diff options
Diffstat (limited to 'drivers/perf/arm_spe_pmu.c')
| -rw-r--r-- | drivers/perf/arm_spe_pmu.c | 1249 |
1 files changed, 1249 insertions, 0 deletions
diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c new file mode 100644 index 000000000000..8ce262fc2561 --- /dev/null +++ b/drivers/perf/arm_spe_pmu.c @@ -0,0 +1,1249 @@ +/* + * Perf support for the Statistical Profiling Extension, introduced as + * part of ARMv8.2. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * 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/cpuhotplug.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/of_device.h> +#include <linux/perf_event.h> +#include <linux/platform_device.h> +#include <linux/slab.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 platform_device *pdev = to_platform_device(dev); + struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev); + 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 platform_device *pdev = to_platform_device(dev); + struct arm_spe_pmu *spe_pmu = platform_get_drvdata(pdev); + + 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(int cpu, void **pages, int nr_pages, + bool snapshot) +{ + int i; + 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) { + struct page *page = virt_to_page(pages[i]); + + if (PagePrivate(page)) { + pr_warn("unexpected high-order page for auxbuf!"); + goto out_free_pglist; + } + + 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); + 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 */ }, +}; + +static int arm_spe_pmu_device_dt_probe(struct platform_device *pdev) +{ + int ret; + struct arm_spe_pmu *spe_pmu; + struct device *dev = &pdev->dev; + + 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 = { + .driver = { + .name = DRVNAME, + .of_match_table = of_match_ptr(arm_spe_pmu_of_match), + }, + .probe = arm_spe_pmu_device_dt_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"); |