xref: /openbmc/linux/arch/powerpc/perf/hv-24x7.c (revision 91db9311)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Hypervisor supplied "24x7" performance counter support
4  *
5  * Author: Cody P Schafer <cody@linux.vnet.ibm.com>
6  * Copyright 2014 IBM Corporation.
7  */
8 
9 #define pr_fmt(fmt) "hv-24x7: " fmt
10 
11 #include <linux/perf_event.h>
12 #include <linux/rbtree.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 
17 #include <asm/cputhreads.h>
18 #include <asm/firmware.h>
19 #include <asm/hvcall.h>
20 #include <asm/io.h>
21 #include <linux/byteorder/generic.h>
22 
23 #include "hv-24x7.h"
24 #include "hv-24x7-catalog.h"
25 #include "hv-common.h"
26 
27 /* Version of the 24x7 hypervisor API that we should use in this machine. */
28 static int interface_version;
29 
30 /* Whether we have to aggregate result data for some domains. */
31 static bool aggregate_result_elements;
32 
33 static bool domain_is_valid(unsigned domain)
34 {
35 	switch (domain) {
36 #define DOMAIN(n, v, x, c)		\
37 	case HV_PERF_DOMAIN_##n:	\
38 		/* fall through */
39 #include "hv-24x7-domains.h"
40 #undef DOMAIN
41 		return true;
42 	default:
43 		return false;
44 	}
45 }
46 
47 static bool is_physical_domain(unsigned domain)
48 {
49 	switch (domain) {
50 #define DOMAIN(n, v, x, c)		\
51 	case HV_PERF_DOMAIN_##n:	\
52 		return c;
53 #include "hv-24x7-domains.h"
54 #undef DOMAIN
55 	default:
56 		return false;
57 	}
58 }
59 
60 /* Domains for which more than one result element are returned for each event. */
61 static bool domain_needs_aggregation(unsigned int domain)
62 {
63 	return aggregate_result_elements &&
64 			(domain == HV_PERF_DOMAIN_PHYS_CORE ||
65 			 (domain >= HV_PERF_DOMAIN_VCPU_HOME_CORE &&
66 			  domain <= HV_PERF_DOMAIN_VCPU_REMOTE_NODE));
67 }
68 
69 static const char *domain_name(unsigned domain)
70 {
71 	if (!domain_is_valid(domain))
72 		return NULL;
73 
74 	switch (domain) {
75 	case HV_PERF_DOMAIN_PHYS_CHIP:		return "Physical Chip";
76 	case HV_PERF_DOMAIN_PHYS_CORE:		return "Physical Core";
77 	case HV_PERF_DOMAIN_VCPU_HOME_CORE:	return "VCPU Home Core";
78 	case HV_PERF_DOMAIN_VCPU_HOME_CHIP:	return "VCPU Home Chip";
79 	case HV_PERF_DOMAIN_VCPU_HOME_NODE:	return "VCPU Home Node";
80 	case HV_PERF_DOMAIN_VCPU_REMOTE_NODE:	return "VCPU Remote Node";
81 	}
82 
83 	WARN_ON_ONCE(domain);
84 	return NULL;
85 }
86 
87 static bool catalog_entry_domain_is_valid(unsigned domain)
88 {
89 	/* POWER8 doesn't support virtual domains. */
90 	if (interface_version == 1)
91 		return is_physical_domain(domain);
92 	else
93 		return domain_is_valid(domain);
94 }
95 
96 /*
97  * TODO: Merging events:
98  * - Think of the hcall as an interface to a 4d array of counters:
99  *   - x = domains
100  *   - y = indexes in the domain (core, chip, vcpu, node, etc)
101  *   - z = offset into the counter space
102  *   - w = lpars (guest vms, "logical partitions")
103  * - A single request is: x,y,y_last,z,z_last,w,w_last
104  *   - this means we can retrieve a rectangle of counters in y,z for a single x.
105  *
106  * - Things to consider (ignoring w):
107  *   - input  cost_per_request = 16
108  *   - output cost_per_result(ys,zs)  = 8 + 8 * ys + ys * zs
109  *   - limited number of requests per hcall (must fit into 4K bytes)
110  *     - 4k = 16 [buffer header] - 16 [request size] * request_count
111  *     - 255 requests per hcall
112  *   - sometimes it will be more efficient to read extra data and discard
113  */
114 
115 /*
116  * Example usage:
117  *  perf stat -e 'hv_24x7/domain=2,offset=8,vcpu=0,lpar=0xffffffff/'
118  */
119 
120 /* u3 0-6, one of HV_24X7_PERF_DOMAIN */
121 EVENT_DEFINE_RANGE_FORMAT(domain, config, 0, 3);
122 /* u16 */
123 EVENT_DEFINE_RANGE_FORMAT(core, config, 16, 31);
124 EVENT_DEFINE_RANGE_FORMAT(chip, config, 16, 31);
125 EVENT_DEFINE_RANGE_FORMAT(vcpu, config, 16, 31);
126 /* u32, see "data_offset" */
127 EVENT_DEFINE_RANGE_FORMAT(offset, config, 32, 63);
128 /* u16 */
129 EVENT_DEFINE_RANGE_FORMAT(lpar, config1, 0, 15);
130 
131 EVENT_DEFINE_RANGE(reserved1, config,   4, 15);
132 EVENT_DEFINE_RANGE(reserved2, config1, 16, 63);
133 EVENT_DEFINE_RANGE(reserved3, config2,  0, 63);
134 
135 static struct attribute *format_attrs[] = {
136 	&format_attr_domain.attr,
137 	&format_attr_offset.attr,
138 	&format_attr_core.attr,
139 	&format_attr_chip.attr,
140 	&format_attr_vcpu.attr,
141 	&format_attr_lpar.attr,
142 	NULL,
143 };
144 
145 static struct attribute_group format_group = {
146 	.name = "format",
147 	.attrs = format_attrs,
148 };
149 
150 static struct attribute_group event_group = {
151 	.name = "events",
152 	/* .attrs is set in init */
153 };
154 
155 static struct attribute_group event_desc_group = {
156 	.name = "event_descs",
157 	/* .attrs is set in init */
158 };
159 
160 static struct attribute_group event_long_desc_group = {
161 	.name = "event_long_descs",
162 	/* .attrs is set in init */
163 };
164 
165 static struct kmem_cache *hv_page_cache;
166 
167 DEFINE_PER_CPU(int, hv_24x7_txn_flags);
168 DEFINE_PER_CPU(int, hv_24x7_txn_err);
169 
170 struct hv_24x7_hw {
171 	struct perf_event *events[255];
172 };
173 
174 DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw);
175 
176 /*
177  * request_buffer and result_buffer are not required to be 4k aligned,
178  * but are not allowed to cross any 4k boundary. Aligning them to 4k is
179  * the simplest way to ensure that.
180  */
181 #define H24x7_DATA_BUFFER_SIZE	4096
182 DEFINE_PER_CPU(char, hv_24x7_reqb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);
183 DEFINE_PER_CPU(char, hv_24x7_resb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096);
184 
185 static unsigned int max_num_requests(int interface_version)
186 {
187 	return (H24x7_DATA_BUFFER_SIZE - sizeof(struct hv_24x7_request_buffer))
188 		/ H24x7_REQUEST_SIZE(interface_version);
189 }
190 
191 static char *event_name(struct hv_24x7_event_data *ev, int *len)
192 {
193 	*len = be16_to_cpu(ev->event_name_len) - 2;
194 	return (char *)ev->remainder;
195 }
196 
197 static char *event_desc(struct hv_24x7_event_data *ev, int *len)
198 {
199 	unsigned nl = be16_to_cpu(ev->event_name_len);
200 	__be16 *desc_len = (__be16 *)(ev->remainder + nl - 2);
201 
202 	*len = be16_to_cpu(*desc_len) - 2;
203 	return (char *)ev->remainder + nl;
204 }
205 
206 static char *event_long_desc(struct hv_24x7_event_data *ev, int *len)
207 {
208 	unsigned nl = be16_to_cpu(ev->event_name_len);
209 	__be16 *desc_len_ = (__be16 *)(ev->remainder + nl - 2);
210 	unsigned desc_len = be16_to_cpu(*desc_len_);
211 	__be16 *long_desc_len = (__be16 *)(ev->remainder + nl + desc_len - 2);
212 
213 	*len = be16_to_cpu(*long_desc_len) - 2;
214 	return (char *)ev->remainder + nl + desc_len;
215 }
216 
217 static bool event_fixed_portion_is_within(struct hv_24x7_event_data *ev,
218 					  void *end)
219 {
220 	void *start = ev;
221 
222 	return (start + offsetof(struct hv_24x7_event_data, remainder)) < end;
223 }
224 
225 /*
226  * Things we don't check:
227  *  - padding for desc, name, and long/detailed desc is required to be '\0'
228  *    bytes.
229  *
230  *  Return NULL if we pass end,
231  *  Otherwise return the address of the byte just following the event.
232  */
233 static void *event_end(struct hv_24x7_event_data *ev, void *end)
234 {
235 	void *start = ev;
236 	__be16 *dl_, *ldl_;
237 	unsigned dl, ldl;
238 	unsigned nl = be16_to_cpu(ev->event_name_len);
239 
240 	if (nl < 2) {
241 		pr_debug("%s: name length too short: %d", __func__, nl);
242 		return NULL;
243 	}
244 
245 	if (start + nl > end) {
246 		pr_debug("%s: start=%p + nl=%u > end=%p",
247 				__func__, start, nl, end);
248 		return NULL;
249 	}
250 
251 	dl_ = (__be16 *)(ev->remainder + nl - 2);
252 	if (!IS_ALIGNED((uintptr_t)dl_, 2))
253 		pr_warn("desc len not aligned %p", dl_);
254 	dl = be16_to_cpu(*dl_);
255 	if (dl < 2) {
256 		pr_debug("%s: desc len too short: %d", __func__, dl);
257 		return NULL;
258 	}
259 
260 	if (start + nl + dl > end) {
261 		pr_debug("%s: (start=%p + nl=%u + dl=%u)=%p > end=%p",
262 				__func__, start, nl, dl, start + nl + dl, end);
263 		return NULL;
264 	}
265 
266 	ldl_ = (__be16 *)(ev->remainder + nl + dl - 2);
267 	if (!IS_ALIGNED((uintptr_t)ldl_, 2))
268 		pr_warn("long desc len not aligned %p", ldl_);
269 	ldl = be16_to_cpu(*ldl_);
270 	if (ldl < 2) {
271 		pr_debug("%s: long desc len too short (ldl=%u)",
272 				__func__, ldl);
273 		return NULL;
274 	}
275 
276 	if (start + nl + dl + ldl > end) {
277 		pr_debug("%s: start=%p + nl=%u + dl=%u + ldl=%u > end=%p",
278 				__func__, start, nl, dl, ldl, end);
279 		return NULL;
280 	}
281 
282 	return start + nl + dl + ldl;
283 }
284 
285 static long h_get_24x7_catalog_page_(unsigned long phys_4096,
286 				     unsigned long version, unsigned long index)
287 {
288 	pr_devel("h_get_24x7_catalog_page(0x%lx, %lu, %lu)",
289 			phys_4096, version, index);
290 
291 	WARN_ON(!IS_ALIGNED(phys_4096, 4096));
292 
293 	return plpar_hcall_norets(H_GET_24X7_CATALOG_PAGE,
294 			phys_4096, version, index);
295 }
296 
297 static long h_get_24x7_catalog_page(char page[], u64 version, u32 index)
298 {
299 	return h_get_24x7_catalog_page_(virt_to_phys(page),
300 					version, index);
301 }
302 
303 /*
304  * Each event we find in the catalog, will have a sysfs entry. Format the
305  * data for this sysfs entry based on the event's domain.
306  *
307  * Events belonging to the Chip domain can only be monitored in that domain.
308  * i.e the domain for these events is a fixed/knwon value.
309  *
310  * Events belonging to the Core domain can be monitored either in the physical
311  * core or in one of the virtual CPU domains. So the domain value for these
312  * events must be specified by the user (i.e is a required parameter). Format
313  * the Core events with 'domain=?' so the perf-tool can error check required
314  * parameters.
315  *
316  * NOTE: For the Core domain events, rather than making domain a required
317  *	 parameter we could default it to PHYS_CORE and allowe users to
318  *	 override the domain to one of the VCPU domains.
319  *
320  *	 However, this can make the interface a little inconsistent.
321  *
322  *	 If we set domain=2 (PHYS_CHIP) and allow user to override this field
323  *	 the user may be tempted to also modify the "offset=x" field in which
324  *	 can lead to confusing usage. Consider the HPM_PCYC (offset=0x18) and
325  *	 HPM_INST (offset=0x20) events. With:
326  *
327  *		perf stat -e hv_24x7/HPM_PCYC,offset=0x20/
328  *
329  *	we end up monitoring HPM_INST, while the command line has HPM_PCYC.
330  *
331  *	By not assigning a default value to the domain for the Core events,
332  *	we can have simple guidelines:
333  *
334  *		- Specifying values for parameters with "=?" is required.
335  *
336  *		- Specifying (i.e overriding) values for other parameters
337  *		  is undefined.
338  */
339 static char *event_fmt(struct hv_24x7_event_data *event, unsigned domain)
340 {
341 	const char *sindex;
342 	const char *lpar;
343 	const char *domain_str;
344 	char buf[8];
345 
346 	switch (domain) {
347 	case HV_PERF_DOMAIN_PHYS_CHIP:
348 		snprintf(buf, sizeof(buf), "%d", domain);
349 		domain_str = buf;
350 		lpar = "0x0";
351 		sindex = "chip";
352 		break;
353 	case HV_PERF_DOMAIN_PHYS_CORE:
354 		domain_str = "?";
355 		lpar = "0x0";
356 		sindex = "core";
357 		break;
358 	default:
359 		domain_str = "?";
360 		lpar = "?";
361 		sindex = "vcpu";
362 	}
363 
364 	return kasprintf(GFP_KERNEL,
365 			"domain=%s,offset=0x%x,%s=?,lpar=%s",
366 			domain_str,
367 			be16_to_cpu(event->event_counter_offs) +
368 				be16_to_cpu(event->event_group_record_offs),
369 			sindex,
370 			lpar);
371 }
372 
373 /* Avoid trusting fw to NUL terminate strings */
374 static char *memdup_to_str(char *maybe_str, int max_len, gfp_t gfp)
375 {
376 	return kasprintf(gfp, "%.*s", max_len, maybe_str);
377 }
378 
379 static ssize_t device_show_string(struct device *dev,
380 		struct device_attribute *attr, char *buf)
381 {
382 	struct dev_ext_attribute *d;
383 
384 	d = container_of(attr, struct dev_ext_attribute, attr);
385 
386 	return sprintf(buf, "%s\n", (char *)d->var);
387 }
388 
389 static struct attribute *device_str_attr_create_(char *name, char *str)
390 {
391 	struct dev_ext_attribute *attr = kzalloc(sizeof(*attr), GFP_KERNEL);
392 
393 	if (!attr)
394 		return NULL;
395 
396 	sysfs_attr_init(&attr->attr.attr);
397 
398 	attr->var = str;
399 	attr->attr.attr.name = name;
400 	attr->attr.attr.mode = 0444;
401 	attr->attr.show = device_show_string;
402 
403 	return &attr->attr.attr;
404 }
405 
406 /*
407  * Allocate and initialize strings representing event attributes.
408  *
409  * NOTE: The strings allocated here are never destroyed and continue to
410  *	 exist till shutdown. This is to allow us to create as many events
411  *	 from the catalog as possible, even if we encounter errors with some.
412  *	 In case of changes to error paths in future, these may need to be
413  *	 freed by the caller.
414  */
415 static struct attribute *device_str_attr_create(char *name, int name_max,
416 						int name_nonce,
417 						char *str, size_t str_max)
418 {
419 	char *n;
420 	char *s = memdup_to_str(str, str_max, GFP_KERNEL);
421 	struct attribute *a;
422 
423 	if (!s)
424 		return NULL;
425 
426 	if (!name_nonce)
427 		n = kasprintf(GFP_KERNEL, "%.*s", name_max, name);
428 	else
429 		n = kasprintf(GFP_KERNEL, "%.*s__%d", name_max, name,
430 					name_nonce);
431 	if (!n)
432 		goto out_s;
433 
434 	a = device_str_attr_create_(n, s);
435 	if (!a)
436 		goto out_n;
437 
438 	return a;
439 out_n:
440 	kfree(n);
441 out_s:
442 	kfree(s);
443 	return NULL;
444 }
445 
446 static struct attribute *event_to_attr(unsigned ix,
447 				       struct hv_24x7_event_data *event,
448 				       unsigned domain,
449 				       int nonce)
450 {
451 	int event_name_len;
452 	char *ev_name, *a_ev_name, *val;
453 	struct attribute *attr;
454 
455 	if (!domain_is_valid(domain)) {
456 		pr_warn("catalog event %u has invalid domain %u\n",
457 				ix, domain);
458 		return NULL;
459 	}
460 
461 	val = event_fmt(event, domain);
462 	if (!val)
463 		return NULL;
464 
465 	ev_name = event_name(event, &event_name_len);
466 	if (!nonce)
467 		a_ev_name = kasprintf(GFP_KERNEL, "%.*s",
468 				(int)event_name_len, ev_name);
469 	else
470 		a_ev_name = kasprintf(GFP_KERNEL, "%.*s__%d",
471 				(int)event_name_len, ev_name, nonce);
472 
473 	if (!a_ev_name)
474 		goto out_val;
475 
476 	attr = device_str_attr_create_(a_ev_name, val);
477 	if (!attr)
478 		goto out_name;
479 
480 	return attr;
481 out_name:
482 	kfree(a_ev_name);
483 out_val:
484 	kfree(val);
485 	return NULL;
486 }
487 
488 static struct attribute *event_to_desc_attr(struct hv_24x7_event_data *event,
489 					    int nonce)
490 {
491 	int nl, dl;
492 	char *name = event_name(event, &nl);
493 	char *desc = event_desc(event, &dl);
494 
495 	/* If there isn't a description, don't create the sysfs file */
496 	if (!dl)
497 		return NULL;
498 
499 	return device_str_attr_create(name, nl, nonce, desc, dl);
500 }
501 
502 static struct attribute *
503 event_to_long_desc_attr(struct hv_24x7_event_data *event, int nonce)
504 {
505 	int nl, dl;
506 	char *name = event_name(event, &nl);
507 	char *desc = event_long_desc(event, &dl);
508 
509 	/* If there isn't a description, don't create the sysfs file */
510 	if (!dl)
511 		return NULL;
512 
513 	return device_str_attr_create(name, nl, nonce, desc, dl);
514 }
515 
516 static int event_data_to_attrs(unsigned ix, struct attribute **attrs,
517 				   struct hv_24x7_event_data *event, int nonce)
518 {
519 	*attrs = event_to_attr(ix, event, event->domain, nonce);
520 	if (!*attrs)
521 		return -1;
522 
523 	return 0;
524 }
525 
526 /* */
527 struct event_uniq {
528 	struct rb_node node;
529 	const char *name;
530 	int nl;
531 	unsigned ct;
532 	unsigned domain;
533 };
534 
535 static int memord(const void *d1, size_t s1, const void *d2, size_t s2)
536 {
537 	if (s1 < s2)
538 		return 1;
539 	if (s1 > s2)
540 		return -1;
541 
542 	return memcmp(d1, d2, s1);
543 }
544 
545 static int ev_uniq_ord(const void *v1, size_t s1, unsigned d1, const void *v2,
546 		       size_t s2, unsigned d2)
547 {
548 	int r = memord(v1, s1, v2, s2);
549 
550 	if (r)
551 		return r;
552 	if (d1 > d2)
553 		return 1;
554 	if (d2 > d1)
555 		return -1;
556 	return 0;
557 }
558 
559 static int event_uniq_add(struct rb_root *root, const char *name, int nl,
560 			  unsigned domain)
561 {
562 	struct rb_node **new = &(root->rb_node), *parent = NULL;
563 	struct event_uniq *data;
564 
565 	/* Figure out where to put new node */
566 	while (*new) {
567 		struct event_uniq *it;
568 		int result;
569 
570 		it = rb_entry(*new, struct event_uniq, node);
571 		result = ev_uniq_ord(name, nl, domain, it->name, it->nl,
572 					it->domain);
573 
574 		parent = *new;
575 		if (result < 0)
576 			new = &((*new)->rb_left);
577 		else if (result > 0)
578 			new = &((*new)->rb_right);
579 		else {
580 			it->ct++;
581 			pr_info("found a duplicate event %.*s, ct=%u\n", nl,
582 						name, it->ct);
583 			return it->ct;
584 		}
585 	}
586 
587 	data = kmalloc(sizeof(*data), GFP_KERNEL);
588 	if (!data)
589 		return -ENOMEM;
590 
591 	*data = (struct event_uniq) {
592 		.name = name,
593 		.nl = nl,
594 		.ct = 0,
595 		.domain = domain,
596 	};
597 
598 	/* Add new node and rebalance tree. */
599 	rb_link_node(&data->node, parent, new);
600 	rb_insert_color(&data->node, root);
601 
602 	/* data->ct */
603 	return 0;
604 }
605 
606 static void event_uniq_destroy(struct rb_root *root)
607 {
608 	/*
609 	 * the strings we point to are in the giant block of memory filled by
610 	 * the catalog, and are freed separately.
611 	 */
612 	struct event_uniq *pos, *n;
613 
614 	rbtree_postorder_for_each_entry_safe(pos, n, root, node)
615 		kfree(pos);
616 }
617 
618 
619 /*
620  * ensure the event structure's sizes are self consistent and don't cause us to
621  * read outside of the event
622  *
623  * On success, return the event length in bytes.
624  * Otherwise, return -1 (and print as appropriate).
625  */
626 static ssize_t catalog_event_len_validate(struct hv_24x7_event_data *event,
627 					  size_t event_idx,
628 					  size_t event_data_bytes,
629 					  size_t event_entry_count,
630 					  size_t offset, void *end)
631 {
632 	ssize_t ev_len;
633 	void *ev_end, *calc_ev_end;
634 
635 	if (offset >= event_data_bytes)
636 		return -1;
637 
638 	if (event_idx >= event_entry_count) {
639 		pr_devel("catalog event data has %zu bytes of padding after last event\n",
640 				event_data_bytes - offset);
641 		return -1;
642 	}
643 
644 	if (!event_fixed_portion_is_within(event, end)) {
645 		pr_warn("event %zu fixed portion is not within range\n",
646 				event_idx);
647 		return -1;
648 	}
649 
650 	ev_len = be16_to_cpu(event->length);
651 
652 	if (ev_len % 16)
653 		pr_info("event %zu has length %zu not divisible by 16: event=%pK\n",
654 				event_idx, ev_len, event);
655 
656 	ev_end = (__u8 *)event + ev_len;
657 	if (ev_end > end) {
658 		pr_warn("event %zu has .length=%zu, ends after buffer end: ev_end=%pK > end=%pK, offset=%zu\n",
659 				event_idx, ev_len, ev_end, end,
660 				offset);
661 		return -1;
662 	}
663 
664 	calc_ev_end = event_end(event, end);
665 	if (!calc_ev_end) {
666 		pr_warn("event %zu has a calculated length which exceeds buffer length %zu: event=%pK end=%pK, offset=%zu\n",
667 			event_idx, event_data_bytes, event, end,
668 			offset);
669 		return -1;
670 	}
671 
672 	if (calc_ev_end > ev_end) {
673 		pr_warn("event %zu exceeds it's own length: event=%pK, end=%pK, offset=%zu, calc_ev_end=%pK\n",
674 			event_idx, event, ev_end, offset, calc_ev_end);
675 		return -1;
676 	}
677 
678 	return ev_len;
679 }
680 
681 #define MAX_4K (SIZE_MAX / 4096)
682 
683 static int create_events_from_catalog(struct attribute ***events_,
684 				      struct attribute ***event_descs_,
685 				      struct attribute ***event_long_descs_)
686 {
687 	long hret;
688 	size_t catalog_len, catalog_page_len, event_entry_count,
689 	       event_data_len, event_data_offs,
690 	       event_data_bytes, junk_events, event_idx, event_attr_ct, i,
691 	       attr_max, event_idx_last, desc_ct, long_desc_ct;
692 	ssize_t ct, ev_len;
693 	uint64_t catalog_version_num;
694 	struct attribute **events, **event_descs, **event_long_descs;
695 	struct hv_24x7_catalog_page_0 *page_0 =
696 		kmem_cache_alloc(hv_page_cache, GFP_KERNEL);
697 	void *page = page_0;
698 	void *event_data, *end;
699 	struct hv_24x7_event_data *event;
700 	struct rb_root ev_uniq = RB_ROOT;
701 	int ret = 0;
702 
703 	if (!page) {
704 		ret = -ENOMEM;
705 		goto e_out;
706 	}
707 
708 	hret = h_get_24x7_catalog_page(page, 0, 0);
709 	if (hret) {
710 		ret = -EIO;
711 		goto e_free;
712 	}
713 
714 	catalog_version_num = be64_to_cpu(page_0->version);
715 	catalog_page_len = be32_to_cpu(page_0->length);
716 
717 	if (MAX_4K < catalog_page_len) {
718 		pr_err("invalid page count: %zu\n", catalog_page_len);
719 		ret = -EIO;
720 		goto e_free;
721 	}
722 
723 	catalog_len = catalog_page_len * 4096;
724 
725 	event_entry_count = be16_to_cpu(page_0->event_entry_count);
726 	event_data_offs   = be16_to_cpu(page_0->event_data_offs);
727 	event_data_len    = be16_to_cpu(page_0->event_data_len);
728 
729 	pr_devel("cv %llu cl %zu eec %zu edo %zu edl %zu\n",
730 			catalog_version_num, catalog_len,
731 			event_entry_count, event_data_offs, event_data_len);
732 
733 	if ((MAX_4K < event_data_len)
734 			|| (MAX_4K < event_data_offs)
735 			|| (MAX_4K - event_data_offs < event_data_len)) {
736 		pr_err("invalid event data offs %zu and/or len %zu\n",
737 				event_data_offs, event_data_len);
738 		ret = -EIO;
739 		goto e_free;
740 	}
741 
742 	if ((event_data_offs + event_data_len) > catalog_page_len) {
743 		pr_err("event data %zu-%zu does not fit inside catalog 0-%zu\n",
744 				event_data_offs,
745 				event_data_offs + event_data_len,
746 				catalog_page_len);
747 		ret = -EIO;
748 		goto e_free;
749 	}
750 
751 	if (SIZE_MAX - 1 < event_entry_count) {
752 		pr_err("event_entry_count %zu is invalid\n", event_entry_count);
753 		ret = -EIO;
754 		goto e_free;
755 	}
756 
757 	event_data_bytes = event_data_len * 4096;
758 
759 	/*
760 	 * event data can span several pages, events can cross between these
761 	 * pages. Use vmalloc to make this easier.
762 	 */
763 	event_data = vmalloc(event_data_bytes);
764 	if (!event_data) {
765 		pr_err("could not allocate event data\n");
766 		ret = -ENOMEM;
767 		goto e_free;
768 	}
769 
770 	end = event_data + event_data_bytes;
771 
772 	/*
773 	 * using vmalloc_to_phys() like this only works if PAGE_SIZE is
774 	 * divisible by 4096
775 	 */
776 	BUILD_BUG_ON(PAGE_SIZE % 4096);
777 
778 	for (i = 0; i < event_data_len; i++) {
779 		hret = h_get_24x7_catalog_page_(
780 				vmalloc_to_phys(event_data + i * 4096),
781 				catalog_version_num,
782 				i + event_data_offs);
783 		if (hret) {
784 			pr_err("Failed to get event data in page %zu: rc=%ld\n",
785 			       i + event_data_offs, hret);
786 			ret = -EIO;
787 			goto e_event_data;
788 		}
789 	}
790 
791 	/*
792 	 * scan the catalog to determine the number of attributes we need, and
793 	 * verify it at the same time.
794 	 */
795 	for (junk_events = 0, event = event_data, event_idx = 0, attr_max = 0;
796 	     ;
797 	     event_idx++, event = (void *)event + ev_len) {
798 		size_t offset = (void *)event - (void *)event_data;
799 		char *name;
800 		int nl;
801 
802 		ev_len = catalog_event_len_validate(event, event_idx,
803 						    event_data_bytes,
804 						    event_entry_count,
805 						    offset, end);
806 		if (ev_len < 0)
807 			break;
808 
809 		name = event_name(event, &nl);
810 
811 		if (event->event_group_record_len == 0) {
812 			pr_devel("invalid event %zu (%.*s): group_record_len == 0, skipping\n",
813 					event_idx, nl, name);
814 			junk_events++;
815 			continue;
816 		}
817 
818 		if (!catalog_entry_domain_is_valid(event->domain)) {
819 			pr_info("event %zu (%.*s) has invalid domain %d\n",
820 					event_idx, nl, name, event->domain);
821 			junk_events++;
822 			continue;
823 		}
824 
825 		attr_max++;
826 	}
827 
828 	event_idx_last = event_idx;
829 	if (event_idx_last != event_entry_count)
830 		pr_warn("event buffer ended before listed # of events were parsed (got %zu, wanted %zu, junk %zu)\n",
831 				event_idx_last, event_entry_count, junk_events);
832 
833 	events = kmalloc_array(attr_max + 1, sizeof(*events), GFP_KERNEL);
834 	if (!events) {
835 		ret = -ENOMEM;
836 		goto e_event_data;
837 	}
838 
839 	event_descs = kmalloc_array(event_idx + 1, sizeof(*event_descs),
840 				GFP_KERNEL);
841 	if (!event_descs) {
842 		ret = -ENOMEM;
843 		goto e_event_attrs;
844 	}
845 
846 	event_long_descs = kmalloc_array(event_idx + 1,
847 			sizeof(*event_long_descs), GFP_KERNEL);
848 	if (!event_long_descs) {
849 		ret = -ENOMEM;
850 		goto e_event_descs;
851 	}
852 
853 	/* Iterate over the catalog filling in the attribute vector */
854 	for (junk_events = 0, event_attr_ct = 0, desc_ct = 0, long_desc_ct = 0,
855 				event = event_data, event_idx = 0;
856 			event_idx < event_idx_last;
857 			event_idx++, ev_len = be16_to_cpu(event->length),
858 				event = (void *)event + ev_len) {
859 		char *name;
860 		int nl;
861 		int nonce;
862 		/*
863 		 * these are the only "bad" events that are intermixed and that
864 		 * we can ignore without issue. make sure to skip them here
865 		 */
866 		if (event->event_group_record_len == 0)
867 			continue;
868 		if (!catalog_entry_domain_is_valid(event->domain))
869 			continue;
870 
871 		name  = event_name(event, &nl);
872 		nonce = event_uniq_add(&ev_uniq, name, nl, event->domain);
873 		ct    = event_data_to_attrs(event_idx, events + event_attr_ct,
874 					    event, nonce);
875 		if (ct < 0) {
876 			pr_warn("event %zu (%.*s) creation failure, skipping\n",
877 				event_idx, nl, name);
878 			junk_events++;
879 		} else {
880 			event_attr_ct++;
881 			event_descs[desc_ct] = event_to_desc_attr(event, nonce);
882 			if (event_descs[desc_ct])
883 				desc_ct++;
884 			event_long_descs[long_desc_ct] =
885 					event_to_long_desc_attr(event, nonce);
886 			if (event_long_descs[long_desc_ct])
887 				long_desc_ct++;
888 		}
889 	}
890 
891 	pr_info("read %zu catalog entries, created %zu event attrs (%zu failures), %zu descs\n",
892 			event_idx, event_attr_ct, junk_events, desc_ct);
893 
894 	events[event_attr_ct] = NULL;
895 	event_descs[desc_ct] = NULL;
896 	event_long_descs[long_desc_ct] = NULL;
897 
898 	event_uniq_destroy(&ev_uniq);
899 	vfree(event_data);
900 	kmem_cache_free(hv_page_cache, page);
901 
902 	*events_ = events;
903 	*event_descs_ = event_descs;
904 	*event_long_descs_ = event_long_descs;
905 	return 0;
906 
907 e_event_descs:
908 	kfree(event_descs);
909 e_event_attrs:
910 	kfree(events);
911 e_event_data:
912 	vfree(event_data);
913 e_free:
914 	kmem_cache_free(hv_page_cache, page);
915 e_out:
916 	*events_ = NULL;
917 	*event_descs_ = NULL;
918 	*event_long_descs_ = NULL;
919 	return ret;
920 }
921 
922 static ssize_t catalog_read(struct file *filp, struct kobject *kobj,
923 			    struct bin_attribute *bin_attr, char *buf,
924 			    loff_t offset, size_t count)
925 {
926 	long hret;
927 	ssize_t ret = 0;
928 	size_t catalog_len = 0, catalog_page_len = 0;
929 	loff_t page_offset = 0;
930 	loff_t offset_in_page;
931 	size_t copy_len;
932 	uint64_t catalog_version_num = 0;
933 	void *page = kmem_cache_alloc(hv_page_cache, GFP_USER);
934 	struct hv_24x7_catalog_page_0 *page_0 = page;
935 
936 	if (!page)
937 		return -ENOMEM;
938 
939 	hret = h_get_24x7_catalog_page(page, 0, 0);
940 	if (hret) {
941 		ret = -EIO;
942 		goto e_free;
943 	}
944 
945 	catalog_version_num = be64_to_cpu(page_0->version);
946 	catalog_page_len = be32_to_cpu(page_0->length);
947 	catalog_len = catalog_page_len * 4096;
948 
949 	page_offset = offset / 4096;
950 	offset_in_page = offset % 4096;
951 
952 	if (page_offset >= catalog_page_len)
953 		goto e_free;
954 
955 	if (page_offset != 0) {
956 		hret = h_get_24x7_catalog_page(page, catalog_version_num,
957 					       page_offset);
958 		if (hret) {
959 			ret = -EIO;
960 			goto e_free;
961 		}
962 	}
963 
964 	copy_len = 4096 - offset_in_page;
965 	if (copy_len > count)
966 		copy_len = count;
967 
968 	memcpy(buf, page+offset_in_page, copy_len);
969 	ret = copy_len;
970 
971 e_free:
972 	if (hret)
973 		pr_err("h_get_24x7_catalog_page(ver=%lld, page=%lld) failed:"
974 		       " rc=%ld\n",
975 		       catalog_version_num, page_offset, hret);
976 	kmem_cache_free(hv_page_cache, page);
977 
978 	pr_devel("catalog_read: offset=%lld(%lld) count=%zu "
979 			"catalog_len=%zu(%zu) => %zd\n", offset, page_offset,
980 			count, catalog_len, catalog_page_len, ret);
981 
982 	return ret;
983 }
984 
985 static ssize_t domains_show(struct device *dev, struct device_attribute *attr,
986 			    char *page)
987 {
988 	int d, n, count = 0;
989 	const char *str;
990 
991 	for (d = 0; d < HV_PERF_DOMAIN_MAX; d++) {
992 		str = domain_name(d);
993 		if (!str)
994 			continue;
995 
996 		n = sprintf(page, "%d: %s\n", d, str);
997 		if (n < 0)
998 			break;
999 
1000 		count += n;
1001 		page += n;
1002 	}
1003 	return count;
1004 }
1005 
1006 #define PAGE_0_ATTR(_name, _fmt, _expr)				\
1007 static ssize_t _name##_show(struct device *dev,			\
1008 			    struct device_attribute *dev_attr,	\
1009 			    char *buf)				\
1010 {								\
1011 	long hret;						\
1012 	ssize_t ret = 0;					\
1013 	void *page = kmem_cache_alloc(hv_page_cache, GFP_USER);	\
1014 	struct hv_24x7_catalog_page_0 *page_0 = page;		\
1015 	if (!page)						\
1016 		return -ENOMEM;					\
1017 	hret = h_get_24x7_catalog_page(page, 0, 0);		\
1018 	if (hret) {						\
1019 		ret = -EIO;					\
1020 		goto e_free;					\
1021 	}							\
1022 	ret = sprintf(buf, _fmt, _expr);			\
1023 e_free:								\
1024 	kmem_cache_free(hv_page_cache, page);			\
1025 	return ret;						\
1026 }								\
1027 static DEVICE_ATTR_RO(_name)
1028 
1029 PAGE_0_ATTR(catalog_version, "%lld\n",
1030 		(unsigned long long)be64_to_cpu(page_0->version));
1031 PAGE_0_ATTR(catalog_len, "%lld\n",
1032 		(unsigned long long)be32_to_cpu(page_0->length) * 4096);
1033 static BIN_ATTR_RO(catalog, 0/* real length varies */);
1034 static DEVICE_ATTR_RO(domains);
1035 
1036 static struct bin_attribute *if_bin_attrs[] = {
1037 	&bin_attr_catalog,
1038 	NULL,
1039 };
1040 
1041 static struct attribute *if_attrs[] = {
1042 	&dev_attr_catalog_len.attr,
1043 	&dev_attr_catalog_version.attr,
1044 	&dev_attr_domains.attr,
1045 	NULL,
1046 };
1047 
1048 static struct attribute_group if_group = {
1049 	.name = "interface",
1050 	.bin_attrs = if_bin_attrs,
1051 	.attrs = if_attrs,
1052 };
1053 
1054 static const struct attribute_group *attr_groups[] = {
1055 	&format_group,
1056 	&event_group,
1057 	&event_desc_group,
1058 	&event_long_desc_group,
1059 	&if_group,
1060 	NULL,
1061 };
1062 
1063 /*
1064  * Start the process for a new H_GET_24x7_DATA hcall.
1065  */
1066 static void init_24x7_request(struct hv_24x7_request_buffer *request_buffer,
1067 			      struct hv_24x7_data_result_buffer *result_buffer)
1068 {
1069 
1070 	memset(request_buffer, 0, H24x7_DATA_BUFFER_SIZE);
1071 	memset(result_buffer, 0, H24x7_DATA_BUFFER_SIZE);
1072 
1073 	request_buffer->interface_version = interface_version;
1074 	/* memset above set request_buffer->num_requests to 0 */
1075 }
1076 
1077 /*
1078  * Commit (i.e perform) the H_GET_24x7_DATA hcall using the data collected
1079  * by 'init_24x7_request()' and 'add_event_to_24x7_request()'.
1080  */
1081 static int make_24x7_request(struct hv_24x7_request_buffer *request_buffer,
1082 			     struct hv_24x7_data_result_buffer *result_buffer)
1083 {
1084 	long ret;
1085 
1086 	/*
1087 	 * NOTE: Due to variable number of array elements in request and
1088 	 *	 result buffer(s), sizeof() is not reliable. Use the actual
1089 	 *	 allocated buffer size, H24x7_DATA_BUFFER_SIZE.
1090 	 */
1091 	ret = plpar_hcall_norets(H_GET_24X7_DATA,
1092 			virt_to_phys(request_buffer), H24x7_DATA_BUFFER_SIZE,
1093 			virt_to_phys(result_buffer),  H24x7_DATA_BUFFER_SIZE);
1094 
1095 	if (ret) {
1096 		struct hv_24x7_request *req;
1097 
1098 		req = request_buffer->requests;
1099 		pr_notice_ratelimited("hcall failed: [%d %#x %#x %d] => ret 0x%lx (%ld) detail=0x%x failing ix=%x\n",
1100 				      req->performance_domain, req->data_offset,
1101 				      req->starting_ix, req->starting_lpar_ix,
1102 				      ret, ret, result_buffer->detailed_rc,
1103 				      result_buffer->failing_request_ix);
1104 		return -EIO;
1105 	}
1106 
1107 	return 0;
1108 }
1109 
1110 /*
1111  * Add the given @event to the next slot in the 24x7 request_buffer.
1112  *
1113  * Note that H_GET_24X7_DATA hcall allows reading several counters'
1114  * values in a single HCALL. We expect the caller to add events to the
1115  * request buffer one by one, make the HCALL and process the results.
1116  */
1117 static int add_event_to_24x7_request(struct perf_event *event,
1118 				struct hv_24x7_request_buffer *request_buffer)
1119 {
1120 	u16 idx;
1121 	int i;
1122 	size_t req_size;
1123 	struct hv_24x7_request *req;
1124 
1125 	if (request_buffer->num_requests >=
1126 	    max_num_requests(request_buffer->interface_version)) {
1127 		pr_devel("Too many requests for 24x7 HCALL %d\n",
1128 				request_buffer->num_requests);
1129 		return -EINVAL;
1130 	}
1131 
1132 	switch (event_get_domain(event)) {
1133 	case HV_PERF_DOMAIN_PHYS_CHIP:
1134 		idx = event_get_chip(event);
1135 		break;
1136 	case HV_PERF_DOMAIN_PHYS_CORE:
1137 		idx = event_get_core(event);
1138 		break;
1139 	default:
1140 		idx = event_get_vcpu(event);
1141 	}
1142 
1143 	req_size = H24x7_REQUEST_SIZE(request_buffer->interface_version);
1144 
1145 	i = request_buffer->num_requests++;
1146 	req = (void *) request_buffer->requests + i * req_size;
1147 
1148 	req->performance_domain = event_get_domain(event);
1149 	req->data_size = cpu_to_be16(8);
1150 	req->data_offset = cpu_to_be32(event_get_offset(event));
1151 	req->starting_lpar_ix = cpu_to_be16(event_get_lpar(event));
1152 	req->max_num_lpars = cpu_to_be16(1);
1153 	req->starting_ix = cpu_to_be16(idx);
1154 	req->max_ix = cpu_to_be16(1);
1155 
1156 	if (request_buffer->interface_version > 1) {
1157 		if (domain_needs_aggregation(req->performance_domain))
1158 			req->max_num_thread_groups = -1;
1159 		else if (req->performance_domain != HV_PERF_DOMAIN_PHYS_CHIP) {
1160 			req->starting_thread_group_ix = idx % 2;
1161 			req->max_num_thread_groups = 1;
1162 		}
1163 	}
1164 
1165 	return 0;
1166 }
1167 
1168 /**
1169  * get_count_from_result - get event count from all result elements in result
1170  *
1171  * If the event corresponding to this result needs aggregation of the result
1172  * element values, then this function does that.
1173  *
1174  * @event:	Event associated with @res.
1175  * @resb:	Result buffer containing @res.
1176  * @res:	Result to work on.
1177  * @countp:	Output variable containing the event count.
1178  * @next:	Optional output variable pointing to the next result in @resb.
1179  */
1180 static int get_count_from_result(struct perf_event *event,
1181 				 struct hv_24x7_data_result_buffer *resb,
1182 				 struct hv_24x7_result *res, u64 *countp,
1183 				 struct hv_24x7_result **next)
1184 {
1185 	u16 num_elements = be16_to_cpu(res->num_elements_returned);
1186 	u16 data_size = be16_to_cpu(res->result_element_data_size);
1187 	unsigned int data_offset;
1188 	void *element_data;
1189 	int i;
1190 	u64 count;
1191 
1192 	/*
1193 	 * We can bail out early if the result is empty.
1194 	 */
1195 	if (!num_elements) {
1196 		pr_debug("Result of request %hhu is empty, nothing to do\n",
1197 			 res->result_ix);
1198 
1199 		if (next)
1200 			*next = (struct hv_24x7_result *) res->elements;
1201 
1202 		return -ENODATA;
1203 	}
1204 
1205 	/*
1206 	 * Since we always specify 1 as the maximum for the smallest resource
1207 	 * we're requesting, there should to be only one element per result.
1208 	 * Except when an event needs aggregation, in which case there are more.
1209 	 */
1210 	if (num_elements != 1 &&
1211 	    !domain_needs_aggregation(event_get_domain(event))) {
1212 		pr_err("Error: result of request %hhu has %hu elements\n",
1213 		       res->result_ix, num_elements);
1214 
1215 		return -EIO;
1216 	}
1217 
1218 	if (data_size != sizeof(u64)) {
1219 		pr_debug("Error: result of request %hhu has data of %hu bytes\n",
1220 			 res->result_ix, data_size);
1221 
1222 		return -ENOTSUPP;
1223 	}
1224 
1225 	if (resb->interface_version == 1)
1226 		data_offset = offsetof(struct hv_24x7_result_element_v1,
1227 				       element_data);
1228 	else
1229 		data_offset = offsetof(struct hv_24x7_result_element_v2,
1230 				       element_data);
1231 
1232 	/* Go through the result elements in the result. */
1233 	for (i = count = 0, element_data = res->elements + data_offset;
1234 	     i < num_elements;
1235 	     i++, element_data += data_size + data_offset)
1236 		count += be64_to_cpu(*((u64 *) element_data));
1237 
1238 	*countp = count;
1239 
1240 	/* The next result is after the last result element. */
1241 	if (next)
1242 		*next = element_data - data_offset;
1243 
1244 	return 0;
1245 }
1246 
1247 static int single_24x7_request(struct perf_event *event, u64 *count)
1248 {
1249 	int ret;
1250 	struct hv_24x7_request_buffer *request_buffer;
1251 	struct hv_24x7_data_result_buffer *result_buffer;
1252 
1253 	BUILD_BUG_ON(sizeof(*request_buffer) > 4096);
1254 	BUILD_BUG_ON(sizeof(*result_buffer) > 4096);
1255 
1256 	request_buffer = (void *)get_cpu_var(hv_24x7_reqb);
1257 	result_buffer = (void *)get_cpu_var(hv_24x7_resb);
1258 
1259 	init_24x7_request(request_buffer, result_buffer);
1260 
1261 	ret = add_event_to_24x7_request(event, request_buffer);
1262 	if (ret)
1263 		goto out;
1264 
1265 	ret = make_24x7_request(request_buffer, result_buffer);
1266 	if (ret)
1267 		goto out;
1268 
1269 	/* process result from hcall */
1270 	ret = get_count_from_result(event, result_buffer,
1271 				    result_buffer->results, count, NULL);
1272 
1273 out:
1274 	put_cpu_var(hv_24x7_reqb);
1275 	put_cpu_var(hv_24x7_resb);
1276 	return ret;
1277 }
1278 
1279 
1280 static int h_24x7_event_init(struct perf_event *event)
1281 {
1282 	struct hv_perf_caps caps;
1283 	unsigned domain;
1284 	unsigned long hret;
1285 	u64 ct;
1286 
1287 	/* Not our event */
1288 	if (event->attr.type != event->pmu->type)
1289 		return -ENOENT;
1290 
1291 	/* Unused areas must be 0 */
1292 	if (event_get_reserved1(event) ||
1293 	    event_get_reserved2(event) ||
1294 	    event_get_reserved3(event)) {
1295 		pr_devel("reserved set when forbidden 0x%llx(0x%llx) 0x%llx(0x%llx) 0x%llx(0x%llx)\n",
1296 				event->attr.config,
1297 				event_get_reserved1(event),
1298 				event->attr.config1,
1299 				event_get_reserved2(event),
1300 				event->attr.config2,
1301 				event_get_reserved3(event));
1302 		return -EINVAL;
1303 	}
1304 
1305 	/* no branch sampling */
1306 	if (has_branch_stack(event))
1307 		return -EOPNOTSUPP;
1308 
1309 	/* offset must be 8 byte aligned */
1310 	if (event_get_offset(event) % 8) {
1311 		pr_devel("bad alignment\n");
1312 		return -EINVAL;
1313 	}
1314 
1315 	domain = event_get_domain(event);
1316 	if (domain >= HV_PERF_DOMAIN_MAX) {
1317 		pr_devel("invalid domain %d\n", domain);
1318 		return -EINVAL;
1319 	}
1320 
1321 	hret = hv_perf_caps_get(&caps);
1322 	if (hret) {
1323 		pr_devel("could not get capabilities: rc=%ld\n", hret);
1324 		return -EIO;
1325 	}
1326 
1327 	/* Physical domains & other lpars require extra capabilities */
1328 	if (!caps.collect_privileged && (is_physical_domain(domain) ||
1329 		(event_get_lpar(event) != event_get_lpar_max()))) {
1330 		pr_devel("hv permissions disallow: is_physical_domain:%d, lpar=0x%llx\n",
1331 				is_physical_domain(domain),
1332 				event_get_lpar(event));
1333 		return -EACCES;
1334 	}
1335 
1336 	/* Get the initial value of the counter for this event */
1337 	if (single_24x7_request(event, &ct)) {
1338 		pr_devel("test hcall failed\n");
1339 		return -EIO;
1340 	}
1341 	(void)local64_xchg(&event->hw.prev_count, ct);
1342 
1343 	return 0;
1344 }
1345 
1346 static u64 h_24x7_get_value(struct perf_event *event)
1347 {
1348 	u64 ct;
1349 
1350 	if (single_24x7_request(event, &ct))
1351 		/* We checked this in event init, shouldn't fail here... */
1352 		return 0;
1353 
1354 	return ct;
1355 }
1356 
1357 static void update_event_count(struct perf_event *event, u64 now)
1358 {
1359 	s64 prev;
1360 
1361 	prev = local64_xchg(&event->hw.prev_count, now);
1362 	local64_add(now - prev, &event->count);
1363 }
1364 
1365 static void h_24x7_event_read(struct perf_event *event)
1366 {
1367 	u64 now;
1368 	struct hv_24x7_request_buffer *request_buffer;
1369 	struct hv_24x7_hw *h24x7hw;
1370 	int txn_flags;
1371 
1372 	txn_flags = __this_cpu_read(hv_24x7_txn_flags);
1373 
1374 	/*
1375 	 * If in a READ transaction, add this counter to the list of
1376 	 * counters to read during the next HCALL (i.e commit_txn()).
1377 	 * If not in a READ transaction, go ahead and make the HCALL
1378 	 * to read this counter by itself.
1379 	 */
1380 
1381 	if (txn_flags & PERF_PMU_TXN_READ) {
1382 		int i;
1383 		int ret;
1384 
1385 		if (__this_cpu_read(hv_24x7_txn_err))
1386 			return;
1387 
1388 		request_buffer = (void *)get_cpu_var(hv_24x7_reqb);
1389 
1390 		ret = add_event_to_24x7_request(event, request_buffer);
1391 		if (ret) {
1392 			__this_cpu_write(hv_24x7_txn_err, ret);
1393 		} else {
1394 			/*
1395 			 * Associate the event with the HCALL request index,
1396 			 * so ->commit_txn() can quickly find/update count.
1397 			 */
1398 			i = request_buffer->num_requests - 1;
1399 
1400 			h24x7hw = &get_cpu_var(hv_24x7_hw);
1401 			h24x7hw->events[i] = event;
1402 			put_cpu_var(h24x7hw);
1403 			/*
1404 			 * Clear the event count so we can compute the _change_
1405 			 * in the 24x7 raw counter value at the end of the txn.
1406 			 *
1407 			 * Note that we could alternatively read the 24x7 value
1408 			 * now and save its value in event->hw.prev_count. But
1409 			 * that would require issuing a hcall, which would then
1410 			 * defeat the purpose of using the txn interface.
1411 			 */
1412 			local64_set(&event->count, 0);
1413 		}
1414 
1415 		put_cpu_var(hv_24x7_reqb);
1416 	} else {
1417 		now = h_24x7_get_value(event);
1418 		update_event_count(event, now);
1419 	}
1420 }
1421 
1422 static void h_24x7_event_start(struct perf_event *event, int flags)
1423 {
1424 	if (flags & PERF_EF_RELOAD)
1425 		local64_set(&event->hw.prev_count, h_24x7_get_value(event));
1426 }
1427 
1428 static void h_24x7_event_stop(struct perf_event *event, int flags)
1429 {
1430 	h_24x7_event_read(event);
1431 }
1432 
1433 static int h_24x7_event_add(struct perf_event *event, int flags)
1434 {
1435 	if (flags & PERF_EF_START)
1436 		h_24x7_event_start(event, flags);
1437 
1438 	return 0;
1439 }
1440 
1441 /*
1442  * 24x7 counters only support READ transactions. They are
1443  * always counting and dont need/support ADD transactions.
1444  * Cache the flags, but otherwise ignore transactions that
1445  * are not PERF_PMU_TXN_READ.
1446  */
1447 static void h_24x7_event_start_txn(struct pmu *pmu, unsigned int flags)
1448 {
1449 	struct hv_24x7_request_buffer *request_buffer;
1450 	struct hv_24x7_data_result_buffer *result_buffer;
1451 
1452 	/* We should not be called if we are already in a txn */
1453 	WARN_ON_ONCE(__this_cpu_read(hv_24x7_txn_flags));
1454 
1455 	__this_cpu_write(hv_24x7_txn_flags, flags);
1456 	if (flags & ~PERF_PMU_TXN_READ)
1457 		return;
1458 
1459 	request_buffer = (void *)get_cpu_var(hv_24x7_reqb);
1460 	result_buffer = (void *)get_cpu_var(hv_24x7_resb);
1461 
1462 	init_24x7_request(request_buffer, result_buffer);
1463 
1464 	put_cpu_var(hv_24x7_resb);
1465 	put_cpu_var(hv_24x7_reqb);
1466 }
1467 
1468 /*
1469  * Clean up transaction state.
1470  *
1471  * NOTE: Ignore state of request and result buffers for now.
1472  *	 We will initialize them during the next read/txn.
1473  */
1474 static void reset_txn(void)
1475 {
1476 	__this_cpu_write(hv_24x7_txn_flags, 0);
1477 	__this_cpu_write(hv_24x7_txn_err, 0);
1478 }
1479 
1480 /*
1481  * 24x7 counters only support READ transactions. They are always counting
1482  * and dont need/support ADD transactions. Clear ->txn_flags but otherwise
1483  * ignore transactions that are not of type PERF_PMU_TXN_READ.
1484  *
1485  * For READ transactions, submit all pending 24x7 requests (i.e requests
1486  * that were queued by h_24x7_event_read()), to the hypervisor and update
1487  * the event counts.
1488  */
1489 static int h_24x7_event_commit_txn(struct pmu *pmu)
1490 {
1491 	struct hv_24x7_request_buffer *request_buffer;
1492 	struct hv_24x7_data_result_buffer *result_buffer;
1493 	struct hv_24x7_result *res, *next_res;
1494 	u64 count;
1495 	int i, ret, txn_flags;
1496 	struct hv_24x7_hw *h24x7hw;
1497 
1498 	txn_flags = __this_cpu_read(hv_24x7_txn_flags);
1499 	WARN_ON_ONCE(!txn_flags);
1500 
1501 	ret = 0;
1502 	if (txn_flags & ~PERF_PMU_TXN_READ)
1503 		goto out;
1504 
1505 	ret = __this_cpu_read(hv_24x7_txn_err);
1506 	if (ret)
1507 		goto out;
1508 
1509 	request_buffer = (void *)get_cpu_var(hv_24x7_reqb);
1510 	result_buffer = (void *)get_cpu_var(hv_24x7_resb);
1511 
1512 	ret = make_24x7_request(request_buffer, result_buffer);
1513 	if (ret)
1514 		goto put_reqb;
1515 
1516 	h24x7hw = &get_cpu_var(hv_24x7_hw);
1517 
1518 	/* Go through results in the result buffer to update event counts. */
1519 	for (i = 0, res = result_buffer->results;
1520 	     i < result_buffer->num_results; i++, res = next_res) {
1521 		struct perf_event *event = h24x7hw->events[res->result_ix];
1522 
1523 		ret = get_count_from_result(event, result_buffer, res, &count,
1524 					    &next_res);
1525 		if (ret)
1526 			break;
1527 
1528 		update_event_count(event, count);
1529 	}
1530 
1531 	put_cpu_var(hv_24x7_hw);
1532 
1533 put_reqb:
1534 	put_cpu_var(hv_24x7_resb);
1535 	put_cpu_var(hv_24x7_reqb);
1536 out:
1537 	reset_txn();
1538 	return ret;
1539 }
1540 
1541 /*
1542  * 24x7 counters only support READ transactions. They are always counting
1543  * and dont need/support ADD transactions. However, regardless of type
1544  * of transaction, all we need to do is cleanup, so we don't have to check
1545  * the type of transaction.
1546  */
1547 static void h_24x7_event_cancel_txn(struct pmu *pmu)
1548 {
1549 	WARN_ON_ONCE(!__this_cpu_read(hv_24x7_txn_flags));
1550 	reset_txn();
1551 }
1552 
1553 static struct pmu h_24x7_pmu = {
1554 	.task_ctx_nr = perf_invalid_context,
1555 
1556 	.name = "hv_24x7",
1557 	.attr_groups = attr_groups,
1558 	.event_init  = h_24x7_event_init,
1559 	.add         = h_24x7_event_add,
1560 	.del         = h_24x7_event_stop,
1561 	.start       = h_24x7_event_start,
1562 	.stop        = h_24x7_event_stop,
1563 	.read        = h_24x7_event_read,
1564 	.start_txn   = h_24x7_event_start_txn,
1565 	.commit_txn  = h_24x7_event_commit_txn,
1566 	.cancel_txn  = h_24x7_event_cancel_txn,
1567 	.capabilities = PERF_PMU_CAP_NO_EXCLUDE,
1568 };
1569 
1570 static int hv_24x7_init(void)
1571 {
1572 	int r;
1573 	unsigned long hret;
1574 	struct hv_perf_caps caps;
1575 
1576 	if (!firmware_has_feature(FW_FEATURE_LPAR)) {
1577 		pr_debug("not a virtualized system, not enabling\n");
1578 		return -ENODEV;
1579 	} else if (!cur_cpu_spec->oprofile_cpu_type)
1580 		return -ENODEV;
1581 
1582 	/* POWER8 only supports v1, while POWER9 only supports v2. */
1583 	if (!strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power8"))
1584 		interface_version = 1;
1585 	else {
1586 		interface_version = 2;
1587 
1588 		/* SMT8 in POWER9 needs to aggregate result elements. */
1589 		if (threads_per_core == 8)
1590 			aggregate_result_elements = true;
1591 	}
1592 
1593 	hret = hv_perf_caps_get(&caps);
1594 	if (hret) {
1595 		pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
1596 				hret);
1597 		return -ENODEV;
1598 	}
1599 
1600 	hv_page_cache = kmem_cache_create("hv-page-4096", 4096, 4096, 0, NULL);
1601 	if (!hv_page_cache)
1602 		return -ENOMEM;
1603 
1604 	/* sampling not supported */
1605 	h_24x7_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
1606 
1607 	r = create_events_from_catalog(&event_group.attrs,
1608 				   &event_desc_group.attrs,
1609 				   &event_long_desc_group.attrs);
1610 
1611 	if (r)
1612 		return r;
1613 
1614 	r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1);
1615 	if (r)
1616 		return r;
1617 
1618 	return 0;
1619 }
1620 
1621 device_initcall(hv_24x7_init);
1622