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Linux/drivers/xen/xen-acpi-memhotplug.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/acpi.h>
 25 #include <xen/acpi.h>
 26 #include <xen/interface/platform.h>
 27 #include <asm/xen/hypercall.h>
 28 
 29 #define PREFIX "ACPI:xen_memory_hotplug:"
 30 
 31 struct acpi_memory_info {
 32         struct list_head list;
 33         u64 start_addr;         /* Memory Range start physical addr */
 34         u64 length;             /* Memory Range length */
 35         unsigned short caching; /* memory cache attribute */
 36         unsigned short write_protect;   /* memory read/write attribute */
 37                                 /* copied from buffer getting from _CRS */
 38         unsigned int enabled:1;
 39 };
 40 
 41 struct acpi_memory_device {
 42         struct acpi_device *device;
 43         struct list_head res_list;
 44 };
 45 
 46 static bool acpi_hotmem_initialized __read_mostly;
 47 
 48 static int xen_hotadd_memory(int pxm, struct acpi_memory_info *info)
 49 {
 50         int rc;
 51         struct xen_platform_op op;
 52 
 53         op.cmd = XENPF_mem_hotadd;
 54         op.u.mem_add.spfn = info->start_addr >> PAGE_SHIFT;
 55         op.u.mem_add.epfn = (info->start_addr + info->length) >> PAGE_SHIFT;
 56         op.u.mem_add.pxm = pxm;
 57 
 58         rc = HYPERVISOR_dom0_op(&op);
 59         if (rc)
 60                 pr_err(PREFIX "Xen Hotplug Memory Add failed on "
 61                         "0x%lx -> 0x%lx, _PXM: %d, error: %d\n",
 62                         (unsigned long)info->start_addr,
 63                         (unsigned long)(info->start_addr + info->length),
 64                         pxm, rc);
 65 
 66         return rc;
 67 }
 68 
 69 static int xen_acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 70 {
 71         int pxm, result;
 72         int num_enabled = 0;
 73         struct acpi_memory_info *info;
 74 
 75         if (!mem_device)
 76                 return -EINVAL;
 77 
 78         pxm = xen_acpi_get_pxm(mem_device->device->handle);
 79         if (pxm < 0)
 80                 return pxm;
 81 
 82         list_for_each_entry(info, &mem_device->res_list, list) {
 83                 if (info->enabled) { /* just sanity check...*/
 84                         num_enabled++;
 85                         continue;
 86                 }
 87 
 88                 if (!info->length)
 89                         continue;
 90 
 91                 result = xen_hotadd_memory(pxm, info);
 92                 if (result)
 93                         continue;
 94                 info->enabled = 1;
 95                 num_enabled++;
 96         }
 97 
 98         if (!num_enabled)
 99                 return -ENODEV;
100 
101         return 0;
102 }
103 
104 static acpi_status
105 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
106 {
107         struct acpi_memory_device *mem_device = context;
108         struct acpi_resource_address64 address64;
109         struct acpi_memory_info *info, *new;
110         acpi_status status;
111 
112         status = acpi_resource_to_address64(resource, &address64);
113         if (ACPI_FAILURE(status) ||
114             (address64.resource_type != ACPI_MEMORY_RANGE))
115                 return AE_OK;
116 
117         list_for_each_entry(info, &mem_device->res_list, list) {
118                 if ((info->caching == address64.info.mem.caching) &&
119                     (info->write_protect == address64.info.mem.write_protect) &&
120                     (info->start_addr + info->length == address64.minimum)) {
121                         info->length += address64.address_length;
122                         return AE_OK;
123                 }
124         }
125 
126         new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
127         if (!new)
128                 return AE_ERROR;
129 
130         INIT_LIST_HEAD(&new->list);
131         new->caching = address64.info.mem.caching;
132         new->write_protect = address64.info.mem.write_protect;
133         new->start_addr = address64.minimum;
134         new->length = address64.address_length;
135         list_add_tail(&new->list, &mem_device->res_list);
136 
137         return AE_OK;
138 }
139 
140 static int
141 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
142 {
143         acpi_status status;
144         struct acpi_memory_info *info, *n;
145 
146         if (!list_empty(&mem_device->res_list))
147                 return 0;
148 
149         status = acpi_walk_resources(mem_device->device->handle,
150                 METHOD_NAME__CRS, acpi_memory_get_resource, mem_device);
151 
152         if (ACPI_FAILURE(status)) {
153                 list_for_each_entry_safe(info, n, &mem_device->res_list, list)
154                         kfree(info);
155                 INIT_LIST_HEAD(&mem_device->res_list);
156                 return -EINVAL;
157         }
158 
159         return 0;
160 }
161 
162 static int acpi_memory_get_device(acpi_handle handle,
163                                   struct acpi_memory_device **mem_device)
164 {
165         struct acpi_device *device = NULL;
166         int result = 0;
167 
168         acpi_scan_lock_acquire();
169 
170         acpi_bus_get_device(handle, &device);
171         if (acpi_device_enumerated(device))
172                 goto end;
173 
174         /*
175          * Now add the notified device.  This creates the acpi_device
176          * and invokes .add function
177          */
178         result = acpi_bus_scan(handle);
179         if (result) {
180                 pr_warn(PREFIX "ACPI namespace scan failed\n");
181                 result = -EINVAL;
182                 goto out;
183         }
184         device = NULL;
185         acpi_bus_get_device(handle, &device);
186         if (!acpi_device_enumerated(device)) {
187                 pr_warn(PREFIX "Missing device object\n");
188                 result = -EINVAL;
189                 goto out;
190         }
191 
192 end:
193         *mem_device = acpi_driver_data(device);
194         if (!(*mem_device)) {
195                 pr_err(PREFIX "driver data not found\n");
196                 result = -ENODEV;
197                 goto out;
198         }
199 
200 out:
201         acpi_scan_lock_release();
202         return result;
203 }
204 
205 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
206 {
207         unsigned long long current_status;
208 
209         /* Get device present/absent information from the _STA */
210         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
211                                 "_STA", NULL, &current_status)))
212                 return -ENODEV;
213         /*
214          * Check for device status. Device should be
215          * present/enabled/functioning.
216          */
217         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
218               && (current_status & ACPI_STA_DEVICE_ENABLED)
219               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
220                 return -ENODEV;
221 
222         return 0;
223 }
224 
225 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
226 {
227         pr_debug(PREFIX "Xen does not support memory hotremove\n");
228 
229         return -ENOSYS;
230 }
231 
232 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
233 {
234         struct acpi_memory_device *mem_device;
235         struct acpi_device *device;
236         u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
237 
238         switch (event) {
239         case ACPI_NOTIFY_BUS_CHECK:
240                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
241                         "\nReceived BUS CHECK notification for device\n"));
242                 /* Fall Through */
243         case ACPI_NOTIFY_DEVICE_CHECK:
244                 if (event == ACPI_NOTIFY_DEVICE_CHECK)
245                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
246                         "\nReceived DEVICE CHECK notification for device\n"));
247 
248                 if (acpi_memory_get_device(handle, &mem_device)) {
249                         pr_err(PREFIX "Cannot find driver data\n");
250                         break;
251                 }
252 
253                 ost_code = ACPI_OST_SC_SUCCESS;
254                 break;
255 
256         case ACPI_NOTIFY_EJECT_REQUEST:
257                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
258                         "\nReceived EJECT REQUEST notification for device\n"));
259 
260                 acpi_scan_lock_acquire();
261                 if (acpi_bus_get_device(handle, &device)) {
262                         acpi_scan_lock_release();
263                         pr_err(PREFIX "Device doesn't exist\n");
264                         break;
265                 }
266                 mem_device = acpi_driver_data(device);
267                 if (!mem_device) {
268                         acpi_scan_lock_release();
269                         pr_err(PREFIX "Driver Data is NULL\n");
270                         break;
271                 }
272 
273                 /*
274                  * TBD: implement acpi_memory_disable_device and invoke
275                  * acpi_bus_remove if Xen support hotremove in the future
276                  */
277                 acpi_memory_disable_device(mem_device);
278                 acpi_scan_lock_release();
279                 break;
280 
281         default:
282                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
283                                   "Unsupported event [0x%x]\n", event));
284                 /* non-hotplug event; possibly handled by other handler */
285                 return;
286         }
287 
288         (void) acpi_evaluate_ost(handle, event, ost_code, NULL);
289         return;
290 }
291 
292 static int xen_acpi_memory_device_add(struct acpi_device *device)
293 {
294         int result;
295         struct acpi_memory_device *mem_device = NULL;
296 
297 
298         if (!device)
299                 return -EINVAL;
300 
301         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
302         if (!mem_device)
303                 return -ENOMEM;
304 
305         INIT_LIST_HEAD(&mem_device->res_list);
306         mem_device->device = device;
307         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
308         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
309         device->driver_data = mem_device;
310 
311         /* Get the range from the _CRS */
312         result = acpi_memory_get_device_resources(mem_device);
313         if (result) {
314                 kfree(mem_device);
315                 return result;
316         }
317 
318         /*
319          * For booting existed memory devices, early boot code has recognized
320          * memory area by EFI/E820. If DSDT shows these memory devices on boot,
321          * hotplug is not necessary for them.
322          * For hot-added memory devices during runtime, it need hypercall to
323          * Xen hypervisor to add memory.
324          */
325         if (!acpi_hotmem_initialized)
326                 return 0;
327 
328         if (!acpi_memory_check_device(mem_device))
329                 result = xen_acpi_memory_enable_device(mem_device);
330 
331         return result;
332 }
333 
334 static int xen_acpi_memory_device_remove(struct acpi_device *device)
335 {
336         struct acpi_memory_device *mem_device = NULL;
337 
338         if (!device || !acpi_driver_data(device))
339                 return -EINVAL;
340 
341         mem_device = acpi_driver_data(device);
342         kfree(mem_device);
343 
344         return 0;
345 }
346 
347 /*
348  * Helper function to check for memory device
349  */
350 static acpi_status is_memory_device(acpi_handle handle)
351 {
352         char *hardware_id;
353         acpi_status status;
354         struct acpi_device_info *info;
355 
356         status = acpi_get_object_info(handle, &info);
357         if (ACPI_FAILURE(status))
358                 return status;
359 
360         if (!(info->valid & ACPI_VALID_HID)) {
361                 kfree(info);
362                 return AE_ERROR;
363         }
364 
365         hardware_id = info->hardware_id.string;
366         if ((hardware_id == NULL) ||
367             (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
368                 status = AE_ERROR;
369 
370         kfree(info);
371         return status;
372 }
373 
374 static acpi_status
375 acpi_memory_register_notify_handler(acpi_handle handle,
376                                     u32 level, void *ctxt, void **retv)
377 {
378         acpi_status status;
379 
380         status = is_memory_device(handle);
381         if (ACPI_FAILURE(status))
382                 return AE_OK;   /* continue */
383 
384         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
385                                              acpi_memory_device_notify, NULL);
386         /* continue */
387         return AE_OK;
388 }
389 
390 static acpi_status
391 acpi_memory_deregister_notify_handler(acpi_handle handle,
392                                       u32 level, void *ctxt, void **retv)
393 {
394         acpi_status status;
395 
396         status = is_memory_device(handle);
397         if (ACPI_FAILURE(status))
398                 return AE_OK;   /* continue */
399 
400         status = acpi_remove_notify_handler(handle,
401                                             ACPI_SYSTEM_NOTIFY,
402                                             acpi_memory_device_notify);
403 
404         return AE_OK;   /* continue */
405 }
406 
407 static const struct acpi_device_id memory_device_ids[] = {
408         {ACPI_MEMORY_DEVICE_HID, 0},
409         {"", 0},
410 };
411 MODULE_DEVICE_TABLE(acpi, memory_device_ids);
412 
413 static struct acpi_driver xen_acpi_memory_device_driver = {
414         .name = "acpi_memhotplug",
415         .class = ACPI_MEMORY_DEVICE_CLASS,
416         .ids = memory_device_ids,
417         .ops = {
418                 .add = xen_acpi_memory_device_add,
419                 .remove = xen_acpi_memory_device_remove,
420                 },
421 };
422 
423 static int __init xen_acpi_memory_device_init(void)
424 {
425         int result;
426         acpi_status status;
427 
428         if (!xen_initial_domain())
429                 return -ENODEV;
430 
431         /* unregister the stub which only used to reserve driver space */
432         xen_stub_memory_device_exit();
433 
434         result = acpi_bus_register_driver(&xen_acpi_memory_device_driver);
435         if (result < 0) {
436                 xen_stub_memory_device_init();
437                 return -ENODEV;
438         }
439 
440         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
441                                      ACPI_UINT32_MAX,
442                                      acpi_memory_register_notify_handler,
443                                      NULL, NULL, NULL);
444 
445         if (ACPI_FAILURE(status)) {
446                 pr_warn(PREFIX "walk_namespace failed\n");
447                 acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
448                 xen_stub_memory_device_init();
449                 return -ENODEV;
450         }
451 
452         acpi_hotmem_initialized = true;
453         return 0;
454 }
455 
456 static void __exit xen_acpi_memory_device_exit(void)
457 {
458         acpi_status status;
459 
460         if (!xen_initial_domain())
461                 return;
462 
463         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
464                                      ACPI_UINT32_MAX,
465                                      acpi_memory_deregister_notify_handler,
466                                      NULL, NULL, NULL);
467         if (ACPI_FAILURE(status))
468                 pr_warn(PREFIX "walk_namespace failed\n");
469 
470         acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
471 
472         /*
473          * stub reserve space again to prevent any chance of native
474          * driver loading.
475          */
476         xen_stub_memory_device_init();
477         return;
478 }
479 
480 module_init(xen_acpi_memory_device_init);
481 module_exit(xen_acpi_memory_device_exit);
482 ACPI_MODULE_NAME("xen-acpi-memhotplug");
483 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
484 MODULE_DESCRIPTION("Xen Hotplug Mem Driver");
485 MODULE_LICENSE("GPL");
486 

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