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The Itanium architecture is obsolete, and an informal survey [0] reveals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, 271 deletions

diff --git a/arch/ia64/include/asm/io.h b/arch/ia64/include/asm/io.h
deleted file mode 100644
index eedc0afa8cad..000000000000
--- a/arch/ia64/include/asm/io.h
+++ /dev/null
@@ -1,271 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_IA64_IO_H
-#define _ASM_IA64_IO_H
-
-/*
- * This file contains the definitions for the emulated IO instructions
- * inb/inw/inl/outb/outw/outl and the "string versions" of the same
- * (insb/insw/insl/outsb/outsw/outsl). You can also use "pausing"
- * versions of the single-IO instructions (inb_p/inw_p/..).
- *
- * This file is not meant to be obfuscating: it's just complicated to
- * (a) handle it all in a way that makes gcc able to optimize it as
- * well as possible and (b) trying to avoid writing the same thing
- * over and over again with slight variations and possibly making a
- * mistake somewhere.
- *
- * Copyright (C) 1998-2003 Hewlett-Packard Co
- *	David Mosberger-Tang <davidm@hpl.hp.com>
- * Copyright (C) 1999 Asit Mallick <asit.k.mallick@intel.com>
- * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
- */
-
-#include <asm/unaligned.h>
-#include <asm/early_ioremap.h>
-
-#define __IA64_UNCACHED_OFFSET	RGN_BASE(RGN_UNCACHED)
-
-/*
- * The legacy I/O space defined by the ia64 architecture supports only 65536 ports, but
- * large machines may have multiple other I/O spaces so we can't place any a priori limit
- * on IO_SPACE_LIMIT.  These additional spaces are described in ACPI.
- */
-#define IO_SPACE_LIMIT		0xffffffffffffffffUL
-
-#define MAX_IO_SPACES_BITS		8
-#define MAX_IO_SPACES			(1UL << MAX_IO_SPACES_BITS)
-#define IO_SPACE_BITS			24
-#define IO_SPACE_SIZE			(1UL << IO_SPACE_BITS)
-
-#define IO_SPACE_NR(port)		((port) >> IO_SPACE_BITS)
-#define IO_SPACE_BASE(space)		((space) << IO_SPACE_BITS)
-#define IO_SPACE_PORT(port)		((port) & (IO_SPACE_SIZE - 1))
-
-#define IO_SPACE_SPARSE_ENCODING(p)	((((p) >> 2) << 12) | ((p) & 0xfff))
-
-struct io_space {
-	unsigned long mmio_base;	/* base in MMIO space */
-	int sparse;
-};
-
-extern struct io_space io_space[];
-extern unsigned int num_io_spaces;
-
-# ifdef __KERNEL__
-
-/*
- * All MMIO iomem cookies are in region 6; anything less is a PIO cookie:
- *	0xCxxxxxxxxxxxxxxx	MMIO cookie (return from ioremap)
- *	0x000000001SPPPPPP	PIO cookie (S=space number, P..P=port)
- *
- * ioread/writeX() uses the leading 1 in PIO cookies (PIO_OFFSET) to catch
- * code that uses bare port numbers without the prerequisite pci_iomap().
- */
-#define PIO_OFFSET		(1UL << (MAX_IO_SPACES_BITS + IO_SPACE_BITS))
-#define PIO_MASK		(PIO_OFFSET - 1)
-#define PIO_RESERVED		__IA64_UNCACHED_OFFSET
-#define HAVE_ARCH_PIO_SIZE
-
-#include <asm/intrinsics.h>
-#include <asm/page.h>
-#include <asm-generic/iomap.h>
-
-/*
- * Change virtual addresses to physical addresses and vv.
- */
-static inline unsigned long
-virt_to_phys (volatile void *address)
-{
-	return (unsigned long) address - PAGE_OFFSET;
-}
-#define virt_to_phys virt_to_phys
-
-static inline void*
-phys_to_virt (unsigned long address)
-{
-	return (void *) (address + PAGE_OFFSET);
-}
-#define phys_to_virt phys_to_virt
-
-#define ARCH_HAS_VALID_PHYS_ADDR_RANGE
-extern u64 kern_mem_attribute (unsigned long phys_addr, unsigned long size);
-extern int valid_phys_addr_range (phys_addr_t addr, size_t count); /* efi.c */
-extern int valid_mmap_phys_addr_range (unsigned long pfn, size_t count);
-
-# endif /* KERNEL */
-
-/*
- * Memory fence w/accept.  This should never be used in code that is
- * not IA-64 specific.
- */
-#define __ia64_mf_a()	ia64_mfa()
-
-static inline void*
-__ia64_mk_io_addr (unsigned long port)
-{
-	struct io_space *space;
-	unsigned long offset;
-
-	space = &io_space[IO_SPACE_NR(port)];
-	port = IO_SPACE_PORT(port);
-	if (space->sparse)
-		offset = IO_SPACE_SPARSE_ENCODING(port);
-	else
-		offset = port;
-
-	return (void *) (space->mmio_base | offset);
-}
-
-/*
- * For the in/out routines, we need to do "mf.a" _after_ doing the I/O access to ensure
- * that the access has completed before executing other I/O accesses.  Since we're doing
- * the accesses through an uncachable (UC) translation, the CPU will execute them in
- * program order.  However, we still need to tell the compiler not to shuffle them around
- * during optimization, which is why we use "volatile" pointers.
- */
-
-#define inb inb
-static inline unsigned int inb(unsigned long port)
-{
-	volatile unsigned char *addr = __ia64_mk_io_addr(port);
-	unsigned char ret;
-
-	ret = *addr;
-	__ia64_mf_a();
-	return ret;
-}
-
-#define inw inw
-static inline unsigned int inw(unsigned long port)
-{
-	volatile unsigned short *addr = __ia64_mk_io_addr(port);
-	unsigned short ret;
-
-	ret = *addr;
-	__ia64_mf_a();
-	return ret;
-}
-
-#define inl inl
-static inline unsigned int inl(unsigned long port)
-{
-	volatile unsigned int *addr = __ia64_mk_io_addr(port);
-	unsigned int ret;
-
-	ret = *addr;
-	__ia64_mf_a();
-	return ret;
-}
-
-#define outb outb
-static inline void outb(unsigned char val, unsigned long port)
-{
-	volatile unsigned char *addr = __ia64_mk_io_addr(port);
-
-	*addr = val;
-	__ia64_mf_a();
-}
-
-#define outw outw
-static inline void outw(unsigned short val, unsigned long port)
-{
-	volatile unsigned short *addr = __ia64_mk_io_addr(port);
-
-	*addr = val;
-	__ia64_mf_a();
-}
-
-#define outl outl
-static inline void outl(unsigned int val, unsigned long port)
-{
-	volatile unsigned int *addr = __ia64_mk_io_addr(port);
-
-	*addr = val;
-	__ia64_mf_a();
-}
-
-#define insb insb
-static inline void insb(unsigned long port, void *dst, unsigned long count)
-{
-	unsigned char *dp = dst;
-
-	while (count--)
-		*dp++ = inb(port);
-}
-
-#define insw insw
-static inline void insw(unsigned long port, void *dst, unsigned long count)
-{
-	unsigned short *dp = dst;
-
-	while (count--)
-		put_unaligned(inw(port), dp++);
-}
-
-#define insl insl
-static inline void insl(unsigned long port, void *dst, unsigned long count)
-{
-	unsigned int *dp = dst;
-
-	while (count--)
-		put_unaligned(inl(port), dp++);
-}
-
-#define outsb outsb
-static inline void outsb(unsigned long port, const void *src,
-		unsigned long count)
-{
-	const unsigned char *sp = src;
-
-	while (count--)
-		outb(*sp++, port);
-}
-
-#define outsw outsw
-static inline void outsw(unsigned long port, const void *src,
-		unsigned long count)
-{
-	const unsigned short *sp = src;
-
-	while (count--)
-		outw(get_unaligned(sp++), port);
-}
-
-#define outsl outsl
-static inline void outsl(unsigned long port, const void *src,
-		unsigned long count)
-{
-	const unsigned int *sp = src;
-
-	while (count--)
-		outl(get_unaligned(sp++), port);
-}
-
-# ifdef __KERNEL__
-
-#define _PAGE_IOREMAP pgprot_val(PAGE_KERNEL)
-
-extern void __iomem * ioremap_uc(unsigned long offset, unsigned long size);
-
-#define ioremap_prot ioremap_prot
-#define ioremap_cache ioremap
-#define ioremap_uc ioremap_uc
-#define iounmap iounmap
-
-/*
- * String version of IO memory access ops:
- */
-extern void memcpy_fromio(void *dst, const volatile void __iomem *src, long n);
-extern void memcpy_toio(volatile void __iomem *dst, const void *src, long n);
-extern void memset_io(volatile void __iomem *s, int c, long n);
-
-#define memcpy_fromio memcpy_fromio
-#define memcpy_toio memcpy_toio
-#define memset_io memset_io
-#define xlate_dev_mem_ptr xlate_dev_mem_ptr
-#include <asm-generic/io.h>
-#undef PCI_IOBASE
-
-# endif /* __KERNEL__ */
-
-#endif /* _ASM_IA64_IO_H */