From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- Documentation/ia64/aliasing.rst | 246 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 246 insertions(+) create mode 100644 Documentation/ia64/aliasing.rst (limited to 'Documentation/ia64/aliasing.rst') diff --git a/Documentation/ia64/aliasing.rst b/Documentation/ia64/aliasing.rst new file mode 100644 index 000000000..36a1e1d48 --- /dev/null +++ b/Documentation/ia64/aliasing.rst @@ -0,0 +1,246 @@ +================================== +Memory Attribute Aliasing on IA-64 +================================== + +Bjorn Helgaas + +May 4, 2006 + + +Memory Attributes +================= + + Itanium supports several attributes for virtual memory references. + The attribute is part of the virtual translation, i.e., it is + contained in the TLB entry. The ones of most interest to the Linux + kernel are: + + == ====================== + WB Write-back (cacheable) + UC Uncacheable + WC Write-coalescing + == ====================== + + System memory typically uses the WB attribute. The UC attribute is + used for memory-mapped I/O devices. The WC attribute is uncacheable + like UC is, but writes may be delayed and combined to increase + performance for things like frame buffers. + + The Itanium architecture requires that we avoid accessing the same + page with both a cacheable mapping and an uncacheable mapping[1]. + + The design of the chipset determines which attributes are supported + on which regions of the address space. For example, some chipsets + support either WB or UC access to main memory, while others support + only WB access. + +Memory Map +========== + + Platform firmware describes the physical memory map and the + supported attributes for each region. At boot-time, the kernel uses + the EFI GetMemoryMap() interface. ACPI can also describe memory + devices and the attributes they support, but Linux/ia64 currently + doesn't use this information. + + The kernel uses the efi_memmap table returned from GetMemoryMap() to + learn the attributes supported by each region of physical address + space. Unfortunately, this table does not completely describe the + address space because some machines omit some or all of the MMIO + regions from the map. + + The kernel maintains another table, kern_memmap, which describes the + memory Linux is actually using and the attribute for each region. + This contains only system memory; it does not contain MMIO space. + + The kern_memmap table typically contains only a subset of the system + memory described by the efi_memmap. Linux/ia64 can't use all memory + in the system because of constraints imposed by the identity mapping + scheme. + + The efi_memmap table is preserved unmodified because the original + boot-time information is required for kexec. + +Kernel Identity Mappings +======================== + + Linux/ia64 identity mappings are done with large pages, currently + either 16MB or 64MB, referred to as "granules." Cacheable mappings + are speculative[2], so the processor can read any location in the + page at any time, independent of the programmer's intentions. This + means that to avoid attribute aliasing, Linux can create a cacheable + identity mapping only when the entire granule supports cacheable + access. + + Therefore, kern_memmap contains only full granule-sized regions that + can referenced safely by an identity mapping. + + Uncacheable mappings are not speculative, so the processor will + generate UC accesses only to locations explicitly referenced by + software. This allows UC identity mappings to cover granules that + are only partially populated, or populated with a combination of UC + and WB regions. + +User Mappings +============= + + User mappings are typically done with 16K or 64K pages. The smaller + page size allows more flexibility because only 16K or 64K has to be + homogeneous with respect to memory attributes. + +Potential Attribute Aliasing Cases +================================== + + There are several ways the kernel creates new mappings: + +mmap of /dev/mem +---------------- + + This uses remap_pfn_range(), which creates user mappings. These + mappings may be either WB or UC. If the region being mapped + happens to be in kern_memmap, meaning that it may also be mapped + by a kernel identity mapping, the user mapping must use the same + attribute as the kernel mapping. + + If the region is not in kern_memmap, the user mapping should use + an attribute reported as being supported in the EFI memory map. + + Since the EFI memory map does not describe MMIO on some + machines, this should use an uncacheable mapping as a fallback. + +mmap of /sys/class/pci_bus/.../legacy_mem +----------------------------------------- + + This is very similar to mmap of /dev/mem, except that legacy_mem + only allows mmap of the one megabyte "legacy MMIO" area for a + specific PCI bus. Typically this is the first megabyte of + physical address space, but it may be different on machines with + several VGA devices. + + "X" uses this to access VGA frame buffers. Using legacy_mem + rather than /dev/mem allows multiple instances of X to talk to + different VGA cards. + + The /dev/mem mmap constraints apply. + +mmap of /proc/bus/pci/.../??.? +------------------------------ + + This is an MMIO mmap of PCI functions, which additionally may or + may not be requested as using the WC attribute. + + If WC is requested, and the region in kern_memmap is either WC + or UC, and the EFI memory map designates the region as WC, then + the WC mapping is allowed. + + Otherwise, the user mapping must use the same attribute as the + kernel mapping. + +read/write of /dev/mem +---------------------- + + This uses copy_from_user(), which implicitly uses a kernel + identity mapping. This is obviously safe for things in + kern_memmap. + + There may be corner cases of things that are not in kern_memmap, + but could be accessed this way. For example, registers in MMIO + space are not in kern_memmap, but could be accessed with a UC + mapping. This would not cause attribute aliasing. But + registers typically can be accessed only with four-byte or + eight-byte accesses, and the copy_from_user() path doesn't allow + any control over the access size, so this would be dangerous. + +ioremap() +--------- + + This returns a mapping for use inside the kernel. + + If the region is in kern_memmap, we should use the attribute + specified there. + + If the EFI memory map reports that the entire granule supports + WB, we should use that (granules that are partially reserved + or occupied by firmware do not appear in kern_memmap). + + If the granule contains non-WB memory, but we can cover the + region safely with kernel page table mappings, we can use + ioremap_page_range() as most other architectures do. + + Failing all of the above, we have to fall back to a UC mapping. + +Past Problem Cases +================== + +mmap of various MMIO regions from /dev/mem by "X" on Intel platforms +-------------------------------------------------------------------- + + The EFI memory map may not report these MMIO regions. + + These must be allowed so that X will work. This means that + when the EFI memory map is incomplete, every /dev/mem mmap must + succeed. It may create either WB or UC user mappings, depending + on whether the region is in kern_memmap or the EFI memory map. + +mmap of 0x0-0x9FFFF /dev/mem by "hwinfo" on HP sx1000 with VGA enabled +---------------------------------------------------------------------- + + The EFI memory map reports the following attributes: + + =============== ======= ================== + 0x00000-0x9FFFF WB only + 0xA0000-0xBFFFF UC only (VGA frame buffer) + 0xC0000-0xFFFFF WB only + =============== ======= ================== + + This mmap is done with user pages, not kernel identity mappings, + so it is safe to use WB mappings. + + The kernel VGA driver may ioremap the VGA frame buffer at 0xA0000, + which uses a granule-sized UC mapping. This granule will cover some + WB-only memory, but since UC is non-speculative, the processor will + never generate an uncacheable reference to the WB-only areas unless + the driver explicitly touches them. + +mmap of 0x0-0xFFFFF legacy_mem by "X" +------------------------------------- + + If the EFI memory map reports that the entire range supports the + same attributes, we can allow the mmap (and we will prefer WB if + supported, as is the case with HP sx[12]000 machines with VGA + disabled). + + If EFI reports the range as partly WB and partly UC (as on sx[12]000 + machines with VGA enabled), we must fail the mmap because there's no + safe attribute to use. + + If EFI reports some of the range but not all (as on Intel firmware + that doesn't report the VGA frame buffer at all), we should fail the + mmap and force the user to map just the specific region of interest. + +mmap of 0xA0000-0xBFFFF legacy_mem by "X" on HP sx1000 with VGA disabled +------------------------------------------------------------------------ + + The EFI memory map reports the following attributes:: + + 0x00000-0xFFFFF WB only (no VGA MMIO hole) + + This is a special case of the previous case, and the mmap should + fail for the same reason as above. + +read of /sys/devices/.../rom +---------------------------- + + For VGA devices, this may cause an ioremap() of 0xC0000. This + used to be done with a UC mapping, because the VGA frame buffer + at 0xA0000 prevents use of a WB granule. The UC mapping causes + an MCA on HP sx[12]000 chipsets. + + We should use WB page table mappings to avoid covering the VGA + frame buffer. + +Notes +===== + + [1] SDM rev 2.2, vol 2, sec 4.4.1. + [2] SDM rev 2.2, vol 2, sec 4.4.6. -- cgit v1.2.3