2 * Copyright (C) 2012 Intel Corporation
3 * Author: Liu Jinsong <jinsong.liu@intel.com>
4 * Author: Jiang Yunhong <yunhong.jiang@intel.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or (at
9 * your option) any later version.
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
14 * NON INFRINGEMENT. See the GNU General Public License for more
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/types.h>
24 #include <linux/cpu.h>
25 #include <linux/acpi.h>
26 #include <linux/uaccess.h>
27 #include <acpi/acpi_bus.h>
28 #include <acpi/acpi_drivers.h>
29 #include <acpi/processor.h>
32 #include <xen/interface/platform.h>
33 #include <asm/xen/hypercall.h>
35 #define PREFIX "ACPI:xen_cpu_hotplug:"
37 #define INSTALL_NOTIFY_HANDLER 0
38 #define UNINSTALL_NOTIFY_HANDLER 1
40 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
42 /* --------------------------------------------------------------------------
44 -------------------------------------------------------------------------- */
46 static int xen_acpi_processor_enable(struct acpi_device *device)
48 acpi_status status = 0;
49 unsigned long long value;
50 union acpi_object object = { 0 };
51 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
52 struct acpi_processor *pr;
54 pr = acpi_driver_data(device);
56 pr_err(PREFIX "Cannot find driver data\n");
60 if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
61 /* Declared with "Processor" statement; match ProcessorID */
62 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
63 if (ACPI_FAILURE(status)) {
64 pr_err(PREFIX "Evaluating processor object\n");
68 pr->acpi_id = object.processor.proc_id;
70 /* Declared with "Device" statement; match _UID */
71 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
73 if (ACPI_FAILURE(status)) {
74 pr_err(PREFIX "Evaluating processor _UID\n");
81 pr->id = xen_pcpu_id(pr->acpi_id);
84 /* This cpu is not presented at hypervisor, try to hotadd it */
85 if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
86 pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
94 static int xen_acpi_processor_add(struct acpi_device *device)
97 struct acpi_processor *pr;
102 pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
106 pr->handle = device->handle;
107 strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
108 strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
109 device->driver_data = pr;
111 ret = xen_acpi_processor_enable(device);
113 pr_err(PREFIX "Error when enabling Xen processor\n");
118 static int xen_acpi_processor_remove(struct acpi_device *device)
120 struct acpi_processor *pr;
125 pr = acpi_driver_data(device);
133 /*--------------------------------------------------------------
134 Acpi processor hotplug support
135 --------------------------------------------------------------*/
137 static int is_processor_present(acpi_handle handle)
140 unsigned long long sta = 0;
143 status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
145 if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
149 * _STA is mandatory for a processor that supports hot plug
151 if (status == AE_NOT_FOUND)
152 pr_info(PREFIX "Processor does not support hot plug\n");
154 pr_info(PREFIX "Processor Device is not present");
158 static int xen_apic_id(acpi_handle handle)
160 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
161 union acpi_object *obj;
162 struct acpi_madt_local_apic *lapic;
165 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
168 if (!buffer.length || !buffer.pointer)
171 obj = buffer.pointer;
172 if (obj->type != ACPI_TYPE_BUFFER ||
173 obj->buffer.length < sizeof(*lapic)) {
174 kfree(buffer.pointer);
178 lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
180 if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
181 !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
182 kfree(buffer.pointer);
186 apic_id = (uint32_t)lapic->id;
187 kfree(buffer.pointer);
188 buffer.length = ACPI_ALLOCATE_BUFFER;
189 buffer.pointer = NULL;
194 static int xen_hotadd_cpu(struct acpi_processor *pr)
196 int cpu_id, apic_id, pxm;
197 struct xen_platform_op op;
199 apic_id = xen_apic_id(pr->handle);
201 pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
206 pxm = xen_acpi_get_pxm(pr->handle);
208 pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
213 op.cmd = XENPF_cpu_hotadd;
214 op.u.cpu_add.apic_id = apic_id;
215 op.u.cpu_add.acpi_id = pr->acpi_id;
216 op.u.cpu_add.pxm = pxm;
218 cpu_id = HYPERVISOR_dom0_op(&op);
220 pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
226 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
228 if (!is_processor_present(pr->handle))
231 pr->id = xen_hotadd_cpu(pr);
236 * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
237 * interface after cpu hotadded.
239 xen_pcpu_hotplug_sync();
244 static int acpi_processor_device_remove(struct acpi_device *device)
246 pr_debug(PREFIX "Xen does not support CPU hotremove\n");
251 static void acpi_processor_hotplug_notify(acpi_handle handle,
252 u32 event, void *data)
254 struct acpi_processor *pr;
255 struct acpi_device *device = NULL;
256 u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
259 acpi_scan_lock_acquire();
262 case ACPI_NOTIFY_BUS_CHECK:
263 case ACPI_NOTIFY_DEVICE_CHECK:
264 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
265 "Processor driver received %s event\n",
266 (event == ACPI_NOTIFY_BUS_CHECK) ?
267 "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
269 if (!is_processor_present(handle))
272 if (!acpi_bus_get_device(handle, &device))
275 result = acpi_bus_scan(handle);
277 pr_err(PREFIX "Unable to add the device\n");
280 result = acpi_bus_get_device(handle, &device);
282 pr_err(PREFIX "Missing device object\n");
285 ost_code = ACPI_OST_SC_SUCCESS;
288 case ACPI_NOTIFY_EJECT_REQUEST:
289 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
290 "received ACPI_NOTIFY_EJECT_REQUEST\n"));
292 if (acpi_bus_get_device(handle, &device)) {
293 pr_err(PREFIX "Device don't exist, dropping EJECT\n");
296 pr = acpi_driver_data(device);
298 pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
303 * TBD: implement acpi_processor_device_remove if Xen support
304 * CPU hotremove in the future.
306 acpi_processor_device_remove(device);
310 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
311 "Unsupported event [0x%x]\n", event));
313 /* non-hotplug event; possibly handled by other handler */
317 (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
320 acpi_scan_lock_release();
323 static acpi_status is_processor_device(acpi_handle handle)
325 struct acpi_device_info *info;
329 status = acpi_get_object_info(handle, &info);
330 if (ACPI_FAILURE(status))
333 if (info->type == ACPI_TYPE_PROCESSOR) {
335 return AE_OK; /* found a processor object */
338 if (!(info->valid & ACPI_VALID_HID)) {
343 hid = info->hardware_id.string;
344 if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
350 return AE_OK; /* found a processor device object */
354 processor_walk_namespace_cb(acpi_handle handle,
355 u32 lvl, void *context, void **rv)
358 int *action = context;
360 status = is_processor_device(handle);
361 if (ACPI_FAILURE(status))
362 return AE_OK; /* not a processor; continue to walk */
365 case INSTALL_NOTIFY_HANDLER:
366 acpi_install_notify_handler(handle,
368 acpi_processor_hotplug_notify,
371 case UNINSTALL_NOTIFY_HANDLER:
372 acpi_remove_notify_handler(handle,
374 acpi_processor_hotplug_notify);
380 /* found a processor; skip walking underneath */
381 return AE_CTRL_DEPTH;
385 void acpi_processor_install_hotplug_notify(void)
387 int action = INSTALL_NOTIFY_HANDLER;
388 acpi_walk_namespace(ACPI_TYPE_ANY,
391 processor_walk_namespace_cb, NULL, &action, NULL);
395 void acpi_processor_uninstall_hotplug_notify(void)
397 int action = UNINSTALL_NOTIFY_HANDLER;
398 acpi_walk_namespace(ACPI_TYPE_ANY,
401 processor_walk_namespace_cb, NULL, &action, NULL);
404 static const struct acpi_device_id processor_device_ids[] = {
405 {ACPI_PROCESSOR_OBJECT_HID, 0},
406 {ACPI_PROCESSOR_DEVICE_HID, 0},
409 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
411 static struct acpi_driver xen_acpi_processor_driver = {
413 .class = ACPI_PROCESSOR_CLASS,
414 .ids = processor_device_ids,
416 .add = xen_acpi_processor_add,
417 .remove = xen_acpi_processor_remove,
421 static int __init xen_acpi_processor_init(void)
425 if (!xen_initial_domain())
428 /* unregister the stub which only used to reserve driver space */
429 xen_stub_processor_exit();
431 result = acpi_bus_register_driver(&xen_acpi_processor_driver);
433 xen_stub_processor_init();
437 acpi_processor_install_hotplug_notify();
441 static void __exit xen_acpi_processor_exit(void)
443 if (!xen_initial_domain())
446 acpi_processor_uninstall_hotplug_notify();
448 acpi_bus_unregister_driver(&xen_acpi_processor_driver);
451 * stub reserve space again to prevent any chance of native
454 xen_stub_processor_init();
458 module_init(xen_acpi_processor_init);
459 module_exit(xen_acpi_processor_exit);
460 ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
461 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
462 MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
463 MODULE_LICENSE("GPL");