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The Itanium architecture is obsolete, and an informal survey [0] reveals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

3 files changed, 0 insertions, 163 deletions

diff --git a/arch/ia64/include/asm/native/inst.h b/arch/ia64/include/asm/native/inst.h
deleted file mode 100644
index e08662396029..000000000000
--- a/arch/ia64/include/asm/native/inst.h
+++ /dev/null
@@ -1,119 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/******************************************************************************
- * arch/ia64/include/asm/native/inst.h
- *
- * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
- *                    VA Linux Systems Japan K.K.
- */
-
-#define DO_SAVE_MIN		IA64_NATIVE_DO_SAVE_MIN
-
-#define MOV_FROM_IFA(reg)	\
-	mov reg = cr.ifa
-
-#define MOV_FROM_ITIR(reg)	\
-	mov reg = cr.itir
-
-#define MOV_FROM_ISR(reg)	\
-	mov reg = cr.isr
-
-#define MOV_FROM_IHA(reg)	\
-	mov reg = cr.iha
-
-#define MOV_FROM_IPSR(pred, reg)	\
-(pred)	mov reg = cr.ipsr
-
-#define MOV_FROM_IIM(reg)	\
-	mov reg = cr.iim
-
-#define MOV_FROM_IIP(reg)	\
-	mov reg = cr.iip
-
-#define MOV_FROM_IVR(reg, clob)	\
-	mov reg = cr.ivr
-
-#define MOV_FROM_PSR(pred, reg, clob)	\
-(pred)	mov reg = psr
-
-#define MOV_FROM_ITC(pred, pred_clob, reg, clob)	\
-(pred)	mov reg = ar.itc
-
-#define MOV_TO_IFA(reg, clob)	\
-	mov cr.ifa = reg
-
-#define MOV_TO_ITIR(pred, reg, clob)	\
-(pred)	mov cr.itir = reg
-
-#define MOV_TO_IHA(pred, reg, clob)	\
-(pred)	mov cr.iha = reg
-
-#define MOV_TO_IPSR(pred, reg, clob)		\
-(pred)	mov cr.ipsr = reg
-
-#define MOV_TO_IFS(pred, reg, clob)	\
-(pred)	mov cr.ifs = reg
-
-#define MOV_TO_IIP(reg, clob)	\
-	mov cr.iip = reg
-
-#define MOV_TO_KR(kr, reg, clob0, clob1)	\
-	mov IA64_KR(kr) = reg
-
-#define ITC_I(pred, reg, clob)	\
-(pred)	itc.i reg
-
-#define ITC_D(pred, reg, clob)	\
-(pred)	itc.d reg
-
-#define ITC_I_AND_D(pred_i, pred_d, reg, clob)	\
-(pred_i) itc.i reg;				\
-(pred_d) itc.d reg
-
-#define THASH(pred, reg0, reg1, clob)		\
-(pred)	thash reg0 = reg1
-
-#define SSM_PSR_IC_AND_DEFAULT_BITS_AND_SRLZ_I(clob0, clob1)		\
-	ssm psr.ic | PSR_DEFAULT_BITS					\
-	;;								\
-	srlz.i /* guarantee that interruption collectin is on */	\
-	;;
-
-#define SSM_PSR_IC_AND_SRLZ_D(clob0, clob1)	\
-	ssm psr.ic				\
-	;;					\
-	srlz.d
-
-#define RSM_PSR_IC(clob)	\
-	rsm psr.ic
-
-#define SSM_PSR_I(pred, pred_clob, clob)	\
-(pred)	ssm psr.i
-
-#define RSM_PSR_I(pred, clob0, clob1)	\
-(pred)	rsm psr.i
-
-#define RSM_PSR_I_IC(clob0, clob1, clob2)	\
-	rsm psr.i | psr.ic
-
-#define RSM_PSR_DT		\
-	rsm psr.dt
-
-#define RSM_PSR_BE_I(clob0, clob1)	\
-	rsm psr.be | psr.i
-
-#define SSM_PSR_DT_AND_SRLZ_I	\
-	ssm psr.dt		\
-	;;			\
-	srlz.i
-
-#define BSW_0(clob0, clob1, clob2)	\
-	bsw.0
-
-#define BSW_1(clob0, clob1)	\
-	bsw.1
-
-#define COVER	\
-	cover
-
-#define RFI	\
-	rfi
diff --git a/arch/ia64/include/asm/native/irq.h b/arch/ia64/include/asm/native/irq.h
deleted file mode 100644
index aa74915f8aa2..000000000000
--- a/arch/ia64/include/asm/native/irq.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/******************************************************************************
- * arch/ia64/include/asm/native/irq.h
- *
- * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
- *                    VA Linux Systems Japan K.K.
- */
-
-#ifndef _ASM_IA64_NATIVE_IRQ_H
-#define _ASM_IA64_NATIVE_IRQ_H
-
-#define NR_VECTORS	256
-
-#if (NR_VECTORS + 32 * NR_CPUS) < 1024
-#define IA64_NATIVE_NR_IRQS (NR_VECTORS + 32 * NR_CPUS)
-#else
-#define IA64_NATIVE_NR_IRQS 1024
-#endif
-
-#endif /* _ASM_IA64_NATIVE_IRQ_H */
diff --git a/arch/ia64/include/asm/native/patchlist.h b/arch/ia64/include/asm/native/patchlist.h
deleted file mode 100644
index f13e7675758c..000000000000
--- a/arch/ia64/include/asm/native/patchlist.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/******************************************************************************
- * arch/ia64/include/asm/native/inst.h
- *
- * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
- *                    VA Linux Systems Japan K.K.
- */
-
-#define __paravirt_start_gate_fsyscall_patchlist		\
-	__ia64_native_start_gate_fsyscall_patchlist
-#define __paravirt_end_gate_fsyscall_patchlist			\
-	__ia64_native_end_gate_fsyscall_patchlist
-#define __paravirt_start_gate_brl_fsys_bubble_down_patchlist	\
-	__ia64_native_start_gate_brl_fsys_bubble_down_patchlist
-#define __paravirt_end_gate_brl_fsys_bubble_down_patchlist	\
-	__ia64_native_end_gate_brl_fsys_bubble_down_patchlist
-#define __paravirt_start_gate_vtop_patchlist			\
-	__ia64_native_start_gate_vtop_patchlist
-#define __paravirt_end_gate_vtop_patchlist			\
-	__ia64_native_end_gate_vtop_patchlist
-#define __paravirt_start_gate_mckinley_e9_patchlist		\
-	__ia64_native_start_gate_mckinley_e9_patchlist
-#define __paravirt_end_gate_mckinley_e9_patchlist		\
-	__ia64_native_end_gate_mckinley_e9_patchlist