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-rw-r--r--drivers/base/cpu.c627
1 files changed, 627 insertions, 0 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
new file mode 100644
index 0000000000..548491de81
--- /dev/null
+++ b/drivers/base/cpu.c
@@ -0,0 +1,627 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CPU subsystem support
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/cpu.h>
+#include <linux/topology.h>
+#include <linux/device.h>
+#include <linux/node.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/percpu.h>
+#include <linux/acpi.h>
+#include <linux/of.h>
+#include <linux/cpufeature.h>
+#include <linux/tick.h>
+#include <linux/pm_qos.h>
+#include <linux/delay.h>
+#include <linux/sched/isolation.h>
+
+#include "base.h"
+
+static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
+
+static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
+{
+ /* ACPI style match is the only one that may succeed. */
+ if (acpi_driver_match_device(dev, drv))
+ return 1;
+
+ return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void change_cpu_under_node(struct cpu *cpu,
+ unsigned int from_nid, unsigned int to_nid)
+{
+ int cpuid = cpu->dev.id;
+ unregister_cpu_under_node(cpuid, from_nid);
+ register_cpu_under_node(cpuid, to_nid);
+ cpu->node_id = to_nid;
+}
+
+static int cpu_subsys_online(struct device *dev)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+ int cpuid = dev->id;
+ int from_nid, to_nid;
+ int ret;
+ int retries = 0;
+
+ from_nid = cpu_to_node(cpuid);
+ if (from_nid == NUMA_NO_NODE)
+ return -ENODEV;
+
+retry:
+ ret = cpu_device_up(dev);
+
+ /*
+ * If -EBUSY is returned, it is likely that hotplug is temporarily
+ * disabled when cpu_hotplug_disable() was called. This condition is
+ * transient. So we retry after waiting for an exponentially
+ * increasing delay up to a total of at least 620ms as some PCI
+ * device initialization can take quite a while.
+ */
+ if (ret == -EBUSY) {
+ retries++;
+ if (retries > 5)
+ return ret;
+ msleep(10 * (1 << retries));
+ goto retry;
+ }
+
+ /*
+ * When hot adding memory to memoryless node and enabling a cpu
+ * on the node, node number of the cpu may internally change.
+ */
+ to_nid = cpu_to_node(cpuid);
+ if (from_nid != to_nid)
+ change_cpu_under_node(cpu, from_nid, to_nid);
+
+ return ret;
+}
+
+static int cpu_subsys_offline(struct device *dev)
+{
+ return cpu_device_down(dev);
+}
+
+void unregister_cpu(struct cpu *cpu)
+{
+ int logical_cpu = cpu->dev.id;
+
+ unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
+
+ device_unregister(&cpu->dev);
+ per_cpu(cpu_sys_devices, logical_cpu) = NULL;
+ return;
+}
+
+#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
+static ssize_t cpu_probe_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ ssize_t cnt;
+ int ret;
+
+ ret = lock_device_hotplug_sysfs();
+ if (ret)
+ return ret;
+
+ cnt = arch_cpu_probe(buf, count);
+
+ unlock_device_hotplug();
+ return cnt;
+}
+
+static ssize_t cpu_release_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ ssize_t cnt;
+ int ret;
+
+ ret = lock_device_hotplug_sysfs();
+ if (ret)
+ return ret;
+
+ cnt = arch_cpu_release(buf, count);
+
+ unlock_device_hotplug();
+ return cnt;
+}
+
+static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
+static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
+#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
+#endif /* CONFIG_HOTPLUG_CPU */
+
+#ifdef CONFIG_KEXEC_CORE
+#include <linux/kexec.h>
+
+static ssize_t crash_notes_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+ unsigned long long addr;
+ int cpunum;
+
+ cpunum = cpu->dev.id;
+
+ /*
+ * Might be reading other cpu's data based on which cpu read thread
+ * has been scheduled. But cpu data (memory) is allocated once during
+ * boot up and this data does not change there after. Hence this
+ * operation should be safe. No locking required.
+ */
+ addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
+
+ return sysfs_emit(buf, "%llx\n", addr);
+}
+static DEVICE_ATTR_ADMIN_RO(crash_notes);
+
+static ssize_t crash_notes_size_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sysfs_emit(buf, "%zu\n", sizeof(note_buf_t));
+}
+static DEVICE_ATTR_ADMIN_RO(crash_notes_size);
+
+static struct attribute *crash_note_cpu_attrs[] = {
+ &dev_attr_crash_notes.attr,
+ &dev_attr_crash_notes_size.attr,
+ NULL
+};
+
+static const struct attribute_group crash_note_cpu_attr_group = {
+ .attrs = crash_note_cpu_attrs,
+};
+#endif
+
+static const struct attribute_group *common_cpu_attr_groups[] = {
+#ifdef CONFIG_KEXEC_CORE
+ &crash_note_cpu_attr_group,
+#endif
+ NULL
+};
+
+static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
+#ifdef CONFIG_KEXEC_CORE
+ &crash_note_cpu_attr_group,
+#endif
+ NULL
+};
+
+/*
+ * Print cpu online, possible, present, and system maps
+ */
+
+struct cpu_attr {
+ struct device_attribute attr;
+ const struct cpumask *const map;
+};
+
+static ssize_t show_cpus_attr(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
+
+ return cpumap_print_to_pagebuf(true, buf, ca->map);
+}
+
+#define _CPU_ATTR(name, map) \
+ { __ATTR(name, 0444, show_cpus_attr, NULL), map }
+
+/* Keep in sync with cpu_subsys_attrs */
+static struct cpu_attr cpu_attrs[] = {
+ _CPU_ATTR(online, &__cpu_online_mask),
+ _CPU_ATTR(possible, &__cpu_possible_mask),
+ _CPU_ATTR(present, &__cpu_present_mask),
+};
+
+/*
+ * Print values for NR_CPUS and offlined cpus
+ */
+static ssize_t print_cpus_kernel_max(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", NR_CPUS - 1);
+}
+static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
+
+/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
+unsigned int total_cpus;
+
+static ssize_t print_cpus_offline(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int len = 0;
+ cpumask_var_t offline;
+
+ /* display offline cpus < nr_cpu_ids */
+ if (!alloc_cpumask_var(&offline, GFP_KERNEL))
+ return -ENOMEM;
+ cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
+ len += sysfs_emit_at(buf, len, "%*pbl", cpumask_pr_args(offline));
+ free_cpumask_var(offline);
+
+ /* display offline cpus >= nr_cpu_ids */
+ if (total_cpus && nr_cpu_ids < total_cpus) {
+ len += sysfs_emit_at(buf, len, ",");
+
+ if (nr_cpu_ids == total_cpus-1)
+ len += sysfs_emit_at(buf, len, "%u", nr_cpu_ids);
+ else
+ len += sysfs_emit_at(buf, len, "%u-%d",
+ nr_cpu_ids, total_cpus - 1);
+ }
+
+ len += sysfs_emit_at(buf, len, "\n");
+
+ return len;
+}
+static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
+
+static ssize_t print_cpus_isolated(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int len;
+ cpumask_var_t isolated;
+
+ if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
+ return -ENOMEM;
+
+ cpumask_andnot(isolated, cpu_possible_mask,
+ housekeeping_cpumask(HK_TYPE_DOMAIN));
+ len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated));
+
+ free_cpumask_var(isolated);
+
+ return len;
+}
+static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
+
+#ifdef CONFIG_NO_HZ_FULL
+static ssize_t print_cpus_nohz_full(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
+}
+static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
+#endif
+
+#ifdef CONFIG_CRASH_HOTPLUG
+static ssize_t crash_hotplug_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sysfs_emit(buf, "%d\n", crash_hotplug_cpu_support());
+}
+static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
+#endif
+
+static void cpu_device_release(struct device *dev)
+{
+ /*
+ * This is an empty function to prevent the driver core from spitting a
+ * warning at us. Yes, I know this is directly opposite of what the
+ * documentation for the driver core and kobjects say, and the author
+ * of this code has already been publically ridiculed for doing
+ * something as foolish as this. However, at this point in time, it is
+ * the only way to handle the issue of statically allocated cpu
+ * devices. The different architectures will have their cpu device
+ * code reworked to properly handle this in the near future, so this
+ * function will then be changed to correctly free up the memory held
+ * by the cpu device.
+ *
+ * Never copy this way of doing things, or you too will be made fun of
+ * on the linux-kernel list, you have been warned.
+ */
+}
+
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+static ssize_t print_cpu_modalias(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ int len = 0;
+ u32 i;
+
+ len += sysfs_emit_at(buf, len,
+ "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
+ CPU_FEATURE_TYPEVAL);
+
+ for (i = 0; i < MAX_CPU_FEATURES; i++)
+ if (cpu_have_feature(i)) {
+ if (len + sizeof(",XXXX\n") >= PAGE_SIZE) {
+ WARN(1, "CPU features overflow page\n");
+ break;
+ }
+ len += sysfs_emit_at(buf, len, ",%04X", i);
+ }
+ len += sysfs_emit_at(buf, len, "\n");
+ return len;
+}
+
+static int cpu_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+ char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+ if (buf) {
+ print_cpu_modalias(NULL, NULL, buf);
+ add_uevent_var(env, "MODALIAS=%s", buf);
+ kfree(buf);
+ }
+ return 0;
+}
+#endif
+
+struct bus_type cpu_subsys = {
+ .name = "cpu",
+ .dev_name = "cpu",
+ .match = cpu_subsys_match,
+#ifdef CONFIG_HOTPLUG_CPU
+ .online = cpu_subsys_online,
+ .offline = cpu_subsys_offline,
+#endif
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+ .uevent = cpu_uevent,
+#endif
+};
+EXPORT_SYMBOL_GPL(cpu_subsys);
+
+/*
+ * register_cpu - Setup a sysfs device for a CPU.
+ * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
+ * sysfs for this CPU.
+ * @num - CPU number to use when creating the device.
+ *
+ * Initialize and register the CPU device.
+ */
+int register_cpu(struct cpu *cpu, int num)
+{
+ int error;
+
+ cpu->node_id = cpu_to_node(num);
+ memset(&cpu->dev, 0x00, sizeof(struct device));
+ cpu->dev.id = num;
+ cpu->dev.bus = &cpu_subsys;
+ cpu->dev.release = cpu_device_release;
+ cpu->dev.offline_disabled = !cpu->hotpluggable;
+ cpu->dev.offline = !cpu_online(num);
+ cpu->dev.of_node = of_get_cpu_node(num, NULL);
+ cpu->dev.groups = common_cpu_attr_groups;
+ if (cpu->hotpluggable)
+ cpu->dev.groups = hotplugable_cpu_attr_groups;
+ error = device_register(&cpu->dev);
+ if (error) {
+ put_device(&cpu->dev);
+ return error;
+ }
+
+ per_cpu(cpu_sys_devices, num) = &cpu->dev;
+ register_cpu_under_node(num, cpu_to_node(num));
+ dev_pm_qos_expose_latency_limit(&cpu->dev,
+ PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
+
+ return 0;
+}
+
+struct device *get_cpu_device(unsigned int cpu)
+{
+ if (cpu < nr_cpu_ids && cpu_possible(cpu))
+ return per_cpu(cpu_sys_devices, cpu);
+ else
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(get_cpu_device);
+
+static void device_create_release(struct device *dev)
+{
+ kfree(dev);
+}
+
+__printf(4, 0)
+static struct device *
+__cpu_device_create(struct device *parent, void *drvdata,
+ const struct attribute_group **groups,
+ const char *fmt, va_list args)
+{
+ struct device *dev = NULL;
+ int retval = -ENOMEM;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ goto error;
+
+ device_initialize(dev);
+ dev->parent = parent;
+ dev->groups = groups;
+ dev->release = device_create_release;
+ device_set_pm_not_required(dev);
+ dev_set_drvdata(dev, drvdata);
+
+ retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
+ if (retval)
+ goto error;
+
+ retval = device_add(dev);
+ if (retval)
+ goto error;
+
+ return dev;
+
+error:
+ put_device(dev);
+ return ERR_PTR(retval);
+}
+
+struct device *cpu_device_create(struct device *parent, void *drvdata,
+ const struct attribute_group **groups,
+ const char *fmt, ...)
+{
+ va_list vargs;
+ struct device *dev;
+
+ va_start(vargs, fmt);
+ dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
+ va_end(vargs);
+ return dev;
+}
+EXPORT_SYMBOL_GPL(cpu_device_create);
+
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
+#endif
+
+static struct attribute *cpu_root_attrs[] = {
+#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
+ &dev_attr_probe.attr,
+ &dev_attr_release.attr,
+#endif
+ &cpu_attrs[0].attr.attr,
+ &cpu_attrs[1].attr.attr,
+ &cpu_attrs[2].attr.attr,
+ &dev_attr_kernel_max.attr,
+ &dev_attr_offline.attr,
+ &dev_attr_isolated.attr,
+#ifdef CONFIG_NO_HZ_FULL
+ &dev_attr_nohz_full.attr,
+#endif
+#ifdef CONFIG_CRASH_HOTPLUG
+ &dev_attr_crash_hotplug.attr,
+#endif
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
+ &dev_attr_modalias.attr,
+#endif
+ NULL
+};
+
+static const struct attribute_group cpu_root_attr_group = {
+ .attrs = cpu_root_attrs,
+};
+
+static const struct attribute_group *cpu_root_attr_groups[] = {
+ &cpu_root_attr_group,
+ NULL,
+};
+
+bool cpu_is_hotpluggable(unsigned int cpu)
+{
+ struct device *dev = get_cpu_device(cpu);
+ return dev && container_of(dev, struct cpu, dev)->hotpluggable
+ && tick_nohz_cpu_hotpluggable(cpu);
+}
+EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
+
+#ifdef CONFIG_GENERIC_CPU_DEVICES
+static DEFINE_PER_CPU(struct cpu, cpu_devices);
+#endif
+
+static void __init cpu_dev_register_generic(void)
+{
+#ifdef CONFIG_GENERIC_CPU_DEVICES
+ int i;
+
+ for_each_possible_cpu(i) {
+ if (register_cpu(&per_cpu(cpu_devices, i), i))
+ panic("Failed to register CPU device");
+ }
+#endif
+}
+
+#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
+static ssize_t cpu_show_not_affected(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "Not affected\n");
+}
+
+#define CPU_SHOW_VULN_FALLBACK(func) \
+ ssize_t cpu_show_##func(struct device *, \
+ struct device_attribute *, char *) \
+ __attribute__((weak, alias("cpu_show_not_affected")))
+
+CPU_SHOW_VULN_FALLBACK(meltdown);
+CPU_SHOW_VULN_FALLBACK(spectre_v1);
+CPU_SHOW_VULN_FALLBACK(spectre_v2);
+CPU_SHOW_VULN_FALLBACK(spec_store_bypass);
+CPU_SHOW_VULN_FALLBACK(l1tf);
+CPU_SHOW_VULN_FALLBACK(mds);
+CPU_SHOW_VULN_FALLBACK(tsx_async_abort);
+CPU_SHOW_VULN_FALLBACK(itlb_multihit);
+CPU_SHOW_VULN_FALLBACK(srbds);
+CPU_SHOW_VULN_FALLBACK(mmio_stale_data);
+CPU_SHOW_VULN_FALLBACK(retbleed);
+CPU_SHOW_VULN_FALLBACK(spec_rstack_overflow);
+CPU_SHOW_VULN_FALLBACK(gds);
+
+static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
+static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
+static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
+static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
+static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
+static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
+static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
+static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
+static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
+static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
+static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
+static DEVICE_ATTR(spec_rstack_overflow, 0444, cpu_show_spec_rstack_overflow, NULL);
+static DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);
+
+static struct attribute *cpu_root_vulnerabilities_attrs[] = {
+ &dev_attr_meltdown.attr,
+ &dev_attr_spectre_v1.attr,
+ &dev_attr_spectre_v2.attr,
+ &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,
+ &dev_attr_mmio_stale_data.attr,
+ &dev_attr_retbleed.attr,
+ &dev_attr_spec_rstack_overflow.attr,
+ &dev_attr_gather_data_sampling.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)
+{
+ struct device *dev = bus_get_dev_root(&cpu_subsys);
+
+ if (dev) {
+ if (sysfs_create_group(&dev->kobj, &cpu_root_vulnerabilities_group))
+ pr_err("Unable to register CPU vulnerabilities\n");
+ put_device(dev);
+ }
+}
+
+#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();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 11:57:00 +0000