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/nmi.h>
28 #include <asm/rtas.h>
29 #include "pseries.h"
30 #include "vas.h"	/* vas_migration_handler() */
31 #include "../../kernel/cacheinfo.h"
32 
33 static struct kobject *mobility_kobj;
34 
35 struct update_props_workarea {
36 	__be32 phandle;
37 	__be32 state;
38 	__be64 reserved;
39 	__be32 nprops;
40 } __packed;
41 
42 #define NODE_ACTION_MASK	0xff000000
43 #define NODE_COUNT_MASK		0x00ffffff
44 
45 #define DELETE_DT_NODE	0x01000000
46 #define UPDATE_DT_NODE	0x02000000
47 #define ADD_DT_NODE	0x03000000
48 
49 #define MIGRATION_SCOPE	(1)
50 #define PRRN_SCOPE -2
51 
52 #ifdef CONFIG_PPC_WATCHDOG
53 static unsigned int nmi_wd_lpm_factor = 200;
54 
55 #ifdef CONFIG_SYSCTL
56 static struct ctl_table nmi_wd_lpm_factor_ctl_table[] = {
57 	{
58 		.procname	= "nmi_wd_lpm_factor",
59 		.data		= &nmi_wd_lpm_factor,
60 		.maxlen		= sizeof(int),
61 		.mode		= 0644,
62 		.proc_handler	= proc_douintvec_minmax,
63 	},
64 	{}
65 };
66 
67 static int __init register_nmi_wd_lpm_factor_sysctl(void)
68 {
69 	register_sysctl("kernel", nmi_wd_lpm_factor_ctl_table);
70 
71 	return 0;
72 }
73 device_initcall(register_nmi_wd_lpm_factor_sysctl);
74 #endif /* CONFIG_SYSCTL */
75 #endif /* CONFIG_PPC_WATCHDOG */
76 
77 static int mobility_rtas_call(int token, char *buf, s32 scope)
78 {
79 	int rc;
80 
81 	spin_lock(&rtas_data_buf_lock);
82 
83 	memcpy(rtas_data_buf, buf, RTAS_DATA_BUF_SIZE);
84 	rc = rtas_call(token, 2, 1, NULL, rtas_data_buf, scope);
85 	memcpy(buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);
86 
87 	spin_unlock(&rtas_data_buf_lock);
88 	return rc;
89 }
90 
91 static int delete_dt_node(struct device_node *dn)
92 {
93 	struct device_node *pdn;
94 	bool is_platfac;
95 
96 	pdn = of_get_parent(dn);
97 	is_platfac = of_node_is_type(dn, "ibm,platform-facilities") ||
98 		     of_node_is_type(pdn, "ibm,platform-facilities");
99 	of_node_put(pdn);
100 
101 	/*
102 	 * The drivers that bind to nodes in the platform-facilities
103 	 * hierarchy don't support node removal, and the removal directive
104 	 * from firmware is always followed by an add of an equivalent
105 	 * node. The capability (e.g. RNG, encryption, compression)
106 	 * represented by the node is never interrupted by the migration.
107 	 * So ignore changes to this part of the tree.
108 	 */
109 	if (is_platfac) {
110 		pr_notice("ignoring remove operation for %pOFfp\n", dn);
111 		return 0;
112 	}
113 
114 	pr_debug("removing node %pOFfp\n", dn);
115 	dlpar_detach_node(dn);
116 	return 0;
117 }
118 
119 static int update_dt_property(struct device_node *dn, struct property **prop,
120 			      const char *name, u32 vd, char *value)
121 {
122 	struct property *new_prop = *prop;
123 	int more = 0;
124 
125 	/* A negative 'vd' value indicates that only part of the new property
126 	 * value is contained in the buffer and we need to call
127 	 * ibm,update-properties again to get the rest of the value.
128 	 *
129 	 * A negative value is also the two's compliment of the actual value.
130 	 */
131 	if (vd & 0x80000000) {
132 		vd = ~vd + 1;
133 		more = 1;
134 	}
135 
136 	if (new_prop) {
137 		/* partial property fixup */
138 		char *new_data = kzalloc(new_prop->length + vd, GFP_KERNEL);
139 		if (!new_data)
140 			return -ENOMEM;
141 
142 		memcpy(new_data, new_prop->value, new_prop->length);
143 		memcpy(new_data + new_prop->length, value, vd);
144 
145 		kfree(new_prop->value);
146 		new_prop->value = new_data;
147 		new_prop->length += vd;
148 	} else {
149 		new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
150 		if (!new_prop)
151 			return -ENOMEM;
152 
153 		new_prop->name = kstrdup(name, GFP_KERNEL);
154 		if (!new_prop->name) {
155 			kfree(new_prop);
156 			return -ENOMEM;
157 		}
158 
159 		new_prop->length = vd;
160 		new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
161 		if (!new_prop->value) {
162 			kfree(new_prop->name);
163 			kfree(new_prop);
164 			return -ENOMEM;
165 		}
166 
167 		memcpy(new_prop->value, value, vd);
168 		*prop = new_prop;
169 	}
170 
171 	if (!more) {
172 		pr_debug("updating node %pOF property %s\n", dn, name);
173 		of_update_property(dn, new_prop);
174 		*prop = NULL;
175 	}
176 
177 	return 0;
178 }
179 
180 static int update_dt_node(struct device_node *dn, s32 scope)
181 {
182 	struct update_props_workarea *upwa;
183 	struct property *prop = NULL;
184 	int i, rc, rtas_rc;
185 	char *prop_data;
186 	char *rtas_buf;
187 	int update_properties_token;
188 	u32 nprops;
189 	u32 vd;
190 
191 	update_properties_token = rtas_function_token(RTAS_FN_IBM_UPDATE_PROPERTIES);
192 	if (update_properties_token == RTAS_UNKNOWN_SERVICE)
193 		return -EINVAL;
194 
195 	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
196 	if (!rtas_buf)
197 		return -ENOMEM;
198 
199 	upwa = (struct update_props_workarea *)&rtas_buf[0];
200 	upwa->phandle = cpu_to_be32(dn->phandle);
201 
202 	do {
203 		rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
204 					scope);
205 		if (rtas_rc < 0)
206 			break;
207 
208 		prop_data = rtas_buf + sizeof(*upwa);
209 		nprops = be32_to_cpu(upwa->nprops);
210 
211 		/* On the first call to ibm,update-properties for a node the
212 		 * first property value descriptor contains an empty
213 		 * property name, the property value length encoded as u32,
214 		 * and the property value is the node path being updated.
215 		 */
216 		if (*prop_data == 0) {
217 			prop_data++;
218 			vd = be32_to_cpu(*(__be32 *)prop_data);
219 			prop_data += vd + sizeof(vd);
220 			nprops--;
221 		}
222 
223 		for (i = 0; i < nprops; i++) {
224 			char *prop_name;
225 
226 			prop_name = prop_data;
227 			prop_data += strlen(prop_name) + 1;
228 			vd = be32_to_cpu(*(__be32 *)prop_data);
229 			prop_data += sizeof(vd);
230 
231 			switch (vd) {
232 			case 0x00000000:
233 				/* name only property, nothing to do */
234 				break;
235 
236 			case 0x80000000:
237 				of_remove_property(dn, of_find_property(dn,
238 							prop_name, NULL));
239 				prop = NULL;
240 				break;
241 
242 			default:
243 				rc = update_dt_property(dn, &prop, prop_name,
244 							vd, prop_data);
245 				if (rc) {
246 					pr_err("updating %s property failed: %d\n",
247 					       prop_name, rc);
248 				}
249 
250 				prop_data += vd;
251 				break;
252 			}
253 
254 			cond_resched();
255 		}
256 
257 		cond_resched();
258 	} while (rtas_rc == 1);
259 
260 	kfree(rtas_buf);
261 	return 0;
262 }
263 
264 static int add_dt_node(struct device_node *parent_dn, __be32 drc_index)
265 {
266 	struct device_node *dn;
267 	int rc;
268 
269 	dn = dlpar_configure_connector(drc_index, parent_dn);
270 	if (!dn)
271 		return -ENOENT;
272 
273 	/*
274 	 * Since delete_dt_node() ignores this node type, this is the
275 	 * necessary counterpart. We also know that a platform-facilities
276 	 * node returned from dlpar_configure_connector() has children
277 	 * attached, and dlpar_attach_node() only adds the parent, leaking
278 	 * the children. So ignore these on the add side for now.
279 	 */
280 	if (of_node_is_type(dn, "ibm,platform-facilities")) {
281 		pr_notice("ignoring add operation for %pOF\n", dn);
282 		dlpar_free_cc_nodes(dn);
283 		return 0;
284 	}
285 
286 	rc = dlpar_attach_node(dn, parent_dn);
287 	if (rc)
288 		dlpar_free_cc_nodes(dn);
289 
290 	pr_debug("added node %pOFfp\n", dn);
291 
292 	return rc;
293 }
294 
295 static int pseries_devicetree_update(s32 scope)
296 {
297 	char *rtas_buf;
298 	__be32 *data;
299 	int update_nodes_token;
300 	int rc;
301 
302 	update_nodes_token = rtas_function_token(RTAS_FN_IBM_UPDATE_NODES);
303 	if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
304 		return 0;
305 
306 	rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
307 	if (!rtas_buf)
308 		return -ENOMEM;
309 
310 	do {
311 		rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
312 		if (rc && rc != 1)
313 			break;
314 
315 		data = (__be32 *)rtas_buf + 4;
316 		while (be32_to_cpu(*data) & NODE_ACTION_MASK) {
317 			int i;
318 			u32 action = be32_to_cpu(*data) & NODE_ACTION_MASK;
319 			u32 node_count = be32_to_cpu(*data) & NODE_COUNT_MASK;
320 
321 			data++;
322 
323 			for (i = 0; i < node_count; i++) {
324 				struct device_node *np;
325 				__be32 phandle = *data++;
326 				__be32 drc_index;
327 
328 				np = of_find_node_by_phandle(be32_to_cpu(phandle));
329 				if (!np) {
330 					pr_warn("Failed lookup: phandle 0x%x for action 0x%x\n",
331 						be32_to_cpu(phandle), action);
332 					continue;
333 				}
334 
335 				switch (action) {
336 				case DELETE_DT_NODE:
337 					delete_dt_node(np);
338 					break;
339 				case UPDATE_DT_NODE:
340 					update_dt_node(np, scope);
341 					break;
342 				case ADD_DT_NODE:
343 					drc_index = *data++;
344 					add_dt_node(np, drc_index);
345 					break;
346 				}
347 
348 				of_node_put(np);
349 				cond_resched();
350 			}
351 		}
352 
353 		cond_resched();
354 	} while (rc == 1);
355 
356 	kfree(rtas_buf);
357 	return rc;
358 }
359 
360 void post_mobility_fixup(void)
361 {
362 	int rc;
363 
364 	rtas_activate_firmware();
365 
366 	/*
367 	 * We don't want CPUs to go online/offline while the device
368 	 * tree is being updated.
369 	 */
370 	cpus_read_lock();
371 
372 	/*
373 	 * It's common for the destination firmware to replace cache
374 	 * nodes.  Release all of the cacheinfo hierarchy's references
375 	 * before updating the device tree.
376 	 */
377 	cacheinfo_teardown();
378 
379 	rc = pseries_devicetree_update(MIGRATION_SCOPE);
380 	if (rc)
381 		pr_err("device tree update failed: %d\n", rc);
382 
383 	cacheinfo_rebuild();
384 
385 	cpus_read_unlock();
386 
387 	/* Possibly switch to a new L1 flush type */
388 	pseries_setup_security_mitigations();
389 
390 	/* Reinitialise system information for hv-24x7 */
391 	read_24x7_sys_info();
392 
393 	return;
394 }
395 
396 static int poll_vasi_state(u64 handle, unsigned long *res)
397 {
398 	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
399 	long hvrc;
400 	int ret;
401 
402 	hvrc = plpar_hcall(H_VASI_STATE, retbuf, handle);
403 	switch (hvrc) {
404 	case H_SUCCESS:
405 		ret = 0;
406 		*res = retbuf[0];
407 		break;
408 	case H_PARAMETER:
409 		ret = -EINVAL;
410 		break;
411 	case H_FUNCTION:
412 		ret = -EOPNOTSUPP;
413 		break;
414 	case H_HARDWARE:
415 	default:
416 		pr_err("unexpected H_VASI_STATE result %ld\n", hvrc);
417 		ret = -EIO;
418 		break;
419 	}
420 	return ret;
421 }
422 
423 static int wait_for_vasi_session_suspending(u64 handle)
424 {
425 	unsigned long state;
426 	int ret;
427 
428 	/*
429 	 * Wait for transition from H_VASI_ENABLED to
430 	 * H_VASI_SUSPENDING. Treat anything else as an error.
431 	 */
432 	while (true) {
433 		ret = poll_vasi_state(handle, &state);
434 
435 		if (ret != 0 || state == H_VASI_SUSPENDING) {
436 			break;
437 		} else if (state == H_VASI_ENABLED) {
438 			ssleep(1);
439 		} else {
440 			pr_err("unexpected H_VASI_STATE result %lu\n", state);
441 			ret = -EIO;
442 			break;
443 		}
444 	}
445 
446 	/*
447 	 * Proceed even if H_VASI_STATE is unavailable. If H_JOIN or
448 	 * ibm,suspend-me are also unimplemented, we'll recover then.
449 	 */
450 	if (ret == -EOPNOTSUPP)
451 		ret = 0;
452 
453 	return ret;
454 }
455 
456 static void wait_for_vasi_session_completed(u64 handle)
457 {
458 	unsigned long state = 0;
459 	int ret;
460 
461 	pr_info("waiting for memory transfer to complete...\n");
462 
463 	/*
464 	 * Wait for transition from H_VASI_RESUMED to H_VASI_COMPLETED.
465 	 */
466 	while (true) {
467 		ret = poll_vasi_state(handle, &state);
468 
469 		/*
470 		 * If the memory transfer is already complete and the migration
471 		 * has been cleaned up by the hypervisor, H_PARAMETER is return,
472 		 * which is translate in EINVAL by poll_vasi_state().
473 		 */
474 		if (ret == -EINVAL || (!ret && state == H_VASI_COMPLETED)) {
475 			pr_info("memory transfer completed.\n");
476 			break;
477 		}
478 
479 		if (ret) {
480 			pr_err("H_VASI_STATE return error (%d)\n", ret);
481 			break;
482 		}
483 
484 		if (state != H_VASI_RESUMED) {
485 			pr_err("unexpected H_VASI_STATE result %lu\n", state);
486 			break;
487 		}
488 
489 		msleep(500);
490 	}
491 }
492 
493 static void prod_single(unsigned int target_cpu)
494 {
495 	long hvrc;
496 	int hwid;
497 
498 	hwid = get_hard_smp_processor_id(target_cpu);
499 	hvrc = plpar_hcall_norets(H_PROD, hwid);
500 	if (hvrc == H_SUCCESS)
501 		return;
502 	pr_err_ratelimited("H_PROD of CPU %u (hwid %d) error: %ld\n",
503 			   target_cpu, hwid, hvrc);
504 }
505 
506 static void prod_others(void)
507 {
508 	unsigned int cpu;
509 
510 	for_each_online_cpu(cpu) {
511 		if (cpu != smp_processor_id())
512 			prod_single(cpu);
513 	}
514 }
515 
516 static u16 clamp_slb_size(void)
517 {
518 #ifdef CONFIG_PPC_64S_HASH_MMU
519 	u16 prev = mmu_slb_size;
520 
521 	slb_set_size(SLB_MIN_SIZE);
522 
523 	return prev;
524 #else
525 	return 0;
526 #endif
527 }
528 
529 static int do_suspend(void)
530 {
531 	u16 saved_slb_size;
532 	int status;
533 	int ret;
534 
535 	pr_info("calling ibm,suspend-me on CPU %i\n", smp_processor_id());
536 
537 	/*
538 	 * The destination processor model may have fewer SLB entries
539 	 * than the source. We reduce mmu_slb_size to a safe minimum
540 	 * before suspending in order to minimize the possibility of
541 	 * programming non-existent entries on the destination. If
542 	 * suspend fails, we restore it before returning. On success
543 	 * the OF reconfig path will update it from the new device
544 	 * tree after resuming on the destination.
545 	 */
546 	saved_slb_size = clamp_slb_size();
547 
548 	ret = rtas_ibm_suspend_me(&status);
549 	if (ret != 0) {
550 		pr_err("ibm,suspend-me error: %d\n", status);
551 		slb_set_size(saved_slb_size);
552 	}
553 
554 	return ret;
555 }
556 
557 /**
558  * struct pseries_suspend_info - State shared between CPUs for join/suspend.
559  * @counter: Threads are to increment this upon resuming from suspend
560  *           or if an error is received from H_JOIN. The thread which performs
561  *           the first increment (i.e. sets it to 1) is responsible for
562  *           waking the other threads.
563  * @done: False if join/suspend is in progress. True if the operation is
564  *        complete (successful or not).
565  */
566 struct pseries_suspend_info {
567 	atomic_t counter;
568 	bool done;
569 };
570 
571 static int do_join(void *arg)
572 {
573 	struct pseries_suspend_info *info = arg;
574 	atomic_t *counter = &info->counter;
575 	long hvrc;
576 	int ret;
577 
578 retry:
579 	/* Must ensure MSR.EE off for H_JOIN. */
580 	hard_irq_disable();
581 	hvrc = plpar_hcall_norets(H_JOIN);
582 
583 	switch (hvrc) {
584 	case H_CONTINUE:
585 		/*
586 		 * All other CPUs are offline or in H_JOIN. This CPU
587 		 * attempts the suspend.
588 		 */
589 		ret = do_suspend();
590 		break;
591 	case H_SUCCESS:
592 		/*
593 		 * The suspend is complete and this cpu has received a
594 		 * prod, or we've received a stray prod from unrelated
595 		 * code (e.g. paravirt spinlocks) and we need to join
596 		 * again.
597 		 *
598 		 * This barrier orders the return from H_JOIN above vs
599 		 * the load of info->done. It pairs with the barrier
600 		 * in the wakeup/prod path below.
601 		 */
602 		smp_mb();
603 		if (READ_ONCE(info->done) == false) {
604 			pr_info_ratelimited("premature return from H_JOIN on CPU %i, retrying",
605 					    smp_processor_id());
606 			goto retry;
607 		}
608 		ret = 0;
609 		break;
610 	case H_BAD_MODE:
611 	case H_HARDWARE:
612 	default:
613 		ret = -EIO;
614 		pr_err_ratelimited("H_JOIN error %ld on CPU %i\n",
615 				   hvrc, smp_processor_id());
616 		break;
617 	}
618 
619 	if (atomic_inc_return(counter) == 1) {
620 		pr_info("CPU %u waking all threads\n", smp_processor_id());
621 		WRITE_ONCE(info->done, true);
622 		/*
623 		 * This barrier orders the store to info->done vs subsequent
624 		 * H_PRODs to wake the other CPUs. It pairs with the barrier
625 		 * in the H_SUCCESS case above.
626 		 */
627 		smp_mb();
628 		prod_others();
629 	}
630 	/*
631 	 * Execution may have been suspended for several seconds, so reset
632 	 * the watchdogs. touch_nmi_watchdog() also touches the soft lockup
633 	 * watchdog.
634 	 */
635 	rcu_cpu_stall_reset();
636 	touch_nmi_watchdog();
637 
638 	return ret;
639 }
640 
641 /*
642  * Abort reason code byte 0. We use only the 'Migrating partition' value.
643  */
644 enum vasi_aborting_entity {
645 	ORCHESTRATOR        = 1,
646 	VSP_SOURCE          = 2,
647 	PARTITION_FIRMWARE  = 3,
648 	PLATFORM_FIRMWARE   = 4,
649 	VSP_TARGET          = 5,
650 	MIGRATING_PARTITION = 6,
651 };
652 
653 static void pseries_cancel_migration(u64 handle, int err)
654 {
655 	u32 reason_code;
656 	u32 detail;
657 	u8 entity;
658 	long hvrc;
659 
660 	entity = MIGRATING_PARTITION;
661 	detail = abs(err) & 0xffffff;
662 	reason_code = (entity << 24) | detail;
663 
664 	hvrc = plpar_hcall_norets(H_VASI_SIGNAL, handle,
665 				  H_VASI_SIGNAL_CANCEL, reason_code);
666 	if (hvrc)
667 		pr_err("H_VASI_SIGNAL error: %ld\n", hvrc);
668 }
669 
670 static int pseries_suspend(u64 handle)
671 {
672 	const unsigned int max_attempts = 5;
673 	unsigned int retry_interval_ms = 1;
674 	unsigned int attempt = 1;
675 	int ret;
676 
677 	while (true) {
678 		struct pseries_suspend_info info;
679 		unsigned long vasi_state;
680 		int vasi_err;
681 
682 		info = (struct pseries_suspend_info) {
683 			.counter = ATOMIC_INIT(0),
684 			.done = false,
685 		};
686 
687 		ret = stop_machine(do_join, &info, cpu_online_mask);
688 		if (ret == 0)
689 			break;
690 		/*
691 		 * Encountered an error. If the VASI stream is still
692 		 * in Suspending state, it's likely a transient
693 		 * condition related to some device in the partition
694 		 * and we can retry in the hope that the cause has
695 		 * cleared after some delay.
696 		 *
697 		 * A better design would allow drivers etc to prepare
698 		 * for the suspend and avoid conditions which prevent
699 		 * the suspend from succeeding. For now, we have this
700 		 * mitigation.
701 		 */
702 		pr_notice("Partition suspend attempt %u of %u error: %d\n",
703 			  attempt, max_attempts, ret);
704 
705 		if (attempt == max_attempts)
706 			break;
707 
708 		vasi_err = poll_vasi_state(handle, &vasi_state);
709 		if (vasi_err == 0) {
710 			if (vasi_state != H_VASI_SUSPENDING) {
711 				pr_notice("VASI state %lu after failed suspend\n",
712 					  vasi_state);
713 				break;
714 			}
715 		} else if (vasi_err != -EOPNOTSUPP) {
716 			pr_err("VASI state poll error: %d", vasi_err);
717 			break;
718 		}
719 
720 		pr_notice("Will retry partition suspend after %u ms\n",
721 			  retry_interval_ms);
722 
723 		msleep(retry_interval_ms);
724 		retry_interval_ms *= 10;
725 		attempt++;
726 	}
727 
728 	return ret;
729 }
730 
731 static int pseries_migrate_partition(u64 handle)
732 {
733 	int ret;
734 	unsigned int factor = 0;
735 
736 #ifdef CONFIG_PPC_WATCHDOG
737 	factor = nmi_wd_lpm_factor;
738 #endif
739 	/*
740 	 * When the migration is initiated, the hypervisor changes VAS
741 	 * mappings to prepare before OS gets the notification and
742 	 * closes all VAS windows. NX generates continuous faults during
743 	 * this time and the user space can not differentiate these
744 	 * faults from the migration event. So reduce this time window
745 	 * by closing VAS windows at the beginning of this function.
746 	 */
747 	vas_migration_handler(VAS_SUSPEND);
748 
749 	ret = wait_for_vasi_session_suspending(handle);
750 	if (ret)
751 		goto out;
752 
753 	if (factor)
754 		watchdog_hardlockup_set_timeout_pct(factor);
755 
756 	ret = pseries_suspend(handle);
757 	if (ret == 0) {
758 		post_mobility_fixup();
759 		/*
760 		 * Wait until the memory transfer is complete, so that the user
761 		 * space process returns from the syscall after the transfer is
762 		 * complete. This allows the user hooks to be executed at the
763 		 * right time.
764 		 */
765 		wait_for_vasi_session_completed(handle);
766 	} else
767 		pseries_cancel_migration(handle, ret);
768 
769 	if (factor)
770 		watchdog_hardlockup_set_timeout_pct(0);
771 
772 out:
773 	vas_migration_handler(VAS_RESUME);
774 
775 	return ret;
776 }
777 
778 int rtas_syscall_dispatch_ibm_suspend_me(u64 handle)
779 {
780 	return pseries_migrate_partition(handle);
781 }
782 
783 static ssize_t migration_store(const struct class *class,
784 			       const struct class_attribute *attr, const char *buf,
785 			       size_t count)
786 {
787 	u64 streamid;
788 	int rc;
789 
790 	rc = kstrtou64(buf, 0, &streamid);
791 	if (rc)
792 		return rc;
793 
794 	rc = pseries_migrate_partition(streamid);
795 	if (rc)
796 		return rc;
797 
798 	return count;
799 }
800 
801 /*
802  * Used by drmgr to determine the kernel behavior of the migration interface.
803  *
804  * Version 1: Performs all PAPR requirements for migration including
805  *	firmware activation and device tree update.
806  */
807 #define MIGRATION_API_VERSION	1
808 
809 static CLASS_ATTR_WO(migration);
810 static CLASS_ATTR_STRING(api_version, 0444, __stringify(MIGRATION_API_VERSION));
811 
812 static int __init mobility_sysfs_init(void)
813 {
814 	int rc;
815 
816 	mobility_kobj = kobject_create_and_add("mobility", kernel_kobj);
817 	if (!mobility_kobj)
818 		return -ENOMEM;
819 
820 	rc = sysfs_create_file(mobility_kobj, &class_attr_migration.attr);
821 	if (rc)
822 		pr_err("unable to create migration sysfs file (%d)\n", rc);
823 
824 	rc = sysfs_create_file(mobility_kobj, &class_attr_api_version.attr.attr);
825 	if (rc)
826 		pr_err("unable to create api_version sysfs file (%d)\n", rc);
827 
828 	return 0;
829 }
830 machine_device_initcall(pseries, mobility_sysfs_init);
831