1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * SN Platform GRU Driver
4  *
5  *              KERNEL SERVICES THAT USE THE GRU
6  *
7  *  Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <linux/mm.h>
14 #include <linux/spinlock.h>
15 #include <linux/device.h>
16 #include <linux/miscdevice.h>
17 #include <linux/proc_fs.h>
18 #include <linux/interrupt.h>
19 #include <linux/sync_core.h>
20 #include <linux/uaccess.h>
21 #include <linux/delay.h>
22 #include <linux/export.h>
23 #include <asm/io_apic.h>
24 #include "gru.h"
25 #include "grulib.h"
26 #include "grutables.h"
27 #include "grukservices.h"
28 #include "gru_instructions.h"
29 #include <asm/uv/uv_hub.h>
30 
31 /*
32  * Kernel GRU Usage
33  *
34  * The following is an interim algorithm for management of kernel GRU
35  * resources. This will likely be replaced when we better understand the
36  * kernel/user requirements.
37  *
38  * Blade percpu resources reserved for kernel use. These resources are
39  * reserved whenever the the kernel context for the blade is loaded. Note
40  * that the kernel context is not guaranteed to be always available. It is
41  * loaded on demand & can be stolen by a user if the user demand exceeds the
42  * kernel demand. The kernel can always reload the kernel context but
43  * a SLEEP may be required!!!.
44  *
45  * Async Overview:
46  *
47  * 	Each blade has one "kernel context" that owns GRU kernel resources
48  * 	located on the blade. Kernel drivers use GRU resources in this context
49  * 	for sending messages, zeroing memory, etc.
50  *
51  * 	The kernel context is dynamically loaded on demand. If it is not in
52  * 	use by the kernel, the kernel context can be unloaded & given to a user.
53  * 	The kernel context will be reloaded when needed. This may require that
54  * 	a context be stolen from a user.
55  * 		NOTE: frequent unloading/reloading of the kernel context is
56  * 		expensive. We are depending on batch schedulers, cpusets, sane
57  * 		drivers or some other mechanism to prevent the need for frequent
58  *	 	stealing/reloading.
59  *
60  * 	The kernel context consists of two parts:
61  * 		- 1 CB & a few DSRs that are reserved for each cpu on the blade.
62  * 		  Each cpu has it's own private resources & does not share them
63  * 		  with other cpus. These resources are used serially, ie,
64  * 		  locked, used & unlocked  on each call to a function in
65  * 		  grukservices.
66  * 		  	(Now that we have dynamic loading of kernel contexts, I
67  * 		  	 may rethink this & allow sharing between cpus....)
68  *
69  *		- Additional resources can be reserved long term & used directly
70  *		  by UV drivers located in the kernel. Drivers using these GRU
71  *		  resources can use asynchronous GRU instructions that send
72  *		  interrupts on completion.
73  *		  	- these resources must be explicitly locked/unlocked
74  *		  	- locked resources prevent (obviously) the kernel
75  *		  	  context from being unloaded.
76  *			- drivers using these resource directly issue their own
77  *			  GRU instruction and must wait/check completion.
78  *
79  * 		  When these resources are reserved, the caller can optionally
80  * 		  associate a wait_queue with the resources and use asynchronous
81  * 		  GRU instructions. When an async GRU instruction completes, the
82  * 		  driver will do a wakeup on the event.
83  *
84  */
85 
86 
87 #define ASYNC_HAN_TO_BID(h)	((h) - 1)
88 #define ASYNC_BID_TO_HAN(b)	((b) + 1)
89 #define ASYNC_HAN_TO_BS(h)	gru_base[ASYNC_HAN_TO_BID(h)]
90 
91 #define GRU_NUM_KERNEL_CBR	1
92 #define GRU_NUM_KERNEL_DSR_BYTES 256
93 #define GRU_NUM_KERNEL_DSR_CL	(GRU_NUM_KERNEL_DSR_BYTES /		\
94 					GRU_CACHE_LINE_BYTES)
95 
96 /* GRU instruction attributes for all instructions */
97 #define IMA			IMA_CB_DELAY
98 
99 /* GRU cacheline size is always 64 bytes - even on arches with 128 byte lines */
100 #define __gru_cacheline_aligned__                               \
101 	__attribute__((__aligned__(GRU_CACHE_LINE_BYTES)))
102 
103 #define MAGIC	0x1234567887654321UL
104 
105 /* Default retry count for GRU errors on kernel instructions */
106 #define EXCEPTION_RETRY_LIMIT	3
107 
108 /* Status of message queue sections */
109 #define MQS_EMPTY		0
110 #define MQS_FULL		1
111 #define MQS_NOOP		2
112 
113 /*----------------- RESOURCE MANAGEMENT -------------------------------------*/
114 /* optimized for x86_64 */
115 struct message_queue {
116 	union gru_mesqhead	head __gru_cacheline_aligned__;	/* CL 0 */
117 	int			qlines;				/* DW 1 */
118 	long 			hstatus[2];
119 	void 			*next __gru_cacheline_aligned__;/* CL 1 */
120 	void 			*limit;
121 	void 			*start;
122 	void 			*start2;
123 	char			data ____cacheline_aligned;	/* CL 2 */
124 };
125 
126 /* First word in every message - used by mesq interface */
127 struct message_header {
128 	char	present;
129 	char	present2;
130 	char 	lines;
131 	char	fill;
132 };
133 
134 #define HSTATUS(mq, h)	((mq) + offsetof(struct message_queue, hstatus[h]))
135 
136 /*
137  * Reload the blade's kernel context into a GRU chiplet. Called holding
138  * the bs_kgts_sema for READ. Will steal user contexts if necessary.
139  */
140 static void gru_load_kernel_context(struct gru_blade_state *bs, int blade_id)
141 {
142 	struct gru_state *gru;
143 	struct gru_thread_state *kgts;
144 	void *vaddr;
145 	int ctxnum, ncpus;
146 
147 	up_read(&bs->bs_kgts_sema);
148 	down_write(&bs->bs_kgts_sema);
149 
150 	if (!bs->bs_kgts) {
151 		do {
152 			bs->bs_kgts = gru_alloc_gts(NULL, 0, 0, 0, 0, 0);
153 			if (!IS_ERR(bs->bs_kgts))
154 				break;
155 			msleep(1);
156 		} while (true);
157 		bs->bs_kgts->ts_user_blade_id = blade_id;
158 	}
159 	kgts = bs->bs_kgts;
160 
161 	if (!kgts->ts_gru) {
162 		STAT(load_kernel_context);
163 		ncpus = uv_blade_nr_possible_cpus(blade_id);
164 		kgts->ts_cbr_au_count = GRU_CB_COUNT_TO_AU(
165 			GRU_NUM_KERNEL_CBR * ncpus + bs->bs_async_cbrs);
166 		kgts->ts_dsr_au_count = GRU_DS_BYTES_TO_AU(
167 			GRU_NUM_KERNEL_DSR_BYTES * ncpus +
168 				bs->bs_async_dsr_bytes);
169 		while (!gru_assign_gru_context(kgts)) {
170 			msleep(1);
171 			gru_steal_context(kgts);
172 		}
173 		gru_load_context(kgts);
174 		gru = bs->bs_kgts->ts_gru;
175 		vaddr = gru->gs_gru_base_vaddr;
176 		ctxnum = kgts->ts_ctxnum;
177 		bs->kernel_cb = get_gseg_base_address_cb(vaddr, ctxnum, 0);
178 		bs->kernel_dsr = get_gseg_base_address_ds(vaddr, ctxnum, 0);
179 	}
180 	downgrade_write(&bs->bs_kgts_sema);
181 }
182 
183 /*
184  * Free all kernel contexts that are not currently in use.
185  *   Returns 0 if all freed, else number of inuse context.
186  */
187 static int gru_free_kernel_contexts(void)
188 {
189 	struct gru_blade_state *bs;
190 	struct gru_thread_state *kgts;
191 	int bid, ret = 0;
192 
193 	for (bid = 0; bid < GRU_MAX_BLADES; bid++) {
194 		bs = gru_base[bid];
195 		if (!bs)
196 			continue;
197 
198 		/* Ignore busy contexts. Don't want to block here.  */
199 		if (down_write_trylock(&bs->bs_kgts_sema)) {
200 			kgts = bs->bs_kgts;
201 			if (kgts && kgts->ts_gru)
202 				gru_unload_context(kgts, 0);
203 			bs->bs_kgts = NULL;
204 			up_write(&bs->bs_kgts_sema);
205 			kfree(kgts);
206 		} else {
207 			ret++;
208 		}
209 	}
210 	return ret;
211 }
212 
213 /*
214  * Lock & load the kernel context for the specified blade.
215  */
216 static struct gru_blade_state *gru_lock_kernel_context(int blade_id)
217 {
218 	struct gru_blade_state *bs;
219 	int bid;
220 
221 	STAT(lock_kernel_context);
222 again:
223 	bid = blade_id < 0 ? uv_numa_blade_id() : blade_id;
224 	bs = gru_base[bid];
225 
226 	/* Handle the case where migration occurred while waiting for the sema */
227 	down_read(&bs->bs_kgts_sema);
228 	if (blade_id < 0 && bid != uv_numa_blade_id()) {
229 		up_read(&bs->bs_kgts_sema);
230 		goto again;
231 	}
232 	if (!bs->bs_kgts || !bs->bs_kgts->ts_gru)
233 		gru_load_kernel_context(bs, bid);
234 	return bs;
235 
236 }
237 
238 /*
239  * Unlock the kernel context for the specified blade. Context is not
240  * unloaded but may be stolen before next use.
241  */
242 static void gru_unlock_kernel_context(int blade_id)
243 {
244 	struct gru_blade_state *bs;
245 
246 	bs = gru_base[blade_id];
247 	up_read(&bs->bs_kgts_sema);
248 	STAT(unlock_kernel_context);
249 }
250 
251 /*
252  * Reserve & get pointers to the DSR/CBRs reserved for the current cpu.
253  * 	- returns with preemption disabled
254  */
255 static int gru_get_cpu_resources(int dsr_bytes, void **cb, void **dsr)
256 {
257 	struct gru_blade_state *bs;
258 	int lcpu;
259 
260 	BUG_ON(dsr_bytes > GRU_NUM_KERNEL_DSR_BYTES);
261 	preempt_disable();
262 	bs = gru_lock_kernel_context(-1);
263 	lcpu = uv_blade_processor_id();
264 	*cb = bs->kernel_cb + lcpu * GRU_HANDLE_STRIDE;
265 	*dsr = bs->kernel_dsr + lcpu * GRU_NUM_KERNEL_DSR_BYTES;
266 	return 0;
267 }
268 
269 /*
270  * Free the current cpus reserved DSR/CBR resources.
271  */
272 static void gru_free_cpu_resources(void *cb, void *dsr)
273 {
274 	gru_unlock_kernel_context(uv_numa_blade_id());
275 	preempt_enable();
276 }
277 
278 /*
279  * Reserve GRU resources to be used asynchronously.
280  *   Note: currently supports only 1 reservation per blade.
281  *
282  * 	input:
283  * 		blade_id  - blade on which resources should be reserved
284  * 		cbrs	  - number of CBRs
285  * 		dsr_bytes - number of DSR bytes needed
286  *	output:
287  *		handle to identify resource
288  *		(0 = async resources already reserved)
289  */
290 unsigned long gru_reserve_async_resources(int blade_id, int cbrs, int dsr_bytes,
291 			struct completion *cmp)
292 {
293 	struct gru_blade_state *bs;
294 	struct gru_thread_state *kgts;
295 	int ret = 0;
296 
297 	bs = gru_base[blade_id];
298 
299 	down_write(&bs->bs_kgts_sema);
300 
301 	/* Verify no resources already reserved */
302 	if (bs->bs_async_dsr_bytes + bs->bs_async_cbrs)
303 		goto done;
304 	bs->bs_async_dsr_bytes = dsr_bytes;
305 	bs->bs_async_cbrs = cbrs;
306 	bs->bs_async_wq = cmp;
307 	kgts = bs->bs_kgts;
308 
309 	/* Resources changed. Unload context if already loaded */
310 	if (kgts && kgts->ts_gru)
311 		gru_unload_context(kgts, 0);
312 	ret = ASYNC_BID_TO_HAN(blade_id);
313 
314 done:
315 	up_write(&bs->bs_kgts_sema);
316 	return ret;
317 }
318 
319 /*
320  * Release async resources previously reserved.
321  *
322  *	input:
323  *		han - handle to identify resources
324  */
325 void gru_release_async_resources(unsigned long han)
326 {
327 	struct gru_blade_state *bs = ASYNC_HAN_TO_BS(han);
328 
329 	down_write(&bs->bs_kgts_sema);
330 	bs->bs_async_dsr_bytes = 0;
331 	bs->bs_async_cbrs = 0;
332 	bs->bs_async_wq = NULL;
333 	up_write(&bs->bs_kgts_sema);
334 }
335 
336 /*
337  * Wait for async GRU instructions to complete.
338  *
339  *	input:
340  *		han - handle to identify resources
341  */
342 void gru_wait_async_cbr(unsigned long han)
343 {
344 	struct gru_blade_state *bs = ASYNC_HAN_TO_BS(han);
345 
346 	wait_for_completion(bs->bs_async_wq);
347 	mb();
348 }
349 
350 /*
351  * Lock previous reserved async GRU resources
352  *
353  *	input:
354  *		han - handle to identify resources
355  *	output:
356  *		cb  - pointer to first CBR
357  *		dsr - pointer to first DSR
358  */
359 void gru_lock_async_resource(unsigned long han,  void **cb, void **dsr)
360 {
361 	struct gru_blade_state *bs = ASYNC_HAN_TO_BS(han);
362 	int blade_id = ASYNC_HAN_TO_BID(han);
363 	int ncpus;
364 
365 	gru_lock_kernel_context(blade_id);
366 	ncpus = uv_blade_nr_possible_cpus(blade_id);
367 	if (cb)
368 		*cb = bs->kernel_cb + ncpus * GRU_HANDLE_STRIDE;
369 	if (dsr)
370 		*dsr = bs->kernel_dsr + ncpus * GRU_NUM_KERNEL_DSR_BYTES;
371 }
372 
373 /*
374  * Unlock previous reserved async GRU resources
375  *
376  *	input:
377  *		han - handle to identify resources
378  */
379 void gru_unlock_async_resource(unsigned long han)
380 {
381 	int blade_id = ASYNC_HAN_TO_BID(han);
382 
383 	gru_unlock_kernel_context(blade_id);
384 }
385 
386 /*----------------------------------------------------------------------*/
387 int gru_get_cb_exception_detail(void *cb,
388 		struct control_block_extended_exc_detail *excdet)
389 {
390 	struct gru_control_block_extended *cbe;
391 	struct gru_thread_state *kgts = NULL;
392 	unsigned long off;
393 	int cbrnum, bid;
394 
395 	/*
396 	 * Locate kgts for cb. This algorithm is SLOW but
397 	 * this function is rarely called (ie., almost never).
398 	 * Performance does not matter.
399 	 */
400 	for_each_possible_blade(bid) {
401 		if (!gru_base[bid])
402 			break;
403 		kgts = gru_base[bid]->bs_kgts;
404 		if (!kgts || !kgts->ts_gru)
405 			continue;
406 		off = cb - kgts->ts_gru->gs_gru_base_vaddr;
407 		if (off < GRU_SIZE)
408 			break;
409 		kgts = NULL;
410 	}
411 	BUG_ON(!kgts);
412 	cbrnum = thread_cbr_number(kgts, get_cb_number(cb));
413 	cbe = get_cbe(GRUBASE(cb), cbrnum);
414 	gru_flush_cache(cbe);	/* CBE not coherent */
415 	sync_core();
416 	excdet->opc = cbe->opccpy;
417 	excdet->exopc = cbe->exopccpy;
418 	excdet->ecause = cbe->ecause;
419 	excdet->exceptdet0 = cbe->idef1upd;
420 	excdet->exceptdet1 = cbe->idef3upd;
421 	gru_flush_cache(cbe);
422 	return 0;
423 }
424 
425 static char *gru_get_cb_exception_detail_str(int ret, void *cb,
426 					     char *buf, int size)
427 {
428 	struct gru_control_block_status *gen = (void *)cb;
429 	struct control_block_extended_exc_detail excdet;
430 
431 	if (ret > 0 && gen->istatus == CBS_EXCEPTION) {
432 		gru_get_cb_exception_detail(cb, &excdet);
433 		snprintf(buf, size,
434 			"GRU:%d exception: cb %p, opc %d, exopc %d, ecause 0x%x,"
435 			"excdet0 0x%lx, excdet1 0x%x", smp_processor_id(),
436 			gen, excdet.opc, excdet.exopc, excdet.ecause,
437 			excdet.exceptdet0, excdet.exceptdet1);
438 	} else {
439 		snprintf(buf, size, "No exception");
440 	}
441 	return buf;
442 }
443 
444 static int gru_wait_idle_or_exception(struct gru_control_block_status *gen)
445 {
446 	while (gen->istatus >= CBS_ACTIVE) {
447 		cpu_relax();
448 		barrier();
449 	}
450 	return gen->istatus;
451 }
452 
453 static int gru_retry_exception(void *cb)
454 {
455 	struct gru_control_block_status *gen = (void *)cb;
456 	struct control_block_extended_exc_detail excdet;
457 	int retry = EXCEPTION_RETRY_LIMIT;
458 
459 	while (1)  {
460 		if (gru_wait_idle_or_exception(gen) == CBS_IDLE)
461 			return CBS_IDLE;
462 		if (gru_get_cb_message_queue_substatus(cb))
463 			return CBS_EXCEPTION;
464 		gru_get_cb_exception_detail(cb, &excdet);
465 		if ((excdet.ecause & ~EXCEPTION_RETRY_BITS) ||
466 				(excdet.cbrexecstatus & CBR_EXS_ABORT_OCC))
467 			break;
468 		if (retry-- == 0)
469 			break;
470 		gen->icmd = 1;
471 		gru_flush_cache(gen);
472 	}
473 	return CBS_EXCEPTION;
474 }
475 
476 int gru_check_status_proc(void *cb)
477 {
478 	struct gru_control_block_status *gen = (void *)cb;
479 	int ret;
480 
481 	ret = gen->istatus;
482 	if (ret == CBS_EXCEPTION)
483 		ret = gru_retry_exception(cb);
484 	rmb();
485 	return ret;
486 
487 }
488 
489 int gru_wait_proc(void *cb)
490 {
491 	struct gru_control_block_status *gen = (void *)cb;
492 	int ret;
493 
494 	ret = gru_wait_idle_or_exception(gen);
495 	if (ret == CBS_EXCEPTION)
496 		ret = gru_retry_exception(cb);
497 	rmb();
498 	return ret;
499 }
500 
501 static void gru_abort(int ret, void *cb, char *str)
502 {
503 	char buf[GRU_EXC_STR_SIZE];
504 
505 	panic("GRU FATAL ERROR: %s - %s\n", str,
506 	      gru_get_cb_exception_detail_str(ret, cb, buf, sizeof(buf)));
507 }
508 
509 void gru_wait_abort_proc(void *cb)
510 {
511 	int ret;
512 
513 	ret = gru_wait_proc(cb);
514 	if (ret)
515 		gru_abort(ret, cb, "gru_wait_abort");
516 }
517 
518 
519 /*------------------------------ MESSAGE QUEUES -----------------------------*/
520 
521 /* Internal status . These are NOT returned to the user. */
522 #define MQIE_AGAIN		-1	/* try again */
523 
524 
525 /*
526  * Save/restore the "present" flag that is in the second line of 2-line
527  * messages
528  */
529 static inline int get_present2(void *p)
530 {
531 	struct message_header *mhdr = p + GRU_CACHE_LINE_BYTES;
532 	return mhdr->present;
533 }
534 
535 static inline void restore_present2(void *p, int val)
536 {
537 	struct message_header *mhdr = p + GRU_CACHE_LINE_BYTES;
538 	mhdr->present = val;
539 }
540 
541 /*
542  * Create a message queue.
543  * 	qlines - message queue size in cache lines. Includes 2-line header.
544  */
545 int gru_create_message_queue(struct gru_message_queue_desc *mqd,
546 		void *p, unsigned int bytes, int nasid, int vector, int apicid)
547 {
548 	struct message_queue *mq = p;
549 	unsigned int qlines;
550 
551 	qlines = bytes / GRU_CACHE_LINE_BYTES - 2;
552 	memset(mq, 0, bytes);
553 	mq->start = &mq->data;
554 	mq->start2 = &mq->data + (qlines / 2 - 1) * GRU_CACHE_LINE_BYTES;
555 	mq->next = &mq->data;
556 	mq->limit = &mq->data + (qlines - 2) * GRU_CACHE_LINE_BYTES;
557 	mq->qlines = qlines;
558 	mq->hstatus[0] = 0;
559 	mq->hstatus[1] = 1;
560 	mq->head = gru_mesq_head(2, qlines / 2 + 1);
561 	mqd->mq = mq;
562 	mqd->mq_gpa = uv_gpa(mq);
563 	mqd->qlines = qlines;
564 	mqd->interrupt_pnode = nasid >> 1;
565 	mqd->interrupt_vector = vector;
566 	mqd->interrupt_apicid = apicid;
567 	return 0;
568 }
569 EXPORT_SYMBOL_GPL(gru_create_message_queue);
570 
571 /*
572  * Send a NOOP message to a message queue
573  * 	Returns:
574  * 		 0 - if queue is full after the send. This is the normal case
575  * 		     but various races can change this.
576  *		-1 - if mesq sent successfully but queue not full
577  *		>0 - unexpected error. MQE_xxx returned
578  */
579 static int send_noop_message(void *cb, struct gru_message_queue_desc *mqd,
580 				void *mesg)
581 {
582 	const struct message_header noop_header = {
583 					.present = MQS_NOOP, .lines = 1};
584 	unsigned long m;
585 	int substatus, ret;
586 	struct message_header save_mhdr, *mhdr = mesg;
587 
588 	STAT(mesq_noop);
589 	save_mhdr = *mhdr;
590 	*mhdr = noop_header;
591 	gru_mesq(cb, mqd->mq_gpa, gru_get_tri(mhdr), 1, IMA);
592 	ret = gru_wait(cb);
593 
594 	if (ret) {
595 		substatus = gru_get_cb_message_queue_substatus(cb);
596 		switch (substatus) {
597 		case CBSS_NO_ERROR:
598 			STAT(mesq_noop_unexpected_error);
599 			ret = MQE_UNEXPECTED_CB_ERR;
600 			break;
601 		case CBSS_LB_OVERFLOWED:
602 			STAT(mesq_noop_lb_overflow);
603 			ret = MQE_CONGESTION;
604 			break;
605 		case CBSS_QLIMIT_REACHED:
606 			STAT(mesq_noop_qlimit_reached);
607 			ret = 0;
608 			break;
609 		case CBSS_AMO_NACKED:
610 			STAT(mesq_noop_amo_nacked);
611 			ret = MQE_CONGESTION;
612 			break;
613 		case CBSS_PUT_NACKED:
614 			STAT(mesq_noop_put_nacked);
615 			m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
616 			gru_vstore(cb, m, gru_get_tri(mesg), XTYPE_CL, 1, 1,
617 						IMA);
618 			if (gru_wait(cb) == CBS_IDLE)
619 				ret = MQIE_AGAIN;
620 			else
621 				ret = MQE_UNEXPECTED_CB_ERR;
622 			break;
623 		case CBSS_PAGE_OVERFLOW:
624 			STAT(mesq_noop_page_overflow);
625 			fallthrough;
626 		default:
627 			BUG();
628 		}
629 	}
630 	*mhdr = save_mhdr;
631 	return ret;
632 }
633 
634 /*
635  * Handle a gru_mesq full.
636  */
637 static int send_message_queue_full(void *cb, struct gru_message_queue_desc *mqd,
638 				void *mesg, int lines)
639 {
640 	union gru_mesqhead mqh;
641 	unsigned int limit, head;
642 	unsigned long avalue;
643 	int half, qlines;
644 
645 	/* Determine if switching to first/second half of q */
646 	avalue = gru_get_amo_value(cb);
647 	head = gru_get_amo_value_head(cb);
648 	limit = gru_get_amo_value_limit(cb);
649 
650 	qlines = mqd->qlines;
651 	half = (limit != qlines);
652 
653 	if (half)
654 		mqh = gru_mesq_head(qlines / 2 + 1, qlines);
655 	else
656 		mqh = gru_mesq_head(2, qlines / 2 + 1);
657 
658 	/* Try to get lock for switching head pointer */
659 	gru_gamir(cb, EOP_IR_CLR, HSTATUS(mqd->mq_gpa, half), XTYPE_DW, IMA);
660 	if (gru_wait(cb) != CBS_IDLE)
661 		goto cberr;
662 	if (!gru_get_amo_value(cb)) {
663 		STAT(mesq_qf_locked);
664 		return MQE_QUEUE_FULL;
665 	}
666 
667 	/* Got the lock. Send optional NOP if queue not full, */
668 	if (head != limit) {
669 		if (send_noop_message(cb, mqd, mesg)) {
670 			gru_gamir(cb, EOP_IR_INC, HSTATUS(mqd->mq_gpa, half),
671 					XTYPE_DW, IMA);
672 			if (gru_wait(cb) != CBS_IDLE)
673 				goto cberr;
674 			STAT(mesq_qf_noop_not_full);
675 			return MQIE_AGAIN;
676 		}
677 		avalue++;
678 	}
679 
680 	/* Then flip queuehead to other half of queue. */
681 	gru_gamer(cb, EOP_ERR_CSWAP, mqd->mq_gpa, XTYPE_DW, mqh.val, avalue,
682 							IMA);
683 	if (gru_wait(cb) != CBS_IDLE)
684 		goto cberr;
685 
686 	/* If not successfully in swapping queue head, clear the hstatus lock */
687 	if (gru_get_amo_value(cb) != avalue) {
688 		STAT(mesq_qf_switch_head_failed);
689 		gru_gamir(cb, EOP_IR_INC, HSTATUS(mqd->mq_gpa, half), XTYPE_DW,
690 							IMA);
691 		if (gru_wait(cb) != CBS_IDLE)
692 			goto cberr;
693 	}
694 	return MQIE_AGAIN;
695 cberr:
696 	STAT(mesq_qf_unexpected_error);
697 	return MQE_UNEXPECTED_CB_ERR;
698 }
699 
700 /*
701  * Handle a PUT failure. Note: if message was a 2-line message, one of the
702  * lines might have successfully have been written. Before sending the
703  * message, "present" must be cleared in BOTH lines to prevent the receiver
704  * from prematurely seeing the full message.
705  */
706 static int send_message_put_nacked(void *cb, struct gru_message_queue_desc *mqd,
707 			void *mesg, int lines)
708 {
709 	unsigned long m;
710 	int ret, loops = 200;	/* experimentally determined */
711 
712 	m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
713 	if (lines == 2) {
714 		gru_vset(cb, m, 0, XTYPE_CL, lines, 1, IMA);
715 		if (gru_wait(cb) != CBS_IDLE)
716 			return MQE_UNEXPECTED_CB_ERR;
717 	}
718 	gru_vstore(cb, m, gru_get_tri(mesg), XTYPE_CL, lines, 1, IMA);
719 	if (gru_wait(cb) != CBS_IDLE)
720 		return MQE_UNEXPECTED_CB_ERR;
721 
722 	if (!mqd->interrupt_vector)
723 		return MQE_OK;
724 
725 	/*
726 	 * Send a noop message in order to deliver a cross-partition interrupt
727 	 * to the SSI that contains the target message queue. Normally, the
728 	 * interrupt is automatically delivered by hardware following mesq
729 	 * operations, but some error conditions require explicit delivery.
730 	 * The noop message will trigger delivery. Otherwise partition failures
731 	 * could cause unrecovered errors.
732 	 */
733 	do {
734 		ret = send_noop_message(cb, mqd, mesg);
735 	} while ((ret == MQIE_AGAIN || ret == MQE_CONGESTION) && (loops-- > 0));
736 
737 	if (ret == MQIE_AGAIN || ret == MQE_CONGESTION) {
738 		/*
739 		 * Don't indicate to the app to resend the message, as it's
740 		 * already been successfully sent.  We simply send an OK
741 		 * (rather than fail the send with MQE_UNEXPECTED_CB_ERR),
742 		 * assuming that the other side is receiving enough
743 		 * interrupts to get this message processed anyway.
744 		 */
745 		ret = MQE_OK;
746 	}
747 	return ret;
748 }
749 
750 /*
751  * Handle a gru_mesq failure. Some of these failures are software recoverable
752  * or retryable.
753  */
754 static int send_message_failure(void *cb, struct gru_message_queue_desc *mqd,
755 				void *mesg, int lines)
756 {
757 	int substatus, ret = 0;
758 
759 	substatus = gru_get_cb_message_queue_substatus(cb);
760 	switch (substatus) {
761 	case CBSS_NO_ERROR:
762 		STAT(mesq_send_unexpected_error);
763 		ret = MQE_UNEXPECTED_CB_ERR;
764 		break;
765 	case CBSS_LB_OVERFLOWED:
766 		STAT(mesq_send_lb_overflow);
767 		ret = MQE_CONGESTION;
768 		break;
769 	case CBSS_QLIMIT_REACHED:
770 		STAT(mesq_send_qlimit_reached);
771 		ret = send_message_queue_full(cb, mqd, mesg, lines);
772 		break;
773 	case CBSS_AMO_NACKED:
774 		STAT(mesq_send_amo_nacked);
775 		ret = MQE_CONGESTION;
776 		break;
777 	case CBSS_PUT_NACKED:
778 		STAT(mesq_send_put_nacked);
779 		ret = send_message_put_nacked(cb, mqd, mesg, lines);
780 		break;
781 	case CBSS_PAGE_OVERFLOW:
782 		STAT(mesq_page_overflow);
783 		fallthrough;
784 	default:
785 		BUG();
786 	}
787 	return ret;
788 }
789 
790 /*
791  * Send a message to a message queue
792  * 	mqd	message queue descriptor
793  * 	mesg	message. ust be vaddr within a GSEG
794  * 	bytes	message size (<= 2 CL)
795  */
796 int gru_send_message_gpa(struct gru_message_queue_desc *mqd, void *mesg,
797 				unsigned int bytes)
798 {
799 	struct message_header *mhdr;
800 	void *cb;
801 	void *dsr;
802 	int istatus, clines, ret;
803 
804 	STAT(mesq_send);
805 	BUG_ON(bytes < sizeof(int) || bytes > 2 * GRU_CACHE_LINE_BYTES);
806 
807 	clines = DIV_ROUND_UP(bytes, GRU_CACHE_LINE_BYTES);
808 	if (gru_get_cpu_resources(bytes, &cb, &dsr))
809 		return MQE_BUG_NO_RESOURCES;
810 	memcpy(dsr, mesg, bytes);
811 	mhdr = dsr;
812 	mhdr->present = MQS_FULL;
813 	mhdr->lines = clines;
814 	if (clines == 2) {
815 		mhdr->present2 = get_present2(mhdr);
816 		restore_present2(mhdr, MQS_FULL);
817 	}
818 
819 	do {
820 		ret = MQE_OK;
821 		gru_mesq(cb, mqd->mq_gpa, gru_get_tri(mhdr), clines, IMA);
822 		istatus = gru_wait(cb);
823 		if (istatus != CBS_IDLE)
824 			ret = send_message_failure(cb, mqd, dsr, clines);
825 	} while (ret == MQIE_AGAIN);
826 	gru_free_cpu_resources(cb, dsr);
827 
828 	if (ret)
829 		STAT(mesq_send_failed);
830 	return ret;
831 }
832 EXPORT_SYMBOL_GPL(gru_send_message_gpa);
833 
834 /*
835  * Advance the receive pointer for the queue to the next message.
836  */
837 void gru_free_message(struct gru_message_queue_desc *mqd, void *mesg)
838 {
839 	struct message_queue *mq = mqd->mq;
840 	struct message_header *mhdr = mq->next;
841 	void *next, *pnext;
842 	int half = -1;
843 	int lines = mhdr->lines;
844 
845 	if (lines == 2)
846 		restore_present2(mhdr, MQS_EMPTY);
847 	mhdr->present = MQS_EMPTY;
848 
849 	pnext = mq->next;
850 	next = pnext + GRU_CACHE_LINE_BYTES * lines;
851 	if (next == mq->limit) {
852 		next = mq->start;
853 		half = 1;
854 	} else if (pnext < mq->start2 && next >= mq->start2) {
855 		half = 0;
856 	}
857 
858 	if (half >= 0)
859 		mq->hstatus[half] = 1;
860 	mq->next = next;
861 }
862 EXPORT_SYMBOL_GPL(gru_free_message);
863 
864 /*
865  * Get next message from message queue. Return NULL if no message
866  * present. User must call next_message() to move to next message.
867  * 	rmq	message queue
868  */
869 void *gru_get_next_message(struct gru_message_queue_desc *mqd)
870 {
871 	struct message_queue *mq = mqd->mq;
872 	struct message_header *mhdr = mq->next;
873 	int present = mhdr->present;
874 
875 	/* skip NOOP messages */
876 	while (present == MQS_NOOP) {
877 		gru_free_message(mqd, mhdr);
878 		mhdr = mq->next;
879 		present = mhdr->present;
880 	}
881 
882 	/* Wait for both halves of 2 line messages */
883 	if (present == MQS_FULL && mhdr->lines == 2 &&
884 				get_present2(mhdr) == MQS_EMPTY)
885 		present = MQS_EMPTY;
886 
887 	if (!present) {
888 		STAT(mesq_receive_none);
889 		return NULL;
890 	}
891 
892 	if (mhdr->lines == 2)
893 		restore_present2(mhdr, mhdr->present2);
894 
895 	STAT(mesq_receive);
896 	return mhdr;
897 }
898 EXPORT_SYMBOL_GPL(gru_get_next_message);
899 
900 /* ---------------------- GRU DATA COPY FUNCTIONS ---------------------------*/
901 
902 /*
903  * Load a DW from a global GPA. The GPA can be a memory or MMR address.
904  */
905 int gru_read_gpa(unsigned long *value, unsigned long gpa)
906 {
907 	void *cb;
908 	void *dsr;
909 	int ret, iaa;
910 
911 	STAT(read_gpa);
912 	if (gru_get_cpu_resources(GRU_NUM_KERNEL_DSR_BYTES, &cb, &dsr))
913 		return MQE_BUG_NO_RESOURCES;
914 	iaa = gpa >> 62;
915 	gru_vload_phys(cb, gpa, gru_get_tri(dsr), iaa, IMA);
916 	ret = gru_wait(cb);
917 	if (ret == CBS_IDLE)
918 		*value = *(unsigned long *)dsr;
919 	gru_free_cpu_resources(cb, dsr);
920 	return ret;
921 }
922 EXPORT_SYMBOL_GPL(gru_read_gpa);
923 
924 
925 /*
926  * Copy a block of data using the GRU resources
927  */
928 int gru_copy_gpa(unsigned long dest_gpa, unsigned long src_gpa,
929 				unsigned int bytes)
930 {
931 	void *cb;
932 	void *dsr;
933 	int ret;
934 
935 	STAT(copy_gpa);
936 	if (gru_get_cpu_resources(GRU_NUM_KERNEL_DSR_BYTES, &cb, &dsr))
937 		return MQE_BUG_NO_RESOURCES;
938 	gru_bcopy(cb, src_gpa, dest_gpa, gru_get_tri(dsr),
939 		  XTYPE_B, bytes, GRU_NUM_KERNEL_DSR_CL, IMA);
940 	ret = gru_wait(cb);
941 	gru_free_cpu_resources(cb, dsr);
942 	return ret;
943 }
944 EXPORT_SYMBOL_GPL(gru_copy_gpa);
945 
946 /* ------------------- KERNEL QUICKTESTS RUN AT STARTUP ----------------*/
947 /* 	Temp - will delete after we gain confidence in the GRU		*/
948 
949 static int quicktest0(unsigned long arg)
950 {
951 	unsigned long word0;
952 	unsigned long word1;
953 	void *cb;
954 	void *dsr;
955 	unsigned long *p;
956 	int ret = -EIO;
957 
958 	if (gru_get_cpu_resources(GRU_CACHE_LINE_BYTES, &cb, &dsr))
959 		return MQE_BUG_NO_RESOURCES;
960 	p = dsr;
961 	word0 = MAGIC;
962 	word1 = 0;
963 
964 	gru_vload(cb, uv_gpa(&word0), gru_get_tri(dsr), XTYPE_DW, 1, 1, IMA);
965 	if (gru_wait(cb) != CBS_IDLE) {
966 		printk(KERN_DEBUG "GRU:%d quicktest0: CBR failure 1\n", smp_processor_id());
967 		goto done;
968 	}
969 
970 	if (*p != MAGIC) {
971 		printk(KERN_DEBUG "GRU:%d quicktest0 bad magic 0x%lx\n", smp_processor_id(), *p);
972 		goto done;
973 	}
974 	gru_vstore(cb, uv_gpa(&word1), gru_get_tri(dsr), XTYPE_DW, 1, 1, IMA);
975 	if (gru_wait(cb) != CBS_IDLE) {
976 		printk(KERN_DEBUG "GRU:%d quicktest0: CBR failure 2\n", smp_processor_id());
977 		goto done;
978 	}
979 
980 	if (word0 != word1 || word1 != MAGIC) {
981 		printk(KERN_DEBUG
982 		       "GRU:%d quicktest0 err: found 0x%lx, expected 0x%lx\n",
983 		     smp_processor_id(), word1, MAGIC);
984 		goto done;
985 	}
986 	ret = 0;
987 
988 done:
989 	gru_free_cpu_resources(cb, dsr);
990 	return ret;
991 }
992 
993 #define ALIGNUP(p, q)	((void *)(((unsigned long)(p) + (q) - 1) & ~(q - 1)))
994 
995 static int quicktest1(unsigned long arg)
996 {
997 	struct gru_message_queue_desc mqd;
998 	void *p, *mq;
999 	int i, ret = -EIO;
1000 	char mes[GRU_CACHE_LINE_BYTES], *m;
1001 
1002 	/* Need  1K cacheline aligned that does not cross page boundary */
1003 	p = kmalloc(4096, 0);
1004 	if (p == NULL)
1005 		return -ENOMEM;
1006 	mq = ALIGNUP(p, 1024);
1007 	memset(mes, 0xee, sizeof(mes));
1008 
1009 	gru_create_message_queue(&mqd, mq, 8 * GRU_CACHE_LINE_BYTES, 0, 0, 0);
1010 	for (i = 0; i < 6; i++) {
1011 		mes[8] = i;
1012 		do {
1013 			ret = gru_send_message_gpa(&mqd, mes, sizeof(mes));
1014 		} while (ret == MQE_CONGESTION);
1015 		if (ret)
1016 			break;
1017 	}
1018 	if (ret != MQE_QUEUE_FULL || i != 4) {
1019 		printk(KERN_DEBUG "GRU:%d quicktest1: unexpected status %d, i %d\n",
1020 		       smp_processor_id(), ret, i);
1021 		goto done;
1022 	}
1023 
1024 	for (i = 0; i < 6; i++) {
1025 		m = gru_get_next_message(&mqd);
1026 		if (!m || m[8] != i)
1027 			break;
1028 		gru_free_message(&mqd, m);
1029 	}
1030 	if (i != 4) {
1031 		printk(KERN_DEBUG "GRU:%d quicktest2: bad message, i %d, m %p, m8 %d\n",
1032 			smp_processor_id(), i, m, m ? m[8] : -1);
1033 		goto done;
1034 	}
1035 	ret = 0;
1036 
1037 done:
1038 	kfree(p);
1039 	return ret;
1040 }
1041 
1042 static int quicktest2(unsigned long arg)
1043 {
1044 	static DECLARE_COMPLETION(cmp);
1045 	unsigned long han;
1046 	int blade_id = 0;
1047 	int numcb = 4;
1048 	int ret = 0;
1049 	unsigned long *buf;
1050 	void *cb0, *cb;
1051 	struct gru_control_block_status *gen;
1052 	int i, k, istatus, bytes;
1053 
1054 	bytes = numcb * 4 * 8;
1055 	buf = kmalloc(bytes, GFP_KERNEL);
1056 	if (!buf)
1057 		return -ENOMEM;
1058 
1059 	ret = -EBUSY;
1060 	han = gru_reserve_async_resources(blade_id, numcb, 0, &cmp);
1061 	if (!han)
1062 		goto done;
1063 
1064 	gru_lock_async_resource(han, &cb0, NULL);
1065 	memset(buf, 0xee, bytes);
1066 	for (i = 0; i < numcb; i++)
1067 		gru_vset(cb0 + i * GRU_HANDLE_STRIDE, uv_gpa(&buf[i * 4]), 0,
1068 				XTYPE_DW, 4, 1, IMA_INTERRUPT);
1069 
1070 	ret = 0;
1071 	k = numcb;
1072 	do {
1073 		gru_wait_async_cbr(han);
1074 		for (i = 0; i < numcb; i++) {
1075 			cb = cb0 + i * GRU_HANDLE_STRIDE;
1076 			istatus = gru_check_status(cb);
1077 			if (istatus != CBS_ACTIVE && istatus != CBS_CALL_OS)
1078 				break;
1079 		}
1080 		if (i == numcb)
1081 			continue;
1082 		if (istatus != CBS_IDLE) {
1083 			printk(KERN_DEBUG "GRU:%d quicktest2: cb %d, exception\n", smp_processor_id(), i);
1084 			ret = -EFAULT;
1085 		} else if (buf[4 * i] || buf[4 * i + 1] || buf[4 * i + 2] ||
1086 				buf[4 * i + 3]) {
1087 			printk(KERN_DEBUG "GRU:%d quicktest2:cb %d,  buf 0x%lx, 0x%lx, 0x%lx, 0x%lx\n",
1088 			       smp_processor_id(), i, buf[4 * i], buf[4 * i + 1], buf[4 * i + 2], buf[4 * i + 3]);
1089 			ret = -EIO;
1090 		}
1091 		k--;
1092 		gen = cb;
1093 		gen->istatus = CBS_CALL_OS; /* don't handle this CBR again */
1094 	} while (k);
1095 	BUG_ON(cmp.done);
1096 
1097 	gru_unlock_async_resource(han);
1098 	gru_release_async_resources(han);
1099 done:
1100 	kfree(buf);
1101 	return ret;
1102 }
1103 
1104 #define BUFSIZE 200
1105 static int quicktest3(unsigned long arg)
1106 {
1107 	char buf1[BUFSIZE], buf2[BUFSIZE];
1108 	int ret = 0;
1109 
1110 	memset(buf2, 0, sizeof(buf2));
1111 	memset(buf1, get_cycles() & 255, sizeof(buf1));
1112 	gru_copy_gpa(uv_gpa(buf2), uv_gpa(buf1), BUFSIZE);
1113 	if (memcmp(buf1, buf2, BUFSIZE)) {
1114 		printk(KERN_DEBUG "GRU:%d quicktest3 error\n", smp_processor_id());
1115 		ret = -EIO;
1116 	}
1117 	return ret;
1118 }
1119 
1120 /*
1121  * Debugging only. User hook for various kernel tests
1122  * of driver & gru.
1123  */
1124 int gru_ktest(unsigned long arg)
1125 {
1126 	int ret = -EINVAL;
1127 
1128 	switch (arg & 0xff) {
1129 	case 0:
1130 		ret = quicktest0(arg);
1131 		break;
1132 	case 1:
1133 		ret = quicktest1(arg);
1134 		break;
1135 	case 2:
1136 		ret = quicktest2(arg);
1137 		break;
1138 	case 3:
1139 		ret = quicktest3(arg);
1140 		break;
1141 	case 99:
1142 		ret = gru_free_kernel_contexts();
1143 		break;
1144 	}
1145 	return ret;
1146 
1147 }
1148 
1149 int gru_kservices_init(void)
1150 {
1151 	return 0;
1152 }
1153 
1154 void gru_kservices_exit(void)
1155 {
1156 	if (gru_free_kernel_contexts())
1157 		BUG();
1158 }
1159 
1160