1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
7 * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
8 */
9
10/*
11 * Cross Partition Communication (XPC) partition support.
12 *
13 *	This is the part of XPC that detects the presence/absence of
14 *	other partitions. It provides a heartbeat and monitors the
15 *	heartbeats of other partitions.
16 *
17 */
18
19#include <linux/device.h>
20#include <linux/hardirq.h>
21#include <linux/slab.h>
22#include "xpc.h"
23#include <asm/uv/uv_hub.h>
24
25/* XPC is exiting flag */
26int xpc_exiting;
27
28/* this partition's reserved page pointers */
29struct xpc_rsvd_page *xpc_rsvd_page;
30static unsigned long *xpc_part_nasids;
31unsigned long *xpc_mach_nasids;
32
33static int xpc_nasid_mask_nbytes;	/* #of bytes in nasid mask */
34int xpc_nasid_mask_nlongs;	/* #of longs in nasid mask */
35
36struct xpc_partition *xpc_partitions;
37
38/*
39 * Guarantee that the kmalloc'd memory is cacheline aligned.
40 */
41void *
42xpc_kmalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
43{
44	/* see if kmalloc will give us cachline aligned memory by default */
45	*base = kmalloc(size, flags);
46	if (*base == NULL)
47		return NULL;
48
49	if ((u64)*base == L1_CACHE_ALIGN((u64)*base))
50		return *base;
51
52	kfree(*base);
53
54	/* nope, we'll have to do it ourselves */
55	*base = kmalloc(size + L1_CACHE_BYTES, flags);
56	if (*base == NULL)
57		return NULL;
58
59	return (void *)L1_CACHE_ALIGN((u64)*base);
60}
61
62/*
63 * Given a nasid, get the physical address of the  partition's reserved page
64 * for that nasid. This function returns 0 on any error.
65 */
66static unsigned long
67xpc_get_rsvd_page_pa(int nasid)
68{
69	enum xp_retval ret;
70	u64 cookie = 0;
71	unsigned long rp_pa = nasid;	/* seed with nasid */
72	size_t len = 0;
73	size_t buf_len = 0;
74	void *buf = NULL;
75	void *buf_base = NULL;
76	enum xp_retval (*get_partition_rsvd_page_pa)
77		(void *, u64 *, unsigned long *, size_t *) =
78		xpc_arch_ops.get_partition_rsvd_page_pa;
79
80	while (1) {
81
82		/* !!! rp_pa will need to be _gpa on UV.
83		 * ??? So do we save it into the architecture specific parts
84		 * ??? of the xpc_partition structure? Do we rename this
85		 * ??? function or have two versions? Rename rp_pa for UV to
86		 * ??? rp_gpa?
87		 */
88		ret = get_partition_rsvd_page_pa(buf, &cookie, &rp_pa, &len);
89
90		dev_dbg(xpc_part, "SAL returned with ret=%d, cookie=0x%016lx, "
91			"address=0x%016lx, len=0x%016lx\n", ret,
92			(unsigned long)cookie, rp_pa, len);
93
94		if (ret != xpNeedMoreInfo)
95			break;
96
97		if (len > buf_len) {
98			kfree(buf_base);
99			buf_len = L1_CACHE_ALIGN(len);
100			buf = xpc_kmalloc_cacheline_aligned(buf_len, GFP_KERNEL,
101							    &buf_base);
102			if (buf_base == NULL) {
103				dev_err(xpc_part, "unable to kmalloc "
104					"len=0x%016lx\n", buf_len);
105				ret = xpNoMemory;
106				break;
107			}
108		}
109
110		ret = xp_remote_memcpy(xp_pa(buf), rp_pa, len);
111		if (ret != xpSuccess) {
112			dev_dbg(xpc_part, "xp_remote_memcpy failed %d\n", ret);
113			break;
114		}
115	}
116
117	kfree(buf_base);
118
119	if (ret != xpSuccess)
120		rp_pa = 0;
121
122	dev_dbg(xpc_part, "reserved page at phys address 0x%016lx\n", rp_pa);
123	return rp_pa;
124}
125
126/*
127 * Fill the partition reserved page with the information needed by
128 * other partitions to discover we are alive and establish initial
129 * communications.
130 */
131int
132xpc_setup_rsvd_page(void)
133{
134	int ret;
135	struct xpc_rsvd_page *rp;
136	unsigned long rp_pa;
137	unsigned long new_ts_jiffies;
138
139	/* get the local reserved page's address */
140
141	preempt_disable();
142	rp_pa = xpc_get_rsvd_page_pa(xp_cpu_to_nasid(smp_processor_id()));
143	preempt_enable();
144	if (rp_pa == 0) {
145		dev_err(xpc_part, "SAL failed to locate the reserved page\n");
146		return -ESRCH;
147	}
148	rp = (struct xpc_rsvd_page *)__va(xp_socket_pa(rp_pa));
149
150	if (rp->SAL_version < 3) {
151		/* SAL_versions < 3 had a SAL_partid defined as a u8 */
152		rp->SAL_partid &= 0xff;
153	}
154	BUG_ON(rp->SAL_partid != xp_partition_id);
155
156	if (rp->SAL_partid < 0 || rp->SAL_partid >= xp_max_npartitions) {
157		dev_err(xpc_part, "the reserved page's partid of %d is outside "
158			"supported range (< 0 || >= %d)\n", rp->SAL_partid,
159			xp_max_npartitions);
160		return -EINVAL;
161	}
162
163	rp->version = XPC_RP_VERSION;
164	rp->max_npartitions = xp_max_npartitions;
165
166	/* establish the actual sizes of the nasid masks */
167	if (rp->SAL_version == 1) {
168		/* SAL_version 1 didn't set the nasids_size field */
169		rp->SAL_nasids_size = 128;
170	}
171	xpc_nasid_mask_nbytes = rp->SAL_nasids_size;
172	xpc_nasid_mask_nlongs = BITS_TO_LONGS(rp->SAL_nasids_size *
173					      BITS_PER_BYTE);
174
175	/* setup the pointers to the various items in the reserved page */
176	xpc_part_nasids = XPC_RP_PART_NASIDS(rp);
177	xpc_mach_nasids = XPC_RP_MACH_NASIDS(rp);
178
179	ret = xpc_arch_ops.setup_rsvd_page(rp);
180	if (ret != 0)
181		return ret;
182
183	/*
184	 * Set timestamp of when reserved page was setup by XPC.
185	 * This signifies to the remote partition that our reserved
186	 * page is initialized.
187	 */
188	new_ts_jiffies = jiffies;
189	if (new_ts_jiffies == 0 || new_ts_jiffies == rp->ts_jiffies)
190		new_ts_jiffies++;
191	rp->ts_jiffies = new_ts_jiffies;
192
193	xpc_rsvd_page = rp;
194	return 0;
195}
196
197void
198xpc_teardown_rsvd_page(void)
199{
200	/* a zero timestamp indicates our rsvd page is not initialized */
201	xpc_rsvd_page->ts_jiffies = 0;
202}
203
204/*
205 * Get a copy of a portion of the remote partition's rsvd page.
206 *
207 * remote_rp points to a buffer that is cacheline aligned for BTE copies and
208 * is large enough to contain a copy of their reserved page header and
209 * part_nasids mask.
210 */
211enum xp_retval
212xpc_get_remote_rp(int nasid, unsigned long *discovered_nasids,
213		  struct xpc_rsvd_page *remote_rp, unsigned long *remote_rp_pa)
214{
215	int l;
216	enum xp_retval ret;
217
218	/* get the reserved page's physical address */
219
220	*remote_rp_pa = xpc_get_rsvd_page_pa(nasid);
221	if (*remote_rp_pa == 0)
222		return xpNoRsvdPageAddr;
223
224	/* pull over the reserved page header and part_nasids mask */
225	ret = xp_remote_memcpy(xp_pa(remote_rp), *remote_rp_pa,
226			       XPC_RP_HEADER_SIZE + xpc_nasid_mask_nbytes);
227	if (ret != xpSuccess)
228		return ret;
229
230	if (discovered_nasids != NULL) {
231		unsigned long *remote_part_nasids =
232		    XPC_RP_PART_NASIDS(remote_rp);
233
234		for (l = 0; l < xpc_nasid_mask_nlongs; l++)
235			discovered_nasids[l] |= remote_part_nasids[l];
236	}
237
238	/* zero timestamp indicates the reserved page has not been setup */
239	if (remote_rp->ts_jiffies == 0)
240		return xpRsvdPageNotSet;
241
242	if (XPC_VERSION_MAJOR(remote_rp->version) !=
243	    XPC_VERSION_MAJOR(XPC_RP_VERSION)) {
244		return xpBadVersion;
245	}
246
247	/* check that both remote and local partids are valid for each side */
248	if (remote_rp->SAL_partid < 0 ||
249	    remote_rp->SAL_partid >= xp_max_npartitions ||
250	    remote_rp->max_npartitions <= xp_partition_id) {
251		return xpInvalidPartid;
252	}
253
254	if (remote_rp->SAL_partid == xp_partition_id)
255		return xpLocalPartid;
256
257	return xpSuccess;
258}
259
260/*
261 * See if the other side has responded to a partition deactivate request
262 * from us. Though we requested the remote partition to deactivate with regard
263 * to us, we really only need to wait for the other side to disengage from us.
264 */
265static int __xpc_partition_disengaged(struct xpc_partition *part,
266				      bool from_timer)
267{
268	short partid = XPC_PARTID(part);
269	int disengaged;
270
271	disengaged = !xpc_arch_ops.partition_engaged(partid);
272	if (part->disengage_timeout) {
273		if (!disengaged) {
274			if (time_is_after_jiffies(part->disengage_timeout)) {
275				/* timelimit hasn't been reached yet */
276				return 0;
277			}
278
279			/*
280			 * Other side hasn't responded to our deactivate
281			 * request in a timely fashion, so assume it's dead.
282			 */
283
284			dev_info(xpc_part, "deactivate request to remote "
285				 "partition %d timed out\n", partid);
286			xpc_disengage_timedout = 1;
287			xpc_arch_ops.assume_partition_disengaged(partid);
288			disengaged = 1;
289		}
290		part->disengage_timeout = 0;
291
292		/* Cancel the timer function if not called from it */
293		if (!from_timer)
294			del_timer_sync(&part->disengage_timer);
295
296		DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING &&
297			part->act_state != XPC_P_AS_INACTIVE);
298		if (part->act_state != XPC_P_AS_INACTIVE)
299			xpc_wakeup_channel_mgr(part);
300
301		xpc_arch_ops.cancel_partition_deactivation_request(part);
302	}
303	return disengaged;
304}
305
306int xpc_partition_disengaged(struct xpc_partition *part)
307{
308	return __xpc_partition_disengaged(part, false);
309}
310
311int xpc_partition_disengaged_from_timer(struct xpc_partition *part)
312{
313	return __xpc_partition_disengaged(part, true);
314}
315
316/*
317 * Mark specified partition as active.
318 */
319enum xp_retval
320xpc_mark_partition_active(struct xpc_partition *part)
321{
322	unsigned long irq_flags;
323	enum xp_retval ret;
324
325	dev_dbg(xpc_part, "setting partition %d to ACTIVE\n", XPC_PARTID(part));
326
327	spin_lock_irqsave(&part->act_lock, irq_flags);
328	if (part->act_state == XPC_P_AS_ACTIVATING) {
329		part->act_state = XPC_P_AS_ACTIVE;
330		ret = xpSuccess;
331	} else {
332		DBUG_ON(part->reason == xpSuccess);
333		ret = part->reason;
334	}
335	spin_unlock_irqrestore(&part->act_lock, irq_flags);
336
337	return ret;
338}
339
340/*
341 * Start the process of deactivating the specified partition.
342 */
343void
344xpc_deactivate_partition(const int line, struct xpc_partition *part,
345			 enum xp_retval reason)
346{
347	unsigned long irq_flags;
348
349	spin_lock_irqsave(&part->act_lock, irq_flags);
350
351	if (part->act_state == XPC_P_AS_INACTIVE) {
352		XPC_SET_REASON(part, reason, line);
353		spin_unlock_irqrestore(&part->act_lock, irq_flags);
354		if (reason == xpReactivating) {
355			/* we interrupt ourselves to reactivate partition */
356			xpc_arch_ops.request_partition_reactivation(part);
357		}
358		return;
359	}
360	if (part->act_state == XPC_P_AS_DEACTIVATING) {
361		if ((part->reason == xpUnloading && reason != xpUnloading) ||
362		    reason == xpReactivating) {
363			XPC_SET_REASON(part, reason, line);
364		}
365		spin_unlock_irqrestore(&part->act_lock, irq_flags);
366		return;
367	}
368
369	part->act_state = XPC_P_AS_DEACTIVATING;
370	XPC_SET_REASON(part, reason, line);
371
372	spin_unlock_irqrestore(&part->act_lock, irq_flags);
373
374	/* ask remote partition to deactivate with regard to us */
375	xpc_arch_ops.request_partition_deactivation(part);
376
377	/* set a timelimit on the disengage phase of the deactivation request */
378	part->disengage_timeout = jiffies + (xpc_disengage_timelimit * HZ);
379	part->disengage_timer.expires = part->disengage_timeout;
380	add_timer(&part->disengage_timer);
381
382	dev_dbg(xpc_part, "bringing partition %d down, reason = %d\n",
383		XPC_PARTID(part), reason);
384
385	xpc_partition_going_down(part, reason);
386}
387
388/*
389 * Mark specified partition as inactive.
390 */
391void
392xpc_mark_partition_inactive(struct xpc_partition *part)
393{
394	unsigned long irq_flags;
395
396	dev_dbg(xpc_part, "setting partition %d to INACTIVE\n",
397		XPC_PARTID(part));
398
399	spin_lock_irqsave(&part->act_lock, irq_flags);
400	part->act_state = XPC_P_AS_INACTIVE;
401	spin_unlock_irqrestore(&part->act_lock, irq_flags);
402	part->remote_rp_pa = 0;
403}
404
405/*
406 * SAL has provided a partition and machine mask.  The partition mask
407 * contains a bit for each even nasid in our partition.  The machine
408 * mask contains a bit for each even nasid in the entire machine.
409 *
410 * Using those two bit arrays, we can determine which nasids are
411 * known in the machine.  Each should also have a reserved page
412 * initialized if they are available for partitioning.
413 */
414void
415xpc_discovery(void)
416{
417	void *remote_rp_base;
418	struct xpc_rsvd_page *remote_rp;
419	unsigned long remote_rp_pa;
420	int region;
421	int region_size;
422	int max_regions;
423	int nasid;
424	unsigned long *discovered_nasids;
425	enum xp_retval ret;
426
427	remote_rp = xpc_kmalloc_cacheline_aligned(XPC_RP_HEADER_SIZE +
428						  xpc_nasid_mask_nbytes,
429						  GFP_KERNEL, &remote_rp_base);
430	if (remote_rp == NULL)
431		return;
432
433	discovered_nasids = kcalloc(xpc_nasid_mask_nlongs, sizeof(long),
434				    GFP_KERNEL);
435	if (discovered_nasids == NULL) {
436		kfree(remote_rp_base);
437		return;
438	}
439
440	/*
441	 * The term 'region' in this context refers to the minimum number of
442	 * nodes that can comprise an access protection grouping. The access
443	 * protection is in regards to memory, IOI and IPI.
444	 */
445	region_size = xp_region_size;
446
447	if (is_uv_system())
448		max_regions = 256;
449	else {
450		max_regions = 64;
451
452		switch (region_size) {
453		case 128:
454			max_regions *= 2;
455			fallthrough;
456		case 64:
457			max_regions *= 2;
458			fallthrough;
459		case 32:
460			max_regions *= 2;
461			region_size = 16;
462		}
463	}
464
465	for (region = 0; region < max_regions; region++) {
466
467		if (xpc_exiting)
468			break;
469
470		dev_dbg(xpc_part, "searching region %d\n", region);
471
472		for (nasid = (region * region_size * 2);
473		     nasid < ((region + 1) * region_size * 2); nasid += 2) {
474
475			if (xpc_exiting)
476				break;
477
478			dev_dbg(xpc_part, "checking nasid %d\n", nasid);
479
480			if (test_bit(nasid / 2, xpc_part_nasids)) {
481				dev_dbg(xpc_part, "PROM indicates Nasid %d is "
482					"part of the local partition; skipping "
483					"region\n", nasid);
484				break;
485			}
486
487			if (!(test_bit(nasid / 2, xpc_mach_nasids))) {
488				dev_dbg(xpc_part, "PROM indicates Nasid %d was "
489					"not on Numa-Link network at reset\n",
490					nasid);
491				continue;
492			}
493
494			if (test_bit(nasid / 2, discovered_nasids)) {
495				dev_dbg(xpc_part, "Nasid %d is part of a "
496					"partition which was previously "
497					"discovered\n", nasid);
498				continue;
499			}
500
501			/* pull over the rsvd page header & part_nasids mask */
502
503			ret = xpc_get_remote_rp(nasid, discovered_nasids,
504						remote_rp, &remote_rp_pa);
505			if (ret != xpSuccess) {
506				dev_dbg(xpc_part, "unable to get reserved page "
507					"from nasid %d, reason=%d\n", nasid,
508					ret);
509
510				if (ret == xpLocalPartid)
511					break;
512
513				continue;
514			}
515
516			xpc_arch_ops.request_partition_activation(remote_rp,
517							 remote_rp_pa, nasid);
518		}
519	}
520
521	kfree(discovered_nasids);
522	kfree(remote_rp_base);
523}
524
525/*
526 * Given a partid, get the nasids owned by that partition from the
527 * remote partition's reserved page.
528 */
529enum xp_retval
530xpc_initiate_partid_to_nasids(short partid, void *nasid_mask)
531{
532	struct xpc_partition *part;
533	unsigned long part_nasid_pa;
534
535	part = &xpc_partitions[partid];
536	if (part->remote_rp_pa == 0)
537		return xpPartitionDown;
538
539	memset(nasid_mask, 0, xpc_nasid_mask_nbytes);
540
541	part_nasid_pa = (unsigned long)XPC_RP_PART_NASIDS(part->remote_rp_pa);
542
543	return xp_remote_memcpy(xp_pa(nasid_mask), part_nasid_pa,
544				xpc_nasid_mask_nbytes);
545}
546