Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 638 insertions, 0 deletions

diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
new file mode 100644
index 000000000..d9faadbe9
--- /dev/null
+++ b/net/ethernet/eth.c
@@ -0,0 +1,638 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Ethernet-type device handling.
+ *
+ * Version:	@(#)eth.c	1.0.7	05/25/93
+ *
+ * Authors:	Ross Biro
+ *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
+ *		Mark Evans, <evansmp@uhura.aston.ac.uk>
+ *		Florian  La Roche, <rzsfl@rz.uni-sb.de>
+ *		Alan Cox, <gw4pts@gw4pts.ampr.org>
+ *
+ * Fixes:
+ *		Mr Linux	: Arp problems
+ *		Alan Cox	: Generic queue tidyup (very tiny here)
+ *		Alan Cox	: eth_header ntohs should be htons
+ *		Alan Cox	: eth_rebuild_header missing an htons and
+ *				  minor other things.
+ *		Tegge		: Arp bug fixes.
+ *		Florian		: Removed many unnecessary functions, code cleanup
+ *				  and changes for new arp and skbuff.
+ *		Alan Cox	: Redid header building to reflect new format.
+ *		Alan Cox	: ARP only when compiled with CONFIG_INET
+ *		Greg Page	: 802.2 and SNAP stuff.
+ *		Alan Cox	: MAC layer pointers/new format.
+ *		Paul Gortmaker	: eth_copy_and_sum shouldn't csum padding.
+ *		Alan Cox	: Protect against forwarding explosions with
+ *				  older network drivers and IFF_ALLMULTI.
+ *	Christer Weinigel	: Better rebuild header message.
+ *             Andrew Morton    : 26Feb01: kill ether_setup() - use netdev_boot_setup().
+ */
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/ip.h>
+#include <linux/netdevice.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/if_ether.h>
+#include <linux/of_net.h>
+#include <linux/pci.h>
+#include <linux/property.h>
+#include <net/dst.h>
+#include <net/arp.h>
+#include <net/sock.h>
+#include <net/ipv6.h>
+#include <net/ip.h>
+#include <net/dsa.h>
+#include <net/flow_dissector.h>
+#include <net/gro.h>
+#include <linux/uaccess.h>
+#include <net/pkt_sched.h>
+
+/**
+ * eth_header - create the Ethernet header
+ * @skb:	buffer to alter
+ * @dev:	source device
+ * @type:	Ethernet type field
+ * @daddr: destination address (NULL leave destination address)
+ * @saddr: source address (NULL use device source address)
+ * @len:   packet length (<= skb->len)
+ *
+ *
+ * Set the protocol type. For a packet of type ETH_P_802_3/2 we put the length
+ * in here instead.
+ */
+int eth_header(struct sk_buff *skb, struct net_device *dev,
+	       unsigned short type,
+	       const void *daddr, const void *saddr, unsigned int len)
+{
+	struct ethhdr *eth = skb_push(skb, ETH_HLEN);
+
+	if (type != ETH_P_802_3 && type != ETH_P_802_2)
+		eth->h_proto = htons(type);
+	else
+		eth->h_proto = htons(len);
+
+	/*
+	 *      Set the source hardware address.
+	 */
+
+	if (!saddr)
+		saddr = dev->dev_addr;
+	memcpy(eth->h_source, saddr, ETH_ALEN);
+
+	if (daddr) {
+		memcpy(eth->h_dest, daddr, ETH_ALEN);
+		return ETH_HLEN;
+	}
+
+	/*
+	 *      Anyway, the loopback-device should never use this function...
+	 */
+
+	if (dev->flags & (IFF_LOOPBACK | IFF_NOARP)) {
+		eth_zero_addr(eth->h_dest);
+		return ETH_HLEN;
+	}
+
+	return -ETH_HLEN;
+}
+EXPORT_SYMBOL(eth_header);
+
+/**
+ * eth_get_headlen - determine the length of header for an ethernet frame
+ * @dev: pointer to network device
+ * @data: pointer to start of frame
+ * @len: total length of frame
+ *
+ * Make a best effort attempt to pull the length for all of the headers for
+ * a given frame in a linear buffer.
+ */
+u32 eth_get_headlen(const struct net_device *dev, const void *data, u32 len)
+{
+	const unsigned int flags = FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
+	const struct ethhdr *eth = (const struct ethhdr *)data;
+	struct flow_keys_basic keys;
+
+	/* this should never happen, but better safe than sorry */
+	if (unlikely(len < sizeof(*eth)))
+		return len;
+
+	/* parse any remaining L2/L3 headers, check for L4 */
+	if (!skb_flow_dissect_flow_keys_basic(dev_net(dev), NULL, &keys, data,
+					      eth->h_proto, sizeof(*eth),
+					      len, flags))
+		return max_t(u32, keys.control.thoff, sizeof(*eth));
+
+	/* parse for any L4 headers */
+	return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
+}
+EXPORT_SYMBOL(eth_get_headlen);
+
+/**
+ * eth_type_trans - determine the packet's protocol ID.
+ * @skb: received socket data
+ * @dev: receiving network device
+ *
+ * The rule here is that we
+ * assume 802.3 if the type field is short enough to be a length.
+ * This is normal practice and works for any 'now in use' protocol.
+ */
+__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)
+{
+	const unsigned short *sap;
+	const struct ethhdr *eth;
+	__be16 res;
+
+	skb->dev = dev;
+	skb_reset_mac_header(skb);
+
+	eth = eth_skb_pull_mac(skb);
+	eth_skb_pkt_type(skb, dev);
+
+	/*
+	 * Some variants of DSA tagging don't have an ethertype field
+	 * at all, so we check here whether one of those tagging
+	 * variants has been configured on the receiving interface,
+	 * and if so, set skb->protocol without looking at the packet.
+	 */
+	if (unlikely(netdev_uses_dsa(dev)))
+		return htons(ETH_P_XDSA);
+
+	if (likely(eth_proto_is_802_3(eth->h_proto)))
+		return eth->h_proto;
+
+	/*
+	 *      This is a magic hack to spot IPX packets. Older Novell breaks
+	 *      the protocol design and runs IPX over 802.3 without an 802.2 LLC
+	 *      layer. We look for FFFF which isn't a used 802.2 SSAP/DSAP. This
+	 *      won't work for fault tolerant netware but does for the rest.
+	 *	We use skb->dev as temporary storage to not hit
+	 *	CONFIG_STACKPROTECTOR_STRONG=y costs on some platforms.
+	 */
+	sap = skb_header_pointer(skb, 0, sizeof(*sap), &skb->dev);
+	res = (sap && *sap == 0xFFFF) ? htons(ETH_P_802_3) : htons(ETH_P_802_2);
+
+	/* restore skb->dev in case it was mangled by skb_header_pointer(). */
+	skb->dev = dev;
+	return res;
+}
+EXPORT_SYMBOL(eth_type_trans);
+
+int eth_header_parse(const struct sk_buff *skb, const struct net_device *dev,
+		     unsigned char *haddr)
+{
+	const struct ethhdr *eth = eth_hdr(skb);
+
+	memcpy(haddr, eth->h_source, ETH_ALEN);
+	return ETH_ALEN;
+}
+EXPORT_SYMBOL(eth_header_parse);
+
+/**
+ * eth_header_cache - fill cache entry from neighbour
+ * @neigh: source neighbour
+ * @hh: destination cache entry
+ * @type: Ethernet type field
+ *
+ * Create an Ethernet header template from the neighbour.
+ */
+int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type)
+{
+	struct ethhdr *eth;
+	const struct net_device *dev = neigh->dev;
+
+	eth = (struct ethhdr *)
+	    (((u8 *) hh->hh_data) + (HH_DATA_OFF(sizeof(*eth))));
+
+	if (type == htons(ETH_P_802_3))
+		return -1;
+
+	eth->h_proto = type;
+	memcpy(eth->h_source, dev->dev_addr, ETH_ALEN);
+	memcpy(eth->h_dest, neigh->ha, ETH_ALEN);
+
+	/* Pairs with READ_ONCE() in neigh_resolve_output(),
+	 * neigh_hh_output() and neigh_update_hhs().
+	 */
+	smp_store_release(&hh->hh_len, ETH_HLEN);
+
+	return 0;
+}
+EXPORT_SYMBOL(eth_header_cache);
+
+/**
+ * eth_header_cache_update - update cache entry
+ * @hh: destination cache entry
+ * @dev: network device
+ * @haddr: new hardware address
+ *
+ * Called by Address Resolution module to notify changes in address.
+ */
+void eth_header_cache_update(struct hh_cache *hh,
+			     const struct net_device *dev,
+			     const unsigned char *haddr)
+{
+	memcpy(((u8 *) hh->hh_data) + HH_DATA_OFF(sizeof(struct ethhdr)),
+	       haddr, ETH_ALEN);
+}
+EXPORT_SYMBOL(eth_header_cache_update);
+
+/**
+ * eth_header_parse_protocol - extract protocol from L2 header
+ * @skb: packet to extract protocol from
+ */
+__be16 eth_header_parse_protocol(const struct sk_buff *skb)
+{
+	const struct ethhdr *eth = eth_hdr(skb);
+
+	return eth->h_proto;
+}
+EXPORT_SYMBOL(eth_header_parse_protocol);
+
+/**
+ * eth_prepare_mac_addr_change - prepare for mac change
+ * @dev: network device
+ * @p: socket address
+ */
+int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
+{
+	struct sockaddr *addr = p;
+
+	if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
+		return -EBUSY;
+	if (!is_valid_ether_addr(addr->sa_data))
+		return -EADDRNOTAVAIL;
+	return 0;
+}
+EXPORT_SYMBOL(eth_prepare_mac_addr_change);
+
+/**
+ * eth_commit_mac_addr_change - commit mac change
+ * @dev: network device
+ * @p: socket address
+ */
+void eth_commit_mac_addr_change(struct net_device *dev, void *p)
+{
+	struct sockaddr *addr = p;
+
+	eth_hw_addr_set(dev, addr->sa_data);
+}
+EXPORT_SYMBOL(eth_commit_mac_addr_change);
+
+/**
+ * eth_mac_addr - set new Ethernet hardware address
+ * @dev: network device
+ * @p: socket address
+ *
+ * Change hardware address of device.
+ *
+ * This doesn't change hardware matching, so needs to be overridden
+ * for most real devices.
+ */
+int eth_mac_addr(struct net_device *dev, void *p)
+{
+	int ret;
+
+	ret = eth_prepare_mac_addr_change(dev, p);
+	if (ret < 0)
+		return ret;
+	eth_commit_mac_addr_change(dev, p);
+	return 0;
+}
+EXPORT_SYMBOL(eth_mac_addr);
+
+int eth_validate_addr(struct net_device *dev)
+{
+	if (!is_valid_ether_addr(dev->dev_addr))
+		return -EADDRNOTAVAIL;
+
+	return 0;
+}
+EXPORT_SYMBOL(eth_validate_addr);
+
+const struct header_ops eth_header_ops ____cacheline_aligned = {
+	.create		= eth_header,
+	.parse		= eth_header_parse,
+	.cache		= eth_header_cache,
+	.cache_update	= eth_header_cache_update,
+	.parse_protocol	= eth_header_parse_protocol,
+};
+
+/**
+ * ether_setup - setup Ethernet network device
+ * @dev: network device
+ *
+ * Fill in the fields of the device structure with Ethernet-generic values.
+ */
+void ether_setup(struct net_device *dev)
+{
+	dev->header_ops		= &eth_header_ops;
+	dev->type		= ARPHRD_ETHER;
+	dev->hard_header_len 	= ETH_HLEN;
+	dev->min_header_len	= ETH_HLEN;
+	dev->mtu		= ETH_DATA_LEN;
+	dev->min_mtu		= ETH_MIN_MTU;
+	dev->max_mtu		= ETH_DATA_LEN;
+	dev->addr_len		= ETH_ALEN;
+	dev->tx_queue_len	= DEFAULT_TX_QUEUE_LEN;
+	dev->flags		= IFF_BROADCAST|IFF_MULTICAST;
+	dev->priv_flags		|= IFF_TX_SKB_SHARING;
+
+	eth_broadcast_addr(dev->broadcast);
+
+}
+EXPORT_SYMBOL(ether_setup);
+
+/**
+ * alloc_etherdev_mqs - Allocates and sets up an Ethernet device
+ * @sizeof_priv: Size of additional driver-private structure to be allocated
+ *	for this Ethernet device
+ * @txqs: The number of TX queues this device has.
+ * @rxqs: The number of RX queues this device has.
+ *
+ * Fill in the fields of the device structure with Ethernet-generic
+ * values. Basically does everything except registering the device.
+ *
+ * Constructs a new net device, complete with a private data area of
+ * size (sizeof_priv).  A 32-byte (not bit) alignment is enforced for
+ * this private data area.
+ */
+
+struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
+				      unsigned int rxqs)
+{
+	return alloc_netdev_mqs(sizeof_priv, "eth%d", NET_NAME_ENUM,
+				ether_setup, txqs, rxqs);
+}
+EXPORT_SYMBOL(alloc_etherdev_mqs);
+
+ssize_t sysfs_format_mac(char *buf, const unsigned char *addr, int len)
+{
+	return sysfs_emit(buf, "%*phC\n", len, addr);
+}
+EXPORT_SYMBOL(sysfs_format_mac);
+
+struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb)
+{
+	const struct packet_offload *ptype;
+	unsigned int hlen, off_eth;
+	struct sk_buff *pp = NULL;
+	struct ethhdr *eh, *eh2;
+	struct sk_buff *p;
+	__be16 type;
+	int flush = 1;
+
+	off_eth = skb_gro_offset(skb);
+	hlen = off_eth + sizeof(*eh);
+	eh = skb_gro_header(skb, hlen, off_eth);
+	if (unlikely(!eh))
+		goto out;
+
+	flush = 0;
+
+	list_for_each_entry(p, head, list) {
+		if (!NAPI_GRO_CB(p)->same_flow)
+			continue;
+
+		eh2 = (struct ethhdr *)(p->data + off_eth);
+		if (compare_ether_header(eh, eh2)) {
+			NAPI_GRO_CB(p)->same_flow = 0;
+			continue;
+		}
+	}
+
+	type = eh->h_proto;
+
+	ptype = gro_find_receive_by_type(type);
+	if (ptype == NULL) {
+		flush = 1;
+		goto out;
+	}
+
+	skb_gro_pull(skb, sizeof(*eh));
+	skb_gro_postpull_rcsum(skb, eh, sizeof(*eh));
+
+	pp = indirect_call_gro_receive_inet(ptype->callbacks.gro_receive,
+					    ipv6_gro_receive, inet_gro_receive,
+					    head, skb);
+
+out:
+	skb_gro_flush_final(skb, pp, flush);
+
+	return pp;
+}
+EXPORT_SYMBOL(eth_gro_receive);
+
+int eth_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	struct ethhdr *eh = (struct ethhdr *)(skb->data + nhoff);
+	__be16 type = eh->h_proto;
+	struct packet_offload *ptype;
+	int err = -ENOSYS;
+
+	if (skb->encapsulation)
+		skb_set_inner_mac_header(skb, nhoff);
+
+	ptype = gro_find_complete_by_type(type);
+	if (ptype != NULL)
+		err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete,
+					 ipv6_gro_complete, inet_gro_complete,
+					 skb, nhoff + sizeof(*eh));
+
+	return err;
+}
+EXPORT_SYMBOL(eth_gro_complete);
+
+static struct packet_offload eth_packet_offload __read_mostly = {
+	.type = cpu_to_be16(ETH_P_TEB),
+	.priority = 10,
+	.callbacks = {
+		.gro_receive = eth_gro_receive,
+		.gro_complete = eth_gro_complete,
+	},
+};
+
+static int __init eth_offload_init(void)
+{
+	dev_add_offload(&eth_packet_offload);
+
+	return 0;
+}
+
+fs_initcall(eth_offload_init);
+
+unsigned char * __weak arch_get_platform_mac_address(void)
+{
+	return NULL;
+}
+
+int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)
+{
+	unsigned char *addr;
+	int ret;
+
+	ret = of_get_mac_address(dev->of_node, mac_addr);
+	if (!ret)
+		return 0;
+
+	addr = arch_get_platform_mac_address();
+	if (!addr)
+		return -ENODEV;
+
+	ether_addr_copy(mac_addr, addr);
+
+	return 0;
+}
+EXPORT_SYMBOL(eth_platform_get_mac_address);
+
+/**
+ * platform_get_ethdev_address - Set netdev's MAC address from a given device
+ * @dev:	Pointer to the device
+ * @netdev:	Pointer to netdev to write the address to
+ *
+ * Wrapper around eth_platform_get_mac_address() which writes the address
+ * directly to netdev->dev_addr.
+ */
+int platform_get_ethdev_address(struct device *dev, struct net_device *netdev)
+{
+	u8 addr[ETH_ALEN] __aligned(2);
+	int ret;
+
+	ret = eth_platform_get_mac_address(dev, addr);
+	if (!ret)
+		eth_hw_addr_set(netdev, addr);
+	return ret;
+}
+EXPORT_SYMBOL(platform_get_ethdev_address);
+
+/**
+ * nvmem_get_mac_address - Obtain the MAC address from an nvmem cell named
+ * 'mac-address' associated with given device.
+ *
+ * @dev:	Device with which the mac-address cell is associated.
+ * @addrbuf:	Buffer to which the MAC address will be copied on success.
+ *
+ * Returns 0 on success or a negative error number on failure.
+ */
+int nvmem_get_mac_address(struct device *dev, void *addrbuf)
+{
+	struct nvmem_cell *cell;
+	const void *mac;
+	size_t len;
+
+	cell = nvmem_cell_get(dev, "mac-address");
+	if (IS_ERR(cell))
+		return PTR_ERR(cell);
+
+	mac = nvmem_cell_read(cell, &len);
+	nvmem_cell_put(cell);
+
+	if (IS_ERR(mac))
+		return PTR_ERR(mac);
+
+	if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
+		kfree(mac);
+		return -EINVAL;
+	}
+
+	ether_addr_copy(addrbuf, mac);
+	kfree(mac);
+
+	return 0;
+}
+
+static int fwnode_get_mac_addr(struct fwnode_handle *fwnode,
+			       const char *name, char *addr)
+{
+	int ret;
+
+	ret = fwnode_property_read_u8_array(fwnode, name, addr, ETH_ALEN);
+	if (ret)
+		return ret;
+
+	if (!is_valid_ether_addr(addr))
+		return -EINVAL;
+	return 0;
+}
+
+/**
+ * fwnode_get_mac_address - Get the MAC from the firmware node
+ * @fwnode:	Pointer to the firmware node
+ * @addr:	Address of buffer to store the MAC in
+ *
+ * Search the firmware node for the best MAC address to use.  'mac-address' is
+ * checked first, because that is supposed to contain to "most recent" MAC
+ * address. If that isn't set, then 'local-mac-address' is checked next,
+ * because that is the default address.  If that isn't set, then the obsolete
+ * 'address' is checked, just in case we're using an old device tree.
+ *
+ * Note that the 'address' property is supposed to contain a virtual address of
+ * the register set, but some DTS files have redefined that property to be the
+ * MAC address.
+ *
+ * All-zero MAC addresses are rejected, because those could be properties that
+ * exist in the firmware tables, but were not updated by the firmware.  For
+ * example, the DTS could define 'mac-address' and 'local-mac-address', with
+ * zero MAC addresses.  Some older U-Boots only initialized 'local-mac-address'.
+ * In this case, the real MAC is in 'local-mac-address', and 'mac-address'
+ * exists but is all zeros.
+ */
+int fwnode_get_mac_address(struct fwnode_handle *fwnode, char *addr)
+{
+	if (!fwnode_get_mac_addr(fwnode, "mac-address", addr) ||
+	    !fwnode_get_mac_addr(fwnode, "local-mac-address", addr) ||
+	    !fwnode_get_mac_addr(fwnode, "address", addr))
+		return 0;
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL(fwnode_get_mac_address);
+
+/**
+ * device_get_mac_address - Get the MAC for a given device
+ * @dev:	Pointer to the device
+ * @addr:	Address of buffer to store the MAC in
+ */
+int device_get_mac_address(struct device *dev, char *addr)
+{
+	if (!fwnode_get_mac_address(dev_fwnode(dev), addr))
+		return 0;
+
+	return nvmem_get_mac_address(dev, addr);
+}
+EXPORT_SYMBOL(device_get_mac_address);
+
+/**
+ * device_get_ethdev_address - Set netdev's MAC address from a given device
+ * @dev:	Pointer to the device
+ * @netdev:	Pointer to netdev to write the address to
+ *
+ * Wrapper around device_get_mac_address() which writes the address
+ * directly to netdev->dev_addr.
+ */
+int device_get_ethdev_address(struct device *dev, struct net_device *netdev)
+{
+	u8 addr[ETH_ALEN];
+	int ret;
+
+	ret = device_get_mac_address(dev, addr);
+	if (!ret)
+		eth_hw_addr_set(netdev, addr);
+	return ret;
+}
+EXPORT_SYMBOL(device_get_ethdev_address);