// SPDX-License-Identifier: GPL-2.0+ // // Linux performance counter support for ARC CPUs. // This code is inspired by the perf support of various other architectures. // // Copyright (C) 2013-2018 Synopsys, Inc. (www.synopsys.com) #include #include #include #include #include #include #include #include /* HW holds 8 symbols + one for null terminator */ #define ARCPMU_EVENT_NAME_LEN 9 enum arc_pmu_attr_groups { ARCPMU_ATTR_GR_EVENTS, ARCPMU_ATTR_GR_FORMATS, ARCPMU_NR_ATTR_GR }; struct arc_pmu_raw_event_entry { char name[ARCPMU_EVENT_NAME_LEN]; }; struct arc_pmu { struct pmu pmu; unsigned int irq; int n_counters; int n_events; u64 max_period; int ev_hw_idx[PERF_COUNT_ARC_HW_MAX]; struct arc_pmu_raw_event_entry *raw_entry; struct attribute **attrs; struct perf_pmu_events_attr *attr; const struct attribute_group *attr_groups[ARCPMU_NR_ATTR_GR + 1]; }; struct arc_pmu_cpu { /* * A 1 bit for an index indicates that the counter is being used for * an event. A 0 means that the counter can be used. */ unsigned long used_mask[BITS_TO_LONGS(ARC_PERF_MAX_COUNTERS)]; /* * The events that are active on the PMU for the given index. */ struct perf_event *act_counter[ARC_PERF_MAX_COUNTERS]; }; struct arc_callchain_trace { int depth; void *perf_stuff; }; static int callchain_trace(unsigned int addr, void *data) { struct arc_callchain_trace *ctrl = data; struct perf_callchain_entry_ctx *entry = ctrl->perf_stuff; perf_callchain_store(entry, addr); if (ctrl->depth++ < 3) return 0; return -1; } void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { struct arc_callchain_trace ctrl = { .depth = 0, .perf_stuff = entry, }; arc_unwind_core(NULL, regs, callchain_trace, &ctrl); } void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { /* * User stack can't be unwound trivially with kernel dwarf unwinder * So for now just record the user PC */ perf_callchain_store(entry, instruction_pointer(regs)); } static struct arc_pmu *arc_pmu; static DEFINE_PER_CPU(struct arc_pmu_cpu, arc_pmu_cpu); /* read counter #idx; note that counter# != event# on ARC! */ static u64 arc_pmu_read_counter(int idx) { u32 tmp; u64 result; /* * ARC supports making 'snapshots' of the counters, so we don't * need to care about counters wrapping to 0 underneath our feet */ write_aux_reg(ARC_REG_PCT_INDEX, idx); tmp = read_aux_reg(ARC_REG_PCT_CONTROL); write_aux_reg(ARC_REG_PCT_CONTROL, tmp | ARC_REG_PCT_CONTROL_SN); result = (u64) (read_aux_reg(ARC_REG_PCT_SNAPH)) << 32; result |= read_aux_reg(ARC_REG_PCT_SNAPL); return result; } static void arc_perf_event_update(struct perf_event *event, struct hw_perf_event *hwc, int idx) { u64 prev_raw_count = local64_read(&hwc->prev_count); u64 new_raw_count = arc_pmu_read_counter(idx); s64 delta = new_raw_count - prev_raw_count; /* * We aren't afraid of hwc->prev_count changing beneath our feet * because there's no way for us to re-enter this function anytime. */ local64_set(&hwc->prev_count, new_raw_count); local64_add(delta, &event->count); local64_sub(delta, &hwc->period_left); } static void arc_pmu_read(struct perf_event *event) { arc_perf_event_update(event, &event->hw, event->hw.idx); } static int arc_pmu_cache_event(u64 config) { unsigned int cache_type, cache_op, cache_result; int ret; cache_type = (config >> 0) & 0xff; cache_op = (config >> 8) & 0xff; cache_result = (config >> 16) & 0xff; if (cache_type >= PERF_COUNT_HW_CACHE_MAX) return -EINVAL; if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX) return -EINVAL; if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX) return -EINVAL; ret = arc_pmu_cache_map[cache_type][cache_op][cache_result]; if (ret == CACHE_OP_UNSUPPORTED) return -ENOENT; pr_debug("init cache event: type/op/result %d/%d/%d with h/w %d \'%s\'\n", cache_type, cache_op, cache_result, ret, arc_pmu_ev_hw_map[ret]); return ret; } /* initializes hw_perf_event structure if event is supported */ static int arc_pmu_event_init(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; int ret; if (!is_sampling_event(event)) { hwc->sample_period = arc_pmu->max_period; hwc->last_period = hwc->sample_period; local64_set(&hwc->period_left, hwc->sample_period); } hwc->config = 0; if (is_isa_arcv2()) { /* "exclude user" means "count only kernel" */ if (event->attr.exclude_user) hwc->config |= ARC_REG_PCT_CONFIG_KERN; /* "exclude kernel" means "count only user" */ if (event->attr.exclude_kernel) hwc->config |= ARC_REG_PCT_CONFIG_USER; } switch (event->attr.type) { case PERF_TYPE_HARDWARE: if (event->attr.config >= PERF_COUNT_HW_MAX) return -ENOENT; if (arc_pmu->ev_hw_idx[event->attr.config] < 0) return -ENOENT; hwc->config |= arc_pmu->ev_hw_idx[event->attr.config]; pr_debug("init event %d with h/w %08x \'%s\'\n", (int)event->attr.config, (int)hwc->config, arc_pmu_ev_hw_map[event->attr.config]); return 0; case PERF_TYPE_HW_CACHE: ret = arc_pmu_cache_event(event->attr.config); if (ret < 0) return ret; hwc->config |= arc_pmu->ev_hw_idx[ret]; pr_debug("init cache event with h/w %08x \'%s\'\n", (int)hwc->config, arc_pmu_ev_hw_map[ret]); return 0; case PERF_TYPE_RAW: if (event->attr.config >= arc_pmu->n_events) return -ENOENT; hwc->config |= event->attr.config; pr_debug("init raw event with idx %lld \'%s\'\n", event->attr.config, arc_pmu->raw_entry[event->attr.config].name); return 0; default: return -ENOENT; } } /* starts all counters */ static void arc_pmu_enable(struct pmu *pmu) { u32 tmp; tmp = read_aux_reg(ARC_REG_PCT_CONTROL); write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x1); } /* stops all counters */ static void arc_pmu_disable(struct pmu *pmu) { u32 tmp; tmp = read_aux_reg(ARC_REG_PCT_CONTROL); write_aux_reg(ARC_REG_PCT_CONTROL, (tmp & 0xffff0000) | 0x0); } static int arc_pmu_event_set_period(struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; s64 left = local64_read(&hwc->period_left); s64 period = hwc->sample_period; int idx = hwc->idx; int overflow = 0; u64 value; if (unlikely(left <= -period)) { /* left underflowed by more than period. */ left = period; local64_set(&hwc->period_left, left); hwc->last_period = period; overflow = 1; } else if (unlikely(left <= 0)) { /* left underflowed by less than period. */ left += period; local64_set(&hwc->period_left, left); hwc->last_period = period; overflow = 1; } if (left > arc_pmu->max_period) left = arc_pmu->max_period; value = arc_pmu->max_period - left; local64_set(&hwc->prev_count, value); /* Select counter */ write_aux_reg(ARC_REG_PCT_INDEX, idx); /* Write value */ write_aux_reg(ARC_REG_PCT_COUNTL, lower_32_bits(value)); write_aux_reg(ARC_REG_PCT_COUNTH, upper_32_bits(value)); perf_event_update_userpage(event); return overflow; } /* * Assigns hardware counter to hardware condition. * Note that there is no separate start/stop mechanism; * stopping is achieved by assigning the 'never' condition */ static void arc_pmu_start(struct perf_event *event, int flags) { struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; if (WARN_ON_ONCE(idx == -1)) return; if (flags & PERF_EF_RELOAD) WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE)); hwc->state = 0; arc_pmu_event_set_period(event); /* Enable interrupt for this counter */ if (is_sampling_event(event)) write_aux_reg(ARC_REG_PCT_INT_CTRL, read_aux_reg(ARC_REG_PCT_INT_CTRL) | BIT(idx)); /* enable ARC pmu here */ write_aux_reg(ARC_REG_PCT_INDEX, idx); /* counter # */ write_aux_reg(ARC_REG_PCT_CONFIG, hwc->config); /* condition */ } static void arc_pmu_stop(struct perf_event *event, int flags) { struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; /* Disable interrupt for this counter */ if (is_sampling_event(event)) { /* * Reset interrupt flag by writing of 1. This is required * to make sure pending interrupt was not left. */ write_aux_reg(ARC_REG_PCT_INT_ACT, BIT(idx)); write_aux_reg(ARC_REG_PCT_INT_CTRL, read_aux_reg(ARC_REG_PCT_INT_CTRL) & ~BIT(idx)); } if (!(event->hw.state & PERF_HES_STOPPED)) { /* stop ARC pmu here */ write_aux_reg(ARC_REG_PCT_INDEX, idx); /* condition code #0 is always "never" */ write_aux_reg(ARC_REG_PCT_CONFIG, 0); event->hw.state |= PERF_HES_STOPPED; } if ((flags & PERF_EF_UPDATE) && !(event->hw.state & PERF_HES_UPTODATE)) { arc_perf_event_update(event, &event->hw, idx); event->hw.state |= PERF_HES_UPTODATE; } } static void arc_pmu_del(struct perf_event *event, int flags) { struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu); arc_pmu_stop(event, PERF_EF_UPDATE); __clear_bit(event->hw.idx, pmu_cpu->used_mask); pmu_cpu->act_counter[event->hw.idx] = 0; perf_event_update_userpage(event); } /* allocate hardware counter and optionally start counting */ static int arc_pmu_add(struct perf_event *event, int flags) { struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu); struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; idx = ffz(pmu_cpu->used_mask[0]); if (idx == arc_pmu->n_counters) return -EAGAIN; __set_bit(idx, pmu_cpu->used_mask); hwc->idx = idx; write_aux_reg(ARC_REG_PCT_INDEX, idx); pmu_cpu->act_counter[idx] = event; if (is_sampling_event(event)) { /* Mimic full counter overflow as other arches do */ write_aux_reg(ARC_REG_PCT_INT_CNTL, lower_32_bits(arc_pmu->max_period)); write_aux_reg(ARC_REG_PCT_INT_CNTH, upper_32_bits(arc_pmu->max_period)); } write_aux_reg(ARC_REG_PCT_CONFIG, 0); write_aux_reg(ARC_REG_PCT_COUNTL, 0); write_aux_reg(ARC_REG_PCT_COUNTH, 0); local64_set(&hwc->prev_count, 0); hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED; if (flags & PERF_EF_START) arc_pmu_start(event, PERF_EF_RELOAD); perf_event_update_userpage(event); return 0; } #ifdef CONFIG_ISA_ARCV2 static irqreturn_t arc_pmu_intr(int irq, void *dev) { struct perf_sample_data data; struct arc_pmu_cpu *pmu_cpu = this_cpu_ptr(&arc_pmu_cpu); struct pt_regs *regs; unsigned int active_ints; int idx; arc_pmu_disable(&arc_pmu->pmu); active_ints = read_aux_reg(ARC_REG_PCT_INT_ACT); if (!active_ints) goto done; regs = get_irq_regs(); do { struct perf_event *event; struct hw_perf_event *hwc; idx = __ffs(active_ints); /* Reset interrupt flag by writing of 1 */ write_aux_reg(ARC_REG_PCT_INT_ACT, BIT(idx)); /* * On reset of "interrupt active" bit corresponding * "interrupt enable" bit gets automatically reset as well. * Now we need to re-enable interrupt for the counter. */ write_aux_reg(ARC_REG_PCT_INT_CTRL, read_aux_reg(ARC_REG_PCT_INT_CTRL) | BIT(idx)); event = pmu_cpu->act_counter[idx]; hwc = &event->hw; WARN_ON_ONCE(hwc->idx != idx); arc_perf_event_update(event, &event->hw, event->hw.idx); perf_sample_data_init(&data, 0, hwc->last_period); if (arc_pmu_event_set_period(event)) { if (perf_event_overflow(event, &data, regs)) arc_pmu_stop(event, 0); } active_ints &= ~BIT(idx); } while (active_ints); done: arc_pmu_enable(&arc_pmu->pmu); return IRQ_HANDLED; } #else static irqreturn_t arc_pmu_intr(int irq, void *dev) { return IRQ_NONE; } #endif /* CONFIG_ISA_ARCV2 */ static void arc_cpu_pmu_irq_init(void *data) { int irq = *(int *)data; enable_percpu_irq(irq, IRQ_TYPE_NONE); /* Clear all pending interrupt flags */ write_aux_reg(ARC_REG_PCT_INT_ACT, 0xffffffff); } /* Event field occupies the bottom 15 bits of our config field */ PMU_FORMAT_ATTR(event, "config:0-14"); static struct attribute *arc_pmu_format_attrs[] = { &format_attr_event.attr, NULL, }; static struct attribute_group arc_pmu_format_attr_gr = { .name = "format", .attrs = arc_pmu_format_attrs, }; static ssize_t arc_pmu_events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) { struct perf_pmu_events_attr *pmu_attr; pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr); return sprintf(page, "event=0x%04llx\n", pmu_attr->id); } /* * We don't add attrs here as we don't have pre-defined list of perf events. * We will generate and add attrs dynamically in probe() after we read HW * configuration. */ static struct attribute_group arc_pmu_events_attr_gr = { .name = "events", }; static void arc_pmu_add_raw_event_attr(int j, char *str) { memmove(arc_pmu->raw_entry[j].name, str, ARCPMU_EVENT_NAME_LEN - 1); arc_pmu->attr[j].attr.attr.name = arc_pmu->raw_entry[j].name; arc_pmu->attr[j].attr.attr.mode = VERIFY_OCTAL_PERMISSIONS(0444); arc_pmu->attr[j].attr.show = arc_pmu_events_sysfs_show; arc_pmu->attr[j].id = j; arc_pmu->attrs[j] = &(arc_pmu->attr[j].attr.attr); } static int arc_pmu_raw_alloc(struct device *dev) { arc_pmu->attr = devm_kmalloc_array(dev, arc_pmu->n_events + 1, sizeof(*arc_pmu->attr), GFP_KERNEL | __GFP_ZERO); if (!arc_pmu->attr) return -ENOMEM; arc_pmu->attrs = devm_kmalloc_array(dev, arc_pmu->n_events + 1, sizeof(*arc_pmu->attrs), GFP_KERNEL | __GFP_ZERO); if (!arc_pmu->attrs) return -ENOMEM; arc_pmu->raw_entry = devm_kmalloc_array(dev, arc_pmu->n_events, sizeof(*arc_pmu->raw_entry), GFP_KERNEL | __GFP_ZERO); if (!arc_pmu->raw_entry) return -ENOMEM; return 0; } static inline bool event_in_hw_event_map(int i, char *name) { if (!arc_pmu_ev_hw_map[i]) return false; if (!strlen(arc_pmu_ev_hw_map[i])) return false; if (strcmp(arc_pmu_ev_hw_map[i], name)) return false; return true; } static void arc_pmu_map_hw_event(int j, char *str) { int i; /* See if HW condition has been mapped to a perf event_id */ for (i = 0; i < ARRAY_SIZE(arc_pmu_ev_hw_map); i++) { if (event_in_hw_event_map(i, str)) { pr_debug("mapping perf event %2d to h/w event \'%8s\' (idx %d)\n", i, str, j); arc_pmu->ev_hw_idx[i] = j; } } } static int arc_pmu_device_probe(struct platform_device *pdev) { struct arc_reg_pct_build pct_bcr; struct arc_reg_cc_build cc_bcr; int i, has_interrupts; int counter_size; /* in bits */ union cc_name { struct { u32 word0, word1; char sentinel; } indiv; char str[ARCPMU_EVENT_NAME_LEN]; } cc_name; READ_BCR(ARC_REG_PCT_BUILD, pct_bcr); if (!pct_bcr.v) { pr_err("This core does not have performance counters!\n"); return -ENODEV; } BUILD_BUG_ON(ARC_PERF_MAX_COUNTERS > 32); if (WARN_ON(pct_bcr.c > ARC_PERF_MAX_COUNTERS)) return -EINVAL; READ_BCR(ARC_REG_CC_BUILD, cc_bcr); if (WARN(!cc_bcr.v, "Counters exist but No countable conditions?")) return -EINVAL; arc_pmu = devm_kzalloc(&pdev->dev, sizeof(struct arc_pmu), GFP_KERNEL); if (!arc_pmu) return -ENOMEM; arc_pmu->n_events = cc_bcr.c; if (arc_pmu_raw_alloc(&pdev->dev)) return -ENOMEM; has_interrupts = is_isa_arcv2() ? pct_bcr.i : 0; arc_pmu->n_counters = pct_bcr.c; counter_size = 32 + (pct_bcr.s << 4); arc_pmu->max_period = (1ULL << counter_size) / 2 - 1ULL; pr_info("ARC perf\t: %d counters (%d bits), %d conditions%s\n", arc_pmu->n_counters, counter_size, cc_bcr.c, has_interrupts ? ", [overflow IRQ support]" : ""); cc_name.str[ARCPMU_EVENT_NAME_LEN - 1] = 0; for (i = 0; i < PERF_COUNT_ARC_HW_MAX; i++) arc_pmu->ev_hw_idx[i] = -1; /* loop thru all available h/w condition indexes */ for (i = 0; i < cc_bcr.c; i++) { write_aux_reg(ARC_REG_CC_INDEX, i); cc_name.indiv.word0 = read_aux_reg(ARC_REG_CC_NAME0); cc_name.indiv.word1 = read_aux_reg(ARC_REG_CC_NAME1); arc_pmu_map_hw_event(i, cc_name.str); arc_pmu_add_raw_event_attr(i, cc_name.str); } arc_pmu_events_attr_gr.attrs = arc_pmu->attrs; arc_pmu->attr_groups[ARCPMU_ATTR_GR_EVENTS] = &arc_pmu_events_attr_gr; arc_pmu->attr_groups[ARCPMU_ATTR_GR_FORMATS] = &arc_pmu_format_attr_gr; arc_pmu->pmu = (struct pmu) { .pmu_enable = arc_pmu_enable, .pmu_disable = arc_pmu_disable, .event_init = arc_pmu_event_init, .add = arc_pmu_add, .del = arc_pmu_del, .start = arc_pmu_start, .stop = arc_pmu_stop, .read = arc_pmu_read, .attr_groups = arc_pmu->attr_groups, }; if (has_interrupts) { int irq = platform_get_irq(pdev, 0); if (irq < 0) { pr_err("Cannot get IRQ number for the platform\n"); return -ENODEV; } arc_pmu->irq = irq; /* intc map function ensures irq_set_percpu_devid() called */ request_percpu_irq(irq, arc_pmu_intr, "ARC perf counters", this_cpu_ptr(&arc_pmu_cpu)); on_each_cpu(arc_cpu_pmu_irq_init, &irq, 1); } else arc_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT; /* * perf parser doesn't really like '-' symbol in events name, so let's * use '_' in arc pct name as it goes to kernel PMU event prefix. */ return perf_pmu_register(&arc_pmu->pmu, "arc_pct", PERF_TYPE_RAW); } static const struct of_device_id arc_pmu_match[] = { { .compatible = "snps,arc700-pct" }, { .compatible = "snps,archs-pct" }, {}, }; MODULE_DEVICE_TABLE(of, arc_pmu_match); static struct platform_driver arc_pmu_driver = { .driver = { .name = "arc-pct", .of_match_table = of_match_ptr(arc_pmu_match), }, .probe = arc_pmu_device_probe, }; module_platform_driver(arc_pmu_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Mischa Jonker "); MODULE_DESCRIPTION("ARC PMU driver");