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 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
134 static DEFINE_PER_CPU(char, hv_gpci_reqb[HGPCI_REQ_BUFFER_SIZE]) __aligned(sizeof(uint64_t));
135
136 struct hv_gpci_request_buffer {
137 struct hv_get_perf_counter_info_params params;
138 uint8_t bytes[HGPCI_MAX_DATA_BYTES];
139 } __packed;
140
single_gpci_request(u32 req,u32 starting_index,u16 secondary_index,u8 version_in,u32 offset,u8 length,u64 * value)141 static 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;
174 out:
175 put_cpu_var(hv_gpci_reqb);
176 return ret;
177 }
178
h_gpci_get_value(struct perf_event * event)179 static 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
h_gpci_event_update(struct perf_event * event)194 static 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
h_gpci_event_start(struct perf_event * event,int flags)202 static 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
h_gpci_event_stop(struct perf_event * event,int flags)207 static void h_gpci_event_stop(struct perf_event *event, int flags)
208 {
209 h_gpci_event_update(event);
210 }
211
h_gpci_event_add(struct perf_event * event,int flags)212 static 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
h_gpci_event_init(struct perf_event * event)220 static 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
277 static 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
hv_gpci_init(void)290 static 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
320 device_initcall(hv_gpci_init);
321
