The Linux kernel user-space API guide

While much of the kernel's user-space API is documented elsewhere (particularly in the man-pages project), some user-space information can also be found in the kernel tree itself. This manual is intended to be the place where this information is gathered.

Table of contents

• No New Privileges Flag
• Seccomp BPF (SECure COMPuting with filters)
  • Introduction
  • What it isn't
  • Usage
  • Return values
  • Pitfalls
  • Example
  • Userspace Notification
  • Sysctls
  • Adding architecture support
  • Caveats
• Landlock: unprivileged access control
  • Landlock rules
  • Compatibility
  • Kernel interface
  • Current limitations
  • Previous limitations
  • Kernel support
  • Questions and answers
  • Additional documentation
• unshare system call
  • Change Log
  • Contents
  • 1) Overview
  • 2) Benefits
  • 3) Cost
  • 4) Requirements
  • 5) Functional Specification
  • 6) High Level Design
  • 7) Low Level Design
  • 8) Test Specification
  • 9) Future Work
• Speculation Control
  • PR_GET_SPECULATION_CTRL
  • PR_SET_SPECULATION_CTRL
  • Common error codes
  • PR_SET_SPECULATION_CTRL error codes
  • Speculation misfeature controls
• OpenCAPI (Open Coherent Accelerator Processor Interface)
  • High-level view
  • Device discovery
  • MMIO
  • AFU interrupts
  • char devices
  • Sysfs class
  • User API
• eBPF Userspace API
  • eBPF Syscall
• Linux-specific ELF idiosyncrasies
  • Definitions
  • PT_INTERP
  • PT_GNU_STACK
  • PT_GNU_PROPERTY
• IOCTLs
  • Ioctl Numbers
  • Decoding an IOCTL Magic Number
  • Summary of CDROM ioctl calls
  • Summary of HDIO_ ioctl calls
• IOMMU Userspace API
  • Functionalities
  • Requirements
  • Interfaces
• IOMMUFD
  • Overview
  • Key Concepts
  • IOMMUFD User API
  • IOMMUFD Kernel API
  • Future TODOs
• Linux Media Infrastructure userspace API
  • Introduction
  • Part I - Video for Linux API
  • Part II - Digital TV API
  • Part III - Remote Controller API
  • Part IV - Media Controller API
  • Part V - Consumer Electronics Control API
  • Generic Error Codes
  • Glossary
  • GNU Free Documentation License
  • Video4Linux (V4L) driver-specific documentation
• Netlink Handbook
  • Introduction to Netlink
  • Using Netlink protocol specifications
  • Netlink protocol specifications (in YAML)
  • Netlink spec C code generation
  • Netlink specification support for legacy Generic Netlink families
  • Netlink specification support for raw Netlink families
• Platform Profile Selection (e.g. /sys/firmware/acpi/platform_profile)
• VDUSE - "vDPA Device in Userspace"
  • Create/Destroy VDUSE devices
  • How VDUSE works
• futex2
  • User API