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authorYabin Cui <yabinc@google.com>2019-08-29 14:28:38 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-09-03 22:01:17 +0200
commit13af88f312fc57becacfcbb1cc77f844281a30ec (patch)
tree18aac4c7b5bb7c26325f1be6c46f0fb241d3bf85 /drivers/hwtracing
parent89e89b05ef5b58ab33070cc5b59d74ca8cff86fe (diff)
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 <yabinc@google.com> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20190829202842.580-14-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/coresight/coresight-tmc-etr.c18
1 files 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