Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 525 insertions, 0 deletions

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
new file mode 100644
index 000000000..05e791241
--- /dev/null
+++ b/kernel/trace/trace_event_perf.c
@@ -0,0 +1,525 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace event based perf event profiling/tracing
+ *
+ * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra
+ * Copyright (C) 2009-2010 Frederic Weisbecker <fweisbec@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kprobes.h>
+#include <linux/security.h>
+#include "trace.h"
+#include "trace_probe.h"
+
+static char __percpu *perf_trace_buf[PERF_NR_CONTEXTS];
+
+/*
+ * Force it to be aligned to unsigned long to avoid misaligned accesses
+ * surprises
+ */
+typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
+	perf_trace_t;
+
+/* Count the events in use (per event id, not per instance) */
+static int	total_ref_count;
+
+static int perf_trace_event_perm(struct trace_event_call *tp_event,
+				 struct perf_event *p_event)
+{
+	int ret;
+
+	if (tp_event->perf_perm) {
+		ret = tp_event->perf_perm(tp_event, p_event);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * We checked and allowed to create parent,
+	 * allow children without checking.
+	 */
+	if (p_event->parent)
+		return 0;
+
+	/*
+	 * It's ok to check current process (owner) permissions in here,
+	 * because code below is called only via perf_event_open syscall.
+	 */
+
+	/* The ftrace function trace is allowed only for root. */
+	if (ftrace_event_is_function(tp_event)) {
+		ret = perf_allow_tracepoint(&p_event->attr);
+		if (ret)
+			return ret;
+
+		if (!is_sampling_event(p_event))
+			return 0;
+
+		/*
+		 * We don't allow user space callchains for  function trace
+		 * event, due to issues with page faults while tracing page
+		 * fault handler and its overall trickiness nature.
+		 */
+		if (!p_event->attr.exclude_callchain_user)
+			return -EINVAL;
+
+		/*
+		 * Same reason to disable user stack dump as for user space
+		 * callchains above.
+		 */
+		if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER)
+			return -EINVAL;
+	}
+
+	/* No tracing, just counting, so no obvious leak */
+	if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))
+		return 0;
+
+	/* Some events are ok to be traced by non-root users... */
+	if (p_event->attach_state == PERF_ATTACH_TASK) {
+		if (tp_event->flags & TRACE_EVENT_FL_CAP_ANY)
+			return 0;
+	}
+
+	/*
+	 * ...otherwise raw tracepoint data can be a severe data leak,
+	 * only allow root to have these.
+	 */
+	ret = perf_allow_tracepoint(&p_event->attr);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int perf_trace_event_reg(struct trace_event_call *tp_event,
+				struct perf_event *p_event)
+{
+	struct hlist_head __percpu *list;
+	int ret = -ENOMEM;
+	int cpu;
+
+	p_event->tp_event = tp_event;
+	if (tp_event->perf_refcount++ > 0)
+		return 0;
+
+	list = alloc_percpu(struct hlist_head);
+	if (!list)
+		goto fail;
+
+	for_each_possible_cpu(cpu)
+		INIT_HLIST_HEAD(per_cpu_ptr(list, cpu));
+
+	tp_event->perf_events = list;
+
+	if (!total_ref_count) {
+		char __percpu *buf;
+		int i;
+
+		for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+			buf = (char __percpu *)alloc_percpu(perf_trace_t);
+			if (!buf)
+				goto fail;
+
+			perf_trace_buf[i] = buf;
+		}
+	}
+
+	ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER, NULL);
+	if (ret)
+		goto fail;
+
+	total_ref_count++;
+	return 0;
+
+fail:
+	if (!total_ref_count) {
+		int i;
+
+		for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+			free_percpu(perf_trace_buf[i]);
+			perf_trace_buf[i] = NULL;
+		}
+	}
+
+	if (!--tp_event->perf_refcount) {
+		free_percpu(tp_event->perf_events);
+		tp_event->perf_events = NULL;
+	}
+
+	return ret;
+}
+
+static void perf_trace_event_unreg(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+	int i;
+
+	if (--tp_event->perf_refcount > 0)
+		return;
+
+	tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER, NULL);
+
+	/*
+	 * Ensure our callback won't be called anymore. The buffers
+	 * will be freed after that.
+	 */
+	tracepoint_synchronize_unregister();
+
+	free_percpu(tp_event->perf_events);
+	tp_event->perf_events = NULL;
+
+	if (!--total_ref_count) {
+		for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+			free_percpu(perf_trace_buf[i]);
+			perf_trace_buf[i] = NULL;
+		}
+	}
+}
+
+static int perf_trace_event_open(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+	return tp_event->class->reg(tp_event, TRACE_REG_PERF_OPEN, p_event);
+}
+
+static void perf_trace_event_close(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+	tp_event->class->reg(tp_event, TRACE_REG_PERF_CLOSE, p_event);
+}
+
+static int perf_trace_event_init(struct trace_event_call *tp_event,
+				 struct perf_event *p_event)
+{
+	int ret;
+
+	ret = perf_trace_event_perm(tp_event, p_event);
+	if (ret)
+		return ret;
+
+	ret = perf_trace_event_reg(tp_event, p_event);
+	if (ret)
+		return ret;
+
+	ret = perf_trace_event_open(p_event);
+	if (ret) {
+		perf_trace_event_unreg(p_event);
+		return ret;
+	}
+
+	return 0;
+}
+
+int perf_trace_init(struct perf_event *p_event)
+{
+	struct trace_event_call *tp_event;
+	u64 event_id = p_event->attr.config;
+	int ret = -EINVAL;
+
+	mutex_lock(&event_mutex);
+	list_for_each_entry(tp_event, &ftrace_events, list) {
+		if (tp_event->event.type == event_id &&
+		    tp_event->class && tp_event->class->reg &&
+		    trace_event_try_get_ref(tp_event)) {
+			ret = perf_trace_event_init(tp_event, p_event);
+			if (ret)
+				trace_event_put_ref(tp_event);
+			break;
+		}
+	}
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+void perf_trace_destroy(struct perf_event *p_event)
+{
+	mutex_lock(&event_mutex);
+	perf_trace_event_close(p_event);
+	perf_trace_event_unreg(p_event);
+	trace_event_put_ref(p_event->tp_event);
+	mutex_unlock(&event_mutex);
+}
+
+#ifdef CONFIG_KPROBE_EVENTS
+int perf_kprobe_init(struct perf_event *p_event, bool is_retprobe)
+{
+	int ret;
+	char *func = NULL;
+	struct trace_event_call *tp_event;
+
+	if (p_event->attr.kprobe_func) {
+		func = strndup_user(u64_to_user_ptr(p_event->attr.kprobe_func),
+				    KSYM_NAME_LEN);
+		if (IS_ERR(func)) {
+			ret = PTR_ERR(func);
+			return (ret == -EINVAL) ? -E2BIG : ret;
+		}
+
+		if (func[0] == '\0') {
+			kfree(func);
+			func = NULL;
+		}
+	}
+
+	tp_event = create_local_trace_kprobe(
+		func, (void *)(unsigned long)(p_event->attr.kprobe_addr),
+		p_event->attr.probe_offset, is_retprobe);
+	if (IS_ERR(tp_event)) {
+		ret = PTR_ERR(tp_event);
+		goto out;
+	}
+
+	mutex_lock(&event_mutex);
+	ret = perf_trace_event_init(tp_event, p_event);
+	if (ret)
+		destroy_local_trace_kprobe(tp_event);
+	mutex_unlock(&event_mutex);
+out:
+	kfree(func);
+	return ret;
+}
+
+void perf_kprobe_destroy(struct perf_event *p_event)
+{
+	mutex_lock(&event_mutex);
+	perf_trace_event_close(p_event);
+	perf_trace_event_unreg(p_event);
+	trace_event_put_ref(p_event->tp_event);
+	mutex_unlock(&event_mutex);
+
+	destroy_local_trace_kprobe(p_event->tp_event);
+}
+#endif /* CONFIG_KPROBE_EVENTS */
+
+#ifdef CONFIG_UPROBE_EVENTS
+int perf_uprobe_init(struct perf_event *p_event,
+		     unsigned long ref_ctr_offset, bool is_retprobe)
+{
+	int ret;
+	char *path = NULL;
+	struct trace_event_call *tp_event;
+
+	if (!p_event->attr.uprobe_path)
+		return -EINVAL;
+
+	path = strndup_user(u64_to_user_ptr(p_event->attr.uprobe_path),
+			    PATH_MAX);
+	if (IS_ERR(path)) {
+		ret = PTR_ERR(path);
+		return (ret == -EINVAL) ? -E2BIG : ret;
+	}
+	if (path[0] == '\0') {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	tp_event = create_local_trace_uprobe(path, p_event->attr.probe_offset,
+					     ref_ctr_offset, is_retprobe);
+	if (IS_ERR(tp_event)) {
+		ret = PTR_ERR(tp_event);
+		goto out;
+	}
+
+	/*
+	 * local trace_uprobe need to hold event_mutex to call
+	 * uprobe_buffer_enable() and uprobe_buffer_disable().
+	 * event_mutex is not required for local trace_kprobes.
+	 */
+	mutex_lock(&event_mutex);
+	ret = perf_trace_event_init(tp_event, p_event);
+	if (ret)
+		destroy_local_trace_uprobe(tp_event);
+	mutex_unlock(&event_mutex);
+out:
+	kfree(path);
+	return ret;
+}
+
+void perf_uprobe_destroy(struct perf_event *p_event)
+{
+	mutex_lock(&event_mutex);
+	perf_trace_event_close(p_event);
+	perf_trace_event_unreg(p_event);
+	trace_event_put_ref(p_event->tp_event);
+	mutex_unlock(&event_mutex);
+	destroy_local_trace_uprobe(p_event->tp_event);
+}
+#endif /* CONFIG_UPROBE_EVENTS */
+
+int perf_trace_add(struct perf_event *p_event, int flags)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+
+	if (!(flags & PERF_EF_START))
+		p_event->hw.state = PERF_HES_STOPPED;
+
+	/*
+	 * If TRACE_REG_PERF_ADD returns false; no custom action was performed
+	 * and we need to take the default action of enqueueing our event on
+	 * the right per-cpu hlist.
+	 */
+	if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event)) {
+		struct hlist_head __percpu *pcpu_list;
+		struct hlist_head *list;
+
+		pcpu_list = tp_event->perf_events;
+		if (WARN_ON_ONCE(!pcpu_list))
+			return -EINVAL;
+
+		list = this_cpu_ptr(pcpu_list);
+		hlist_add_head_rcu(&p_event->hlist_entry, list);
+	}
+
+	return 0;
+}
+
+void perf_trace_del(struct perf_event *p_event, int flags)
+{
+	struct trace_event_call *tp_event = p_event->tp_event;
+
+	/*
+	 * If TRACE_REG_PERF_DEL returns false; no custom action was performed
+	 * and we need to take the default action of dequeueing our event from
+	 * the right per-cpu hlist.
+	 */
+	if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_DEL, p_event))
+		hlist_del_rcu(&p_event->hlist_entry);
+}
+
+void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp)
+{
+	char *raw_data;
+	int rctx;
+
+	BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
+
+	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
+		      "perf buffer not large enough, wanted %d, have %d",
+		      size, PERF_MAX_TRACE_SIZE))
+		return NULL;
+
+	*rctxp = rctx = perf_swevent_get_recursion_context();
+	if (rctx < 0)
+		return NULL;
+
+	if (regs)
+		*regs = this_cpu_ptr(&__perf_regs[rctx]);
+	raw_data = this_cpu_ptr(perf_trace_buf[rctx]);
+
+	/* zero the dead bytes from align to not leak stack to user */
+	memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
+	return raw_data;
+}
+EXPORT_SYMBOL_GPL(perf_trace_buf_alloc);
+NOKPROBE_SYMBOL(perf_trace_buf_alloc);
+
+void perf_trace_buf_update(void *record, u16 type)
+{
+	struct trace_entry *entry = record;
+
+	tracing_generic_entry_update(entry, type, tracing_gen_ctx());
+}
+NOKPROBE_SYMBOL(perf_trace_buf_update);
+
+#ifdef CONFIG_FUNCTION_TRACER
+static void
+perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
+			  struct ftrace_ops *ops,  struct ftrace_regs *fregs)
+{
+	struct ftrace_entry *entry;
+	struct perf_event *event;
+	struct hlist_head head;
+	struct pt_regs regs;
+	int rctx;
+	int bit;
+
+	if (!rcu_is_watching())
+		return;
+
+	bit = ftrace_test_recursion_trylock(ip, parent_ip);
+	if (bit < 0)
+		return;
+
+	if ((unsigned long)ops->private != smp_processor_id())
+		goto out;
+
+	event = container_of(ops, struct perf_event, ftrace_ops);
+
+	/*
+	 * @event->hlist entry is NULL (per INIT_HLIST_NODE), and all
+	 * the perf code does is hlist_for_each_entry_rcu(), so we can
+	 * get away with simply setting the @head.first pointer in order
+	 * to create a singular list.
+	 */
+	head.first = &event->hlist_entry;
+
+#define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \
+		    sizeof(u64)) - sizeof(u32))
+
+	BUILD_BUG_ON(ENTRY_SIZE > PERF_MAX_TRACE_SIZE);
+
+	memset(&regs, 0, sizeof(regs));
+	perf_fetch_caller_regs(&regs);
+
+	entry = perf_trace_buf_alloc(ENTRY_SIZE, NULL, &rctx);
+	if (!entry)
+		goto out;
+
+	entry->ip = ip;
+	entry->parent_ip = parent_ip;
+	perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN,
+			      1, &regs, &head, NULL);
+
+out:
+	ftrace_test_recursion_unlock(bit);
+#undef ENTRY_SIZE
+}
+
+static int perf_ftrace_function_register(struct perf_event *event)
+{
+	struct ftrace_ops *ops = &event->ftrace_ops;
+
+	ops->func    = perf_ftrace_function_call;
+	ops->private = (void *)(unsigned long)nr_cpu_ids;
+
+	return register_ftrace_function(ops);
+}
+
+static int perf_ftrace_function_unregister(struct perf_event *event)
+{
+	struct ftrace_ops *ops = &event->ftrace_ops;
+	int ret = unregister_ftrace_function(ops);
+	ftrace_free_filter(ops);
+	return ret;
+}
+
+int perf_ftrace_event_register(struct trace_event_call *call,
+			       enum trace_reg type, void *data)
+{
+	struct perf_event *event = data;
+
+	switch (type) {
+	case TRACE_REG_REGISTER:
+	case TRACE_REG_UNREGISTER:
+		break;
+	case TRACE_REG_PERF_REGISTER:
+	case TRACE_REG_PERF_UNREGISTER:
+		return 0;
+	case TRACE_REG_PERF_OPEN:
+		return perf_ftrace_function_register(data);
+	case TRACE_REG_PERF_CLOSE:
+		return perf_ftrace_function_unregister(data);
+	case TRACE_REG_PERF_ADD:
+		event->ftrace_ops.private = (void *)(unsigned long)smp_processor_id();
+		return 1;
+	case TRACE_REG_PERF_DEL:
+		event->ftrace_ops.private = (void *)(unsigned long)nr_cpu_ids;
+		return 1;
+	}
+
+	return -EINVAL;
+}
+#endif /* CONFIG_FUNCTION_TRACER */