Welcome to the developer section of the ARM Linux site. Here, we hope to bring you developer-related information about the ARM Linux kernel, not necessarily limited to the ARM port. All information is freely available, so please browse.

Firstly, a note about Linux kernels, support and the community.

The Linux kernel is always improving over time, as bugs are continually being fixed, not only by the ARM Linux community, but the general Linux community at large. This means that the latest kernel source in a particular kernel series is always the preferred kernel for bug reports to be reported against.

While the community does its best to provide what support it can, there is a limit to what it can do. Regrettably, this means that bug reports for older kernel versions (eg, based upon the 2.x or 3.x series) are too old to offer assistance for; a lot of bugs have been fixed since those kernels were released. As such, bug reports against these kernels will most probably be greeted with a request to update to a later kernel, or may even be ignored.

With the advent of the git tool, there is a lot you can do to help, particularly if the problem is a regression. For example, using git bisect to locate the commit which caused the regression is a good way to help identify the cause of the problem.

If you obtained your kernel from a vendor, please seek support from that vendor. However, please feel free to send bug reports for recent (in terms of mainline kernels) versions to the ARM Linux kernel list in addition to the vendor concerned; it may be that you have discovered a bug which is also present in the main line kernel.

Thanks.

ARM Linux Kernel

• Russell King's Patch Tracking System
• Russell King's ad-hoc Build System
• Machine Registry: values for r1 at boot time for pre Device Tree kernels
• Linux kernel 2.6 and later Bug Tracking System
• Linus' kernel tree
• Linux-next integration testing tree
• rmk's Linux Kernel git tree
• Information about rmk's GIT tree
• rmk's random kernel patches and GIT tree
• Kernel FTP site source verification GPG key (fingerprint: 489E 7F50 8CAB 02B3 57C8 5221 2D9B B8AA 7AE3 402A)
• Stress Testing Tools

ARM Kernel Booting

• 2.4.18-rmk6 and 2.5.17 and later booting requirements
• Setting R2 correctly for booting the kernel (explanation of booting requirements).
• Nico on booting (out of date - 'link' address is no longer relevant to 2.5 and later kernels)
• Wookey on booting
• Makefile symbols
• Kernel boot order
• Advice for head(-armv).S debugging, or why you shouldn't add debugging code to head(-armv).S
• Boot failure checklist
• Booting ARM Linux, Simtec

Documentation

• The C Language Signed/Unsigned Character Type FAQ
• Kernel Compilation
• Tool Chain

Machine Developers

• Notes for ARM Architecture Developers
• Linux memory layout guide

Selected mailings on the Linux-ARM mailing lists

• A note about high bandwidth display resolutions on SA11x0
• The fix for Assabet/Neponset LCD corruption while accessing other resources
• A note describing the problems of Large RAMdisks and why they should not be used.
• How to, and how not to access physical memory
• Sound format conversions and a message from Alan Cox about it.
• Machine related makefile symbols definition.
• ARM endianess explained.
• Where has the -np patch gone?.
• Register tweaking module.
• Setting R2 correctly for booting the kernel.

Miscellaneous

• Dave Gilbert's Linux bits and pieces pages.
• Joe Pranevich's Wonderful world of Linux document describes the changes between Linux 2.2 and Linux 2.4.
• dontdiff file list for Linux kernels.
• Major/Minor device allocation list.
• Diet Libc - a small libc implementation.
• Stanford Checker - automated kernel verification.
• Kernel VM debugging patch: dump out mem_map arrays (this is already included in the latest -rmk patches)
• SA1110 memory timing calculator
• Linus' rant about NOT using volatile for data structures
• A collection of emails from Linus about binary only modules
• Linus on defaulting features to 'y'

Older ARM Linux Kernel

• 2.6 stable series: release notes, patches
• 2.5 development series: release notes, patches
• 2.4 stable series: release notes, patches
• 2.4.0-test series: release notes, patches
• 2.2 stable series: release notes, patches
• Simtec's ARM Kernel Auto-Builder

Older Mainline Kernel

• Linux 2.6 BitKeeper tree (maintained by others)
• Add-on Patches