Re: [PATCH] ACPI / sysfs: Extend ACPI sysfs to provide access to boot error region

[Alan Cox]

On Thu, 17 Aug 2017 14:39:46 -0700
"Luck, Tony" <tony.luck@xxxxxxxxx> wrote:

> From: Tony Luck <tony.luck@xxxxxxxxx>
> 
> The ACPI sysfs interface provides a way to read each ACPI table from
> userspace via entries in /sys/firmware/acpi/tables/
> 
> The BERT table simply provides the size and address of the error
> record in BIOS reserved memory and users may want access to this
> record.
> 
> In an earlier age we might have used /dev/mem to retrieve this error
> record, but many systems disable /dev/mem for security reasons.
> 
> Extend this driver to provide read-only access to the data via a
> file in a new directory /sys/firmware/acpi/tables/data/BERT

Should this not also have a capability check. Assuming file permissions
are sufficient for grabbing a chunk of system memory holding error
info doesn't seem too scary but it's at odds with a lot of other cases ?

Alan