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The Itanium architecture is obsolete, and an informal survey [0] reveals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, 123 deletions

diff --git a/arch/ia64/kernel/mca_drv.h b/arch/ia64/kernel/mca_drv.h
deleted file mode 100644
index 45bc4e3ae14f..000000000000
--- a/arch/ia64/kernel/mca_drv.h
+++ /dev/null
@@ -1,123 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * File:	mca_drv.h
- * Purpose:	Define helpers for Generic MCA handling
- *
- * Copyright (C) 2004 FUJITSU LIMITED
- * Copyright (C) 2004 Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
- */
-/*
- * Processor error section:
- *
- *  +-sal_log_processor_info_t *info-------------+
- *  | sal_log_section_hdr_t header;              |
- *  | ...                                        |
- *  | sal_log_mod_error_info_t info[0];          |
- *  +-+----------------+-------------------------+
- *    | CACHE_CHECK    |  ^ num_cache_check v
- *    +----------------+
- *    | TLB_CHECK      |  ^ num_tlb_check v
- *    +----------------+
- *    | BUS_CHECK      |  ^ num_bus_check v
- *    +----------------+
- *    | REG_FILE_CHECK |  ^ num_reg_file_check v
- *    +----------------+
- *    | MS_CHECK       |  ^ num_ms_check v
- *  +-struct cpuid_info *id----------------------+
- *  | regs[5];                                   |
- *  | reserved;                                  |
- *  +-sal_processor_static_info_t *regs----------+
- *  | valid;                                     |
- *  | ...                                        |
- *  | fr[128];                                   |
- *  +--------------------------------------------+
- */
-
-/* peidx: index of processor error section */
-typedef struct peidx_table {
-	sal_log_processor_info_t        *info;
-	struct sal_cpuid_info           *id;
-	sal_processor_static_info_t     *regs;
-} peidx_table_t;
-
-#define peidx_head(p)   (((p)->info))
-#define peidx_mid(p)    (((p)->id))
-#define peidx_bottom(p) (((p)->regs))
-
-#define peidx_psp(p)           (&(peidx_head(p)->proc_state_parameter))
-#define peidx_field_valid(p)   (&(peidx_head(p)->valid))
-#define peidx_minstate_area(p) (&(peidx_bottom(p)->min_state_area))
-
-#define peidx_cache_check_num(p)    (peidx_head(p)->valid.num_cache_check)
-#define peidx_tlb_check_num(p)      (peidx_head(p)->valid.num_tlb_check)
-#define peidx_bus_check_num(p)      (peidx_head(p)->valid.num_bus_check)
-#define peidx_reg_file_check_num(p) (peidx_head(p)->valid.num_reg_file_check)
-#define peidx_ms_check_num(p)       (peidx_head(p)->valid.num_ms_check)
-
-#define peidx_cache_check_idx(p, n)    (n)
-#define peidx_tlb_check_idx(p, n)      (peidx_cache_check_idx(p, peidx_cache_check_num(p)) + n)
-#define peidx_bus_check_idx(p, n)      (peidx_tlb_check_idx(p, peidx_tlb_check_num(p)) + n)
-#define peidx_reg_file_check_idx(p, n) (peidx_bus_check_idx(p, peidx_bus_check_num(p)) + n)
-#define peidx_ms_check_idx(p, n)       (peidx_reg_file_check_idx(p, peidx_reg_file_check_num(p)) + n)
-
-#define peidx_mod_error_info(p, name, n) \
-({	int __idx = peidx_##name##_idx(p, n); \
-	sal_log_mod_error_info_t *__ret = NULL; \
-	if (peidx_##name##_num(p) > n) /*BUG*/ \
-		__ret = &(peidx_head(p)->info[__idx]); \
-	__ret; })
-
-#define peidx_cache_check(p, n)    peidx_mod_error_info(p, cache_check, n)
-#define peidx_tlb_check(p, n)      peidx_mod_error_info(p, tlb_check, n)
-#define peidx_bus_check(p, n)      peidx_mod_error_info(p, bus_check, n)
-#define peidx_reg_file_check(p, n) peidx_mod_error_info(p, reg_file_check, n)
-#define peidx_ms_check(p, n)       peidx_mod_error_info(p, ms_check, n)
-
-#define peidx_check_info(proc, name, n) \
-({ \
-	sal_log_mod_error_info_t *__info = peidx_mod_error_info(proc, name, n);\
-	u64 __temp = __info && __info->valid.check_info \
-		? __info->check_info : 0; \
-	__temp; })
-
-/* slidx: index of SAL log error record */
-
-typedef struct slidx_list {
-	struct list_head list;
-	sal_log_section_hdr_t *hdr;
-} slidx_list_t;
-
-typedef struct slidx_table {
-	sal_log_record_header_t *header;
-	int n_sections;			/* # of section headers */
-	struct list_head proc_err;
-	struct list_head mem_dev_err;
-	struct list_head sel_dev_err;
-	struct list_head pci_bus_err;
-	struct list_head smbios_dev_err;
-	struct list_head pci_comp_err;
-	struct list_head plat_specific_err;
-	struct list_head host_ctlr_err;
-	struct list_head plat_bus_err;
-	struct list_head unsupported;	/* list of unsupported sections */
-} slidx_table_t;
-
-#define slidx_foreach_entry(pos, head) \
-	list_for_each_entry(pos, head, list)
-#define slidx_first_entry(head) \
-	(((head)->next != (head)) ? list_entry((head)->next, typeof(slidx_list_t), list) : NULL)
-#define slidx_count(slidx, sec) \
-({	int __count = 0; \
-	slidx_list_t *__pos; \
-	slidx_foreach_entry(__pos, &((slidx)->sec)) { __count++; }\
-	__count; })
-
-struct mca_table_entry {
-	int start_addr;	/* location-relative starting address of MCA recoverable range */
-	int end_addr;	/* location-relative ending address of MCA recoverable range */
-};
-
-extern const struct mca_table_entry *search_mca_tables (unsigned long addr);
-extern int mca_recover_range(unsigned long);
-extern void ia64_mlogbuf_dump(void);
-