1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ARMv6 Performance counter handling code.
4 *
5 * Copyright (C) 2009 picoChip Designs, Ltd., Jamie Iles
6 *
7 * ARMv6 has 2 configurable performance counters and a single cycle counter.
8 * They all share a single reset bit but can be written to zero so we can use
9 * that for a reset.
10 *
11 * The counters can't be individually enabled or disabled so when we remove
12 * one event and replace it with another we could get spurious counts from the
13 * wrong event. However, we can take advantage of the fact that the
14 * performance counters can export events to the event bus, and the event bus
15 * itself can be monitored. This requires that we *don't* export the events to
16 * the event bus. The procedure for disabling a configurable counter is:
17 * - change the counter to count the ETMEXTOUT[0] signal (0x20). This
18 * effectively stops the counter from counting.
19 * - disable the counter's interrupt generation (each counter has it's
20 * own interrupt enable bit).
21 * Once stopped, the counter value can be written as 0 to reset.
22 *
23 * To enable a counter:
24 * - enable the counter's interrupt generation.
25 * - set the new event type.
26 *
27 * Note: the dedicated cycle counter only counts cycles and can't be
28 * enabled/disabled independently of the others. When we want to disable the
29 * cycle counter, we have to just disable the interrupt reporting and start
30 * ignoring that counter. When re-enabling, we have to reset the value and
31 * enable the interrupt.
32 */
33
34 #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K)
35
36 #include <asm/cputype.h>
37 #include <asm/irq_regs.h>
38
39 #include <linux/of.h>
40 #include <linux/perf/arm_pmu.h>
41 #include <linux/platform_device.h>
42
43 enum armv6_perf_types {
44 ARMV6_PERFCTR_ICACHE_MISS = 0x0,
45 ARMV6_PERFCTR_IBUF_STALL = 0x1,
46 ARMV6_PERFCTR_DDEP_STALL = 0x2,
47 ARMV6_PERFCTR_ITLB_MISS = 0x3,
48 ARMV6_PERFCTR_DTLB_MISS = 0x4,
49 ARMV6_PERFCTR_BR_EXEC = 0x5,
50 ARMV6_PERFCTR_BR_MISPREDICT = 0x6,
51 ARMV6_PERFCTR_INSTR_EXEC = 0x7,
52 ARMV6_PERFCTR_DCACHE_HIT = 0x9,
53 ARMV6_PERFCTR_DCACHE_ACCESS = 0xA,
54 ARMV6_PERFCTR_DCACHE_MISS = 0xB,
55 ARMV6_PERFCTR_DCACHE_WBACK = 0xC,
56 ARMV6_PERFCTR_SW_PC_CHANGE = 0xD,
57 ARMV6_PERFCTR_MAIN_TLB_MISS = 0xF,
58 ARMV6_PERFCTR_EXPL_D_ACCESS = 0x10,
59 ARMV6_PERFCTR_LSU_FULL_STALL = 0x11,
60 ARMV6_PERFCTR_WBUF_DRAINED = 0x12,
61 ARMV6_PERFCTR_CPU_CYCLES = 0xFF,
62 ARMV6_PERFCTR_NOP = 0x20,
63 };
64
65 enum armv6_counters {
66 ARMV6_CYCLE_COUNTER = 0,
67 ARMV6_COUNTER0,
68 ARMV6_COUNTER1,
69 };
70
71 /*
72 * The hardware events that we support. We do support cache operations but
73 * we have harvard caches and no way to combine instruction and data
74 * accesses/misses in hardware.
75 */
76 static const unsigned armv6_perf_map[PERF_COUNT_HW_MAX] = {
77 PERF_MAP_ALL_UNSUPPORTED,
78 [PERF_COUNT_HW_CPU_CYCLES] = ARMV6_PERFCTR_CPU_CYCLES,
79 [PERF_COUNT_HW_INSTRUCTIONS] = ARMV6_PERFCTR_INSTR_EXEC,
80 [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = ARMV6_PERFCTR_BR_EXEC,
81 [PERF_COUNT_HW_BRANCH_MISSES] = ARMV6_PERFCTR_BR_MISPREDICT,
82 [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = ARMV6_PERFCTR_IBUF_STALL,
83 [PERF_COUNT_HW_STALLED_CYCLES_BACKEND] = ARMV6_PERFCTR_LSU_FULL_STALL,
84 };
85
86 static const unsigned armv6_perf_cache_map[PERF_COUNT_HW_CACHE_MAX]
87 [PERF_COUNT_HW_CACHE_OP_MAX]
88 [PERF_COUNT_HW_CACHE_RESULT_MAX] = {
89 PERF_CACHE_MAP_ALL_UNSUPPORTED,
90
91 /*
92 * The performance counters don't differentiate between read and write
93 * accesses/misses so this isn't strictly correct, but it's the best we
94 * can do. Writes and reads get combined.
95 */
96 [C(L1D)][C(OP_READ)][C(RESULT_ACCESS)] = ARMV6_PERFCTR_DCACHE_ACCESS,
97 [C(L1D)][C(OP_READ)][C(RESULT_MISS)] = ARMV6_PERFCTR_DCACHE_MISS,
98 [C(L1D)][C(OP_WRITE)][C(RESULT_ACCESS)] = ARMV6_PERFCTR_DCACHE_ACCESS,
99 [C(L1D)][C(OP_WRITE)][C(RESULT_MISS)] = ARMV6_PERFCTR_DCACHE_MISS,
100
101 [C(L1I)][C(OP_READ)][C(RESULT_MISS)] = ARMV6_PERFCTR_ICACHE_MISS,
102
103 /*
104 * The ARM performance counters can count micro DTLB misses, micro ITLB
105 * misses and main TLB misses. There isn't an event for TLB misses, so
106 * use the micro misses here and if users want the main TLB misses they
107 * can use a raw counter.
108 */
109 [C(DTLB)][C(OP_READ)][C(RESULT_MISS)] = ARMV6_PERFCTR_DTLB_MISS,
110 [C(DTLB)][C(OP_WRITE)][C(RESULT_MISS)] = ARMV6_PERFCTR_DTLB_MISS,
111
112 [C(ITLB)][C(OP_READ)][C(RESULT_MISS)] = ARMV6_PERFCTR_ITLB_MISS,
113 [C(ITLB)][C(OP_WRITE)][C(RESULT_MISS)] = ARMV6_PERFCTR_ITLB_MISS,
114 };
115
116 static inline unsigned long
armv6_pmcr_read(void)117 armv6_pmcr_read(void)
118 {
119 u32 val;
120 asm volatile("mrc p15, 0, %0, c15, c12, 0" : "=r"(val));
121 return val;
122 }
123
124 static inline void
armv6_pmcr_write(unsigned long val)125 armv6_pmcr_write(unsigned long val)
126 {
127 asm volatile("mcr p15, 0, %0, c15, c12, 0" : : "r"(val));
128 }
129
130 #define ARMV6_PMCR_ENABLE (1 << 0)
131 #define ARMV6_PMCR_CTR01_RESET (1 << 1)
132 #define ARMV6_PMCR_CCOUNT_RESET (1 << 2)
133 #define ARMV6_PMCR_CCOUNT_DIV (1 << 3)
134 #define ARMV6_PMCR_COUNT0_IEN (1 << 4)
135 #define ARMV6_PMCR_COUNT1_IEN (1 << 5)
136 #define ARMV6_PMCR_CCOUNT_IEN (1 << 6)
137 #define ARMV6_PMCR_COUNT0_OVERFLOW (1 << 8)
138 #define ARMV6_PMCR_COUNT1_OVERFLOW (1 << 9)
139 #define ARMV6_PMCR_CCOUNT_OVERFLOW (1 << 10)
140 #define ARMV6_PMCR_EVT_COUNT0_SHIFT 20
141 #define ARMV6_PMCR_EVT_COUNT0_MASK (0xFF << ARMV6_PMCR_EVT_COUNT0_SHIFT)
142 #define ARMV6_PMCR_EVT_COUNT1_SHIFT 12
143 #define ARMV6_PMCR_EVT_COUNT1_MASK (0xFF << ARMV6_PMCR_EVT_COUNT1_SHIFT)
144
145 #define ARMV6_PMCR_OVERFLOWED_MASK \
146 (ARMV6_PMCR_COUNT0_OVERFLOW | ARMV6_PMCR_COUNT1_OVERFLOW | \
147 ARMV6_PMCR_CCOUNT_OVERFLOW)
148
149 static inline int
armv6_pmcr_has_overflowed(unsigned long pmcr)150 armv6_pmcr_has_overflowed(unsigned long pmcr)
151 {
152 return pmcr & ARMV6_PMCR_OVERFLOWED_MASK;
153 }
154
155 static inline int
armv6_pmcr_counter_has_overflowed(unsigned long pmcr,enum armv6_counters counter)156 armv6_pmcr_counter_has_overflowed(unsigned long pmcr,
157 enum armv6_counters counter)
158 {
159 int ret = 0;
160
161 if (ARMV6_CYCLE_COUNTER == counter)
162 ret = pmcr & ARMV6_PMCR_CCOUNT_OVERFLOW;
163 else if (ARMV6_COUNTER0 == counter)
164 ret = pmcr & ARMV6_PMCR_COUNT0_OVERFLOW;
165 else if (ARMV6_COUNTER1 == counter)
166 ret = pmcr & ARMV6_PMCR_COUNT1_OVERFLOW;
167 else
168 WARN_ONCE(1, "invalid counter number (%d)\n", counter);
169
170 return ret;
171 }
172
armv6pmu_read_counter(struct perf_event * event)173 static inline u64 armv6pmu_read_counter(struct perf_event *event)
174 {
175 struct hw_perf_event *hwc = &event->hw;
176 int counter = hwc->idx;
177 unsigned long value = 0;
178
179 if (ARMV6_CYCLE_COUNTER == counter)
180 asm volatile("mrc p15, 0, %0, c15, c12, 1" : "=r"(value));
181 else if (ARMV6_COUNTER0 == counter)
182 asm volatile("mrc p15, 0, %0, c15, c12, 2" : "=r"(value));
183 else if (ARMV6_COUNTER1 == counter)
184 asm volatile("mrc p15, 0, %0, c15, c12, 3" : "=r"(value));
185 else
186 WARN_ONCE(1, "invalid counter number (%d)\n", counter);
187
188 return value;
189 }
190
armv6pmu_write_counter(struct perf_event * event,u64 value)191 static inline void armv6pmu_write_counter(struct perf_event *event, u64 value)
192 {
193 struct hw_perf_event *hwc = &event->hw;
194 int counter = hwc->idx;
195
196 if (ARMV6_CYCLE_COUNTER == counter)
197 asm volatile("mcr p15, 0, %0, c15, c12, 1" : : "r"(value));
198 else if (ARMV6_COUNTER0 == counter)
199 asm volatile("mcr p15, 0, %0, c15, c12, 2" : : "r"(value));
200 else if (ARMV6_COUNTER1 == counter)
201 asm volatile("mcr p15, 0, %0, c15, c12, 3" : : "r"(value));
202 else
203 WARN_ONCE(1, "invalid counter number (%d)\n", counter);
204 }
205
armv6pmu_enable_event(struct perf_event * event)206 static void armv6pmu_enable_event(struct perf_event *event)
207 {
208 unsigned long val, mask, evt;
209 struct hw_perf_event *hwc = &event->hw;
210 int idx = hwc->idx;
211
212 if (ARMV6_CYCLE_COUNTER == idx) {
213 mask = 0;
214 evt = ARMV6_PMCR_CCOUNT_IEN;
215 } else if (ARMV6_COUNTER0 == idx) {
216 mask = ARMV6_PMCR_EVT_COUNT0_MASK;
217 evt = (hwc->config_base << ARMV6_PMCR_EVT_COUNT0_SHIFT) |
218 ARMV6_PMCR_COUNT0_IEN;
219 } else if (ARMV6_COUNTER1 == idx) {
220 mask = ARMV6_PMCR_EVT_COUNT1_MASK;
221 evt = (hwc->config_base << ARMV6_PMCR_EVT_COUNT1_SHIFT) |
222 ARMV6_PMCR_COUNT1_IEN;
223 } else {
224 WARN_ONCE(1, "invalid counter number (%d)\n", idx);
225 return;
226 }
227
228 /*
229 * Mask out the current event and set the counter to count the event
230 * that we're interested in.
231 */
232 val = armv6_pmcr_read();
233 val &= ~mask;
234 val |= evt;
235 armv6_pmcr_write(val);
236 }
237
238 static irqreturn_t
armv6pmu_handle_irq(struct arm_pmu * cpu_pmu)239 armv6pmu_handle_irq(struct arm_pmu *cpu_pmu)
240 {
241 unsigned long pmcr = armv6_pmcr_read();
242 struct perf_sample_data data;
243 struct pmu_hw_events *cpuc = this_cpu_ptr(cpu_pmu->hw_events);
244 struct pt_regs *regs;
245 int idx;
246
247 if (!armv6_pmcr_has_overflowed(pmcr))
248 return IRQ_NONE;
249
250 regs = get_irq_regs();
251
252 /*
253 * The interrupts are cleared by writing the overflow flags back to
254 * the control register. All of the other bits don't have any effect
255 * if they are rewritten, so write the whole value back.
256 */
257 armv6_pmcr_write(pmcr);
258
259 for (idx = 0; idx < cpu_pmu->num_events; ++idx) {
260 struct perf_event *event = cpuc->events[idx];
261 struct hw_perf_event *hwc;
262
263 /* Ignore if we don't have an event. */
264 if (!event)
265 continue;
266
267 /*
268 * We have a single interrupt for all counters. Check that
269 * each counter has overflowed before we process it.
270 */
271 if (!armv6_pmcr_counter_has_overflowed(pmcr, idx))
272 continue;
273
274 hwc = &event->hw;
275 armpmu_event_update(event);
276 perf_sample_data_init(&data, 0, hwc->last_period);
277 if (!armpmu_event_set_period(event))
278 continue;
279
280 if (perf_event_overflow(event, &data, regs))
281 cpu_pmu->disable(event);
282 }
283
284 /*
285 * Handle the pending perf events.
286 *
287 * Note: this call *must* be run with interrupts disabled. For
288 * platforms that can have the PMU interrupts raised as an NMI, this
289 * will not work.
290 */
291 irq_work_run();
292
293 return IRQ_HANDLED;
294 }
295
armv6pmu_start(struct arm_pmu * cpu_pmu)296 static void armv6pmu_start(struct arm_pmu *cpu_pmu)
297 {
298 unsigned long val;
299
300 val = armv6_pmcr_read();
301 val |= ARMV6_PMCR_ENABLE;
302 armv6_pmcr_write(val);
303 }
304
armv6pmu_stop(struct arm_pmu * cpu_pmu)305 static void armv6pmu_stop(struct arm_pmu *cpu_pmu)
306 {
307 unsigned long val;
308
309 val = armv6_pmcr_read();
310 val &= ~ARMV6_PMCR_ENABLE;
311 armv6_pmcr_write(val);
312 }
313
314 static int
armv6pmu_get_event_idx(struct pmu_hw_events * cpuc,struct perf_event * event)315 armv6pmu_get_event_idx(struct pmu_hw_events *cpuc,
316 struct perf_event *event)
317 {
318 struct hw_perf_event *hwc = &event->hw;
319 /* Always place a cycle counter into the cycle counter. */
320 if (ARMV6_PERFCTR_CPU_CYCLES == hwc->config_base) {
321 if (test_and_set_bit(ARMV6_CYCLE_COUNTER, cpuc->used_mask))
322 return -EAGAIN;
323
324 return ARMV6_CYCLE_COUNTER;
325 } else {
326 /*
327 * For anything other than a cycle counter, try and use
328 * counter0 and counter1.
329 */
330 if (!test_and_set_bit(ARMV6_COUNTER1, cpuc->used_mask))
331 return ARMV6_COUNTER1;
332
333 if (!test_and_set_bit(ARMV6_COUNTER0, cpuc->used_mask))
334 return ARMV6_COUNTER0;
335
336 /* The counters are all in use. */
337 return -EAGAIN;
338 }
339 }
340
armv6pmu_clear_event_idx(struct pmu_hw_events * cpuc,struct perf_event * event)341 static void armv6pmu_clear_event_idx(struct pmu_hw_events *cpuc,
342 struct perf_event *event)
343 {
344 clear_bit(event->hw.idx, cpuc->used_mask);
345 }
346
armv6pmu_disable_event(struct perf_event * event)347 static void armv6pmu_disable_event(struct perf_event *event)
348 {
349 unsigned long val, mask, evt;
350 struct hw_perf_event *hwc = &event->hw;
351 int idx = hwc->idx;
352
353 if (ARMV6_CYCLE_COUNTER == idx) {
354 mask = ARMV6_PMCR_CCOUNT_IEN;
355 evt = 0;
356 } else if (ARMV6_COUNTER0 == idx) {
357 mask = ARMV6_PMCR_COUNT0_IEN | ARMV6_PMCR_EVT_COUNT0_MASK;
358 evt = ARMV6_PERFCTR_NOP << ARMV6_PMCR_EVT_COUNT0_SHIFT;
359 } else if (ARMV6_COUNTER1 == idx) {
360 mask = ARMV6_PMCR_COUNT1_IEN | ARMV6_PMCR_EVT_COUNT1_MASK;
361 evt = ARMV6_PERFCTR_NOP << ARMV6_PMCR_EVT_COUNT1_SHIFT;
362 } else {
363 WARN_ONCE(1, "invalid counter number (%d)\n", idx);
364 return;
365 }
366
367 /*
368 * Mask out the current event and set the counter to count the number
369 * of ETM bus signal assertion cycles. The external reporting should
370 * be disabled and so this should never increment.
371 */
372 val = armv6_pmcr_read();
373 val &= ~mask;
374 val |= evt;
375 armv6_pmcr_write(val);
376 }
377
armv6_map_event(struct perf_event * event)378 static int armv6_map_event(struct perf_event *event)
379 {
380 return armpmu_map_event(event, &armv6_perf_map,
381 &armv6_perf_cache_map, 0xFF);
382 }
383
armv6pmu_init(struct arm_pmu * cpu_pmu)384 static void armv6pmu_init(struct arm_pmu *cpu_pmu)
385 {
386 cpu_pmu->handle_irq = armv6pmu_handle_irq;
387 cpu_pmu->enable = armv6pmu_enable_event;
388 cpu_pmu->disable = armv6pmu_disable_event;
389 cpu_pmu->read_counter = armv6pmu_read_counter;
390 cpu_pmu->write_counter = armv6pmu_write_counter;
391 cpu_pmu->get_event_idx = armv6pmu_get_event_idx;
392 cpu_pmu->clear_event_idx = armv6pmu_clear_event_idx;
393 cpu_pmu->start = armv6pmu_start;
394 cpu_pmu->stop = armv6pmu_stop;
395 cpu_pmu->map_event = armv6_map_event;
396 cpu_pmu->num_events = 3;
397 }
398
armv6_1136_pmu_init(struct arm_pmu * cpu_pmu)399 static int armv6_1136_pmu_init(struct arm_pmu *cpu_pmu)
400 {
401 armv6pmu_init(cpu_pmu);
402 cpu_pmu->name = "armv6_1136";
403 return 0;
404 }
405
armv6_1156_pmu_init(struct arm_pmu * cpu_pmu)406 static int armv6_1156_pmu_init(struct arm_pmu *cpu_pmu)
407 {
408 armv6pmu_init(cpu_pmu);
409 cpu_pmu->name = "armv6_1156";
410 return 0;
411 }
412
armv6_1176_pmu_init(struct arm_pmu * cpu_pmu)413 static int armv6_1176_pmu_init(struct arm_pmu *cpu_pmu)
414 {
415 armv6pmu_init(cpu_pmu);
416 cpu_pmu->name = "armv6_1176";
417 return 0;
418 }
419
420 static const struct of_device_id armv6_pmu_of_device_ids[] = {
421 {.compatible = "arm,arm1176-pmu", .data = armv6_1176_pmu_init},
422 {.compatible = "arm,arm1136-pmu", .data = armv6_1136_pmu_init},
423 { /* sentinel value */ }
424 };
425
426 static const struct pmu_probe_info armv6_pmu_probe_table[] = {
427 ARM_PMU_PROBE(ARM_CPU_PART_ARM1136, armv6_1136_pmu_init),
428 ARM_PMU_PROBE(ARM_CPU_PART_ARM1156, armv6_1156_pmu_init),
429 ARM_PMU_PROBE(ARM_CPU_PART_ARM1176, armv6_1176_pmu_init),
430 { /* sentinel value */ }
431 };
432
armv6_pmu_device_probe(struct platform_device * pdev)433 static int armv6_pmu_device_probe(struct platform_device *pdev)
434 {
435 return arm_pmu_device_probe(pdev, armv6_pmu_of_device_ids,
436 armv6_pmu_probe_table);
437 }
438
439 static struct platform_driver armv6_pmu_driver = {
440 .driver = {
441 .name = "armv6-pmu",
442 .of_match_table = armv6_pmu_of_device_ids,
443 },
444 .probe = armv6_pmu_device_probe,
445 };
446
447 builtin_platform_driver(armv6_pmu_driver);
448 #endif /* CONFIG_CPU_V6 || CONFIG_CPU_V6K */
449