[PATCH 0/2] binutils-gdb: Remove Itanium (IA-64) architecture

[Tiezhu Yang]

Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

On 05/08/2024 06:05 PM, Frank Scheiner wrote:
> Hi there,
>
> On 08.05.24 11:29, Tiezhu Yang wrote:
>> The Itanium architecture is obsolete, the IA-64 port has been removed
>> from the upstream Linux kernel, this series attempts to remove it in
>> binutils-gdb.git.
>>
>> Please let me know whether it is time to do this work, any comments
>> will be much appreciated.
>
> from our point of view it is not yet time for it as ia64 is neither
> obsolete nor broken. You might not be aware, but we are since a while
> working on getting ia64 back into the Linux kernel and it is
> successfully maintained out of tree since nearly 3 mainline releases
> now. You can read up on our progress on [1] and [2] and after the
> release message for v6.9 on the LKML.
>
> [1]:
> https://lore.kernel.org/all/fe5f6e9b-02a2-42e9-8151-ae4b6fdba7e3@web.de/
>
> [2]:
> https://lore.kernel.org/all/145da253-b3bc-43da-a262-a3ebdfbea5a2@web.de/
>
> The HP Sim platform was also restored in the meantime, so people can
> test ia64 software on e.g. x86_64, up to mainline. See the Linux stable
> release (candidate) builds on [3] for example, all still maintained
> stable kernels work in Ski with HP Sim as platform.
>
> [3]: https://github.com/linux-ia64/linux-stable-rc/actions/runs/8995653713
>
> Each mainline release (candidate) was/is also regularly cross-compiled
> with binutils 2.41/2.42 (since a while) and the latest gcc-14 (now
> gcc-15) snapshot since beginning of the year. The result was/is tested
> on the following real machines:
>
> * rx2620 (w/Montecito)
> * rx4640 (w/Madison)
> * rx2660 (w/Montecito)
> * rx6600 (w/Montvale)
> * rx2800 i2 (w/Tukwila)
>
> ...and of course also in Ski with the HP Sim platform. All that w/o any
> showstopping issues related to binutils or gcc. For the gcc
> cross-compiler LRA was also enabled recently, also w/o any negative
> effect on the resulting kernels.
>
> ****
>
> So is there something broken in binutils for ia64 that we don't know of
> maybe?

Hi all,

Thanks for your replies, maybe it is not time to remove the IA-64 port
in binutils-gdb.git according to the discussions from this mail and
the other mail [1] by GDB maintainer Andrew Burgess, so please ignore
the patches at present unless reaching a consensus.

The initial aim to do this work is based on the following info.

I noticed the following descriptions in the commit message of
kernel patch "arch: Remove Itanium (IA-64) architecture" [2]:

---
There are no emulators widely available, and so boot testing Itanium is
generally infeasible for ordinary contributors. GCC still supports IA-64
but its compile farm [3] no longer has any IA-64 machines. GLIBC would
like to get rid of IA-64 [4] too because it would permit some overdue
code cleanups. In summary, the benefits to the ecosystem of having IA-64
be part of it are mostly theoretical, whereas the maintenance overhead
of keeping it supported is real.

So let's rip off the band aid, and remove the IA-64 arch code entirely.
This follows the timeline proposed by the Debian/ia64 maintainer [5],
which removes support in a controlled manner, leaving IA-64 in a known
good state in the most recent LTS release. Other projects will follow
once the kernel support is removed.
---

and the following descriptions from Debian/ia64 maintainer [3]:

---
I have been thinking about this discussion for a while now and my suggestion
would be to drop ia64 support from the kernel, GRUB and 
gcc/binutils/glibc in
this order:

- Kernel: After the next LTS release
- GRUB: After the 2.12 release
- gcc/binutils/glibc: After support was dropped from the kernel

This way anyone still using ia64 will be able to use it with a supported 
codebase
for an extended time and upstream projects have target releases for 
which they
can plan the removal.

Other projects such as LLVM, OpenJDK and Ruby already support native 
code generation
support for ia64 although OpenJDK still works using the Zero port.
---

[1] https://sourceware.org/pipermail/gdb-patches/2024-May/208949.html
[2] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cf8e8658100d
[3] 
https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/

Thanks,
Tiezhu