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The Itanium architecture is obsolete, and an informal survey [0] reveals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

4 files changed, 1 insertions, 141 deletions

diff --git a/drivers/misc/sgi-xp/xp.h b/drivers/misc/sgi-xp/xp.h
index f1336f43d3bd..3185711beb07 100644
--- a/drivers/misc/sgi-xp/xp.h
+++ b/drivers/misc/sgi-xp/xp.h
@@ -16,7 +16,7 @@
 
 #include <linux/mutex.h>
 
-#if defined CONFIG_X86_UV || defined CONFIG_IA64_SGI_UV
+#if defined CONFIG_X86_UV
 #include <asm/uv/uv.h>
 #endif
 
diff --git a/drivers/misc/sgi-xp/xp_uv.c b/drivers/misc/sgi-xp/xp_uv.c
index 19fc7076af27..3faa7eadf679 100644
--- a/drivers/misc/sgi-xp/xp_uv.c
+++ b/drivers/misc/sgi-xp/xp_uv.c
@@ -18,8 +18,6 @@
 #include <asm/uv/uv_hub.h>
 #if defined CONFIG_X86_64
 #include <asm/uv/bios.h>
-#elif defined CONFIG_IA64_SGI_UV
-#include <asm/sn/sn_sal.h>
 #endif
 #include "../sgi-gru/grukservices.h"
 #include "xp.h"
@@ -99,17 +97,6 @@ xp_expand_memprotect_uv(unsigned long phys_addr, unsigned long size)
 			"UV_MEMPROT_ALLOW_RW) failed, ret=%d\n", ret);
 		return xpBiosError;
 	}
-
-#elif defined CONFIG_IA64_SGI_UV
-	u64 nasid_array;
-
-	ret = sn_change_memprotect(phys_addr, size, SN_MEMPROT_ACCESS_CLASS_1,
-				   &nasid_array);
-	if (ret != 0) {
-		dev_err(xp, "sn_change_memprotect(,, "
-			"SN_MEMPROT_ACCESS_CLASS_1,) failed ret=%d\n", ret);
-		return xpSalError;
-	}
 #else
 	#error not a supported configuration
 #endif
@@ -129,17 +116,6 @@ xp_restrict_memprotect_uv(unsigned long phys_addr, unsigned long size)
 			"UV_MEMPROT_RESTRICT_ACCESS) failed, ret=%d\n", ret);
 		return xpBiosError;
 	}
-
-#elif defined CONFIG_IA64_SGI_UV
-	u64 nasid_array;
-
-	ret = sn_change_memprotect(phys_addr, size, SN_MEMPROT_ACCESS_CLASS_0,
-				   &nasid_array);
-	if (ret != 0) {
-		dev_err(xp, "sn_change_memprotect(,, "
-			"SN_MEMPROT_ACCESS_CLASS_0,) failed ret=%d\n", ret);
-		return xpSalError;
-	}
 #else
 	#error not a supported configuration
 #endif
diff --git a/drivers/misc/sgi-xp/xpc_main.c b/drivers/misc/sgi-xp/xpc_main.c
index 6da509d692bb..cc71395782b6 100644
--- a/drivers/misc/sgi-xp/xpc_main.c
+++ b/drivers/misc/sgi-xp/xpc_main.c
@@ -1155,36 +1155,6 @@ xpc_die_deactivate(void)
 static int
 xpc_system_die(struct notifier_block *nb, unsigned long event, void *_die_args)
 {
-#ifdef CONFIG_IA64		/* !!! temporary kludge */
-	switch (event) {
-	case DIE_MACHINE_RESTART:
-	case DIE_MACHINE_HALT:
-		xpc_die_deactivate();
-		break;
-
-	case DIE_KDEBUG_ENTER:
-		/* Should lack of heartbeat be ignored by other partitions? */
-		if (!xpc_kdebug_ignore)
-			break;
-
-		fallthrough;
-	case DIE_MCA_MONARCH_ENTER:
-	case DIE_INIT_MONARCH_ENTER:
-		xpc_arch_ops.offline_heartbeat();
-		break;
-
-	case DIE_KDEBUG_LEAVE:
-		/* Is lack of heartbeat being ignored by other partitions? */
-		if (!xpc_kdebug_ignore)
-			break;
-
-		fallthrough;
-	case DIE_MCA_MONARCH_LEAVE:
-	case DIE_INIT_MONARCH_LEAVE:
-		xpc_arch_ops.online_heartbeat();
-		break;
-	}
-#else
 	struct die_args *die_args = _die_args;
 
 	switch (event) {
@@ -1206,7 +1176,6 @@ xpc_system_die(struct notifier_block *nb, unsigned long event, void *_die_args)
 	default:
 		xpc_die_deactivate();
 	}
-#endif
 
 	return NOTIFY_DONE;
 }
diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c
index fff522d347e3..2f03a7080d96 100644
--- a/drivers/misc/sgi-xp/xpc_uv.c
+++ b/drivers/misc/sgi-xp/xpc_uv.c
@@ -24,34 +24,12 @@
 #include <linux/slab.h>
 #include <linux/numa.h>
 #include <asm/uv/uv_hub.h>
-#if defined CONFIG_X86_64
 #include <asm/uv/bios.h>
 #include <asm/uv/uv_irq.h>
-#elif defined CONFIG_IA64_SGI_UV
-#include <asm/sn/intr.h>
-#include <asm/sn/sn_sal.h>
-#endif
 #include "../sgi-gru/gru.h"
 #include "../sgi-gru/grukservices.h"
 #include "xpc.h"
 
-#if defined CONFIG_IA64_SGI_UV
-struct uv_IO_APIC_route_entry {
-	__u64	vector		:  8,
-		delivery_mode	:  3,
-		dest_mode	:  1,
-		delivery_status	:  1,
-		polarity	:  1,
-		__reserved_1	:  1,
-		trigger		:  1,
-		mask		:  1,
-		__reserved_2	: 15,
-		dest		: 32;
-};
-
-#define sn_partition_id 0
-#endif
-
 static struct xpc_heartbeat_uv *xpc_heartbeat_uv;
 
 #define XPC_ACTIVATE_MSG_SIZE_UV	(1 * GRU_CACHE_LINE_BYTES)
@@ -113,7 +91,6 @@ xpc_get_gru_mq_irq_uv(struct xpc_gru_mq_uv *mq, int cpu, char *irq_name)
 {
 	int mmr_pnode = uv_blade_to_pnode(mq->mmr_blade);
 
-#if defined CONFIG_X86_64
 	mq->irq = uv_setup_irq(irq_name, cpu, mq->mmr_blade, mq->mmr_offset,
 			UV_AFFINITY_CPU);
 	if (mq->irq < 0)
@@ -121,40 +98,13 @@ xpc_get_gru_mq_irq_uv(struct xpc_gru_mq_uv *mq, int cpu, char *irq_name)
 
 	mq->mmr_value = uv_read_global_mmr64(mmr_pnode, mq->mmr_offset);
 
-#elif defined CONFIG_IA64_SGI_UV
-	if (strcmp(irq_name, XPC_ACTIVATE_IRQ_NAME) == 0)
-		mq->irq = SGI_XPC_ACTIVATE;
-	else if (strcmp(irq_name, XPC_NOTIFY_IRQ_NAME) == 0)
-		mq->irq = SGI_XPC_NOTIFY;
-	else
-		return -EINVAL;
-
-	mq->mmr_value = (unsigned long)cpu_physical_id(cpu) << 32 | mq->irq;
-	uv_write_global_mmr64(mmr_pnode, mq->mmr_offset, mq->mmr_value);
-#else
-	#error not a supported configuration
-#endif
-
 	return 0;
 }
 
 static void
 xpc_release_gru_mq_irq_uv(struct xpc_gru_mq_uv *mq)
 {
-#if defined CONFIG_X86_64
 	uv_teardown_irq(mq->irq);
-
-#elif defined CONFIG_IA64_SGI_UV
-	int mmr_pnode;
-	unsigned long mmr_value;
-
-	mmr_pnode = uv_blade_to_pnode(mq->mmr_blade);
-	mmr_value = 1UL << 16;
-
-	uv_write_global_mmr64(mmr_pnode, mq->mmr_offset, mmr_value);
-#else
-	#error not a supported configuration
-#endif
 }
 
 static int
@@ -162,17 +112,6 @@ xpc_gru_mq_watchlist_alloc_uv(struct xpc_gru_mq_uv *mq)
 {
 	int ret;
 
-#if defined CONFIG_IA64_SGI_UV
-	int mmr_pnode = uv_blade_to_pnode(mq->mmr_blade);
-
-	ret = sn_mq_watchlist_alloc(mmr_pnode, (void *)uv_gpa(mq->address),
-				    mq->order, &mq->mmr_offset);
-	if (ret < 0) {
-		dev_err(xpc_part, "sn_mq_watchlist_alloc() failed, ret=%d\n",
-			ret);
-		return -EBUSY;
-	}
-#elif defined CONFIG_X86_64
 	ret = uv_bios_mq_watchlist_alloc(uv_gpa(mq->address),
 					 mq->order, &mq->mmr_offset);
 	if (ret < 0) {
@@ -180,9 +119,6 @@ xpc_gru_mq_watchlist_alloc_uv(struct xpc_gru_mq_uv *mq)
 			"ret=%d\n", ret);
 		return ret;
 	}
-#else
-	#error not a supported configuration
-#endif
 
 	mq->watchlist_num = ret;
 	return 0;
@@ -194,15 +130,8 @@ xpc_gru_mq_watchlist_free_uv(struct xpc_gru_mq_uv *mq)
 	int ret;
 	int mmr_pnode = uv_blade_to_pnode(mq->mmr_blade);
 
-#if defined CONFIG_X86_64
 	ret = uv_bios_mq_watchlist_free(mmr_pnode, mq->watchlist_num);
 	BUG_ON(ret != BIOS_STATUS_SUCCESS);
-#elif defined CONFIG_IA64_SGI_UV
-	ret = sn_mq_watchlist_free(mmr_pnode, mq->watchlist_num);
-	BUG_ON(ret != SALRET_OK);
-#else
-	#error not a supported configuration
-#endif
 }
 
 static struct xpc_gru_mq_uv *
@@ -786,7 +715,6 @@ xpc_get_partition_rsvd_page_pa_uv(void *buf, u64 *cookie, unsigned long *rp_pa,
 	s64 status;
 	enum xp_retval ret;
 
-#if defined CONFIG_X86_64
 	status = uv_bios_reserved_page_pa((u64)buf, cookie, (u64 *)rp_pa,
 					  (u64 *)len);
 	if (status == BIOS_STATUS_SUCCESS)
@@ -796,19 +724,6 @@ xpc_get_partition_rsvd_page_pa_uv(void *buf, u64 *cookie, unsigned long *rp_pa,
 	else
 		ret = xpBiosError;
 
-#elif defined CONFIG_IA64_SGI_UV
-	status = sn_partition_reserved_page_pa((u64)buf, cookie, rp_pa, len);
-	if (status == SALRET_OK)
-		ret = xpSuccess;
-	else if (status == SALRET_MORE_PASSES)
-		ret = xpNeedMoreInfo;
-	else
-		ret = xpSalError;
-
-#else
-	#error not a supported configuration
-#endif
-
 	return ret;
 }