The ARMv8.2 architecture introduces the Statistical Profiling Extension (SPE). SPE provides a way to configure and collect profiling samples from the CPU in the form of a trace buffer, which can be mapped directly into userspace using the perf AUX buffer infrastructure.
This patch adds support for SPE in the form of a new perf driver. Cc: Mark Rutland <[email protected]> Cc: Alexander Shishkin <[email protected]> Signed-off-by: Will Deacon <[email protected]> --- drivers/perf/Kconfig | 8 + drivers/perf/Makefile | 1 + drivers/perf/arm_spe_pmu.c | 1247 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 1256 insertions(+) create mode 100644 drivers/perf/arm_spe_pmu.c diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig index 4d5c5f9f0dbd..32b9d2756b0e 100644 --- a/drivers/perf/Kconfig +++ b/drivers/perf/Kconfig @@ -19,4 +19,12 @@ config XGENE_PMU help Say y if you want to use APM X-Gene SoC performance monitors. +config ARM_SPE_PMU + tristate "Enable support for the ARMv8.2 Statistical Profiling Extension" + depends on PERF_EVENTS && ARM64 + help + Enable perf support for the ARMv8.2 Statistical Profiling + Extension, which provides periodic sampling of operations in + the CPU pipeline and reports this via the perf AUX interface. + endmenu diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile index b116e982810b..3a324da7d360 100644 --- a/drivers/perf/Makefile +++ b/drivers/perf/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_ARM_PMU) += arm_pmu.o obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o +obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c new file mode 100644 index 000000000000..88ac10aa24ac --- /dev/null +++ b/drivers/perf/arm_spe_pmu.c @@ -0,0 +1,1247 @@ +/* + * 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 <[email protected]> + */ + +#define DRVNAME "arm_spe_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> + +/* ID registers */ +#define PMSIDR_EL1 sys_reg(3, 0, 9, 9, 7) +#define PMSIDR_EL1_FE_SHIFT 0 +#define PMSIDR_EL1_FT_SHIFT 1 +#define PMSIDR_EL1_FL_SHIFT 2 +#define PMSIDR_EL1_ARCHINST_SHIFT 3 +#define PMSIDR_EL1_LDS_SHIFT 4 +#define PMSIDR_EL1_ERND_SHIFT 5 +#define PMSIDR_EL1_INTERVAL_SHIFT 8 +#define PMSIDR_EL1_INTERVAL_MASK 0xfUL +#define PMSIDR_EL1_MAXSIZE_SHIFT 12 +#define PMSIDR_EL1_MAXSIZE_MASK 0xfUL +#define PMSIDR_EL1_COUNTSIZE_SHIFT 16 +#define PMSIDR_EL1_COUNTSIZE_MASK 0xfUL + +#define PMBIDR_EL1 sys_reg(3, 0, 9, 10, 7) +#define PMBIDR_EL1_ALIGN_SHIFT 0 +#define PMBIDR_EL1_ALIGN_MASK 0xfU +#define PMBIDR_EL1_P_SHIFT 4 +#define PMBIDR_EL1_F_SHIFT 5 + +/* Sampling controls */ +#define PMSCR_EL1 sys_reg(3, 0, 9, 9, 0) +#define PMSCR_EL1_E0SPE_SHIFT 0 +#define PMSCR_EL1_E1SPE_SHIFT 1 +#define PMSCR_EL1_CX_SHIFT 3 +#define PMSCR_EL1_PA_SHIFT 4 +#define PMSCR_EL1_TS_SHIFT 5 +#define PMSCR_EL1_PCT_SHIFT 6 + +#define PMSICR_EL1 sys_reg(3, 0, 9, 9, 2) + +#define PMSIRR_EL1 sys_reg(3, 0, 9, 9, 3) +#define PMSIRR_EL1_RND_SHIFT 0 +#define PMSIRR_EL1_IVAL_MASK 0xffUL + +/* Filtering controls */ +#define PMSFCR_EL1 sys_reg(3, 0, 9, 9, 4) +#define PMSFCR_EL1_FE_SHIFT 0 +#define PMSFCR_EL1_FT_SHIFT 1 +#define PMSFCR_EL1_FL_SHIFT 2 +#define PMSFCR_EL1_B_SHIFT 16 +#define PMSFCR_EL1_LD_SHIFT 17 +#define PMSFCR_EL1_ST_SHIFT 18 + +#define PMSEVFR_EL1 sys_reg(3, 0, 9, 9, 5) +#define PMSEVFR_EL1_RES0 0x0000ffff00ff0f55UL + +#define PMSLATFR_EL1 sys_reg(3, 0, 9, 9, 6) +#define PMSLATFR_EL1_MINLAT_SHIFT 0 + +/* Buffer controls */ +#define PMBLIMITR_EL1 sys_reg(3, 0, 9, 10, 0) +#define PMBLIMITR_EL1_E_SHIFT 0 +#define PMBLIMITR_EL1_FM_SHIFT 1 +#define PMBLIMITR_EL1_FM_MASK 0x3UL +#define PMBLIMITR_EL1_FM_STOP_IRQ (0 << PMBLIMITR_EL1_FM_SHIFT) + +#define PMBPTR_EL1 sys_reg(3, 0, 9, 10, 1) + +/* Buffer error reporting */ +#define PMBSR_EL1 sys_reg(3, 0, 9, 10, 3) +#define PMBSR_EL1_COLL_SHIFT 16 +#define PMBSR_EL1_S_SHIFT 17 +#define PMBSR_EL1_EA_SHIFT 18 +#define PMBSR_EL1_DL_SHIFT 19 +#define PMBSR_EL1_EC_SHIFT 26 +#define PMBSR_EL1_EC_MASK 0x3fUL + +#define PMBSR_EL1_EC_BUF (0x0UL << PMBSR_EL1_EC_SHIFT) +#define PMBSR_EL1_EC_FAULT_S1 (0x24UL << PMBSR_EL1_EC_SHIFT) +#define PMBSR_EL1_EC_FAULT_S2 (0x25UL << PMBSR_EL1_EC_SHIFT) + +#define PMBSR_EL1_FAULT_FSC_SHIFT 0 +#define PMBSR_EL1_FAULT_FSC_MASK 0x3fUL + +#define PMBSR_EL1_BUF_BSC_SHIFT 0 +#define PMBSR_EL1_BUF_BSC_MASK 0x3fUL + +#define PMBSR_EL1_BUF_BSC_FULL (0x1UL << PMBSR_EL1_BUF_BSC_SHIFT) + +#define psb_csync() asm volatile("hint #17") + +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 cnt_width; + +#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) - 1)) + +/* Convert a limit register into an SPE buffer offset */ +#define PMBLIMITR2OFF(lim, buf) (((lim) & PAGE_MASK) - (u64)((buf)->base)) + +/* Keep track of our dynamic hotplug state */ +static enum cpuhp_state arm_spe_pmu_online; + +/* 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->cnt_width; + 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_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(jitter); +GEN_PMU_FORMAT_ATTR(load_filter); +GEN_PMU_FORMAT_ATTR(store_filter); +GEN_PMU_FORMAT_ATTR(branch_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_jitter.attr, + &format_attr_load_filter.attr, + &format_attr_store_filter.attr, + &format_attr_branch_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) << PMSCR_EL1_TS_SHIFT; + reg |= ATTR_CFG_GET_FLD(attr, pa_enable) << PMSCR_EL1_PA_SHIFT; + + if (!attr->exclude_user) + reg |= BIT(PMSCR_EL1_E0SPE_SHIFT); + + if (!attr->exclude_kernel) + reg |= BIT(PMSCR_EL1_E1SPE_SHIFT); + + if (IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR)) + reg |= BIT(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 & ~PMSIRR_EL1_IVAL_MASK; + + if (period < spe_pmu->min_period) + period = spe_pmu->min_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) << 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) << PMSFCR_EL1_LD_SHIFT; + reg |= ATTR_CFG_GET_FLD(attr, store_filter) << PMSFCR_EL1_ST_SHIFT; + reg |= ATTR_CFG_GET_FLD(attr, branch_filter) << PMSFCR_EL1_B_SHIFT; + + if (reg) + reg |= BIT(PMSFCR_EL1_FT_SHIFT); + + if (ATTR_CFG_GET_FLD(attr, event_filter)) + reg |= BIT(PMSFCR_EL1_FE_SHIFT); + + if (ATTR_CFG_GET_FLD(attr, min_latency)) + reg |= BIT(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) << PMSLATFR_EL1_MINLAT_SHIFT; +} + +static bool arm_spe_pmu_buffer_mgmt_pending(u64 pmbsr) +{ + const char *err_str; + + /* Service required? */ + if (!(pmbsr & BIT(PMBSR_EL1_S_SHIFT))) + return false; + + /* We only expect buffer management events */ + switch (pmbsr & (PMBSR_EL1_EC_MASK << PMBSR_EL1_EC_SHIFT)) { + case PMBSR_EL1_EC_BUF: + /* Handled below */ + break; + case PMBSR_EL1_EC_FAULT_S1: + case 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 & (PMBSR_EL1_BUF_BSC_MASK << PMBSR_EL1_BUF_BSC_SHIFT)) { + case PMBSR_EL1_BUF_BSC_FULL: + return true; + default: + err_str = "Unknown buffer status code"; + } + +out_err: + pr_err_ratelimited("%s on CPU %d [PMBSR=0x%08llx]\n", err_str, + smp_processor_id(), pmbsr); + return false; +} + +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) { + memset(buf->base + head, 0, 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_buf *buf = perf_get_aux(handle); + u64 head = PERF_IDX2OFF(handle->head, buf); + u64 tail = PERF_IDX2OFF(handle->head + handle->size, buf); + u64 wakeup = PERF_IDX2OFF(handle->wakeup, buf); + u64 limit = buf->nr_pages * PAGE_SIZE; + + /* + * Set the limit pointer to either the watermark or the + * current tail pointer; whichever comes first. + */ + if (handle->head + handle->size <= handle->wakeup) { + /* The tail is next, so check for wrapping */ + if (tail >= head) { + /* + * No wrapping, but need to align downwards to + * avoid corrupting unconsumed data. + */ + limit = round_down(tail, PAGE_SIZE); + + } + } else if (wakeup >= head) { + /* + * The wakeup is next and doesn't wrap. Align upwards to + * ensure that we do indeed reach the watermark. + */ + limit = round_up(wakeup, PAGE_SIZE); + + /* + * If rounding up crosses the tail, then we have to + * round down to avoid corrupting unconsumed data. + * Hopefully the tail will have moved by the time we + * hit the new limit. + */ + if (wakeup < tail && limit > tail) + limit = round_down(wakeup, PAGE_SIZE); + } + + /* + * If rounding down crosses the head, then the buffer is full, + * so pad to tail and end the session. + */ + if (limit <= head) { + memset(buf->base + head, 0, handle->size); + perf_aux_output_skip(handle, handle->size); + perf_aux_output_end(handle, 0, PERF_AUX_FLAG_TRUNCATED); + limit = 0; + } + + return limit; +} + +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)) { + memset(buf->base + head, 0, limit - head); + perf_aux_output_skip(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(PMBLIMITR_EL1_E_SHIFT); + + base = (u64)buf->base + PERF_IDX2OFF(handle->head, buf); + write_sysreg_s(base, PMBPTR_EL1); + limit += (u64)buf->base; + +out_write_limit: + write_sysreg_s(limit, PMBLIMITR_EL1); +} + +static bool arm_spe_perf_aux_output_end(struct perf_output_handle *handle, + struct perf_event *event, + bool resume) +{ + u64 pmbptr, pmbsr, offset, size; + struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu); + struct arm_spe_pmu_buf *buf = perf_get_aux(handle); + bool truncated, collided; + + /* + * We can be called via IRQ work trying to disable the PMU after + * a buffer full event. In this case, the aux session has already + * been stopped, so there's nothing to do here. + */ + if (!buf) + return false; + + /* + * Work out how much data has been written since the last update + * to the head index. + */ + pmbptr = round_down(read_sysreg_s(PMBPTR_EL1), spe_pmu->align); + offset = pmbptr - (u64)buf->base; + size = offset - PERF_IDX2OFF(handle->head, buf); + + if (buf->snapshot) + handle->head = offset; + + /* + * If there isn't a pending management event and we're not stopping + * the current session, then just leave everything alone. + */ + pmbsr = read_sysreg_s(PMBSR_EL1); + if (!arm_spe_pmu_buffer_mgmt_pending(pmbsr) && resume) + return false; /* Spurious IRQ */ + + /* + * Either the buffer is full or we're stopping the session. Check + * that we didn't write a partial record, since this can result + * in unparseable trace and we must disable the event. + */ + collided = pmbsr & BIT(PMBSR_EL1_COLL_SHIFT); + truncated = pmbsr & BIT(PMBSR_EL1_DL_SHIFT); + perf_aux_output_end(handle, size, + (truncated ? PERF_AUX_FLAG_TRUNCATED : 0) | + (collided ? PERF_AUX_FLAG_COLLISION : 0)); + + /* + * If we're not resuming the session, then we can clear the fault + * and we're done, otherwise we need to start a new session. + */ + if (!resume) + write_sysreg_s(0, PMBSR_EL1); + else if (!truncated) + arm_spe_perf_aux_output_begin(handle, event); + + return true; +} + +/* IRQ handling */ +static irqreturn_t arm_spe_pmu_irq_handler(int irq, void *dev) +{ + struct perf_output_handle *handle = dev; + + if (!perf_get_aux(handle)) + return IRQ_NONE; + + if (!arm_spe_perf_aux_output_end(handle, handle->event, true)) + return IRQ_NONE; + + irq_work_run(); + isb(); /* Ensure the buffer is disabled if data loss has occurred */ + write_sysreg_s(0, 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) & PMSEVFR_EL1_RES0) + return -EOPNOTSUPP; + + if (event->hw.sample_period < spe_pmu->min_period || + event->hw.sample_period & PMSIRR_EL1_IVAL_MASK) + 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, force the user to specify a + * sample period instead. + */ + if (attr->freq) + return -EINVAL; + + if (is_kernel_in_hyp_mode()) { + if (attr->exclude_kernel != attr->exclude_hv) + return -EOPNOTSUPP; + } else if (!attr->exclude_hv) { + return -EOPNOTSUPP; + } + + reg = arm_spe_event_to_pmsfcr(event); + if ((reg & BIT(PMSFCR_EL1_FE_SHIFT)) && + !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT)) + return -EOPNOTSUPP; + + if ((reg & BIT(PMSFCR_EL1_FT_SHIFT)) && + !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP)) + return -EOPNOTSUPP; + + if ((reg & BIT(PMSFCR_EL1_FL_SHIFT)) && + !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT)) + return -EOPNOTSUPP; + + 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, PMSFCR_EL1); + + reg = arm_spe_event_to_pmsevfr(event); + write_sysreg_s(reg, PMSEVFR_EL1); + + reg = arm_spe_event_to_pmslatfr(event); + write_sysreg_s(reg, PMSLATFR_EL1); + + if (flags & PERF_EF_RELOAD) { + reg = arm_spe_event_to_pmsirr(event); + write_sysreg_s(reg, PMSIRR_EL1); + isb(); + reg = local64_read(&hwc->period_left); + write_sysreg_s(reg, PMSICR_EL1); + } + + reg = arm_spe_event_to_pmscr(event); + isb(); + write_sysreg_s(reg, PMSCR_EL1); +} + +static void arm_spe_pmu_disable_and_drain_local(void) +{ + /* Disable profiling at EL0 and EL1 */ + write_sysreg_s(0, PMSCR_EL1); + isb(); + + /* Drain any buffered data */ + psb_csync(); + dsb(nsh); + + /* Disable the profiling buffer */ + write_sysreg_s(0, PMBLIMITR_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) { + /* Ensure hardware updates to PMBPTR_EL1 are visible */ + isb(); + arm_spe_perf_aux_output_end(handle, event, false); + /* + * 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(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 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; + + 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) { + .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", DRVNAME, 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(PMBIDR_EL1); + if (reg & BIT(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 >> PMBIDR_EL1_ALIGN_SHIFT & 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(PMSIDR_EL1); + if (reg & BIT(PMSIDR_EL1_FE_SHIFT)) + spe_pmu->features |= SPE_PMU_FEAT_FILT_EVT; + + if (reg & BIT(PMSIDR_EL1_FT_SHIFT)) + spe_pmu->features |= SPE_PMU_FEAT_FILT_TYP; + + if (reg & BIT(PMSIDR_EL1_FL_SHIFT)) + spe_pmu->features |= SPE_PMU_FEAT_FILT_LAT; + + if (reg & BIT(PMSIDR_EL1_ARCHINST_SHIFT)) + spe_pmu->features |= SPE_PMU_FEAT_ARCH_INST; + + if (reg & BIT(PMSIDR_EL1_LDS_SHIFT)) + spe_pmu->features |= SPE_PMU_FEAT_LDS; + + if (reg & BIT(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 >> PMSIDR_EL1_INTERVAL_SHIFT & 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 >> PMSIDR_EL1_MAXSIZE_SHIFT & 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 >> PMSIDR_EL1_COUNTSIZE_SHIFT & PMSIDR_EL1_COUNTSIZE_MASK; + switch (fld) { + default: + dev_warn(dev, "unknown PMSIDR_EL1.CountSize [%d]; assuming 2\n", + fld); + /* Fallthrough */ + case 2: + spe_pmu->cnt_width = 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, PMBPTR_EL1); + isb(); + + /* Clear any pending management interrupts */ + write_sysreg_s(0, 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; + + /* Keep the hotplug state steady whilst we probe */ + get_online_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)) { + ret = -ENXIO; + goto out_put_cpus; + } + + /* 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) + goto out_put_cpus; + + /* Setup the CPUs in our mask -- this enables the IRQ */ + on_each_cpu_mask(mask, __arm_spe_pmu_setup_one, spe_pmu, 1); + + /* Register our hotplug notifier now so we don't miss any events */ + ret = cpuhp_state_add_instance_nocalls(arm_spe_pmu_online, + &spe_pmu->hotplug_node); +out_put_cpus: + put_online_cpus(); + return ret; +} + +/* 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,arm-spe-pmu-v1", .data = (void *)1 }, +}; + +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_free_handle; + + return 0; + +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); + cpumask_t *mask = &spe_pmu->supported_cpus; + + arm_spe_pmu_perf_destroy(spe_pmu); + + get_online_cpus(); + cpuhp_state_remove_instance_nocalls(arm_spe_pmu_online, + &spe_pmu->hotplug_node); + on_each_cpu_mask(mask, __arm_spe_pmu_stop_one, spe_pmu, 1); + free_percpu_irq(spe_pmu->irq, spe_pmu->handle); + free_percpu(spe_pmu->handle); + put_online_cpus(); + + 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 <[email protected]>"); +MODULE_LICENSE("GPL v2"); -- 2.1.4
