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The Itanium architecture is obsolete, and an informal survey [0] reveals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, 216 deletions

diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h
deleted file mode 100644
index 6540a628d257..000000000000
--- a/arch/ia64/include/asm/atomic.h
+++ /dev/null
@@ -1,216 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_IA64_ATOMIC_H
-#define _ASM_IA64_ATOMIC_H
-
-/*
- * Atomic operations that C can't guarantee us.  Useful for
- * resource counting etc..
- *
- * NOTE: don't mess with the types below!  The "unsigned long" and
- * "int" types were carefully placed so as to ensure proper operation
- * of the macros.
- *
- * Copyright (C) 1998, 1999, 2002-2003 Hewlett-Packard Co
- *	David Mosberger-Tang <davidm@hpl.hp.com>
- */
-#include <linux/types.h>
-
-#include <asm/intrinsics.h>
-#include <asm/barrier.h>
-
-
-#define ATOMIC64_INIT(i)	{ (i) }
-
-#define arch_atomic_read(v)	READ_ONCE((v)->counter)
-#define arch_atomic64_read(v)	READ_ONCE((v)->counter)
-
-#define arch_atomic_set(v,i)	WRITE_ONCE(((v)->counter), (i))
-#define arch_atomic64_set(v,i)	WRITE_ONCE(((v)->counter), (i))
-
-#define ATOMIC_OP(op, c_op)						\
-static __inline__ int							\
-ia64_atomic_##op (int i, atomic_t *v)					\
-{									\
-	__s32 old, new;							\
-	CMPXCHG_BUGCHECK_DECL						\
-									\
-	do {								\
-		CMPXCHG_BUGCHECK(v);					\
-		old = arch_atomic_read(v);				\
-		new = old c_op i;					\
-	} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic_t)) != old); \
-	return new;							\
-}
-
-#define ATOMIC_FETCH_OP(op, c_op)					\
-static __inline__ int							\
-ia64_atomic_fetch_##op (int i, atomic_t *v)				\
-{									\
-	__s32 old, new;							\
-	CMPXCHG_BUGCHECK_DECL						\
-									\
-	do {								\
-		CMPXCHG_BUGCHECK(v);					\
-		old = arch_atomic_read(v);				\
-		new = old c_op i;					\
-	} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic_t)) != old); \
-	return old;							\
-}
-
-#define ATOMIC_OPS(op, c_op)						\
-	ATOMIC_OP(op, c_op)						\
-	ATOMIC_FETCH_OP(op, c_op)
-
-ATOMIC_OPS(add, +)
-ATOMIC_OPS(sub, -)
-
-#ifdef __OPTIMIZE__
-#define __ia64_atomic_const(i)						\
-	static const int __ia64_atomic_p = __builtin_constant_p(i) ?	\
-		((i) == 1 || (i) == 4 || (i) == 8 || (i) == 16 ||	\
-		 (i) == -1 || (i) == -4 || (i) == -8 || (i) == -16) : 0;\
-	__ia64_atomic_p
-#else
-#define __ia64_atomic_const(i)	0
-#endif
-
-#define arch_atomic_add_return(i,v)					\
-({									\
-	int __ia64_aar_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetch_and_add(__ia64_aar_i, &(v)->counter)	\
-		: ia64_atomic_add(__ia64_aar_i, v);			\
-})
-
-#define arch_atomic_sub_return(i,v)					\
-({									\
-	int __ia64_asr_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetch_and_add(-__ia64_asr_i, &(v)->counter)	\
-		: ia64_atomic_sub(__ia64_asr_i, v);			\
-})
-
-#define arch_atomic_fetch_add(i,v)					\
-({									\
-	int __ia64_aar_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetchadd(__ia64_aar_i, &(v)->counter, acq)	\
-		: ia64_atomic_fetch_add(__ia64_aar_i, v);		\
-})
-
-#define arch_atomic_fetch_sub(i,v)					\
-({									\
-	int __ia64_asr_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetchadd(-__ia64_asr_i, &(v)->counter, acq)	\
-		: ia64_atomic_fetch_sub(__ia64_asr_i, v);		\
-})
-
-ATOMIC_FETCH_OP(and, &)
-ATOMIC_FETCH_OP(or, |)
-ATOMIC_FETCH_OP(xor, ^)
-
-#define arch_atomic_and(i,v)	(void)ia64_atomic_fetch_and(i,v)
-#define arch_atomic_or(i,v)	(void)ia64_atomic_fetch_or(i,v)
-#define arch_atomic_xor(i,v)	(void)ia64_atomic_fetch_xor(i,v)
-
-#define arch_atomic_fetch_and(i,v)	ia64_atomic_fetch_and(i,v)
-#define arch_atomic_fetch_or(i,v)	ia64_atomic_fetch_or(i,v)
-#define arch_atomic_fetch_xor(i,v)	ia64_atomic_fetch_xor(i,v)
-
-#undef ATOMIC_OPS
-#undef ATOMIC_FETCH_OP
-#undef ATOMIC_OP
-
-#define ATOMIC64_OP(op, c_op)						\
-static __inline__ s64							\
-ia64_atomic64_##op (s64 i, atomic64_t *v)				\
-{									\
-	s64 old, new;							\
-	CMPXCHG_BUGCHECK_DECL						\
-									\
-	do {								\
-		CMPXCHG_BUGCHECK(v);					\
-		old = arch_atomic64_read(v);				\
-		new = old c_op i;					\
-	} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic64_t)) != old); \
-	return new;							\
-}
-
-#define ATOMIC64_FETCH_OP(op, c_op)					\
-static __inline__ s64							\
-ia64_atomic64_fetch_##op (s64 i, atomic64_t *v)				\
-{									\
-	s64 old, new;							\
-	CMPXCHG_BUGCHECK_DECL						\
-									\
-	do {								\
-		CMPXCHG_BUGCHECK(v);					\
-		old = arch_atomic64_read(v);				\
-		new = old c_op i;					\
-	} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic64_t)) != old); \
-	return old;							\
-}
-
-#define ATOMIC64_OPS(op, c_op)						\
-	ATOMIC64_OP(op, c_op)						\
-	ATOMIC64_FETCH_OP(op, c_op)
-
-ATOMIC64_OPS(add, +)
-ATOMIC64_OPS(sub, -)
-
-#define arch_atomic64_add_return(i,v)					\
-({									\
-	s64 __ia64_aar_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetch_and_add(__ia64_aar_i, &(v)->counter)	\
-		: ia64_atomic64_add(__ia64_aar_i, v);			\
-})
-
-#define arch_atomic64_sub_return(i,v)					\
-({									\
-	s64 __ia64_asr_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetch_and_add(-__ia64_asr_i, &(v)->counter)	\
-		: ia64_atomic64_sub(__ia64_asr_i, v);			\
-})
-
-#define arch_atomic64_fetch_add(i,v)					\
-({									\
-	s64 __ia64_aar_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetchadd(__ia64_aar_i, &(v)->counter, acq)	\
-		: ia64_atomic64_fetch_add(__ia64_aar_i, v);		\
-})
-
-#define arch_atomic64_fetch_sub(i,v)					\
-({									\
-	s64 __ia64_asr_i = (i);						\
-	__ia64_atomic_const(i)						\
-		? ia64_fetchadd(-__ia64_asr_i, &(v)->counter, acq)	\
-		: ia64_atomic64_fetch_sub(__ia64_asr_i, v);		\
-})
-
-ATOMIC64_FETCH_OP(and, &)
-ATOMIC64_FETCH_OP(or, |)
-ATOMIC64_FETCH_OP(xor, ^)
-
-#define arch_atomic64_and(i,v)	(void)ia64_atomic64_fetch_and(i,v)
-#define arch_atomic64_or(i,v)	(void)ia64_atomic64_fetch_or(i,v)
-#define arch_atomic64_xor(i,v)	(void)ia64_atomic64_fetch_xor(i,v)
-
-#define arch_atomic64_fetch_and(i,v)	ia64_atomic64_fetch_and(i,v)
-#define arch_atomic64_fetch_or(i,v)	ia64_atomic64_fetch_or(i,v)
-#define arch_atomic64_fetch_xor(i,v)	ia64_atomic64_fetch_xor(i,v)
-
-#undef ATOMIC64_OPS
-#undef ATOMIC64_FETCH_OP
-#undef ATOMIC64_OP
-
-#define arch_atomic_add(i,v)		(void)arch_atomic_add_return((i), (v))
-#define arch_atomic_sub(i,v)		(void)arch_atomic_sub_return((i), (v))
-
-#define arch_atomic64_add(i,v)		(void)arch_atomic64_add_return((i), (v))
-#define arch_atomic64_sub(i,v)		(void)arch_atomic64_sub_return((i), (v))
-
-#endif /* _ASM_IA64_ATOMIC_H */