1 /*
2 * Copyright (C) 2012 Intel Corporation
3 * Author: Liu Jinsong <jinsong.liu@intel.com>
4 * Author: Jiang Yunhong <yunhong.jiang@intel.com>
5 *
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.
10 *
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
15 * details.
16 */
17
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
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/processor.h>
28 #include <xen/acpi.h>
29 #include <xen/interface/platform.h>
30 #include <asm/xen/hypercall.h>
31
32 #define PREFIX "ACPI:xen_cpu_hotplug:"
33
34 #define INSTALL_NOTIFY_HANDLER 0
35 #define UNINSTALL_NOTIFY_HANDLER 1
36
37 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
38
39 /* --------------------------------------------------------------------------
40 Driver Interface
41 -------------------------------------------------------------------------- */
42
xen_acpi_processor_enable(struct acpi_device * device)43 static int xen_acpi_processor_enable(struct acpi_device *device)
44 {
45 acpi_status status = 0;
46 unsigned long long value;
47 union acpi_object object = { 0 };
48 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
49 struct acpi_processor *pr = acpi_driver_data(device);
50
51 if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
52 /* Declared with "Processor" statement; match ProcessorID */
53 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
54 if (ACPI_FAILURE(status)) {
55 pr_err(PREFIX "Evaluating processor object\n");
56 return -ENODEV;
57 }
58
59 pr->acpi_id = object.processor.proc_id;
60 } else {
61 /* Declared with "Device" statement; match _UID */
62 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
63 NULL, &value);
64 if (ACPI_FAILURE(status)) {
65 pr_err(PREFIX "Evaluating processor _UID\n");
66 return -ENODEV;
67 }
68
69 pr->acpi_id = value;
70 }
71
72 pr->id = xen_pcpu_id(pr->acpi_id);
73
74 if (invalid_logical_cpuid(pr->id))
75 /* This cpu is not presented at hypervisor, try to hotadd it */
76 if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
77 pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
78 pr->acpi_id);
79 return -ENODEV;
80 }
81
82 return 0;
83 }
84
xen_acpi_processor_add(struct acpi_device * device)85 static int xen_acpi_processor_add(struct acpi_device *device)
86 {
87 int ret;
88 struct acpi_processor *pr;
89
90 if (!device)
91 return -EINVAL;
92
93 pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
94 if (!pr)
95 return -ENOMEM;
96
97 pr->handle = device->handle;
98 strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
99 strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
100 device->driver_data = pr;
101
102 ret = xen_acpi_processor_enable(device);
103 if (ret)
104 pr_err(PREFIX "Error when enabling Xen processor\n");
105
106 return ret;
107 }
108
xen_acpi_processor_remove(struct acpi_device * device)109 static int xen_acpi_processor_remove(struct acpi_device *device)
110 {
111 struct acpi_processor *pr;
112
113 if (!device)
114 return -EINVAL;
115
116 pr = acpi_driver_data(device);
117 if (!pr)
118 return -EINVAL;
119
120 kfree(pr);
121 return 0;
122 }
123
124 /*--------------------------------------------------------------
125 Acpi processor hotplug support
126 --------------------------------------------------------------*/
127
is_processor_present(acpi_handle handle)128 static int is_processor_present(acpi_handle handle)
129 {
130 acpi_status status;
131 unsigned long long sta = 0;
132
133
134 status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
135
136 if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
137 return 1;
138
139 /*
140 * _STA is mandatory for a processor that supports hot plug
141 */
142 if (status == AE_NOT_FOUND)
143 pr_info(PREFIX "Processor does not support hot plug\n");
144 else
145 pr_info(PREFIX "Processor Device is not present");
146 return 0;
147 }
148
xen_apic_id(acpi_handle handle)149 static int xen_apic_id(acpi_handle handle)
150 {
151 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
152 union acpi_object *obj;
153 struct acpi_madt_local_apic *lapic;
154 int apic_id;
155
156 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
157 return -EINVAL;
158
159 if (!buffer.length || !buffer.pointer)
160 return -EINVAL;
161
162 obj = buffer.pointer;
163 if (obj->type != ACPI_TYPE_BUFFER ||
164 obj->buffer.length < sizeof(*lapic)) {
165 kfree(buffer.pointer);
166 return -EINVAL;
167 }
168
169 lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
170
171 if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
172 !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
173 kfree(buffer.pointer);
174 return -EINVAL;
175 }
176
177 apic_id = (uint32_t)lapic->id;
178 kfree(buffer.pointer);
179 buffer.length = ACPI_ALLOCATE_BUFFER;
180 buffer.pointer = NULL;
181
182 return apic_id;
183 }
184
xen_hotadd_cpu(struct acpi_processor * pr)185 static int xen_hotadd_cpu(struct acpi_processor *pr)
186 {
187 int cpu_id, apic_id, pxm;
188 struct xen_platform_op op;
189
190 apic_id = xen_apic_id(pr->handle);
191 if (apic_id < 0) {
192 pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
193 pr->acpi_id);
194 return -ENODEV;
195 }
196
197 pxm = xen_acpi_get_pxm(pr->handle);
198 if (pxm < 0) {
199 pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
200 pr->acpi_id);
201 return pxm;
202 }
203
204 op.cmd = XENPF_cpu_hotadd;
205 op.u.cpu_add.apic_id = apic_id;
206 op.u.cpu_add.acpi_id = pr->acpi_id;
207 op.u.cpu_add.pxm = pxm;
208
209 cpu_id = HYPERVISOR_platform_op(&op);
210 if (cpu_id < 0)
211 pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
212 pr->acpi_id);
213
214 return cpu_id;
215 }
216
xen_acpi_cpu_hotadd(struct acpi_processor * pr)217 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
218 {
219 if (!is_processor_present(pr->handle))
220 return AE_ERROR;
221
222 pr->id = xen_hotadd_cpu(pr);
223 if (invalid_logical_cpuid(pr->id))
224 return AE_ERROR;
225
226 /*
227 * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
228 * interface after cpu hotadded.
229 */
230 xen_pcpu_hotplug_sync();
231
232 return AE_OK;
233 }
234
acpi_processor_device_remove(struct acpi_device * device)235 static int acpi_processor_device_remove(struct acpi_device *device)
236 {
237 pr_debug(PREFIX "Xen does not support CPU hotremove\n");
238
239 return -ENOSYS;
240 }
241
acpi_processor_hotplug_notify(acpi_handle handle,u32 event,void * data)242 static void acpi_processor_hotplug_notify(acpi_handle handle,
243 u32 event, void *data)
244 {
245 struct acpi_processor *pr;
246 struct acpi_device *device = NULL;
247 u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
248 int result;
249
250 acpi_scan_lock_acquire();
251
252 switch (event) {
253 case ACPI_NOTIFY_BUS_CHECK:
254 case ACPI_NOTIFY_DEVICE_CHECK:
255 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
256 "Processor driver received %s event\n",
257 (event == ACPI_NOTIFY_BUS_CHECK) ?
258 "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
259
260 if (!is_processor_present(handle))
261 break;
262
263 acpi_bus_get_device(handle, &device);
264 if (acpi_device_enumerated(device))
265 break;
266
267 result = acpi_bus_scan(handle);
268 if (result) {
269 pr_err(PREFIX "Unable to add the device\n");
270 break;
271 }
272 device = NULL;
273 acpi_bus_get_device(handle, &device);
274 if (!acpi_device_enumerated(device)) {
275 pr_err(PREFIX "Missing device object\n");
276 break;
277 }
278 ost_code = ACPI_OST_SC_SUCCESS;
279 break;
280
281 case ACPI_NOTIFY_EJECT_REQUEST:
282 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
283 "received ACPI_NOTIFY_EJECT_REQUEST\n"));
284
285 if (acpi_bus_get_device(handle, &device)) {
286 pr_err(PREFIX "Device don't exist, dropping EJECT\n");
287 break;
288 }
289 pr = acpi_driver_data(device);
290 if (!pr) {
291 pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
292 break;
293 }
294
295 /*
296 * TBD: implement acpi_processor_device_remove if Xen support
297 * CPU hotremove in the future.
298 */
299 acpi_processor_device_remove(device);
300 break;
301
302 default:
303 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
304 "Unsupported event [0x%x]\n", event));
305
306 /* non-hotplug event; possibly handled by other handler */
307 goto out;
308 }
309
310 (void) acpi_evaluate_ost(handle, event, ost_code, NULL);
311
312 out:
313 acpi_scan_lock_release();
314 }
315
is_processor_device(acpi_handle handle)316 static acpi_status is_processor_device(acpi_handle handle)
317 {
318 struct acpi_device_info *info;
319 char *hid;
320 acpi_status status;
321
322 status = acpi_get_object_info(handle, &info);
323 if (ACPI_FAILURE(status))
324 return status;
325
326 if (info->type == ACPI_TYPE_PROCESSOR) {
327 kfree(info);
328 return AE_OK; /* found a processor object */
329 }
330
331 if (!(info->valid & ACPI_VALID_HID)) {
332 kfree(info);
333 return AE_ERROR;
334 }
335
336 hid = info->hardware_id.string;
337 if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
338 kfree(info);
339 return AE_ERROR;
340 }
341
342 kfree(info);
343 return AE_OK; /* found a processor device object */
344 }
345
346 static acpi_status
processor_walk_namespace_cb(acpi_handle handle,u32 lvl,void * context,void ** rv)347 processor_walk_namespace_cb(acpi_handle handle,
348 u32 lvl, void *context, void **rv)
349 {
350 acpi_status status;
351 int *action = context;
352
353 status = is_processor_device(handle);
354 if (ACPI_FAILURE(status))
355 return AE_OK; /* not a processor; continue to walk */
356
357 switch (*action) {
358 case INSTALL_NOTIFY_HANDLER:
359 acpi_install_notify_handler(handle,
360 ACPI_SYSTEM_NOTIFY,
361 acpi_processor_hotplug_notify,
362 NULL);
363 break;
364 case UNINSTALL_NOTIFY_HANDLER:
365 acpi_remove_notify_handler(handle,
366 ACPI_SYSTEM_NOTIFY,
367 acpi_processor_hotplug_notify);
368 break;
369 default:
370 break;
371 }
372
373 /* found a processor; skip walking underneath */
374 return AE_CTRL_DEPTH;
375 }
376
377 static
acpi_processor_install_hotplug_notify(void)378 void acpi_processor_install_hotplug_notify(void)
379 {
380 int action = INSTALL_NOTIFY_HANDLER;
381 acpi_walk_namespace(ACPI_TYPE_ANY,
382 ACPI_ROOT_OBJECT,
383 ACPI_UINT32_MAX,
384 processor_walk_namespace_cb, NULL, &action, NULL);
385 }
386
387 static
acpi_processor_uninstall_hotplug_notify(void)388 void acpi_processor_uninstall_hotplug_notify(void)
389 {
390 int action = UNINSTALL_NOTIFY_HANDLER;
391 acpi_walk_namespace(ACPI_TYPE_ANY,
392 ACPI_ROOT_OBJECT,
393 ACPI_UINT32_MAX,
394 processor_walk_namespace_cb, NULL, &action, NULL);
395 }
396
397 static const struct acpi_device_id processor_device_ids[] = {
398 {ACPI_PROCESSOR_OBJECT_HID, 0},
399 {ACPI_PROCESSOR_DEVICE_HID, 0},
400 {"", 0},
401 };
402 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
403
404 static struct acpi_driver xen_acpi_processor_driver = {
405 .name = "processor",
406 .class = ACPI_PROCESSOR_CLASS,
407 .ids = processor_device_ids,
408 .ops = {
409 .add = xen_acpi_processor_add,
410 .remove = xen_acpi_processor_remove,
411 },
412 };
413
xen_acpi_processor_init(void)414 static int __init xen_acpi_processor_init(void)
415 {
416 int result = 0;
417
418 if (!xen_initial_domain())
419 return -ENODEV;
420
421 /* unregister the stub which only used to reserve driver space */
422 xen_stub_processor_exit();
423
424 result = acpi_bus_register_driver(&xen_acpi_processor_driver);
425 if (result < 0) {
426 xen_stub_processor_init();
427 return result;
428 }
429
430 acpi_processor_install_hotplug_notify();
431 return 0;
432 }
433
xen_acpi_processor_exit(void)434 static void __exit xen_acpi_processor_exit(void)
435 {
436 if (!xen_initial_domain())
437 return;
438
439 acpi_processor_uninstall_hotplug_notify();
440
441 acpi_bus_unregister_driver(&xen_acpi_processor_driver);
442
443 /*
444 * stub reserve space again to prevent any chance of native
445 * driver loading.
446 */
447 xen_stub_processor_init();
448 return;
449 }
450
451 module_init(xen_acpi_processor_init);
452 module_exit(xen_acpi_processor_exit);
453 ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
454 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
455 MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
456 MODULE_LICENSE("GPL");
457
