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The Itanium architecture is obsolete, and an informal survey [0] reveals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, 365 deletions

diff --git a/arch/ia64/lib/memset.S b/arch/ia64/lib/memset.S
deleted file mode 100644
index 552c5c7e4d06..000000000000
--- a/arch/ia64/lib/memset.S
+++ /dev/null
@@ -1,365 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/* Optimized version of the standard memset() function.
-
-   Copyright (c) 2002 Hewlett-Packard Co/CERN
-	Sverre Jarp <Sverre.Jarp@cern.ch>
-
-   Return: dest
-
-   Inputs:
-        in0:    dest
-        in1:    value
-        in2:    count
-
-   The algorithm is fairly straightforward: set byte by byte until we
-   we get to a 16B-aligned address, then loop on 128 B chunks using an
-   early store as prefetching, then loop on 32B chucks, then clear remaining
-   words, finally clear remaining bytes.
-   Since a stf.spill f0 can store 16B in one go, we use this instruction
-   to get peak speed when value = 0.  */
-
-#include <linux/export.h>
-#include <asm/asmmacro.h>
-#undef ret
-
-#define dest		in0
-#define value		in1
-#define	cnt		in2
-
-#define tmp		r31
-#define save_lc		r30
-#define ptr0		r29
-#define ptr1		r28
-#define ptr2		r27
-#define ptr3		r26
-#define ptr9 		r24
-#define	loopcnt		r23
-#define linecnt		r22
-#define bytecnt		r21
-
-#define fvalue		f6
-
-// This routine uses only scratch predicate registers (p6 - p15)
-#define p_scr		p6			// default register for same-cycle branches
-#define p_nz		p7
-#define p_zr		p8
-#define p_unalgn	p9
-#define p_y		p11
-#define p_n		p12
-#define p_yy		p13
-#define p_nn		p14
-
-#define MIN1		15
-#define MIN1P1HALF	8
-#define LINE_SIZE	128
-#define LSIZE_SH        7			// shift amount
-#define PREF_AHEAD	8
-
-GLOBAL_ENTRY(memset)
-{ .mmi
-	.prologue
-	alloc	tmp = ar.pfs, 3, 0, 0, 0
-	lfetch.nt1 [dest]			//
-	.save   ar.lc, save_lc
-	mov.i	save_lc = ar.lc
-	.body
-} { .mmi
-	mov	ret0 = dest			// return value
-	cmp.ne	p_nz, p_zr = value, r0		// use stf.spill if value is zero
-	cmp.eq	p_scr, p0 = cnt, r0
-;; }
-{ .mmi
-	and	ptr2 = -(MIN1+1), dest		// aligned address
-	and	tmp = MIN1, dest		// prepare to check for correct alignment
-	tbit.nz p_y, p_n = dest, 0		// Do we have an odd address? (M_B_U)
-} { .mib
-	mov	ptr1 = dest
-	mux1	value = value, @brcst		// create 8 identical bytes in word
-(p_scr)	br.ret.dpnt.many rp			// return immediately if count = 0
-;; }
-{ .mib
-	cmp.ne	p_unalgn, p0 = tmp, r0		//
-} { .mib
-	sub	bytecnt = (MIN1+1), tmp		// NB: # of bytes to move is 1 higher than loopcnt
-	cmp.gt	p_scr, p0 = 16, cnt		// is it a minimalistic task?
-(p_scr)	br.cond.dptk.many .move_bytes_unaligned	// go move just a few (M_B_U)
-;; }
-{ .mmi
-(p_unalgn) add	ptr1 = (MIN1+1), ptr2		// after alignment
-(p_unalgn) add	ptr2 = MIN1P1HALF, ptr2		// after alignment
-(p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 3	// should we do a st8 ?
-;; }
-{ .mib
-(p_y)	add	cnt = -8, cnt			//
-(p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 2	// should we do a st4 ?
-} { .mib
-(p_y)	st8	[ptr2] = value,-4		//
-(p_n)	add	ptr2 = 4, ptr2			//
-;; }
-{ .mib
-(p_yy)	add	cnt = -4, cnt			//
-(p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 1	// should we do a st2 ?
-} { .mib
-(p_yy)	st4	[ptr2] = value,-2		//
-(p_nn)	add	ptr2 = 2, ptr2			//
-;; }
-{ .mmi
-	mov	tmp = LINE_SIZE+1		// for compare
-(p_y)	add	cnt = -2, cnt			//
-(p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 0	// should we do a st1 ?
-} { .mmi
-	setf.sig fvalue=value			// transfer value to FLP side
-(p_y)	st2	[ptr2] = value,-1		//
-(p_n)	add	ptr2 = 1, ptr2			//
-;; }
-
-{ .mmi
-(p_yy)	st1	[ptr2] = value 			//
-  	cmp.gt	p_scr, p0 = tmp, cnt		// is it a minimalistic task?
-} { .mbb
-(p_yy)	add	cnt = -1, cnt			//
-(p_scr)	br.cond.dpnt.many .fraction_of_line	// go move just a few
-;; }
-
-{ .mib
-	nop.m 0
-	shr.u	linecnt = cnt, LSIZE_SH
-(p_zr)	br.cond.dptk.many .l1b			// Jump to use stf.spill
-;; }
-
-	TEXT_ALIGN(32) // --------------------- //  L1A: store ahead into cache lines; fill later
-{ .mmi
-	and	tmp = -(LINE_SIZE), cnt		// compute end of range
-	mov	ptr9 = ptr1			// used for prefetching
-	and	cnt = (LINE_SIZE-1), cnt	// remainder
-} { .mmi
-	mov	loopcnt = PREF_AHEAD-1		// default prefetch loop
-	cmp.gt	p_scr, p0 = PREF_AHEAD, linecnt	// check against actual value
-;; }
-{ .mmi
-(p_scr)	add	loopcnt = -1, linecnt		//
-	add	ptr2 = 8, ptr1			// start of stores (beyond prefetch stores)
-	add	ptr1 = tmp, ptr1		// first address beyond total range
-;; }
-{ .mmi
-	add	tmp = -1, linecnt		// next loop count
-	mov.i	ar.lc = loopcnt			//
-;; }
-.pref_l1a:
-{ .mib
-	stf8 [ptr9] = fvalue, 128		// Do stores one cache line apart
-	nop.i	0
-	br.cloop.dptk.few .pref_l1a
-;; }
-{ .mmi
-	add	ptr0 = 16, ptr2			// Two stores in parallel
-	mov.i	ar.lc = tmp			//
-;; }
-.l1ax:
- { .mmi
-	stf8 [ptr2] = fvalue, 8
-	stf8 [ptr0] = fvalue, 8
- ;; }
- { .mmi
-	stf8 [ptr2] = fvalue, 24
-	stf8 [ptr0] = fvalue, 24
- ;; }
- { .mmi
-	stf8 [ptr2] = fvalue, 8
-	stf8 [ptr0] = fvalue, 8
- ;; }
- { .mmi
-	stf8 [ptr2] = fvalue, 24
-	stf8 [ptr0] = fvalue, 24
- ;; }
- { .mmi
-	stf8 [ptr2] = fvalue, 8
-	stf8 [ptr0] = fvalue, 8
- ;; }
- { .mmi
-	stf8 [ptr2] = fvalue, 24
-	stf8 [ptr0] = fvalue, 24
- ;; }
- { .mmi
-	stf8 [ptr2] = fvalue, 8
-	stf8 [ptr0] = fvalue, 32
- 	cmp.lt	p_scr, p0 = ptr9, ptr1		// do we need more prefetching?
- ;; }
-{ .mmb
-	stf8 [ptr2] = fvalue, 24
-(p_scr)	stf8 [ptr9] = fvalue, 128
-	br.cloop.dptk.few .l1ax
-;; }
-{ .mbb
-	cmp.le  p_scr, p0 = 8, cnt		// just a few bytes left ?
-(p_scr) br.cond.dpnt.many  .fraction_of_line	// Branch no. 2
-	br.cond.dpnt.many  .move_bytes_from_alignment	// Branch no. 3
-;; }
-
-	TEXT_ALIGN(32)
-.l1b:	// ------------------------------------ //  L1B: store ahead into cache lines; fill later
-{ .mmi
-	and	tmp = -(LINE_SIZE), cnt		// compute end of range
-	mov	ptr9 = ptr1			// used for prefetching
-	and	cnt = (LINE_SIZE-1), cnt	// remainder
-} { .mmi
-	mov	loopcnt = PREF_AHEAD-1		// default prefetch loop
-	cmp.gt	p_scr, p0 = PREF_AHEAD, linecnt	// check against actual value
-;; }
-{ .mmi
-(p_scr)	add	loopcnt = -1, linecnt
-	add	ptr2 = 16, ptr1			// start of stores (beyond prefetch stores)
-	add	ptr1 = tmp, ptr1		// first address beyond total range
-;; }
-{ .mmi
-	add	tmp = -1, linecnt		// next loop count
-	mov.i	ar.lc = loopcnt
-;; }
-.pref_l1b:
-{ .mib
-	stf.spill [ptr9] = f0, 128		// Do stores one cache line apart
-	nop.i   0
-	br.cloop.dptk.few .pref_l1b
-;; }
-{ .mmi
-	add	ptr0 = 16, ptr2			// Two stores in parallel
-	mov.i	ar.lc = tmp
-;; }
-.l1bx:
- { .mmi
-	stf.spill [ptr2] = f0, 32
-	stf.spill [ptr0] = f0, 32
- ;; }
- { .mmi
-	stf.spill [ptr2] = f0, 32
-	stf.spill [ptr0] = f0, 32
- ;; }
- { .mmi
-	stf.spill [ptr2] = f0, 32
-	stf.spill [ptr0] = f0, 64
- 	cmp.lt	p_scr, p0 = ptr9, ptr1		// do we need more prefetching?
- ;; }
-{ .mmb
-	stf.spill [ptr2] = f0, 32
-(p_scr)	stf.spill [ptr9] = f0, 128
-	br.cloop.dptk.few .l1bx
-;; }
-{ .mib
-	cmp.gt  p_scr, p0 = 8, cnt		// just a few bytes left ?
-(p_scr)	br.cond.dpnt.many  .move_bytes_from_alignment	//
-;; }
-
-.fraction_of_line:
-{ .mib
-	add	ptr2 = 16, ptr1
-	shr.u	loopcnt = cnt, 5   		// loopcnt = cnt / 32
-;; }
-{ .mib
-	cmp.eq	p_scr, p0 = loopcnt, r0
-	add	loopcnt = -1, loopcnt
-(p_scr)	br.cond.dpnt.many .store_words
-;; }
-{ .mib
-	and	cnt = 0x1f, cnt			// compute the remaining cnt
-	mov.i   ar.lc = loopcnt
-;; }
-	TEXT_ALIGN(32)
-.l2:	// ------------------------------------ //  L2A:  store 32B in 2 cycles
-{ .mmb
-	stf8	[ptr1] = fvalue, 8
-	stf8	[ptr2] = fvalue, 8
-;; } { .mmb
-	stf8	[ptr1] = fvalue, 24
-	stf8	[ptr2] = fvalue, 24
-	br.cloop.dptk.many .l2
-;; }
-.store_words:
-{ .mib
-	cmp.gt	p_scr, p0 = 8, cnt		// just a few bytes left ?
-(p_scr)	br.cond.dpnt.many .move_bytes_from_alignment	// Branch
-;; }
-
-{ .mmi
-	stf8	[ptr1] = fvalue, 8		// store
-	cmp.le	p_y, p_n = 16, cnt
-	add	cnt = -8, cnt			// subtract
-;; }
-{ .mmi
-(p_y)	stf8	[ptr1] = fvalue, 8		// store
-(p_y)	cmp.le.unc p_yy, p_nn = 16, cnt
-(p_y)	add	cnt = -8, cnt			// subtract
-;; }
-{ .mmi						// store
-(p_yy)	stf8	[ptr1] = fvalue, 8
-(p_yy)	add	cnt = -8, cnt			// subtract
-;; }
-
-.move_bytes_from_alignment:
-{ .mib
-	cmp.eq	p_scr, p0 = cnt, r0
-	tbit.nz.unc p_y, p0 = cnt, 2		// should we terminate with a st4 ?
-(p_scr)	br.cond.dpnt.few .restore_and_exit
-;; }
-{ .mib
-(p_y)	st4	[ptr1] = value,4
-	tbit.nz.unc p_yy, p0 = cnt, 1		// should we terminate with a st2 ?
-;; }
-{ .mib
-(p_yy)	st2	[ptr1] = value,2
-	tbit.nz.unc p_y, p0 = cnt, 0		// should we terminate with a st1 ?
-;; }
-
-{ .mib
-(p_y)	st1	[ptr1] = value
-;; }
-.restore_and_exit:
-{ .mib
-	nop.m	0
-	mov.i	ar.lc = save_lc
-	br.ret.sptk.many rp
-;; }
-
-.move_bytes_unaligned:
-{ .mmi
-       .pred.rel "mutex",p_y, p_n
-       .pred.rel "mutex",p_yy, p_nn
-(p_n)	cmp.le  p_yy, p_nn = 4, cnt
-(p_y)	cmp.le  p_yy, p_nn = 5, cnt
-(p_n)	add	ptr2 = 2, ptr1
-} { .mmi
-(p_y)	add	ptr2 = 3, ptr1
-(p_y)	st1	[ptr1] = value, 1		// fill 1 (odd-aligned) byte [15, 14 (or less) left]
-(p_y)	add	cnt = -1, cnt
-;; }
-{ .mmi
-(p_yy)	cmp.le.unc p_y, p0 = 8, cnt
-	add	ptr3 = ptr1, cnt		// prepare last store
-	mov.i	ar.lc = save_lc
-} { .mmi
-(p_yy)	st2	[ptr1] = value, 4		// fill 2 (aligned) bytes
-(p_yy)	st2	[ptr2] = value, 4		// fill 2 (aligned) bytes [11, 10 (o less) left]
-(p_yy)	add	cnt = -4, cnt
-;; }
-{ .mmi
-(p_y)	cmp.le.unc p_yy, p0 = 8, cnt
-	add	ptr3 = -1, ptr3			// last store
-	tbit.nz p_scr, p0 = cnt, 1		// will there be a st2 at the end ?
-} { .mmi
-(p_y)	st2	[ptr1] = value, 4		// fill 2 (aligned) bytes
-(p_y)	st2	[ptr2] = value, 4		// fill 2 (aligned) bytes [7, 6 (or less) left]
-(p_y)	add	cnt = -4, cnt
-;; }
-{ .mmi
-(p_yy)	st2	[ptr1] = value, 4		// fill 2 (aligned) bytes
-(p_yy)	st2	[ptr2] = value, 4		// fill 2 (aligned) bytes [3, 2 (or less) left]
-	tbit.nz p_y, p0 = cnt, 0		// will there be a st1 at the end ?
-} { .mmi
-(p_yy)	add	cnt = -4, cnt
-;; }
-{ .mmb
-(p_scr)	st2	[ptr1] = value			// fill 2 (aligned) bytes
-(p_y)	st1	[ptr3] = value			// fill last byte (using ptr3)
-	br.ret.sptk.many rp
-}
-END(memset)
-EXPORT_SYMBOL(memset)