From c3595fdc729fecb21d3b1c6ce4a32420ff603c29 Mon Sep 17 00:00:00 2001 From: Yabin Cui Date: Thu, 29 Aug 2019 14:28:38 -0600 Subject: [PATCH] UPSTREAM: coresight: tmc-etr: Fix updating buffer in not-snapshot mode. (Upstream commit 13af88f312fc57becacfcbb1cc77f844281a30ec). 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 Bug: 140266694 Change-Id: Idcdd505c77637d0dc3329a1d145ddca20ca895da Signed-off-by: Yabin Cui --- .../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 46e37437ae47..2153c3ffad15 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1406,9 +1406,10 @@ 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; @@ -1418,8 +1419,7 @@ 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) { /* @@ -1430,6 +1430,8 @@ 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)) @@ -1450,8 +1452,6 @@ 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; } } @@ -1497,7 +1497,11 @@ 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