From ec13c78d7b45851d21786127ae17193f9a1446fb Mon Sep 17 00:00:00 2001 From: Mathieu Poirier Date: Thu, 29 Aug 2019 14:28:42 -0600 Subject: [PATCH] coresight: tmc-etr: Add barrier packets when moving offset forward This patch adds barrier packets in the trace stream when the offset in the data buffer needs to be moved forward. Otherwise the decoder isn't aware of the break in the stream and can't synchronise itself with the trace data. Signed-off-by: Mathieu Poirier Tested-by: Yabin Cui Reviewed-by: Leo Yan Link: https://lore.kernel.org/r/20190829202842.580-18-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 29 ++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index bae4727..625882bc 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1418,10 +1418,11 @@ free_etr_perf_buffer: * buffer to the perf ring buffer. */ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf, + unsigned long src_offset, unsigned long to_copy) { long bytes; - long pg_idx, pg_offset, src_offset; + long pg_idx, pg_offset; unsigned long head = etr_perf->head; char **dst_pages, *src_buf; struct etr_buf *etr_buf = etr_perf->etr_buf; @@ -1430,7 +1431,6 @@ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf, pg_idx = head >> PAGE_SHIFT; pg_offset = head & (PAGE_SIZE - 1); dst_pages = (char **)etr_perf->pages; - src_offset = etr_buf->offset + etr_buf->len - to_copy; while (to_copy > 0) { /* @@ -1478,7 +1478,7 @@ tmc_update_etr_buffer(struct coresight_device *csdev, void *config) { bool lost = false; - unsigned long flags, size = 0; + unsigned long flags, offset, size = 0; 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; @@ -1506,16 +1506,35 @@ tmc_update_etr_buffer(struct coresight_device *csdev, spin_unlock_irqrestore(&drvdata->spinlock, flags); lost = etr_buf->full; + offset = etr_buf->offset; size = etr_buf->len; + + /* + * The ETR buffer may be bigger than the space available in the + * perf ring buffer (handle->size). If so advance the offset so that we + * get the latest trace data. In snapshot mode none of that matters + * since we are expected to clobber stale data in favour of the latest + * traces. + */ if (!etr_perf->snapshot && size > handle->size) { - size = handle->size; + u32 mask = tmc_get_memwidth_mask(drvdata); + + /* + * Make sure the new size is aligned in accordance with the + * requirement explained in function tmc_get_memwidth_mask(). + */ + size = handle->size & mask; + offset = etr_buf->offset + etr_buf->len - size; + + if (offset >= etr_buf->size) + offset -= etr_buf->size; lost = true; } /* Insert barrier packets at the beginning, if there was an overflow */ if (lost) tmc_etr_buf_insert_barrier_packet(etr_buf, etr_buf->offset); - tmc_etr_sync_perf_buffer(etr_perf, size); + tmc_etr_sync_perf_buffer(etr_perf, offset, size); /* * In snapshot mode we simply increment the head by the number of byte -- 2.7.4