From: Srinivasarao Pathipati <quic_c_spathi@quicinc.com>
To: Will Deacon <will@kernel.org>
Cc: <mark.rutland@arm.com>, <peterz@infradead.org>,
<mingo@redhat.com>, <acme@kernel.org>,
<alexander.shishkin@linux.intel.com>, <jolsa@kernel.org>,
<namhyung@kernel.org>, <catalin.marinas@arm.com>,
<linux-arm-kernel@lists.infradead.org>,
<linux-perf-users@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V5] arm64: perf: Make exporting of pmu events configurable
Date: Thu, 9 Jun 2022 16:05:20 +0530 [thread overview]
Message-ID: <4f5dbc00-e25b-f6ff-8585-31fc50f48a21@quicinc.com> (raw)
In-Reply-To: <20220609100247.GA2187@willie-the-truck>
On our Qualcomm platforms, The X bit is getting set by firmware at early
bootup for Qualcomm use cases
and non-secure world is resetting it, that causing issue.
On 6/9/2022 3:32 PM, Will Deacon wrote:
> On Mon, May 23, 2022 at 05:19:34PM +0530, Srinivasarao Pathipati wrote:
>> The PMU export bit (PMCR_EL0.X) is getting reset during pmu reset,
>> Make is configurable using sysctls to enable/disable at runtime.
>> It can also be enabled at early bootup with kernel arguments.
>>
>> Signed-off-by: Srinivasarao Pathipati <quic_c_spathi@quicinc.com>
>> ---
>> Changes since V4:
>> - Registering sysctls dynamically for only arm64 as suggested by Will
>> - Not removed the code to configure with kernel parameters
>> as the sysctl's kernel parameter(sysctl.kernel.export_pmu_events)
>> is not working at early bootup. pmu_reset() getting called before
>> sysctl's kernel parameter is set.
> Why do you need this during early bootup? Perf won't program any events
> until much later and if somebody else is configuring the PMU before
> entering Linux then they can also set that X bit in the PMCR.
>
> Will
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-06-09 10:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-23 11:49 [PATCH V5] arm64: perf: Make exporting of pmu events configurable Srinivasarao Pathipati
2022-06-09 5:02 ` Srinivasarao Pathipati
2022-06-09 10:02 ` Will Deacon
2022-06-09 10:35 ` Srinivasarao Pathipati [this message]
2022-06-09 11:32 ` Will Deacon
2022-06-09 13:07 ` Srinivasarao Pathipati
2022-06-09 11:36 ` Robin Murphy
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=4f5dbc00-e25b-f6ff-8585-31fc50f48a21@quicinc.com \
--to=quic_c_spathi@quicinc.com \
--cc=acme@kernel.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=catalin.marinas@arm.com \
--cc=jolsa@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-perf-users@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
--cc=will@kernel.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