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, 1222 insertions, 0 deletions

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
new file mode 100644
index 000000000..84a77ffa3
--- /dev/null
+++ b/drivers/base/swnode.c
@@ -0,0 +1,1222 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Software nodes for the firmware node framework.
+ *
+ * Copyright (C) 2018, Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ */
+
+#include <linux/container_of.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/idr.h>
+#include <linux/init.h>
+#include <linux/kobject.h>
+#include <linux/kstrtox.h>
+#include <linux/list.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+#include "base.h"
+
+struct swnode {
+	struct kobject kobj;
+	struct fwnode_handle fwnode;
+	const struct software_node *node;
+	int id;
+
+	/* hierarchy */
+	struct ida child_ids;
+	struct list_head entry;
+	struct list_head children;
+	struct swnode *parent;
+
+	unsigned int allocated:1;
+	unsigned int managed:1;
+};
+
+static DEFINE_IDA(swnode_root_ids);
+static struct kset *swnode_kset;
+
+#define kobj_to_swnode(_kobj_) container_of(_kobj_, struct swnode, kobj)
+
+static const struct fwnode_operations software_node_ops;
+
+bool is_software_node(const struct fwnode_handle *fwnode)
+{
+	return !IS_ERR_OR_NULL(fwnode) && fwnode->ops == &software_node_ops;
+}
+EXPORT_SYMBOL_GPL(is_software_node);
+
+#define to_swnode(__fwnode)						\
+	({								\
+		typeof(__fwnode) __to_swnode_fwnode = __fwnode;		\
+									\
+		is_software_node(__to_swnode_fwnode) ?			\
+			container_of(__to_swnode_fwnode,		\
+				     struct swnode, fwnode) : NULL;	\
+	})
+
+static inline struct swnode *dev_to_swnode(struct device *dev)
+{
+	struct fwnode_handle *fwnode = dev_fwnode(dev);
+
+	if (!fwnode)
+		return NULL;
+
+	if (!is_software_node(fwnode))
+		fwnode = fwnode->secondary;
+
+	return to_swnode(fwnode);
+}
+
+static struct swnode *
+software_node_to_swnode(const struct software_node *node)
+{
+	struct swnode *swnode = NULL;
+	struct kobject *k;
+
+	if (!node)
+		return NULL;
+
+	spin_lock(&swnode_kset->list_lock);
+
+	list_for_each_entry(k, &swnode_kset->list, entry) {
+		swnode = kobj_to_swnode(k);
+		if (swnode->node == node)
+			break;
+		swnode = NULL;
+	}
+
+	spin_unlock(&swnode_kset->list_lock);
+
+	return swnode;
+}
+
+const struct software_node *to_software_node(const struct fwnode_handle *fwnode)
+{
+	const struct swnode *swnode = to_swnode(fwnode);
+
+	return swnode ? swnode->node : NULL;
+}
+EXPORT_SYMBOL_GPL(to_software_node);
+
+struct fwnode_handle *software_node_fwnode(const struct software_node *node)
+{
+	struct swnode *swnode = software_node_to_swnode(node);
+
+	return swnode ? &swnode->fwnode : NULL;
+}
+EXPORT_SYMBOL_GPL(software_node_fwnode);
+
+/* -------------------------------------------------------------------------- */
+/* property_entry processing */
+
+static const struct property_entry *
+property_entry_get(const struct property_entry *prop, const char *name)
+{
+	if (!prop)
+		return NULL;
+
+	for (; prop->name; prop++)
+		if (!strcmp(name, prop->name))
+			return prop;
+
+	return NULL;
+}
+
+static const void *property_get_pointer(const struct property_entry *prop)
+{
+	if (!prop->length)
+		return NULL;
+
+	return prop->is_inline ? &prop->value : prop->pointer;
+}
+
+static const void *property_entry_find(const struct property_entry *props,
+				       const char *propname, size_t length)
+{
+	const struct property_entry *prop;
+	const void *pointer;
+
+	prop = property_entry_get(props, propname);
+	if (!prop)
+		return ERR_PTR(-EINVAL);
+	pointer = property_get_pointer(prop);
+	if (!pointer)
+		return ERR_PTR(-ENODATA);
+	if (length > prop->length)
+		return ERR_PTR(-EOVERFLOW);
+	return pointer;
+}
+
+static int
+property_entry_count_elems_of_size(const struct property_entry *props,
+				   const char *propname, size_t length)
+{
+	const struct property_entry *prop;
+
+	prop = property_entry_get(props, propname);
+	if (!prop)
+		return -EINVAL;
+
+	return prop->length / length;
+}
+
+static int property_entry_read_int_array(const struct property_entry *props,
+					 const char *name,
+					 unsigned int elem_size, void *val,
+					 size_t nval)
+{
+	const void *pointer;
+	size_t length;
+
+	if (!val)
+		return property_entry_count_elems_of_size(props, name,
+							  elem_size);
+
+	if (!is_power_of_2(elem_size) || elem_size > sizeof(u64))
+		return -ENXIO;
+
+	length = nval * elem_size;
+
+	pointer = property_entry_find(props, name, length);
+	if (IS_ERR(pointer))
+		return PTR_ERR(pointer);
+
+	memcpy(val, pointer, length);
+	return 0;
+}
+
+static int property_entry_read_string_array(const struct property_entry *props,
+					    const char *propname,
+					    const char **strings, size_t nval)
+{
+	const void *pointer;
+	size_t length;
+	int array_len;
+
+	/* Find out the array length. */
+	array_len = property_entry_count_elems_of_size(props, propname,
+						       sizeof(const char *));
+	if (array_len < 0)
+		return array_len;
+
+	/* Return how many there are if strings is NULL. */
+	if (!strings)
+		return array_len;
+
+	array_len = min_t(size_t, nval, array_len);
+	length = array_len * sizeof(*strings);
+
+	pointer = property_entry_find(props, propname, length);
+	if (IS_ERR(pointer))
+		return PTR_ERR(pointer);
+
+	memcpy(strings, pointer, length);
+
+	return array_len;
+}
+
+static void property_entry_free_data(const struct property_entry *p)
+{
+	const char * const *src_str;
+	size_t i, nval;
+
+	if (p->type == DEV_PROP_STRING) {
+		src_str = property_get_pointer(p);
+		nval = p->length / sizeof(*src_str);
+		for (i = 0; i < nval; i++)
+			kfree(src_str[i]);
+	}
+
+	if (!p->is_inline)
+		kfree(p->pointer);
+
+	kfree(p->name);
+}
+
+static bool property_copy_string_array(const char **dst_ptr,
+				       const char * const *src_ptr,
+				       size_t nval)
+{
+	int i;
+
+	for (i = 0; i < nval; i++) {
+		dst_ptr[i] = kstrdup(src_ptr[i], GFP_KERNEL);
+		if (!dst_ptr[i] && src_ptr[i]) {
+			while (--i >= 0)
+				kfree(dst_ptr[i]);
+			return false;
+		}
+	}
+
+	return true;
+}
+
+static int property_entry_copy_data(struct property_entry *dst,
+				    const struct property_entry *src)
+{
+	const void *pointer = property_get_pointer(src);
+	void *dst_ptr;
+	size_t nval;
+
+	/*
+	 * Properties with no data should not be marked as stored
+	 * out of line.
+	 */
+	if (!src->is_inline && !src->length)
+		return -ENODATA;
+
+	/*
+	 * Reference properties are never stored inline as
+	 * they are too big.
+	 */
+	if (src->type == DEV_PROP_REF && src->is_inline)
+		return -EINVAL;
+
+	if (src->length <= sizeof(dst->value)) {
+		dst_ptr = &dst->value;
+		dst->is_inline = true;
+	} else {
+		dst_ptr = kmalloc(src->length, GFP_KERNEL);
+		if (!dst_ptr)
+			return -ENOMEM;
+		dst->pointer = dst_ptr;
+	}
+
+	if (src->type == DEV_PROP_STRING) {
+		nval = src->length / sizeof(const char *);
+		if (!property_copy_string_array(dst_ptr, pointer, nval)) {
+			if (!dst->is_inline)
+				kfree(dst->pointer);
+			return -ENOMEM;
+		}
+	} else {
+		memcpy(dst_ptr, pointer, src->length);
+	}
+
+	dst->length = src->length;
+	dst->type = src->type;
+	dst->name = kstrdup(src->name, GFP_KERNEL);
+	if (!dst->name) {
+		property_entry_free_data(dst);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/**
+ * property_entries_dup - duplicate array of properties
+ * @properties: array of properties to copy
+ *
+ * This function creates a deep copy of the given NULL-terminated array
+ * of property entries.
+ */
+struct property_entry *
+property_entries_dup(const struct property_entry *properties)
+{
+	struct property_entry *p;
+	int i, n = 0;
+	int ret;
+
+	if (!properties)
+		return NULL;
+
+	while (properties[n].name)
+		n++;
+
+	p = kzalloc_objs(*p, n + 1);
+	if (!p)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < n; i++) {
+		ret = property_entry_copy_data(&p[i], &properties[i]);
+		if (ret) {
+			while (--i >= 0)
+				property_entry_free_data(&p[i]);
+			kfree(p);
+			return ERR_PTR(ret);
+		}
+	}
+
+	return p;
+}
+EXPORT_SYMBOL_GPL(property_entries_dup);
+
+/**
+ * property_entries_free - free previously allocated array of properties
+ * @properties: array of properties to destroy
+ *
+ * This function frees given NULL-terminated array of property entries,
+ * along with their data.
+ */
+void property_entries_free(const struct property_entry *properties)
+{
+	const struct property_entry *p;
+
+	if (!properties)
+		return;
+
+	for (p = properties; p->name; p++)
+		property_entry_free_data(p);
+
+	kfree(properties);
+}
+EXPORT_SYMBOL_GPL(property_entries_free);
+
+/* -------------------------------------------------------------------------- */
+/* fwnode operations */
+
+static struct swnode *swnode_get(struct swnode *swnode)
+{
+	kobject_get(&swnode->kobj);
+
+	return swnode;
+}
+
+static void swnode_put(struct swnode *swnode)
+{
+	kobject_put(&swnode->kobj);
+}
+
+static struct fwnode_handle *software_node_get(struct fwnode_handle *fwnode)
+{
+	struct swnode *swnode = swnode_get(to_swnode(fwnode));
+
+	return &swnode->fwnode;
+}
+
+static void software_node_put(struct fwnode_handle *fwnode)
+{
+	swnode_put(to_swnode(fwnode));
+}
+
+static bool software_node_property_present(const struct fwnode_handle *fwnode,
+					   const char *propname)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+
+	return !!property_entry_get(swnode->node->properties, propname);
+}
+
+static int software_node_read_int_array(const struct fwnode_handle *fwnode,
+					const char *propname,
+					unsigned int elem_size, void *val,
+					size_t nval)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+
+	return property_entry_read_int_array(swnode->node->properties, propname,
+					     elem_size, val, nval);
+}
+
+static int software_node_read_string_array(const struct fwnode_handle *fwnode,
+					   const char *propname,
+					   const char **val, size_t nval)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+
+	return property_entry_read_string_array(swnode->node->properties,
+						propname, val, nval);
+}
+
+static const char *
+software_node_get_name(const struct fwnode_handle *fwnode)
+{
+	const struct swnode *swnode = to_swnode(fwnode);
+
+	return kobject_name(&swnode->kobj);
+}
+
+static const char *
+software_node_get_name_prefix(const struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *parent;
+	const char *prefix;
+
+	parent = fwnode_get_parent(fwnode);
+	if (!parent)
+		return "";
+
+	/* Figure out the prefix from the parents. */
+	while (is_software_node(parent))
+		parent = fwnode_get_next_parent(parent);
+
+	prefix = fwnode_get_name_prefix(parent);
+	fwnode_handle_put(parent);
+
+	/* Guess something if prefix was NULL. */
+	return prefix ?: "/";
+}
+
+static struct fwnode_handle *
+software_node_get_parent(const struct fwnode_handle *fwnode)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+
+	if (!swnode || !swnode->parent)
+		return NULL;
+
+	return fwnode_handle_get(&swnode->parent->fwnode);
+}
+
+static struct fwnode_handle *
+software_node_get_next_child(const struct fwnode_handle *fwnode,
+			     struct fwnode_handle *child)
+{
+	struct swnode *p = to_swnode(fwnode);
+	struct swnode *c = to_swnode(child);
+
+	if (!p || list_empty(&p->children) ||
+	    (c && list_is_last(&c->entry, &p->children))) {
+		fwnode_handle_put(child);
+		return NULL;
+	}
+
+	if (c)
+		c = list_next_entry(c, entry);
+	else
+		c = list_first_entry(&p->children, struct swnode, entry);
+
+	fwnode_handle_put(child);
+	return fwnode_handle_get(&c->fwnode);
+}
+
+static struct fwnode_handle *
+software_node_get_named_child_node(const struct fwnode_handle *fwnode,
+				   const char *childname)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+	struct swnode *child;
+
+	if (!swnode || list_empty(&swnode->children))
+		return NULL;
+
+	list_for_each_entry(child, &swnode->children, entry) {
+		if (!strcmp(childname, kobject_name(&child->kobj))) {
+			swnode_get(child);
+			return &child->fwnode;
+		}
+	}
+	return NULL;
+}
+
+static int
+software_node_get_reference_args(const struct fwnode_handle *fwnode,
+				 const char *propname, const char *nargs_prop,
+				 unsigned int nargs, unsigned int index,
+				 struct fwnode_reference_args *args)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+	const struct software_node_ref_args *ref_array;
+	const struct software_node_ref_args *ref;
+	const struct property_entry *prop;
+	struct fwnode_handle *refnode;
+	u32 nargs_prop_val;
+	int error;
+	int i;
+
+	prop = property_entry_get(swnode->node->properties, propname);
+	if (!prop)
+		return -ENOENT;
+
+	if (prop->type != DEV_PROP_REF)
+		return -EINVAL;
+
+	/*
+	 * We expect that references are never stored inline, even
+	 * single ones, as they are too big.
+	 */
+	if (prop->is_inline)
+		return -EINVAL;
+
+	if (index >= prop->length / sizeof(*ref))
+		return -ENOENT;
+
+	ref_array = prop->pointer;
+	ref = &ref_array[index];
+
+	/*
+	 * A software node can reference other software nodes or firmware
+	 * nodes (which are the abstraction layer sitting on top of them).
+	 * This is done to ensure we can create references to static software
+	 * nodes before they're registered with the firmware node framework.
+	 * At the time the reference is being resolved, we expect the swnodes
+	 * in question to already have been registered and to be backed by
+	 * a firmware node. This is why we use the fwnode API below to read the
+	 * relevant properties and bump the reference count.
+	 */
+
+	if (ref->swnode)
+		refnode = software_node_fwnode(ref->swnode);
+	else if (ref->fwnode)
+		refnode = ref->fwnode;
+	else
+		return -EINVAL;
+
+	if (!refnode)
+		return -ENOTCONN;
+
+	if (nargs_prop) {
+		error = fwnode_property_read_u32(refnode, nargs_prop, &nargs_prop_val);
+		if (error)
+			return error;
+
+		nargs = nargs_prop_val;
+	}
+
+	if (nargs > NR_FWNODE_REFERENCE_ARGS)
+		return -EINVAL;
+
+	if (!args)
+		return 0;
+
+	args->fwnode = fwnode_handle_get(refnode);
+	args->nargs = nargs;
+
+	for (i = 0; i < nargs; i++)
+		args->args[i] = ref->args[i];
+
+	return 0;
+}
+
+static struct fwnode_handle *
+swnode_graph_find_next_port(const struct fwnode_handle *parent,
+			    struct fwnode_handle *port)
+{
+	struct fwnode_handle *old = port;
+
+	while ((port = software_node_get_next_child(parent, old))) {
+		/*
+		 * fwnode ports have naming style "port@", so we search for any
+		 * children that follow that convention.
+		 */
+		if (!strncmp(to_swnode(port)->node->name, "port@",
+			     strlen("port@")))
+			return port;
+		old = port;
+	}
+
+	return NULL;
+}
+
+static struct fwnode_handle *
+software_node_graph_get_next_endpoint(const struct fwnode_handle *fwnode,
+				      struct fwnode_handle *endpoint)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+	struct fwnode_handle *parent;
+	struct fwnode_handle *port;
+
+	if (!swnode)
+		return NULL;
+
+	if (endpoint) {
+		port = software_node_get_parent(endpoint);
+		parent = software_node_get_parent(port);
+	} else {
+		parent = software_node_get_named_child_node(fwnode, "ports");
+		if (!parent)
+			parent = software_node_get(&swnode->fwnode);
+
+		port = swnode_graph_find_next_port(parent, NULL);
+	}
+
+	for (; port; port = swnode_graph_find_next_port(parent, port)) {
+		endpoint = software_node_get_next_child(port, endpoint);
+		if (endpoint) {
+			fwnode_handle_put(port);
+			break;
+		}
+	}
+
+	fwnode_handle_put(parent);
+
+	return endpoint;
+}
+
+static struct fwnode_handle *
+software_node_graph_get_remote_endpoint(const struct fwnode_handle *fwnode)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+	const struct software_node_ref_args *ref;
+	const struct property_entry *prop;
+
+	if (!swnode)
+		return NULL;
+
+	prop = property_entry_get(swnode->node->properties, "remote-endpoint");
+	if (!prop || prop->type != DEV_PROP_REF || prop->is_inline)
+		return NULL;
+
+	ref = prop->pointer;
+
+	if (!ref->swnode)
+		return NULL;
+
+	return software_node_get(software_node_fwnode(ref->swnode));
+}
+
+static struct fwnode_handle *
+software_node_graph_get_port_parent(struct fwnode_handle *fwnode)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+
+	swnode = swnode->parent;
+	if (swnode && !strcmp(swnode->node->name, "ports"))
+		swnode = swnode->parent;
+
+	return swnode ? software_node_get(&swnode->fwnode) : NULL;
+}
+
+static int
+software_node_graph_parse_endpoint(const struct fwnode_handle *fwnode,
+				   struct fwnode_endpoint *endpoint)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+	const char *parent_name = swnode->parent->node->name;
+	int ret;
+
+	if (strlen("port@") >= strlen(parent_name) ||
+	    strncmp(parent_name, "port@", strlen("port@")))
+		return -EINVAL;
+
+	/* Ports have naming style "port@n", we need to select the n */
+	ret = kstrtou32(parent_name + strlen("port@"), 10, &endpoint->port);
+	if (ret)
+		return ret;
+
+	endpoint->id = swnode->id;
+	endpoint->local_fwnode = fwnode;
+
+	return 0;
+}
+
+static int software_node_add_links(struct fwnode_handle *fwnode)
+{
+	const struct software_node_ref_args *ref, *ref_array;
+	struct swnode *swnode = to_swnode(fwnode);
+	const struct property_entry *prop;
+	struct fwnode_handle *refnode;
+	unsigned int count;
+
+	if (!swnode || !swnode->node->properties)
+		return 0;
+
+	/*
+	 * Unlike Device Tree, where phandles appear in many non-supplier
+	 * contexts and a curated allowlist is required, a software node only
+	 * carries a DEV_PROP_REF property when the author explicitly describes
+	 * a reference to another node. Every such reference is therefore an
+	 * intentional supplier dependency, so we create fwnode links for all
+	 * of them.
+	 */
+	for (prop = swnode->node->properties; prop->name; prop++) {
+		if (prop->type != DEV_PROP_REF || prop->is_inline)
+			continue;
+
+		/*
+		 * TODO: Graph "remote-endpoint" references go both ways
+		 * between endpoint child nodes and would create endpoint
+		 * cycles. Let's leave it out for now until we have potential
+		 * users.
+		 */
+		if (!strcmp(prop->name, "remote-endpoint"))
+			continue;
+
+		ref_array = prop->pointer;
+		count = prop->length / sizeof(*ref_array);
+
+		for (unsigned int i = 0; i < count; i++) {
+			ref = &ref_array[i];
+
+			if (ref->swnode)
+				refnode = software_node_fwnode(ref->swnode);
+			else if (ref->fwnode)
+				refnode = ref->fwnode;
+			else
+				continue;
+
+			/* Supplier not registered yet, or self-reference. */
+			if (!refnode || refnode == &swnode->fwnode)
+				continue;
+
+			fwnode_link_add(&swnode->fwnode, refnode, 0);
+		}
+	}
+
+	return 0;
+}
+
+static const struct fwnode_operations software_node_ops = {
+	.get = software_node_get,
+	.put = software_node_put,
+	.property_present = software_node_property_present,
+	.property_read_bool = software_node_property_present,
+	.property_read_int_array = software_node_read_int_array,
+	.property_read_string_array = software_node_read_string_array,
+	.get_name = software_node_get_name,
+	.get_name_prefix = software_node_get_name_prefix,
+	.get_parent = software_node_get_parent,
+	.get_next_child_node = software_node_get_next_child,
+	.get_named_child_node = software_node_get_named_child_node,
+	.get_reference_args = software_node_get_reference_args,
+	.graph_get_next_endpoint = software_node_graph_get_next_endpoint,
+	.graph_get_remote_endpoint = software_node_graph_get_remote_endpoint,
+	.graph_get_port_parent = software_node_graph_get_port_parent,
+	.graph_parse_endpoint = software_node_graph_parse_endpoint,
+	.add_links = software_node_add_links,
+};
+
+/* -------------------------------------------------------------------------- */
+
+/**
+ * software_node_find_by_name - Find software node by name
+ * @parent: Parent of the software node
+ * @name: Name of the software node
+ *
+ * The function will find a node that is child of @parent and that is named
+ * @name. If no node is found, the function returns NULL.
+ *
+ * NOTE: you will need to drop the reference with fwnode_handle_put() after use.
+ */
+const struct software_node *
+software_node_find_by_name(const struct software_node *parent, const char *name)
+{
+	struct swnode *swnode = NULL;
+	struct kobject *k;
+
+	if (!name)
+		return NULL;
+
+	spin_lock(&swnode_kset->list_lock);
+
+	list_for_each_entry(k, &swnode_kset->list, entry) {
+		swnode = kobj_to_swnode(k);
+		if (parent == swnode->node->parent && swnode->node->name &&
+		    !strcmp(name, swnode->node->name)) {
+			swnode_get(swnode);
+			break;
+		}
+		swnode = NULL;
+	}
+
+	spin_unlock(&swnode_kset->list_lock);
+
+	return swnode ? swnode->node : NULL;
+}
+EXPORT_SYMBOL_GPL(software_node_find_by_name);
+
+static struct software_node *software_node_alloc(const struct property_entry *properties)
+{
+	struct property_entry *props;
+	struct software_node *node;
+
+	props = property_entries_dup(properties);
+	if (IS_ERR(props))
+		return ERR_CAST(props);
+
+	node = kzalloc_obj(*node);
+	if (!node) {
+		property_entries_free(props);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	node->properties = props;
+
+	return node;
+}
+
+static void software_node_free(const struct software_node *node)
+{
+	property_entries_free(node->properties);
+	kfree(node);
+}
+
+static void software_node_release(struct kobject *kobj)
+{
+	struct swnode *swnode = kobj_to_swnode(kobj);
+
+	fwnode_links_purge(&swnode->fwnode);
+
+	if (swnode->parent) {
+		ida_free(&swnode->parent->child_ids, swnode->id);
+		list_del(&swnode->entry);
+	} else {
+		ida_free(&swnode_root_ids, swnode->id);
+	}
+
+	if (swnode->allocated)
+		software_node_free(swnode->node);
+
+	ida_destroy(&swnode->child_ids);
+	kfree(swnode);
+}
+
+static const struct kobj_type software_node_type = {
+	.release = software_node_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+};
+
+static struct fwnode_handle *
+swnode_register(const struct software_node *node, struct swnode *parent,
+		unsigned int allocated)
+{
+	struct swnode *swnode;
+	int ret;
+
+	swnode = kzalloc_obj(*swnode);
+	if (!swnode)
+		return ERR_PTR(-ENOMEM);
+
+	ret = ida_alloc(parent ? &parent->child_ids : &swnode_root_ids,
+			GFP_KERNEL);
+	if (ret < 0) {
+		kfree(swnode);
+		return ERR_PTR(ret);
+	}
+
+	swnode->id = ret;
+	swnode->node = node;
+	swnode->parent = parent;
+	swnode->kobj.kset = swnode_kset;
+	fwnode_init(&swnode->fwnode, &software_node_ops);
+
+	ida_init(&swnode->child_ids);
+	INIT_LIST_HEAD(&swnode->entry);
+	INIT_LIST_HEAD(&swnode->children);
+
+	if (node->name)
+		ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
+					   parent ? &parent->kobj : NULL,
+					   "%s", node->name);
+	else
+		ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
+					   parent ? &parent->kobj : NULL,
+					   "node%d", swnode->id);
+	if (ret) {
+		swnode_put(swnode);
+		return ERR_PTR(ret);
+	}
+
+	/*
+	 * Assign the flag only in the successful case, so
+	 * the above swnode_put() won't mess up with properties.
+	 */
+	swnode->allocated = allocated;
+
+	if (parent)
+		list_add_tail(&swnode->entry, &parent->children);
+
+	kobject_uevent(&swnode->kobj, KOBJ_ADD);
+	return &swnode->fwnode;
+}
+
+/**
+ * software_node_register_node_group - Register a group of software nodes
+ * @node_group: NULL terminated array of software node pointers to be registered
+ *
+ * Register multiple software nodes at once. If any node in the array
+ * has its .parent pointer set (which can only be to another software_node),
+ * then its parent **must** have been registered before it is; either outside
+ * of this function or by ordering the array such that parent comes before
+ * child.
+ */
+int software_node_register_node_group(const struct software_node * const *node_group)
+{
+	unsigned int i;
+	int ret;
+
+	if (!node_group)
+		return 0;
+
+	for (i = 0; node_group[i]; i++) {
+		ret = software_node_register(node_group[i]);
+		if (ret) {
+			software_node_unregister_node_group(node_group);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(software_node_register_node_group);
+
+/**
+ * software_node_unregister_node_group - Unregister a group of software nodes
+ * @node_group: NULL terminated array of software node pointers to be unregistered
+ *
+ * Unregister multiple software nodes at once. If parent pointers are set up
+ * in any of the software nodes then the array **must** be ordered such that
+ * parents come before their children.
+ *
+ * NOTE: If you are uncertain whether the array is ordered such that
+ * parents will be unregistered before their children, it is wiser to
+ * remove the nodes individually, in the correct order (child before
+ * parent).
+ */
+void software_node_unregister_node_group(const struct software_node * const *node_group)
+{
+	unsigned int i = 0;
+
+	if (!node_group)
+		return;
+
+	while (node_group[i])
+		i++;
+
+	while (i--)
+		software_node_unregister(node_group[i]);
+}
+EXPORT_SYMBOL_GPL(software_node_unregister_node_group);
+
+/**
+ * software_node_register - Register static software node
+ * @node: The software node to be registered
+ */
+int software_node_register(const struct software_node *node)
+{
+	struct swnode *parent = software_node_to_swnode(node->parent);
+
+	if (software_node_to_swnode(node))
+		return -EEXIST;
+
+	if (node->parent && !parent)
+		return -EINVAL;
+
+	return PTR_ERR_OR_ZERO(swnode_register(node, parent, 0));
+}
+EXPORT_SYMBOL_GPL(software_node_register);
+
+/**
+ * software_node_unregister - Unregister static software node
+ * @node: The software node to be unregistered
+ */
+void software_node_unregister(const struct software_node *node)
+{
+	struct swnode *swnode;
+
+	swnode = software_node_to_swnode(node);
+	if (swnode)
+		fwnode_remove_software_node(&swnode->fwnode);
+}
+EXPORT_SYMBOL_GPL(software_node_unregister);
+
+struct fwnode_handle *
+fwnode_create_software_node(const struct property_entry *properties,
+			    const struct fwnode_handle *parent)
+{
+	struct fwnode_handle *fwnode;
+	struct software_node *node;
+	struct swnode *p;
+
+	if (IS_ERR(parent))
+		return ERR_CAST(parent);
+
+	p = to_swnode(parent);
+	if (parent && !p)
+		return ERR_PTR(-EINVAL);
+
+	node = software_node_alloc(properties);
+	if (IS_ERR(node))
+		return ERR_CAST(node);
+
+	node->parent = p ? p->node : NULL;
+
+	fwnode = swnode_register(node, p, 1);
+	if (IS_ERR(fwnode))
+		software_node_free(node);
+
+	return fwnode;
+}
+EXPORT_SYMBOL_GPL(fwnode_create_software_node);
+
+void fwnode_remove_software_node(struct fwnode_handle *fwnode)
+{
+	struct swnode *swnode = to_swnode(fwnode);
+
+	if (!swnode)
+		return;
+
+	swnode_put(swnode);
+}
+EXPORT_SYMBOL_GPL(fwnode_remove_software_node);
+
+/**
+ * device_add_software_node - Assign software node to a device
+ * @dev: The device the software node is meant for.
+ * @node: The software node.
+ *
+ * This function will make @node the secondary firmware node pointer of @dev. If
+ * @dev has no primary node, then @node will become the primary node. The
+ * function will register @node automatically if it wasn't already registered.
+ */
+int device_add_software_node(struct device *dev, const struct software_node *node)
+{
+	struct swnode *swnode;
+	int ret;
+
+	/* Only one software node per device. */
+	if (dev_to_swnode(dev))
+		return -EBUSY;
+
+	swnode = software_node_to_swnode(node);
+	if (swnode) {
+		swnode_get(swnode);
+	} else {
+		ret = software_node_register(node);
+		if (ret)
+			return ret;
+
+		swnode = software_node_to_swnode(node);
+	}
+
+	set_secondary_fwnode(dev, &swnode->fwnode);
+
+	/*
+	 * If the device has been fully registered by the time this function is
+	 * called, software_node_notify() must be called separately so that the
+	 * symlinks get created and the reference count of the node is kept in
+	 * balance.
+	 */
+	if (device_is_registered(dev))
+		software_node_notify(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(device_add_software_node);
+
+/**
+ * device_remove_software_node - Remove device's software node
+ * @dev: The device with the software node.
+ *
+ * This function will unregister the software node of @dev.
+ */
+void device_remove_software_node(struct device *dev)
+{
+	struct swnode *swnode;
+
+	swnode = dev_to_swnode(dev);
+	if (!swnode)
+		return;
+
+	if (device_is_registered(dev))
+		software_node_notify_remove(dev);
+
+	set_secondary_fwnode(dev, NULL);
+	swnode_put(swnode);
+}
+EXPORT_SYMBOL_GPL(device_remove_software_node);
+
+/**
+ * device_create_managed_software_node - Create a software node for a device
+ * @dev: The device the software node is assigned to.
+ * @properties: Device properties for the software node.
+ * @parent: Parent of the software node.
+ *
+ * Creates a software node as a managed resource for @dev, which means the
+ * lifetime of the newly created software node is tied to the lifetime of @dev.
+ * Software nodes created with this function should not be reused or shared
+ * because of that. The function takes a deep copy of @properties for the
+ * software node.
+ *
+ * Since the new software node is assigned directly to @dev, and since it should
+ * not be shared, it is not returned to the caller. The function returns 0 on
+ * success, and errno in case of an error.
+ */
+int device_create_managed_software_node(struct device *dev,
+					const struct property_entry *properties,
+					const struct software_node *parent)
+{
+	struct fwnode_handle *p = software_node_fwnode(parent);
+	struct fwnode_handle *fwnode;
+
+	if (parent && !p)
+		return -EINVAL;
+
+	fwnode = fwnode_create_software_node(properties, p);
+	if (IS_ERR(fwnode))
+		return PTR_ERR(fwnode);
+
+	to_swnode(fwnode)->managed = true;
+	set_secondary_fwnode(dev, fwnode);
+
+	if (device_is_registered(dev))
+		software_node_notify(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(device_create_managed_software_node);
+
+void software_node_notify(struct device *dev)
+{
+	struct swnode *swnode;
+	int ret;
+
+	swnode = dev_to_swnode(dev);
+	if (!swnode)
+		return;
+
+	/*
+	 * When the software node is the device's secondary firmware node,
+	 * the core only records the owning device on the primary fwnode
+	 * (see device_add()). fw_devlink resolves a supplier device through
+	 * fwnode->dev, so without this a consumer referencing the software
+	 * node could never find the supplier device and would defer forever.
+	 * Make fwnode.dev point to its owner in that case.
+	 */
+	if (!device_match_fwnode(dev, &swnode->fwnode) && !swnode->fwnode.dev)
+		swnode->fwnode.dev = dev;
+
+	swnode_get(swnode);
+	ret = sysfs_create_link(&dev->kobj, &swnode->kobj, "software_node");
+	if (ret)
+		return;
+
+	ret = sysfs_create_link(&swnode->kobj, &dev->kobj, dev_name(dev));
+	if (ret) {
+		sysfs_remove_link(&dev->kobj, "software_node");
+		return;
+	}
+}
+
+void software_node_notify_remove(struct device *dev)
+{
+	struct swnode *swnode;
+
+	swnode = dev_to_swnode(dev);
+	if (!swnode)
+		return;
+
+	sysfs_remove_link(&swnode->kobj, dev_name(dev));
+	sysfs_remove_link(&dev->kobj, "software_node");
+
+	/*
+	 * Drop the device pointer mirrored onto a secondary software node in
+	 * software_node_notify(). For a primary software node the core owns
+	 * fwnode->dev and clears it in device_del().
+	 */
+	if (!device_match_fwnode(dev, &swnode->fwnode) && swnode->fwnode.dev == dev)
+		swnode->fwnode.dev = NULL;
+
+	swnode_put(swnode);
+
+	if (swnode->managed) {
+		set_secondary_fwnode(dev, NULL);
+		swnode_put(swnode);
+	}
+}
+
+void __init software_node_init(void)
+{
+	swnode_kset = kset_create_and_add("software_nodes", NULL, kernel_kobj);
+	if (!swnode_kset)
+		pr_err("failed to register software nodes\n");
+}