From: Leo Yan <leo.yan@linaro.org>
To: Mathieu Poirier <mathieu.poirier@linaro.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v2 4/4] coresight: etm3x: Don't trace PID for non-root PID namespace
Date: Mon, 13 Dec 2021 20:13:23 +0800 [thread overview]
Message-ID: <20211213121323.1887180-5-leo.yan@linaro.org> (raw)
In-Reply-To: <20211213121323.1887180-1-leo.yan@linaro.org>
ETMv3 driver enables PID tracing by directly using perf config from
userspace, this means the tracer will capture PID packets from root
namespace but the profiling session runs in non-root PID namespace.
Finally, the recorded packets can mislead perf reporting with the
mismatched PID values.
This patch changes to only enable PID tracing for root PID namespace.
Note, the hardware supports VMID tracing from ETMv3.5, but the driver
never enables VMID trace, this patch doesn't handle VMID trace (bit 30
in ETMCR register) particularly.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
drivers/hwtracing/coresight/coresight-etm3x-core.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index cf64ce73a741..7d413ba8b823 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -340,6 +340,10 @@ static int etm_parse_event_config(struct etm_drvdata *drvdata,
config->ctrl = attr->config;
+ /* Don't trace contextID when runs in non-root PID namespace */
+ if (!task_is_in_init_pid_ns(current))
+ config->ctrl &= ~ETMCR_CTXID_SIZE;
+
/*
* Possible to have cores with PTM (supports ret stack) and ETM
* (never has ret stack) on the same SoC. So if we have a request
--
2.25.1
next prev parent reply other threads:[~2021-12-13 12:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-13 12:13 [PATCH v2 0/4] coresight: etm: Correct PID tracing for non-root namespace Leo Yan
2021-12-13 12:13 ` [PATCH v2 1/4] coresight: etm4x: Add lock for reading virtual context ID comparator Leo Yan
2021-12-13 12:13 ` [PATCH v2 2/4] coresight: etm4x: Don't use virtual contextID for non-root PID namespace Leo Yan
2021-12-13 19:47 ` kernel test robot
2021-12-13 12:13 ` [PATCH v2 3/4] coresight: etm4x: Don't trace PID " Leo Yan
2021-12-13 21:45 ` kernel test robot
2021-12-13 12:13 ` Leo Yan [this message]
2021-12-13 19:16 ` [PATCH v2 4/4] coresight: etm3x: " kernel test robot
2021-12-14 4:46 ` Leo Yan
2021-12-16 8:54 ` Rong Chen
2021-12-14 10:59 ` [PATCH v2 0/4] coresight: etm: Correct PID tracing for non-root namespace Suzuki K Poulose
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=20211213121323.1887180-5-leo.yan@linaro.org \
--to=leo.yan@linaro.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=coresight@lists.linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.poirier@linaro.org \
--cc=mike.leach@linaro.org \
--cc=suzuki.poulose@arm.com \
/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).