linux-kernel - Re: [PATCH] cpufreq: loongson3: Use raw_smp_processor_id() in do_service

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Message-ID: <CAAhV-H6YLg1ipUf-45-0zF6HRcCfkVikwQM5cAD7_VSYyAsfoQ@mail.gmail.com>
Date: Wed, 28 Aug 2024 21:55:25 +0800
From: Huacai Chen <chenhuacai@...nel.org>
To: Xi Ruoyao <xry111@...111.site>
Cc: Huacai Chen <chenhuacai@...ngson.cn>, "Rafael J . Wysocki" <rafael@...nel.org>, 
	Viresh Kumar <viresh.kumar@...aro.org>, 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] cpufreq: loongson3: Use raw_smp_processor_id() in do_service_request()

On Wed, Aug 28, 2024 at 7:59 PM Xi Ruoyao <xry111@...111.site> wrote:
>
> On Wed, 2024-08-28 at 14:24 +0800, Huacai Chen wrote:
> > Use raw_smp_processor_id() instead of plain smp_processor_id() in
> > do_service_request(), otherwise we may get some errors with the driver
> > enabled:
> >
> >  BUG: using smp_processor_id() in preemptible [00000000] code: (udev-
> > worker)/208
> >  caller is loongson3_cpufreq_probe+0x5c/0x250 [loongson3_cpufreq]
> >
> > Reported-by: Xi Ruoyao <xry111@...111.site>
> > Tested-by: Binbin Zhou <zhoubinbin@...ngson.cn>
> > Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
>
> Tested-by: Xi Ruoyao <xry111@...111.site>
>
> After this patch the BUG() message is gone, but I still get
>
> [    6.610357] loongson3_cpufreq loongson3_cpufreq: probe with driver loongson3_cpufreq failed with error -1
>
> -1 is EPERM and there are several "return -EPERM;" in the code.  Not
> sure which one.
>
> Do I need to modify some firmware setting to make it work?
You should update your firmware.

>
> FWIW I'm building it as a module.  Should I try building it as a part of
> vmlinux?
No need.

Huacai

>
> > ---
> >  drivers/cpufreq/loongson3_cpufreq.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/loongson3_cpufreq.c
> > b/drivers/cpufreq/loongson3_cpufreq.c
> > index 5f79b6de127c..6b5e6798d9a2 100644
> > --- a/drivers/cpufreq/loongson3_cpufreq.c
> > +++ b/drivers/cpufreq/loongson3_cpufreq.c
> > @@ -176,7 +176,7 @@ static DEFINE_PER_CPU(struct loongson3_freq_data
> > *, freq_data);
> >  static inline int do_service_request(u32 id, u32 info, u32 cmd, u32
> > val, u32 extra)
> >  {
> >       int retries;
> > -     unsigned int cpu = smp_processor_id();
> > +     unsigned int cpu = raw_smp_processor_id();
> >       unsigned int package = cpu_data[cpu].package;
> >       union smc_message msg, last;
> >
>
> --
> Xi Ruoyao <xry111@...111.site>
> School of Aerospace Science and Technology, Xidian University
>