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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
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treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/arm/arm.rst
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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(). ...
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+=======================
+ARM Linux 2.6 and upper
+=======================
+
+ Please check <ftp://ftp.arm.linux.org.uk/pub/armlinux> for
+ updates.
+
+Compilation of kernel
+---------------------
+
+ In order to compile ARM Linux, you will need a compiler capable of
+ generating ARM ELF code with GNU extensions. GCC 3.3 is known to be
+ a good compiler. Fortunately, you needn't guess. The kernel will report
+ an error if your compiler is a recognized offender.
+
+ To build ARM Linux natively, you shouldn't have to alter the ARCH = line
+ in the top level Makefile. However, if you don't have the ARM Linux ELF
+ tools installed as default, then you should change the CROSS_COMPILE
+ line as detailed below.
+
+ If you wish to cross-compile, then alter the following lines in the top
+ level make file::
+
+ ARCH = <whatever>
+
+ with::
+
+ ARCH = arm
+
+ and::
+
+ CROSS_COMPILE=
+
+ to::
+
+ CROSS_COMPILE=<your-path-to-your-compiler-without-gcc>
+
+ eg.::
+
+ CROSS_COMPILE=arm-linux-
+
+ Do a 'make config', followed by 'make Image' to build the kernel
+ (arch/arm/boot/Image). A compressed image can be built by doing a
+ 'make zImage' instead of 'make Image'.
+
+
+Bug reports etc
+---------------
+
+ Please send patches to the patch system. For more information, see
+ http://www.arm.linux.org.uk/developer/patches/info.php Always include some
+ explanation as to what the patch does and why it is needed.
+
+ Bug reports should be sent to linux-arm-kernel@lists.arm.linux.org.uk,
+ or submitted through the web form at
+ http://www.arm.linux.org.uk/developer/
+
+ When sending bug reports, please ensure that they contain all relevant
+ information, eg. the kernel messages that were printed before/during
+ the problem, what you were doing, etc.
+
+
+Include files
+-------------
+
+ Several new include directories have been created under include/asm-arm,
+ which are there to reduce the clutter in the top-level directory. These
+ directories, and their purpose is listed below:
+
+ ============= ==========================================================
+ `arch-*` machine/platform specific header files
+ `hardware` driver-internal ARM specific data structures/definitions
+ `mach` descriptions of generic ARM to specific machine interfaces
+ `proc-*` processor dependent header files (currently only two
+ categories)
+ ============= ==========================================================
+
+
+Machine/Platform support
+------------------------
+
+ The ARM tree contains support for a lot of different machine types. To
+ continue supporting these differences, it has become necessary to split
+ machine-specific parts by directory. For this, the machine category is
+ used to select which directories and files get included (we will use
+ $(MACHINE) to refer to the category)
+
+ To this end, we now have arch/arm/mach-$(MACHINE) directories which are
+ designed to house the non-driver files for a particular machine (eg, PCI,
+ memory management, architecture definitions etc). For all future
+ machines, there should be a corresponding arch/arm/mach-$(MACHINE)/include/mach
+ directory.
+
+
+Modules
+-------
+
+ Although modularisation is supported (and required for the FP emulator),
+ each module on an ARM2/ARM250/ARM3 machine when is loaded will take
+ memory up to the next 32k boundary due to the size of the pages.
+ Therefore, is modularisation on these machines really worth it?
+
+ However, ARM6 and up machines allow modules to take multiples of 4k, and
+ as such Acorn RiscPCs and other architectures using these processors can
+ make good use of modularisation.
+
+
+ADFS Image files
+----------------
+
+ You can access image files on your ADFS partitions by mounting the ADFS
+ partition, and then using the loopback device driver. You must have
+ losetup installed.
+
+ Please note that the PCEmulator DOS partitions have a partition table at
+ the start, and as such, you will have to give '-o offset' to losetup.
+
+
+Request to developers
+---------------------
+
+ When writing device drivers which include a separate assembler file, please
+ include it in with the C file, and not the arch/arm/lib directory. This
+ allows the driver to be compiled as a loadable module without requiring
+ half the code to be compiled into the kernel image.
+
+ In general, try to avoid using assembler unless it is really necessary. It
+ makes drivers far less easy to port to other hardware.
+
+
+ST506 hard drives
+-----------------
+
+ The ST506 hard drive controllers seem to be working fine (if a little
+ slowly). At the moment they will only work off the controllers on an
+ A4x0's motherboard, but for it to work off a Podule just requires
+ someone with a podule to add the addresses for the IRQ mask and the
+ HDC base to the source.
+
+ As of 31/3/96 it works with two drives (you should get the ADFS
+ `*configure` harddrive set to 2). I've got an internal 20MB and a great
+ big external 5.25" FH 64MB drive (who could ever want more :-) ).
+
+ I've just got 240K/s off it (a dd with bs=128k); thats about half of what
+ RiscOS gets; but it's a heck of a lot better than the 50K/s I was getting
+ last week :-)
+
+ Known bug: Drive data errors can cause a hang; including cases where
+ the controller has fixed the error using ECC. (Possibly ONLY
+ in that case...hmm).
+
+
+1772 Floppy
+-----------
+ This also seems to work OK, but hasn't been stressed much lately. It
+ hasn't got any code for disc change detection in there at the moment which
+ could be a bit of a problem! Suggestions on the correct way to do this
+ are welcome.
+
+
+`CONFIG_MACH_` and `CONFIG_ARCH_`
+---------------------------------
+ A change was made in 2003 to the macro names for new machines.
+ Historically, `CONFIG_ARCH_` was used for the bonafide architecture,
+ e.g. SA1100, as well as implementations of the architecture,
+ e.g. Assabet. It was decided to change the implementation macros
+ to read `CONFIG_MACH_` for clarity. Moreover, a retroactive fixup has
+ not been made because it would complicate patching.
+
+ Previous registrations may be found online.
+
+ <http://www.arm.linux.org.uk/developer/machines/>
+
+Kernel entry (head.S)
+---------------------
+ The initial entry into the kernel is via head.S, which uses machine
+ independent code. The machine is selected by the value of 'r1' on
+ entry, which must be kept unique.
+
+ Due to the large number of machines which the ARM port of Linux provides
+ for, we have a method to manage this which ensures that we don't end up
+ duplicating large amounts of code.
+
+ We group machine (or platform) support code into machine classes. A
+ class typically based around one or more system on a chip devices, and
+ acts as a natural container around the actual implementations. These
+ classes are given directories - arch/arm/mach-<class> - which contain
+ the source files and include/mach/ to support the machine class.
+
+ For example, the SA1100 class is based upon the SA1100 and SA1110 SoC
+ devices, and contains the code to support the way the on-board and off-
+ board devices are used, or the device is setup, and provides that
+ machine specific "personality."
+
+ For platforms that support device tree (DT), the machine selection is
+ controlled at runtime by passing the device tree blob to the kernel. At
+ compile-time, support for the machine type must be selected. This allows for
+ a single multiplatform kernel build to be used for several machine types.
+
+ For platforms that do not use device tree, this machine selection is
+ controlled by the machine type ID, which acts both as a run-time and a
+ compile-time code selection method. You can register a new machine via the
+ web site at:
+
+ <http://www.arm.linux.org.uk/developer/machines/>
+
+ Note: Please do not register a machine type for DT-only platforms. If your
+ platform is DT-only, you do not need a registered machine type.
+
+---
+
+Russell King (15/03/2004)