1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2014, Michael Ellerman, IBM Corp.
4 */
5
6 #define _GNU_SOURCE /* For CPU_ZERO etc. */
7
8 #include <sched.h>
9 #include <sys/wait.h>
10 #include <setjmp.h>
11 #include <signal.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <sys/ioctl.h>
16
17 #include "trace.h"
18 #include "ebb.h"
19
20
21 void (*ebb_user_func)(void);
22
23 void ebb_hook(void)
24 {
25 if (ebb_user_func)
26 ebb_user_func();
27 }
28
29 struct ebb_state ebb_state;
30
31 u64 sample_period = 0x40000000ull;
32
33 void reset_ebb_with_clear_mask(unsigned long mmcr0_clear_mask)
34 {
35 u64 val;
36
37 /* 2) clear MMCR0[PMAO] - docs say BESCR[PMEO] should do this */
38 /* 3) set MMCR0[PMAE] - docs say BESCR[PME] should do this */
39 val = mfspr(SPRN_MMCR0);
40 mtspr(SPRN_MMCR0, (val & ~mmcr0_clear_mask) | MMCR0_PMAE);
41
42 /* 4) clear BESCR[PMEO] */
43 mtspr(SPRN_BESCRR, BESCR_PMEO);
44
45 /* 5) set BESCR[PME] */
46 mtspr(SPRN_BESCRS, BESCR_PME);
47
48 /* 6) rfebb 1 - done in our caller */
49 }
50
51 void reset_ebb(void)
52 {
53 reset_ebb_with_clear_mask(MMCR0_PMAO | MMCR0_FC);
54 }
55
56 /* Called outside of the EBB handler to check MMCR0 is sane */
57 int ebb_check_mmcr0(void)
58 {
59 u64 val;
60
61 val = mfspr(SPRN_MMCR0);
62 if ((val & (MMCR0_FC | MMCR0_PMAO)) == MMCR0_FC) {
63 /* It's OK if we see FC & PMAO, but not FC by itself */
64 printf("Outside of loop, only FC set 0x%llx\n", val);
65 return 1;
66 }
67
68 return 0;
69 }
70
71 bool ebb_check_count(int pmc, u64 sample_period, int fudge)
72 {
73 u64 count, upper, lower;
74
75 count = ebb_state.stats.pmc_count[PMC_INDEX(pmc)];
76
77 lower = ebb_state.stats.ebb_count * (sample_period - fudge);
78
79 if (count < lower) {
80 printf("PMC%d count (0x%llx) below lower limit 0x%llx (-0x%llx)\n",
81 pmc, count, lower, lower - count);
82 return false;
83 }
84
85 upper = ebb_state.stats.ebb_count * (sample_period + fudge);
86
87 if (count > upper) {
88 printf("PMC%d count (0x%llx) above upper limit 0x%llx (+0x%llx)\n",
89 pmc, count, upper, count - upper);
90 return false;
91 }
92
93 printf("PMC%d count (0x%llx) is between 0x%llx and 0x%llx delta +0x%llx/-0x%llx\n",
94 pmc, count, lower, upper, count - lower, upper - count);
95
96 return true;
97 }
98
99 void standard_ebb_callee(void)
100 {
101 int found, i;
102 u64 val;
103
104 val = mfspr(SPRN_BESCR);
105 if (!(val & BESCR_PMEO)) {
106 ebb_state.stats.spurious++;
107 goto out;
108 }
109
110 ebb_state.stats.ebb_count++;
111 trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count);
112
113 val = mfspr(SPRN_MMCR0);
114 trace_log_reg(ebb_state.trace, SPRN_MMCR0, val);
115
116 found = 0;
117 for (i = 1; i <= 6; i++) {
118 if (ebb_state.pmc_enable[PMC_INDEX(i)])
119 found += count_pmc(i, sample_period);
120 }
121
122 if (!found)
123 ebb_state.stats.no_overflow++;
124
125 out:
126 reset_ebb();
127 }
128
129 extern void ebb_handler(void);
130
131 void setup_ebb_handler(void (*callee)(void))
132 {
133 u64 entry;
134
135 #if defined(_CALL_ELF) && _CALL_ELF == 2
136 entry = (u64)ebb_handler;
137 #else
138 struct opd
139 {
140 u64 entry;
141 u64 toc;
142 } *opd;
143
144 opd = (struct opd *)ebb_handler;
145 entry = opd->entry;
146 #endif
147 printf("EBB Handler is at %#llx\n", entry);
148
149 ebb_user_func = callee;
150
151 /* Ensure ebb_user_func is set before we set the handler */
152 mb();
153 mtspr(SPRN_EBBHR, entry);
154
155 /* Make sure the handler is set before we return */
156 mb();
157 }
158
159 void clear_ebb_stats(void)
160 {
161 memset(&ebb_state.stats, 0, sizeof(ebb_state.stats));
162 }
163
164 void dump_summary_ebb_state(void)
165 {
166 printf("ebb_state:\n" \
167 " ebb_count = %d\n" \
168 " spurious = %d\n" \
169 " negative = %d\n" \
170 " no_overflow = %d\n" \
171 " pmc[1] count = 0x%llx\n" \
172 " pmc[2] count = 0x%llx\n" \
173 " pmc[3] count = 0x%llx\n" \
174 " pmc[4] count = 0x%llx\n" \
175 " pmc[5] count = 0x%llx\n" \
176 " pmc[6] count = 0x%llx\n",
177 ebb_state.stats.ebb_count, ebb_state.stats.spurious,
178 ebb_state.stats.negative, ebb_state.stats.no_overflow,
179 ebb_state.stats.pmc_count[0], ebb_state.stats.pmc_count[1],
180 ebb_state.stats.pmc_count[2], ebb_state.stats.pmc_count[3],
181 ebb_state.stats.pmc_count[4], ebb_state.stats.pmc_count[5]);
182 }
183
184 static char *decode_mmcr0(u32 value)
185 {
186 static char buf[16];
187
188 buf[0] = '\0';
189
190 if (value & (1 << 31))
191 strcat(buf, "FC ");
192 if (value & (1 << 26))
193 strcat(buf, "PMAE ");
194 if (value & (1 << 7))
195 strcat(buf, "PMAO ");
196
197 return buf;
198 }
199
200 static char *decode_bescr(u64 value)
201 {
202 static char buf[16];
203
204 buf[0] = '\0';
205
206 if (value & (1ull << 63))
207 strcat(buf, "GE ");
208 if (value & (1ull << 32))
209 strcat(buf, "PMAE ");
210 if (value & 1)
211 strcat(buf, "PMAO ");
212
213 return buf;
214 }
215
216 void dump_ebb_hw_state(void)
217 {
218 u64 bescr;
219 u32 mmcr0;
220
221 mmcr0 = mfspr(SPRN_MMCR0);
222 bescr = mfspr(SPRN_BESCR);
223
224 printf("HW state:\n" \
225 "MMCR0 0x%016x %s\n" \
226 "MMCR2 0x%016lx\n" \
227 "EBBHR 0x%016lx\n" \
228 "BESCR 0x%016llx %s\n" \
229 "PMC1 0x%016lx\n" \
230 "PMC2 0x%016lx\n" \
231 "PMC3 0x%016lx\n" \
232 "PMC4 0x%016lx\n" \
233 "PMC5 0x%016lx\n" \
234 "PMC6 0x%016lx\n" \
235 "SIAR 0x%016lx\n",
236 mmcr0, decode_mmcr0(mmcr0), mfspr(SPRN_MMCR2),
237 mfspr(SPRN_EBBHR), bescr, decode_bescr(bescr),
238 mfspr(SPRN_PMC1), mfspr(SPRN_PMC2), mfspr(SPRN_PMC3),
239 mfspr(SPRN_PMC4), mfspr(SPRN_PMC5), mfspr(SPRN_PMC6),
240 mfspr(SPRN_SIAR));
241 }
242
243 void dump_ebb_state(void)
244 {
245 dump_summary_ebb_state();
246
247 dump_ebb_hw_state();
248
249 trace_buffer_print(ebb_state.trace);
250 }
251
252 int count_pmc(int pmc, uint32_t sample_period)
253 {
254 uint32_t start_value;
255 u64 val;
256
257 /* 0) Read PMC */
258 start_value = pmc_sample_period(sample_period);
259
260 val = read_pmc(pmc);
261 if (val < start_value)
262 ebb_state.stats.negative++;
263 else
264 ebb_state.stats.pmc_count[PMC_INDEX(pmc)] += val - start_value;
265
266 trace_log_reg(ebb_state.trace, SPRN_PMC1 + pmc - 1, val);
267
268 /* 1) Reset PMC */
269 write_pmc(pmc, start_value);
270
271 /* Report if we overflowed */
272 return val >= COUNTER_OVERFLOW;
273 }
274
275 int ebb_event_enable(struct event *e)
276 {
277 int rc;
278
279 /* Ensure any SPR writes are ordered vs us */
280 mb();
281
282 rc = ioctl(e->fd, PERF_EVENT_IOC_ENABLE);
283 if (rc)
284 return rc;
285
286 rc = event_read(e);
287
288 /* Ditto */
289 mb();
290
291 return rc;
292 }
293
294 void ebb_freeze_pmcs(void)
295 {
296 mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC);
297 mb();
298 }
299
300 void ebb_unfreeze_pmcs(void)
301 {
302 /* Unfreeze counters */
303 mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC);
304 mb();
305 }
306
307 void ebb_global_enable(void)
308 {
309 /* Enable EBBs globally and PMU EBBs */
310 mtspr(SPRN_BESCR, 0x8000000100000000ull);
311 mb();
312 }
313
314 void ebb_global_disable(void)
315 {
316 /* Disable EBBs & freeze counters, events are still scheduled */
317 mtspr(SPRN_BESCRR, BESCR_PME);
318 mb();
319 }
320
321 bool ebb_is_supported(void)
322 {
323 #ifdef PPC_FEATURE2_EBB
324 /* EBB requires at least POWER8 */
325 return have_hwcap2(PPC_FEATURE2_EBB);
326 #else
327 return false;
328 #endif
329 }
330
331 void event_ebb_init(struct event *e)
332 {
333 e->attr.config |= (1ull << 63);
334 }
335
336 void event_bhrb_init(struct event *e, unsigned ifm)
337 {
338 e->attr.config |= (1ull << 62) | ((u64)ifm << 60);
339 }
340
341 void event_leader_ebb_init(struct event *e)
342 {
343 event_ebb_init(e);
344
345 e->attr.exclusive = 1;
346 e->attr.pinned = 1;
347 }
348
349 int ebb_child(union pipe read_pipe, union pipe write_pipe)
350 {
351 struct event event;
352 uint64_t val;
353
354 FAIL_IF(wait_for_parent(read_pipe));
355
356 event_init_named(&event, 0x1001e, "cycles");
357 event_leader_ebb_init(&event);
358
359 event.attr.exclude_kernel = 1;
360 event.attr.exclude_hv = 1;
361 event.attr.exclude_idle = 1;
362
363 FAIL_IF(event_open(&event));
364
365 ebb_enable_pmc_counting(1);
366 setup_ebb_handler(standard_ebb_callee);
367 ebb_global_enable();
368
369 FAIL_IF(event_enable(&event));
370
371 if (event_read(&event)) {
372 /*
373 * Some tests expect to fail here, so don't report an error on
374 * this line, and return a distinguisable error code. Tell the
375 * parent an error happened.
376 */
377 notify_parent_of_error(write_pipe);
378 return 2;
379 }
380
381 mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
382
383 FAIL_IF(notify_parent(write_pipe));
384 FAIL_IF(wait_for_parent(read_pipe));
385 FAIL_IF(notify_parent(write_pipe));
386
387 while (ebb_state.stats.ebb_count < 20) {
388 FAIL_IF(core_busy_loop());
389
390 /* To try and hit SIGILL case */
391 val = mfspr(SPRN_MMCRA);
392 val |= mfspr(SPRN_MMCR2);
393 val |= mfspr(SPRN_MMCR0);
394 }
395
396 ebb_global_disable();
397 ebb_freeze_pmcs();
398
399 dump_ebb_state();
400
401 event_close(&event);
402
403 FAIL_IF(ebb_state.stats.ebb_count == 0);
404
405 return 0;
406 }
407
408 static jmp_buf setjmp_env;
409
410 static void sigill_handler(int signal)
411 {
412 printf("Took sigill\n");
413 longjmp(setjmp_env, 1);
414 }
415
416 static struct sigaction sigill_action = {
417 .sa_handler = sigill_handler,
418 };
419
420 int catch_sigill(void (*func)(void))
421 {
422 if (sigaction(SIGILL, &sigill_action, NULL)) {
423 perror("sigaction");
424 return 1;
425 }
426
427 if (setjmp(setjmp_env) == 0) {
428 func();
429 return 1;
430 }
431
432 return 0;
433 }
434
435 void write_pmc1(void)
436 {
437 mtspr(SPRN_PMC1, 0);
438 }
439
440 void write_pmc(int pmc, u64 value)
441 {
442 switch (pmc) {
443 case 1: mtspr(SPRN_PMC1, value); break;
444 case 2: mtspr(SPRN_PMC2, value); break;
445 case 3: mtspr(SPRN_PMC3, value); break;
446 case 4: mtspr(SPRN_PMC4, value); break;
447 case 5: mtspr(SPRN_PMC5, value); break;
448 case 6: mtspr(SPRN_PMC6, value); break;
449 }
450 }
451
452 u64 read_pmc(int pmc)
453 {
454 switch (pmc) {
455 case 1: return mfspr(SPRN_PMC1);
456 case 2: return mfspr(SPRN_PMC2);
457 case 3: return mfspr(SPRN_PMC3);
458 case 4: return mfspr(SPRN_PMC4);
459 case 5: return mfspr(SPRN_PMC5);
460 case 6: return mfspr(SPRN_PMC6);
461 }
462
463 return 0;
464 }
465
466 static void term_handler(int signal)
467 {
468 dump_summary_ebb_state();
469 dump_ebb_hw_state();
470 abort();
471 }
472
473 struct sigaction term_action = {
474 .sa_handler = term_handler,
475 };
476
477 static void __attribute__((constructor)) ebb_init(void)
478 {
479 clear_ebb_stats();
480
481 if (sigaction(SIGTERM, &term_action, NULL))
482 perror("sigaction");
483
484 ebb_state.trace = trace_buffer_allocate(1 * 1024 * 1024);
485 }
486
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