Documentation for the Linux kernel source tarball

• Text files in the Documentation directory.
• Output of "make htmldocs".
• man-pages-2.50 (section 2: system calls)

More kernel documentation

• Linux Weekly News kernel articles
• Linux Device Drivers book (third edition) (second edition)
• Ottawa Linux Symposium papers
• IBM Developerworks Linux Library
• Linux Kernel Mailing List FAQ
• Kernel Planet (blog aggregator)

Standards

• Single Unix Specification v6 (See especially system interfaces)
• Linux Foundation's specs page (ELF, Dwarf, ABI...)

todo

• Index of terms used by the kernel