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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2012 Intel Corporation
4 * Author: Liu Jinsong <jinsong.liu@intel.com>
5 * Author: Jiang Yunhong <yunhong.jiang@intel.com>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/types.h>
14#include <linux/cpu.h>
15#include <linux/acpi.h>
16#include <linux/uaccess.h>
17#include <acpi/processor.h>
18#include <xen/acpi.h>
19#include <xen/interface/platform.h>
20#include <asm/xen/hypercall.h>
21
22#define PREFIX "ACPI:xen_cpu_hotplug:"
23
24#define INSTALL_NOTIFY_HANDLER 0
25#define UNINSTALL_NOTIFY_HANDLER 1
26
27static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
28
29/* --------------------------------------------------------------------------
30 Driver Interface
31-------------------------------------------------------------------------- */
32
33static int xen_acpi_processor_enable(struct acpi_device *device)
34{
35 acpi_status status = 0;
36 unsigned long long value;
37 union acpi_object object = { 0 };
38 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
39 struct acpi_processor *pr = acpi_driver_data(device);
40
41 if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
42 /* Declared with "Processor" statement; match ProcessorID */
43 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
44 if (ACPI_FAILURE(status)) {
45 pr_err(PREFIX "Evaluating processor object\n");
46 return -ENODEV;
47 }
48
49 pr->acpi_id = object.processor.proc_id;
50 } else {
51 /* Declared with "Device" statement; match _UID */
52 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
53 NULL, &value);
54 if (ACPI_FAILURE(status)) {
55 pr_err(PREFIX "Evaluating processor _UID\n");
56 return -ENODEV;
57 }
58
59 pr->acpi_id = value;
60 }
61
62 pr->id = xen_pcpu_id(pr->acpi_id);
63
64 if (invalid_logical_cpuid(pr->id))
65 /* This cpu is not presented at hypervisor, try to hotadd it */
66 if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
67 pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
68 pr->acpi_id);
69 return -ENODEV;
70 }
71
72 return 0;
73}
74
75static int xen_acpi_processor_add(struct acpi_device *device)
76{
77 int ret;
78 struct acpi_processor *pr;
79
80 if (!device)
81 return -EINVAL;
82
83 pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
84 if (!pr)
85 return -ENOMEM;
86
87 pr->handle = device->handle;
88 strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
89 strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
90 device->driver_data = pr;
91
92 ret = xen_acpi_processor_enable(device);
93 if (ret)
94 pr_err(PREFIX "Error when enabling Xen processor\n");
95
96 return ret;
97}
98
99static int xen_acpi_processor_remove(struct acpi_device *device)
100{
101 struct acpi_processor *pr;
102
103 if (!device)
104 return -EINVAL;
105
106 pr = acpi_driver_data(device);
107 if (!pr)
108 return -EINVAL;
109
110 kfree(pr);
111 return 0;
112}
113
114/*--------------------------------------------------------------
115 Acpi processor hotplug support
116--------------------------------------------------------------*/
117
118static int is_processor_present(acpi_handle handle)
119{
120 acpi_status status;
121 unsigned long long sta = 0;
122
123
124 status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
125
126 if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
127 return 1;
128
129 /*
130 * _STA is mandatory for a processor that supports hot plug
131 */
132 if (status == AE_NOT_FOUND)
133 pr_info(PREFIX "Processor does not support hot plug\n");
134 else
135 pr_info(PREFIX "Processor Device is not present");
136 return 0;
137}
138
139static int xen_apic_id(acpi_handle handle)
140{
141 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
142 union acpi_object *obj;
143 struct acpi_madt_local_apic *lapic;
144 int apic_id;
145
146 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
147 return -EINVAL;
148
149 if (!buffer.length || !buffer.pointer)
150 return -EINVAL;
151
152 obj = buffer.pointer;
153 if (obj->type != ACPI_TYPE_BUFFER ||
154 obj->buffer.length < sizeof(*lapic)) {
155 kfree(buffer.pointer);
156 return -EINVAL;
157 }
158
159 lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
160
161 if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
162 !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
163 kfree(buffer.pointer);
164 return -EINVAL;
165 }
166
167 apic_id = (uint32_t)lapic->id;
168 kfree(buffer.pointer);
169 buffer.length = ACPI_ALLOCATE_BUFFER;
170 buffer.pointer = NULL;
171
172 return apic_id;
173}
174
175static int xen_hotadd_cpu(struct acpi_processor *pr)
176{
177 int cpu_id, apic_id, pxm;
178 struct xen_platform_op op;
179
180 apic_id = xen_apic_id(pr->handle);
181 if (apic_id < 0) {
182 pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
183 pr->acpi_id);
184 return -ENODEV;
185 }
186
187 pxm = xen_acpi_get_pxm(pr->handle);
188 if (pxm < 0) {
189 pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
190 pr->acpi_id);
191 return pxm;
192 }
193
194 op.cmd = XENPF_cpu_hotadd;
195 op.u.cpu_add.apic_id = apic_id;
196 op.u.cpu_add.acpi_id = pr->acpi_id;
197 op.u.cpu_add.pxm = pxm;
198
199 cpu_id = HYPERVISOR_platform_op(&op);
200 if (cpu_id < 0)
201 pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
202 pr->acpi_id);
203
204 return cpu_id;
205}
206
207static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
208{
209 if (!is_processor_present(pr->handle))
210 return AE_ERROR;
211
212 pr->id = xen_hotadd_cpu(pr);
213 if (invalid_logical_cpuid(pr->id))
214 return AE_ERROR;
215
216 /*
217 * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
218 * interface after cpu hotadded.
219 */
220 xen_pcpu_hotplug_sync();
221
222 return AE_OK;
223}
224
225static int acpi_processor_device_remove(struct acpi_device *device)
226{
227 pr_debug(PREFIX "Xen does not support CPU hotremove\n");
228
229 return -ENOSYS;
230}
231
232static void acpi_processor_hotplug_notify(acpi_handle handle,
233 u32 event, void *data)
234{
235 struct acpi_processor *pr;
236 struct acpi_device *device = NULL;
237 u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
238 int result;
239
240 acpi_scan_lock_acquire();
241
242 switch (event) {
243 case ACPI_NOTIFY_BUS_CHECK:
244 case ACPI_NOTIFY_DEVICE_CHECK:
245 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
246 "Processor driver received %s event\n",
247 (event == ACPI_NOTIFY_BUS_CHECK) ?
248 "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
249
250 if (!is_processor_present(handle))
251 break;
252
253 acpi_bus_get_device(handle, &device);
254 if (acpi_device_enumerated(device))
255 break;
256
257 result = acpi_bus_scan(handle);
258 if (result) {
259 pr_err(PREFIX "Unable to add the device\n");
260 break;
261 }
262 device = NULL;
263 acpi_bus_get_device(handle, &device);
264 if (!acpi_device_enumerated(device)) {
265 pr_err(PREFIX "Missing device object\n");
266 break;
267 }
268 ost_code = ACPI_OST_SC_SUCCESS;
269 break;
270
271 case ACPI_NOTIFY_EJECT_REQUEST:
272 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
273 "received ACPI_NOTIFY_EJECT_REQUEST\n"));
274
275 if (acpi_bus_get_device(handle, &device)) {
276 pr_err(PREFIX "Device don't exist, dropping EJECT\n");
277 break;
278 }
279 pr = acpi_driver_data(device);
280 if (!pr) {
281 pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
282 break;
283 }
284
285 /*
286 * TBD: implement acpi_processor_device_remove if Xen support
287 * CPU hotremove in the future.
288 */
289 acpi_processor_device_remove(device);
290 break;
291
292 default:
293 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
294 "Unsupported event [0x%x]\n", event));
295
296 /* non-hotplug event; possibly handled by other handler */
297 goto out;
298 }
299
300 (void) acpi_evaluate_ost(handle, event, ost_code, NULL);
301
302out:
303 acpi_scan_lock_release();
304}
305
306static acpi_status is_processor_device(acpi_handle handle)
307{
308 struct acpi_device_info *info;
309 char *hid;
310 acpi_status status;
311
312 status = acpi_get_object_info(handle, &info);
313 if (ACPI_FAILURE(status))
314 return status;
315
316 if (info->type == ACPI_TYPE_PROCESSOR) {
317 kfree(info);
318 return AE_OK; /* found a processor object */
319 }
320
321 if (!(info->valid & ACPI_VALID_HID)) {
322 kfree(info);
323 return AE_ERROR;
324 }
325
326 hid = info->hardware_id.string;
327 if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
328 kfree(info);
329 return AE_ERROR;
330 }
331
332 kfree(info);
333 return AE_OK; /* found a processor device object */
334}
335
336static acpi_status
337processor_walk_namespace_cb(acpi_handle handle,
338 u32 lvl, void *context, void **rv)
339{
340 acpi_status status;
341 int *action = context;
342
343 status = is_processor_device(handle);
344 if (ACPI_FAILURE(status))
345 return AE_OK; /* not a processor; continue to walk */
346
347 switch (*action) {
348 case INSTALL_NOTIFY_HANDLER:
349 acpi_install_notify_handler(handle,
350 ACPI_SYSTEM_NOTIFY,
351 acpi_processor_hotplug_notify,
352 NULL);
353 break;
354 case UNINSTALL_NOTIFY_HANDLER:
355 acpi_remove_notify_handler(handle,
356 ACPI_SYSTEM_NOTIFY,
357 acpi_processor_hotplug_notify);
358 break;
359 default:
360 break;
361 }
362
363 /* found a processor; skip walking underneath */
364 return AE_CTRL_DEPTH;
365}
366
367static
368void acpi_processor_install_hotplug_notify(void)
369{
370 int action = INSTALL_NOTIFY_HANDLER;
371 acpi_walk_namespace(ACPI_TYPE_ANY,
372 ACPI_ROOT_OBJECT,
373 ACPI_UINT32_MAX,
374 processor_walk_namespace_cb, NULL, &action, NULL);
375}
376
377static
378void acpi_processor_uninstall_hotplug_notify(void)
379{
380 int action = UNINSTALL_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
387static const struct acpi_device_id processor_device_ids[] = {
388 {ACPI_PROCESSOR_OBJECT_HID, 0},
389 {ACPI_PROCESSOR_DEVICE_HID, 0},
390 {"", 0},
391};
392MODULE_DEVICE_TABLE(acpi, processor_device_ids);
393
394static struct acpi_driver xen_acpi_processor_driver = {
395 .name = "processor",
396 .class = ACPI_PROCESSOR_CLASS,
397 .ids = processor_device_ids,
398 .ops = {
399 .add = xen_acpi_processor_add,
400 .remove = xen_acpi_processor_remove,
401 },
402};
403
404static int __init xen_acpi_processor_init(void)
405{
406 int result = 0;
407
408 if (!xen_initial_domain())
409 return -ENODEV;
410
411 /* unregister the stub which only used to reserve driver space */
412 xen_stub_processor_exit();
413
414 result = acpi_bus_register_driver(&xen_acpi_processor_driver);
415 if (result < 0) {
416 xen_stub_processor_init();
417 return result;
418 }
419
420 acpi_processor_install_hotplug_notify();
421 return 0;
422}
423
424static void __exit xen_acpi_processor_exit(void)
425{
426 if (!xen_initial_domain())
427 return;
428
429 acpi_processor_uninstall_hotplug_notify();
430
431 acpi_bus_unregister_driver(&xen_acpi_processor_driver);
432
433 /*
434 * stub reserve space again to prevent any chance of native
435 * driver loading.
436 */
437 xen_stub_processor_init();
438 return;
439}
440
441module_init(xen_acpi_processor_init);
442module_exit(xen_acpi_processor_exit);
443ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
444MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
445MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
446MODULE_LICENSE("GPL");