From: Leo Yan Date: Tue, 1 Apr 2025 18:07:06 +0000 (+0100) Subject: coresight: tmc: Re-enable sink after buffer update X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d5f7e4bea90f2e0630b0c76b0f6cf64304c5b514;p=users%2Fdwmw2%2Flinux.git coresight: tmc: Re-enable sink after buffer update The buffer update callbacks disable the sink before syncing data but misses to re-enable it afterward. This is fine in the general flow, because the sink will be re-enabled the next time the PMU event is activated. However, during AUX pause and resume, if the sink is disabled in the buffer update callback, there is no chance to re-enable it when AUX resumes. To address this, the callbacks now check the event state 'event->hw.state'. If the event is an active state (0), the sink is re-enabled. For the TMC ETR driver, buffer updates are not fully protected by the driver's spinlock. In this case, the sink is not re-enabled if its reference counter is 0, in order to avoid race conditions where the sink may have been completely disabled. Signed-off-by: Leo Yan Reviewed-by: Mike Leach Reviewed-by: James Clark Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20250401180708.385396-6-leo.yan@arm.com --- diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index d858740001c27..7584cc03d8e60 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -482,6 +482,7 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, unsigned long offset, to_read = 0, flags; struct cs_buffers *buf = sink_config; struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); + struct perf_event *event = handle->event; if (!buf) return 0; @@ -586,6 +587,14 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, * is expected by the perf ring buffer. */ CS_LOCK(drvdata->base); + + /* + * If the event is active, it is triggered during an AUX pause. + * Re-enable the sink so that it is ready when AUX resume is invoked. + */ + if (!event->hw.state) + __tmc_etb_enable_hw(drvdata); + out: raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 3f31ad2ae65d2..b07fcdb3fe1a8 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1634,6 +1634,7 @@ tmc_update_etr_buffer(struct coresight_device *csdev, struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); struct etr_perf_buffer *etr_perf = config; struct etr_buf *etr_buf = etr_perf->etr_buf; + struct perf_event *event = handle->event; raw_spin_lock_irqsave(&drvdata->spinlock, flags); @@ -1703,6 +1704,15 @@ tmc_update_etr_buffer(struct coresight_device *csdev, */ smp_wmb(); + /* + * If the event is active, it is triggered during an AUX pause. + * Re-enable the sink so that it is ready when AUX resume is invoked. + */ + raw_spin_lock_irqsave(&drvdata->spinlock, flags); + if (csdev->refcnt && !event->hw.state) + __tmc_etr_enable_hw(drvdata); + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); + out: /* * Don't set the TRUNCATED flag in snapshot mode because 1) the