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 */
32 EVENT_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 */
40 EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 32, 63);
41 EVENT_DEFINE_RANGE_FORMAT_LITE(phys_processor_idx, config, 32, 63);
42 EVENT_DEFINE_RANGE_FORMAT_LITE(sibling_part_id, config, 32, 63);
43 EVENT_DEFINE_RANGE_FORMAT_LITE(hw_chip_id, config, 32, 63);
44 EVENT_DEFINE_RANGE_FORMAT_LITE(partition_id, config, 32, 63);
45
46 /* u16 */
47 EVENT_DEFINE_RANGE_FORMAT(secondary_index, config1, 0, 15);
48 /* u8 */
49 EVENT_DEFINE_RANGE_FORMAT(counter_info_version, config1, 16, 23);
50 /* u8, bytes of data (1-8) */
51 EVENT_DEFINE_RANGE_FORMAT(length, config1, 24, 31);
52 /* u32, byte offset */
53 EVENT_DEFINE_RANGE_FORMAT(offset, config1, 32, 63);
54
55 static 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
70 static struct attribute_group format_group = {
71 .name = "format",
72 .attrs = format_attrs,
73 };
74
75 static struct attribute_group event_group = {
76 .name = "events",
77 .attrs = hv_gpci_event_attrs,
78 };
79
80 #define HV_CAPS_ATTR(_name, _format) \
81 static 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 } \
92 static struct device_attribute hv_caps_attr_##_name = __ATTR_RO(_name)
93
kernel_version_show(struct device * dev,struct device_attribute * attr,char * page)94 static 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
101 static DEVICE_ATTR_RO(kernel_version);
102 HV_CAPS_ATTR(version, "0x%x\n");
103 HV_CAPS_ATTR(ga, "%d\n");
104 HV_CAPS_ATTR(expanded, "%d\n");
105 HV_CAPS_ATTR(lab, "%d\n");
106 HV_CAPS_ATTR(collect_privileged, "%d\n");
107
108 static 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
118 static struct attribute_group interface_group = {
119 .name = "interface",
120 .attrs = interface_attrs,
121 };
122
123 static const struct attribute_group *attr_groups[] = {
124 &format_group,
125 &event_group,
126 &interface_group,
127 NULL,
128 };
129
130 #define GPCI_MAX_DATA_BYTES \
131 (1024 - sizeof(struct hv_get_perf_counter_info_params))
132
single_gpci_request(u32 req,u32 starting_index,u16 secondary_index,u8 version_in,u32 offset,u8 length,u64 * value)133 static unsigned long single_gpci_request(u32 req, u32 starting_index,
134 u16 secondary_index, u8 version_in, u32 offset, u8 length,
135 u64 *value)
136 {
137 unsigned long ret;
138 size_t i;
139 u64 count;
140
141 struct {
142 struct hv_get_perf_counter_info_params params;
143 uint8_t bytes[GPCI_MAX_DATA_BYTES];
144 } __packed __aligned(sizeof(uint64_t)) arg = {
145 .params = {
146 .counter_request = cpu_to_be32(req),
147 .starting_index = cpu_to_be32(starting_index),
148 .secondary_index = cpu_to_be16(secondary_index),
149 .counter_info_version_in = version_in,
150 }
151 };
152
153 ret = plpar_hcall_norets(H_GET_PERF_COUNTER_INFO,
154 virt_to_phys(&arg), sizeof(arg));
155 if (ret) {
156 pr_devel("hcall failed: 0x%lx\n", ret);
157 return ret;
158 }
159
160 /*
161 * we verify offset and length are within the zeroed buffer at event
162 * init.
163 */
164 count = 0;
165 for (i = offset; i < offset + length; i++)
166 count |= arg.bytes[i] << (i - offset);
167
168 *value = count;
169 return ret;
170 }
171
h_gpci_get_value(struct perf_event * event)172 static u64 h_gpci_get_value(struct perf_event *event)
173 {
174 u64 count;
175 unsigned long ret = single_gpci_request(event_get_request(event),
176 event_get_starting_index(event),
177 event_get_secondary_index(event),
178 event_get_counter_info_version(event),
179 event_get_offset(event),
180 event_get_length(event),
181 &count);
182 if (ret)
183 return 0;
184 return count;
185 }
186
h_gpci_event_update(struct perf_event * event)187 static void h_gpci_event_update(struct perf_event *event)
188 {
189 s64 prev;
190 u64 now = h_gpci_get_value(event);
191 prev = local64_xchg(&event->hw.prev_count, now);
192 local64_add(now - prev, &event->count);
193 }
194
h_gpci_event_start(struct perf_event * event,int flags)195 static void h_gpci_event_start(struct perf_event *event, int flags)
196 {
197 local64_set(&event->hw.prev_count, h_gpci_get_value(event));
198 }
199
h_gpci_event_stop(struct perf_event * event,int flags)200 static void h_gpci_event_stop(struct perf_event *event, int flags)
201 {
202 h_gpci_event_update(event);
203 }
204
h_gpci_event_add(struct perf_event * event,int flags)205 static int h_gpci_event_add(struct perf_event *event, int flags)
206 {
207 if (flags & PERF_EF_START)
208 h_gpci_event_start(event, flags);
209
210 return 0;
211 }
212
h_gpci_event_init(struct perf_event * event)213 static int h_gpci_event_init(struct perf_event *event)
214 {
215 u64 count;
216 u8 length;
217
218 /* Not our event */
219 if (event->attr.type != event->pmu->type)
220 return -ENOENT;
221
222 /* config2 is unused */
223 if (event->attr.config2) {
224 pr_devel("config2 set when reserved\n");
225 return -EINVAL;
226 }
227
228 /* unsupported modes and filters */
229 if (event->attr.exclude_user ||
230 event->attr.exclude_kernel ||
231 event->attr.exclude_hv ||
232 event->attr.exclude_idle ||
233 event->attr.exclude_host ||
234 event->attr.exclude_guest)
235 return -EINVAL;
236
237 /* no branch sampling */
238 if (has_branch_stack(event))
239 return -EOPNOTSUPP;
240
241 length = event_get_length(event);
242 if (length < 1 || length > 8) {
243 pr_devel("length invalid\n");
244 return -EINVAL;
245 }
246
247 /* last byte within the buffer? */
248 if ((event_get_offset(event) + length) > GPCI_MAX_DATA_BYTES) {
249 pr_devel("request outside of buffer: %zu > %zu\n",
250 (size_t)event_get_offset(event) + length,
251 GPCI_MAX_DATA_BYTES);
252 return -EINVAL;
253 }
254
255 /* check if the request works... */
256 if (single_gpci_request(event_get_request(event),
257 event_get_starting_index(event),
258 event_get_secondary_index(event),
259 event_get_counter_info_version(event),
260 event_get_offset(event),
261 length,
262 &count)) {
263 pr_devel("gpci hcall failed\n");
264 return -EINVAL;
265 }
266
267 return 0;
268 }
269
270 static struct pmu h_gpci_pmu = {
271 .task_ctx_nr = perf_invalid_context,
272
273 .name = "hv_gpci",
274 .attr_groups = attr_groups,
275 .event_init = h_gpci_event_init,
276 .add = h_gpci_event_add,
277 .del = h_gpci_event_stop,
278 .start = h_gpci_event_start,
279 .stop = h_gpci_event_stop,
280 .read = h_gpci_event_update,
281 };
282
hv_gpci_init(void)283 static int hv_gpci_init(void)
284 {
285 int r;
286 unsigned long hret;
287 struct hv_perf_caps caps;
288
289 hv_gpci_assert_offsets_correct();
290
291 if (!firmware_has_feature(FW_FEATURE_LPAR)) {
292 pr_debug("not a virtualized system, not enabling\n");
293 return -ENODEV;
294 }
295
296 hret = hv_perf_caps_get(&caps);
297 if (hret) {
298 pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
299 hret);
300 return -ENODEV;
301 }
302
303 /* sampling not supported */
304 h_gpci_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
305
306 r = perf_pmu_register(&h_gpci_pmu, h_gpci_pmu.name, -1);
307 if (r)
308 return r;
309
310 return 0;
311 }
312
313 device_initcall(hv_gpci_init);
314