summaryrefslogtreecommitdiffstats
path: root/drivers/xen/xen-acpi-cpuhotplug.c
blob: 3e62ee4b3b6641208e6833b639e25e5203f75ec9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
/*
 * 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;

	pr = acpi_driver_data(device);
	if (!pr) {
		pr_err(PREFIX "Cannot find driver data\n");
		return -EINVAL;
	}

	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 ((int)pr->id < 0)
		/* 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_dom0_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 ((int)pr->id < 0)
		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");