[PATCH v2 08/57] x86: acpi: Support external GNVS tables

[Simon Glass]

Hi Wolfgang,

On Fri, 4 Sep 2020 at 08:16, Wolfgang Wallner
<wolfgang.wallner at br-automation.com> wrote:
>
> Hi Simon, Bin,
>
> -----"Simon Glass" <sjg at chromium.org> schrieb: -----
> > Betreff: [PATCH v2 08/57] x86: acpi: Support external GNVS tables
> >
> > At present U-Boot puts a magic number in the ASL for the GNVS table and
> > searches for it later.
> >
> > Add a Kconfig option to use a different approach, where the ASL files
> > declare the table as an external symbol. U-Boot can then put it wherever
> > it likes, without any magic numbers or searching.
> >
> > Signed-off-by: Simon Glass <sjg at chromium.org>
> > ---
>
> [snip]
> > diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
> [snip]
> >       acpi_inc_align(ctx, dsdt->length - sizeof(struct acpi_table_header));
> > +     dsdt->length = ctx->current - (void *)dsdt;
>
> While testing the latest series of ACPI patches I saw strange behavior when
> booting Linux. Sometimes it would boot, sometimes it would hang, sometimes it
> would boot but show ACPI-related errors in dmesg.
>
> Debugging showed that the reason is that the calculated length of the DSDT
> in the above code includes any additional bytes that were added for alignment,
> and those are not initialized. I gues the Linux ACPI implementation tries to
> decode those, and then something crashes.
>
> Changing the above two lines to the following
>
>    acpi_inc(ctx, dsdt->length - sizeof(struct acpi_table_header));
>    dsdt->length = ctx->current - (void *)dsdt;
>    acpi_align(ctx);
>
> fixes the issue for me.
>
> But the issue already exists in the previous code. Would it be better to
> send a patch which applies to the currrent master, or on top of the ACPI series?

I think to the current master would be better. I have seen that
problem so thank you for figuring it out!

Regards,
SImon