linux-kernel - Re: [PATCH V3 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

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

Message-ID: <4ad634a1b16285b4d83e7c320a5657b548fd6e22.camel@xry111.site>
Date: Fri, 23 Aug 2024 14:34:01 +0800
From: Xi Ruoyao <xry111@...111.site>
To: Huacai Chen <chenhuacai@...ngson.cn>, "Rafael J . Wysocki"
	 <rafael@...nel.org>, Viresh Kumar <viresh.kumar@...aro.org>, Huacai Chen
	 <chenhuacai@...nel.org>
Cc: loongarch@...ts.linux.dev, linux-pm@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Xuerui Wang <kernel@...0n.name>, Jiaxun Yang
	 <jiaxun.yang@...goat.com>, Binbin Zhou <zhoubinbin@...ngson.cn>
Subject: Re: [PATCH V3 2/2] cpufreq: Add Loongson-3 CPUFreq driver support

On Fri, 2024-07-05 at 14:06 +0800, Huacai Chen wrote:
> Some of LoongArch processors (Loongson-3 series) support DVFS, their
> IOCSR.FEATURES has IOCSRF_FREQSCALE set. And they has a micro-core in
> the package called SMC (System Management Controller), which can be
> used to detect temperature, control fans, scale frequency and voltage,
> etc.
> 
> The Loongson-3 CPUFreq driver is very simple now, it communicate with
> SMC, get DVFS info, set target frequency from CPUFreq core, and so on.
> 
> There is a command list to interact with SMC, widely-used commands in
> the CPUFreq driver include:
> 
> CMD_GET_VERSION: Get SMC firmware version.
> 
> CMD_GET_FEATURE: Get enabled SMC features.
> 
> CMD_SET_FEATURE: Enable SMC features, such as basic DVFS, BOOST.
> 
> CMD_GET_FREQ_LEVEL_NUM: Get the number of all frequency levels.
> 
> CMD_GET_FREQ_BOOST_LEVEL: Get the first boost frequency level.
> 
> CMD_GET_FREQ_LEVEL_INFO: Get the detail info of a frequency level.
> 
> CMD_GET_FREQ_INFO: Get the current frequency.
> 
> CMD_SET_FREQ_INFO: Set the target frequency.
> 
> In future we will add automatic frequency scaling, which is similar to
> Intel's HWP (HardWare P-State).
> 
> Signed-off-by: Binbin Zhou <zhoubinbin@...ngson.cn>
> Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn

Hi Huacai,

I got some error with the driver enabled:

[    6.650403] BUG: using smp_processor_id() in preemptible [00000000] code: (udev-worker)/208
[    6.658719] caller is loongson3_cpufreq_probe+0x5c/0x250 [loongson3_cpufreq]

and the driver failed to probe.

It seems the caller of smp_processor_id is actually do_service_request,
which is inlined into loongson3_cpufreq_probe.

The .config file is attached.

-- 
Xi Ruoyao <xry111@...111.site>
School of Aerospace Science and Technology, Xidian University

Download attachment "config.gz" of type "application/gzip" (24397 bytes)