Perf cs_etm session executed unexpectedly when AUX buffer > 1G.
perf record -C 0 -m ,2G -e cs_etm// -- <workload> [ perf record: Captured and wrote 2.615 MB perf.data ]
Perf only collect about 2M perf data rather than 2G. This is becasuse the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The overflow cause buffer allocation to fail, and TMC driver will alloc minimal buffer size(1M). You can just get about 2M perf data(1M AUX buffer + perf data header) at least.
Explicit convert nr_pages to 64 bit to avoid overflow.
Signed-off-by: Ruidong Tian tianruidong@linux.alibaba.com Reviewed-by: James Clark james.clark@arm.com --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +- drivers/hwtracing/coresight/coresight-tmc.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 766325de0e29..1425ecd1cf78 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1267,7 +1267,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event, * than the size requested via sysfs. */ if ((nr_pages << PAGE_SHIFT) > drvdata->size) { - etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT), + etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT), 0, node, NULL); if (!IS_ERR(etr_buf)) goto done; diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index b97da39652d2..0ee48c5ba764 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table, static inline unsigned long tmc_sg_table_buf_size(struct tmc_sg_table *sg_table) { - return sg_table->data_pages.nr_pages << PAGE_SHIFT; + return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT; }
struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);