linux-kernel - Re: [PATCH v3] cpuidle: psci: Add trace for PSCI domain idle

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <7hy0ysi4pf.fsf@baylibre.com>
Date: Thu, 30 Jan 2025 09:36:44 -0800
From: Kevin Hilman <khilman@...nel.org>
To: Keita Morisaki <keyz@...gle.com>, rostedt@...dmis.org,
 mhiramat@...nel.org, mathieu.desnoyers@...icios.com,
 linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
 lpieralisi@...nel.org, sudeep.holla@....com, rafael@...nel.org,
 daniel.lezcano@...aro.org, linux-pm@...r.kernel.org
Cc: aarontian@...gle.com, yimingtseng@...gle.com, Keita Morisaki
 <keyz@...gle.com>
Subject: Re: [PATCH v3] cpuidle: psci: Add trace for PSCI domain idle

Keita Morisaki <keyz@...gle.com> writes:

> The trace event cpu_idle provides insufficient information for debugging
> PSCI requests due to lacking access to determined PSCI domain idle
> states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
> idle states the power domain has.
>
> Add new trace events namely psci_domain_idle_enter and
> psci_domain_idle_exit to trace enter and exit events with a determined
> idle state.
>
> These new trace events will help developers debug CPUidle issues on ARM
> systems using PSCI by providing more detailed information about the
> requested idle states.
>
> Signed-off-by: Keita Morisaki <keyz@...gle.com>
> Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>

Tested-by: Kevin Hilman <khilman@...libre.com>

I've been using some local trace_printk() to do exactly this, so I fully
support having some official tracepoints here. 

For my local hacks, I was trackin the state index as well as the state
value since for quick debug, I find the index to more human readable
than the state value, which I have to compare with the
arm,psci-suspend-pararm from the DT.

Anyways, thanks for submitting this!

Kevin