[PATCH v2] ACPI: Add config to disable ACPI SPCR console by default on arm64
Liu Wei
liuwei09 at cestc.cn
Fri Jun 21 09:39:25 PDT 2024
From: Prarit Bhargava <prarit at redhat.com>
On 6/21/24 00:47, Liu Wei wrote:
> > For varying privacy and security reasons, sometimes we would like to
> > completely silence the serial console output, and only enable it through
> > cmdline when needed.
> >
> > But there are many existing systems that depend on this console,
> > so add CONFIG_ARM_DISABLE_ACPI_SPCR_CONSOLE for this situation.
> >
> > Signed-off-by: Liu Wei <liuwei09 at cestc.cn>
> > Suggested-by: Prarit Bhargava <prarit at redhat.com>
> > ---
> >
> > v2: Add a config option suggested by Prarit
> > ---
> > arch/arm64/kernel/acpi.c | 12 ++++++++++++
> > drivers/acpi/arm64/Kconfig | 11 +++++++++++
> > 2 files changed, 23 insertions(+)
> >
> > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> > index dba8fcec7f33..3365fabb5cf8 100644
> > --- a/arch/arm64/kernel/acpi.c
> > +++ b/arch/arm64/kernel/acpi.c
> > @@ -227,7 +227,19 @@ void __init acpi_boot_table_init(void)
> > if (earlycon_acpi_spcr_enable)
> > early_init_dt_scan_chosen_stdout();
> > } else {
> > + /*
> > + * For varying privacy and security reasons, sometimes need
> > + * to completely silence the serial console output, and only
> > + * enable it by cmdline when needed.
> > + * But there are many existing systems that depend on this
> > + * behavior, so use CONFIG_ARM_DISABLE_ACPI_SPCR_CONSOLE.
> > + */
> > +#ifdef CONFIG_ARM_DISABLE_ACPI_SPCR_CONSOLE
> > + acpi_parse_spcr(earlycon_acpi_spcr_enable, false);
> > +#else
> > acpi_parse_spcr(earlycon_acpi_spcr_enable, true);
> > +#endif
> > +
>
> I don't think you want a config option here after all. See my previous
> comment about "acpi=nospcr". I realized that if you do use a config
> then distros will not have the ability to default 'on', and advise users
> to disable it for their use cases.
>
> Try the 'acpi=nospcr' option. That should keep everyone happy.
>
Ok, I will send new version soon.
Thanks for your suggestion!
Liu Wei
> P.
>
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