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 * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
7 */
8
9/*
10 * Cross Partition Communication (XPC) partition support.
11 *
12 *	This is the part of XPC that detects the presence/absence of
13 *	other partitions. It provides a heartbeat and monitors the
14 *	heartbeats of other partitions.
15 *
16 */
17
18#include <linux/device.h>
19#include <linux/hardirq.h>
20#include <linux/slab.h>
21#include "xpc.h"
22#include <asm/uv/uv_hub.h>
23
24/* XPC is exiting flag */
25int xpc_exiting;
26
27/* this partition's reserved page pointers */
28struct xpc_rsvd_page *xpc_rsvd_page;
29static unsigned long *xpc_part_nasids;
30unsigned long *xpc_mach_nasids;
31
32static int xpc_nasid_mask_nbytes;	/* #of bytes in nasid mask */
33int xpc_nasid_mask_nlongs;	/* #of longs in nasid mask */
34
35struct xpc_partition *xpc_partitions;
36
37/*
38 * Guarantee that the kmalloc'd memory is cacheline aligned.
39 */
40void *
41xpc_kmalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
42{
43	/* see if kmalloc will give us cachline aligned memory by default */
44	*base = kmalloc(size, flags);
45	if (*base == NULL)
46		return NULL;
47
48	if ((u64)*base == L1_CACHE_ALIGN((u64)*base))
49		return *base;
50
51	kfree(*base);
52
53	/* nope, we'll have to do it ourselves */
54	*base = kmalloc(size + L1_CACHE_BYTES, flags);
55	if (*base == NULL)
56		return NULL;
57
58	return (void *)L1_CACHE_ALIGN((u64)*base);
59}
60
61/*
62 * Given a nasid, get the physical address of the  partition's reserved page
63 * for that nasid. This function returns 0 on any error.
64 */
65static unsigned long
66xpc_get_rsvd_page_pa(int nasid)
67{
68	enum xp_retval ret;
69	u64 cookie = 0;
70	unsigned long rp_pa = nasid;	/* seed with nasid */
71	size_t len = 0;
72	size_t buf_len = 0;
73	void *buf = buf;
74	void *buf_base = NULL;
75	enum xp_retval (*get_partition_rsvd_page_pa)
76		(void *, u64 *, unsigned long *, size_t *) =
77		xpc_arch_ops.get_partition_rsvd_page_pa;
78
79	while (1) {
80
81		/* !!! rp_pa will need to be _gpa on UV.
82		 * ??? So do we save it into the architecture specific parts
83		 * ??? of the xpc_partition structure? Do we rename this
84		 * ??? function or have two versions? Rename rp_pa for UV to
85		 * ??? rp_gpa?
86		 */
87		ret = get_partition_rsvd_page_pa(buf, &cookie, &rp_pa, &len);
88
89		dev_dbg(xpc_part, "SAL returned with ret=%d, cookie=0x%016lx, "
90			"address=0x%016lx, len=0x%016lx\n", ret,
91			(unsigned long)cookie, rp_pa, len);
92
93		if (ret != xpNeedMoreInfo)
94			break;
95
96		/* !!! L1_CACHE_ALIGN() is only a sn2-bte_copy requirement */
97		if (is_shub())
98			len = L1_CACHE_ALIGN(len);
99
100		if (len > buf_len) {
101			if (buf_base != NULL)
102				kfree(buf_base);
103			buf_len = L1_CACHE_ALIGN(len);
104			buf = xpc_kmalloc_cacheline_aligned(buf_len, GFP_KERNEL,
105							    &buf_base);
106			if (buf_base == NULL) {
107				dev_err(xpc_part, "unable to kmalloc "
108					"len=0x%016lx\n", buf_len);
109				ret = xpNoMemory;
110				break;
111			}
112		}
113
114		ret = xp_remote_memcpy(xp_pa(buf), rp_pa, len);
115		if (ret != xpSuccess) {
116			dev_dbg(xpc_part, "xp_remote_memcpy failed %d\n", ret);
117			break;
118		}
119	}
120
121	kfree(buf_base);
122
123	if (ret != xpSuccess)
124		rp_pa = 0;
125
126	dev_dbg(xpc_part, "reserved page at phys address 0x%016lx\n", rp_pa);
127	return rp_pa;
128}
129
130/*
131 * Fill the partition reserved page with the information needed by
132 * other partitions to discover we are alive and establish initial
133 * communications.
134 */
135int
136xpc_setup_rsvd_page(void)
137{
138	int ret;
139	struct xpc_rsvd_page *rp;
140	unsigned long rp_pa;
141	unsigned long new_ts_jiffies;
142
143	/* get the local reserved page's address */
144
145	preempt_disable();
146	rp_pa = xpc_get_rsvd_page_pa(xp_cpu_to_nasid(smp_processor_id()));
147	preempt_enable();
148	if (rp_pa == 0) {
149		dev_err(xpc_part, "SAL failed to locate the reserved page\n");
150		return -ESRCH;
151	}
152	rp = (struct xpc_rsvd_page *)__va(xp_socket_pa(rp_pa));
153
154	if (rp->SAL_version < 3) {
155		/* SAL_versions < 3 had a SAL_partid defined as a u8 */
156		rp->SAL_partid &= 0xff;
157	}
158	BUG_ON(rp->SAL_partid != xp_partition_id);
159
160	if (rp->SAL_partid < 0 || rp->SAL_partid >= xp_max_npartitions) {
161		dev_err(xpc_part, "the reserved page's partid of %d is outside "
162			"supported range (< 0 || >= %d)\n", rp->SAL_partid,
163			xp_max_npartitions);
164		return -EINVAL;
165	}
166
167	rp->version = XPC_RP_VERSION;
168	rp->max_npartitions = xp_max_npartitions;
169
170	/* establish the actual sizes of the nasid masks */
171	if (rp->SAL_version == 1) {
172		/* SAL_version 1 didn't set the nasids_size field */
173		rp->SAL_nasids_size = 128;
174	}
175	xpc_nasid_mask_nbytes = rp->SAL_nasids_size;
176	xpc_nasid_mask_nlongs = BITS_TO_LONGS(rp->SAL_nasids_size *
177					      BITS_PER_BYTE);
178
179	/* setup the pointers to the various items in the reserved page */
180	xpc_part_nasids = XPC_RP_PART_NASIDS(rp);
181	xpc_mach_nasids = XPC_RP_MACH_NASIDS(rp);
182
183	ret = xpc_arch_ops.setup_rsvd_page(rp);
184	if (ret != 0)
185		return ret;
186
187	/*
188	 * Set timestamp of when reserved page was setup by XPC.
189	 * This signifies to the remote partition that our reserved
190	 * page is initialized.
191	 */
192	new_ts_jiffies = jiffies;
193	if (new_ts_jiffies == 0 || new_ts_jiffies == rp->ts_jiffies)
194		new_ts_jiffies++;
195	rp->ts_jiffies = new_ts_jiffies;
196
197	xpc_rsvd_page = rp;
198	return 0;
199}
200
201void
202xpc_teardown_rsvd_page(void)
203{
204	/* a zero timestamp indicates our rsvd page is not initialized */
205	xpc_rsvd_page->ts_jiffies = 0;
206}
207
208/*
209 * Get a copy of a portion of the remote partition's rsvd page.
210 *
211 * remote_rp points to a buffer that is cacheline aligned for BTE copies and
212 * is large enough to contain a copy of their reserved page header and
213 * part_nasids mask.
214 */
215enum xp_retval
216xpc_get_remote_rp(int nasid, unsigned long *discovered_nasids,
217		  struct xpc_rsvd_page *remote_rp, unsigned long *remote_rp_pa)
218{
219	int l;
220	enum xp_retval ret;
221
222	/* get the reserved page's physical address */
223
224	*remote_rp_pa = xpc_get_rsvd_page_pa(nasid);
225	if (*remote_rp_pa == 0)
226		return xpNoRsvdPageAddr;
227
228	/* pull over the reserved page header and part_nasids mask */
229	ret = xp_remote_memcpy(xp_pa(remote_rp), *remote_rp_pa,
230			       XPC_RP_HEADER_SIZE + xpc_nasid_mask_nbytes);
231	if (ret != xpSuccess)
232		return ret;
233
234	if (discovered_nasids != NULL) {
235		unsigned long *remote_part_nasids =
236		    XPC_RP_PART_NASIDS(remote_rp);
237
238		for (l = 0; l < xpc_nasid_mask_nlongs; l++)
239			discovered_nasids[l] |= remote_part_nasids[l];
240	}
241
242	/* zero timestamp indicates the reserved page has not been setup */
243	if (remote_rp->ts_jiffies == 0)
244		return xpRsvdPageNotSet;
245
246	if (XPC_VERSION_MAJOR(remote_rp->version) !=
247	    XPC_VERSION_MAJOR(XPC_RP_VERSION)) {
248		return xpBadVersion;
249	}
250
251	/* check that both remote and local partids are valid for each side */
252	if (remote_rp->SAL_partid < 0 ||
253	    remote_rp->SAL_partid >= xp_max_npartitions ||
254	    remote_rp->max_npartitions <= xp_partition_id) {
255		return xpInvalidPartid;
256	}
257
258	if (remote_rp->SAL_partid == xp_partition_id)
259		return xpLocalPartid;
260
261	return xpSuccess;
262}
263
264/*
265 * See if the other side has responded to a partition deactivate request
266 * from us. Though we requested the remote partition to deactivate with regard
267 * to us, we really only need to wait for the other side to disengage from us.
268 */
269int
270xpc_partition_disengaged(struct xpc_partition *part)
271{
272	short partid = XPC_PARTID(part);
273	int disengaged;
274
275	disengaged = !xpc_arch_ops.partition_engaged(partid);
276	if (part->disengage_timeout) {
277		if (!disengaged) {
278			if (time_is_after_jiffies(part->disengage_timeout)) {
279				/* timelimit hasn't been reached yet */
280				return 0;
281			}
282
283			/*
284			 * Other side hasn't responded to our deactivate
285			 * request in a timely fashion, so assume it's dead.
286			 */
287
288			dev_info(xpc_part, "deactivate request to remote "
289				 "partition %d timed out\n", partid);
290			xpc_disengage_timedout = 1;
291			xpc_arch_ops.assume_partition_disengaged(partid);
292			disengaged = 1;
293		}
294		part->disengage_timeout = 0;
295
296		/* cancel the timer function, provided it's not us */
297		if (!in_interrupt())
298			del_singleshot_timer_sync(&part->disengage_timer);
299
300		DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING &&
301			part->act_state != XPC_P_AS_INACTIVE);
302		if (part->act_state != XPC_P_AS_INACTIVE)
303			xpc_wakeup_channel_mgr(part);
304
305		xpc_arch_ops.cancel_partition_deactivation_request(part);
306	}
307	return disengaged;
308}
309
310/*
311 * Mark specified partition as active.
312 */
313enum xp_retval
314xpc_mark_partition_active(struct xpc_partition *part)
315{
316	unsigned long irq_flags;
317	enum xp_retval ret;
318
319	dev_dbg(xpc_part, "setting partition %d to ACTIVE\n", XPC_PARTID(part));
320
321	spin_lock_irqsave(&part->act_lock, irq_flags);
322	if (part->act_state == XPC_P_AS_ACTIVATING) {
323		part->act_state = XPC_P_AS_ACTIVE;
324		ret = xpSuccess;
325	} else {
326		DBUG_ON(part->reason == xpSuccess);
327		ret = part->reason;
328	}
329	spin_unlock_irqrestore(&part->act_lock, irq_flags);
330
331	return ret;
332}
333
334/*
335 * Start the process of deactivating the specified partition.
336 */
337void
338xpc_deactivate_partition(const int line, struct xpc_partition *part,
339			 enum xp_retval reason)
340{
341	unsigned long irq_flags;
342
343	spin_lock_irqsave(&part->act_lock, irq_flags);
344
345	if (part->act_state == XPC_P_AS_INACTIVE) {
346		XPC_SET_REASON(part, reason, line);
347		spin_unlock_irqrestore(&part->act_lock, irq_flags);
348		if (reason == xpReactivating) {
349			/* we interrupt ourselves to reactivate partition */
350			xpc_arch_ops.request_partition_reactivation(part);
351		}
352		return;
353	}
354	if (part->act_state == XPC_P_AS_DEACTIVATING) {
355		if ((part->reason == xpUnloading && reason != xpUnloading) ||
356		    reason == xpReactivating) {
357			XPC_SET_REASON(part, reason, line);
358		}
359		spin_unlock_irqrestore(&part->act_lock, irq_flags);
360		return;
361	}
362
363	part->act_state = XPC_P_AS_DEACTIVATING;
364	XPC_SET_REASON(part, reason, line);
365
366	spin_unlock_irqrestore(&part->act_lock, irq_flags);
367
368	/* ask remote partition to deactivate with regard to us */
369	xpc_arch_ops.request_partition_deactivation(part);
370
371	/* set a timelimit on the disengage phase of the deactivation request */
372	part->disengage_timeout = jiffies + (xpc_disengage_timelimit * HZ);
373	part->disengage_timer.expires = part->disengage_timeout;
374	add_timer(&part->disengage_timer);
375
376	dev_dbg(xpc_part, "bringing partition %d down, reason = %d\n",
377		XPC_PARTID(part), reason);
378
379	xpc_partition_going_down(part, reason);
380}
381
382/*
383 * Mark specified partition as inactive.
384 */
385void
386xpc_mark_partition_inactive(struct xpc_partition *part)
387{
388	unsigned long irq_flags;
389
390	dev_dbg(xpc_part, "setting partition %d to INACTIVE\n",
391		XPC_PARTID(part));
392
393	spin_lock_irqsave(&part->act_lock, irq_flags);
394	part->act_state = XPC_P_AS_INACTIVE;
395	spin_unlock_irqrestore(&part->act_lock, irq_flags);
396	part->remote_rp_pa = 0;
397}
398
399/*
400 * SAL has provided a partition and machine mask.  The partition mask
401 * contains a bit for each even nasid in our partition.  The machine
402 * mask contains a bit for each even nasid in the entire machine.
403 *
404 * Using those two bit arrays, we can determine which nasids are
405 * known in the machine.  Each should also have a reserved page
406 * initialized if they are available for partitioning.
407 */
408void
409xpc_discovery(void)
410{
411	void *remote_rp_base;
412	struct xpc_rsvd_page *remote_rp;
413	unsigned long remote_rp_pa;
414	int region;
415	int region_size;
416	int max_regions;
417	int nasid;
418	struct xpc_rsvd_page *rp;
419	unsigned long *discovered_nasids;
420	enum xp_retval ret;
421
422	remote_rp = xpc_kmalloc_cacheline_aligned(XPC_RP_HEADER_SIZE +
423						  xpc_nasid_mask_nbytes,
424						  GFP_KERNEL, &remote_rp_base);
425	if (remote_rp == NULL)
426		return;
427
428	discovered_nasids = kzalloc(sizeof(long) * xpc_nasid_mask_nlongs,
429				    GFP_KERNEL);
430	if (discovered_nasids == NULL) {
431		kfree(remote_rp_base);
432		return;
433	}
434
435	rp = (struct xpc_rsvd_page *)xpc_rsvd_page;
436
437	/*
438	 * The term 'region' in this context refers to the minimum number of
439	 * nodes that can comprise an access protection grouping. The access
440	 * protection is in regards to memory, IOI and IPI.
441	 */
442	region_size = xp_region_size;
443
444	if (is_uv())
445		max_regions = 256;
446	else {
447		max_regions = 64;
448
449		switch (region_size) {
450		case 128:
451			max_regions *= 2;
452		case 64:
453			max_regions *= 2;
454		case 32:
455			max_regions *= 2;
456			region_size = 16;
457			DBUG_ON(!is_shub2());
458		}
459	}
460
461	for (region = 0; region < max_regions; region++) {
462
463		if (xpc_exiting)
464			break;
465
466		dev_dbg(xpc_part, "searching region %d\n", region);
467
468		for (nasid = (region * region_size * 2);
469		     nasid < ((region + 1) * region_size * 2); nasid += 2) {
470
471			if (xpc_exiting)
472				break;
473
474			dev_dbg(xpc_part, "checking nasid %d\n", nasid);
475
476			if (test_bit(nasid / 2, xpc_part_nasids)) {
477				dev_dbg(xpc_part, "PROM indicates Nasid %d is "
478					"part of the local partition; skipping "
479					"region\n", nasid);
480				break;
481			}
482
483			if (!(test_bit(nasid / 2, xpc_mach_nasids))) {
484				dev_dbg(xpc_part, "PROM indicates Nasid %d was "
485					"not on Numa-Link network at reset\n",
486					nasid);
487				continue;
488			}
489
490			if (test_bit(nasid / 2, discovered_nasids)) {
491				dev_dbg(xpc_part, "Nasid %d is part of a "
492					"partition which was previously "
493					"discovered\n", nasid);
494				continue;
495			}
496
497			/* pull over the rsvd page header & part_nasids mask */
498
499			ret = xpc_get_remote_rp(nasid, discovered_nasids,
500						remote_rp, &remote_rp_pa);
501			if (ret != xpSuccess) {
502				dev_dbg(xpc_part, "unable to get reserved page "
503					"from nasid %d, reason=%d\n", nasid,
504					ret);
505
506				if (ret == xpLocalPartid)
507					break;
508
509				continue;
510			}
511
512			xpc_arch_ops.request_partition_activation(remote_rp,
513							 remote_rp_pa, nasid);
514		}
515	}
516
517	kfree(discovered_nasids);
518	kfree(remote_rp_base);
519}
520
521/*
522 * Given a partid, get the nasids owned by that partition from the
523 * remote partition's reserved page.
524 */
525enum xp_retval
526xpc_initiate_partid_to_nasids(short partid, void *nasid_mask)
527{
528	struct xpc_partition *part;
529	unsigned long part_nasid_pa;
530
531	part = &xpc_partitions[partid];
532	if (part->remote_rp_pa == 0)
533		return xpPartitionDown;
534
535	memset(nasid_mask, 0, xpc_nasid_mask_nbytes);
536
537	part_nasid_pa = (unsigned long)XPC_RP_PART_NASIDS(part->remote_rp_pa);
538
539	return xp_remote_memcpy(xp_pa(nasid_mask), part_nasid_pa,
540				xpc_nasid_mask_nbytes);
541}
542