Linux Kernel Orphans Itanium Support, Linus Torvalds Acknowledges Its Death

Just last week I wrote about Itanium IA-64 support in Linux kernel being broken for a month during the Linux 5.11 kernel cycle. That was fixed but since then another regression came to light that had been affecting all IA-64 hardware since a patch was merged back in October. A fix for that latest regression has landed while in the process now marking the Itanium architecture as orphaned.

Last year when converting the Itanium architecture code to use the legacy timer tick, that ended up regressing the architecture support. That regression broke the IA-64 code and led to RCU stall errors and a fast system clock. The precise cause of that regression wasn't figured out due to lack of hardware access but the patch at least fixes the support.

Sent in today as part of asm-generic-fixes is that fix to the Itanium code. With Intel engineers not even maintaining their IA64 kernel tree or working on any measurable improvements for that architecture code, in the process today the Itanium IA-64 code in the Linux kernel has been marked as "orphaned".

As part of the orphaning, Linus Torvalds went on to add with today's commit:

HPE no longer accepts orders for new Itanium hardware, and Intel stopped accepting orders a year ago. While Intel is still officially shipping chips until July 29, 2021, it's unlikely that any such orders actually exist.

It's dead, Jim.

Itanium had a two decade run while the Itanium 9700 "Kittson" processors were the last of the series that launched back in 2017. In 2019 was when Intel EOL'ed Itanium with the last processors to be shipped by the end of this year, should there be any remaining orders on the books. HPE stopped their Itanium server orders back on 31 December.

For the Itanium servers out there today, it's unlikely they are actively being updated to new Linux kernel releases in any meaningful way and likely in the not too distant future this Itanium support might very well be removed -- orphaning the code is a step toward its eventual removal. Even the Linux distribution support for Itanium has been scarce with Red Hat not supporting it since RHEL5, SUSE stopped supporting it after SUSE Linux 11, and most other Linux distributions having stopped providing new releases for IA-64 and for many no longer even within their enterprise software support periods.

With Intel and HPE no longer actively working on the IA-64 Linux support, it's basically up to any remaining organizations still relying on IA-64 or hobbyists to take over if they don't want to see the kernel support eventually removed. While Linux is known for its diverse hardware support, from time to time it does drop support for old architectures or hardware platforms that fall into disrepair. At the same time it does welcome support for old hardware -- most recently, Nintendo 64 support slated for Linux 5.12 -- as long as it ends up being maintained. So we'll see what happens with this now-orphaned Itanium Linux code moving ahead.