linux-kernel - Re: [PATCH 34/39] arm64: psci: Ignore DENIED CPUs

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Message-ID: <ZVsl1ZQ9JRXPf4qH@shell.armlinux.org.uk>
Date:   Mon, 20 Nov 2023 09:24:37 +0000
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Jianyong Wu <Jianyong.Wu@....com>
Cc:     "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "loongarch@...ts.linux.dev" <loongarch@...ts.linux.dev>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-riscv@...ts.infradead.org" <linux-riscv@...ts.infradead.org>,
        "kvmarm@...ts.linux.dev" <kvmarm@...ts.linux.dev>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-csky@...r.kernel.org" <linux-csky@...r.kernel.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        "linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>,
        "linux-parisc@...r.kernel.org" <linux-parisc@...r.kernel.org>,
        Salil Mehta <salil.mehta@...wei.com>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>,
        Justin He <Justin.He@....com>,
        James Morse <James.Morse@....com>,
        Catalin Marinas <Catalin.Marinas@....com>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <Mark.Rutland@....com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>
Subject: Re: [PATCH 34/39] arm64: psci: Ignore DENIED CPUs

On Thu, Nov 16, 2023 at 07:45:51AM +0000, Jianyong Wu wrote:
> Hi Russell,
> 
> One inline comment.
...
> > Changes since RFC v2
> >  * Add specification reference
> >  * Use EPERM rather than EPROBE_DEFER
...
> > @@ -40,7 +40,7 @@ static int cpu_psci_cpu_boot(unsigned int cpu)  {
> >  	phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
> >  	int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
> > -	if (err)
> > +	if (err && err != -EPROBE_DEFER)
> 
> Should this be EPERM? As the following psci cpu_on op will return it. I
> think you miss to change this when apply Jean-Philippe's patch.

It looks like James didn't properly update all places. Also,

> > diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c index
> > d9629ff87861..ee82e7880d8c 100644
> > --- a/drivers/firmware/psci/psci.c
> > +++ b/drivers/firmware/psci/psci.c
> > @@ -218,6 +218,8 @@ static int __psci_cpu_on(u32 fn, unsigned long cpuid,
> > unsigned long entry_point)
> >  	int err;
> > 
> >  	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
> > +	if (err == PSCI_RET_DENIED)
> > +		return -EPERM;
> >  	return psci_to_linux_errno(err);

This change is unnecessary - probably comes from when -EPROBE_DEFER was
being used. psci_to_linux_errno() already does:

       case PSCI_RET_DENIED:
               return -EPERM;

Thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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