| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Will Deacon | 4720 | 97.44% | 2 | 20.00% |
| Arnd Bergmann | 42 | 0.87% | 1 | 10.00% |
| Jeremy Linton | 41 | 0.85% | 2 | 20.00% |
| Nicholas Mc Guire | 20 | 0.41% | 1 | 10.00% |
| Mathieu J. Poirier | 10 | 0.21% | 1 | 10.00% |
| Suzuki K. Poulose | 5 | 0.10% | 1 | 10.00% |
| Wolfram Sang | 4 | 0.08% | 1 | 10.00% |
| Thomas Gleixner | 2 | 0.04% | 1 | 10.00% |
| Total | 4844 | 10 |
// SPDX-License-Identifier: GPL-2.0-only /* * Perf support for the Statistical Profiling Extension, introduced as * part of ARMv8.2. * * Copyright (C) 2016 ARM Limited * * Author: Will Deacon <will.deacon@arm.com> */ #define PMUNAME "arm_spe" #define DRVNAME PMUNAME "_pmu" #define pr_fmt(fmt) DRVNAME ": " fmt #include <linux/bitops.h> #include <linux/bug.h> #include <linux/capability.h> #include <linux/cpuhotplug.h> #include <linux/cpumask.h> #include <linux/device.h> #include <linux/errno.h> #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/module.h> #include <linux/of_address.h> #include <linux/of_device.h> #include <linux/perf_event.h> #include <linux/perf/arm_pmu.h> #include <linux/platform_device.h> #include <linux/printk.h> #include <linux/slab.h> #include <linux/smp.h> #include <linux/vmalloc.h> #include <asm/barrier.h> #include <asm/cpufeature.h> #include <asm/mmu.h> #include <asm/sysreg.h> #define ARM_SPE_BUF_PAD_BYTE 0 struct arm_spe_pmu_buf { int nr_pages; bool snapshot; void *base; }; struct arm_spe_pmu { struct pmu pmu; struct platform_device *pdev; cpumask_t supported_cpus; struct hlist_node hotplug_node; int irq; /* PPI */ u16 min_period; u16 counter_sz; #define SPE_PMU_FEAT_FILT_EVT (1UL << 0) #define SPE_PMU_FEAT_FILT_TYP (1UL << 1) #define SPE_PMU_FEAT_FILT_LAT (1UL << 2) #define SPE_PMU_FEAT_ARCH_INST (1UL << 3) #define SPE_PMU_FEAT_LDS (1UL << 4) #define SPE_PMU_FEAT_ERND (1UL << 5) #define SPE_PMU_FEAT_DEV_PROBED (1UL << 63) u64 features; u16 max_record_sz; u16 align; struct perf_output_handle __percpu *handle; }; #define to_spe_pmu(p) (container_of(p, struct arm_spe_pmu, pmu)) /* Convert a free-running index from perf into an SPE buffer offset */ #define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT)) /* Keep track of our dynamic hotplug state */ static enum cpuhp_state arm_spe_pmu_online; enum arm_spe_pmu_buf_fault_action { SPE_PMU_BUF_FAULT_ACT_SPURIOUS, SPE_PMU_BUF_FAULT_ACT_FATAL, SPE_PMU_BUF_FAULT_ACT_OK, }; /* This sysfs gunk was really good fun to write. */ enum arm_spe_pmu_capabilities { SPE_PMU_CAP_ARCH_INST = 0, SPE_PMU_CAP_ERND, SPE_PMU_CAP_FEAT_MAX, SPE_PMU_CAP_CNT_SZ = SPE_PMU_CAP_FEAT_MAX, SPE_PMU_CAP_MIN_IVAL, }; static int arm_spe_pmu_feat_caps[SPE_PMU_CAP_FEAT_MAX] = { [SPE_PMU_CAP_ARCH_INST] = SPE_PMU_FEAT_ARCH_INST, [SPE_PMU_CAP_ERND] = SPE_PMU_FEAT_ERND, }; static u32 arm_spe_pmu_cap_get(struct arm_spe_pmu *spe_pmu, int cap) { if (cap < SPE_PMU_CAP_FEAT_MAX) return !!(spe_pmu->features & arm_spe_pmu_feat_caps[cap]); switch (cap) { case SPE_PMU_CAP_CNT_SZ: return spe_pmu->counter_sz; case SPE_PMU_CAP_MIN_IVAL: return spe_pmu->min_period; default: WARN(1, "unknown cap %d\n", cap); } return 0; } static ssize_t arm_spe_pmu_cap_show(struct device *dev, struct device_attribute *attr, char *buf) { struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev); struct dev_ext_attribute *ea = container_of(attr, struct dev_ext_attribute, attr); int cap = (long)ea->var; return snprintf(buf, PAGE_SIZE, "%u\n", arm_spe_pmu_cap_get(spe_pmu, cap)); } #define SPE_EXT_ATTR_ENTRY(_name, _func, _var) \ &((struct dev_ext_attribute[]) { \ { __ATTR(_name, S_IRUGO, _func, NULL), (void *)_var } \ })[0].attr.attr #define SPE_CAP_EXT_ATTR_ENTRY(_name, _var) \ SPE_EXT_ATTR_ENTRY(_name, arm_spe_pmu_cap_show, _var) static struct attribute *arm_spe_pmu_cap_attr[] = { SPE_CAP_EXT_ATTR_ENTRY(arch_inst, SPE_PMU_CAP_ARCH_INST), SPE_CAP_EXT_ATTR_ENTRY(ernd, SPE_PMU_CAP_ERND), SPE_CAP_EXT_ATTR_ENTRY(count_size, SPE_PMU_CAP_CNT_SZ), SPE_CAP_EXT_ATTR_ENTRY(min_interval, SPE_PMU_CAP_MIN_IVAL), NULL, }; static struct attribute_group arm_spe_pmu_cap_group = { .name = "caps", .attrs = arm_spe_pmu_cap_attr, }; /* User ABI */ #define ATTR_CFG_FLD_ts_enable_CFG config /* PMSCR_EL1.TS */ #define ATTR_CFG_FLD_ts_enable_LO 0 #define ATTR_CFG_FLD_ts_enable_HI 0 #define ATTR_CFG_FLD_pa_enable_CFG config /* PMSCR_EL1.PA */ #define ATTR_CFG_FLD_pa_enable_LO 1 #define ATTR_CFG_FLD_pa_enable_HI 1 #define ATTR_CFG_FLD_pct_enable_CFG config /* PMSCR_EL1.PCT */ #define ATTR_CFG_FLD_pct_enable_LO 2 #define ATTR_CFG_FLD_pct_enable_HI 2 #define ATTR_CFG_FLD_jitter_CFG config /* PMSIRR_EL1.RND */ #define ATTR_CFG_FLD_jitter_LO 16 #define ATTR_CFG_FLD_jitter_HI 16 #define ATTR_CFG_FLD_branch_filter_CFG config /* PMSFCR_EL1.B */ #define ATTR_CFG_FLD_branch_filter_LO 32 #define ATTR_CFG_FLD_branch_filter_HI 32 #define ATTR_CFG_FLD_load_filter_CFG config /* PMSFCR_EL1.LD */ #define ATTR_CFG_FLD_load_filter_LO 33 #define ATTR_CFG_FLD_load_filter_HI 33 #define ATTR_CFG_FLD_store_filter_CFG config /* PMSFCR_EL1.ST */ #define ATTR_CFG_FLD_store_filter_LO 34 #define ATTR_CFG_FLD_store_filter_HI 34 #define ATTR_CFG_FLD_event_filter_CFG config1 /* PMSEVFR_EL1 */ #define ATTR_CFG_FLD_event_filter_LO 0 #define ATTR_CFG_FLD_event_filter_HI 63 #define ATTR_CFG_FLD_min_latency_CFG config2 /* PMSLATFR_EL1.MINLAT */ #define ATTR_CFG_FLD_min_latency_LO 0 #define ATTR_CFG_FLD_min_latency_HI 11 /* Why does everything I do descend into this? */ #define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \ (lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi #define _GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \ __GEN_PMU_FORMAT_ATTR(cfg, lo, hi) #define GEN_PMU_FORMAT_ATTR(name) \ PMU_FORMAT_ATTR(name, \ _GEN_PMU_FORMAT_ATTR(ATTR_CFG_FLD_##name##_CFG, \ ATTR_CFG_FLD_##name##_LO, \ ATTR_CFG_FLD_##name##_HI)) #define _ATTR_CFG_GET_FLD(attr, cfg, lo, hi) \ ((((attr)->cfg) >> lo) & GENMASK(hi - lo, 0)) #define ATTR_CFG_GET_FLD(attr, name) \ _ATTR_CFG_GET_FLD(attr, \ ATTR_CFG_FLD_##name##_CFG, \ ATTR_CFG_FLD_##name##_LO, \ ATTR_CFG_FLD_##name##_HI) GEN_PMU_FORMAT_ATTR(ts_enable); GEN_PMU_FORMAT_ATTR(pa_enable); GEN_PMU_FORMAT_ATTR(pct_enable); GEN_PMU_FORMAT_ATTR(jitter); GEN_PMU_FORMAT_ATTR(branch_filter); GEN_PMU_FORMAT_ATTR(load_filter); GEN_PMU_FORMAT_ATTR(store_filter); GEN_PMU_FORMAT_ATTR(event_filter); GEN_PMU_FORMAT_ATTR(min_latency); static struct attribute *arm_spe_pmu_formats_attr[] = { &format_attr_ts_enable.attr, &format_attr_pa_enable.attr, &format_attr_pct_enable.attr, &format_attr_jitter.attr, &format_attr_branch_filter.attr, &format_attr_load_filter.attr, &format_attr_store_filter.attr, &format_attr_event_filter.attr, &format_attr_min_latency.attr, NULL, }; static struct attribute_group arm_spe_pmu_format_group = { .name = "format", .attrs = arm_spe_pmu_formats_attr, }; static ssize_t arm_spe_pmu_get_attr_cpumask(struct device *dev, struct device_attribute *attr, char *buf) { struct arm_spe_pmu *spe_pmu = dev_get_drvdata(dev); return cpumap_print_to_pagebuf(true, buf, &spe_pmu->supported_cpus); } static DEVICE_ATTR(cpumask, S_IRUGO, arm_spe_pmu_get_attr_cpumask, NULL); static struct attribute *arm_spe_pmu_attrs[] = { &dev_attr_cpumask.attr, NULL, }; static struct attribute_group arm_spe_pmu_group = { .attrs = arm_spe_pmu_attrs, }; static const struct attribute_group *arm_spe_pmu_attr_groups[] = { &arm_spe_pmu_group, &arm_spe_pmu_cap_group, &arm_spe_pmu_format_group, NULL, }; /* Convert between user ABI and register values */ static u64 arm_spe_event_to_pmscr(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; u64 reg = 0; reg |= ATTR_CFG_GET_FLD(attr, ts_enable) << SYS_PMSCR_EL1_TS_SHIFT; reg |= ATTR_CFG_GET_FLD(attr, pa_enable) << SYS_PMSCR_EL1_PA_SHIFT; reg |= ATTR_CFG_GET_FLD(attr, pct_enable) << SYS_PMSCR_EL1_PCT_SHIFT; if (!attr->exclude_user) reg |= BIT(SYS_PMSCR_EL1_E0SPE_SHIFT); if (!attr->exclude_kernel) reg |= BIT(SYS_PMSCR_EL1_E1SPE_SHIFT); if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR) && capable(CAP_SYS_ADMIN)) reg |= BIT(SYS_PMSCR_EL1_CX_SHIFT); return reg; } static void arm_spe_event_sanitise_period(struct perf_event *event) { struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu); u64 period = event->hw.sample_period; u64 max_period = SYS_PMSIRR_EL1_INTERVAL_MASK << SYS_PMSIRR_EL1_INTERVAL_SHIFT; if (period < spe_pmu->min_period) period = spe_pmu->min_period; else if (period > max_period) period = max_period; else period &= max_period; event->hw.sample_period = period; } static u64 arm_spe_event_to_pmsirr(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; u64 reg = 0; arm_spe_event_sanitise_period(event); reg |= ATTR_CFG_GET_FLD(attr, jitter) << SYS_PMSIRR_EL1_RND_SHIFT; reg |= event->hw.sample_period; return reg; } static u64 arm_spe_event_to_pmsfcr(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; u64 reg = 0; reg |= ATTR_CFG_GET_FLD(attr, load_filter) << SYS_PMSFCR_EL1_LD_SHIFT; reg |= ATTR_CFG_GET_FLD(attr, store_filter) << SYS_PMSFCR_EL1_ST_SHIFT; reg |= ATTR_CFG_GET_FLD(attr, branch_filter) << SYS_PMSFCR_EL1_B_SHIFT; if (reg) reg |= BIT(SYS_PMSFCR_EL1_FT_SHIFT); if (ATTR_CFG_GET_FLD(attr, event_filter)) reg |= BIT(SYS_PMSFCR_EL1_FE_SHIFT); if (ATTR_CFG_GET_FLD(attr, min_latency)) reg |= BIT(SYS_PMSFCR_EL1_FL_SHIFT); return reg; } static u64 arm_spe_event_to_pmsevfr(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; return ATTR_CFG_GET_FLD(attr, event_filter); } static u64 arm_spe_event_to_pmslatfr(struct perf_event *event) { struct perf_event_attr *attr = &event->attr; return ATTR_CFG_GET_FLD(attr, min_latency) << SYS_PMSLATFR_EL1_MINLAT_SHIFT; } static void arm_spe_pmu_pad_buf(struct perf_output_handle *handle, int len) { struct arm_spe_pmu_buf *buf = perf_get_aux(handle); u64 head = PERF_IDX2OFF(handle->head, buf); memset(buf->base + head, ARM_SPE_BUF_PAD_BYTE, len); if (!buf->snapshot) perf_aux_output_skip(handle, len); } static u64 arm_spe_pmu_next_snapshot_off(struct perf_output_handle *handle) { struct arm_spe_pmu_buf *buf = perf_get_aux(handle); struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu); u64 head = PERF_IDX2OFF(handle->head, buf); u64 limit = buf->nr_pages * PAGE_SIZE; /* * The trace format isn't parseable in reverse, so clamp * the limit to half of the buffer size in snapshot mode * so that the worst case is half a buffer of records, as * opposed to a single record. */ if (head < limit >> 1) limit >>= 1; /* * If we're within max_record_sz of the limit, we must * pad, move the head index and recompute the limit. */ if (limit - head < spe_pmu->max_record_sz) { arm_spe_pmu_pad_buf(handle, limit - head); handle->head = PERF_IDX2OFF(limit, buf); limit = ((buf->nr_pages * PAGE_SIZE) >> 1) + handle->head; } return limit; } static u64 __arm_spe_pmu_next_off(struct perf_output_handle *handle) { struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu); struct arm_spe_pmu_buf *buf = perf_get_aux(handle); const u64 bufsize = buf->nr_pages * PAGE_SIZE; u64 limit = bufsize; u64 head, tail, wakeup; /* * The head can be misaligned for two reasons: * * 1. The hardware left PMBPTR pointing to the first byte after * a record when generating a buffer management event. * * 2. We used perf_aux_output_skip to consume handle->size bytes * and CIRC_SPACE was used to compute the size, which always * leaves one entry free. * * Deal with this by padding to the next alignment boundary and * moving the head index. If we run out of buffer space, we'll * reduce handle->size to zero and end up reporting truncation. */ head = PERF_IDX2OFF(handle->head, buf); if (!IS_ALIGNED(head, spe_pmu->align)) { unsigned long delta = roundup(head, spe_pmu->align) - head; delta = min(delta, handle->size); arm_spe_pmu_pad_buf(handle, delta); head = PERF_IDX2OFF(handle->head, buf); } /* If we've run out of free space, then nothing more to do */ if (!handle->size) goto no_space; /* Compute the tail and wakeup indices now that we've aligned head */ tail = PERF_IDX2OFF(handle->head + handle->size, buf); wakeup = PERF_IDX2OFF(handle->wakeup, buf); /* * Avoid clobbering unconsumed data. We know we have space, so * if we see head == tail we know that the buffer is empty. If * head > tail, then there's nothing to clobber prior to * wrapping. */ if (head < tail) limit = round_down(tail, PAGE_SIZE); /* * Wakeup may be arbitrarily far into the future. If it's not in * the current generation, either we'll wrap before hitting it, * or it's in the past and has been handled already. * * If there's a wakeup before we wrap, arrange to be woken up by * the page boundary following it. Keep the tail boundary if * that's lower. */ if (handle->wakeup < (handle->head + handle->size) && head <= wakeup) limit = min(limit, round_up(wakeup, PAGE_SIZE)); if (limit > head) return limit; arm_spe_pmu_pad_buf(handle, handle->size); no_space: perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED); perf_aux_output_end(handle, 0); return 0; } static u64 arm_spe_pmu_next_off(struct perf_output_handle *handle) { struct arm_spe_pmu_buf *buf = perf_get_aux(handle); struct arm_spe_pmu *spe_pmu = to_spe_pmu(handle->event->pmu); u64 limit = __arm_spe_pmu_next_off(handle); u64 head = PERF_IDX2OFF(handle->head, buf); /* * If the head has come too close to the end of the buffer, * then pad to the end and recompute the limit. */ if (limit && (limit - head < spe_pmu->max_record_sz)) { arm_spe_pmu_pad_buf(handle, limit - head); limit = __arm_spe_pmu_next_off(handle); } return limit; } static void arm_spe_perf_aux_output_begin(struct perf_output_handle *handle, struct perf_event *event) { u64 base, limit; struct arm_spe_pmu_buf *buf; /* Start a new aux session */ buf = perf_aux_output_begin(handle, event); if (!buf) { event->hw.state |= PERF_HES_STOPPED; /* * We still need to clear the limit pointer, since the * profiler might only be disabled by virtue of a fault. */ limit = 0; goto out_write_limit; } limit = buf->snapshot ? arm_spe_pmu_next_snapshot_off(handle) : arm_spe_pmu_next_off(handle); if (limit) limit |= BIT(SYS_PMBLIMITR_EL1_E_SHIFT); limit += (u64)buf->base; base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf); write_sysreg_s(base, SYS_PMBPTR_EL1); out_write_limit: write_sysreg_s(limit, SYS_PMBLIMITR_EL1); } static void arm_spe_perf_aux_output_end(struct perf_output_handle *handle) { struct arm_spe_pmu_buf *buf = perf_get_aux(handle); u64 offset, size; offset = read_sysreg_s(SYS_PMBPTR_EL1) - (u64)buf->base; size = offset - PERF_IDX2OFF(handle->head, buf); if (buf->snapshot) handle->head = offset; perf_aux_output_end(handle, size); } static void arm_spe_pmu_disable_and_drain_local(void) { /* Disable profiling at EL0 and EL1 */ write_sysreg_s(0, SYS_PMSCR_EL1); isb(); /* Drain any buffered data */ psb_csync(); dsb(nsh); /* Disable the profiling buffer */ write_sysreg_s(0, SYS_PMBLIMITR_EL1); isb(); } /* IRQ handling */ static enum arm_spe_pmu_buf_fault_action arm_spe_pmu_buf_get_fault_act(struct perf_output_handle *handle) { const char *err_str; u64 pmbsr; enum arm_spe_pmu_buf_fault_action ret; /* * Ensure new profiling data is visible to the CPU and any external * aborts have been resolved. */ psb_csync(); dsb(nsh); /* Ensure hardware updates to PMBPTR_EL1 are visible */ isb(); /* Service required? */ pmbsr = read_sysreg_s(SYS_PMBSR_EL1); if (!(pmbsr & BIT(SYS_PMBSR_EL1_S_SHIFT))) return SPE_PMU_BUF_FAULT_ACT_SPURIOUS; /* * If we've lost data, disable profiling and also set the PARTIAL * flag to indicate that the last record is corrupted. */ if (pmbsr & BIT(SYS_PMBSR_EL1_DL_SHIFT)) perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED | PERF_AUX_FLAG_PARTIAL); /* Report collisions to userspace so that it can up the period */ if (pmbsr & BIT(SYS_PMBSR_EL1_COLL_SHIFT)) perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION); /* We only expect buffer management events */ switch (pmbsr & (SYS_PMBSR_EL1_EC_MASK << SYS_PMBSR_EL1_EC_SHIFT)) { case SYS_PMBSR_EL1_EC_BUF: /* Handled below */ break; case SYS_PMBSR_EL1_EC_FAULT_S1: case SYS_PMBSR_EL1_EC_FAULT_S2: err_str = "Unexpected buffer fault"; goto out_err; default: err_str = "Unknown error code"; goto out_err; } /* Buffer management event */ switch (pmbsr & (SYS_PMBSR_EL1_BUF_BSC_MASK << SYS_PMBSR_EL1_BUF_BSC_SHIFT)) { case SYS_PMBSR_EL1_BUF_BSC_FULL: ret = SPE_PMU_BUF_FAULT_ACT_OK; goto out_stop; default: err_str = "Unknown buffer status code"; } out_err: pr_err_ratelimited("%s on CPU %d [PMBSR=0x%016llx, PMBPTR=0x%016llx, PMBLIMITR=0x%016llx]\n", err_str, smp_processor_id(), pmbsr, read_sysreg_s(SYS_PMBPTR_EL1), read_sysreg_s(SYS_PMBLIMITR_EL1)); ret = SPE_PMU_BUF_FAULT_ACT_FATAL; out_stop: arm_spe_perf_aux_output_end(handle); return ret; } static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev) { struct perf_output_handle *handle = dev; struct perf_event *event = handle->event; enum arm_spe_pmu_buf_fault_action act; if (!perf_get_aux(handle)) return IRQ_NONE; act = arm_spe_pmu_buf_get_fault_act(handle); if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS) return IRQ_NONE; /* * Ensure perf callbacks have completed, which may disable the * profiling buffer in response to a TRUNCATION flag. */ irq_work_run(); switch (act) { case SPE_PMU_BUF_FAULT_ACT_FATAL: /* * If a fatal exception occurred then leaving the profiling * buffer enabled is a recipe waiting to happen. Since * fatal faults don't always imply truncation, make sure * that the profiling buffer is disabled explicitly before * clearing the syndrome register. */ arm_spe_pmu_disable_and_drain_local(); break; case SPE_PMU_BUF_FAULT_ACT_OK: /* * We handled the fault (the buffer was full), so resume * profiling as long as we didn't detect truncation. * PMBPTR might be misaligned, but we'll burn that bridge * when we get to it. */ if (!(handle->aux_flags & PERF_AUX_FLAG_TRUNCATED)) { arm_spe_perf_aux_output_begin(handle, event); isb(); } break; case SPE_PMU_BUF_FAULT_ACT_SPURIOUS: /* We've seen you before, but GCC has the memory of a sieve. */ break; } /* The buffer pointers are now sane, so resume profiling. */ write_sysreg_s(0, SYS_PMBSR_EL1); return IRQ_HANDLED; } /* Perf callbacks */ static int arm_spe_pmu_event_init(struct perf_event *event) { u64 reg; struct perf_event_attr *attr = &event->attr; struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu); /* This is, of course, deeply driver-specific */ if (attr->type != event->pmu->type) return -ENOENT; if (event->cpu >= 0 && !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus)) return -ENOENT; if (arm_spe_event_to_pmsevfr(event) & SYS_PMSEVFR_EL1_RES0) return -EOPNOTSUPP; if (attr->exclude_idle) return -EOPNOTSUPP; /* * Feedback-directed frequency throttling doesn't work when we * have a buffer of samples. We'd need to manually count the * samples in the buffer when it fills up and adjust the event * count to reflect that. Instead, just force the user to specify * a sample period. */ if (attr->freq) return -EINVAL; reg = arm_spe_event_to_pmsfcr(event); if ((reg & BIT(SYS_PMSFCR_EL1_FE_SHIFT)) && !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT)) return -EOPNOTSUPP; if ((reg & BIT(SYS_PMSFCR_EL1_FT_SHIFT)) && !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP)) return -EOPNOTSUPP; if ((reg & BIT(SYS_PMSFCR_EL1_FL_SHIFT)) && !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT)) return -EOPNOTSUPP; reg = arm_spe_event_to_pmscr(event); if (!capable(CAP_SYS_ADMIN) && (reg & (BIT(SYS_PMSCR_EL1_PA_SHIFT) | BIT(SYS_PMSCR_EL1_CX_SHIFT) | BIT(SYS_PMSCR_EL1_PCT_SHIFT)))) return -EACCES; return 0; } static void arm_spe_pmu_start(struct perf_event *event, int flags) { u64 reg; struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle); hwc->state = 0; arm_spe_perf_aux_output_begin(handle, event); if (hwc->state) return; reg = arm_spe_event_to_pmsfcr(event); write_sysreg_s(reg, SYS_PMSFCR_EL1); reg = arm_spe_event_to_pmsevfr(event); write_sysreg_s(reg, SYS_PMSEVFR_EL1); reg = arm_spe_event_to_pmslatfr(event); write_sysreg_s(reg, SYS_PMSLATFR_EL1); if (flags & PERF_EF_RELOAD) { reg = arm_spe_event_to_pmsirr(event); write_sysreg_s(reg, SYS_PMSIRR_EL1); isb(); reg = local64_read(&hwc->period_left); write_sysreg_s(reg, SYS_PMSICR_EL1); } reg = arm_spe_event_to_pmscr(event); isb(); write_sysreg_s(reg, SYS_PMSCR_EL1); } static void arm_spe_pmu_stop(struct perf_event *event, int flags) { struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; struct perf_output_handle *handle = this_cpu_ptr(spe_pmu->handle); /* If we're already stopped, then nothing to do */ if (hwc->state & PERF_HES_STOPPED) return; /* Stop all trace generation */ arm_spe_pmu_disable_and_drain_local(); if (flags & PERF_EF_UPDATE) { /* * If there's a fault pending then ensure we contain it * to this buffer, since we might be on the context-switch * path. */ if (perf_get_aux(handle)) { enum arm_spe_pmu_buf_fault_action act; act = arm_spe_pmu_buf_get_fault_act(handle); if (act == SPE_PMU_BUF_FAULT_ACT_SPURIOUS) arm_spe_perf_aux_output_end(handle); else write_sysreg_s(0, SYS_PMBSR_EL1); } /* * This may also contain ECOUNT, but nobody else should * be looking at period_left, since we forbid frequency * based sampling. */ local64_set(&hwc->period_left, read_sysreg_s(SYS_PMSICR_EL1)); hwc->state |= PERF_HES_UPTODATE; } hwc->state |= PERF_HES_STOPPED; } static int arm_spe_pmu_add(struct perf_event *event, int flags) { int ret = 0; struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu); struct hw_perf_event *hwc = &event->hw; int cpu = event->cpu == -1 ? smp_processor_id() : event->cpu; if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus)) return -ENOENT; hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED; if (flags & PERF_EF_START) { arm_spe_pmu_start(event, PERF_EF_RELOAD); if (hwc->state & PERF_HES_STOPPED) ret = -EINVAL; } return ret; } static void arm_spe_pmu_del(struct perf_event *event, int flags) { arm_spe_pmu_stop(event, PERF_EF_UPDATE); } static void arm_spe_pmu_read(struct perf_event *event) { } static void *arm_spe_pmu_setup_aux(struct perf_event *event, void **pages, int nr_pages, bool snapshot) { int i, cpu = event->cpu; struct page **pglist; struct arm_spe_pmu_buf *buf; /* We need at least two pages for this to work. */ if (nr_pages < 2) return NULL; /* * We require an even number of pages for snapshot mode, so that * we can effectively treat the buffer as consisting of two equal * parts and give userspace a fighting chance of getting some * useful data out of it. */ if (!nr_pages || (snapshot && (nr_pages & 1))) return NULL; if (cpu == -1) cpu = raw_smp_processor_id(); buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, cpu_to_node(cpu)); if (!buf) return NULL; pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL); if (!pglist) goto out_free_buf; for (i = 0; i < nr_pages; ++i) pglist[i] = virt_to_page(pages[i]); buf->base = vmap(pglist, nr_pages, VM_MAP, PAGE_KERNEL); if (!buf->base) goto out_free_pglist; buf->nr_pages = nr_pages; buf->snapshot = snapshot; kfree(pglist); return buf; out_free_pglist: kfree(pglist); out_free_buf: kfree(buf); return NULL; } static void arm_spe_pmu_free_aux(void *aux) { struct arm_spe_pmu_buf *buf = aux; vunmap(buf->base); kfree(buf); } /* Initialisation and teardown functions */ static int arm_spe_pmu_perf_init(struct arm_spe_pmu *spe_pmu) { static atomic_t pmu_idx = ATOMIC_INIT(-1); int idx; char *name; struct device *dev = &spe_pmu->pdev->dev; spe_pmu->pmu = (struct pmu) { .module = THIS_MODULE, .capabilities = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE, .attr_groups = arm_spe_pmu_attr_groups, /* * We hitch a ride on the software context here, so that * we can support per-task profiling (which is not possible * with the invalid context as it doesn't get sched callbacks). * This requires that userspace either uses a dummy event for * perf_event_open, since the aux buffer is not setup until * a subsequent mmap, or creates the profiling event in a * disabled state and explicitly PERF_EVENT_IOC_ENABLEs it * once the buffer has been created. */ .task_ctx_nr = perf_sw_context, .event_init = arm_spe_pmu_event_init, .add = arm_spe_pmu_add, .del = arm_spe_pmu_del, .start = arm_spe_pmu_start, .stop = arm_spe_pmu_stop, .read = arm_spe_pmu_read, .setup_aux = arm_spe_pmu_setup_aux, .free_aux = arm_spe_pmu_free_aux, }; idx = atomic_inc_return(&pmu_idx); name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME, idx); if (!name) { dev_err(dev, "failed to allocate name for pmu %d\n", idx); return -ENOMEM; } return perf_pmu_register(&spe_pmu->pmu, name, -1); } static void arm_spe_pmu_perf_destroy(struct arm_spe_pmu *spe_pmu) { perf_pmu_unregister(&spe_pmu->pmu); } static void __arm_spe_pmu_dev_probe(void *info) { int fld; u64 reg; struct arm_spe_pmu *spe_pmu = info; struct device *dev = &spe_pmu->pdev->dev; fld = cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64DFR0_EL1), ID_AA64DFR0_PMSVER_SHIFT); if (!fld) { dev_err(dev, "unsupported ID_AA64DFR0_EL1.PMSVer [%d] on CPU %d\n", fld, smp_processor_id()); return; } /* Read PMBIDR first to determine whether or not we have access */ reg = read_sysreg_s(SYS_PMBIDR_EL1); if (reg & BIT(SYS_PMBIDR_EL1_P_SHIFT)) { dev_err(dev, "profiling buffer owned by higher exception level\n"); return; } /* Minimum alignment. If it's out-of-range, then fail the probe */ fld = reg >> SYS_PMBIDR_EL1_ALIGN_SHIFT & SYS_PMBIDR_EL1_ALIGN_MASK; spe_pmu->align = 1 << fld; if (spe_pmu->align > SZ_2K) { dev_err(dev, "unsupported PMBIDR.Align [%d] on CPU %d\n", fld, smp_processor_id()); return; } /* It's now safe to read PMSIDR and figure out what we've got */ reg = read_sysreg_s(SYS_PMSIDR_EL1); if (reg & BIT(SYS_PMSIDR_EL1_FE_SHIFT)) spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT; if (reg & BIT(SYS_PMSIDR_EL1_FT_SHIFT)) spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP; if (reg & BIT(SYS_PMSIDR_EL1_FL_SHIFT)) spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT; if (reg & BIT(SYS_PMSIDR_EL1_ARCHINST_SHIFT)) spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST; if (reg & BIT(SYS_PMSIDR_EL1_LDS_SHIFT)) spe_pmu->features |= SPE_PMU_FEAT_LDS; if (reg & BIT(SYS_PMSIDR_EL1_ERND_SHIFT)) spe_pmu->features |= SPE_PMU_FEAT_ERND; /* This field has a spaced out encoding, so just use a look-up */ fld = reg >> SYS_PMSIDR_EL1_INTERVAL_SHIFT & SYS_PMSIDR_EL1_INTERVAL_MASK; switch (fld) { case 0: spe_pmu->min_period = 256; break; case 2: spe_pmu->min_period = 512; break; case 3: spe_pmu->min_period = 768; break; case 4: spe_pmu->min_period = 1024; break; case 5: spe_pmu->min_period = 1536; break; case 6: spe_pmu->min_period = 2048; break; case 7: spe_pmu->min_period = 3072; break; default: dev_warn(dev, "unknown PMSIDR_EL1.Interval [%d]; assuming 8\n", fld); /* Fallthrough */ case 8: spe_pmu->min_period = 4096; } /* Maximum record size. If it's out-of-range, then fail the probe */ fld = reg >> SYS_PMSIDR_EL1_MAXSIZE_SHIFT & SYS_PMSIDR_EL1_MAXSIZE_MASK; spe_pmu->max_record_sz = 1 << fld; if (spe_pmu->max_record_sz > SZ_2K || spe_pmu->max_record_sz < 16) { dev_err(dev, "unsupported PMSIDR_EL1.MaxSize [%d] on CPU %d\n", fld, smp_processor_id()); return; } fld = reg >> SYS_PMSIDR_EL1_COUNTSIZE_SHIFT & SYS_PMSIDR_EL1_COUNTSIZE_MASK; switch (fld) { default: dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n", fld); /* Fallthrough */ case 2: spe_pmu->counter_sz = 12; } dev_info(dev, "probed for CPUs %*pbl [max_record_sz %u, align %u, features 0x%llx]\n", cpumask_pr_args(&spe_pmu->supported_cpus), spe_pmu->max_record_sz, spe_pmu->align, spe_pmu->features); spe_pmu->features |= SPE_PMU_FEAT_DEV_PROBED; return; } static void __arm_spe_pmu_reset_local(void) { /* * This is probably overkill, as we have no idea where we're * draining any buffered data to... */ arm_spe_pmu_disable_and_drain_local(); /* Reset the buffer base pointer */ write_sysreg_s(0, SYS_PMBPTR_EL1); isb(); /* Clear any pending management interrupts */ write_sysreg_s(0, SYS_PMBSR_EL1); isb(); } static void __arm_spe_pmu_setup_one(void *info) { struct arm_spe_pmu *spe_pmu = info; __arm_spe_pmu_reset_local(); enable_percpu_irq(spe_pmu->irq, IRQ_TYPE_NONE); } static void __arm_spe_pmu_stop_one(void *info) { struct arm_spe_pmu *spe_pmu = info; disable_percpu_irq(spe_pmu->irq); __arm_spe_pmu_reset_local(); } static int arm_spe_pmu_cpu_startup(unsigned int cpu, struct hlist_node *node) { struct arm_spe_pmu *spe_pmu; spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node); if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus)) return 0; __arm_spe_pmu_setup_one(spe_pmu); return 0; } static int arm_spe_pmu_cpu_teardown(unsigned int cpu, struct hlist_node *node) { struct arm_spe_pmu *spe_pmu; spe_pmu = hlist_entry_safe(node, struct arm_spe_pmu, hotplug_node); if (!cpumask_test_cpu(cpu, &spe_pmu->supported_cpus)) return 0; __arm_spe_pmu_stop_one(spe_pmu); return 0; } static int arm_spe_pmu_dev_init(struct arm_spe_pmu *spe_pmu) { int ret; cpumask_t *mask = &spe_pmu->supported_cpus; /* Make sure we probe the hardware on a relevant CPU */ ret = smp_call_function_any(mask, __arm_spe_pmu_dev_probe, spe_pmu, 1); if (ret || !(spe_pmu->features & SPE_PMU_FEAT_DEV_PROBED)) return -ENXIO; /* Request our PPIs (note that the IRQ is still disabled) */ ret = request_percpu_irq(spe_pmu->irq, arm_spe_pmu_irq_handler, DRVNAME, spe_pmu->handle); if (ret) return ret; /* * Register our hotplug notifier now so we don't miss any events. * This will enable the IRQ for any supported CPUs that are already * up. */ ret = cpuhp_state_add_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node); if (ret) free_percpu_irq(spe_pmu->irq, spe_pmu->handle); return ret; } static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu) { cpuhp_state_remove_instance(arm_spe_pmu_online, &spe_pmu->hotplug_node); free_percpu_irq(spe_pmu->irq, spe_pmu->handle); } /* Driver and device probing */ static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu) { struct platform_device *pdev = spe_pmu->pdev; int irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "failed to get IRQ (%d)\n", irq); return -ENXIO; } if (!irq_is_percpu(irq)) { dev_err(&pdev->dev, "expected PPI but got SPI (%d)\n", irq); return -EINVAL; } if (irq_get_percpu_devid_partition(irq, &spe_pmu->supported_cpus)) { dev_err(&pdev->dev, "failed to get PPI partition (%d)\n", irq); return -EINVAL; } spe_pmu->irq = irq; return 0; } static const struct of_device_id arm_spe_pmu_of_match[] = { { .compatible = "arm,statistical-profiling-extension-v1", .data = (void *)1 }, { /* Sentinel */ }, }; MODULE_DEVICE_TABLE(of, arm_spe_pmu_of_match); static const struct platform_device_id arm_spe_match[] = { { ARMV8_SPE_PDEV_NAME, 0}, { } }; MODULE_DEVICE_TABLE(platform, arm_spe_match); static int arm_spe_pmu_device_probe(struct platform_device *pdev) { int ret; struct arm_spe_pmu *spe_pmu; struct device *dev = &pdev->dev; /* * If kernelspace is unmapped when running at EL0, then the SPE * buffer will fault and prematurely terminate the AUX session. */ if (arm64_kernel_unmapped_at_el0()) { dev_warn_once(dev, "profiling buffer inaccessible. Try passing \"kpti=off\" on the kernel command line\n"); return -EPERM; } spe_pmu = devm_kzalloc(dev, sizeof(*spe_pmu), GFP_KERNEL); if (!spe_pmu) { dev_err(dev, "failed to allocate spe_pmu\n"); return -ENOMEM; } spe_pmu->handle = alloc_percpu(typeof(*spe_pmu->handle)); if (!spe_pmu->handle) return -ENOMEM; spe_pmu->pdev = pdev; platform_set_drvdata(pdev, spe_pmu); ret = arm_spe_pmu_irq_probe(spe_pmu); if (ret) goto out_free_handle; ret = arm_spe_pmu_dev_init(spe_pmu); if (ret) goto out_free_handle; ret = arm_spe_pmu_perf_init(spe_pmu); if (ret) goto out_teardown_dev; return 0; out_teardown_dev: arm_spe_pmu_dev_teardown(spe_pmu); out_free_handle: free_percpu(spe_pmu->handle); return ret; } static int arm_spe_pmu_device_remove(struct platform_device *pdev) { struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev); arm_spe_pmu_perf_destroy(spe_pmu); arm_spe_pmu_dev_teardown(spe_pmu); free_percpu(spe_pmu->handle); return 0; } static struct platform_driver arm_spe_pmu_driver = { .id_table = arm_spe_match, .driver = { .name = DRVNAME, .of_match_table = of_match_ptr(arm_spe_pmu_of_match), }, .probe = arm_spe_pmu_device_probe, .remove = arm_spe_pmu_device_remove, }; static int __init arm_spe_pmu_init(void) { int ret; ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME, arm_spe_pmu_cpu_startup, arm_spe_pmu_cpu_teardown); if (ret < 0) return ret; arm_spe_pmu_online = ret; ret = platform_driver_register(&arm_spe_pmu_driver); if (ret) cpuhp_remove_multi_state(arm_spe_pmu_online); return ret; } static void __exit arm_spe_pmu_exit(void) { platform_driver_unregister(&arm_spe_pmu_driver); cpuhp_remove_multi_state(arm_spe_pmu_online); } module_init(arm_spe_pmu_init); module_exit(arm_spe_pmu_exit); MODULE_DESCRIPTION("Perf driver for the ARMv8.2 Statistical Profiling Extension"); MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>"); MODULE_LICENSE("GPL v2");
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