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().
  ...

5 files changed, 454 insertions, 0 deletions

diff --git a/Documentation/core-api/irq/concepts.rst b/Documentation/core-api/irq/concepts.rst
new file mode 100644
index 000000000..4273806a6
--- /dev/null
+++ b/Documentation/core-api/irq/concepts.rst
@@ -0,0 +1,24 @@
+===============
+What is an IRQ?
+===============
+
+An IRQ is an interrupt request from a device.
+Currently they can come in over a pin, or over a packet.
+Several devices may be connected to the same pin thus
+sharing an IRQ.
+
+An IRQ number is a kernel identifier used to talk about a hardware
+interrupt source.  Typically this is an index into the global irq_desc
+array, but except for what linux/interrupt.h implements the details
+are architecture specific.
+
+An IRQ number is an enumeration of the possible interrupt sources on a
+machine.  Typically what is enumerated is the number of input pins on
+all of the interrupt controller in the system.  In the case of ISA
+what is enumerated are the 16 input pins on the two i8259 interrupt
+controllers.
+
+Architectures can assign additional meaning to the IRQ numbers, and
+are encouraged to in the case  where there is any manual configuration
+of the hardware involved.  The ISA IRQs are a classic example of
+assigning this kind of additional meaning.
diff --git a/Documentation/core-api/irq/index.rst b/Documentation/core-api/irq/index.rst
new file mode 100644
index 000000000..0d65d11e5
--- /dev/null
+++ b/Documentation/core-api/irq/index.rst
@@ -0,0 +1,11 @@
+====
+IRQs
+====
+
+.. toctree::
+   :maxdepth: 1
+
+   concepts
+   irq-affinity
+   irq-domain
+   irqflags-tracing
diff --git a/Documentation/core-api/irq/irq-affinity.rst b/Documentation/core-api/irq/irq-affinity.rst
new file mode 100644
index 000000000..29da50008
--- /dev/null
+++ b/Documentation/core-api/irq/irq-affinity.rst
@@ -0,0 +1,70 @@
+================
+SMP IRQ affinity
+================
+
+ChangeLog:
+	- Started by Ingo Molnar <mingo@redhat.com>
+	- Update by Max Krasnyansky <maxk@qualcomm.com>
+
+
+/proc/irq/IRQ#/smp_affinity and /proc/irq/IRQ#/smp_affinity_list specify
+which target CPUs are permitted for a given IRQ source.  It's a bitmask
+(smp_affinity) or cpu list (smp_affinity_list) of allowed CPUs.  It's not
+allowed to turn off all CPUs, and if an IRQ controller does not support
+IRQ affinity then the value will not change from the default of all cpus.
+
+/proc/irq/default_smp_affinity specifies default affinity mask that applies
+to all non-active IRQs. Once IRQ is allocated/activated its affinity bitmask
+will be set to the default mask. It can then be changed as described above.
+Default mask is 0xffffffff.
+
+Here is an example of restricting IRQ44 (eth1) to CPU0-3 then restricting
+it to CPU4-7 (this is an 8-CPU SMP box)::
+
+	[root@moon 44]# cd /proc/irq/44
+	[root@moon 44]# cat smp_affinity
+	ffffffff
+
+	[root@moon 44]# echo 0f > smp_affinity
+	[root@moon 44]# cat smp_affinity
+	0000000f
+	[root@moon 44]# ping -f h
+	PING hell (195.4.7.3): 56 data bytes
+	...
+	--- hell ping statistics ---
+	6029 packets transmitted, 6027 packets received, 0% packet loss
+	round-trip min/avg/max = 0.1/0.1/0.4 ms
+	[root@moon 44]# cat /proc/interrupts | grep 'CPU\|44:'
+		CPU0       CPU1       CPU2       CPU3      CPU4       CPU5        CPU6       CPU7
+	44:       1068       1785       1785       1783         0          0           0         0    IO-APIC-level  eth1
+
+As can be seen from the line above IRQ44 was delivered only to the first four
+processors (0-3).
+Now lets restrict that IRQ to CPU(4-7).
+
+::
+
+	[root@moon 44]# echo f0 > smp_affinity
+	[root@moon 44]# cat smp_affinity
+	000000f0
+	[root@moon 44]# ping -f h
+	PING hell (195.4.7.3): 56 data bytes
+	..
+	--- hell ping statistics ---
+	2779 packets transmitted, 2777 packets received, 0% packet loss
+	round-trip min/avg/max = 0.1/0.5/585.4 ms
+	[root@moon 44]# cat /proc/interrupts |  'CPU\|44:'
+		CPU0       CPU1       CPU2       CPU3      CPU4       CPU5        CPU6       CPU7
+	44:       1068       1785       1785       1783      1784       1069        1070       1069   IO-APIC-level  eth1
+
+This time around IRQ44 was delivered only to the last four processors.
+i.e counters for the CPU0-3 did not change.
+
+Here is an example of limiting that same irq (44) to cpus 1024 to 1031::
+
+	[root@moon 44]# echo 1024-1031 > smp_affinity_list
+	[root@moon 44]# cat smp_affinity_list
+	1024-1031
+
+Note that to do this with a bitmask would require 32 bitmasks of zero
+to follow the pertinent one.
diff --git a/Documentation/core-api/irq/irq-domain.rst b/Documentation/core-api/irq/irq-domain.rst
new file mode 100644
index 000000000..f88a6ee67
--- /dev/null
+++ b/Documentation/core-api/irq/irq-domain.rst
@@ -0,0 +1,297 @@
+===============================================
+The irq_domain interrupt number mapping library
+===============================================
+
+The current design of the Linux kernel uses a single large number
+space where each separate IRQ source is assigned a different number.
+This is simple when there is only one interrupt controller, but in
+systems with multiple interrupt controllers the kernel must ensure
+that each one gets assigned non-overlapping allocations of Linux
+IRQ numbers.
+
+The number of interrupt controllers registered as unique irqchips
+show a rising tendency: for example subdrivers of different kinds
+such as GPIO controllers avoid reimplementing identical callback
+mechanisms as the IRQ core system by modelling their interrupt
+handlers as irqchips, i.e. in effect cascading interrupt controllers.
+
+Here the interrupt number loose all kind of correspondence to
+hardware interrupt numbers: whereas in the past, IRQ numbers could
+be chosen so they matched the hardware IRQ line into the root
+interrupt controller (i.e. the component actually fireing the
+interrupt line to the CPU) nowadays this number is just a number.
+
+For this reason we need a mechanism to separate controller-local
+interrupt numbers, called hardware irq's, from Linux IRQ numbers.
+
+The irq_alloc_desc*() and irq_free_desc*() APIs provide allocation of
+irq numbers, but they don't provide any support for reverse mapping of
+the controller-local IRQ (hwirq) number into the Linux IRQ number
+space.
+
+The irq_domain library adds mapping between hwirq and IRQ numbers on
+top of the irq_alloc_desc*() API.  An irq_domain to manage mapping is
+preferred over interrupt controller drivers open coding their own
+reverse mapping scheme.
+
+irq_domain also implements translation from an abstract irq_fwspec
+structure to hwirq numbers (Device Tree and ACPI GSI so far), and can
+be easily extended to support other IRQ topology data sources.
+
+irq_domain usage
+================
+
+An interrupt controller driver creates and registers an irq_domain by
+calling one of the irq_domain_add_*() or irq_domain_create_*() functions
+(each mapping method has a different allocator function, more on that later).
+The function will return a pointer to the irq_domain on success. The caller
+must provide the allocator function with an irq_domain_ops structure.
+
+In most cases, the irq_domain will begin empty without any mappings
+between hwirq and IRQ numbers.  Mappings are added to the irq_domain
+by calling irq_create_mapping() which accepts the irq_domain and a
+hwirq number as arguments.  If a mapping for the hwirq doesn't already
+exist then it will allocate a new Linux irq_desc, associate it with
+the hwirq, and call the .map() callback so the driver can perform any
+required hardware setup.
+
+Once a mapping has been established, it can be retrieved or used via a
+variety of methods:
+
+- irq_resolve_mapping() returns a pointer to the irq_desc structure
+  for a given domain and hwirq number, and NULL if there was no
+  mapping.
+- irq_find_mapping() returns a Linux IRQ number for a given domain and
+  hwirq number, and 0 if there was no mapping
+- irq_linear_revmap() is now identical to irq_find_mapping(), and is
+  deprecated
+- generic_handle_domain_irq() handles an interrupt described by a
+  domain and a hwirq number
+
+Note that irq domain lookups must happen in contexts that are
+compatible with a RCU read-side critical section.
+
+The irq_create_mapping() function must be called *at least once*
+before any call to irq_find_mapping(), lest the descriptor will not
+be allocated.
+
+If the driver has the Linux IRQ number or the irq_data pointer, and
+needs to know the associated hwirq number (such as in the irq_chip
+callbacks) then it can be directly obtained from irq_data->hwirq.
+
+Types of irq_domain mappings
+============================
+
+There are several mechanisms available for reverse mapping from hwirq
+to Linux irq, and each mechanism uses a different allocation function.
+Which reverse map type should be used depends on the use case.  Each
+of the reverse map types are described below:
+
+Linear
+------
+
+::
+
+	irq_domain_add_linear()
+	irq_domain_create_linear()
+
+The linear reverse map maintains a fixed size table indexed by the
+hwirq number.  When a hwirq is mapped, an irq_desc is allocated for
+the hwirq, and the IRQ number is stored in the table.
+
+The Linear map is a good choice when the maximum number of hwirqs is
+fixed and a relatively small number (~ < 256).  The advantages of this
+map are fixed time lookup for IRQ numbers, and irq_descs are only
+allocated for in-use IRQs.  The disadvantage is that the table must be
+as large as the largest possible hwirq number.
+
+irq_domain_add_linear() and irq_domain_create_linear() are functionally
+equivalent, except for the first argument is different - the former
+accepts an Open Firmware specific 'struct device_node', while the latter
+accepts a more general abstraction 'struct fwnode_handle'.
+
+The majority of drivers should use the linear map.
+
+Tree
+----
+
+::
+
+	irq_domain_add_tree()
+	irq_domain_create_tree()
+
+The irq_domain maintains a radix tree map from hwirq numbers to Linux
+IRQs.  When an hwirq is mapped, an irq_desc is allocated and the
+hwirq is used as the lookup key for the radix tree.
+
+The tree map is a good choice if the hwirq number can be very large
+since it doesn't need to allocate a table as large as the largest
+hwirq number.  The disadvantage is that hwirq to IRQ number lookup is
+dependent on how many entries are in the table.
+
+irq_domain_add_tree() and irq_domain_create_tree() are functionally
+equivalent, except for the first argument is different - the former
+accepts an Open Firmware specific 'struct device_node', while the latter
+accepts a more general abstraction 'struct fwnode_handle'.
+
+Very few drivers should need this mapping.
+
+No Map
+------
+
+::
+
+	irq_domain_add_nomap()
+
+The No Map mapping is to be used when the hwirq number is
+programmable in the hardware.  In this case it is best to program the
+Linux IRQ number into the hardware itself so that no mapping is
+required.  Calling irq_create_direct_mapping() will allocate a Linux
+IRQ number and call the .map() callback so that driver can program the
+Linux IRQ number into the hardware.
+
+Most drivers cannot use this mapping, and it is now gated on the
+CONFIG_IRQ_DOMAIN_NOMAP option. Please refrain from introducing new
+users of this API.
+
+Legacy
+------
+
+::
+
+	irq_domain_add_simple()
+	irq_domain_add_legacy()
+	irq_domain_create_simple()
+	irq_domain_create_legacy()
+
+The Legacy mapping is a special case for drivers that already have a
+range of irq_descs allocated for the hwirqs.  It is used when the
+driver cannot be immediately converted to use the linear mapping.  For
+example, many embedded system board support files use a set of #defines
+for IRQ numbers that are passed to struct device registrations.  In that
+case the Linux IRQ numbers cannot be dynamically assigned and the legacy
+mapping should be used.
+
+As the name implies, the \*_legacy() functions are deprecated and only
+exist to ease the support of ancient platforms. No new users should be
+added. Same goes for the \*_simple() functions when their use results
+in the legacy behaviour.
+
+The legacy map assumes a contiguous range of IRQ numbers has already
+been allocated for the controller and that the IRQ number can be
+calculated by adding a fixed offset to the hwirq number, and
+visa-versa.  The disadvantage is that it requires the interrupt
+controller to manage IRQ allocations and it requires an irq_desc to be
+allocated for every hwirq, even if it is unused.
+
+The legacy map should only be used if fixed IRQ mappings must be
+supported.  For example, ISA controllers would use the legacy map for
+mapping Linux IRQs 0-15 so that existing ISA drivers get the correct IRQ
+numbers.
+
+Most users of legacy mappings should use irq_domain_add_simple() or
+irq_domain_create_simple() which will use a legacy domain only if an IRQ range
+is supplied by the system and will otherwise use a linear domain mapping.
+The semantics of this call are such that if an IRQ range is specified then
+descriptors will be allocated on-the-fly for it, and if no range is
+specified it will fall through to irq_domain_add_linear() or
+irq_domain_create_linear() which means *no* irq descriptors will be allocated.
+
+A typical use case for simple domains is where an irqchip provider
+is supporting both dynamic and static IRQ assignments.
+
+In order to avoid ending up in a situation where a linear domain is
+used and no descriptor gets allocated it is very important to make sure
+that the driver using the simple domain call irq_create_mapping()
+before any irq_find_mapping() since the latter will actually work
+for the static IRQ assignment case.
+
+irq_domain_add_simple() and irq_domain_create_simple() as well as
+irq_domain_add_legacy() and irq_domain_create_legacy() are functionally
+equivalent, except for the first argument is different - the former
+accepts an Open Firmware specific 'struct device_node', while the latter
+accepts a more general abstraction 'struct fwnode_handle'.
+
+Hierarchy IRQ domain
+--------------------
+
+On some architectures, there may be multiple interrupt controllers
+involved in delivering an interrupt from the device to the target CPU.
+Let's look at a typical interrupt delivering path on x86 platforms::
+
+  Device --> IOAPIC -> Interrupt remapping Controller -> Local APIC -> CPU
+
+There are three interrupt controllers involved:
+
+1) IOAPIC controller
+2) Interrupt remapping controller
+3) Local APIC controller
+
+To support such a hardware topology and make software architecture match
+hardware architecture, an irq_domain data structure is built for each
+interrupt controller and those irq_domains are organized into hierarchy.
+When building irq_domain hierarchy, the irq_domain near to the device is
+child and the irq_domain near to CPU is parent. So a hierarchy structure
+as below will be built for the example above::
+
+	CPU Vector irq_domain (root irq_domain to manage CPU vectors)
+		^
+		|
+	Interrupt Remapping irq_domain (manage irq_remapping entries)
+		^
+		|
+	IOAPIC irq_domain (manage IOAPIC delivery entries/pins)
+
+There are four major interfaces to use hierarchy irq_domain:
+
+1) irq_domain_alloc_irqs(): allocate IRQ descriptors and interrupt
+   controller related resources to deliver these interrupts.
+2) irq_domain_free_irqs(): free IRQ descriptors and interrupt controller
+   related resources associated with these interrupts.
+3) irq_domain_activate_irq(): activate interrupt controller hardware to
+   deliver the interrupt.
+4) irq_domain_deactivate_irq(): deactivate interrupt controller hardware
+   to stop delivering the interrupt.
+
+Following changes are needed to support hierarchy irq_domain:
+
+1) a new field 'parent' is added to struct irq_domain; it's used to
+   maintain irq_domain hierarchy information.
+2) a new field 'parent_data' is added to struct irq_data; it's used to
+   build hierarchy irq_data to match hierarchy irq_domains. The irq_data
+   is used to store irq_domain pointer and hardware irq number.
+3) new callbacks are added to struct irq_domain_ops to support hierarchy
+   irq_domain operations.
+
+With support of hierarchy irq_domain and hierarchy irq_data ready, an
+irq_domain structure is built for each interrupt controller, and an
+irq_data structure is allocated for each irq_domain associated with an
+IRQ. Now we could go one step further to support stacked(hierarchy)
+irq_chip. That is, an irq_chip is associated with each irq_data along
+the hierarchy. A child irq_chip may implement a required action by
+itself or by cooperating with its parent irq_chip.
+
+With stacked irq_chip, interrupt controller driver only needs to deal
+with the hardware managed by itself and may ask for services from its
+parent irq_chip when needed. So we could achieve a much cleaner
+software architecture.
+
+For an interrupt controller driver to support hierarchy irq_domain, it
+needs to:
+
+1) Implement irq_domain_ops.alloc and irq_domain_ops.free
+2) Optionally implement irq_domain_ops.activate and
+   irq_domain_ops.deactivate.
+3) Optionally implement an irq_chip to manage the interrupt controller
+   hardware.
+4) No need to implement irq_domain_ops.map and irq_domain_ops.unmap,
+   they are unused with hierarchy irq_domain.
+
+Hierarchy irq_domain is in no way x86 specific, and is heavily used to
+support other architectures, such as ARM, ARM64 etc.
+
+Debugging
+=========
+
+Most of the internals of the IRQ subsystem are exposed in debugfs by
+turning CONFIG_GENERIC_IRQ_DEBUGFS on.
diff --git a/Documentation/core-api/irq/irqflags-tracing.rst b/Documentation/core-api/irq/irqflags-tracing.rst
new file mode 100644
index 000000000..bdd208259
--- /dev/null
+++ b/Documentation/core-api/irq/irqflags-tracing.rst
@@ -0,0 +1,52 @@
+=======================
+IRQ-flags state tracing
+=======================
+
+:Author: started by Ingo Molnar <mingo@redhat.com>
+
+The "irq-flags tracing" feature "traces" hardirq and softirq state, in
+that it gives interested subsystems an opportunity to be notified of
+every hardirqs-off/hardirqs-on, softirqs-off/softirqs-on event that
+happens in the kernel.
+
+CONFIG_TRACE_IRQFLAGS_SUPPORT is needed for CONFIG_PROVE_SPIN_LOCKING
+and CONFIG_PROVE_RW_LOCKING to be offered by the generic lock debugging
+code. Otherwise only CONFIG_PROVE_MUTEX_LOCKING and
+CONFIG_PROVE_RWSEM_LOCKING will be offered on an architecture - these
+are locking APIs that are not used in IRQ context. (the one exception
+for rwsems is worked around)
+
+Architecture support for this is certainly not in the "trivial"
+category, because lots of lowlevel assembly code deal with irq-flags
+state changes. But an architecture can be irq-flags-tracing enabled in a
+rather straightforward and risk-free manner.
+
+Architectures that want to support this need to do a couple of
+code-organizational changes first:
+
+- add and enable TRACE_IRQFLAGS_SUPPORT in their arch level Kconfig file
+
+and then a couple of functional changes are needed as well to implement
+irq-flags-tracing support:
+
+- in lowlevel entry code add (build-conditional) calls to the
+  trace_hardirqs_off()/trace_hardirqs_on() functions. The lock validator
+  closely guards whether the 'real' irq-flags matches the 'virtual'
+  irq-flags state, and complains loudly (and turns itself off) if the
+  two do not match. Usually most of the time for arch support for
+  irq-flags-tracing is spent in this state: look at the lockdep
+  complaint, try to figure out the assembly code we did not cover yet,
+  fix and repeat. Once the system has booted up and works without a
+  lockdep complaint in the irq-flags-tracing functions arch support is
+  complete.
+- if the architecture has non-maskable interrupts then those need to be
+  excluded from the irq-tracing [and lock validation] mechanism via
+  lockdep_off()/lockdep_on().
+
+In general there is no risk from having an incomplete irq-flags-tracing
+implementation in an architecture: lockdep will detect that and will
+turn itself off. I.e. the lock validator will still be reliable. There
+should be no crashes due to irq-tracing bugs. (except if the assembly
+changes break other code by modifying conditions or registers that
+shouldn't be)
+