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/nmi.h>
16 #include <linux/sched.h>
17 #include <linux/smp.h>
18 #include <linux/stat.h>
19 #include <linux/stop_machine.h>
20 #include <linux/completion.h>
21 #include <linux/device.h>
22 #include <linux/delay.h>
23 #include <linux/slab.h>
24 #include <linux/stringify.h>
25 
26 #include <asm/machdep.h>
27 #include <asm/rtas.h>
28 #include "pseries.h"
29 #include "vas.h"	/* vas_migration_handler() */
30 #include "../../kernel/cacheinfo.h"
31 
32 static struct kobject *mobility_kobj;
33 
34 struct update_props_workarea {
35 	__be32 phandle;
36 	__be32 state;
37 	__be64 reserved;
38 	__be32 nprops;
39 } __packed;
40 
41 #define NODE_ACTION_MASK	0xff000000
42 #define NODE_COUNT_MASK		0x00ffffff
43 
44 #define DELETE_DT_NODE	0x01000000
45 #define UPDATE_DT_NODE	0x02000000
46 #define ADD_DT_NODE	0x03000000
47 
48 #define MIGRATION_SCOPE	(1)
49 #define PRRN_SCOPE -2
50 
51 #ifdef CONFIG_PPC_WATCHDOG
52 static unsigned int nmi_wd_lpm_factor = 200;
53 
54 #ifdef CONFIG_SYSCTL
55 static struct ctl_table nmi_wd_lpm_factor_ctl_table[] = {
56 	{
57 		.procname	= "nmi_wd_lpm_factor",
58 		.data		= &nmi_wd_lpm_factor,
59 		.maxlen		= sizeof(int),
60 		.mode		= 0644,
61 		.proc_handler	= proc_douintvec_minmax,
62 	},
63 	{}
64 };
65 static struct ctl_table nmi_wd_lpm_factor_sysctl_root[] = {
66 	{
67 		.procname       = "kernel",
68 		.mode           = 0555,
69 		.child          = nmi_wd_lpm_factor_ctl_table,
70 	},
71 	{}
72 };
73 
74 static int __init register_nmi_wd_lpm_factor_sysctl(void)
75 {
76 	register_sysctl_table(nmi_wd_lpm_factor_sysctl_root);
77 
78 	return 0;
79 }
80 device_initcall(register_nmi_wd_lpm_factor_sysctl);
81 #endif /* CONFIG_SYSCTL */
82 #endif /* CONFIG_PPC_WATCHDOG */
83 
84 static int mobility_rtas_call(int token, char *buf, s32 scope)
85 {
86 	int rc;
87 
88 	spin_lock(&rtas_data_buf_lock);
89 
90 	memcpy(rtas_data_buf, buf, RTAS_DATA_BUF_SIZE);
91 	rc = rtas_call(token, 2, 1, NULL, rtas_data_buf, scope);
92 	memcpy(buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);
93 
94 	spin_unlock(&rtas_data_buf_lock);
95 	return rc;
96 }
97 
98 static int delete_dt_node(struct device_node *dn)
99 {
100 	struct device_node *pdn;
101 	bool is_platfac;
102 
103 	pdn = of_get_parent(dn);
104 	is_platfac = of_node_is_type(dn, "ibm,platform-facilities") ||
105 		     of_node_is_type(pdn, "ibm,platform-facilities");
106 	of_node_put(pdn);
107 
108 	/*
109 	 * The drivers that bind to nodes in the platform-facilities
110 	 * hierarchy don't support node removal, and the removal directive
111 	 * from firmware is always followed by an add of an equivalent
112 	 * node. The capability (e.g. RNG, encryption, compression)
113 	 * represented by the node is never interrupted by the migration.
114 	 * So ignore changes to this part of the tree.
115 	 */
116 	if (is_platfac) {
117 		pr_notice("ignoring remove operation for %pOFfp\n", dn);
118 		return 0;
119 	}
120 
121 	pr_debug("removing node %pOFfp\n", dn);
122 	dlpar_detach_node(dn);
123 	return 0;
124 }
125 
126 static int update_dt_property(struct device_node *dn, struct property **prop,
127 			      const char *name, u32 vd, char *value)
128 {
129 	struct property *new_prop = *prop;
130 	int more = 0;
131 
132 	/* A negative 'vd' value indicates that only part of the new property
133 	 * value is contained in the buffer and we need to call
134 	 * ibm,update-properties again to get the rest of the value.
135 	 *
136 	 * A negative value is also the two's compliment of the actual value.
137 	 */
138 	if (vd & 0x80000000) {
139 		vd = ~vd + 1;
140 		more = 1;
141 	}
142 
143 	if (new_prop) {
144 		/* partial property fixup */
145 		char *new_data = kzalloc(new_prop->length + vd, GFP_KERNEL);
146 		if (!new_data)
147 			return -ENOMEM;
148 
149 		memcpy(new_data, new_prop->value, new_prop->length);
150 		memcpy(new_data + new_prop->length, value, vd);
151 
152 		kfree(new_prop->value);
153 		new_prop->value = new_data;
154 		new_prop->length += vd;
155 	} else {
156 		new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
157 		if (!new_prop)
158 			return -ENOMEM;
159 
160 		new_prop->name = kstrdup(name, GFP_KERNEL);
161 		if (!new_prop->name) {
162 			kfree(new_prop);
163 			return -ENOMEM;
164 		}
165 
166 		new_prop->length = vd;
167 		new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
168 		if (!new_prop->value) {
169 			kfree(new_prop->name);
170 			kfree(new_prop);
171 			return -ENOMEM;
172 		}
173 
174 		memcpy(new_prop->value, value, vd);
175 		*prop = new_prop;
176 	}
177 
178 	if (!more) {
179 		pr_debug("updating node %pOF property %s\n", dn, name);
180 		of_update_property(dn, new_prop);
181 		*prop = NULL;
182 	}
183 
184 	return 0;
185 }
186 
187 static int update_dt_node(struct device_node *dn, s32 scope)
188 {
189 	struct update_props_workarea *upwa;
190 	struct property *prop = NULL;
191 	int i, rc, rtas_rc;
192 	char *prop_data;
193 	char *rtas_buf;
194 	int update_properties_token;
195 	u32 nprops;
196 	u32 vd;
197 
198 	update_properties_token = rtas_token("ibm,update-properties");
199 	if (update_properties_token == RTAS_UNKNOWN_SERVICE)
200 		return -EINVAL;
201 
202 	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
203 	if (!rtas_buf)
204 		return -ENOMEM;
205 
206 	upwa = (struct update_props_workarea *)&rtas_buf[0];
207 	upwa->phandle = cpu_to_be32(dn->phandle);
208 
209 	do {
210 		rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
211 					scope);
212 		if (rtas_rc < 0)
213 			break;
214 
215 		prop_data = rtas_buf + sizeof(*upwa);
216 		nprops = be32_to_cpu(upwa->nprops);
217 
218 		/* On the first call to ibm,update-properties for a node the
219 		 * the first property value descriptor contains an empty
220 		 * property name, the property value length encoded as u32,
221 		 * and the property value is the node path being updated.
222 		 */
223 		if (*prop_data == 0) {
224 			prop_data++;
225 			vd = be32_to_cpu(*(__be32 *)prop_data);
226 			prop_data += vd + sizeof(vd);
227 			nprops--;
228 		}
229 
230 		for (i = 0; i < nprops; i++) {
231 			char *prop_name;
232 
233 			prop_name = prop_data;
234 			prop_data += strlen(prop_name) + 1;
235 			vd = be32_to_cpu(*(__be32 *)prop_data);
236 			prop_data += sizeof(vd);
237 
238 			switch (vd) {
239 			case 0x00000000:
240 				/* name only property, nothing to do */
241 				break;
242 
243 			case 0x80000000:
244 				of_remove_property(dn, of_find_property(dn,
245 							prop_name, NULL));
246 				prop = NULL;
247 				break;
248 
249 			default:
250 				rc = update_dt_property(dn, &prop, prop_name,
251 							vd, prop_data);
252 				if (rc) {
253 					pr_err("updating %s property failed: %d\n",
254 					       prop_name, rc);
255 				}
256 
257 				prop_data += vd;
258 				break;
259 			}
260 
261 			cond_resched();
262 		}
263 
264 		cond_resched();
265 	} while (rtas_rc == 1);
266 
267 	kfree(rtas_buf);
268 	return 0;
269 }
270 
271 static int add_dt_node(struct device_node *parent_dn, __be32 drc_index)
272 {
273 	struct device_node *dn;
274 	int rc;
275 
276 	dn = dlpar_configure_connector(drc_index, parent_dn);
277 	if (!dn)
278 		return -ENOENT;
279 
280 	/*
281 	 * Since delete_dt_node() ignores this node type, this is the
282 	 * necessary counterpart. We also know that a platform-facilities
283 	 * node returned from dlpar_configure_connector() has children
284 	 * attached, and dlpar_attach_node() only adds the parent, leaking
285 	 * the children. So ignore these on the add side for now.
286 	 */
287 	if (of_node_is_type(dn, "ibm,platform-facilities")) {
288 		pr_notice("ignoring add operation for %pOF\n", dn);
289 		dlpar_free_cc_nodes(dn);
290 		return 0;
291 	}
292 
293 	rc = dlpar_attach_node(dn, parent_dn);
294 	if (rc)
295 		dlpar_free_cc_nodes(dn);
296 
297 	pr_debug("added node %pOFfp\n", dn);
298 
299 	return rc;
300 }
301 
302 static int pseries_devicetree_update(s32 scope)
303 {
304 	char *rtas_buf;
305 	__be32 *data;
306 	int update_nodes_token;
307 	int rc;
308 
309 	update_nodes_token = rtas_token("ibm,update-nodes");
310 	if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
311 		return 0;
312 
313 	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
314 	if (!rtas_buf)
315 		return -ENOMEM;
316 
317 	do {
318 		rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
319 		if (rc && rc != 1)
320 			break;
321 
322 		data = (__be32 *)rtas_buf + 4;
323 		while (be32_to_cpu(*data) & NODE_ACTION_MASK) {
324 			int i;
325 			u32 action = be32_to_cpu(*data) & NODE_ACTION_MASK;
326 			u32 node_count = be32_to_cpu(*data) & NODE_COUNT_MASK;
327 
328 			data++;
329 
330 			for (i = 0; i < node_count; i++) {
331 				struct device_node *np;
332 				__be32 phandle = *data++;
333 				__be32 drc_index;
334 
335 				np = of_find_node_by_phandle(be32_to_cpu(phandle));
336 				if (!np) {
337 					pr_warn("Failed lookup: phandle 0x%x for action 0x%x\n",
338 						be32_to_cpu(phandle), action);
339 					continue;
340 				}
341 
342 				switch (action) {
343 				case DELETE_DT_NODE:
344 					delete_dt_node(np);
345 					break;
346 				case UPDATE_DT_NODE:
347 					update_dt_node(np, scope);
348 					break;
349 				case ADD_DT_NODE:
350 					drc_index = *data++;
351 					add_dt_node(np, drc_index);
352 					break;
353 				}
354 
355 				of_node_put(np);
356 				cond_resched();
357 			}
358 		}
359 
360 		cond_resched();
361 	} while (rc == 1);
362 
363 	kfree(rtas_buf);
364 	return rc;
365 }
366 
367 void post_mobility_fixup(void)
368 {
369 	int rc;
370 
371 	rtas_activate_firmware();
372 
373 	/*
374 	 * We don't want CPUs to go online/offline while the device
375 	 * tree is being updated.
376 	 */
377 	cpus_read_lock();
378 
379 	/*
380 	 * It's common for the destination firmware to replace cache
381 	 * nodes.  Release all of the cacheinfo hierarchy's references
382 	 * before updating the device tree.
383 	 */
384 	cacheinfo_teardown();
385 
386 	rc = pseries_devicetree_update(MIGRATION_SCOPE);
387 	if (rc)
388 		pr_err("device tree update failed: %d\n", rc);
389 
390 	cacheinfo_rebuild();
391 
392 	cpus_read_unlock();
393 
394 	/* Possibly switch to a new L1 flush type */
395 	pseries_setup_security_mitigations();
396 
397 	/* Reinitialise system information for hv-24x7 */
398 	read_24x7_sys_info();
399 
400 	return;
401 }
402 
403 static int poll_vasi_state(u64 handle, unsigned long *res)
404 {
405 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
406 	long hvrc;
407 	int ret;
408 
409 	hvrc = plpar_hcall(H_VASI_STATE, retbuf, handle);
410 	switch (hvrc) {
411 	case H_SUCCESS:
412 		ret = 0;
413 		*res = retbuf[0];
414 		break;
415 	case H_PARAMETER:
416 		ret = -EINVAL;
417 		break;
418 	case H_FUNCTION:
419 		ret = -EOPNOTSUPP;
420 		break;
421 	case H_HARDWARE:
422 	default:
423 		pr_err("unexpected H_VASI_STATE result %ld\n", hvrc);
424 		ret = -EIO;
425 		break;
426 	}
427 	return ret;
428 }
429 
430 static int wait_for_vasi_session_suspending(u64 handle)
431 {
432 	unsigned long state;
433 	int ret;
434 
435 	/*
436 	 * Wait for transition from H_VASI_ENABLED to
437 	 * H_VASI_SUSPENDING. Treat anything else as an error.
438 	 */
439 	while (true) {
440 		ret = poll_vasi_state(handle, &state);
441 
442 		if (ret != 0 || state == H_VASI_SUSPENDING) {
443 			break;
444 		} else if (state == H_VASI_ENABLED) {
445 			ssleep(1);
446 		} else {
447 			pr_err("unexpected H_VASI_STATE result %lu\n", state);
448 			ret = -EIO;
449 			break;
450 		}
451 	}
452 
453 	/*
454 	 * Proceed even if H_VASI_STATE is unavailable. If H_JOIN or
455 	 * ibm,suspend-me are also unimplemented, we'll recover then.
456 	 */
457 	if (ret == -EOPNOTSUPP)
458 		ret = 0;
459 
460 	return ret;
461 }
462 
463 static void wait_for_vasi_session_completed(u64 handle)
464 {
465 	unsigned long state = 0;
466 	int ret;
467 
468 	pr_info("waiting for memory transfer to complete...\n");
469 
470 	/*
471 	 * Wait for transition from H_VASI_RESUMED to H_VASI_COMPLETED.
472 	 */
473 	while (true) {
474 		ret = poll_vasi_state(handle, &state);
475 
476 		/*
477 		 * If the memory transfer is already complete and the migration
478 		 * has been cleaned up by the hypervisor, H_PARAMETER is return,
479 		 * which is translate in EINVAL by poll_vasi_state().
480 		 */
481 		if (ret == -EINVAL || (!ret && state == H_VASI_COMPLETED)) {
482 			pr_info("memory transfer completed.\n");
483 			break;
484 		}
485 
486 		if (ret) {
487 			pr_err("H_VASI_STATE return error (%d)\n", ret);
488 			break;
489 		}
490 
491 		if (state != H_VASI_RESUMED) {
492 			pr_err("unexpected H_VASI_STATE result %lu\n", state);
493 			break;
494 		}
495 
496 		msleep(500);
497 	}
498 }
499 
500 static void prod_single(unsigned int target_cpu)
501 {
502 	long hvrc;
503 	int hwid;
504 
505 	hwid = get_hard_smp_processor_id(target_cpu);
506 	hvrc = plpar_hcall_norets(H_PROD, hwid);
507 	if (hvrc == H_SUCCESS)
508 		return;
509 	pr_err_ratelimited("H_PROD of CPU %u (hwid %d) error: %ld\n",
510 			   target_cpu, hwid, hvrc);
511 }
512 
513 static void prod_others(void)
514 {
515 	unsigned int cpu;
516 
517 	for_each_online_cpu(cpu) {
518 		if (cpu != smp_processor_id())
519 			prod_single(cpu);
520 	}
521 }
522 
523 static u16 clamp_slb_size(void)
524 {
525 #ifdef CONFIG_PPC_64S_HASH_MMU
526 	u16 prev = mmu_slb_size;
527 
528 	slb_set_size(SLB_MIN_SIZE);
529 
530 	return prev;
531 #else
532 	return 0;
533 #endif
534 }
535 
536 static int do_suspend(void)
537 {
538 	u16 saved_slb_size;
539 	int status;
540 	int ret;
541 
542 	pr_info("calling ibm,suspend-me on CPU %i\n", smp_processor_id());
543 
544 	/*
545 	 * The destination processor model may have fewer SLB entries
546 	 * than the source. We reduce mmu_slb_size to a safe minimum
547 	 * before suspending in order to minimize the possibility of
548 	 * programming non-existent entries on the destination. If
549 	 * suspend fails, we restore it before returning. On success
550 	 * the OF reconfig path will update it from the new device
551 	 * tree after resuming on the destination.
552 	 */
553 	saved_slb_size = clamp_slb_size();
554 
555 	ret = rtas_ibm_suspend_me(&status);
556 	if (ret != 0) {
557 		pr_err("ibm,suspend-me error: %d\n", status);
558 		slb_set_size(saved_slb_size);
559 	}
560 
561 	return ret;
562 }
563 
564 /**
565  * struct pseries_suspend_info - State shared between CPUs for join/suspend.
566  * @counter: Threads are to increment this upon resuming from suspend
567  *           or if an error is received from H_JOIN. The thread which performs
568  *           the first increment (i.e. sets it to 1) is responsible for
569  *           waking the other threads.
570  * @done: False if join/suspend is in progress. True if the operation is
571  *        complete (successful or not).
572  */
573 struct pseries_suspend_info {
574 	atomic_t counter;
575 	bool done;
576 };
577 
578 static int do_join(void *arg)
579 {
580 	struct pseries_suspend_info *info = arg;
581 	atomic_t *counter = &info->counter;
582 	long hvrc;
583 	int ret;
584 
585 retry:
586 	/* Must ensure MSR.EE off for H_JOIN. */
587 	hard_irq_disable();
588 	hvrc = plpar_hcall_norets(H_JOIN);
589 
590 	switch (hvrc) {
591 	case H_CONTINUE:
592 		/*
593 		 * All other CPUs are offline or in H_JOIN. This CPU
594 		 * attempts the suspend.
595 		 */
596 		ret = do_suspend();
597 		break;
598 	case H_SUCCESS:
599 		/*
600 		 * The suspend is complete and this cpu has received a
601 		 * prod, or we've received a stray prod from unrelated
602 		 * code (e.g. paravirt spinlocks) and we need to join
603 		 * again.
604 		 *
605 		 * This barrier orders the return from H_JOIN above vs
606 		 * the load of info->done. It pairs with the barrier
607 		 * in the wakeup/prod path below.
608 		 */
609 		smp_mb();
610 		if (READ_ONCE(info->done) == false) {
611 			pr_info_ratelimited("premature return from H_JOIN on CPU %i, retrying",
612 					    smp_processor_id());
613 			goto retry;
614 		}
615 		ret = 0;
616 		break;
617 	case H_BAD_MODE:
618 	case H_HARDWARE:
619 	default:
620 		ret = -EIO;
621 		pr_err_ratelimited("H_JOIN error %ld on CPU %i\n",
622 				   hvrc, smp_processor_id());
623 		break;
624 	}
625 
626 	if (atomic_inc_return(counter) == 1) {
627 		pr_info("CPU %u waking all threads\n", smp_processor_id());
628 		WRITE_ONCE(info->done, true);
629 		/*
630 		 * This barrier orders the store to info->done vs subsequent
631 		 * H_PRODs to wake the other CPUs. It pairs with the barrier
632 		 * in the H_SUCCESS case above.
633 		 */
634 		smp_mb();
635 		prod_others();
636 	}
637 	/*
638 	 * Execution may have been suspended for several seconds, so
639 	 * reset the watchdog.
640 	 */
641 	touch_nmi_watchdog();
642 	return ret;
643 }
644 
645 /*
646  * Abort reason code byte 0. We use only the 'Migrating partition' value.
647  */
648 enum vasi_aborting_entity {
649 	ORCHESTRATOR        = 1,
650 	VSP_SOURCE          = 2,
651 	PARTITION_FIRMWARE  = 3,
652 	PLATFORM_FIRMWARE   = 4,
653 	VSP_TARGET          = 5,
654 	MIGRATING_PARTITION = 6,
655 };
656 
657 static void pseries_cancel_migration(u64 handle, int err)
658 {
659 	u32 reason_code;
660 	u32 detail;
661 	u8 entity;
662 	long hvrc;
663 
664 	entity = MIGRATING_PARTITION;
665 	detail = abs(err) & 0xffffff;
666 	reason_code = (entity << 24) | detail;
667 
668 	hvrc = plpar_hcall_norets(H_VASI_SIGNAL, handle,
669 				  H_VASI_SIGNAL_CANCEL, reason_code);
670 	if (hvrc)
671 		pr_err("H_VASI_SIGNAL error: %ld\n", hvrc);
672 }
673 
674 static int pseries_suspend(u64 handle)
675 {
676 	const unsigned int max_attempts = 5;
677 	unsigned int retry_interval_ms = 1;
678 	unsigned int attempt = 1;
679 	int ret;
680 
681 	while (true) {
682 		struct pseries_suspend_info info;
683 		unsigned long vasi_state;
684 		int vasi_err;
685 
686 		info = (struct pseries_suspend_info) {
687 			.counter = ATOMIC_INIT(0),
688 			.done = false,
689 		};
690 
691 		ret = stop_machine(do_join, &info, cpu_online_mask);
692 		if (ret == 0)
693 			break;
694 		/*
695 		 * Encountered an error. If the VASI stream is still
696 		 * in Suspending state, it's likely a transient
697 		 * condition related to some device in the partition
698 		 * and we can retry in the hope that the cause has
699 		 * cleared after some delay.
700 		 *
701 		 * A better design would allow drivers etc to prepare
702 		 * for the suspend and avoid conditions which prevent
703 		 * the suspend from succeeding. For now, we have this
704 		 * mitigation.
705 		 */
706 		pr_notice("Partition suspend attempt %u of %u error: %d\n",
707 			  attempt, max_attempts, ret);
708 
709 		if (attempt == max_attempts)
710 			break;
711 
712 		vasi_err = poll_vasi_state(handle, &vasi_state);
713 		if (vasi_err == 0) {
714 			if (vasi_state != H_VASI_SUSPENDING) {
715 				pr_notice("VASI state %lu after failed suspend\n",
716 					  vasi_state);
717 				break;
718 			}
719 		} else if (vasi_err != -EOPNOTSUPP) {
720 			pr_err("VASI state poll error: %d", vasi_err);
721 			break;
722 		}
723 
724 		pr_notice("Will retry partition suspend after %u ms\n",
725 			  retry_interval_ms);
726 
727 		msleep(retry_interval_ms);
728 		retry_interval_ms *= 10;
729 		attempt++;
730 	}
731 
732 	return ret;
733 }
734 
735 static int pseries_migrate_partition(u64 handle)
736 {
737 	int ret;
738 	unsigned int factor = 0;
739 
740 #ifdef CONFIG_PPC_WATCHDOG
741 	factor = nmi_wd_lpm_factor;
742 #endif
743 	ret = wait_for_vasi_session_suspending(handle);
744 	if (ret)
745 		return ret;
746 
747 	vas_migration_handler(VAS_SUSPEND);
748 
749 	if (factor)
750 		watchdog_nmi_set_timeout_pct(factor);
751 
752 	ret = pseries_suspend(handle);
753 	if (ret == 0) {
754 		post_mobility_fixup();
755 		/*
756 		 * Wait until the memory transfer is complete, so that the user
757 		 * space process returns from the syscall after the transfer is
758 		 * complete. This allows the user hooks to be executed at the
759 		 * right time.
760 		 */
761 		wait_for_vasi_session_completed(handle);
762 	} else
763 		pseries_cancel_migration(handle, ret);
764 
765 	if (factor)
766 		watchdog_nmi_set_timeout_pct(0);
767 
768 	vas_migration_handler(VAS_RESUME);
769 
770 	return ret;
771 }
772 
773 int rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
774 {
775 	return pseries_migrate_partition(handle);
776 }
777 
778 static ssize_t migration_store(struct class *class,
779 			       struct class_attribute *attr, const char *buf,
780 			       size_t count)
781 {
782 	u64 streamid;
783 	int rc;
784 
785 	rc = kstrtou64(buf, 0, &streamid);
786 	if (rc)
787 		return rc;
788 
789 	rc = pseries_migrate_partition(streamid);
790 	if (rc)
791 		return rc;
792 
793 	return count;
794 }
795 
796 /*
797  * Used by drmgr to determine the kernel behavior of the migration interface.
798  *
799  * Version 1: Performs all PAPR requirements for migration including
800  *	firmware activation and device tree update.
801  */
802 #define MIGRATION_API_VERSION	1
803 
804 static CLASS_ATTR_WO(migration);
805 static CLASS_ATTR_STRING(api_version, 0444, __stringify(MIGRATION_API_VERSION));
806 
807 static int __init mobility_sysfs_init(void)
808 {
809 	int rc;
810 
811 	mobility_kobj = kobject_create_and_add("mobility", kernel_kobj);
812 	if (!mobility_kobj)
813 		return -ENOMEM;
814 
815 	rc = sysfs_create_file(mobility_kobj, &class_attr_migration.attr);
816 	if (rc)
817 		pr_err("unable to create migration sysfs file (%d)\n", rc);
818 
819 	rc = sysfs_create_file(mobility_kobj, &class_attr_api_version.attr.attr);
820 	if (rc)
821 		pr_err("unable to create api_version sysfs file (%d)\n", rc);
822 
823 	return 0;
824 }
825 machine_device_initcall(pseries, mobility_sysfs_init);
826