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, 793 insertions, 0 deletions

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
new file mode 100644
index 000000000..8b1e76407
--- /dev/null
+++ b/drivers/of/platform.c
@@ -0,0 +1,793 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
+ *			 <benh@kernel.crashing.org>
+ *    and		 Arnd Bergmann, IBM Corp.
+ *    Merged from powerpc/kernel/of_platform.c and
+ *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
+ */
+
+#define pr_fmt(fmt)	"OF: " fmt
+
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/amba/bus.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/sysfb.h>
+
+#include "of_private.h"
+
+/**
+ * of_find_device_by_node - Find the platform_device associated with a node
+ * @np: Pointer to device tree node
+ *
+ * Takes a reference to the embedded struct device which needs to be dropped
+ * after use.
+ *
+ * Return: platform_device pointer, or NULL if not found
+ */
+struct platform_device *of_find_device_by_node(struct device_node *np)
+{
+	struct device *dev;
+
+	dev = bus_find_device_by_of_node(&platform_bus_type, np);
+	return dev ? to_platform_device(dev) : NULL;
+}
+EXPORT_SYMBOL(of_find_device_by_node);
+
+int of_device_add(struct platform_device *ofdev)
+{
+	BUG_ON(ofdev->dev.of_node == NULL);
+
+	/* name and id have to be set so that the platform bus doesn't get
+	 * confused on matching */
+	ofdev->name = dev_name(&ofdev->dev);
+	ofdev->id = PLATFORM_DEVID_NONE;
+
+	/*
+	 * If this device has not binding numa node in devicetree, that is
+	 * of_node_to_nid returns NUMA_NO_NODE. device_add will assume that this
+	 * device is on the same node as the parent.
+	 */
+	set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
+
+	return device_add(&ofdev->dev);
+}
+
+int of_device_register(struct platform_device *pdev)
+{
+	device_initialize(&pdev->dev);
+	return of_device_add(pdev);
+}
+EXPORT_SYMBOL(of_device_register);
+
+void of_device_unregister(struct platform_device *ofdev)
+{
+	device_unregister(&ofdev->dev);
+}
+EXPORT_SYMBOL(of_device_unregister);
+
+#ifdef CONFIG_OF_ADDRESS
+static const struct of_device_id of_skipped_node_table[] = {
+	{ .compatible = "operating-points-v2", },
+	{} /* Empty terminated list */
+};
+
+/*
+ * The following routines scan a subtree and registers a device for
+ * each applicable node.
+ *
+ * Note: sparc doesn't use these routines because it has a different
+ * mechanism for creating devices from device tree nodes.
+ */
+
+/**
+ * of_device_alloc - Allocate and initialize an of_device
+ * @np: device node to assign to device
+ * @bus_id: Name to assign to the device.  May be null to use default name.
+ * @parent: Parent device.
+ */
+struct platform_device *of_device_alloc(struct device_node *np,
+				  const char *bus_id,
+				  struct device *parent)
+{
+	struct platform_device *dev;
+	int rc, i, num_reg = 0;
+	struct resource *res;
+
+	dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
+	if (!dev)
+		return NULL;
+
+	/* count the io resources */
+	num_reg = of_address_count(np);
+
+	/* Populate the resource table */
+	if (num_reg) {
+		res = kzalloc_objs(*res, num_reg);
+		if (!res) {
+			platform_device_put(dev);
+			return NULL;
+		}
+
+		dev->num_resources = num_reg;
+		dev->resource = res;
+		for (i = 0; i < num_reg; i++, res++) {
+			rc = of_address_to_resource(np, i, res);
+			WARN_ON(rc);
+		}
+	}
+
+	/* setup generic device info */
+	platform_device_set_of_node(dev, np);
+	dev->dev.parent = parent ? : &platform_bus;
+
+	if (bus_id)
+		dev_set_name(&dev->dev, "%s", bus_id);
+	else
+		of_device_make_bus_id(&dev->dev);
+
+	return dev;
+}
+EXPORT_SYMBOL(of_device_alloc);
+
+/**
+ * of_platform_device_create_pdata - Alloc, initialize and register an of_device
+ * @np: pointer to node to create device for
+ * @bus_id: name to assign device
+ * @platform_data: pointer to populate platform_data pointer with
+ * @parent: Linux device model parent device.
+ *
+ * Return: Pointer to created platform device, or NULL if a device was not
+ * registered.  Unavailable devices will not get registered.
+ */
+static struct platform_device *of_platform_device_create_pdata(
+					struct device_node *np,
+					const char *bus_id,
+					void *platform_data,
+					struct device *parent)
+{
+	struct platform_device *dev;
+
+	pr_debug("create platform device: %pOF\n", np);
+
+	if (!of_device_is_available(np) ||
+	    of_node_test_and_set_flag(np, OF_POPULATED))
+		return NULL;
+
+	dev = of_device_alloc(np, bus_id, parent);
+	if (!dev)
+		goto err_clear_flag;
+
+	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	if (!dev->dev.dma_mask)
+		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+	dev->dev.bus = &platform_bus_type;
+	dev->dev.platform_data = platform_data;
+	of_msi_configure(&dev->dev, dev->dev.of_node);
+
+	if (of_device_add(dev) != 0) {
+		platform_device_put(dev);
+		goto err_clear_flag;
+	}
+
+	return dev;
+
+err_clear_flag:
+	of_node_clear_flag(np, OF_POPULATED);
+	return NULL;
+}
+
+/**
+ * of_platform_device_create - Alloc, initialize and register an of_device
+ * @np: pointer to node to create device for
+ * @bus_id: name to assign device
+ * @parent: Linux device model parent device.
+ *
+ * Return: Pointer to created platform device, or NULL if a device was not
+ * registered.  Unavailable devices will not get registered.
+ */
+struct platform_device *of_platform_device_create(struct device_node *np,
+					    const char *bus_id,
+					    struct device *parent)
+{
+	return of_platform_device_create_pdata(np, bus_id, NULL, parent);
+}
+EXPORT_SYMBOL(of_platform_device_create);
+
+#ifdef CONFIG_ARM_AMBA
+static struct amba_device *of_amba_device_create(struct device_node *node,
+						 const char *bus_id,
+						 void *platform_data,
+						 struct device *parent)
+{
+	struct amba_device *dev;
+	int ret;
+
+	pr_debug("Creating amba device %pOF\n", node);
+
+	if (!of_device_is_available(node) ||
+	    of_node_test_and_set_flag(node, OF_POPULATED))
+		return NULL;
+
+	dev = amba_device_alloc(NULL, 0, 0);
+	if (!dev)
+		goto err_clear_flag;
+
+	/* AMBA devices only support a single DMA mask */
+	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
+
+	/* setup generic device info */
+	device_set_node(&dev->dev, of_fwnode_handle(node));
+	dev->dev.parent = parent ? : &platform_bus;
+	dev->dev.platform_data = platform_data;
+	if (bus_id)
+		dev_set_name(&dev->dev, "%s", bus_id);
+	else
+		of_device_make_bus_id(&dev->dev);
+
+	/* Allow the HW Peripheral ID to be overridden */
+	of_property_read_u32(node, "arm,primecell-periphid", &dev->periphid);
+
+	ret = of_address_to_resource(node, 0, &dev->res);
+	if (ret) {
+		pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
+		       ret, node);
+		goto err_free;
+	}
+
+	ret = amba_device_add(dev, &iomem_resource);
+	if (ret) {
+		pr_err("amba_device_add() failed (%d) for %pOF\n",
+		       ret, node);
+		goto err_free;
+	}
+
+	return dev;
+
+err_free:
+	amba_device_put(dev);
+err_clear_flag:
+	of_node_clear_flag(node, OF_POPULATED);
+	return NULL;
+}
+#else /* CONFIG_ARM_AMBA */
+static struct amba_device *of_amba_device_create(struct device_node *node,
+						 const char *bus_id,
+						 void *platform_data,
+						 struct device *parent)
+{
+	return NULL;
+}
+#endif /* CONFIG_ARM_AMBA */
+
+/*
+ * of_dev_lookup() - Given a device node, lookup the preferred Linux name
+ */
+static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
+				 struct device_node *np)
+{
+	const struct of_dev_auxdata *auxdata;
+	struct resource res;
+	int compatible = 0;
+
+	if (!lookup)
+		return NULL;
+
+	auxdata = lookup;
+	for (; auxdata->compatible; auxdata++) {
+		if (!of_device_is_compatible(np, auxdata->compatible))
+			continue;
+		compatible++;
+		if (!of_address_to_resource(np, 0, &res))
+			if (res.start != auxdata->phys_addr)
+				continue;
+		pr_debug("%pOF: devname=%s\n", np, auxdata->name);
+		return auxdata;
+	}
+
+	if (!compatible)
+		return NULL;
+
+	/* Try compatible match if no phys_addr and name are specified */
+	auxdata = lookup;
+	for (; auxdata->compatible; auxdata++) {
+		if (!of_device_is_compatible(np, auxdata->compatible))
+			continue;
+		if (!auxdata->phys_addr && !auxdata->name) {
+			pr_debug("%pOF: compatible match\n", np);
+			return auxdata;
+		}
+	}
+
+	return NULL;
+}
+
+/**
+ * of_platform_bus_create() - Create a device for a node and its children.
+ * @bus: device node of the bus to instantiate
+ * @matches: match table for bus nodes
+ * @lookup: auxdata table for matching id and platform_data with device nodes
+ * @parent: parent for new device, or NULL for top level.
+ * @strict: require compatible property
+ *
+ * Creates a platform_device for the provided device_node, and optionally
+ * recursively create devices for all the child nodes.
+ */
+static int of_platform_bus_create(struct device_node *bus,
+				  const struct of_device_id *matches,
+				  const struct of_dev_auxdata *lookup,
+				  struct device *parent, bool strict)
+{
+	const struct of_dev_auxdata *auxdata;
+	struct platform_device *dev;
+	const char *bus_id = NULL;
+	void *platform_data = NULL;
+	int rc = 0;
+
+	/* Make sure it has a compatible property */
+	if (strict && (!of_property_present(bus, "compatible"))) {
+		pr_debug("%s() - skipping %pOF, no compatible prop\n",
+			 __func__, bus);
+		return 0;
+	}
+
+	/* Skip nodes for which we don't want to create devices */
+	if (unlikely(of_match_node(of_skipped_node_table, bus))) {
+		pr_debug("%s() - skipping %pOF node\n", __func__, bus);
+		return 0;
+	}
+
+	if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
+		pr_debug("%s() - skipping %pOF, already populated\n",
+			__func__, bus);
+		return 0;
+	}
+
+	auxdata = of_dev_lookup(lookup, bus);
+	if (auxdata) {
+		bus_id = auxdata->name;
+		platform_data = auxdata->platform_data;
+	}
+
+	if (of_device_is_compatible(bus, "arm,primecell")) {
+		/*
+		 * Don't return an error here to keep compatibility with older
+		 * device tree files.
+		 */
+		of_amba_device_create(bus, bus_id, platform_data, parent);
+		return 0;
+	}
+
+	dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
+	if (!dev || !of_match_node(matches, bus))
+		return 0;
+
+	for_each_child_of_node_scoped(bus, child) {
+		pr_debug("   create child: %pOF\n", child);
+		rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
+		if (rc)
+			break;
+	}
+	of_node_set_flag(bus, OF_POPULATED_BUS);
+	return rc;
+}
+
+/**
+ * of_platform_bus_probe() - Probe the device-tree for platform buses
+ * @root: parent of the first level to probe or NULL for the root of the tree
+ * @matches: match table for bus nodes
+ * @parent: parent to hook devices from, NULL for toplevel
+ *
+ * Note that children of the provided root are not instantiated as devices
+ * unless the specified root itself matches the bus list and is not NULL.
+ */
+int of_platform_bus_probe(struct device_node *root,
+			  const struct of_device_id *matches,
+			  struct device *parent)
+{
+	int rc = 0;
+
+	root = root ? of_node_get(root) : of_find_node_by_path("/");
+	if (!root)
+		return -EINVAL;
+
+	pr_debug("%s()\n", __func__);
+	pr_debug(" starting at: %pOF\n", root);
+
+	/* Do a self check of bus type, if there's a match, create children */
+	if (of_match_node(matches, root)) {
+		rc = of_platform_bus_create(root, matches, NULL, parent, false);
+	} else {
+		for_each_child_of_node_scoped(root, child) {
+			if (!of_match_node(matches, child))
+				continue;
+			rc = of_platform_bus_create(child, matches, NULL, parent, false);
+			if (rc)
+				break;
+		}
+	}
+
+	of_node_put(root);
+	return rc;
+}
+EXPORT_SYMBOL(of_platform_bus_probe);
+
+/**
+ * of_platform_populate() - Populate platform_devices from device tree data
+ * @root: parent of the first level to probe or NULL for the root of the tree
+ * @matches: match table, NULL to use the default
+ * @lookup: auxdata table for matching id and platform_data with device nodes
+ * @parent: parent to hook devices from, NULL for toplevel
+ *
+ * Similar to of_platform_bus_probe(), this function walks the device tree
+ * and creates devices from nodes.  It differs in that it follows the modern
+ * convention of requiring all device nodes to have a 'compatible' property,
+ * and it is suitable for creating devices which are children of the root
+ * node (of_platform_bus_probe will only create children of the root which
+ * are selected by the @matches argument).
+ *
+ * New board support should be using this function instead of
+ * of_platform_bus_probe().
+ *
+ * Return: 0 on success, < 0 on failure.
+ */
+int of_platform_populate(struct device_node *root,
+			const struct of_device_id *matches,
+			const struct of_dev_auxdata *lookup,
+			struct device *parent)
+{
+	int rc = 0;
+
+	root = root ? of_node_get(root) : of_find_node_by_path("/");
+	if (!root)
+		return -EINVAL;
+
+	pr_debug("%s()\n", __func__);
+	pr_debug(" starting at: %pOF\n", root);
+
+	device_links_supplier_sync_state_pause();
+	for_each_child_of_node_scoped(root, child) {
+		rc = of_platform_bus_create(child, matches, lookup, parent, true);
+		if (rc)
+			break;
+	}
+	device_links_supplier_sync_state_resume();
+
+	of_node_set_flag(root, OF_POPULATED_BUS);
+
+	of_node_put(root);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(of_platform_populate);
+
+int of_platform_default_populate(struct device_node *root,
+				 const struct of_dev_auxdata *lookup,
+				 struct device *parent)
+{
+	static const struct of_device_id match_table[] = {
+		{ .compatible = "simple-bus", },
+		{ .compatible = "simple-mfd", },
+		{ .compatible = "isa", },
+#ifdef CONFIG_ARM_AMBA
+		{ .compatible = "arm,amba-bus", },
+#endif /* CONFIG_ARM_AMBA */
+		{} /* Empty terminated list */
+	};
+
+	return of_platform_populate(root, match_table, lookup, parent);
+}
+EXPORT_SYMBOL_GPL(of_platform_default_populate);
+
+static const struct of_device_id reserved_mem_matches[] = {
+	{ .compatible = "phram" },
+	{ .compatible = "qcom,rmtfs-mem" },
+	{ .compatible = "qcom,cmd-db" },
+	{ .compatible = "qcom,smem" },
+	{ .compatible = "ramoops" },
+	{ .compatible = "nvmem-rmem" },
+	{ .compatible = "google,open-dice" },
+	{}
+};
+
+static int __init of_platform_default_populate_init(void)
+{
+	struct device_node *node, *reserved;
+
+	device_links_supplier_sync_state_pause();
+
+	if (IS_ENABLED(CONFIG_PPC)) {
+		struct device_node *boot_display = NULL;
+		struct platform_device *dev;
+		int display_number = 0;
+		int ret;
+
+		/* Check if we have a MacOS display without a node spec */
+		if (of_property_present(of_chosen, "linux,bootx-noscreen")) {
+			/*
+			 * The old code tried to work out which node was the MacOS
+			 * display based on the address. I'm dropping that since the
+			 * lack of a node spec only happens with old BootX versions
+			 * (users can update) and with this code, they'll still get
+			 * a display (just not the palette hacks).
+			 */
+			dev = platform_device_alloc("bootx-noscreen", 0);
+			if (WARN_ON(!dev))
+				return -ENOMEM;
+			ret = platform_device_add(dev);
+			if (WARN_ON(ret)) {
+				platform_device_put(dev);
+				return ret;
+			}
+		}
+
+		/*
+		 * For OF framebuffers, first create the device for the boot display,
+		 * then for the other framebuffers. Only fail for the boot display;
+		 * ignore errors for the rest.
+		 */
+		for_each_node_by_type(node, "display") {
+			if (!of_property_read_bool(node, "linux,opened") ||
+			    !of_property_read_bool(node, "linux,boot-display"))
+				continue;
+			dev = of_platform_device_create(node, "of-display", NULL);
+			of_node_put(node);
+			if (WARN_ON(!dev))
+				return -ENOMEM;
+			boot_display = node;
+			display_number++;
+			break;
+		}
+		for_each_node_by_type(node, "display") {
+			char buf[14];
+			const char *of_display_format = "of-display.%d";
+
+			if (!of_property_read_bool(node, "linux,opened") || node == boot_display)
+				continue;
+			ret = snprintf(buf, sizeof(buf), of_display_format, display_number++);
+			if (ret < sizeof(buf))
+				of_platform_device_create(node, buf, NULL);
+		}
+
+	} else {
+		/*
+		 * Handle certain compatibles explicitly, since we don't want to create
+		 * platform_devices for every node in /reserved-memory with a
+		 * "compatible",
+		 */
+		reserved = of_find_node_by_path("/reserved-memory");
+		if (reserved) {
+			for_each_child_of_node(reserved, node) {
+				if (of_match_node(reserved_mem_matches, node))
+					of_platform_device_create(node, NULL, NULL);
+			}
+			of_node_put(reserved);
+		}
+
+		node = of_find_node_by_path("/firmware");
+		if (node) {
+			of_platform_default_populate(node, NULL, NULL);
+			of_node_put(node);
+		}
+
+		node = of_get_compatible_child(of_chosen, "simple-framebuffer");
+		if (node) {
+			/*
+			 * Since a "simple-framebuffer" device is already added
+			 * here, disable the Generic System Framebuffers (sysfb)
+			 * to prevent it from registering another device for the
+			 * system framebuffer later (e.g: using the screen_info
+			 * data that may had been filled as well).
+			 *
+			 * This can happen for example on DT systems that do EFI
+			 * booting and may provide a GOP handle to the EFI stub.
+			 */
+			sysfb_disable(NULL);
+			of_platform_device_create(node, NULL, NULL);
+			of_node_put(node);
+		}
+
+		/* Populate everything else. */
+		of_platform_default_populate(NULL, NULL, NULL);
+	}
+
+	return 0;
+}
+arch_initcall_sync(of_platform_default_populate_init);
+
+static int __init of_platform_sync_state_init(void)
+{
+	device_links_supplier_sync_state_resume();
+	return 0;
+}
+late_initcall_sync(of_platform_sync_state_init);
+
+int of_platform_device_destroy(struct device *dev, void *data)
+{
+	/* Do not touch devices not populated from the device tree */
+	if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
+		return 0;
+
+	/* Recurse for any nodes that were treated as busses */
+	if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
+		device_for_each_child(dev, NULL, of_platform_device_destroy);
+
+	of_node_clear_flag(dev->of_node, OF_POPULATED);
+	of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
+
+	if (dev->bus == &platform_bus_type)
+		platform_device_unregister(to_platform_device(dev));
+#ifdef CONFIG_ARM_AMBA
+	else if (dev->bus == &amba_bustype)
+		amba_device_unregister(to_amba_device(dev));
+#endif
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_platform_device_destroy);
+
+/**
+ * of_platform_depopulate() - Remove devices populated from device tree
+ * @parent: device which children will be removed
+ *
+ * Complementary to of_platform_populate(), this function removes children
+ * of the given device (and, recursively, their children) that have been
+ * created from their respective device tree nodes (and only those,
+ * leaving others - eg. manually created - unharmed).
+ */
+void of_platform_depopulate(struct device *parent)
+{
+	if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
+		device_for_each_child_reverse(parent, NULL, of_platform_device_destroy);
+		of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
+	}
+}
+EXPORT_SYMBOL_GPL(of_platform_depopulate);
+
+static void devm_of_platform_populate_release(struct device *dev, void *res)
+{
+	of_platform_depopulate(*(struct device **)res);
+}
+
+/**
+ * devm_of_platform_populate() - Populate platform_devices from device tree data
+ * @dev: device that requested to populate from device tree data
+ *
+ * Similar to of_platform_populate(), but will automatically call
+ * of_platform_depopulate() when the device is unbound from the bus.
+ *
+ * Return: 0 on success, < 0 on failure.
+ */
+int devm_of_platform_populate(struct device *dev)
+{
+	struct device **ptr;
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	ptr = devres_alloc(devm_of_platform_populate_release,
+			   sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
+	if (ret) {
+		devres_free(ptr);
+	} else {
+		*ptr = dev;
+		devres_add(dev, ptr);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_of_platform_populate);
+
+static int devm_of_platform_match(struct device *dev, void *res, void *data)
+{
+	struct device **ptr = res;
+
+	if (!ptr) {
+		WARN_ON(!ptr);
+		return 0;
+	}
+
+	return *ptr == data;
+}
+
+/**
+ * devm_of_platform_depopulate() - Remove devices populated from device tree
+ * @dev: device that requested to depopulate from device tree data
+ *
+ * Complementary to devm_of_platform_populate(), this function removes children
+ * of the given device (and, recursively, their children) that have been
+ * created from their respective device tree nodes (and only those,
+ * leaving others - eg. manually created - unharmed).
+ */
+void devm_of_platform_depopulate(struct device *dev)
+{
+	int ret;
+
+	ret = devres_release(dev, devm_of_platform_populate_release,
+			     devm_of_platform_match, dev);
+
+	WARN_ON(ret);
+}
+EXPORT_SYMBOL_GPL(devm_of_platform_depopulate);
+
+#ifdef CONFIG_OF_DYNAMIC
+static int of_platform_notify(struct notifier_block *nb,
+				unsigned long action, void *arg)
+{
+	struct of_reconfig_data *rd = arg;
+	struct platform_device *pdev_parent, *pdev;
+	bool children_left;
+	struct device_node *parent;
+
+	switch (of_reconfig_get_state_change(action, rd)) {
+	case OF_RECONFIG_CHANGE_ADD:
+		parent = rd->dn->parent;
+		/* verify that the parent is a bus (or the root node) */
+		if (!of_node_is_root(parent) &&
+		    !of_node_check_flag(parent, OF_POPULATED_BUS))
+			return NOTIFY_OK;	/* not for us */
+
+		/* already populated? (driver using of_populate manually) */
+		if (of_node_check_flag(rd->dn, OF_POPULATED))
+			return NOTIFY_OK;
+
+		/* pdev_parent may be NULL when no bus platform device */
+		pdev_parent = of_find_device_by_node(parent);
+		pdev = of_platform_device_create(rd->dn, NULL,
+				pdev_parent ? &pdev_parent->dev : NULL);
+		platform_device_put(pdev_parent);
+
+		if (pdev == NULL) {
+			pr_err("%s: failed to create for '%pOF'\n",
+					__func__, rd->dn);
+			/* of_platform_device_create tosses the error code */
+			return notifier_from_errno(-EINVAL);
+		}
+		break;
+
+	case OF_RECONFIG_CHANGE_REMOVE:
+
+		/* already depopulated? */
+		if (!of_node_check_flag(rd->dn, OF_POPULATED))
+			return NOTIFY_OK;
+
+		/* find our device by node */
+		pdev = of_find_device_by_node(rd->dn);
+		if (pdev == NULL)
+			return NOTIFY_OK;	/* no? not meant for us */
+
+		/* unregister takes one ref away */
+		of_platform_device_destroy(&pdev->dev, &children_left);
+
+		/* and put the reference of the find */
+		platform_device_put(pdev);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block platform_of_notifier = {
+	.notifier_call = of_platform_notify,
+};
+
+void of_platform_register_reconfig_notifier(void)
+{
+	WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
+}
+#endif /* CONFIG_OF_DYNAMIC */
+
+#endif /* CONFIG_OF_ADDRESS */