diff options
author | Ard Biesheuvel <ardb@kernel.org> | 2022-10-20 15:54:33 +0200 |
---|---|---|
committer | Ard Biesheuvel <ardb@kernel.org> | 2023-09-11 08:13:17 +0000 |
commit | cf8e8658100d4eae80ce9b21f7a81cb024dd5057 (patch) | |
tree | 31d3b640bebf97c33d354768fc44dfd532c2df81 /arch/ia64/include/asm/futex.h | |
parent | a0334bf78b95532cec54f56b53e8ae1bfe7e1ca1 (diff) |
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The Itanium architecture is obsolete, and an informal survey [0] reveals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>
Diffstat (limited to 'arch/ia64/include/asm/futex.h')
-rw-r--r-- | arch/ia64/include/asm/futex.h | 109 |
1 files changed, 0 insertions, 109 deletions
diff --git a/arch/ia64/include/asm/futex.h b/arch/ia64/include/asm/futex.h deleted file mode 100644 index 1db26b432d8c..000000000000 --- a/arch/ia64/include/asm/futex.h +++ /dev/null @@ -1,109 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_FUTEX_H -#define _ASM_FUTEX_H - -#include <linux/futex.h> -#include <linux/uaccess.h> -#include <asm/errno.h> - -#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \ -do { \ - register unsigned long r8 __asm ("r8") = 0; \ - __asm__ __volatile__( \ - " mf;; \n" \ - "[1:] " insn ";; \n" \ - " .xdata4 \"__ex_table\", 1b-., 2f-. \n" \ - "[2:]" \ - : "+r" (r8), "=r" (oldval) \ - : "r" (uaddr), "r" (oparg) \ - : "memory"); \ - ret = r8; \ -} while (0) - -#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \ -do { \ - register unsigned long r8 __asm ("r8") = 0; \ - int val, newval; \ - do { \ - __asm__ __volatile__( \ - " mf;; \n" \ - "[1:] ld4 %3=[%4];; \n" \ - " mov %2=%3 \n" \ - insn ";; \n" \ - " mov ar.ccv=%2;; \n" \ - "[2:] cmpxchg4.acq %1=[%4],%3,ar.ccv;; \n" \ - " .xdata4 \"__ex_table\", 1b-., 3f-.\n" \ - " .xdata4 \"__ex_table\", 2b-., 3f-.\n" \ - "[3:]" \ - : "+r" (r8), "=r" (val), "=&r" (oldval), \ - "=&r" (newval) \ - : "r" (uaddr), "r" (oparg) \ - : "memory"); \ - if (unlikely (r8)) \ - break; \ - } while (unlikely (val != oldval)); \ - ret = r8; \ -} while (0) - -static inline int -arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) -{ - int oldval = 0, ret; - - if (!access_ok(uaddr, sizeof(u32))) - return -EFAULT; - - switch (op) { - case FUTEX_OP_SET: - __futex_atomic_op1("xchg4 %1=[%2],%3", ret, oldval, uaddr, - oparg); - break; - case FUTEX_OP_ADD: - __futex_atomic_op2("add %3=%3,%5", ret, oldval, uaddr, oparg); - break; - case FUTEX_OP_OR: - __futex_atomic_op2("or %3=%3,%5", ret, oldval, uaddr, oparg); - break; - case FUTEX_OP_ANDN: - __futex_atomic_op2("and %3=%3,%5", ret, oldval, uaddr, - ~oparg); - break; - case FUTEX_OP_XOR: - __futex_atomic_op2("xor %3=%3,%5", ret, oldval, uaddr, oparg); - break; - default: - ret = -ENOSYS; - } - - if (!ret) - *oval = oldval; - - return ret; -} - -static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, - u32 oldval, u32 newval) -{ - if (!access_ok(uaddr, sizeof(u32))) - return -EFAULT; - - { - register unsigned long r8 __asm ("r8") = 0; - unsigned long prev; - __asm__ __volatile__( - " mf;; \n" - " mov ar.ccv=%4;; \n" - "[1:] cmpxchg4.acq %1=[%2],%3,ar.ccv \n" - " .xdata4 \"__ex_table\", 1b-., 2f-. \n" - "[2:]" - : "+r" (r8), "=&r" (prev) - : "r" (uaddr), "r" (newval), - "rO" ((long) (unsigned) oldval) - : "memory"); - *uval = prev; - return r8; - } -} - -#endif /* _ASM_FUTEX_H */ |