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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Perf support for the Statistical Profiling Extension, introduced as
4 * part of ARMv8.2.
5 *
6 * Copyright (C) 2016 ARM Limited
7 *
8 * Author: Will Deacon <will.deacon@arm.com>
9 */
10
11#define PMUNAME "arm_spe"
12#define DRVNAME PMUNAME "_pmu"
13#define pr_fmt(fmt) DRVNAME ": " fmt
14
15#include <linux/bitfield.h>
16#include <linux/bitops.h>
17#include <linux/bug.h>
18#include <linux/capability.h>
19#include <linux/cpuhotplug.h>
20#include <linux/cpumask.h>
21#include <linux/device.h>
22#include <linux/errno.h>
23#include <linux/interrupt.h>
24#include <linux/irq.h>
25#include <linux/kernel.h>
26#include <linux/list.h>
27#include <linux/module.h>
28#include <linux/of.h>
29#include <linux/perf_event.h>
30#include <linux/perf/arm_pmu.h>
31#include <linux/platform_device.h>
32#include <linux/printk.h>
33#include <linux/slab.h>
34#include <linux/smp.h>
35#include <linux/vmalloc.h>
36
37#include <asm/barrier.h>
38#include <asm/cpufeature.h>
39#include <asm/mmu.h>
40#include <asm/sysreg.h>
41
42/*
43 * Cache if the event is allowed to trace Context information.
44 * This allows us to perform the check, i.e, perf_allow_kernel(),
45 * in the context of the event owner, once, during the event_init().
46 */
47#define SPE_PMU_HW_FLAGS_CX 0x00001
48
49static_assert((PERF_EVENT_FLAG_ARCH & SPE_PMU_HW_FLAGS_CX) == SPE_PMU_HW_FLAGS_CX);
50
51static void set_spe_event_has_cx(struct perf_event *event)
52{
53 if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && !perf_allow_kernel(&event->attr))
54 event->hw.flags |= SPE_PMU_HW_FLAGS_CX;
55}
56
57static bool get_spe_event_has_cx(struct perf_event *event)
58{
59 return !!(event->hw.flags & SPE_PMU_HW_FLAGS_CX);
60}
61
62#define ARM_SPE_BUF_PAD_BYTE 0
63
64struct arm_spe_pmu_buf {
65 int nr_pages;
66 bool snapshot;
67 void *base;
68};
69
70struct arm_spe_pmu {
71 struct pmu pmu;
72 struct platform_device *pdev;
73 cpumask_t supported_cpus;
74 struct hlist_node hotplug_node;
75
76 int irq; /* PPI */
77 u16 pmsver;
78 u16 min_period;
79 u16 counter_sz;
80
81#define SPE_PMU_FEAT_FILT_EVT (1UL << 0)
82#define SPE_PMU_FEAT_FILT_TYP (1UL << 1)
83#define SPE_PMU_FEAT_FILT_LAT (1UL << 2)
84#define SPE_PMU_FEAT_ARCH_INST (1UL << 3)
85#define SPE_PMU_FEAT_LDS (1UL << 4)
86#define SPE_PMU_FEAT_ERND (1UL << 5)
87#define SPE_PMU_FEAT_INV_FILT_EVT (1UL << 6)
88#define SPE_PMU_FEAT_DEV_PROBED (1UL << 63)
89 u64 features;
90
91 u16 max_record_sz;
92 u16 align;
93 struct perf_output_handle __percpu *handle;
94};
95
96#define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))
97
98/* Convert a free-running index from perf into an SPE buffer offset */
99#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
100
101/* Keep track of our dynamic hotplug state */
102static enum cpuhp_state arm_spe_pmu_online;
103
104enum arm_spe_pmu_buf_fault_action {
105 SPE_PMU_BUF_FAULT_ACT_SPURIOUS,
106 SPE_PMU_BUF_FAULT_ACT_FATAL,
107 SPE_PMU_BUF_FAULT_ACT_OK,
108};
109
110/* This sysfs gunk was really good fun to write. */
111enum arm_spe_pmu_capabilities {
112 SPE_PMU_CAP_ARCH_INST = 0,
113 SPE_PMU_CAP_ERND,
114 SPE_PMU_CAP_FEAT_MAX,
115 SPE_PMU_CAP_CNT_SZ = SPE_PMU_CAP_FEAT_MAX,
116 SPE_PMU_CAP_MIN_IVAL,
117};
118
119static int arm_spe_pmu_feat_caps[SPE_PMU_CAP_FEAT_MAX] = {
120 [SPE_PMU_CAP_ARCH_INST] = SPE_PMU_FEAT_ARCH_INST,
121 [SPE_PMU_CAP_ERND] = SPE_PMU_FEAT_ERND,
122};
123
124static u32 arm_spe_pmu_cap_get(struct arm_spe_pmu *spe_pmu, int cap)
125{
126 if (cap < SPE_PMU_CAP_FEAT_MAX)
127 return !!(spe_pmu->features & arm_spe_pmu_feat_caps[cap]);
128
129 switch (cap) {
130 case SPE_PMU_CAP_CNT_SZ:
131 return spe_pmu->counter_sz;
132 case SPE_PMU_CAP_MIN_IVAL:
133 return spe_pmu->min_period;
134 default:
135 WARN(1, "unknown cap %d\n", cap);
136 }
137
138 return 0;
139}
140
141static ssize_t arm_spe_pmu_cap_show(struct device *dev,
142 struct device_attribute *attr,
143 char *buf)
144{
145 struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
146 struct dev_ext_attribute *ea =
147 container_of(attr, struct dev_ext_attribute, attr);
148 int cap = (long)ea->var;
149
150 return sysfs_emit(buf, "%u\n", arm_spe_pmu_cap_get(spe_pmu, cap));
151}
152
153#define SPE_EXT_ATTR_ENTRY(_name, _func, _var) \
154 &((struct dev_ext_attribute[]) { \
155 { __ATTR(_name, S_IRUGO, _func, NULL), (void *)_var } \
156 })[0].attr.attr
157
158#define SPE_CAP_EXT_ATTR_ENTRY(_name, _var) \
159 SPE_EXT_ATTR_ENTRY(_name, arm_spe_pmu_cap_show, _var)
160
161static struct attribute *arm_spe_pmu_cap_attr[] = {
162 SPE_CAP_EXT_ATTR_ENTRY(arch_inst, SPE_PMU_CAP_ARCH_INST),
163 SPE_CAP_EXT_ATTR_ENTRY(ernd, SPE_PMU_CAP_ERND),
164 SPE_CAP_EXT_ATTR_ENTRY(count_size, SPE_PMU_CAP_CNT_SZ),
165 SPE_CAP_EXT_ATTR_ENTRY(min_interval, SPE_PMU_CAP_MIN_IVAL),
166 NULL,
167};
168
169static const struct attribute_group arm_spe_pmu_cap_group = {
170 .name = "caps",
171 .attrs = arm_spe_pmu_cap_attr,
172};
173
174/* User ABI */
175#define ATTR_CFG_FLD_ts_enable_CFG config /* PMSCR_EL1.TS */
176#define ATTR_CFG_FLD_ts_enable_LO 0
177#define ATTR_CFG_FLD_ts_enable_HI 0
178#define ATTR_CFG_FLD_pa_enable_CFG config /* PMSCR_EL1.PA */
179#define ATTR_CFG_FLD_pa_enable_LO 1
180#define ATTR_CFG_FLD_pa_enable_HI 1
181#define ATTR_CFG_FLD_pct_enable_CFG config /* PMSCR_EL1.PCT */
182#define ATTR_CFG_FLD_pct_enable_LO 2
183#define ATTR_CFG_FLD_pct_enable_HI 2
184#define ATTR_CFG_FLD_jitter_CFG config /* PMSIRR_EL1.RND */
185#define ATTR_CFG_FLD_jitter_LO 16
186#define ATTR_CFG_FLD_jitter_HI 16
187#define ATTR_CFG_FLD_branch_filter_CFG config /* PMSFCR_EL1.B */
188#define ATTR_CFG_FLD_branch_filter_LO 32
189#define ATTR_CFG_FLD_branch_filter_HI 32
190#define ATTR_CFG_FLD_load_filter_CFG config /* PMSFCR_EL1.LD */
191#define ATTR_CFG_FLD_load_filter_LO 33
192#define ATTR_CFG_FLD_load_filter_HI 33
193#define ATTR_CFG_FLD_store_filter_CFG config /* PMSFCR_EL1.ST */
194#define ATTR_CFG_FLD_store_filter_LO 34
195#define ATTR_CFG_FLD_store_filter_HI 34
196
197#define ATTR_CFG_FLD_event_filter_CFG config1 /* PMSEVFR_EL1 */
198#define ATTR_CFG_FLD_event_filter_LO 0
199#define ATTR_CFG_FLD_event_filter_HI 63
200
201#define ATTR_CFG_FLD_min_latency_CFG config2 /* PMSLATFR_EL1.MINLAT */
202#define ATTR_CFG_FLD_min_latency_LO 0
203#define ATTR_CFG_FLD_min_latency_HI 11
204
205#define ATTR_CFG_FLD_inv_event_filter_CFG config3 /* PMSNEVFR_EL1 */
206#define ATTR_CFG_FLD_inv_event_filter_LO 0
207#define ATTR_CFG_FLD_inv_event_filter_HI 63
208
209GEN_PMU_FORMAT_ATTR(ts_enable);
210GEN_PMU_FORMAT_ATTR(pa_enable);
211GEN_PMU_FORMAT_ATTR(pct_enable);
212GEN_PMU_FORMAT_ATTR(jitter);
213GEN_PMU_FORMAT_ATTR(branch_filter);
214GEN_PMU_FORMAT_ATTR(load_filter);
215GEN_PMU_FORMAT_ATTR(store_filter);
216GEN_PMU_FORMAT_ATTR(event_filter);
217GEN_PMU_FORMAT_ATTR(inv_event_filter);
218GEN_PMU_FORMAT_ATTR(min_latency);
219
220static struct attribute *arm_spe_pmu_formats_attr[] = {
221 &format_attr_ts_enable.attr,
222 &format_attr_pa_enable.attr,
223 &format_attr_pct_enable.attr,
224 &format_attr_jitter.attr,
225 &format_attr_branch_filter.attr,
226 &format_attr_load_filter.attr,
227 &format_attr_store_filter.attr,
228 &format_attr_event_filter.attr,
229 &format_attr_inv_event_filter.attr,
230 &format_attr_min_latency.attr,
231 NULL,
232};
233
234static umode_t arm_spe_pmu_format_attr_is_visible(struct kobject *kobj,
235 struct attribute *attr,
236 int unused)
237 {
238 struct device *dev = kobj_to_dev(kobj);
239 struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
240
241 if (attr == &format_attr_inv_event_filter.attr && !(spe_pmu->features & SPE_PMU_FEAT_INV_FILT_EVT))
242 return 0;
243
244 return attr->mode;
245}
246
247static const struct attribute_group arm_spe_pmu_format_group = {
248 .name = "format",
249 .is_visible = arm_spe_pmu_format_attr_is_visible,
250 .attrs = arm_spe_pmu_formats_attr,
251};
252
253static ssize_t cpumask_show(struct device *dev,
254 struct device_attribute *attr, char *buf)
255{
256 struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev);
257
258 return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
259}
260static DEVICE_ATTR_RO(cpumask);
261
262static struct attribute *arm_spe_pmu_attrs[] = {
263 &dev_attr_cpumask.attr,
264 NULL,
265};
266
267static const struct attribute_group arm_spe_pmu_group = {
268 .attrs = arm_spe_pmu_attrs,
269};
270
271static const struct attribute_group *arm_spe_pmu_attr_groups[] = {
272 &arm_spe_pmu_group,
273 &arm_spe_pmu_cap_group,
274 &arm_spe_pmu_format_group,
275 NULL,
276};
277
278/* Convert between user ABI and register values */
279static u64 arm_spe_event_to_pmscr(struct perf_event *event)
280{
281 struct perf_event_attr *attr = &event->attr;
282 u64 reg = 0;
283
284 reg |= FIELD_PREP(PMSCR_EL1_TS, ATTR_CFG_GET_FLD(attr, ts_enable));
285 reg |= FIELD_PREP(PMSCR_EL1_PA, ATTR_CFG_GET_FLD(attr, pa_enable));
286 reg |= FIELD_PREP(PMSCR_EL1_PCT, ATTR_CFG_GET_FLD(attr, pct_enable));
287
288 if (!attr->exclude_user)
289 reg |= PMSCR_EL1_E0SPE;
290
291 if (!attr->exclude_kernel)
292 reg |= PMSCR_EL1_E1SPE;
293
294 if (get_spe_event_has_cx(event))
295 reg |= PMSCR_EL1_CX;
296
297 return reg;
298}
299
300static void arm_spe_event_sanitise_period(struct perf_event *event)
301{
302 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
303 u64 period = event->hw.sample_period;
304 u64 max_period = PMSIRR_EL1_INTERVAL_MASK;
305
306 if (period < spe_pmu->min_period)
307 period = spe_pmu->min_period;
308 else if (period > max_period)
309 period = max_period;
310 else
311 period &= max_period;
312
313 event->hw.sample_period = period;
314}
315
316static u64 arm_spe_event_to_pmsirr(struct perf_event *event)
317{
318 struct perf_event_attr *attr = &event->attr;
319 u64 reg = 0;
320
321 arm_spe_event_sanitise_period(event);
322
323 reg |= FIELD_PREP(PMSIRR_EL1_RND, ATTR_CFG_GET_FLD(attr, jitter));
324 reg |= event->hw.sample_period;
325
326 return reg;
327}
328
329static u64 arm_spe_event_to_pmsfcr(struct perf_event *event)
330{
331 struct perf_event_attr *attr = &event->attr;
332 u64 reg = 0;
333
334 reg |= FIELD_PREP(PMSFCR_EL1_LD, ATTR_CFG_GET_FLD(attr, load_filter));
335 reg |= FIELD_PREP(PMSFCR_EL1_ST, ATTR_CFG_GET_FLD(attr, store_filter));
336 reg |= FIELD_PREP(PMSFCR_EL1_B, ATTR_CFG_GET_FLD(attr, branch_filter));
337
338 if (reg)
339 reg |= PMSFCR_EL1_FT;
340
341 if (ATTR_CFG_GET_FLD(attr, event_filter))
342 reg |= PMSFCR_EL1_FE;
343
344 if (ATTR_CFG_GET_FLD(attr, inv_event_filter))
345 reg |= PMSFCR_EL1_FnE;
346
347 if (ATTR_CFG_GET_FLD(attr, min_latency))
348 reg |= PMSFCR_EL1_FL;
349
350 return reg;
351}
352
353static u64 arm_spe_event_to_pmsevfr(struct perf_event *event)
354{
355 struct perf_event_attr *attr = &event->attr;
356 return ATTR_CFG_GET_FLD(attr, event_filter);
357}
358
359static u64 arm_spe_event_to_pmsnevfr(struct perf_event *event)
360{
361 struct perf_event_attr *attr = &event->attr;
362 return ATTR_CFG_GET_FLD(attr, inv_event_filter);
363}
364
365static u64 arm_spe_event_to_pmslatfr(struct perf_event *event)
366{
367 struct perf_event_attr *attr = &event->attr;
368 return FIELD_PREP(PMSLATFR_EL1_MINLAT, ATTR_CFG_GET_FLD(attr, min_latency));
369}
370
371static void arm_spe_pmu_pad_buf(struct perf_output_handle *handle, int len)
372{
373 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
374 u64 head = PERF_IDX2OFF(handle->head, buf);
375
376 memset(buf->base + head, ARM_SPE_BUF_PAD_BYTE, len);
377 if (!buf->snapshot)
378 perf_aux_output_skip(handle, len);
379}
380
381static u64 arm_spe_pmu_next_snapshot_off(struct perf_output_handle *handle)
382{
383 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
384 struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
385 u64 head = PERF_IDX2OFF(handle->head, buf);
386 u64 limit = buf->nr_pages * PAGE_SIZE;
387
388 /*
389 * The trace format isn't parseable in reverse, so clamp
390 * the limit to half of the buffer size in snapshot mode
391 * so that the worst case is half a buffer of records, as
392 * opposed to a single record.
393 */
394 if (head < limit >> 1)
395 limit >>= 1;
396
397 /*
398 * If we're within max_record_sz of the limit, we must
399 * pad, move the head index and recompute the limit.
400 */
401 if (limit - head < spe_pmu->max_record_sz) {
402 arm_spe_pmu_pad_buf(handle, limit - head);
403 handle->head = PERF_IDX2OFF(limit, buf);
404 limit = ((buf->nr_pages * PAGE_SIZE) >> 1) + handle->head;
405 }
406
407 return limit;
408}
409
410static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle)
411{
412 struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
413 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
414 const u64 bufsize = buf->nr_pages * PAGE_SIZE;
415 u64 limit = bufsize;
416 u64 head, tail, wakeup;
417
418 /*
419 * The head can be misaligned for two reasons:
420 *
421 * 1. The hardware left PMBPTR pointing to the first byte after
422 * a record when generating a buffer management event.
423 *
424 * 2. We used perf_aux_output_skip to consume handle->size bytes
425 * and CIRC_SPACE was used to compute the size, which always
426 * leaves one entry free.
427 *
428 * Deal with this by padding to the next alignment boundary and
429 * moving the head index. If we run out of buffer space, we'll
430 * reduce handle->size to zero and end up reporting truncation.
431 */
432 head = PERF_IDX2OFF(handle->head, buf);
433 if (!IS_ALIGNED(head, spe_pmu->align)) {
434 unsigned long delta = roundup(head, spe_pmu->align) - head;
435
436 delta = min(delta, handle->size);
437 arm_spe_pmu_pad_buf(handle, delta);
438 head = PERF_IDX2OFF(handle->head, buf);
439 }
440
441 /* If we've run out of free space, then nothing more to do */
442 if (!handle->size)
443 goto no_space;
444
445 /* Compute the tail and wakeup indices now that we've aligned head */
446 tail = PERF_IDX2OFF(handle->head + handle->size, buf);
447 wakeup = PERF_IDX2OFF(handle->wakeup, buf);
448
449 /*
450 * Avoid clobbering unconsumed data. We know we have space, so
451 * if we see head == tail we know that the buffer is empty. If
452 * head > tail, then there's nothing to clobber prior to
453 * wrapping.
454 */
455 if (head < tail)
456 limit = round_down(tail, PAGE_SIZE);
457
458 /*
459 * Wakeup may be arbitrarily far into the future. If it's not in
460 * the current generation, either we'll wrap before hitting it,
461 * or it's in the past and has been handled already.
462 *
463 * If there's a wakeup before we wrap, arrange to be woken up by
464 * the page boundary following it. Keep the tail boundary if
465 * that's lower.
466 */
467 if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
468 limit = min(limit, round_up(wakeup, PAGE_SIZE));
469
470 if (limit > head)
471 return limit;
472
473 arm_spe_pmu_pad_buf(handle, handle->size);
474no_space:
475 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
476 perf_aux_output_end(handle, 0);
477 return 0;
478}
479
480static u64 arm_spe_pmu_next_off(struct perf_output_handle *handle)
481{
482 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
483 struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
484 u64 limit = __arm_spe_pmu_next_off(handle);
485 u64 head = PERF_IDX2OFF(handle->head, buf);
486
487 /*
488 * If the head has come too close to the end of the buffer,
489 * then pad to the end and recompute the limit.
490 */
491 if (limit && (limit - head < spe_pmu->max_record_sz)) {
492 arm_spe_pmu_pad_buf(handle, limit - head);
493 limit = __arm_spe_pmu_next_off(handle);
494 }
495
496 return limit;
497}
498
499static void arm_spe_perf_aux_output_begin(struct perf_output_handle *handle,
500 struct perf_event *event)
501{
502 u64 base, limit;
503 struct arm_spe_pmu_buf *buf;
504
505 /* Start a new aux session */
506 buf = perf_aux_output_begin(handle, event);
507 if (!buf) {
508 event->hw.state |= PERF_HES_STOPPED;
509 /*
510 * We still need to clear the limit pointer, since the
511 * profiler might only be disabled by virtue of a fault.
512 */
513 limit = 0;
514 goto out_write_limit;
515 }
516
517 limit = buf->snapshot ? arm_spe_pmu_next_snapshot_off(handle)
518 : arm_spe_pmu_next_off(handle);
519 if (limit)
520 limit |= PMBLIMITR_EL1_E;
521
522 limit += (u64)buf->base;
523 base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf);
524 write_sysreg_s(base, SYS_PMBPTR_EL1);
525
526out_write_limit:
527 write_sysreg_s(limit, SYS_PMBLIMITR_EL1);
528}
529
530static void arm_spe_perf_aux_output_end(struct perf_output_handle *handle)
531{
532 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
533 u64 offset, size;
534
535 offset = read_sysreg_s(SYS_PMBPTR_EL1) - (u64)buf->base;
536 size = offset - PERF_IDX2OFF(handle->head, buf);
537
538 if (buf->snapshot)
539 handle->head = offset;
540
541 perf_aux_output_end(handle, size);
542}
543
544static void arm_spe_pmu_disable_and_drain_local(void)
545{
546 /* Disable profiling at EL0 and EL1 */
547 write_sysreg_s(0, SYS_PMSCR_EL1);
548 isb();
549
550 /* Drain any buffered data */
551 psb_csync();
552 dsb(nsh);
553
554 /* Disable the profiling buffer */
555 write_sysreg_s(0, SYS_PMBLIMITR_EL1);
556 isb();
557}
558
559/* IRQ handling */
560static enum arm_spe_pmu_buf_fault_action
561arm_spe_pmu_buf_get_fault_act(struct perf_output_handle *handle)
562{
563 const char *err_str;
564 u64 pmbsr;
565 enum arm_spe_pmu_buf_fault_action ret;
566
567 /*
568 * Ensure new profiling data is visible to the CPU and any external
569 * aborts have been resolved.
570 */
571 psb_csync();
572 dsb(nsh);
573
574 /* Ensure hardware updates to PMBPTR_EL1 are visible */
575 isb();
576
577 /* Service required? */
578 pmbsr = read_sysreg_s(SYS_PMBSR_EL1);
579 if (!FIELD_GET(PMBSR_EL1_S, pmbsr))
580 return SPE_PMU_BUF_FAULT_ACT_SPURIOUS;
581
582 /*
583 * If we've lost data, disable profiling and also set the PARTIAL
584 * flag to indicate that the last record is corrupted.
585 */
586 if (FIELD_GET(PMBSR_EL1_DL, pmbsr))
587 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED |
588 PERF_AUX_FLAG_PARTIAL);
589
590 /* Report collisions to userspace so that it can up the period */
591 if (FIELD_GET(PMBSR_EL1_COLL, pmbsr))
592 perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
593
594 /* We only expect buffer management events */
595 switch (FIELD_GET(PMBSR_EL1_EC, pmbsr)) {
596 case PMBSR_EL1_EC_BUF:
597 /* Handled below */
598 break;
599 case PMBSR_EL1_EC_FAULT_S1:
600 case PMBSR_EL1_EC_FAULT_S2:
601 err_str = "Unexpected buffer fault";
602 goto out_err;
603 default:
604 err_str = "Unknown error code";
605 goto out_err;
606 }
607
608 /* Buffer management event */
609 switch (FIELD_GET(PMBSR_EL1_BUF_BSC_MASK, pmbsr)) {
610 case PMBSR_EL1_BUF_BSC_FULL:
611 ret = SPE_PMU_BUF_FAULT_ACT_OK;
612 goto out_stop;
613 default:
614 err_str = "Unknown buffer status code";
615 }
616
617out_err:
618 pr_err_ratelimited("%s on CPU %d [PMBSR=0x%016llx, PMBPTR=0x%016llx, PMBLIMITR=0x%016llx]\n",
619 err_str, smp_processor_id(), pmbsr,
620 read_sysreg_s(SYS_PMBPTR_EL1),
621 read_sysreg_s(SYS_PMBLIMITR_EL1));
622 ret = SPE_PMU_BUF_FAULT_ACT_FATAL;
623
624out_stop:
625 arm_spe_perf_aux_output_end(handle);
626 return ret;
627}
628
629static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev)
630{
631 struct perf_output_handle *handle = dev;
632 struct perf_event *event = handle->event;
633 enum arm_spe_pmu_buf_fault_action act;
634
635 if (!perf_get_aux(handle))
636 return IRQ_NONE;
637
638 act = arm_spe_pmu_buf_get_fault_act(handle);
639 if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
640 return IRQ_NONE;
641
642 /*
643 * Ensure perf callbacks have completed, which may disable the
644 * profiling buffer in response to a TRUNCATION flag.
645 */
646 irq_work_run();
647
648 switch (act) {
649 case SPE_PMU_BUF_FAULT_ACT_FATAL:
650 /*
651 * If a fatal exception occurred then leaving the profiling
652 * buffer enabled is a recipe waiting to happen. Since
653 * fatal faults don't always imply truncation, make sure
654 * that the profiling buffer is disabled explicitly before
655 * clearing the syndrome register.
656 */
657 arm_spe_pmu_disable_and_drain_local();
658 break;
659 case SPE_PMU_BUF_FAULT_ACT_OK:
660 /*
661 * We handled the fault (the buffer was full), so resume
662 * profiling as long as we didn't detect truncation.
663 * PMBPTR might be misaligned, but we'll burn that bridge
664 * when we get to it.
665 */
666 if (!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)) {
667 arm_spe_perf_aux_output_begin(handle, event);
668 isb();
669 }
670 break;
671 case SPE_PMU_BUF_FAULT_ACT_SPURIOUS:
672 /* We've seen you before, but GCC has the memory of a sieve. */
673 break;
674 }
675
676 /* The buffer pointers are now sane, so resume profiling. */
677 write_sysreg_s(0, SYS_PMBSR_EL1);
678 return IRQ_HANDLED;
679}
680
681static u64 arm_spe_pmsevfr_res0(u16 pmsver)
682{
683 switch (pmsver) {
684 case ID_AA64DFR0_EL1_PMSVer_IMP:
685 return PMSEVFR_EL1_RES0_IMP;
686 case ID_AA64DFR0_EL1_PMSVer_V1P1:
687 return PMSEVFR_EL1_RES0_V1P1;
688 case ID_AA64DFR0_EL1_PMSVer_V1P2:
689 /* Return the highest version we support in default */
690 default:
691 return PMSEVFR_EL1_RES0_V1P2;
692 }
693}
694
695/* Perf callbacks */
696static int arm_spe_pmu_event_init(struct perf_event *event)
697{
698 u64 reg;
699 struct perf_event_attr *attr = &event->attr;
700 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
701
702 /* This is, of course, deeply driver-specific */
703 if (attr->type != event->pmu->type)
704 return -ENOENT;
705
706 if (event->cpu >= 0 &&
707 !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus))
708 return -ENOENT;
709
710 if (arm_spe_event_to_pmsevfr(event) & arm_spe_pmsevfr_res0(spe_pmu->pmsver))
711 return -EOPNOTSUPP;
712
713 if (arm_spe_event_to_pmsnevfr(event) & arm_spe_pmsevfr_res0(spe_pmu->pmsver))
714 return -EOPNOTSUPP;
715
716 if (attr->exclude_idle)
717 return -EOPNOTSUPP;
718
719 /*
720 * Feedback-directed frequency throttling doesn't work when we
721 * have a buffer of samples. We'd need to manually count the
722 * samples in the buffer when it fills up and adjust the event
723 * count to reflect that. Instead, just force the user to specify
724 * a sample period.
725 */
726 if (attr->freq)
727 return -EINVAL;
728
729 reg = arm_spe_event_to_pmsfcr(event);
730 if ((FIELD_GET(PMSFCR_EL1_FE, reg)) &&
731 !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT))
732 return -EOPNOTSUPP;
733
734 if ((FIELD_GET(PMSFCR_EL1_FnE, reg)) &&
735 !(spe_pmu->features & SPE_PMU_FEAT_INV_FILT_EVT))
736 return -EOPNOTSUPP;
737
738 if ((FIELD_GET(PMSFCR_EL1_FT, reg)) &&
739 !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP))
740 return -EOPNOTSUPP;
741
742 if ((FIELD_GET(PMSFCR_EL1_FL, reg)) &&
743 !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
744 return -EOPNOTSUPP;
745
746 set_spe_event_has_cx(event);
747 reg = arm_spe_event_to_pmscr(event);
748 if (reg & (PMSCR_EL1_PA | PMSCR_EL1_PCT))
749 return perf_allow_kernel(&event->attr);
750
751 return 0;
752}
753
754static void arm_spe_pmu_start(struct perf_event *event, int flags)
755{
756 u64 reg;
757 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
758 struct hw_perf_event *hwc = &event->hw;
759 struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
760
761 hwc->state = 0;
762 arm_spe_perf_aux_output_begin(handle, event);
763 if (hwc->state)
764 return;
765
766 reg = arm_spe_event_to_pmsfcr(event);
767 write_sysreg_s(reg, SYS_PMSFCR_EL1);
768
769 reg = arm_spe_event_to_pmsevfr(event);
770 write_sysreg_s(reg, SYS_PMSEVFR_EL1);
771
772 if (spe_pmu->features & SPE_PMU_FEAT_INV_FILT_EVT) {
773 reg = arm_spe_event_to_pmsnevfr(event);
774 write_sysreg_s(reg, SYS_PMSNEVFR_EL1);
775 }
776
777 reg = arm_spe_event_to_pmslatfr(event);
778 write_sysreg_s(reg, SYS_PMSLATFR_EL1);
779
780 if (flags & PERF_EF_RELOAD) {
781 reg = arm_spe_event_to_pmsirr(event);
782 write_sysreg_s(reg, SYS_PMSIRR_EL1);
783 isb();
784 reg = local64_read(&hwc->period_left);
785 write_sysreg_s(reg, SYS_PMSICR_EL1);
786 }
787
788 reg = arm_spe_event_to_pmscr(event);
789 isb();
790 write_sysreg_s(reg, SYS_PMSCR_EL1);
791}
792
793static void arm_spe_pmu_stop(struct perf_event *event, int flags)
794{
795 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
796 struct hw_perf_event *hwc = &event->hw;
797 struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
798
799 /* If we're already stopped, then nothing to do */
800 if (hwc->state & PERF_HES_STOPPED)
801 return;
802
803 /* Stop all trace generation */
804 arm_spe_pmu_disable_and_drain_local();
805
806 if (flags & PERF_EF_UPDATE) {
807 /*
808 * If there's a fault pending then ensure we contain it
809 * to this buffer, since we might be on the context-switch
810 * path.
811 */
812 if (perf_get_aux(handle)) {
813 enum arm_spe_pmu_buf_fault_action act;
814
815 act = arm_spe_pmu_buf_get_fault_act(handle);
816 if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
817 arm_spe_perf_aux_output_end(handle);
818 else
819 write_sysreg_s(0, SYS_PMBSR_EL1);
820 }
821
822 /*
823 * This may also contain ECOUNT, but nobody else should
824 * be looking at period_left, since we forbid frequency
825 * based sampling.
826 */
827 local64_set(&hwc->period_left, read_sysreg_s(SYS_PMSICR_EL1));
828 hwc->state |= PERF_HES_UPTODATE;
829 }
830
831 hwc->state |= PERF_HES_STOPPED;
832}
833
834static int arm_spe_pmu_add(struct perf_event *event, int flags)
835{
836 int ret = 0;
837 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
838 struct hw_perf_event *hwc = &event->hw;
839 int cpu = event->cpu == -1 ? smp_processor_id() : event->cpu;
840
841 if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
842 return -ENOENT;
843
844 hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
845
846 if (flags & PERF_EF_START) {
847 arm_spe_pmu_start(event, PERF_EF_RELOAD);
848 if (hwc->state & PERF_HES_STOPPED)
849 ret = -EINVAL;
850 }
851
852 return ret;
853}
854
855static void arm_spe_pmu_del(struct perf_event *event, int flags)
856{
857 arm_spe_pmu_stop(event, PERF_EF_UPDATE);
858}
859
860static void arm_spe_pmu_read(struct perf_event *event)
861{
862}
863
864static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages,
865 int nr_pages, bool snapshot)
866{
867 int i, cpu = event->cpu;
868 struct page **pglist;
869 struct arm_spe_pmu_buf *buf;
870
871 /* We need at least two pages for this to work. */
872 if (nr_pages < 2)
873 return NULL;
874
875 /*
876 * We require an even number of pages for snapshot mode, so that
877 * we can effectively treat the buffer as consisting of two equal
878 * parts and give userspace a fighting chance of getting some
879 * useful data out of it.
880 */
881 if (snapshot && (nr_pages & 1))
882 return NULL;
883
884 if (cpu == -1)
885 cpu = raw_smp_processor_id();
886
887 buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, cpu_to_node(cpu));
888 if (!buf)
889 return NULL;
890
891 pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
892 if (!pglist)
893 goto out_free_buf;
894
895 for (i = 0; i < nr_pages; ++i)
896 pglist[i] = virt_to_page(pages[i]);
897
898 buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
899 if (!buf->base)
900 goto out_free_pglist;
901
902 buf->nr_pages = nr_pages;
903 buf->snapshot = snapshot;
904
905 kfree(pglist);
906 return buf;
907
908out_free_pglist:
909 kfree(pglist);
910out_free_buf:
911 kfree(buf);
912 return NULL;
913}
914
915static void arm_spe_pmu_free_aux(void *aux)
916{
917 struct arm_spe_pmu_buf *buf = aux;
918
919 vunmap(buf->base);
920 kfree(buf);
921}
922
923/* Initialisation and teardown functions */
924static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
925{
926 static atomic_t pmu_idx = ATOMIC_INIT(-1);
927
928 int idx;
929 char *name;
930 struct device *dev = &spe_pmu->pdev->dev;
931
932 spe_pmu->pmu = (struct pmu) {
933 .module = THIS_MODULE,
934 .parent = &spe_pmu->pdev->dev,
935 .capabilities = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
936 .attr_groups = arm_spe_pmu_attr_groups,
937 /*
938 * We hitch a ride on the software context here, so that
939 * we can support per-task profiling (which is not possible
940 * with the invalid context as it doesn't get sched callbacks).
941 * This requires that userspace either uses a dummy event for
942 * perf_event_open, since the aux buffer is not setup until
943 * a subsequent mmap, or creates the profiling event in a
944 * disabled state and explicitly PERF_EVENT_IOC_ENABLEs it
945 * once the buffer has been created.
946 */
947 .task_ctx_nr = perf_sw_context,
948 .event_init = arm_spe_pmu_event_init,
949 .add = arm_spe_pmu_add,
950 .del = arm_spe_pmu_del,
951 .start = arm_spe_pmu_start,
952 .stop = arm_spe_pmu_stop,
953 .read = arm_spe_pmu_read,
954 .setup_aux = arm_spe_pmu_setup_aux,
955 .free_aux = arm_spe_pmu_free_aux,
956 };
957
958 idx = atomic_inc_return(&pmu_idx);
959 name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx);
960 if (!name) {
961 dev_err(dev, "failed to allocate name for pmu %d\n", idx);
962 return -ENOMEM;
963 }
964
965 return perf_pmu_register(&spe_pmu->pmu, name, -1);
966}
967
968static void arm_spe_pmu_perf_destroy(struct arm_spe_pmu *spe_pmu)
969{
970 perf_pmu_unregister(&spe_pmu->pmu);
971}
972
973static void __arm_spe_pmu_dev_probe(void *info)
974{
975 int fld;
976 u64 reg;
977 struct arm_spe_pmu *spe_pmu = info;
978 struct device *dev = &spe_pmu->pdev->dev;
979
980 fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64DFR0_EL1),
981 ID_AA64DFR0_EL1_PMSVer_SHIFT);
982 if (!fld) {
983 dev_err(dev,
984 "unsupported ID_AA64DFR0_EL1.PMSVer [%d] on CPU %d\n",
985 fld, smp_processor_id());
986 return;
987 }
988 spe_pmu->pmsver = (u16)fld;
989
990 /* Read PMBIDR first to determine whether or not we have access */
991 reg = read_sysreg_s(SYS_PMBIDR_EL1);
992 if (FIELD_GET(PMBIDR_EL1_P, reg)) {
993 dev_err(dev,
994 "profiling buffer owned by higher exception level\n");
995 return;
996 }
997
998 /* Minimum alignment. If it's out-of-range, then fail the probe */
999 fld = FIELD_GET(PMBIDR_EL1_ALIGN, reg);
1000 spe_pmu->align = 1 << fld;
1001 if (spe_pmu->align > SZ_2K) {
1002 dev_err(dev, "unsupported PMBIDR.Align [%d] on CPU %d\n",
1003 fld, smp_processor_id());
1004 return;
1005 }
1006
1007 /* It's now safe to read PMSIDR and figure out what we've got */
1008 reg = read_sysreg_s(SYS_PMSIDR_EL1);
1009 if (FIELD_GET(PMSIDR_EL1_FE, reg))
1010 spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT;
1011
1012 if (FIELD_GET(PMSIDR_EL1_FnE, reg))
1013 spe_pmu->features |= SPE_PMU_FEAT_INV_FILT_EVT;
1014
1015 if (FIELD_GET(PMSIDR_EL1_FT, reg))
1016 spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP;
1017
1018 if (FIELD_GET(PMSIDR_EL1_FL, reg))
1019 spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT;
1020
1021 if (FIELD_GET(PMSIDR_EL1_ARCHINST, reg))
1022 spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST;
1023
1024 if (FIELD_GET(PMSIDR_EL1_LDS, reg))
1025 spe_pmu->features |= SPE_PMU_FEAT_LDS;
1026
1027 if (FIELD_GET(PMSIDR_EL1_ERND, reg))
1028 spe_pmu->features |= SPE_PMU_FEAT_ERND;
1029
1030 /* This field has a spaced out encoding, so just use a look-up */
1031 fld = FIELD_GET(PMSIDR_EL1_INTERVAL, reg);
1032 switch (fld) {
1033 case PMSIDR_EL1_INTERVAL_256:
1034 spe_pmu->min_period = 256;
1035 break;
1036 case PMSIDR_EL1_INTERVAL_512:
1037 spe_pmu->min_period = 512;
1038 break;
1039 case PMSIDR_EL1_INTERVAL_768:
1040 spe_pmu->min_period = 768;
1041 break;
1042 case PMSIDR_EL1_INTERVAL_1024:
1043 spe_pmu->min_period = 1024;
1044 break;
1045 case PMSIDR_EL1_INTERVAL_1536:
1046 spe_pmu->min_period = 1536;
1047 break;
1048 case PMSIDR_EL1_INTERVAL_2048:
1049 spe_pmu->min_period = 2048;
1050 break;
1051 case PMSIDR_EL1_INTERVAL_3072:
1052 spe_pmu->min_period = 3072;
1053 break;
1054 default:
1055 dev_warn(dev, "unknown PMSIDR_EL1.Interval [%d]; assuming 8\n",
1056 fld);
1057 fallthrough;
1058 case PMSIDR_EL1_INTERVAL_4096:
1059 spe_pmu->min_period = 4096;
1060 }
1061
1062 /* Maximum record size. If it's out-of-range, then fail the probe */
1063 fld = FIELD_GET(PMSIDR_EL1_MAXSIZE, reg);
1064 spe_pmu->max_record_sz = 1 << fld;
1065 if (spe_pmu->max_record_sz > SZ_2K || spe_pmu->max_record_sz < 16) {
1066 dev_err(dev, "unsupported PMSIDR_EL1.MaxSize [%d] on CPU %d\n",
1067 fld, smp_processor_id());
1068 return;
1069 }
1070
1071 fld = FIELD_GET(PMSIDR_EL1_COUNTSIZE, reg);
1072 switch (fld) {
1073 default:
1074 dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n",
1075 fld);
1076 fallthrough;
1077 case PMSIDR_EL1_COUNTSIZE_12_BIT_SAT:
1078 spe_pmu->counter_sz = 12;
1079 break;
1080 case PMSIDR_EL1_COUNTSIZE_16_BIT_SAT:
1081 spe_pmu->counter_sz = 16;
1082 }
1083
1084 dev_info(dev,
1085 "probed SPEv1.%d for CPUs %*pbl [max_record_sz %u, align %u, features 0x%llx]\n",
1086 spe_pmu->pmsver - 1, cpumask_pr_args(&spe_pmu->supported_cpus),
1087 spe_pmu->max_record_sz, spe_pmu->align, spe_pmu->features);
1088
1089 spe_pmu->features |= SPE_PMU_FEAT_DEV_PROBED;
1090}
1091
1092static void __arm_spe_pmu_reset_local(void)
1093{
1094 /*
1095 * This is probably overkill, as we have no idea where we're
1096 * draining any buffered data to...
1097 */
1098 arm_spe_pmu_disable_and_drain_local();
1099
1100 /* Reset the buffer base pointer */
1101 write_sysreg_s(0, SYS_PMBPTR_EL1);
1102 isb();
1103
1104 /* Clear any pending management interrupts */
1105 write_sysreg_s(0, SYS_PMBSR_EL1);
1106 isb();
1107}
1108
1109static void __arm_spe_pmu_setup_one(void *info)
1110{
1111 struct arm_spe_pmu *spe_pmu = info;
1112
1113 __arm_spe_pmu_reset_local();
1114 enable_percpu_irq(spe_pmu->irq, IRQ_TYPE_NONE);
1115}
1116
1117static void __arm_spe_pmu_stop_one(void *info)
1118{
1119 struct arm_spe_pmu *spe_pmu = info;
1120
1121 disable_percpu_irq(spe_pmu->irq);
1122 __arm_spe_pmu_reset_local();
1123}
1124
1125static int arm_spe_pmu_cpu_startup(unsigned int cpu, struct hlist_node *node)
1126{
1127 struct arm_spe_pmu *spe_pmu;
1128
1129 spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1130 if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1131 return 0;
1132
1133 __arm_spe_pmu_setup_one(spe_pmu);
1134 return 0;
1135}
1136
1137static int arm_spe_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
1138{
1139 struct arm_spe_pmu *spe_pmu;
1140
1141 spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1142 if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1143 return 0;
1144
1145 __arm_spe_pmu_stop_one(spe_pmu);
1146 return 0;
1147}
1148
1149static int arm_spe_pmu_dev_init(struct arm_spe_pmu *spe_pmu)
1150{
1151 int ret;
1152 cpumask_t *mask = &spe_pmu->supported_cpus;
1153
1154 /* Make sure we probe the hardware on a relevant CPU */
1155 ret = smp_call_function_any(mask, __arm_spe_pmu_dev_probe, spe_pmu, 1);
1156 if (ret || !(spe_pmu->features & SPE_PMU_FEAT_DEV_PROBED))
1157 return -ENXIO;
1158
1159 /* Request our PPIs (note that the IRQ is still disabled) */
1160 ret = request_percpu_irq(spe_pmu->irq, arm_spe_pmu_irq_handler, DRVNAME,
1161 spe_pmu->handle);
1162 if (ret)
1163 return ret;
1164
1165 /*
1166 * Register our hotplug notifier now so we don't miss any events.
1167 * This will enable the IRQ for any supported CPUs that are already
1168 * up.
1169 */
1170 ret = cpuhp_state_add_instance(arm_spe_pmu_online,
1171 &spe_pmu->hotplug_node);
1172 if (ret)
1173 free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1174
1175 return ret;
1176}
1177
1178static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu)
1179{
1180 cpuhp_state_remove_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node);
1181 free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1182}
1183
1184/* Driver and device probing */
1185static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu)
1186{
1187 struct platform_device *pdev = spe_pmu->pdev;
1188 int irq = platform_get_irq(pdev, 0);
1189
1190 if (irq < 0)
1191 return -ENXIO;
1192
1193 if (!irq_is_percpu(irq)) {
1194 dev_err(&pdev->dev, "expected PPI but got SPI (%d)\n", irq);
1195 return -EINVAL;
1196 }
1197
1198 if (irq_get_percpu_devid_partition(irq, &spe_pmu->supported_cpus)) {
1199 dev_err(&pdev->dev, "failed to get PPI partition (%d)\n", irq);
1200 return -EINVAL;
1201 }
1202
1203 spe_pmu->irq = irq;
1204 return 0;
1205}
1206
1207static const struct of_device_id arm_spe_pmu_of_match[] = {
1208 { .compatible = "arm,statistical-profiling-extension-v1", .data = (void *)1 },
1209 { /* Sentinel */ },
1210};
1211MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match);
1212
1213static const struct platform_device_id arm_spe_match[] = {
1214 { ARMV8_SPE_PDEV_NAME, 0},
1215 { }
1216};
1217MODULE_DEVICE_TABLE(platform, arm_spe_match);
1218
1219static int arm_spe_pmu_device_probe(struct platform_device *pdev)
1220{
1221 int ret;
1222 struct arm_spe_pmu *spe_pmu;
1223 struct device *dev = &pdev->dev;
1224
1225 /*
1226 * If kernelspace is unmapped when running at EL0, then the SPE
1227 * buffer will fault and prematurely terminate the AUX session.
1228 */
1229 if (arm64_kernel_unmapped_at_el0()) {
1230 dev_warn_once(dev, "profiling buffer inaccessible. Try passing \"kpti=off\" on the kernel command line\n");
1231 return -EPERM;
1232 }
1233
1234 spe_pmu = devm_kzalloc(dev, sizeof(*spe_pmu), GFP_KERNEL);
1235 if (!spe_pmu)
1236 return -ENOMEM;
1237
1238 spe_pmu->handle = alloc_percpu(typeof(*spe_pmu->handle));
1239 if (!spe_pmu->handle)
1240 return -ENOMEM;
1241
1242 spe_pmu->pdev = pdev;
1243 platform_set_drvdata(pdev, spe_pmu);
1244
1245 ret = arm_spe_pmu_irq_probe(spe_pmu);
1246 if (ret)
1247 goto out_free_handle;
1248
1249 ret = arm_spe_pmu_dev_init(spe_pmu);
1250 if (ret)
1251 goto out_free_handle;
1252
1253 ret = arm_spe_pmu_perf_init(spe_pmu);
1254 if (ret)
1255 goto out_teardown_dev;
1256
1257 return 0;
1258
1259out_teardown_dev:
1260 arm_spe_pmu_dev_teardown(spe_pmu);
1261out_free_handle:
1262 free_percpu(spe_pmu->handle);
1263 return ret;
1264}
1265
1266static void arm_spe_pmu_device_remove(struct platform_device *pdev)
1267{
1268 struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
1269
1270 arm_spe_pmu_perf_destroy(spe_pmu);
1271 arm_spe_pmu_dev_teardown(spe_pmu);
1272 free_percpu(spe_pmu->handle);
1273}
1274
1275static struct platform_driver arm_spe_pmu_driver = {
1276 .id_table = arm_spe_match,
1277 .driver = {
1278 .name = DRVNAME,
1279 .of_match_table = of_match_ptr(arm_spe_pmu_of_match),
1280 .suppress_bind_attrs = true,
1281 },
1282 .probe = arm_spe_pmu_device_probe,
1283 .remove = arm_spe_pmu_device_remove,
1284};
1285
1286static int __init arm_spe_pmu_init(void)
1287{
1288 int ret;
1289
1290 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
1291 arm_spe_pmu_cpu_startup,
1292 arm_spe_pmu_cpu_teardown);
1293 if (ret < 0)
1294 return ret;
1295 arm_spe_pmu_online = ret;
1296
1297 ret = platform_driver_register(&arm_spe_pmu_driver);
1298 if (ret)
1299 cpuhp_remove_multi_state(arm_spe_pmu_online);
1300
1301 return ret;
1302}
1303
1304static void __exit arm_spe_pmu_exit(void)
1305{
1306 platform_driver_unregister(&arm_spe_pmu_driver);
1307 cpuhp_remove_multi_state(arm_spe_pmu_online);
1308}
1309
1310module_init(arm_spe_pmu_init);
1311module_exit(arm_spe_pmu_exit);
1312
1313MODULE_DESCRIPTION("Perf driver for the ARMv8.2 Statistical Profiling Extension");
1314MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
1315MODULE_LICENSE("GPL v2");
1/*
2 * Perf support for the Statistical Profiling Extension, introduced as
3 * part of ARMv8.2.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
16 *
17 * Copyright (C) 2016 ARM Limited
18 *
19 * Author: Will Deacon <will.deacon@arm.com>
20 */
21
22#define PMUNAME "arm_spe"
23#define DRVNAME PMUNAME "_pmu"
24#define pr_fmt(fmt) DRVNAME ": " fmt
25
26#include <linux/bitops.h>
27#include <linux/bug.h>
28#include <linux/capability.h>
29#include <linux/cpuhotplug.h>
30#include <linux/cpumask.h>
31#include <linux/device.h>
32#include <linux/errno.h>
33#include <linux/interrupt.h>
34#include <linux/irq.h>
35#include <linux/kernel.h>
36#include <linux/list.h>
37#include <linux/module.h>
38#include <linux/of_address.h>
39#include <linux/of_device.h>
40#include <linux/perf_event.h>
41#include <linux/platform_device.h>
42#include <linux/printk.h>
43#include <linux/slab.h>
44#include <linux/smp.h>
45#include <linux/vmalloc.h>
46
47#include <asm/barrier.h>
48#include <asm/cpufeature.h>
49#include <asm/mmu.h>
50#include <asm/sysreg.h>
51
52#define ARM_SPE_BUF_PAD_BYTE 0
53
54struct arm_spe_pmu_buf {
55 int nr_pages;
56 bool snapshot;
57 void *base;
58};
59
60struct arm_spe_pmu {
61 struct pmu pmu;
62 struct platform_device *pdev;
63 cpumask_t supported_cpus;
64 struct hlist_node hotplug_node;
65
66 int irq; /* PPI */
67
68 u16 min_period;
69 u16 counter_sz;
70
71#define SPE_PMU_FEAT_FILT_EVT (1UL << 0)
72#define SPE_PMU_FEAT_FILT_TYP (1UL << 1)
73#define SPE_PMU_FEAT_FILT_LAT (1UL << 2)
74#define SPE_PMU_FEAT_ARCH_INST (1UL << 3)
75#define SPE_PMU_FEAT_LDS (1UL << 4)
76#define SPE_PMU_FEAT_ERND (1UL << 5)
77#define SPE_PMU_FEAT_DEV_PROBED (1UL << 63)
78 u64 features;
79
80 u16 max_record_sz;
81 u16 align;
82 struct perf_output_handle __percpu *handle;
83};
84
85#define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu))
86
87/* Convert a free-running index from perf into an SPE buffer offset */
88#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
89
90/* Keep track of our dynamic hotplug state */
91static enum cpuhp_state arm_spe_pmu_online;
92
93enum arm_spe_pmu_buf_fault_action {
94 SPE_PMU_BUF_FAULT_ACT_SPURIOUS,
95 SPE_PMU_BUF_FAULT_ACT_FATAL,
96 SPE_PMU_BUF_FAULT_ACT_OK,
97};
98
99/* This sysfs gunk was really good fun to write. */
100enum arm_spe_pmu_capabilities {
101 SPE_PMU_CAP_ARCH_INST = 0,
102 SPE_PMU_CAP_ERND,
103 SPE_PMU_CAP_FEAT_MAX,
104 SPE_PMU_CAP_CNT_SZ = SPE_PMU_CAP_FEAT_MAX,
105 SPE_PMU_CAP_MIN_IVAL,
106};
107
108static int arm_spe_pmu_feat_caps[SPE_PMU_CAP_FEAT_MAX] = {
109 [SPE_PMU_CAP_ARCH_INST] = SPE_PMU_FEAT_ARCH_INST,
110 [SPE_PMU_CAP_ERND] = SPE_PMU_FEAT_ERND,
111};
112
113static u32 arm_spe_pmu_cap_get(struct arm_spe_pmu *spe_pmu, int cap)
114{
115 if (cap < SPE_PMU_CAP_FEAT_MAX)
116 return !!(spe_pmu->features & arm_spe_pmu_feat_caps[cap]);
117
118 switch (cap) {
119 case SPE_PMU_CAP_CNT_SZ:
120 return spe_pmu->counter_sz;
121 case SPE_PMU_CAP_MIN_IVAL:
122 return spe_pmu->min_period;
123 default:
124 WARN(1, "unknown cap %d\n", cap);
125 }
126
127 return 0;
128}
129
130static ssize_t arm_spe_pmu_cap_show(struct device *dev,
131 struct device_attribute *attr,
132 char *buf)
133{
134 struct platform_device *pdev = to_platform_device(dev);
135 struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
136 struct dev_ext_attribute *ea =
137 container_of(attr, struct dev_ext_attribute, attr);
138 int cap = (long)ea->var;
139
140 return snprintf(buf, PAGE_SIZE, "%u\n",
141 arm_spe_pmu_cap_get(spe_pmu, cap));
142}
143
144#define SPE_EXT_ATTR_ENTRY(_name, _func, _var) \
145 &((struct dev_ext_attribute[]) { \
146 { __ATTR(_name, S_IRUGO, _func, NULL), (void *)_var } \
147 })[0].attr.attr
148
149#define SPE_CAP_EXT_ATTR_ENTRY(_name, _var) \
150 SPE_EXT_ATTR_ENTRY(_name, arm_spe_pmu_cap_show, _var)
151
152static struct attribute *arm_spe_pmu_cap_attr[] = {
153 SPE_CAP_EXT_ATTR_ENTRY(arch_inst, SPE_PMU_CAP_ARCH_INST),
154 SPE_CAP_EXT_ATTR_ENTRY(ernd, SPE_PMU_CAP_ERND),
155 SPE_CAP_EXT_ATTR_ENTRY(count_size, SPE_PMU_CAP_CNT_SZ),
156 SPE_CAP_EXT_ATTR_ENTRY(min_interval, SPE_PMU_CAP_MIN_IVAL),
157 NULL,
158};
159
160static struct attribute_group arm_spe_pmu_cap_group = {
161 .name = "caps",
162 .attrs = arm_spe_pmu_cap_attr,
163};
164
165/* User ABI */
166#define ATTR_CFG_FLD_ts_enable_CFG config /* PMSCR_EL1.TS */
167#define ATTR_CFG_FLD_ts_enable_LO 0
168#define ATTR_CFG_FLD_ts_enable_HI 0
169#define ATTR_CFG_FLD_pa_enable_CFG config /* PMSCR_EL1.PA */
170#define ATTR_CFG_FLD_pa_enable_LO 1
171#define ATTR_CFG_FLD_pa_enable_HI 1
172#define ATTR_CFG_FLD_pct_enable_CFG config /* PMSCR_EL1.PCT */
173#define ATTR_CFG_FLD_pct_enable_LO 2
174#define ATTR_CFG_FLD_pct_enable_HI 2
175#define ATTR_CFG_FLD_jitter_CFG config /* PMSIRR_EL1.RND */
176#define ATTR_CFG_FLD_jitter_LO 16
177#define ATTR_CFG_FLD_jitter_HI 16
178#define ATTR_CFG_FLD_branch_filter_CFG config /* PMSFCR_EL1.B */
179#define ATTR_CFG_FLD_branch_filter_LO 32
180#define ATTR_CFG_FLD_branch_filter_HI 32
181#define ATTR_CFG_FLD_load_filter_CFG config /* PMSFCR_EL1.LD */
182#define ATTR_CFG_FLD_load_filter_LO 33
183#define ATTR_CFG_FLD_load_filter_HI 33
184#define ATTR_CFG_FLD_store_filter_CFG config /* PMSFCR_EL1.ST */
185#define ATTR_CFG_FLD_store_filter_LO 34
186#define ATTR_CFG_FLD_store_filter_HI 34
187
188#define ATTR_CFG_FLD_event_filter_CFG config1 /* PMSEVFR_EL1 */
189#define ATTR_CFG_FLD_event_filter_LO 0
190#define ATTR_CFG_FLD_event_filter_HI 63
191
192#define ATTR_CFG_FLD_min_latency_CFG config2 /* PMSLATFR_EL1.MINLAT */
193#define ATTR_CFG_FLD_min_latency_LO 0
194#define ATTR_CFG_FLD_min_latency_HI 11
195
196/* Why does everything I do descend into this? */
197#define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \
198 (lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi
199
200#define _GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \
201 __GEN_PMU_FORMAT_ATTR(cfg, lo, hi)
202
203#define GEN_PMU_FORMAT_ATTR(name) \
204 PMU_FORMAT_ATTR(name, \
205 _GEN_PMU_FORMAT_ATTR(ATTR_CFG_FLD_##name##_CFG, \
206 ATTR_CFG_FLD_##name##_LO, \
207 ATTR_CFG_FLD_##name##_HI))
208
209#define _ATTR_CFG_GET_FLD(attr, cfg, lo, hi) \
210 ((((attr)->cfg) >> lo) & GENMASK(hi - lo, 0))
211
212#define ATTR_CFG_GET_FLD(attr, name) \
213 _ATTR_CFG_GET_FLD(attr, \
214 ATTR_CFG_FLD_##name##_CFG, \
215 ATTR_CFG_FLD_##name##_LO, \
216 ATTR_CFG_FLD_##name##_HI)
217
218GEN_PMU_FORMAT_ATTR(ts_enable);
219GEN_PMU_FORMAT_ATTR(pa_enable);
220GEN_PMU_FORMAT_ATTR(pct_enable);
221GEN_PMU_FORMAT_ATTR(jitter);
222GEN_PMU_FORMAT_ATTR(branch_filter);
223GEN_PMU_FORMAT_ATTR(load_filter);
224GEN_PMU_FORMAT_ATTR(store_filter);
225GEN_PMU_FORMAT_ATTR(event_filter);
226GEN_PMU_FORMAT_ATTR(min_latency);
227
228static struct attribute *arm_spe_pmu_formats_attr[] = {
229 &format_attr_ts_enable.attr,
230 &format_attr_pa_enable.attr,
231 &format_attr_pct_enable.attr,
232 &format_attr_jitter.attr,
233 &format_attr_branch_filter.attr,
234 &format_attr_load_filter.attr,
235 &format_attr_store_filter.attr,
236 &format_attr_event_filter.attr,
237 &format_attr_min_latency.attr,
238 NULL,
239};
240
241static struct attribute_group arm_spe_pmu_format_group = {
242 .name = "format",
243 .attrs = arm_spe_pmu_formats_attr,
244};
245
246static ssize_t arm_spe_pmu_get_attr_cpumask(struct device *dev,
247 struct device_attribute *attr,
248 char *buf)
249{
250 struct platform_device *pdev = to_platform_device(dev);
251 struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
252
253 return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus);
254}
255static DEVICE_ATTR(cpumask, S_IRUGO, arm_spe_pmu_get_attr_cpumask, NULL);
256
257static struct attribute *arm_spe_pmu_attrs[] = {
258 &dev_attr_cpumask.attr,
259 NULL,
260};
261
262static struct attribute_group arm_spe_pmu_group = {
263 .attrs = arm_spe_pmu_attrs,
264};
265
266static const struct attribute_group *arm_spe_pmu_attr_groups[] = {
267 &arm_spe_pmu_group,
268 &arm_spe_pmu_cap_group,
269 &arm_spe_pmu_format_group,
270 NULL,
271};
272
273/* Convert between user ABI and register values */
274static u64 arm_spe_event_to_pmscr(struct perf_event *event)
275{
276 struct perf_event_attr *attr = &event->attr;
277 u64 reg = 0;
278
279 reg |= ATTR_CFG_GET_FLD(attr, ts_enable) << SYS_PMSCR_EL1_TS_SHIFT;
280 reg |= ATTR_CFG_GET_FLD(attr, pa_enable) << SYS_PMSCR_EL1_PA_SHIFT;
281 reg |= ATTR_CFG_GET_FLD(attr, pct_enable) << SYS_PMSCR_EL1_PCT_SHIFT;
282
283 if (!attr->exclude_user)
284 reg |= BIT(SYS_PMSCR_EL1_E0SPE_SHIFT);
285
286 if (!attr->exclude_kernel)
287 reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT);
288
289 if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && capable(CAP_SYS_ADMIN))
290 reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT);
291
292 return reg;
293}
294
295static void arm_spe_event_sanitise_period(struct perf_event *event)
296{
297 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
298 u64 period = event->hw.sample_period;
299 u64 max_period = SYS_PMSIRR_EL1_INTERVAL_MASK
300 << SYS_PMSIRR_EL1_INTERVAL_SHIFT;
301
302 if (period < spe_pmu->min_period)
303 period = spe_pmu->min_period;
304 else if (period > max_period)
305 period = max_period;
306 else
307 period &= max_period;
308
309 event->hw.sample_period = period;
310}
311
312static u64 arm_spe_event_to_pmsirr(struct perf_event *event)
313{
314 struct perf_event_attr *attr = &event->attr;
315 u64 reg = 0;
316
317 arm_spe_event_sanitise_period(event);
318
319 reg |= ATTR_CFG_GET_FLD(attr, jitter) << SYS_PMSIRR_EL1_RND_SHIFT;
320 reg |= event->hw.sample_period;
321
322 return reg;
323}
324
325static u64 arm_spe_event_to_pmsfcr(struct perf_event *event)
326{
327 struct perf_event_attr *attr = &event->attr;
328 u64 reg = 0;
329
330 reg |= ATTR_CFG_GET_FLD(attr, load_filter) << SYS_PMSFCR_EL1_LD_SHIFT;
331 reg |= ATTR_CFG_GET_FLD(attr, store_filter) << SYS_PMSFCR_EL1_ST_SHIFT;
332 reg |= ATTR_CFG_GET_FLD(attr, branch_filter) << SYS_PMSFCR_EL1_B_SHIFT;
333
334 if (reg)
335 reg |= BIT(SYS_PMSFCR_EL1_FT_SHIFT);
336
337 if (ATTR_CFG_GET_FLD(attr, event_filter))
338 reg |= BIT(SYS_PMSFCR_EL1_FE_SHIFT);
339
340 if (ATTR_CFG_GET_FLD(attr, min_latency))
341 reg |= BIT(SYS_PMSFCR_EL1_FL_SHIFT);
342
343 return reg;
344}
345
346static u64 arm_spe_event_to_pmsevfr(struct perf_event *event)
347{
348 struct perf_event_attr *attr = &event->attr;
349 return ATTR_CFG_GET_FLD(attr, event_filter);
350}
351
352static u64 arm_spe_event_to_pmslatfr(struct perf_event *event)
353{
354 struct perf_event_attr *attr = &event->attr;
355 return ATTR_CFG_GET_FLD(attr, min_latency)
356 << SYS_PMSLATFR_EL1_MINLAT_SHIFT;
357}
358
359static void arm_spe_pmu_pad_buf(struct perf_output_handle *handle, int len)
360{
361 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
362 u64 head = PERF_IDX2OFF(handle->head, buf);
363
364 memset(buf->base + head, ARM_SPE_BUF_PAD_BYTE, len);
365 if (!buf->snapshot)
366 perf_aux_output_skip(handle, len);
367}
368
369static u64 arm_spe_pmu_next_snapshot_off(struct perf_output_handle *handle)
370{
371 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
372 struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
373 u64 head = PERF_IDX2OFF(handle->head, buf);
374 u64 limit = buf->nr_pages * PAGE_SIZE;
375
376 /*
377 * The trace format isn't parseable in reverse, so clamp
378 * the limit to half of the buffer size in snapshot mode
379 * so that the worst case is half a buffer of records, as
380 * opposed to a single record.
381 */
382 if (head < limit >> 1)
383 limit >>= 1;
384
385 /*
386 * If we're within max_record_sz of the limit, we must
387 * pad, move the head index and recompute the limit.
388 */
389 if (limit - head < spe_pmu->max_record_sz) {
390 arm_spe_pmu_pad_buf(handle, limit - head);
391 handle->head = PERF_IDX2OFF(limit, buf);
392 limit = ((buf->nr_pages * PAGE_SIZE) >> 1) + handle->head;
393 }
394
395 return limit;
396}
397
398static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle)
399{
400 struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
401 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
402 const u64 bufsize = buf->nr_pages * PAGE_SIZE;
403 u64 limit = bufsize;
404 u64 head, tail, wakeup;
405
406 /*
407 * The head can be misaligned for two reasons:
408 *
409 * 1. The hardware left PMBPTR pointing to the first byte after
410 * a record when generating a buffer management event.
411 *
412 * 2. We used perf_aux_output_skip to consume handle->size bytes
413 * and CIRC_SPACE was used to compute the size, which always
414 * leaves one entry free.
415 *
416 * Deal with this by padding to the next alignment boundary and
417 * moving the head index. If we run out of buffer space, we'll
418 * reduce handle->size to zero and end up reporting truncation.
419 */
420 head = PERF_IDX2OFF(handle->head, buf);
421 if (!IS_ALIGNED(head, spe_pmu->align)) {
422 unsigned long delta = roundup(head, spe_pmu->align) - head;
423
424 delta = min(delta, handle->size);
425 arm_spe_pmu_pad_buf(handle, delta);
426 head = PERF_IDX2OFF(handle->head, buf);
427 }
428
429 /* If we've run out of free space, then nothing more to do */
430 if (!handle->size)
431 goto no_space;
432
433 /* Compute the tail and wakeup indices now that we've aligned head */
434 tail = PERF_IDX2OFF(handle->head + handle->size, buf);
435 wakeup = PERF_IDX2OFF(handle->wakeup, buf);
436
437 /*
438 * Avoid clobbering unconsumed data. We know we have space, so
439 * if we see head == tail we know that the buffer is empty. If
440 * head > tail, then there's nothing to clobber prior to
441 * wrapping.
442 */
443 if (head < tail)
444 limit = round_down(tail, PAGE_SIZE);
445
446 /*
447 * Wakeup may be arbitrarily far into the future. If it's not in
448 * the current generation, either we'll wrap before hitting it,
449 * or it's in the past and has been handled already.
450 *
451 * If there's a wakeup before we wrap, arrange to be woken up by
452 * the page boundary following it. Keep the tail boundary if
453 * that's lower.
454 */
455 if (handle->wakeup < (handle->head + handle->size) && head <= wakeup)
456 limit = min(limit, round_up(wakeup, PAGE_SIZE));
457
458 if (limit > head)
459 return limit;
460
461 arm_spe_pmu_pad_buf(handle, handle->size);
462no_space:
463 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
464 perf_aux_output_end(handle, 0);
465 return 0;
466}
467
468static u64 arm_spe_pmu_next_off(struct perf_output_handle *handle)
469{
470 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
471 struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu);
472 u64 limit = __arm_spe_pmu_next_off(handle);
473 u64 head = PERF_IDX2OFF(handle->head, buf);
474
475 /*
476 * If the head has come too close to the end of the buffer,
477 * then pad to the end and recompute the limit.
478 */
479 if (limit && (limit - head < spe_pmu->max_record_sz)) {
480 arm_spe_pmu_pad_buf(handle, limit - head);
481 limit = __arm_spe_pmu_next_off(handle);
482 }
483
484 return limit;
485}
486
487static void arm_spe_perf_aux_output_begin(struct perf_output_handle *handle,
488 struct perf_event *event)
489{
490 u64 base, limit;
491 struct arm_spe_pmu_buf *buf;
492
493 /* Start a new aux session */
494 buf = perf_aux_output_begin(handle, event);
495 if (!buf) {
496 event->hw.state |= PERF_HES_STOPPED;
497 /*
498 * We still need to clear the limit pointer, since the
499 * profiler might only be disabled by virtue of a fault.
500 */
501 limit = 0;
502 goto out_write_limit;
503 }
504
505 limit = buf->snapshot ? arm_spe_pmu_next_snapshot_off(handle)
506 : arm_spe_pmu_next_off(handle);
507 if (limit)
508 limit |= BIT(SYS_PMBLIMITR_EL1_E_SHIFT);
509
510 limit += (u64)buf->base;
511 base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf);
512 write_sysreg_s(base, SYS_PMBPTR_EL1);
513
514out_write_limit:
515 write_sysreg_s(limit, SYS_PMBLIMITR_EL1);
516}
517
518static void arm_spe_perf_aux_output_end(struct perf_output_handle *handle)
519{
520 struct arm_spe_pmu_buf *buf = perf_get_aux(handle);
521 u64 offset, size;
522
523 offset = read_sysreg_s(SYS_PMBPTR_EL1) - (u64)buf->base;
524 size = offset - PERF_IDX2OFF(handle->head, buf);
525
526 if (buf->snapshot)
527 handle->head = offset;
528
529 perf_aux_output_end(handle, size);
530}
531
532static void arm_spe_pmu_disable_and_drain_local(void)
533{
534 /* Disable profiling at EL0 and EL1 */
535 write_sysreg_s(0, SYS_PMSCR_EL1);
536 isb();
537
538 /* Drain any buffered data */
539 psb_csync();
540 dsb(nsh);
541
542 /* Disable the profiling buffer */
543 write_sysreg_s(0, SYS_PMBLIMITR_EL1);
544 isb();
545}
546
547/* IRQ handling */
548static enum arm_spe_pmu_buf_fault_action
549arm_spe_pmu_buf_get_fault_act(struct perf_output_handle *handle)
550{
551 const char *err_str;
552 u64 pmbsr;
553 enum arm_spe_pmu_buf_fault_action ret;
554
555 /*
556 * Ensure new profiling data is visible to the CPU and any external
557 * aborts have been resolved.
558 */
559 psb_csync();
560 dsb(nsh);
561
562 /* Ensure hardware updates to PMBPTR_EL1 are visible */
563 isb();
564
565 /* Service required? */
566 pmbsr = read_sysreg_s(SYS_PMBSR_EL1);
567 if (!(pmbsr & BIT(SYS_PMBSR_EL1_S_SHIFT)))
568 return SPE_PMU_BUF_FAULT_ACT_SPURIOUS;
569
570 /*
571 * If we've lost data, disable profiling and also set the PARTIAL
572 * flag to indicate that the last record is corrupted.
573 */
574 if (pmbsr & BIT(SYS_PMBSR_EL1_DL_SHIFT))
575 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED |
576 PERF_AUX_FLAG_PARTIAL);
577
578 /* Report collisions to userspace so that it can up the period */
579 if (pmbsr & BIT(SYS_PMBSR_EL1_COLL_SHIFT))
580 perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
581
582 /* We only expect buffer management events */
583 switch (pmbsr & (SYS_PMBSR_EL1_EC_MASK << SYS_PMBSR_EL1_EC_SHIFT)) {
584 case SYS_PMBSR_EL1_EC_BUF:
585 /* Handled below */
586 break;
587 case SYS_PMBSR_EL1_EC_FAULT_S1:
588 case SYS_PMBSR_EL1_EC_FAULT_S2:
589 err_str = "Unexpected buffer fault";
590 goto out_err;
591 default:
592 err_str = "Unknown error code";
593 goto out_err;
594 }
595
596 /* Buffer management event */
597 switch (pmbsr &
598 (SYS_PMBSR_EL1_BUF_BSC_MASK << SYS_PMBSR_EL1_BUF_BSC_SHIFT)) {
599 case SYS_PMBSR_EL1_BUF_BSC_FULL:
600 ret = SPE_PMU_BUF_FAULT_ACT_OK;
601 goto out_stop;
602 default:
603 err_str = "Unknown buffer status code";
604 }
605
606out_err:
607 pr_err_ratelimited("%s on CPU %d [PMBSR=0x%016llx, PMBPTR=0x%016llx, PMBLIMITR=0x%016llx]\n",
608 err_str, smp_processor_id(), pmbsr,
609 read_sysreg_s(SYS_PMBPTR_EL1),
610 read_sysreg_s(SYS_PMBLIMITR_EL1));
611 ret = SPE_PMU_BUF_FAULT_ACT_FATAL;
612
613out_stop:
614 arm_spe_perf_aux_output_end(handle);
615 return ret;
616}
617
618static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev)
619{
620 struct perf_output_handle *handle = dev;
621 struct perf_event *event = handle->event;
622 enum arm_spe_pmu_buf_fault_action act;
623
624 if (!perf_get_aux(handle))
625 return IRQ_NONE;
626
627 act = arm_spe_pmu_buf_get_fault_act(handle);
628 if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
629 return IRQ_NONE;
630
631 /*
632 * Ensure perf callbacks have completed, which may disable the
633 * profiling buffer in response to a TRUNCATION flag.
634 */
635 irq_work_run();
636
637 switch (act) {
638 case SPE_PMU_BUF_FAULT_ACT_FATAL:
639 /*
640 * If a fatal exception occurred then leaving the profiling
641 * buffer enabled is a recipe waiting to happen. Since
642 * fatal faults don't always imply truncation, make sure
643 * that the profiling buffer is disabled explicitly before
644 * clearing the syndrome register.
645 */
646 arm_spe_pmu_disable_and_drain_local();
647 break;
648 case SPE_PMU_BUF_FAULT_ACT_OK:
649 /*
650 * We handled the fault (the buffer was full), so resume
651 * profiling as long as we didn't detect truncation.
652 * PMBPTR might be misaligned, but we'll burn that bridge
653 * when we get to it.
654 */
655 if (!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)) {
656 arm_spe_perf_aux_output_begin(handle, event);
657 isb();
658 }
659 break;
660 case SPE_PMU_BUF_FAULT_ACT_SPURIOUS:
661 /* We've seen you before, but GCC has the memory of a sieve. */
662 break;
663 }
664
665 /* The buffer pointers are now sane, so resume profiling. */
666 write_sysreg_s(0, SYS_PMBSR_EL1);
667 return IRQ_HANDLED;
668}
669
670/* Perf callbacks */
671static int arm_spe_pmu_event_init(struct perf_event *event)
672{
673 u64 reg;
674 struct perf_event_attr *attr = &event->attr;
675 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
676
677 /* This is, of course, deeply driver-specific */
678 if (attr->type != event->pmu->type)
679 return -ENOENT;
680
681 if (event->cpu >= 0 &&
682 !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus))
683 return -ENOENT;
684
685 if (arm_spe_event_to_pmsevfr(event) & SYS_PMSEVFR_EL1_RES0)
686 return -EOPNOTSUPP;
687
688 if (attr->exclude_idle)
689 return -EOPNOTSUPP;
690
691 /*
692 * Feedback-directed frequency throttling doesn't work when we
693 * have a buffer of samples. We'd need to manually count the
694 * samples in the buffer when it fills up and adjust the event
695 * count to reflect that. Instead, just force the user to specify
696 * a sample period.
697 */
698 if (attr->freq)
699 return -EINVAL;
700
701 reg = arm_spe_event_to_pmsfcr(event);
702 if ((reg & BIT(SYS_PMSFCR_EL1_FE_SHIFT)) &&
703 !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT))
704 return -EOPNOTSUPP;
705
706 if ((reg & BIT(SYS_PMSFCR_EL1_FT_SHIFT)) &&
707 !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP))
708 return -EOPNOTSUPP;
709
710 if ((reg & BIT(SYS_PMSFCR_EL1_FL_SHIFT)) &&
711 !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
712 return -EOPNOTSUPP;
713
714 reg = arm_spe_event_to_pmscr(event);
715 if (!capable(CAP_SYS_ADMIN) &&
716 (reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) |
717 BIT(SYS_PMSCR_EL1_CX_SHIFT) |
718 BIT(SYS_PMSCR_EL1_PCT_SHIFT))))
719 return -EACCES;
720
721 return 0;
722}
723
724static void arm_spe_pmu_start(struct perf_event *event, int flags)
725{
726 u64 reg;
727 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
728 struct hw_perf_event *hwc = &event->hw;
729 struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
730
731 hwc->state = 0;
732 arm_spe_perf_aux_output_begin(handle, event);
733 if (hwc->state)
734 return;
735
736 reg = arm_spe_event_to_pmsfcr(event);
737 write_sysreg_s(reg, SYS_PMSFCR_EL1);
738
739 reg = arm_spe_event_to_pmsevfr(event);
740 write_sysreg_s(reg, SYS_PMSEVFR_EL1);
741
742 reg = arm_spe_event_to_pmslatfr(event);
743 write_sysreg_s(reg, SYS_PMSLATFR_EL1);
744
745 if (flags & PERF_EF_RELOAD) {
746 reg = arm_spe_event_to_pmsirr(event);
747 write_sysreg_s(reg, SYS_PMSIRR_EL1);
748 isb();
749 reg = local64_read(&hwc->period_left);
750 write_sysreg_s(reg, SYS_PMSICR_EL1);
751 }
752
753 reg = arm_spe_event_to_pmscr(event);
754 isb();
755 write_sysreg_s(reg, SYS_PMSCR_EL1);
756}
757
758static void arm_spe_pmu_stop(struct perf_event *event, int flags)
759{
760 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
761 struct hw_perf_event *hwc = &event->hw;
762 struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle);
763
764 /* If we're already stopped, then nothing to do */
765 if (hwc->state & PERF_HES_STOPPED)
766 return;
767
768 /* Stop all trace generation */
769 arm_spe_pmu_disable_and_drain_local();
770
771 if (flags & PERF_EF_UPDATE) {
772 /*
773 * If there's a fault pending then ensure we contain it
774 * to this buffer, since we might be on the context-switch
775 * path.
776 */
777 if (perf_get_aux(handle)) {
778 enum arm_spe_pmu_buf_fault_action act;
779
780 act = arm_spe_pmu_buf_get_fault_act(handle);
781 if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS)
782 arm_spe_perf_aux_output_end(handle);
783 else
784 write_sysreg_s(0, SYS_PMBSR_EL1);
785 }
786
787 /*
788 * This may also contain ECOUNT, but nobody else should
789 * be looking at period_left, since we forbid frequency
790 * based sampling.
791 */
792 local64_set(&hwc->period_left, read_sysreg_s(SYS_PMSICR_EL1));
793 hwc->state |= PERF_HES_UPTODATE;
794 }
795
796 hwc->state |= PERF_HES_STOPPED;
797}
798
799static int arm_spe_pmu_add(struct perf_event *event, int flags)
800{
801 int ret = 0;
802 struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
803 struct hw_perf_event *hwc = &event->hw;
804 int cpu = event->cpu == -1 ? smp_processor_id() : event->cpu;
805
806 if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
807 return -ENOENT;
808
809 hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
810
811 if (flags & PERF_EF_START) {
812 arm_spe_pmu_start(event, PERF_EF_RELOAD);
813 if (hwc->state & PERF_HES_STOPPED)
814 ret = -EINVAL;
815 }
816
817 return ret;
818}
819
820static void arm_spe_pmu_del(struct perf_event *event, int flags)
821{
822 arm_spe_pmu_stop(event, PERF_EF_UPDATE);
823}
824
825static void arm_spe_pmu_read(struct perf_event *event)
826{
827}
828
829static void *arm_spe_pmu_setup_aux(int cpu, void **pages, int nr_pages,
830 bool snapshot)
831{
832 int i;
833 struct page **pglist;
834 struct arm_spe_pmu_buf *buf;
835
836 /* We need at least two pages for this to work. */
837 if (nr_pages < 2)
838 return NULL;
839
840 /*
841 * We require an even number of pages for snapshot mode, so that
842 * we can effectively treat the buffer as consisting of two equal
843 * parts and give userspace a fighting chance of getting some
844 * useful data out of it.
845 */
846 if (!nr_pages || (snapshot && (nr_pages & 1)))
847 return NULL;
848
849 if (cpu == -1)
850 cpu = raw_smp_processor_id();
851
852 buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, cpu_to_node(cpu));
853 if (!buf)
854 return NULL;
855
856 pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
857 if (!pglist)
858 goto out_free_buf;
859
860 for (i = 0; i < nr_pages; ++i) {
861 struct page *page = virt_to_page(pages[i]);
862
863 if (PagePrivate(page)) {
864 pr_warn("unexpected high-order page for auxbuf!");
865 goto out_free_pglist;
866 }
867
868 pglist[i] = virt_to_page(pages[i]);
869 }
870
871 buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL);
872 if (!buf->base)
873 goto out_free_pglist;
874
875 buf->nr_pages = nr_pages;
876 buf->snapshot = snapshot;
877
878 kfree(pglist);
879 return buf;
880
881out_free_pglist:
882 kfree(pglist);
883out_free_buf:
884 kfree(buf);
885 return NULL;
886}
887
888static void arm_spe_pmu_free_aux(void *aux)
889{
890 struct arm_spe_pmu_buf *buf = aux;
891
892 vunmap(buf->base);
893 kfree(buf);
894}
895
896/* Initialisation and teardown functions */
897static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu)
898{
899 static atomic_t pmu_idx = ATOMIC_INIT(-1);
900
901 int idx;
902 char *name;
903 struct device *dev = &spe_pmu->pdev->dev;
904
905 spe_pmu->pmu = (struct pmu) {
906 .module = THIS_MODULE,
907 .capabilities = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
908 .attr_groups = arm_spe_pmu_attr_groups,
909 /*
910 * We hitch a ride on the software context here, so that
911 * we can support per-task profiling (which is not possible
912 * with the invalid context as it doesn't get sched callbacks).
913 * This requires that userspace either uses a dummy event for
914 * perf_event_open, since the aux buffer is not setup until
915 * a subsequent mmap, or creates the profiling event in a
916 * disabled state and explicitly PERF_EVENT_IOC_ENABLEs it
917 * once the buffer has been created.
918 */
919 .task_ctx_nr = perf_sw_context,
920 .event_init = arm_spe_pmu_event_init,
921 .add = arm_spe_pmu_add,
922 .del = arm_spe_pmu_del,
923 .start = arm_spe_pmu_start,
924 .stop = arm_spe_pmu_stop,
925 .read = arm_spe_pmu_read,
926 .setup_aux = arm_spe_pmu_setup_aux,
927 .free_aux = arm_spe_pmu_free_aux,
928 };
929
930 idx = atomic_inc_return(&pmu_idx);
931 name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx);
932 return perf_pmu_register(&spe_pmu->pmu, name, -1);
933}
934
935static void arm_spe_pmu_perf_destroy(struct arm_spe_pmu *spe_pmu)
936{
937 perf_pmu_unregister(&spe_pmu->pmu);
938}
939
940static void __arm_spe_pmu_dev_probe(void *info)
941{
942 int fld;
943 u64 reg;
944 struct arm_spe_pmu *spe_pmu = info;
945 struct device *dev = &spe_pmu->pdev->dev;
946
947 fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64DFR0_EL1),
948 ID_AA64DFR0_PMSVER_SHIFT);
949 if (!fld) {
950 dev_err(dev,
951 "unsupported ID_AA64DFR0_EL1.PMSVer [%d] on CPU %d\n",
952 fld, smp_processor_id());
953 return;
954 }
955
956 /* Read PMBIDR first to determine whether or not we have access */
957 reg = read_sysreg_s(SYS_PMBIDR_EL1);
958 if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT)) {
959 dev_err(dev,
960 "profiling buffer owned by higher exception level\n");
961 return;
962 }
963
964 /* Minimum alignment. If it's out-of-range, then fail the probe */
965 fld = reg >> SYS_PMBIDR_EL1_ALIGN_SHIFT & SYS_PMBIDR_EL1_ALIGN_MASK;
966 spe_pmu->align = 1 << fld;
967 if (spe_pmu->align > SZ_2K) {
968 dev_err(dev, "unsupported PMBIDR.Align [%d] on CPU %d\n",
969 fld, smp_processor_id());
970 return;
971 }
972
973 /* It's now safe to read PMSIDR and figure out what we've got */
974 reg = read_sysreg_s(SYS_PMSIDR_EL1);
975 if (reg & BIT(SYS_PMSIDR_EL1_FE_SHIFT))
976 spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT;
977
978 if (reg & BIT(SYS_PMSIDR_EL1_FT_SHIFT))
979 spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP;
980
981 if (reg & BIT(SYS_PMSIDR_EL1_FL_SHIFT))
982 spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT;
983
984 if (reg & BIT(SYS_PMSIDR_EL1_ARCHINST_SHIFT))
985 spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST;
986
987 if (reg & BIT(SYS_PMSIDR_EL1_LDS_SHIFT))
988 spe_pmu->features |= SPE_PMU_FEAT_LDS;
989
990 if (reg & BIT(SYS_PMSIDR_EL1_ERND_SHIFT))
991 spe_pmu->features |= SPE_PMU_FEAT_ERND;
992
993 /* This field has a spaced out encoding, so just use a look-up */
994 fld = reg >> SYS_PMSIDR_EL1_INTERVAL_SHIFT & SYS_PMSIDR_EL1_INTERVAL_MASK;
995 switch (fld) {
996 case 0:
997 spe_pmu->min_period = 256;
998 break;
999 case 2:
1000 spe_pmu->min_period = 512;
1001 break;
1002 case 3:
1003 spe_pmu->min_period = 768;
1004 break;
1005 case 4:
1006 spe_pmu->min_period = 1024;
1007 break;
1008 case 5:
1009 spe_pmu->min_period = 1536;
1010 break;
1011 case 6:
1012 spe_pmu->min_period = 2048;
1013 break;
1014 case 7:
1015 spe_pmu->min_period = 3072;
1016 break;
1017 default:
1018 dev_warn(dev, "unknown PMSIDR_EL1.Interval [%d]; assuming 8\n",
1019 fld);
1020 /* Fallthrough */
1021 case 8:
1022 spe_pmu->min_period = 4096;
1023 }
1024
1025 /* Maximum record size. If it's out-of-range, then fail the probe */
1026 fld = reg >> SYS_PMSIDR_EL1_MAXSIZE_SHIFT & SYS_PMSIDR_EL1_MAXSIZE_MASK;
1027 spe_pmu->max_record_sz = 1 << fld;
1028 if (spe_pmu->max_record_sz > SZ_2K || spe_pmu->max_record_sz < 16) {
1029 dev_err(dev, "unsupported PMSIDR_EL1.MaxSize [%d] on CPU %d\n",
1030 fld, smp_processor_id());
1031 return;
1032 }
1033
1034 fld = reg >> SYS_PMSIDR_EL1_COUNTSIZE_SHIFT & SYS_PMSIDR_EL1_COUNTSIZE_MASK;
1035 switch (fld) {
1036 default:
1037 dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n",
1038 fld);
1039 /* Fallthrough */
1040 case 2:
1041 spe_pmu->counter_sz = 12;
1042 }
1043
1044 dev_info(dev,
1045 "probed for CPUs %*pbl [max_record_sz %u, align %u, features 0x%llx]\n",
1046 cpumask_pr_args(&spe_pmu->supported_cpus),
1047 spe_pmu->max_record_sz, spe_pmu->align, spe_pmu->features);
1048
1049 spe_pmu->features |= SPE_PMU_FEAT_DEV_PROBED;
1050 return;
1051}
1052
1053static void __arm_spe_pmu_reset_local(void)
1054{
1055 /*
1056 * This is probably overkill, as we have no idea where we're
1057 * draining any buffered data to...
1058 */
1059 arm_spe_pmu_disable_and_drain_local();
1060
1061 /* Reset the buffer base pointer */
1062 write_sysreg_s(0, SYS_PMBPTR_EL1);
1063 isb();
1064
1065 /* Clear any pending management interrupts */
1066 write_sysreg_s(0, SYS_PMBSR_EL1);
1067 isb();
1068}
1069
1070static void __arm_spe_pmu_setup_one(void *info)
1071{
1072 struct arm_spe_pmu *spe_pmu = info;
1073
1074 __arm_spe_pmu_reset_local();
1075 enable_percpu_irq(spe_pmu->irq, IRQ_TYPE_NONE);
1076}
1077
1078static void __arm_spe_pmu_stop_one(void *info)
1079{
1080 struct arm_spe_pmu *spe_pmu = info;
1081
1082 disable_percpu_irq(spe_pmu->irq);
1083 __arm_spe_pmu_reset_local();
1084}
1085
1086static int arm_spe_pmu_cpu_startup(unsigned int cpu, struct hlist_node *node)
1087{
1088 struct arm_spe_pmu *spe_pmu;
1089
1090 spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1091 if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1092 return 0;
1093
1094 __arm_spe_pmu_setup_one(spe_pmu);
1095 return 0;
1096}
1097
1098static int arm_spe_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)
1099{
1100 struct arm_spe_pmu *spe_pmu;
1101
1102 spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node);
1103 if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus))
1104 return 0;
1105
1106 __arm_spe_pmu_stop_one(spe_pmu);
1107 return 0;
1108}
1109
1110static int arm_spe_pmu_dev_init(struct arm_spe_pmu *spe_pmu)
1111{
1112 int ret;
1113 cpumask_t *mask = &spe_pmu->supported_cpus;
1114
1115 /* Make sure we probe the hardware on a relevant CPU */
1116 ret = smp_call_function_any(mask, __arm_spe_pmu_dev_probe, spe_pmu, 1);
1117 if (ret || !(spe_pmu->features & SPE_PMU_FEAT_DEV_PROBED))
1118 return -ENXIO;
1119
1120 /* Request our PPIs (note that the IRQ is still disabled) */
1121 ret = request_percpu_irq(spe_pmu->irq, arm_spe_pmu_irq_handler, DRVNAME,
1122 spe_pmu->handle);
1123 if (ret)
1124 return ret;
1125
1126 /*
1127 * Register our hotplug notifier now so we don't miss any events.
1128 * This will enable the IRQ for any supported CPUs that are already
1129 * up.
1130 */
1131 ret = cpuhp_state_add_instance(arm_spe_pmu_online,
1132 &spe_pmu->hotplug_node);
1133 if (ret)
1134 free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1135
1136 return ret;
1137}
1138
1139static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu)
1140{
1141 cpuhp_state_remove_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node);
1142 free_percpu_irq(spe_pmu->irq, spe_pmu->handle);
1143}
1144
1145/* Driver and device probing */
1146static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu)
1147{
1148 struct platform_device *pdev = spe_pmu->pdev;
1149 int irq = platform_get_irq(pdev, 0);
1150
1151 if (irq < 0) {
1152 dev_err(&pdev->dev, "failed to get IRQ (%d)\n", irq);
1153 return -ENXIO;
1154 }
1155
1156 if (!irq_is_percpu(irq)) {
1157 dev_err(&pdev->dev, "expected PPI but got SPI (%d)\n", irq);
1158 return -EINVAL;
1159 }
1160
1161 if (irq_get_percpu_devid_partition(irq, &spe_pmu->supported_cpus)) {
1162 dev_err(&pdev->dev, "failed to get PPI partition (%d)\n", irq);
1163 return -EINVAL;
1164 }
1165
1166 spe_pmu->irq = irq;
1167 return 0;
1168}
1169
1170static const struct of_device_id arm_spe_pmu_of_match[] = {
1171 { .compatible = "arm,statistical-profiling-extension-v1", .data = (void *)1 },
1172 { /* Sentinel */ },
1173};
1174
1175static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev)
1176{
1177 int ret;
1178 struct arm_spe_pmu *spe_pmu;
1179 struct device *dev = &pdev->dev;
1180
1181 /*
1182 * If kernelspace is unmapped when running at EL0, then the SPE
1183 * buffer will fault and prematurely terminate the AUX session.
1184 */
1185 if (arm64_kernel_unmapped_at_el0()) {
1186 dev_warn_once(dev, "profiling buffer inaccessible. Try passing \"kpti=off\" on the kernel command line\n");
1187 return -EPERM;
1188 }
1189
1190 spe_pmu = devm_kzalloc(dev, sizeof(*spe_pmu), GFP_KERNEL);
1191 if (!spe_pmu) {
1192 dev_err(dev, "failed to allocate spe_pmu\n");
1193 return -ENOMEM;
1194 }
1195
1196 spe_pmu->handle = alloc_percpu(typeof(*spe_pmu->handle));
1197 if (!spe_pmu->handle)
1198 return -ENOMEM;
1199
1200 spe_pmu->pdev = pdev;
1201 platform_set_drvdata(pdev, spe_pmu);
1202
1203 ret = arm_spe_pmu_irq_probe(spe_pmu);
1204 if (ret)
1205 goto out_free_handle;
1206
1207 ret = arm_spe_pmu_dev_init(spe_pmu);
1208 if (ret)
1209 goto out_free_handle;
1210
1211 ret = arm_spe_pmu_perf_init(spe_pmu);
1212 if (ret)
1213 goto out_teardown_dev;
1214
1215 return 0;
1216
1217out_teardown_dev:
1218 arm_spe_pmu_dev_teardown(spe_pmu);
1219out_free_handle:
1220 free_percpu(spe_pmu->handle);
1221 return ret;
1222}
1223
1224static int arm_spe_pmu_device_remove(struct platform_device *pdev)
1225{
1226 struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev);
1227
1228 arm_spe_pmu_perf_destroy(spe_pmu);
1229 arm_spe_pmu_dev_teardown(spe_pmu);
1230 free_percpu(spe_pmu->handle);
1231 return 0;
1232}
1233
1234static struct platform_driver arm_spe_pmu_driver = {
1235 .driver = {
1236 .name = DRVNAME,
1237 .of_match_table = of_match_ptr(arm_spe_pmu_of_match),
1238 },
1239 .probe = arm_spe_pmu_device_dt_probe,
1240 .remove = arm_spe_pmu_device_remove,
1241};
1242
1243static int __init arm_spe_pmu_init(void)
1244{
1245 int ret;
1246
1247 ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
1248 arm_spe_pmu_cpu_startup,
1249 arm_spe_pmu_cpu_teardown);
1250 if (ret < 0)
1251 return ret;
1252 arm_spe_pmu_online = ret;
1253
1254 ret = platform_driver_register(&arm_spe_pmu_driver);
1255 if (ret)
1256 cpuhp_remove_multi_state(arm_spe_pmu_online);
1257
1258 return ret;
1259}
1260
1261static void __exit arm_spe_pmu_exit(void)
1262{
1263 platform_driver_unregister(&arm_spe_pmu_driver);
1264 cpuhp_remove_multi_state(arm_spe_pmu_online);
1265}
1266
1267module_init(arm_spe_pmu_init);
1268module_exit(arm_spe_pmu_exit);
1269
1270MODULE_DESCRIPTION("Perf driver for the ARMv8.2 Statistical Profiling Extension");
1271MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
1272MODULE_LICENSE("GPL v2");