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, 576 insertions, 0 deletions

diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
new file mode 100644
index 000000000..c69db6c90
--- /dev/null
+++ b/drivers/thermal/intel/intel_hfi.c
@@ -0,0 +1,576 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Hardware Feedback Interface Driver
+ *
+ * Copyright (c) 2021, Intel Corporation.
+ *
+ * Authors: Aubrey Li <aubrey.li@linux.intel.com>
+ *          Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
+ *
+ *
+ * The Hardware Feedback Interface provides a performance and energy efficiency
+ * capability information for each CPU in the system. Depending on the processor
+ * model, hardware may periodically update these capabilities as a result of
+ * changes in the operating conditions (e.g., power limits or thermal
+ * constraints). On other processor models, there is a single HFI update
+ * at boot.
+ *
+ * This file provides functionality to process HFI updates and relay these
+ * updates to userspace.
+ */
+
+#define pr_fmt(fmt)  "intel-hfi: " fmt
+
+#include <linux/bitops.h>
+#include <linux/cpufeature.h>
+#include <linux/cpumask.h>
+#include <linux/gfp.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/math.h>
+#include <linux/mutex.h>
+#include <linux/percpu-defs.h>
+#include <linux/printk.h>
+#include <linux/processor.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/topology.h>
+#include <linux/workqueue.h>
+
+#include <asm/msr.h>
+
+#include "intel_hfi.h"
+#include "thermal_interrupt.h"
+
+#include "../thermal_netlink.h"
+
+/* Hardware Feedback Interface MSR configuration bits */
+#define HW_FEEDBACK_PTR_VALID_BIT		BIT(0)
+#define HW_FEEDBACK_CONFIG_HFI_ENABLE_BIT	BIT(0)
+
+/* CPUID detection and enumeration definitions for HFI */
+
+#define CPUID_HFI_LEAF 6
+
+union hfi_capabilities {
+	struct {
+		u8	performance:1;
+		u8	energy_efficiency:1;
+		u8	__reserved:6;
+	} split;
+	u8 bits;
+};
+
+union cpuid6_edx {
+	struct {
+		union hfi_capabilities	capabilities;
+		u32			table_pages:4;
+		u32			__reserved:4;
+		s32			index:16;
+	} split;
+	u32 full;
+};
+
+/**
+ * struct hfi_cpu_data - HFI capabilities per CPU
+ * @perf_cap:		Performance capability
+ * @ee_cap:		Energy efficiency capability
+ *
+ * Capabilities of a logical processor in the HFI table. These capabilities are
+ * unitless.
+ */
+struct hfi_cpu_data {
+	u8	perf_cap;
+	u8	ee_cap;
+} __packed;
+
+/**
+ * struct hfi_hdr - Header of the HFI table
+ * @perf_updated:	Hardware updated performance capabilities
+ * @ee_updated:		Hardware updated energy efficiency capabilities
+ *
+ * Properties of the data in an HFI table.
+ */
+struct hfi_hdr {
+	u8	perf_updated;
+	u8	ee_updated;
+} __packed;
+
+/**
+ * struct hfi_instance - Representation of an HFI instance (i.e., a table)
+ * @local_table:	Base of the local copy of the HFI table
+ * @timestamp:		Timestamp of the last update of the local table.
+ *			Located at the base of the local table.
+ * @hdr:		Base address of the header of the local table
+ * @data:		Base address of the data of the local table
+ * @cpus:		CPUs represented in this HFI table instance
+ * @hw_table:		Pointer to the HFI table of this instance
+ * @update_work:	Delayed work to process HFI updates
+ * @table_lock:		Lock to protect acceses to the table of this instance
+ * @event_lock:		Lock to process HFI interrupts
+ *
+ * A set of parameters to parse and navigate a specific HFI table.
+ */
+struct hfi_instance {
+	union {
+		void			*local_table;
+		u64			*timestamp;
+	};
+	void			*hdr;
+	void			*data;
+	cpumask_var_t		cpus;
+	void			*hw_table;
+	struct delayed_work	update_work;
+	raw_spinlock_t		table_lock;
+	raw_spinlock_t		event_lock;
+};
+
+/**
+ * struct hfi_features - Supported HFI features
+ * @nr_table_pages:	Size of the HFI table in 4KB pages
+ * @cpu_stride:		Stride size to locate the capability data of a logical
+ *			processor within the table (i.e., row stride)
+ * @hdr_size:		Size of the table header
+ *
+ * Parameters and supported features that are common to all HFI instances
+ */
+struct hfi_features {
+	size_t		nr_table_pages;
+	unsigned int	cpu_stride;
+	unsigned int	hdr_size;
+};
+
+/**
+ * struct hfi_cpu_info - Per-CPU attributes to consume HFI data
+ * @index:		Row of this CPU in its HFI table
+ * @hfi_instance:	Attributes of the HFI table to which this CPU belongs
+ *
+ * Parameters to link a logical processor to an HFI table and a row within it.
+ */
+struct hfi_cpu_info {
+	s16			index;
+	struct hfi_instance	*hfi_instance;
+};
+
+static DEFINE_PER_CPU(struct hfi_cpu_info, hfi_cpu_info) = { .index = -1 };
+
+static int max_hfi_instances;
+static struct hfi_instance *hfi_instances;
+
+static struct hfi_features hfi_features;
+static DEFINE_MUTEX(hfi_instance_lock);
+
+static struct workqueue_struct *hfi_updates_wq;
+#define HFI_UPDATE_INTERVAL		HZ
+#define HFI_MAX_THERM_NOTIFY_COUNT	16
+
+static void get_hfi_caps(struct hfi_instance *hfi_instance,
+			 struct thermal_genl_cpu_caps *cpu_caps)
+{
+	int cpu, i = 0;
+
+	raw_spin_lock_irq(&hfi_instance->table_lock);
+	for_each_cpu(cpu, hfi_instance->cpus) {
+		struct hfi_cpu_data *caps;
+		s16 index;
+
+		index = per_cpu(hfi_cpu_info, cpu).index;
+		caps = hfi_instance->data + index * hfi_features.cpu_stride;
+		cpu_caps[i].cpu = cpu;
+
+		/*
+		 * Scale performance and energy efficiency to
+		 * the [0, 1023] interval that thermal netlink uses.
+		 */
+		cpu_caps[i].performance = caps->perf_cap << 2;
+		cpu_caps[i].efficiency = caps->ee_cap << 2;
+
+		++i;
+	}
+	raw_spin_unlock_irq(&hfi_instance->table_lock);
+}
+
+/*
+ * Call update_capabilities() when there are changes in the HFI table.
+ */
+static void update_capabilities(struct hfi_instance *hfi_instance)
+{
+	struct thermal_genl_cpu_caps *cpu_caps;
+	int i = 0, cpu_count;
+
+	/* CPUs may come online/offline while processing an HFI update. */
+	mutex_lock(&hfi_instance_lock);
+
+	cpu_count = cpumask_weight(hfi_instance->cpus);
+
+	/* No CPUs to report in this hfi_instance. */
+	if (!cpu_count)
+		goto out;
+
+	cpu_caps = kcalloc(cpu_count, sizeof(*cpu_caps), GFP_KERNEL);
+	if (!cpu_caps)
+		goto out;
+
+	get_hfi_caps(hfi_instance, cpu_caps);
+
+	if (cpu_count < HFI_MAX_THERM_NOTIFY_COUNT)
+		goto last_cmd;
+
+	/* Process complete chunks of HFI_MAX_THERM_NOTIFY_COUNT capabilities. */
+	for (i = 0;
+	     (i + HFI_MAX_THERM_NOTIFY_COUNT) <= cpu_count;
+	     i += HFI_MAX_THERM_NOTIFY_COUNT)
+		thermal_genl_cpu_capability_event(HFI_MAX_THERM_NOTIFY_COUNT,
+						  &cpu_caps[i]);
+
+	cpu_count = cpu_count - i;
+
+last_cmd:
+	/* Process the remaining capabilities if any. */
+	if (cpu_count)
+		thermal_genl_cpu_capability_event(cpu_count, &cpu_caps[i]);
+
+	kfree(cpu_caps);
+out:
+	mutex_unlock(&hfi_instance_lock);
+}
+
+static void hfi_update_work_fn(struct work_struct *work)
+{
+	struct hfi_instance *hfi_instance;
+
+	hfi_instance = container_of(to_delayed_work(work), struct hfi_instance,
+				    update_work);
+
+	update_capabilities(hfi_instance);
+}
+
+void intel_hfi_process_event(__u64 pkg_therm_status_msr_val)
+{
+	struct hfi_instance *hfi_instance;
+	int cpu = smp_processor_id();
+	struct hfi_cpu_info *info;
+	u64 new_timestamp, msr, hfi;
+
+	if (!pkg_therm_status_msr_val)
+		return;
+
+	info = &per_cpu(hfi_cpu_info, cpu);
+	if (!info)
+		return;
+
+	/*
+	 * A CPU is linked to its HFI instance before the thermal vector in the
+	 * local APIC is unmasked. Hence, info->hfi_instance cannot be NULL
+	 * when receiving an HFI event.
+	 */
+	hfi_instance = info->hfi_instance;
+	if (unlikely(!hfi_instance)) {
+		pr_debug("Received event on CPU %d but instance was null", cpu);
+		return;
+	}
+
+	/*
+	 * On most systems, all CPUs in the package receive a package-level
+	 * thermal interrupt when there is an HFI update. It is sufficient to
+	 * let a single CPU to acknowledge the update and queue work to
+	 * process it. The remaining CPUs can resume their work.
+	 */
+	if (!raw_spin_trylock(&hfi_instance->event_lock))
+		return;
+
+	rdmsrl(MSR_IA32_PACKAGE_THERM_STATUS, msr);
+	hfi = msr & PACKAGE_THERM_STATUS_HFI_UPDATED;
+	if (!hfi) {
+		raw_spin_unlock(&hfi_instance->event_lock);
+		return;
+	}
+
+	/*
+	 * Ack duplicate update. Since there is an active HFI
+	 * status from HW, it must be a new event, not a case
+	 * where a lagging CPU entered the locked region.
+	 */
+	new_timestamp = *(u64 *)hfi_instance->hw_table;
+	if (*hfi_instance->timestamp == new_timestamp) {
+		thermal_clear_package_intr_status(PACKAGE_LEVEL, PACKAGE_THERM_STATUS_HFI_UPDATED);
+		raw_spin_unlock(&hfi_instance->event_lock);
+		return;
+	}
+
+	raw_spin_lock(&hfi_instance->table_lock);
+
+	/*
+	 * Copy the updated table into our local copy. This includes the new
+	 * timestamp.
+	 */
+	memcpy(hfi_instance->local_table, hfi_instance->hw_table,
+	       hfi_features.nr_table_pages << PAGE_SHIFT);
+
+	/*
+	 * Let hardware know that we are done reading the HFI table and it is
+	 * free to update it again.
+	 */
+	thermal_clear_package_intr_status(PACKAGE_LEVEL, PACKAGE_THERM_STATUS_HFI_UPDATED);
+
+	raw_spin_unlock(&hfi_instance->table_lock);
+	raw_spin_unlock(&hfi_instance->event_lock);
+
+	queue_delayed_work(hfi_updates_wq, &hfi_instance->update_work,
+			   HFI_UPDATE_INTERVAL);
+}
+
+static void init_hfi_cpu_index(struct hfi_cpu_info *info)
+{
+	union cpuid6_edx edx;
+
+	/* Do not re-read @cpu's index if it has already been initialized. */
+	if (info->index > -1)
+		return;
+
+	edx.full = cpuid_edx(CPUID_HFI_LEAF);
+	info->index = edx.split.index;
+}
+
+/*
+ * The format of the HFI table depends on the number of capabilities that the
+ * hardware supports. Keep a data structure to navigate the table.
+ */
+static void init_hfi_instance(struct hfi_instance *hfi_instance)
+{
+	/* The HFI header is below the time-stamp. */
+	hfi_instance->hdr = hfi_instance->local_table +
+			    sizeof(*hfi_instance->timestamp);
+
+	/* The HFI data starts below the header. */
+	hfi_instance->data = hfi_instance->hdr + hfi_features.hdr_size;
+}
+
+/**
+ * intel_hfi_online() - Enable HFI on @cpu
+ * @cpu:	CPU in which the HFI will be enabled
+ *
+ * Enable the HFI to be used in @cpu. The HFI is enabled at the die/package
+ * level. The first CPU in the die/package to come online does the full HFI
+ * initialization. Subsequent CPUs will just link themselves to the HFI
+ * instance of their die/package.
+ *
+ * This function is called before enabling the thermal vector in the local APIC
+ * in order to ensure that @cpu has an associated HFI instance when it receives
+ * an HFI event.
+ */
+void intel_hfi_online(unsigned int cpu)
+{
+	struct hfi_instance *hfi_instance;
+	struct hfi_cpu_info *info;
+	phys_addr_t hw_table_pa;
+	u64 msr_val;
+	u16 die_id;
+
+	/* Nothing to do if hfi_instances are missing. */
+	if (!hfi_instances)
+		return;
+
+	/*
+	 * Link @cpu to the HFI instance of its package/die. It does not
+	 * matter whether the instance has been initialized.
+	 */
+	info = &per_cpu(hfi_cpu_info, cpu);
+	die_id = topology_logical_die_id(cpu);
+	hfi_instance = info->hfi_instance;
+	if (!hfi_instance) {
+		if (die_id >= max_hfi_instances)
+			return;
+
+		hfi_instance = &hfi_instances[die_id];
+		info->hfi_instance = hfi_instance;
+	}
+
+	init_hfi_cpu_index(info);
+
+	/*
+	 * Now check if the HFI instance of the package/die of @cpu has been
+	 * initialized (by checking its header). In such case, all we have to
+	 * do is to add @cpu to this instance's cpumask.
+	 */
+	mutex_lock(&hfi_instance_lock);
+	if (hfi_instance->hdr) {
+		cpumask_set_cpu(cpu, hfi_instance->cpus);
+		goto unlock;
+	}
+
+	/*
+	 * Hardware is programmed with the physical address of the first page
+	 * frame of the table. Hence, the allocated memory must be page-aligned.
+	 */
+	hfi_instance->hw_table = alloc_pages_exact(hfi_features.nr_table_pages,
+						   GFP_KERNEL | __GFP_ZERO);
+	if (!hfi_instance->hw_table)
+		goto unlock;
+
+	hw_table_pa = virt_to_phys(hfi_instance->hw_table);
+
+	/*
+	 * Allocate memory to keep a local copy of the table that
+	 * hardware generates.
+	 */
+	hfi_instance->local_table = kzalloc(hfi_features.nr_table_pages << PAGE_SHIFT,
+					    GFP_KERNEL);
+	if (!hfi_instance->local_table)
+		goto free_hw_table;
+
+	/*
+	 * Program the address of the feedback table of this die/package. On
+	 * some processors, hardware remembers the old address of the HFI table
+	 * even after having been reprogrammed and re-enabled. Thus, do not free
+	 * the pages allocated for the table or reprogram the hardware with a
+	 * new base address. Namely, program the hardware only once.
+	 */
+	msr_val = hw_table_pa | HW_FEEDBACK_PTR_VALID_BIT;
+	wrmsrl(MSR_IA32_HW_FEEDBACK_PTR, msr_val);
+
+	init_hfi_instance(hfi_instance);
+
+	INIT_DELAYED_WORK(&hfi_instance->update_work, hfi_update_work_fn);
+	raw_spin_lock_init(&hfi_instance->table_lock);
+	raw_spin_lock_init(&hfi_instance->event_lock);
+
+	cpumask_set_cpu(cpu, hfi_instance->cpus);
+
+	/*
+	 * Enable the hardware feedback interface and never disable it. See
+	 * comment on programming the address of the table.
+	 */
+	rdmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);
+	msr_val |= HW_FEEDBACK_CONFIG_HFI_ENABLE_BIT;
+	wrmsrl(MSR_IA32_HW_FEEDBACK_CONFIG, msr_val);
+
+unlock:
+	mutex_unlock(&hfi_instance_lock);
+	return;
+
+free_hw_table:
+	free_pages_exact(hfi_instance->hw_table, hfi_features.nr_table_pages);
+	goto unlock;
+}
+
+/**
+ * intel_hfi_offline() - Disable HFI on @cpu
+ * @cpu:	CPU in which the HFI will be disabled
+ *
+ * Remove @cpu from those covered by its HFI instance.
+ *
+ * On some processors, hardware remembers previous programming settings even
+ * after being reprogrammed. Thus, keep HFI enabled even if all CPUs in the
+ * die/package of @cpu are offline. See note in intel_hfi_online().
+ */
+void intel_hfi_offline(unsigned int cpu)
+{
+	struct hfi_cpu_info *info = &per_cpu(hfi_cpu_info, cpu);
+	struct hfi_instance *hfi_instance;
+
+	/*
+	 * Check if @cpu as an associated, initialized (i.e., with a non-NULL
+	 * header). Also, HFI instances are only initialized if X86_FEATURE_HFI
+	 * is present.
+	 */
+	hfi_instance = info->hfi_instance;
+	if (!hfi_instance)
+		return;
+
+	if (!hfi_instance->hdr)
+		return;
+
+	mutex_lock(&hfi_instance_lock);
+	cpumask_clear_cpu(cpu, hfi_instance->cpus);
+	mutex_unlock(&hfi_instance_lock);
+}
+
+static __init int hfi_parse_features(void)
+{
+	unsigned int nr_capabilities;
+	union cpuid6_edx edx;
+
+	if (!boot_cpu_has(X86_FEATURE_HFI))
+		return -ENODEV;
+
+	/*
+	 * If we are here we know that CPUID_HFI_LEAF exists. Parse the
+	 * supported capabilities and the size of the HFI table.
+	 */
+	edx.full = cpuid_edx(CPUID_HFI_LEAF);
+
+	if (!edx.split.capabilities.split.performance) {
+		pr_debug("Performance reporting not supported! Not using HFI\n");
+		return -ENODEV;
+	}
+
+	/*
+	 * The number of supported capabilities determines the number of
+	 * columns in the HFI table. Exclude the reserved bits.
+	 */
+	edx.split.capabilities.split.__reserved = 0;
+	nr_capabilities = hweight8(edx.split.capabilities.bits);
+
+	/* The number of 4KB pages required by the table */
+	hfi_features.nr_table_pages = edx.split.table_pages + 1;
+
+	/*
+	 * The header contains change indications for each supported feature.
+	 * The size of the table header is rounded up to be a multiple of 8
+	 * bytes.
+	 */
+	hfi_features.hdr_size = DIV_ROUND_UP(nr_capabilities, 8) * 8;
+
+	/*
+	 * Data of each logical processor is also rounded up to be a multiple
+	 * of 8 bytes.
+	 */
+	hfi_features.cpu_stride = DIV_ROUND_UP(nr_capabilities, 8) * 8;
+
+	return 0;
+}
+
+void __init intel_hfi_init(void)
+{
+	struct hfi_instance *hfi_instance;
+	int i, j;
+
+	if (hfi_parse_features())
+		return;
+
+	/* There is one HFI instance per die/package. */
+	max_hfi_instances = topology_max_packages() *
+			    topology_max_die_per_package();
+
+	/*
+	 * This allocation may fail. CPU hotplug callbacks must check
+	 * for a null pointer.
+	 */
+	hfi_instances = kcalloc(max_hfi_instances, sizeof(*hfi_instances),
+				GFP_KERNEL);
+	if (!hfi_instances)
+		return;
+
+	for (i = 0; i < max_hfi_instances; i++) {
+		hfi_instance = &hfi_instances[i];
+		if (!zalloc_cpumask_var(&hfi_instance->cpus, GFP_KERNEL))
+			goto err_nomem;
+	}
+
+	hfi_updates_wq = create_singlethread_workqueue("hfi-updates");
+	if (!hfi_updates_wq)
+		goto err_nomem;
+
+	return;
+
+err_nomem:
+	for (j = 0; j < i; ++j) {
+		hfi_instance = &hfi_instances[j];
+		free_cpumask_var(hfi_instance->cpus);
+	}
+
+	kfree(hfi_instances);
+	hfi_instances = NULL;
+}