xen: Remove support for PV ACPI cpu/memory hotplug

Commit 76fc253723ad ("xen/acpi-stub: Disable it b/c the acpi_processor_add
is no longer called.") declared as BROKEN support for Xen ACPI stub (which
is required for xen-acpi-{cpu|memory}-hotplug) and suggested that this
is temporary and will be soon fixed. This was in March 2013.

Further, commit cfafae940381 ("xen: rename dom0_op to platform_op")
renamed an interface used by memory hotplug code without updating that
code (as it was BROKEN and therefore not compiled). This was
in November 2015 and has gone unnoticed for over 5 year.

It is now clear that this code is of no interest to anyone and therefore
should be removed.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/1618336344-3162-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Juergen Gross <jgross@suse.com>

1 files changed, 0 insertions, 446 deletions

diff --git a/drivers/xen/xen-acpi-cpuhotplug.c b/drivers/xen/xen-acpi-cpuhotplug.c
deleted file mode 100644
index 00ab1ece02e5..000000000000
--- a/drivers/xen/xen-acpi-cpuhotplug.c
+++ /dev/null
@@ -1,446 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Copyright (C) 2012 Intel Corporation
- *    Author: Liu Jinsong <jinsong.liu@intel.com>
- *    Author: Jiang Yunhong <yunhong.jiang@intel.com>
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/types.h>
-#include <linux/cpu.h>
-#include <linux/acpi.h>
-#include <linux/uaccess.h>
-#include <acpi/processor.h>
-#include <xen/acpi.h>
-#include <xen/interface/platform.h>
-#include <asm/xen/hypercall.h>
-
-#define PREFIX "ACPI:xen_cpu_hotplug:"
-
-#define INSTALL_NOTIFY_HANDLER		0
-#define UNINSTALL_NOTIFY_HANDLER	1
-
-static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
-
-/* --------------------------------------------------------------------------
-				Driver Interface
--------------------------------------------------------------------------- */
-
-static int xen_acpi_processor_enable(struct acpi_device *device)
-{
-	acpi_status status = 0;
-	unsigned long long value;
-	union acpi_object object = { 0 };
-	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
-	struct acpi_processor *pr = acpi_driver_data(device);
-
-	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
-		/* Declared with "Processor" statement; match ProcessorID */
-		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
-		if (ACPI_FAILURE(status)) {
-			pr_err(PREFIX "Evaluating processor object\n");
-			return -ENODEV;
-		}
-
-		pr->acpi_id = object.processor.proc_id;
-	} else {
-		/* Declared with "Device" statement; match _UID */
-		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
-						NULL, &value);
-		if (ACPI_FAILURE(status)) {
-			pr_err(PREFIX "Evaluating processor _UID\n");
-			return -ENODEV;
-		}
-
-		pr->acpi_id = value;
-	}
-
-	pr->id = xen_pcpu_id(pr->acpi_id);
-
-	if (invalid_logical_cpuid(pr->id))
-		/* This cpu is not presented at hypervisor, try to hotadd it */
-		if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
-			pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
-					pr->acpi_id);
-			return -ENODEV;
-		}
-
-	return 0;
-}
-
-static int xen_acpi_processor_add(struct acpi_device *device)
-{
-	int ret;
-	struct acpi_processor *pr;
-
-	if (!device)
-		return -EINVAL;
-
-	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
-	if (!pr)
-		return -ENOMEM;
-
-	pr->handle = device->handle;
-	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
-	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
-	device->driver_data = pr;
-
-	ret = xen_acpi_processor_enable(device);
-	if (ret)
-		pr_err(PREFIX "Error when enabling Xen processor\n");
-
-	return ret;
-}
-
-static int xen_acpi_processor_remove(struct acpi_device *device)
-{
-	struct acpi_processor *pr;
-
-	if (!device)
-		return -EINVAL;
-
-	pr = acpi_driver_data(device);
-	if (!pr)
-		return -EINVAL;
-
-	kfree(pr);
-	return 0;
-}
-
-/*--------------------------------------------------------------
-		Acpi processor hotplug support
---------------------------------------------------------------*/
-
-static int is_processor_present(acpi_handle handle)
-{
-	acpi_status status;
-	unsigned long long sta = 0;
-
-
-	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
-
-	if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
-		return 1;
-
-	/*
-	 * _STA is mandatory for a processor that supports hot plug
-	 */
-	if (status == AE_NOT_FOUND)
-		pr_info(PREFIX "Processor does not support hot plug\n");
-	else
-		pr_info(PREFIX "Processor Device is not present");
-	return 0;
-}
-
-static int xen_apic_id(acpi_handle handle)
-{
-	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-	union acpi_object *obj;
-	struct acpi_madt_local_apic *lapic;
-	int apic_id;
-
-	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
-		return -EINVAL;
-
-	if (!buffer.length || !buffer.pointer)
-		return -EINVAL;
-
-	obj = buffer.pointer;
-	if (obj->type != ACPI_TYPE_BUFFER ||
-	    obj->buffer.length < sizeof(*lapic)) {
-		kfree(buffer.pointer);
-		return -EINVAL;
-	}
-
-	lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
-
-	if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
-	    !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
-		kfree(buffer.pointer);
-		return -EINVAL;
-	}
-
-	apic_id = (uint32_t)lapic->id;
-	kfree(buffer.pointer);
-	buffer.length = ACPI_ALLOCATE_BUFFER;
-	buffer.pointer = NULL;
-
-	return apic_id;
-}
-
-static int xen_hotadd_cpu(struct acpi_processor *pr)
-{
-	int cpu_id, apic_id, pxm;
-	struct xen_platform_op op;
-
-	apic_id = xen_apic_id(pr->handle);
-	if (apic_id < 0) {
-		pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
-				pr->acpi_id);
-		return -ENODEV;
-	}
-
-	pxm = xen_acpi_get_pxm(pr->handle);
-	if (pxm < 0) {
-		pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
-				pr->acpi_id);
-		return pxm;
-	}
-
-	op.cmd = XENPF_cpu_hotadd;
-	op.u.cpu_add.apic_id = apic_id;
-	op.u.cpu_add.acpi_id = pr->acpi_id;
-	op.u.cpu_add.pxm = pxm;
-
-	cpu_id = HYPERVISOR_platform_op(&op);
-	if (cpu_id < 0)
-		pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
-				pr->acpi_id);
-
-	return cpu_id;
-}
-
-static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
-{
-	if (!is_processor_present(pr->handle))
-		return AE_ERROR;
-
-	pr->id = xen_hotadd_cpu(pr);
-	if (invalid_logical_cpuid(pr->id))
-		return AE_ERROR;
-
-	/*
-	 * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
-	 * interface after cpu hotadded.
-	 */
-	xen_pcpu_hotplug_sync();
-
-	return AE_OK;
-}
-
-static int acpi_processor_device_remove(struct acpi_device *device)
-{
-	pr_debug(PREFIX "Xen does not support CPU hotremove\n");
-
-	return -ENOSYS;
-}
-
-static void acpi_processor_hotplug_notify(acpi_handle handle,
-					  u32 event, void *data)
-{
-	struct acpi_processor *pr;
-	struct acpi_device *device = NULL;
-	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
-	int result;
-
-	acpi_scan_lock_acquire();
-
-	switch (event) {
-	case ACPI_NOTIFY_BUS_CHECK:
-	case ACPI_NOTIFY_DEVICE_CHECK:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-			"Processor driver received %s event\n",
-			(event == ACPI_NOTIFY_BUS_CHECK) ?
-			"ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
-
-		if (!is_processor_present(handle))
-			break;
-
-		acpi_bus_get_device(handle, &device);
-		if (acpi_device_enumerated(device))
-			break;
-
-		result = acpi_bus_scan(handle);
-		if (result) {
-			pr_err(PREFIX "Unable to add the device\n");
-			break;
-		}
-		device = NULL;
-		acpi_bus_get_device(handle, &device);
-		if (!acpi_device_enumerated(device)) {
-			pr_err(PREFIX "Missing device object\n");
-			break;
-		}
-		ost_code = ACPI_OST_SC_SUCCESS;
-		break;
-
-	case ACPI_NOTIFY_EJECT_REQUEST:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "received ACPI_NOTIFY_EJECT_REQUEST\n"));
-
-		if (acpi_bus_get_device(handle, &device)) {
-			pr_err(PREFIX "Device don't exist, dropping EJECT\n");
-			break;
-		}
-		pr = acpi_driver_data(device);
-		if (!pr) {
-			pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
-			break;
-		}
-
-		/*
-		 * TBD: implement acpi_processor_device_remove if Xen support
-		 * CPU hotremove in the future.
-		 */
-		acpi_processor_device_remove(device);
-		break;
-
-	default:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "Unsupported event [0x%x]\n", event));
-
-		/* non-hotplug event; possibly handled by other handler */
-		goto out;
-	}
-
-	(void) acpi_evaluate_ost(handle, event, ost_code, NULL);
-
-out:
-	acpi_scan_lock_release();
-}
-
-static acpi_status is_processor_device(acpi_handle handle)
-{
-	struct acpi_device_info *info;
-	char *hid;
-	acpi_status status;
-
-	status = acpi_get_object_info(handle, &info);
-	if (ACPI_FAILURE(status))
-		return status;
-
-	if (info->type == ACPI_TYPE_PROCESSOR) {
-		kfree(info);
-		return AE_OK;	/* found a processor object */
-	}
-
-	if (!(info->valid & ACPI_VALID_HID)) {
-		kfree(info);
-		return AE_ERROR;
-	}
-
-	hid = info->hardware_id.string;
-	if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
-		kfree(info);
-		return AE_ERROR;
-	}
-
-	kfree(info);
-	return AE_OK;	/* found a processor device object */
-}
-
-static acpi_status
-processor_walk_namespace_cb(acpi_handle handle,
-			    u32 lvl, void *context, void **rv)
-{
-	acpi_status status;
-	int *action = context;
-
-	status = is_processor_device(handle);
-	if (ACPI_FAILURE(status))
-		return AE_OK;	/* not a processor; continue to walk */
-
-	switch (*action) {
-	case INSTALL_NOTIFY_HANDLER:
-		acpi_install_notify_handler(handle,
-					    ACPI_SYSTEM_NOTIFY,
-					    acpi_processor_hotplug_notify,
-					    NULL);
-		break;
-	case UNINSTALL_NOTIFY_HANDLER:
-		acpi_remove_notify_handler(handle,
-					   ACPI_SYSTEM_NOTIFY,
-					   acpi_processor_hotplug_notify);
-		break;
-	default:
-		break;
-	}
-
-	/* found a processor; skip walking underneath */
-	return AE_CTRL_DEPTH;
-}
-
-static
-void acpi_processor_install_hotplug_notify(void)
-{
-	int action = INSTALL_NOTIFY_HANDLER;
-	acpi_walk_namespace(ACPI_TYPE_ANY,
-			    ACPI_ROOT_OBJECT,
-			    ACPI_UINT32_MAX,
-			    processor_walk_namespace_cb, NULL, &action, NULL);
-}
-
-static
-void acpi_processor_uninstall_hotplug_notify(void)
-{
-	int action = UNINSTALL_NOTIFY_HANDLER;
-	acpi_walk_namespace(ACPI_TYPE_ANY,
-			    ACPI_ROOT_OBJECT,
-			    ACPI_UINT32_MAX,
-			    processor_walk_namespace_cb, NULL, &action, NULL);
-}
-
-static const struct acpi_device_id processor_device_ids[] = {
-	{ACPI_PROCESSOR_OBJECT_HID, 0},
-	{ACPI_PROCESSOR_DEVICE_HID, 0},
-	{"", 0},
-};
-MODULE_DEVICE_TABLE(acpi, processor_device_ids);
-
-static struct acpi_driver xen_acpi_processor_driver = {
-	.name = "processor",
-	.class = ACPI_PROCESSOR_CLASS,
-	.ids = processor_device_ids,
-	.ops = {
-		.add = xen_acpi_processor_add,
-		.remove = xen_acpi_processor_remove,
-		},
-};
-
-static int __init xen_acpi_processor_init(void)
-{
-	int result = 0;
-
-	if (!xen_initial_domain())
-		return -ENODEV;
-
-	/* unregister the stub which only used to reserve driver space */
-	xen_stub_processor_exit();
-
-	result = acpi_bus_register_driver(&xen_acpi_processor_driver);
-	if (result < 0) {
-		xen_stub_processor_init();
-		return result;
-	}
-
-	acpi_processor_install_hotplug_notify();
-	return 0;
-}
-
-static void __exit xen_acpi_processor_exit(void)
-{
-	if (!xen_initial_domain())
-		return;
-
-	acpi_processor_uninstall_hotplug_notify();
-
-	acpi_bus_unregister_driver(&xen_acpi_processor_driver);
-
-	/*
-	 * stub reserve space again to prevent any chance of native
-	 * driver loading.
-	 */
-	xen_stub_processor_init();
-	return;
-}
-
-module_init(xen_acpi_processor_init);
-module_exit(xen_acpi_processor_exit);
-ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
-MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
-MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
-MODULE_LICENSE("GPL");