1 files changed, 446 insertions, 0 deletions
diff --git a/drivers/xen/xen-acpi-cpuhotplug.c b/drivers/xen/xen-acpi-cpuhotplug.c
new file mode 100644
index 000000000..00ab1ece0
--- /dev/null
+++ b/drivers/xen/xen-acpi-cpuhotplug.c
@@ -0,0 +1,446 @@
+// 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");