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613 lines
15 KiB
613 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* CPU subsystem support |
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*/ |
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|
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/sched.h> |
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#include <linux/cpu.h> |
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#include <linux/topology.h> |
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#include <linux/device.h> |
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#include <linux/node.h> |
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#include <linux/gfp.h> |
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#include <linux/slab.h> |
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#include <linux/percpu.h> |
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#include <linux/acpi.h> |
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#include <linux/of.h> |
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#include <linux/cpufeature.h> |
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#include <linux/tick.h> |
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#include <linux/pm_qos.h> |
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#include <linux/sched/isolation.h> |
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#include "base.h" |
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static DEFINE_PER_CPU(struct device *, cpu_sys_devices); |
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static int cpu_subsys_match(struct device *dev, struct device_driver *drv) |
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{ |
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/* ACPI style match is the only one that may succeed. */ |
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if (acpi_driver_match_device(dev, drv)) |
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return 1; |
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return 0; |
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} |
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#ifdef CONFIG_HOTPLUG_CPU |
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static void change_cpu_under_node(struct cpu *cpu, |
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unsigned int from_nid, unsigned int to_nid) |
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{ |
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int cpuid = cpu->dev.id; |
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unregister_cpu_under_node(cpuid, from_nid); |
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register_cpu_under_node(cpuid, to_nid); |
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cpu->node_id = to_nid; |
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} |
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static int cpu_subsys_online(struct device *dev) |
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{ |
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struct cpu *cpu = container_of(dev, struct cpu, dev); |
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int cpuid = dev->id; |
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int from_nid, to_nid; |
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int ret; |
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from_nid = cpu_to_node(cpuid); |
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if (from_nid == NUMA_NO_NODE) |
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return -ENODEV; |
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ret = cpu_device_up(dev); |
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/* |
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* When hot adding memory to memoryless node and enabling a cpu |
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* on the node, node number of the cpu may internally change. |
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*/ |
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to_nid = cpu_to_node(cpuid); |
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if (from_nid != to_nid) |
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change_cpu_under_node(cpu, from_nid, to_nid); |
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return ret; |
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} |
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static int cpu_subsys_offline(struct device *dev) |
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{ |
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return cpu_device_down(dev); |
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} |
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void unregister_cpu(struct cpu *cpu) |
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{ |
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int logical_cpu = cpu->dev.id; |
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unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); |
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device_unregister(&cpu->dev); |
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per_cpu(cpu_sys_devices, logical_cpu) = NULL; |
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return; |
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} |
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#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE |
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static ssize_t cpu_probe_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, |
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size_t count) |
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{ |
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ssize_t cnt; |
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int ret; |
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ret = lock_device_hotplug_sysfs(); |
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if (ret) |
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return ret; |
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cnt = arch_cpu_probe(buf, count); |
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unlock_device_hotplug(); |
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return cnt; |
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} |
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static ssize_t cpu_release_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, |
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size_t count) |
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{ |
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ssize_t cnt; |
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int ret; |
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ret = lock_device_hotplug_sysfs(); |
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if (ret) |
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return ret; |
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cnt = arch_cpu_release(buf, count); |
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unlock_device_hotplug(); |
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return cnt; |
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} |
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static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); |
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static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store); |
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#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */ |
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#endif /* CONFIG_HOTPLUG_CPU */ |
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struct bus_type cpu_subsys = { |
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.name = "cpu", |
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.dev_name = "cpu", |
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.match = cpu_subsys_match, |
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#ifdef CONFIG_HOTPLUG_CPU |
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.online = cpu_subsys_online, |
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.offline = cpu_subsys_offline, |
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#endif |
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}; |
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EXPORT_SYMBOL_GPL(cpu_subsys); |
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#ifdef CONFIG_KEXEC |
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#include <linux/kexec.h> |
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static ssize_t crash_notes_show(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct cpu *cpu = container_of(dev, struct cpu, dev); |
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unsigned long long addr; |
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int cpunum; |
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cpunum = cpu->dev.id; |
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/* |
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* Might be reading other cpu's data based on which cpu read thread |
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* has been scheduled. But cpu data (memory) is allocated once during |
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* boot up and this data does not change there after. Hence this |
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* operation should be safe. No locking required. |
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*/ |
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addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum)); |
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return sysfs_emit(buf, "%llx\n", addr); |
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} |
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static DEVICE_ATTR_ADMIN_RO(crash_notes); |
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static ssize_t crash_notes_size_show(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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return sysfs_emit(buf, "%zu\n", sizeof(note_buf_t)); |
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} |
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static DEVICE_ATTR_ADMIN_RO(crash_notes_size); |
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static struct attribute *crash_note_cpu_attrs[] = { |
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&dev_attr_crash_notes.attr, |
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&dev_attr_crash_notes_size.attr, |
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NULL |
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}; |
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static const struct attribute_group crash_note_cpu_attr_group = { |
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.attrs = crash_note_cpu_attrs, |
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}; |
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#endif |
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static const struct attribute_group *common_cpu_attr_groups[] = { |
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#ifdef CONFIG_KEXEC |
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&crash_note_cpu_attr_group, |
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#endif |
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NULL |
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}; |
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static const struct attribute_group *hotplugable_cpu_attr_groups[] = { |
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#ifdef CONFIG_KEXEC |
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&crash_note_cpu_attr_group, |
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#endif |
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NULL |
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}; |
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/* |
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* Print cpu online, possible, present, and system maps |
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*/ |
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struct cpu_attr { |
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struct device_attribute attr; |
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const struct cpumask *const map; |
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}; |
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static ssize_t show_cpus_attr(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr); |
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return cpumap_print_to_pagebuf(true, buf, ca->map); |
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} |
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#define _CPU_ATTR(name, map) \ |
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{ __ATTR(name, 0444, show_cpus_attr, NULL), map } |
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/* Keep in sync with cpu_subsys_attrs */ |
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static struct cpu_attr cpu_attrs[] = { |
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_CPU_ATTR(online, &__cpu_online_mask), |
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_CPU_ATTR(possible, &__cpu_possible_mask), |
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_CPU_ATTR(present, &__cpu_present_mask), |
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}; |
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/* |
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* Print values for NR_CPUS and offlined cpus |
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*/ |
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static ssize_t print_cpus_kernel_max(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "%d\n", NR_CPUS - 1); |
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} |
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static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL); |
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/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */ |
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unsigned int total_cpus; |
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static ssize_t print_cpus_offline(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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int len = 0; |
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cpumask_var_t offline; |
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/* display offline cpus < nr_cpu_ids */ |
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if (!alloc_cpumask_var(&offline, GFP_KERNEL)) |
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return -ENOMEM; |
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cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask); |
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len += sysfs_emit_at(buf, len, "%*pbl", cpumask_pr_args(offline)); |
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free_cpumask_var(offline); |
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/* display offline cpus >= nr_cpu_ids */ |
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if (total_cpus && nr_cpu_ids < total_cpus) { |
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len += sysfs_emit_at(buf, len, ","); |
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if (nr_cpu_ids == total_cpus-1) |
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len += sysfs_emit_at(buf, len, "%u", nr_cpu_ids); |
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else |
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len += sysfs_emit_at(buf, len, "%u-%d", |
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nr_cpu_ids, total_cpus - 1); |
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} |
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len += sysfs_emit_at(buf, len, "\n"); |
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return len; |
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} |
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static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL); |
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static ssize_t print_cpus_isolated(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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int len; |
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cpumask_var_t isolated; |
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if (!alloc_cpumask_var(&isolated, GFP_KERNEL)) |
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return -ENOMEM; |
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cpumask_andnot(isolated, cpu_possible_mask, |
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housekeeping_cpumask(HK_FLAG_DOMAIN)); |
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len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated)); |
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free_cpumask_var(isolated); |
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return len; |
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} |
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static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL); |
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#ifdef CONFIG_NO_HZ_FULL |
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static ssize_t print_cpus_nohz_full(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask)); |
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} |
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static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL); |
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#endif |
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static void cpu_device_release(struct device *dev) |
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{ |
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/* |
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* This is an empty function to prevent the driver core from spitting a |
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* warning at us. Yes, I know this is directly opposite of what the |
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* documentation for the driver core and kobjects say, and the author |
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* of this code has already been publically ridiculed for doing |
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* something as foolish as this. However, at this point in time, it is |
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* the only way to handle the issue of statically allocated cpu |
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* devices. The different architectures will have their cpu device |
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* code reworked to properly handle this in the near future, so this |
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* function will then be changed to correctly free up the memory held |
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* by the cpu device. |
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* |
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* Never copy this way of doing things, or you too will be made fun of |
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* on the linux-kernel list, you have been warned. |
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*/ |
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} |
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#ifdef CONFIG_GENERIC_CPU_AUTOPROBE |
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static ssize_t print_cpu_modalias(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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int len = 0; |
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u32 i; |
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len += sysfs_emit_at(buf, len, |
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"cpu:type:" CPU_FEATURE_TYPEFMT ":feature:", |
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CPU_FEATURE_TYPEVAL); |
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for (i = 0; i < MAX_CPU_FEATURES; i++) |
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if (cpu_have_feature(i)) { |
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if (len + sizeof(",XXXX\n") >= PAGE_SIZE) { |
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WARN(1, "CPU features overflow page\n"); |
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break; |
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} |
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len += sysfs_emit_at(buf, len, ",%04X", i); |
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} |
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len += sysfs_emit_at(buf, len, "\n"); |
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return len; |
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} |
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static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env) |
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{ |
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char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL); |
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if (buf) { |
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print_cpu_modalias(NULL, NULL, buf); |
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add_uevent_var(env, "MODALIAS=%s", buf); |
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kfree(buf); |
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} |
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return 0; |
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} |
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#endif |
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/* |
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* register_cpu - Setup a sysfs device for a CPU. |
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* @cpu - cpu->hotpluggable field set to 1 will generate a control file in |
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* sysfs for this CPU. |
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* @num - CPU number to use when creating the device. |
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* |
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* Initialize and register the CPU device. |
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*/ |
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int register_cpu(struct cpu *cpu, int num) |
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{ |
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int error; |
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cpu->node_id = cpu_to_node(num); |
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memset(&cpu->dev, 0x00, sizeof(struct device)); |
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cpu->dev.id = num; |
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cpu->dev.bus = &cpu_subsys; |
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cpu->dev.release = cpu_device_release; |
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cpu->dev.offline_disabled = !cpu->hotpluggable; |
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cpu->dev.offline = !cpu_online(num); |
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cpu->dev.of_node = of_get_cpu_node(num, NULL); |
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#ifdef CONFIG_GENERIC_CPU_AUTOPROBE |
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cpu->dev.bus->uevent = cpu_uevent; |
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#endif |
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cpu->dev.groups = common_cpu_attr_groups; |
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if (cpu->hotpluggable) |
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cpu->dev.groups = hotplugable_cpu_attr_groups; |
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error = device_register(&cpu->dev); |
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if (error) { |
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put_device(&cpu->dev); |
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return error; |
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} |
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per_cpu(cpu_sys_devices, num) = &cpu->dev; |
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register_cpu_under_node(num, cpu_to_node(num)); |
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dev_pm_qos_expose_latency_limit(&cpu->dev, |
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PM_QOS_RESUME_LATENCY_NO_CONSTRAINT); |
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return 0; |
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} |
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struct device *get_cpu_device(unsigned cpu) |
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{ |
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if (cpu < nr_cpu_ids && cpu_possible(cpu)) |
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return per_cpu(cpu_sys_devices, cpu); |
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else |
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return NULL; |
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} |
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EXPORT_SYMBOL_GPL(get_cpu_device); |
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static void device_create_release(struct device *dev) |
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{ |
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kfree(dev); |
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} |
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__printf(4, 0) |
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static struct device * |
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__cpu_device_create(struct device *parent, void *drvdata, |
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const struct attribute_group **groups, |
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const char *fmt, va_list args) |
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{ |
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struct device *dev = NULL; |
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int retval = -ENOMEM; |
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dev = kzalloc(sizeof(*dev), GFP_KERNEL); |
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if (!dev) |
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goto error; |
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device_initialize(dev); |
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dev->parent = parent; |
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dev->groups = groups; |
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dev->release = device_create_release; |
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device_set_pm_not_required(dev); |
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dev_set_drvdata(dev, drvdata); |
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retval = kobject_set_name_vargs(&dev->kobj, fmt, args); |
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if (retval) |
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goto error; |
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retval = device_add(dev); |
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if (retval) |
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goto error; |
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return dev; |
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error: |
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put_device(dev); |
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return ERR_PTR(retval); |
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} |
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struct device *cpu_device_create(struct device *parent, void *drvdata, |
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const struct attribute_group **groups, |
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const char *fmt, ...) |
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{ |
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va_list vargs; |
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struct device *dev; |
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va_start(vargs, fmt); |
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dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs); |
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va_end(vargs); |
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return dev; |
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} |
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EXPORT_SYMBOL_GPL(cpu_device_create); |
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#ifdef CONFIG_GENERIC_CPU_AUTOPROBE |
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static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL); |
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#endif |
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static struct attribute *cpu_root_attrs[] = { |
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#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE |
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&dev_attr_probe.attr, |
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&dev_attr_release.attr, |
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#endif |
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&cpu_attrs[0].attr.attr, |
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&cpu_attrs[1].attr.attr, |
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&cpu_attrs[2].attr.attr, |
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&dev_attr_kernel_max.attr, |
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&dev_attr_offline.attr, |
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&dev_attr_isolated.attr, |
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#ifdef CONFIG_NO_HZ_FULL |
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&dev_attr_nohz_full.attr, |
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#endif |
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#ifdef CONFIG_GENERIC_CPU_AUTOPROBE |
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&dev_attr_modalias.attr, |
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#endif |
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NULL |
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}; |
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static const struct attribute_group cpu_root_attr_group = { |
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.attrs = cpu_root_attrs, |
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}; |
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static const struct attribute_group *cpu_root_attr_groups[] = { |
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&cpu_root_attr_group, |
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NULL, |
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}; |
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bool cpu_is_hotpluggable(unsigned cpu) |
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{ |
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struct device *dev = get_cpu_device(cpu); |
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return dev && container_of(dev, struct cpu, dev)->hotpluggable; |
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} |
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EXPORT_SYMBOL_GPL(cpu_is_hotpluggable); |
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#ifdef CONFIG_GENERIC_CPU_DEVICES |
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static DEFINE_PER_CPU(struct cpu, cpu_devices); |
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#endif |
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static void __init cpu_dev_register_generic(void) |
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{ |
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#ifdef CONFIG_GENERIC_CPU_DEVICES |
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int i; |
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for_each_possible_cpu(i) { |
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if (register_cpu(&per_cpu(cpu_devices, i), i)) |
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panic("Failed to register CPU device"); |
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} |
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#endif |
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} |
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#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES |
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|
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ssize_t __weak cpu_show_meltdown(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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ssize_t __weak cpu_show_spectre_v1(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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ssize_t __weak cpu_show_spectre_v2(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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|
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ssize_t __weak cpu_show_spec_store_bypass(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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ssize_t __weak cpu_show_l1tf(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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|
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ssize_t __weak cpu_show_mds(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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|
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ssize_t __weak cpu_show_tsx_async_abort(struct device *dev, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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ssize_t __weak cpu_show_itlb_multihit(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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ssize_t __weak cpu_show_srbds(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sysfs_emit(buf, "Not affected\n"); |
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} |
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static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL); |
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static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL); |
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static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL); |
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static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL); |
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static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL); |
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static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL); |
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static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL); |
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static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL); |
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static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL); |
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|
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static struct attribute *cpu_root_vulnerabilities_attrs[] = { |
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&dev_attr_meltdown.attr, |
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&dev_attr_spectre_v1.attr, |
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&dev_attr_spectre_v2.attr, |
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&dev_attr_spec_store_bypass.attr, |
|
&dev_attr_l1tf.attr, |
|
&dev_attr_mds.attr, |
|
&dev_attr_tsx_async_abort.attr, |
|
&dev_attr_itlb_multihit.attr, |
|
&dev_attr_srbds.attr, |
|
NULL |
|
}; |
|
|
|
static const struct attribute_group cpu_root_vulnerabilities_group = { |
|
.name = "vulnerabilities", |
|
.attrs = cpu_root_vulnerabilities_attrs, |
|
}; |
|
|
|
static void __init cpu_register_vulnerabilities(void) |
|
{ |
|
if (sysfs_create_group(&cpu_subsys.dev_root->kobj, |
|
&cpu_root_vulnerabilities_group)) |
|
pr_err("Unable to register CPU vulnerabilities\n"); |
|
} |
|
|
|
#else |
|
static inline void cpu_register_vulnerabilities(void) { } |
|
#endif |
|
|
|
void __init cpu_dev_init(void) |
|
{ |
|
if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups)) |
|
panic("Failed to register CPU subsystem"); |
|
|
|
cpu_dev_register_generic(); |
|
cpu_register_vulnerabilities(); |
|
}
|
|
|