Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 696 insertions, 0 deletions

diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
new file mode 100644
index 000000000..69e52fed4
--- /dev/null
+++ b/drivers/base/cpu.c
@@ -0,0 +1,696 @@
+// 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, const 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;
+
+	set_cpu_enabled(logical_cpu, false);
+	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_CRASH_DUMP
+#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_CRASH_DUMP
+	&crash_note_cpu_attr_group,
+#endif
+	NULL
+};
+
+static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
+#ifdef CONFIG_CRASH_DUMP
+	&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 sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(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_enabled(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(cpu_enabled_mask));
+}
+static DEVICE_ATTR(enabled, 0444, print_cpus_enabled, 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_BOOT));
+	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);
+
+static ssize_t housekeeping_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	const struct cpumask *hk_mask;
+
+	hk_mask = housekeeping_cpumask(HK_TYPE_KERNEL_NOISE);
+
+	if (housekeeping_enabled(HK_TYPE_KERNEL_NOISE))
+		return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(hk_mask));
+	return sysfs_emit(buf, "\n");
+}
+static DEVICE_ATTR_RO(housekeeping);
+
+#ifdef CONFIG_NO_HZ_FULL
+static ssize_t nohz_full_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	if (cpumask_available(tick_nohz_full_mask))
+		return sysfs_emit(buf, "%*pbl\n",
+				  cpumask_pr_args(tick_nohz_full_mask));
+	return sysfs_emit(buf, "\n");
+}
+static DEVICE_ATTR_RO(nohz_full);
+#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_check_hotplug_support());
+}
+static DEVICE_ATTR_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 publicly 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
+
+const 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;
+	dev_assign_offline_disabled(&cpu->dev, !cpu->hotpluggable);
+	dev_assign_offline(&cpu->dev, !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);
+	set_cpu_enabled(num, true);
+
+	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_obj(*dev);
+	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_enabled.attr,
+	&dev_attr_isolated.attr,
+	&dev_attr_housekeeping.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
+DEFINE_PER_CPU(struct cpu, cpu_devices);
+
+bool __weak arch_cpu_is_hotpluggable(int cpu)
+{
+	return false;
+}
+
+int __weak arch_register_cpu(int cpu)
+{
+	struct cpu *c = &per_cpu(cpu_devices, cpu);
+
+	c->hotpluggable = arch_cpu_is_hotpluggable(cpu);
+
+	return register_cpu(c, cpu);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void __weak arch_unregister_cpu(int num)
+{
+	unregister_cpu(&per_cpu(cpu_devices, num));
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+#endif /* CONFIG_GENERIC_CPU_DEVICES */
+
+static void __init cpu_dev_register_generic(void)
+{
+	int i, ret;
+
+	if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES))
+		return;
+
+	for_each_present_cpu(i) {
+		ret = arch_register_cpu(i);
+		if (ret && ret != -EPROBE_DEFER)
+			pr_warn("register_cpu %d failed (%d)\n", i, ret);
+	}
+}
+
+#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);
+CPU_SHOW_VULN_FALLBACK(reg_file_data_sampling);
+CPU_SHOW_VULN_FALLBACK(ghostwrite);
+CPU_SHOW_VULN_FALLBACK(old_microcode);
+CPU_SHOW_VULN_FALLBACK(indirect_target_selection);
+CPU_SHOW_VULN_FALLBACK(tsa);
+CPU_SHOW_VULN_FALLBACK(vmscape);
+
+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 DEVICE_ATTR(reg_file_data_sampling, 0444, cpu_show_reg_file_data_sampling, NULL);
+static DEVICE_ATTR(ghostwrite, 0444, cpu_show_ghostwrite, NULL);
+static DEVICE_ATTR(old_microcode, 0444, cpu_show_old_microcode, NULL);
+static DEVICE_ATTR(indirect_target_selection, 0444, cpu_show_indirect_target_selection, NULL);
+static DEVICE_ATTR(tsa, 0444, cpu_show_tsa, NULL);
+static DEVICE_ATTR(vmscape, 0444, cpu_show_vmscape, 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,
+	&dev_attr_reg_file_data_sampling.attr,
+	&dev_attr_ghostwrite.attr,
+	&dev_attr_old_microcode.attr,
+	&dev_attr_indirect_target_selection.attr,
+	&dev_attr_tsa.attr,
+	&dev_attr_vmscape.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();
+}