linux-kernel - Re: [PATCH] ACPI: Only evaluate the Intel _OSC and

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 for Android: free password hash cracker in your pocket

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

Date: Sat, 15 Jun 2024 12:38:02 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Mario Limonciello <mario.limonciello@....com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, "open list:ACPI" <linux-acpi@...r.kernel.org>, 
	open list <linux-kernel@...r.kernel.org>, 
	PradeepVineshReddy Kodamati <PradeepVineshReddy.Kodamati@....com>, CL Lin <clin41@...ovo.com>
Subject: Re: [PATCH] ACPI: Only evaluate the Intel _OSC and _PDC on platforms
 with HWP

On Fri, Jun 14, 2024 at 9:33 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> The UUID 4077A616-290C-47BE-9EBD-D87058713953 and _PDC methods are
> only used on Intel platforms with HWP support.

I beg to differ.  See arch_acpi_set_proc_cap_bits() definition.

> Attempting to evaluate them and showing messages on hardware without
> HWP is pointless needlessly noisy.
>
> Gate the code on X86_FEATURE_HWP.

Not really.

> Cc: PradeepVineshReddy (Pradeep Vinesh Reddy) Kodamati <PradeepVineshReddy.Kodamati@....com>
> Suggested-by: CL Lin <clin41@...ovo.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
>  drivers/acpi/acpi_processor.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 7a0dd35d62c9..84848b5e65d6 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -597,6 +597,8 @@ static bool __init acpi_early_processor_osc(void)
>
>  void __init acpi_early_processor_control_setup(void)
>  {
> +       if (!boot_cpu_has(X86_FEATURE_HWP))
> +               return;
>         if (acpi_early_processor_osc()) {
>                 pr_info("_OSC evaluated successfully for all CPUs\n");
>         } else {
> --
> 2.43.0
>