On 20/10/17 13:34, Julien Thierry wrote:
Hi Suzuki,
On 19/10/17 18:15, Suzuki K Poulose wrote:
At the moment we adjust the buffer pointers for reading the trace data via misc device in the common code for ETF/ETB and ETR. Since we are going to change how we manage the buffer for ETR, let us move the buffer manipulation to the respective driver files, hiding it from the common code. We do so by adding type specific helpers for finding the length of data and the pointer to the buffer, for a given length at a file position.
Cc: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com
drivers/hwtracing/coresight/coresight-tmc-etf.c | 16 ++++++++++++ drivers/hwtracing/coresight/coresight-tmc-etr.c | 33 ++++++++++++++++++++++++ drivers/hwtracing/coresight/coresight-tmc.c | 34 ++++++++++++++----------- drivers/hwtracing/coresight/coresight-tmc.h | 4 +++ 4 files changed, 72 insertions(+), 15 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index e2513b786242..0b6f1eb746de 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -120,6 +120,22 @@ static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata) CS_LOCK(drvdata->base); } +/*
- Return the available trace data in the buffer from @pos, with
- a maximum limit of @len, updating the @bufpp on where to
- find it.
- */
+ssize_t tmc_etb_get_sysfs_trace(struct tmc_drvdata *drvdata, + loff_t pos, size_t len, char **bufpp) +{ + /* Adjust the len to available size @pos */ + if (pos + len > drvdata->len) + len = drvdata->len - pos; + if (len > 0)
Do we have some guarantee that "pos <= drvdata->len"? because since len is unsigned this check only covers the case were len is 0.
Maybe it would be better to use a signed variable to store the result of the difference.
+ *bufpp = drvdata->buf + pos;
- Return the available trace data in the buffer @pos, with a maximum
- limit of @len, also updating the @bufpp on where to find it.
- */
+ssize_t tmc_etr_get_sysfs_trace(struct tmc_drvdata *drvdata, + loff_t pos, size_t len, char **bufpp) +{ + char *bufp = drvdata->buf + pos; + char *bufend = (char *)(drvdata->vaddr + drvdata->size);
+ /* Adjust the len to available size @pos */ + if (pos + len > drvdata->len) + len = drvdata->len - pos;
+ if (len <= 0) + return len;
Similar issue here.
Thanks for spotting. I will fix it.
Cheers