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![Paul Gortmaker](/assets/img/avatar_default.png)
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0
("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
This removes all the remaining one-off uses of the __cpuinit macros
from all C files in the drivers/* directory.
[1] https://lkml.org/lkml/2013/5/20/589
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
374 lines
9.2 KiB
C
374 lines
9.2 KiB
C
/*
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* CPU subsystem support
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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 "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 __ref 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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cpu_hotplug_driver_lock();
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from_nid = cpu_to_node(cpuid);
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ret = cpu_up(cpuid);
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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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cpu_hotplug_driver_unlock();
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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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int ret;
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cpu_hotplug_driver_lock();
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ret = cpu_down(dev->id);
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cpu_hotplug_driver_unlock();
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return ret;
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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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return arch_cpu_probe(buf, count);
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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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return arch_cpu_release(buf, count);
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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 show_crash_notes(struct device *dev, 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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ssize_t rc;
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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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rc = sprintf(buf, "%Lx\n", addr);
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return rc;
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}
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static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
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static ssize_t show_crash_notes_size(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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ssize_t rc;
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rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
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return rc;
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}
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static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
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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 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 * 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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int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
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buf[n++] = '\n';
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buf[n] = '\0';
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return n;
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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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int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
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return n;
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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 n = 0, len = PAGE_SIZE-2;
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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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n = cpulist_scnprintf(buf, len, 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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if (n && n < len)
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buf[n++] = ',';
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if (nr_cpu_ids == total_cpus-1)
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n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
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else
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n += snprintf(&buf[n], len - n, "%d-%d",
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nr_cpu_ids, total_cpus-1);
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}
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n += snprintf(&buf[n], len - n, "\n");
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return n;
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}
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static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
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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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/*
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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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#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
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cpu->dev.bus->uevent = arch_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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per_cpu(cpu_sys_devices, num) = &cpu->dev;
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if (!error)
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register_cpu_under_node(num, cpu_to_node(num));
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return error;
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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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#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
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static DEVICE_ATTR(modalias, 0444, arch_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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#ifdef CONFIG_ARCH_HAS_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 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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void __init cpu_dev_init(void)
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{
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if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
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panic("Failed to register CPU subsystem");
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cpu_dev_register_generic();
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}
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