/* * Copyright (C) 2012 Intel Corporation * Author: Liu Jinsong <jinsong.liu@intel.com> * Author: Jiang Yunhong <yunhong.jiang@intel.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or * NON INFRINGEMENT. See the GNU General Public License for more * details. */ #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");