From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Doug Anderson <dianders@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>, Al Grant <al.grant@arm.com>,
Denis Nikitin <denik@chromium.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
coresight@lists.linaro.org,
Mattias Nissler <mnissler@chromium.org>,
LKML <linux-kernel@vger.kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Stephen Boyd <swboyd@chromium.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>, Leo Yan <leo.yan@linaro.org>,
Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Mike Leach <mike.leach@linaro.org>
Subject: Re: [PATCHv2 3/4] coresight: etm4x: Add support to exclude kernel mode tracing
Date: Tue, 02 Mar 2021 12:11:37 +0530 [thread overview]
Message-ID: <2da60c28dcaecfc2cb7bcd25840ffcbe@codeaurora.org> (raw)
In-Reply-To: <CAD=FV=XCi_+yW6DPeUYmtjMhn-qpjMiB0E4_Qkz6d_e6G-CoVA@mail.gmail.com>
On 2021-03-02 04:13, Doug Anderson wrote:
> Hi,
>
> On Mon, Mar 1, 2021 at 11:05 AM Sai Prakash Ranjan
> <saiprakash.ranjan@codeaurora.org> wrote:
>>
>> On production systems with ETMs enabled, it is preferred to exclude
>> kernel mode(NS EL1) tracing for security concerns and support only
>> userspace(NS EL0) tracing. Perf subsystem interface uses the newly
>> introduced kernel config CONFIG_EXCLUDE_KERNEL_PMU_TRACE to exclude
>> kernel mode tracing, but there is an additional interface via sysfs
>> for ETMs which also needs to be handled to exclude kernel
>> mode tracing. So we use this same generic kernel config to handle
>> the sysfs mode of tracing. This config is disabled by default and
>> would not affect the current configuration which has both kernel and
>> userspace tracing enabled by default.
>>
>> Tested-by: Denis Nikitin <denik@chromium.org>
>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>> ---
>> drivers/hwtracing/coresight/coresight-etm4x-core.c | 6 +++++-
>> drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 6 ++++++
>> 2 files changed, 11 insertions(+), 1 deletion(-)
>
> Not that I'm an expert in the perf subsystem, but the concern I had
> with v1 is now addressed. FWIW this seems fine to me now.
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>
Thanks Doug.
>
>> --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>> +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
>> @@ -296,6 +296,12 @@ static ssize_t mode_store(struct device *dev,
>> if (kstrtoul(buf, 16, &val))
>> return -EINVAL;
>>
>> + if (IS_ENABLED(CONFIG_EXCLUDE_KERNEL_PMU_TRACE) && (!(val &
>> ETM_MODE_EXCL_KERN))) {
>> + dev_warn(dev,
>> + "Kernel mode tracing is not allowed, check
>> your kernel config\n");
>
> slight nit that I think your string needs to be indented by 1 space.
> ;-)
>
Ah yes, I will have to post v3 anyways to fix commit message in Patch 2
after I get few more feedback for other patches, I will fix this up as
well.
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2021-03-02 8:27 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 19:04 [PATCHv2 0/4] perf/core: Add support to exclude kernel mode PMU tracing Sai Prakash Ranjan
2021-03-01 19:04 ` [PATCHv2 1/4] " Sai Prakash Ranjan
2021-03-01 22:42 ` Doug Anderson
2021-03-01 19:04 ` [PATCHv2 2/4] perf evsel: Print warning for excluding kernel mode instruction tracing Sai Prakash Ranjan
2021-03-01 22:43 ` Doug Anderson
2021-03-02 6:45 ` Sai Prakash Ranjan
2021-03-01 19:04 ` [PATCHv2 3/4] coresight: etm4x: Add support to exclude kernel mode tracing Sai Prakash Ranjan
2021-03-01 22:43 ` Doug Anderson
2021-03-02 6:41 ` Sai Prakash Ranjan [this message]
2021-03-01 19:04 ` [PATCHv2 4/4] coresight: etm3x: " Sai Prakash Ranjan
2021-03-01 22:43 ` Doug Anderson
2021-03-02 6:46 ` Sai Prakash Ranjan
2021-03-04 19:59 ` [PATCHv2 0/4] perf/core: Add support to exclude kernel mode PMU tracing Andi Kleen
2021-03-04 20:17 ` Andi Kleen
2021-03-09 6:38 ` Sai Prakash Ranjan
2021-03-09 14:44 ` Andi Kleen
2021-03-10 15:17 ` Sai Prakash Ranjan
2021-06-10 13:28 ` Mattias Nissler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2da60c28dcaecfc2cb7bcd25840ffcbe@codeaurora.org \
--to=saiprakash.ranjan@codeaurora.org \
--cc=acme@kernel.org \
--cc=al.grant@arm.com \
--cc=alexander.shishkin@linux.intel.com \
--cc=coresight@lists.linaro.org \
--cc=denik@chromium.org \
--cc=dianders@chromium.org \
--cc=jolsa@redhat.com \
--cc=leo.yan@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mathieu.poirier@linaro.org \
--cc=mike.leach@linaro.org \
--cc=mingo@redhat.com \
--cc=mnissler@chromium.org \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
--cc=suzuki.poulose@arm.com \
--cc=swboyd@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).