arch: Remove Itanium (IA-64) architecture

The Itanium architecture is obsolete, and an informal survey [0] reveals
that any residual use of Itanium hardware in production is mostly HP-UX
or OpenVMS based. The use of Linux on Itanium appears to be limited to
enthusiasts that occasionally boot a fresh Linux kernel to see whether
things are still working as intended, and perhaps to churn out some
distro packages that are rarely used in practice.

None of the original companies behind Itanium still produce or support
any hardware or software for the architecture, and it is listed as
'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers
that contributed on behalf of those companies (nor anyone else, for that
matter) have been willing to support or maintain the architecture
upstream or even be responsible for applying the odd fix. The Intel
firmware team removed all IA-64 support from the Tianocore/EDK2
reference implementation of EFI in 2018. (Itanium is the original
architecture for which EFI was developed, and the way Linux supports it
deviates significantly from other architectures.) Some distros, such as
Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have
dropped support years ago.

While the argument is being made [1] that there is a 'for the common
good' angle to being able to build and run existing projects such as the
Grid Community Toolkit [2] on Itanium for interoperability testing, the
fact remains that none of those projects are known to be deployed on
Linux/ia64, and very few people actually have access to such a system in
the first place. Even if there were ways imaginable in which Linux/ia64
could be put to good use today, what matters is whether anyone is
actually doing that, and this does not appear to be the case.

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.

[0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/
[1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/
[2] https://gridcf.org/gct-docs/latest/index.html
[3] https://cfarm.tetaneutral.net/machines/list/
[4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/
[5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/

Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

1 files changed, 0 insertions, 102 deletions

diff --git a/arch/ia64/lib/checksum.c b/arch/ia64/lib/checksum.c
deleted file mode 100644
index d26517fe3500..000000000000
--- a/arch/ia64/lib/checksum.c
+++ /dev/null
@@ -1,102 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Network checksum routines
- *
- * Copyright (C) 1999, 2003 Hewlett-Packard Co
- *	Stephane Eranian <eranian@hpl.hp.com>
- *
- * Most of the code coming from arch/alpha/lib/checksum.c
- *
- * This file contains network checksum routines that are better done
- * in an architecture-specific manner due to speed..
- */
-
-#include <linux/module.h>
-#include <linux/string.h>
-
-#include <asm/byteorder.h>
-
-static inline unsigned short
-from64to16 (unsigned long x)
-{
-	/* add up 32-bit words for 33 bits */
-	x = (x & 0xffffffff) + (x >> 32);
-	/* add up 16-bit and 17-bit words for 17+c bits */
-	x = (x & 0xffff) + (x >> 16);
-	/* add up 16-bit and 2-bit for 16+c bit */
-	x = (x & 0xffff) + (x >> 16);
-	/* add up carry.. */
-	x = (x & 0xffff) + (x >> 16);
-	return x;
-}
-
-/*
- * computes the checksum of the TCP/UDP pseudo-header
- * returns a 16-bit checksum, already complemented.
- */
-__sum16
-csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
-		  __u8 proto, __wsum sum)
-{
-	return (__force __sum16)~from64to16(
-		(__force u64)saddr + (__force u64)daddr +
-		(__force u64)sum + ((len + proto) << 8));
-}
-
-EXPORT_SYMBOL(csum_tcpudp_magic);
-
-__wsum
-csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
-		   __u8 proto, __wsum sum)
-{
-	unsigned long result;
-
-	result = (__force u64)saddr + (__force u64)daddr +
-		 (__force u64)sum + ((len + proto) << 8);
-
-	/* Fold down to 32-bits so we don't lose in the typedef-less network stack.  */
-	/* 64 to 33 */
-	result = (result & 0xffffffff) + (result >> 32);
-	/* 33 to 32 */
-	result = (result & 0xffffffff) + (result >> 32);
-	return (__force __wsum)result;
-}
-EXPORT_SYMBOL(csum_tcpudp_nofold);
-
-extern unsigned long do_csum (const unsigned char *, long);
-
-/*
- * computes the checksum of a memory block at buff, length len,
- * and adds in "sum" (32-bit)
- *
- * returns a 32-bit number suitable for feeding into itself
- * or csum_tcpudp_magic
- *
- * this function must be called with even lengths, except
- * for the last fragment, which may be odd
- *
- * it's best to have buff aligned on a 32-bit boundary
- */
-__wsum csum_partial(const void *buff, int len, __wsum sum)
-{
-	u64 result = do_csum(buff, len);
-
-	/* add in old sum, and carry.. */
-	result += (__force u32)sum;
-	/* 32+c bits -> 32 bits */
-	result = (result & 0xffffffff) + (result >> 32);
-	return (__force __wsum)result;
-}
-
-EXPORT_SYMBOL(csum_partial);
-
-/*
- * this routine is used for miscellaneous IP-like checksums, mainly
- * in icmp.c
- */
-__sum16 ip_compute_csum (const void *buff, int len)
-{
-	return (__force __sum16)~do_csum(buff,len);
-}
-
-EXPORT_SYMBOL(ip_compute_csum);