Linux kernel source tree
 
 
 
 
 
 
Go to file
Linus Torvalds c43267e679 arm64 updates for 7.1:
Core features:
 
  - Add support for FEAT_LSUI, allowing futex atomic operations without
    toggling Privileged Access Never (PAN)
 
  - Further refactor the arm64 exception handling code towards the
    generic entry infrastructure
 
  - Optimise __READ_ONCE() with CONFIG_LTO=y and allow alias analysis
    through it
 
 Memory management:
 
  - Refactor the arm64 TLB invalidation API and implementation for better
    control over barrier placement and level-hinted invalidation
 
  - Enable batched TLB flushes during memory hot-unplug
 
  - Fix rodata=full block mapping support for realm guests (when
    BBML2_NOABORT is available)
 
 Perf and PMU:
 
  - Add support for a whole bunch of system PMUs featured in NVIDIA's
    Tegra410 SoC (cspmu extensions for the fabric and PCIe, new drivers
    for CPU/C2C memory latency PMUs)
 
  - Clean up iomem resource handling in the Arm CMN driver
 
  - Fix signedness handling of AA64DFR0.{PMUVer,PerfMon}
 
 MPAM (Memory Partitioning And Monitoring):
 
  - Add architecture context-switch and hiding of the feature from KVM
 
  - Add interface to allow MPAM to be exposed to user-space using resctrl
 
  - Add errata workaround for some existing platforms
 
  - Add documentation for using MPAM and what shape of platforms can use
    resctrl
 
 Miscellaneous:
 
  - Check DAIF (and PMR, where relevant) at task-switch time
 
  - Skip TFSR_EL1 checks and barriers in synchronous MTE tag check mode
    (only relevant to asynchronous or asymmetric tag check modes)
 
  - Remove a duplicate allocation in the kexec code
 
  - Remove redundant save/restore of SCS SP on entry to/from EL0
 
  - Generate the KERNEL_HWCAP_ definitions from the arm64 hwcap
    descriptions
 
  - Add kselftest coverage for cmpbr_sigill()
 
  - Update sysreg definitions
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEE5RElWfyWxS+3PLO2a9axLQDIXvEFAmnc8DEACgkQa9axLQDI
 XvFauRAAhc1cIgoRpgtdZd7+3/g457teDPYA3L/CjJzI28aesIpV/ECrEw2GL4xs
 HrQfijF4oyCDbBwh0sAascO/H7RoyOranlbuc+fVJ6Bj6gP9STzR4GmscsWkAMSJ
 vA3Jd1DREdDBO2sjw+hGhht84nRlcfY1FyORJP+1JaFH4oWTWsRNeOZIiI3BhxR8
 EtFP9E8r2Esxi/FmZb/47m7kYCEH+XsrzQvBQNLVCH899QX2Hn0kAY70ndq2ZiQl
 n+zLAe7FBFwKzUVmlgWuhjrWMmK+1TthK/XQuOtxg13dHmX+vE/j+A+dOqRWSfHY
 ktNcWaf6m4+TWKVeVTe4E1cnSuwTQTm4VQKd9zaeQxiZYyYJhCQjXuEZg3vDmDbq
 F6D3MpTaJHRRWp0rEurxnSBlmQPCBE2IxEBdSrjd/WJ6T9e1oYwWiSJSS7bGCgGr
 dd/XLsOY7Um5n4ooIFEZc1de6VO6/VTKjmxnBMgU+Sa1REbLpD438IX/6CjzG5qM
 l5Ulke/c6/a/faeVCEpZpD8JuvNOzo9RISDPrNg1KKAL+OSU+9tgmVjIFPhDDB0w
 zNTqT7YJIhxlJxnUGWDk8YNsTjT3OzyquY9UT1tBTBqC0k13J2i2ev30toUez7xj
 2aV+9qMpunbLtwYhXNun1hBFiYrCxpX7I8ha0hXiXL0CywVOPTI=
 =CnVn
 -----END PGP SIGNATURE-----

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "The biggest changes are MPAM enablement in drivers/resctrl and new PMU
  support under drivers/perf.

  On the core side, FEAT_LSUI lets futex atomic operations with EL0
  permissions, avoiding PAN toggling.

  The rest is mostly TLB invalidation refactoring, further generic entry
  work, sysreg updates and a few fixes.

  Core features:

   - Add support for FEAT_LSUI, allowing futex atomic operations without
     toggling Privileged Access Never (PAN)

   - Further refactor the arm64 exception handling code towards the
     generic entry infrastructure

   - Optimise __READ_ONCE() with CONFIG_LTO=y and allow alias analysis
     through it

  Memory management:

   - Refactor the arm64 TLB invalidation API and implementation for
     better control over barrier placement and level-hinted invalidation

   - Enable batched TLB flushes during memory hot-unplug

   - Fix rodata=full block mapping support for realm guests (when
     BBML2_NOABORT is available)

  Perf and PMU:

   - Add support for a whole bunch of system PMUs featured in NVIDIA's
     Tegra410 SoC (cspmu extensions for the fabric and PCIe, new drivers
     for CPU/C2C memory latency PMUs)

   - Clean up iomem resource handling in the Arm CMN driver

   - Fix signedness handling of AA64DFR0.{PMUVer,PerfMon}

  MPAM (Memory Partitioning And Monitoring):

   - Add architecture context-switch and hiding of the feature from KVM

   - Add interface to allow MPAM to be exposed to user-space using
     resctrl

   - Add errata workaround for some existing platforms

   - Add documentation for using MPAM and what shape of platforms can
     use resctrl

  Miscellaneous:

   - Check DAIF (and PMR, where relevant) at task-switch time

   - Skip TFSR_EL1 checks and barriers in synchronous MTE tag check mode
     (only relevant to asynchronous or asymmetric tag check modes)

   - Remove a duplicate allocation in the kexec code

   - Remove redundant save/restore of SCS SP on entry to/from EL0

   - Generate the KERNEL_HWCAP_ definitions from the arm64 hwcap
     descriptions

   - Add kselftest coverage for cmpbr_sigill()

   - Update sysreg definitions"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (109 commits)
  arm64: rsi: use linear-map alias for realm config buffer
  arm64: Kconfig: fix duplicate word in CMDLINE help text
  arm64: mte: Skip TFSR_EL1 checks and barriers in synchronous tag check mode
  arm64/sysreg: Update ID_AA64SMFR0_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64ZFR0_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64FPFR0_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64ISAR2_EL1 description to DDI0601 2025-12
  arm64/sysreg: Update ID_AA64ISAR0_EL1 description to DDI0601 2025-12
  arm64/hwcap: Generate the KERNEL_HWCAP_ definitions for the hwcaps
  arm64: kexec: Remove duplicate allocation for trans_pgd
  ACPI: AGDI: fix missing newline in error message
  arm64: Check DAIF (and PMR) at task-switch time
  arm64: entry: Use split preemption logic
  arm64: entry: Use irqentry_{enter_from,exit_to}_kernel_mode()
  arm64: entry: Consistently prefix arm64-specific wrappers
  arm64: entry: Don't preempt with SError or Debug masked
  entry: Split preemption from irqentry_exit_to_kernel_mode()
  entry: Split kernel mode logic from irqentry_{enter,exit}()
  entry: Move irqentry_enter() prototype later
  entry: Remove local_irq_{enable,disable}_exit_to_user()
  ...
2026-04-14 16:48:56 -07:00
Documentation arm64 updates for 7.1: 2026-04-14 16:48:56 -07:00
LICENSES LICENSES: Add modern form of the LGPL-2.1 tags to the usage guide section 2025-10-22 07:58:19 +02:00
arch arm64 updates for 7.1: 2026-04-14 16:48:56 -07:00
block for-7.1/block-20260411 2026-04-13 15:51:31 -07:00
certs Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
crypto CRC updates for 7.1 2026-04-13 17:36:04 -07:00
drivers arm64 updates for 7.1: 2026-04-14 16:48:56 -07:00
fs — Add return value descriptions to several internal functions, addressing 2026-04-14 14:46:37 -07:00
include arm64 updates for 7.1: 2026-04-14 16:48:56 -07:00
init Scheduler changes for v7.1: 2026-04-14 13:33:36 -07:00
io_uring for-7.1/io_uring-20260411 2026-04-13 16:22:30 -07:00
ipc Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kernel arm64 updates for 7.1: 2026-04-14 16:48:56 -07:00
lib Locking updates for v7.1: 2026-04-14 12:36:25 -07:00
mm for-7.1/block-20260411 2026-04-13 15:51:31 -07:00
net Crypto library updates for 7.1 2026-04-13 17:31:39 -07:00
rust Locking updates for v7.1: 2026-04-14 12:36:25 -07:00
samples Driver core changes for 7.1-rc1 2026-04-13 19:03:11 -07:00
scripts objtool updates for v7.1: 2026-04-14 13:00:04 -07:00
security Crypto library updates for 7.1 2026-04-13 17:31:39 -07:00
sound - Complete LASS enabling: deal with vsyscall and EFI 2026-04-14 14:24:45 -07:00
tools arm64 updates for 7.1: 2026-04-14 16:48:56 -07:00
usr kbuild: uapi: also test UAPI headers against C++ compilers 2026-03-25 13:24:42 +01:00
virt vfs-7.1-rc1.bh.metadata 2026-04-13 12:46:42 -07:00
.clang-format Devicetree updates for v7.0: 2026-02-11 18:27:08 -08:00
.clippy.toml rust: bump Clippy's MSRV and clean `incompatible_msrv` allows 2026-04-07 09:51:39 +02:00
.cocciconfig
.editorconfig editorconfig: add rst extension 2026-01-26 19:07:09 -08:00
.get_maintainer.ignore .get_maintainer.ignore: add myself 2026-04-02 16:48:25 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rust: provide an option to inline C helpers into Rust 2026-03-30 02:03:52 +02:00
.mailmap MAINTAINERS, mailmap: Change Ulf Hansson's email 2026-04-07 14:17:48 +02:00
.pylintrc docs: Move the python libraries to tools/lib/python 2025-11-18 09:22:40 -07:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: remove Thomas Falcon from IBM ibmvnic 2026-03-05 07:35:45 -08:00
Kbuild checksyscalls: move instance functionality into generic code 2026-04-05 09:21:32 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS — Reference the tip tree maintainer handbook directly from the relevant 2026-04-14 15:15:08 -07:00
Makefile Kbuild/Kconfig updates for 7.1 2026-04-14 09:18:40 -07:00
README docs: add AI Coding Assistants documentation 2026-01-06 14:55:06 -07:00

README

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst