linux-kernel - Re: [PATCH v2 3/3] cpufreq: amd-pstate: Add a module device table

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: <YkKfqFqmKWMUAvBF@amd.com>
Date:   Tue, 29 Mar 2022 13:56:56 +0800
From:   Huang Rui <ray.huang@....com>
To:     "Limonciello, Mario" <Mario.Limonciello@....com>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        "open list:AMD PSTATE DRIVER" <linux-pm@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/3] cpufreq: amd-pstate: Add a module device table

On Tue, Mar 29, 2022 at 09:59:47AM +0800, Limonciello, Mario wrote:
> `amd-pstate` currently only loads automatically if compiled into the
> kernel.  To improve the usability, add a module device table that
> will load when AMD CPUs that support CPPC are detected.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>

Reviewed-by: Huang Rui <ray.huang@....com>

> ---
> v1->v2:
>  * Add comment to indicate need of SBIOS support.
> 
>  drivers/cpufreq/amd-pstate.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 7dc2e344f222..9f78849654e7 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -705,6 +705,17 @@ static void __exit amd_pstate_exit(void)
>  	amd_pstate_enable(false);
>  }
>  
> +/*
> + * This will only match the HW feature, there still needs to be appropriate
> + * SBIOS support, so it's possible that in such cases this causes a module
> + * load with -ENODEV as the result.
> + */
> +static const struct x86_cpu_id __maybe_unused amd_pstate_ids[] = {
> +	X86_MATCH_VENDOR_FEATURE(AMD, X86_FEATURE_CPPC, NULL),
> +	{}
> +};
> +MODULE_DEVICE_TABLE(x86cpu, amd_pstate_ids);
> +
>  module_init(amd_pstate_init);
>  module_exit(amd_pstate_exit);
>  
> -- 
> 2.34.1
>