diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-tmc-etf.c')
-rw-r--r-- | drivers/hwtracing/coresight/coresight-tmc-etf.c | 82 |
1 files changed, 64 insertions, 18 deletions
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index a5f053f2db2c..2527b5d3b65e 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -4,6 +4,7 @@ * Author: Mathieu Poirier <mathieu.poirier@linaro.org> */ +#include <linux/atomic.h> #include <linux/circ_buf.h> #include <linux/coresight.h> #include <linux/perf_event.h> @@ -180,8 +181,10 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev) * sink is already enabled no memory is needed and the HW need not be * touched. */ - if (drvdata->mode == CS_MODE_SYSFS) + if (drvdata->mode == CS_MODE_SYSFS) { + atomic_inc(csdev->refcnt); goto out; + } /* * If drvdata::buf isn't NULL, memory was allocated for a previous @@ -200,11 +203,13 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev) } ret = tmc_etb_enable_hw(drvdata); - if (!ret) + if (!ret) { drvdata->mode = CS_MODE_SYSFS; - else + atomic_inc(csdev->refcnt); + } else { /* Free up the buffer if we failed to enable */ used = false; + } out: spin_unlock_irqrestore(&drvdata->spinlock, flags); @@ -218,6 +223,7 @@ out: static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data) { int ret = 0; + pid_t pid; unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); struct perf_output_handle *handle = data; @@ -228,19 +234,42 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data) if (drvdata->reading) break; /* - * In Perf mode there can be only one writer per sink. There - * is also no need to continue if the ETB/ETF is already - * operated from sysFS. + * No need to continue if the ETB/ETF is already operated + * from sysFS. */ - if (drvdata->mode != CS_MODE_DISABLED) + if (drvdata->mode == CS_MODE_SYSFS) { + ret = -EBUSY; + break; + } + + /* Get a handle on the pid of the process to monitor */ + pid = task_pid_nr(handle->event->owner); + + if (drvdata->pid != -1 && drvdata->pid != pid) { + ret = -EBUSY; break; + } ret = tmc_set_etf_buffer(csdev, handle); if (ret) break; + + /* + * No HW configuration is needed if the sink is already in + * use for this session. + */ + if (drvdata->pid == pid) { + atomic_inc(csdev->refcnt); + break; + } + ret = tmc_etb_enable_hw(drvdata); - if (!ret) + if (!ret) { + /* Associate with monitored process. */ + drvdata->pid = pid; drvdata->mode = CS_MODE_PERF; + atomic_inc(csdev->refcnt); + } } while (0); spin_unlock_irqrestore(&drvdata->spinlock, flags); @@ -273,26 +302,34 @@ static int tmc_enable_etf_sink(struct coresight_device *csdev, return 0; } -static void tmc_disable_etf_sink(struct coresight_device *csdev) +static int tmc_disable_etf_sink(struct coresight_device *csdev) { unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); spin_lock_irqsave(&drvdata->spinlock, flags); + if (drvdata->reading) { spin_unlock_irqrestore(&drvdata->spinlock, flags); - return; + return -EBUSY; } - /* Disable the TMC only if it needs to */ - if (drvdata->mode != CS_MODE_DISABLED) { - tmc_etb_disable_hw(drvdata); - drvdata->mode = CS_MODE_DISABLED; + if (atomic_dec_return(csdev->refcnt)) { + spin_unlock_irqrestore(&drvdata->spinlock, flags); + return -EBUSY; } + /* Complain if we (somehow) got out of sync */ + WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED); + tmc_etb_disable_hw(drvdata); + /* Dissociate from monitored process. */ + drvdata->pid = -1; + drvdata->mode = CS_MODE_DISABLED; + spin_unlock_irqrestore(&drvdata->spinlock, flags); dev_dbg(drvdata->dev, "TMC-ETB/ETF disabled\n"); + return 0; } static int tmc_enable_etf_link(struct coresight_device *csdev, @@ -337,10 +374,11 @@ static void tmc_disable_etf_link(struct coresight_device *csdev, dev_dbg(drvdata->dev, "TMC-ETF disabled\n"); } -static void *tmc_alloc_etf_buffer(struct coresight_device *csdev, int cpu, - void **pages, int nr_pages, bool overwrite) +static void *tmc_alloc_etf_buffer(struct coresight_device *csdev, + struct perf_event *event, void **pages, + int nr_pages, bool overwrite) { - int node; + int node, cpu = event->cpu; struct cs_buffers *buf; if (cpu == -1) @@ -400,7 +438,7 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, u32 *buf_ptr; u64 read_ptr, write_ptr; u32 status; - unsigned long offset, to_read; + unsigned long offset, to_read = 0, flags; struct cs_buffers *buf = sink_config; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); @@ -411,6 +449,12 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, if (WARN_ON_ONCE(drvdata->mode != CS_MODE_PERF)) return 0; + spin_lock_irqsave(&drvdata->spinlock, flags); + + /* Don't do anything if another tracer is using this sink */ + if (atomic_read(csdev->refcnt) != 1) + goto out; + CS_UNLOCK(drvdata->base); tmc_flush_and_stop(drvdata); @@ -504,6 +548,8 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, to_read = buf->nr_pages << PAGE_SHIFT; } CS_LOCK(drvdata->base); +out: + spin_unlock_irqrestore(&drvdata->spinlock, flags); return to_read; } |