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492 lines
12 KiB
492 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* |
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* Copyright (C) 2016 ARM Limited |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/atomic.h> |
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#include <linux/completion.h> |
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#include <linux/cpu.h> |
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#include <linux/cpuidle.h> |
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#include <linux/cpu_pm.h> |
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#include <linux/kernel.h> |
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#include <linux/kthread.h> |
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#include <uapi/linux/sched/types.h> |
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#include <linux/module.h> |
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#include <linux/preempt.h> |
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#include <linux/psci.h> |
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#include <linux/slab.h> |
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#include <linux/tick.h> |
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#include <linux/topology.h> |
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#include <asm/cpuidle.h> |
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#include <uapi/linux/psci.h> |
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#define NUM_SUSPEND_CYCLE (10) |
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static unsigned int nb_available_cpus; |
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static int tos_resident_cpu = -1; |
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static atomic_t nb_active_threads; |
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static struct completion suspend_threads_started = |
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COMPLETION_INITIALIZER(suspend_threads_started); |
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static struct completion suspend_threads_done = |
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COMPLETION_INITIALIZER(suspend_threads_done); |
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/* |
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* We assume that PSCI operations are used if they are available. This is not |
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* necessarily true on arm64, since the decision is based on the |
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* "enable-method" property of each CPU in the DT, but given that there is no |
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* arch-specific way to check this, we assume that the DT is sensible. |
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*/ |
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static int psci_ops_check(void) |
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{ |
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int migrate_type = -1; |
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int cpu; |
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if (!(psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend)) { |
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pr_warn("Missing PSCI operations, aborting tests\n"); |
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return -EOPNOTSUPP; |
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} |
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if (psci_ops.migrate_info_type) |
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migrate_type = psci_ops.migrate_info_type(); |
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if (migrate_type == PSCI_0_2_TOS_UP_MIGRATE || |
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migrate_type == PSCI_0_2_TOS_UP_NO_MIGRATE) { |
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/* There is a UP Trusted OS, find on which core it resides. */ |
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for_each_online_cpu(cpu) |
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if (psci_tos_resident_on(cpu)) { |
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tos_resident_cpu = cpu; |
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break; |
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} |
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if (tos_resident_cpu == -1) |
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pr_warn("UP Trusted OS resides on no online CPU\n"); |
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} |
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return 0; |
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} |
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/* |
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* offlined_cpus is a temporary array but passing it as an argument avoids |
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* multiple allocations. |
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*/ |
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static unsigned int down_and_up_cpus(const struct cpumask *cpus, |
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struct cpumask *offlined_cpus) |
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{ |
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int cpu; |
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int err = 0; |
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cpumask_clear(offlined_cpus); |
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/* Try to power down all CPUs in the mask. */ |
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for_each_cpu(cpu, cpus) { |
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int ret = remove_cpu(cpu); |
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/* |
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* cpu_down() checks the number of online CPUs before the TOS |
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* resident CPU. |
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*/ |
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if (cpumask_weight(offlined_cpus) + 1 == nb_available_cpus) { |
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if (ret != -EBUSY) { |
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pr_err("Unexpected return code %d while trying " |
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"to power down last online CPU %d\n", |
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ret, cpu); |
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++err; |
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} |
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} else if (cpu == tos_resident_cpu) { |
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if (ret != -EPERM) { |
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pr_err("Unexpected return code %d while trying " |
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"to power down TOS resident CPU %d\n", |
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ret, cpu); |
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++err; |
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} |
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} else if (ret != 0) { |
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pr_err("Error occurred (%d) while trying " |
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"to power down CPU %d\n", ret, cpu); |
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++err; |
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} |
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if (ret == 0) |
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cpumask_set_cpu(cpu, offlined_cpus); |
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} |
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/* Try to power up all the CPUs that have been offlined. */ |
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for_each_cpu(cpu, offlined_cpus) { |
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int ret = add_cpu(cpu); |
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if (ret != 0) { |
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pr_err("Error occurred (%d) while trying " |
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"to power up CPU %d\n", ret, cpu); |
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++err; |
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} else { |
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cpumask_clear_cpu(cpu, offlined_cpus); |
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} |
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} |
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/* |
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* Something went bad at some point and some CPUs could not be turned |
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* back on. |
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*/ |
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WARN_ON(!cpumask_empty(offlined_cpus) || |
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num_online_cpus() != nb_available_cpus); |
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return err; |
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} |
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static void free_cpu_groups(int num, cpumask_var_t **pcpu_groups) |
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{ |
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int i; |
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cpumask_var_t *cpu_groups = *pcpu_groups; |
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for (i = 0; i < num; ++i) |
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free_cpumask_var(cpu_groups[i]); |
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kfree(cpu_groups); |
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} |
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static int alloc_init_cpu_groups(cpumask_var_t **pcpu_groups) |
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{ |
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int num_groups = 0; |
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cpumask_var_t tmp, *cpu_groups; |
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if (!alloc_cpumask_var(&tmp, GFP_KERNEL)) |
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return -ENOMEM; |
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cpu_groups = kcalloc(nb_available_cpus, sizeof(cpu_groups), |
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GFP_KERNEL); |
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if (!cpu_groups) { |
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free_cpumask_var(tmp); |
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return -ENOMEM; |
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} |
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cpumask_copy(tmp, cpu_online_mask); |
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while (!cpumask_empty(tmp)) { |
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const struct cpumask *cpu_group = |
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topology_core_cpumask(cpumask_any(tmp)); |
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if (!alloc_cpumask_var(&cpu_groups[num_groups], GFP_KERNEL)) { |
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free_cpumask_var(tmp); |
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free_cpu_groups(num_groups, &cpu_groups); |
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return -ENOMEM; |
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} |
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cpumask_copy(cpu_groups[num_groups++], cpu_group); |
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cpumask_andnot(tmp, tmp, cpu_group); |
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} |
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free_cpumask_var(tmp); |
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*pcpu_groups = cpu_groups; |
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return num_groups; |
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} |
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static int hotplug_tests(void) |
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{ |
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int i, nb_cpu_group, err = -ENOMEM; |
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cpumask_var_t offlined_cpus, *cpu_groups; |
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char *page_buf; |
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if (!alloc_cpumask_var(&offlined_cpus, GFP_KERNEL)) |
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return err; |
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nb_cpu_group = alloc_init_cpu_groups(&cpu_groups); |
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if (nb_cpu_group < 0) |
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goto out_free_cpus; |
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page_buf = (char *)__get_free_page(GFP_KERNEL); |
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if (!page_buf) |
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goto out_free_cpu_groups; |
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/* |
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* Of course the last CPU cannot be powered down and cpu_down() should |
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* refuse doing that. |
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*/ |
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pr_info("Trying to turn off and on again all CPUs\n"); |
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err = down_and_up_cpus(cpu_online_mask, offlined_cpus); |
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/* |
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* Take down CPUs by cpu group this time. When the last CPU is turned |
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* off, the cpu group itself should shut down. |
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*/ |
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for (i = 0; i < nb_cpu_group; ++i) { |
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ssize_t len = cpumap_print_to_pagebuf(true, page_buf, |
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cpu_groups[i]); |
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/* Remove trailing newline. */ |
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page_buf[len - 1] = '\0'; |
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pr_info("Trying to turn off and on again group %d (CPUs %s)\n", |
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i, page_buf); |
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err += down_and_up_cpus(cpu_groups[i], offlined_cpus); |
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} |
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free_page((unsigned long)page_buf); |
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out_free_cpu_groups: |
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free_cpu_groups(nb_cpu_group, &cpu_groups); |
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out_free_cpus: |
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free_cpumask_var(offlined_cpus); |
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return err; |
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} |
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static void dummy_callback(struct timer_list *unused) {} |
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static int suspend_cpu(struct cpuidle_device *dev, |
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struct cpuidle_driver *drv, int index) |
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{ |
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struct cpuidle_state *state = &drv->states[index]; |
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bool broadcast = state->flags & CPUIDLE_FLAG_TIMER_STOP; |
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int ret; |
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arch_cpu_idle_enter(); |
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if (broadcast) { |
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/* |
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* The local timer will be shut down, we need to enter tick |
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* broadcast. |
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*/ |
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ret = tick_broadcast_enter(); |
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if (ret) { |
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/* |
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* In the absence of hardware broadcast mechanism, |
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* this CPU might be used to broadcast wakeups, which |
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* may be why entering tick broadcast has failed. |
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* There is little the kernel can do to work around |
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* that, so enter WFI instead (idle state 0). |
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*/ |
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cpu_do_idle(); |
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ret = 0; |
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goto out_arch_exit; |
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} |
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} |
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ret = state->enter(dev, drv, index); |
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if (broadcast) |
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tick_broadcast_exit(); |
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out_arch_exit: |
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arch_cpu_idle_exit(); |
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return ret; |
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} |
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static int suspend_test_thread(void *arg) |
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{ |
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int cpu = (long)arg; |
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int i, nb_suspend = 0, nb_shallow_sleep = 0, nb_err = 0; |
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struct cpuidle_device *dev; |
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struct cpuidle_driver *drv; |
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/* No need for an actual callback, we just want to wake up the CPU. */ |
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struct timer_list wakeup_timer; |
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/* Wait for the main thread to give the start signal. */ |
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wait_for_completion(&suspend_threads_started); |
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/* Set maximum priority to preempt all other threads on this CPU. */ |
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sched_set_fifo(current); |
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dev = this_cpu_read(cpuidle_devices); |
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drv = cpuidle_get_cpu_driver(dev); |
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pr_info("CPU %d entering suspend cycles, states 1 through %d\n", |
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cpu, drv->state_count - 1); |
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timer_setup_on_stack(&wakeup_timer, dummy_callback, 0); |
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for (i = 0; i < NUM_SUSPEND_CYCLE; ++i) { |
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int index; |
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/* |
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* Test all possible states, except 0 (which is usually WFI and |
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* doesn't use PSCI). |
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*/ |
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for (index = 1; index < drv->state_count; ++index) { |
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int ret; |
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struct cpuidle_state *state = &drv->states[index]; |
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/* |
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* Set the timer to wake this CPU up in some time (which |
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* should be largely sufficient for entering suspend). |
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* If the local tick is disabled when entering suspend, |
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* suspend_cpu() takes care of switching to a broadcast |
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* tick, so the timer will still wake us up. |
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*/ |
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mod_timer(&wakeup_timer, jiffies + |
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usecs_to_jiffies(state->target_residency)); |
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/* IRQs must be disabled during suspend operations. */ |
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local_irq_disable(); |
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ret = suspend_cpu(dev, drv, index); |
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/* |
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* We have woken up. Re-enable IRQs to handle any |
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* pending interrupt, do not wait until the end of the |
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* loop. |
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*/ |
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local_irq_enable(); |
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if (ret == index) { |
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++nb_suspend; |
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} else if (ret >= 0) { |
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/* We did not enter the expected state. */ |
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++nb_shallow_sleep; |
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} else { |
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pr_err("Failed to suspend CPU %d: error %d " |
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"(requested state %d, cycle %d)\n", |
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cpu, ret, index, i); |
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++nb_err; |
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} |
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} |
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} |
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/* |
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* Disable the timer to make sure that the timer will not trigger |
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* later. |
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*/ |
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del_timer(&wakeup_timer); |
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destroy_timer_on_stack(&wakeup_timer); |
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if (atomic_dec_return_relaxed(&nb_active_threads) == 0) |
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complete(&suspend_threads_done); |
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for (;;) { |
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/* Needs to be set first to avoid missing a wakeup. */ |
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set_current_state(TASK_INTERRUPTIBLE); |
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if (kthread_should_park()) |
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break; |
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schedule(); |
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} |
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pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n", |
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cpu, nb_suspend, nb_shallow_sleep, nb_err); |
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kthread_parkme(); |
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return nb_err; |
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} |
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static int suspend_tests(void) |
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{ |
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int i, cpu, err = 0; |
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struct task_struct **threads; |
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int nb_threads = 0; |
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threads = kmalloc_array(nb_available_cpus, sizeof(*threads), |
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GFP_KERNEL); |
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if (!threads) |
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return -ENOMEM; |
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/* |
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* Stop cpuidle to prevent the idle tasks from entering a deep sleep |
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* mode, as it might interfere with the suspend threads on other CPUs. |
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* This does not prevent the suspend threads from using cpuidle (only |
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* the idle tasks check this status). Take the idle lock so that |
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* the cpuidle driver and device look-up can be carried out safely. |
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*/ |
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cpuidle_pause_and_lock(); |
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for_each_online_cpu(cpu) { |
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struct task_struct *thread; |
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/* Check that cpuidle is available on that CPU. */ |
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struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); |
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struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
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if (!dev || !drv) { |
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pr_warn("cpuidle not available on CPU %d, ignoring\n", |
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cpu); |
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continue; |
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} |
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thread = kthread_create_on_cpu(suspend_test_thread, |
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(void *)(long)cpu, cpu, |
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"psci_suspend_test"); |
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if (IS_ERR(thread)) |
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pr_err("Failed to create kthread on CPU %d\n", cpu); |
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else |
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threads[nb_threads++] = thread; |
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} |
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if (nb_threads < 1) { |
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err = -ENODEV; |
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goto out; |
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} |
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atomic_set(&nb_active_threads, nb_threads); |
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/* |
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* Wake up the suspend threads. To avoid the main thread being preempted |
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* before all the threads have been unparked, the suspend threads will |
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* wait for the completion of suspend_threads_started. |
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*/ |
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for (i = 0; i < nb_threads; ++i) |
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wake_up_process(threads[i]); |
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complete_all(&suspend_threads_started); |
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wait_for_completion(&suspend_threads_done); |
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/* Stop and destroy all threads, get return status. */ |
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for (i = 0; i < nb_threads; ++i) { |
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err += kthread_park(threads[i]); |
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err += kthread_stop(threads[i]); |
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} |
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out: |
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cpuidle_resume_and_unlock(); |
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kfree(threads); |
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return err; |
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} |
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static int __init psci_checker(void) |
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{ |
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int ret; |
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/* |
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* Since we're in an initcall, we assume that all the CPUs that all |
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* CPUs that can be onlined have been onlined. |
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* |
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* The tests assume that hotplug is enabled but nobody else is using it, |
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* otherwise the results will be unpredictable. However, since there |
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* is no userspace yet in initcalls, that should be fine, as long as |
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* no torture test is running at the same time (see Kconfig). |
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*/ |
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nb_available_cpus = num_online_cpus(); |
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/* Check PSCI operations are set up and working. */ |
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ret = psci_ops_check(); |
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if (ret) |
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return ret; |
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pr_info("PSCI checker started using %u CPUs\n", nb_available_cpus); |
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pr_info("Starting hotplug tests\n"); |
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ret = hotplug_tests(); |
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if (ret == 0) |
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pr_info("Hotplug tests passed OK\n"); |
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else if (ret > 0) |
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pr_err("%d error(s) encountered in hotplug tests\n", ret); |
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else { |
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pr_err("Out of memory\n"); |
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return ret; |
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} |
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pr_info("Starting suspend tests (%d cycles per state)\n", |
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NUM_SUSPEND_CYCLE); |
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ret = suspend_tests(); |
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if (ret == 0) |
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pr_info("Suspend tests passed OK\n"); |
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else if (ret > 0) |
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pr_err("%d error(s) encountered in suspend tests\n", ret); |
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else { |
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switch (ret) { |
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case -ENOMEM: |
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pr_err("Out of memory\n"); |
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break; |
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case -ENODEV: |
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pr_warn("Could not start suspend tests on any CPU\n"); |
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break; |
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} |
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} |
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pr_info("PSCI checker completed\n"); |
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return ret < 0 ? ret : 0; |
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} |
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late_initcall(psci_checker);
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