From 13af88f312fc57becacfcbb1cc77f844281a30ec Mon Sep 17 00:00:00 2001 From: Yabin Cui Date: Thu, 29 Aug 2019 14:28:38 -0600 Subject: coresight: tmc-etr: Fix updating buffer in not-snapshot mode. TMC etr always copies all available data to perf aux buffer, which may exceed the available space in perf aux buffer. It isn't suitable for not-snapshot mode, because: 1) It may overwrite previously written data. 2) It may make the perf_event_mmap_page->aux_head report having more or less data than the reality. So change to only copy the latest data fitting the available space in perf aux buffer. Signed-off-by: Yabin Cui Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20190829202842.580-14-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 2246c1e6744a..f835a3c78b37 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1414,9 +1414,10 @@ free_etr_perf_buffer: * tmc_etr_sync_perf_buffer: Copy the actual trace data from the hardware * buffer to the perf ring buffer. */ -static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf) +static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf, + unsigned long to_copy) { - long bytes, to_copy; + long bytes; long pg_idx, pg_offset, src_offset; unsigned long head = etr_perf->head; char **dst_pages, *src_buf; @@ -1426,8 +1427,7 @@ 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; - to_copy = etr_buf->len; + src_offset = etr_buf->offset + etr_buf->len - to_copy; while (to_copy > 0) { /* @@ -1438,6 +1438,8 @@ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf) * 3) what is available in the destination page. * in one iteration. */ + if (src_offset >= etr_buf->size) + src_offset -= etr_buf->size; bytes = tmc_etr_buf_get_data(etr_buf, src_offset, to_copy, &src_buf); if (WARN_ON_ONCE(bytes <= 0)) @@ -1458,8 +1460,6 @@ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf) /* Move source pointers */ src_offset += bytes; - if (src_offset >= etr_buf->size) - src_offset -= etr_buf->size; } } @@ -1505,7 +1505,11 @@ tmc_update_etr_buffer(struct coresight_device *csdev, spin_unlock_irqrestore(&drvdata->spinlock, flags); size = etr_buf->len; - tmc_etr_sync_perf_buffer(etr_perf); + if (!etr_perf->snapshot && size > handle->size) { + size = handle->size; + lost = true; + } + tmc_etr_sync_perf_buffer(etr_perf, size); /* * In snapshot mode we simply increment the head by the number of byte -- cgit v1.2.3-58-ga151