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The Itanium architecture is obsolete, and an informal survey [0] reveals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, 394 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
deleted file mode 100644
index 53faa122b0f4..000000000000
--- a/arch/ia64/Kconfig
+++ /dev/null
@@ -1,394 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-config PGTABLE_LEVELS
-	int "Page Table Levels" if !IA64_PAGE_SIZE_64KB
-	range 3 4 if !IA64_PAGE_SIZE_64KB
-	default 3
-
-menu "Processor type and features"
-
-config IA64
-	bool
-	select ARCH_BINFMT_ELF_EXTRA_PHDRS
-	select ARCH_HAS_CPU_FINALIZE_INIT
-	select ARCH_HAS_DMA_MARK_CLEAN
-	select ARCH_HAS_STRNCPY_FROM_USER
-	select ARCH_HAS_STRNLEN_USER
-	select ARCH_MIGHT_HAVE_PC_PARPORT
-	select ARCH_MIGHT_HAVE_PC_SERIO
-	select ACPI
-	select ACPI_NUMA if NUMA
-	select ARCH_ENABLE_MEMORY_HOTPLUG
-	select ARCH_ENABLE_MEMORY_HOTREMOVE
-	select ARCH_SUPPORTS_ACPI
-	select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
-	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
-	select FORCE_PCI
-	select PCI_DOMAINS if PCI
-	select PCI_MSI
-	select PCI_SYSCALL if PCI
-	select HAS_IOPORT
-	select HAVE_ASM_MODVERSIONS
-	select HAVE_UNSTABLE_SCHED_CLOCK
-	select HAVE_EXIT_THREAD
-	select HAVE_KPROBES
-	select HAVE_KRETPROBES
-	select HAVE_FTRACE_MCOUNT_RECORD
-	select HAVE_DYNAMIC_FTRACE if (!ITANIUM)
-	select HAVE_FUNCTION_TRACER
-	select HAVE_SETUP_PER_CPU_AREA
-	select TTY
-	select HAVE_ARCH_TRACEHOOK
-	select HAVE_FUNCTION_DESCRIPTORS
-	select HAVE_VIRT_CPU_ACCOUNTING
-	select HUGETLB_PAGE_SIZE_VARIABLE if HUGETLB_PAGE
-	select GENERIC_IRQ_PROBE
-	select GENERIC_PENDING_IRQ if SMP
-	select GENERIC_IRQ_SHOW
-	select GENERIC_IRQ_LEGACY
-	select ARCH_HAVE_NMI_SAFE_CMPXCHG
-	select GENERIC_IOMAP
-	select GENERIC_IOREMAP
-	select GENERIC_SMP_IDLE_THREAD
-	select ARCH_TASK_STRUCT_ON_STACK
-	select ARCH_TASK_STRUCT_ALLOCATOR
-	select ARCH_THREAD_STACK_ALLOCATOR
-	select ARCH_CLOCKSOURCE_DATA
-	select GENERIC_TIME_VSYSCALL
-	select LEGACY_TIMER_TICK
-	select SWIOTLB
-	select SYSCTL_ARCH_UNALIGN_NO_WARN
-	select HAVE_MOD_ARCH_SPECIFIC
-	select MODULES_USE_ELF_RELA
-	select ARCH_USE_CMPXCHG_LOCKREF
-	select HAVE_ARCH_AUDITSYSCALL
-	select NEED_DMA_MAP_STATE
-	select NEED_SG_DMA_LENGTH
-	select NUMA if !FLATMEM
-	select PCI_MSI_ARCH_FALLBACKS if PCI_MSI
-	select ZONE_DMA32
-	select FUNCTION_ALIGNMENT_32B
-	default y
-	help
-	  The Itanium Processor Family is Intel's 64-bit successor to
-	  the 32-bit X86 line.  The IA-64 Linux project has a home
-	  page at <http://www.linuxia64.org/> and a mailing list at
-	  <linux-ia64@vger.kernel.org>.
-
-config 64BIT
-	bool
-	select ATA_NONSTANDARD if ATA
-	default y
-
-config MMU
-	bool
-	default y
-
-config STACKTRACE_SUPPORT
-	def_bool y
-
-config GENERIC_LOCKBREAK
-	def_bool n
-
-config GENERIC_CALIBRATE_DELAY
-	bool
-	default y
-
-config DMI
-	bool
-	default y
-	select DMI_SCAN_MACHINE_NON_EFI_FALLBACK
-
-config EFI
-	bool
-	select UCS2_STRING
-	default y
-
-config SCHED_OMIT_FRAME_POINTER
-	bool
-	default y
-
-config IA64_UNCACHED_ALLOCATOR
-	bool
-	select GENERIC_ALLOCATOR
-
-config ARCH_USES_PG_UNCACHED
-	def_bool y
-	depends on IA64_UNCACHED_ALLOCATOR
-
-config AUDIT_ARCH
-	bool
-	default y
-
-choice
-	prompt "Processor type"
-	default ITANIUM
-
-config ITANIUM
-	bool "Itanium"
-	help
-	  Select your IA-64 processor type.  The default is Itanium.
-	  This choice is safe for all IA-64 systems, but may not perform
-	  optimally on systems with, say, Itanium 2 or newer processors.
-
-config MCKINLEY
-	bool "Itanium 2"
-	help
-	  Select this to configure for an Itanium 2 (McKinley) processor.
-
-endchoice
-
-choice
-	prompt "Kernel page size"
-	default IA64_PAGE_SIZE_16KB
-
-config IA64_PAGE_SIZE_4KB
-	bool "4KB"
-	help
-	  This lets you select the page size of the kernel.  For best IA-64
-	  performance, a page size of 8KB or 16KB is recommended.  For best
-	  IA-32 compatibility, a page size of 4KB should be selected (the vast
-	  majority of IA-32 binaries work perfectly fine with a larger page
-	  size).  For Itanium 2 or newer systems, a page size of 64KB can also
-	  be selected.
-
-	  4KB                For best IA-32 compatibility
-	  8KB                For best IA-64 performance
-	  16KB               For best IA-64 performance
-	  64KB               Requires Itanium 2 or newer processor.
-
-	  If you don't know what to do, choose 16KB.
-
-config IA64_PAGE_SIZE_8KB
-	bool "8KB"
-
-config IA64_PAGE_SIZE_16KB
-	bool "16KB"
-
-config IA64_PAGE_SIZE_64KB
-	depends on !ITANIUM
-	bool "64KB"
-
-endchoice
-
-source "kernel/Kconfig.hz"
-
-config IA64_BRL_EMU
-	bool
-	depends on ITANIUM
-	default y
-
-# align cache-sensitive data to 128 bytes
-config IA64_L1_CACHE_SHIFT
-	int
-	default "7" if MCKINLEY
-	default "6" if ITANIUM
-
-config IA64_SGI_UV
-	bool "SGI-UV support"
-	help
-	  Selecting this option will add specific support for running on SGI
-	  UV based systems.  If you have an SGI UV system or are building a
-	  distro kernel, select this option.
-
-config IA64_HP_SBA_IOMMU
-	bool "HP SBA IOMMU support"
-	select DMA_OPS
-	default y
-	help
-	  Say Y here to add support for the SBA IOMMU found on HP zx1 and
-	  sx1000 systems.  If you're unsure, answer Y.
-
-config IA64_CYCLONE
-	bool "Cyclone (EXA) Time Source support"
-	help
-	  Say Y here to enable support for IBM EXA Cyclone time source.
-	  If you're unsure, answer N.
-
-config ARCH_FORCE_MAX_ORDER
-	int
-	default "16" if HUGETLB_PAGE
-	default "10"
-
-config SMP
-	bool "Symmetric multi-processing support"
-	help
-	  This enables support for systems with more than one CPU. If you have
-	  a system with only one CPU, say N.  If you have a system with more
-	  than one CPU, say Y.
-
-	  If you say N here, the kernel will run on single and multiprocessor
-	  systems, but will use only one CPU of a multiprocessor system.  If
-	  you say Y here, the kernel will run on many, but not all,
-	  single processor systems.  On a single processor system, the kernel
-	  will run faster if you say N here.
-
-	  See also the SMP-HOWTO available at
-	  <http://www.tldp.org/docs.html#howto>.
-
-	  If you don't know what to do here, say N.
-
-config NR_CPUS
-	int "Maximum number of CPUs (2-4096)"
-	range 2 4096
-	depends on SMP
-	default "4096"
-	help
-	  You should set this to the number of CPUs in your system, but
-	  keep in mind that a kernel compiled for, e.g., 2 CPUs will boot but
-	  only use 2 CPUs on a >2 CPU system.  Setting this to a value larger
-	  than 64 will cause the use of a CPU mask array, causing a small
-	  performance hit.
-
-config HOTPLUG_CPU
-	bool "Support for hot-pluggable CPUs"
-	depends on SMP
-	default n
-	help
-	  Say Y here to experiment with turning CPUs off and on.  CPUs
-	  can be controlled through /sys/devices/system/cpu/cpu#.
-	  Say N if you want to disable CPU hotplug.
-
-config SCHED_SMT
-	bool "SMT scheduler support"
-	depends on SMP
-	help
-	  Improves the CPU scheduler's decision making when dealing with
-	  Intel IA64 chips with MultiThreading at a cost of slightly increased
-	  overhead in some places. If unsure say N here.
-
-config PERMIT_BSP_REMOVE
-	bool "Support removal of Bootstrap Processor"
-	depends on HOTPLUG_CPU
-	default n
-	help
-	Say Y here if your platform SAL will support removal of BSP with HOTPLUG_CPU
-	support. 
-
-config FORCE_CPEI_RETARGET
-	bool "Force assumption that CPEI can be re-targeted"
-	depends on PERMIT_BSP_REMOVE
-	default n
-	help
-	Say Y if you need to force the assumption that CPEI can be re-targeted to
-	any cpu in the system. This hint is available via ACPI 3.0 specifications.
-	Tiger4 systems are capable of re-directing CPEI to any CPU other than BSP.
-	This option it useful to enable this feature on older BIOS's as well.
-	You can also enable this by using boot command line option force_cpei=1.
-
-config ARCH_SELECT_MEMORY_MODEL
-	def_bool y
-
-config ARCH_FLATMEM_ENABLE
-	def_bool y
-
-config ARCH_SPARSEMEM_ENABLE
-	def_bool y
-	select SPARSEMEM_VMEMMAP_ENABLE
-
-config ARCH_SPARSEMEM_DEFAULT
-	def_bool y
-	depends on ARCH_SPARSEMEM_ENABLE
-
-config NUMA
-	bool "NUMA support"
-	depends on !FLATMEM
-	select SMP
-	select USE_PERCPU_NUMA_NODE_ID
-	help
-	  Say Y to compile the kernel to support NUMA (Non-Uniform Memory
-	  Access).  This option is for configuring high-end multiprocessor
-	  server systems.  If in doubt, say N.
-
-config NODES_SHIFT
-	int "Max num nodes shift(3-10)"
-	range 3 10
-	default "10"
-	depends on NUMA
-	help
-	  This option specifies the maximum number of nodes in your SSI system.
-	  MAX_NUMNODES will be 2^(This value).
-	  If in doubt, use the default.
-
-config HAVE_ARCH_NODEDATA_EXTENSION
-	def_bool y
-	depends on NUMA
-
-config HAVE_MEMORYLESS_NODES
-	def_bool NUMA
-
-config ARCH_PROC_KCORE_TEXT
-	def_bool y
-	depends on PROC_KCORE
-
-config IA64_MCA_RECOVERY
-	bool "MCA recovery from errors other than TLB."
-
-config IA64_PALINFO
-	tristate "/proc/pal support"
-	help
-	  If you say Y here, you are able to get PAL (Processor Abstraction
-	  Layer) information in /proc/pal.  This contains useful information
-	  about the processors in your systems, such as cache and TLB sizes
-	  and the PAL firmware version in use.
-
-	  To use this option, you have to ensure that the "/proc file system
-	  support" (CONFIG_PROC_FS) is enabled, too.
-
-config IA64_MC_ERR_INJECT
-	tristate "MC error injection support"
-	help
-	  Adds support for MC error injection. If enabled, the kernel 
-	  will provide a sysfs interface for user applications to
-	  call MC error injection PAL procedures to inject various errors.
-	  This is a useful tool for MCA testing.
-
-	  If you're unsure, do not select this option.
-
-config IA64_ESI
-	bool "ESI (Extensible SAL Interface) support"
-	help
-	  If you say Y here, support is built into the kernel to
-	  make ESI calls.  ESI calls are used to support vendor-specific
-	  firmware extensions, such as the ability to inject memory-errors
-	  for test-purposes.  If you're unsure, say N.
-
-config IA64_HP_AML_NFW
-	bool "Support ACPI AML calls to native firmware"
-	help
-	  This driver installs a global ACPI Operation Region handler for
-	  region 0xA1.  AML methods can use this OpRegion to call arbitrary
-	  native firmware functions.  The driver installs the OpRegion
-	  handler if there is an HPQ5001 device or if the user supplies
-	  the "force" module parameter, e.g., with the "aml_nfw.force"
-	  kernel command line option.
-
-endmenu
-
-config ARCH_SUPPORTS_KEXEC
-	def_bool !SMP || HOTPLUG_CPU
-
-config ARCH_SUPPORTS_CRASH_DUMP
-	def_bool IA64_MCA_RECOVERY && (!SMP || HOTPLUG_CPU)
-
-menu "Power management and ACPI options"
-
-source "kernel/power/Kconfig"
-
-source "drivers/acpi/Kconfig"
-
-if PM
-menu "CPU Frequency scaling"
-source "drivers/cpufreq/Kconfig"
-endmenu
-endif
-
-endmenu
-
-config MSPEC
-	tristate "Memory special operations driver"
-	depends on IA64
-	select IA64_UNCACHED_ALLOCATOR
-	help
-	  If you have an ia64 and you want to enable memory special
-	  operations support (formerly known as fetchop), say Y here,
-	  otherwise say N.