![Kay Sievers](/assets/img/avatar_default.png)
This moves the 'cpu sysdev_class' over to a regular 'cpu' subsystem and converts the devices to regular devices. The sysdev drivers are implemented as subsystem interfaces now. After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Userspace relies on events and generic sysfs subsystem infrastructure from sysdev devices, which are made available with this conversion. Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Borislav Petkov <bp@amd64.org> Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Cc: Len Brown <lenb@kernel.org> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Dave Jones <davej@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
283 lines
6.6 KiB
C
283 lines
6.6 KiB
C
/*
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* CPU subsystem support
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*/
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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 "base.h"
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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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};
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EXPORT_SYMBOL_GPL(cpu_subsys);
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static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
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#ifdef CONFIG_HOTPLUG_CPU
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static ssize_t show_online(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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return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id));
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}
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static ssize_t __ref store_online(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct cpu *cpu = container_of(dev, struct cpu, dev);
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ssize_t ret;
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cpu_hotplug_driver_lock();
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switch (buf[0]) {
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case '0':
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ret = cpu_down(cpu->dev.id);
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if (!ret)
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kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
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break;
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case '1':
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ret = cpu_up(cpu->dev.id);
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if (!ret)
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kobject_uevent(&dev->kobj, KOBJ_ONLINE);
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break;
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default:
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ret = -EINVAL;
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}
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cpu_hotplug_driver_unlock();
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if (ret >= 0)
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ret = count;
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return ret;
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}
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static DEVICE_ATTR(online, 0644, show_online, store_online);
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static void __cpuinit register_cpu_control(struct cpu *cpu)
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{
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device_create_file(&cpu->dev, &dev_attr_online);
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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_remove_file(&cpu->dev, &dev_attr_online);
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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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#else /* ... !CONFIG_HOTPLUG_CPU */
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static inline void register_cpu_control(struct cpu *cpu)
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{
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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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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#endif
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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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/*
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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 __cpuinit 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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cpu->dev.id = num;
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cpu->dev.bus = &cpu_subsys;
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error = device_register(&cpu->dev);
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if (!error && cpu->hotpluggable)
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register_cpu_control(cpu);
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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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#ifdef CONFIG_KEXEC
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if (!error)
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error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
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#endif
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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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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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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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int __init cpu_dev_init(void)
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{
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int err;
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err = subsys_system_register(&cpu_subsys, cpu_root_attr_groups);
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if (err)
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return err;
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#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
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err = sched_create_sysfs_power_savings_entries(cpu_subsys.dev_root);
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#endif
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return err;
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}
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