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/acpi.h>
 15#include <xen/acpi.h>
 16#include <xen/interface/platform.h>
 17#include <asm/xen/hypercall.h>
 18
 19#define PREFIX "ACPI:xen_memory_hotplug:"
 20
 21struct acpi_memory_info {
 22	struct list_head list;
 23	u64 start_addr;		/* Memory Range start physical addr */
 24	u64 length;		/* Memory Range length */
 25	unsigned short caching;	/* memory cache attribute */
 26	unsigned short write_protect;	/* memory read/write attribute */
 27				/* copied from buffer getting from _CRS */
 28	unsigned int enabled:1;
 29};
 30
 31struct acpi_memory_device {
 32	struct acpi_device *device;
 33	struct list_head res_list;
 34};
 35
 36static bool acpi_hotmem_initialized __read_mostly;
 37
 38static int xen_hotadd_memory(int pxm, struct acpi_memory_info *info)
 39{
 40	int rc;
 41	struct xen_platform_op op;
 42
 43	op.cmd = XENPF_mem_hotadd;
 44	op.u.mem_add.spfn = info->start_addr >> PAGE_SHIFT;
 45	op.u.mem_add.epfn = (info->start_addr + info->length) >> PAGE_SHIFT;
 46	op.u.mem_add.pxm = pxm;
 47
 48	rc = HYPERVISOR_dom0_op(&op);
 49	if (rc)
 50		pr_err(PREFIX "Xen Hotplug Memory Add failed on "
 51			"0x%lx -> 0x%lx, _PXM: %d, error: %d\n",
 52			(unsigned long)info->start_addr,
 53			(unsigned long)(info->start_addr + info->length),
 54			pxm, rc);
 55
 56	return rc;
 57}
 58
 59static int xen_acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 60{
 61	int pxm, result;
 62	int num_enabled = 0;
 63	struct acpi_memory_info *info;
 64
 65	if (!mem_device)
 66		return -EINVAL;
 67
 68	pxm = xen_acpi_get_pxm(mem_device->device->handle);
 69	if (pxm < 0)
 70		return pxm;
 71
 72	list_for_each_entry(info, &mem_device->res_list, list) {
 73		if (info->enabled) { /* just sanity check...*/
 74			num_enabled++;
 75			continue;
 76		}
 77
 78		if (!info->length)
 79			continue;
 80
 81		result = xen_hotadd_memory(pxm, info);
 82		if (result)
 83			continue;
 84		info->enabled = 1;
 85		num_enabled++;
 86	}
 87
 88	if (!num_enabled)
 89		return -ENODEV;
 90
 91	return 0;
 92}
 93
 94static acpi_status
 95acpi_memory_get_resource(struct acpi_resource *resource, void *context)
 96{
 97	struct acpi_memory_device *mem_device = context;
 98	struct acpi_resource_address64 address64;
 99	struct acpi_memory_info *info, *new;
100	acpi_status status;
101
102	status = acpi_resource_to_address64(resource, &address64);
103	if (ACPI_FAILURE(status) ||
104	    (address64.resource_type != ACPI_MEMORY_RANGE))
105		return AE_OK;
106
107	list_for_each_entry(info, &mem_device->res_list, list) {
108		if ((info->caching == address64.info.mem.caching) &&
109		    (info->write_protect == address64.info.mem.write_protect) &&
110		    (info->start_addr + info->length == address64.address.minimum)) {
111			info->length += address64.address.address_length;
112			return AE_OK;
113		}
114	}
115
116	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
117	if (!new)
118		return AE_ERROR;
119
120	INIT_LIST_HEAD(&new->list);
121	new->caching = address64.info.mem.caching;
122	new->write_protect = address64.info.mem.write_protect;
123	new->start_addr = address64.address.minimum;
124	new->length = address64.address.address_length;
125	list_add_tail(&new->list, &mem_device->res_list);
126
127	return AE_OK;
128}
129
130static int
131acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
132{
133	acpi_status status;
134	struct acpi_memory_info *info, *n;
135
136	if (!list_empty(&mem_device->res_list))
137		return 0;
138
139	status = acpi_walk_resources(mem_device->device->handle,
140		METHOD_NAME__CRS, acpi_memory_get_resource, mem_device);
141
142	if (ACPI_FAILURE(status)) {
143		list_for_each_entry_safe(info, n, &mem_device->res_list, list)
144			kfree(info);
145		INIT_LIST_HEAD(&mem_device->res_list);
146		return -EINVAL;
147	}
148
149	return 0;
150}
151
152static int acpi_memory_get_device(acpi_handle handle,
153				  struct acpi_memory_device **mem_device)
154{
155	struct acpi_device *device = NULL;
156	int result = 0;
157
158	acpi_scan_lock_acquire();
159
160	acpi_bus_get_device(handle, &device);
161	if (acpi_device_enumerated(device))
162		goto end;
163
164	/*
165	 * Now add the notified device.  This creates the acpi_device
166	 * and invokes .add function
167	 */
168	result = acpi_bus_scan(handle);
169	if (result) {
170		pr_warn(PREFIX "ACPI namespace scan failed\n");
171		result = -EINVAL;
172		goto out;
173	}
174	device = NULL;
175	acpi_bus_get_device(handle, &device);
176	if (!acpi_device_enumerated(device)) {
177		pr_warn(PREFIX "Missing device object\n");
178		result = -EINVAL;
179		goto out;
180	}
181
182end:
183	*mem_device = acpi_driver_data(device);
184	if (!(*mem_device)) {
185		pr_err(PREFIX "driver data not found\n");
186		result = -ENODEV;
187		goto out;
188	}
189
190out:
191	acpi_scan_lock_release();
192	return result;
193}
194
195static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
196{
197	unsigned long long current_status;
198
199	/* Get device present/absent information from the _STA */
200	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
201				"_STA", NULL, &current_status)))
202		return -ENODEV;
203	/*
204	 * Check for device status. Device should be
205	 * present/enabled/functioning.
206	 */
207	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
208	      && (current_status & ACPI_STA_DEVICE_ENABLED)
209	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
210		return -ENODEV;
211
212	return 0;
213}
214
215static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
216{
217	pr_debug(PREFIX "Xen does not support memory hotremove\n");
218
219	return -ENOSYS;
220}
221
222static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
223{
224	struct acpi_memory_device *mem_device;
225	struct acpi_device *device;
226	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
227
228	switch (event) {
229	case ACPI_NOTIFY_BUS_CHECK:
230		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
231			"\nReceived BUS CHECK notification for device\n"));
232		fallthrough;
233	case ACPI_NOTIFY_DEVICE_CHECK:
234		if (event == ACPI_NOTIFY_DEVICE_CHECK)
235			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
236			"\nReceived DEVICE CHECK notification for device\n"));
237
238		if (acpi_memory_get_device(handle, &mem_device)) {
239			pr_err(PREFIX "Cannot find driver data\n");
240			break;
241		}
242
243		ost_code = ACPI_OST_SC_SUCCESS;
244		break;
245
246	case ACPI_NOTIFY_EJECT_REQUEST:
247		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
248			"\nReceived EJECT REQUEST notification for device\n"));
249
250		acpi_scan_lock_acquire();
251		if (acpi_bus_get_device(handle, &device)) {
252			acpi_scan_lock_release();
253			pr_err(PREFIX "Device doesn't exist\n");
254			break;
255		}
256		mem_device = acpi_driver_data(device);
257		if (!mem_device) {
258			acpi_scan_lock_release();
259			pr_err(PREFIX "Driver Data is NULL\n");
260			break;
261		}
262
263		/*
264		 * TBD: implement acpi_memory_disable_device and invoke
265		 * acpi_bus_remove if Xen support hotremove in the future
266		 */
267		acpi_memory_disable_device(mem_device);
268		acpi_scan_lock_release();
269		break;
270
271	default:
272		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
273				  "Unsupported event [0x%x]\n", event));
274		/* non-hotplug event; possibly handled by other handler */
275		return;
276	}
277
278	(void) acpi_evaluate_ost(handle, event, ost_code, NULL);
279	return;
280}
281
282static int xen_acpi_memory_device_add(struct acpi_device *device)
283{
284	int result;
285	struct acpi_memory_device *mem_device = NULL;
286
287
288	if (!device)
289		return -EINVAL;
290
291	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
292	if (!mem_device)
293		return -ENOMEM;
294
295	INIT_LIST_HEAD(&mem_device->res_list);
296	mem_device->device = device;
297	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
298	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
299	device->driver_data = mem_device;
300
301	/* Get the range from the _CRS */
302	result = acpi_memory_get_device_resources(mem_device);
303	if (result) {
304		kfree(mem_device);
305		return result;
306	}
307
308	/*
309	 * For booting existed memory devices, early boot code has recognized
310	 * memory area by EFI/E820. If DSDT shows these memory devices on boot,
311	 * hotplug is not necessary for them.
312	 * For hot-added memory devices during runtime, it need hypercall to
313	 * Xen hypervisor to add memory.
314	 */
315	if (!acpi_hotmem_initialized)
316		return 0;
317
318	if (!acpi_memory_check_device(mem_device))
319		result = xen_acpi_memory_enable_device(mem_device);
320
321	return result;
322}
323
324static int xen_acpi_memory_device_remove(struct acpi_device *device)
325{
326	struct acpi_memory_device *mem_device = NULL;
327
328	if (!device || !acpi_driver_data(device))
329		return -EINVAL;
330
331	mem_device = acpi_driver_data(device);
332	kfree(mem_device);
333
334	return 0;
335}
336
337/*
338 * Helper function to check for memory device
339 */
340static acpi_status is_memory_device(acpi_handle handle)
341{
342	char *hardware_id;
343	acpi_status status;
344	struct acpi_device_info *info;
345
346	status = acpi_get_object_info(handle, &info);
347	if (ACPI_FAILURE(status))
348		return status;
349
350	if (!(info->valid & ACPI_VALID_HID)) {
351		kfree(info);
352		return AE_ERROR;
353	}
354
355	hardware_id = info->hardware_id.string;
356	if ((hardware_id == NULL) ||
357	    (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
358		status = AE_ERROR;
359
360	kfree(info);
361	return status;
362}
363
364static acpi_status
365acpi_memory_register_notify_handler(acpi_handle handle,
366				    u32 level, void *ctxt, void **retv)
367{
368	acpi_status status;
369
370	status = is_memory_device(handle);
371	if (ACPI_FAILURE(status))
372		return AE_OK;	/* continue */
373
374	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
375					     acpi_memory_device_notify, NULL);
376	/* continue */
377	return AE_OK;
378}
379
380static acpi_status
381acpi_memory_deregister_notify_handler(acpi_handle handle,
382				      u32 level, void *ctxt, void **retv)
383{
384	acpi_status status;
385
386	status = is_memory_device(handle);
387	if (ACPI_FAILURE(status))
388		return AE_OK;	/* continue */
389
390	status = acpi_remove_notify_handler(handle,
391					    ACPI_SYSTEM_NOTIFY,
392					    acpi_memory_device_notify);
393
394	return AE_OK;	/* continue */
395}
396
397static const struct acpi_device_id memory_device_ids[] = {
398	{ACPI_MEMORY_DEVICE_HID, 0},
399	{"", 0},
400};
401MODULE_DEVICE_TABLE(acpi, memory_device_ids);
402
403static struct acpi_driver xen_acpi_memory_device_driver = {
404	.name = "acpi_memhotplug",
405	.class = ACPI_MEMORY_DEVICE_CLASS,
406	.ids = memory_device_ids,
407	.ops = {
408		.add = xen_acpi_memory_device_add,
409		.remove = xen_acpi_memory_device_remove,
410		},
411};
412
413static int __init xen_acpi_memory_device_init(void)
414{
415	int result;
416	acpi_status status;
417
418	if (!xen_initial_domain())
419		return -ENODEV;
420
421	/* unregister the stub which only used to reserve driver space */
422	xen_stub_memory_device_exit();
423
424	result = acpi_bus_register_driver(&xen_acpi_memory_device_driver);
425	if (result < 0) {
426		xen_stub_memory_device_init();
427		return -ENODEV;
428	}
429
430	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
431				     ACPI_UINT32_MAX,
432				     acpi_memory_register_notify_handler,
433				     NULL, NULL, NULL);
434
435	if (ACPI_FAILURE(status)) {
436		pr_warn(PREFIX "walk_namespace failed\n");
437		acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
438		xen_stub_memory_device_init();
439		return -ENODEV;
440	}
441
442	acpi_hotmem_initialized = true;
443	return 0;
444}
445
446static void __exit xen_acpi_memory_device_exit(void)
447{
448	acpi_status status;
449
450	if (!xen_initial_domain())
451		return;
452
453	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
454				     ACPI_UINT32_MAX,
455				     acpi_memory_deregister_notify_handler,
456				     NULL, NULL, NULL);
457	if (ACPI_FAILURE(status))
458		pr_warn(PREFIX "walk_namespace failed\n");
459
460	acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
461
462	/*
463	 * stub reserve space again to prevent any chance of native
464	 * driver loading.
465	 */
466	xen_stub_memory_device_init();
467	return;
468}
469
470module_init(xen_acpi_memory_device_init);
471module_exit(xen_acpi_memory_device_exit);
472ACPI_MODULE_NAME("xen-acpi-memhotplug");
473MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
474MODULE_DESCRIPTION("Xen Hotplug Mem Driver");
475MODULE_LICENSE("GPL");