_init_cpu_groups(&cpu_groups);
+        if (nb_cpu_group < 0)
+                goto out_free_cpus;
+        page_buf = (char *)__get_free_page(GFP_KERNEL);
+        if (!page_buf)
+                goto out_free_cpu_groups;
+
+        err = 0;
+        /*
+         * Of course the last CPU cannot be powered down and cpu_down() should
+         * refuse doing that.
+         */
+        pr_info("Trying to turn off and on again all CPUs\n");
+        err += down_and_up_cpus(cpu_online_mask, offlined_cpus);
+
+        /*
+         * Take down CPUs by cpu group this time. When the last CPU is turned
+         * off, the cpu group itself should shut down.
+         */
+        for (i = 0; i < nb_cpu_group; ++i) {
+                ssize_t len = cpumap_print_to_pagebuf(true, page_buf,
+                                                      cpu_groups[i]);
+                /* Remove trailing newline. */
+                page_buf[len - 1] = '\0';
+                pr_info("Trying to turn off and on again group %d (CPUs %s)\n",
+                        i, page_buf);
+                err += down_and_up_cpus(cpu_groups[i], offlined_cpus);
+        }
+
+        free_page((unsigned long)page_buf);
+out_free_cpu_groups:
+        free_cpu_groups(nb_cpu_group, &cpu_groups);
+out_free_cpus:
+        free_cpumask_var(offlined_cpus);
+        return err;
+}
+
+static void dummy_callback(struct timer_list *unused) {}
+
+static int suspend_cpu(int index, bool broadcast)
+{
+        int ret;
+
+        arch_cpu_idle_enter();
+
+        if (broadcast) {
+                /*
+                 * The local timer will be shut down, we need to enter tick
+                 * broadcast.
+                 */
+                ret = tick_broadcast_enter();
+                if (ret) {
+                        /*
+                         * In the absence of hardware broadcast mechanism,
+                         * this CPU might be used to broadcast wakeups, which
+                         * may be why entering tick broadcast has failed.
+                         * There is little the kernel can do to work around
+                         * that, so enter WFI instead (idle state 0).
+                         */
+                        cpu_do_idle();
+                        ret = 0;
+                        goto out_arch_exit;
+                }
+        }
+
+        /*
+         * Replicate the common ARM cpuidle enter function
+         * (arm_enter_idle_state).
+         */
+        ret = CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, index);
+
+        if (broadcast)
+                tick_broadcast_exit();
+
+out_arch_exit:
+        arch_cpu_idle_exit();
+
+        return ret;
+}
+
+static int suspend_test_thread(void *arg)
+{
+        int cpu = (long)arg;
+        int i, nb_suspend = 0, nb_shallow_sleep = 0, nb_err = 0;
+        struct sched_param sched_priority = { .sched_priority = MAX_RT_PRIO-1 };
+        struct cpuidle_device *dev;
+        struct cpuidle_driver *drv;
+        /* No need for an actual callback, we just want to wake up the CPU. */
+        struct timer_list wakeup_timer;
+
+        /* Wait for the main thread to give the start signal. */
+        wait_for_completion(&suspend_threads_started);
+
+        /* Set maximum priority to preempt all other threads on this CPU. */
+        if (sched_setscheduler_nocheck(current, SCHED_FIFO, &sched_priority))
+                pr_warn("Failed to set suspend thread scheduler on CPU %d\n",
+                        cpu);
+
+        dev = this_cpu_read(cpuidle_devices);
+        drv = cpuidle_get_cpu_driver(dev);
+
+        pr_info("CPU %d entering suspend cycles, states 1 through %d\n",
+                cpu, drv->state_count - 1);
+
+        timer_setup_on_stack(&wakeup_timer, dummy_callback, 0);
+        for (i = 0; i < NUM_SUSPEND_CYCLE; ++i) {
+                int index;
+                /*
+                 * Test all possible states, except 0 (which is usually WFI and
+                 * doesn't use PSCI).
+                 */
+                for (index = 1; index < drv->state_count; ++index) {
+                        struct cpuidle_state *state = &drv->states[index];
+                        bool broadcast = state->flags & CPUIDLE_FLAG_TIMER_STOP;
+                        int ret;
+
+                        /*
+                         * Set the timer to wake this CPU up in some time (which
+                         * should be largely sufficient for entering suspend).
+                         * If the local tick is disabled when entering suspend,
+                         * suspend_cpu() takes care of switching to a broadcast
+                         * tick, so the timer will still wake us up.
+                         */
+                        mod_timer(&wakeup_timer, jiffies +
+                                  usecs_to_jiffies(state->target_residency));
+
+                        /* IRQs must be disabled during suspend operations. */
+                        local_irq_disable();
+
+                        ret = suspend_cpu(index, broadcast);
+
+                        /*
+                         * We have woken up. Re-enable IRQs to handle any
+                         * pending interrupt, do not wait until the end of the
+                         * loop.
+                         */
+                        local_irq_enable();
+
+                        if (ret == index) {
+                                ++nb_suspend;
+                        } else if (ret >= 0) {
+                                /* We did not enter the expected state. */
+                                ++nb_shallow_sleep;
+                        } else {
+                                pr_err("Failed to suspend CPU %d: error %d "
+                                       "(requested state %d, cycle %d)\n",
+                                       cpu, ret, index, i);
+                                ++nb_err;
+                        }
+                }
+        }
+
+        /*
+         * Disable the timer to make sure that the timer will not trigger
+         * later.
+         */
+        del_timer(&wakeup_timer);
+        destroy_timer_on_stack(&wakeup_timer);
+
+        if (atomic_dec_return_relaxed(&nb_active_threads) == 0)
+                complete(&suspend_threads_done);
+
+        /* Give up on RT scheduling and wait for termination. */
+        sched_priority.sched_priority = 0;
+        if (sched_setscheduler_nocheck(current, SCHED_NORMAL, &sched_priority))
+                pr_warn("Failed to set suspend thread scheduler on CPU %d\n",
+                        cpu);
+        for (;;) {
+                /* Needs to be set first to avoid missing a wakeup. */
+                set_current_state(TASK_INTERRUPTIBLE);
+                if (kthread_should_stop()) {
+                        __set_current_state(TASK_RUNNING);
+                        break;
+                }
+                schedule();
+        }
+
+        pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n",
+                cpu, nb_suspend, nb_shallow_sleep, nb_err);
+
+        return nb_err;
+}
+
+static int suspend_tests(void)
+{
+        int i, cpu, err = 0;
+        struct task_struct **threads;
+        int nb_threads = 0;
+
+        threads = kmalloc_array(nb_available_cpus, sizeof(*threads),
+                                GFP_KERNEL);
+        if (!threads)
+                return -ENOMEM;
+
+        /*
+         * Stop cpuidle to prevent the idle tasks from entering a deep sleep
+         * mode, as it might interfere with the suspend threads on other CPUs.
+         * This does not prevent the suspend threads from using cpuidle (only
+         * the idle tasks check this status). Take the idle lock so that
+         * the cpuidle driver and device look-up can be carried out safely.
+         */
+        cpuidle_pause_and_lock();
+
+        for_each_online_cpu(cpu) {
+                struct task_struct *thread;
+                /* Check that cpuidle is available on that CPU. */
+                struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
+                struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
+
+                if (!dev || !drv) {
+                        pr_warn("cpuidle not available on CPU %d, ignoring\n",
+                                cpu);
+                        continue;
+                }
+
+                thread = kthread_create_on_cpu(suspend_test_thread,
+                                               (void *)(long)cpu, cpu,
+                                               "psci_suspend_test");
+                if (IS_ERR(thread))
+                        pr_err("Failed to create kthread on CPU %d\n", cpu);
+                else
+                        threads[nb_threads++] = thread;
+        }
+
+        if (nb_threads < 1) {
+                err = -ENODEV;
+                goto out;
+        }
+
+        atomic_set(&nb_active_threads, nb_threads);
+
+        /*
+         * Wake up the suspend threads. To avoid the main thread being preempted
+         * before all the threads have been unparked, the suspend threads will
+         * wait for the completion of suspend_threads_started.
+         */
+        for (i = 0; i < nb_threads; ++i)
+                wake_up_process(threads[i]);
+        complete_all(&suspend_threads_started);
+
+        wait_for_completion(&suspend_threads_done);
+
+
+        /* Stop and destroy all threads, get return status. */
+        for (i = 0; i < nb_threads; ++i)
+                err += kthread_stop(threads[i]);
+ out:
+        cpuidle_resume_and_unlock();
+        kfree(threads);
+        return err;
+}
+
+static int __init psci_checker(void)
+{
+        int ret;
+
+        /*
+         * Since we're in an initcall, we assume that all the CPUs that all
+         * CPUs that can be onlined have been onlined.
+         *
+         * The tests assume that hotplug is enabled but nobody else is using it,
+         * otherwise the results will be unpredictable. However, since there
+         * is no userspace yet in initcalls, that should be fine, as long as
+         * no torture test is running at the same time (see Kconfig).
+         */
+        nb_available_cpus = num_online_cpus();
+
+        /* Check PSCI operations are set up and working. */
+        ret = psci_ops_check();
+        if (ret)
+                return ret;
+
+        pr_info("PSCI checker started using %u CPUs\n", nb_available_cpus);
+
+        pr_info("Starting hotplug tests\n");
+        ret = hotplug_tests();
+        if (ret == 0)
+                pr_info("Hotplug tests passed OK\n");
+        else if (ret > 0)
+                pr_err("%d error(s) encountered in hotplug tests\n", ret);
+        else {
+                pr_err("Out of memory\n");
+                return ret;
+        }
+
+        pr_info("Starting suspend tests (%d cycles per state)\n",
+                NUM_SUSPEND_CYCLE);
+        ret = suspend_tests();
+        if (ret == 0)
+                pr_info("Suspend tests passed OK\n");
+        else if (ret > 0)
+                pr_err("%d error(s) encountered in suspend tests\n", ret);
+        else {
+                switch (ret) {
+                case -ENOMEM:
+                        pr_err("Out of memory\n");
+                        break;
+                case -ENODEV:
+                        pr_warn("Could not start suspend tests on any CPU\n");
+                        break;
+                }
+        }
+
+        pr_info("PSCI checker completed\n");
+        return ret < 0 ? ret : 0;
+}
+late_initcall(psci_checker);