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Message-ID: <2c23ab17-7516-e310-8b79-b8c5fc02984a@redhat.com>
Date:   Mon, 18 Sep 2023 13:33:37 +1000
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Subject: Re: [RFC PATCH v2 05/35] drivers: base: Print a warning instead of
 panic() when register_cpu() fails
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To:     James Morse <james.morse@arm.com>, linux-pm@vger.kernel.org,
        loongarch@lists.linux.dev, linux-acpi@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev
Cc:     x86@kernel.org, Salil Mehta <salil.mehta@huawei.com>,
        Russell King <linux@armlinux.org.uk>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        jianyong.wu@arm.com, justin.he@arm.com
References: <20230913163823.7880-1-james.morse@arm.com>
 <20230913163823.7880-6-james.morse@arm.com>
From:   Gavin Shan <gshan@redhat.com>
In-Reply-To: <20230913163823.7880-6-james.morse@arm.com>
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On 9/14/23 02:37, James Morse wrote:
> loongarch, mips, parisc, riscv and sh all print a warning if
> register_cpu() returns an error. Architectures that use
> GENERIC_CPU_DEVICES call panic() instead.
> 
> Errors in this path indicate something is wrong with the firmware
> description of the platform, but the kernel is able to keep running.
> 
> Downgrade this to a warning to make it easier to debug this issue.
> 
> This will allow architectures that switching over to GENERIC_CPU_DEVICES
> to drop their warning, but keep the existing behaviour.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>   drivers/base/cpu.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index 579064fda97b..d31c936f0955 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -535,14 +535,15 @@ int __weak arch_register_cpu(int cpu)
>   
>   static void __init cpu_dev_register_generic(void)
>   {
> -	int i;
> +	int i, ret;
>   
>   	if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES))
>   		return;
>   
>   	for_each_present_cpu(i) {
> -		if (arch_register_cpu(i))
> -			panic("Failed to register CPU device");
> +		ret = arch_register_cpu(i);
> +		if (ret)
> +			pr_warn("register_cpu %d failed (%d)\n", i, ret);
>   	}
>   }
>   

The same warning message has been printed by arch/loongarch/kernel/topology.c::arch_register_cpu().
In order to avoid the duplication, I think the warning message in arch/loongarch needs to be dropped?

Thanks,
Gavin