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cf8e865810
The Itanium architecture is obsolete, and an informal survey [0] reveals that any residual use of Itanium hardware in production is mostly HP-UX or OpenVMS based.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>
76 lines
2.1 KiB
C
76 lines
2.1 KiB
C
/*
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* Copyright (c) 2008 Silicon Graphics, Inc. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __GRU_H__
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#define __GRU_H__
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/*
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* GRU architectural definitions
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*/
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#define GRU_CACHE_LINE_BYTES 64
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#define GRU_HANDLE_STRIDE 256
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#define GRU_CB_BASE 0
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#define GRU_DS_BASE 0x20000
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/*
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* Size used to map GRU GSeg
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*/
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#if defined(CONFIG_X86_64)
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#define GRU_GSEG_PAGESIZE (256 * 1024UL) /* ZZZ 2MB ??? */
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#else
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#error "Unsupported architecture"
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#endif
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/*
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* Structure for obtaining GRU resource information
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*/
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struct gru_chiplet_info {
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int node;
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int chiplet;
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int blade;
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int total_dsr_bytes;
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int total_cbr;
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int total_user_dsr_bytes;
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int total_user_cbr;
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int free_user_dsr_bytes;
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int free_user_cbr;
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};
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/*
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* Statictics kept for each context.
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*/
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struct gru_gseg_statistics {
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unsigned long fmm_tlbmiss;
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unsigned long upm_tlbmiss;
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unsigned long tlbdropin;
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unsigned long context_stolen;
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unsigned long reserved[10];
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};
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/* Flags for GRU options on the gru_create_context() call */
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/* Select one of the follow 4 options to specify how TLB misses are handled */
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#define GRU_OPT_MISS_DEFAULT 0x0000 /* Use default mode */
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#define GRU_OPT_MISS_USER_POLL 0x0001 /* User will poll CB for faults */
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#define GRU_OPT_MISS_FMM_INTR 0x0002 /* Send interrupt to cpu to
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handle fault */
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#define GRU_OPT_MISS_FMM_POLL 0x0003 /* Use system polling thread */
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#define GRU_OPT_MISS_MASK 0x0003 /* Mask for TLB MISS option */
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#endif /* __GRU_H__ */
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