Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/drivers/xen/xen-acpi-cpuhotplug.c

  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 
 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;
 50 
 51         pr = acpi_driver_data(device);
 52         if (!pr) {
 53                 pr_err(PREFIX "Cannot find driver data\n");
 54                 return -EINVAL;
 55         }
 56 
 57         if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
 58                 /* Declared with "Processor" statement; match ProcessorID */
 59                 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
 60                 if (ACPI_FAILURE(status)) {
 61                         pr_err(PREFIX "Evaluating processor object\n");
 62                         return -ENODEV;
 63                 }
 64 
 65                 pr->acpi_id = object.processor.proc_id;
 66         } else {
 67                 /* Declared with "Device" statement; match _UID */
 68                 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
 69                                                 NULL, &value);
 70                 if (ACPI_FAILURE(status)) {
 71                         pr_err(PREFIX "Evaluating processor _UID\n");
 72                         return -ENODEV;
 73                 }
 74 
 75                 pr->acpi_id = value;
 76         }
 77 
 78         pr->id = xen_pcpu_id(pr->acpi_id);
 79 
 80         if ((int)pr->id < 0)
 81                 /* This cpu is not presented at hypervisor, try to hotadd it */
 82                 if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
 83                         pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
 84                                         pr->acpi_id);
 85                         return -ENODEV;
 86                 }
 87 
 88         return 0;
 89 }
 90 
 91 static int xen_acpi_processor_add(struct acpi_device *device)
 92 {
 93         int ret;
 94         struct acpi_processor *pr;
 95 
 96         if (!device)
 97                 return -EINVAL;
 98 
 99         pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
100         if (!pr)
101                 return -ENOMEM;
102 
103         pr->handle = device->handle;
104         strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
105         strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
106         device->driver_data = pr;
107 
108         ret = xen_acpi_processor_enable(device);
109         if (ret)
110                 pr_err(PREFIX "Error when enabling Xen processor\n");
111 
112         return ret;
113 }
114 
115 static int xen_acpi_processor_remove(struct acpi_device *device)
116 {
117         struct acpi_processor *pr;
118 
119         if (!device)
120                 return -EINVAL;
121 
122         pr = acpi_driver_data(device);
123         if (!pr)
124                 return -EINVAL;
125 
126         kfree(pr);
127         return 0;
128 }
129 
130 /*--------------------------------------------------------------
131                 Acpi processor hotplug support
132 --------------------------------------------------------------*/
133 
134 static int is_processor_present(acpi_handle handle)
135 {
136         acpi_status status;
137         unsigned long long sta = 0;
138 
139 
140         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
141 
142         if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
143                 return 1;
144 
145         /*
146          * _STA is mandatory for a processor that supports hot plug
147          */
148         if (status == AE_NOT_FOUND)
149                 pr_info(PREFIX "Processor does not support hot plug\n");
150         else
151                 pr_info(PREFIX "Processor Device is not present");
152         return 0;
153 }
154 
155 static int xen_apic_id(acpi_handle handle)
156 {
157         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
158         union acpi_object *obj;
159         struct acpi_madt_local_apic *lapic;
160         int apic_id;
161 
162         if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
163                 return -EINVAL;
164 
165         if (!buffer.length || !buffer.pointer)
166                 return -EINVAL;
167 
168         obj = buffer.pointer;
169         if (obj->type != ACPI_TYPE_BUFFER ||
170             obj->buffer.length < sizeof(*lapic)) {
171                 kfree(buffer.pointer);
172                 return -EINVAL;
173         }
174 
175         lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
176 
177         if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
178             !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
179                 kfree(buffer.pointer);
180                 return -EINVAL;
181         }
182 
183         apic_id = (uint32_t)lapic->id;
184         kfree(buffer.pointer);
185         buffer.length = ACPI_ALLOCATE_BUFFER;
186         buffer.pointer = NULL;
187 
188         return apic_id;
189 }
190 
191 static int xen_hotadd_cpu(struct acpi_processor *pr)
192 {
193         int cpu_id, apic_id, pxm;
194         struct xen_platform_op op;
195 
196         apic_id = xen_apic_id(pr->handle);
197         if (apic_id < 0) {
198                 pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
199                                 pr->acpi_id);
200                 return -ENODEV;
201         }
202 
203         pxm = xen_acpi_get_pxm(pr->handle);
204         if (pxm < 0) {
205                 pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
206                                 pr->acpi_id);
207                 return pxm;
208         }
209 
210         op.cmd = XENPF_cpu_hotadd;
211         op.u.cpu_add.apic_id = apic_id;
212         op.u.cpu_add.acpi_id = pr->acpi_id;
213         op.u.cpu_add.pxm = pxm;
214 
215         cpu_id = HYPERVISOR_dom0_op(&op);
216         if (cpu_id < 0)
217                 pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
218                                 pr->acpi_id);
219 
220         return cpu_id;
221 }
222 
223 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
224 {
225         if (!is_processor_present(pr->handle))
226                 return AE_ERROR;
227 
228         pr->id = xen_hotadd_cpu(pr);
229         if ((int)pr->id < 0)
230                 return AE_ERROR;
231 
232         /*
233          * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
234          * interface after cpu hotadded.
235          */
236         xen_pcpu_hotplug_sync();
237 
238         return AE_OK;
239 }
240 
241 static int acpi_processor_device_remove(struct acpi_device *device)
242 {
243         pr_debug(PREFIX "Xen does not support CPU hotremove\n");
244 
245         return -ENOSYS;
246 }
247 
248 static void acpi_processor_hotplug_notify(acpi_handle handle,
249                                           u32 event, void *data)
250 {
251         struct acpi_processor *pr;
252         struct acpi_device *device = NULL;
253         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
254         int result;
255 
256         acpi_scan_lock_acquire();
257 
258         switch (event) {
259         case ACPI_NOTIFY_BUS_CHECK:
260         case ACPI_NOTIFY_DEVICE_CHECK:
261                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
262                         "Processor driver received %s event\n",
263                         (event == ACPI_NOTIFY_BUS_CHECK) ?
264                         "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
265 
266                 if (!is_processor_present(handle))
267                         break;
268 
269                 acpi_bus_get_device(handle, &device);
270                 if (acpi_device_enumerated(device))
271                         break;
272 
273                 result = acpi_bus_scan(handle);
274                 if (result) {
275                         pr_err(PREFIX "Unable to add the device\n");
276                         break;
277                 }
278                 device = NULL;
279                 acpi_bus_get_device(handle, &device);
280                 if (!acpi_device_enumerated(device)) {
281                         pr_err(PREFIX "Missing device object\n");
282                         break;
283                 }
284                 ost_code = ACPI_OST_SC_SUCCESS;
285                 break;
286 
287         case ACPI_NOTIFY_EJECT_REQUEST:
288                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
289                                   "received ACPI_NOTIFY_EJECT_REQUEST\n"));
290 
291                 if (acpi_bus_get_device(handle, &device)) {
292                         pr_err(PREFIX "Device don't exist, dropping EJECT\n");
293                         break;
294                 }
295                 pr = acpi_driver_data(device);
296                 if (!pr) {
297                         pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
298                         break;
299                 }
300 
301                 /*
302                  * TBD: implement acpi_processor_device_remove if Xen support
303                  * CPU hotremove in the future.
304                  */
305                 acpi_processor_device_remove(device);
306                 break;
307 
308         default:
309                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
310                                   "Unsupported event [0x%x]\n", event));
311 
312                 /* non-hotplug event; possibly handled by other handler */
313                 goto out;
314         }
315 
316         (void) acpi_evaluate_ost(handle, event, ost_code, NULL);
317 
318 out:
319         acpi_scan_lock_release();
320 }
321 
322 static acpi_status is_processor_device(acpi_handle handle)
323 {
324         struct acpi_device_info *info;
325         char *hid;
326         acpi_status status;
327 
328         status = acpi_get_object_info(handle, &info);
329         if (ACPI_FAILURE(status))
330                 return status;
331 
332         if (info->type == ACPI_TYPE_PROCESSOR) {
333                 kfree(info);
334                 return AE_OK;   /* found a processor object */
335         }
336 
337         if (!(info->valid & ACPI_VALID_HID)) {
338                 kfree(info);
339                 return AE_ERROR;
340         }
341 
342         hid = info->hardware_id.string;
343         if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
344                 kfree(info);
345                 return AE_ERROR;
346         }
347 
348         kfree(info);
349         return AE_OK;   /* found a processor device object */
350 }
351 
352 static acpi_status
353 processor_walk_namespace_cb(acpi_handle handle,
354                             u32 lvl, void *context, void **rv)
355 {
356         acpi_status status;
357         int *action = context;
358 
359         status = is_processor_device(handle);
360         if (ACPI_FAILURE(status))
361                 return AE_OK;   /* not a processor; continue to walk */
362 
363         switch (*action) {
364         case INSTALL_NOTIFY_HANDLER:
365                 acpi_install_notify_handler(handle,
366                                             ACPI_SYSTEM_NOTIFY,
367                                             acpi_processor_hotplug_notify,
368                                             NULL);
369                 break;
370         case UNINSTALL_NOTIFY_HANDLER:
371                 acpi_remove_notify_handler(handle,
372                                            ACPI_SYSTEM_NOTIFY,
373                                            acpi_processor_hotplug_notify);
374                 break;
375         default:
376                 break;
377         }
378 
379         /* found a processor; skip walking underneath */
380         return AE_CTRL_DEPTH;
381 }
382 
383 static
384 void acpi_processor_install_hotplug_notify(void)
385 {
386         int action = INSTALL_NOTIFY_HANDLER;
387         acpi_walk_namespace(ACPI_TYPE_ANY,
388                             ACPI_ROOT_OBJECT,
389                             ACPI_UINT32_MAX,
390                             processor_walk_namespace_cb, NULL, &action, NULL);
391 }
392 
393 static
394 void acpi_processor_uninstall_hotplug_notify(void)
395 {
396         int action = UNINSTALL_NOTIFY_HANDLER;
397         acpi_walk_namespace(ACPI_TYPE_ANY,
398                             ACPI_ROOT_OBJECT,
399                             ACPI_UINT32_MAX,
400                             processor_walk_namespace_cb, NULL, &action, NULL);
401 }
402 
403 static const struct acpi_device_id processor_device_ids[] = {
404         {ACPI_PROCESSOR_OBJECT_HID, 0},
405         {ACPI_PROCESSOR_DEVICE_HID, 0},
406         {"", 0},
407 };
408 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
409 
410 static struct acpi_driver xen_acpi_processor_driver = {
411         .name = "processor",
412         .class = ACPI_PROCESSOR_CLASS,
413         .ids = processor_device_ids,
414         .ops = {
415                 .add = xen_acpi_processor_add,
416                 .remove = xen_acpi_processor_remove,
417                 },
418 };
419 
420 static int __init xen_acpi_processor_init(void)
421 {
422         int result = 0;
423 
424         if (!xen_initial_domain())
425                 return -ENODEV;
426 
427         /* unregister the stub which only used to reserve driver space */
428         xen_stub_processor_exit();
429 
430         result = acpi_bus_register_driver(&xen_acpi_processor_driver);
431         if (result < 0) {
432                 xen_stub_processor_init();
433                 return result;
434         }
435 
436         acpi_processor_install_hotplug_notify();
437         return 0;
438 }
439 
440 static void __exit xen_acpi_processor_exit(void)
441 {
442         if (!xen_initial_domain())
443                 return;
444 
445         acpi_processor_uninstall_hotplug_notify();
446 
447         acpi_bus_unregister_driver(&xen_acpi_processor_driver);
448 
449         /*
450          * stub reserve space again to prevent any chance of native
451          * driver loading.
452          */
453         xen_stub_processor_init();
454         return;
455 }
456 
457 module_init(xen_acpi_processor_init);
458 module_exit(xen_acpi_processor_exit);
459 ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
460 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
461 MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
462 MODULE_LICENSE("GPL");
463 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us