1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Support for Partition Mobility/Migration
4 *
5 * Copyright (C) 2010 Nathan Fontenot
6 * Copyright (C) 2010 IBM Corporation
7 */
8
9
10#define pr_fmt(fmt) "mobility: " fmt
11
12#include <linux/cpu.h>
13#include <linux/kernel.h>
14#include <linux/kobject.h>
15#include <linux/sched.h>
16#include <linux/smp.h>
17#include <linux/stat.h>
18#include <linux/completion.h>
19#include <linux/device.h>
20#include <linux/delay.h>
21#include <linux/slab.h>
22#include <linux/stringify.h>
23
24#include <asm/machdep.h>
25#include <asm/rtas.h>
26#include "pseries.h"
27#include "../../kernel/cacheinfo.h"
28
29static struct kobject *mobility_kobj;
30
31struct update_props_workarea {
32	__be32 phandle;
33	__be32 state;
34	__be64 reserved;
35	__be32 nprops;
36} __packed;
37
38#define NODE_ACTION_MASK	0xff000000
39#define NODE_COUNT_MASK		0x00ffffff
40
41#define DELETE_DT_NODE	0x01000000
42#define UPDATE_DT_NODE	0x02000000
43#define ADD_DT_NODE	0x03000000
44
45#define MIGRATION_SCOPE	(1)
46#define PRRN_SCOPE -2
47
48static int mobility_rtas_call(int token, char *buf, s32 scope)
49{
50	int rc;
51
52	spin_lock(&rtas_data_buf_lock);
53
54	memcpy(rtas_data_buf, buf, RTAS_DATA_BUF_SIZE);
55	rc = rtas_call(token, 2, 1, NULL, rtas_data_buf, scope);
56	memcpy(buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);
57
58	spin_unlock(&rtas_data_buf_lock);
59	return rc;
60}
61
62static int delete_dt_node(struct device_node *dn)
63{
64	struct device_node *pdn;
65	bool is_platfac;
66
67	pdn = of_get_parent(dn);
68	is_platfac = of_node_is_type(dn, "ibm,platform-facilities") ||
69		     of_node_is_type(pdn, "ibm,platform-facilities");
70	of_node_put(pdn);
71
72	/*
73	 * The drivers that bind to nodes in the platform-facilities
74	 * hierarchy don't support node removal, and the removal directive
75	 * from firmware is always followed by an add of an equivalent
76	 * node. The capability (e.g. RNG, encryption, compression)
77	 * represented by the node is never interrupted by the migration.
78	 * So ignore changes to this part of the tree.
79	 */
80	if (is_platfac) {
81		pr_notice("ignoring remove operation for %pOFfp\n", dn);
82		return 0;
83	}
84
85	pr_debug("removing node %pOFfp\n", dn);
86	dlpar_detach_node(dn);
87	return 0;
88}
89
90static int update_dt_property(struct device_node *dn, struct property **prop,
91			      const char *name, u32 vd, char *value)
92{
93	struct property *new_prop = *prop;
94	int more = 0;
95
96	/* A negative 'vd' value indicates that only part of the new property
97	 * value is contained in the buffer and we need to call
98	 * ibm,update-properties again to get the rest of the value.
99	 *
100	 * A negative value is also the two's compliment of the actual value.
101	 */
102	if (vd & 0x80000000) {
103		vd = ~vd + 1;
104		more = 1;
105	}
106
107	if (new_prop) {
108		/* partial property fixup */
109		char *new_data = kzalloc(new_prop->length + vd, GFP_KERNEL);
110		if (!new_data)
111			return -ENOMEM;
112
113		memcpy(new_data, new_prop->value, new_prop->length);
114		memcpy(new_data + new_prop->length, value, vd);
115
116		kfree(new_prop->value);
117		new_prop->value = new_data;
118		new_prop->length += vd;
119	} else {
120		new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
121		if (!new_prop)
122			return -ENOMEM;
123
124		new_prop->name = kstrdup(name, GFP_KERNEL);
125		if (!new_prop->name) {
126			kfree(new_prop);
127			return -ENOMEM;
128		}
129
130		new_prop->length = vd;
131		new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
132		if (!new_prop->value) {
133			kfree(new_prop->name);
134			kfree(new_prop);
135			return -ENOMEM;
136		}
137
138		memcpy(new_prop->value, value, vd);
139		*prop = new_prop;
140	}
141
142	if (!more) {
143		pr_debug("updating node %pOF property %s\n", dn, name);
144		of_update_property(dn, new_prop);
145		*prop = NULL;
146	}
147
148	return 0;
149}
150
151static int update_dt_node(struct device_node *dn, s32 scope)
152{
153	struct update_props_workarea *upwa;
154	struct property *prop = NULL;
155	int i, rc, rtas_rc;
156	char *prop_data;
157	char *rtas_buf;
158	int update_properties_token;
159	u32 nprops;
160	u32 vd;
161
162	update_properties_token = rtas_token("ibm,update-properties");
163	if (update_properties_token == RTAS_UNKNOWN_SERVICE)
164		return -EINVAL;
165
166	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
167	if (!rtas_buf)
168		return -ENOMEM;
169
170	upwa = (struct update_props_workarea *)&rtas_buf[0];
171	upwa->phandle = cpu_to_be32(dn->phandle);
172
173	do {
174		rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
175					scope);
176		if (rtas_rc < 0)
177			break;
178
179		prop_data = rtas_buf + sizeof(*upwa);
180		nprops = be32_to_cpu(upwa->nprops);
181
182		/* On the first call to ibm,update-properties for a node the
183		 * the first property value descriptor contains an empty
184		 * property name, the property value length encoded as u32,
185		 * and the property value is the node path being updated.
186		 */
187		if (*prop_data == 0) {
188			prop_data++;
189			vd = be32_to_cpu(*(__be32 *)prop_data);
190			prop_data += vd + sizeof(vd);
191			nprops--;
192		}
193
194		for (i = 0; i < nprops; i++) {
195			char *prop_name;
196
197			prop_name = prop_data;
198			prop_data += strlen(prop_name) + 1;
199			vd = be32_to_cpu(*(__be32 *)prop_data);
200			prop_data += sizeof(vd);
201
202			switch (vd) {
203			case 0x00000000:
204				/* name only property, nothing to do */
205				break;
206
207			case 0x80000000:
208				of_remove_property(dn, of_find_property(dn,
209							prop_name, NULL));
210				prop = NULL;
211				break;
212
213			default:
214				rc = update_dt_property(dn, &prop, prop_name,
215							vd, prop_data);
216				if (rc) {
217					printk(KERN_ERR "Could not update %s"
218					       " property\n", prop_name);
219				}
220
221				prop_data += vd;
222			}
223
224			cond_resched();
225		}
226
227		cond_resched();
228	} while (rtas_rc == 1);
229
230	kfree(rtas_buf);
231	return 0;
232}
233
234static int add_dt_node(struct device_node *parent_dn, __be32 drc_index)
235{
236	struct device_node *dn;
237	int rc;
238
239	dn = dlpar_configure_connector(drc_index, parent_dn);
240	if (!dn)
241		return -ENOENT;
242
243	/*
244	 * Since delete_dt_node() ignores this node type, this is the
245	 * necessary counterpart. We also know that a platform-facilities
246	 * node returned from dlpar_configure_connector() has children
247	 * attached, and dlpar_attach_node() only adds the parent, leaking
248	 * the children. So ignore these on the add side for now.
249	 */
250	if (of_node_is_type(dn, "ibm,platform-facilities")) {
251		pr_notice("ignoring add operation for %pOF\n", dn);
252		dlpar_free_cc_nodes(dn);
253		return 0;
254	}
255
256	rc = dlpar_attach_node(dn, parent_dn);
257	if (rc)
258		dlpar_free_cc_nodes(dn);
259
260	pr_debug("added node %pOFfp\n", dn);
261
262	return rc;
263}
264
265int pseries_devicetree_update(s32 scope)
266{
267	char *rtas_buf;
268	__be32 *data;
269	int update_nodes_token;
270	int rc;
271
272	update_nodes_token = rtas_token("ibm,update-nodes");
273	if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
274		return -EINVAL;
275
276	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
277	if (!rtas_buf)
278		return -ENOMEM;
279
280	do {
281		rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
282		if (rc && rc != 1)
283			break;
284
285		data = (__be32 *)rtas_buf + 4;
286		while (be32_to_cpu(*data) & NODE_ACTION_MASK) {
287			int i;
288			u32 action = be32_to_cpu(*data) & NODE_ACTION_MASK;
289			u32 node_count = be32_to_cpu(*data) & NODE_COUNT_MASK;
290
291			data++;
292
293			for (i = 0; i < node_count; i++) {
294				struct device_node *np;
295				__be32 phandle = *data++;
296				__be32 drc_index;
297
298				np = of_find_node_by_phandle(be32_to_cpu(phandle));
299				if (!np) {
300					pr_warn("Failed lookup: phandle 0x%x for action 0x%x\n",
301						be32_to_cpu(phandle), action);
302					continue;
303				}
304
305				switch (action) {
306				case DELETE_DT_NODE:
307					delete_dt_node(np);
308					break;
309				case UPDATE_DT_NODE:
310					update_dt_node(np, scope);
311					break;
312				case ADD_DT_NODE:
313					drc_index = *data++;
314					add_dt_node(np, drc_index);
315					break;
316				}
317
318				of_node_put(np);
319				cond_resched();
320			}
321		}
322
323		cond_resched();
324	} while (rc == 1);
325
326	kfree(rtas_buf);
327	return rc;
328}
329
330void post_mobility_fixup(void)
331{
332	int rc;
333	int activate_fw_token;
334
335	activate_fw_token = rtas_token("ibm,activate-firmware");
336	if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
337		printk(KERN_ERR "Could not make post-mobility "
338		       "activate-fw call.\n");
339		return;
340	}
341
342	do {
343		rc = rtas_call(activate_fw_token, 0, 1, NULL);
344	} while (rtas_busy_delay(rc));
345
346	if (rc)
347		printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc);
348
349	/*
350	 * We don't want CPUs to go online/offline while the device
351	 * tree is being updated.
352	 */
353	cpus_read_lock();
354
355	/*
356	 * It's common for the destination firmware to replace cache
357	 * nodes.  Release all of the cacheinfo hierarchy's references
358	 * before updating the device tree.
359	 */
360	cacheinfo_teardown();
361
362	rc = pseries_devicetree_update(MIGRATION_SCOPE);
363	if (rc)
364		printk(KERN_ERR "Post-mobility device tree update "
365			"failed: %d\n", rc);
366
367	cacheinfo_rebuild();
368
369	cpus_read_unlock();
370
371	/* Possibly switch to a new L1 flush type */
372	pseries_setup_security_mitigations();
373
374	/* Reinitialise system information for hv-24x7 */
375	read_24x7_sys_info();
376
377	return;
378}
379
380static ssize_t migration_store(struct class *class,
381			       struct class_attribute *attr, const char *buf,
382			       size_t count)
383{
384	u64 streamid;
385	int rc;
386
387	rc = kstrtou64(buf, 0, &streamid);
388	if (rc)
389		return rc;
390
391	do {
392		rc = rtas_ibm_suspend_me(streamid);
393		if (rc == -EAGAIN)
394			ssleep(1);
395	} while (rc == -EAGAIN);
396
397	if (rc)
398		return rc;
399
400	post_mobility_fixup();
401
402	return count;
403}
404
405/*
406 * Used by drmgr to determine the kernel behavior of the migration interface.
407 *
408 * Version 1: Performs all PAPR requirements for migration including
409 *	firmware activation and device tree update.
410 */
411#define MIGRATION_API_VERSION	1
412
413static CLASS_ATTR_WO(migration);
414static CLASS_ATTR_STRING(api_version, 0444, __stringify(MIGRATION_API_VERSION));
415
416static int __init mobility_sysfs_init(void)
417{
418	int rc;
419
420	mobility_kobj = kobject_create_and_add("mobility", kernel_kobj);
421	if (!mobility_kobj)
422		return -ENOMEM;
423
424	rc = sysfs_create_file(mobility_kobj, &class_attr_migration.attr);
425	if (rc)
426		pr_err("unable to create migration sysfs file (%d)\n", rc);
427
428	rc = sysfs_create_file(mobility_kobj, &class_attr_api_version.attr.attr);
429	if (rc)
430		pr_err("unable to create api_version sysfs file (%d)\n", rc);
431
432	return 0;
433}
434machine_device_initcall(pseries, mobility_sysfs_init);
435