This patch uses the PMU driver configuration held in event::hw::drv_config to select a sink for each event that is created (the old sysFS way of working is kept around for backward compatibility).
By proceeding in this way a sink can be used by multiple sessions without having to play games with entries in sysFS. Signed-off-by: Mathieu Poirier <[email protected]> --- drivers/hwtracing/coresight/coresight-etm-perf.c | 130 ++++++++++++++++++++--- drivers/hwtracing/coresight/coresight-etm-perf.h | 4 + 2 files changed, 122 insertions(+), 12 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 0f5e03e4df22..5c2cce60da5e 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -11,6 +11,7 @@ #include <linux/list.h> #include <linux/mm.h> #include <linux/init.h> +#include <linux/parser.h> #include <linux/perf_event.h> #include <linux/slab.h> #include <linux/types.h> @@ -22,6 +23,8 @@ static struct pmu etm_pmu; static bool etm_perf_up; +#define CORESIGHT_DEVICE_MAX_NAME_LEN 256 + /** * struct etm_event_data - Coresight specifics associated to an event * @work: Handle to free allocated memory outside IRQ context. @@ -181,6 +184,74 @@ static void etm_free_aux(void *data) schedule_work(&event_data->work); } +static char *etm_drv_config_sync(struct perf_event *event) +{ + char *sink; + int node = event->cpu == -1 ? -1 : cpu_to_node(event->cpu); + struct pmu_drv_config *drv_config = perf_event_get_drv_config(event); + + sink = kmalloc_node(CORESIGHT_DEVICE_MAX_NAME_LEN, GFP_KERNEL, node); + if (!sink) + return NULL; + + /* + * Make sure we don't race with perf_drv_config_replace() in + * kernel/events/core.c. + */ + raw_spin_lock(&drv_config->lock); + memcpy(sink, drv_config->config, CORESIGHT_DEVICE_MAX_NAME_LEN); + raw_spin_unlock(&drv_config->lock); + + return sink; +} + +static struct coresight_device *etm_event_get_sink(struct perf_event *event) +{ + struct pmu_drv_config *drv_config = perf_event_get_drv_config(event); + + /* + * Try the preferred method first, i.e getting the sink information + * using the ioctl() method. + */ + if (drv_config->config) { + char *drv_config; + struct device *dev; + struct coresight_device *sink; + + /* + * Get sink from event->hw.drv_config.config - see + * _perf_ioctl() _SET_DRV_CONFIG. + */ + drv_config = etm_drv_config_sync(event); + if (!drv_config) + goto out; + + /* Look for the device of that name on the CS bus. */ + dev = bus_find_device_by_name(&coresight_bustype, NULL, + drv_config); + kfree(drv_config); + + if (dev) { + sink = to_coresight_device(dev); + /* Put reference from 'bus_find_device()' */ + put_device(dev); + return sink; + } + } + + /* + * No luck with the above method, so we are working with an older user + * space. See if a sink has been set using sysFS. If this is the case + * CPU-wide session will only be able to use a single sink. + * + * When operated from sysFS users are responsible to enable the sink + * while from perf, the perf tools will do it based on the choice made + * on the cmd line. As such the "enable_sink" flag in sysFS is reset. + */ +out: + return coresight_get_enabled_sink(true); +} + static void *etm_setup_aux(struct perf_event *event, void **pages, int nr_pages, bool overwrite) { @@ -194,18 +265,8 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, return NULL; INIT_WORK(&event_data->work, free_event_data); - /* - * In theory nothing prevent tracers in a trace session from being - * associated with different sinks, nor having a sink per tracer. But - * until we have HW with this kind of topology we need to assume tracers - * in a trace session are using the same sink. Therefore go through - * the coresight bus and pick the first enabled sink. - * - * When operated from sysFS users are responsible to enable the sink - * while from perf, the perf tools will do it based on the choice made - * on the cmd line. As such the "enable_sink" flag in sysFS is reset. - */ - sink = coresight_get_enabled_sink(true); + /* First get the sink to use for this event */ + sink = etm_event_get_sink(event); if (!sink) goto err; @@ -442,6 +503,49 @@ static void etm_addr_filters_sync(struct perf_event *event) filters->nr_filters = i; } +static const match_table_t config_tokens = { + { ETM_CFG_SINK, "%u.%s" }, + { ETM_CFG_NONE, NULL }, +}; + +static void *etm_drv_config_validate(struct perf_event *event, char *cstr) +{ + char *str, *to_parse, *sink = NULL; + int token, ret = -EINVAL; + substring_t args[MAX_OPT_ARGS]; + + to_parse = kstrdup(cstr, GFP_KERNEL); + if (!to_parse) + return ERR_PTR(-ENOMEM); + + while ((str = strsep(&to_parse, " ,\n")) != NULL) { + if (!*str) + continue; + + token = match_token(str, config_tokens, args); + switch (token) { + case ETM_CFG_SINK: + sink = kstrdup(str, GFP_KERNEL); + if (!sink) { + ret = -ENOMEM; + goto out; + } + break; + default: + goto out; + } + } + +out: + kfree(to_parse); + return sink ? sink : ERR_PTR(ret); +} + +static void etm_drv_config_free(void *drv_data) +{ + kfree(drv_data); +} + int etm_perf_symlink(struct coresight_device *csdev, bool link) { char entry[sizeof("cpu9999999")]; @@ -486,6 +590,8 @@ static int __init etm_perf_init(void) etm_pmu.addr_filters_sync = etm_addr_filters_sync; etm_pmu.addr_filters_validate = etm_addr_filters_validate; etm_pmu.nr_addr_filters = ETM_ADDR_CMP_MAX; + etm_pmu.drv_config_validate = etm_drv_config_validate; + etm_pmu.drv_config_free = etm_drv_config_free; ret = perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1); if (ret == 0) diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h index 4197df4faf5e..37a98230fc34 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.h +++ b/drivers/hwtracing/coresight/coresight-etm-perf.h @@ -42,6 +42,10 @@ struct etm_filters { bool ssstatus; }; +enum etm_config_elem_type { + ETM_CFG_NONE = -1, + ETM_CFG_SINK, +}; #ifdef CONFIG_CORESIGHT int etm_perf_symlink(struct coresight_device *csdev, bool link); -- 2.7.4
