1/*
  2 * Hypervisor supplied "gpci" ("get performance counter info") performance
  3 * counter support
  4 *
  5 * Author: Cody P Schafer <cody@linux.vnet.ibm.com>
  6 * Copyright 2014 IBM Corporation.
  7 *
  8 * This program is free software; you can redistribute it and/or
  9 * modify it under the terms of the GNU General Public License
 10 * as published by the Free Software Foundation; either version
 11 * 2 of the License, or (at your option) any later version.
 12 */
 13
 14#define pr_fmt(fmt) "hv-gpci: " fmt
 15
 16#include <linux/init.h>
 17#include <linux/perf_event.h>
 18#include <asm/firmware.h>
 19#include <asm/hvcall.h>
 20#include <asm/io.h>
 21
 22#include "hv-gpci.h"
 23#include "hv-common.h"
 24
 25/*
 26 * Example usage:
 27 *  perf stat -e 'hv_gpci/counter_info_version=3,offset=0,length=8,
 28 *		  secondary_index=0,starting_index=0xffffffff,request=0x10/' ...
 29 */
 30
 31/* u32 */
 32EVENT_DEFINE_RANGE_FORMAT(request, config, 0, 31);
 33/* u32 */
 34/*
 35 * Note that starting_index, phys_processor_idx, sibling_part_id,
 36 * hw_chip_id, partition_id all refer to the same bit range. They
 37 * are basically aliases for the starting_index. The specific alias
 38 * used depends on the event. See REQUEST_IDX_KIND in hv-gpci-requests.h
 39 */
 40EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 32, 63);
 41EVENT_DEFINE_RANGE_FORMAT_LITE(phys_processor_idx, config, 32, 63);
 42EVENT_DEFINE_RANGE_FORMAT_LITE(sibling_part_id, config, 32, 63);
 43EVENT_DEFINE_RANGE_FORMAT_LITE(hw_chip_id, config, 32, 63);
 44EVENT_DEFINE_RANGE_FORMAT_LITE(partition_id, config, 32, 63);
 45
 46/* u16 */
 47EVENT_DEFINE_RANGE_FORMAT(secondary_index, config1, 0, 15);
 48/* u8 */
 49EVENT_DEFINE_RANGE_FORMAT(counter_info_version, config1, 16, 23);
 50/* u8, bytes of data (1-8) */
 51EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31);
 52/* u32, byte offset */
 53EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63);
 54
 55static struct attribute *format_attrs[] = {
 56	&format_attr_request.attr,
 57	&format_attr_starting_index.attr,
 58	&format_attr_phys_processor_idx.attr,
 59	&format_attr_sibling_part_id.attr,
 60	&format_attr_hw_chip_id.attr,
 61	&format_attr_partition_id.attr,
 62	&format_attr_secondary_index.attr,
 63	&format_attr_counter_info_version.attr,
 64
 65	&format_attr_offset.attr,
 66	&format_attr_length.attr,
 67	NULL,
 68};
 69
 70static struct attribute_group format_group = {
 71	.name = "format",
 72	.attrs = format_attrs,
 73};
 74
 75static struct attribute_group event_group = {
 76	.name  = "events",
 77	.attrs = hv_gpci_event_attrs,
 78};
 79
 80#define HV_CAPS_ATTR(_name, _format)				\
 81static ssize_t _name##_show(struct device *dev,			\
 82			    struct device_attribute *attr,	\
 83			    char *page)				\
 84{								\
 85	struct hv_perf_caps caps;				\
 86	unsigned long hret = hv_perf_caps_get(&caps);		\
 87	if (hret)						\
 88		return -EIO;					\
 89								\
 90	return sprintf(page, _format, caps._name);		\
 91}								\
 92static struct device_attribute hv_caps_attr_##_name = __ATTR_RO(_name)
 93
 94static ssize_t kernel_version_show(struct device *dev,
 95				   struct device_attribute *attr,
 96				   char *page)
 97{
 98	return sprintf(page, "0x%x\n", COUNTER_INFO_VERSION_CURRENT);
 99}
100
101static DEVICE_ATTR_RO(kernel_version);
102HV_CAPS_ATTR(version, "0x%x\n");
103HV_CAPS_ATTR(ga, "%d\n");
104HV_CAPS_ATTR(expanded, "%d\n");
105HV_CAPS_ATTR(lab, "%d\n");
106HV_CAPS_ATTR(collect_privileged, "%d\n");
107
108static struct attribute *interface_attrs[] = {
109	&dev_attr_kernel_version.attr,
110	&hv_caps_attr_version.attr,
111	&hv_caps_attr_ga.attr,
112	&hv_caps_attr_expanded.attr,
113	&hv_caps_attr_lab.attr,
114	&hv_caps_attr_collect_privileged.attr,
115	NULL,
116};
117
118static struct attribute_group interface_group = {
119	.name = "interface",
120	.attrs = interface_attrs,
121};
122
123static const struct attribute_group *attr_groups[] = {
124	&format_group,
125	&event_group,
126	&interface_group,
127	NULL,
128};
129
130#define HGPCI_REQ_BUFFER_SIZE	4096
131#define HGPCI_MAX_DATA_BYTES \
132	(HGPCI_REQ_BUFFER_SIZE - sizeof(struct hv_get_perf_counter_info_params))
133
134static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
135
136struct hv_gpci_request_buffer {
137	struct hv_get_perf_counter_info_params params;
138	uint8_t bytes[HGPCI_MAX_DATA_BYTES];
139} __packed;
140
141static unsigned long single_gpci_request(u32 req, u32 starting_index,
142		u16 secondary_index, u8 version_in, u32 offset, u8 length,
143		u64 *value)
144{
145	unsigned long ret;
146	size_t i;
147	u64 count;
148	struct hv_gpci_request_buffer *arg;
149
150	arg = (void *)get_cpu_var(hv_gpci_reqb);
151	memset(arg, 0, HGPCI_REQ_BUFFER_SIZE);
152
153	arg->params.counter_request = cpu_to_be32(req);
154	arg->params.starting_index = cpu_to_be32(starting_index);
155	arg->params.secondary_index = cpu_to_be16(secondary_index);
156	arg->params.counter_info_version_in = version_in;
157
158	ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
159			virt_to_phys(arg), HGPCI_REQ_BUFFER_SIZE);
160	if (ret) {
161		pr_devel("hcall failed: 0x%lx\n", ret);
162		goto out;
163	}
164
165	/*
166	 * we verify offset and length are within the zeroed buffer at event
167	 * init.
168	 */
169	count = 0;
170	for (i = offset; i < offset + length; i++)
171		count |= arg->bytes[i] << (i - offset);
172
173	*value = count;
174out:
175	put_cpu_var(hv_gpci_reqb);
176	return ret;
177}
178
179static u64 h_gpci_get_value(struct perf_event *event)
180{
181	u64 count;
182	unsigned long ret = single_gpci_request(event_get_request(event),
183					event_get_starting_index(event),
184					event_get_secondary_index(event),
185					event_get_counter_info_version(event),
186					event_get_offset(event),
187					event_get_length(event),
188					&count);
189	if (ret)
190		return 0;
191	return count;
192}
193
194static void h_gpci_event_update(struct perf_event *event)
195{
196	s64 prev;
197	u64 now = h_gpci_get_value(event);
198	prev = local64_xchg(&event->hw.prev_count, now);
199	local64_add(now - prev, &event->count);
200}
201
202static void h_gpci_event_start(struct perf_event *event, int flags)
203{
204	local64_set(&event->hw.prev_count, h_gpci_get_value(event));
205}
206
207static void h_gpci_event_stop(struct perf_event *event, int flags)
208{
209	h_gpci_event_update(event);
210}
211
212static int h_gpci_event_add(struct perf_event *event, int flags)
213{
214	if (flags & PERF_EF_START)
215		h_gpci_event_start(event, flags);
216
217	return 0;
218}
219
220static int h_gpci_event_init(struct perf_event *event)
221{
222	u64 count;
223	u8 length;
224
225	/* Not our event */
226	if (event->attr.type != event->pmu->type)
227		return -ENOENT;
228
229	/* config2 is unused */
230	if (event->attr.config2) {
231		pr_devel("config2 set when reserved\n");
232		return -EINVAL;
233	}
234
235	/* unsupported modes and filters */
236	if (event->attr.exclude_user   ||
237	    event->attr.exclude_kernel ||
238	    event->attr.exclude_hv     ||
239	    event->attr.exclude_idle   ||
240	    event->attr.exclude_host   ||
241	    event->attr.exclude_guest)
242		return -EINVAL;
243
244	/* no branch sampling */
245	if (has_branch_stack(event))
246		return -EOPNOTSUPP;
247
248	length = event_get_length(event);
249	if (length < 1 || length > 8) {
250		pr_devel("length invalid\n");
251		return -EINVAL;
252	}
253
254	/* last byte within the buffer? */
255	if ((event_get_offset(event) + length) > HGPCI_MAX_DATA_BYTES) {
256		pr_devel("request outside of buffer: %zu > %zu\n",
257				(size_t)event_get_offset(event) + length,
258				HGPCI_MAX_DATA_BYTES);
259		return -EINVAL;
260	}
261
262	/* check if the request works... */
263	if (single_gpci_request(event_get_request(event),
264				event_get_starting_index(event),
265				event_get_secondary_index(event),
266				event_get_counter_info_version(event),
267				event_get_offset(event),
268				length,
269				&count)) {
270		pr_devel("gpci hcall failed\n");
271		return -EINVAL;
272	}
273
274	return 0;
275}
276
277static struct pmu h_gpci_pmu = {
278	.task_ctx_nr = perf_invalid_context,
279
280	.name = "hv_gpci",
281	.attr_groups = attr_groups,
282	.event_init  = h_gpci_event_init,
283	.add         = h_gpci_event_add,
284	.del         = h_gpci_event_stop,
285	.start       = h_gpci_event_start,
286	.stop        = h_gpci_event_stop,
287	.read        = h_gpci_event_update,
288};
289
290static int hv_gpci_init(void)
291{
292	int r;
293	unsigned long hret;
294	struct hv_perf_caps caps;
295
296	hv_gpci_assert_offsets_correct();
297
298	if (!firmware_has_feature(FW_FEATURE_LPAR)) {
299		pr_debug("not a virtualized system, not enabling\n");
300		return -ENODEV;
301	}
302
303	hret = hv_perf_caps_get(&caps);
304	if (hret) {
305		pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
306				hret);
307		return -ENODEV;
308	}
309
310	/* sampling not supported */
311	h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
312
313	r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
314	if (r)
315		return r;
316
317	return 0;
318}
319
320device_initcall(hv_gpci_init);